JP2019036540A - Battery, manufacturing method thereof, metal terminal with adhesive film for metal terminal, and winding body for the adhesive film for metal terminal - Google Patents

Abstract

To provide a battery which appropriately suppresses opening of a packaging material in a portion where an adhesive film is positioned, even in a case where an inner pressure of a battery rises.SOLUTION: The present invention relates to a battery comprising at least: a battery element including a cathode, an anode and an electrolyte; a packaging material in which the battery element is encapsulated; and a metal terminal which is electrically connected to the cathode and the anode and extends to the outside of the packaging material. An adhesive film for metal terminal is disposed between the metal terminal and the packaging material. The adhesive film for metal terminal includes a first polyolefin layer, a substrate film containing polyethylenenaphthalate and a second polyolefin layer in this order. At least one of the first polyolefin layer and the second polyolefin layer contains acid modified polyolefin. In the battery, an angle θ formed from a Ydirection that is a maximal in-plane orientation direction of a naphthalene ring contained in the substrate film and an extension direction of the metal terminal to the outside of the packaging material is equal to or larger than 45° and equal to or smaller than 135°.SELECTED DRAWING: None

Description

  The present invention relates to a battery, a manufacturing method thereof, a metal terminal with an adhesive film for a metal terminal, and a wound body of the adhesive film for the metal terminal.

  Conventionally, various types of batteries have been developed, and packaging materials are indispensable members for sealing battery elements such as electrodes and electrolytes in all batteries. Conventionally, metal packaging materials have been widely used as battery packaging, but in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries are required to have various shapes. At the same time, there is a demand for reduction in thickness and weight. However, conventionally used metal packaging materials have the disadvantages that it is difficult to follow the diversification of shapes and that there is a limit to weight reduction.

  Therefore, in recent years, as a packaging material that can be easily processed into various shapes and can be reduced in thickness and weight, there is a film-like laminate in which a base layer / barrier layer / heat-sealable resin layer are sequentially laminated. It has been proposed (see, for example, Patent Document 1). When such a film-shaped packaging material is used, the peripheral portion of the packaging material is heat-sealed in a state where the heat-fusible resin layers located in the innermost layer of the packaging material are opposed to each other. The battery element is sealed. A metal terminal protrudes from the heat-sealed portion of the packaging material, and the battery element sealed by the packaging material is electrically connected to the outside by the metal terminal electrically connected to the electrode of the battery element. . That is, at the heat-sealed portion of the packaging material, the metal terminal is formed so as to protrude outside the packaging material while being sandwiched between the heat-fusible resin layers. Since the metal terminal and the heat-fusible resin layer are formed of different materials, the sealing performance of the battery element tends to be low at the interface between the metal terminal and the heat-fusible resin layer. For this reason, a technique is known in which an adhesive film is disposed at the interface portion between the metal terminal and the heat-fusible resin layer to suppress a decrease in sealing performance at the interface portion between the metal terminal and the heat-fusible resin layer. ing.

  For example, Patent Document 2 discloses an adhesive film for sealing a lithium battery metal terminal part in which an acid-modified polyolefin layer is formed on both sides of a biaxially stretched polyethylene naphthalate film via an adhesion promoter layer made of an isocyanate component. It is disclosed.

JP 2001-202927 A Patent No. 4440573

  In the adhesive film disclosed in Patent Document 2, a biaxially stretched polyethylene naphthalate film having a high water vapor barrier property and high mechanical strength functions as a substrate, and an adhesion promoter layer is provided on both sides of the substrate. And a polyolefin layer is laminated. Therefore, by sealing the metal terminal and the heat-fusible resin layer of the packaging material through the adhesive film, the adhesion between the metal terminal and the heat-fusible resin layer is improved, and further, the metal terminal And the barrier layer laminated on the packaging material can be prevented from being short-circuited. Moreover, it has the advantage that it is excellent also in heat resistance by using a biaxially stretched polyethylene naphthalate film.

  In recent years, the use of batteries has been wide-ranging. For example, the internal pressure of a battery packaging material may increase depending on what is used in a high temperature environment and the type of electrolyte. For example, when the battery is exposed to a high temperature, the organic solvent used in the electrolytic solution may be decomposed to generate gas, which may increase the internal pressure. Further, due to charging due to overvoltage, discharging with excessive current, etc., the temperature in the battery rises continuously, causing the battery reaction to run away, and the internal pressure of the packaging material may rise.

  As a result of repeated studies by the inventors, when the internal pressure of the battery packaging material increases, a force is applied in the thickness direction of the adhesive film located between the packaging material and the metal terminal, and the adhesive film is positioned. It has been found that there is a possibility that the heat-sealed part at the periphery of the battery may be unsealed.

  Under such circumstances, the main object of the present invention is to provide a battery in which the opening of the packaging material in the portion where the adhesive film is located is suitably suppressed even when the internal pressure of the battery increases. To do. Furthermore, this invention also aims at providing the manufacturing method of the said battery.

  The inventors of the present invention have intensively studied to solve the above problems. As a result, it has been found that a battery having the following configuration appropriately suppresses the opening of the packaging material at the portion where the adhesive film is located even when the internal pressure of the battery increases. The present invention has been completed by further studies based on such knowledge.

A battery element including at least a positive electrode, a negative electrode, and an electrolyte; a packaging material that seals the battery element; and a metal terminal that is electrically connected to each of the positive electrode and the negative electrode and extends outside the packaging material. A battery comprising:
Between the metal terminal and the packaging material, an adhesive film for metal terminal is disposed,
The metal terminal adhesive film includes a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
A battery in which an angle θ between a Y _max direction and a direction in which the metal terminal extends to the outside of the packaging material, measured by the following method, is 45 ° or more and 135 ° or less.

(Measurement method in Y _max direction)
The measuring method in the Y _max direction of the adhesive film for metal terminals is 0 ° in the direction perpendicular to the thickness direction with respect to the surface of the substrate film by the polarization measurement of the single reflection ATR method of Fourier transform infrared spectroscopy. When infrared absorption spectra in 18 directions are acquired from 10 to 170 ° in 10 ° increments, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum in each of the 18 directions is the absorption peak at 1181 cm ⁻¹ . A value Y is calculated by dividing by the intensity Y ₁₁₈₁ , and the direction in which the maximum value Y _max of each value Y is obtained is defined as the Y _max direction.

That is, this invention provides the invention of the aspect hung up below.
Item 1. A battery element including at least a positive electrode, a negative electrode, and an electrolyte; a packaging material that seals the battery element; and a metal terminal that is electrically connected to each of the positive electrode and the negative electrode and extends outside the packaging material. A battery comprising:
Between the metal terminal and the packaging material, an adhesive film for metal terminal is disposed,
The metal terminal adhesive film includes a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
A battery in which an angle θ between a Y _max direction and a direction in which the metal terminal extends to the outside of the packaging material, measured by the following method, is 45 ° or more and 135 ° or less.
The measurement method in the Y _max direction is a step of 10 ° from 0 ° to 170 ° in the direction perpendicular to the thickness direction on the surface of the base film by polarization measurement using a single reflection ATR method of Fourier transform infrared spectroscopy. When the infrared absorption spectrum in 18 directions is acquired, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum is divided by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ in each of the 18 directions. The value Y is calculated, and the direction in which the maximum value Y _max among the values Y is obtained is defined as the Y _max direction.
Item 2. Item 2. The battery according to Item 1, wherein the base film of the adhesive film for metal terminals has a thickness of 10 μm to 50 μm.
Item 3. Item 3. The battery according to Item 1 or 2, wherein the first polyolefin layer and the second polyolefin layer of the adhesive film for metal terminal contain acid-modified polyolefin.
Item 4. Item 4. The battery according to any one of Items 1 to 3, wherein thicknesses of the first polyolefin layer and the second polyolefin layer of the adhesive film for metal terminals are 5 μm or more and 80 μm or less, respectively.
Item 5. Item 5. The battery according to any one of Items 1 to 4, wherein the metal terminal adhesive film has a thickness of 20 μm to 200 μm.
Item 6. Item 6. The battery according to any one of Items 1 to 5, wherein the packaging material is composed of a laminate including at least a base material layer, a barrier layer, and a heat-fusible resin layer in this order.
Item 7. A battery element including at least a positive electrode, a negative electrode, and an electrolyte, a packaging material that seals the battery element, and a metal terminal that is electrically connected to each of the positive electrode and the negative electrode and protrudes outside the packaging material A method of manufacturing a battery comprising:
A step of arranging an adhesive film for metal terminals between the metal terminal and the packaging material;
As the adhesive film for metal terminals, a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer are provided in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
A method for producing a battery, wherein an angle θ between a Y _max direction and a direction in which the metal terminal extends to the outside of the packaging material, measured by the following method, is 45 ° or more and 135 ° or less.
The measurement method in the Y _max direction is a step of 10 ° from 0 ° to 170 ° in the direction perpendicular to the thickness direction on the surface of the base film by polarization measurement using a single reflection ATR method of Fourier transform infrared spectroscopy. When the infrared absorption spectrum in 18 directions is acquired, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum is divided by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ in each of the 18 directions. The value Y is calculated, and the direction in which the maximum value Y _max among the values Y is obtained is defined as the Y _max direction.
Item 8. It is a metal terminal with an adhesive film for metal terminals in which an adhesive film for metal terminals is attached to a metal terminal of a battery,
The metal terminal adhesive film includes a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
When the metal terminal is attached to the battery, the angle θ formed by the direction extending outside the battery and the Y _max direction of the metal terminal adhesive film measured by the following method is 45 ° or more and 135 °. The metal terminal with an adhesive film for a metal terminal, wherein the metal terminal adhesive film is attached to the metal terminal so as to be as follows.
The measurement method in the Y _max direction is a step of 10 ° from 0 ° to 170 ° in the direction perpendicular to the thickness direction on the surface of the base film by polarization measurement using a single reflection ATR method of Fourier transform infrared spectroscopy. When the infrared absorption spectrum in 18 directions is acquired, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum is divided by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ in each of the 18 directions. The value Y is calculated, and the direction in which the maximum value Y _max among the values Y is obtained is defined as the Y _max direction.
Item 9. At least a positive electrode, a negative electrode, and an adhesive film for a metal terminal interposed between a metal terminal electrically connected to the positive electrode and the negative electrode of a battery element having an electrolyte and a packaging material for sealing the battery element A winding body of
The metal terminal adhesive film includes a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
Adhesion for metal terminals, in which an angle θ between the Y _max direction and the direction orthogonal to the winding direction of the winding body of the adhesive film for metal terminals, measured by the following method, is 45 ° or more and 135 ° or less. Of rolled film.
The measurement method in the Y _max direction is a step of 10 ° from 0 ° to 170 ° in the direction perpendicular to the thickness direction on the surface of the base film by polarization measurement using a single reflection ATR method of Fourier transform infrared spectroscopy. When the infrared absorption spectrum in 18 directions is acquired, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum is divided by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ in each of the 18 directions. The value Y is calculated, and the direction in which the maximum value Y _max among the values Y is obtained is defined as the Y _max direction.

  ADVANTAGE OF THE INVENTION According to this invention, even when the internal pressure of a battery rises, the battery by which the opening of the packaging material in the part in which the adhesive film is located was suppressed suitably can be provided. Furthermore, according to this invention, the manufacturing method of the said battery and the metal terminal with the adhesive film for metal terminals can also be provided.

It is a schematic plan view of the battery of the present invention. FIG. 2 is a schematic cross-sectional view taken along line A-A ′ of FIG. 1. FIG. 2 is a schematic cross-sectional view taken along line B-B ′ in FIG. 1. It is a schematic sectional drawing of the adhesive film for metal terminals used for the battery of this invention. It is a schematic sectional drawing of the packaging material used for the battery of this invention. It is a schematic diagram for demonstrating preparation of the battery for a test. Schematic diagram for explaining the angle θ formed by the Y _max direction which is the maximum in-plane orientation direction of the naphthalene ring contained in the base film of the adhesive film for metal terminals and the direction in which the metal terminals extend to the outside of the packaging material It is. It is a schematic diagram for demonstrating the opening test of a packaging material. It is a schematic diagram of the metal terminal with an adhesive film for metal terminals of the present invention.

  The battery of the present invention includes at least a battery element including a positive electrode, a negative electrode, and an electrolyte; a packaging material that seals the battery element; and the positive electrode and the negative electrode that are electrically connected to each other. The battery includes a metal terminal extending outward.

  In the battery of the present invention, an adhesive film for a metal terminal is disposed between the metal terminal and the packaging material. The metal terminal adhesive film includes a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer in this order, at least one of the first polyolefin layer and the second polyolefin layer being Including acid-modified polyolefin.

Furthermore, in the battery of the present invention, the angle θ between the Y _max direction of the adhesive film for metal terminals and the direction in which the metal terminals extend to the outside of the packaging material, measured by the following method, is 45 ° or more and 135. It is characterized by being less than °.

(Measurement method in Y _max direction)
The measuring method in the Y _max direction of the adhesive film for metal terminals is 0 ° in the direction perpendicular to the thickness direction with respect to the surface of the substrate film by the polarization measurement of the single reflection ATR method of Fourier transform infrared spectroscopy. When infrared absorption spectra in 18 directions are acquired from 10 to 170 ° in 10 ° increments, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum in each of the 18 directions is the absorption peak at 1181 cm ⁻¹ . A value Y is calculated by dividing by the intensity Y ₁₁₈₁ , and the direction in which the maximum value Y _max of each value Y is obtained is defined as the Y _max direction.

  Hereinafter, the battery of the present invention and the manufacturing method thereof will be described in detail.

  In the present specification, the numerical range indicated by “to” means “above” or “below”. For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

The battery 10 of the present invention includes a battery element 4 including at least a positive electrode, a negative electrode, and an electrolyte; a packaging material 3 that seals the battery element 4; 3 and a metal terminal 2 projecting to the outside. In the battery 10 of the present invention, a metal terminal adhesive film 1 described later is disposed between the metal terminal 2 and the packaging material 3. That is, the battery 10 of the present invention can be manufactured by a method including a step of disposing the metal terminal adhesive film 1 between the metal terminal 2 and the packaging material 3. In the production of the battery of the present invention, the metal terminal adhesive film 1 has an angle θ of 45 ° or more formed by the Y _max direction and the direction in which the metal terminal extends to the outside of the packaging material, as measured by the above method. The one that is 135 ° or less is used.

  Specifically, when the battery element 4 including at least a positive electrode, a negative electrode, and an electrolyte is sealed with the packaging material 3, the metal terminal adhesive film 1 is placed in a state where the metal terminal 2 protrudes outward. It is interposed between the metal terminal 2 and the heat-fusible resin layer 35. At this time, the metal terminal adhesive film 1 is disposed between the metal terminal 2 and the packaging material 3 so that the angle θ is 45 ° or more and 135 ° or less. The flange portion of the packaging material 3 (the region where the heat-fusible resin layers 35 are in contact with each other and the peripheral portion 3a of the packaging material) can be formed on the periphery of the battery element 4 so that the flange portion is thermally fused. The heat-resistant resin layers 35 are heat-sealed, and the battery element 4 is sealed with the packaging material 3 to obtain a battery.

Moreover, in the battery 10 of this invention, you may arrange | position the metal terminal 5 with the adhesive film 1 for metal terminals to which the adhesive film 1 for metal terminals was previously attached to the metal terminal 2 between the upper and lower packaging materials 3. FIG. In the metal terminal 5 with the adhesive film for metal terminals, the direction x extending to the outside of the battery when the metal terminal 2 is attached to the battery (direction x corresponding to the direction in which the metal terminal extends to the outside of the packaging material) And the adhesive film 1 for metal terminals is attached to the metal terminal 2 so that the angle θ formed by the Y _max direction is 45 ° or more and 135 ° or less (see FIG. 9). The present invention can also provide such a metal terminal with an adhesive film for a metal terminal.

  The battery of the present invention may be either a primary battery or a secondary battery, but is preferably a secondary battery. The type of secondary battery is not particularly limited. For example, lithium ion battery, lithium ion polymer battery, lead storage battery, nickel / hydrogen storage battery, nickel / cadmium storage battery, nickel / iron storage battery, nickel / zinc storage battery, silver oxide / A zinc storage battery, a metal air battery, a polyvalent cation battery, a capacitor, a capacitor, etc. are mentioned. Among these secondary batteries, a lithium ion battery and a lithium ion polymer battery are preferable.

Metal terminal adhesive film The metal terminal adhesive film used in the battery of the present invention will be described in detail.

  The adhesive film for metal terminals is disposed between a metal terminal electrically connected to the electrode of the battery element and a packaging material for sealing the battery element. Specifically, for example, as shown in FIGS. 1 to 3, the metal terminal adhesive film 1 seals the battery element 4 and the metal terminal 2 electrically connected to the electrode of the battery element 4. It is arrange | positioned between the packaging materials 3 to perform. The metal terminal 2 protrudes outside the packaging material 3, and is sandwiched between the packaging material 3 via the metal terminal adhesive film 1 at the peripheral edge 3 a of the heat-sealed packaging material 3. In the present invention, the heating temperature for heat-sealing the packaging material is usually in the range of about 160 to 190 ° C., and the pressure is usually in the range of about 1.0 to 2.0 MPa.

  The metal terminal adhesive film 1 is provided in order to improve the adhesion between the metal terminal 2 and the packaging material 3. By improving the adhesion between the metal terminal 2 and the packaging material 3, the sealing performance of the battery element 4 is improved. As described above, when the battery element 4 is heat sealed, the battery element is sealed so that the metal terminal 2 electrically connected to the electrode of the battery element 4 protrudes outside the packaging material 3. . At this time, the metal terminal 2 formed of metal and the heat-fusible resin layer 35 (layer formed of a heat-fusible resin such as polyolefin) located in the innermost layer of the packaging material 3 are formed of different materials. Therefore, when such an adhesive film is not used, the sealing performance of the battery element tends to be low at the interface between the metal terminal 2 and the heat-fusible resin layer 35.

  In the present invention, the metal terminal adhesive film 1 includes a first polyolefin layer 12a, a base film 11 and a second polyolefin layer 12b in sequence, and at least one of the first polyolefin layer 12a and the second polyolefin layer 12b. One is formed of acid-modified polyolefin. In the metal terminal adhesive film 1, the first polyolefin layer 12a and the second polyolefin layer 12b are located on the surfaces on both sides. When the adhesive film 1 for a metal terminal is disposed between the metal terminal 2 and the packaging material 3 of the battery 10 of the present invention, the surface of the metal terminal 2 made of metal and the thermal fusion of the packaging material 3 The adhesive resin layer 35 (a layer formed of a heat-fusible resin such as polyolefin) is bonded via the metal terminal adhesive film 1.

As described later, in the battery of the present invention, as shown in the schematic diagram of FIG. 7, the Y _max direction, which is the maximum in-plane orientation direction of the naphthalene ring contained in the base film 11 of the adhesive film 1 for metal terminals, The angle θ formed by the direction x in which the metal terminal 2 extends to the outside of the packaging material 3 is 45 ° or more and 135 ° or less so that the metal terminal adhesive film 1 is formed between the metal terminal 2 and the packaging material 3. The heat-fusible resin layers 35 of the packaging material 3 are heat-sealed with each other disposed between them. Thereby, also when the internal pressure of a battery rises, opening of the heat-sealing part of the peripheral edge of a battery in the part in which the adhesive film for metal terminals is located is suppressed suitably. That is, when the angle θ is 45 ° or more and 135 ° or less, the Y _max direction that is the maximum in-plane orientation direction of the naphthalene ring included in the base film 11 extends to the outside of the packaging material 3. Nearly perpendicular to the direction x. Since the naphthalene ring has such an orientation, the strength of the base film 11 in the direction x is increased. For this reason, even when the internal pressure of the battery rises and a strong force is applied in the direction x from the inside of the battery, the base film 11 is difficult to cohesively break, and the heat-sealed portion at the periphery of the battery is opened. Can be suitably suppressed.

[Base film 11]
In the adhesive film 1 for metal terminals, the base film 11 is a layer that functions as a support for the adhesive film 1 for metal terminals.

  The base film 11 contains polyethylene naphthalate (PEN). For example, as disclosed in Patent Document 2, PEN has a higher melting point and glass transition point and superior mechanical strength at high temperatures than polyethylene terephthalate (PET), polyolefin, acid-modified polyolefin, and the like. For this reason, even when the adhesive film 1 for metal terminals is heat-sheeted while being sandwiched between the metal terminals 2 and the packaging material 3, the PEN film is difficult to be thinned. In addition, PEN has a lower water vapor permeability and superior water vapor barrier properties than PET.

  As long as the base film 11 contains polyethylene naphthalate (PEN), it may further contain other resins. Examples of other resins include polyesters, epoxy resins, acrylic resins, fluororesins, silicon resins, phenol resins, polyetherimide resins, polyimide resins, polycarbonates, and mixtures and copolymers thereof other than PEN. It is done.

  Specific examples of polyester resins different from PEN include copolymerized polyesters mainly composed of polyethylene terephthalate, polybutylene terephthalate, polybutylene naphthalate, polyethylene isophthalate, and ethylene terephthalate, and mainly composed of butylene terephthalate. Copolyester and the like. The copolymer polyester mainly composed of ethylene terephthalate is a copolymer polyester that polymerizes with ethylene isophthalate mainly composed of ethylene terephthalate (hereinafter, polyethylene (terephthalate / isophthalate)). Abbreviated), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate) And polyethylene (terephthalate / decanedicarboxylate). In addition, as a copolymer polyester mainly composed of butylene terephthalate as a repeating unit, specifically, a copolymer polyester that polymerizes with butylene isophthalate having butylene terephthalate as a repeating unit (hereinafter referred to as polybutylene (terephthalate / isophthalate)). For example), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate and the like. Polyesters different from PEN may be used singly or in combination of two or more.

  In the present invention, the base film 11 is preferably composed of a polyethylene naphthalate (PEN) film from the viewpoint of imparting excellent sealing properties (water vapor barrier properties) between the packaging material and the metal terminal. .

  Moreover, the base film 11 is uniaxially stretched or biaxially stretched. Since the biaxially stretched base film 11 has improved heat resistance by orientation crystallization, it is preferably used as the base film 11.

Furthermore, in the battery of the present invention, the Y _max direction which is the maximum in-plane orientation direction of the naphthalene ring contained in the base film 11 of the metal terminal adhesive film 1 and the metal terminal 2 extend outside the packaging material 3. The metal terminal adhesive film 1 is arranged so that the angle θ formed by the direction x is 45 ° or more and 135 ° or less, and for the force applied when the internal pressure of the battery rises, The intensity | strength with respect to the direction x of the base film 11 of the adhesive film 1 is raised. For this reason, even when the internal pressure of the battery rises and a strong force is applied in the direction x from the inside of the battery, the base film 11 is difficult to agglomerate and is suitably suppressed from opening the packaging material. Is possible. The measurement method in the Y _max direction is as follows.

<Measurement of the maximum in-plane orientation direction (Y _max direction) of the naphthalene ring>
According to the polarization measurement of the single reflection ATR method of Fourier transform infrared spectroscopy (FT-IR), the surface of the base film is perpendicular to the thickness direction and 0 ° (in the direction perpendicular to the thickness direction). An infrared absorption spectrum in 18 directions is acquired in steps of 10 ° from an arbitrary reference direction) to 170 °. Here, the said surface of a base film is a surface which laminates | stacks either a 1st polyolefin layer or a 2nd polyolefin layer. Next, in each of the 18 directions, the value Y is calculated by dividing the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ . Next, the direction in which the maximum value Y _max is obtained among the obtained values Y (18 values) is defined as the Y _max direction. Examples of the measurement conditions of the infrared absorption spectrum include the following conditions. When measuring the maximum in-plane orientation direction (Y _max direction) of the naphthalene ring on the surface of the base film of the adhesive film for metal terminals obtained from the battery, first, the peripheral heat-sealed portion interposing the metal terminals The battery packaging material is removed, and the metal terminal adhesive film is separated from the battery. Next, the first polyolefin layer or the second polyolefin layer can be peeled off and measured as a state in which the base film is exposed. Further, for the metal terminal adhesive film obtained from the metal terminal adhesive film heat sealed to the metal terminal, the maximum in-plane orientation direction (Y _max direction) of the naphthalene ring on the surface of the base film is measured. In the case, the adhesive film for metal terminals is physically separated from the metal terminal, and the first polyolefin layer or the second polyolefin layer is peeled and removed, so that the substrate film can be measured. When the first polyolefin layer or the second polyolefin layer is peeled and removed from the state of the adhesive film for metal terminals, for example, a heated solvent such as xylene is used to dissolve the first polyolefin or the second polyolefin. The base film can be exposed. In addition, since the surface orientation degree of the base film is an index indicating the stretched state of the base film, when the base film is obtained and measured, the first polyolefin layer or the metal terminal adhesive film obtained from the battery or The measured value does not change between when the second polyolefin layer is peeled off and measured with the base film exposed. The surface orientation degree of the base film may be measured by obtaining the base film.

(Infrared absorption spectrum measurement conditions)
Spectrometer: IS10 manufactured by Thermo
Attached device: One-time reflection ATR accessory device (Seagull)
Detector: MCT (Hg Cd Te)
Resolution: 8cm ^-1
IRE: Ge
Incident angle: 30 °
Polarizer: wire-grid, S-polarized light Baseline: 1800 cm ^-1 mean absorption peak intensity of the intensity at 2000 cm ^-1 from Y _765: baseline values from the maximum value of the peak intensity from 760 cm ^-1 in the range of 770 cm ^-1 Subtracted value Absorption peak intensity Y ₁₁₈₁ : A value obtained by subtracting the baseline value from the maximum peak intensity in the range of 1176 cm ⁻¹ to 1186 cm ^−1.

In the battery of the present invention, the Y _max direction which is the maximum in-plane orientation direction of the naphthalene ring contained in the base film 11 of the adhesive film 1 for metal terminals, and the direction x in which the metal terminals 2 extend to the outside of the packaging material 3; Is an angle θ between 45 ° and 135 °, the mechanism that the opening of the packaging material in the portion where the adhesive film is located is preferably suppressed even when the internal pressure of the battery increases. Can be thought of as follows. That is, as described above, when the internal pressure of the battery packaging material increases, a large force is applied from the inside of the battery toward the outside. At this time, there exists a possibility that a packaging material may open in the part in which the adhesive film for metal terminals between a metal terminal and a packaging material is located. As a result of further studies on this point, when the base film of the adhesive film for metal terminals contains polyethylene naphthalate, a force is applied in the direction x in which the metal terminals 2 extend outside the packaging material 3. The base film of the adhesive film for metal terminals was easily peeled in layers, and the phenomenon that the base film of the adhesive film for metal terminals was broken and the battery was opened was found. This is because the naphthalene ring contained in the base film is oriented in the stretching direction (that is, the direction perpendicular to the thickness direction) by stretching during the production of the base film, and the base film has a high strength direction. When a low direction arises and the direction where the intensity | strength of a base film is low approaches the said direction x, it was thought that it originated in the base film being easy to peel in layers.

And when the present inventors further examined, when the adhesive film for metal terminals is arranged between the metal terminal and the packaging material, the above-mentioned angle θ is 45 ° or more and 135 ° or less. By using the film, the Y _max direction, which is the maximum in-plane orientation direction of the naphthalene ring, and the direction x in which the metal terminal 2 extends to the outside of the packaging material 3 are close to a right angle, and the base film breaks in the x direction. It has been confirmed that this is effectively suppressed. Here, the absorption peak intensity Y _{765 at 765} cm ⁻¹ of the infrared absorption spectrum is due to out-of-plane vibration of the group CH, and the absorption peak intensity Y _{1181 at 1181} cm ⁻¹ of the infrared absorption spectrum is the ^value of the naphthalene ring. This is due to vibration.

From the viewpoint of more effectively suppressing the opening of the packaging material in the portion where the adhesive film is located, in the battery of the present invention, the angle θ formed by the Y _max direction and the direction x is set as a lower limit. The upper limit is preferably about 130 ° or less, more preferably about 120 ° or less, and still more preferably about 90 ° or less. The preferable range of the angle θ formed by the Y _max direction and the direction x is about 50 to 130 °, about 50 to 120 °, about 50 to 90 °, about 60 to 130 °, about 60 to 120 °, 60 About 90 degree is mentioned. The direction x in which the metal terminal extends to the outside of the packaging material is usually the length direction of the metal terminal.

  The surface of the base film 11 may be subjected to known easy adhesion means such as corona discharge treatment, ozone treatment, and plasma treatment as necessary.

  The thickness of the base film 11 is not particularly limited, and is preferably about 10 to 50 μm, more preferably 10 to 10 μm from the viewpoint of preventing short circuit while giving excellent sealing properties between the packaging material and the metal terminal. An example is about 30 μm.

[First and second polyolefin layers 12a, 12b]
In the metal terminal adhesive film 1, at least one of the first and second polyolefin layers 12a and 12b is formed of an acid-modified polyolefin. That is, in the present invention, one of the first and second polyolefin layers 12a and 12b is formed of an acid-modified polyolefin and the other is formed of a polyolefin, and the first and second polyolefin layers 12a. , 12b may be formed of an acid-modified polyolefin. The acid-modified polyolefin has a high affinity with a heat-fusible resin such as metal and polyolefin. Polyolefins have a high affinity with heat-sealable resins such as polyolefins. Therefore, by disposing the layer formed of the acid-modified polyolefin on the metal terminal 2 side, excellent adhesion is exhibited at the interface between the metal terminal adhesive film 1, the metal terminal 2, and the heat-fusible resin layer 35. can do.

  The metal terminal adhesive film 1 may be a laminate including a first polyolefin layer 12a, a base film 11 and a second polyolefin layer 12b in sequence. For example, as shown in FIG. It has a laminated structure in which layer 12a / base film 11 / second polyolefin layer 12b are laminated in this order.

  In the first and second polyolefin layers 12a and 12b, the acid-modified polyolefin is not particularly limited as long as it is an acid-modified polyolefin, and preferably includes a polyolefin graft-modified with an unsaturated carboxylic acid or an anhydride thereof. .

  Specific examples of the acid-modified polyolefin include polyethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; homopolypropylene, block copolymer of polypropylene (for example, block copolymer of propylene and ethylene) ), A random or amorphous polypropylene copolymer (for example, a random copolymer of propylene and ethylene), and a terpolymer of ethylene-butene-propylene. Among these polyolefins, polyethylene and polypropylene are preferable.

  The acid-modified polyolefin may be a cyclic polyolefin. For example, the carboxylic acid-modified cyclic polyolefin is a copolymer obtained by copolymerizing a part of the monomer constituting the cyclic polyolefin in place of the α, β-unsaturated carboxylic acid or its anhydride, or α, It is a polymer obtained by block polymerization or graft polymerization of β-unsaturated carboxylic acid or its anhydride.

  The cyclic polyolefin to be acid-modified is a copolymer of an olefin and a cyclic monomer. Examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Is mentioned. Examples of the cyclic monomer that is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, a cyclic alkene is preferable, and norbornene is more preferable. Examples of the constituent monomer include styrene.

  Examples of the carboxylic acid or anhydride thereof used for acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

  When either one of the first and second polyolefin layers 12a and 12b is made of polyolefin, the polyolefin is the same as that exemplified as the above-mentioned acid-modified polyolefin or acid-modified cyclic polyolefin. Can be illustrated.

  Each of the first and second polyolefin layers 12a and 12b may be formed of one kind of resin component alone, or may be formed of a blend polymer in which two or more kinds of resin components are combined. Further, each of the first and second polyolefin layers 12a and 12b may be formed of only one layer, or may be formed of two or more layers by the same or different resin components.

  Furthermore, the first and second polyolefin layers 12a and 12b may each contain a filler as necessary. Since the first and second polyolefin layers 12a and 12b contain a filler, the filler functions as a spacer, so that a short circuit between the metal terminal 2 and the barrier layer 33 of the packaging material 3 is effective. Can be suppressed. The particle size of the filler is about 0.1 to 35 μm, preferably about 5.0 to 30 μm, and more preferably about 10 to 25 μm. Moreover, as content of a filler, it is about 5-30 mass parts with respect to 100 mass parts of resin components which form the 1st and 2nd polyolefin layers 12a and 12b, respectively, Preferably it is about 10-20 mass parts. Can be mentioned.

  As the filler, either inorganic or organic can be used. Examples of inorganic fillers include carbon (carbon, graphite), silica, aluminum oxide, barium titanate, iron oxide, silicon carbide, zirconium oxide, zirconium silicate, magnesium oxide, titanium oxide, calcium aluminate, and calcium hydroxide. , Aluminum hydroxide, magnesium hydroxide, calcium carbonate and the like. Examples of organic fillers include fluorine resin, phenol resin, urea resin, epoxy resin, acrylic resin, benzoguanamine / formaldehyde condensate, melamine / formaldehyde condensate, polymethyl methacrylate cross-linked product, polyethylene cross-linked product, etc. Can be mentioned. Aluminum oxide, silica, fluororesin, acrylic resin, and benzoguanamine / formaldehyde condensate are preferable from the viewpoint of shape stability, rigidity, and content resistance, and spherical aluminum oxide and silica are more preferable among them. As a method for mixing the filler into the resin component forming the polyolefin layer 12, a method of melt-blending both in advance with a Banbury mixer or the like to obtain a master batch, and a method of directly mixing with the resin component Etc. can be adopted.

  Moreover, the 1st and 2nd polyolefin layers 12a and 12b may contain the pigment as needed. As the pigment, various inorganic pigments can be used. As a specific example of the pigment, carbon (carbon, graphite) exemplified for the filler can be preferably exemplified. Carbon (carbon, graphite) is a material generally used in the battery, and there is no risk of elution from the electrolyte. In addition, a sufficient coloring effect can be obtained with an addition amount that has a large coloring effect and does not impair adhesiveness, and the apparent melt viscosity of the added resin can be increased without melting by heat. Furthermore, it is possible to prevent the pressure portion from becoming thin during heat bonding (at the time of heat sealing), and to provide excellent sealing performance between the packaging material and the metal terminal.

  When pigment is added to the first and second polyolefin layers 12a and 12b, for example, when carbon black having a particle size of about 0.03 μm is used, the first and second polyolefin layers 12a and 12b are added. Is about 0.05 to 0.3 parts by mass, and preferably about 0.1 to 0.2 parts by mass, with respect to 100 parts by mass of the resin component that forms the resin. By adding pigments to the first and second polyolefin layers 12a and 12b, the presence or absence of the metal terminal adhesive film 1 can be detected by a sensor or visually inspected. In addition, when a filler and a pigment are added to the first and second polyolefin layers 12a and 12b, the filler and the pigment may be added to the same first and second polyolefin layers 12a and 12b. From the viewpoint of not hindering the heat-fusibility of the adhesive film 1 for use, it is preferable to add the filler and the pigment separately to the first and second polyolefin layers 12a and 12b.

  Each of the first and second polyolefin layers 12a and 12b can be made of a resin film. When the first and second polyolefin layers 12a and 12b are formed of a resin film, the resin film formed of the above-described polyolefin or acid-modified polyolefin is laminated on the base film 11 using, for example, a dry laminating method. Thereby, the adhesive film for metal terminals can be manufactured suitably. Moreover, the adhesive film for metal terminals can be suitably manufactured by extruding the resin which comprises the 1st and 2nd polyolefin layers 12a and 12b on the base film 11.

  When laminating the first and second polyolefin layers 12a and 12b made of a resin film on the surface of the base film 11, it is necessary on the surface of the first and second polyolefin layers 12a and 12b on the base film 11 side. Depending on the above, known easy-adhesion means such as corona discharge treatment, ozone treatment, and plasma treatment may be applied. In particular, due to the corona discharge treatment, the adhesion between the base film 11 and the first polyolefin layer 12a and the second polyolefin layer 12b is enhanced, and excellent sealing performance between the packaging material and the metal terminal can be imparted. .

  The thickness of the first and second polyolefin layers 12a, 12b can be appropriately selected according to the layer structure of the metal terminal adhesive film 1, considering the resin embedding after heat sealing, pinholes, In each case, the lower limit is preferably about 5 μm or more, more preferably about 20 μm or more, and the upper limit is preferably about 80 μm or less, more preferably about 50 μm or less. The thickness ranges of the first and second polyolefin layers 12a and 12b are preferably about 5 to 80 μm, about 5 to 50 μm, about 20 to 80 μm, and about 20 to 50 μm, respectively.

[Adhesion promoter layer]
The adhesion promoter layer (not shown) is a layer provided as necessary for the purpose of firmly bonding the base film 11 and the first and second polyolefin layers 12a and 12b. The adhesion promoter layer may be provided only on one side between the base film 11 and the first and second polyolefin layers 12a and 12b, or may be provided on both sides.

  The adhesion promoter layer can be formed using a known adhesion promoter such as isocyanate, polyethyleneimine, polyester, polyurethane, or polybutadiene. Among these, from the viewpoint of further improving the resistance to electrolytic solution, it is preferably formed of an isocyanate-based adhesion promoter. As the isocyanate-based adhesion promoter, those composed of an isocyanate component selected from a triisocyanate monomer and polymeric MDI are excellent in laminate strength and have a small decrease in laminate strength after being immersed in an electrolytic solution. In particular, triphenylmethane-4,4 ′, 4 ″ -triisocyanate which is a triisocyanate monomer and polymethylene polyphenyl polyisocyanate which is a polymeric MDI (NCO content is about 30%, viscosity is 200 to 700 mPa · s). It is particularly preferable to form a tri-isocyanate monomer such as tris (p-isocyanatephenyl) thiophosphate or a polyethyleneimine-based main component and polycarbodiimide as a cross-linking agent. It is also preferable to form with an adhesion promoter.

The adhesion promoter layer can be formed by coating and drying by a known coating method such as a bar coating method, a roll coating method, or a gravure coating method. The coating amount of the adhesion promoter, in the case of adhesion promoter consisting of triisocyanates, 20 to 100 mg / m ² about, preferably 40 to 60 mg / m ² about, in the case of adhesion promoter consisting of polymeric MDI , 40~150mg / m ² approximately, preferably is about 60 to 100 mg / m ^2, and a main agent of polyethylene imine, for two-component curing type adhesion promoter which is the polycarbodiimide crosslinking agent, 5 to 50 mg / M ² , preferably about 10 to 30 mg / m ² . The triisocyanate monomer is a monomer having three isocyanate groups in one molecule, and the polymeric MDI is a mixture of MDI and MDI oligomer obtained by polymerizing MDI, and is represented by the following formula.

  The metal terminal adhesive film 1 can be produced by laminating the first and second polyolefin layers 12 a and 12 b on both surfaces of the base film 11, respectively. Lamination | stacking with the base film 11 and the 1st and 2nd polyolefin layers 12a and 12b can be laminated | stacked by well-known methods, such as an extrusion lamination method and a thermal lamination method. Moreover, when laminating | stacking the base film 11 and the 1st and 2nd polyolefin layer 12a, 12b through an adhesion promoter layer, for example, the adhesion promoter which comprises an adhesion promoter layer is said method. What is necessary is just to apply | coat and dry on the base film 11, and to laminate | stack the 1st and 2nd polyolefin layers 12a and 12b from the adhesion promoter layer, respectively.

  The thickness (total thickness) of the metal terminal adhesive film 1 is not particularly limited, but the lower limit is preferably about 20 μm or more, more preferably about 50 μm or more, and the upper limit is preferably about 200 μm. Hereinafter, more preferably about 150 μm or less. In addition, the thickness range is preferably about 20 to 200 μm, about 20 to 150 μm, about 50 to 200 μm, and about 50 to 150 μm.

  The method for interposing the metal terminal adhesive film 1 between the metal terminal 2 and the packaging material 3 is not particularly limited. For example, the metal terminal 2 is sandwiched by the packaging material 3 as shown in FIGS. The metal terminal adhesive film 1 may be wound around the metal terminal 2 in the portion to be formed. Although not shown, the metal terminal adhesive film 1 is disposed on both sides of the metal terminal 2 so that the metal terminal adhesive film 1 crosses the two metal terminals 2 at the portion where the metal terminal 2 is sandwiched by the packaging material 3. May be.

  Moreover, the adhesive film 1 for metal terminals of the present invention is a packaging material that seals the battery elements and metal terminals that are electrically connected to the positive and negative electrodes of a battery element that includes at least a positive electrode, a negative electrode, and an electrolyte. It may be in the form of a wound body of an adhesive film for metal terminals interposed between the two. When it is a form of a winding body, the length of the winding direction of the adhesive film 1 for metal terminals is about 50-500 m, for example.

[Metal terminal 2]
The metal terminal 2 (tab) is a conductive member that is electrically connected to the electrode (positive electrode or negative electrode) of the battery element 4 and is made of a metal material. The metal material constituting the metal terminal 2 is not particularly limited, and examples thereof include aluminum, nickel, and copper. For example, the metal terminal 2 connected to the positive electrode of a lithium ion battery is usually made of aluminum or the like. Moreover, the metal terminal connected to the negative electrode of a lithium ion battery is normally comprised with copper, nickel, etc.

  The surface of the metal terminal 2 is preferably subjected to chemical conversion treatment from the viewpoint of improving the resistance to electrolytic solution. For example, when the metal terminal 2 is made of aluminum, specific examples of the chemical conversion treatment include known methods for forming an acid-resistant film such as phosphate, chromate, fluoride, and triazine thiol compound. . Among the methods for forming an acid-resistant film, a phosphoric acid chromate treatment using a phenol resin, a chromium (III) fluoride compound, and phosphoric acid is preferably used.

  What is necessary is just to set the magnitude | size of the metal terminal 2 suitably according to the magnitude | size etc. of the battery used. As thickness of the metal terminal 2, Preferably it is about 50-1000 micrometers, More preferably, about 70-800 micrometers is mentioned. Moreover, as length of the metal terminal 2, Preferably it is about 1-200 mm, More preferably, about 3-150 mm is mentioned. The width of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm.

[Packaging material 3]
Examples of the packaging material 3 include those having a laminated structure including at least a base material layer 31, a barrier layer 33, and a heat-fusible resin layer 35 in this order. In FIG. 5, as an example of a cross-sectional structure of the packaging material 3, a base material layer 31, an adhesive layer 32 provided as necessary, a barrier layer 33, an adhesive layer 34 provided as needed, and a heat-fusible resin A mode in which the layers 35 are stacked in this order will be described. In the packaging material 3, the base material layer 31 is the outermost layer, and the heat-fusible resin layer 35 is the innermost layer. When assembling the battery, the heat-fusible resin layers 35 positioned on the periphery of the battery element 4 are brought into contact with each other and heat-sealed, whereby the battery element 4 is sealed and the battery element 4 is sealed. 1 to 3 show a battery 10 in the case of using an embossed type packaging material 3 formed by embossing or the like, but the packaging material 3 is an unshaped pouch type. Also good. The pouch type includes a three-side seal, a four-side seal, and a pillow type, but any type may be used.

(Base material layer 31)
In the packaging material 3, the base material layer 31 is a layer that functions as a base material for the packaging material, and is a layer that forms the outermost layer side.

  The material for forming the base material layer 31 is not particularly limited as long as it has insulating properties. Examples of the material for forming the base material layer 31 include polyester, polyamide, epoxy, acrylic, fluorine resin, polyurethane, silicon resin, phenol, polyetherimide, polyimide, and mixtures and copolymers thereof. Polyesters such as polyethylene terephthalate and polybutylene terephthalate are excellent in electrolytic solution resistance and have the advantage that whitening or the like hardly occurs with respect to the adhesion of the electrolytic solution, and are preferably used as a material for forming the base layer 31. The polyamide film is excellent in stretchability, can prevent whitening due to resin cracking of the base material layer 31 during molding, and is suitably used as a material for forming the base material layer 31.

  The base material layer 31 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, particularly a biaxially stretched resin film has improved heat resistance due to orientation crystallization, and thus is preferably used as the base material layer 31.

  Among these, as a resin film which forms the base material layer 31, Preferably nylon and polyester, More preferably, biaxially stretched nylon and biaxially stretched polyester are mentioned.

  The base material layer 31 can be formed by laminating resin films of different materials in order to improve pinhole resistance and insulation when used as a battery package. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, and a multilayer structure in which a biaxially stretched polyester and a biaxially stretched nylon are laminated. When making the base material layer 31 into a multilayer structure, each resin film may be adhere | attached through an adhesive agent, and may be laminated | stacked directly without an adhesive agent. In the case of bonding without using an adhesive, for example, a method of bonding in a hot melt state such as a co-extrusion method, a sand lamination method, or a thermal laminating method can be mentioned.

  In addition, the base material layer 31 may be reduced in friction in order to improve moldability. When reducing the friction of the base material layer 31, the friction coefficient of the surface is not particularly limited, but for example, 1.0 or less can be mentioned. In order to reduce the friction of the base material layer 31, for example, mat treatment, formation of a thin film layer of a slip agent, a combination thereof, and the like can be given.

  About the thickness of the base material layer 31, about 10-50 micrometers is mentioned, for example, Preferably about 15-30 micrometers is mentioned.

(Adhesive layer 32)
In the packaging material 3, the adhesive layer 32 is a layer disposed on the base material layer 31 as necessary in order to impart adhesion to the base material layer 31. That is, the adhesive layer 32 is provided between the base material layer 31 and the barrier layer 33.

  The adhesive layer 32 is formed of an adhesive capable of bonding the base material layer 31 and the barrier layer 33. The adhesive used for forming the adhesive layer 32 may be a two-component curable adhesive or a one-component curable adhesive. Further, the adhesive mechanism of the adhesive used for forming the adhesive layer 32 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type, and the like.

  The resin component of the adhesive that can be used to form the adhesive layer 32 is excellent in spreadability, durability under high humidity conditions, a function of suppressing deformation, a function of suppressing thermal degradation during heat sealing, and the like. From the viewpoint of effectively suppressing the occurrence of delamination by suppressing a decrease in the strength of the laminate between the layers 33, a polyurethane two-component curable adhesive; preferably a polyamide, a polyester, or a blend of these with a modified polyolefin Resin.

  Further, the adhesive layer 32 may be multilayered with different adhesive components. When the adhesive layer 32 is multilayered with different adhesive components, from the viewpoint of improving the laminate strength between the base material layer 31 and the barrier layer 33, the adhesive component disposed on the base material layer 31 side is used as the base material layer. It is preferable to select a resin having excellent adhesiveness with 31 and select an adhesive component having excellent adhesiveness with the barrier layer 33 as the adhesive component disposed on the barrier layer 33 side. When the adhesive layer 32 is multilayered with different adhesive components, specifically, the adhesive component disposed on the barrier layer 33 side is preferably acid-modified polyolefin, metal-modified polyolefin, polyester and acid-modified polyolefin. And mixed resins, resins containing copolymerized polyesters, and the like.

  About the thickness of the adhesive bond layer 32, about 2-50 micrometers is mentioned, for example, Preferably about 3-25 micrometers is mentioned.

(Barrier layer 33)
In the packaging material, the barrier layer 3 is a layer having a function of preventing the entry of water vapor, oxygen, light and the like into the battery in addition to improving the strength of the packaging material. Specific examples of the metal constituting the barrier layer 3 include aluminum, stainless steel, and titanium, and preferably aluminum. The barrier layer 3 can be formed by, for example, a metal foil, a metal vapor-deposited film, an inorganic oxide vapor-deposited film, a carbon-containing inorganic oxide vapor-deposited film, a film provided with these vapor-deposited films, etc. It is more preferable that it is formed of an aluminum foil. From the viewpoint of preventing the generation of wrinkles and pinholes in the barrier layer 3 during the production of the packaging material, the barrier layer is made of, for example, annealed aluminum (JIS H4160: 1994 A8021H-O, JIS H4160: 1994 A8079H). -O, JIS H4000: 2014 A8021P-O, JIS H4000: 2014 A8079P-O) and the like are more preferable.

  The thickness of the barrier layer 33 is preferably about 10 to 200 μm, more preferably about 20 to 100 μm, from the viewpoint of reducing the thickness of the packaging material and preventing pinholes from being formed even by molding.

  The barrier layer 3 is preferably subjected to chemical conversion treatment on at least one surface, preferably both surfaces, for stabilization of adhesion, prevention of dissolution and corrosion, and the like. Here, the chemical conversion treatment refers to a treatment for forming an acid-resistant film on the surface of the barrier layer.

[Adhesive layer 34]
In the packaging material 3, the adhesive layer 34 is a layer provided as necessary between the barrier layer 33 and the heat-fusible resin layer 35 in order to firmly bond the heat-fusible resin layer 35.

  The adhesive layer 34 is formed of an adhesive that can adhere the barrier layer 33 and the heat-fusible resin layer 35. Although it does not restrict | limit especially about the composition of the adhesive agent used for formation of an contact bonding layer, For example, the resin composition containing acid-modified polyolefin is mentioned. Examples of the acid-modified polyolefin include the same ones as exemplified in the first and second polyolefin layers 12a and 12b.

  About the thickness of the contact bonding layer 34, about 1-40 micrometers is mentioned, for example, Preferably about 2-30 micrometers is mentioned.

[Heat-fusion resin layer 35]
In the packaging material 3, the heat-fusible resin layer 35 corresponds to the innermost layer, and is a layer that heat-fuses the heat-fusible resin layers and seals the battery element when the battery is assembled.

  The resin component used for the heat-fusible resin layer 35 is not particularly limited as long as it can be heat-sealed, and examples thereof include polyolefin and cyclic polyolefin.

  Specific examples of the polyolefin include polyethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; homopolypropylene, polypropylene block copolymer (for example, block copolymer of propylene and ethylene), polypropylene And crystalline or amorphous polypropylene such as a random copolymer of propylene and ethylene (eg, a terpolymer of ethylene-butene-propylene). Among these polyolefins, polyethylene and polypropylene are preferable.

  The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. It is done. Examples of the cyclic monomer that is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, a cyclic alkene is preferable, and norbornene is more preferable. Examples of the constituent monomer include styrene.

  Among these resin components, preferably a crystalline or amorphous polyolefin, a cyclic polyolefin, and a blend polymer thereof; more preferably, polyethylene, polypropylene, a copolymer of ethylene and norbornene, and two or more of these The blend polymer of these is mentioned.

  The heat-fusible resin layer 35 may be formed of one kind of resin component alone or may be formed of a blend polymer in which two or more kinds of resin components are combined. Furthermore, although the heat-fusible resin layer 35 may be formed of only one layer, it may be formed of two or more layers using the same or different resin components.

  In addition, the thickness of the heat-fusible resin layer 35 is not particularly limited, but may be about 2 to 2000 μm, preferably about 5 to 1000 μm, and more preferably about 10 to 500 μm.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

<Measurement of the maximum in-plane orientation direction (Y _max direction) of the naphthalene ring>
The Y _max direction which is the maximum in-plane orientation direction of the naphthalene ring contained in each substrate film (polyethylene naphthalate (PEN) film) used in the following Examples and Comparative Examples was measured by the following method. First, by the polarization measurement of the single reflection ATR method of Fourier transform infrared spectroscopy, the surface of the base film is infrared in 18 directions in increments of 10 ° from 0 ° to 170 ° in a direction perpendicular to the thickness direction. Absorption spectra were acquired. Here, the said surface of a base film is a surface which laminates | stacks an acid-modified polyolefin layer. Next, in each of the 18 directions, the value Y was calculated by dividing the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ . Next, the direction in which the maximum value Y _max among the obtained values Y (18 values) was obtained was defined as the Y _max direction. The results are shown in Table 1. Specific measurement conditions of the infrared absorption spectrum are as follows.

(Infrared absorption spectrum measurement conditions)
Spectrometer: IS10 manufactured by Thermo
Attached device: One-time reflection ATR accessory device (Seagull)
Detector: MCT (Hg Cd Te)
Resolution: 8cm ^-1
IRE: Ge
Incident angle: 30 °
Polarizer: wire-grid, S-polarized light Baseline: 1800 cm ^-1 mean absorption peak intensity of the intensity at 2000 cm ^-1 from Y _765: baseline values from the maximum value of the peak intensity from 760 cm ^-1 in the range of 770 cm ^-1 Subtracted value Absorption peak intensity Y ₁₁₈₁ : A value obtained by subtracting the baseline value from the maximum peak intensity in the range of 1176 cm ⁻¹ to 1186 cm ^−1.

Example 1-3 and Comparative Example 1-2
<Preparation of adhesive film for metal terminals>
A sequential biaxially stretched PEN film (thickness: 12 μm) subjected to double-sided corona discharge treatment was used as the base film. One side of the PEN film was coated with 50 mg / m ^{2 of} an adhesion promoter of triphenylmethane-4,4 ′, 4 ″ -triisocyanate as a solid content by a gravure printing method, dried, and then a T-die extruder. Then, maleic acid-modified polypropylene (hereinafter referred to as PPa) to which 0.15 parts by weight of carbon black was added was extruded and applied in a thickness of 30 μm, and then the other surface of the PEN film was bonded in the same manner. Accelerating agent and PPa were applied, followed by aging treatment at 45 ° C. for 72 hours, and an adhesive film for metal terminals of PPa layer / adhesion promoter layer / PEN film / adhesion promoter layer / PPa layer (total thickness 72 μm) )

<Production of packaging materials>
One side of a barrier layer composed of an aluminum foil (thickness 40 μm) that has been subjected to chemical conversion treatment (phosphate chromate treatment) on both sides with a chemical conversion treatment solution containing three components of phenol resin, chromium fluoride (trivalent) compound and phosphoric acid in advance. And a base material layer made of a biaxially stretched nylon film (thickness: 25 μm) was laminated by a dry laminating method. Specifically, a polyester adhesive is applied to one surface of the barrier layer by a gravure printing method, dried (dry mass: 4.0 g / m ² ), the base material layer is bonded, and then an aging treatment is performed. gave. Next, an adhesive layer (thickness 22.5 μm) made of maleic anhydride-modified polypropylene and a heat-fusible resin layer (thickness 22.5 μm) made of random polypropylene are coextruded on the other surface of the barrier layer. By heating, a battery packaging material having the order of base material layer / adhesive layer / metal foil / adhesive layer / heat-fusible resin layer was obtained.

<Production of test battery>
The obtained packaging material was cut into 160 mm (MD: Machine Direction, vertical direction) × 90 mm (TD: Transverse Direction direction, horizontal direction). This is a rectangular molding die having a caliber of 50 mm (MD) × 30 mm (TD) (female mold, surface is JIS B 0659-1: 2002 Annex 1 (reference) Table of surface roughness standard pieces for comparison 2 and the maximum height roughness (nominal value of Rz) is 3.2 μm) and a corresponding molding die (male mold, surface is JIS B 0659-1: 2002 Annex 1 ( Reference) Using the maximum height roughness (nominal value of Rz) defined in Table 2 of the comparative surface roughness standard piece is 1.6 μm, and molding with a pressing surface pressure of 0.4 MPa and 3.0 mm. Cold-formed to the depth (one-step drawing). At this time, the heat-sealable resin layer side was placed on the male mold side, and the clearance between the male mold and the female mold was set to 0.5 mm. The formed molding cup position M is as shown in FIG. Next, the packaging material after molding is folded in half at the position of the crease (middle P of MD) so that the heat-sealable resin layer surfaces overlap each other, and a dummy cell (PET plate, 45 mm × 28 mm × thickness 3 mm) 2 so that the adhesive film for metal terminal and the dummy metal terminal (aluminum foil having a thickness of 0.1 mm, a width of 5 mm, and a length of 30 mm) are in the positional relationship shown in FIG. With this arrangement, two sides were heat-sealed along the forming cup in the order of the short side and the long side. Here, the two dummy metal terminals were arranged so as to be taken out from the short side, and the heat seal conditions were 190 ° C., 3 seconds, and pressure 1.4 MPa using a 7 mm width head. One surface of the adhesive film for metal terminal is heat-sealed with the dummy metal terminal, and the other surface is heat-sealed with the heat-fusible resin layer. After two-side heat sealing, it is dried in a dry room for 24 hours, and 0.5 g of water is sealed as a virtual electrolyte from the other side that is not heat-sealed in the dry room, and has an internal space (pressure 1 atm). Made a case. Next, the peripheral portion was cut so that the width of the portion where the heat-fusible resin layers were heat-sealed was 3 mm, and thus a test battery 13 was obtained.

<Opening test of packaging material>
As shown in FIG. 8A, the test battery 13 obtained above is placed in a space between two stainless steel plates so that the interval W between the two stainless steel plates is 7.0 mm. The fixing spacer 20 was adjusted. Next, in this state, the pressure is set in an oven that can be decompressed (vacuum drying oven AVO-310NS-D manufactured by AS ONE) so that the pressure in the oven becomes 5000 Pa, and a temperature increase rate of 35 ° C./min. The temperature was raised to 120 ° C. (as shown in FIG. 8B, the test battery 13 expanded), and the presence or absence of opening at the portion where the metal terminal adhesive film was located was confirmed. . The results are shown in Table 1.

  In the batteries of Comparative Examples 1 and 2, when the location where the packaging material was opened was visually observed, it was confirmed that cohesive failure occurred at the position of the base film of the adhesive film for metal terminals.

<Measurement of laminate strength between PEN film and PPa layer of adhesive film for metal terminal>
The adhesive film for metal terminals obtained above was cut into a size of 100 mm (longitudinal direction) × 15 mm (lateral direction) to obtain a sample. At this time, as the samples of Examples 1 to 3 and Comparative Examples 1 and 2, the angles formed by the vertical direction of the samples and the Y _max direction of the adhesive film for metal terminals are respectively the angles θ in Table 1. A sample was obtained by cutting the adhesive film for metal terminals so as to match the above. Next, in a room temperature environment (25 ° C.), the PEN film and the PPa layer of the metal terminal adhesive film are each chucked (distance between chucks 50 mm), and a tensile tester (AGS-1kNX manufactured by Shimadzu Corporation) is used. Then, it was pulled in the direction of 180 ° (longitudinal direction) at a speed of 50 mm / min, and the laminate strength (N / 15 m) between the PEN film and the PPa layer of the adhesive film for metal terminals was measured. The results are shown in Table 1. The laminate strength (N / 15 m) is an average value of 20 samples.

DESCRIPTION OF SYMBOLS 1 Adhesive film for metal terminals 2 Metal terminal 3 Packaging material 3a Peripheral part of packaging material 4 Battery element 5 Metal terminal with adhesive film for metal terminals 10 Battery 11 Base film 12a First polyolefin layer 12b Second polyolefin layer 13 Test Battery 13a Edge 20 Fixing spacer 21 Stainless steel plate 31 Base material layer 32 Adhesive layer 33 Barrier layer 34 Adhesive layer 35 Heat-fusible resin layer

Claims (9)

A battery element including at least a positive electrode, a negative electrode, and an electrolyte; a packaging material that seals the battery element; and a metal terminal that is electrically connected to each of the positive electrode and the negative electrode and extends outside the packaging material. A battery comprising:
Between the metal terminal and the packaging material, an adhesive film for metal terminal is disposed,
The metal terminal adhesive film includes a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
A battery in which an angle θ between a Y _max direction and a direction in which the metal terminal extends to the outside of the packaging material, measured by the following method, is 45 ° or more and 135 ° or less.
The measurement method in the Y _max direction is a step of 10 ° from 0 ° to 170 ° in the direction perpendicular to the thickness direction on the surface of the base film by polarization measurement using a single reflection ATR method of Fourier transform infrared spectroscopy. When the infrared absorption spectrum in 18 directions is acquired, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum is divided by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ in each of the 18 directions. The value Y is calculated, and the direction in which the maximum value Y _max among the values Y is obtained is defined as the Y _max direction.   The battery according to claim 1, wherein a thickness of the base film of the adhesive film for metal terminals is 10 μm or more and 50 μm or less.   The battery according to claim 1 or 2, wherein the first polyolefin layer and the second polyolefin layer of the adhesive film for metal terminals include an acid-modified polyolefin.   The battery in any one of Claims 1-3 whose thickness of the said 1st polyolefin layer of the said adhesive film for metal terminals and the said 2nd polyolefin layer is 5 micrometers or more and 80 micrometers or less, respectively.   The battery in any one of Claims 1-4 whose thickness of the said adhesive film for metal terminals is 20 micrometers or more and 200 micrometers or less.   The battery according to any one of claims 1 to 5, wherein the packaging material is composed of a laminate including at least a base material layer, a barrier layer, and a heat-fusible resin layer in this order. A battery element including at least a positive electrode, a negative electrode, and an electrolyte, a packaging material that seals the battery element, and a metal terminal that is electrically connected to each of the positive electrode and the negative electrode and protrudes outside the packaging material A method of manufacturing a battery comprising:
A step of arranging an adhesive film for metal terminals between the metal terminal and the packaging material;
As the adhesive film for metal terminals, a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer are provided in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
A method for producing a battery, wherein an angle θ between a Y _max direction and a direction in which the metal terminal extends to the outside of the packaging material, measured by the following method, is 45 ° or more and 135 ° or less.
The measurement method in the Y _max direction is a step of 10 ° from 0 ° to 170 ° in the direction perpendicular to the thickness direction on the surface of the base film by polarization measurement using a single reflection ATR method of Fourier transform infrared spectroscopy. When the infrared absorption spectrum in 18 directions is acquired, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum is divided by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ in each of the 18 directions. The value Y is calculated, and the direction in which the maximum value Y _max among the values Y is obtained is defined as the Y _max direction. It is a metal terminal with an adhesive film for metal terminals in which an adhesive film for metal terminals is attached to a metal terminal of a battery,
The metal terminal adhesive film includes a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
When the metal terminal is attached to the battery, the angle θ formed by the direction extending outside the battery and the Y _max direction of the metal terminal adhesive film measured by the following method is 45 ° or more and 135 °. The metal terminal with an adhesive film for a metal terminal, wherein the metal terminal adhesive film is attached to the metal terminal so as to be as follows.
The measurement method in the Y _max direction is a step of 10 ° from 0 ° to 170 ° in the direction perpendicular to the thickness direction on the surface of the base film by polarization measurement using a single reflection ATR method of Fourier transform infrared spectroscopy. When the infrared absorption spectrum in 18 directions is acquired, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum is divided by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ in each of the 18 directions. The value Y is calculated, and the direction in which the maximum value Y _max among the values Y is obtained is defined as the Y _max direction. At least a positive electrode, a negative electrode, and an adhesive film for a metal terminal interposed between a metal terminal electrically connected to the positive electrode and the negative electrode of a battery element having an electrolyte and a packaging material for sealing the battery element A winding body of
The metal terminal adhesive film includes a first polyolefin layer, a base film containing polyethylene naphthalate, and a second polyolefin layer in this order,
At least one of the first polyolefin layer and the second polyolefin layer contains an acid-modified polyolefin,
Adhesion for metal terminals, in which an angle θ between the Y _max direction and the direction orthogonal to the winding direction of the winding body of the adhesive film for metal terminals, measured by the following method, is 45 ° or more and 135 ° or less. Of rolled film.
The measurement method in the Y _max direction is a step of 10 ° from 0 ° to 170 ° in the direction perpendicular to the thickness direction on the surface of the base film by polarization measurement using a single reflection ATR method of Fourier transform infrared spectroscopy. When the infrared absorption spectrum in 18 directions is acquired, the absorption peak intensity Y ₇₆₅ at ₇₆₅ cm ⁻¹ of the infrared absorption spectrum is divided by the absorption peak intensity Y ₁₁₈₁ at ₁₁₈₁ cm ⁻¹ in each of the 18 directions. The value Y is calculated, and the direction in which the maximum value Y _max among the values Y is obtained is defined as the Y _max direction.