JPH10106516A - Conductive terminal and polymer sheet package battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight, high energy density battery which is packaged with a polymeric sheet, is easily manufacturable, and excels in reliance, stability, and safety. SOLUTION: An electroconductive terminal is formed in a flat laminate consisting of conductive sheets 1 and a resin sheet 2 having a hole in the center, wherein the material of the sheet 2 is a resin capable of fusion attachment or adhesion to a polymeric sheet package material. A metal-based conductive/ insulating polymeric admixture 3 to shut of electric continuity accompanied by a resistance increment at a high temp. is laminated on the conductive sheets 1 of this terminal. An intended battery is fabricated by embedding the obtained conductive terminals in a polymeric sheet package.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive terminal provided on an electrode of a battery packaged with a polymer sheet packaging material, and a battery using the conductive terminal.

[0002]

2. Description of the Related Art At present, high energy density batteries have been developed as power supplies for various portable devices such as personal computers, mobile phones and video cameras. As this battery, a lithium ion secondary battery, a nickel hydride battery, a nickel cadmium battery, etc., which can be repeatedly used for charging and discharging, are used.
In particular, lithium ion secondary batteries are characterized by high energy density, and are being actively developed because the batteries can be reduced in size and weight.

Conventionally, a lithium ion secondary battery uses an electrolytic solution as an ion transfer medium between electrodes, and usually has a structure in which a laminate of an electrode and a porous separator is impregnated with the electrolytic solution. As described above, in a battery using an electrolytic solution, a heavy metal material is used for a battery package in order to prevent liquid leakage. On the other hand, batteries using a solid electrolyte as an ion transfer medium
Compared to a conventional battery using an electrolyte as an ion transfer medium, there is virtually no liquid leakage, improving the reliability and safety of the battery, making it easier to form thin films and laminates, and having a high degree of freedom in battery form. In addition, simplification of the package and weight reduction are expected.

A battery using a solid electrolyte is formed into a predetermined shape by laminating a sheet-like electrode and a solid electrolyte or a laminate in which a polymer solid electrolyte layer is formed by applying a polymer solid electrolyte layer on the surface of an electrode. Can be made. A method of forming each layer of the electrode / polymer solid electrolyte / electrode by coating has also been proposed. As described above, since a method such as sheet lamination or coating can be adopted, it is expected that the production process is excellent in mass productivity. Further, since the liquid leakage that can occur in the conventional electrolyte battery does not substantially occur, the production process can be easily controlled, and a higher voltage is expected by series connection and lamination of the electrode / solid electrolyte / electrode laminate.

The above-described solid electrolyte battery is usually used by being packaged with a laminated polymer sheet in which a resin sheet and a metal sheet are laminated. In order to use this packaged battery, it is necessary to provide a current extraction terminal from the electrode inside the package to the outside of the package, and the battery is usually constructed with a structure in which the electrode terminal is sandwiched by the sealing part of the polymer sheet and fused. Is done. However, this structure has a structure in which the electrode terminals protrude from the package surface, which hinders miniaturization of the battery. A battery having a structure in which a hole is provided in a part of a package and the current collector surface of the electrode stack is closely attached to the hole has been proposed (US Pat. No. 5,478,668). However, in the batteries having these structures, there is a problem that leakage occurs inside and outside the battery, disconnection of the electrode terminals during the process, poor conduction, and the like at the electrode terminal sealing portion of the package, thereby lowering the performance of the lithium secondary battery.

Further, when the battery is erroneously overcharged or when the electrode terminals are short-circuited in a charged state, heat is generated inside the electrode, which may impair the safety of the battery. In order to ensure safety in this case, a PTC element (Positive Tem
perature Coefficient element) to provide a function to prevent conduction of electrodes at high temperatures. Attempts have been made to use this PTC element also in a polymer package battery (US Pat. No. 5,478,668), but there has been a problem that connection processing to an electrode laminate is complicated.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a conductive terminal which is excellent in reliability, stability and safety, and which can make a battery smaller, and a battery using the same. I do.

[0008]

Means for Solving the Problems The present inventors have conducted research on a package material and a structure of a solid battery mainly using a solid electrolyte, and completed the present invention. That is, the present invention
(1) A laminate formed by laminating a conductive sheet and a resin sheet having a hole in the center, and the resin sheet is made of a resin that can be fused or adhered to a polymer sheet package material. (2) a conductive sheet, wherein the conductive sheet is a metal layer and metallic conductive particles capable of interrupting conduction of the conductive terminal when electric resistance rises sharply at a certain temperature or higher. (1) The conductive terminal of the above (1), which is a sheet having a structure in which the resin layer is laminated with a mixture layer of a / insulating polymer; A structure in which a mixture layer of metallic conductor particles / insulating polymer is laminated on a conductive sheet, the electric resistance of which rises sharply at a certain temperature or higher, and can interrupt the conduction of the conductive terminal. Characterized by (4) In a battery packaged with a polymer sheet package material, the conductive terminal of (1), (2) or (3) is buried in an opening provided in the package material. Is a polymer sheet package battery joined to an electrode or an electrode current collector.

Hereinafter, the conductive terminal and the battery of the present invention will be described. The present invention relates to a conductive terminal installed on an electrode or an electrode current collector of a battery packaged with a polymer sheet packaging material for performing electron transfer outside the package. The conductive terminal of the present invention is a flat conductive terminal in which a conductive sheet and a resin sheet having a hole in a central portion are laminated as shown in FIGS. 1 and 2, and the resin sheet is laminated. No, it has a conductive portion with a sufficient area to allow the current to be extracted to the outside. In the present invention, having a hole in the central portion means that when laminated, the conductive sheet has a structure in which a resin sheet is laminated on a peripheral portion of the conductive sheet, and has a sufficient area for conducting electric current to the outside. The presence of a hole at a position where a conductive part can be provided does not necessarily mean that the hole is located at the center, but it is preferable that the hole be located at the center from the viewpoint of ease of forming the conductive terminal. The hole in the present invention only needs to be able to form a conductive portion having a sufficient area from which a current can be extracted to the outside, and can take various shapes such as a circle, an ellipse, and a square. Further, the resin sheet laminated on the periphery of the conductive sheet constituting the conductive terminal needs to be able to adhere or fuse with the polymer sheet package material. The resin sheet may be smaller than the conductive sheet as long as the resin sheet can be joined to the polymer sheet package material, but is larger than the conductive sheet and is laminated in a state protruding from the periphery of the conductive sheet. Is preferred. The conductive terminals and the polymer sheet package material are joined by the adhesive or fusible resin sheet to form a package, which can prevent internal and external leaks, and also allows the electrodes or the electrode current collectors in the polymer sheet package to be prevented. Conductive bonding between the body and the conductive terminal becomes possible, and current can be taken out of the package.

The conductive terminal of the present invention can have various shapes such as a disk shape, an elliptical plate shape, and a square plate shape. The conductive terminal is provided on the upper surface and the lower surface portion or the side surface portion of the battery package. Can be arranged to form a battery. Since the shape of the conductive terminal of the present invention is a flat shape, the entire battery package is not bulky even when installed, so that the volume energy density of the battery can be increased.

[0011] The conductive terminal of the present invention is provided after the conductive terminal is buried in an opening provided in the package material in advance.
Either a method in which the electrode laminate is placed in a package material and sealing, or a method in which the electrode laminate is sealed in a package material having an opening and then a conductive terminal is embedded in the opening provided in advance. Therefore, the resin sheet that can be fused or adhered, which is used for the conductive terminal, needs to have a shape large enough to cover the opening of the package material.

[0012] The conductive terminal of the present invention is a metallic conductive particle / insulating polymer PT capable of interrupting conduction of the conductive terminal by rapidly increasing the electric resistance at a certain temperature or higher.
By adopting a structure in which a mixture layer made of the C element material is laminated, a current interrupting function at a high temperature of the conductive terminal can be provided. By interrupting the current at this high temperature, for example, abnormal operations such as overdischarge and external short circuit can be prevented, so that the safety of the battery can be improved. This PTC element material usually has a structure in which conductive particles and fillers are dispersed in a resin binder. By utilizing the fact that the thermal expansion coefficient of the resin binder is larger than that of the conductive particles, conduction between the conductive particles is interrupted at high temperatures. It works by doing.

As a method of manufacturing a structure in which the mixture layer made of the PTC element material is laminated, a method of using the laminate of the mixture layer made of the PTC element material and the metal layer as a conductive sheet, And a method of laminating a mixture layer on a conductive sheet on which no resin sheet is laminated. As a specific example of the structure of the conductive terminal of the present invention, a laminated structure of a conductive sheet / a donut-shaped resin sheet, a laminated structure of a metal layer / mixture layer (conductive sheet) / a donut-shaped resin sheet shown in FIG. 2, a laminated structure of a conductive sheet / a donut type resin sheet / a mixture layer / a conductive sheet. In the laminated structure shown in FIG. 2, the thickness of the mixture layer to be laminated is equal to or greater than the thickness of the donut-shaped resin sheet, and preferably the same. From the viewpoint of miniaturization of the battery, the thickness of the conductive sheet and the resin sheet constituting the conductive terminal is preferably small. In order to maintain the airtightness of the battery using the terminal, at least one of the conductive sheets in the above structure is desirably a continuous body having no through-hole.

The conductive sheet used for the conductive terminal of the present invention includes a metal sheet such as a stainless steel sheet, a carbon sheet, a dispersion in which conductive particles are mixed and dispersed in a resin or ceramic, a conductive polymer sheet, and the above-mentioned mixture. And a laminate of a metal layer and a metal layer. Further, the material of the resin sheet needs to be able to be fused or adhered to the package material. Specific examples include thermoplastic resins such as polyethylene, polypropylene, ionomer resin, ethylene / vinyl alcohol copolymer, nylon, aromatic polyamide, aromatic polyester, polyphenylene oxide, polyoxymethylene, and polycarbonate, and styrene / butadiene copolymer. Thermoplastic resin or thermosetting resin having an adhesive portion such as an adhesive such as latex or epoxy. Further, a sheet laminated with these resins, for example, polyethylene / polyethylene terephthalate / polyethylene or the like can also be used. In this case, the resin sheet to be laminated is not limited to the above resin.

As a method for producing the conductive terminal of the present invention, for example, a method of laminating a resin sheet on a conductive sheet, a method of coating a resin layer on a part of the conductive sheet, and a method of forming a conductive sheet on a resin sheet Method. Further, in the package battery using the conductive terminal of the present invention, the battery is operated by conductively bonding the conductive terminal and the electrode or the electrode current collector. Method, conductive adhesive, spot welding, welding method such as ultrasonic welding, and the like. In order to improve the continuity of the direct contact, an uneven shape can be provided on a part of the electrode laminate or the conductive terminal.

In the polymer sheet package battery of the present invention, since the conductive terminals are embedded in the package material,
A high energy density battery can be manufactured without being bulky. Further, the battery of the present invention can be used as a single-cell or multi-cell pack battery. Further, the conductive terminal of the present invention is easy to manufacture and rich in mass productivity, and can be applied to various battery forms. The battery of the present invention is particularly suitable for a lithium-ion battery, but is not limited thereto, a lead battery, an alkaline battery,
It can be applied to various batteries such as nickel-metal hydride batteries.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

[0018]

Example 1 A stainless sheet disk (10 μm thick) punched to a diameter of 19 mm, an outer diameter of 30 mm, and an inner diameter of 15 mm
Polyethylene / polyethylene terephthalate / polyethylene laminated sheet disk cut into pieces (thickness: 50 μm)
Are laminated with the centers of the polytetrafluoroethylene sheets (thickness: 50 μm) and hot roll pressed (temperature: 130 ° C.) while being sandwiched between the polytetrafluoroethylene sheets (thickness: 50 μm).
The stainless sheet laminate was taken out. This laminate is the conductive terminal shown in FIG.

The polyethylene / aluminum / polyethylene terephthalate laminated sheet is processed into a bag shape (100 mm
× 105 mm, heat-sealing two sides, 3 mm wide, 1
After the sides were folded back and one side was open), the center of the bag was punched out with a diameter of 20 mm, and holes serving as openings were provided (two holes were formed in the package). After arranging two conductive terminals in the hole of the package, a hot roll press is performed with a polytetrafluoroethylene sheet (width 92 mm, length 150 mm) sandwiched between the conductive terminals inside the package. Was buried in a package bag. LiCoO ₂ sheet (width 90 mm, binder polyvinylidene fluoride, film thickness 110 μm, one-sided coating, aluminum current collector), needle coke sheet (width 90 mm, styrene-butadiene latex as binder, film thickness 125 μm)
m single-sided coating, copper current collector) for the positive and negative electrodes, respectively.
An electrode laminate was prepared by laminating a polyvinylidene fluoride-hexafluoropropylene copolymer foam sheet with a solid electrolyte (92 mm wide) impregnated with an electrolytic solution. The laminated sheet was bent four times every 100 mm, and processed into a structure having an aluminum current collector on the upper surface and a copper current collector on the lower surface of the folded laminate. After inserting the folded laminate into the polymer package bag, the insertion opening was heat-sealed with a width of 3 mm to produce a battery package. As a result of connecting and disconnecting the conductive terminals on the upper and lower surfaces of the battery to a charger / discharger, the initial discharge capacity was 1.1 Ah and the average voltage was 3.6 V.
(3.96 Wh), and repeated charge / discharge was possible.

[0020]

Example 2 Using the same stainless steel sheet disk and polyethylene laminated sheet disk as used in Example 1, a PTC sheet (diameter 10 mm, thickness about 100 μm) was placed at the center of the polyethylene laminated sheet disk. Stainless steel discs were laminated on the upper and lower surfaces to form a stainless steel / polyethylene-PTC element / stainless steel sheet, and a hot roll press was performed in the same manner as in Example 1 to produce a laminate. This laminate is connected to a conductive terminal (FIG. 2).
Used as

After the conductive terminals were arranged in the two holes of the polyethylene / aluminum / polyethylene terephthalate laminated sheet perforated bag used in Example 1, a polytetrafluoroethylene sheet (width 92 mm, length 150 mm) was placed inside the package. Then, the conductive terminals were embedded in the package bag by hot roll pressing in a state of sandwiching them. The electrode laminate sheet used in Example 1 was bent four times every 100 mm, and processed into a structure having an aluminum current collector on the upper surface and a copper current collector on the lower surface of the folded laminate. After inserting the folded laminate into the polymer package bag, the insertion opening was heat-sealed with a width of 3 mm to produce a battery package. As a result of connecting and disconnecting the conductive terminals on the upper and lower surfaces of the battery to a charger / discharger, the initial discharge capacity was 1.12 Ah and the average voltage was 3.6.
V (4.0 Wh), and repeated charge / discharge was possible. The battery resistance was measured while the battery was externally heated. As a result, it was found that the resistance rapidly increased at 110 ° C., and that the PTC element was operating.

[0022]

Example 3 A stainless steel sheet (thickness: 10 μm) was punched out to produce a disk having a diameter of 20 mm, and a styrene-butadiene latex was applied to a width of 5 mm around the disk and dried. This disc was used as a conductive terminal (FIG. 1) and processed into a polyethylene / aluminum / polyethylene terephthalate laminated sheet bag shape (100 mm × 120 mm, as in Example 1).
Two of the four sides were heat-sealed with a width of 3 mm, one side was folded back, and one side was open), and the center was punched out with a diameter of 10 mm to provide holes as openings (two holes were formed in the package). Opened). After arranging the two conductive terminals in the hole of the package, the conductive terminals are embedded in the package bag by hot roll pressing with the polytetrafluoroethylene sheet (width: 92 mm, length: 150 mm) sandwiched inside the package. I let it. The electrode laminate sheet used in Example 1 was 100
The laminate was bent four times every mm, and processed into a structure having an aluminum current collector on the upper surface and a copper current collector on the lower surface of the folded laminate. After inserting the folded laminate into the polymer package bag, the insertion opening was heat-sealed with a width of 3 mm to produce a battery package. As a result of charging and discharging by connecting the conductive terminals on the upper and lower surfaces of the battery to the charging / discharging machine, the initial discharging capacity is 1.12 Ah, the average voltage is 3.6 V (4.0 Wh), and the charging and discharging can be repeated. Met.

[0023]

According to the present invention, the conductive terminal and the polymer sheet package battery can be manufactured in a high energy density without being bulky because the conductive terminal is embedded in the package material.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a conductive terminal of the present invention.

FIG. 2 is a longitudinal sectional view showing an example of a conductive terminal of the present invention.

FIG. 3 is a partial longitudinal sectional view showing a mounting portion of a polymer package battery to which a conductive terminal of the present invention is mounted.

[Explanation of symbols]

 1. 1. Conductive sheet Resin sheet 3. 3. PTC sheet 4. Polymer package material 5. Electrode or electrode current collector Aperture

Claims (4)

[Claims] 1. A resin which is formed by laminating a conductive sheet and a resin sheet having a hole in a central portion, wherein the resin sheet is capable of being fused or adhered to a polymer sheet package material. A conductive terminal, comprising: 2. An electrically conductive sheet comprising a metallic layer and a mixture of metallic conductive particles / insulating polymer capable of interrupting conduction of a conductive terminal by rapidly increasing electric resistance at a certain temperature or higher. The conductive terminal according to claim 1, which is a sheet having a structure in which layers are laminated. 3. The electric resistance rapidly increases at a certain temperature or higher on the conductive sheet on which the resin sheet is not laminated, on the resin sheet laminating side of the conductive terminal of claim 1, and the conduction of the conductive terminal is increased. Metallic conductive particles that can be blocked
A conductive terminal having a structure in which a mixture layer of an insulating polymer is laminated. 4. A battery packaged with a polymer sheet package material, wherein the conductive terminal according to claim 1, 2 or 3 is embedded in an opening provided in the package material, and the conductive sheet of the conductive terminal is A polymer sheet package battery bonded to an electrode or an electrode current collector.