Power storage device and power storage unit

Abstract

To increase load efficiency of a power storage device in an electronic product.SOLUTION: A power storage device 1 includes an electrode body 10, a case 20, an insulation member 30, and a collector 40. The collector 40 includes a terminal part 44 that is arranged to block a terminal mounting hole 25 via the insulation member 30, joined to the insulation member 30, exposed outside of the case 20 through the terminal mounting hole 25, and electrically connectable to an external member. The terminal part 44 is arranged further inward than an outer face 20a of the case 20. The terminal mounting hole 25 is sealed by the insulation member 30 and the collector 40. Such a configuration increases load efficiency in an electronic product since both of formation of a conductive pathway to the outside of the case 20 and sealing of the inside of the case 20 are achieved without installation of an electrode terminal protruding outside the case 20.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an electricity storage device and an electricity storage unit. [Background technology]

[0002] Electricity storage devices such as lithium ion secondary batteries are used as power sources for various electrical products. An example of this electricity storage device (sealed battery) is disclosed in Patent Document 1 (JP 2021-86813 A). The electricity storage device described in Patent Document 1 includes a case member having a terminal mounting hole, an electrode body housed inside the case member, a current collecting terminal, and an insulating material. The current collecting terminal has an electrode body connection part disposed inside the case member and connected to the electrode body, an external connection part disposed outside the case member, and an axis part located between the electrode body connection part and the external connection part and inserted into the terminal mounting hole. At least one of the electrode body connection part and the external connection part is configured to have a size that can be inserted into the terminal mounting hole. The insulating material is integrally molded with the case member and the current collecting terminal so as to fill the gap between the terminal mounting hole and the current collecting terminal. The electricity storage device described in Patent Document 1 is said to be able to more easily take out the electrodes to the outside. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-86813 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Document 1, in a typical electricity storage device, a part of the current collecting terminal (external connection part) protrudes outside the case. On the other hand, the loading space for the electricity storage device in the electrical appliance is limited. Therefore, the external connection part protruding outside the case is a factor that reduces the loading efficiency of the electricity storage device in the electrical appliance. [Means for solving the problem]

[0005] In response to the above-mentioned problems, an electricity storage device having the following configuration is provided.

[0006] The electric storage device disclosed herein includes an electrode body, a case that houses the electrode body and has a terminal mounting hole, an insulating material that covers the peripheral wall and the peripheral portion of the terminal mounting hole continuously in the circumferential direction and is joined to the peripheral portion of the terminal mounting hole, and a current collector that is electrically connected to the electrode body inside the case. The current collector is disposed so as to close the terminal mounting hole via the insulating material and is joined to the insulating material. The current collector has a terminal portion that is exposed to the outside of the case through the terminal mounting hole and can be electrically connected to an external member. In the electric storage device disclosed herein, the terminal portion is located inside the outer surface of the case, and the terminal mounting hole is sealed by the insulating material and the current collector.

[0007] In the electricity storage device having the above configuration, a part (terminal portion) of the current collector housed in the case is exposed to the outside of the case through the terminal mounting hole. The upper surface of this terminal portion is located inside the outer surface of the case. The terminal mounting hole of the case is sealed by an insulating material and the terminal portion. With this configuration, it is possible to form a conductive path to the outside of the case and to seal the inside of the case without providing an electrode terminal (external connection member) that protrudes outside the case. Therefore, the electricity storage device disclosed herein can contribute to improving the loading efficiency of electrical products. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view that illustrates a schematic diagram of an electricity accumulation device according to a first embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view that illustrates a schematic structure of the vicinity of a terminal mounting hole of the electricity accumulation device according to the first embodiment. [Diagram 3] FIG. 3 is an enlarged cross-sectional view illustrating a procedure for producing the insulating material in FIG. [Figure 4]FIG. 4 is a perspective view illustrating a schematic configuration of the electricity storage unit according to the first embodiment. [Diagram 5] FIG. 5 is an enlarged cross-sectional view that illustrates a connection structure of the electricity storage unit illustrated in FIG. [Figure 6] FIG. 6 is an enlarged cross-sectional view illustrating a schematic structure in the vicinity of a terminal mounting hole of an electricity accumulation device according to a second embodiment. [Figure 7] FIG. 7 is an enlarged cross-sectional view illustrating a schematic structure in the vicinity of a terminal mounting hole of an electricity accumulation device according to a third embodiment. [Figure 8] FIG. 8 is an enlarged cross-sectional view illustrating a schematic structure in the vicinity of a terminal mounting hole of an electricity accumulation device according to a fourth embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing an example of a bus bar that can be used in the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the technology disclosed herein will be described with reference to the drawings. Note that matters other than those specifically mentioned in this specification and necessary for implementing the technology disclosed herein (such as the detailed configuration of the electrode body) can be understood as design matters for a person skilled in the art based on the conventional technology in the field. The technology disclosed here can be implemented based on the contents disclosed in this specification and the technical common sense in the field. In addition, the expression "A to B" indicating a range in this specification includes the meaning of "greater than A" and "smaller than B" as well as the meaning of A or more and B or less.

[0010] In this specification, the term "electricity storage device" refers to a concept that includes a device in which a charge / discharge reaction occurs by 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 includes secondary batteries such as lithium ion secondary batteries, nickel hydrogen batteries, and nickel cadmium batteries, as well as capacitors such as lithium ion capacitors and electric double layer capacitors.

[0011] <First embodiment> 1. Configuration of the energy storage device Hereinafter, one embodiment of the electricity storage device disclosed herein will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view that shows a schematic view of an electricity storage device according to a first embodiment. FIG. 2 is an enlarged cross-sectional view that shows a schematic view of a structure in the vicinity of a terminal mounting hole of the electricity storage device according to the first embodiment. FIG. 3 is an enlarged cross-sectional view that explains a procedure for producing an insulating material in FIG. 2. In addition, the symbols L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom, respectively. In addition, 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 are merely directions defined for convenience of explanation, and do not limit the installation mode of the electricity storage device disclosed herein.

[0012] 1 and 2, the electricity storage device 1 according to this embodiment includes an electrode body 10, a case 20 that houses the electrode body 10 and has a terminal mounting hole 25, an insulating material 30 that continuously covers the peripheral wall 25a and the peripheral parts 20a1 and 20b1 of the terminal mounting hole 25 in the circumferential direction and is joined to the peripheral parts 20a1 and 20b1 of the terminal mounting hole 25, and a current collector 40 that is electrically connected to the electrode body 10 inside the case 20. The current collector 40 is disposed so as to close the terminal mounting hole 25 via the insulating material 30, and is joined to the insulating material 30. The current collector 40 has a terminal portion 44 that is exposed to the outside of the case 20 through the terminal mounting hole 25 and can be electrically connected to an external member. In the electricity storage device 1 according to this embodiment, the terminal portion 44 is located inside the outer surface 20a of the case 20, and the terminal mounting hole 25 is sealed by the insulating material 30 and the current collector 40. With this configuration, it is possible to form a conductive path to the outside of the case 20 and to seal the inside of the case 20 without providing an electrode terminal (external connection member) that protrudes outside the case. As a result, it is possible to contribute to improving the loading efficiency of electrical products. The electricity storage device 1 according to this embodiment will be specifically described below.

[0013] (1) Electrode body 10 The electrode body 10 is a power generating element of the electricity storage device 1. The electricity storage device 1 according to this embodiment includes one electrode body 10. However, the number of electrode bodies is not particularly limited and may be more than one. Although detailed illustration is omitted, the electrode body 10 includes a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate includes a positive electrode core body that is a conductive metal foil (such as aluminum foil) and a positive electrode active material layer applied to the surface of the positive electrode core body. On the other hand, the negative electrode plate includes a negative electrode core body that is a conductive metal foil (such as copper foil) and a negative electrode active material layer applied to the surface of the negative electrode core body. The separator is an insulating sheet interposed between the positive electrode plate and the negative electrode plate. Note that the materials of each member (positive electrode plate, negative electrode plate, separator, etc.) constituting the electrode body 10 can be materials that can be used in general electricity storage devices without particular restrictions, and detailed explanations are omitted because they do not limit the technology disclosed herein.

[0014] The specific structure of the electrode body 10 is not particularly limited. For example, the electrode body 10 may be a wound electrode body in which a laminate including a positive electrode plate, a negative electrode plate, and a separator is wound. The electrode body 10 may be a laminated electrode body in which a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators are laminated. However, regardless of which structure is adopted, connection tabs 12 are formed on both side edges of the electrode body 10 in the width direction X. One of the connection tabs 12 is a positive electrode tab electrically connected to the positive electrode plate. This positive electrode tab is formed, for example, by bundling positive electrode core bodies that are not coated with a positive electrode active material layer. The other connection tab 12 is a negative electrode tab electrically connected to the negative electrode plate. This negative electrode tab is formed by bundling negative electrode core bodies that are not coated with a negative electrode active material layer. As will be described in detail later, these connection tabs 12 are electrically connected to the current collector 40.

[0015] (2) Case 20 The case 20 is a container that houses the electrode body 10 and has a terminal mounting hole 25. Specifically, the case 20 is a flat box-shaped container having an internal space. The electrode body 10 is housed in the internal space of the case 20. Although not shown in the drawings, an electrolyte is also housed inside the case 20. The electrolyte can be any electrolyte that can be used in a general electricity storage device without any particular restrictions, and detailed description thereof will be omitted as it does not limit the technology disclosed herein.

[0016] The case 20 in this embodiment includes a case body 22 and a sealing plate 24. The case body 22 is a box-shaped body having an upper opening. As shown in FIG. 1, the case body 22 includes a bottom 22b that is a long rectangular plate-shaped member, a pair of first side walls 22c that extend upward D from a long side (side along the width direction X) of the bottom 22b, and a pair of second side walls 22d that extend upward D from a short side (side along the depth direction Y) of the bottom 22b. An upper opening surrounded by the upper ends of the first side wall 22c and the second side wall 22d is formed on the upper surface of the case body 22. On the other hand, the sealing plate 24 is a rectangular plate-shaped member that closes the upper opening of the case body 22. Specifically, as shown in FIG. 2, the sealing plate 24 is fitted into the upper opening of the case body 22. The boundary between the case body 22 and the sealing plate 24 is joined by laser welding or the like. Case 20 (case body 22 and sealing plate 24) is preferably a metal member having a certain level of strength or more. Examples of materials for case 20 include metal materials such as aluminum and aluminum alloys.

[0017] As described above, the case 20 is formed with a terminal mounting hole 25. The terminal mounting hole 25 is a through hole penetrating the case 20. The terminal mounting hole 25 is an opening for forming a conductive path from the electrode body 10 inside the case 20 to the outside of the case 20. As shown in FIG. 1, the terminal mounting hole 25 in this embodiment is a circular opening in a plan view. However, the planar shape of the terminal mounting hole is not particularly limited and may be rectangular. In addition, in the electricity storage device 1 according to this embodiment, two terminal mounting holes 25 are formed in the sealing plate 24 of the case 20. Specifically, the terminal mounting holes 25 are formed at both ends of the sealing plate 24 in the width direction X. One of the terminal mounting holes 25 is a positive electrode terminal mounting hole 25P that forms a conductive path with the positive electrode of the electrode body 10. The other terminal mounting hole 25 is a negative electrode terminal mounting hole 25N that forms a conductive path with the negative electrode of the electrode body 10. In the following, the structure around the negative terminal mounting hole 25N will be described as an example.

[0018] (3) Insulation material 30 The insulating material 30 covers the peripheral wall 25a of the terminal mounting hole 25 and the peripheral parts 20a1, 20b1 of the terminal mounting hole 25 continuously in the circumferential direction, and is joined to the peripheral parts 20a1, 20b1 of the terminal mounting hole 25. The insulating material 30 is a member for preventing conduction to the case 20. Specifically, a current collector 40 that forms a conductive path from the electrode body 10 to the outside of the case 20 is attached inside the case 20. In addition, an external member (such as the bus bar 110 in FIG. 4) that connects the electricity storage device 1 and the electric device is attached outside the case 20. Conduction to the case 20 can be prevented by interposing the insulating material 30 between these conductive members and the case 20. The insulating material 30 is made of an insulating resin such as polypropylene resin, polyphenylene sulfide resin, polyamide resin, polyacetal resin, or polyimide resin. In addition, the insulating material 30 has an opening 38 that penetrates the insulating material 30. The insulating material 30 is formed so that the opening 38 overlaps with the terminal mounting hole 25. In other words, the insulating material 30 is disposed so as not to block the terminal mounting hole 25 of the case 20.

[0019] In addition, the insulating material 30 in this embodiment is produced by insert molding. In this insert molding, first, as shown in FIG. 3, the current collector 40 and the mold M are attached to the sealing plate 24. At this time, the positional relationship of each member is adjusted so that a cavity S having a shape corresponding to the insulating material 30 to be produced is generated. Next, a resin material is filled into the inside of the cavity S through the injection hole M1 of the mold M. Then, the insulating material 30 having a shape corresponding to the cavity S is produced by hardening the resin material. When the insulating material 30 is produced by insert molding in this way, the sealing plate 24 and the current collector 40 are integrated through the insulating material 30. As a result, the insulating material 30 covers the peripheral wall 25a of the terminal mounting hole 25 and the peripheral parts 20a1 and 20b1 of the terminal mounting hole 25 continuously in the circumferential direction, and is joined to the peripheral parts 20a1 and 20b1 of the terminal mounting hole 25. After insert molding, the insulating material 30 has an outer insulating portion 32, an inner insulating portion 34, and an in-hole insulating portion 36. The specific shape of each portion will be described below.

[0020] The insulating material 30 includes an external insulating portion 32 joined to a peripheral portion 20a1 of the terminal mounting hole 25 on the outer surface 20a of the case 20. The external insulating portion 32 is a member that prevents electrical conduction between an external member (such as the bus bar 110) and the case 20. Specifically, the external insulating portion 32 is a plate-shaped portion that is arranged along the outer surface 20a of the case 20 (the upper surface 24a of the sealing plate 24). The lower surface 32a of the external insulating portion 32 is joined to the outer surface 20a of the case 20 by insert molding. As shown in FIG. 4, by providing the external insulating portion 32, it is possible to prevent the external member (the bus bar 110) from contacting the case 20 (the sealing plate 24) when connecting the external member to the power storage device 1. The thickness of the external insulating portion 32 is preferably 0.5 mm or more, more preferably 1.0 mm or more, and particularly preferably 2.0 mm or more. This makes it possible to more suitably prevent electrical conduction between the external member and the case 20. On the other hand, the thickness of the external insulating part 32 is preferably 4.0 mm or less, and more preferably 3.0 mm or less, which allows the height dimension of the electricity storage device 1 to be further reduced, thereby further improving the loading efficiency of the electricity storage device in an electrical product.

[0021] The insulating material 30 also includes an internal insulating portion 34 joined to the peripheral portion 20b1 of the terminal mounting hole 25 on the inner surface 20b of the case 20. The internal insulating portion 34 is a member that prevents electrical conduction between the current collector 40 (described later) and the case 20. Specifically, the internal insulating portion 34 is a plate-like portion that is interposed between the inner surface 20b of the case 20 (the lower surface 24b of the sealing plate 24) and the joint portion 42 of the current collector 40. The upper surface 34a of the internal insulating portion 34 is joined to the inner surface 20b of the case 20 by insert molding. The thickness of the internal insulating portion 34 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more. This makes it possible to more suitably prevent electrical conduction between the current collector 40 and the sealing plate 24. On the other hand, the thickness of the internal insulating portion 34 is preferably 2.0 mm or less, and more preferably 1.0 mm or less. This increases the space available for accommodating the electrode assembly 10 within the case 20, which can contribute to improving the performance of the electricity storage device 1.

[0022] The insulating material 30 includes an in-hole insulating portion 36 that is joined to the peripheral wall 25a of the terminal mounting hole 25. In the electricity storage device 1 according to this embodiment, the current collector 40 and the bus bar 110 are connected inside the terminal mounting hole 25, which will be described in detail later. The in-hole insulating portion 36 prevents these conductive members from directly contacting the case 20 (sealing plate 24). Specifically, the in-hole insulating portion 36 is a cylindrical portion extending along the height direction Z. The in-hole insulating portion 36 is disposed inside the terminal mounting hole 25 of the case 20. The outer periphery 36a of the in-hole insulating portion 36 is joined to the peripheral wall 25a of the terminal mounting hole 25. In the insulating material 30 according to this embodiment, the external insulating portion 32 and the internal insulating portion 34 are continuous with each other via the in-hole insulating portion 36. In other words, the external insulating portion 32, the internal insulating portion 34, and the in-hole insulating portion 36 are integrally formed. The thickness of the in-hole insulation 36 is preferably 0.5 mm or more, more preferably 1.0 mm or more, and particularly preferably 2.0 mm or more. This prevents the in-hole insulation 36 from being damaged by friction or heat when connecting the current collector 40 and the bus bar 110. On the other hand, the thickness of the in-hole insulation 36 is preferably 4.0 mm or less, and more preferably 3.0 mm or less. This ensures a sufficient size for the terminal mounting hole 25, making it easy to connect the current collector 40 and the bus bar 110.

[0023] Moreover, the insulating material 30 in this embodiment has a protruding portion 34c that protrudes downward D from a part of the internal insulating portion 34 (the inner portion in the width direction X). This can regulate the up and down movement of the electrode body 10 in the case 20. As a result, it is possible to prevent the electrode body 10 from contacting the sealing plate 24 and the connection tab 12 from being damaged. The thickness (protruding amount) of the protruding portion 34c is preferably 2.0 mm or more, and more preferably 3.0 mm or more. This can more suitably regulate the up and down movement of the electrode body 10. Meanwhile, the thickness of the protruding portion 34c is preferably 5.0 mm or less, and more preferably 4.0 mm or less. This can ensure a sufficient storage space for the electrode body 10 in the case 20.

[0024] In this embodiment, the surfaces of the metal members (sealing plate 24, current collector 40) that come into contact with the insulating material 30 are roughened. Specifically, the roughened portions are the peripheral portion 20a1 of the terminal mounting hole 25 on the outer surface 20a of the case 20, the peripheral portion 20b1 of the terminal mounting hole 25 on the inner surface 20b of the case 20, the peripheral wall 25a of the terminal mounting hole 25, and the surface of the current collector 40 (the upper surface 42a of the joint 42) that is joined to the insulating material 30. Thereby, when insert molding is performed, the resin material penetrates into the unevenness of the surfaces of each metal member. As a result, an anchor effect is generated, so that the insulating material 30 and the metal member can be joined more firmly. Note that the roughening may be performed on at least one of the above-mentioned surfaces. Even in this case, the joining strength between the insulating material 30 and the metal member can be suitably improved. In addition, this roughening does not limit the technology disclosed herein. That is, even if the surface is not roughened, the insulating material 30 and the metal member can be sufficiently integrated by insert molding.

[0025] (4) Current collector 40 The current collector 40 is a conductive member electrically connected to the electrode body 10 inside the case 20. Specifically, the current collector 40 includes an internal current collecting portion 46 extending along the height direction Z. This internal current collecting portion 46 is a plate-shaped portion connected to the connection tab 12 of the electrode body 10. The internal current collecting portion 46 is preferably made of the same metal material as the connection tab 12 to be connected. For example, as described above, the negative electrode tab is made of a negative electrode core body that is copper foil. In this case, the internal current collecting portion 46 is preferably made of a copper-based material (copper, copper alloy, etc.). This allows the current collector 40 and the electrode body 10 to be connected firmly with low resistance.

[0026] Moreover, the current collector 40 in this embodiment is disposed so as to cover the terminal mounting hole 25 via the insulating material 30, and is joined to the insulating material 30. The current collector 40 has a terminal portion 44 that is exposed to the outside of the case 20 through the terminal mounting hole 25 and can be electrically connected to an external member. A current collector having such a configuration will be specifically described below.

[0027] First, the current collector 40 has a joint 42 which is a plate-like member joined to the insulating material 30. This joint 42 is joined to the lower surface 34b of the internal insulating part 34 so as to close the terminal mounting hole 25 inside the case 20. More specifically, the joint 42 is formed by bending the upper end of the internal current collecting part 46 so as to face the sealing plate 24. As a result, the joint 42 faces the inner surface 20b of the case 20 with the internal insulating part 34 sandwiched therebetween. Then, the upper surface 42a of the joint 42 is joined to the lower surface 34b of the internal insulating part 34 by insert molding. As a result, the lower end of the terminal mounting hole 25 is closed by the joint 42.

[0028] The terminal portion 44 is exposed to the outside of the case 20 through the terminal mounting hole 25. This allows an external member such as a bus bar to be electrically connected to the current collector 40. Specifically, as shown in FIG. 2, in this embodiment, the upper end of the terminal mounting hole 25 is open. As a result, a part of the current collector 40 (the terminal portion 44) is exposed to the outside of the case 20. This allows a part of the external member (the connection protrusion 112 of the bus bar 110) to be inserted into the terminal mounting hole 25 from outside the case 20 (see FIG. 4). As a result, the current collector 40 and the external member can be electrically connected to each other.

[0029] The terminal portion 44 of the electricity storage device 1 according to this embodiment is located inward from the outer surface 20a of the case 20. In other words, as shown in FIG. 2, the upper surface 44a of the terminal portion 44 is located on the lower D side from the outline L1 along the outer surface 20a of the case 20. This can prevent a part of the current collector 40 from protruding outside the case 20. In addition, in the electricity storage device 1 according to this embodiment, the terminal mounting hole 25 is sealed by the insulating material 30 and the current collector 40 (the joint portion 42 and the terminal portion 44). This can prevent the electrolyte from leaking out and foreign matter from entering. As described above, according to the electricity storage device 1 according to this embodiment, it is possible to form a conductive path to the outside of the case 20 and to seal the inside of the case 20 without providing an external connection portion. That is, according to this embodiment, since it is possible to eliminate the conductive member protruding outside the case 20, it is possible to reduce the height dimension of the electricity storage device 1. As a result, it is possible to improve the loading efficiency of the electricity storage device 1 in an electrical product.

[0030] In this embodiment, the terminal portion 44 is a convex terminal portion inserted into the terminal mounting hole 25 from the inside of the case 20. This raises the position of the upper surface 44a of the terminal portion 44 in the terminal mounting hole 25, making it easier to connect the terminal portion 44 to an external member. In addition, when the convex terminal portion 44 is inserted into the terminal mounting hole 25, the movement of the current collector 40 in the horizontal direction (width direction X and depth direction Y) is restricted. This can also suppress peeling of the joint interface between the joint portion 42 and the internal insulating portion 34. Note that as the position of the upper surface 44a of the terminal portion 44 in the terminal mounting hole 25 is raised, the connection between the terminal portion 44 and the external member tends to become easier. From this viewpoint, the distance H1 from the outer surface 20a of the case 20 to the upper surface 44a of the terminal portion 44 is preferably 2.0 mm or less, more preferably 1.0 mm or less, and even more preferably 0.5 mm or less. Furthermore, the upper surface 44a of the terminal portion 44 may be at substantially the same height as the outer surface 20a of the case 20 (that is, the distance H1 is 0 mm). In this case, it becomes even easier to connect the terminal portion 44 to an external member.

[0031] As described above, the current collector 40 shown in FIG. 2 includes a joint 42, which is a plate-like member joined to the insulating material 30. In this case, the convex terminal portion 44 shown in FIG. 2 is a columnar member joined to the upper surface 42a of the joint 42. This ensures a sufficient thickness for the terminal portion 44. As a result, a suitable welding depth can be ensured when connecting the terminal portion 44 to an external member by laser welding or the like. Furthermore, when such a configuration is adopted, the material of the terminal portion 44 can be freely selected without being affected by the materials of the other portions (joint 42, internal current collecting portion 46).

[0032] For example, as shown in FIG. 2, a clad material having a first layer 47 and a second layer 45 can be used as the terminal portion 44. The first layer 47 of the terminal portion 44 is joined to the upper surface 42a of the joint portion 42 and is a layer made of the same type of metal as the joint portion 42. This allows the terminal portion 44 and the joint portion 42 to be firmly joined. On the other hand, the second layer 45 is exposed to the outside of the case 20 through the terminal mounting hole 25 and is a layer made of a metal different from that of the first layer 47. This allows a metal that is easy to connect to an external member to be disposed on the upper surface 44a of the terminal portion 44. For example, in the negative electrode side current collector 40, a copper-based material is used for the internal current collector 46 and the joint portion 42 in consideration of the connectivity with the negative electrode tab. On the other hand, in the construction of the power storage unit 100 described later, an aluminum-based material is used for the external member (bus bar 110) in consideration of the connectivity with the joint portion of the positive electrode side current collector. In this case, it is preferable that the first layer 47 of the terminal portion 44 is made of copper, and the second layer 45 is made of aluminum. This makes it possible to form a copper-copper bonding interface between the terminal portion 44 and the joint portion 42, and also to form an aluminum-aluminum bonding interface between the terminal portion 44 and the bus bar 110. As a result, a strong, low-resistance conductive path can be formed from the electrode body 10 to the bus bar 110.

[0033] 2. Configuration of the Energy Storage Unit Next, a description will be given of an electricity storage unit 100 constructed using the electricity storage device 1 having the above-mentioned configuration. Fig. 4 is a perspective view showing an electricity storage unit according to a first embodiment. Fig. 5 is an enlarged cross-sectional view showing a connection structure of the electricity storage unit shown in Fig. 4.

[0034] The power storage unit 100 shown in FIG. 4 includes a plurality of power storage devices 1. Specifically, in this power storage unit 100, the plurality of power storage devices 1 are arranged along the depth direction Y so that the first side walls 22c of the cases 20 face each other. The number of the power storage devices 1 included in the power storage unit 100 is not particularly specified, and is appropriately changed according to the purpose of the power storage unit 100 (required power, specifications, etc. of the electric appliance to be used). In addition, in the power storage unit 100 according to the present embodiment, it is not necessary for all of the plurality of power storage devices 1 to have the above configuration. For example, when the power storage unit is mounted in an electric appliance, only some of the plurality of power storage devices interfere with other components, so that it may be necessary to reduce the height dimension of the entire power storage unit. In such a case, it is preferable to adopt the above configuration only for the power storage devices that interfere with other components. This can improve the loading efficiency of the power storage devices in the electric appliance.

[0035] A pair of end plates 120 are arranged on both outer sides in the arrangement direction (depth direction Y) of the electricity storage units 100. The pair of end plates 120 are bridged by a restraining beam member 130. This allows a restraining pressure along the arrangement direction to be applied to each of the electricity storage devices 1. Furthermore, a resin buffer member 150 is arranged between each of the arranged electricity storage devices 1. This allows the restraining pressure applied to the electricity storage devices 1 to be uniform.

[0036] The energy storage unit 100 includes a plurality of bus bars 110 that electrically connect the plurality of energy storage devices 1. The bus bars 110 are joined to the terminal portions 44 of the respective energy storage devices 1. Specifically, in the energy storage unit 100 shown in FIG. 4, the plurality of energy storage devices 1 are arranged such that the positive electrode terminal mounting hole 25P of one energy storage device 1 and the negative electrode terminal mounting hole 25N of the other energy storage device 1 are adjacent to each other. The bus bars 110 are connected to the terminal portions 44 present inside each of a pair of adjacent terminal mounting holes 25. The bus bars 110 are made of the same metal material (e.g., aluminum) as the positive electrode terminal portion 44.

[0037] As shown in FIG. 5, the busbar 110 in this embodiment includes a connection protrusion 112 that is inserted into the terminal mounting hole 25 from the outside of the case 20 and is connected to the terminal portion 44 of the current collector 40. This allows the terminal portion 44 to be easily connected to the busbar 110 even when the terminal portion 44 is disposed inward (downward D) from the outer surface 20a of the case 20. Specifically, the connection protrusion 112 is a portion of the busbar 110 that is bent so as to protrude toward the downward D. The connection protrusion 112 of the busbar 110 is inserted into the terminal mounting hole 25 from the upper U in the height direction Z. This brings the connection protrusion 112 into contact with the upper surface 44a of the terminal portion 44. In this state, the connection protrusion 112 and the terminal portion 44 are laser-welded to each other. This forms a welded portion that straddles the connection protrusion 112 and the terminal portion 44, and the terminal portion 44 and the busbar 110 are electrically connected to each other.

[0038] In the technology disclosed herein, the external member connected to the power storage device is not limited to the bus bar 110 having the above configuration. For example, an electric wire or the like may be used as the external member. These external members can also be easily inserted into the terminal mounting holes, and therefore can be appropriately connected to the current collector (terminal portion) that is arranged inward from the outer surface of the case.

[0039] An embodiment of the technology disclosed herein has been described above. However, the technology disclosed herein is not limited to the above-mentioned embodiment. Other embodiments of the technology disclosed herein will be described below. FIG. 6 is an enlarged cross-sectional view that typically shows a structure in the vicinity of a terminal mounting hole of an electricity storage device according to a second embodiment. FIG. 7 is an enlarged cross-sectional view that typically shows a structure in the vicinity of a terminal mounting hole of an electricity storage device according to a third embodiment. FIG. 8 is an enlarged cross-sectional view that typically shows a structure in the vicinity of a terminal mounting hole of an electricity storage device according to a fourth embodiment. FIG. 9 is a cross-sectional view that typically shows an example of a bus bar that can be used in the fourth embodiment.

[0040] <Second embodiment> As shown in FIG. 2, the terminal portion 44 in the first embodiment is a columnar clad material including a first layer 47 and a second layer 45. However, the terminal portion in the technology disclosed herein is not limited to a columnar clad material. For example, the terminal portion 44 may be a columnar member made of a single metal material (see FIG. 6). Even when such a configuration is adopted, the loading efficiency of the electricity storage device 1 can be improved by arranging the upper surface 44a of the terminal portion 44 inward (downward D) from the outer surface 20a of the case 20.

[0041] The terminal portion 44 made of a single metal material can be particularly suitably used when the joint portion 42 and the external member (bus bar) are made of the same material. For example, in the positive electrode side current collector 40, an aluminum-based material is used for the internal current collector portion 46 and the joint portion 42 in consideration of the connectivity with the positive electrode tab (aluminum foil). On the other hand, as described above, an aluminum-based material is also used for the bus bar 110 when constructing the electricity storage unit 100 (see FIG. 4). In such a configuration, even if a clad material is not used for the terminal portion 44, the conductive path from the electrode body 10 to the bus bar 110 can be constructed of an aluminum-based material, so that a strong and low-resistance conductive path can be formed.

[0042] <Third embodiment> In the first and second embodiments, the columnar terminal portion 44 is joined to the upper surface 42a of the joint portion 42 (see FIG. 2 and FIG. 6). However, the convex terminal portion 44 is not limited to this configuration. For example, when the joint portion 42 is a plate-shaped member, the convex terminal portion 44 can be formed by bending the joint portion 42 (see FIG. 7). This convex terminal portion 44 can be formed by performing a press process on the plate-shaped joint portion 42. Even when the terminal portion 44 having such a configuration is inserted into the terminal mounting hole 25, the connection between the terminal portion 44 and an external member is facilitated, and the movement of the current collector 40 in the horizontal direction can be restricted. In addition, according to the present embodiment, the number of parts of the current collector 40 can be reduced, which contributes to reducing material costs.

[0043] <Fourth embodiment> In the first to third embodiments, the convex terminal portion 44 is inserted into the terminal mounting hole 25. However, the current collector in the technology disclosed herein does not have to have a convex terminal portion. For example, as shown in FIG. 8, the joint portion 42 and the terminal portion 44 may form a continuous flat surface. Even when such a configuration is adopted, the terminal mounting hole 25 can be sealed by the insulating material 30 and the terminal portion 44. Even when such a configuration is adopted, the terminal portion 44 is exposed to the outside of the case 20 through the terminal mounting hole 25, so that the external member and the current collector 40 can be electrically connected. Also in this case, the terminal portion 44 is disposed inward (downward D) from the outer surface 20a of the case 20, so that the loading efficiency of the electricity storage device in the electrical product can be improved.

[0044] When the fourth embodiment is adopted, it is preferable to increase the protrusion amount of the connection protrusion of the bus bar. This allows the bus bar and the terminal portion 44 to be appropriately connected. Also, as shown in FIG. 9, the connection protrusion 112 of the bus bar 110 may be made of a clad material. In this case, the connection protrusion 112 is joined to the body 114 of the bus bar 110 and has an upper layer 112a made of the same metal as the body 114, and a lower layer 112b arranged below the upper layer 112a and made of the same metal as the terminal portion 44 of the electricity storage device 1. This makes it possible to easily form a strong and low-resistance conductive path even when the terminal portion 44 is not a convex member.

[0045] 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 changes to the specific examples exemplified above. In other words, the technology disclosed herein includes the embodiments described in items 1 to 8 below.

[0046] [Item 1] An electrode body; a case that houses the electrode body and has a terminal mounting hole; an insulating material that covers a peripheral wall and a peripheral edge portion of the terminal mounting hole continuously in a circumferential direction and is joined to the peripheral edge portion of the terminal mounting hole; a current collector electrically connected to the electrode body inside the case; Equipped with The current collector is The insulating material is disposed so as to close the terminal mounting hole, bonded to the insulating material; a terminal portion exposed to the outside of the case through the terminal mounting hole and capable of being electrically connected to an external member; the terminal portion is located inwardly of an outer surface of the case, and the terminal mounting hole is sealed by the insulating material and the current collector.

[0047] [Item 2] 2. The power storage device according to claim 1, wherein the terminal portion is a convex terminal portion inserted into the terminal mounting hole from the inside of the case.

[0048] [Item 3] The current collector includes a joint portion which is a plate-like member joined to the insulating material, 3. The power storage device according to item 2, wherein the convex terminal portion is a portion formed by bending the joint portion.

[0049] [Item 4] The current collector includes a joint portion which is a plate-like member joined to the insulating material, 3. The power storage device according to item 2, wherein the convex terminal portion is a columnar member joined to an upper surface of the joint portion.

[0050] [Item 5] The pillar-shaped terminal portion is A first layer is joined to an upper surface of the joint and is made of the same metal as the joint; a second layer exposed to the outside of the case through the terminal mounting hole and made of a metal different from that of the first layer; 5. The power storage device according to item 4, comprising:

[0051] [Item 6] 6. The energy storage device according to any one of items 1 to 5, wherein a roughening process is applied to at least one of a peripheral portion of the terminal mounting hole on an outer surface of the case, a peripheral portion of the terminal mounting hole on an inner surface of the case, a peripheral wall of the terminal mounting hole, and a surface of the current collector joined to the insulating material.

[0052] [Item 7] A plurality of power storage devices; a plurality of bus bars electrically connecting the plurality of power storage devices; Equipped with An electricity storage unit, wherein at least one of the plurality of electricity storage devices is the electricity storage device according to any one of items 1 to 6, and the bus bar is joined to the terminal portion of the electricity storage device.

[0053] [Item 8] 8. The energy storage unit according to item 7, wherein the bus bar is inserted into the terminal mounting hole from the outside of the case and has a connection protrusion that is connected to the terminal portion of the current collector. [Explanation of symbols]

[0054] 1. Energy storage devices 10 Electrode body 12 Connections tab 20 cases 22 Case body 24 Sealing plate 25 Terminal mounting hole 30 Insulation Materials 32 Outer insulation 34 Internal insulation 36 Inner hole insulation 38 Opening 40 Current collector 42 Joint 44 Terminal section 46 Internal current collector 100 Energy Storage Unit 110 Busbar 112 Connection protrusion 120 End Plate 130 Restraint beam material 150 Cushioning material

Claims

1. An electrode body; a case that houses the electrode body and has a terminal mounting hole; an insulating material that covers a peripheral wall and a peripheral edge portion of the terminal mounting hole continuously in a circumferential direction and is joined to the peripheral edge portion of the terminal mounting hole; a current collector electrically connected to the electrode body inside the case; Equipped with The current collector is The insulating material is disposed so as to close the terminal mounting hole, bonded to the insulating material; a terminal portion exposed to the outside of the case through the terminal mounting hole and capable of being electrically connected to an external member; the terminal portion is located inwardly of an outer surface of the case, and the terminal mounting hole is sealed by the insulating material and the current collector.

2. The power storage device according to claim 1 , wherein the terminal portion is a convex terminal portion that is inserted into the terminal mounting hole from an inside side of the case.

3. The current collector includes a joint portion which is a plate-like member joined to the insulating material, The power storage device according to claim 2 , wherein the convex terminal portion is a portion formed by bending the joint portion.

4. The current collector includes a joint portion which is a plate-like member joined to the insulating material, The power storage device according to claim 2 , wherein the protruding terminal portion is a columnar member joined to an upper surface of the joint portion.

5. The pillar-shaped terminal portion is a first layer joined to an upper surface of the joint and made of the same metal as the joint; a second layer exposed to the outside of the case through the terminal mounting hole and made of a metal different from that of the first layer; The power storage device according to claim 4 .

6. 6. The energy storage device according to claim 1, wherein a roughening process is applied to at least one of the following: a peripheral portion of the terminal mounting hole on the outer surface of the case; a peripheral portion of the terminal mounting hole on the inner surface of the case; a peripheral wall of the terminal mounting hole; and a surface of the current collector joined to the insulating material.

7. A plurality of power storage devices; a plurality of bus bars electrically connecting the plurality of power storage devices; Equipped with An electricity storage unit, wherein at least one of the plurality of electricity storage devices is the electricity storage device according to claim 1, and the bus bar is joined to the terminal portion of the electricity storage device.

8. The electricity storage unit according to claim 7 , wherein the bus bar is inserted into the terminal mounting hole from an external side of the case and includes a connection protrusion connected to the terminal portion of the current collector.

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