Power storage device and method for manufacturing power storage device

Abstract

To provide a power storage device or the like having less anisotropy in characteristics (such as linear expansion coefficient and strength) of a resin member for fixing a terminal member to a case member.SOLUTION: A power storage device 1 includes: a case member 25; a terminal member 40; and a resin member 50 that insulates them from each other and is airtightly bonded to them. The resin member 50 includes a thermoplastic main resin 56 and a fibrous filler 58. The resin member 50 has a resin inner side part 52 and a resin outer side part 51. An uneven part 52w is provided on at least one of a resin inner side surface 52b facing an inner side EH and a resin bonding surface 52a facing an outer side DH of the resin inner side portion 52. The orientation of a filler 58 included in the resin inner side part 52 is disturbed by forming the uneven part 52w.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device in which terminal members are fixed to a case member constituting a case via a resin member containing a fibrous filler, and to a method for manufacturing the electricity storage device. [Background technology]

[0002] A known power 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 (case member) that forms 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 case lid member and the terminal members while insulating them from each other, thereby fixing the terminal members to the case lid member. 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]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-079172 Summary of the Invention [Problem to be solved by the invention]

[0004] 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. However, during insert molding, the fibrous filler particles contained in the molten resin tend to be oriented along the flow of the molten resin (i.e., the filler tends to be oriented so that its longitudinal direction is parallel to the flow of the molten resin), and therefore the filler also tends to be oriented within the resin component after molding. Filler orientation within the resin component is undesirable because it causes anisotropy in the properties of the resin component (e.g., linear expansion coefficient and strength) between the direction along the fibrous filler orientation and the direction perpendicular to the filler orientation. For example, when batteries are subjected to thermal cycling tests, it has been found that cracks (seal breakdown) can occur between the resin component and the case or terminal component due to the relationship between the direction of stress generated between the resin component and the case or terminal component and the orientation direction.

[0005] The present invention has been made in consideration of the current situation, and provides an electricity storage device in which the properties (linear expansion coefficient, strength, etc.) of the resin member that fixes the terminal member to the case member have little anisotropy, and a method for manufacturing the electricity storage device. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problem is an electricity storage device comprising: a case member including an insertion hole; a terminal member 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 fixing the terminal member to the case member, the resin member being insert-molded from a resin material including a thermoplastic main resin and a fibrous filler, the resin member having an inner resin portion located inside the case member and an outer resin portion extending from the inner resin portion through the insertion hole to the outside of the case member, the inner resin portion having an uneven portion on at least one of the inner resin surface facing inward and the resin joining surface facing outward and joining to the case member, and the molding of this uneven portion disrupts the orientation of the filler contained in the inner resin portion.

[0007] In the above-described electricity storage device, an uneven portion is provided on at least one of the resin inner surface and the resin joint surface of the resin member in the resin inner portion. The uneven portion causes the orientation of the filler contained in the resin inner portion to become disordered. Therefore, the orientation of the filler in the resin inner portion is more disordered than when the uneven portion is not provided. Specifically, the degree of filler orientation in each region of the resin inner portion (the percentage of the filler contained in each region that is oriented in a specific direction) is lower (the amount of filler oriented in a specific direction is reduced in each region of the resin inner portion). Furthermore, the filler does not have the same orientation direction in neighboring regions of the resin inner portion. A slight change in the position of a region changes the orientation direction of the filler. Therefore, in this electricity storage device, the resin member has less anisotropy in its properties (such as linear expansion coefficient and strength) than when the uneven portion is not provided.

[0008] Examples of the "electricity storage device" include secondary batteries such as lithium ion secondary batteries, sodium ion secondary batteries, and calcium ion secondary batteries, and capacitors such as lithium ion capacitors. The "main resin" refers to the resin material that makes up the largest weight percentage of the resin materials that make up the resin material. Examples of thermoplastic resins that can be used as the main resin include polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polytetrafluoroethylene (PTFE), and perfluoroalkoxyalkane (PFA). Examples of "fibrous fillers" include glass fibers and carbon fibers. The resin material may also contain materials other than the thermoplastic main resin and fibrous filler described above, such as a thermoplastic elastomer.

[0009] (2) In the electricity storage device according to (1), the plurality of convex portions and concave portions constituting the concave-convex portion may be arranged in a staggered pattern.

[0010] By arranging the numerous convex and concave portions that make up the uneven portion in a staggered pattern, the orientation of the filler contained in the resin inner portion is further disordered as the uneven portion is formed. Therefore, in this electricity storage device, the properties of the resin member in particular are less anisotropic.

[0011] (3) Still another aspect is a method for manufacturing an electricity storage device, comprising: a case member including an insertion hole; a terminal member 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 fixing the terminal member to the case member, the resin member being made of a resin material including a thermoplastic main resin and a fibrous filler and being insert-molded, the resin member having a resin inner portion located inside the case member and a resin outer portion extending from the resin inner portion through the insertion hole to the outside of the case member, the resin inner portion having an uneven portion on at least one of a resin inner surface facing the inside and a resin joint surface facing the outside and joined to the case member, the uneven portion being formed to disrupt the orientation of the filler contained in the resin inner portion, the insert molding process includes a cavity formation process of forming a cavity for molding the resin member using the resin material with a molding die, the case member, and the terminal member inserted therein; and an injection molding process of injecting molten resin of the resin material into the cavity, filling the cavity with the molten resin, and molding the resin member, wherein the cavity has an outer portion molding cavity for molding the resin outer portion, and an inner portion molding cavity for molding the resin inner portion, and the inner portion molding surface forming the inner portion molding cavity has an uneven molding portion for molding the uneven portion, and the injection molding process is a manufacturing method for an electricity storage device in which the uneven molding portion is used to disrupt the flow of the molten resin and disrupt the orientation of the filler contained in the molten resin while molding the resin inner portion having the uneven portion.

[0012] In the manufacturing method of the above-described electricity storage device, in the insert molding process, the uneven molding portion provided on the inner molding surface that forms the inner molding cavity disrupts the flow of the molten resin and disrupts the orientation of the filler contained in the molten resin. Therefore, it is possible to mold a resin member with a disrupted filler orientation compared to when the uneven molding portion is not provided on the inner molding surface. This makes it possible to manufacture an electricity storage device with less anisotropy in the properties of the resin member.

[0013] When providing an uneven portion on the resin inner surface of the resin inner portion of the resin member, for example, as will be described later in embodiment 1, an uneven molded portion is provided in the mold used in the insert molding process. That is, the uneven molded portion is provided in the portion of the inner molded surface that forms the inner molded cavity, which is configured by the mold. Alternatively, as will be described in embodiment 3, an uneven molded portion is provided in the portion of the terminal member that joins to the resin inner surface. That is, the uneven molded portion can also be provided in the portion of the inner molded surface that forms the inner molded cavity, which is configured by the terminal member. On the other hand, when providing an uneven portion on the resin joining surface of the resin inner portion of the resin member, an uneven molded portion is provided on the portion of the case member that joins to the resin inner portion, as described in embodiment 2. That is, an uneven molded portion is provided on the portion of the inner portion molding surface that forms the inner portion molding cavity and that is configured by the case member.

[0014] (4) In the method for manufacturing the electricity storage device described in (3), the numerous convex portions and concave portions that make up the uneven portion may be arranged in a staggered pattern, and the numerous convex portion forming portions and concave portion forming portions that make up the uneven portion forming portion may be arranged in a staggered pattern.

[0015] In the manufacturing method of the electricity storage device described above, since the numerous convex and concave molded portions that make up the concave-convex molded portion are arranged in a staggered pattern, the orientation of the filler in the molten resin can be further disordered, and a resin member with a more disordered filler orientation can be molded. This makes it possible to manufacture an electricity storage device with less anisotropy in the properties of the resin member. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a battery according to a first embodiment. [Figure 2] 1 is a partial cross-sectional view of a battery according to a first embodiment taken along the battery height direction and battery width direction. [Figure 3] 6 is a cross-sectional view taken along the line AA in FIG. 5 in the battery height direction and battery width direction near the resin member according to the first embodiment. [Figure 4] 6 is a cross-sectional view taken along the arrow BB in FIG. 5 in the battery height direction and battery thickness direction near the resin member according to the first embodiment. FIG. [Figure 5] 2 is a plan view of the first embodiment, seen from inside the case lid member near the resin member. FIG. [Figure 6] 2 is a flowchart of a method for manufacturing a battery according to the first embodiment. [Figure 7] 4 is an explanatory view showing a state in which molten resin is injected into a cavity in an insert molding step in the manufacturing method of the battery according to the first embodiment. FIG. [Figure 8] 4 is an explanatory view showing a state in which a resin member is molded in an insert molding step in the manufacturing method of the battery according to the first embodiment. FIG. [Figure 9] 3 along the battery height direction and battery width direction in the vicinity of the resin member according to the second embodiment. FIG. [Figure 10] 8 is an explanatory view corresponding to FIG. 7, showing a state in which molten resin is injected into a cavity in an insert molding step in the manufacturing method of the battery according to the second embodiment. FIG. [Figure 11] 10 is a cross-sectional view corresponding to FIG. 3 taken along the battery height direction and battery width direction in the vicinity of a resin member according to a third embodiment. [Figure 12] 8 is an explanatory view corresponding to FIG. 7, showing a state in which molten resin is injected into a cavity in an insert molding step in the manufacturing method of the battery according to the third embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] (Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 shows a perspective view of a battery (energy storage device) 1 of this embodiment 1, and Fig. 2 shows a partial cross-sectional view of the battery 1. Figs. 3 and 4 show enlarged cross-sectional views of the vicinity of a resin member 50, and Fig. 5 shows an enlarged plan view of the vicinity of the resin member as seen from the inside EH. In the following description, the battery height direction AH, battery width direction BH, and battery thickness direction CH of the battery 1 are defined as the directions shown in Figs. 1 and 2. Battery 1 is a rectangular (rectangular) sealed lithium ion secondary battery that can be installed in vehicles such as hybrid cars, plug-in hybrid cars, and electric cars. Battery 1 is composed of a case 10, an electrode assembly 30 and an electrolyte 5 housed in case 10, and positive and negative terminal members 40 fixed to case 10 via resin members 50. Inside case 10, 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 having a rectangular opening 20c and a bottomed, square cylindrical shape that houses the electrode assembly 30, 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 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] 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.

[0020] Circular insertion holes 25h are provided near the ends of one side BH1 and the other side BH2 in the battery width direction BH of the case lid member 25. 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.

[0021] The positive and negative terminal members 40 have the same configuration, and will be described together below. The terminal member 40 is formed by welding an outer terminal portion (outer terminal member) 41 and an inner terminal portion (inner terminal member) 42 together. The outer terminal portion 41 is a rectangular plate extending in the battery width direction BH and the battery thickness direction CH, and is located on the outer side DH (upper side AH1 in the first embodiment) of the case lid member 25.

[0022] Meanwhile, the terminal inner portion 42 is located primarily on the inner side EH (the lower side AH2 in the first embodiment) of the case lid member 25 and is connected to the terminal outer portion 41 via the insertion hole 25h. The terminal inner portion 42 comprises a plate-shaped flange portion 44, a cylindrical protrusion portion 43 with a bottom that protrudes from the center of the flange portion 44 toward the upper side AH1, and an extension portion 45 that extends from the flange portion 44 toward the lower side AH2. The flange portion 44 has a rectangular outer periphery with a circular hole in the center and is disposed parallel to the case lid member 25. The protrusion portion 43 protrudes toward the outer side DH through the insertion hole 25h and is welded at its bottom to the terminal outer portion 41. The extension portion 45 bends at an end of the flange portion 44 on one side CH1 in the battery thickness direction CH and extends toward the lower side AH2. The positive electrode terminal member 40 is welded at the tip of its extension 45 to the positive electrode current collector 30c of the electrode body 30, and is electrically connected to the positive electrode current collector 30c. The negative electrode terminal member 40 is welded at the tip of its extension 45 to the negative electrode current collector 30d of the electrode body 30, and is electrically connected to the negative electrode current collector 30d.

[0023] Next, the resin member 50 will be described. The positive electrode resin member 50 is airtightly joined to the case lid member 25 and the terminal member 40 while insulating the case lid member 25 from the positive electrode terminal member 40, thereby fixing the terminal member 40 to the case lid member 25. The negative electrode resin member 50 is airtightly joined to the case lid member 25 and the terminal member 40 while insulating the case lid member 25 from the negative electrode terminal member 40, thereby fixing the terminal member 40 to the case lid member 25. The positive electrode and negative electrode side resin members 50 have similar shapes, and will be described together below.

[0024] The resin member 50 is made of a resin material 55 containing a thermoplastic main resin 56, a thermoplastic elastomer 57, and a fibrous filler 58. In the first embodiment, the thermoplastic main resin 56 is polyphenylene sulfide (PPS), the thermoplastic elastomer 57 is a thermoplastic polyurethane elastomer, and the fibrous filler 58 is a glass fiber having a diameter of approximately 10 μm and a length of 300 μm. The weight ratio of the main resin 56, the elastomer 57, and the filler 58 is main resin:elastomer:filler=40:10:50.

[0025] Resin member 50 is made up of a resin inner portion 52 located on the inside EH of case lid member 25, and a resin outer portion 51 extending from this resin inner portion 52 through insertion hole 25h to the outside DH of case lid member 25. Of these, resin outer portion 51 surrounds the periphery of terminal outer portion 41 to insulate between terminal outer portion 41 and case lid member 25, and also surrounds an upper outer peripheral surface 43d of upper side AH1 of protrusion 43 of terminal inner portion 42 to insulate between upper outer peripheral surface 43d of protrusion 43 and case lid member 25. On the other hand, the resin inner portion 52 is a roughly rectangular plate whose dimension in the battery width direction BH is longer than its dimension in the battery thickness direction CH, and surrounds the lower outer peripheral surface 43e of the lower side AH2 of the protrusion 43 of the terminal inner portion 42, thereby providing insulation between the lower outer peripheral surface 43e of the protrusion 43 and the case lid member 25, and also surrounds the periphery of the flange portion 44 of the terminal inner portion 42, thereby providing insulation between the flange portion 44 and the case lid member 25.

[0026] The resin inside portion 52 has a resin inside surface 52b facing the inside EH and a resin joining surface 52a facing the outside DH and joining to the case lid member 25. The resin inside surface 52b includes not only a portion exposed inside the case 10 but also a portion joining to the outer surface 44a of the flange 44 of the terminal member 40. In the first embodiment, of the resin joining surface 52a and the resin inside surface 52b, an uneven portion 52w is provided on the resin inside surface 52b. This uneven portion 52w is formed over 20% or more of the entire area of the resin inside surface 52b (approximately 50% in the first embodiment). The numerous convex portions 52t and concave portions 52v constituting the uneven portion 52w are arranged in a houndstooth pattern (see FIG. 5). As will be described later, the formation of this uneven portion 52w disrupts the orientation of the filler 58 contained in the resin inside portion 52 of the resin member 50.

[0027] In this battery 1, an uneven portion 52w is provided on the resin inner surface 52b of the resin inner portion 52 of the resin member 50. The uneven portion 52w causes the orientation of the filler 58 contained in the resin inner portion 52 to become disordered. Therefore, the orientation of the filler 58 in the resin inner portion 52 is more disordered than when the uneven portion 52w is not provided. Specifically, the amount of filler 58 oriented in a specific direction (the battery width direction BH in the first embodiment) is reduced in each region of the resin inner portion 52. Furthermore, the orientation of the filler 58 is not the same in adjacent regions of the resin member 50. For example, the orientation of the filler 58 changes between a region of the resin member 50 near the protrusion 52t and a region of the resin member 50 near the adjacent recess 52v. Therefore, the battery 1 exhibits less anisotropy in the properties (such as the linear expansion coefficient and strength) of the resin member 50 than when the uneven portion 52w is not provided. Furthermore, in the present embodiment 1, the numerous protrusions 52t and recesses 52v that make up the uneven portion 52w are arranged in a staggered pattern. Therefore, as the uneven portion 52w is formed, the orientation of the filler 58 contained in the resin inner portion 52 becomes more irregular. Therefore, in this battery 1, the resin member 50 has particularly little anisotropy in its properties.

[0028] Next, a method for manufacturing the battery 1 will be described (see FIGS. 6 to 8). The case lid member 25, the positive and negative terminal outer portions 41, and the terminal inner portions 42 are prepared in advance. Then, in the "terminal formation step S1" (see FIG. 6), the positive and negative terminal members 40 are formed. Specifically, the protruding portions 43 of the positive and negative terminal inner portions 42 are inserted into a pair of insertion holes 25h of the case lid member 25 from the inside EH to the outside DH of the case lid member 25. Thereafter, the positive and negative terminal outer portions 41 are abutted against the bottoms of the protruding portions 43 from the outside DH of the case lid member 25, and the protruding portions 43 and the terminal outer portions 41 are laser-welded to form the positive and negative terminal members 40. These terminal members 40 are inserted into the insertion holes 25h of the case lid member 25.

[0029] Next, in the "insert molding process S2" (see FIG. 6), the positive and negative terminal members 40 are inserted into the pair of insertion holes 25h of the case lid member 25, and the pair of resin members 50 are insert-molded using the above-mentioned resin material 55. This insert molding process S2 is performed using a molding die DE having an upper die DA and a lower die DB (see FIG. 7). The upper die DA has a pair of (positive electrode side and negative electrode side) outer surface molding portions DA1 that form the exposed surface 51m of the resin outer portion 51 of the resin member 50, and an outer lid contact portion DA2 that extends radially outward surrounding the outer surface molding portion DA1 and faces and contacts the outer surface 25a of the case lid member 25. On the other hand, the lower mold DB has a pair of inner surface molding portions DB1 (positive electrode side and negative electrode side) that form the exposed surface 52m of the resin inner portion 52 of the resin member 50, and an inner lid contact portion DB2 that surrounds the inner surface molding portion DB1, extends radially outward, and is in close contact with the inner surface 25b of the case lid member 25.

[0030] In the insert molding process S2, the molding die DE, the case lid member 25, and the pair of terminal members 40 form a pair of cavities FE for molding the pair of resin members 50. The cavities FE are made up of an outer portion molding cavity FA for molding the resin outer portion 51 of the resin member 50, and an inner portion molding cavity FB for molding the resin inner portion 52 of the resin member 50. Of these, the outer portion molding cavity FA is formed by the upper mold DA, the case lid member 25, and the terminal outer portion 41 of the terminal member 40 and the upper portion of the protruding portion 43 of the terminal inner portion 42. Specifically, the outer portion molding surface FAn that forms the outer portion molding cavity FA is composed of the outer molding surface DAn of the outer surface molding portion DA1 of the upper mold DA, the outer surface 25a of the case lid member 25 and the inner peripheral surface 25c of the insertion hole 25h, the inner surface 41b and outer peripheral surface 41d of the terminal outer portion 41, and the upper outer peripheral surface 43d of the protruding portion 43 of the terminal inner portion 42.

[0031] On the other hand, the inner portion molding cavity FB is formed by the lower mold DB, the case lid member 25, and the lower part of the flange portion 44 and the protrusion 43 of the terminal inner portion 42 of the terminal member 40. Specifically, the inner portion molding surface FBn constituting the inner portion molding cavity FB is composed of the inner molding surface DBn of the inner surface molding portion DB1 of the lower mold DB, the inner surface 25b of the case lid member 25, the outer surface 44a and outer peripheral surface 44d of the flange portion 44 of the terminal inner portion 42, and the lower outer peripheral surface 43e of the protrusion 43 of the terminal inner portion 42. Of these, the inner molding surface DBn of the inner surface molding portion DB1 has an uneven molding portion DBw that molds the uneven portion 52w of the resin inner portion 52 of the resin member 50. The uneven molding portion DBw has multiple convex portion molding portions DBt that mold multiple convex portions 52t and multiple concave portion molding portions DBv that mold multiple concave portions 52v, which are arranged in a staggered pattern.

[0032] A pair of injection nozzles NZ are arranged in the lower mold DB, and are configured so that molten resin 55M of the resin material 55 can be injected into each of the inner molding cavities FB from gates GT formed at the tip of each injection nozzle NZ. Because the inner molding cavity FB and the outer molding cavity FA are connected within the insertion hole 25h, the molten resin 55M injected into the inner molding cavity FB passes through the insertion hole 25h and fills each of the outer molding cavities FA, as shown by the arrow P in Figure 7, where the flow of the molten resin 55M is indicated.

[0033] In the insert molding process S2, a cavity forming process S21 is performed, followed by an injection molding process S22 (see FIG. 6). First, in the cavity forming step S21, a pair of cavities FE for molding a pair of resin members 50 are formed using a molding die DE, a case lid member 25, and a pair of terminal members 40 (see FIG. 7). Specifically, the case lid member 25 and the positive and negative terminal members 40 are placed in predetermined positions in a lower die DB. Then, an upper die DA is moved downward toward the lower die DB and placed on top of the lower die DB, and the molding die DE is closed. At this time, a portion of the outer surface molding portion DA1 of the upper die DA faces and closely contacts the terminal outer portion 41 of the terminal member 40, and an outer lid contact portion DA2 faces and closely contacts the outer surface 25a of the case lid member 25. This forms an outer portion molding cavity FA of the cavity FE. Furthermore, a portion of the inner surface molding portion DB1 of the lower die DB faces and closely contacts the flange portion 44 of the terminal inner portion 42 of the terminal member 40, and an inner lid contact portion DB2 faces and closely contacts the inner surface 25b of the case lid member 25. As a result, an inner molding cavity FB of the cavity FE is formed.

[0034] Next, in the injection molding step S22, molten resin 55M, which is a melted resin material 55, is injected into each cavity FE to fill the cavity FE and mold the resin member 50. Specifically, molten resin 55M is injected from each gate GT into each of the two inner portion molding cavities FB, and is spread throughout the entire inner portion molding cavity FB and the entire outer portion molding cavity FA connected to the inner portion molding cavity FB. During this process, because the uneven molding portion DBw is provided on the inner molding surface DBn of the inner surface molding portion DB1 of the lower mold DB, the flow of molten resin 55M is disrupted compared to when the uneven molding portion DBw is not provided, and the orientation of filler 58 in molten resin 55M is disrupted.

[0035] That is, when the concave-convex molded portion DBw is not provided, the molten resin 55M flows mainly in the longitudinal direction of the resin inside portion 52 (left-right direction in FIGS. 7 and 8, the battery width direction BH when the battery 1 is constructed), and the filler 58 in the molten resin 55M is also oriented along this flow (the filler 58 is oriented so that the longitudinal direction of the filler 58 is parallel to the flow of the molten resin 55M). In contrast, in the present embodiment 1, the concave-convex molded portion DBw disrupts the flow of the molten resin 55M, and the orientation of the filler 58 in the molten resin 55M is also disrupted.

[0036] The molten resin 55M is then cooled to form the resin member 50 that is airtightly bonded to the case lid member 25 and the terminal members 40. That is, the molten resin 55M that has filled the entire cavity FE is cooled to form a resin inner portion 52 in the inner portion molding cavity FB and a resin outer portion 51 in the outer portion molding cavity FA, thereby forming two resin members 50 consisting of the resin inner portion 52 and the resin outer portion 51 (see FIG. 8). This results in a resin member 50 in which the orientation of the filler 58 is more disordered than in a case in which the concave-convex molded portion DBw is not present. The upper mold DA is then moved upward, and the lid assembly 15 in which the positive and negative terminal members 40 are fixed to the case lid member 25 via the resin member 50 is removed from the lower mold DB.

[0037] Next, in the "electrode body connecting step S3" (see FIG. 6), an electrode body 30 is prepared by stacking a positive electrode plate 31, a negative electrode plate 32, and a separator 33, and the extension portion 45 of the positive electrode terminal member 40 of the lid assembly 15 is ultrasonically welded to the positive electrode current collecting portion 30c of the electrode body 30. Also, the extension portion 45 of the negative electrode terminal member 40 of the lid assembly 15 is ultrasonically welded to the negative electrode current collecting portion 30d of the electrode body 30. Thereafter, the electrode body 30 is wrapped in a bag-shaped insulating holder 7. Next, in the "electrode assembly accommodating / case forming process S4", a case body member 20 is prepared, the electrode assembly 30 covered with the insulating holder 7 described above is inserted into the case body member 20, 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 accommodating the electrode assembly 30 inside.

[0038] Next, in the "pouring and sealing step S5," the electrolyte 5 is poured into the case 10 through the pouring hole 25k, and the electrolyte 5 is impregnated into the electrode body 30. Thereafter, the pouring hole 25k is covered from the outside with a sealing member 12, and the sealing member 12 is laser-welded to the case 10 in an airtight manner. Next, in the "initial charging and aging step S6," a charging device (not shown) is connected to the battery 1, and the battery 1 is initially charged. After that, the initially charged battery 1 is left to stand for a predetermined time to age the battery 1. In this way, the battery 1 is completed.

[0039] In the above-described method for manufacturing the battery 1, in the insert molding step S2, the unevenly molded portion DBw provided on the inner molding surface FBn of the inner molding cavity FB disrupts the flow of the molten resin 55M, thereby disrupting the orientation of the filler 58 contained in the molten resin 55M. Therefore, compared to when the unevenly molded portion DBw is not provided on the inner molding surface FBn, it is possible to mold a resin member 50 in which the orientation of the filler 58 is disrupted. This allows the manufacture of a battery 1 in which the properties of the resin member 50 have little anisotropy. Furthermore, in the first embodiment, the numerous convex molding portions DBt and concave molding portions DBv that make up the concave-convex molding portion DBw are arranged in a staggered pattern, which further disrupts the orientation of the filler 58 in the molten resin 55M, thereby enabling the molding of a resin member 50 with a further disrupted orientation of the filler 58. This allows the manufacture of a battery 1 with particularly little anisotropy in the properties of the resin member 50.

[0040] (Embodiment 2) Next, a second embodiment will be described (see FIGS. 9 and 10). Note that the description of the same parts as those in the first embodiment will be omitted or simplified. In the battery 1 of the first embodiment, the uneven portion 52w is provided on the resin inner surface 52b of the resin inner surface 52b and the resin bonding surface 52a of the resin inside portion 52. In contrast, the battery 100 of the second embodiment differs in that the uneven portion 152w is provided on the resin bonding surface 152a of the resin inner surface 152b and the resin bonding surface 152a of the resin inside portion 152. In the manufacturing method of battery 1 according to embodiment 1, a concave-convex molded portion DBw is provided in the lower mold DB of the molding die DE to mold the resin inside portion 52 having the concave-convex portion 52w. In contrast, the manufacturing method of battery 100 according to embodiment 2 is different in that a concave-convex molded portion 125w is provided on the inner surface 25b of case lid member 25 to mold the resin inside portion 152 having the concave-convex portion 152w.

[0041] Specifically, in the resin member 150 according to the second embodiment, the shape of the resin outer portion 51 is the same as that of the resin outer portion 51 of the first embodiment, but the shape of the resin inner portion 152 is different from that of the resin inner portion 52 of the first embodiment. That is, the resin inner portion 152 is a generally rectangular plate-like member and has a resin inner side surface 152b facing the inner side EH and a resin joining surface 152a facing the outer side DH and joining to the case lid member 25. In the second embodiment, of the resin joining surface 152a and the resin inner side surface 152b, the resin joining surface 152a is provided with an uneven portion 152w in which numerous protrusions 152t and recesses 152v are arranged in a houndstooth pattern. Furthermore, the formation of this uneven portion 152w disrupts the orientation of the filler 58 contained in the resin inner portion 152 of the resin member 150. Accordingly, an unevenly formed portion 125w having a shape corresponding to the uneven portions 152w of the resin bonding surface 152a of the resin inner portion 152 is provided on the inner surface 25b of the case lid member 25. That is, the unevenly formed portion 125w has a large number of convex portion forming portions 125t that form a large number of convex portions 152t and a large number of concave portion forming portions 125v that form a large number of concave portions 152v, which are arranged in a staggered pattern.

[0042] In the battery 100 of the second embodiment, an uneven portion 152w is provided on the resin bonding surface 152a of the resin inside portion 152 of the resin member 150, and the molding of this uneven portion 152w causes the orientation of the filler 58 contained in the resin inside portion 152 to become disordered. Therefore, the orientation of the filler 58 is disordered in the resin inside portion 52 after molding, and the properties (linear expansion coefficient, strength, etc.) of the resin member 150 have little anisotropy. In particular, the protrusions 152t and recesses 152v that make up the uneven portion 152w are arranged in a houndstooth pattern, so the properties of the resin member 150 have particularly little anisotropy. Other parts similar to those of the first embodiment provide the same effects as those of the first embodiment.

[0043] Next, a description will be given of a method for manufacturing the battery 100. In the second embodiment, the terminal member 40 is formed by performing the terminal forming step S1 using a case lid member 25 having the concave-convex portion 125w on the inner surface 25b. Thereafter, in the insert molding step S2, a pair of resin members 150 are insert molded using resin material 55 (see FIG. 10). Of the molding dies DE, the upper die DA is the same as the upper die DA of embodiment 1, but the lower die DC is different from the lower die DB of embodiment 1. That is, the lower die DC of embodiment 2 has no concave-convex molded portion on the inner molding surface DCn of the inner surface molding portion DC1, and is flat.

[0044] In the second embodiment, the lower mold DC, the case lid member 25 having the uneven molding portion 125w, and the terminal member 40 form a pair of inner portion molding cavities FC that mold the resin inner portion 52 of the resin member 50. That is, the inner portion molding surface FCn that constitutes the inner portion molding cavity FC is formed by the inner molding surface DCn of the inner surface molding portion DC1 of the lower mold DC, the inner surface 25b having the uneven molding portion 125w of the case lid member 25, the outer surface 44a and outer peripheral surface 44d of the flange portion 44 of the terminal inner portion 42, and the lower outer peripheral surface 43e of the protrusion 43 of the terminal inner portion 42. In the insert molding process S2, when molten resin 55M is injected from gate GT into inner molding cavity FC, the flow of molten resin 55M is disturbed by uneven molding portion 125w provided on inner surface 25b of case lid member 25, and the orientation of filler 58 in molten resin 55M is disturbed. As a result, resin member 150 is molded with filler 58 in a state where the orientation is disturbed.

[0045] In the manufacturing method of the battery 100 of the second embodiment, in the insert molding step S2, the unevenly formed portion 125w provided on the inner surface 25b of the case lid member 25 disrupts the flow of the molten resin 55M and disrupts the orientation of the filler 58. This allows for the molding of a resin member 150 in which the orientation of the filler 58 is disrupted, thereby enabling the manufacturing of a battery 100 in which the properties of the resin member 150 have little anisotropy. In particular, the numerous protrusions 125t and recesses 125v that make up the unevenly formed portion 125w are arranged in a houndstooth pattern, which further disrupts the orientation of the filler 58 in the molten resin 55M, enabling the molding of a resin member 50 in which the orientation of the filler 58 is further disrupted. Other parts similar to those of the first embodiment provide the same functions and effects as those of the first embodiment.

[0046] (Embodiment 3) Next, a third embodiment will be described (see FIGS. 11 and 12). Note that descriptions of parts similar to those of the first or second embodiment will be omitted or simplified. In the battery 200 of the third embodiment, similarly to the first embodiment, an uneven portion 252w is provided on the resin inner surface 252b of the resin inner surface 252b and the resin bonding surface 252a of the resin inner portion 252. However, the third embodiment differs from the first embodiment in that, instead of providing an uneven portion on the lower mold of the molding die DE as in the first embodiment, an uneven portion 244w is provided on the flange portion 244 of the terminal inner portion 42 of the terminal member 40 to form the resin inner portion 252 having the uneven portion 252w.

[0047] Specifically, in the terminal member 40 according to the third embodiment, the shape of a flange 244 of the terminal inside portion 42 is different from the flange 44 of the first and second embodiments. That is, the flange 244 of the third embodiment has a shape that is longer in the battery width direction BH than the flange 44 of the first and second embodiments, and an outer surface 244a of the flange 244 is joined over a wide area to the resin inner side surface 252b of the resin inside portion 252 of the resin member 250. The outer surface 244a of the flange 244 is provided with an unevenly formed portion 244w in which numerous protrusions 244t and recesses 244v are arranged in a houndstooth pattern.

[0048] The resin member 250 according to the third embodiment includes a resin outer portion 51 similar to that of the first embodiment, and a resin inner portion 252 that is slightly different in shape from that of the first embodiment and is bonded over a large area to the outer surface 244a of the flange portion 244 of the terminal member 40. The resin inner portion 252 is generally rectangular plate-shaped and has a resin inner side surface 252b facing the inner side EH and a resin bonding surface 252a facing the outer side DH. The resin inner side surface 252b according to the third embodiment is provided with an uneven portion 252w in which numerous protrusions 252t and recesses 252v are arranged in a houndstooth pattern, corresponding to the uneven molded portion 244w of the outer surface 244a of the flange portion 244.

[0049] In the battery 200 of the third embodiment, an uneven portion 252w is provided on the resin inner surface 252b of the resin inner portion 252 of the resin member 250, and the molding of this uneven portion 252w causes the orientation of the filler 58 contained in the resin inner portion 252 to become disordered. Therefore, the orientation of the filler 58 is disordered in the resin inner portion 252 after molding, and the properties of the resin member 250 have little anisotropy. Other parts similar to those of the first or second embodiment have the same effects as those of the first or second embodiment.

[0050] Next, a description will be given of a method for manufacturing the battery 200. In the third embodiment, the terminal forming step S1 is performed using the terminal inner part 42 having the concave-convex part 244w on the flange part 244 to form the terminal member 40. Thereafter, in the insert molding step S2, a pair of resin members 250 are insert molded using a resin material 55 (see FIG. 12). The molding die DE has an upper die DA and a lower die DC similar to those in the second embodiment.

[0051] In the third embodiment, the lower mold DC, the case lid member 25, and the terminal member 40 having the unevenly molded portion 244w form a pair of inner portion molding cavities FD that mold the resin inner portion 252 of the resin member 250. That is, the inner portion molding surface FDn that constitutes the inner portion molding cavity FD is formed by the inner molding surface DCn of the inner surface molding portion DC1 of the lower mold DC, the inner surface 25b of the case lid member 25, the outer surface 244a and outer peripheral surface 44d having the unevenly molded portion 244w of the flange portion 244 of the terminal inner portion 42, and the lower outer peripheral surface 43e of the protruding portion 43 of the terminal inner portion 42. In the insert molding process S2, when molten resin 55M is injected from gate GT into inner molding cavity FD, the flow of molten resin 55M is disturbed by the uneven molding portion 244w provided on the outer surface 244a of flange portion 244, and the orientation of filler 58 in molten resin 55M is disturbed. As a result, resin member 250 is molded with filler 58 in a state where the orientation is disturbed.

[0052] In the manufacturing method of the battery 200 of the third embodiment, in the insert molding step S2, the uneven molding portion 244w provided on the flange portion 244 of the terminal inner portion 42 of the terminal member 40 disrupts the flow of the molten resin 55M and disrupts the orientation of the filler 58. This makes it possible to mold a resin member 250 in which the orientation of the filler 58 is disrupted, and to manufacture a battery 200 in which the characteristics of the resin member 250 have little anisotropy. Other parts similar to those of the first or second embodiment provide the same effects as those of the first or second embodiment.

[0053] The present invention has been described above in accordance with embodiments 1 to 3, but it goes without saying that the present invention is not limited to embodiments 1 to 3 and can be modified and applied as appropriate within the scope of the gist of the present invention. [Explanation of symbols]

[0054] 1,100,200 Batteries (energy storage devices) 10 cases 25 Case cover member (case member) 25h insertion hole 40 Terminal member 50,150,250 Resin material 51 Resin outer part 52,152,252 Resin inner part 52a,152a,252a Resin joint surface 52b,152b,252b Resin inner surface 52w,152w,252w Uneven part 52t, 152t, 252t convex part 52v,152v,252v recess 55 Resin material 55M molten resin 56 Main Resin 58 Filler DH (Case lid) Outside EH (Inside of case cover) DE molding die DBw (Provided in the molding die) Concave and concave molding part DBt (Protruding part provided on the molding die) DBv (formed in the molding die) recessed portion 125w (Provided on the case cover) 125t Convex molding part (provided on the case lid material) 125v Recessed portion (provided on the case cover) 244w (Provided on the flange of the terminal) 244t (Protruding portion formed on the flange of the terminal member) 244v (Provided on the flange of the terminal member) Recessed molding portion FB, FC, FD inner molding cavity FBn,FCn,FDn Inner molding surface S2 Insert molding process S21 Cavity forming process S22 Injection molding process

Claims

1. a case member including an insertion hole; a terminal member inserted into the insertion hole of the case member; 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 made of a resin material containing a thermoplastic main resin and a fibrous filler, and is formed by insert molding. An electricity storage device, The resin member is a resin inner portion located inside the case member; a resin outer portion extending from the resin inner portion through the insertion hole to the outside of the case member, The resin inner portion has an uneven portion provided on at least one of the resin inner surface facing inward and the resin joining surface facing outward and joined to the case member, and the orientation of the filler contained in the resin inner portion is disturbed by molding the uneven portion. Energy storage device.

2. The electricity storage device according to claim 1 , The numerous convex and concave portions that make up the uneven portion are arranged in a staggered pattern. Energy storage device.

3. a case member including an insertion hole; a terminal member inserted into the insertion hole of the case member; 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 made of a resin material containing a thermoplastic main resin and a fibrous filler, and is insert-molded; The resin member is a resin inner portion located inside the case member; a resin outer portion extending from the resin inner portion through the insertion hole to the outside of the case member, The resin inner portion has an uneven portion provided on at least one of the resin inner surface facing inward and the resin joining surface facing outward and joined to the case member, and the orientation of the filler contained in the resin inner portion is disturbed by molding the uneven portion. A method for manufacturing an electricity storage device, comprising: an insert molding step of insert-molding the resin member using the resin material in a state where the terminal member is inserted into the insertion hole of the case member, The insert molding process includes: a cavity forming step of forming a cavity for molding the resin member by a molding die, the case member, and the terminal member; an injection molding step of injecting molten resin of the resin material into the cavity and filling the cavity with the molten resin to mold the resin member, The cavity is an outer portion molding cavity for molding the resin outer portion; and an inner portion molding cavity for molding the resin inner portion, The inner molding surface forming the inner molding cavity is a concave-convex molding portion that molds the concave-convex portion, The injection molding step includes: The flow of the molten resin is disturbed by the uneven molding portion, and the resin inner portion having the uneven portion is molded while disturbing the orientation of the filler contained in the molten resin. A method for manufacturing an electricity storage device.

4. A method for manufacturing the electricity storage device according to claim 3, The numerous convex portions and concave portions constituting the concave-convex portion are arranged in a staggered pattern, The plurality of convex and concave molding portions constituting the concave and convex molding portion are arranged in a staggered pattern. A method for manufacturing an electricity storage device.

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