JP4307779B2

JP4307779B2 - Battery pack manufacturing method

Info

Publication number: JP4307779B2
Application number: JP2002034926A
Authority: JP
Inventors: 克巳高津; 毅石丸; 善樹大澤; 智志片岡; 猪一郎森; 幸一鳥山; 雅博水田; 辰久近田
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2002-02-13
Filing date: 2002-02-13
Publication date: 2009-08-05
Anticipated expiration: 2022-02-13
Also published as: JP2003242947A

Description

【０００１】
【発明の属する技術分野】
本発明は、小型の携帯電子機器等の電池電源に適するように構成要素を樹脂充填により一体化し、小型化並びに堅牢性の向上を図った電池パックの製造方法に関するものである。
【０００２】
【従来の技術】
携帯電話機やＰＤＡなどの携帯電子機器の小型化あるいは薄型化、更には高機能化の進展は著しく、それに対応してその電源となる電池に小型、薄型で高容量化が要求されている。小型で高容量化を可能にする電池としてリチウムイオン二次電池が有効であり、中でも扁平な角形のものは機器の薄型化に好適であり、繰り返し使用ができる二次電池として携帯電子機器への適用が増加している。
【０００３】
前記リチウムイオン二次電池はエネルギー密度が高く、電解液として可燃性の有機溶媒を用いているため、安全性への配慮が重要となる。何らかの原因によって異常が生じたときにも人体や機器に損傷を与えないように安全性を確保する必要がある。例えば、電池の正極端子と負極端子との間が何らかの原因によって短絡した場合、エネルギー密度の高い電池では過大な短絡電流が流れ、内部抵抗によってジュール熱が発生して電池は温度上昇する。電池が高温になると正極板活物質と電解液との反応や電解液の気化、分解などが生じて電池内部のガス圧が急上昇し、電池は破裂や発火に至る恐れがある。電池が高温状態に陥る原因は上記外部短絡だけでなく、二次電池を過充電した場合や、電池を装填した携帯電子機器を暖房機の傍らに置いたり、炎天下に駐車した車内に放置した場合なども該当する。
【０００４】
電池が異常な状態に陥る原因は、電気的、機械的、熱的など種々の要因が考えられ、リチウムイオン二次電池をはじめとする非水電解質二次電池では、電池が異常状態に陥ることを防止すると共に、異常状態に陥った場合にも危険な状態にならないようにする機能が設けられる。電池自体の機能として、極板の活物質や電解液が過剰な反応を起こしにくいように工夫され、セパレータとして用いられるポリオレフィン系微多孔膜は異常な高温になると軟化して細孔が塞がれることによるシャットダウン機能が備わっている。また、円筒形のリチウムイオン二次電池では、封口部に入出力回路と直列に接続したＰＴＣ（ＰｏｓｉｔｉｖｅＴｈｅｒｍａｌＣｏｅｆｆｃｉｅｎｔ）素子を配設して、外部短絡による過大電流を制限する保護機能が設けられている。電池内に前記ＰＴＣ素子が設けられていない電池では、外付けの回路部品としてＰＴＣ素子や温度ヒューズが配線接続され、更に過充電や過放電等から電池を保護する電池保護回路を設けるのが必須要件となっており、これらの構成要素を二次電池と共にパックケース内に収容して電池パックの形態に構成されのが一般的である。
【０００５】
しかし、前記パックケースを形成するための樹脂成形金型は、その製作費用が高く、開発期間も長くなるので、新機種の投入期間が短い携帯電子機器などに対応できない。また、前述のように携帯電子機器の小型化、薄型化に対応する電池パックを構成するには、樹脂成形の成形可能な肉厚の限度があり、樹脂成形による外装ケースに限界がある。
【０００６】
また、電池パックは、それを分解して間違った使用や興味本位で使用されることを防ぐために、分解し難いように構成することや、分解したことが分かるように構成することが安全確保上で重要である。また、携帯電子機器に適用されることを考慮すると、落下等による衝撃や振動に耐え得る堅牢な構造や電子回路部位の耐湿性が要求される。このような分解し難く堅牢且つ耐湿性を有する構造を実現すべく、電池保護回路等を構成した回路基板と電池とを樹脂モールディングにより一体化することが構想されている。
【０００７】
上記樹脂モールディングによる電池パックは、本願出願人により特願２０００−３２０１６６号、特願２０００−３６３５１８号として提案したものがあり、電池と回路基板とを接続部材により接続した中間完成品を金型内に配置し、回路基板に形成した外部接続端子が外部露出するようにして中間完成品の周囲に樹脂を充填して二次電池と回路基板とを一体化している。
【０００８】
また、特開２０００−３１５４８３号に開示されたものでは、電池と回路基板とを接続部材により接続したものを金型内に配置し、回路基板を樹脂封止して電池上又はパックケース（電池蓋体）に固定する構成、あるいは回路基板と電池とを樹脂封止する構成が開示されている。
【０００９】
【発明が解決しようとする課題】
上記特開２０００−３１５４８３号に開示された構成は、樹脂封止された中の回路基板から外に引き出したリード線の先端にコネクタが設けられており、機器との接続は機器側のコネクタと雄雌間の嵌合によってなされる。この外部接続構造は比較的大型の機器で電池収容スペースに余裕がある場合には問題はないが、本願発明の電池パックが主目的とする小型の機器では電池収容スペースに余裕が少ないのが当然で、この接続構造を適用することは困難である。本願発明の電池パックの機器側との接続構造は、機器側の電池収容スペースに電池パックを収納したとき、そこに設けられた機器側接触端子（プローブ）が電池パックの所定位置に外部露出する外部接続端子に圧接するようにしたものである。
【００１０】
外部接続端子を形成した回路基板と電池とを樹脂モールディングして電池パックに構成し、機器側の電池収容スペースに設けられた機器側接続端子と前記外部接続端子とが接触抵抗が小さい状態に圧接させるには、電池パックの外形寸法及び外部接続端子の位置は高精度に形成する必要がある。このような接触による接続の場合に、形成精度が低いと、機器側接続端子と外部接続端子との接触抵抗が大きくなり、接触不良や電圧降下などの異常を来すことになる。
【００１１】
特に、回路基板に外部接続端子を形成し、この回路基板を電池の封口板と並行になる位置に配設した構成では、図１９に示すように、電池パック１００の底面から回路基板１０２の外部接続端子１０３の形成面までの寸法Ｌが精度よく仕上げられることが必要である。しかし、電池１０１の高さ寸法ｈにはバラツキがあり、回路基板１０２は接続部材１０４によって電池１０１と接続されているだけで、その位置、角度は変動しやすい状態にある。一般的に採用される電池パックの構成では、電池１０１及び回路基板１０２はパックケースに位置決め固定されるので、前記寸法Ｌは規制することができる。樹脂モールディングによって電池１０１と回路基板１０２とを一体化する構成では、電池１０１の高さ寸法ｈのバラツキを吸収し、回路基板１０２を位置決めして樹脂モールディングする必要がある。
【００１２】
従来は樹脂モールディングにより電池パックを形成した場合に、その高さ寸法を精度よく成形することが困難であるため、前述のコネクタによる接続構造や、機器の電池収容スペースにバネ等の付勢手段を設けて収納された電池パックを機器の接続端子側に付勢し、寸法のバラツキを吸収する構造や、電池パックの長側面の端部に外部接続端子を露出させ、機器の電池収容スペースに電池パックを挿入したとき、弾性構造の機器側接続端子が外部接続端子に摺動接触することにより接触不良を解消する構造が採用されていた。しかし、これらの構造は機器側の電池パックの収容スペースが増加し、電池パック接続のための部材が増え、機器の小型化を損なうことになるため、携帯電話機のようにスペースに余裕がない小型の電子機器では適用し難い構造であった。
【００１３】
本発明が目的とするところは、電池と回路基板とを樹脂モールディングにより一体化して電池パックに構成するとき、その外形寸法及び外部接続端子の位置が精度よく仕上がるようにした電池パックの製造方法を提供することにある。
【００１４】
【課題を解決するための手段】
上記目的を達成するための本願第１発明に係る電池パックの製造方法は、一方面に外部接続端子を形成した回路基板を接続部材により扁平長方形に形成された二次電池の封口板に接続すると共に、回路基板をその他方面が封口板に対向するように間隙を隔てて配置して樹脂充填対象物を形成し、この樹脂充填対象物を二次電池及び回路基板を所定位置に位置決めして金型内に配置し、二次電池と回路基板との間の間隙に樹脂を充填する樹脂成形を行って二次電池と回路基板とを一体化した中間完成品を形成し、この中間完成品の少なくとも外部接続端子を外部露出させて外装被覆を形成することを特徴とするものである。
【００１５】
上記第１発明の製造方法によれば、回路基板を二次電池に接続した樹脂充填対象物を、金型内の所定位置に回路基板及び二次電池を位置決めして収容し、二次電池と回路基板とに間の間隔内に樹脂を充填すると、二次電池と回路基板とを一体化して二次電池の底面から回路基板の外部接続端子の形成面までの寸法を所定値にした中間完成品に形成することができる。この中間完成品に外装被覆を形成すると、分解し難く堅牢構造の電池パックを構成することができる。
【００１６】
また、本願第２Ａ発明に係る電池パックの製造方法は、一方面に外部接続端子を形成した回路基板を接続部材により扁平長方形に形成された二次電池の封口板に接続すると共に、回路基板をその他方面が封口板に対向するように間隙を隔てて配置して樹脂充填対象物を形成し、この樹脂充填対象物を二次電池及び回路基板を所定位置に位置決めして金型内に配置し、二次電池と回路基板との間の樹脂充填空間に樹脂を充填する樹脂成形を行って二次電池と回路基板とを一体化した中間完成品を形成し、この中間完成品の少なくとも外部接続端子を外部露出させて外装被覆を形成する電池パックの製造方法であって、前記金型として、二次電池を収容保持する電池保持部と、回路基板を真空吸着により位置決め保持する基板位置決め用壁面、二次電池の封口板側の両肩部に当接して二次電池の位置決めを行う左右1対の電池位置決め用壁面、および基板位置決め用壁面と左右1対の電池位置決め用壁面のそれぞれとを繋ぐ位置決めされた回路基板面に直角な方向の側面壁を備え、かつ、前記二次電池の封口板に対する離接方向に移動可能な基板保持部と、前記基板保持部を付勢して、前記電池位置決め用壁面を二次電池の前記両肩部に当接させる付勢手段とを備え、前記電池位置決め用壁面が二次電池の前記両肩部に当接したときに、前記基板位置決め用壁面に位置決めされた回路基板と、二次電池の封口板と、前記側面壁とによって囲まれる空間が樹脂充填空間となるように構成された金型を用い、前記樹脂充填対象物を、その回路基板を前記基板位置決め用壁面に真空吸着させて位置決めし、その二次電池を前記電池保持部に収容保持させ、前記基板保持部を付勢手段で付勢して、前記電池位置決め用壁面を二次電池の前記両肩部に当接させた状態で、前記金型内に配置し、前記樹脂充填空間に樹脂を充填して樹脂成形を行うことによって前記中間完成品を得ることを特徴とするものである。
本願第２Ｂ発明に係る電池パックの製造方法は、一方面に外部接続端子を形成した回路基板を接続部材により扁平長方形に形成された二次電池の封口板に接続すると共に、回路基板をその他方面が封口板に対向するように間隙を隔てて配置して樹脂充填対象物を形成し、この樹脂充填対象物を二次電池及び回路基板を所定位置に位置決めして金型内に配置し、二次電池と回路基板との間の樹脂充填空間に樹脂を充填する樹脂成形を行って二次電池と回路基板とを一体化した中間完成品を形成し、この中間完成品の少なくとも外部接続端子を外部露出させて外装被覆を形成する電池パックの製造方法であって、前記金型として、二次電池を、回路基板に対する離接方向に移動可能に収容保持する電池保持部と、回路基板を真空吸着により位置決め保持する基板位置決め用壁面、二次電池の封口板側の両肩部に当接して二次電池の位置決めを行う左右1対の電池位置決め用壁面、および基板位置決め用壁面と左右1対の電池位置決め用壁面のそれぞれとを繋ぐ位置決めされた回路基板面に直角な方向の側面壁を備えた基板保持部と、前記二次電池を付勢して、二次電池の前記両肩部を前記電池位置決め用壁面に当接させる付勢手段とを備え、二次電池の前記両肩部が前記電池位置決め用壁面に当接したときに、前記基板位置決め用壁面に位置決め保持された回路基板と、二次電池の封口板と、前記側面壁とによって囲まれる空間が樹脂充填空間となるように構成された金型を用い、前記樹脂充填対象物を、その回路基板を前記基板位置決め用壁面に真空吸着させて位置決めし、その二次電池を前記電池保持部に収容保持させ、二次電池を付勢手段で付勢して、二次電池の前記両肩部を前記電池位置決め用壁面に当接させた状態で、前記金型内に配置し、前記樹脂充填空間に樹脂を充填して樹脂成形を行うことによって前記中間完成品を得ることを特徴とするものである。
【００１７】
上記第２Ａ発明、第２Ｂ発明の製造方法によれば、二次電池の底面側が電池位置決め用壁面に当接するように付勢し、回路基板を基板位置決め用壁面に真空吸着した状態にして、二次電池と回路基板とをその間の間隙に樹脂を充填して一体化すると、二次電池の高さ寸法のバラツキ及び位置規制されない状態にある回路基板の位置のバラツキは、充填された樹脂の高さ寸法の変化によって吸収され、中間完成品の高さ寸法は一定に仕上げられる。この中間完成品の外部接続端子を含む所定部位を外部露出させて外装被覆を形成すると、外部接続端子の位置が精度よく位置決めされ、分解し難く堅牢構造の電池パックに形成できる。また、二次電池の封口板側が電池位置決め用壁面に当接するように付勢し、回路基板を基板位置決め用壁面に真空吸着した状態にして、二次電池と回路基板とをその間の間隙に樹脂を充填して一体化すると、二次電池と回路基板とは樹脂により一定間隔に結合された状態が得られる。二次電池の高さ寸法のバラツキは中間完成品の高さ寸法の変化となるが、外装被覆を行う二次成形時に外形寸法が一定になるように樹脂成形するとき、二次電池の底面側の厚さ変化によって吸収される。
【００１８】
また、本願第３Ａ発明に係る電池パックの製造方法は、一方面に外部接続端子を形成した回路基板を接続部材により扁平長方形に形成された二次電池の封口板に接続すると共に、回路基板をその他方面が封口板に対向するように間隙を隔てて配置して樹脂充填対象物を形成し、この樹脂充填対象物を二次電池及び回路基板を所定位置に位置決めして金型内に配置し、二次電池と回路基板との間の樹脂充填空間に樹脂を充填する樹脂成形を行って二次電池と回路基板とを一体化した中間完成品を形成し、この中間完成品の少なくとも外部接続端子を外部露出させて外装被覆を形成する電池パックの製造方法であって、前記金型として、二次電池を収容保持する電池保持部と、回路基板の二次電池対向面の両端に当接して回路基板の位置決めを行う左右１対の基板位置決め用壁面、回路基板を前記両端が前記基板位置決め用壁面に当接するように付勢する付勢手段、二次電池の封口板側の両肩部に当接して二次電池の位置決めを行う左右1対の電池位置決め用壁面、および左右１対の基板位置決め用壁面と左右1対の電池位置決め用壁面のそれぞれとを繋ぐ位置決めされた回路基板に直角な方向の側面壁を備えた基板保持部と、前記基板保持部を付勢して、前記電池位置決め用壁面を二次電池の前記両肩部に当接させる付勢手段とを備え、前記電池位置決め用壁面が二次電池の前記両肩部に当接したときに、前記基板位置決め用壁面に位置決めされた回路基板と、二次電池の封口板と、前記側面壁とによって囲まれる空間が樹脂充填空間となるように構成された金型を用い、前記樹脂充填対象物を、その回路基板を前記付勢手段で付勢して前記基板位置決め用壁面に位置決めし、その二次電池を前記電池保持部に収容保持させ、前記基板保持部を付勢手段で付勢して、前記電池位置決め用壁面を二次電池の前記両肩部に当接させた状態で、前記金型内に配置し、前記樹脂充填空間に樹脂を充填して樹脂成形を行うことによって前記中間完成品を得ることを特徴とするものである。
本願第３Ｂ発明に係る電池パックの製造方法は、一方面に外部接続端子を形成した回路基板を接続部材により扁平長方形に形成された二次電池の封口板に接続すると共に、回路基板をその他方面が封口板に対向するように間隙を隔てて配置して樹脂充填対象物を形成し、この樹脂充填対象物を二次電池及び回路基板を所定位置に位置決めして金型内に配置し、二次電池と回路基板との間の樹脂充填空間に樹脂を充填する樹脂成形を行って二次電池と回路基板とを一体化した中間完成品を形成し、この中間完成品の少なくとも外部接続端子を外部露出させて外装被覆を形成する電池パックの製造方法であって、前記金型として、二次電池を、回路基板に対する離接方向に移動可能に収容保持する電池保持部と、回路基板の二次電池対向面の両端に当接して回路基板の位置決めを行う左右１対の基板位置決め用壁面、回路基板を前記両端が前記基板位置決め用壁面に当接するように付勢する付勢手段、二次電池の封口板側の両肩部に当接して二次電池の位置決めを行う左右1対の電池位置決め用壁面、および左右１対の基板位置決め用壁面と左右1対の電池位置決め用壁面のそれぞれとを繋ぐ位置決めされた回路基板に直角な方向の側面壁を備えた基板保持部と、前記二次電池を付勢して、二次電池の前記両肩部を前記電池位置決め用壁面に当接させる付勢手段とを備え、二次電池の前記両肩部が前記電池位置決め用壁面に当接したときに、前記基板位置決め用壁面に位置決め保持された回路基板と、二次電池の封口板と、前記側面壁とによって囲まれる空間が樹脂充填空間となるように構成された金型を用い、前記樹脂充填対象物を、その回路基板を前記付勢手段で付勢して前記基板位置決め用壁面に位置決めし、その二次電池を前記電池保持部に収容保持させ、二次電池を付勢手段で付勢して、二次電池の前記両肩部を前記電池位置決め用壁面に当接させた状態で、前記金型内に配置し、前記樹脂充填空間に樹脂を充填して樹脂成形を行うことによって前記中間完成品を得ることを特徴とするものである。
【００１９】
上記第３Ａ発明、第３Ｂ発明の製造方法によれば、金型内に形成された基板位置決め用壁面に回路基板が当接するように付勢し、電池位置決め用壁面に二次電池の封口板側が当接するように付勢すると、二次電池と回路基板との間の間隙は一定の寸法に位置決めされ、この間隙内に樹脂が充填成形されることにより二次電池と回路基板とが一体化される。このように形成された中間完成品は二次電池の高さ寸法のバラツキにより高さ寸法にバラツキが生じる。この高さ寸法のバラツキは、外装被覆を行う二次成形時に外形寸法が一定になるように樹脂成形するとき、二次電池の底面側の厚さ変化によって吸収される。また、基板位置決め用壁面に二次電池の底面側が当接するように付勢した場合には、回路基板は基板位置決め用壁面に当接するように付勢して、二次電池と回路基板とをその間の間隙に樹脂を充填して一体化すると、二次電池の高さ寸法のバラツキ及び位置規制されない状態にある回路基板の位置のバラツキは、充填された樹脂の高さ寸法の変化によって吸収され、中間完成品の高さ寸法は一定に仕上げられる。
【００２０】
また、本願第４Ａ発明に係る電池パックの製造方法は、一方面に外部接続端子を形成した回路基板を接続部材により扁平長方形に形成された二次電池の封口板に接続すると共に、回路基板をその他方面が封口板に対向するように間隙を隔てて配置して樹脂充填対象物を形成し、この樹脂充填対象物を二次電池及び回路基板を所定位置に位置決めして金型内に配置し、二次電池と回路基板との間の樹脂充填空間に樹脂を充填する樹脂成形を行って二次電池と回路基板とを一体化した中間完成品を形成し、この中間完成品の少なくとも外部接続端子を外部露出させて外装被覆を形成する電池パックの製造方法であって、前記金型として、二次電池を収容保持する電池保持部と、回路基板の両端を嵌合保持して回路基板の位置決めを行う左右１対の基板位置決め用溝、二次電池の封口板側の両肩部に当接して二次電池の位置決めを行う左右1対の電池位置決め用壁面、および左右１対の基板位置決め用溝と左右1対の電池位置決め用壁面のそれぞれとを繋ぐ位置決めされた回路基板に直角な方向の側面壁を備えた基板保持部と、前記基板保持部を付勢して、前記電池位置決め用壁面を二次電池の前記両肩部に当接させる付勢手段とを備え、前記電池位置決め用壁面が二次電池の前記両肩部に当接したときに、前記基板位置決め用溝に位置決めされた回路基板と、二次電池の封口板と、前記側面壁とによって囲まれる空間が樹脂充填空間となるように構成された金型を用い、前記樹脂充填対象物を、その回路基板を前記基板位置決め用溝に位置決めし、その二次電池を前記電池保持部に収容保持させ、前記基板保持部を付勢手段で付勢して、前記電池位置決め用壁面を二次電池の前記両肩部に当接させた状態で、前記金型内に配置し、前記樹脂充填空間に樹脂を充填して樹脂成形を行うことによって前記中間完成品を得ることを特徴とするものである。
本願第４Ｂ発明に係る電池パックの製造方法は、一方面に外部接続端子を形成した回路基板を接続部材により扁平長方形に形成された二次電池の封口板に接続すると共に、回路基板をその他方面が封口板に対向するように間隙を隔てて配置して樹脂充填対象物を形成し、この樹脂充填対象物を二次電池及び回路基板を所定位置に位置決めして金型内に配置し、二次電池と回路基板との間の樹脂充填空間に樹脂を充填する樹脂成形を行って二次電池と回路基板とを一体化した中間完成品を形成し、この中間完成品の少なくとも外部接続端子を外部露出させて外装被覆を形成する電池パックの製造方法であって、前記金型として、二次電池を収容保持する電池保持部と、回路基板の両端を嵌合保持して回路基板の位置決めを行う左右１対の基板位置決め用溝、二次電池の封口板側の両肩部に当接して二次電池の位置決めを行う左右1対の電池位置決め用壁面、および左右１対の基板位置決め用溝と左右1対の電池位置決め用壁面のそれぞれとを繋ぐ位置決めされた回路基板に直角な方向の側面壁を備えた基板保持部と、前記基板保持部を付勢して、前記電池位置決め用壁面を二次電池の前記両肩部に当接させる付勢手段とを備え、前記電池位置決め用壁面が二次電池の前記両肩部に当接したときに、前記基板位置決め用溝に位置決めされた回路基板と、二次電池の封口板と、前記側面壁とによって囲まれる空間が樹脂充填空間となるように構成された金型を用い、前記樹脂充填対象物を、その回路基板を前記基板位置決め用溝に位置決めし、その二次電池を前記電池保持部に収容保持させ、前記基板保持部を付勢手段で付勢して、前記電池位置決め用壁面を二次電池の前記両肩部に当接させた状態で、前記金型内に配置し、前記樹脂充填空間に樹脂を充填して樹脂成形を行うことによって前記中間完成品を得ることを特徴とするものである。
【００２１】
上記第４Ａ発明、第４Ｂ発明の製造方法によれば、金型内に電池位置決め用壁面と基板位置決め用溝との形成方向を平行に形成して、金型内に回路基板はその縁部が基板位置決め用溝に嵌入するようにして位置決めし、二次電池はその底面側が電池位置決め用壁面に当接するように付勢した場合には、二次電池と回路基板とをその間の間隙に樹脂を充填して一体化するので、回路基板は位置規制され、二次電池の高さ寸法のバラツキは充填された樹脂の高さ寸法の変化によって吸収され、中間完成品の高さ寸法は一定に仕上げられる。この中間完成品の外部接続端子を含む所定部位を外部露出させて外装被覆を形成すると、外部接続端子の位置が精度よく位置決めされ、分解し難く堅牢構造の電池パックに形成できる。また、基板位置決め用壁面に回路基板が当接するように付勢し、電池位置決め用壁面に二次電池の封口板側が当接するように付勢すると、二次電池と回路基板との間の間隙は一定の寸法に位置決めされ、この間隙内に樹脂が充填成形されることにより二次電池と回路基板とが一体化される。このように形成された中間完成品は二次電池の高さ寸法のバラツキにより高さ寸法にバラツキが生じる。この高さ寸法のバラツキは、外装被覆を行う二次成形時に外形寸法が一定になるように樹脂成形するとき、二次電池の底面側の厚さ変化によって吸収される。
【００２２】
また、本願第５発明に係る電池パックの製造方法は、扁平長方形に形成された二次電池の封口板に、一方面に外部接続端子を形成した回路基板を間隙を隔てて配置すると共に、弾性により回路基板を二次電池から離反させる方向に付勢する接続部材により回路基板を二次電池に接続して樹脂対象物を形成し、二次電池の底面から回路基板の外部接続端子の形成面までの寸法を規制した内部空間が形成された金型内に、前記樹脂充填対象物を前記接続部材の付勢に抗して配置し、二次電池と回路基板とを隔てる間隙内に樹脂を充填する樹脂成形を行って二次電池と回路基板とを一体化した中間完成品に形成し、この中間完成品の少なくとも外部接続端子を外部露出させて外装被覆を形成することを特徴とするものである。
【００２３】
上記第５発明の製造方法によれば、回路基板が接続部材により二次電池から離反する方向に付勢された状態の樹脂充填対象物を、二次電池の底面から回路基板の外部接続端子の形成面までの寸法を規制した内部空間が形成された金型内に配置するので、接続部材はその弾性により二次電池と回路基板とを内部空間の対向壁面に押し付けて二次電池の高さ寸法のバラツキを吸収すると同時に回路基板を一定位置に固定して、二次電池の底面から回路基板までの寸法を一定の状態にすることができる。この状態で二次電池と回路基板とに間の間隔内に樹脂を充填すると、二次電池と回路基板とを一体化して二次電池の底面から回路基板の外部接続端子の形成面までの寸法を所定値にした中間完成品に形成することができる。この中間完成品に外装被覆を形成して電池パックに完成させることができる。
【００２４】
上記各製造方法において、二次電池の封口板に回路基板方向にアンダーカット部位を形成することにより、回路基板との間の間隙に充填された樹脂はアンダーカット部位に入り込んで二次電池と強固に接合され、分解し難く堅牢な構造に形成される。
【００２５】
また、外装被覆は、中間完成品に対して、回路基板の外部接続端子形成面から二次電池の封口板上までの間を少なくとも外部接続端子を外部露出させて形成した上部成形部と、二次電池の底面に所定高さに形成した下部成形部と、上部成形部と下部成形部との間を二次電池の短側面でつなぐ連結成形部とを二次成形し、二次電池の側周面と、上部成形部及び下部成形部の側周部の一部と、連結成形部とを被覆してシートを巻着させることにより、厚さ寸法が二次電池にシート厚さを加えた薄型の電池パックに形成することができる。前記連結成形部は、横断面形状が長円形に形成された二次電池の両端の円弧部にそれを囲む矩形線内に入るように形成すると、電池パックの幅寸法を二次電池の幅寸法にシートの厚さを加えて無駄な寸法増加を防ぐことができ、円弧を囲む矩形線内の一方にのみ連結成形部を形成すると電池パックの横断面形状が非対称となり、機器への装填方向を規制すると共に、円弧部分は機器ケースの角部に形成されるアール形状に対応させることができる。
【００２６】
また、外装被覆は、中間完成品に所定高さ寸法に形成された筒状体又は有底筒状体を被せ、回路基板の外部接続端子形成面側及び／又は二次電池の底面側に形成された開口端に、外部接続端子を含む所定部位を外部露出させて樹脂を充填成形すると、開口端に樹脂を充填成形することにより中間完成品の全周面を外部接続端子を含む所定部位を外部露出させて容易に被覆することができる。
【００２７】
また、外装被覆は、中間完成品の全外周面を外部接続端子を含む所定部位を外部露出させて樹脂で被覆するように成形することができ、中間完成品を密閉状態に被覆することができ、耐湿性に優れた電池パックが構成できる。
【００２８】
また、一次成形及び二次成形に用いる金型内の樹脂充填対象物又は中間完成品から外部露出する活電部位と接触する部位には、絶縁性被覆を施すことにより、樹脂充填成形時あるいは外装被覆時に短絡や漏電が発生することが防止できる。
【００２９】
【発明の実施の形態】
以下、添付図面を参照して本発明の実施形態について説明し、本発明の理解に供する。尚、以下に示す実施形態は本発明を具体化した一例であって、本発明の技術的範囲を限定するものではない。
【００３０】
本実施形態は、扁平角形のリチウムイオン二次電池を用いて携帯電話機に適用する電池パックを構成した例を示すものである。携帯電話機に適用する電池パックは、小型、軽量、薄型に加えて高機能化に対応する高エネルギー密度、携帯機器として避けられない落下等による衝撃に耐え得る機械的強度、分解され難い構造、短絡や過充電、高温等から二次電池を保護する安全機能など備えることが要求されており、以下に示す電池パックはこれらの要件を満たすように構成されている。
【００３１】
図１は、実施形態に係る電池パック１の外観を示すもので、一方端面に正極端子及び負極端子、温度検出端子からなる外部接続端子６を外部露出させ、後述するテスト端子３０上に水没シール９を貼着し、扁平な非対称形状に構成されている。図２は、この電池パック１を分解して各構成要素を示したもので、以下に各構成要素の詳細と、各構成要素を用いた電池パック１の製造方法について説明する。
【００３２】
リチウムイオン二次電池（以下、二次電池）２は、図３に示すように、横断面形状が長円形の有底筒状に形成されたアルミニウム製の電池缶２２内に発電要素を収容し、その開口端は封口板２３がレーザー溶接されることによって封口されている。電池缶２２に接合して電池正極となる封口板２３には、その中央に上ガスケット２４ａ及び下ガスケット２４ｂで絶縁して電池負極２５が凸形成されている。また、封口板２３の両側には封口板２３をプレス加工してキノコ状の係合突起（アンダーカット部位）２６、２６が形成されている。尚、２７は電解液注入口を閉じる封栓で、電池缶２２内に電解液を注入した後、電解液注入口は封栓２７によって閉じられ、封栓２７は封口板２３に溶接される。
【００３３】
前記係合突起２６は、封口板２３の所定位置にプレス加工により円筒状の突出部を形成し、これの頭部が周囲に開くようにプレス加工すると、図示するようなキノコ状に形成される。尚、係合突起２６の形成はプレス加工によらず、キノコ状の部材や逆Ｌ字状の部材を封口板上に溶接することによっても形成することができる。
【００３４】
上記二次電池２には、図３（ｃ）に示すように、電池負極２５に温度ヒュ−ズ１０の一方接続片１０ａが溶接される。温度ヒューズ１０の上面には破線で示すように断熱シート１６が貼着され、後述する樹脂充填時に温度ヒューズ１０が溶断することを防止している。温度ヒューズ１０の他方接続片１０ｂは封口板２３上に貼着された絶縁紙２１上に配置され、後述する負極リード板５の一端にスポット溶接により接合される。また、温度ヒューズ１０と二次電池２との間には両者を接合して熱伝導性の接着剤が塗布され、温度ヒューズ１０は二次電池２に熱結合した状態にしている。
【００３５】
二次電池２を過充電や過放電、過電流から保護する保護回路を構成した回路基板３は、その外面側となる一方面に、図４（ａ）に示すように、前記外部接続端子６やテスト端子３０が形成され、二次電池２側となる他方面に、図４（ｂ）に示すように、集積回路部品をはじめとする電子部品３１が実装され、両側に二次電池２に接続するための正極半田付けランド３２、負極半田付けランド３３が形成されている。尚、各図において回路基板３に形成されている回路パターンやスルーホール等の表示は省略している。
【００３６】
図４（ｃ）に示すように、前記正極半田付けランド３２には電子部品３１との間に絶縁紙３４を介した正極リード板（接続部材）４の一端が半田付けされ、負極半田付けランド３３には負極リード板（接続部材）５の一端が半田付けされる。
【００３７】
この接続加工を終えた回路基板３は、図５（ａ）に示すように、二次電池２に対し、正極リード板３２の他端は封口板２３の板面に、負極リード板３３の他端は前記温度ヒューズ１０の他方接続片１０ｂ上に、それぞれスポット溶接される。この接続状態では、回路基板３は封口板２３の板面に対して直交する方向になっているので、図５（ｂ）に示すように、正極及び負極の各リード板４、５を折り曲げ、回路基板３の板面と封口板２３の板面との間に間隙を設け、略並行になる状態に整形する。このように二次電池２に回路基板３を接続して、図１１（ａ）に示すような樹脂充填対象物７が形成される。
【００３８】
上記樹脂充填対象物７の二次電池２と回路基板３との間の間隙に樹脂を充填成形して二次電池２と回路基板３とを一体化する。このとき、二次電池２の底面から回路基板３の外部接続端子６の形成面までの高さＨが所定寸法になるように樹脂成形することが重要で、それを実現する第１〜第４の製造方法について以下に説明する。
（第１の製造方法）
図６（ａ）に示すように、一次モールド金型３５の下型３６は、可動部４１が付勢手段４５によって固定部４２側に移動可能に構成され、可動部４１には真空吸着部４３が設けられている。前記可動部４１を後退させた状態にして下型３６内に樹脂充填対象物７（図６では二次電池２と回路基板３のみを表示）を配置し、可動部４１を前進させると二次電池２はその底面が固定部４２の内壁面に押し付けられて位置決めされる。一方、回路基板３は真空吸着部４３からの真空吸引により真空吸着部４３の壁面に密着して位置決めされる。
【００３９】
前記二次電池２の底面から回路基板３の外部接続端子６の形成面までの高さ寸法Ｈは、二次電池２の高さ寸法ｈのバラツキ及び回路基板３が一定位置に固定されていないことが原因で変動するが、回路基板３は真空吸引によって一定位置に固定され、可動部４１は二次電池２の高さ寸法ｈに応じて、その前進量が変化するので、下型３６内に位置決めされた二次電池２と回路基板３とは、それらの間の間隙の高さ寸法Ｇの変化により、二次電池２の底面から回路基板３の外部接続端子６の形成面までの高さ寸法Ｈは一定の状態になる。
【００４０】
樹脂充填対象物７に対して樹脂充填成形するときの二次電池２と回路基板３との位置決めは、一次モールド金型３５の下型３６ａを図６（ｂ）に示すように構成することもできる。回路基板３は真空吸着により基板位置決め用壁面７５に密着し、二次電池２は押圧軸８５が付勢手段７６によって付勢されることにより電池位置決め用壁面７７に両肩部分が当接する。この構成では、二次電池２と回路基板３との間隔Ｇは一定に位置決めされ、二次電池２の高さ寸法ｈのバラツキは二次電池２の底面から回路基板３の外部接続端子６の形成面までの高さ寸法Ｈ４の変動となるが、この高さ寸法Ｈ４の変動は後述する二次モールドによって吸収される。
【００４１】
上記のように二次電池２と回路基板３とを位置決めした下型３６、３６ａ上に、図７に示す上型３７を下降させ、上型３７に設けられたゲート４４から二次電池２と回路基板３との間の間隙に樹脂を注入する。注入された樹脂は、図８に示すように、回路基板３に実装された電子部品３１や正極及び負極の各リード板４、５の周囲にも回り込んで回路基板３に接合し、二次電池２の封口板２３上に形成された係合突起２６のアンダーカット部分にも回り込んで封口板２３に接合した一次モールド体１１に成形される。樹脂は電子部品３１や二次電池３、あるいは温度ヒューズ１０に悪影響を与えない程度の温度で流動化し、温度低下により硬化するホットメルトが好適である。
【００４２】
樹脂の温度が比較的低くても２００℃を越える温度であるため、溶断温度が１０４℃に設定されている温度ヒューズ１０に触れると、温度ヒューズ１０は溶断して電池パック１自体の機能を停止させてしまうことになる。その対策は、断熱シートにより温度ヒューズ１０と樹脂との間を熱的に遮蔽する方法や樹脂と直接触れない位置に温度ヒューズ１０を配設する方法などを別途発明により提案しているが、ここでは、前述したように温度ヒューズ１０上に断熱シート１６を貼着して、樹脂の熱が温度ヒューズ１０に伝熱することを抑えている。また、一次モールド金型３５の温度ヒューズ１０の配設位置に対応する部位を熱伝導性のよい材質（例えば、アルミニウム）で形成し、樹脂の熱を金型側に放散させ、温度ヒューズ１０への熱伝導を抑制することによっても解決することができる。
【００４３】
樹脂充填対象物７は二次電池２の正極、負極に接続された活電部分が外部露出しているため、一次モールド金型３５内に収容されたときに短絡や漏電が発生しないように、一次モールド金型３５の露出した活電部分が接触する恐れのある部位には、アルミナ処理あるいはフッ素樹脂処理による絶縁被覆が施されている。また、金型をアルミニウムで形成し、所要部位をアルマイト処理することにより前記絶縁被覆が形成されると同時に、熱伝導性の向上により温度ヒューズ１０に対する充填樹脂による熱影響が抑制される。
【００４４】
充填された樹脂を硬化させた後、上型３７を上昇させ、真空吸引を解除し、可動部４１又は付勢手段７６を後退させると、図８に示すように二次電池２と回路基板３とが樹脂の硬化により形成された一次モールド体１１により一体化され、図１１（ｂ）に示すような中間完成品８として下型３６から取り出すことができる。この中間完成品８の周囲に外装被覆を施すことによって電池パック１に形成することができる。
【００４５】
ここでは、外装被覆は、二次モールディングと巻着シートの貼着によって施される。二次モールディングを実施する前に、二次電池２の底面にインシュレータ１４を貼着する。
【００４６】
二次モールディングは、図９に示すように、二次モールド金型４６に前記中間完成品８を配置して、中間完成品８の所要部位に樹脂を成形する。二次モールド金型４６の下型４７には中間完成品８を収容する凹部５０が形成されており、凹部５０の一側壁面には内方に進出付勢される３個の外部接続端子用突起５１とテスト端子用突起５２とが設けられ、対向する他側壁面には内方に進出付勢される底面用突起５４が設けられている。凹部５０内に中間完成品８を配置し、前記外部接続端子用突起５１及びテスト端子用突起５２、底面用突起５４を進出させると、外部接続端子用突起５１は回路基板３上に形成された３か所の外部接続端子６に圧接し、テスト端子用突起５２はテスト端子３０に圧接し、底面用突起５４は二次電池２に底面に貼着されたインシュレータ１４に圧接する。
【００４７】
中間完成品８を収容した下型４７上を上型４８で閉じ、上型４８に設けられたゲート５３から二次モールド金型４６内に樹脂を充填する。樹脂は４か所から二次モールド金型４６内に射出され、図１０に示すように、中間完成品８の外部接続端子６及びテスト端子３０を外部露出させて回路基板３及び一次モールド体１１を被覆し、図１１（ｃ）に示すように二次電池２の封口板２３上に固着した上部成形部１７を形成すると共に、二次電池２の底面にインシュレータ１４の周囲を包み込んで所定厚さに固着した下部成形部１８を形成し、更に前記上部成形部１７と下部成形部１８とを二次電池の側面コーナーで連結する連結成形部１９が形成される。前記連結成形部１９は、図１２に示すように、横断面形状が長円形の二次電池２の円弧側面の一方側９０度部位が直角に形成されるように樹脂が成形される。前記上部成形部１７及び下部成形部１８、連結成形部１９によって、図２に示すした二次モールド体１２が形成される。
【００４８】
尚、図６（ｂ）に示した下型３６ａを用いて樹脂充填成形された中間完成品８の場合は、前述したように二次電池２の高さ寸法ｈのバラツキにより中間完成品８の高さ寸法Ｈ４が変動するが、二次モールド体１２が一定の高さ寸法に成形されることによって高さ寸法Ｈ４の変動は吸収される。
【００４９】
また、中間完成品８においても外部接続端子６などの二次電池２の正極、負極に接続された活電部分が外部露出しているため、一次モールド金型３５と同様に二次モールド金型４６においても中間完成品８に短絡や漏電が発生しないように、二次モールド金型４６の露出した活電部分が接触する恐れのある部位、即ち外部接続端子６やテスト端子３０などに当接する外部接続端子用突起５１及びテスト端子用突起５２には、アルミナ処理あるいはフッ素樹脂処理による絶縁被覆が施されている。
【００５０】
前記上部成形部１７の周面の二次電池寄りには段差部３８が形成されており、これを貼着位置決め線として、二次電池２の側周面を巻回して巻着シート２０が巻着される。この後、テスト端子３０を用いて動作状態が検査され、検査合格品にはテスト端子３０周囲の凹部内に水没シール９が貼着され、図１に示したような電池パック１に形成される。
【００５１】
このように形成された電池パック１は、図１に示すように、扁平な一方面の両肩部分が二次電池２の両側面の円弧が表面に現れる円弧コーナーに形成され、他方面の両肩部分が連結成形部１９によって角形コーナーに形成されるので、外部接続端子６が非対称位置に形成されていることと相まって機器への逆装填が防止できる。また、円弧コーナーは機器ケースの角部のアール形状に対応し、無駄な空間が形成されることなく機器への収納が可能となる。
【００５２】
また、二次電池２の底面に貼着されたインシュレータ１４の中央部位には前記下型４７の底面用突起５４が当接して樹脂が成形されないので、中間完成品８の底面側には、図１３に示すように凹部３９が形成される。前述のように電池パック１は機器の狭い電池パック収容空間に装填されるので、電池パックを収容空間から取り出すときに手がかりになるものがないと取り出しが困難であるが、前記凹部３９が形成されていることによって電池パック１の底面に爪先を掛けることができ、凹部３９は所謂ネイルフックとなって電池パック１の取りだしを容易にする。
（第２の製造方法）
本第２の製造方法は、前述の樹脂充填対象物７に樹脂充填して一次モールド体１１を成形する方法を異にするものである。以下、第１の製造方法と共通する構成要素には同一の符号を付し、同一の製造方法の説明は省略して、第２の製造方法について説明する。
【００５３】
図１１（ａ）に示したように形成された樹脂充填対象物７は、図１４（ａ）に示す一次モールド金型の下型５６内に配置される。回路基板３は下型５６の一方壁面に設けられた押圧軸５７が付勢手段５９によって押し出されることにより基板位置決め壁面６０に両端部が当接して位置決めされる。また、二次電池は下型５６の他方壁面に設けられた押圧軸５８が付勢手段６２によって押し出されることによって電池位置決め用壁面６１に封口板２３の両端部が当接して位置決めされる。この位置決めにより、回路基板３が一定位置にない状態は、二次電池２の底面から回路基板３の外部接続端子６形成面までの高さ寸法Ｈ２に規制される。このように二次電池２と回路基板３とが位置決めされた下型５６上に上型（図示せず）を下降させ、二次電池２と回路基板３との間に一定間隔に形成された間隙Ｇ２に樹脂が充填され、二次電池２と回路基板３とを充填された樹脂が硬化した一次モールド体１１により一体化した中間完成品８に形成される。
【００５４】
上記一次モールディングによって形成された中間完成品８は、二次電池２の高さ寸法ｈのバラツキによって全体の高さ寸法Ｈ２が変動する。この高さ寸法Ｈ２の変動は、図９に示した二次モールド金型４６による二次モールディング時に、二次電池２の底面に成形される下部成形部１８の厚さが変化することによって吸収され、一定高さ寸法の電池パック１に形成される。この外装被覆の形成方法は、上記第１の製造方法によるものと同様なので、その説明は省略する。
【００５５】
上記下型５６を用いた二次電池２の位置決めにおいて、二次電池２の高さ寸法ｈのバラツキによる中間完成品８の高さ寸法Ｈ２の変動は、図１４（ｂ）に示すように構成された下型５６ａを用いることによって一定の高さ寸法Ｈ５の中間完成品８に形成することが可能である。
【００５６】
図１４（ｂ）において、二次電池２は電池付勢手段８１によって付勢されることにより下型５６ａの電池位置決め用壁面８３に当接して位置決めされ、回路基板３は基板付勢手段８０によって付勢されることにより下型５６ａに形成された基板位置決め用壁面８２に当接して位置決めされる。この下型５６ａの構成により、回路基板３は一定位置に位置決めされ、二次電池２の高さ寸法ｈのバラツキは二次電池２と回路基板３との間の間隙Ｇ５の変化によって吸収され、一定高さ寸法Ｈ５の中間完成品８として完成される。
（第３の製造方法）
本第３の製造方法は、前述の樹脂充填対象物７に対する樹脂充填の方法を異にするもので、以下、第１及び第２の各製造方法と共通する構成要素には同一の符号を付し、同一製造方法の説明は省略して、第３の製造方法について説明する。
【００５７】
本第３の製造方法においては、図１５に示すように、回路基板３を二次電池２に接続する正極リード板４ａ及び負極リード板５ａを折り曲げに対して弾性を有する材料によって形成する。この正極リード板４ａ及び負極リード板５ａの一端側を回路基板３に半田付けした後、図５（ａ）に示したように二次電池２に他端をスポット溶接して、図５（ｂ）に示したように、回路基板３が二次電池３の封口板２３と略並行になるように折り曲げたとき、正極リード板４ａ及び負極リード板５ａが折り曲げに対して弾性を有しているため封口板２３と並行にならず、図１５に示すように、回路基板３は傾斜した角度になって二次電池２に接続された状態になった樹脂充填対象物７が形成される。
【００５８】
この樹脂充填対象物７を、図１６に示すように、回路基板３の外部接続端子６形成面と二次電池２の底面との間の寸法Ｈ３が規制された一次モールド金型の下型６４内に配置する。このとき、回路基板３は二次電池２の封口板２３と並行になっていないため下型６４内に圧入されることになるが、圧入されると高さ寸法Ｈ３が規制された下型６４の壁面に密着して封口板２３と並行した状態に収まると同時に、正極リード板４及び負極リード板５の弾性による付勢によって二次電池２は対向壁面に押し付けられる。このように樹脂充填対象物７を下型６４内に収容することによって、二次電池２の高さ寸法ｈのバラツキや回路基板３が一定位置にない状態を正極リード板４及び負極リード板５の曲げ弾性によって吸収して、回路基板３の外部接続端子６の形成面と二次電池２の底面との間の寸法Ｈ３を一定に規制した状態が得られる。
【００５９】
上記のように樹脂充填対象物７を収容した下型６４上に上型（図示せず）を下降させ、二次電池２と回路基板３との間の間隙Ｇに樹脂を充填すると、二次電池２と回路基板３とは充填された樹脂によって一体に固定され、図１１（ｂ）に示すような中間完成品８に形成される。
【００６０】
この中間完成品８に対する外装被覆の形成は、第１及び第２の各製造方法と同様に実施することができるので、その説明は省略する。
（第４の製造方法）
本第４の製造方法は、前述の樹脂充填対象物７に樹脂充填して一次モールド体１１を成形する方法を異にするものである。以下、第１及び第２の製造方法と共通する構成要素には同一の符号を付し、同一の製造方法の説明は省略して、第３の製造方法について説明する。
【００６１】
図１１（ａ）に示したように形成された樹脂充填対象物７は、図１７（ａ）に示す一次
モールド金型の下型９１内に配置される。回路基板３は下型９１に形成された基板位置決め用溝９２に両端部を嵌入させることにより位置決めされる。また、二次電池は下型９１に設けられた付勢手段９４によって押し出されることによって電池位置決め用壁面９３に封口板２３の両端部が当接して位置決めされる。この位置決めにより回路基板３が一定位置にない状態は、二次電池２の底面から回路基板３の外部接続端子６形成面までの高さ寸法Ｈ６に規制される。このように二次電池２と回路基板３とが位置決めされた下型５６上に上型（図示せず）を下降させ、二次電池２と回路基板３との間に一定間隔に形成された間隙Ｇ６に樹脂が充填され、二次電池２と回路基板３とを充填された樹脂が硬化した一次モールド体１１により一体化した中間完成品８に形成される。
【００６２】
上記一次モールディングによって形成された中間完成品８は、二次電池２の高さ寸法ｈのバラツキによって全体の高さ寸法Ｈ２が変動する。この高さ寸法Ｈ２の変動は、図９に示した二次モールド金型４６による二次モールディング時に、二次電池２の底面に成形される下部成形部１８の厚さが変化することによって吸収され、一定高さ寸法の電池パック１に形成される。この外装被覆の形成方法は、上記第１の製造方法によるものと同様なので、その説明は省略する。
【００６３】
上記下型９１を用いた二次電池２の位置決めにおいて、二次電池２の高さ寸法ｈのバラツキによる中間完成品８の高さ寸法Ｈ６の変動は、図１７（ｂ）に示すように構成された下型９１ａを用いることによって一定の高さ寸法Ｈ７の中間完成品８に形成することが可能である。
【００６４】
図１７（ｂ）において、二次電池２は電池付勢手段９７によって付勢されることにより下型９１ａの電池位置決め用壁面９６に当接して位置決めされ、回路基板３は基板位置決め用溝９５に両端部が嵌入して位置決めされる。この下型９１ａの構成により、回路基板３は一定位置に位置決めされ、二次電池２の高さ寸法ｈのバラツキは二次電池２と回路基板３との間の間隙Ｇ７の変化によって吸収され、一定高さ寸法Ｈ７の中間完成品８として完成される。
【００６５】
上記第１〜第４の各製造方法によって製造された電池パック１について、落下高さ１．５ｍでコンクリート上に６面各２サイクル落下させる自由落下試験、落下高さ１．０ｍで鉄板上に５０回落下させて機械的性能を見て、２００回落下させて電気特性を見るランダム落下試験を実施し、更に−４０℃から８０℃の温度変化を複数回加えるヒートショック試験、３方向の振動を加える振動試験、外部接続端子に荷重を加える端子強度試験を実施した。この試験後の電池パック１を機器に装着し、装着の異常がないか、正常に作動するか、変形や緩みがないかなどについて検証した。この結果、各試験後にも障害の発生は見られず、堅牢な構造であることが立証された。
【００６６】
また、２００℃を越える温度の樹脂を充填成形することによる二次電池２への影響、あるいは樹脂充填部位に配設された温度ヒューズ１０の損傷について検証したが、異常発生はなかった。
【００６７】
また、完成した電池パック１を分解した場合の状態を検証するために、故意に分解を試みたところ、分解は一般的なパックケースを用いた構造に比して極めて困難であることが明らかであり、一次モールド体１１を破壊すると封口板２３の両端に設けられた係合突起２６が破壊され、充填成形された中に存在する正極及び負極のリード板４、５や接続部分が破壊されて、分解されたことが容易に判断できる状態となった。
【００６８】
また、仕上がり外形寸法の精度は、各部の寸法が±０．１〜０．２ｍｍの誤差範囲に収まり、特に精度が要求される底面から外部接続端子６までの寸法も同誤差内であり、機器との接続に支障がない状態になることが確認された。
【００６９】
以上説明した構成において、中間完成品８に対する外装被覆は、所要部位に樹脂成形した二次モールド体１２と巻着シート１３とによって形成しているが、これに限定されるものでなく、図１８（ａ）に示すような筒状の外装ケース７１に中間完成品８を挿入し、下方の開口部を樹脂充填により封口し、上方の開口部に外部接続端子６及びテスト端子３０が外部露出するように樹脂充填すると、外形は電池パック１と同様に構成することができる。
【００７０】
また、図１８（ｂ）に示すように、外部接続端子６及びテスト端子３０に対応する位置に開口部を形成した有底筒状の外装ケース７２に中間完成品８を挿入し、下方の開口部に樹脂充填して封口することによっても電池パック１と同様の外形形状に構成することができる。前記外装ケース７２は下方開放の有底筒状体であるが、上方を開放した有底筒状に形成して、上部開口部に外部接続端子６及びテスト端子３０が外部露出するように樹脂充填しても外形は電池パック１と同様に構成することができる。
【００７１】
また、中間完成品８の外周面に外部接続端子６及びテスト端子３０が外部露出するようにして樹脂成形することによっても、図１に示したような電池パック１に構成することができる。
【００７２】
【発明の効果】
以上の説明の通り本発明によれば、底面からその対向面にある外部接続端子までの寸法を一定にして、二次電池と回路基板とを樹脂モールディングにより一体化した電池パックを構成することができ、小型の携帯電子機器に適した電池電源として接続の確実性や落下等の衝撃に耐え得る堅牢性を備えた電池パックを提供することができる。
【図面の簡単な説明】
【図１】実施形態に係る電池パックの外観を示す斜視図。
【図２】同上電池パックの各構成要素を示す分解斜視図。
【図３】二次電池の構成を示す（ａ）は平面図、（ｂ）は封口板側の断面図、（ｃ）は温度ヒューズを取り付けた状態での平面図。
【図４】回路基板の構成を（ａ）は外面側、（ｂ）は内面側、（ｃ）はリード板取付け状態でそれぞれ示す斜視図。
【図５】回路基板の二次電池への取付け状態を示す斜視図。
【図６】第１の製造方法による樹脂充填を説明する模式図。
【図７】同上一次モールド金型の構成を示す斜視図。
【図８】一次モールド体を形成した状態を示す断面図。
【図９】二次モールド金型の構成を示す斜視図。
【図１０】二次モールド体を形成した状態を示す断面図。
【図１１】製造工程の各段階での形成状態を順に示す斜視図。
【図１２】連結成形部の形成位置を説明する断面図。
【図１３】中間完成品の底面に形成された凹部を示す斜視図。
【図１４】第２の製造方法による樹脂充填を説明する模式図。
【図１５】第３の製造方法による二次電池への回路基板の接続状態を示す斜視図。
【図１６】第３の製造方法による樹脂充填を説明する模式図。
【図１７】第４の製造方法による樹脂充填を説明する模式図。
【図１８】外装被覆の別態様を示す外装ケースの構成を示す斜視図。
【図１９】電池パックの外部接続端子の形成位置の精度を説明する模式図。
【符号の説明】
１電池パック
２二次電池
３回路基板
４正極リード板（接続部材）
５負極リード板（接続部材）
６外部接続端子
７樹脂充填対象物
８中間完成品
１０温度ヒューズ
１１一次モールド体
１２二次モールド体
１３巻着シート
１６断熱シート
１７上部成形部
１８下部成形部
１９連結成形部
２３封口板
２６係合突起（アンダーカット部位）
３５一次モールド金型
３６、４７、５６、６４下型
４１可動部
４２固定部
４３真空吸着部
４５、５９、６２付勢手段
４６二次モールド金型
５１外部接続端子用突起
５７、５８押圧軸
６０、７５、８２基板位置決め用壁面
６１、７７、８３電池位置決め用壁面
９２、９５基板位置決め用溝[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a method of manufacturing a battery pack in which constituent elements are integrated by resin filling so as to be suitable for a battery power source of a small portable electronic device or the like, and the size and robustness are improved.
[0002]
[Prior art]
  Mobile electronic devices such as mobile phones and PDAs are becoming smaller and thinner, and more advanced in functionality, and accordingly, a battery serving as a power source is required to be smaller, thinner and have higher capacity. Lithium ion secondary batteries are effective as compact and high capacity batteries, and flat rectangular ones are suitable for thinning devices, and can be used repeatedly as portable batteries for portable electronic devices. Application is increasing.
[0003]
  Since the lithium ion secondary battery has a high energy density and uses a flammable organic solvent as an electrolytic solution, consideration for safety is important. It is necessary to ensure safety so as not to damage the human body and equipment even when an abnormality occurs for some reason. For example, when a short circuit occurs between the positive electrode terminal and the negative electrode terminal of the battery for some reason, an excessive short circuit current flows in a battery with high energy density, Joule heat is generated due to internal resistance, and the battery temperature rises. When the battery temperature rises, the reaction between the positive electrode plate active material and the electrolyte solution, the evaporation and decomposition of the electrolyte solution, and the like, the gas pressure inside the battery increases rapidly, and the battery may burst or ignite. The cause of the battery becoming hot is not only the above external short circuit, but also when the secondary battery is overcharged, or when the portable electronic device loaded with the battery is placed near the heater or left in a car parked under hot weather And so on.
[0004]
  There are various causes such as electrical, mechanical, thermal, etc. that can cause the battery to fall into an abnormal state. In non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries, the battery falls into an abnormal state. And a function for preventing a dangerous state even when an abnormal state occurs. As a function of the battery itself, the active material of the electrode plate and the electrolytic solution have been devised so as not to cause an excessive reaction, and the polyolefin microporous membrane used as a separator softens and closes the pores at an abnormally high temperature. There is a shutdown function. In addition, the cylindrical lithium ion secondary battery is provided with a protective function for limiting excessive current due to an external short circuit by providing a PTC (Positive Thermal Coefficient) element connected in series with the input / output circuit in the sealing portion. Yes. In a battery in which the PTC element is not provided in the battery, it is essential to provide a PTC element and a thermal fuse as external circuit components, and to provide a battery protection circuit that protects the battery from overcharge and overdischarge. Generally, these components are housed in a pack case together with a secondary battery and configured in the form of a battery pack.
[0005]
  However, the resin molding die for forming the pack case is expensive to manufacture and has a long development period, so that it cannot be applied to portable electronic devices with a short introduction period of new models. In addition, as described above, in order to configure a battery pack corresponding to miniaturization and thinning of a portable electronic device, there is a limit to the wall thickness that can be molded by resin molding, and there is a limit to an exterior case by resin molding.
[0006]
  Also, in order to ensure safety, it is necessary to disassemble the battery pack so that it is difficult to disassemble the battery pack and prevent it from being used in an incorrect or interesting manner. Is important. In consideration of application to portable electronic devices, a robust structure capable of withstanding impact and vibration due to dropping and the like and moisture resistance of electronic circuit parts are required. In order to realize such a robust and moisture-resistant structure that is difficult to disassemble, it has been envisaged that a circuit board constituting a battery protection circuit or the like and a battery are integrated by resin molding.
[0007]
  The battery pack by the above resin molding has been proposed by the applicant of this application as Japanese Patent Application No. 2000-320166 and Japanese Patent Application No. 2000-363518, and an intermediate finished product in which a battery and a circuit board are connected by a connecting member is placed in a mold. The secondary battery and the circuit board are integrated by filling the resin around the intermediate finished product so that the external connection terminals formed on the circuit board are exposed to the outside.
[0008]
  Moreover, in what was disclosed by Unexamined-Japanese-Patent No. 2000-315483, what connected the battery and the circuit board by the connection member is arrange | positioned in a metal mold | die, the circuit board is resin-sealed, and on a battery or a pack case (battery A structure for fixing to a lid) or a structure for resin-sealing a circuit board and a battery is disclosed.
[0009]
[Problems to be solved by the invention]
  In the configuration disclosed in the above Japanese Patent Laid-Open No. 2000-315483, a connector is provided at the tip of a lead wire drawn out from a resin-sealed circuit board. Made by fitting between male and female. This external connection structure is not a problem when the battery housing space has a margin in a relatively large device, but it is a matter of course that the battery housing space has a small margin in a small device whose main purpose is the battery pack of the present invention. Therefore, it is difficult to apply this connection structure. In the connection structure of the battery pack of the present invention with the device side, when the battery pack is stored in the battery storage space on the device side, the device side contact terminal (probe) provided there is exposed to the outside at a predetermined position of the battery pack. It is designed to be in pressure contact with the external connection terminal.
[0010]
  The circuit board on which the external connection terminal is formed and the battery are resin molded to form a battery pack, and the device side connection terminal provided in the battery storage space on the device side and the external connection terminal are pressed into a state where the contact resistance is low. In order to achieve this, it is necessary to form the outer dimensions of the battery pack and the positions of the external connection terminals with high accuracy. In the case of connection by such contact, if the formation accuracy is low, the contact resistance between the device side connection terminal and the external connection terminal becomes large, resulting in abnormalities such as contact failure and voltage drop.
[0011]
  In particular, in the configuration in which external connection terminals are formed on the circuit board and this circuit board is disposed at a position parallel to the battery sealing plate, as shown in FIG. The dimension L up to the formation surface of the connection terminal 103 needs to be finished with high accuracy. However, the height h of the battery 101 varies, and the circuit board 102 is simply connected to the battery 101 by the connecting member 104, and its position and angle are likely to change. In the configuration of the battery pack that is generally adopted, since the battery 101 and the circuit board 102 are positioned and fixed to the pack case, the dimension L can be regulated. In the configuration in which the battery 101 and the circuit board 102 are integrated by resin molding, it is necessary to absorb the variation in the height dimension h of the battery 101, position the circuit board 102, and perform resin molding.
[0012]
  Conventionally, when a battery pack is formed by resin molding, it is difficult to accurately shape the height of the battery pack. Therefore, a biasing means such as a spring is provided in the connection structure using the connector and the battery housing space of the device. The installed battery pack is urged toward the connection terminal of the device to absorb the dimensional variation, and the external connection terminal is exposed at the end of the long side surface of the battery pack. When the pack is inserted, a structure has been adopted in which the device-side connection terminal having an elastic structure is in sliding contact with the external connection terminal, thereby eliminating the contact failure. However, these structures increase the storage space for the battery pack on the device side, increase the number of members for connecting the battery pack, and impair the downsizing of the device. This is a structure that is difficult to apply to electronic devices.
[0013]
  An object of the present invention is to provide a battery pack manufacturing method in which when a battery and a circuit board are integrated by resin molding to form a battery pack, the outer dimensions and the positions of external connection terminals are accurately finished. It is to provide.
[0014]
[Means for Solving the Problems]
  In order to achieve the above object, a battery pack manufacturing method according to the first invention of the present application includes a circuit board having an external connection terminal formed on one surface by a connection member.Formed in a flat rectangleSecondary batterySealing plateThe other side of the circuit board faces the sealing plateBetweenResin-filled object with a gapTheThe resin-filled object is formed by positioning the secondary battery and the circuit board at a predetermined position and placing them in a mold, and performing resin molding to fill the gap between the secondary battery and the circuit board with resin. Intermediate finished product integrating secondary battery and circuit boardTheAnd forming an exterior coating by exposing at least external connection terminals of the intermediate finished product to the outside.
[0015]
  According to the manufacturing method of the first aspect of the invention, the resin-filled object in which the circuit board is connected to the secondary battery is stored by positioning the circuit board and the secondary battery at predetermined positions in the mold. When the resin is filled in the space between the circuit board, the secondary battery and the circuit board are integrated, and the intermediate finish is completed with the dimension from the bottom surface of the secondary battery to the formation surface of the external connection terminal of the circuit board being a predetermined value Can be formed into a product. When an exterior covering is formed on the intermediate finished product, a battery pack having a robust structure that is difficult to disassemble can be formed.
[0016]
  In addition, this application2A inventionThe battery pack manufacturing method according toConnect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering In this method, the mold is in contact with a battery holding portion for holding and holding a secondary battery, a wall surface for positioning the substrate by vacuum suction, and both shoulders on the sealing plate side of the secondary battery. Repositioning the secondary battery A pair of left and right battery positioning walls and a side wall in a direction perpendicular to the positioned circuit board surface connecting each of the board positioning wall and the pair of left and right battery positioning walls, and A substrate holding portion that is movable in a direction of contact with the sealing plate of the secondary battery, and a biasing means that biases the substrate holding portion so that the battery positioning wall faces the shoulders of the secondary battery. A circuit board positioned on the substrate positioning wall surface when the battery positioning wall surface is in contact with both shoulders of the secondary battery, a sealing plate of the secondary battery, and the side wall. Using a mold configured so that the enclosed space is a resin-filled space, the resin-filled object is positioned by vacuum-adsorbing the circuit board to the substrate positioning wall surface, and the secondary battery is the battery. Hold and hold in holding part The substrate holding portion is urged by urging means, and the battery positioning wall surface is placed in contact with the shoulder portions of the secondary battery, and is disposed in the mold, and is placed in the resin-filled space. The intermediate finished product is obtained by filling the resin and molding the resin.It is characterized by this.
  In the battery pack manufacturing method according to the second invention of the present application, a circuit board having external connection terminals formed on one side thereof is connected to a sealing plate of a secondary battery formed in a flat rectangular shape by a connecting member, and the circuit board is connected to other directions. The resin-filled object is formed with a gap so as to face the sealing plate, and the resin-filled object is placed in a mold with the secondary battery and the circuit board positioned at predetermined positions. The resin filling space between the secondary battery and the circuit board is molded with resin to form an intermediate finished product that integrates the secondary battery and the circuit board, and at least the external connection terminals of the intermediate finished product are provided. A method of manufacturing a battery pack that is externally exposed to form an exterior covering, wherein the mold is a battery holding portion that holds and holds a secondary battery movably in a direction away from the circuit board, and the circuit board is vacuumed Positioning by adsorption The substrate positioning wall to be held, the left and right battery positioning walls that contact the shoulders on the sealing plate side of the secondary battery to position the secondary battery, and the left and right battery positioning to the substrate positioning wall A substrate holding part having a side wall in a direction perpendicular to the positioned circuit board surface that connects each of the wall surfaces for driving, and energizing the secondary battery to position the both shoulders of the secondary battery to the battery positioning A circuit board that is positioned and held on the wall surface for positioning the substrate when the shoulder portions of the secondary battery contact the wall surface for positioning the battery. Using a mold configured so that the space surrounded by the battery sealing plate and the side wall becomes a resin-filled space, the circuit board is vacuum-adsorbed on the substrate-positioning wall surface of the resin-filled object. Position the secondary battery Is held in the battery holding portion, the secondary battery is urged by the urging means, and the shoulders of the secondary battery are brought into contact with the battery positioning wall surface in the mold. The intermediate finished product is obtained by arranging and performing resin molding by filling the resin filling space with resin.
[0017]
  the above2A invention, 2B inventionAccording to this manufacturing method, the secondary battery is biased so that the bottom surface side of the secondary battery abuts against the battery positioning wall surface, and the circuit board is vacuum-adsorbed to the substrate positioning wall surface. When the gap is filled with resin and integrated, the variation in the height dimension of the secondary battery and the variation in the position of the circuit board in a position unregulated state are absorbed by the change in the height dimension of the filled resin, The height of the intermediate finished product is finished constant. When an exterior covering is formed by exposing a predetermined portion including the external connection terminal of the intermediate finished product to the outside, the position of the external connection terminal is accurately positioned and can be formed into a robust battery pack that is difficult to disassemble. Also, the secondary battery sealing plate side is urged so as to abut against the battery positioning wall surface, and the circuit board is vacuum-adsorbed to the substrate positioning wall surface, and the secondary battery and the circuit board are placed in a gap between them. When the battery is integrated, the secondary battery and the circuit board are combined with a resin at a constant interval. The variation in the height dimension of the secondary battery is a change in the height dimension of the intermediate finished product, but when resin molding is performed so that the outer dimensions are constant during the secondary molding for exterior coating, the bottom side of the secondary battery It is absorbed by the thickness change.
[0018]
  In addition, this application3A inventionThe battery pack manufacturing method according toConnect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering The method includes a battery holding portion for accommodating and holding a secondary battery as the mold, and a pair of left and right substrate positioning wall surfaces for positioning the circuit board by contacting both ends of the secondary battery facing surface of the circuit board. The circuit board at both ends Biasing means for urging to abut against the substrate positioning wall surface, a pair of left and right battery positioning wall surfaces that abut on both shoulders on the sealing plate side of the secondary battery to position the secondary battery, and left and right A substrate holding portion having a side wall perpendicular to the positioned circuit board connecting the pair of substrate positioning wall surfaces and the left and right pair of battery positioning wall surfaces; and urging the substrate holding portion. Urging means for bringing the battery positioning wall surfaces into contact with the shoulder portions of the secondary battery, and the substrate positioning when the battery positioning wall surfaces are in contact with the shoulder portions of the secondary battery. Using a mold configured such that the space surrounded by the circuit board positioned on the wall surface for the battery, the sealing plate of the secondary battery, and the side wall is a resin-filled space, the resin-filled object is The circuit board is urged by the urging means to Positioning on the wall surface for plate positioning, the secondary battery is accommodated and held in the battery holding portion, the substrate holding portion is urged by the urging means, and the battery positioning wall surfaces are placed on the shoulder portions of the secondary battery. The intermediate finished product is obtained by placing in the mold in a state of being in contact with the resin, filling the resin filling space with resin, and performing resin molding.It is characterized by this.
  In the manufacturing method of the battery pack according to the third invention of the present application, the circuit board having the external connection terminal formed on one side thereof is connected to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and the circuit board is directed to the other direction. The resin-filled object is formed with a gap so as to face the sealing plate, and the resin-filled object is placed in a mold with the secondary battery and the circuit board positioned at predetermined positions. The resin filling space between the secondary battery and the circuit board is molded with resin to form an intermediate finished product that integrates the secondary battery and the circuit board, and at least the external connection terminals of the intermediate finished product are provided. A method of manufacturing a battery pack that is externally exposed to form an exterior coating, wherein the mold includes a battery holding unit that accommodates and holds a secondary battery so as to be movable away from and in contact with the circuit board, and two circuit boards. Both ends of the secondary battery facing surface A pair of left and right board positioning wall surfaces for positioning the circuit board by abutting, a biasing means for biasing the circuit board so that both ends abut against the board positioning wall surface, and both on the sealing plate side of the secondary battery A pair of left and right battery positioning walls that contact the shoulder to position the secondary battery, and a positioned circuit board that connects each of the left and right pair of substrate positioning walls and the left and right pair of battery positioning walls A substrate holding portion having a side wall in a direction perpendicular to the surface, and a biasing means for biasing the secondary battery so that the shoulder portions of the secondary battery abut against the wall surface for battery positioning, When both shoulder portions of the secondary battery abut on the battery positioning wall surface, the circuit board is positioned and held on the substrate positioning wall surface, the secondary battery sealing plate, and the side wall. The space is a resin-filled space. Using the formed mold, the resin-filled object is positioned on the substrate positioning wall surface by urging the circuit board with the urging means, and the secondary battery is accommodated and held in the battery holding portion. The secondary battery is urged by the urging means, and the shoulders of the secondary battery are placed in contact with the battery positioning wall surface, and are placed in the mold, and the resin is filled in the resin filling space. The intermediate finished product is obtained by performing resin molding after filling.
[0019]
  the above3A invention, 3B inventionAccording to this manufacturing method, when the circuit board is urged to abut against the substrate positioning wall formed in the mold, and the secondary battery sealing plate side is urged to abut against the battery positioning wall, The gap between the secondary battery and the circuit board is positioned at a fixed size, and the secondary battery and the circuit board are integrated by filling and molding resin in the gap. The intermediate finished product formed in this way varies in height due to variations in the height of the secondary battery. This variation in height dimension is absorbed by a change in thickness on the bottom surface side of the secondary battery when resin molding is performed so that the outer dimension is constant during secondary molding in which exterior coating is performed. In addition, when the bottom surface of the secondary battery is urged against the board positioning wall surface, the circuit board is urged to abut against the board positioning wall surface so that the secondary battery and the circuit board are placed between them. When the gap is filled with resin and integrated, the variation in the height dimension of the secondary battery and the variation in the position of the circuit board in a position unregulated state are absorbed by the change in the height dimension of the filled resin, The height of the intermediate finished product is finished constant.
[0020]
  In addition, this application4A inventionThe battery pack manufacturing method according toConnect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering In the method, as the mold, a battery holding portion for accommodating and holding a secondary battery, a pair of left and right substrate positioning grooves for fitting and holding both ends of the circuit board to position the circuit board, and a secondary battery Abuts both shoulders on the sealing plate side A pair of left and right battery positioning walls for positioning the secondary battery, and a pair of right and left pair of substrate positioning grooves and a pair of left and right battery positioning walls in a direction perpendicular to the positioned circuit board. The battery positioning wall surface comprising: a substrate holding portion having a side wall; and biasing means for biasing the substrate holding portion to bring the battery positioning wall surfaces into contact with the shoulder portions of the secondary battery. Is a space filled with the circuit board positioned in the substrate positioning groove, the sealing plate of the secondary battery, and the side wall when the abutment against both the shoulders of the secondary battery, The resin-filled object is positioned in the circuit board positioning groove, the secondary battery is accommodated and held in the battery holding part, and the board holding part is Energizing by the energizing means, the battery The intermediate finished product is obtained by placing the positioning wall in contact with the shoulders of the secondary battery in the mold, filling the resin filling space with resin, and performing resin molding.It is characterized by this.
  In the battery pack manufacturing method according to the present invention 4B, a circuit board having an external connection terminal formed on one side thereof is connected to a sealing plate of a secondary battery formed in a flat rectangular shape by a connecting member, and the circuit board is directed to the other direction. The resin-filled object is formed with a gap so as to face the sealing plate, and the resin-filled object is placed in a mold with the secondary battery and the circuit board positioned at predetermined positions. The resin filling space between the secondary battery and the circuit board is molded with resin to form an intermediate finished product that integrates the secondary battery and the circuit board, and at least the external connection terminals of the intermediate finished product are provided. A method of manufacturing a battery pack that is externally exposed to form an exterior covering, wherein the mold includes a battery holding portion that accommodates and holds a secondary battery, and both ends of the circuit board are fitted and held to position the circuit board. A pair of left and right board positions to perform Determination groove, a pair of left and right battery positioning walls for positioning the secondary battery by contacting both shoulders on the sealing plate side of the secondary battery, and a pair of left and right substrate positioning grooves and a pair of left and right batteries A substrate holding part having a side wall in a direction perpendicular to the positioned circuit board connecting each of the positioning wall surfaces; and urging the substrate holding part to connect the battery positioning wall surface to the both sides of the secondary battery. A circuit board positioned in the substrate positioning groove when the battery positioning wall faces the shoulders of the secondary battery, and a secondary battery. Using a mold configured so that a space surrounded by the sealing plate and the side wall is a resin-filled space, and positioning the resin-filled object in the circuit board positioning groove, A secondary battery is accommodated and held in the battery holding part, The substrate holding part is urged by an urging means, and the battery positioning wall surface is placed in contact with the shoulders of the secondary battery, and is placed in the mold, and the resin filling space is filled with resin. The intermediate finished product is obtained by performing resin molding after filling.
[0021]
  the above4A invention, 4B inventionAccording to this manufacturing method, the formation direction of the battery positioning wall surface and the substrate positioning groove is formed in parallel in the mold, and the edge of the circuit board is fitted into the substrate positioning groove in the mold. When the secondary battery is urged so that its bottom side comes into contact with the battery positioning wall surface, the secondary battery and the circuit board are integrated by filling the gap between them with resin, The position of the circuit board is regulated, and the variation in the height dimension of the secondary battery is absorbed by the change in the height dimension of the filled resin, and the height of the intermediate finished product is finished constant. When an exterior covering is formed by exposing a predetermined portion including the external connection terminal of the intermediate finished product to the outside, the position of the external connection terminal is accurately positioned and can be formed into a robust battery pack that is difficult to disassemble. Also, if the circuit board is urged to abut against the substrate positioning wall surface and the secondary battery sealing plate side is urged against the battery positioning wall surface, the gap between the secondary battery and the circuit board is The secondary battery and the circuit board are integrated by positioning with a certain dimension and filling and molding the resin in the gap. The intermediate finished product formed in this way varies in height due to variations in the height of the secondary battery. This variation in height dimension is absorbed by a change in thickness on the bottom surface side of the secondary battery when resin molding is performed so that the outer dimension is constant during secondary molding in which exterior coating is performed.
[0022]
  In addition, the battery pack manufacturing method according to the fifth invention of the present application,Flat rectangleSeal of secondary battery formed onOn the boardCircuit board with external connection terminals on one sideBetweenThe resin substrate is formed by connecting the circuit board to the secondary battery by a connecting member that is arranged with a gap therebetween and elastically urges the circuit board in a direction away from the secondary battery, and from the bottom surface of the secondary battery. The resin-filled object is disposed against a biasing force of the connection member in a mold in which an internal space in which the dimensions to the formation surface of the external connection terminal of the circuit board are regulated is formed, and a secondary battery and a circuit are arranged. Resin molding is performed to fill the gap between the substrate and the resin, and the secondary battery and the circuit board are formed into an intermediate finished product, and at least the external connection terminals of the intermediate finished product are exposed to the outside to cover the exterior. It is characterized by forming.
[0023]
  According to the manufacturing method of the fifth aspect of the invention, the resin-filled object in a state where the circuit board is urged away from the secondary battery by the connecting member is connected to the external connection terminal of the circuit board from the bottom surface of the secondary battery. Since it is placed in a mold in which an internal space with a regulated dimension up to the forming surface is formed, the connecting member presses the secondary battery and circuit board against the opposing wall surface of the internal space due to its elasticity. The circuit board can be fixed at a fixed position at the same time as absorbing the variation in dimensions, and the dimensions from the bottom surface of the secondary battery to the circuit board can be made constant. If resin is filled in the space between the secondary battery and the circuit board in this state, the dimensions from the bottom surface of the secondary battery to the formation surface of the external connection terminal of the circuit board are integrated by integrating the secondary battery and the circuit board. Can be formed into an intermediate finished product having a predetermined value. A battery pack can be completed by forming an exterior coating on the intermediate finished product.
[0024]
  In each of the above manufacturing methods, by forming an undercut part in the circuit board direction on the sealing plate of the secondary battery, the resin filled in the gap between the circuit board enters the undercut part and is strong with the secondary battery. Are formed into a robust structure that is difficult to disassemble.
[0025]
  Further, the outer covering is formed on the intermediate finished product by forming at least the external connection terminal from the external connection terminal formation surface of the circuit board to the sealing plate of the secondary battery, and forming an upper molding portion. Secondary molding a lower molding part formed at a predetermined height on the bottom surface of the secondary battery and a connection molding part connecting the upper molding part and the lower molding part with the short side surface of the secondary battery, the secondary battery side The sheet thickness was added to the secondary battery by covering the peripheral surface, part of the side periphery of the upper molding part and the lower molding part, and the joint molding part, and winding the sheet. It can be formed into a thin battery pack. When the connection molding part is formed so as to enter a rectangular line surrounding the arc part of both ends of the secondary battery having a cross-sectional shape formed into an oval shape, the width dimension of the battery pack is changed to the width dimension of the secondary battery. The thickness of the sheet can be added to prevent an unnecessary increase in dimensions, and if the connecting molded part is formed only on one side of the rectangular line surrounding the arc, the cross-sectional shape of the battery pack becomes asymmetrical, and the direction of loading into the device is changed. In addition to the restriction, the arc portion can correspond to the round shape formed at the corner of the device case.
[0026]
  The outer covering is formed on the external connection terminal forming surface side of the circuit board and / or the bottom surface side of the secondary battery by covering the intermediate finished product with a cylindrical body or a bottomed cylindrical body formed at a predetermined height. When the predetermined portion including the external connection terminal is exposed to the open end and the resin is filled and molded, the entire peripheral surface of the intermediate finished product is filled with the resin at the open end to form the predetermined portion including the external connection terminal. It can be easily exposed by external exposure.
[0027]
  In addition, the exterior covering can be molded so that the entire outer peripheral surface of the intermediate finished product is covered with resin by exposing a predetermined portion including the external connection terminal to the outside, and the intermediate finished product can be covered in a sealed state. A battery pack having excellent moisture resistance can be formed.
[0028]
  In addition, an insulating coating is applied to the portion of the mold used for primary molding and secondary molding that comes in contact with the active portion exposed from the resin filling target or intermediate finished product during resin filling molding or the exterior. It is possible to prevent the occurrence of short circuit or leakage during coating.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
[0030]
  The present embodiment shows an example in which a battery pack to be applied to a mobile phone is configured using a flat rectangular lithium ion secondary battery. Battery packs applied to mobile phones are compact, lightweight, thin, high energy density for high functionality, mechanical strength that can withstand impacts such as drops that are unavoidable as portable devices, structures that are difficult to disassemble, and short circuits It is required to have a safety function for protecting the secondary battery from overcharge, high temperature, etc., and the battery pack shown below is configured to satisfy these requirements.
[0031]
  FIG. 1 shows an external appearance of a battery pack 1 according to an embodiment. An external connection terminal 6 composed of a positive electrode terminal, a negative electrode terminal, and a temperature detection terminal is externally exposed on one end face, and a submerged seal is placed on a test terminal 30 described later. 9 is stuck and it is comprised by the flat asymmetrical shape. FIG. 2 is an exploded view of the battery pack 1 and shows each component. Details of each component and a method for manufacturing the battery pack 1 using each component will be described below.
[0032]
  As shown in FIG. 3, a lithium ion secondary battery (hereinafter referred to as a secondary battery) 2 has a power generation element housed in an aluminum battery can 22 formed in a bottomed cylindrical shape having an oblong cross section. The opening end is sealed by laser welding the sealing plate 23. The sealing plate 23 which is joined to the battery can 22 and becomes the battery positive electrode has a battery negative electrode 25 formed in a convex manner at the center thereof by insulation with the upper gasket 24a and the lower gasket 24b. Further, mushroom-like engaging projections (undercut portions) 26 and 26 are formed on both sides of the sealing plate 23 by pressing the sealing plate 23. Reference numeral 27 denotes a sealing plug for closing the electrolytic solution injection port. After the electrolytic solution is injected into the battery can 22, the electrolytic solution injection port is closed by the sealing plug 27, and the sealing plug 27 is welded to the sealing plate 23.
[0033]
  The engaging protrusion 26 is formed in a mushroom shape as shown in the figure when a cylindrical protruding portion is formed at a predetermined position of the sealing plate 23 by pressing and is pressed so that its head opens to the periphery. . Note that the engagement protrusions 26 can be formed by welding a mushroom-like member or an inverted L-shaped member on the sealing plate, not by pressing.
[0034]
  In the secondary battery 2, as shown in FIG. 3C, one connection piece 10 a of the temperature fuse 10 is welded to the battery negative electrode 25. A heat insulating sheet 16 is adhered to the upper surface of the thermal fuse 10 as shown by a broken line, and the thermal fuse 10 is prevented from being blown during resin filling described later. The other connection piece 10b of the thermal fuse 10 is disposed on an insulating paper 21 adhered on the sealing plate 23, and is joined to one end of a negative electrode lead plate 5 described later by spot welding. Further, a thermal conductive adhesive is applied between the thermal fuse 10 and the secondary battery 2, and the thermal fuse 10 is thermally coupled to the secondary battery 2.
[0035]
  As shown in FIG. 4A, the circuit board 3 constituting a protection circuit that protects the secondary battery 2 from overcharge, overdischarge, and overcurrent has an external connection terminal 6 as shown in FIG. As shown in FIG. 4B, an electronic component 31 such as an integrated circuit component is mounted on the other surface on the side of the secondary battery 2 and the secondary battery 2 is mounted on both sides. A positive electrode soldering land 32 and a negative electrode soldering land 33 for connection are formed. In each figure, the display of circuit patterns and through holes formed on the circuit board 3 is omitted.
[0036]
  As shown in FIG. 4C, one end of a positive electrode lead plate (connecting member) 4 is soldered between the positive electrode soldering land 32 and an electronic component 31 with an insulating paper 34 interposed therebetween. One end of the negative electrode lead plate (connection member) 5 is soldered to 33.
[0037]
  As shown in FIG. 5A, the circuit board 3 after the connection processing has the other end of the positive electrode lead plate 32 on the plate surface of the sealing plate 23 and the other of the negative electrode lead plate 33 with respect to the secondary battery 2. The ends are spot welded onto the other connection piece 10b of the thermal fuse 10, respectively. In this connection state, since the circuit board 3 is in a direction orthogonal to the plate surface of the sealing plate 23, as shown in FIG. 5 (b), the positive and negative lead plates 4, 5 are bent, A gap is provided between the plate surface of the circuit board 3 and the plate surface of the sealing plate 23, and is shaped into a substantially parallel state. Thus, the circuit board 3 is connected to the secondary battery 2, and the resin filling object 7 as shown to Fig.11 (a) is formed.
[0038]
  A resin is filled in the gap between the secondary battery 2 and the circuit board 3 of the resin-filled object 7 so that the secondary battery 2 and the circuit board 3 are integrated. At this time, it is important to mold the resin so that the height H from the bottom surface of the secondary battery 2 to the formation surface of the external connection terminal 6 of the circuit board 3 becomes a predetermined dimension. The manufacturing method will be described below.
(First manufacturing method)
  As shown in FIG. 6A, the lower mold 36 of the primary mold 35 is configured such that the movable part 41 can be moved to the fixed part 42 side by the biasing means 45, and the movable part 41 has a vacuum suction part 43. Is provided. When the movable part 41 is moved backward, the resin filling object 7 (only the secondary battery 2 and the circuit board 3 are shown in FIG. 6) is arranged in the lower mold 36, and the movable part 41 is moved forward to move the secondary part. The battery 2 is positioned by pressing the bottom surface of the battery 2 against the inner wall surface of the fixing portion 42. On the other hand, the circuit board 3 is positioned in close contact with the wall surface of the vacuum suction portion 43 by vacuum suction from the vacuum suction portion 43.
[0039]
  The height dimension H from the bottom surface of the secondary battery 2 to the surface where the external connection terminals 6 of the circuit board 3 are formed varies in the height dimension h of the secondary battery 2 and the circuit board 3 is not fixed at a fixed position. The circuit board 3 is fixed at a fixed position by vacuum suction, and the moving amount of the movable part 41 changes according to the height dimension h of the secondary battery 2. The secondary battery 2 and the circuit board 3 that are positioned in the height of the gap between the secondary battery 2 and the circuit board 3 are changed from the bottom surface of the secondary battery 2 to the formation surface of the external connection terminal 6 of the circuit board 3 by the change in the height dimension G between them. The dimension H is in a constant state.
[0040]
  The positioning of the secondary battery 2 and the circuit board 3 when the resin-filled object 7 is resin-filled and molded may be configured such that the lower mold 36a of the primary mold 35 is as shown in FIG. 6B. it can. The circuit board 3 is brought into close contact with the substrate positioning wall surface 75 by vacuum suction, and the shoulders of the secondary battery 2 are brought into contact with the battery positioning wall surface 77 when the pressing shaft 85 is urged by the urging means 76. In this configuration, the distance G between the secondary battery 2 and the circuit board 3 is fixed, and the variation in the height dimension h of the secondary battery 2 varies from the bottom surface of the secondary battery 2 to the external connection terminal 6 of the circuit board 3. Although it becomes the fluctuation | variation of the height dimension H4 to a formation surface, this fluctuation | variation of the height dimension H4 is absorbed by the secondary mold mentioned later.
[0041]
  The upper mold 37 shown in FIG. 7 is lowered on the lower molds 36 and 36a in which the secondary battery 2 and the circuit board 3 are positioned as described above, and the secondary battery 2 is connected to the secondary battery 2 from the gate 44 provided on the upper mold 37. Resin is injected into the gap between the circuit board 3. As shown in FIG. 8, the injected resin also wraps around the electronic component 31 mounted on the circuit board 3 and the lead plates 4 and 5 of the positive electrode and the negative electrode and is joined to the circuit board 3, and is secondary. The primary mold body 11 is formed by going around the undercut portion of the engaging protrusion 26 formed on the sealing plate 23 of the battery 2 and joining the sealing plate 23. A hot melt is preferable in which the resin is fluidized at a temperature that does not adversely affect the electronic component 31, the secondary battery 3, or the thermal fuse 10, and is cured when the temperature is lowered.
[0042]
  Even if the temperature of the resin is relatively low, the temperature exceeds 200 ° C. Therefore, when the temperature fuse 10 whose fusing temperature is set to 104 ° C. is touched, the temperature fuse 10 is blown to stop the function of the battery pack 1 itself. I will let you. As countermeasures, a method of thermally shielding between the thermal fuse 10 and the resin by a heat insulating sheet, a method of arranging the thermal fuse 10 at a position where it is not in direct contact with the resin, etc. are proposed separately by the invention. Then, as described above, the heat insulating sheet 16 is stuck on the thermal fuse 10 to suppress the heat of the resin from being transferred to the thermal fuse 10. Further, a portion of the primary mold 35 corresponding to the position where the thermal fuse 10 is disposed is formed of a material having good thermal conductivity (for example, aluminum), and the heat of the resin is dissipated to the mold side to the thermal fuse 10. It can also be solved by suppressing the heat conduction.
[0043]
  Since the live parts connected to the positive electrode and the negative electrode of the secondary battery 2 are exposed to the outside, the resin-filled object 7 does not cause a short circuit or leakage when accommodated in the primary mold 35. An insulating coating by alumina treatment or fluororesin treatment is applied to a portion where the exposed live part of the primary mold 35 may come into contact. Further, the insulating coating is formed by forming the mold with aluminum and anodizing the required portion, and at the same time, the thermal effect of the filling resin on the thermal fuse 10 is suppressed by improving the thermal conductivity.
[0044]
  After the filled resin is cured, the upper die 37 is raised, the vacuum suction is released, and the movable portion 41 or the urging means 76 is retracted. As shown in FIG. Are integrated by the primary mold body 11 formed by curing the resin, and can be taken out from the lower mold 36 as an intermediate finished product 8 as shown in FIG. The battery pack 1 can be formed by applying an outer covering around the intermediate finished product 8.
[0045]
  Here, the exterior covering is applied by secondary molding and attachment of a winding sheet. Before performing the secondary molding, the insulator 14 is attached to the bottom surface of the secondary battery 2.
[0046]
  In the secondary molding, as shown in FIG. 9, the intermediate finished product 8 is placed in the secondary mold 46 and a resin is molded at a required portion of the intermediate finished product 8. The lower mold 47 of the secondary mold 46 is formed with a recess 50 for accommodating the intermediate finished product 8, and one side wall surface of the recess 50 is used for three external connection terminals that are urged inwardly. A protrusion 51 and a test terminal protrusion 52 are provided, and a bottom surface protrusion 54 that is urged inward is provided on the opposite side wall surface. When the intermediate finished product 8 is disposed in the recess 50 and the external connection terminal protrusion 51, the test terminal protrusion 52, and the bottom surface protrusion 54 are advanced, the external connection terminal protrusion 51 is formed on the circuit board 3. The test terminal protrusions 52 are in pressure contact with the three external connection terminals 6, and the bottom surface protrusions 54 are in pressure contact with the insulator 14 attached to the bottom surface of the secondary battery 2.
[0047]
  The lower die 47 containing the intermediate finished product 8 is closed with the upper die 48, and the secondary mold die 46 is filled with resin from the gate 53 provided on the upper die 48. The resin is injected into the secondary mold 46 from four places, and as shown in FIG. 10, the external connection terminals 6 and the test terminals 30 of the intermediate finished product 8 are exposed to the outside, and the circuit board 3 and the primary mold body 11 are exposed. 11 (c), the upper molded portion 17 is formed on the sealing plate 23 of the secondary battery 2, and the periphery of the insulator 14 is wrapped around the bottom surface of the secondary battery 2 to a predetermined thickness. A lower molding portion 18 fixed to the upper portion is formed, and a connection molding portion 19 is formed to connect the upper molding portion 17 and the lower molding portion 18 at the side corners of the secondary battery. As shown in FIG. 12, the connection molding portion 19 is formed of resin so that the 90 ° portion on one side of the arc side surface of the secondary battery 2 having an oval cross-sectional shape is formed at a right angle. The secondary molding body 12 shown in FIG. 2 is formed by the upper molding part 17, the lower molding part 18, and the connection molding part 19.
[0048]
  Incidentally, in the case of the intermediate finished product 8 that is resin-filled and molded using the lower die 36a shown in FIG. 6B, the intermediate finished product 8 has a variation of the height h of the secondary battery 2 as described above. Although the height dimension H4 varies, the variation of the height dimension H4 is absorbed by molding the secondary mold body 12 to a constant height dimension.
[0049]
  Further, in the intermediate finished product 8, the live parts connected to the positive electrode and the negative electrode of the secondary battery 2 such as the external connection terminal 6 are exposed to the outside, so that the secondary mold die is the same as the primary mold die 35. Also in 46, the exposed live parts of the secondary mold 46 are in contact with the exposed parts, that is, the external connection terminals 6, the test terminals 30, etc., so that the intermediate finished product 8 does not cause a short circuit or leakage. The external connection terminal projection 51 and the test terminal projection 52 are provided with an insulating coating by alumina treatment or fluororesin treatment.
[0050]
  A stepped portion 38 is formed near the secondary battery on the peripheral surface of the upper molding portion 17, and the winding sheet 20 is wound around the side peripheral surface of the secondary battery 2 using this as a bonding positioning line. Worn. Thereafter, the operation state is inspected using the test terminal 30, and the submerged seal 9 is stuck in the recess around the test terminal 30 for the inspection-accepted product to form the battery pack 1 as shown in FIG. 1. .
[0051]
  As shown in FIG. 1, the battery pack 1 formed in this way has both shoulder portions on one flat surface formed at arc corners where arcs on both sides of the secondary battery 2 appear on the surface, and both on the other surface. Since the shoulder portion is formed at the square corner by the connection molding portion 19, the external connection terminal 6 can be prevented from being reversely loaded into the device in combination with the asymmetrical position. The arc corner corresponds to the rounded shape of the corner of the device case, and can be accommodated in the device without forming a useless space.
[0052]
  In addition, since the bottom projection 54 of the lower mold 47 contacts the central portion of the insulator 14 attached to the bottom surface of the secondary battery 2 and the resin is not molded, A recess 39 is formed as shown in FIG. As described above, since the battery pack 1 is loaded in the battery pack housing space where the device is narrow, it is difficult to remove the battery pack unless there is a clue when the battery pack is removed from the housing space, but the recess 39 is formed. Thus, the toe can be hung on the bottom surface of the battery pack 1, and the recess 39 becomes a so-called nail hook to facilitate the removal of the battery pack 1.
(Second manufacturing method)
  The second manufacturing method is different from the method of forming the primary mold body 11 by filling the above-described resin filling object 7 with resin. Hereinafter, the second manufacturing method will be described by omitting the description of the same manufacturing method by assigning the same reference numerals to the components common to the first manufacturing method.
[0053]
  The resin-filled object 7 formed as shown in FIG. 11A is disposed in the lower mold 56 of the primary mold shown in FIG. The circuit board 3 is positioned with both ends abutting against the substrate positioning wall surface 60 when the pressing shaft 57 provided on one wall surface of the lower die 56 is pushed out by the urging means 59. Further, the secondary battery is positioned by pressing the pressing shaft 58 provided on the other wall surface of the lower die 56 by the urging means 62 so that both end portions of the sealing plate 23 abut against the battery positioning wall surface 61. By this positioning, the state where the circuit board 3 is not in a fixed position is restricted to a height dimension H2 from the bottom surface of the secondary battery 2 to the surface where the external connection terminals 6 are formed on the circuit board 3. Thus, the upper mold (not shown) is lowered on the lower mold 56 where the secondary battery 2 and the circuit board 3 are positioned, and is formed between the secondary battery 2 and the circuit board 3 at regular intervals. The gap G2 is filled with resin, and the resin filled with the secondary battery 2 and the circuit board 3 is formed into an integrated intermediate product 8 by the cured primary mold body 11.
[0054]
  In the intermediate finished product 8 formed by the primary molding, the overall height dimension H2 varies depending on the variation in the height dimension h of the secondary battery 2. The fluctuation of the height dimension H2 is absorbed by the change in the thickness of the lower molding portion 18 molded on the bottom surface of the secondary battery 2 during the secondary molding by the secondary mold 46 shown in FIG. The battery pack 1 having a certain height is formed. Since the method of forming the exterior coating is the same as that according to the first manufacturing method, description thereof is omitted.
[0055]
  In the positioning of the secondary battery 2 using the lower die 56, the variation in the height dimension H2 of the intermediate finished product 8 due to the variation in the height dimension h of the secondary battery 2 is configured as shown in FIG. It is possible to form the intermediate finished product 8 having a certain height H5 by using the lower die 56a.
[0056]
  In FIG. 14B, the secondary battery 2 is positioned by contacting the battery positioning wall surface 83 of the lower die 56 a by being urged by the battery urging means 81, and the circuit board 3 is laid by the substrate urging means 80. By being urged, the substrate is positioned in contact with the substrate positioning wall surface 82 formed in the lower die 56a. With the configuration of the lower mold 56a, the circuit board 3 is positioned at a fixed position, and the variation in the height h of the secondary battery 2 is absorbed by the change in the gap G5 between the secondary battery 2 and the circuit board 3, Completed as an intermediate finished product 8 having a constant height H5.
(Third production method)
  In the third manufacturing method, the resin filling method for the resin filling object 7 described above is different. Hereinafter, the same reference numerals are given to components common to the first and second manufacturing methods. The description of the same manufacturing method is omitted, and the third manufacturing method will be described.
[0057]
  In the third manufacturing method, as shown in FIG. 15, the positive electrode lead plate 4 a and the negative electrode lead plate 5 a that connect the circuit board 3 to the secondary battery 2 are formed of a material having elasticity against bending. After soldering one end side of the positive electrode lead plate 4a and the negative electrode lead plate 5a to the circuit board 3, the other end is spot welded to the secondary battery 2 as shown in FIG. ), When the circuit board 3 is bent so as to be substantially parallel to the sealing plate 23 of the secondary battery 3, the positive electrode lead plate 4a and the negative electrode lead plate 5a have elasticity against the bending. Therefore, not in parallel with the sealing plate 23, but as shown in FIG. 15, the circuit board 3 is formed with the resin-filled object 7 in an inclined angle and connected to the secondary battery 2.
[0058]
  As shown in FIG. 16, the resin-filled object 7 is a lower mold 64 of a primary mold in which a dimension H <b> 3 between the external connection terminal 6 formation surface of the circuit board 3 and the bottom surface of the secondary battery 2 is regulated. Place in. At this time, since the circuit board 3 is not parallel to the sealing plate 23 of the secondary battery 2, the circuit board 3 is press-fitted into the lower mold 64. However, when the circuit board 3 is press-fitted, the lower mold 64 in which the height dimension H 3 is regulated. At the same time, the secondary battery 2 is pressed against the opposing wall surface by the elasticity of the positive electrode lead plate 4 and the negative electrode lead plate 5. By accommodating the resin-filled object 7 in the lower mold 64 in this way, the positive lead plate 4 and the negative lead plate 5 are in a state in which the secondary battery 2 has a variation in the height dimension h and the circuit board 3 is not in a fixed position. Thus, a state in which the dimension H3 between the formation surface of the external connection terminal 6 of the circuit board 3 and the bottom surface of the secondary battery 2 is regulated is obtained.
[0059]
  When the upper mold (not shown) is lowered onto the lower mold 64 containing the resin filling object 7 as described above and the gap G between the secondary battery 2 and the circuit board 3 is filled with the resin, the secondary mold is obtained. The battery 2 and the circuit board 3 are integrally fixed by filled resin, and formed into an intermediate finished product 8 as shown in FIG.
[0060]
  Since the formation of the exterior coating on the intermediate finished product 8 can be performed in the same manner as the first and second manufacturing methods, the description thereof is omitted.
(Fourth manufacturing method)
  The fourth manufacturing method is different from the above-described method of forming the primary mold body 11 by filling the resin filling object 7 with resin. Hereinafter, the same reference numerals are given to the components common to the first and second manufacturing methods, and the description of the same manufacturing method is omitted, and the third manufacturing method will be described.
[0061]
  The resin-filled object 7 formed as shown in FIG. 11 (a) is a primary material shown in FIG. 17 (a).
It is arranged in the lower mold 91 of the mold. The circuit board 3 is positioned by fitting both ends into a board positioning groove 92 formed in the lower die 91. Further, the secondary battery is pushed out by the urging means 94 provided in the lower die 91, so that both end portions of the sealing plate 23 come into contact with the battery positioning wall surface 93 to be positioned. The state in which the circuit board 3 is not in a fixed position by this positioning is regulated by the height dimension H6 from the bottom surface of the secondary battery 2 to the surface of the circuit board 3 where the external connection terminals 6 are formed. Thus, the upper mold (not shown) is lowered on the lower mold 56 where the secondary battery 2 and the circuit board 3 are positioned, and is formed between the secondary battery 2 and the circuit board 3 at regular intervals. The gap G6 is filled with resin, and the resin filled with the secondary battery 2 and the circuit board 3 is formed into an intermediate finished product 8 integrated by the cured primary mold body 11.
[0062]
  In the intermediate finished product 8 formed by the primary molding, the overall height dimension H2 varies depending on the variation in the height dimension h of the secondary battery 2. The fluctuation of the height dimension H2 is absorbed by the change in the thickness of the lower molding portion 18 molded on the bottom surface of the secondary battery 2 during the secondary molding by the secondary mold 46 shown in FIG. The battery pack 1 having a certain height is formed. Since the method of forming the exterior coating is the same as that according to the first manufacturing method, description thereof is omitted.
[0063]
  In positioning of the secondary battery 2 using the lower mold 91, the variation in the height dimension H6 of the intermediate finished product 8 due to the variation in the height dimension h of the secondary battery 2 is configured as shown in FIG. By using the lower mold 91a, it is possible to form the intermediate finished product 8 having a certain height dimension H7.
[0064]
  In FIG. 17B, the secondary battery 2 is urged by the battery urging means 97 to be brought into contact with the battery positioning wall surface 96 of the lower die 91a, and the circuit board 3 is placed in the board positioning groove 95. Both ends are inserted and positioned. With the configuration of the lower die 91a, the circuit board 3 is positioned at a fixed position, and the variation in the height dimension h of the secondary battery 2 is absorbed by the change in the gap G7 between the secondary battery 2 and the circuit board 3, Completed as an intermediate finished product 8 having a constant height dimension H7.
[0065]
  About the battery pack 1 manufactured by each of the above first to fourth manufacturing methods, a free drop test in which 6 cycles of each surface are dropped on concrete at a drop height of 1.5 m, on a steel plate at a drop height of 1.0 m. Random drop test to see mechanical performance after dropping 50 times, drop 200 times to see electrical characteristics, heat shock test to apply temperature change from -40 ° C to 80 ° C multiple times, vibration in 3 directions A vibration test for applying a load and a terminal strength test for applying a load to the external connection terminals were performed. The battery pack 1 after this test was attached to the device, and it was verified whether there was any abnormality in the attachment, whether it operated normally, and whether there was any deformation or looseness. As a result, no failure was observed after each test, which proved to be a robust structure.
[0066]
  Further, although the influence on the secondary battery 2 by filling and molding a resin having a temperature exceeding 200 ° C. or the damage of the thermal fuse 10 disposed in the resin filling portion was verified, no abnormality occurred.
[0067]
  In addition, in order to verify the state when the completed battery pack 1 is disassembled, when deliberate disassembly is attempted, it is clear that disassembly is extremely difficult as compared with a structure using a general pack case. Yes, if the primary mold body 11 is destroyed, the engaging projections 26 provided at both ends of the sealing plate 23 are destroyed, and the positive and negative lead plates 4 and 5 and the connecting portions existing in the filling molding are destroyed. It was in a state where it could be easily determined that it was decomposed.
[0068]
  In addition, the accuracy of the finished external dimensions is within the error range of ± 0.1 to 0.2 mm for each part, and the dimensions from the bottom surface to the external connection terminal 6 where accuracy is particularly required are also within the error. It has been confirmed that there will be no problem in connection with the.
[0069]
  In the configuration described above, the exterior covering for the intermediate finished product 8 is formed by the secondary molded body 12 and the winding sheet 13 which are resin-molded at a required portion, but is not limited to this. The intermediate finished product 8 is inserted into a cylindrical outer case 71 as shown in FIG. 5A, the lower opening is sealed by resin filling, and the external connection terminal 6 and the test terminal 30 are exposed to the upper opening. When the resin is filled in this way, the outer shape can be configured in the same manner as the battery pack 1.
[0070]
  Further, as shown in FIG. 18B, the intermediate finished product 8 is inserted into a bottomed cylindrical outer case 72 in which openings are formed at positions corresponding to the external connection terminals 6 and the test terminals 30, and the lower opening is opened. The outer shape similar to that of the battery pack 1 can also be formed by filling the portion with resin and sealing. The outer case 72 is a bottomed cylindrical body that is open downward, but is formed in a bottomed cylindrical shape that is open upward, and is filled with resin so that the external connection terminals 6 and the test terminals 30 are exposed to the upper opening. Even so, the outer shape can be configured in the same manner as the battery pack 1.
[0071]
  Also, the battery pack 1 as shown in FIG. 1 can be formed by resin molding so that the external connection terminals 6 and the test terminals 30 are exposed to the outer peripheral surface of the intermediate finished product 8.
[0072]
【The invention's effect】
  As described above, according to the present invention, it is possible to configure a battery pack in which the dimensions from the bottom surface to the external connection terminal on the opposite surface are constant and the secondary battery and the circuit board are integrated by resin molding. In addition, as a battery power source suitable for a small portable electronic device, it is possible to provide a battery pack having connection reliability and robustness capable of withstanding an impact such as dropping.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an appearance of a battery pack according to an embodiment.
FIG. 2 is an exploded perspective view showing each component of the battery pack.
3A is a plan view showing the configuration of the secondary battery, FIG. 3B is a cross-sectional view of the sealing plate side, and FIG. 3C is a plan view with a thermal fuse attached.
FIGS. 4A and 4B are perspective views showing the configuration of the circuit board, in which FIG. 4A is an outer surface side, FIG. 4B is an inner surface side, and FIG.
FIG. 5 is a perspective view showing a state where the circuit board is attached to the secondary battery.
FIG. 6 is a schematic diagram illustrating resin filling by the first manufacturing method.
FIG. 7 is a perspective view showing the configuration of the primary mold as described above.
FIG. 8 is a cross-sectional view showing a state where a primary mold body is formed.
FIG. 9 is a perspective view showing a configuration of a secondary mold.
FIG. 10 is a cross-sectional view showing a state where a secondary mold body is formed.
FIGS. 11A and 11B are perspective views sequentially showing formation states at each stage of the manufacturing process. FIGS.
FIG. 12 is a cross-sectional view illustrating a formation position of a connection molding portion.
FIG. 13 is a perspective view showing a recess formed on the bottom surface of the intermediate finished product.
FIG. 14 is a schematic diagram illustrating resin filling by a second manufacturing method.
FIG. 15 is a perspective view showing a connection state of a circuit board to a secondary battery according to a third manufacturing method.
FIG. 16 is a schematic diagram illustrating resin filling by a third manufacturing method.
FIG. 17 is a schematic diagram for explaining resin filling by a fourth manufacturing method.
FIG. 18 is a perspective view showing a configuration of an exterior case showing another aspect of the exterior covering.
FIG. 19 is a schematic diagram illustrating the accuracy of the formation position of the external connection terminal of the battery pack.
[Explanation of symbols]
  1 Battery pack
  2 Secondary battery
  3 Circuit board
  4 Positive lead plate (connection member)
  5 Negative lead plate (connection member)
  6 External connection terminals
  7 Resin filling object
  8 Intermediate finished product
  10 Thermal fuse
  11 Primary mold body
  12 Secondary mold body
  13 Wrap sheet
  16 Insulation sheet
  17 Upper molding part
  18 Lower molding part
  19 Connection molding part
  23 Sealing plate
  26 Engagement protrusion (undercut part)
  35 Primary mold
  36, 47, 56, 64 Lower mold
  41 Moving parts
  42 fixed part
  43 Vacuum suction part
  45, 59, 62 Biasing means
  46 Secondary mold
  51 External connection terminal protrusion
  57, 58 Press shaft
  60, 75, 82 Wall surface for substrate positioning
  61, 77, 83 Battery positioning wall
  92, 95 Substrate positioning groove

Claims

With connecting a circuit board to form the external connection terminal on one surface to the sealing plate of a secondary battery formed in flat rectangular by connecting members, at intervals gap to the circuit board and other surface faces the sealing plate arranged to form a resin-filled objects, this resin filling object by positioning the secondary battery and the circuit board at a predetermined position is placed in a mold, the resin in the gap between the secondary battery and a circuit board Forming an intermediate finished product in which the secondary battery and the circuit board are integrated to form an exterior coating by exposing at least external connection terminals of the intermediate finished product to the outside. A battery pack manufacturing method.

Connect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering A method,
As the mold,
A battery holding unit for accommodating and holding the secondary battery;
Board positioning wall for positioning and holding the circuit board by vacuum suction, a pair of left and right battery positioning walls that contact the shoulders on the sealing plate side of the secondary battery to position the secondary battery, and a board positioning wall And a pair of left and right battery positioning wall surfaces, and a side wall in a direction perpendicular to the positioned circuit board surface, and is movable in the direction of contact with the sealing plate of the secondary battery. When,
Urging means for urging the substrate holding part to bring the battery positioning wall surface into contact with the shoulders of the secondary battery;
A space surrounded by the circuit board positioned on the substrate positioning wall, the sealing plate of the secondary battery, and the side wall when the battery positioning wall contacts the shoulders of the secondary battery. Using a mold configured to be a resin-filled space,
The resin-filled object is positioned by vacuum-sucking the circuit board to the board positioning wall surface.
The secondary battery is accommodated and held in the battery holding portion, the substrate holding portion is urged by the urging means, and the battery positioning wall surfaces are brought into contact with the shoulder portions of the secondary battery. A method of manufacturing a battery pack, wherein the intermediate finished product is obtained by being placed in the mold in a state, filling the resin filling space with resin, and performing resin molding .

Connect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering A method,
As the mold,
A battery holder for holding and holding the secondary battery so as to be movable in the direction of separation from the circuit board; and
Board positioning wall for positioning and holding the circuit board by vacuum suction, a pair of left and right battery positioning walls that contact the shoulders on the sealing plate side of the secondary battery to position the secondary battery, and a board positioning wall And a substrate holding part having a side wall in a direction perpendicular to the positioned circuit board surface that connects each of the left and right pair of battery positioning wall surfaces;
Urging means for urging the secondary battery, and urging means for bringing the shoulder portions of the secondary battery into contact with the battery positioning wall surface;
When both shoulder portions of the secondary battery abut on the battery positioning wall surface, the circuit board is positioned and held on the substrate positioning wall surface, the secondary battery sealing plate, and the side wall. Using a mold configured so that the space becomes a resin-filled space,
The resin-filled object is positioned by vacuum-adsorbing the circuit board to the substrate positioning wall surface, the secondary battery is accommodated and held in the battery holding part, and the secondary battery is biased by the biasing means. In the state where both shoulder portions of the secondary battery are in contact with the battery positioning wall surface, the intermediate completion is performed by placing the resin in the mold and filling the resin filling space with resin. A method for manufacturing a battery pack, comprising: obtaining a product .

Connect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering A method,
As the mold,
A battery holding unit for accommodating and holding the secondary battery;
A pair of left and right board positioning wall surfaces for positioning the circuit board by contacting both ends of the circuit board facing the secondary battery, and biasing the circuit board so that the both ends are in contact with the board positioning wall surface Means, a pair of left and right battery positioning walls for positioning the secondary battery in contact with both shoulders on the sealing plate side of the secondary battery, and a pair of left and right substrate positioning walls and a pair of left and right battery positioning A board holding portion having a side wall in a direction perpendicular to the positioned circuit board connecting each of the wall surfaces;
Urging means for urging the substrate holding part to bring the battery positioning wall surface into contact with the shoulders of the secondary battery;
A space surrounded by the circuit board positioned on the substrate positioning wall, the sealing plate of the secondary battery, and the side wall when the battery positioning wall contacts the shoulders of the secondary battery. Using a mold configured to be a resin-filled space,
The circuit board positioning wall is formed by urging the resin-filled object with the urging means.
The battery is held in the battery holding portion, and the substrate holding portion is urged by the urging means so that the battery positioning wall faces the shoulders of the secondary battery. A method of manufacturing a battery pack, wherein the intermediate finished product is obtained by placing the resin in the mold in a state of being made, filling the resin filling space with resin, and performing resin molding .

Connect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering A method,
As the mold,
A battery holder for holding and holding the secondary battery so as to be movable in the direction of separation from the circuit board; and
A pair of left and right board positioning wall surfaces for positioning the circuit board by contacting both ends of the circuit board facing the secondary battery, and biasing the circuit board so that the both ends are in contact with the board positioning wall surface Means, a pair of left and right battery positioning walls for positioning the secondary battery in contact with both shoulders on the sealing plate side of the secondary battery, and a pair of left and right substrate positioning walls and a pair of left and right battery positioning A board holding portion having a side wall in a direction perpendicular to the positioned circuit board connecting each of the wall surfaces;
Urging means for urging the secondary battery, and urging means for bringing the shoulder portions of the secondary battery into contact with the battery positioning wall surface;
When both shoulder portions of the secondary battery abut on the battery positioning wall surface, the circuit board is positioned and held on the substrate positioning wall surface, the secondary battery sealing plate, and the side wall. Using a mold configured so that the space becomes a resin-filled space,
The circuit board is biased by the biasing means to position the resin-filled object on the board positioning wall surface, the secondary battery is accommodated and held in the battery holding portion, and the secondary battery is biased by the biasing means. The resin battery is placed in the mold in a state where both shoulder portions of the secondary battery are in contact with the battery positioning wall surface, and the resin filling space is filled with resin to perform resin molding. A method of manufacturing a battery pack, characterized in that the intermediate finished product is obtained .

Connect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering A method,
As the mold,
A battery holding unit for accommodating and holding the secondary battery;
A pair of left and right substrate positioning grooves for positioning the circuit board by fitting and holding both ends of the circuit board, a pair of left and right positions for positioning the secondary battery by contacting both shoulders on the sealing plate side of the secondary battery A battery holding wall, and a substrate holding portion having a side wall perpendicular to the positioned circuit board that connects the left and right pair of substrate positioning grooves and the left and right pair of battery positioning walls;
Urging means for urging the substrate holding part to bring the battery positioning wall surface into contact with the shoulders of the secondary battery;
A space surrounded by the circuit board positioned in the board positioning groove, the sealing plate of the secondary battery, and the side wall when the battery positioning wall faces the shoulders of the secondary battery. Using a mold configured to be a resin-filled space,
The resin-filled object is positioned in the circuit board positioning groove and the secondary circuit board.
In the state where the battery is accommodated and held in the battery holding portion, the substrate holding portion is urged by the urging means, and the battery positioning wall surfaces are in contact with the shoulder portions of the secondary battery, the mold The intermediate finished product is obtained by placing the resin inside and filling the resin filling space with resin to perform resin molding.
A battery pack manufacturing method characterized by the above .

Connect the circuit board with the external connection terminal on one side to the sealing plate of the secondary battery formed in a flat rectangle by the connecting member, and arrange the circuit board with a gap so that the other side faces the sealing plate The resin-filled object is formed, the secondary battery and the circuit board are positioned at predetermined positions and placed in the mold, and the resin-filled object is placed in the resin-filled space between the secondary battery and the circuit board. Manufacturing a battery pack in which an intermediate finished product is formed by integrating a secondary battery and a circuit board by resin molding to fill the resin, and at least external connection terminals of the intermediate finished product are exposed to the outside to form an exterior covering A method,
As the mold,
A battery holder for holding and holding the secondary battery so as to be movable in the direction of separation from the circuit board; and
A pair of left and right substrate positioning grooves for positioning the circuit board by fitting and holding both ends of the circuit board, a pair of left and right positions for positioning the secondary battery by contacting both shoulders on the sealing plate side of the secondary battery A battery holding wall, and a substrate holding portion having a side wall perpendicular to the positioned circuit board that connects the left and right pair of substrate positioning grooves and the left and right pair of battery positioning walls;
Urging means for urging the secondary battery, and urging means for bringing the shoulder portions of the secondary battery into contact with the battery positioning wall surface;
When both shoulder portions of the secondary battery abut on the battery positioning wall surface, the circuit board is positioned and held on the substrate positioning wall surface, the secondary battery sealing plate, and the side wall. Using a mold configured so that the space becomes a resin-filled space,
The resin-filled object is positioned in the circuit board positioning groove, the secondary battery is accommodated and held in the battery holding portion, and the secondary battery is urged by the urging means. The intermediate finished product is obtained by placing in the mold in a state where both shoulder portions of the battery are in contact with the battery positioning wall surface, filling the resin filling space with resin, and performing resin molding.
A battery pack manufacturing method characterized by the above .

A sealing plate of a secondary battery formed in flat rectangular, biases the circuit substrate provided with the external connection terminal on one surface while arranged at intervals gap, in the direction of separating the circuit board from the secondary battery by an elastic A mold in which an internal space is formed in which the dimension from the bottom surface of the secondary battery to the formation surface of the external connection terminal is regulated by connecting the circuit board to the secondary battery by the connecting member The resin-filled object is placed against the urging force of the connecting member, and resin molding is performed to fill the resin in a gap separating the secondary battery and the circuit board, thereby forming the secondary battery and the circuit board. A method of manufacturing a battery pack, comprising: forming an outer covering by forming at least an external connection terminal of the intermediate finished product to the outside.

The battery according to any one of claims 1 to 8 , wherein an undercut portion is formed in a sealing board of the secondary battery in a circuit board direction, and the resin filled between the circuit board and the secondary battery is engaged with the secondary battery. Pack manufacturing method.

The outer covering is formed of a resin-molded upper molded portion that exposes at least the external connection terminals between the external connection terminal formation surface of the circuit board and the sealing plate of the secondary battery, and the secondary finished product for the intermediate finished product. A secondary molded part is formed by forming a lower molded part formed at a predetermined height on the bottom surface of the battery and a connection molded part that connects the upper molded part and the lower molded part with a short side surface of the secondary battery, The manufacturing method of the battery pack as described in any one of Claims 1-8 which coat | covered the surface, a part of side peripheral part of an upper shaping | molding part and a lower shaping | molding part, and a connection shaping | molding part, and wound the sheet | seat. .

The method of manufacturing a battery pack according to claim 10 , wherein the secondary battery is formed in an elliptical shape in cross section, and the connection molding part is formed so that the arc part at both ends enters a rectangular line surrounding it.

The exterior covering is formed on the external connection terminal forming surface side of the circuit board and / or the bottom surface side of the secondary battery by covering the intermediate finished product with a cylindrical body or a bottomed cylindrical body formed at a predetermined height. The method for producing a battery pack according to any one of claims 1 to 8 , wherein at least an external connection terminal is exposed to the outside at an open end and the resin is filled and molded.

The battery pack according to any one of claims 1 to 8 , wherein the exterior covering is formed such that a predetermined portion including the external connection terminal is externally exposed and coated with a resin on the entire outer peripheral surface of the intermediate finished product. Method.

A portion in contact with Katsuden sites exposed outside the resin charging object or intermediate product in the mold used in the primary molding and the secondary molding is formed by being subjected to insulating covering according to claim 1 to 13 any one The manufacturing method of the battery pack of description.