JP2022061268A - Tab lead and non-aqueous electrolyte device - Google Patents

Abstract

To provide a tab lead which attains prolongation of lifetime of a non-aqueous electrolyte device by reducing deterioration caused by intrusion of moisture.SOLUTION: The present invention relates to a tab lead 1 comprising: a lead terminal 2 formed from a metal material; and a pair of film parts 3 being adhered from both sides to the lead terminal and sealing a gap between the lead terminal and a laminate material 101. The film part is configured in three layers of a first resin film 7, a second resin film 8 and a third resin film 9 in a thickness direction. The first resin film is adhered to the lead terminal by thermal compression bonding, and the third resin film is adhered to the laminate material by thermal compression bonding. The second resin film includes dispersed desiccant agents 6 inside, and heat resistance thereof is set higher than that of the first resin film and the third resin film. A cover part 10 covering an end face of the second resin film at a side of an electrode connection part 2a and an end face at a side of an external terminal part 2b is provided on at least one of the first resin film and the third resin film.SELECTED DRAWING: Figure 2

Description

The present invention relates to a technical field of a tab lead in which a film portion is closely attached to a lead terminal and a non-aqueous electrolyte device provided with the tab lead.

Non-aqueous electrolyte devices such as lithium-ion batteries used as in-vehicle batteries and storage batteries include laminated non-aqueous electrolyte devices in which an electrode and an electrolyte or a solid electrolyte are enclosed inside a bag-shaped laminate material. There is. In a laminated non-aqueous electrolyte device, power is taken out by a tab lead having one end connected to an electrode and the other end exposed to the outside of the laminated material.

Such a tab lead includes a metal lead terminal that functions as a terminal member for extracting electric power, and a film portion that seals a gap between the lead terminal and the laminated material and insulates the two. It is provided. By thermocompression bonding the film portion, the gap between the lead terminal and the laminated material is sealed.

The tab lead contains particles (non-meltable resin) that exhibit non-meltability at the temperature at the time of thermocompression bonding dispersed inside the film portion (see, for example, Patent Document 1), or the film portion. It is known that particles having a particle size smaller than the thickness of the resin film are dispersed and contained inside the resin film (see, for example, Patent Document 2). In the tab leads shown in Patent Document 1 and Patent Document 2, the particles dispersed inside the film portion prevent the laminate material from coming into contact with the lead terminal during thermocompression bonding of the film portion, and the insulation between the two is ensured. Has been done.

Japanese Unexamined Patent Publication No. 2009-057400 Japanese Unexamined Patent Publication No. 2016-207554

However, in the non-aqueous electrolyte device, as described above, the film portion ensures the insulation between the laminate material and the lead terminal, but the moisture in the air permeates the film portion and invades the inside of the laminate material. Hydrofluoric acid (hydrofluoric acid) is generated by reacting with the electrolytic solution, which may cause peeling between the film portion and the lead terminal and peeling between the lead terminal and the electrode connection portion. This may lead to deterioration such as a decrease in the output of the non-aqueous electrolyte device and heat generation.

Therefore, it is an object of the present invention to suppress the intrusion of water into the inside of the laminated material, reduce the deterioration due to the invasion of water, and extend the life of the non-aqueous electrolyte device.

First, the tab lead according to the present invention is a tab lead used for a laminated non-aqueous electrolyte device in which at least an electrode and an electrolytic solution or a solid electrolyte are enclosed inside the laminated material, and is formed of a metal material at both ends. A lead terminal provided as an electrode connection portion in which each portion is connected to the electrode and an external terminal portion connected to an external device, and the lead terminal is brought into close contact with the lead terminal from both sides to seal a gap between the lead terminal and the laminate material. A pair of film portions for stopping are provided, and the film portions are formed into three layers of a first resin film, a second resin film, and a third resin film in the thickness direction, and the first resin film is thermally pressure-bonded. The third resin film is brought into close contact with the laminating material by thermal pressure bonding, and the second resin film has a desiccant dispersed inside and the first resin film and the first resin film. The heat resistance is higher than that of the resin film of No. 3, and the end surface of the second resin film on the electrode connection portion side and the end surface of the external terminal portion side on at least one of the first resin film or the third resin film. A covering portion is provided to cover and.

As a result, the desiccant dispersed inside the film portion adsorbs the moisture in the air that permeates the film portion, thereby suppressing the invasion of the moisture into the inside of the laminating material and the covering portion of the second resin. Since each end face of the film is covered, the invasion of water into the second resin film is suppressed and the deactivation rate of the desiccant is reduced.

Secondly, in the tab lead according to the present invention described above, it is desirable that the covering portion is provided by each part of the first resin film and the third resin film.

As a result, the end face of the second resin film is covered with each part of the first resin film and the third resin film, so that the covering portion is less likely to be biased to either the first resin film or the third resin film. Become.

Thirdly, in the tab lead according to the present invention described above, the covering portion is formed by deforming at least one of the first resin film or the third resin film by heat at the time of thermocompression bonding of the film portion. It is desirable to be done.

As a result, the first resin film or the third resin film is brought into close contact with the lead terminal or the laminating material and the covering portion is formed at the time of thermocompression bonding, so that a dedicated step for forming the covering portion is not required. ..

Fourth, in the tab lead according to the present invention described above, when the direction connecting the two end faces of the second resin film is the coating direction and the thickness of the coating portion in the coating direction is the coating thickness, the above-mentioned It is desirable that the coating thickness is 0.1 mm or more.

As a result, the end face is covered with a sufficient amount of the covering portion, so that the deactivation rate of the desiccant contained in the second resin film is reduced.

Fifth, in the above-mentioned tab lead according to the present invention, it is desirable that the content of the desiccant in the second resin film is 5% or more by weight.

As a result, the end face is covered with a sufficiently thick covering portion in a state where a sufficient amount of desiccant is contained.

Sixth, in the tab lead according to the present invention described above, it is desirable that the thickness of the second resin film is 20 μm or more.

As a result, even when the thickness of the first resin film and the third resin film is reduced, the thickness of the second resin film is set to a certain level or more, so that the film portion as a whole is made sufficiently thick.

Seventh, in the tab lead according to the present invention described above, it is desirable that the second resin film is crosslinked.

As a result, the second resin film is crosslinked, so that the strength of the second resin film is increased and the heat resistance is increased.

Eighth, the non-aqueous electrolyte device according to the present invention is a laminated non-aqueous electrolyte device in which at least an electrode and an electrolytic solution or a solid electrolyte are sealed inside a laminate material and a tab lead is provided, and the tab lead is a laminated non-aqueous electrolyte device. A lead terminal formed of a metal material and provided as an electrode connection portion whose both ends are connected to the electrode and an external terminal portion connected to an external device, and the lead terminal and the lead terminal which are brought into close contact with the lead terminal from both sides. It is provided with a pair of film portions for sealing the gaps with the laminating material, and the film portions are formed into three layers of a first resin film, a second resin film, and a third resin film in the thickness direction, and the first resin film is formed. The resin film 1 is brought into close contact with the lead terminal by hot crimping, the third resin film is brought into close contact with the laminating material by hot crimping, and the second resin film has a desiccant dispersed inside and the first. The heat resistance is higher than that of the resin film 1 and the third resin film, and the first resin film or at least one of the third resin films has an end face on the electrode connection portion side of the second resin film. A covering portion is provided so as to cover the end surface on the external terminal portion side.

As a result, in the tab lead, the desiccant dispersed inside the film portion adsorbs the moisture in the air that permeates the film portion, so that the invasion of the moisture into the inside of the laminating material is suppressed, and the covering portion suppresses the invasion of the moisture. Since each end face of the resin film 2 is covered, the invasion of water into the second resin film is suppressed and the deactivation rate of the desiccant is reduced.

According to the present invention, deterioration of the non-aqueous electrolyte device due to the intrusion of water is reduced, and the life of the non-aqueous electrolyte device can be extended.

FIGS. 2 to 12 show an embodiment of the present invention, and this figure is a front view of a non-aqueous electrolyte device. FIG. 3 is a cross-sectional view taken along the line II-II of FIG. It is a perspective view of a tab lead. It is a conceptual diagram for demonstrating the deactivation state of a desiccant. It is a conceptual diagram which shows the structure of a film part. It is a conceptual diagram which shows the state before the film part is thermocompression bonded to the lead terminal. It is a conceptual diagram which shows the state which the film part is thermocompression bonded to the lead terminal and the laminating material, and the covering part is formed. It is a conceptual diagram which shows the example which the whole covering part was formed only by the covering part of a 3rd resin film. It is a conceptual diagram which shows the example which the size of the cover part of the 1st resin film and the cover part of a 3rd resin film is different in a covering part. Along with FIGS. 11 and 12, data on the function of the covering portion is shown, and this figure is a graph showing the results of measuring the barrier capacity when the desiccant of the segment is inactivated. It is a graph which shows the result of having measured the deactivation period until all the desiccants contained in the 2nd resin film became deactivated with respect to the different coating thickness of the coating part. It is a graph which shows the life of a non-aqueous electrolyte device.

Hereinafter, embodiments for carrying out the tab lead and non-aqueous electrolyte devices of the present invention will be described with reference to the accompanying drawings.

<Outline configuration of non-aqueous electrolyte device>
First, a schematic configuration of a lithium ion battery will be described as an example of a laminated non-aqueous electrolyte device in which a tab lead is used (see FIGS. 1 and 2). The scope of application of the non-aqueous electrolyte device of the present invention is not limited to the lithium ion battery, and the present invention can be applied to other non-aqueous electrolyte devices such as a laminated lithium ion capacitor.

In the following description, the direction in which the tab lead is projected in the non-aqueous electrolyte device (lithium ion battery) is upward, and the front-back, up-down, left-right directions are shown. However, the front-back, up-down, left-right directions shown below are for convenience of explanation, and are not limited to these directions in the practice of the present invention.

The non-aqueous electrolyte device (lithium ion battery) 100 includes a bag-shaped laminated material 101, each part enclosed inside the laminated material 101, and tab leads 1, 1 in which a part thereof is located inside the laminated material 101. (See FIG. 1).

The laminated material 101 has a tubular shape whose upper end is formed as a sealing portion 102. The laminated material 101 has, for example, a three-layer structure, and an outer surface layer 101a and an inner surface layer 101b formed of a resin material are laminated on both sides of the metal layer 101c (see FIG. 2). For example, polyethylene terephthalate is used as the outer surface layer 101a, polypropylene is used as the inner surface layer 101b, and aluminum is used as the metal layer 101c, for example.

An electrolytic solution 103, a positive electrode 104, a negative electrode 105, and a separator 106 are enclosed inside the laminated material 101. The positive electrode 104 and the negative electrode 105 are immersed in the electrolytic solution 103, and the space in which the positive electrode 104 is arranged and the space in which the negative electrode 105 is arranged are partitioned by the separator 106. As the positive electrode 104, for example, aluminum is used, and as the negative electrode 105, for example, copper is used. A solid electrolyte may be used instead of the electrolytic solution 103.

<Tab lead configuration>
Next, the configuration of the tab lead 1 will be described (see FIGS. 2 to 6).

The tab lead 1 is composed of a lead terminal 2 made of a metal material and a pair of film portions 3 and 3 that are in close contact with the lead terminal 2 from both sides (see FIG. 2). A part of the tab lead 1 is brought into close contact with the sealing portion 102, and a portion on the upper end side protrudes from the laminated material 101.

The lead terminal 2 is formed in a thin plate shape having a thickness of, for example, 50 μm to 3000 μm. The lower end of the lead terminal 2 is formed as an electrode connecting portion 2a and is connected to the positive electrode 104 or the negative electrode 105. The upper end portion of the lead terminal 2 is formed as an external terminal portion 2b exposed to the outside from the laminated material 101, and power is supplied from the non-aqueous electrolyte device 100 by connecting a connection terminal (not shown) of an external device to the external terminal portion 2b. Taken out.

As the lead terminal 2, for example, aluminum or copper is used, and the surface is nickel-plated. However, in the case of aluminum, plating may not be applied. The portion of the lead terminal 2 located inside the laminated material 101 may be provided with a corrosion-resistant film that suppresses corrosion of the lead terminal 2.

The film portion 3 is in close contact with both sides of the lead terminal 2 in the thickness direction in a state where the left and right end portions protrude from the lead terminal 2 (see FIG. 3). The portion of the film portion 3 in close contact with the lead terminal 2 is referred to as the close contact portion 4. Both ends of the film portion 3 in the left-right direction are mating portions 5 and 5 in which the end portions facing each other are bonded to each other with the film portions 3 and 3 in close contact with both sides of the lead terminal 2.

A particulate desiccant 6 is dispersed (contained) inside the film portion 3. In addition to the desiccant 6, the film portion 3 may contain additives such as a cross-linking agent and an antioxidant.

The film portion 3 has three layers of a first resin film 7, a second resin film 8 and a third resin film 9 in the thickness direction, and the first resin film 7 is brought into close contact with the lead terminal 2 by thermal pressure bonding. The third resin film 9 is brought into close contact with the sealing portion 102 of the laminating material 101 by thermal pressure bonding. In the film portion 3, the inner surface 7a of the first resin film 7 is in close contact with the lead terminal 2, and the outer surface 9a of the third resin film 9 is in close contact with the inner surface layer 101b.

In the laminated portion of the first resin film 7, the second resin film 8, and the third resin film 9, the thicknesses of the first resin film 7 and the third resin film 9 are made the same, for example. , The thickness of the second resin film 8 is made thicker than the thickness of the first resin film 7 and the third resin film 9. For example, the first resin film 7 and the third resin film 9 have a thickness of 10 μm to 50 μm, and the second resin film 8 has a thickness of 20 μm to 50 μm.

In the film portion 3, the base resin of the first resin film 7, the second resin film 8 and the third resin film 9 is a polyolefin-based resin in which moisture is difficult to permeate among the resins, for example, polypropylene (acid-modified). It is made of polypropylene). The first resin film 7 and the third resin film 9 are provided as an adhesion layer, the second resin film 8 is provided as a heat-resistant layer, and the second resin film 8 is a first resin film 7 and a third resin film 7. It has higher heat resistance than the resin film 9. The desiccant 6 and the cross-linking agent are dispersed in the second resin film 8.

As the desiccant 6, a material having a water catching property that physically adsorbs water, for example, zeolite, stearite, silica, or the like is used. Since zeolite, stearite, and silica can release the adsorbed water to the atmosphere by heating, it is not necessary to consider the decrease in water catching power caused by the desiccant 6 adsorbing water in the manufacturing process. It is possible to secure a good manufacturing condition of the film portion 3. However, as the desiccant 6, both a material that physically adsorbs water and a material that chemically adsorbs water may be used.

As the desiccant 6, a material having a high water catching property that chemically adsorbs water, for example, calcium oxide may be used. The particle size of calcium oxide is, for example, 30 μm or less, and the weight of calcium oxide is, for example, 10% or more in terms of the content ratio in the second resin film 8 with respect to the whole of the second resin film 8. Has been done. Further, as a material of the desiccant 6 having a water catching property that chemically adsorbs water, strontium oxide, barium oxide, or magnesium oxide may be used instead of calcium oxide. Further, an oxide of an alkaline earth metal typified by calcium oxide, an oxide of an alkali metal, a mixture thereof, or a composite oxide may be used.

Since calcium oxide has a particularly high water replenishment upper limit and is easily available and handled, the use of calcium oxide as the desiccant 6 can ensure sufficient water catching and reduce the production cost. The same effect can be obtained by using strontium oxide, barium oxide, or magnesium oxide instead of calcium oxide.

Further, since the oxide of the alkaline earth metal has a higher water catching upper limit than the material that catches water by physical adsorption, the oxide of the alkaline earth metal is used as the desiccant 6 and is contained in the film portion 3. The amount of the desiccant 6 can be reduced, and the manufacturing cost can be reduced while ensuring sufficient water catching. The same applies by using a mixture or composite oxide of an alkali metal oxide, an alkali metal oxide, or an alkaline earth metal oxide as the desiccant 6 instead of the alkaline earth metal oxide. The effect can be obtained.

Further, it is desirable that the desiccant 6 has a particle size of 30 μm or less. As a result, when thermocompression bonding is performed, the gap between the lead terminal 2 and the laminated material 101 is sealed while the film portion 3 maintains the thickness of at least the particle size of the desiccant 6. Therefore, a good insulating state between the lead terminal 2 and the laminated material 101 can be ensured. However, when the desiccant 6 having a small particle size is used, the thickness of the film portion 3 can be reduced.

Furthermore, it is desirable that the weight of the desiccant 6 is 30% or less with respect to the weight of the film portion 3. As a result, poor dispersion and aggregation of the desiccant 6 are less likely to occur in the film portion 3, so that a good adhesion state between the lead terminal 2 and the laminating material 101 in the film portion 3 can be ensured.

As described above, the film portion 3 contains the desiccant 6, but it is also possible to configure the film portion 3 so as not to contain the desiccant 6. However, in the case where the film portion 3 does not contain the desiccant 6, moisture penetrates according to the water vapor permeability of the resin forming the film portion 3, and the invaded moisture is encapsulated inside the laminate material 101. It may react with the liquid 103 and shorten the life of the non-aqueous electrolyte device 100. In particular, when the non-aqueous electrolyte device 100 is used, for example, as an in-vehicle power source, it preferably satisfies a useful life (life) of at least 8 years, and has a useful life (life) of 15 years in the future. In the case of a configuration in which the desiccant 6 is not dispersed, these useful lives may not be satisfied.

Therefore, by incorporating the desiccant 6 in the film portion 3, moisture is adsorbed by the desiccant 6 to extend the life, but if the desiccant 6 is contained in the entire film portion 3, the desiccant 6 is contained. There is a possibility that the adhesion between the film portion 3 and the lead terminal 2 and the laminating material 101 is lowered due to the inclusion of the film portion 3, and sufficient adhesion between the film portion 3 and the lead terminal 2 and the laminating material 101 cannot be ensured. ..

Therefore, in the tab lead 1, the first resin film 7 and the third resin film 9 are configured so that the desiccant 6 is not contained, and sufficient adhesion between the film portion 3 and the lead terminal 2 and the laminating material 101 is ensured. In the above, the second resin film 8 is configured to contain the desiccant 6. With such a configuration, the moisture entering the film portion 3 can be adsorbed by the desiccant 6 and the invasion of the moisture into the inside of the laminating material 101 can be suppressed, and the film portion 3, the lead terminal 2 and the lead terminal 2 can be suppressed. It is possible to extend the life of the non-aqueous electrolyte device 100 while ensuring sufficient adhesion to the laminated material 101.

On the other hand, if a part of the second resin film 8 containing the desiccant 6 is exposed to the air, the moisture in the air easily invades the second resin film 8, so that the film is dried. The speed at which the agent 6 becomes inactive may increase, and it may not be possible to achieve a sufficiently long life.

The deactivated state of the desiccant 6 is a state in which the amount of water adsorbed to each particle of the desiccant 6 is maximized and no more water can be adsorbed in each particle, and the deactivated state is air. It occurs in order from the exposed part (segment) with respect to (see FIG. 4).

For example, if the portion where the desiccant 6 is arranged at regular intervals is set as a segment and the segment A, the segment B, the segment C, ... .. When the amount of water adsorbed on each particle of the segment A becomes maximum due to the invasion of water and becomes saturated, the desiccant 6 in the segment A becomes inactive. At this time, the deactivated desiccant 6 is in a state of allowing moisture to pass through, so that the moisture easily passes through the segment A according to the volume occupied by the desiccant 6 in the segment A, and the moisture flows from the segment A to the segment B. Invade towards. Therefore, due to the further intrusion of water, the desiccant 6 in the segment B becomes inactive and the water easily passes through the segment B, and in order, the desiccant 6 in each segment becomes inactive and the water in each segment. It becomes easy to pass through.

Therefore, in the film portion 3, in order to suppress the deactivation rate of the desiccant 6 in the second resin film 8, the end faces 8a and 8a in the vertical direction of the second resin film 8 are the first resin film 7, respectively. And each part of the third resin film 9 (see FIG. 2). Therefore, the film portion 3 is provided with covering portions 10 and 10 that cover the end faces 8a and 8a, respectively.

When the direction (vertical direction) connecting the end faces 8a and 8a of the second resin film 8 is the covering direction, the covering portions 10 and 10 are provided at both ends of the film portion 3 in the covering direction. At this time, assuming that the thickness of the covering portion 10 in the covering direction is the covering thickness H, the covering thickness H of the covering portion 10 is, for example, 0.1 mm or more (see FIG. 5).

As described above, the first resin film 7 has a portion constituting a part of the covering portion 10, and the first resin film 7 is laminated on the second resin film 8 in the thickness direction. And the covering portions 7c and 7c which are continuous at both ends of the laminated portion 7b and form a part of the covering portions 10 and 10, respectively. Further, the third resin film 9 also has a portion constituting each part of the covering portion 10, and the third resin film 9 is laminated with the laminated portion 9b laminated on the second resin film 8 in the thickness direction. Both ends of the portion 9b are continuously provided with covering portions 9c and 9c which form each part of the covering portions 10 and 10.

<Formation of covering>
Next, the formation of the covering portions 10 and 10 will be described (see FIGS. 6 to 9). The tab lead 1 has a pair of film portions 3 and 3, but only one film portion 3 will be described below for the sake of simplicity.

In the step before the film portion 3 is thermally pressure-bonded to the lead terminal 2, for example, the gamma ray whose irradiation amount is controlled is the whole of the first resin film 7, the second resin film 8, and the third resin film 9. The second resin film 8 is crosslinked by irradiating only the second resin film 8. The film portion 3 is brought into a state of having high heat resistance to the first resin film 7 and the third resin film 9 by cross-linking the second resin film 8, and is combined with the lead terminal 2 in the subsequent steps. It is thermocompression bonded to the laminating material 101.

The covering portions 10 and 10 are formed as follows when the film portion 3 is adhered to the lead terminal 2 by thermocompression bonding and when the film portion 3 is adhered to the laminating material 101 by thermocompression bonding (FIGS. 6 and FIG. 7).

First, the film portion 3 is thermocompression-bonded to the lead terminal 2 so that the first resin film 7 is brought into close contact with the lead terminal 2. However, in the state before the thermocompression bonding, for example, the film portion 3 has substantially the same thickness. The first resin film 7, the second resin film 8, and the third resin film 9 are laminated in the thickness direction (see FIG. 6). At this time, the thicknesses of the first resin film 7, the second resin film 8 and the third resin film 9 are, for example, 40 μm to 60 μm, and the first resin film 7, the second resin film 8 and the second resin film 8 and the first resin film 7 have a thickness of 40 μm to 60 μm. The width of the resin film 9 of No. 3 in the coating direction is the same, and the end faces 8a and 8a of the second resin film 8 are exposed.

When the first resin film 7 is bonded to the lead terminal 2 and brought into close contact with the lead terminal 2 by thermocompression bonding, the tab lead 1 is formed, and then the tab lead 1 is thermocompression bonded to the laminating material 101 to form the third resin film 9. It is in close contact with the sealing portion 102 (see FIG. 7). In this way, the first heat crimping step in which the first resin film 7 is brought into close contact with the lead terminal 2 by hot crimping and the second hot crimping in which the third resin film 9 is brought into close contact with the sealing portion 102 by hot crimping. In the step, the first resin film 7, the second resin film 8, and the third resin film 9 are deformed (melted) by thermal pressure bonding, and each part of the first resin film 7 and the third resin are formed. Each part of the film 9 wraps around the end faces 8a and 8a to form the covering portions 10 and 10. A part of the first resin film 7 that wraps around to the end faces 8a and 8a is a covering portion 7c and 7c, respectively, and a part of the third resin film 9 that wraps around to the end faces 8a and 8a. Are the covering portions 9c and 9c, respectively.

At this time, since the second resin film 8 is cross-linked, the degree of cross-linking of the second resin film 8 is made larger than that of the first resin film 7 and the third resin film 9, and the second resin film 8 is The amount of deformation due to thermal pressure bonding is smaller and the strength is higher than that of the first resin film 7 and the third resin film 9, and the heat resistance is higher than that of the first resin film 7 and the third resin film 9. Further, in the second thermocompression bonding step, the third resin film 9 is more easily deformed than the first resin film 7, and the covering portion 9c is more likely to be larger than the covering portion 7c in the thickness direction of the film portion 3.

In a state where the first resin film 7 is in close contact with the lead terminal 2 and the third resin film 9 is in close contact with the sealing portion 102, as described above, the first resin film 7 and the third resin film 9 are in close contact with each other. The thickness of the second resin film 8 is changed from 10 μm to 50 μm, and the thickness of the second resin film 8 is changed from 20 μm to 50 μm.

In the tab lead 1, the entire covering portion 10 covering the end face 8a may be formed only by the covering portion 9c of the third resin film 9 (see FIG. 8).

Further, in the above, the size (dimensions) of the portion covering the end face 8a in the covering portion 7c of the first resin film 7 and the covering portion 9c of the third resin film 9 in the covering direction is the same. An example (see FIG. 7) is shown for convenience, but the degree of deformation of the first resin film 7 and the third resin film 9 is different in the first heat crimping step and the second heat crimping step, and the coating is performed. In the direction, the covering portion 7c of the first resin film 7 may be larger than the covering portion 9c of the third resin film 9 (see FIG. 9). In this case, the thickness of the covering portion 9c in the covering direction is made smaller than the thickness of the covering portion 7c in the covering direction.

In the tab lead 1 configured as described above, since the desiccant 6 is dispersed in the second resin film 8, the moisture in the air entering the inside of the film portion 3 is adsorbed by the desiccant 6 and laminated. The invasion of water into the inside of the material 101 is suppressed. Therefore, the deterioration of the non-aqueous electrolyte device 100 due to the intrusion of water is reduced, and the life of the non-aqueous electrolyte device 100 can be extended. Further, the desiccant 6 is made of a material that is not easily crushed, and the film portion 3 maintains a thickness that prevents contact between the lead terminal 2 and the laminating material 101 even when pressure is applied during heat welding. Good insulation between the terminal 2 and the laminated material 101 can be ensured.

Further, the film portion 3 is formed of a polyolefin-based resin. Therefore, the effect of suppressing the invasion of water into the inside of the laminated material 101 can be enhanced.

<Calculation results related to the function of the covering part>
Next, the calculation results and the like regarding the functions of the covering portion 10 described above will be described (see FIGS. 10 to 12).

FIG. 10 covers the ability (moisture barrier ability) of suppressing the invasion of water in the segment A when the desiccant 6 of the segment A in the second resin film 8 shown in FIG. 4 is inactivated. This is the data calculated when the coating thickness H of the portion 10 is different. That is, even when the desiccant 6 is inactive, the invasion of water is suppressed by the material itself of the second resin film 8, so the ability to suppress the invasion of water at this time is calculated.

In FIG. 10, the horizontal axis is the content (weight ratio) of the desiccant 6 with respect to the second resin film 8, and the vertical axis is the barrier capacity. The barrier capacity was set to 100% in a state where the content of the second resin film 8 was 0% and the desiccant 6 was not contained.

As shown in FIG. 10, the barrier capacity decreases as the content of the desiccant 6 increases regardless of the thickness of the coating thickness H, but increases as the coating thickness H increases, resulting in deactivation. Even in the state, the result was obtained that the invasion of water was sufficiently suppressed as the coating thickness H became thicker.

Therefore, by providing the coating portion 10 in the film portion 3, the invasion of water into the film portion 3 is suppressed even in the deactivated state of the desiccant 6, and the coating portion 10 has a high function of suppressing the invasion of water. I understand. It was also found that even if the coating thickness H of the covering portion 10 is about 0.1 mm, a sufficient effect of suppressing the intrusion of water can be obtained as compared with the case where the covering portion 10 is not provided.

FIG. 11 shows the second resin film 8 of the desiccant 6 with respect to the deactivation period until all the desiccants 6 contained in the second resin film 8 are inactivated for different coating thicknesses H. It is the data calculated when the content ratio (weight ratio) with respect to is different.

In FIG. 11, the horizontal axis is the coating thickness H, and the vertical axis is the inactivation period until all the desiccants 6 are inactivated.

As shown in FIG. 11, the deactivation period becomes longer as the coating thickness H becomes thicker regardless of the high content of the desiccant 6, and as the coating thickness H becomes thicker and the content of the desiccant 6 increases. The result was longer. In particular, when the coating thickness H is 0.1 mm or more and the content of the desiccant 6 is 20% or more, the result that the deactivation period is 15 years or more is satisfied.

The inactivation period shown in FIG. 11 is a period until all the desiccants 6 contained in the second resin film 8 are in an inactivated state, and as shown in the data of FIG. 10 in the tab lead 1. In addition, since the invasion of water is suppressed by the material itself of the film portion 3, the life of the non-aqueous electrolyte device 100 is longer than the inactivation period. That is, the life of the non-aqueous electrolyte device 100 takes into consideration the function of suppressing the intrusion of water by the material itself of the film portion 3 in addition to the fact that all the desiccants 6 contained in the second resin film 8 are inactive. However, since it is a period until the water reacts with the electrolytic solution 103 and interferes with the extraction of electric power, it is generally a period obtained by adding a period of about 8 years to the inactivation period.

FIG. 12 is data obtained by calculating the life of the non-aqueous electrolyte device 100 in consideration of such matters.

In FIG. 12, the horizontal axis is the coating thickness H, and the vertical axis is the period of the life of the non-aqueous electrolyte device 100.

As shown in FIG. 12, the life of the non-aqueous electrolyte device 100 becomes longer as the coating thickness H becomes thicker regardless of the high content of the desiccant 6, and the coating thickness H becomes thicker and the content of the desiccant 6 becomes thicker. The result was that the higher the value, the longer the value. In particular, when the coating thickness H is 0.1 mm or more and the content of the desiccant 6 is 5% or more, the result is obtained that the life of the non-aqueous electrolyte device 100 satisfies the more desirable period of 15 years or more.

<Summary>
As described above, in the tab lead 1 and the non-aqueous electrolyte device 100, the first resin film 7 is brought into close contact with the lead terminal 2 by hot crimping, and the third resin film 9 is brought into close contact with the laminate material 101 by hot crimping. The second resin film 8 has a desiccant 6 dispersed inside, and has higher heat resistance than the first resin film 7 and the third resin film 9, so that the first resin film 7 or the third resin film 8 has a heat resistance higher than that of the first resin film 7 and the third resin film 9. At least one of the resin films 9 is provided with covering portions 10 and 10 that cover the end faces 8a and 8a of the second resin film 8, respectively.

Therefore, the drying agent 6 dispersed inside the film portion 3 adsorbs the moisture in the air passing through the film portion 3, so that the invasion of the moisture into the inside of the laminating material 101 is suppressed and the covering portion 10 suppresses the invasion of the moisture. Since the end faces 8a and 8a of the second resin film 8 are covered, the invasion of water into the second resin film 8 is suppressed and the deactivation rate of the desiccant 6 is reduced. As a result, deterioration of the non-aqueous electrolyte device 100 due to the intrusion of water is reduced, and the life of the non-aqueous electrolyte device 100 can be extended.

Further, the covering portion 10 is provided by the covering portion 7c of the first resin film 7 and the covering portion 9c of the third resin film 9, so that the end surface 8a of the second resin film 8 is the first resin film 7. Since it is covered with each part of the third resin film 9 and the third resin film 9, the covering portion 10 is less likely to be biased to either the first resin film 7 or the third resin film 9, and the end face 8a is surely covered with the desiccant 6. It is possible to suppress the reduction of water catching performance.

Further, the covering portion 10 is formed by deforming at least one of the first resin film 7 and the third resin film 9 by heat at the time of thermocompression bonding of the film portion 3.

Therefore, at the time of thermocompression bonding, the first resin film 7 or the third resin film 9 is brought into close contact with the lead terminal 2 or the laminating material 101 and the covering portion 10 is formed, so that it is dedicated to forming the covering portion 10. The life of the non-aqueous electrolyte device 100 can be extended by suppressing the intrusion of moisture into the inside of the laminated material 101 while reducing the manufacturing cost without requiring a step.

The covering portion 10 is formed by forming the first resin film 7 and the third resin film 9 separately from the second resin film 8, which are formed in advance in a shape having a portion constituting each part of the covering portion 10. However, it can also be formed by attaching the first resin film 7 and the third resin film 9 to the second resin film 8 in the subsequent steps.

However, as described above, when the covering portion 10 is formed during thermal pressure bonding, the first resin film 7 and the third resin film 9 are previously formed of each part of the covering portion 10. It is not necessary to form the shape having The covering portion 10 is formed at the same time when the material 101 is thermally pressure-bonded.

Therefore, by forming the covering portion 10 at the time of thermocompression bonding, the manufacturing time of the tab lead 1 and the non-aqueous electrolyte device 100 is significantly shortened, and the manufacturing cost is significantly reduced, thereby greatly improving the productivity. be able to. In particular, a complicated structure for covering the second resin film 7 can be easily formed by a process similar to a general process for forming the tab lead 1, and a complicated structure for covering the second resin film 7 can be easily formed. It is possible to greatly improve the productivity at the time of forming.

Furthermore, since the end face 8a is covered with a sufficient amount of the coating portion 10 by setting the coating thickness H of the coating portion 10 to 0.1 mm or more, the desiccant 6 contained in the second resin film 8 The deactivation rate of the non-aqueous electrolyte device 100 can be further extended.

Further, by setting the content of the desiccant 6 in the second resin film 8 to 5% or more by weight, the end face 8a is covered with a sufficient thickness while the desiccant 6 is contained in a sufficient amount. Since it is covered with 10, it is possible to reduce the deactivation rate of the desiccant 6 while ensuring the high water catching function of the desiccant 6 contained in the second resin film 8.

Further, by making the thickness of the second resin film 8 20 μm or more, the second resin film 8 is more than a certain amount even when the thicknesses of the first resin film 7 and the third resin film 9 are thinned. Therefore, the film portion 3 has a sufficient thickness as a whole, and good insulation by the film portion 3 can be ensured.

In addition, since the second resin film 8 is crosslinked, the strength of the second resin film 8 is increased and the heat resistance is increased, so that the high strength of the film portion 3 as a whole can be ensured. At the same time, high heat resistance can be ensured.

In the non-aqueous electrolyte device 100 described above, the tab leads 1 and 1 connected to the positive electrode 104 or the negative electrode 105 are both projected upward from the laminated material 101, but are connected to the positive electrode 104 or the negative electrode 105. One of the tab leads 1 and 1 may be projected upward from the laminated material 101, and the other may be projected downward from the laminated material 101.

100 Non-aqueous electrolyte device 101 Laminate material 103 Electrolyte 104 Positive electrode (electrode)
105 Negative electrode (electrode)
1 Tab lead 2 Lead terminal 2a Electrode connection part 2b External terminal part 3 Film part 6 Drying agent 7 First resin film 7c Covering part 8 Second resin film 8a End face 9 Third resin film 9c Covering part 10 Covering part

Claims (8)

A tab lead used in a laminated non-aqueous electrolyte device in which at least an electrode and an electrolytic solution or a solid electrolyte are enclosed inside a laminated material.
An electrode connection portion formed of a metal material and having both ends connected to the electrodes, a lead terminal provided as an external terminal portion connected to an external device, and a lead terminal.
It is provided with a pair of film portions that are in close contact with the lead terminal from both sides and seal the gap between the lead terminal and the laminating material.
The film portion is formed into three layers of a first resin film, a second resin film, and a third resin film in the thickness direction, and the first resin film is brought into close contact with the lead terminal by thermal pressure bonding to be brought into close contact with the lead terminal. The resin film of No. 1 is adhered to the laminate material by thermal pressure bonding.
The second resin film has a desiccant dispersed inside and has higher heat resistance than the first resin film and the third resin film.
A tab lead provided on at least one of the first resin film or the third resin film with a covering portion covering the end surface of the second resin film on the electrode connection portion side and the end surface on the external terminal portion side. The tab lead according to claim 1, wherein the covering portion is provided by each part of the first resin film and the third resin film. The tab lead according to claim 1 or 2, wherein the covering portion is formed by deforming at least one of the first resin film or the third resin film by heat at the time of thermocompression bonding of the film portion. When the direction connecting the two end faces of the second resin film is the coating direction and the thickness of the coating portion in the coating direction is the coating thickness.
The tab lead according to claim 1, claim 2 or claim 3, wherein the coating thickness is 0.1 mm or more. The tab lead according to claim 4, wherein the content of the desiccant in the second resin film is 5% or more by weight. The tab lead according to claim 1, claim 2, claim 3, claim 4 or claim 5, wherein the thickness of the second resin film is 20 μm or more. The tab lead according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6, wherein the second resin film is crosslinked. A laminated non-aqueous electrolyte device in which at least an electrode and an electrolytic solution or a solid electrolyte are enclosed inside a laminated material and a tab lead is provided.
The tab lead is
An electrode connection portion formed of a metal material and having both ends connected to the electrodes, a lead terminal provided as an external terminal portion connected to an external device, and a lead terminal.
It is provided with a pair of film portions that are in close contact with the lead terminal from both sides and seal the gap between the lead terminal and the laminating material.
The film portion is formed into three layers of a first resin film, a second resin film, and a third resin film in the thickness direction, and the first resin film is brought into close contact with the lead terminal by thermal pressure bonding to be brought into close contact with the lead terminal. The resin film of No. 1 is adhered to the laminate material by thermal pressure bonding.
The second resin film has a desiccant dispersed inside and has higher heat resistance than the first resin film and the third resin film.
A non-water-free coating portion is provided on at least one of the first resin film or the third resin film so as to cover an end surface of the second resin film on the electrode connection portion side and an end surface on the external terminal portion side. Electrolyte device.

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