Manufacturing method of power storage device and power storage device

Abstract

To prevent a resin from adhering to a connection surface of an electrode terminal.SOLUTION: A manufacturing method disclosed herein includes the steps of: preparing a case component having a through hole; inserting an electrode terminal into the through hole; disposing the case component and an electrode terminal 20 in an internal cavity of a mold M; and injecting a resin R into the internal cavity of the mold M. The electrode terminal 20 has a shaft part 22 and a plate part 24. The plate part 24 includes a connection surface 24a, a rear surface 24b, and a side surface 24c. A cavity surface Mcs of the mold M includes: a first surface M1 in surface contact with the connection surface 24a of the plate part 24; a second surface M2 facing the side surface 24c of the plate part 24 with a space therebetween; and a convex part M1a protruding from the first surface M1 toward a peripheral edge part 24a1 of the connection surface 24a. In an injection of the resin R, an injection amount of the resin R into the internal cavity Mc is controlled so that the resin R flowing into a resin flow path Mc3 is blocked by the convex part M1a. This can prevent the resin R from adhering to the connection surface 24a.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing an electricity storage device and an electricity storage device. [Background technology]

[0002] Power storage devices such as secondary batteries are used as power sources for various electrical appliances. These power storage devices include an electrode assembly and a case that houses the electrode assembly. The case includes, for example, a box-shaped case body with an opening and a sealing plate that closes the opening of the case body. The case also includes electrode terminals that are connected to external conductive parts (such as bus bars) and a sealant that insulates the electrode terminals from the case.

[0003] An example of such a case for an electricity storage device is disclosed in Japanese Patent Application Laid-Open No. 2022-103899. The lid (sealing plate) described in this document includes a terminal member (electrode terminal), a sealing plate having a mounting hole for mounting the terminal member, and a resin sealing material. The terminal member is attached to the mounting hole of the sealing plate while bonded to the sealing material. This sealing material is formed by injection molding. Specifically, first, a mold having an internal cavity shaped according to the sealing material is prepared. Next, the sealing plate and terminal member are placed in the internal cavity of this mold. Then, the internal cavity of the mold is filled with resin. This makes it possible to easily form a sealing material integrated with the sealing plate and terminal member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-103899 Summary of the Invention [Problem to be solved by the invention]

[0005] To connect to external conductive parts such as bus bars, electrode terminals must have a connection surface that is exposed to the outside when attached to a case. The external conductive part is connected to the center of this connection surface. However, if the component tolerances of each component (mold, sealing plate, electrode terminal, etc.) become large during injection molding of the sealing material, resin may adhere to the center of the connection surface of the electrode terminal. In this case, processing to remove the resin is required, which reduces the manufacturing efficiency of the electricity storage device. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a method for manufacturing an electricity storage device (hereinafter, also simply referred to as "manufacturing method") having the following configuration is provided.

[0007] The method for manufacturing an electricity storage device disclosed herein includes the steps of preparing a case component having a through hole, inserting an electrode terminal into the through hole, arranging the case component and the electrode terminal in an internal cavity of a mold, and injecting resin into the internal cavity of the mold to integrally mold the case component and a sealant that seals the through hole. In this manufacturing method, the electrode terminal has a shaft portion that is inserted into the through hole and a plate portion that is arranged to fit along the case component when the shaft portion is inserted into the through hole. The plate portion also has a connection surface exposed to the outside of the case component, a back surface opposite the connection surface, and a side surface that is continuous with the connection surface and the back surface. Meanwhile, the mold has a first surface that is a cavity surface that is in surface contact with at least the peripheral edge of the connection surface of the plate portion, a third surface that is a cavity surface that faces the side surface of the plate portion at a distance, and a protrusion that protrudes from the first surface toward the peripheral edge of the connection surface. In the manufacturing method disclosed herein, during the integral molding process, the amount of resin injected into the internal cavity is controlled so that the resin that reaches the space between the peripheral edge of the connection surface and the first surface via the resin flow path between the side surface and the third surface is blocked by the convex portion.

[0008] Generally, a space (resin flow path) is formed between the side of the plate portion of the electrode terminal and the cavity surface (second surface) of the mold. The resin supplied to this resin flow path serves as a side protection portion that prevents electrical conduction between the plate portion of the electrode terminal and the case. However, the side of the plate portion of the electrode terminal is continuous with the connection surface. Therefore, if a gap occurs between the cavity surface (first surface) of the mold and the connection surface of the electrode terminal, there is a risk that resin will infiltrate into the gap between the first surface and the connection surface through the resin flow path. In response to this, the cavity surface of the mold used in the manufacturing method disclosed herein has a protrusion that protrudes from the first surface toward the periphery of the connection surface. This protrusion can block the resin that reaches the periphery of the connection surface through the resin flow path. This prevents the resin from adhering to the center of the connection surface. As a result, the frequency of removing resin adhering to the center of the connection surface is reduced, contributing to improved manufacturing efficiency of electricity storage devices. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a flowchart illustrating the manufacturing method according to the first embodiment. [Figure 2] FIG. 2 is a perspective view schematically showing a sealing plate used in the manufacturing method according to the first embodiment. [Figure 3] FIG. 3 is a perspective view schematically showing an electrode terminal used in the manufacturing method according to the first embodiment. [Figure 4] FIG. 4 is a perspective view schematically showing an insertion step in the manufacturing method according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view schematically showing the accommodation step of the manufacturing method according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view schematically showing the injection step of the manufacturing method according to the first embodiment. [Figure 7] FIG. 7 is an enlarged cross-sectional view schematically showing the injection step of the manufacturing method according to the first embodiment. [Figure 8] FIG. 8 is a perspective view schematically showing the electricity accumulation device according to the first embodiment. [Figure 9]FIG. 9 is an enlarged cross-sectional view schematically showing the structure in the vicinity of an electrode terminal of the electricity storage device according to the first embodiment. [Figure 10] FIG. 10 is an enlarged cross-sectional view schematically showing the injection step of the manufacturing method according to the second embodiment. [Figure 11] FIG. 11 is a cross-sectional view that schematically shows an injection step in a manufacturing method that does not employ the technology disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings. It should be noted that matters other than those specifically mentioned in this specification that are necessary for implementing the technology disclosed herein (e.g., detailed materials for the electrode body and electrolyte) can be understood as design matters for a person skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in the relevant field. Furthermore, the expression "A to B" indicating a range in this specification is intended to include the meaning of "greater than A" and "smaller than B" as well as the meaning of "greater than A" and "smaller than B."

[0011] In this specification, the term "electricity storage device" refers to a concept that encompasses devices in which charge and discharge reactions occur due to the movement of charge carriers between a pair of electrodes (positive and negative electrodes). That is, the electricity storage device in the technology disclosed herein encompasses secondary batteries such as lithium ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, as well as capacitors such as lithium ion capacitors and electric double layer capacitors.

[0012] First Embodiment 1. Manufacturing method of electricity storage device Hereinafter, one embodiment of the manufacturing method for the electricity storage device disclosed herein will be described with reference to the drawings. Note that the symbols L, R, F, Rr, U, and D in the drawings referred to in this specification represent left, right, front, rear, top, and bottom, respectively. Furthermore, the symbols X, Y, and Z in the drawings represent the width direction, depth direction, and height direction of the electricity storage device, respectively. However, these directions are merely defined for the convenience of explanation and do not limit the installation mode of each component in the technology disclosed herein.

[0013] Fig. 1 is a flowchart illustrating a manufacturing method according to the first embodiment. As shown in Fig. 1, the manufacturing method according to this embodiment includes a preparation step S10, an insertion step S20, a storage step S30, and a pouring step S40. Each step will be described below.

[0014] (1) Preparation process S10 In this step, a case component having a through hole is prepared. In this specification, the term "case component" refers to a component, among the multiple components constituting the case of an electricity storage device, to which electrode terminals and a sealant are attached. For example, an electricity storage device 100 shown in FIG. 8 (described later) uses a case 10 including a case main body 12 and a sealing plate 14. In this electricity storage device 100, electrode terminals 20 and a sealant 30 are attached to the sealing plate 14. In this configuration, the sealing plate 14 is the case component. However, the case component is not limited to the sealing plate. For example, when electrode terminals and a sealant are attached to the case main body, the case main body is the case component.

[0015] FIG. 2 is a perspective view schematically illustrating a sealing plate used in the manufacturing method according to the first embodiment. As shown in FIG. 2, the case component (sealing plate 14) in this embodiment is a long, plate-like member extending in the width direction X. A through hole 14a is provided at each of both ends of the sealing plate 14 in the width direction X. The through hole 14a in FIG. 2 is a rectangular opening in plan view. However, the planar shape of the through hole 14a is not particularly limited as long as it allows insertion of an electrode terminal 20, which will be described later. Other examples of the planar shape of the through hole 14a include a circle and an ellipse. An outer surface 14b of the sealing plate 14 has an outer groove 14d surrounding the through hole 14a. Similarly, an inner surface 14c of the sealing plate 14 also has an inner groove 14e surrounding the through hole 14a (see FIG. 5). As will be described in detail later, the outer groove 14d and the inner groove 14e can contribute to improving the adhesion between the sealing plate 14 and the sealant 30 after injection molding.

[0016] (2) Insertion step S20 Fig. 3 is a perspective view schematically showing an electrode terminal used in the manufacturing method according to the first embodiment. Fig. 4 is a perspective view schematically showing an insertion step of the manufacturing method according to the first embodiment. As shown in Fig. 4, in the insertion step S20, the electrode terminal 20 is inserted into the through-hole 14a. As shown in Fig. 3, the electrode terminal 20 in this embodiment is an elongated member extending in the height direction Z. This electrode terminal 20 has a shaft portion 22 and a plate portion 24.

[0017] The shaft portion 22 is a portion that is inserted into the through-hole 14a. This shaft portion 22 is housed inside the case 10 in the manufactured electricity storage device 100. As shown in FIGS. 3 and 9, the shaft portion 22 in this embodiment is an elongated plate-like member that extends in the height direction Z. As will be described in detail later, in the manufactured electricity storage device 100, a lower end portion 22b of the shaft portion 22 is connected to the electrode body 40 (see FIG. 9). Note that the shape of the shaft portion 22 is not limited to a plate shape, and may be a columnar shape (cylindrical, rectangular), etc.

[0018] The plate portion 24 is a member disposed along the case component (sealing plate 14) when the shaft portion 22 is inserted into the through hole 14a. As shown in FIG. 3 , the plate portion 24 in this embodiment extends continuously from the upper end of the shaft portion 22 in the width direction X. The plate portion 24 is formed by bending the tip of a long, plate-shaped conductive member. The planar shape of the plate portion 24 is generally rectangular. As shown in FIG. 4 , the insertion position of the electrode terminal 20 in a plan view is adjusted so that the generally rectangular plate portion 24 covers an upper portion U of the generally rectangular through hole 14a. Thus, the planar shape of the plate portion preferably corresponds to the planar shape of the through hole. For example, if the planar shape of the through hole is circular, the planar shape of the plate portion should also be circular. This facilitates the filling of the resin in the injection step S40 described below. The electrode terminal does not necessarily have to be an integrated component in which the shaft portion and the plate portion are continuous. For example, the shaft portion and the plate portion may be separately manufactured and then assembled to form the electrode terminal.

[0019] In this embodiment, the plate portion 24 includes a connection surface 24a exposed to the outside of the case component (sealing plate 14), a back surface 24b opposite the connection surface 24a, and a side surface 24c continuous with the connection surface 24a and the back surface 24b. As shown in FIG. 9 (described later), when an electricity storage device 100 is constructed, the connection surface 24a of the plate portion 24 is disposed outside the case 10. This allows an external conductive component, such as a bus bar, to be connected to the plate portion 24 of the electrode terminal 20. The back surface 24b and the side surface 24c of the plate portion 24 are covered with a sealing material 30. Note that the insertion height of the electrode terminal 20 is preferably adjusted so that the back surface 24b of the plate portion 24 is disposed above the outer surface 14b of the sealing plate 14. This ensures a sufficient flow path between a first filling space Mc1 and a fourth filling space Mc4 (described later). As a result, the base portion 32 and the outer insulating portion 38 of the sealing material 30 in FIG. 9 are properly formed, so that the components can be fixed more stably.

[0020] Furthermore, in the electrode terminal 20 of this embodiment, a recess 24e recessed from the connecting surface 24a is formed on a peripheral edge 24a1 of the connecting surface 24a. This recess 24e is an annular groove continuously formed along the peripheral edge 24a1 of the connecting surface 24a. As will be described in detail later, this recess 24e is formed so as to fit over a protrusion M1a (see FIG. 7) of a mold M.

[0021] (3) Storage process S30 FIG. 5 is a cross-sectional view schematically illustrating the accommodation step of the manufacturing method according to the first embodiment. As shown in FIG. 5, in the accommodation step S30, the case component (sealing plate 14) and the electrode terminal 20 are placed in the internal cavity Mc of the mold M. Specifically, the internal cavity Mc of the mold M accommodates the periphery of the through hole 14a of the sealing plate 14, the entire plate portion 24, and the upper end portion 22a of the stem portion 22. Although not shown, the lower end portion 22b (see FIG. 3) of the stem portion 22 and the central portion 14f (see FIG. 1) of the sealing plate 14 in the width direction X are not accommodated in the internal cavity Mc and are exposed to the outside of the mold M. In addition, in the accommodation step S30 of this embodiment, the electrode terminal 20 and the sealing plate 14 are reversed upside down. As a result, the back surface 24b of the plate portion 24 and the inner surface 14c of the sealing plate 14 are arranged in the upper U direction. In this case, the resin R is more likely to flow into the resin flow path Mc3 when the temperatures of the electrode terminal 20 and the mold M are low at the beginning of the injection step S40 described below. As a result, the resin R can be more effectively prevented from entering the resin blocking portion Mc0.

[0022] The mold M used in this step is made of a high-strength metal material such as stainless steel, die steel, or maraging steel. This makes it possible to prevent deformation or damage to the mold M during the injection step S40. Inside the mold M, a cavity surface Mcs is formed that corresponds to the shape of the sealing material 30 to be molded. In this specification, the "internal cavity Mc of the mold M" refers to the space surrounded by the cavity surface Mcs of the mold M. In this embodiment, the cavity surface Mcs has the following first surface M1 to fourth surface M4.

[0023] (a) First side M1 As shown in FIG. 5, the first surface M1 is a cavity surface Mcs that is in surface contact with at least the peripheral edge 24a1 of the connecting surface 24a of the plate portion 24. Bringing the peripheral edge 24a1 of the connecting surface 24a and the first surface M1 into surface contact in this manner prevents resin from penetrating into the central portion 24a2 of the connecting surface 24a. In this embodiment, the first surface M1 is a flat surface that is in surface contact with the entire connecting surface 24a of the plate portion 24. In other words, the first surface M1 in this embodiment is in surface contact not only with the peripheral edge 24a1 of the connecting surface 24a but also with the central portion 24a2 of the connecting surface 24a. This more effectively prevents resin from adhering to the central portion 24a2 of the connecting surface 24a. In this specification, the region where the central portion 24a2 of the connecting surface 24a and the first surface M1 are in surface contact is referred to as the "resin blocking portion Mc0."

[0024] The mold M in this embodiment has a protrusion M1a that protrudes from the first surface M1 toward the peripheral edge 24a1 of the connecting surface 24a of the plate portion 24. As will be described in detail later, this protrusion M1a has the function of blocking the resin that flows from the peripheral edge 24a1 of the connecting surface 24a toward the central portion 24a2. This prevents the resin from adhering to the central portion 24a2 of the connecting surface 24a. Note that the protrusion M1a in this embodiment is an annular protrusion that is continuously provided in the circumferential direction so as to face the entire circumference of the peripheral edge 24a1 of the connecting surface 24a of the plate portion 24.

[0025] As shown in FIG. 5, the dimension L1 of the first surface M1 in the depth direction Y is preferably longer than the dimension LT of the plate portion 24 in the depth direction Y. This facilitates surface contact of the connection surface 24a of the plate portion 24 with the first surface M1. Specifically, if the dimension LT of the plate portion 24 and the dimension L1 of the first surface M1 are substantially equal, the plate portion 24 may ride up onto the third surface M3 of the mold M. In this case, a gap is generated in the resin blocking portion Mc0, increasing the likelihood of resin adhering to the connection surface 24a. In contrast, if the first surface M1 is wider than the plate portion 24, surface contact between the first surface M1 and the connection surface 24a is facilitated, thereby more effectively preventing resin from adhering to the connection surface 24a. For example, the difference (L1 - LT) between the dimension L1 of the first surface M1 and the dimension LT of the plate portion 24 is preferably 0.001 mm or more, more preferably 0.005 mm or more, and particularly preferably 0.01 mm or more. On the other hand, if the difference (L1-LT) between the dimension L1 of the first surface M1 and the dimension LT of the plate portion 24 becomes too large, the resin will be more likely to reach the tip Mc3a of the resin flow path Mc3 described below. From this perspective, the difference (L1-LT) between the dimension L1 of the first surface M1 and the dimension LT of the plate portion 24 is preferably 0.2 mm or less, more preferably 0.15 mm or less, and particularly preferably 0.1 mm or less.

[0026] (b) Second side M2 The second surface M2 is a cavity surface Mcs that faces the back surface 24b of the plate portion 24 with a gap therebetween. A space is formed between the second surface M2 and the back surface 24b, into which resin is filled in the injection step S40. In the following description, this space is referred to as a "first filling space Mc1." The resin filled in the first filling space Mc1 becomes the base portion 32 of the sealing material 30 (see FIG. 9).

[0027] Furthermore, the dimension L2 of the second surface M2 in the depth direction Y is longer than the dimension LT of the plate portion 24 in the depth direction Y. Both end portions of the second surface M2 in the depth direction Y extend beyond the plate portion 24 and face the inner surface 14c of the sealing plate 14. Hereinafter, the space where both end portions of the second surface M2 face the inner surface 14c of the sealing plate 14 is referred to as the "second filling space Mc2." The resin filled in this second filling space Mc2 becomes the internal insulating portion 34 of the sealing material 30 (see FIG. 9). Note that the second surface M2 of the mold M extends outward (toward the front F and the rear Rr) beyond the internal groove 14e of the sealing plate 14. As a result, the internal insulating portion 34 is formed to cover the internal groove 14e. This improves the adhesion between the sealing material 30 and the sealing plate 14. Furthermore, the resin supplied to the second filling space Mc2 enters the internal groove 14e and then reaches the contact surface Ma between the inner side surface 14c of the sealing plate 14 and the mold M. This prevents a large amount of resin from being suddenly supplied to the contact surface Ma, thereby suppressing leakage of the resin to the outside of the mold M.

[0028] (c) Third side M3 The third surface M3 is a cavity surface Mcs that faces the side surface 24c of the plate portion 24 with a gap therebetween. A resin flow path Mc3 into which the resin flows is formed between the third surface M3 and the side surface 24c. The resin filled in the resin flow path Mc3 becomes a side surface protection portion 36 that covers the side surface 24c of the plate portion 24 (see FIG. 9). As will be described in detail later, the side surface protection portion 36 serves as an insulating member that prevents electrical conduction between the plate portion 24 and the case 10 (sealing plate 14). Furthermore, as shown in FIG. 5, a tip end Mc3a of the resin flow path Mc3 is adjacent to a resin blocking portion Mc0.

[0029] In this embodiment, the cavity surface Mcs (i.e., the third surface M3) that forms the resin flow path Mc3 is continuous along the circumferential direction of the side surface 24c of the plate portion 24. As a result, in the manufactured power storage device 100, a side surface protection portion 36 that continuously covers the side surface 24c of the plate portion 24 is formed. This makes it possible to more suitably suppress conduction between the plate portion 24 and the case 10 (sealing plate 14). Furthermore, the technology disclosed herein can suppress the resin R from entering the resin blocking portion Mc0 via the tip end Mc3a of the resin flow path Mc3. Therefore, even when a resin flow path Mc3 that is continuous in the circumferential direction is formed, it is possible to suppress adhesion of resin to the connection surface 24a of the plate portion 24.

[0030] (d) 4th side M4 Next, the fourth surface M4 is a cavity surface Mcs that faces the outer surface 14b of the sealing plate 14 with a gap therebetween. The space where the fourth surface M4 of the mold M and the outer surface 14b of the sealing plate 14 face each other is referred to as the "fourth filling space Mc4." The resin filled in this fourth filling space Mc4 becomes the outer insulating portion 38 of the sealing material 30 (see FIG. 9). Note that the fourth surface M4 of the mold M extends outward beyond the outer groove 14d of the outer surface 14b of the sealing plate 14. As a result, an inner insulating portion 34 that covers the outer groove 14d is formed. This improves the adhesion between the sealing material 30 and the sealing plate 14. Furthermore, like the inner groove 14e, the outer groove 14d also functions to prevent resin leakage from the contact surface Mb between the outer surface 14b of the sealing plate 14 and the mold M.

[0031] (4) Injection process S40 FIG. 6 is a cross-sectional view schematically illustrating the injection step of the manufacturing method according to the first embodiment. As shown in FIG. 6, in this step, resin R is injected into the internal cavity Mc of the mold M. This allows the case component (sealing plate 14) and the sealant 30 (see FIG. 9) that seals the through-hole 14a to be integrally molded. The sealant 30 also integrates with the electrode terminal 20 (specifically, the plate portion 24 and the upper end 22a of the shaft portion 22) inserted into the through-hole 14a. Examples of the resin R filled in this step include thermoplastic resins such as polyethylene, polyamide, polypropylene, and vinyl chloride resin. The sealant 30 can be easily formed by injecting these thermoplastic resins into the internal cavity Mc and cooling them.

[0032] The injection of the resin R in this process will be described below. The mold M in this embodiment has an injection hole Ms penetrating the mold M. This injection hole Ms is formed on the second surface M2 so as to face the back surface 24b of the plate portion 24. The injection hole Ms is also connected to a resin supply source (not shown) via a transfer pipe P. The resin R supplied from the resin supply source is injected into the internal cavity Mc of the mold M via the transfer pipe P and the injection hole Ms. The injected resin R is first filled into the first filling space Mc1, which is the space with the largest volume. The resin R is then supplied via this first filling space Mc1 to the second filling space Mc2, resin flow path Mc3, fourth filling space Mc4, etc. This prevents a large amount of resin R from being suddenly supplied into a relatively narrow space, thereby suppressing resin leakage and molding defects. In particular, by supplying the resin R to the resin flow path Mc3 via the first filling space Mc1, the supply speed of the resin R toward the tip Mc3a of the resin flow path Mc3 decreases, which makes it possible to more effectively suppress the intrusion of the resin R into the resin blocking portion Mc0.

[0033] As described above, the mold M in this embodiment includes a protrusion M1a protruding from the first surface M1 toward the peripheral edge 24a1 of the connecting surface 24a of the plate portion 24. In this process, the amount of resin R injected into the internal cavity Mc is controlled so that the resin R that reaches the gap between the peripheral edge 24a1 of the connecting surface 24a and the first surface M1 via the resin flow path Mc3 between the side surface 24c and the third surface M3 is blocked by the protrusion M1a. This prevents the resin R from adhering to the central portion 24a2 of the connecting surface 24a. This will be explained in comparison with an embodiment that does not employ the technology disclosed herein. FIG. 7 is an enlarged cross-sectional view schematically illustrating the injection process of the manufacturing method according to the first embodiment. FIG. 11 is a cross-sectional view schematically illustrating the injection process of the manufacturing method that does not employ the technology disclosed herein.

[0034] The mold N shown in FIG. 11 has a first surface N1 that comes into surface contact with the connecting surface 124a of the plate portion 124 and a third surface N3 that faces the side surface 124c of the plate portion 124 with a gap therebetween. In this case, a resin flow path Nc3 is formed between the side surface 124c and the third surface N3. The tip Nc3a of this resin flow path Nc3 is adjacent to the portion where the connecting surface 124a and the first surface N1 come into surface contact. Therefore, if a gap S occurs between the connecting surface 124a and the first surface N1 due to component tolerances or the like, resin R can easily enter the gap S through the tip Nc3a of the resin flow path Nc3. As a result, resin adheres to the center portion 124a2 of the connecting surface 124a of the plate portion 124, requiring a process to remove the resin.

[0035] On the other hand, as shown in FIG. 7 , in this embodiment, a protrusion M1a protrudes from the first surface M1 of the mold M toward the peripheral portion 24a1 of the connecting surface 24a of the plate portion 24. This protrusion M1a is interposed between the tip Mc3a of the resin flow path Mc3 and the central portion 24a2 of the connecting surface 24a. Therefore, the protrusion M1a can block the resin R that reaches the peripheral portion 24a1 of the connecting surface 24a via the tip Mc3a of the resin flow path Mc3. Therefore, according to the manufacturing method of this embodiment, even if the connecting surface 24a and the first surface M1 do not achieve sufficient surface contact due to component tolerances or the like, causing a gap in the resin blocking portion Mc0, adhesion of the resin R to the central portion 24a2 of the connecting surface 24a can be suppressed. This reduces the frequency of the resin removal process after the injection step S40, thereby contributing to improved manufacturing efficiency of the electricity storage device 100.

[0036] Even if the first surface M1 has a protrusion M1a, if an excessive amount of low-viscosity resin R is injected into the internal cavity Mc, the resin R may seep beyond the protrusion M1a and reach the central portion 24a2 of the connecting surface 24a. Therefore, in the injection step S40 of this embodiment, the amount of resin R injected into the internal cavity Mc is controlled so that the resin R reaching the peripheral portion 24a1 of the connecting surface 24a is blocked by the protrusion M1a. This appropriately prevents the resin R from adhering to the central portion 24a2 of the connecting surface 24a. The timing for stopping the injection of the resin R varies depending on the viscosity of the resin R, the injection rate of the resin R, the dimensions of the resin flow path Mc3, the protrusion amount of the protrusion M1a, and other factors, and is therefore not limited to a specific injection time. For example, after determining the dimensions and type of resin for each component, a preliminary test may be conducted to examine the relationship between the amount of resin R adhering to the central portion 24a2 of the connecting surface 24a and the injection conditions (injection rate and injection time). Based on the results of this preliminary test, the appropriate timing for stopping the injection of resin R can be determined.

[0037] As described above, the protrusions M1a in this embodiment are annular protrusions continuously provided in the circumferential direction so as to face each other around the entire circumference of the peripheral portion 24a1 of the connecting surface 24a of the plate portion 24. This annular protrusion M1a can prevent the resin R from infiltrating from the tip Mc3a of the resin flow path Mc3 to the resin blocking portion Mc0 along the entire circumference. As a result, adhesion of the resin R to the central portion 24a2 of the connecting surface 24a can be more reliably suppressed. Note that forming an annular protrusion is not essential to the technology disclosed herein. Specifically, the position of the resin R infiltrating circumferentially around the connecting surface 24a of the plate portion 24 varies depending on various factors (e.g., mold shape, electrode terminal shape, injection hole position, resin viscosity, resin injection speed, etc.). Therefore, if the positions where the resin R is likely to infiltrate are known in advance, localized protrusions may be formed in the prone-to-infiltrate areas. For example, the amount of resin R infiltrating tends to be greater in the peripheral portion of the connecting surface near the injection hole. For this reason, in the technology disclosed herein, protrusions may be provided only in positions where a large amount of resin penetrates. Even with this configuration, it is possible to prevent resin from adhering to the center of the connection surface. Furthermore, protrusions do not need to be provided in areas where the resin R penetrates but does not reach the connection surface.

[0038] In this embodiment, a recess 24e into which the protrusion M1a of the mold M fits is formed on the peripheral edge 24a1 of the connection surface 24a of the electrode terminal 20. This configuration reliably prevents damage to the electrode terminal 20 and deformation of the mold M. Specifically, in the technology disclosed herein, the protrusion of the mold is inserted into the peripheral edge of the connection surface of the electrode terminal. This allows the protrusion to block resin flowing toward the center of the connection surface. However, if the peripheral edge of the connection surface into which the protrusion is inserted is flat, the protrusion of the mold must press and deform the peripheral edge of the connection surface. This may result in damage to the electrode terminal or deformation of the mold. In contrast, if the recess 24e is formed in advance on the peripheral edge 24a1 of the connection surface 24a of the electrode terminal 20, it is not necessary to press and deform the connection surface 24a with the protrusion M1a of the mold M, thereby preventing damage to the electrode terminal 20 and deformation of the mold M.

[0039] Furthermore, the protrusions M1a in this embodiment are tapered protrusions whose cross-sectional area decreases toward the tip. This tapered protrusion M1a can more effectively prevent the resin R from infiltrating into the central portion 24a2 of the connection surface 24a. Specifically, because the tapered protrusions M1a have sharp tips, they can be easily fitted into the recesses 24e on the connection surface 24a of the electrode terminal 20. This prevents the resin R from infiltrating due to poor fitting. Furthermore, in an embodiment in which the peripheral portion of the connection surface is press-deformed by the protrusions of a mold, stress is concentrated at the tip of the tapered protrusions, making it easier to press-deform the connection surface of the electrode terminal.

[0040] As the taper angle θ of the protrusion M1a increases, the strength of the protrusion M1a tends to improve. On the other hand, as the taper angle θ of the protrusion M1a decreases, it becomes easier for the protrusion M1a to penetrate into the peripheral portion 24a1 of the connection surface 24a of the electrode terminal 20. Considering this trade-off relationship, the taper angle θ of the tip of the protrusion M1a is preferably in the range of 30° to 90°.

[0041] Furthermore, when the recess 24e is formed in advance in the peripheral portion 24a1 of the connection surface 24a of the electrode terminal 20 as in this embodiment, the side surface 24e1 of the recess 24e is preferably inclined so as to be in surface contact with the inclined surface M1b of the tapered protrusion M1a. Specifically, the inclination angle of the side surface 24e1 of the recess 24e is preferably within a range of ±1° of the inclination angle of the inclined surface M1b of the protrusion M1a. With this configuration, even if the insertion position of the protrusion M1a relative to the recess 24e is slightly misaligned, the side surface 24e1 of the recess 24e can be in surface contact with the inclined surface M1b of the protrusion M1a. This prevents the resin from penetrating into the central portion 24a2 of the connection surface 24a, even if the insertion position is misaligned in the accommodation step S30.

[0042] Furthermore, it is preferable that a roughened surface portion Rs be formed on the surfaces of the sealing plate 14 and the electrode terminal 20 that come into contact with the resin R. This improves adhesion to the sealant 30 after curing. For example, as shown in FIGS. 2 to 4, the roughened surface portion Rs is formed on the outer surface 14b of the sealing plate 14 around the through-hole 14a, the side surface 24c of the plate portion 24, the upper end 22a of the shaft portion 22, and the like. Although not shown, the roughened surface portion Rs is also formed on the inner surface 14c of the sealing plate 14 around the through-hole 14a and the back surface 24b of the plate portion 24, and the like. The roughened surface portion Rs can be formed by a conventionally known roughening treatment (sandblasting, chemical treatment, etc.). Among these, if the roughened surface portion Rs is formed on the side surface 24c of the plate portion 24, the flow rate of the resin R in the resin flow path Mc3 decreases. This makes it more difficult for the resin R to reach the end Mc3a of the resin flow path Mc3. Therefore, from the viewpoint of suppressing adhesion of the resin R to the connecting surface 24a of the plate portion 24, it is particularly preferable that the roughened surface Rs be formed on the side surface 24c of the plate portion 24.

[0043] 2. Energy storage devices Next, an electricity storage device manufactured by the above-mentioned manufacturing method will be described. Fig. 8 is a perspective view schematically showing the electricity storage device according to the first embodiment. Fig. 9 is an enlarged cross-sectional view schematically showing the structure of the electricity storage device shown in Fig. 8 near an electrode terminal.

[0044] As shown in Figures 8 and 9, the electricity storage device 100 according to this embodiment includes an electrode assembly 40 and a case 10 that houses the electrode assembly 40. Although not shown, an electrolyte solution is also housed inside the case 10. The electrode assembly 40 and the electrolyte solution are power generation elements of the electricity storage device 100. These power generation elements can be any elements that can be used in conventionally known electricity storage devices without any particular restrictions, and therefore detailed description thereof will be omitted.

[0045] The case 10 is a flat, box-shaped container having an internal space. The case 10 in this embodiment includes a case main body 12 and a sealing plate 14. The case main body 12 is a box-shaped body having a top opening 12a. Specifically, the case main body 12 includes a bottom 12b, which is a long, rectangular plate-shaped member, a pair of first side walls 12c extending upward U from long sides (sides along the width direction X) of the bottom 12b, and a pair of second side walls 12d extending upward U from short sides (sides along the depth direction Y) of the bottom 12b. The top surface of the case main body 12 is formed with a top opening 12a surrounded by the upper ends of the first side wall 12c and the second side wall 12d. Meanwhile, the sealing plate 14 is a rectangular plate-shaped member that closes the top opening 12a of the case main body 12. Specifically, as shown in FIG. 2 , the sealing plate 14 is fitted into the upper end of the case main body 12. The boundary between case body 12 and sealing plate 14 is joined by laser welding or the like. Case 10 (case body 12 and sealing plate 14) is preferably a metal member having a certain level of strength or higher. Examples of materials for case 10 include metal materials such as aluminum and aluminum alloys.

[0046] As described above, in the electricity storage device 100 according to this embodiment, the case component for attaching the electrode terminal 20 and the sealing material 30 is the sealing plate 14. That is, the case 10 according to this embodiment includes a case component (sealing plate 14) having a through hole 14a, the electrode terminal 20 inserted into the through hole 14a, and the sealing material 30, which is a resin member that seals the through hole 14a and is integrated with the case component (sealing plate 14). In this specification, "integrated" refers to a state in which a metal member (such as a sealing plate or an electrode terminal) and a resin member (such as a sealing material) are fixed together.

[0047] The electrode terminal 20 has a shaft portion 22 inserted into the through-hole 14a of the sealing plate 14 and a plate portion 24 arranged along the case component (sealing plate 14). The plate portion 24 has a connection surface 24a exposed to the outside of the case 10, a back surface 24b opposite the connection surface 24a, and a side surface 24c continuous with the connection surface 24a and the back surface 24b. In an electricity storage device 100 having an electrode terminal 20 configured as described above, the shaft portion 22 and the electrode body 40 are connected inside the case 10. Meanwhile, an external conductive component (not shown), such as a bus bar, is connected to the connection surface 24a of the plate portion 24. This makes it easy to form a conductive path from the electrode body 40 to the external conductive component.

[0048] Furthermore, in the electricity storage device 100 according to this embodiment, a recess 24e recessed from the connection surface 24a is formed on a peripheral portion 24a1 of the connection surface 24a. This recess 24e may be formed in advance before the accommodation step S30, or may be generated when the connection surface 24a is pressed and deformed by the protrusion M1a of the mold M. Note that the electrode terminal 20 having this recess 24e has an advantage that the boundary between the resin and the metal on the upper surface of the electrode terminal 20 is clear, allowing for more accurate determination of the terminal position during image inspection of the electricity storage device 100 after manufacture.

[0049] Meanwhile, the sealing material 30 includes a side surface protective portion 36 that covers the side surface 24c of the plate portion 24. This side surface protective portion 36 can prevent electrical conduction between the plate portion 24 and the case 10 (sealing plate 14). Specifically, if the side surface 24c of the plate portion 24 is exposed, there is a risk that electrical conduction will occur between the electrode terminal 20 and the case 10 when conductive foreign matter (metal powder, liquid, etc.) adheres to the side surface 24c. The side surface protective portion 36 can prevent electrical conduction between the plate portion 24 and the case 10 via such conductive foreign matter. This side surface protective portion 36 is formed by filling the resin flow path Mc3 with resin R (see FIGS. 6 and 7).

[0050] Furthermore, in this embodiment, the sealing material 30 includes, in addition to the side surface protection portion 36 described above, a base portion 32, an internal insulating portion 34, and an external insulating portion 38. The base portion 32 is a portion that fills the through hole 14a of the sealing plate 14. The base portion 32 is a resin member that contacts the back surface 24b of the plate portion 24, the outer side surface of the through hole 14a, and the upper end portion 22a of the stem portion 22 (see FIG. 4). The base portion 32 serves as a base material that secures the electrode terminal 20 and the sealing plate 14 in an insulated state. The internal insulating portion 34 is a resin member that extends along the inner side surface 14c of the sealing plate 14. The internal insulating portion 34 insulates the stem portion 22 from the sealing plate 14. The internal insulating portion 34 also functions to prevent contact between the sealing plate 14 and the electrode body 40 when the electrode body 40 moves up and down due to vibration, etc. Furthermore, the external insulating portion 38 is a resin member that extends along the outer surface 14b of the sealing plate 14. By providing this external insulating portion 38, not only the side surface 24c of the plate portion 24 but also the outer surface 14b of the sealing plate 14 can be covered with an insulating member. This makes it possible to more effectively prevent conduction between the electrode terminal 20 and the sealing plate 14 via conductive foreign matter.

[0051] One embodiment of the technology disclosed herein has been described above. However, the technology disclosed herein is not limited to the above-described embodiment. Other embodiments of the technology disclosed herein will be described below.

[0052] <Second embodiment> For example, the mold M in the first embodiment has a tapered protrusion M1a (see FIG. 7). However, the cross-sectional shape of the protrusion is not particularly limited, and various shapes such as rectangular or semicircular can be employed. For example, FIG. 10 is an enlarged cross-sectional view schematically illustrating the injection step of the manufacturing method according to the second embodiment. The mold M shown in FIG. 10 has a protrusion M1a with a semicircular cross-section formed on the first surface M1. This semicircular protrusion M1a has superior strength compared to the tapered protrusion M1a shown in FIG. 7, and therefore can suppress deformation and breakage of the mold. However, this semicircular protrusion M1a makes it difficult to block the intrusion of the resin R when the insertion position with respect to the recess 24e is misaligned. Therefore, from the viewpoint of reliably preventing the resin R from adhering to the central portion 24a2 of the connection surface 24a, it is preferable to form the tapered protrusion M1a shown in FIG. 7.

[0053] <Other embodiments> 7 and 10, the mold M in the first and second embodiments has a first surface M1 that is in surface contact with the entire connecting surface 24a. However, the first surface of the mold may be in contact only with the peripheral edge of the connecting surface. As described above, according to the technology disclosed herein, the resin flowing toward the center of the connecting surface can be blocked by the convex portion, so that adhesion of the resin to the center of the connecting surface can be suppressed even if the center of the connecting surface and the first surface are not in surface contact. However, from the viewpoint of more reliably suppressing adhesion of the resin to the center of the connecting surface, it is preferable to have the entire connecting surface and the first surface of the mold in surface contact, as in the first and second embodiments.

[0054] The technology disclosed herein has been described in detail above. However, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. In other words, the technology disclosed herein encompasses the aspects described in items 1 to 7 below.

[0055] [Item 1] providing a case part having a through hole; inserting an electrode terminal into the through hole; placing the case part and the electrode terminal in an internal cavity of a mold; a step of injecting a resin into the internal cavity of the mold to integrally mold the case part and a sealing material that seals the through hole; Including, The electrode terminal is a shaft portion to be inserted into the through hole; a plate portion that is disposed along the case part when the shaft portion is inserted into the through hole; and The plate portion is a connection surface exposed to the outside of the case part; a back surface opposite to the connection surface; a side surface continuous with the connecting surface and the rear surface; Equipped with The mold is a first surface that is a cavity surface that is in surface contact with at least a peripheral portion of the connection surface of the plate portion; a third surface that is a cavity surface that faces the side surface of the plate portion with a gap therebetween; a protrusion protruding from the first surface toward the peripheral edge of the connecting surface; It is equipped with a method for manufacturing an electricity storage device, wherein in the integral molding step, the amount of resin injected into the internal cavity is controlled so that the resin that reaches the gap between the peripheral edge of the connection surface and the first surface via a resin flow path between the side surface and the third surface is blocked by the convex portion.

[0056] [Item 2] 2. The method for manufacturing an electricity storage device according to item 1, wherein the protrusion is formed on the first surface of the mold so as to be continuous along the periphery of the connection surface.

[0057] [Item 3] 3. The method for manufacturing an electricity storage device according to item 1 or 2, wherein a recess into which the protrusion of the mold fits is formed on the periphery of the connection surface.

[0058] [Item 4] 4. The method for manufacturing an electricity storage device according to any one of items 1 to 3, wherein the protrusions are tapered protrusions whose cross-sectional area decreases toward the tip.

[0059] [Item 5] 5. The method for manufacturing an electricity storage device according to any one of items 1 to 4, wherein a recess into which the protrusion of the mold fits is formed in a peripheral portion of the connection surface, and a side surface of the recess is inclined so as to be in surface contact with an inclined surface of the tapered protrusion.

[0060] [Item 6] 6. The method for manufacturing an electricity storage device according to any one of items 1 to 5, wherein the first surface of the mold is a flat surface that comes into surface contact with the entire surface of the connecting surface of the plate portion.

[0061] [Item 7] An electrode body; a case for accommodating the electrode assembly; Equipped with The case is a case part having a through hole; an electrode terminal inserted into the through hole; a sealing material that is a resin member that seals the through hole and is integrated with the case part; Including, The electrode terminal is a shaft portion inserted into the through hole; a plate portion disposed along the case part; and The plate portion is a connection surface exposed to the outside of the case; a back surface opposite to the connection surface; a side surface continuous with the connecting surface and the rear surface; Equipped with the sealing material includes a side surface protection portion that covers the side surface of the plate portion, The power storage device has a recess formed on the periphery of the connection surface, the recess being recessed from the connection surface. [Explanation of symbols]

[0062] 10: Case 12: Case body 14: Sealing plate 20: Electrode terminal 22: Shaft 24: Board part 24a: Connection surface 24e: Recess 30: Sealing material 32: Base part 34: Internal insulation 36: Side protection part 38: Outer insulation 40: Electrode body 100: Energy storage device M: Mold M1: Side 1 M1a: Convex part M2: 2nd side M3: 3rd side

Claims

1. providing a case part having a through hole; inserting an electrode terminal into the through hole; placing the case part and the electrode terminal in an internal cavity of a mold; a step of injecting a resin into the internal cavity of the mold to integrally mold the case part and a sealing material that seals the through hole; Including, The electrode terminal is a shaft portion to be inserted into the through hole; a plate portion that is disposed along the case part when the shaft portion is inserted into the through hole; and The plate portion is a connection surface exposed to the outside of the case part; a back surface opposite to the connection surface; a side surface continuous with the connecting surface and the rear surface; Equipped with The mold is a first surface that is a cavity surface that is in surface contact with at least a peripheral portion of the connection surface of the plate portion; a third surface that is a cavity surface that faces the side surface of the plate portion with a gap therebetween; a protrusion protruding from the first surface toward a peripheral edge of the connecting surface; It is equipped with A method for manufacturing an electricity storage device, wherein in the integral molding process, the amount of resin injected into the internal cavity is controlled so that the resin that reaches between the peripheral portion of the connection surface and the first surface via a resin flow path between the side surface and the third surface is blocked by the convex portion.

2. The method for manufacturing an electricity storage device according to claim 1 , wherein the protrusions are annular protrusions that are continuously provided in a circumferential direction so as to face each other around the entire periphery of the connecting surface.

3. The method for manufacturing an electricity storage device according to claim 1 , wherein a recess into which the protrusion of the mold fits is formed in a peripheral portion of the connection surface.

4. The method for manufacturing an electricity storage device according to claim 1 , wherein the protrusions are tapered protrusions whose cross-sectional area decreases toward their tips.

5. 2. The method for manufacturing an electricity storage device according to claim 1, wherein a recess into which the protrusion of the mold fits is formed on the peripheral portion of the connection surface, and the side of the recess is inclined so as to be in surface contact with the inclined surface of the tapered protrusion.

6. The method for manufacturing an electricity storage device according to claim 1 , wherein the first surface of the mold is a flat surface that comes into surface contact with the entire surface of the connecting surface of the plate portion.

7. An electrode body; a case for accommodating the electrode assembly; Equipped with The case is a case part having a through hole; an electrode terminal inserted into the through hole; a sealing material that is a resin member that seals the through hole and is integrated with the case part; Including, The electrode terminal is a shaft portion inserted into the through hole; a plate portion disposed along the case part; and The plate portion is a connection surface exposed to the outside of the case; a back surface opposite to the connection surface; a side surface continuous with the connecting surface and the rear surface; Equipped with the sealing material includes a side surface protection portion that covers the side surface of the plate portion, The power storage device has a recess formed on the periphery of the connection surface, the recess being recessed from the connection surface.

Images