Power storage device and method for manufacturing power storage device

Abstract

To provide a power storage device in which deformation and thermal stress occurring in a resin member for fixing a terminal member to a case member are suppressed, and to provide a method of manufacturing the power storage device.SOLUTION: In the power storage device 1 including the resin member 50 that fixes the terminal member 40 to the case member 25, the resin member includes the interposed portion 54 located between the case member and the terminal outward surface 44a of the terminal member, and includes the first resin portion 60, 160 formed of the first resin material 61 including the first resin 61a that is thermoplastic and electrically insulating and the first filler 61b, and the second resin portion 70, 170 formed of the second resin material 71 including the second resin 71a that is thermoplastic and electrically insulating and integrally molded with the case member and the terminal member and fixed to the case member and the terminal member. The interposed part has a first interposed part 64164 of the first resin component and a second interposed part 74174 of the second resin component, and an average second alignment direction H2av of the second filler in the second interposed part intersects with an average first alignment direction H1av of the first filler in the first interposed part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device in which a terminal member inserted into a through hole of a case member constituting a case is fixed to the periphery of the through hole of the case member via a resin member containing a fibrous filler, and to a method for manufacturing the electricity storage device. [Background technology]

[0002] A known energy storage device is a battery in which positive and negative terminal members are fixed via a resin member to a rectangular plate-shaped case lid member, which is a case member that constitutes a rectangular box-shaped case. Specifically, the positive and negative terminal members are inserted into insertion holes provided in the case lid member and extend from the inside to the outside of the case, and the resin member hermetically joins the terminal members to the case lid member while insulating them from the periphery of the through hole in the case lid member, thereby fixing the terminal members to the case lid member.

[0003] When manufacturing such a battery, a resin member may be insert-molded. That is, the resin member is insert-molded with the terminal member inserted into the insertion hole of the case lid member, and the terminal member is fixed to the case lid member via the resin member. Related prior art is, for example, Patent Document 1 (see Figures 2, 6, 7, etc. of Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-079172 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to improve the strength of the resin member or to bring the linear expansion coefficient of the resin material constituting the resin member closer to the linear expansion coefficient of the metal constituting the case member or terminal member, fibrous fillers such as glass fiber or carbon fiber may be added to the resin material.

[0006] However, during insert molding, fibrous fillers contained in molten resin move with the flow of the molten resin, tending to orient along the flow, i.e., with the longitudinal direction of the fillers parallel to the flow of the molten resin. This results in the resin component after molding being prone to have fillers oriented in specific directions in various locations. Furthermore, resin materials containing fibrous fillers exhibit anisotropy, meaning that the resin material's properties (e.g., linear expansion coefficient and strength) differ between the filler orientation direction parallel to the longitudinal direction of the fillers and the direction perpendicular to the filler orientation direction. Therefore, if a portion of the resin component contains oriented fillers, anisotropy of the properties occurs in that portion. For example, when an energy storage device is subjected to a thermal cycle test, the difference in thermal expansion between the resin component and the case or terminal component also becomes anisotropic. Depending on the relationship between the direction of stress in the resin component and the orientation direction, cracks may occur in the resin component near the interface between the resin component and the case or terminal component, or the cracks may cause defects such as seal failure.

[0007] The present invention has been made in consideration of the current situation, and provides an electricity storage device that suppresses deformation and thermal stress that occur in the resin member that fixes the terminal member to the case member, and a method for manufacturing this electricity storage device. [Means for solving the problem]

[0008] (1) One aspect of the present invention for solving the above problem is an electric storage device including a case member made of metal and having an insertion hole, a terminal member made of metal and inserted into the insertion hole of the case member, and a resin member that hermetically joins the case member and the terminal member while insulating them from each other and fixes the terminal member to the case member, wherein the resin member has an interposition portion located between a case inward surface of the case member and a terminal outward surface of the terminal member that faces the case inward surface, and the resin member is made of a first resin material that includes a thermoplastic and insulating first resin and a fibrous first filler. and a second resin portion made of a second resin material containing a thermoplastic, insulating second resin and a fibrous second filler, the second resin portion being integrally welded to the first resin portion and being integrally molded with the case member and the terminal member, and being fixed to the case member and the terminal member, wherein the intermediate portion has a first intermediate portion of the first resin portion contained in the intermediate portion, and a second intermediate portion of the second resin portion contained in the intermediate portion, and an average second orientation direction of the second filler in the second intermediate portion intersects with an average first orientation direction of the first filler in the first intermediate portion.

[0009] In the above-described electricity storage device, in the interposed portion of the resin member, the average second orientation direction of the second interposed portion intersects with the average first orientation direction of the first interposed portion. Therefore, due to the orientation of the second filler in the average second orientation direction, the anisotropy of the properties occurring in the second interposed portion of the interposed portion is alleviated at least in the portion where the first interposed portion is provided and in its vicinity, and deformation of the resin member and thermal stress caused by the difference in thermal expansion occurring between the interposed portion and the case member or the terminal member can be suppressed.

[0010] In this electricity storage device, it is sufficient that the average second alignment direction is not parallel to the average first alignment direction but intersects with it, but preferably the average second alignment direction is approximately perpendicular to the average first alignment direction, specifically at an angle of 70 to 110 degrees, more preferably 80 to 100 degrees, because this effectively reduces the anisotropy of the alignment direction of the filler in the interposed portion.

[0011] In the energy storage device described in (1), the first intervening portion of the first resin part is a plurality of first parallel pillar portions each extending in a columnar shape at intervals in the same first direction, and includes a plurality of first parallel pillar portions formed by the injected first resin material progressing in the first direction when molding the first resin part; and the second intervening portion of the second resin part is preferably formed by positioning the first intervening portion of the first resin part between the case inward surface of the case member and the terminal outward surface of the terminal member when molding the second resin part, and includes a plate-shaped portion formed by the injected second resin material progressing in a second direction parallel to the case inward surface and intersecting the first direction on the case inward surface side or the terminal outward surface side of the plurality of first parallel pillar portions of the first resin part.

[0012] (2) Still another aspect is a connector comprising: a case member made of metal and having an insertion hole; terminal members made of metal and inserted into the insertion hole of the case member; and a resin member that hermetically joins the case member and the terminal members while insulating them and fixing the terminal members to the case member, the resin member having an intervening portion located between a case inward surface of the case member and a terminal outward surface of the terminal members that faces the case inward surface, the resin member having a first resin portion made of a first resin material containing a thermoplastic and insulating first resin and a fibrous first filler, and a second resin portion made of a second resin material containing a thermoplastic and insulating second resin and a fibrous second filler, the second resin portion being integrally welded to the first resin portion and being integrally molded with the case member and the terminal members to be fixed to the case member and the terminal members, the intervening portion being a first resin portion made of a first resin material containing a thermoplastic and insulating first resin and a fibrous first filler. A method for manufacturing an electricity storage device having a first intermediate portion in a resin portion that is included in the intermediate portion, and a second intermediate portion in the second resin portion that is included in the intermediate portion, wherein an average second orientation direction of the second filler in the second intermediate portion intersects an average first orientation direction of the first filler in the first intermediate portion, the method comprising: a first molding process for molding the first resin portion; and a second molding process for molding the second resin portion by injecting the second resin material with the case member, the terminal member, and the first resin portion arranged in a mold to obtain the resin member, wherein the second molding process molds the second resin portion by intersecting the average flow direction of the second resin material flowing through the second intermediate portion with the average first orientation direction of the first intermediate portion in the first resin portion when the second resin material is injected and flows within the mold to form the second intermediate portion.

[0013] (3) In the method for manufacturing an electric storage device described in (2), the first molding step may be a method for manufacturing an electric storage device in which the first interposition portion is integrally molded on a terminal facing portion of the case inward surface of the case member that faces the terminal outward surface, or on the terminal outward surface of the terminal member, or on each of the terminal facing portion of the case member and the terminal outward surface of the terminal member.

[0014] In the method for manufacturing an electricity storage device according to (2) or (3), the first intervening portion of the first resin part is a plurality of first parallel pillar portions each extending in a pillar shape at intervals in the same first direction, and includes a plurality of first parallel pillar portions each formed by the first resin material being injected in the first direction when molding the first resin part; the second intervening portion of the second resin part is formed by arranging the first intervening portion of the first resin part between the case inward surface of the case member and the terminal outward surface of the terminal member when molding the second resin part; and the injected second resin material is injected into the first resin part so that the first intervening portion of the first resin part is positioned between the case inward surface side or the terminal outward surface side of the plurality of first parallel pillar portions of the first resin part and the terminal outward surface side of the first resin part when molding the second resin part. and the first molding step is preferably a method for manufacturing an electricity storage device in which the first resin material is advanced in the first direction in the first intervening portion when molding the first resin portion by injecting the first resin material to form the plurality of first parallel pillar portions, and the second molding step is preferably a method for manufacturing an electricity storage device in which the first intervening portion of the first resin material is positioned between the case inward surface of the case member and the terminal outward surface of the terminal member in the mold, and the second resin material is injected and advanced in the second direction on the case inward surface side or the terminal outward surface side of the plurality of first parallel pillar portions to form the plate-like portions. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a partial cross-sectional view taken along the battery height direction and the battery width direction of a battery according to an embodiment and first and second modified embodiments. [Figure 2] 5 is an enlarged cross-sectional view taken along the line BB in FIG. 4 showing a terminal portion of the case lid member according to the embodiment and modified embodiment 2. FIG. [Figure 3] 5 is an enlarged cross-sectional view taken along the line CC in FIG. 4 showing a terminal portion of the case lid member according to the embodiment and the first and second modified embodiments. FIG. [Figure 4] 10 is a view of the terminal portion of the case lid member as viewed from the inside in the embodiment and modified embodiments 1 and 2. FIG. [Figure 5]1 is a flowchart of a method for manufacturing a battery according to an embodiment and first and second modified embodiments. [Figure 6] 8 is an explanatory view of a cross section taken along line DD in FIG. 7, showing how the second resin material is injected in the second molding step in the battery manufacturing method according to the embodiment and the first and second modified embodiments. FIG. [Figure 7] 10 is an explanatory diagram showing the orientation direction of fillers in a first resin portion and a second resin portion in a resin member of a battery according to an embodiment and first and second modified embodiments. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] (Embodiment) A battery 1 (an example of an electricity storage device) according to an embodiment will be described below with reference to the drawings. FIG. 1 shows a partial cross-sectional view of the battery 1. FIGS. 2 to 4 show enlarged views of the terminal portion of the case lid member. In the following description, the battery height direction AH, battery width direction BH, and battery thickness direction CH of the battery 1 will be defined as the directions shown in FIGS. 1 to 4. The battery 1 is a rectangular, sealed lithium ion secondary battery that is installed in hybrid cars, plug-in hybrid cars, electric vehicles, drones, and the like. In addition to lithium ion secondary batteries, examples of "electricity storage devices" include secondary batteries such as sodium ion secondary batteries and calcium ion secondary batteries, and capacitors such as lithium ion capacitors.

[0017] This battery 1 is composed of a case 10, an electrode assembly 30 and an electrolyte 5 housed in the case 10, and positive and negative terminal members 40 fixed to the case 10 via resin members 50. Inside the case 10, the electrode assembly 30 is covered by a bag-shaped insulating holder 7 made of insulating film.

[0018] The case 10 is a rectangular box made of metal (aluminum in this embodiment), and is configured from a case body member 20 in the shape of a bottomed square cylinder with a rectangular opening 20c. The case body member 20 houses the electrode assembly 30 therein, and a rectangular plate-shaped case lid member 25 that closes the opening 20c of the case body member 20. In this embodiment, the case lid member 25 corresponds to the aforementioned "case member." The opening 20c of the case body member 20 and a peripheral edge 25f of the case lid member 25 are hermetically welded along the entire periphery. The case lid member 25 is provided with a safety valve 11 that ruptures and opens when the internal pressure of the case 10 exceeds a predetermined valve opening pressure. The case lid member 25 is also provided with a liquid inlet 25k, which is hermetically sealed with a disk-shaped sealing member 12 made of aluminum.

[0019] In addition to aluminum, duralumin, stainless steel, and the like can also be used as the metal forming the case 10 or the case lid member 25. Furthermore, the "case member" can also refer to the above-mentioned case lid member 25 as well as the bottomed cylindrical case main body member 20. In the case of a case consisting of a cylindrical case main body member and a pair of case lid members that seal the openings on both sides of the case main body member, examples of the case member include the case lid member and the case main body member.

[0020] The electrode assembly 30 is a rectangular parallelepiped laminate, consisting of multiple rectangular positive electrode plates 31 and multiple rectangular negative electrode plates 32 alternately stacked in the battery thickness direction CH with rectangular separators 33 made of porous resin films sandwiched between them. On one side BH1 of the electrode assembly 30 in the battery width direction BH, the current collecting foils of the positive electrode plates 31 overlap in the battery thickness direction CH to form a positive current collecting portion 30c. A positive electrode terminal member 40 is electrically connected to this positive current collecting portion 30c. On the other side BH2 of the electrode assembly 30 in the battery width direction BH, the current collecting foils of the negative electrode plates 32 overlap in the battery thickness direction CH to form a negative current collecting portion 30d. A negative electrode terminal member 40 is electrically connected to this negative current collecting portion 30d.

[0021] Rectangular insertion holes 25h are formed in the case lid member 25 near the ends of one side BH1 and the other side BH2 in the battery width direction BH. A positive electrode terminal member 40 made of aluminum is inserted into the insertion hole 25h on the one side BH1, and this terminal member 40 is fixed to the case lid member 25 while being insulated from the case lid member 25 via a resin member 50. A negative electrode terminal member 40 made of copper is inserted into the insertion hole 25h on the other side BH2, and this terminal member 40 is fixed to the case lid member 25 while being insulated from the case lid member 25 via the resin member 50. In addition to the aluminum and copper mentioned above, stainless steel and the like can also be used as the metal forming the terminal member 40.

[0022] The positive and negative terminal members 40 have similar configurations and will be described together below. The terminal member 40 is formed by welding an outer terminal member 40A and an inner terminal member 40B together. Of the terminal members 40, the outer terminal member 40A and the outer terminal portion 41 originating from it are rectangular plates that are slightly smaller than the insertion hole 25h and extend in the battery width direction BH and the battery thickness direction CH. They are located outside the case 10, specifically on the upper side AH1 above the case lid member 25. The terminal member 40 may be formed by joining multiple members as described above, or may be formed by bending a single member.

[0023] Meanwhile, the terminal inner portion 42 originating from the inner terminal member 40B is located mainly below the case lid member 25 on the side AH2, and penetrates the insertion hole 25h to be electrically connected to the terminal outer portion 41. The terminal inner portion 42 comprises a rectangular plate-shaped flange 44 that is long in the battery width direction BH, a bottomed square tubular protrusion 43 located in the center of the flange 44 and bulging from the flange 44 toward the upper side AH1, and a thin plate-shaped extension 45 that bends at a substantially right angle from an extension edge 44pp of the peripheral edge 44p of the flange 44 and extends toward the lower side AH2. The rectangular plate-shaped flange 44 has an inner flange 44I that extends toward the inner side BHI in the battery width direction BH and an outer flange 44O that extends toward the outer side BHO, and the aforementioned extension 45 extends from the extension edge 44pp of the outer flange 44O. The flange portion 44 is disposed parallel to the case lid member 25 via the resin member 50. Meanwhile, the protrusion 43 extending from the flange portion 44 to the upper side AH1 is inserted into the insertion hole 25h and protrudes above the case lid member 25 to the upper side AH1, and the rectangular plate-shaped top surface 43T is welded to the outer terminal member 40A, which serves as the terminal outer portion 41. Meanwhile, the extension portion 45 of the positive terminal member 40 is welded at its tip 45t to the positive current collector 30c of the electrode assembly 30. This provides electrical continuity between the positive current collector 30c and the positive terminal outer portion 41. Similarly, the extension portion 45 of the negative terminal member 40 is welded at its tip 45t to the negative current collector 30d of the electrode assembly 30, providing electrical continuity between the negative current collector 30d and the negative terminal outer portion 41.

[0024] Next, the resin member 50 (see also FIG. 7) will be described. The resin members 50 for the positive and negative electrodes are both airtightly joined to the case lid member 25 and the terminal member 40 while insulating the case lid member 25 from the terminal member 40, thereby fixing the terminal member 40 to the case lid member 25. The resin members 50 for the positive and negative electrodes have the same configuration, and will be described together below.

[0025] The resin member 50 is composed of a resin outer portion 51, a resin inner portion 53, and a protrusion surrounding portion 52 connecting them. Of these, the resin outer portion 51 surrounds the periphery of the terminal outer portion 41 and provides insulation between the terminal outer portion 41 and the case lid member 25. On the other hand, the resin inner portion 53 is located on a lower side AH2 than the inner surface 25b of the case lid member 25, surrounds the periphery of the flange portion 44 of the terminal inner portion 42, and provides insulation between the case lid member 25 and the flange portion 44. The protrusion surrounding portion 52 extends from the resin inner portion 53 and connects to the resin outer portion 51, and surrounds the outer peripheral surface 43p of the protrusion 43 of the terminal inner portion 42 on four sides around the terminal inner portion 42, providing insulation between the outer peripheral surface 43p and the inner peripheral surface 25p of the insertion hole 25h of the case lid member 25.

[0026] The resin inner portion 53 further comprises an intervening portion 54 and a flange surrounding portion 55. The intervening portion 54 is a generally rectangular plate whose dimension in the battery width direction BH is longer than its dimension in the battery thickness direction CH. The intervening portion 54 is located between the terminal-facing portion 25c of the inner surface 25b of the case lid member 25, which faces the flange 44 of the terminal member 40 toward the lower side AH2, and the outward surface 44a of the flange 44 of the terminal member 40, which faces the inner surface 25b toward the upper side AH1, thereby providing insulation between the case lid member 25 and the flange 44 of the terminal member 40. The flange surrounding portion 55 is a rectangular ring-shaped portion located around the intervening portion 54 and surrounds the flange 44 of the terminal member 40.

[0027] The resin member 50 is formed by two-stage molding, as described below. It consists of a first resin portion 60 and a second resin portion 70 that is integrally welded to the first resin portion 60 and is integrally molded and fixed to the case lid member 25 and the terminal member 40. The first resin portion 60 is made of a first resin material 61 containing a thermoplastic and insulating first resin 61a, a fibrous first filler 61b, and a thermoplastic first elastomer 61c. In this embodiment, the first resin 61a is PPS, and the first filler 61b is glass fiber approximately 10 μm in diameter and 300 μm in length. The first elastomer 61c is a polyurethane elastomer. The second resin portion 70 is made of a second resin material 71 containing a thermoplastic and insulating second resin 71a, a fibrous second filler 71b, and a thermoplastic second elastomer 71c. In this embodiment, the second resin 71a is PPS like the first resin 61a, the second filler 71b is glass fiber like the first filler 61b, and the second elastomer 71c is polyurethane elastomer like the first elastomer 61c. However, the second resin 71a of the second resin material 71 uses PPS whose softening point differs from that of the first resin 61a of the first resin material 61 by within ±20°C, specifically, whose softening point is approximately the same.

[0028] The first resin 61a and the second resin 71a are thermoplastic, insulating resins, and examples of resins that can be used include PEEK, PTFE, PFA, PE, PP, PET, and PVDF in addition to PPS. The first filler 61b and the second filler 71b are fibrous fillers, and in addition to glass fiber fillers, for example, carbon fiber fillers and ceramic fibers can also be used. Furthermore, as described above, the first resin material 61 and the second resin material 71 may contain a thermoplastic elastomer in addition to the above-mentioned thermoplastic resins and fibrous fillers.

[0029] The first resin material 61 and the second resin material 71 may be made of resin materials with different properties or softening points, or may be made of the same resin material. When resin materials with different softening points are used, the difference in softening points should be within ±20°C, and the first resin material 61 should preferably have a softening point equal to or higher than that of the second resin 71a. When the second resin material 71 is injected to form the second resin portion 70, the first resin portion 60 is less likely to melt and is therefore more likely to maintain its shape. Furthermore, when the first filler 61b and the second filler 71b are made of different resin materials, the filler compounding ratios may be different.

[0030] The intervening portion 54 of the resin inner portion 53 of the resin member 50 has a first intervening portion 64 included in the intervening portion 54 of the first resin portion 60 that constitutes part of the resin member 50, and a second intervening portion 74 included in the intervening portion 54 of the second resin portion 70. That is, the intervening portion 54 is composed of the first intervening portion 64 made of the first resin material 61 and the second intervening portion 74 made of the second resin material 71. In this embodiment, the entire first resin portion 60 is included in the intervening portion 54, forming two first intervening portions 64. Furthermore, the flange portion surrounding portion 55 of the resin inner portion 53 of the resin member 50 is entirely composed of the flange portion surrounding portion 77 of the second resin portion 70. Similarly, the protrusion surrounding portion 52 and the resin outer portion 51 of the resin member 50 are entirely composed of the protrusion surrounding portion 78 and the resin outer portion 79 of the second resin portion 70.

[0031] The two first intermediate portions 64 have the same shape and are composed of a plurality of (three in this embodiment) first parallel pillar portions 65 extending in a columnar shape in the same first direction PH1 (which coincides with the battery thickness direction CH when assembled to the battery 1) at an interval SP, and a connecting portion 66 connecting the base ends 65b of the first intermediate portions 65 (see FIGS. 4 and 7). In this embodiment, the first intermediate portions 64 are integrally and closely attached to the case lid member 25 at the terminal-opposing portion 25c of the inner surface 25b. The first intermediate portions 64 are molded such that, when the first intermediate portions 64 (first resin portion 60) are molded as described below, the injected first resin material 61 travels through the connecting portion 66 and then travels through each of the first parallel pillar portions 65 in the first direction PH1. For this reason, the orientation direction of the first filler 61b is approximately oriented in the first direction PH1 in each of the first parallel columnar portions 65 of the first intermediate portion 64. As a result, in this embodiment, the average first orientation direction H1av, which is the average of the orientation directions of the first filler 61b in the first intermediate portion 64, also approximately oriented in the first direction PH1.

[0032] On the other hand, the second intervening portion 74 of the second resin portion 70 forms the portion of the intervening portion 54 excluding the first intervening portion 64, and is integrally and closely attached to the terminal-facing portion 25c of the case lid member 25 and to the flange portion 44 of the terminal member 40. This second intervening portion 74 includes inter-column portions 75 located between the first parallel column portions 65, as well as a plate-like portion 76 located on the outward surface side IH2 (which corresponds to the lower side AH2 in this embodiment) of the first parallel column portions 65 and inter-column portions 75.

[0033] Prior to molding the second resin portion 70 as described below, the first intervening portion 74 is disposed between the terminal-facing portion 25c of the case lid member 25 and the outward surface 44a of the flange portion 44 of the terminal member 40, with the first direction PH1 aligned with the battery thickness direction CH. The injected second resin material 71 then travels below the first parallel column portions 65 of the first resin portion 60 in a second direction PH2 that is parallel to the inner surface 25b and perpendicular to the first direction PH1 (in this embodiment, this direction coincides with the battery width direction BH that is perpendicular to the battery thickness direction CH), forming the inter-column portion 75 and the plate-like portion 76. Therefore, in the plate-like portion 76 of the second intervening portion 74, the orientation direction of the second filler 71b is substantially aligned with the second direction PH2. As a result, in this embodiment, the average second orientation direction H2av, which is the average of the orientation directions of the second filler 71b in the second intervening portion 74, also faces roughly in the second direction PH2. Note that it is thought that the molten second resin material 71 that has advanced while forming the plate-like portion 76 reaches the inter-column portion 75 of the second intervening portion 74 in a wraparound manner, and the orientation direction of the second filler 71b in the inter-column portion 75 is thought to have little bias in a particular direction and little effect on the value of the average second orientation direction H2av.

[0034] That is, in the intermediate portion 54, the average second alignment direction H2av of the second filler 71b in the second intermediate portion 74 intersects with the average first alignment direction H1av of the first filler 61b in the first intermediate portion 64. Specifically, in this embodiment, the average second alignment direction H2av is approximately perpendicular to the average first alignment direction H1av, that is, intersects with it at an angle within a range of 70 to 110 degrees. Furthermore, the intersects with it at an angle within a range of 80 to 100 degrees. More specifically, the average second alignment direction H2av intersects with the average first alignment direction H1av at an angle of 83 degrees. Therefore, by orienting the second filler 71b in the average second orientation direction H2av, the anisotropy of the characteristics occurring in the second intervening portion 74 of the intervening portion 54 is alleviated at least in the portion where the first intervening portion 64 is provided and in its vicinity, and deformation and thermal stress of the resin member 50 caused by the difference in thermal expansion occurring between this intervening portion 54 and the case lid member 25 or the terminal member 40 can be suppressed.

[0035] In particular, in the battery 1 of this embodiment, the first interposition portion 64 includes a plurality of first parallel columnar portions 65 formed by the first resin material 61 advancing in a first direction PH1 (battery thickness direction CH). Meanwhile, the second interposition portion 74 of the second resin portion 70 includes a plate-like portion 76 formed by the second resin material 71 advancing in a second direction PH2 (battery width direction BH). As described above, the orientation direction of the first filler 61b in the plurality of first parallel columnar portions 65 is approximately the first direction PH1. Meanwhile, the orientation direction of the second filler 71b in the plate-like portion 76 is approximately the second direction PH2, which intersects with and is generally perpendicular to the first direction PH1. Therefore, in this battery 1, the plurality of first parallel columnar portions 65 in the interposition portion 54 of the resin member 50 effectively alleviate the anisotropy of the orientation direction of the second filler 71b in the plate-like portion 76, thereby suppressing deformation of the resin member 50 and the occurrence of thermal stress.

[0036] The average first orientation direction H1av of the first filler 61b in the first intermediate portion 64 of the resin member 50 and the average second orientation direction H2av of the second filler 71b in the second intermediate portion 74 can be obtained, for example, as follows: The resin member 50, from which the case lid member 25 and the terminal member 40 have been removed by dissolution or the like, is imaged using an X-ray micro CT (in this embodiment, a TDM3000H-FP manufactured by Yamato Chemical Co., Ltd., not shown), to reconstruct a three-dimensional image of the resin member 50. At the same time, the resin member 50 is virtually divided into a large number of tiny rectangular parallelepiped portions (in this embodiment, 300 μm wide × 200 μm thick × 100 μm high, not shown) using three mutually orthogonal division cross sections, i.e., three division planes perpendicular to the X-axis, Y-axis, and Z-axis, respectively, and the average orientation direction of the filler in each rectangular parallelepiped portion is obtained. Next, each rectangular parallelepiped portion included in the interposition portion 54 is classified into a rectangular parallelepiped portion belonging to the first interposition portion 64 and a rectangular parallelepiped portion belonging to the second interposition portion 74. After that, the average of the average alignment directions of each rectangular parallelepiped portion belonging to the first interposition portion 64 is calculated and designated as the average first alignment direction H1av. In addition, the average of the average alignment directions of each rectangular parallelepiped portion belonging to the second interposition portion 74 is calculated and designated as the average second alignment direction H2av.

[0037] When performing tomographic imaging of the resin member 50 with the X-ray micro CT, the X axis of the device was aligned with the battery width direction BH of the resin member 50, the Y axis of the device was aligned with the battery thickness direction CH of the resin member 50, and the Z axis of the device was aligned with the battery height direction AH of the resin member 50, and then tomographic imaging of the resin member 50 was performed. In addition, the average orientation direction of the filler in each rectangular parallelepiped portion constituting the resin member 50 was obtained using software provided with the X-ray micro CT.

[0038] Next, a method for manufacturing the battery 1 will be described (see FIGS. 5 to 7). A case lid member 25 and a pair of positive and negative terminal members 40 are prepared. The positive and negative terminal members 40 are formed by forming an inner terminal member 40B having a protruding portion 43 bulging from a flange portion 44 and an extending portion 45 bent relative to the flange portion 44, and a flat outer terminal member 40A, which are welded together.

[0039] 5, a pair of first resin portions 60 (first intervening portions 64) are integrally molded using a first resin material 61 on the terminal facing portions 25c near the pair of insertion holes 25h on the inner surface 25b of the case lid member 25. Specifically, a mold (not shown) is used to injection-molde the pair of first resin portions 60 integrally with the case lid member 25. At this time, the molten first resin material 61 is injected from a first gate portion 66G at the center of the connecting portion 66, and is caused to pass through the connecting portion 66 and advance in a first direction PH1 from the base end portion 65b toward the tip end portion 65s of each of the plurality of (three in this embodiment) first parallel pillar portions 65, thereby molding the first parallel pillar portions 65. For this reason, as described above, the orientation direction of the first fillers 61b is approximately oriented in the first direction PH1 in each of the first parallel columnar portions 65 of the first intermediate portion 64. As a result, in this embodiment, the average first orientation direction H1av in the first intermediate portion 64 including the connecting portion 66 is also approximately oriented in the first direction PH1.

[0040] Next, in the second molding process S2, the outer terminal portions 41 of the positive and negative terminal members 40 are inserted into the pair of insertion holes 25h of the case lid member 25 from the side of the inner surface 25b (the lower side AH2) so as to protrude above the outer surface 25a to the upper side AH1. After that, a pair of second resin portions 70 are injection molded onto the assembled case lid member 25 and the pair of positive and negative terminal members 40 to form the resin member 50. As a result, the positive and negative terminal members 40 are fixed integrally to the case lid member 25 by the resin member 50 airtightly joined thereto while insulating the case lid member 25 from the positive and negative terminal members 40.

[0041] This second molding step S2 is performed using a mold DE having an upper mold DA and a lower mold DB (see FIG. 6). The upper mold DA abuts against the outer surface 25a of the case lid member 25 and the outer surface 41a of the terminal outer portion 41 of the terminal member 40. The lower mold DB abuts against the inner surface 25b of the case lid member 25 and the flange portion 44 of the terminal inner portion 42 of the terminal member 40. With the case lid member 25, the pair of terminal members 40, and the first resin portion 60 arranged in the mold DE, a molten second resin material 71 is injected from the second gate DG through the second gate portion 77G to mold the pair of second resin portions 70 and obtain the pair of resin members 50. As can be easily understood from FIGS. 4 and 7, within the mold DE, the first direction PH1 in which the first parallel column portion 65 of the first resin portion 60 extends coincides with the direction perpendicular to the paper surface in FIG. 6, i.e., the battery thickness direction CH.

[0042] In the second molding step S2, the mold DE, the case lid member 25, the pair of first resin portions 60, and the pair of terminal members 40 form a pair of cavities DC for molding the pair of second resin portions 70. As described above, in this embodiment, the first resin portions 60 are molded integrally with the case lid member 25 and are located on the upper side AH1 in FIG. 6. Therefore, the molten second resin material 71 injected from the second gate DG into the cavity DC flows generally in the direction of flow F2 indicated by the arrows in FIGS. 6 and 7 to mold the second resin portions 70. That is, between the terminal-facing portion 25c of the inner surface 25b of the case lid member 25 and the outward surface 44a of the flange portion 44 of the terminal member 40, the molten second resin material 71 flows between the first resin portion 60 and the flange portion 44 in the second direction PH2, generally from right to left in FIG. 6, along the outward surface 44a of the flange portion 44, to form a plate-shaped portion 76. That is, it flows toward the inner side BHI in the battery width direction BH, to form the plate-shaped portion 76. Note that, between the multiple first parallel column portions 65, the molten second resin material 71 flows toward the upper side AH1, wrapping around the first parallel column portions 65, to form inter-column portions 75 that protrude from the plate-shaped portion 76 toward the upper side AH1.

[0043] For this reason, as described above, in the plate-like portion 76 along the outward surface 44a of the second intermediate portion 74 of the second resin portion 70, the orientation direction of the second filler 71b is approximately in the second direction PH2 (battery width direction BH) and is approximately perpendicular to the first direction PH1 (battery thickness direction CH), which is the orientation direction of the second filler 71b in the first parallel column portions 65. As a result, in this embodiment, the average second orientation direction H2av in the second intermediate portion 74 including the inter-column portions 75 also is approximately in the second direction PH2 (battery width direction BH) and is also approximately perpendicular to the average first orientation direction H1av of the first intermediate portion 64 described above.

[0044] In the subsequent electrode assembly connecting step S3 (see FIG. 5), the extending portion 45 of the positive electrode terminal member 40 is ultrasonically welded to the positive electrode current collecting portion 30c of the electrode assembly 30, which has been prepared separately. Also, the extending portion 45 of the negative electrode terminal member 40 is ultrasonically welded to the negative electrode current collecting portion 30d of the electrode assembly 30. Thereafter, the electrode assembly 30 is packaged in an insulating holder 7 in the form of a bag with a bottom.

[0045] Next, in the electrode assembly containing / case forming process S4, the electrode assembly 30 covered with the insulating holder 7 described above is inserted into a separately prepared case body member 20 in the shape of a rectangular box with a bottom, and the opening 20c of the case body member 20 is closed with a case lid member 25. The opening 20c of the case body member 20 and the peripheral edge 25f of the case lid member 25 are then laser-welded airtightly along the entire periphery to form a case 10 containing the electrode assembly 30 inside.

[0046] In the liquid injection and sealing step S5, the electrolyte 5 is injected into the case 10 through the liquid injection hole 25k, and the electrolyte 5 is impregnated into the electrode body 30. Thereafter, the liquid injection hole 25k is covered from the outside with a sealing member 12, and the sealing member 12 is laser-welded to the case lid member 25 in an airtight manner.

[0047] In the initial charging and aging step S6, a charging device (not shown) is connected to the battery 1 to initially charge the battery 1. After that, the initially charged battery 1 is left at a high temperature for a predetermined time to age the battery 1. In this way, the battery 1 is completed.

[0048] In the manufacturing method of the battery 1 described above, the second resin material 71 is injected in the second molding step S2 to form the second resin portion 70. When forming the second intermediate portion 74 of the second resin portion 70, the average flow direction F2av of the flow F2 of the injected second resin material 71 flowing through the second intermediate portion 74 is made to intersect with the average first alignment direction H1av in the first resin portion 60 (first intermediate portion 64). This makes it possible to easily form the resin member 50 in which the average second alignment direction H2av in the second intermediate portion 74 intersects with the average first alignment direction H1av in the first intermediate portion 64.

[0049] Moreover, in this manufacturing method, the first resin part 60 is molded not as an independent part, but integrally with the terminal-facing part 25c on the inner surface 25b of the case lid member 25. Therefore, the first resin part 60 will not move when the second resin material 71 is injected in the second molding step S2. Furthermore, there is no need to set the first resin part 60 in the mold DE separately from the case lid member 25 and the terminal members 40. By positioning the case lid member 25 and the terminal members 40, the first resin part 60 can be easily and appropriately positioned in the mold DE. In this state, the second resin part 70 can be molded to obtain the resin member 50.

[0050] In the above-described manufacturing method, in the first lid-side molding step S1, the injected first resin material 61 is advanced in the first direction PH1 to form multiple first parallel column portions 65. Then, in the second molding step S2, the first intervening portion 64 of the first resin portion 60 is positioned between the terminal-facing portion 25c of the case lid member 25 and the outward surface 44a of the flange portion 44 of the terminal member 40 in the mold DE, and then the second resin material 71 is injected to form the second resin portion 70. Therefore, in the intervening portion 54 of the resin member 50, the multiple first parallel column portions 65 effectively mitigate the anisotropy of the orientation direction of the second filler 71b in the plate-like portion 76, thereby facilitating the manufacture of a battery 1 that can suppress deformation of the resin member 50 and the occurrence of thermal stress.

[0051] (Variations 1 and 2) In the above-described embodiment, as shown by the solid line in Fig. 2, the first intermediate portion 64 of the first resin portion 60 is provided integrally with the terminal-facing portion 25c on the inner surface 25b of the case lid member 25. However, as shown by the dashed line in Fig. 2, a first intermediate portion 164 of the first resin portion 160 having the same shape as the first intermediate portion 64 of the embodiment is provided integrally with the outward surface 44a of the flange portion 44 of the terminal member 40. Accordingly, the second intermediate portion 174 included in the intermediate portion 54 of the second resin portion 170 constituting the resin member 50 may be configured with a plate-like portion 176 located along the inner surface 25b of the case lid member 25 on the inner surface side IH1 (which corresponds to the upper side AH1 in this embodiment) of the first intermediate portion 164 (the first parallel pillar portions 165 and the connecting portion 166), and an inter-pillar portion 175 extending from the plate-like portion 176 to the outward surface side IH2 (the lower side AH2) toward between the first parallel pillar portions 165 (Modified Embodiment 1). Note that the first intermediate portion 164 also has three first parallel pillar portions 165 extending in the first direction PH1.

[0052] Furthermore, the first intervening portion 64 of the first resin portion 60 is provided integrally with the terminal-facing portion 25c of the inner surface 25b of the case lid member 25, and the first intervening portion 164 of the first resin portion 160, shown by a dashed line in Fig. 2, is provided integrally with the outward surface 44a of the flange portion 44 of the terminal member 40. Accordingly, the second intervening portion 274 included in the intervening portion 54 of the second resin portion 270 constituting the resin member 50 may be configured with a plate-like portion 276 located between the two first intervening portions 64, 164, an inter-column portion 75 extending from this plate-like portion 276 to the upper side AH1 toward between the first parallel column portions 65, and an inter-column portion 175 extending to the lower side AH2 toward between the first parallel column portions 165 (variant 2).

[0053] In the first modified embodiment, instead of the first lid-side molding step S1, a first intermediate portion 164 is provided on each of the outward surfaces 44a of the flange portions 44 of the pair of terminal members 40 in a first terminal-side molding step S11 shown by dashed lines in Fig. 5. In the second modified embodiment, in addition to providing the first intermediate portion 64 integrally with the terminal-facing portion 25c on the inner surface 25b of the case lid member 25 in the first lid-side molding step S1, the first intermediate portion 164 is also provided on each of the outward surfaces 44a in the first terminal-side molding step S11.

[0054] While the present invention has been described above in accordance with the embodiment and modified embodiments 1 and 2, it goes without saying that the present invention is not limited to the embodiment, etc., and can be appropriately modified and applied without departing from the spirit of the present invention. In the embodiment, etc., as can be seen from Figures 2, 4, and 7, the first intermediate portion 64 occupies the entire first resin portion 60. However, the first resin portion may include a portion other than the first intermediate portion.

[0055] Furthermore, in the embodiment and modified embodiments 1 and 2, the first intermediate portion 64 is previously attached integrally to the case lid member 25, or the first intermediate portion 164 is previously molded integrally with the flange portion 44 of the terminal member 40. However, instead of previously molding the first intermediate portion of the first resin portion integrally with the case lid member or the terminal member, the first resin portion including the first intermediate portion may be formed as an independent member, and the first intermediate portion of this independent first resin portion may be disposed between the case inward surface of the case member and the terminal outward surface of the terminal member, and the resin member may be molded by injecting the second resin material. [Explanation of symbols]

[0056] 1. Battery (energy storage device) 10 cases 25 Case cover member (case member) 25h insertion hole 25b (of the case cover member) inner surface (face facing inward of the case) 25c Terminal opposing part 40 Terminal member 50 Resin parts 51 Resin outer part 52 Surrounding area of ​​protrusion 53 Resin inner part 54 Interposition part 55 Brim periphery 60,160 First resin part 61 First resin material 61a First Resin 61b First Filler H1av Average first orientation direction 64,164 1st intervening part 65,165 1st parallel column part sp spacing 65b Proximal end 65s tip 66,166 Connecting part 66G First Gate 70,170,270 Second resin part 71 Second resin material F2 (molten second resin material) flow F2av Mean flow direction 71a 2nd resin 71b Second Filler H2av Average second orientation direction 74,174,274 Second intervention part 75,175 Hashirama section 76,176,276 Plate-shaped part 77 Around the flange 78 Surrounding area of ​​protrusion 79 Resin outer part PH1 1st direction PH2 2nd direction IH1 Inner surface side (side facing inward of the case) IH2 Outward facing side (terminal outward facing side) DE mold S1 Lid side 1st forming process (1st forming process) S11 Terminal side 1st molding process (1st molding process) S2 2nd molding process

Claims

1. a case member made of metal and having an insertion hole; a terminal member made of metal and inserted into the insertion hole of the case member; and a resin member that hermetically joins the case member and the terminal member while insulating them from each other and fixes the terminal member to the case member. An electricity storage device, The resin member is an interposition portion located between the case inward surface of the case member and the terminal outward surface of the terminal member, the terminal outward surface facing the case inward surface; The resin member is a first resin portion made of a first resin material including a thermoplastic and insulating first resin and a fibrous first filler; a second resin portion made of a second resin material containing a thermoplastic and insulating second resin and a fibrous second filler, the second resin portion being integrally welded to the first resin portion, and being integrally molded with the case member and the terminal members to be fixed to the case member and the terminal members; The intervening portion is the first resin portion includes a first intermediate portion that is included in the intermediate portion, and the second resin portion includes a second intermediate portion that is included in the intermediate portion, an average second orientation direction of the second filler in the second intermediate portion intersects with an average first orientation direction of the first filler in the first intermediate portion; Energy storage device.

2. a case member made of metal and having an insertion hole; a terminal member made of metal and inserted into the insertion hole of the case member; and a resin member that hermetically joins the case member and the terminal members while insulating them from each other and fixes the terminal members to the case member, The resin member is an interposition portion located between the case inward surface of the case member and the terminal outward surface of the terminal member, the terminal outward surface facing the case; The resin member is a first resin portion made of a first resin material including a thermoplastic and insulating first resin and a fibrous first filler; a second resin portion made of a second resin material containing a thermoplastic and insulating second resin and a fibrous second filler, the second resin portion being integrally welded to the first resin portion, and being integrally molded with the case member and the terminal members to be fixed to the case member and the terminal members; The intervening portion is the first resin portion includes a first intermediate portion that is included in the intermediate portion, and the second resin portion includes a second intermediate portion that is included in the intermediate portion, an average second orientation direction of the second filler in the second intermediate portion intersects with an average first orientation direction of the first filler in the first intermediate portion; A method for manufacturing an electricity storage device, comprising: a first molding step of molding the first resin portion; a second molding step of injecting the second resin material into a mold to mold the second resin portion while the case member, the terminal member, and the first resin portion are disposed in the mold, thereby obtaining the resin member; The second molding step includes: When the second resin material is injected and flows within the mold to form the second intervening portion, an average flow direction of the second resin material flowing through the second intervening portion is made to intersect with the average first orientation direction in the first intervening portion of the first resin portion, thereby molding the second resin portion. A method for manufacturing an electricity storage device.

3. A method for manufacturing the electricity storage device according to claim 2, The first molding step includes: The first intermediate portion is integrally formed on a terminal facing portion of the case inward surface of the case member that faces the terminal outward surface, or on the terminal outward surface of the terminal member, or on each of the terminal facing portion of the case member and the terminal outward surface of the terminal member. A method for manufacturing an electricity storage device.

Images