JP2008016337A - Lead wire covering film material for battery, and film-covered lead wire for battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain the airtightness of a container and prevent short circuit between a lead wire and a metal layer in a container half body. <P>SOLUTION: Film-covered lead wires for a battery (2) and (3) are connected to a positive electrode and a negative electrode inside a power generation element sealed container (1), and have ends extracted out of the container (1). The container (1) is formed in such a way that a pair of molded container half bodies (7) and (8) each composed of a thermoplastic synthetic resin layer (4), a metal layer (5), and a thermoplastic synthetic resin layer (6) are so disposed that the thermoplastic synthetic resin layers (6) face each other as innermost layers; and that peripheral edges (9) and (10) of the container half bodies (7) and (8) are heat welded together. The lead wires (2) and (3) are held between a pair of films (11) and (12), thus being covered with the films (11) and (12) at a mating face between the peripheral edges (9) and (10) of the container half bodies (7) and (8). Each of the covering films (11) and (12) is composed of three thermoplastic synthetic resin layers consisting of an outer layer (13), an intermediate layer (14), and an inner layer (15), among which the intermediate layer (14) is dispersed with insulating fine grains (16). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery lead wire covering film material and a battery film covering lead wire.

  In this specification, the power generation element refers to a positive electrode, a negative electrode, a diaphragm, an electrolytic solution, and the like housed in a sealed container. Further, the sealed container includes a bag formed by joining the peripheral portions of a pair of films outside a container formed by joining a pair of flanged tray-shaped molded container halves.

Conventional batteries, particularly thin polymer battery leads, are connected to the positive and negative electrodes inside the power generation element sealed container, respectively, and the ends are taken out of the container. The container is made of a metal layer and a thermoplastic synthetic resin layer. A pair of container halves including the inner side of the thermoplastic synthetic resin layer are heat-sealed at the periphery thereof, and the middle of the length of the lead wire is interposed at the joint of the periphery of both container halves Has been.
The portion corresponding to the seam of the lead wire is sandwiched between two thermoplastic resin films, which are heat-sealed and coated on the lead wire. With this coating film, the lead wire is placed on the periphery of both container halves. It is heat-sealed at the joint.

  In recent years, the polymer battery has been required to increase its output due to the expansion of applications, and the size of the battery tends to increase, and accordingly, the strip-shaped lead wire used for the battery has also increased in size. Therefore, when the conventional coated film is heat-sealed to the lead wire, a high heat-sealing condition is required. As a result, the amount of the thermoplastic resin flowing out becomes large and the lead wire edge is exposed, leading to the lead wire. A short circuit may occur due to insufficient insulation between the wire and the metal layers in the container half.

  Therefore, in order to prevent this short circuit, an insulating layer that does not melt at the time of thermal fusion is interposed between the metal layer in the container half and the thermoplastic synthetic resin layer as disclosed in Patent Document 1 below. What is being known. However, this has the disadvantage that the number of steps for providing an extra insulating layer during the production of the container half increases and the cost is increased.

In order to eliminate this disadvantage, as disclosed in Patent Document 2 below, the metal layer and the metal layer in the container half are prevented from being short-circuited without providing an insulating layer. It has been proposed that insulating particles are interspersed in a thermoplastic synthetic resin layer of a pair of container halves including a thermoplastic synthetic resin layer.
JP-A-9-283100 JP 2000-173558 A

  Indeed, according to the proposal disclosed in Patent Document 2, when a pair of container halves are placed inside the insulating synthetic resin-containing thermoplastic synthetic resin layers, and are thermally fused at the peripheral edge of the lead connection, the lead wire and the container half Insulating particles are interposed between the metal layer of the body and there is no possibility of short circuit between the lead wire and the metal layer. However, in the thermoplastic synthetic resin layer containing insulating particles, heat fusion with the lead wire is not sufficient, the hermeticity of the power generation element sealed container is lowered, and the battery performance is reduced due to leakage of electrolyte and penetration of moisture. There is a fear.

  The objective of this invention is providing the lead wire for batteries which does not have a possibility that a lead wire and the metal layer in a container half may short-circuit, without reducing the airtightness of a power generation element sealed container.

  The lead wire covering film material for a battery according to the invention of claim 1 is such that the power generation element sealed container of the battery has a pair of container halves including a metal layer and a thermoplastic synthetic resin layer inside the thermoplastic synthetic resin layers, and its peripheral edge At least the seam corresponding to the lead wire connected to the positive electrode and the negative electrode inside the container and having the end part taken out from the joint of the peripheral part of both container halves to the outside of the container. A film material that is locally heat-sealed and coated on the peripheral part of both container halves, the film material comprising at least three thermoplastic synthetic resin layers, of which the entire intermediate layer Insulating fine particles are interspersed and contained.

Specific examples of at least three layers of thermoplastic synthetic resin constituting the film material include heat fusion of polyethylene, low density polyethylene, high density polyethylene, acid-modified polyethylene, block polypropylene, random polypropylene, acid-modified polypropylene, ionomer, and the like. It is preferable that it is resin excellent in property.
The at least three layers may be the same thermoplastic synthetic resin or different thermoplastic synthetic resins.

  The lead wire is usually made of the same material as the electrode, but may be made of a different material. Generally, aluminum is used for the positive electrode material, and nickel or copper is used for the negative electrode material. Therefore, aluminum is used for the lead wire connected to the positive electrode, and nickel or copper is used for the lead wire connected to the negative electrode. The

  Specific examples of the material for the insulating fine particles include silicon oxide, magnesium oxide, aluminum oxide, calcium carbonate, polyethylene terephthalate, polyamide, phenol resin, and epoxy resin. The particle diameter of these insulating fine particles is preferably 5 to 100 μm. If the particle size is less than 5 μm, the lead wire and the metal layer in the container half may be short-circuited. If the particle size exceeds 100 μm, the thickness of the insulating synthetic fine particle-containing thermoplastic synthetic resin layer is unnecessarily increased. There must be.

  The invention according to claim 2 is the battery lead wire covering film material according to claim 1, wherein the content ratio of the insulating fine particles to the thermoplastic synthetic resin of the intermediate layer is 1 to 30% by weight. It is.

  In the above, the content ratio of the insulating fine particles to the thermoplastic synthetic resin in the intermediate layer is limited to 1 to 30% by weight. If the content is less than 1% by weight, the lead wire and the metal layer in the container half may be short-circuited. On the contrary, if it exceeds 30% by weight, the strength of the insulating synthetic fine particle-containing thermoplastic synthetic resin layer becomes weak, and there is a possibility that the lead wire and the metal layer in the container half are short-circuited. Especially preferably, it is 5 to 15 weight% in 1 to 30 weight%.

  The battery film-coated lead wire according to the invention of claim 3 is a pair of opposed films obtained from the battery lead wire-covered film material of claim 1 or 2 and is a half of the length of one lead wire. A predetermined portion including a portion corresponding to the joint of the peripheral edge of the body is sandwiched, both films are heat-sealed to the lead wire, and the edges of both films protruding on both sides of the lead wire are heat-sealed. The lead wire is locally covered with a film.

  The battery film-coated lead wire according to the invention of claim 4 is a length of two lead wires spaced apart from each other by a pair of inward films obtained from the battery lead wire-coated film material of claim 1 or 2. Both films are sandwiched between predetermined portions including portions corresponding to the joints of the peripheral edges of both container halves, and both films are thermally fused to the lead wires, and project between the two lead wires and on both sides The two edges are locally covered with a film by heat-sealing the edges of each other.

  The battery-coated lead wire for battery according to the invention of claim 5 is a half-fold film obtained from the battery lead wire-covering film material according to claim 1 or 2 and is a match between the peripheral edges of both container halves in the length of the lead wire. A predetermined portion including the portion corresponding to the eyes is sandwiched, and both halves of the half-fold film are heat-sealed to the lead wire, and the edges protruding to one side of the lead wire are heat-sealed to form the lead wire. It is characterized by being locally covered with a film.

The battery-coated lead wire for a battery according to the invention of claim 6 is a length of two lead wires separated from each other by a bi-fold film obtained from the battery lead wire-coated film material according to claim 1 or 2. A predetermined portion including a portion corresponding to the joint between the peripheral portions of both container halves is held, and both halves of the two-fold film are heat-sealed to the lead wire, and between the two lead wires and one of the lead wires. The edges projecting to one side are heat-sealed and the two lead wires are locally covered with a film.

  According to the battery film-coated lead wire according to any one of claims 3 to 6 using the battery lead wire-coated film material according to the invention of claim 1 or 2, the airtightness of the power generation element sealed container is lowered. In addition, there is no possibility that the lead wire and the metal layer in the container half are short-circuited.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  As shown in FIGS. 2 and 3, the power generation element sealed container (1) of the thin polymer battery shown in FIG. 1 is composed of a thermoplastic synthetic resin layer (4) that serves as a surface protective layer and an aluminum foil that serves as a barrier layer. The inner surface thermoplastic synthetic resin layers (6) of the pair of flanged tray-shaped molded container halves (7) and (8) comprising the layer (5) and the thermoplastic synthetic resin layer (6) to be the fusion layer are placed inside. The film-coated lead wires (2) and (3) for the battery are coated with a positive electrode and a negative electrode (shown in the figure). And ends of the container halves (7) and (8) are taken out from the joints of the peripheral edges of the container (1). As shown in FIG. 5, each lead wire (2) (3) includes a pair of films (including a width of the peripheral portion (9) (10)) that protrudes to the outside and covers both sides thereof. 11) It is encased in (12) and locally heat-sealed. The films (11) and (12) are made of a three-layered plastic synthetic resin comprising an outer layer (13), an intermediate layer (14), and an inner layer (15), of which insulating fine particles (16) are scattered in the intermediate layer (14). It is obtained by cutting into the above size from the battery lead wire covering film material (F) of FIG. 4 contained.

In the above embodiment, a pair of films (11) and (12) are used to cover each lead wire (2) and (3). However, as shown in FIG. 6, the battery lead wire coating shown in FIG. The lead wires (2) and (3) may be sandwiched between two folded films (17) obtained by cutting from the film material (F), and may be locally heat-sealed.
Furthermore, as shown by the chain line in FIG. 1, the two lead wires (2) and (3) spaced by a pair of opposed films obtained from the battery lead edge covering film material (F) are sandwiched, Both films are heat-sealed to the two lead wires (2) and (3), and the edges of both films protruding between the two lead wires (2) and (3) and both sides are fused. The two lead wires (2) and (3) may be locally covered with a film. Also in the case of a two-fold film, the two lead wires (2) and (3) can be locally covered together with the film.

  The battery lead wire covering film material (F), which is the material of the pair of films (11) and (12), has a thickness of 150 μm, the outer layer (13) has a thickness of 25 μm, and is a random polypropylene as a thermoplastic synthetic resin. The thickness of the intermediate layer (14) is 100 μm, block polypropylene is used as the thermoplastic synthetic resin, and magnesium oxide having an average particle size of 30 μm as the insulating fine particles (16) is compared to the block polypropylene. The inner layer (15) has a thickness of 25 μm, and acid-modified polypropylene is used as a thermoplastic synthetic resin.

  An aluminum ribbon having a thickness of 200 μm and a width of 10 mm is used as the lead wire (2) connected to the positive electrode, and a nickel ribbon having the same dimensions is used as the lead wire (3) connected to the negative electrode. It was.

  Each lead wire (2) (3) is interposed between a pair of films (11) and (12) each having the above-mentioned size, and heated locally at 250 ° C. for 10 seconds under a pressure of 0.2 Mpa. The film was coated by fusion bonding to form a film-coated lead wire for a battery.

  Low density polyethylene is used as the thermoplastic synthetic resin of the outer layer (13), high density polyethylene is used as the thermoplastic synthetic resin of the intermediate layer (14), and acid-modified polyethylene is used as the thermoplastic synthetic resin of the inner layer (15). Example 1 is the same as Example 1.

Comparative Example 1

  Example 2 is the same as Example 2 except that the insulating fine particles are not combined with the thermoplastic synthetic resin of the intermediate layer.

Comparative Example 2

  Example 1 is the same as Example 1 except that an ionomer consisting of only one layer is used as the pair of films.

Ten sets of two lead wires connected to the positive electrode and the negative electrode coated with the film of each of the above examples are prepared as evaluation samples, and each lead wire is a thermoplastic synthetic resin layer and a barrier layer serving as a surface protective layer in order from the outside. Sandwiched between the peripheral edges of a pair of flanged tray-shaped molded container halves constituting a container composed of a metal layer to become a thermoplastic synthetic resin layer to be a fusion layer, and heated at 250 ° C. for 10 seconds, 0. Crimped at 2 MPa.
A series resistance value measured with a Sanwa Electric Multi-Tester JR-8D is measured for the series resistance value between the metal layer end face serving as the barrier layer of the container half and the covering film in which the lead wire is interposed. The coating film insulation was normal and no short circuit occurred, and samples exceeding this value were evaluated as insufficient insulation and short circuit occurred. The results are shown in Table 1. Table 1 shows the number of sample sets as a denominator and the number of short-circuited sample sets as a numerator.

  As shown in Table 1, in Example 1 and Example 2, no short circuit was observed, but in Comparative Example 1 and Comparative Example 2, a short circuit was observed with a high probability.

It is a top view which shows the film covering lead wire which was connected to the positive electrode and the negative electrode inside a power generation element sealing container of a battery, respectively, and the edge part was taken out outside the container. FIG. 2 is a partially enlarged side view in which a part of FIG. 1 is cut away. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a partial vertical sectional view of a lead wire covering film material for a battery. It is a fragmentary perspective view of the film-coated lead wire for a battery locally covered with a pair of opposed films. It is a fragmentary perspective view of the film-coated lead wire for batteries locally covered with the double fold film.

Explanation of symbols

(1) Battery power generation element sealed container (2) (3) Film-coated lead wire for battery (4) Thermoplastic synthetic resin layer to be a surface protective layer (5) Metal layer to be a barrier layer (6) Fusion layer and Mature plastic synthetic resin layer (7) (8) Container half (9) (10) Perimeter of container half (11) (12) Film (13) Film outer layer (14) Film intermediate layer (15) Inner layer of film (16) Insulating fine particles (17) Folded film (F) Lead wire covering film material for battery

Claims (6)

  A battery power generation element sealed container is formed by placing a pair of container halves including a metal layer and a thermoplastic synthetic resin layer inside the thermoplastic synthetic resin layers and heat-sealing at the peripheral edge thereof. Are connected to the positive electrode and the negative electrode of the container, and at least a portion corresponding to the joint of the lead wire from which the end of the container half is taken out to the outside of the container is locally heat-sealed. A film material for heat-sealing to a peripheral part of a body, characterized in that the film material is composed of at least three thermoplastic synthetic resin layers, and among them, insulating fine particles are scattered and contained in the entire intermediate layer. A lead wire covering film material for a battery.   The lead wire-covered film material for a battery according to claim 1, wherein the content ratio of the insulating fine particles to the thermoplastic synthetic resin in the intermediate layer is 1 to 30% by weight.   A predetermined portion of the length of one lead wire is sandwiched between a pair of opposed films obtained from the lead wire covering film material for a battery according to claim 1 or 2, and both films are thermally fused to the lead wire. A film-coated lead wire for a battery, characterized in that the edges of both films protruding on both sides of the lead wire are heat-sealed and the lead wire is locally covered with the film.   3. Corresponding to the joint between the peripheral edges of both container halves out of the length of two lead wires spaced apart by a pair of opposing films obtained from the battery lead wire covering film material according to claim 1 or 2. A predetermined portion including a portion is sandwiched, and both films are heat-sealed to the lead wire, and the edges of both films protruding between the two lead wires and both sides are heat-sealed to form two leads. A film-coated lead wire for a battery, wherein the wire is locally covered with a film.   A predetermined portion including a portion corresponding to the joint between the peripheral portions of both container halves of the length of one lead wire is sandwiched between the two-fold films obtained from the lead wire covering film material for a battery according to claim 1 or 2. The two halves of the folded film are fused to the lead wire, and the edges of the two folded film halves protruding to one side of the lead wire are thermally fused together, so that the lead wire is localized by the film. A film-coated lead wire for a battery, which is coated. A portion corresponding to the joint of the peripheral edges of both container halves of the length of two lead wires separated from each other by a two-fold film obtained from the battery lead wire covering film material according to claim 1 or 2. The two halves of the two-fold film are sandwiched between the two lead wires and one side of one lead wire, and the edges of both halves of the two-fold film are sandwiched between the two fold films. A film-coated lead wire for a battery, characterized in that the parts are heat-sealed and the two lead wires are locally covered with a film.

Images