Method for manufacturing energy storage device

Abstract

To prevent resin from adhering to a connection surface of an electrode terminal.SOLUTION: The manufacturing method disclosed herein comprises the steps of: preparing a case part having a through hole; inserting an electrode terminal into the through hole; placing the case part and the electrode terminal 20 within an internal cavity of a mold M; and injecting resin R into the internal cavity of the mold M. The electrode terminal 20 has a shaft portion 22 and a plate portion 24. The plate portion 24 includes a connection surface 24a, a back surface 24b, and a side surface 24c. The mold M includes a first surface M1 that is in surface contact with the connection surface 24a of the plate portion 24, a second surface M2 that is spaced apart from and faces the back surface 24b of the plate portion 24, and an injection hole Ms formed in the second surface M2 so as to face the back surface 24b of the plate portion 24. An injection amount of the resin R is controlled so that the resin R injected from the injection hole Ms presses the connection surface 24a against the first surface M1. This prevents the resin R from adhering to the connection surface 24a.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing 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] Incidentally, in order to connect to external conductive parts such as bus bars, electrode terminals must have connection surfaces that are exposed to the outside when attached to a case. 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 connection surfaces of the electrode terminals. In this case, processing is required to remove the resin adhered to the connection surfaces, 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] A 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 to be inserted into the through hole and a plate portion that is disposed along the case component when the shaft portion is inserted into the through hole. The plate portion has a connection surface exposed to the outside of the case component, a back surface opposite the connection surface, and a side surface 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 second surface that is a cavity surface facing the back surface of the plate portion at a distance, a third surface that is a cavity surface facing the side surface of the plate portion at a distance, and an injection hole that is an opening that penetrates the mold and is formed in the second surface so as to face the back surface of the plate portion. In the manufacturing method disclosed herein, in the integral molding step, resin is injected from the injection hole toward the rear surface of the plate 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 the resin will infiltrate into the gap between the first surface and the connection surface through the resin flow path. In contrast, in the manufacturing method disclosed herein, a resin injection hole is provided facing the back surface of the plate portion. With this configuration, the pressure of the resin injected from the injection hole presses the plate portion of the electrode terminal against the first surface of the mold. This eliminates the gap between the first surface and the connection surface, preventing the resin from adhering to the connection surface. As a result, the frequency of the process of removing resin adhering to 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 a perspective view schematically showing the electricity accumulation device according to the first embodiment. [Figure 8] FIG. 8 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 9] FIG. 9 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. 7 (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 8, the shaft portion 22 in this embodiment is an elongated plate-like member extending 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. 8). 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. 8 (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 U 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. 8 are properly formed, so that the components can be fixed more stably.

[0020] (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. 2) 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.

[0021] 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.

[0022] (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 connection surface 24a of the plate portion 24. By bringing the peripheral edge 24a1 of the connection surface 24a into surface contact with the first surface M1 in this manner, it is possible to prevent resin from penetrating between the connection surface 24a and the first surface M1. In this embodiment, the first surface M1 is a flat surface that is in surface contact with the entire connection 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 connection surface 24a but also with the central portion 24a2 of the connection surface 24a. This more effectively prevents resin from adhering to the connection surface 24a. In this specification, the area where the connection surface 24a and the first surface M1 are in surface contact is referred to as the "resin blocking portion Mc0."

[0023] 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.

[0024] (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. In the manufacturing method according to this embodiment, an injection hole Ms for injecting resin is formed in the second surface M2 of the mold M. Therefore, the space between the second surface M2 and the back surface 24b becomes the space into which the resin is first injected in the injection step S40. In the following description, this space will be referred to as the "first filling space Mc1." The resin filled in this first filling space Mc1 becomes the base portion 32 of the sealing material 30 (see FIG. 8).

[0025] 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. 8). 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.

[0026] The injection hole Ms is an opening that penetrates the mold M. In this embodiment, the injection hole Ms is formed in the second surface M2 so as to face the back surface 24b of the plate portion 24. Specifically, one end of the injection hole Ms is open to the interior of the mold M (first filling space Mc1), and the other end is open to the exterior of the mold M. The other end of the injection hole Ms is connected to a resin supply source (not shown) via a transfer pipe P. Resin R supplied from the resin supply source is injected into the internal cavity Mc (first filling space Mc1) of the mold M via the transfer pipe P and the injection hole Ms. At this time, the injection hole Ms faces the back surface 24b of the plate portion 24. Therefore, the resin R injected from the injection hole Ms presses the back surface 24b of the plate portion 24. As a result, the connecting surface 24a of the plate portion 24 is pressed against the first surface M1 of the mold M. In the manufacturing method according to this embodiment, this configuration prevents the resin from adhering to the connection surface 24a. Details of this configuration will be described later.

[0027] (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. 8). 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.

[0028] 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.

[0029] (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. 8). 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. Similar to 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.

[0030] (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. 8) 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.

[0031] The injection of resin R in this process will be described below. As described above, resin R is injected from the injection hole Ms into the internal cavity Mc. Then, resin R is first filled into the first filling space Mc1, which is the space with the largest volume. Then, resin R is supplied to the second filling space Mc2, resin flow path Mc3, fourth filling space Mc4, etc. via this first filling space Mc1. This prevents a large amount of resin R from being suddenly supplied to a relatively narrow space, thereby suppressing resin leakage and molding defects. In particular, supplying resin R to the resin flow path Mc3 via the first filling space Mc1 reduces the supply speed of resin R toward the tip Mc3a of the resin flow path Mc3. This more effectively suppresses intrusion of resin R into the resin blocking portion Mc0.

[0032] As described above, in this embodiment, the resin R is injected toward the back surface 24b of the plate portion 24 from the injection hole Ms facing the back surface 24b of the plate portion 24. This makes it possible to prevent the resin R from adhering to the connection surface 24a of the plate portion 24. This point will be explained in comparison with an embodiment that does not employ the technology disclosed herein. Figure 9 is a cross-sectional view that schematically shows the injection step of a manufacturing method that does not employ the technology disclosed herein.

[0033] The mold N shown in FIG. 9 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 area 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 will enter the resin blocking portion Nc0 through the tip Nc3a of the resin flow path Nc3. This causes resin to adhere to the connecting surface 124a of the plate portion 124, necessitating a process to remove the resin.

[0034] On the other hand, as shown in FIG. 6 , in this embodiment, an injection hole Ms is provided to face the back surface 24b of the plate portion 24. With this configuration, the pressure of the resin R injected from the injection hole Ms presses the plate portion 24 of the electrode terminal 20 against the first surface M1 of the mold M. As a result, even if a gap occurs between the connection surface 24a of the plate portion 24 and the first surface M1 of the mold M during the accommodation step S30, the gap can be eliminated early in the injection step S40. Furthermore, by the time the resin R reaches the tip Mc3a of the resin flow path Mc3, the resin blocking portion Mc0 is properly blocked. As a result, the resin R can be prevented from entering the resin blocking portion Mc0, and therefore, adhesion of the resin R to the connection surface 24a of the plate portion 24 can be suppressed. As described above, this embodiment 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.

[0035] Even if the injection hole Ms is provided facing the back surface 24b of the plate portion 24, if the amount of resin R injected from the injection hole Ms is small, the pressure pressing the plate portion 24 against the first surface M1 will be insufficient. In this case, the gap between the connecting surface 24a and the first surface M1 may not be eliminated by the time the resin R reaches the tip Mc3a of the resin flow path Mc3. For this reason, 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 injected from the injection hole Ms presses the connecting surface 24a of the plate portion 24 against the first surface M1. This appropriately prevents the resin R from adhering to the connecting surface 24a of the plate portion 24. The injection amount of resin R varies depending on the viscosity of the resin R, the distance from the injection hole Ms to the plate portion 24, and other factors, and is therefore not limited to a specific range. For example, after determining the dimensions of each part and the type of resin, a preliminary test can be conducted to examine the relationship between the amount of resin R attached to the connection surface 24a and the amount of resin R injected. Based on the results of this preliminary test, the appropriate amount of resin R to be injected can be determined.

[0036] Furthermore, in the injection step S40 of this embodiment, the resin R is injected toward the back surface 24b of the plate portion 24 along the thickness direction of the plate portion 24 (height direction Z in FIG. 6). This makes it easier for the injection pressure of the resin R to be transmitted to the plate portion 24, thereby increasing the force pressing the connecting surface 24a of the plate portion 24 against the first surface M1. As a result, the gap between the connecting surface 24a of the plate portion 24 and the first surface M1 of the mold M can be more appropriately eliminated. However, such a configuration is not essential to the technology disclosed herein. For example, even if the resin R is injected obliquely onto the plate portion 24, the gap between the connecting surface 24a and the first surface M1 can be sufficiently eliminated by controlling the injection amount of the resin R.

[0037] In this embodiment, the second surface M2 of the mold M is raised in a mountain-like shape toward the back surface 24b of the plate portion 24. The injection hole Ms is formed at the apex of the raised second surface M2. This allows the injection hole Ms of the mold M to be closer to the back surface 24b of the plate portion 24. As a result, the injection pressure of the resin R is more easily transmitted to the plate portion 24, more effectively eliminating the gap between the first surface M1 and the connecting surface 24a. Note that if the injection hole Ms is placed too close to the plate portion 24, it becomes difficult for the resin R to be supplied to the internal cavity Mc (such as the second filling space Mc2) above the injection hole Ms. In this case, molding defects of the sealing material 30 (see FIG. 8) may occur. For this reason, it is preferable to position the tip of the injection hole Ms between the outer surface 14b and the inner surface 14c of the case component (sealing plate 14) in the thickness direction (height direction Z). This makes it possible to appropriately eliminate the gap between the first surface M1 and the connecting surface 24a while suppressing molding defects of the sealing material 30. Note that this configuration is not essential to the technology disclosed herein. For example, even if the second surface of the mold is flat, the gap between the connecting surface 24a and the first surface M1 can be sufficiently eliminated by controlling the amount of resin R injected from the injection hole Ms.

[0038] Furthermore, the injection hole Ms in this embodiment faces the vicinity of the central portion 24b1 of the back surface 24b of the plate portion 24. This prevents variations in the pressure applied to the peripheral portion 24a1 of the connecting surface 24a of the plate portion 24. This prevents the occurrence of an area around the peripheral portion 24a1 of the connecting surface 24a into which the resin is likely to penetrate. Note that, in this specification, the "central portion of the plate portion" refers to a position that is half the dimension LT in the depth direction Y of the plate portion 24 (position 1 / 2LT). Furthermore, the "vicinity of the central portion of the plate portion" refers to a predetermined area that includes a position that is half the dimension LT. For example, the vicinity of the central portion of the plate portion refers to an area between 1 / 3LT and 2 / 3LT (preferably between 2 / 5LT and 4 / 5LT, and more preferably between 3 / 7LT and 4 / 7LT).

[0039] The injection pressure of the resin R in the injection step S40 is 500 kgf / cm 2 More than 550kgf / cm is preferable. 2 More preferably, 600kgf / cm2 More preferably, 650 kgf / cm 2 The above is particularly preferable. This makes it possible to more suitably eliminate the gap between the first surface M1 and the connection surface 24a. On the other hand, as the injection pressure of the resin R increases, the pressure of the resin R that tries to infiltrate into the resin blocking portion Mc0 via the tip Mc3a of the resin flow path Mc3 also increases. From this perspective, the injection pressure of the resin R is set to 1000 kgf / cm 2 Preferably less than 950kgf / cm 2 Less than 900kgf / cm is more preferable. 2 More preferably, 850 kgf / cm or less 2 The following are particularly preferred:

[0040] 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.

[0041] If a roughened surface Rs is formed on the surface that the injected resin R directly collides with (i.e., the back surface 24b of the plate portion 24), the roughened surface Rs may be damaged by the injection pressure of the resin R. For this reason, if a roughened surface Rs is formed on the back surface 24b of the plate portion 24, it is particularly preferable to control the injection pressure of the resin R to 1000 kgf / cm2 or less.

[0042] 2. Energy storage devices Next, an electricity storage device manufactured by the above-mentioned manufacturing method will be described. Fig. 7 is a perspective view schematically showing the electricity storage device according to the first embodiment. Fig. 8 is an enlarged cross-sectional view schematically showing the structure of the electricity storage device shown in Fig. 7 near an electrode terminal.

[0043] As shown in Figures 7 and 8, 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 suppress 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 if 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.

[0048] 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.

[0049] As described above, the manufacturing method according to this embodiment uses a mold M in which the second surface M2 is raised in a mountain-like shape toward the back surface 24b of the plate portion 24 (see FIG. 6). As a result, after manufacturing, a recess 39 is formed on the lower surface 32a of the base portion 32, recessed in a cone shape toward the upper U. This recess 39 recessed toward the upper U has the advantage that it can be used to position and fix a separate member (such as the shaft portion of the electrode terminal or the electrode body).

[0050] <Other embodiments> The above describes one embodiment of the technology disclosed herein. However, the technology disclosed herein is not limited to the above-described embodiment. For example, as shown in FIG. 6 , the mold M in the first and second embodiments includes 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 with only the peripheral edge of the connecting surface. As described above, the technology disclosed herein allows the electrode terminal to be pressed against the first surface of the mold by the resin injection pressure. This allows the peripheral edge of the connecting surface to be in surface contact with the first surface of the mold without any gaps. As a result, even if the central portion of the connecting surface is not in surface contact with the first surface, it is possible to prevent the resin from penetrating into the central portion of the connecting surface. However, from the perspective of more reliably suppressing adhesion of the resin to the central portion 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 above-described embodiment.

[0051] 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.

[0052] [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 second surface that is a cavity surface that faces the back surface of the plate portion with a gap therebetween; a third surface that is a cavity surface that faces the side surface of the plate portion with a gap therebetween; an injection hole which is an opening that penetrates the mold and is formed on the second surface so as to face the back surface of the plate portion; 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 injected from the injection hole presses the connection surface of the plate portion against the first surface.

[0053] [Item 2] 2. The method for manufacturing an electricity storage device according to item 1, wherein in the integral molding step, the resin is injected toward the rear surface of the plate portion along a thickness direction of the plate portion.

[0054] [Item 3] 3. The method for manufacturing an electricity storage device according to item 1 or 2, wherein the second surface is raised in a mountain-like shape toward the back surface of the plate portion, and the injection hole is formed at the apex of the raised second surface.

[0055] [Item 4] 4. The method for manufacturing an electricity storage device according to item 3, wherein a tip of the injection hole is disposed between an outer surface and an inner surface of the case part in a thickness direction.

[0056] [Item 5] 5. The method for manufacturing an electricity storage device according to any one of items 1 to 4, wherein the injection hole faces the vicinity of the center of the rear surface of the plate portion.

[0057] [Item 6] The injection pressure of the resin in the integral molding step is 500 kgf / cm2 More than 1000kgf / cm 2 6. A method for producing an electricity storage device according to any one of items 1 to 5, which is as follows:

[0058] [Item 7] 7. The method for manufacturing an electricity storage device according to any one of items 1 to 6, 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. [Explanation of symbols]

[0059] 10: Case 12: Case body 14: Sealing plate 20: Electrode terminal 22: Shaft 24: Board part 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 M2: 2nd side M3: 3rd side Ms: injection hole Mc: internal cavity Mc0: Resin blocking part Mc1: 1st filling space Mc2: 2nd filling space Mc3: Resin flow path Mc4: 4th filling space Mcs: Cavity surface

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 second surface that is a cavity surface that faces the back surface of the plate portion with a gap therebetween; a third surface that is a cavity surface that faces the side surface of the plate portion with a gap therebetween; an injection hole which is an opening that penetrates the mold and is formed on the second surface so as to face the back surface of the plate portion; 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 injected from the injection hole presses the connection surface of the plate portion against the first surface.

2. The method for manufacturing an electricity storage device according to claim 1 , wherein in the integral molding, the resin is injected toward the rear surface of the plate portion along a thickness direction of the plate portion.

3. The method for manufacturing an electricity storage device according to claim 1 , wherein the second surface is raised in a mountain-like shape toward the rear surface of the plate portion, and the injection hole is formed at an apex of the raised second surface.

4. The method for manufacturing an electricity storage device according to claim 3 , wherein a tip of the injection hole is disposed between an outer surface and an inner surface of the case part in a thickness direction.

5. The method for manufacturing an electricity storage device according to claim 1 , wherein the injection hole faces a vicinity of a center of the rear surface of the plate portion.

6. The injection pressure of the resin in the integral molding step is 500 kgf / cm ２ More than 1000kgf / cm ２ The method for manufacturing an electricity storage device according to claim 1 , wherein:

7. 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.

Images