Power storage device

Abstract

To keep the sealability around a current collecting terminal even if a case member is deformed.SOLUTION: A power storage device includes a current collecting terminal 30 including an external connection part 31, an electrode body connection part 32, and an annular sealing part 33 connected to the external connection part 31 and the electrode body connection part 32, and an insulating member 40 extending between the sealing part 33 and the case member 10 and into an annular part 33a of the sealing part 33. The annular part 33a of the sealing part 33 is formed by cutting a part of the inner periphery and bending another part. The sealing part 33 is disposed outside the case member 10, and the electrode body connection part 32 is formed at the bent part of the sealing part 33 and is inserted into the case member 10 from a terminal attachment hole 16. Alternatively, the sealing part 33 is disposed inside the case member 10 and the external connection part 31 is formed at the bent part of the sealing part 33 and extracted from the terminal attachment hole 16 to the outside of the case member 10.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device. [Background technology]

[0002] For example, Patent Document 1 discloses a sealed battery including a battery case with a terminal mounting hole, an electrode assembly housed inside the battery case, and a current collecting terminal. The current collecting terminal described in Patent Document 1 has an electrode assembly connection portion disposed inside the battery case and connected to the electrode assembly, an external connection portion disposed outside the battery case, and a shaft portion positioned between the electrode assembly connection portion and the external connection portion and inserted into the terminal mounting hole. The current collecting terminal is fixed to and insulated from the battery case by an insulating material integrally molded with the battery case and the current collecting terminal. The boundaries between the current collecting terminal and the insulating material, and between the battery case and the insulating material, are sealed in various locations. Patent Document 1 states that inserting the current collecting terminal into the terminal mounting hole of the battery case and molding the insulating material integrally with the battery case and the current collecting terminal makes it easier to remove the electrodes from a sealed battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-086813 Summary of the Invention [Problem to be solved by the invention]

[0004] In an electricity storage device in which an electrode body is housed in a case member, the case member may be deformed due to internal pressure of the case member, etc. If the case member is deformed, it becomes difficult to maintain a seal around the current collecting terminal. Here, we propose an electricity storage device with a simple configuration that makes it easy to maintain a seal around the current collecting terminal even when the case member is deformed. [Means for solving the problem]

[0005] The proposed electricity storage device includes a case member having a terminal mounting hole, an electrode assembly housed inside the case member, a current collecting terminal, and an insulating member. The current collecting terminal has an external connection portion located outside the case member, an electrode assembly connection portion located inside the case member and connected to the electrode assembly, and an annular seal portion located outside or inside the case member and connected to the external connection portion and the electrode assembly connection portion. The insulating member extends at least between the seal portion and the case member and inside the annular portion of the seal portion, sealing and insulating between the current collecting terminal and the case member. The annular portion of the seal portion is formed by cutting a portion of the inner circumference and bending another portion. The electricity storage device has the following configuration (A) or (B): (A) The seal portion is located outside the case member, and the electrode assembly connection portion is formed in the bent portion of the seal portion and inserted into the case member through the terminal mounting hole. (B) The sealing portion is disposed inside the case member, and the external connection portion is formed in the bent portion of the sealing portion and extends to the outside of the case member through the terminal mounting hole.

[0006] In the above-described electricity storage device, the insulating member is supported by the annular seal portion and is therefore less likely to move, even if the case member is deformed. Therefore, in the above-described electricity storage device, the sealing performance around the current collecting terminal is easily maintained even when the case member is deformed. Furthermore, in the above-described electricity storage device, the electrode assembly connection portion or the external connection portion is formed in the bent portion of the seal portion. Therefore, a current collecting terminal including an annular seal portion, an electrode assembly connection portion, and an external connection portion can be realized with a simple configuration. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a vertical cross-sectional view of an electricity storage device according to an embodiment. [Figure 2] FIG. 2 is a perspective view of a sealing plate and a current collecting terminal. [Figure 3] FIG. 2 is a perspective view of a sealing plate, a current collecting terminal, and an insulating member. [Figure 4] FIG. 2 is a vertical cross-sectional view of the vicinity of a current collecting terminal. [Figure 5] FIG. 1 is a schematic process diagram for manufacturing an electricity storage device. [Figure 6] FIG. 10 is a perspective view of a collector terminal according to a modified example. [Figure 7] FIG. 10 is a vertical cross-sectional view of the vicinity of a current collecting terminal according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of an electricity storage device will be described below. It should be noted that the embodiment described here is, of course, not intended to limit the present invention. Furthermore, each figure is a schematic diagram and does not necessarily faithfully reflect an actual product. Hereinafter, components and parts that perform the same function will be assigned the same reference numerals, and duplicated descriptions will be omitted or simplified as appropriate. In the drawings, front, rear, top, bottom, left, and right will be represented by F, Rr, U, D, L, and R, respectively. However, the terms front, rear, top, bottom, left, and right are merely used for the convenience of explanation and do not limit the installation mode of the electricity storage device.

[0009] In this specification, the term "energy storage device" refers to a general device that can extract electrical energy, and is a concept that includes primary batteries and secondary batteries, as well as chemical batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, and physical batteries such as electric double layer capacitors.

[0010] [Configuration of the energy storage device] Fig. 1 is a longitudinal cross-sectional view of an electricity storage device 100 according to one embodiment. As shown in Fig. 1, the electricity storage device 100 includes a battery case 10, an electrode assembly 20, positive and negative current collecting terminals 30, and a pair of insulating members 40 corresponding to the positive and negative current collecting terminals 30, respectively.

[0011] As shown in FIG. 1 , in this embodiment, the battery case 10 includes a case body 11 and a pair of sealing plates 15. Here, the case body 11 is a flat, rectangular container having a substantially rectangular parallelepiped shape. Openings 12 are formed in a pair of opposing narrow sides of the case body 11. The case body 11 is made of, for example, aluminum. In the description of this embodiment, the direction in which the pair of opposing wide sides of the case body 11 face is defined as the front-rear direction of the electricity storage device 100. The front-rear direction is the thickness direction of the electricity storage device 100. The up-down direction is the height direction of the electricity storage device 100. The left-right direction is the width direction of the electricity storage device 100, which is the longitudinal direction here.

[0012] The sealing plate 15 is a plate-shaped member that is attached to the opening 12 of the case body 11. The sealing plate 15 is welded to the periphery of the opening 12 of the case body 11. The sealing plate 15 is also formed of, for example, aluminum. The pair of sealing plates 15 here have the same configuration. The pair of sealing plates 15 each extend in the thickness direction and the height direction of the electricity storage device 100. The sealing plate 15 has an inner surface 15a facing the inside of the electricity storage device 100 and an outer surface 15b facing the outside. The sealing plate 15 also has a terminal mounting hole 16 that penetrates between the inner surface 15a and the outer surface 15b. The detailed configuration of the sealing plate 15 will be described later.

[0013] The electrode assembly 20 is housed inside the battery case 10, here, inside the case body 11. The electrode assembly 20 is housed in the case body 11 while covered, for example, with an insulating film (not shown). The electrode assembly 20 includes a plurality of positive electrode sheets 21, a plurality of negative electrode sheets 22, and a plurality of separator sheets 23. The positive electrode sheets 21 and the negative electrode sheets 22 are alternately stacked with the separator sheets 23 sandwiched between them. The plurality of separator sheets 23 are disposed between the positive electrode sheets 21 and the negative electrode sheets 22, and insulate the positive electrode sheets 21 from the negative electrode sheets 22. The plurality of positive electrode sheets 21, the plurality of negative electrode sheets 22, and the plurality of separator sheets 23 are stacked in the thickness direction of the electricity storage device 100.

[0014] The positive electrode sheet 21 is a member in which a positive electrode active material layer containing a positive electrode active material is formed on both sides of a metal foil (e.g., aluminum foil) of a predetermined width and thickness. In a lithium-ion secondary battery, the positive electrode active material is, for example, a material that can release lithium ions during charging and absorb lithium ions during discharging, such as a lithium transition metal composite material. Generally, various positive electrode active materials other than lithium transition metal composite materials have been proposed, and there is no particular limitation. Each positive electrode sheet 21 has a tab 21a connected to the positive electrode collector terminal 30. The tab 21a is located at one end of each positive electrode sheet 21 in the longitudinal direction of the electricity storage device 100, more specifically, at the end on the side where the positive electrode collector terminal 30 is provided.

[0015] The negative electrode sheet 22 is a member in which a negative electrode active material layer containing a negative electrode active material is formed on both sides of a metal foil (e.g., copper foil) of a predetermined width and thickness. In a lithium-ion secondary battery, the negative electrode active material is, for example, a material such as natural graphite that can absorb lithium ions during charging and release the absorbed lithium ions during discharging. Various negative electrode active materials other than natural graphite have generally been proposed, and there is no particular limitation. Each negative electrode sheet 22 has a tab 22a connected to the negative electrode collector terminal 30. The tab 22a is located on the other end of each negative electrode sheet 22 in the longitudinal direction of the electricity storage device 100, more specifically, on the end on the side where the negative electrode collector terminal 30 is provided.

[0016] For example, a porous resin sheet that has required heat resistance and allows electrolyte to pass through is used as the separator sheet 23. Various types of separator sheet 23 have been proposed, and there is no particular limitation.

[0017] The pair of current collector terminals 30 are each attached to the sealing plate 15. The positive electrode side current collector terminal 30 is connected to the tabs 21a of the multiple positive electrode sheets 21. The positive electrode side current collector terminal 30 is made of, for example, aluminum. The negative electrode side current collector terminal 30 is connected to the tabs 22a of the multiple negative electrode sheets 22. The negative electrode side current collector terminal 30 is made of, for example, copper. A portion of each of the pair of current collector terminals 30 is exposed to the outside of the battery case 10 so that the power generated by the electrode body 20 can be extracted to the outside. In this embodiment, the positive electrode side current collector terminal 30 and the negative electrode side current collector terminal 30 are arranged separately on the left and right. The detailed configuration of the current collector terminals 30 will be described later.

[0018] The insulating member 40 on the positive electrode side insulates and seals between the positive electrode side current collector terminal 30 and the battery case 10. The insulating member 40 on the negative electrode side insulates and seals between the negative electrode side current collector terminal 30 and the battery case 10. The detailed configuration of the pair of insulating members 40 will be described later.

[0019] [Configuration near the current collecting terminal] The configurations of the sealing plate 15, the current collecting terminal 30, and the insulating member 40 will be described in detail below. FIG. 2 is a perspective view of the sealing plate 15 and the current collecting terminal 30. FIG. 2 shows the sealing plate 15 and the current collecting terminal 30 in a separated state before assembly. FIG. 3 is a perspective view of the sealing plate 15, the current collecting terminal 30, and the insulating member 40. FIG. 3 shows the assembly of the sealing plate 15, the current collecting terminal 30, and the insulating member 40 in a state before assembly into the case body 11. FIG. 4 is a vertical cross-sectional view of the vicinity of the current collecting terminal 30.

[0020] As shown in FIG. 2, in this embodiment, the sealing plate 15 has a flat terminal mounting hole 16 whose length in the thickness direction (here, the front-to-rear direction) of the battery case 10 is longer than its length in the height direction (here, the up-and-down direction) of the battery case 10. A portion of the surface of the sealing plate 15 has been roughened. As shown in FIG. 4, here, the inner surface 15a of the sealing plate 15 is roughened around the terminal mounting hole 16 so as to surround the terminal mounting hole 16 (indicated by the symbol A1). Hereinafter, this roughened portion of the sealing plate 15 will also be referred to as the roughened region A1. The roughening process can be performed, for example, by laser irradiation, sandblasting, electrolytic etching, or the like.

[0021] The current collecting terminal 30 is formed by cutting and bending a flat plate-shaped member. As shown in Fig. 2, the current collecting terminal 30 has an external connection portion 31, an electrode assembly connection portion 32, and a seal portion 33.

[0022] The seal portion 33 is configured in an annular shape. The annular portion 33a of the seal portion 33 is formed by cutting a portion of the inner circumference and bending another portion. The electrode assembly connection portion 32 is formed in the bent portion of the seal portion 33. The seal portion 33 and the electrode assembly connection portion 32 are formed by a cutting and bending process. Here, the cut portion 33b used to form the annular portion 33a extends in the vertical direction along the front end of the current collecting terminal 30, then extends rearward from the lower end, and further extends upward along the rear end of the current collecting terminal 30. The cut portion 33b is formed in a C-shape.

[0023] The electrode assembly connection portion 32 is formed by bending the inner portion of the C-shaped cut portion 33b at the remaining side of a rectangle having three sides defined by the cut portion 33b. The electrode assembly connection portion 32 is formed by bending the inner portion of the cut portion 33b toward the interior of the battery case 10. Here, the electrode assembly connection portion 32 protrudes further toward the interior of the battery case 10 than the seal portion 33, and extends in the width and thickness directions of the battery case 10.

[0024] As shown in Figures 3 and 4, the sealing portion 33 is disposed outside the battery case 10. Here, the sealing portion 33 extends in the up-down and front-rear directions along the outer surface 15b of the sealing plate 15. However, as will be described later, the sealing portion 33 may also be disposed inside the battery case 10. As shown in Figure 4, the electrode assembly connecting portion 32 is inserted into the battery case 10 through the terminal mounting hole 16. The electrode assembly connecting portion 32 is disposed inside the battery case 10. The electrode assembly connecting portion 32 is connected to the electrode assembly 20 inside the battery case 10 (see Figure 1). The tip of the electrode assembly connecting portion 32 is bent downward.

[0025] As shown in Fig. 2, the seal portion 33 and the electrode assembly connection portion 32 are provided below the current collecting terminal 30. The external connection portion 31 is disposed above the seal portion 33. As shown in Figs. 3 and 4, the external connection portion 31 is disposed outside the battery case 10. Here, the external connection portion 31 extends in the up-down and front-rear directions along the outer surface 15b of the sealing plate 15.

[0026] A portion of the surface of the current collecting terminal 30 is roughened. In this embodiment, the roughening treatment is applied to the facing surface (inner surface) 33a1 of the annular portion 33a of the seal portion 33, which faces the battery case 10 (here, the sealing plate 15), and the back surface (outer surface) 33a2 of the facing surface 33a1. In FIGS. 2 and 4, the roughened portion is indicated by the symbol A2. Hereinafter, this roughened portion of the current collecting terminal 30 will also be referred to as the roughened region A2. Of the inner peripheral surface of the annular portion 33a, a surface 33b1 (cut surface of the cut portion 33b) formed by cutting is not roughened. However, the cut surface 33b1 of the cut portion 33b may also be roughened. In this embodiment, the other portions of the surface of the current collecting terminal 30 are not roughened, but may be roughened.

[0027] The insulating member 40 extends at least between the seal portion 33 and the battery case 10 and into the annular portion 33a of the seal portion 33, sealing and insulating the current collecting terminal 30 from the battery case 10. As shown in FIG. 4, the insulating member 40 extends inside the terminal mounting hole 16, around the terminal mounting hole 16 inside the battery case 10, between the battery case 10 (specifically, the sealing plate 15) and the seal portion 33, inside the annular portion 33a of the seal portion 33, between the battery case 10 (specifically, the sealing plate 15) and the external connection portion 31, and outside the seal portion 33. As shown in FIG. 3, the outside of the seal portion 33 refers to the periphery of the annular portion 33a (here, above, in front, below, and behind) and outward from the outer surface 33a2 of the seal portion 33 (to the right in FIG. 3). As shown in FIG. 3, the insulating member 40 is configured to cover the entire seal portion 33.

[0028] However, in a mode in which there is no risk of the external connection portion 31 coming into contact with the sealing plate 15, such as when the external connection portion 31 is bent so as to intersect with the sealing portion 33, the insulating member 40 does not have to extend between the sealing plate 15 and the external connection portion 31. Furthermore, the insulating member 40 may have a non-penetrating recess inside the annular portion 33a.

[0029] The insulating member 40 is formed by integral resin molding of the battery case 10 and the current collecting terminal 30. The insulating member 40 is made of a thermoplastic resin. As shown in FIG. 4 , the insulating member 40 is formed so as to cover the terminal mounting hole 16 of the battery case 10. In this way, the insulating member 40 is fixed to the battery case 10. The insulating member 40 is also formed so as to cover the annular portion 33a of the seal portion 33. In this way, the current collecting terminal 30 is fixed to the insulating member 40.

[0030] The insulating member 40 is firmly bonded to the roughened portion A1 of the battery case 10 and the roughened portion A2 of the current collecting terminal 30 by an anchor effect. The insulating member 40 seals the battery case 10 at least in the areas that contact the roughened portions A1 and A2. Specifically, the insulating member 40 provides sealing properties at least around the terminal mounting hole 16 (the roughened portion A1 of the battery case 10) and the inner surface 33a1 and outer surface 33a2 of the seal portion 33 (the roughened portion A2 of the current collecting terminal 30). Portions of the insulating member 40 that contact areas other than the roughened portion A1 of the battery case 10 and the roughened portion A2 of the current collecting terminal 30 may or may not have sealing properties. However, sealing properties are not necessarily required in these areas.

[0031] [Manufacturing process for energy storage devices] The manufacturing process of the electricity storage device 100 will be described below. FIG. 5 is a schematic diagram of the manufacturing process of the electricity storage device 100. As shown in FIG. 5, in step S01 of the manufacturing process of the current collecting terminal 30, a metal plate that is the material for the current collecting terminal 30 is cut to form a cut portion 33b. In step S02, the inner portion of the cut portion 33b is bent to form the electrode assembly connection portion 32 and the annular portion 33a of the seal portion 33. In step S03, a roughening process is performed on the inner surface 33a1 and the outer surface 33a2 of the seal portion 33. The roughening process is performed, for example, by laser irradiation. Because the cut surface 33b1 of the seal portion 33 is not roughened, the roughening process in step S03 does not require tilting the current collecting terminal 30 or the laser gun so that the laser hits the cut surface 33b1. This simplifies the roughening process.

[0032] In step S11 of the assembly process of the sealing plate 15 and the current collecting terminal 30, the periphery of the terminal mounting hole 16 of the sealing plate 15 is roughened. In step S12, the sealing plate 15 and the current collecting terminal 30 are set in a molding die. In step S13, molten resin is injected into the die to integrally mold the sealing plate 15, the current collecting terminal 30, and the insulating member 40 into a resin-molded unit. In step S14, the integrally molded product of the sealing plate 15, the current collecting terminal 30, and the insulating member 40 (hereinafter also referred to as the terminal assembly) is removed from the die (demolding). In step S15, the terminal assembly is inspected for airtightness.

[0033] In step S21 of the assembly process, the electrode body connection portion 32 of the positive electrode terminal assembly is welded to the positive electrode tab 21a of the electrode body 20, and the electrode body connection portion 32 of the negative electrode terminal assembly is welded to the negative electrode tab 22a. In step S22, the assembly of the electrode body 20 and the pair of terminal assemblies is attached to the case body 11. In step S23, the sealing plate 15 is welded to the opening 12 of the case body 11. In step S24, electrolyte is injected into the battery case 10 through an electrolyte injection port (not shown). In step S25, the electrolyte injection port is sealed. This completes the electricity storage device 100.

[0034] The above-described steps are only an outline of the process and are one example, and the manufacturing process of the electricity storage device 100 includes steps whose description has been omitted, such as the manufacturing process of the electrode body 20. The manufacturing process of the electricity storage device 100 may also include other steps that have not been described.

[0035] [Effects of the embodiment] The following describes the effects that can be achieved by the electricity storage device 100 according to this embodiment.

[0036] The electricity storage device 100 according to this embodiment includes a battery case 10 having a terminal mounting hole 16, an electrode assembly 20 housed inside the battery case 10, a current collecting terminal 30, and an insulating member 40. The current collecting terminal 30 has an external connection portion 31 disposed outside the battery case 10, an electrode assembly connection portion 32 disposed inside the battery case 10 and connected to the electrode assembly 20, and an annular seal portion 33 disposed outside the battery case 10 and connected to the external connection portion 31 and the electrode assembly connection portion 32. The insulating member 40 extends at least between the seal portion 33 and the battery case 10 and into the annular portion 33a of the seal portion 33, thereby sealing and insulating between the current collecting terminal 30 and the battery case 10. The annular portion 33a of the seal portion 33 is formed by cutting a portion of the inner circumference and bending another portion. The electrode assembly connection portion 32 is formed in the bent portion of the seal portion 33 and is inserted into the battery case 10 through the terminal mounting hole 16.

[0037] In this electricity storage device 100, even if the battery case 10 is deformed due to internal pressure, for example, the insulating member 40 is supported by the annular seal portion 33 and is therefore less likely to move. Therefore, in the electricity storage device 100 according to this embodiment, the sealing performance around the current collecting terminal 30 is easily maintained even when the battery case 10 is deformed. Furthermore, in the electricity storage device 100 according to this embodiment, the electrode assembly connection portion 32 is formed in the bent portion of the seal portion 33. Therefore, a current collecting terminal 30 including the external connection portion 31, the electrode assembly connection portion 32, and the annular seal portion 33 can be realized with a simple configuration.

[0038] In this embodiment, the insulating member 40 extends inside the terminal mounting hole 16, between the battery case 10 and the seal portion 33, inside the annular portion 33a of the seal portion 33, and outward from the seal portion 33. With this configuration, the insulating member 40 extends to cover the annular portion 33a of the current collecting terminal 30. This allows the insulating member 40 to be firmly fixed to the annular portion 33a. This increases the resistance of the insulating member 40 to deformation of the battery case 10 due to internal pressure, etc.

[0039] In this embodiment, the insulating member 40 is formed by integral resin molding with the battery case 10 and the current collecting terminal 30. This configuration makes it easy to form the insulating member 40 so that it covers the annular portion 33a of the current collecting terminal 30. Note that the insulating member 40 is not limited to being an integrally molded product, as long as it at least extends between the seal portion 33 and the battery case 10 and into the annular portion 33a of the seal portion 33. The insulating member 40 may include, for example, a packing or the like having sealing properties.

[0040] In this embodiment, the annular portion 33a of the seal portion 33 is roughened on the facing surface 33a1 facing the battery case 10 and on the back surface 33a2 of the facing surface 33a1. This configuration provides an anchor effect due to the roughening process, sealing the gap between the facing surface 33a1 and its back surface 33a2 and the insulating member 40, thereby ensuring reliable sealing of the battery case 10. The annular portion 33a of the seal portion 33 and the portion of the insulating member 40 joined thereto are less likely to move even when the battery case 10 deforms. This makes the joint less likely to peel, and the seal is more likely to be maintained. Furthermore, this configuration simplifies the roughening process because the roughened portion A2 of the current collecting terminal 30 is less likely to be roughened. Other portions of the current collecting terminal 30 may also be roughened, and other roughened portions may also be sealed.

[0041] In this embodiment, the surface 33b1 of the inner circumferential surface of the annular portion 33a, which is formed by cutting, is not roughened. With this configuration, the roughening process can be simplified by omitting the roughening process of the cut surface 33b1. Note that, because the roughening process does not need to be performed on the cut surface 33b1, the roughening process can be performed before the cutting and bending process for forming the electrode assembly connection portion 32 and the seal portion 33. Therefore, with this configuration, the flexibility of the process is improved.

[0042] [Other embodiments] Although one embodiment of the proposed power storage device has been described above, the above embodiment is merely an example and the device may be embodied in other ways.

[0043] For example, the shape of the electrode assembly connection part 32 can be modified in various ways depending on the overall configuration of the electricity storage device 100. Fig. 6 is a perspective view of a current collecting terminal 30 according to one modification. As shown in Fig. 6, the electrode assembly connection part 32 may be formed so as to extend in the direction in which the external connection part 31 and the seal part 33 are aligned (the up-and-down direction in Fig. 6). The shape of the electrode assembly connection part 32 is not limited to a rectangular shape. The electrode assembly connection part 32 may have, for example, a hook shape or another shape.

[0044] Furthermore, for example, the seal portion 33 may be disposed inside the battery case 10. Fig. 7 is a vertical cross-sectional view of the vicinity of the current collecting terminal 30 according to another modification. As shown in Fig. 7, according to one modification, the seal portion 33 is disposed inside the battery case 10. In such a case, the external connection portion 31 is formed in the bent portion of the seal portion 33 and extends to the outside of the battery case 10 through the terminal mounting hole 16. Even with this configuration, it is possible to achieve the same effects as those of the first embodiment.

[0045] Furthermore, according to the configuration of the first embodiment in which the sealing portion 33 is arranged outside the battery case 10, the occupancy rate of the electrode body 20 within the battery case 10 can be increased, and the amount of energy per volume of the electricity storage device 100 can be increased.

[0046] The configuration of the electricity storage device 100 other than the current collecting terminals 30 is not particularly limited. For example, in the above-described embodiment, the electricity storage device 100 has the positive electrode current collecting terminal 30 and the negative electrode current collecting terminal 30 arranged separately on both sides in the longitudinal direction. However, the positive electrode and negative electrode current collecting terminals 30 may be provided on a single sealing plate 15.

[0047] The above-described embodiments do not limit the present invention unless otherwise specified. Furthermore, the technology disclosed herein can be modified in various ways. The components and processes described herein can be omitted or combined as appropriate, provided that no particular problems arise. This specification includes the disclosures described in the following sections.

[0048] Section 1: a case member having a terminal mounting hole; an electrode body housed inside the case member; a current collecting terminal having an external connection portion disposed outside the case member, an electrode body connection portion disposed inside the case member and connected to the electrode body, and an annular seal portion disposed outside or inside the case member and connected to the external connection portion and the electrode body connection portion; an insulating member that extends at least between the seal portion and the case member and inside the annular portion of the seal portion, and that seals and insulates between the current collecting terminal and the case member, the annular portion of the sealing portion is formed by cutting a part of an inner periphery and bending another part, (A) the seal portion is disposed outside the case member, and the electrode body connection portion is formed in a bent portion of the seal portion and inserted into the case member through the terminal mounting hole, or (B) the sealing portion is disposed inside the case member, and the external connection portion is formed in a bent portion of the sealing portion and is taken out to the outside of the case member through the terminal mounting hole; Energy storage device.

[0049] Section 2: The insulating member extends inside the terminal mounting hole, between the case member and the seal portion, inside the annular portion of the seal portion, and outside the seal portion. Item 1. The electricity storage device according to item 1.

[0050] Section 3: the insulating member is formed by integral resin molding together with the case member and the current collecting terminal; Item 3. The electricity storage device according to item 2.

[0051] Section 4: a surface of the annular portion facing the case member and a back surface of the facing surface are roughened; Item 4. The electricity storage device according to item 3.

[0052] Section 5: The inner peripheral surface of the annular portion formed by cutting is not subjected to a roughening treatment. Item 5. The electricity storage device according to item 4. [Explanation of symbols]

[0053] 10 Battery case (case material) 11 Case body 12 Opening 15 Sealing plate 15a Inside surface 15b External surface 16 Terminal mounting hole 20 Electrode body 21 Positive electrode sheet 21a Positive electrode tab 22 Negative electrode sheet 22a Negative electrode tab 23 Separator sheet 30 Current collector terminal 31 External connection part 32 Electrode body connection part 33 Seal part 33a Annular part 33a1 Opposing surface (inner surface) 33a2 Back side (outer side) 33b Cut section 33b1 Cut surface 40 Insulating material 100 Energy storage device A1 Roughened area of ​​the sealing plate A2 Roughened area of ​​collector terminal

Claims

1. a case member having a terminal mounting hole; an electrode body housed inside the case member; a current collecting terminal having an external connection portion disposed outside the case member, an electrode body connection portion disposed inside the case member and connected to the electrode body, and an annular seal portion disposed outside or inside the case member and connected to the external connection portion and the electrode body connection portion; an insulating member that extends at least between the seal portion and the case member and inside the annular portion of the seal portion, and that seals and insulates between the current collecting terminal and the case member, the annular portion of the sealing portion is formed by cutting a part of an inner periphery and bending another part, (A) The seal portion is disposed outside the case member, and the electrode body connection portion is formed in a bent portion of the seal portion and inserted into the case member through the terminal mounting hole, or (B) the seal portion is disposed inside the case member, and the external connection portion is formed in a bent portion of the seal portion and is taken out to the outside of the case member through the terminal mounting hole. Energy storage device.

2. The insulating member extends inside the terminal mounting hole, between the case member and the seal portion, inside the annular portion of the seal portion, and outside the seal portion. The electricity storage device according to claim 1 .

3. the insulating member is formed by integral resin molding together with the case member and the current collecting terminal; The electricity storage device according to claim 2 .

4. a surface of the annular portion facing the case member and a back surface of the facing surface are roughened; The electricity storage device according to claim 3 .

5. The inner peripheral surface of the annular portion formed by cutting is not subjected to a roughening treatment. The electricity storage device according to claim 4 .

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