Water catching member and non-aqueous electrolyte device

Abstract

To secure a high performance of catching water on the basis of an excellent manufacturing performance attained.SOLUTION: The present invention relates to a water catching member in which a desiccant agent is dispersed in a base material formed by a resin material. The volume fraction of the desiccant agent is at least 6.5vol% and is 39.3vol% at a maximum.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a water-trapping member that adsorbs moisture by a desiccant dispersed therein, and a nonaqueous electrolyte device including the water-trapping member. [Background technology]

[0002] In recent years, non-aqueous electrolyte devices such as lithium ion batteries and lithium ion capacitors have been used as in-vehicle batteries, storage batteries, etc. Known non-aqueous electrolyte devices include those in which electrodes (positive and negative electrodes) and an electrolytic solution or a solid electrolyte are enclosed inside an exterior body such as a laminate material or an outer casing, and power is extracted through a connection terminal attached to the exterior body.

[0003] In such a nonaqueous electrolyte device, even if the exterior body is sealed, moisture in the air may penetrate into the interior of the exterior body. In addition, for example, moisture attached to the electrodes, the electrolyte, the surface of the exterior body, etc. may be brought into the interior of the exterior body during the assembly process of the nonaqueous electrolyte device. If moisture penetrates into the interior of the exterior body, hydrofluoric acid (hydrofluoric acid) may be generated by the reaction of the moisture with the electrolyte, hydrolysis of the electrolyte solvent due to the moisture, and dissolution of the passive film of the electrode may occur, which may lead to deterioration of the nonaqueous electrolyte device, such as a decrease in output.

[0004] For this reason, some of the above-mentioned nonaqueous electrolyte devices include a moisture capture member in which a desiccant is dispersed inside a resin material serving as a base material, and the moisture is absorbed by the moisture capture member (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-235255 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, it is desirable for the above-mentioned moisture capture member to have high moisture capture performance (moisture capture speed) in order to minimize the reaction between moisture and the electrolyte, etc. Generally, the moisture capture speed increases as the proportion of the desiccant in the moisture capture member increases, but the greater the proportion of the desiccant, the more easily the desiccant particles tend to aggregate with each other, which may result in a decrease in the manufacturability of the moisture capture member.

[0007] Therefore, an object of the present invention is to ensure high water catching performance while ensuring good manufacturability of the water catching member. [Means for solving the problem]

[0008] The water capture member of the present invention is a water capture member in which a desiccant is dispersed inside a base material formed from a resin material, and the volume fraction of the desiccant is equal to or greater than 6.5 vol% and equal to or less than 39.3 vol%.

[0009] This ensures that the desiccant is well dispersed in the moisture capture member.

[0010] Furthermore, the nonaqueous electrolyte device according to the present invention comprises an exterior body in which at least electrodes and an electrolytic solution or a solid electrolyte are enclosed, connection terminals electrically connected to the electrodes, and a moisture capture member in which a desiccant is dispersed inside a base material formed from a resin material, and the volume fraction of the desiccant in the moisture capture member is set to 6.5 vol% or more and 39.3 vol% or less.

[0011] This ensures that the desiccant is well dispersed in the moisture capture member. Effect of the Invention

[0012] According to the present invention, since the desiccant is kept well dispersed in the water capture member, it is possible to ensure high water capture performance while ensuring good manufacturability of the water capture member. [Brief description of the drawings]

[0013] [Figure 1] 2 to 4, this figure shows an embodiment of the present invention, and is a perspective view of a non-aqueous electrolyte device. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 4 is an enlarged cross-sectional view showing a connection terminal and the like. [Figure 4] FIG. 11 is a cross-sectional view showing an example in which a positive electrode current collector and a negative electrode current collector are attached to the upper end portion of an electrode body. [Diagram 5] 4 is a conceptual diagram showing particles of a desiccant in a moisture capture member. FIG. [Figure 6] 4 is a conceptual diagram showing particle spacing of a desiccant in a moisture capture member. FIG. [Figure 7] FIG. 1 shows a second embodiment of the present invention, and is a cross-sectional view of a nonaqueous electrolyte device viewed from the front and rear. [Figure 8] 9 and 10 show a third embodiment of the present invention, and this figure is a cross-sectional view of a nonaqueous electrolyte device as viewed from the front and rear directions. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 9 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 13 shows a fourth embodiment of the present invention together with FIG. 12, and is a cross-sectional view of a nonaqueous electrolyte device as viewed from the left and right. [Figure 12] FIG. 2 is a horizontal cross-sectional view of a non-aqueous electrolyte device. [Figure 13] FIG. 15 shows a fifth embodiment of the present invention together with FIG. 14, and is a front view of a nonaqueous electrolyte device. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the water capture member and nonaqueous electrolyte device of the present invention will be described with reference to the accompanying drawings.

[0015] In the following, a lithium ion battery will be described as an example of the nonaqueous electrolyte device, however, the scope of application of the nonaqueous electrolyte device of the present invention is not limited to lithium ion batteries, and the present invention can also be applied to other nonaqueous electrolyte devices such as lithium ion capacitors.

[0016] The nonaqueous electrolyte device of the present invention is provided with two connection terminals protruding from an outer casing. In the following description, the direction in which the connection terminals protrude from the outer casing is defined as the up direction, the direction in which the two connection terminals are arranged is defined as the left-right direction, and the direction perpendicular to both the up-down direction and the left-right direction is defined as the front-back direction, and the directions of up-down, up-down, front-back, left-right and right are indicated. However, the directions of up-down, up-down, front-back, left-right and right shown below are for the convenience of explanation, and the implementation of the present invention is not limited to these directions.

[0017] In the following description, moisture brought into the inside of the outer casing during the assembly process of the nonaqueous electrolyte device may be referred to as intrinsic moisture, and moisture that invades the inside of the outer casing after assembly may be referred to as exogenous moisture.

[0018] <Non-aqueous electrolyte device according to the first embodiment> First, a nonaqueous electrolyte device 1 according to a first embodiment will be described (see FIGS. 1 to 4).

[0019] The nonaqueous electrolyte device (lithium ion battery) 1 has a case body 2 with an opening formed at the upper end and a cover 3 that closes the opening of the case body 2 (see Figs. 1 and 2). The case body 2 and the cover 3 form an outer casing (exterior body) 4, and the internal space of the outer casing 4 is formed as an enclosed space 5.

[0020] The case body 2 has a rectangular bottom surface portion 6 facing in the vertical direction, and a peripheral surface portion 7 protruding upward from the outer periphery of the bottom surface portion 6. The peripheral surface portion 7 is made up of a front surface portion 8 and a rear surface portion 9 facing in the front-rear direction, and a pair of side surfaces 10 facing in the left-right direction. However, the case body 2 may have a circular bottom surface portion and be formed into a cylindrical shape as a whole. The case body 2 is formed, for example, from a metal material.

[0021] The cover 3 has an outer shape formed in a plate shape having approximately the same size as the bottom surface portion 6. The cover 3 is formed of, for example, a metal material and is joined to the upper end of the peripheral surface portion 7 by, for example, welding. Two terminal insertion holes 3a are formed in the cover 3, which are spaced apart from each other on the left and right sides and penetrate vertically, and two connection terminals 11 are attached in a state of being inserted into the terminal insertion holes 3a. One connection terminal 11 is provided as a positive electrode connection terminal 11a connected to a positive electrode described later, and the other connection terminal 11 is provided as a negative electrode connection terminal 11b connected to a negative electrode described later.

[0022] The connection terminal 11 has, for example, an electrode connection portion 12 formed in a disk shape and a shaft-like portion 13 protruding upward from the center of the electrode connection portion 12 (see FIG. 3). A screw groove (not shown) is formed in the shaft-like portion 13. The connection terminal 11 is attached to the cover 3 by a nut 15 via an insulating member 14 with the shaft-like portion 13 inserted into the terminal insertion hole 3a. With the connection terminal 11 attached to the cover 3, the electrode connection portion 12 is located in the enclosed space 5.

[0023] A sealing member 16 is disposed between the cover 3 and the electrode connection portion 12. The sealing member 16 is made of an elastic material, and an O-ring, for example, is used as the sealing member 16.

[0024] The enclosed space 5 contains an electrode body 17, an electrolyte 18, and a moisture capture member 19 (see FIG. 2).

[0025] The electrode body 17 has a plurality of positive electrodes 20 and a plurality of negative electrodes 21 each formed in a sheet shape. The positive electrodes 20 and the negative electrodes 21 are arranged in a thickness direction, for example, in a front-to-rear direction, and are alternately stacked in the thickness direction with separators 22 interposed therebetween. Note that the electrode body 17 is only required to be provided with at least one positive electrode 20 and one negative electrode 21, and may have a so-called wound type configuration in which the stacked positive electrodes and negative electrodes are rolled.

[0026] A positive electrode current collector 23 connected to the positive electrode connection terminal 11a is attached to one end in the left-right direction of the positive electrode 20, and a negative electrode current collector 24 connected to the negative electrode connection terminal 11b is attached to the other end in the left-right direction of the negative electrode 21. Therefore, the positive electrode 20 and the positive electrode connection terminal 11a are electrically connected via the positive electrode current collector 23, and the negative electrode 21 and the negative electrode connection terminal 11b are electrically connected via the negative electrode current collector 24. The positive electrode current collector 23 and the negative electrode current collector 24 may be attached to the upper ends of the positive electrode 20 and the negative electrode 21, respectively (see FIG. 4).

[0027] The moisture capture member 19 has a base material 50 made of a resin material and a desiccant 60 dispersed therein. The volume fraction of the desiccant 60 in the moisture capture member 19 is set to 6.5 vol % or more and 39.3 vol % or less (details will be described later).

[0028] The moisture capture member 19 is formed, for example, in a ring-shaped sheet shape, and is in close contact with the upper surface of the electrode connection portion 12 with the shaft-shaped portion 13 inserted therethrough. With the connection terminal 11 attached to the cover 3, the sealing member 16 is pressed against the cover 3 and the moisture capture member 19 to seal the gap between the cover 3 and the connection terminal 11. The moisture capture member 19 is in a state where its outer periphery is in contact with the electrolyte 18.

[0029] The water capture member 19 is formed by laminating a water capture layer 19a having a desiccant 60 dispersed therein and an adhesion layer 19b that is adhered to the electrode connection portion 12 in the thickness direction (see FIG. 3). The adhesion layer 19b is provided as an adhesive layer having adhesive properties. However, the water capture member 19 may be a single layer consisting of the water capture layer 19a alone. Alternatively, the water capture layer 19a may function as an adhesive layer, or the water capture layer 19a may be adhered to the electrode connection portion 12 by an adhesive or the like.

[0030] A polyolefin resin, for example, polypropylene, is used as the base material 50. Therefore, since the base material 50 is formed from a hydrophobic material, the moisture that reaches the moisture capture member 19 tends to move toward the desiccant 60, and the moisture is easily adsorbed by the desiccant 60.

[0031] As the desiccant 60, a silica compound, for example, synthetic zeolite, is used. As the zeolite, for example, zeolite with a structure code LTA defined by the International Zeolite Association is used, and the pore size of the zeolite is, for example, 4 angstroms. By using the above-mentioned synthetic zeolite as the desiccant 60, moisture can be efficiently adsorbed. In particular, a material having a water-absorbing property that physically adsorbs moisture, such as zeolite, can release the adsorbed moisture to the atmosphere by heating, so there is no need to consider the decrease in the water-absorbing power caused by the desiccant 60 adsorbing moisture in the manufacturing process, and the good manufacturing condition of the water-capturing member 19 can be ensured.

[0032] However, the desiccant 60 dispersed in the moisture capture member 19 is not limited to synthetic zeolite, and any material having high moisture-absorbing properties that physically or chemically adsorbs moisture may be used. Specifically, for example, natural zeolite, silica gel, calcium chloride, calcium oxide, phosphorus pentoxide, strontium oxide, barium oxide, vanadium oxide, barium perchlorate, magnesium perchlorate, or a mixture thereof may be used. Note that the desiccant 60 may be a material that physically adsorbs moisture and a material that chemically adsorbs moisture.

[0033] In the nonaqueous electrolyte device 1 configured as above, a moisture capture member 19 is disposed in the enclosed space 5. Therefore, moisture brought into the enclosed space 5 is adsorbed by the desiccant 60 dispersed inside the moisture capture member 19, thereby reducing deterioration due to moisture and enabling the life of the nonaqueous electrolyte device 1 to be extended.

[0034] Furthermore, the moisture capture member 19 only needs to be placed in a predetermined position when the nonaqueous electrolyte device 1 is assembled, and there is no need to provide a dedicated step or treatment for suppressing moisture adsorption during the manufacturing process or storage process of the connection terminal 11 or the electrode body 17. Therefore, the moisture capture member 19 can be attached to the nonaqueous electrolyte device 1 without significantly increasing the workload during the manufacturing process of the nonaqueous electrolyte device 1.

[0035] Furthermore, the water capture member 19 is disposed between the sealing member 16 and the electrode connection portion 12, and the water capture member 19 is in contact with the sealing member 16. In the nonaqueous electrolyte device 1, even when the outer casing 4 is sealed, moisture in the air may infiltrate into the enclosed space 5 from the attachment portion of the connection terminal 11. As described above, by disposing the water capture member 19 between the sealing member 16 and the electrode connection portion 12, moisture that attempts to penetrate the water capture member 19 and infiltrate into the enclosed space 5 is adsorbed by the desiccant 60, so that the infiltration of moisture into the enclosed space 5 can be suppressed. In addition, since there is no need to newly provide a dedicated member for attaching the water capture member 19 in the enclosed space 5, it is possible to suppress an increase in manufacturing costs and improve manufacturability.

[0036] Although the above example shows that the water capture member 19 is arranged between the sealing member 16 and the electrode connection portion 12, the water capture member 19 may be arranged between the sealing member 16 and the cover 3, or the water capture member 19 may be configured to be arranged both between the sealing member 16 and the electrode connection portion 12 and between the sealing member 16 and the cover 3.

[0037] <Volume fraction of desiccant> Here, the volume fraction of the desiccant 60 in the water capture member 19 will be specifically described (see FIGS. 5 and 6).

[0038] First, if the diameter of a particle of the desiccant 60 is D, the volume V of the particle is expressed by the following formula (1).

[0039]

number

[0040] Furthermore, if the length of one side of a cubic region in the water capture member 19 containing one particle of the desiccant 60 is taken as a (see FIG. 5), the volume fraction Φ of the particle in the water capture member 19 can be expressed by the following formula (2). Note that the above-mentioned cubic region is shown as an example of a region (repeating unit) containing one particle, but the repeating unit is not limited to this and may have any configuration, such as a sphere with a diameter a.

[0041]

number

[0042] By transforming equation (2), we obtain equation (3).

number

[0043] Here, if the interval (distance) between the particles of the dispersed desiccant 60 is taken as the particle interval d (see FIG. 6), the particle interval d is expressed by the following formula (4).

number

[0044] By substituting equation (3) into equation (4), the particle spacing d can be expressed by the following equation (5).

number

[0045] Therefore, it can be seen that the particle spacing d can be expressed as the product of the particle diameter D and a coefficient based on the volume fraction Φ. If the coefficient based on the volume fraction Φ in equation (5) is taken as the spacing coefficient α, the spacing coefficient α can be expressed by the following equation (6).

number

[0046] Furthermore, by transforming equation (6), the volume fraction Φ can be expressed by the following equation (7).

number

[0047] Here, if the particle spacing d is larger than the particle diameter D, i.e., d>D, the area that cannot adsorb moisture (the area consisting of only the base material 50) becomes large, so that it takes a long time for the moisture to reach the desiccant 60, and there is a risk that a sufficient moisture absorbing speed of the moisture capture member 19 cannot be ensured. Therefore, the maximum value of the spacing coefficient α can be specified as 1.0.

[0048] From equation (7), the volume fraction Φ is minimum when α is maximum, so the lower limit of the volume fraction Φ can be obtained by substituting α = 1.0 into equation (7).

[0049]

number

[0050] Therefore, from formula (8), the volume fraction Φ of the desiccant 60 in the water capture member 19 can be specified to be 6.5 vol % or more.

[0051] On the other hand, the particles of the desiccant 60 dispersed in the base material 50 tend to aggregate as the particle spacing d becomes smaller. In particular, when the particle spacing d is smaller than one-tenth of the particle diameter D, the manufacturability of the water capture member 19 tends to decrease due to particle aggregation. Therefore, the minimum value of the spacing coefficient α can be set to 0.1.

[0052] From equation (7), the volume fraction Φ is maximum when α is minimum, so the upper limit of the volume fraction Φ can be obtained by substituting α = 0.1 into equation (7).

[0053]

number

[0054] Therefore, from formula (9), the volume fraction Φ of the desiccant 60 in the water capture member 19 can be specified to be 39.3 vol% or less. In order to ensure higher manufacturability of the water capture member 19, it is more preferable that the volume fraction Φ of the desiccant 60 in the water capture member 19 be 24.4 vol% or less.

[0055] As described above, the volume fraction Φ of the dispersed desiccant 60 in the water capture member 19 is set to 6.5 vol% or more and 39.3 vol% or less. This ensures a good dispersion state (particle spacing) of the desiccant 60 in the water capture member 19, and therefore ensures a high water capture speed while ensuring good manufacturability of the water capture member 19.

[0056] Furthermore, if weight fraction (wt%) is used to determine the proportion of desiccant dispersed in the water capture member, the specific gravity differs depending on the type of base material and desiccant used, and therefore it is necessary to determine the proportion each time the base material or desiccant is changed. However, as described above, by defining the proportion of desiccant dispersed in the water capture member by volume fraction, the proportion of dispersed desiccant does not depend on the type of base material or desiccant, and it is possible to use the same volume fraction even if, for example, the material of the base material is changed to a material with a different specific gravity.

[0057] <Non-aqueous electrolyte device according to the second embodiment> Next, a nonaqueous electrolyte device 1A according to a second embodiment will be described (see FIG. 7).

[0058] In each of the embodiments described below, only the parts that are different from the previously described embodiments will be described in detail, and the other parts will be given the same reference numerals as those given to similar parts in the previously described embodiments, and descriptions thereof will be omitted.

[0059] The nonaqueous electrolyte device 1A has a water capture member 19A. The water capture member 19A is, for example, in the form of a rectangular sheet, and is attached to the inner surface of the outer casing 4, for example, to the bottom surface portion 6, the peripheral surface portion 7, and the cover 3.

[0060] The water capture member 19A is formed by laminating, in the thickness direction, a water capture layer 19a in which a desiccant 60 is dispersed and an adhesion layer 19b that is adhered to the inner surface of the outer casing 4. The adhesion layer 19b is provided as an adhesive layer having adhesive properties. However, the water capture member 19A may be configured as a single layer in which the water capture layer 19a functions as an adhesive layer, or the water capture layer 19a may be adhered to the electrode connection portion 12 by an adhesive or the like.

[0061] As described above, by attaching the water capture member 19A to the inner surface of the outer casing 4, it becomes possible to attach a water capture member 19A with a large area without having to provide a new dedicated member for attaching the water capture member 19A in the enclosed space 5, and therefore it is possible to increase the upper limit of the amount of water capture by the water capture member 19A.

[0062] In the nonaqueous electrolyte device 1A, the water capture member 19A may be attached to at least one of the inner surfaces of the outer casing 4. However, in the nonaqueous electrolyte device 1A, the positive electrode 20 and the negative electrode 21 are made difficult to permeate with water, so that the water that adheres to the electrode body 17 and is brought into the enclosed space 5 mainly moves along the positive electrode 20 or the negative electrode 21 in the surface direction of the positive electrode 20 and the negative electrode 21 (direction perpendicular to the stacking direction). Furthermore, since the positive electrode current collector 23 and the negative electrode current collector 24 are attached to both the left and right ends of the electrode body 17, the internal water that adheres to the electrode body 17 mainly moves up and down. Therefore, by attaching the water capture member 19A to the inner surfaces of the outer casing 4, particularly the bottom surface portion 6 and the cover 3, the water capture member 19A is positioned at the destination of the internal water, so that the water capture effect of the water capture member 19A can be enhanced.

[0063] Furthermore, in the case where the nonaqueous electrolyte device 1A is configured so that the positive electrode current collector 23 and the negative electrode current collector 24 are attached to the upper end of the electrode body 17, the moisture adhering to the electrode body 17 moves not only vertically but also horizontally. Therefore, it is desirable to attach the moisture capture member 19A to the side portions 10, 10 of the peripheral portion 7 in addition to the bottom portion 6 and the cover 3.

[0064] Furthermore, by attaching the water capture member 19A to the front portion 8 and the rear portion 9, the water capture member 19A is positioned opposite the positive electrode 20 or the negative electrode 21, so that the internal moisture adhering to the outer surfaces in the stacking direction of the positive electrode 20 and the negative electrode 21 is easily adsorbed by the desiccant 60, thereby enhancing the water capture effect of the water capture member 19A.

[0065] Although the above example shows the use of a sheet-shaped water-capturing member, the shape of the water-capturing member is not limited to a sheet shape, and the water-capturing member may be formed into any shape, such as a plate shape, a rectangle shape, or a tablet shape, depending on the position where it is attached. However, forming the water-capturing member into a sheet shape makes it easy to manufacture and ensures high versatility. The nonaqueous electrolyte device 1, 1A may be configured such that a paste-like water-capturing member having a desiccant 60 dispersed therein is applied to each desired portion.

[0066] <Non-aqueous electrolyte device according to the third embodiment> Next, a nonaqueous electrolyte device 1B according to a third embodiment will be described (see FIGS. 8 to 10).

[0067] The nonaqueous electrolyte device 1B has a water capture member 19B. The water capture member 19B is formed in a sheet shape and attached to the electrode assembly 17 so as to cover the upper and lower ends of the electrode assembly 17 (see FIGS. 8 and 9).

[0068] As in the nonaqueous electrolyte device 1A, in the nonaqueous electrolyte device 1B, the internal moisture attached to the electrode assembly 17 mainly moves up and down. Therefore, by attaching the water capture member 19B to the electrode assembly 17 so as to cover the upper and lower ends (ends in a direction perpendicular to the stacking direction of the positive electrode 20 and the negative electrode 21), the water capture member 19B is positioned at the destination of the internal moisture, thereby ensuring a high water capture effect of the water capture member 19B.

[0069] In addition, in the nonaqueous electrolyte device 1B, when the positive electrode current collector 23 and the negative electrode current collector 24 are configured to be attached to the upper end of the electrode body 17, it is desirable that the water capture member 19B covers not only the upper and lower ends of the electrode body 17 but also the left and right ends (see FIG. 10).

[0070] <Non-aqueous electrolyte device according to the fourth embodiment> Next, a nonaqueous electrolyte device 1C according to a fourth embodiment will be described (see FIGS. 11 and 12).

[0071] The nonaqueous electrolyte device 1C has a water capture member 19C. The water capture member 19C is formed in a sheet shape and is wrapped around the electrode assembly 17 with the left-right direction as an axis (see FIG. 11). This causes the electrode assembly 17 to be wrapped in the water capture member 19C. Therefore, the moisture present in the electrode assembly 17 is easily adsorbed by the desiccant 60, and high water capture ability of the water capture member 19C for the electrode assembly 17 can be ensured.

[0072] The water capture member 19C may be wound around the electrode assembly 17 with the vertical axis as shown in FIG. 12. In this case, the water capture member 19C is wound around the electrode assembly 17 with the positive electrode current collector 23 and the negative electrode current collector 24 attached to the electrode assembly 17. This makes it easier for the desiccant 60 to adsorb the internal moisture adhering to the positive electrode current collector 23 and the negative electrode current collector 24 in addition to the electrode assembly 17, so that the water capture effect of the water capture member 19C can be further improved. Furthermore, a plurality of water capture members 19C may be wound around the electrode assembly 17 with the horizontal or vertical axis as the axis.

[0073] In addition, the nonaqueous electrolyte devices 1, 1A, 1B, and 1C described above are not limited to a configuration in which the water capture members 19, 19A, 19B, and 19C are attached respectively, and may be configured in which the water capture members 19, 19A, 19B, and 19C are attached in any combination.

[0074] <Non-aqueous electrolyte device according to the fifth embodiment> Next, a nonaqueous electrolyte device 1D according to a fifth embodiment will be described (see FIGS. 13 and 14).

[0075] The nonaqueous electrolyte device 1D has a bag-shaped laminate material (outer packaging material) 30 and a tab lead 31, a part of which is positioned inside the laminate material 30 (see FIG. 13).

[0076] The laminate material 30 has an outer periphery formed as a sealing portion 32, both left and right ends and a lower end closed, and is bag-shaped with an opening at the top. The upper end of the laminate material 30 is formed as an inlet portion 30a, and the inlet portion 30a is sealed with the required parts enclosed inside to form an airtight seal. The laminate material 30 has a three-layer structure, and an outer surface layer 30b and an inner surface layer 30c each made of a resin material are laminated on both sides of a metal layer 30d (see FIG. 14). For example, polyethylene terephthalate is used as the outer surface layer 30b, a polyolefin resin such as polypropylene or polyethylene is used as the inner surface layer 30c, and aluminum is used as the metal layer 30d.

[0077] Tab lead 31 is composed of lead terminal 33 and a pair of film portions 34 covering both sides of lead terminal 33 (see FIG. 13), and functions as a connection terminal. A portion of tab lead 31 is in close contact with sealing opening portion 30a, and an upper end portion protrudes from laminate material 30.

[0078] The lead terminal 33 has, for example, a terminal body made of a metal material and a resin coating covering the surface of the terminal body. For example, aluminum, copper, pure nickel, or stainless steel is used as the terminal body. For example, acrylic resin is used as the base resin of the resin coating. The lower end of the lead terminal 33 is formed as an electrode connection part 33a and is connected to the positive electrode 20 or the negative electrode 21. The upper end of the lead terminal 33 is formed as an external terminal part 33b exposed to the outside from the laminate material 30, and power is taken out from the nonaqueous electrolyte device 1 by connecting a terminal part (not shown) of an external device to the external terminal part 33b. The lead terminal 33 is connected to the electrode (positive electrode 20 or negative electrode 21) by ultrasonic welding, and the resin coating at the electrode connection part 33a is lost due to the load during ultrasonic welding, and the terminal body is brought into contact with the electrode, thereby ensuring the conduction between the lead terminal 33 and the electrode. Furthermore, the lead terminal 33 is connected to the terminal portion of the external device by, for example, ultrasonic welding, and the resin coating on the external terminal portion 33b is removed by the load during ultrasonic welding, and the terminal body comes into contact with the terminal portion, thereby ensuring electrical continuity between the lead terminal 33 and the external device. However, the connection between the lead terminal 33 and the external device can be performed by various methods other than ultrasonic welding, such as laser welding or screw fastening.

[0079] The film portion 34 covers both sides of the lead terminal 33 in the thickness direction with both left and right ends protruding from the lead terminal 33 at the intermediate portion between the electrode connection portion 33a and the external terminal portion 33b. The film portion 34 is formed of an acid-modified polyolefin resin that is difficult for moisture to permeate, such as polypropylene (acid-modified polypropylene). The film portion 34 may be configured as a single-layer resin film, or may be configured by laminating a plurality of resin films. The film portion 34 may contain additives such as a desiccant, a crosslinking agent, and an antioxidant.

[0080] In the nonaqueous electrolyte device 1 configured as described above, the sealing opening 30a of the laminate material 30 is thermocompression-bonded with the outer surfaces in the thickness direction of the film portion 34 in contact with the inner surface layer 30c of the laminate material 30. When the sealing opening 30a of the laminate material 30 is pressurized in a state in which the film portion 34 is melted by heating, the gap between the lead terminal 33 and the inner surface layer 30c is sealed and the laminate material 30 is sealed.

[0081] When the laminate material 30 is sealed, the internal space of the laminate material 30 is formed as an enclosed space 35 .

[0082] The electrode body 17, the electrolyte 18, and the water capture member 19D are enclosed in the enclosed space 35 (see FIGS. 13 and 14).

[0083] The water capture member 19D is formed, for example, in a frame shape, and is attached, for example, to the inner surface layer 30c of the laminate material 30. The shape of the water capture member 19D is not limited to a frame shape, and may be formed in any shape such as a sheet shape, a plate shape, or a tablet shape. The position where the water capture member 19D is attached is also not limited to the inner surface layer 30c of the laminate material 30, and the water capture member 19D may be attached to the electrode body 17 or the tab lead 31. Furthermore, as in each of the above-mentioned embodiments, the water capture member 19D may be configured to cover the end of the electrode body 17 in the direction perpendicular to the stacking direction of the positive electrode 20 and the negative electrode 21, or the water capture member 19D may be configured to be wrapped around the electrode body 17. However, by attaching the water capture member 19D near the sealing portion 32 into which moisture easily penetrates, the water capture member 19D can easily capture external moisture, and therefore a high water capture effect can be obtained for both internal moisture and external moisture. [Explanation of symbols]

[0084] 1, 1A, 1B, 1C, 1D Non-aqueous electrolyte devices 2 Case body 3 Cover 4. Outer casing (exterior body) 11 Connection terminal 17 Electrode body 18 Electrolyte 19, 19A, 19B, 19C, 19D Water capture members 20 positive electrode 21 Negative electrode 22 Separator 30 Laminate material (exterior body) 31 Tab lead (connection terminal) 50 Base material 60 Desiccant

Claims

1. A moisture capture member in which a desiccant is dispersed inside a base material formed of a resin material, The volume fraction of the desiccant is set to 6.5 vol % or more and 39.3 vol % or less. Water capture member.

2. The base material is formed into a sheet shape. The water capture member according to claim 1 .

3. A material that adsorbs moisture by physical adsorption is used as the desiccant. The water capture member according to claim 1 or 2.

4. A silica compound was used as the desiccant. The water capture member according to claim 3.

5. Zeolite or silica gel was used as the desiccant. The water capture member according to claim 4.

6. A polyolefin resin was used as the resin material. The water capture member according to claim 1 or 2.

7. an exterior body in which at least an electrode and an electrolytic solution or a solid electrolyte are enclosed; a connection terminal electrically connected to the electrode; a moisture capture member having a base material formed of a resin material and a desiccant dispersed therein; The volume fraction of the desiccant in the water capture member is set to 6.5 vol % or more and 39.3 vol % or less. Non-aqueous electrolyte devices.

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