Energy storage module

Abstract

To provide a technology which achieves reduction of the weight of a power storage module handling increased voltage.SOLUTION: A power storage module 100 disposed here includes: a plurality of power storage devices 1; a plurality of bus bars 110; a case 120; and a positive electrode 130 and a negative electrode 140. The hexagonal case 120 includes: a case body 121 having a first surface 121a and an opening 121h; and a sealing plate 122 which seals the opening 121h. In the case 120, the plurality of power storage devices 1 arranged in a first direction P are sandwiched between the first surface 121a and the sealing plate 122. Further, at a positive electrode inner conductive part 132 of the positive terminal 130, the positive terminal 130 is connected to a positive electrode tab 22t included in the power storage device 1 at one end in the first direction P. At a negative electrode inner conductive part 142 of a negative terminal 140, the negative terminal 140 is connected to a negative electrode tab 24t included in the power storage device 1 at the other end in the first direction P.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a power storage module.

Background Art

[0002] Patent Document 1 discloses a restraint jig that compresses a laminate formed by stacking a large number of workpieces in the front-rear direction at a predetermined pressure, restrains the laminate while maintaining the pressure, and releases the pressure of the laminate in the restrained state to release the restraint. Such a restraint jig includes a front fixing plate and a rear fixing plate, a front moving plate and a rear moving plate, bolts, lock nuts, a shaft, a wedge hole, a wedge, and a slit. The front fixing plate and the rear fixing plate are erected facing each other in the front-rear direction on a pedestal having a horizontal plane. The front moving plate and the rear moving plate face each other in the front-rear direction and are movable in the front-rear direction between the front fixing plate and the rear fixing plate. The bolt extends forward from the front surface of the front moving plate and penetrates the front fixing plate. The lock nut is screwed onto the bolt between the front fixing plate and the front moving plate. The shaft extends rearward from the rear surface of the rear moving plate and penetrates the rear fixing plate. The wedge hole horizontally crosses a hole for penetrating the shaft drilled in the rear fixing plate in the vertical direction and opens on the upper surface of the rear fixing plate. The wedge is driven into the wedge hole from above the rear fixing plate with the tip downward. The slit extends in the front-rear direction while penetrating the shaft vertically. The front end surface of the slit is a friction surface with the wedge, and the friction surface and the wedge are formed such that when the wedge is driven to a predetermined depth, the shaft is urged forward to move the rear moving plate to a predetermined relative position with respect to the pedestal. This document describes that according to the restraint jig having such a configuration, the laminate can be easily compressed and restrained, and the restraint can be easily released. Further, this document describes that it is applicable to a process of manufacturing an assembled battery (stack) by stacking a large number of secondary battery cells in a compressed state with a strong pressure, an inspection process of the stack, and the like.

[0003] The charging method disclosed in Patent Document 2 involves housing a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt in a battery container, and charging a non-aqueous secondary battery having a flat shape with a thickness of less than 12 mm, an energy capacity of 30 Wh or more, and a volumetric energy density of 180 Wh / l or more. This charging method is characterized in that, when the maximum operating voltage range of the non-aqueous secondary battery is V2 to V1 (V2 > V1), and the discharge capacity obtained in the maximum operating voltage range in the initial state is C, charging and discharging are performed within a capacity range of 0.8 C or less with respect to V1. This document states that the cycle life of the secondary battery can be greatly extended by this charging method.

[0004] In the flat rectangular battery disclosed in Patent Document 3, the main body case is formed from a semi-shell made by processing a metal plate and providing a flange around the opening of a recess. The electrode plate group is housed within the recess. A metal cover plate is disposed with its peripheral portion overlapping the flange and is joined to the flange by welding. Furthermore, in this battery, a recess is formed in the main body case and / or cover plate in a direction that reduces the thickness of the battery. This publication states that when the electrode plate group housed in the case expands or the internal pressure rises, and a force acting in the bulging direction acts on the case, the recess in the cover plate, which is formed with lower deformation strength than the main body case, bulges outward, so the overall thickness of the case is not affected, and the device in which the flat rectangular battery is installed is not affected by the bulging. For this reason, it is stated that this configuration can contribute to achieving a thinner device.

[0005] Patent Document 4 discloses a non-aqueous electrolyte secondary battery comprising an electrode body, an outer casing, lead tabs, an insulating plate, and an insulating lid. The electrode body includes a positive electrode and a negative electrode. The outer casing includes a first member and a second member that are positioned opposite each other in the thickness direction of the electrode body and are joined together to house the electrode body. The lead tabs are electrically connected to one of the positive electrode and the negative electrode. The insulating plate is located between the first member and the lead tabs in the thickness direction. The insulating lid is located between the lead tabs and the second member in the thickness direction. This document states that with this configuration, it is possible to obtain a non-aqueous electrolyte secondary battery that can be made thinner while preventing contact between the lead tabs and the outer casing. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-189960 [Patent Document 2] Japanese Patent Publication No. 2002-260743 [Patent Document 3] Japanese Patent Publication No. 2004-103368 [Patent Document 4] Japanese Patent Publication No. 2015-176779 [Overview of the project] [Problems that the invention aims to solve]

[0007] By the way, the inventors of this invention want to make the high-voltage energy storage modules lighter. [Means for solving the problem]

[0008] The energy storage module disclosed herein comprises a plurality of energy storage devices, a plurality of busbars, a case, a positive terminal, and a negative terminal. The plurality of energy storage devices each have a positive tab and a negative tab, and a pair of wide faces. The plurality of energy storage devices are arranged in a first direction with their wide faces facing each other. The plurality of busbars connect two adjacent energy storage devices in series in the first direction. The case is a hexahedral case that houses both the plurality of energy storage devices and the plurality of busbars. The case also comprises a case body having the widest of the six faces, the first face, and an opening facing the first face, and a sealing plate shaped to match the shape of the opening that seals the opening. The positive terminal and the negative terminal are attached to the case body. Inside the case, the plurality of energy storage devices arranged in the first direction are sandwiched between the first face and the sealing plate. The positive terminal has a positive outer conductive portion and a positive inner conductive portion. The positive electrode outer conductive part is located on the outside of the case body. The positive electrode inner conductive part is located on the inside of the case body, accessed from the positive electrode outer conductive part through a first mounting hole provided in the case body. The positive electrode inner conductive part is connected to the positive electrode tab of the energy storage device at one end in the first direction. The negative electrode terminal has a negative electrode outer conductive part and a negative electrode inner conductive part. The negative electrode outer conductive part is located on the outside of the case body. The negative electrode inner conductive part is located on the inside of the case body, accessed from the negative electrode outer conductive part through a second mounting hole provided in the case body. The negative electrode inner conductive part is connected to the negative electrode tab of the energy storage device at the other end in the first direction. Energy storage modules with this configuration achieve high voltage by connecting multiple energy storage devices in series. Furthermore, the above-described current collection structure makes the module lightweight.

[0009] In one preferred embodiment of the energy storage module disclosed herein, both a positive terminal and a negative terminal are provided on one of the sides of the case sandwiched between the first surface and the sealing plate. This configuration allows for a lighter energy storage module.

[0010] In another preferred embodiment of the energy storage module disclosed herein, the energy storage device comprises an electrode body and a resin film casing that houses the electrode body. This configuration further enhances the weight reduction effect of the energy storage module.

[0011] In another preferred embodiment of the energy storage module disclosed herein, at least one of the sealing plate and the first surface has a protruding portion that extends inward toward the interior of the case body. This configuration further enhances the weight reduction effect of the energy storage module. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a perspective view of the energy storage module 100. [Figure 2] Figure 2 is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3 is a perspective view of multiple energy storage devices 1. [Figure 4] Figure 4 is a perspective view of the energy storage device 1. [Figure 5] Figure 5 is a schematic diagram of the electrode body 20. [Figure 6] Figure 6 is a magnified view of a portion of Figure 3. [Figure 7] Figure 7 is a magnified view of a portion of Figure 3. [Figure 8] Figure 8 is a perspective view of the positive terminal 130. [Figure 9] Figure 9 is a perspective view of the negative terminal 140. [Modes for carrying out the invention]

[0013] Hereinafter, an embodiment of the technology disclosed herein will be described. The embodiments described herein are not intended to particularly limit the technology disclosed herein. The technology disclosed herein is not limited to the embodiments described herein unless otherwise specified. The drawings are schematically drawn and do not necessarily reflect the actual objects. Also, members and parts having the same function are appropriately given the same reference numerals, and duplicate descriptions are omitted. In addition, the notation "A~B" indicating a numerical range means "A or more and B or less" and also includes the meaning of "exceeding A and less than B" unless otherwise specified.

[0014] As used herein, the "electric energy storage device" refers to a device in which a charge carrier moves between a pair of electrodes (a positive electrode and a negative electrode) through an electrolyte to cause a charge-discharge reaction. Such electric energy storage devices include secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries; capacitors such as lithium-ion capacitors and electric double layer capacitors. Hereinafter, embodiments in the case of targeting an electric energy storage module including a lithium-ion secondary battery as the above-described electric energy storage device will be described.

[0015] FIG. 1 is a perspective view of an electric energy storage module 100. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. FIG. 2 shows a cross-sectional view along the third surface 121d of the case 120. FIG. 3 is a perspective view of a plurality of electric energy storage devices 1. FIG. 3 shows a plurality of electric energy storage devices 1 arranged with their wide surfaces 1a facing each other along the first direction P. As will be described later, the electric energy storage device 1 includes an exterior body 10 (see FIG. 4), but for convenience of explanation, the illustration of the exterior body 10 is omitted for the plurality of electric energy storage devices 1 shown in FIG. 3 (the same applies to FIGS. 6 and 7). FIG. 4 is a perspective view of the electric energy storage device 1. FIG. 4 shows one electric energy storage device 1. Also, a first bus bar 111 and a second bus bar 112 are attached to the electric energy storage device 1 shown in FIG. 4.

[0016] <Electric energy storage module 100> According to the technology disclosed herein, a power storage module 100 is provided. As shown in FIGS. 1 to 3, the power storage module 100 includes a plurality of power storage devices 1, a plurality of bus bars 110, a case 120, a positive electrode terminal 130, a negative electrode terminal 140, a positive electrode current collecting member 150, a negative electrode current collecting member 160, and an insulating member 170.

[0017] - Power storage device 1 - In the form shown in FIGS. 1 to 3, the power storage device 1 has a flat shape and has a pair of opposing wide surfaces 1a. Also, in the power storage module 100, the plurality of power storage devices 1 are arranged in the first direction P with the wide surfaces 1a facing each other. As shown in FIGS. 1 and 2, the plurality of power storage devices 1 arranged in the first direction P are sandwiched between the first surface 121a and the sealing plate 122 within the case 120. Here, the wide surface 1a of the power storage device 1 faces the first surface 121a and the sealing plate 122. In the form shown in FIG. 2, five power storage devices 1 are accommodated within the case 120. However, the number of power storage devices 1 is not limited and can be appropriately changed depending on, for example, the voltage, output, capacity, etc. desired for the power storage module 100.

[0018] As shown in FIG. 3, in two adjacent power storage devices 1 arranged in the first direction P, in the same direction, the positive electrode tab group 25 of one power storage device 1 and the negative electrode tab group 27 of the other power storage device 1 are adjacent. As will be described later, a bus bar 110 is bridged between the positive electrode tab group 25 of one power storage device 1 and the negative electrode tab group 27 of the other power storage device 1, and the two adjacent power storage devices 1 are connected in series.

[0019] As shown in Figures 2 and 4, the energy storage device 1 comprises an outer casing 10, an electrode body 20, and an electrolyte (not shown). The outer casing 10 is, for example, a component that houses the electrode body 20 and the electrolyte. In this embodiment, the outer casing 10 is made of a resin film. For example, the resin film can be molded into a bag shape, and the electrode body 20 and the electrolyte can be housed inside the bag-shaped resin film, with the open portion heat-sealed to create a sealed outer casing 10. In the configuration shown in Figure 2, at least the positive electrode tab group 25 and the negative electrode tab group 27 are housed inside the outer casing 10. Before heat-sealing, the outer casing 10 houses the electrode body 20, in which the positive electrode tab group 25 and the first busbar 111 are joined, and the negative electrode tab group 27 and the second busbar 112 are joined. In this case, it is preferable that both the first busbar 111 and the second busbar 112 are placed in the open portion of the outer casing 10. From the viewpoint of sealing the energy storage device 1, it is preferable that the joint between the positive electrode tab group 25 and the first busbar 111, and the joint between the negative electrode tab group 27 and the second busbar 112, be housed inside the outer casing 10. The heat welding means is not particularly limited, and conventionally known heat welding devices can be used.

[0020] Examples of materials for the resin film include polyolefins such as polyethylene (PE) and polypropylene (PP); polyesters such as polyethylene terephthalate (PET); and others. Although not particularly limited, a resin film having a two-layer structure of polypropylene and polyethylene terephthalate is preferably used. In the energy storage device 1, by making the outer casing 10 that houses the electrode body 20 out of a resin film, the weight of each individual energy storage device 1 can be reduced, and consequently, the weight of the entire energy storage module 100 can be reduced. Furthermore, the manufacturing cost of the energy storage module 100 can be reduced. In addition, the restraining effect of the case 120 on the energy storage device 1 can be enhanced. Moreover, since the outer casing 10 does not contain metal components, its insulating properties can be improved, and the safety of using the energy storage module 100 can be enhanced. Note that the constituent materials of the outer casing 10 are not limited to those described herein. In other embodiments, such constituent materials may be laminate films.

[0021] Figure 5 is a schematic diagram of the electrode body 20. The electrode body 20 is a power generation element of the energy storage device 1, for example, having a positive electrode and a negative electrode. As shown in Figure 5, the electrode body 20 is a wound electrode body in which a long sheet-like positive electrode 22 and a long sheet-like negative electrode 24 are wound in the longitudinal direction LD of the sheet with a separator 23 interposed between them. The electrode body 20 can be manufactured, for example, by winding the positive electrode 22, the negative electrode 24 and the separator 23 to form a cylindrical body, and then press-molding this cylindrical body. In this embodiment, the electrode body 20 has a flattened shape. As shown in Figures 2 to 5, the electrode body 20 is housed in the outer casing 10 such that the winding axis direction WD and the vertical direction of the energy storage device 1 are substantially parallel. Furthermore, the winding axis WL of the electrode body 20 is approximately parallel to the first surface 121a and the third surfaces 121d, 121e and the sealing plate 122 of the case 120, and is approximately perpendicular to the second surfaces 121b, 121c (see Figures 1 and 5).

[0022] In this embodiment, the electrode body 20 has a pair of opposing flat surfaces 20a and a pair of opposing first end surfaces 20b and second end surfaces 20c. In this embodiment, the flat surface 20a is the widest rectangular surface with the largest area among the surfaces constituting the electrode body 20 (see Figures 2 and 5). The first end surface 20b and the second end surface 20c are two surfaces that lie between one flat surface 20a and the other flat surface 20a, and are surfaces that extend from a pair of opposing long sides of the flat surface 20a. The flat surface 20a of the electrode body 20 faces the first surface 121a and the sealing plate 122. The first end surface 20b faces the second surface 121b, and the second end surface 20c faces the second surface 121c. The first end face 20b and the second end face 20c are, in this case, the stacked surfaces of the positive electrode 22, the negative electrode 24, and the separator 23, and are open surfaces.

[0023] As shown in Figure 5, the positive electrode 22 has a long, strip-shaped positive electrode current collector foil 22c (e.g., aluminum foil) and a positive electrode active material layer 22a fixed to at least one surface of the positive electrode current collector foil 22c. Although not particularly limited, a protective layer 22p may be provided on one side edge of the positive electrode 22 in the winding axis direction WD, if necessary. The constituent materials of the positive electrode active material layer 22a and the protective layer 22p may be any materials used in this type of energy storage device (in this embodiment, a lithium-ion secondary battery) without any particular limitations.

[0024] Multiple positive electrode tabs 22t are provided at one end of the positive electrode current collector foil 22c in the winding axis direction WD (upper end in Figure 5). The multiple positive electrode tabs 22t protrude toward one end of the winding axis direction WD (upper end in Figure 5). The multiple positive electrode tabs 22t are provided at intervals (intermittently) along the longitudinal direction LD of the positive electrode 22. The positive electrode tabs 22t are part of the positive electrode current collector foil 22c and are portions of the positive electrode current collector foil 22c where the positive electrode active material layer 22a is not formed (unactive material layer formed portion). In the embodiment shown in Figure 5, a protective layer 22p is provided on the base end side of the positive electrode tabs 22t. In this embodiment, the multiple positive electrode tabs 22t protrude further in the winding axis direction WD than the separator 23. The multiple positive electrode tabs 22t are stacked at one end of the winding axis direction WD (upper end in Figure 5) to form a group of positive electrode tabs 25 (see Figure 2). Therefore, the height (length in the winding axis direction WD) and the width (length in the longitudinal direction LD) of each positive electrode tab 22t do not have to be the same. As shown in Figure 2, the first busbar 111 is joined to the group of positive electrode tabs 25.

[0025] As shown in Figure 5, the negative electrode 24 has a long, strip-shaped negative electrode current collector foil 24c (for example, copper foil) and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode current collector foil 24c. The constituent material of the negative electrode active material layer 24a may be any material used in this type of energy storage device (in this embodiment, a lithium-ion secondary battery) without any particular limitations.

[0026] Multiple negative electrode tabs 24t are provided at one end of the negative electrode current collector foil 24c in the winding axis direction WD (upper end in Figure 5). The multiple negative electrode tabs 24t protrude toward one end of the winding axis direction WD (upper end in Figure 5). The multiple negative electrode tabs 24t are provided at intervals (intermittently) along the longitudinal direction LD of the negative electrode 24. The negative electrode tabs 24t are part of the negative electrode current collector foil 24c and are portions of the negative electrode current collector foil 24c where the negative electrode active material layer 24a is not formed (unactive material layer formed portion). In this embodiment, the multiple negative electrode tabs 24t protrude further in the winding axis direction WD than the separator 23. For example, the multiple negative electrode tabs 24t are stacked at one end of the winding axis direction WD (upper end in Figure 5) to form a negative electrode tab group 27 (see Figure 2). Therefore, the height (length in the winding axis direction WD) and the width (length in the longitudinal direction LD) of each negative electrode tab 24t do not have to be the same. As shown in Figure 2, the second busbar 112 is joined to the group of negative electrode tabs 27.

[0027] The separator 23 is a component that insulates the positive electrode active material layer 22a of the positive electrode 22 from the negative electrode active material layer 24a of the negative electrode 24. In this embodiment, the separator 23 constitutes the outer surface of the electrode body 20. As the separator 23, for example, a porous sheet made of polyolefin resin such as polyethylene (PE) or polypropylene (PP) is used.

[0028] As shown in Figure 5, in the electrode body 20, the lower end P3 of the separator 23 is at the bottom, followed by the lower end P2 of the negative electrode 24, and the lower end P1 of the positive electrode 22 is at the top. The width of each sheet (in Figure 5, the length in the winding axis direction WD, excluding the positive electrode tab 22t and the negative electrode tab 24t) is largest for the separator 23, the negative electrode 24, and the positive electrode 22, in that order.

[0029] The electrolyte solution contains, for example, an electrolyte salt and a non-aqueous solvent. An example of an electrolyte salt is LiPF6. The concentration of the electrolyte salt in the electrolyte solution is, for example, 0.7 mol / L to 1.3 mol / L. The non-aqueous solvent may be, for example, a carbonate. Examples of carbonates include ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), monofluoroethylene carbonate (MFEC), difluoroethylene carbonate (DFEC), monofluoromethyldifluoromethyl carbonate (F-DMC), and trifluorodimethyl carbonate (TFDMC). These can be used individually or in combination of two or more.

[0030] Figures 6 and 7 are enlarged sections of Figure 3. Figure 6 schematically shows the connection structure between the positive electrode tab group 25, the first busbar 111, and the positive electrode current collector 150 in Figure 3. Figure 7 schematically shows the connection structure between the negative electrode tab group 27, the second busbar 112, and the negative electrode current collector 160 in Figure 3.

[0031] -Bus Bar 110- The busbar 110 is a member that connects two adjacent energy storage devices 1 in series in a first direction P, for example. In the embodiments shown in Figures 3, 6, and 7, the busbar 110 has a first busbar 111 and a second busbar 112. In this embodiment, the first busbar 111 and the second busbar 112 are joined to each other to form the busbar 110. The first busbar 111 and the second busbar 112 may be joined, for example, by ultrasonic bonding. The first busbar 111 is joined to a positive electrode tab group 25 or a positive electrode current collector 150. The first busbar 111 may be made of, for example, aluminum or an aluminum alloy. The second busbar 112 is joined here to a negative electrode tab group 27 or a negative electrode current collector 160. The second busbar 112 may be made of, for example, copper or a copper alloy. The means for joining the first busbar 111 and the positive electrode tab group 25, and the means for joining the second busbar 112 and the negative electrode tab group 27 are not particularly limited, and conventionally known joining methods such as ultrasonic bonding, laser welding, and resistance welding can be used. By using the busbar 110 having the above configuration, for example, the series connection structure of the energy storage devices 1 can be made more compact, which in turn can contribute to saving space inside the case 120. Conventionally, when connecting energy storage devices, each containing one electrode body, in series, at least three components are required: internal terminals, external terminals, and a busbar. On the other hand, with the above configuration, series connection can be made with just one busbar 110. Therefore, energy storage devices 1 can be connected in series with the minimum number of components, which in turn can reduce resistance.

[0032] In this embodiment, the first busbar 111 is L-shaped and has a first connecting portion 111a and a second connecting portion 111b. The first connecting portion 111a is flat and is joined to the positive electrode tab group 25. The second connecting portion 111b is joined to the second busbar 112 or the positive electrode current collector member 150. In this embodiment, the second busbar 112 is L-shaped and has a first connecting portion 112a and a second connecting portion 112b. The first connecting portion 112a is flat and is joined to the negative electrode tab group 27. The second connecting portion 112b is joined to the first busbar 111 or the negative electrode current collector member 160.

[0033] -Case 120- The case 120 is a hexahedral (rectangular) member that houses, for example, multiple energy storage devices 1 and multiple busbars 110 together. As shown in Figure 1, the case 120 comprises a case body 121 and a sealing plate 122. The case body 121 is the main body of the case 120, which houses, for example, multiple energy storage devices 1 and multiple busbars 110 inside. As shown in Figures 1 and 2, the case 120 has an opening 121h, a first surface 121a, a pair of opposing second surfaces 121b, 121c, and a pair of opposing third surfaces 121d, 121e. In this embodiment, the first surface 121a is the widest rectangular surface of the six surfaces of the case 120 and faces the opening 121h. The pair of second surfaces 121b, 121c extend from a pair of opposing long sides of the first surface 121a. As shown in Figure 1, the lower second surface 121c constitutes the bottom surface of the case 120. The upper second surface 121b is the top surface opposite to this bottom surface and is the mounting surface for the electrode terminals. The pair of third surfaces 121d and 121e extend from the pair of opposing short sides of the first surface 121a. In this specification, "rectangular" includes shapes in which straight long sides and short sides are joined to each other via curves, shapes in which at least one of the long sides and short sides is not straight but curved, uneven, or bent and composed of multiple straight or curved lines, etc.

[0034] The opening 121h is, for example, the area where the sealing plate 122 is fitted. Here, the opening 121h is formed by being surrounded by the upper edges of a pair of second surfaces 121b, 121c and the upper edges of a pair of third surfaces 121d, 121e, and is a wide rectangle. As shown in Figure 2, the opening 121h is provided with a recessed step 121s along its inner edge. Here, the sealing plate 122 is fitted into the step 121s. Furthermore, by joining (for example, welding) the sealing plate 122 to the step 121s, the case body 121 and the sealing plate 122 are integrated, and the case 120 is airtightly sealed.

[0035] In the configuration shown in Figure 2, the first surface 121a has an edge portion 123 and an overhang portion 124. The edge portion 123 is, for example, a portion provided along the periphery of the first surface 121a. The overhang portion 124 is, for example, a portion that extends from the edge portion 123 of the first surface 121a toward the interior of the case body 121. The shape of the overhang portion 124 is the same as the overhang portion 127 provided on the sealing plate 122, which will be described later, so its description is omitted here. Because the first surface 121a has an overhang portion 124, when the energy storage device 1 is housed in the case 120, restraining pressure can be applied to the wide surface 1a of the energy storage device 1. Therefore, there is no need to separately prepare other members to restrain the energy storage device 1.

[0036] As shown in Figure 1, the second surface 121b is provided with a discharge valve 125, a first mounting hole 128, and a second mounting hole 129 (see Figure 2). The discharge valve 125 is, for example, a thin-walled portion. Here, the discharge valve 125 is configured to rupture when the pressure inside the case 120 exceeds a predetermined value, thereby discharging the gas inside the case 120 to the outside. The first mounting hole 128 is, for example, a through hole through which the positive electrode terminal 130 is inserted. The second mounting hole 129 is, for example, a through hole through which the negative electrode terminal 140 is inserted.

[0037] The sealing plate 122 is, for example, a flat plate-shaped member that seals the opening 121h. Therefore, the shape of the sealing plate 122 is preferably such that it corresponds to the shape of the opening 121h. In this embodiment, the sealing plate 122 is a wide rectangle. Here, when the sealing plate 122 is attached to the opening 121h, the sealing plate 122 faces the first surface 121a. In this embodiment, the sealing plate 122 is placed opposite the bottom of the step 121s (see Figure 2).

[0038] In the configurations shown in Figures 1 and 2, the sealing plate 122 has an edge portion 126 and an overhang portion 127. The edge portion 126 is, for example, a portion provided along the periphery of the sealing plate 122. The overhang portion 127 is, in this case, a portion of the sealing plate 122 that extends from the edge portion 126 toward the interior of the case body 121. For example, the overhang portion 127 has a pair of opposing short side walls 127a, a pair of opposing long side walls 127b, and a flat surface 127c. As shown in Figure 1, the short side walls 127a extend from the edge portion 126 toward the interior of the case body 121 along a pair of opposing short sides of the sealing plate 122. The long side walls 127b also extend from the edge portion 126 toward the interior of the case body 121 along a pair of opposing long sides of the sealing plate 122. The flat surface 127c is, in this case, surrounded by the tips of a pair of opposing short side walls 127a and the tips of a pair of opposing long side walls 127b. In the configurations shown in Figures 1 and 2, the flat surface 127c faces, for example, the wide surface 1a of the energy storage device 1. The sealing plate 122 has an overhang 127, which allows the energy storage device 1 to be housed in the case 120, thereby applying restraining pressure to the wide surface 1a of the energy storage device 1. This eliminates the need to separately provide other members for restraining the energy storage device 1. From the viewpoint of efficiently applying pressing force to the energy storage device 1, when the area of ​​the wide surface 1a is set to 1, the area of ​​the flat surface 127c is, for example, 0.7 or more, preferably 0.8 or more, more preferably 0.9 or more, and is not particularly limited, but may be 1.3 or less, 1.2 or less, or 1.1 or less. In this embodiment, protruding portions (protruding portion 124 or protruding portion 127) are provided on both the first surface 121a and the sealing plate 122, but in other embodiments, such portions may be provided only on the first surface 121a or only on the sealing plate 122.

[0039] In the configuration shown in Figure 1, both the positive terminal 130 and the negative terminal 140 are provided on one of the sides of the case 120 sandwiched between the first surface 121a and the sealing plate 122 (here, the second surface 121b, 121c and the third surface 121d, 121e). This allows for a simpler current collection structure for the energy storage module 100. As a result, it becomes easier to reduce the weight of the energy storage module 100.

[0040] -Positive terminal 130- Figure 8 is a perspective view of the positive terminal 130. The positive terminal 130 is a component that is electrically connected to, for example, other energy storage modules, devices, etc., and is also electrically connected to the positive terminals of multiple energy storage devices 1 in a series-connected case 120. The positive terminal 130 may be made of, for example, aluminum or an aluminum alloy.

[0041] As shown in Figure 8, the positive electrode terminal 130 has a first conductive part 131 and a second conductive part 132. The first conductive part 131 is an example of a "positive electrode outer conductive part," and the description of "first conductive part 131" in this specification may be read as "positive electrode outer conductive part 131" as needed. The second conductive part 132 is an example of a "positive electrode inner conductive part," and the description of "second conductive part 132" in this specification may be read as "positive electrode inner conductive part 132" as needed.

[0042] The first conductive portion 131 is, for example, a part located on the outside of the case body 121. In the configuration shown in Figure 1, the first conductive portion 131 is rectangular and flat, and is positioned along the second surface 121b. Furthermore, the first conductive portion 131 is positioned towards the right side in the direction of the long side of the second surface 121b. The first conductive portion 131 is used, for example, to connect the energy storage module 100 to other energy storage modules 100, devices, etc.

[0043] The second conductive portion 132 is located inside the case body 121, accessible from the first conductive portion 131 through the first mounting hole 128. The second conductive portion 132 is also connected to the positive electrode tab 22t (in this case, the group of positive electrode tabs 25) of the energy storage device 1 at one end in the first direction P (in this case, the energy storage device 1 closest to the viewer in Figure 2).

[0044] In this embodiment, the second conductive portion 132 is an L-shaped portion. As shown in Figure 8, the second conductive portion 132 has an insertion portion 132a and an extension portion 132b. The insertion portion 132a is the portion that is inserted into the first mounting hole 128. As shown in Figure 8, the insertion portion 132a is flat and extends approximately perpendicularly (90 degrees ± 10 degrees) from the outer edge of the first conductive portion 131. The extension portion 132b is the portion that connects to, for example, the positive electrode tab 22t (here, the group of positive electrode tabs 25) provided on the energy storage device 1 at one end in the first direction P (here, the energy storage device 1 closest to the viewer in Figure 2). In this embodiment, the extension portion 132b and the group of positive electrode tabs 25 are connected via a joint with the positive electrode current collector 150 (see Figure 6). The extended portion 132b and the positive electrode current collector member 150 are joined by conventionally known means such as ultrasonic bonding, laser welding, or resistance welding. Here, the extended portion 132b extends along the second surface 121b inside the case body 121. As shown in Figure 8, the extended portion 132b is flat, approximately perpendicular to the insertion portion 132a, and extends in a direction that does not overlap with the first conductive portion 131 (in Figure 8, in the opposite direction to the first conductive portion 131).

[0045] -Negative terminal 140- Figure 9 is a perspective view of the negative terminal 140. The negative terminal 140 is a component that is electrically connected to, for example, other energy storage modules, devices, etc., and is also electrically connected to the negative terminals of multiple energy storage devices 1 in a series-connected case 120. The negative terminal 140 may be made of, for example, copper or a copper alloy.

[0046] As shown in Figure 9, the negative electrode terminal 140 has a first conductive part 141 and a second conductive part 142. The first conductive part 141 is an example of a "negative electrode outer conductive part," and the description of "first conductive part 141" in this specification may be read as "negative electrode outer conductive part 141" as needed. The second conductive part 142 is an example of a "negative electrode inner conductive part," and the description of "second conductive part 142" in this specification may be read as "negative electrode inner conductive part 142" as needed.

[0047] The first conductive portion 141 is, for example, a part located on the outside of the case body 121. In the configuration shown in Figure 1, the first conductive portion 141 is rectangular and flat, and is positioned along the second surface 121b. Furthermore, the first conductive portion 141 is positioned towards the left side in the direction of the long side of the second surface 121b. The first conductive portion 141 is used, for example, to connect the energy storage module 100 to other energy storage modules 100, devices, etc.

[0048] The second conductive portion 142 is located inside the case body 121, accessible from the first conductive portion 141 through the second mounting hole 129. The second conductive portion 142 is also connected to the negative electrode tab 24t (here, the negative electrode tab group 27) of the other end of the energy storage device 1 in the first direction P (here, the rearmost energy storage device 1 in Figure 2).

[0049] In this embodiment, the second conductive portion 142 is an L-shaped portion. As shown in Figure 9, the second conductive portion 142 has an insertion portion 142a and an extension portion 142b. The insertion portion 142a is the portion that is inserted into the second mounting hole 129. As shown in Figure 9, the insertion portion 142a is flat and extends substantially perpendicularly from the outer edge of the first conductive portion 141. The extension portion 142b is the portion that connects to, for example, the negative electrode tab 24t (here, the group of negative electrode tabs 27) provided on the energy storage device 1 at one end in the first direction P (here, the rearmost energy storage device 1 in Figure 2). In this embodiment, the extension portion 142b and the group of negative electrode tabs 27 are connected via a joint with the negative electrode current collector 160 (see Figures 2 and 7). The extended portion 142b and the negative electrode current collector member 160 are joined by conventionally known means such as ultrasonic bonding, laser welding, or resistance welding. Here, the extended portion 142b extends along the second surface 121b inside the case body 121. As shown in Figure 9, the extended portion 142b is flat, approximately perpendicular to the insertion portion 142a, and extends in a direction that does not overlap with the first conductive portion 141 (in Figure 9, the direction opposite to the first conductive portion 141).

[0050] As described above, the positive terminal 130 and the negative terminal 140 have almost the same shape. However, as shown in Figures 8 and 9, and also referring to Figure 1, the way in which the insertion portion 132a is attached to the first conductive portion 131 of the positive terminal 130 is different from the way in which the insertion portion 142a is attached to the first conductive portion 141 of the negative terminal 140. In this embodiment, the insertion portion 132a of the positive terminal 130 extends from the left side of the long side in front of the first conductive portion 131. Also, the insertion portion 142a of the negative terminal 140 extends from the right side of the long side in front of the first conductive portion 141.

[0051] -Positive electrode current collector 150- The positive electrode current collector 150 is, for example, a member that electrically connects the positive electrode tab group 25 and the positive electrode terminal 130. As shown in Figure 6, the positive electrode current collector 150 has a base portion 151 and an upright portion 152. The base portion 151 is, for example, the portion that is joined to the first bus bar 111. In this embodiment, the base portion 151 is flat and is arranged along the positive electrode tab group 25 side of the second connection portion 111b of the first bus bar 111. The upright portion 152 is, for example, the portion that is joined to the extended portion 132b of the positive electrode terminal 130. In this embodiment, the upright portion 152 is flat and is erected substantially vertically from the outer edge of the base portion 151. In this embodiment, the tip of the extended portion 132b is connected to the upper end of the upright portion 152. The positive electrode current collector 150 is made of, for example, aluminum or an aluminum alloy.

[0052] -Negative electrode current collector 160- The negative electrode current collector 160 is, for example, a member that electrically connects the negative electrode tab group 27 and the negative electrode terminal 140. As shown in Figure 7, the negative electrode current collector 160 has a first base portion 161, a second base portion 162, and an upright portion 163. The first base portion 161 is, for example, the portion that is joined to the second bus bar 112. In this embodiment, the first base portion 161 is flat and is arranged along the negative electrode tab group 27 side of the second connection portion 112b of the second bus bar 112. The second base portion 162 is, for example, a portion that extends from the first base portion 161. In this embodiment, the second base portion 162 is flat and extends from the first base portion 161 along the upper surfaces of a plurality of energy storage devices 1 arranged in a first direction P from the rearmost energy storage device 1 to the frontmost energy storage device 1. The upright portion 163 is, for example, the portion that is joined to the extended portion 142b of the negative electrode terminal. In this embodiment, the upright portion 163 is flat and rises substantially vertically from the outer edge of the tip of the second base portion 162. As shown in Figure 2, the tip of the extended portion 142b is connected to the upper end of the upright portion 163. The negative electrode current collector member 160 is made of, for example, copper or a copper alloy.

[0053] -Insulating material 170- The insulating member 170 is, for example, a member that insulates the case body 121 from the electrode terminals. Here, the insulating member 170 is positioned on the outside of the case body 121 between the first conductive portion 141 of the positive electrode terminal 130 and the second surface 121b, and between the first conductive portion 141 of the negative electrode terminal 140 and the second surface 121b. The insulating member 170 is also positioned between the insertion portion 132a of the positive electrode terminal 130 and the first mounting hole 128, and between the insertion portion 142a of the negative electrode terminal 140 and the second mounting hole 129. Furthermore, the insulating member 170 is positioned on the inside of the case body 121 between a part of the extended portion 132b of the positive electrode terminal 130 and the second surface 121b, and between a part of the extended portion 142b of the negative electrode terminal 140 and the second surface 121b. The insulating member 170 may consist of a single member or be composed of a combination of multiple members. The insulating member 170 may be an insulating member made of a resin material used in this type of application.

[0054] The energy storage module 100 can be used for various purposes, but it is particularly suitable for use as a power source (driving power supply) for motors mounted on vehicles such as passenger cars and trucks. The type of vehicle is not particularly limited, but preferred examples include plug-in hybrid vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs).

[0055] As described above, the energy storage module 100 comprises a plurality of energy storage devices 1, a plurality of busbars 110, a case 120, a positive terminal 130, and a negative terminal 140. The plurality of energy storage devices 1 are equipped with a positive tab 22t and a negative tab 24t, and have a pair of wide surfaces 1a. The plurality of energy storage devices 1 are arranged in a first direction P with their wide surfaces 1a facing each other. The plurality of busbars 110 connect two adjacent energy storage devices 1 in series in the first direction P. The case 120 is a hexahedral case that houses both the plurality of energy storage devices 1 and the plurality of busbars 110. The case 120 also comprises a case body 121 having the widest of the six surfaces, the first surface 121a, and an opening 121h facing the first surface 121a, and a sealing plate 122 that seals the opening 121h, with a shape corresponding to the shape of the opening 121h. The positive terminal 130 and the negative terminal 140 are attached to the case body 121. Inside the case 120, a plurality of energy storage devices 1 are sandwiched between the first surface 121a and the sealing plate 122, arranged in a first direction P. The positive terminal 130 has a positive outer conductive part 131 (first conductive part 131) and a positive inner conductive part 132 (second conductive part). The positive outer conductive part 131 is located on the outside of the case body 121. The positive inner conductive part 132 is located on the inside of the case body 121, passing through a first mounting hole 128 provided in the case body 121 from the positive outer conductive part 131. The positive inner conductive part 132 is connected to the positive tab 22t of the energy storage device 1 at one end in the first direction P (the closest energy storage device 1 in Figure 2). Furthermore, the negative electrode terminal 140 has a negative electrode outer conductive portion 141 (first conductive portion 141) and a negative electrode inner conductive portion 142 (second conductive portion 142). The negative electrode outer conductive portion 141 is located on the outside of the case body 121. The negative electrode inner conductive portion 142 is located on the inside of the case body 121, passing through a second mounting hole 129 provided in the case body 121 from the negative electrode outer conductive portion 141. The negative electrode inner conductive portion 142 is connected to the negative electrode tab 24t of the other end of the energy storage device 1 in the first direction P (the rearmost energy storage device 1 in Figure 2).

[0056] In the energy storage module 100, multiple energy storage devices 1 are connected in series, resulting in a high voltage. Furthermore, since the multiple energy storage devices 1 are housed in the case 120 in a series configuration, the external structure of the energy storage devices 1 can be simplified. This allows for a lighter energy storage module 100 with a high voltage. In addition, because the energy storage devices 1 can be connected in series with the minimum number of components inside the case 120, resistance can be reduced.

[0057] As described above, specific embodiments of the technology disclosed herein include those described in the following sections. Section 1: It is an energy storage module, A plurality of energy storage devices having a positive electrode tab and a negative electrode tab, and a pair of wide surfaces, wherein the plurality of energy storage devices are arranged in a first direction with the wide surfaces facing each other, Multiple busbars connecting two adjacent energy storage devices in series in the first direction, A case having a hexahedral shape for housing the plurality of energy storage devices and the plurality of busbars, the case having a case body having the widest first face among the six faces and an opening facing the first face, and a sealing plate having a shape corresponding to the shape of the opening for sealing the opening, The positive terminal and negative terminal attached to the case body, Equipped with, Within the case, the plurality of energy storage devices, arranged in a first direction, are sandwiched between the first surface and the sealing plate. The aforementioned positive terminal is, The case body has a positive electrode outer conductive portion located on the outside of the case body, and a positive electrode inner conductive portion located on the inside of the case body, accessible from the positive electrode outer conductive portion through a first mounting hole provided in the case body. The positive electrode inner conductive portion is connected to the positive electrode tab of the energy storage device at one end in the first direction, The aforementioned negative terminal is The case body has an outer negative electrode conductive portion located on the outside of the case body, and an inner negative electrode conductive portion located on the inside of the case body, accessible through a second mounting hole provided in the case body from the outer negative electrode conductive portion. A power storage module in which the inner conductive portion of the negative electrode is connected to the negative electrode tab of the power storage device at the other end in the first direction. Section 2: The energy storage module according to item 1, wherein both the positive terminal and the negative terminal are provided on one of the sides of the case sandwiched between the first surface and the sealing plate. Section 3: The energy storage module according to claim 1 or 2, wherein the plurality of energy storage devices comprises electrode bodies and an outer casing made of a resin film that houses the electrode bodies. Section 4: The energy storage module according to any one of claims 1 to 3, wherein at least one of the sealing plate and the first surface has a protruding portion that extends toward the interior of the case body.

[0058] While embodiments of the technology disclosed herein have been described above, the technology disclosed herein is not intended to be limited to the embodiments described herein. The technology disclosed herein can also be implemented in other embodiments. The technology described in the claims includes various modifications and changes to the embodiments exemplified above. For example, it is possible to replace parts of the above embodiments with other modifications, and it is also possible to add other modifications to the above embodiments. Furthermore, if a technical feature is not described as essential, it may be deleted as appropriate. [Explanation of symbols]

[0059] 1. Energy storage device 1a Wide surface 25 Positive electrode tab group 27 Negative electrode tab group 100 Energy Storage Modules 110 Bus Bar 120 cases 130 Positive terminal 140 Negative terminal 150 Positive electrode current collector 160 Negative electrode current collector 170 Insulating material P 1st direction

Claims

1. It is an energy storage module, A plurality of energy storage devices having a pair of wide surfaces, along with an electrode body having a positive electrode tab and a negative electrode tab, wherein the plurality of energy storage devices are arranged in a first direction with the wide surfaces facing each other, Multiple busbars connecting two adjacent energy storage devices in series in the first direction, A case having a hexahedral shape for housing the plurality of energy storage devices and the plurality of busbars, the case having a case body having the widest first face among the six faces and an opening facing the first face, and a sealing plate having a shape corresponding to the shape of the opening for sealing the opening, The positive terminal and negative terminal attached to the case body, A positive electrode current collector member electrically connects the positive electrode tab and the positive electrode terminal, A negative electrode current collector member electrically connects the negative electrode tab and the negative electrode terminal, Equipped with, The plurality of busbars include a first busbar connected to the positive electrode tab and a second busbar connected to the negative electrode tab. The first busbar and the second busbar are connected to each other. Within the case, the plurality of energy storage devices arranged in a first direction are sandwiched between the first surface and the sealing plate. The aforementioned positive terminal is The case body has a positive electrode outer conductive portion located on the outside of the case body, and a positive electrode inner conductive portion located on the inside of the case body, accessible from the positive electrode outer conductive portion through a first mounting hole provided in the case body. In the positive electrode inner conductive portion, the positive electrode current collector member and the first busbar connected to the energy storage device at one end in the first direction are connected to the positive electrode tab provided on the energy storage device at that end. The aforementioned negative terminal is The case body has an outer negative electrode conductive portion located on the outside of the case body, and an inner negative electrode conductive portion located on the inside of the case body, accessible through a second mounting hole provided in the case body from the outer negative electrode conductive portion. In the inner conductive portion of the negative electrode, the negative electrode current collector member is connected to the negative electrode tab provided on the energy storage device at the other end via the second busbar connected to the energy storage device at the other end in the first direction. Both the positive terminal and the negative terminal are provided on one of the sides of the case sandwiched between the first surface and the sealing plate. The electrode body is provided with a positive electrode tab and a negative electrode tab on a first end face facing the side surface on which the positive electrode terminal and the negative electrode terminal are provided. The positive electrode inner conductive portion and the negative electrode inner conductive portion are, An insertion portion inserted into the first mounting hole or the second mounting hole, From the insertion portion, along the side surface where the positive terminal and the negative terminal are provided, there is an extended portion that extends in the direction from the other end of the energy storage device toward the one end of the energy storage device in the first direction. It includes, The positive electrode current collector member is A flat base portion is joined to the first busbar connected to the energy storage device at one end in the first direction, A flat plate-shaped upright portion is erected from the base portion and joined to the extended portion of the positive electrode inner conductive portion. It is equipped with, The aforementioned negative electrode current collector member is A flat plate-shaped first base portion is joined to the second busbar connected to the energy storage device at the other end in the first direction, A flat plate-shaped second base portion extends from the first base portion in the direction from the energy storage device at the other end toward the energy storage device at the one end in the first direction, A flat plate-shaped upright portion is erected from the second base portion and joined to the extended portion of the negative electrode inner conductive portion. It is equipped with Energy storage module.

2. The energy storage module according to claim 1, wherein the plurality of energy storage devices are equipped with an outer casing made of a resin film that houses the electrode bodies.

3. The energy storage module according to claim 1 or 2, wherein at least one of the sealing plate and the first surface has a protruding portion that extends toward the interior of the case body.

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