Battery pack

Abstract

A battery pack is provided with: a battery provided with a lid as an external terminal for sealing a body on one side in the Z direction; a first holder that holds one side in the Z direction of the plurality of batteries arranged side by side, and that has an opening that exposes the lid; and a collector plate that comes into contact with one surface of the first holder at the contact portion and is connected to the cover exposed from the opening, the collector plate protruding from the contact portion to one side in the longitudinal direction, closing a part of the opening and being connected to the cover. A portion of the collector plate that closes a portion of the opening protrudes to a position closer to one side than a surface on one side of the Z direction of the first holder, thereby forming a space among the contact portion, the portion of the collector plate that closes the portion of the opening, and the cover.

Description

Technical Field

[0001] The present invention relates to a battery pack accommodating a plurality of batteries. Background Art

[0002] In a battery pack, a plurality of batteries are housed in an outer casing in a manner corresponding to a device in which the batteries are used. In a battery pack, a plurality of batteries arranged in a row are held by a holder, and the plurality of batteries are electrically connected to each other by a current collector plate (for example, Patent Document 1).

[0003] When a battery stored in a battery pack goes into thermal runaway due to some abnormality, the high-temperature internal gas discharged from the battery in thermal runaway comes into contact with the batteries held in the same holder (hereinafter referred to as peripheral batteries), which may cause the peripheral batteries to go into thermal runaway and cause a chain reaction of thermal runaway. Therefore, it is necessary to reliably discharge the internal gas discharged from the battery in thermal runaway to the outside of the holder without contacting the peripheral batteries.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-002199 Summary of the invention

[0007] In addition, in the battery, a gas discharge valve is provided on one side in the longitudinal direction. With this structure, when thermal runaway occurs, the internal pressure of the battery rises and the gas discharge valve operates to discharge the internal gas from one side in the longitudinal direction. On the other hand, there is a case where an external terminal is provided on one side in the longitudinal direction of the battery. Therefore, an opening for exposing the external terminal is provided in a retaining frame that holds one side in the longitudinal direction of the battery, and a collector lead of a collector plate is connected to the external terminal exposed from the opening.

[0008] In the above structure, when the internal gas of the battery is exhausted, the internal gas is exhausted from the opening of the holder. However, since the collector lead of the collector plate blocks part of the opening, there is a case where part of the exhaust gas is blocked by the collector lead. In recent years, due to the large-scale and high-output batteries, the wide-width collector leads have increased, and the above tendency has become more obvious.

[0009] When the discharge of internal gas is blocked by the current collecting lead, the discharge of internal gas to the outside of the holder is hindered, and the high-temperature internal gas flows into the inside of the holder and contacts the surrounding batteries, which may cause thermal runaway of the surrounding batteries, thereby causing a chain reaction of thermal runaway.

[0010] Therefore, an object of the present invention is to provide a battery pack capable of reliably discharging high-temperature internal gas discharged from a battery to the outside of a holder when the battery thermally runs away.

[0011] The battery pack of the present invention is characterized in that it comprises: a battery having an external terminal on one side in the length direction, and the battery discharges internal gas from one side in the length direction when the internal pressure rises; a retaining frame, which retains a plurality of batteries arranged in an arranged manner on one side in the length direction and has an opening for exposing the external terminal; and a collector plate, which has an abutting portion abutting against a surface on one side of the retaining frame, the collector plate blocks a part of the opening and is connected to the external terminal, the collector plate protrudes from the abutting portion to one side in the length direction, blocks a part of the opening and is connected to the external terminal, and a part of the collector plate that blocks the opening protrudes to a position closer to one side than a surface on one side in the length direction of the retaining frame, thereby forming a space between the abutting portion, the part of the collector plate that blocks the opening, and the external terminal.

[0012] According to the battery pack of the present invention, when the battery thermally runs away, the high-temperature internal gas exhausted from the battery can be reliably exhausted to the outside of the holder. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing a battery pack as an example of an embodiment.

[0014] Figure 2 It is a cross-sectional view showing a battery pack as an example of an embodiment.

[0015] Figure 3 It is a cross-sectional view showing a battery as an example of an embodiment.

[0016] Figure 4 It is a perspective view showing a current collector plate as an example of an embodiment.

[0017] Figure 5 It is a side view showing a current collector plate as an example of an embodiment.

[0018] Figure 6 It is a side view showing a current collector plate as another example of the embodiment.

[0019] Figure 7 It is a side view showing a current collector plate as still another example of the embodiment.

[0020] Figure 8 It is a side view showing a current collector plate as still another example of the embodiment. DETAILED DESCRIPTION

[0021] In the following description, specific shapes, materials, directions, numerical values, etc. are given for easy understanding of the present invention and can be appropriately changed according to the application, purpose, specification, etc.

[0022] <Battery Pack>

[0023] use Figure 1 A battery pack 10 as an example of the embodiment will be described.

[0024] In the battery pack 10, a plurality of battery modules 20 are housed in an outer casing 11 in a manner corresponding to the device to be used. In each battery module 20, a plurality of (in Figure 1 In the example shown, two batteries 30 are fixed to each other by a holder and housed in an outer casing 11. With the battery pack 10, when the battery 30 thermally runs away, the high-temperature internal gas discharged from the battery 30 can be reliably discharged to the outside of the holder, as will be described in detail later.

[0025] Hereinafter, the components will be described with the longitudinal direction of the battery 30 being the Z direction, the direction perpendicular to the Z direction and in which the battery 30 is arranged in the battery module 20 being the X direction, and the direction perpendicular to the Z direction and the X direction being the Y direction. Figure 3 ) of the top plate, that is, the cover 45 (refer to Figure 3 ) is set as one side, and the side opposite thereto is set as the other side.

[0026] The battery pack 10 is mainly used as a power source for power. For example, the battery pack 10 is used as a power source for electric devices driven by motors, such as electric vehicles, electric tools, electric power-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the use of the battery pack 10 is not specific, and it can also be used as a power source for various electric devices used indoors and outdoors, such as cleaners, wireless devices, lighting devices, digital cameras, and video cameras, etc., other than electric devices.

[0027] The battery pack 10 has a plurality of Figure 1 In the example shown, there are two battery modules 20 each including a battery 30 and an outer casing 11 that accommodates the plurality of battery modules 20 .

[0028] The battery module 20 has a plurality of batteries 30 which will be described in detail later and arranged in an array. Figure 1 In the example shown, three battery modules 20 are connected in series, and a voltage corresponding to the device used is output. In the battery module 20, a plurality of batteries 30 are connected in parallel. The battery module 20 will be described in detail later.

[0029] The outer casing 11 is made of a metal such as aluminum and is cylindrical. However, the outer casing 11 is not limited to being made of metal and may be made of resin. A battery pack external terminal 12 electrically connected to the battery module 20 is provided at the end on the other side of the outer casing 11 in the Z direction. When the battery pack 10 is assembled in a device that carries the battery pack 10 and is used, the battery pack external terminal 12 is used as a terminal for supplying a DC voltage. The battery pack external terminal 12 is also used when charging the battery pack 10. In addition, an exhaust hole 13 is provided on the side of the outer casing 11 (see Figure 2 ), the exhaust hole 13 discharges the high-temperature internal gas discharged from the battery 30 in thermal runaway to the outside of the battery pack 10.

[0030] <Battery Module>

[0031] use Figure 2 A battery module 20 as an example of the embodiment will be described.

[0032] The battery module 20 includes: two batteries 30; a first holder 50, which is a holder on one side of the Z direction for holding the two batteries 30; a collector plate 60, which is in contact with a surface of one side of the first holder 50 and is in contact with a sealing body 36 (see Figure 3 ) is connected to the top plate, that is, the cover 45; a second holder 55, which holds the other side of the two batteries 30 in the Z direction; and a collector lead 69, which is connected to the outer can 35 (reference Figure 3 ) is connected to the bottom of the battery pack 10. Among the plurality of battery modules 20 connected in series in the battery pack 10, the current collector plate 60 of the battery module 20 closest to one side in the Z direction corresponds to the total positive, and the current collector lead 69 of the battery module 20 closest to the other side in the Z direction corresponds to the total negative, and is electrically connected to the battery pack external terminal 12 (not shown). The battery 30, the first holder 50, and the current collector plate 60 will be described in detail later.

[0033] <Battery>

[0034] use Figure 2 and Figure 3 A battery 30 as an example of an embodiment will be described.

[0035] The battery 30 is a cylindrical battery and a lithium ion battery. However, the battery 30 is not limited to a cylindrical battery, and may be a square battery, a stacked battery, etc. In addition, the battery 30 may be an aqueous battery or a non-aqueous battery. As an example of a non-aqueous battery, a lithium ion battery is preferably used.

[0036] like Figure 3As shown, the battery 30 is provided with a top plate of the sealing body 36, i.e., a cover 45, which serves as a positive electrode external terminal, on one side in the Z direction. When the internal pressure rises during thermal runaway, the internal gas is discharged from the exhaust hole 45A of the cover 45, which will be described in detail later. In other words, in the battery 30, the internal gas is discharged from one side in the Z direction when the internal pressure rises.

[0037] The battery 30 includes an electrode body 34, an electrolyte (not shown), and an outer can 35 for storing the electrode body 34 and the electrolyte. The electrode body 34 includes a positive electrode 31, a negative electrode 32, and a separator 33, and has a winding structure in which the positive electrode 31 and the negative electrode 32 are wound in a spiral shape with the separator 33 interposed therebetween. The outer can 35 has a bottomed cylindrical shape with one side open in the Z direction, and the opening of the outer can 35 is sealed by a sealing body 36.

[0038] The battery 30 includes insulating plates 37 and 38 disposed above and below the electrode body 34, respectively. Figure 3 In the example shown, the positive electrode lead 39 attached to the positive electrode 31 extends to the sealing body 36 side through the through hole of the insulating plate 37, and the negative electrode lead 40 attached to the negative electrode 32 extends from the outside of the insulating plate 38 to the bottom side of the outer can 35. The positive electrode lead 39 is connected to the bottom plate of the sealing body 36, that is, the lower surface of the internal terminal plate 41, by welding or the like, and the top plate of the sealing body 36, that is, the cover 45, which is electrically connected to the internal terminal plate 41, serves as the positive electrode external terminal. The negative electrode lead 40 is connected to the bottom inner surface of the outer can 35 by welding or the like, and the bottom of the outer can 35 serves as the negative electrode external terminal.

[0039] The sealing body 36 has a structure in which an internal terminal plate 41, a lower valve body 42, an insulating member 43, an upper valve body 44, and a cover 45 are stacked in order from the electrode body 34 side. The components constituting the sealing body 36 are, for example, disc-shaped or ring-shaped, and the components except the insulating member 43 are electrically connected to each other. The lower valve body 42 and the upper valve body 44 constituting the so-called gas exhaust valve are connected to each other at their respective central portions, and the insulating member 43 is interposed between their respective peripheral portions.

[0040] In the gas discharge valve, if the internal pressure rises when the battery 30 thermally runs away, the lower valve body 42 is deformed and broken in a manner that pushes the upper valve body 44 toward the cover 45 side, and the current path between the lower valve body 42 and the upper valve body 44 is cut off. If the internal pressure rises further, the upper valve body 44 breaks, and the internal gas is discharged from the exhaust hole 45A formed on the side of the convex part of the cover 45. However, this embodiment is not limited to this, and a structure in which a gas discharge valve is provided on the other side in the Z direction, that is, the bottom of the outer tank 35, and the internal gas is discharged from the other side in the Z direction when the internal pressure rises.

[0041] <Retainer>

[0042] use Figure 2 and Figure 4 The first holder 50 as an example of the embodiment will be described.

[0043] As described above, the first holding frame 50 holds one side in the Z direction of the two batteries 30. However, the number of batteries held by the first holding frame 50 is not limited to the present embodiment.

[0044] The first holder 50 may be made of, for example, a highly thermally conductive PPS (polyphenylene sulfide) resin, a resin containing a heat dissipating filler, a thermosetting resin capable of injection molding, etc. More specifically, the first holder 50 may be made of a phenolic resin, an unsaturated polyester, or an unsaturated polyester mixed with a heat absorbent, etc. The first holder 50 may also be made of an inorganic mineral such as mica, or a material obtained by mixing an inorganic mineral such as mica into a resin material.

[0045] like Figure 4 As shown, the first holder 50 is formed into a rounded shape when viewed from the Z direction, and has a predetermined thickness in the Z direction. The first holder 50 has a storage portion 51 (see FIG. 5 ) for storing the battery 30. Figure 2 ) and an opening 52 that exposes the cover 45 serving as the positive terminal of the battery 30.

[0046] like Figure 2 As shown, the storage portion 51 is formed on the surface of the other side in the Z direction of the first holding frame 50. The storage portion 51 is formed to be circular when viewed from the other side in the Z direction and to be a recessed portion when viewed from the X direction or the Y direction. The end of one side in the Z direction of the battery 30 is fitted into the storage portion 51, and one side of the battery 30 is held.

[0047] like Figure 2 and Figure 4 As shown, the opening 52 is formed to penetrate the storage portion 51. In more detail, the opening 52 is formed as a circular hole with a diameter smaller than the diameter of the circular shape of the storage portion 51 when viewed from the other side in the Z direction. However, the center of the storage portion 51 and the center of the opening 52 are formed as the same center. By using the opening 52, the top plate of the sealing body 36, that is, the cover 45, which serves as the positive terminal of the battery 30, can be exposed, and the cover 45 and the collector plate 60 can be connected. In addition, by using the opening 52, when the battery 30 thermally runs away, the high-temperature gas discharged from the battery 30 can be discharged to the outside of the first retaining frame 50.

[0048] <Current collector>

[0049] use Figure 4 and Figure 5 The current collector plate 60 as an example of the embodiment will be described.

[0050] The collector plate 60 abuts against the surface of one side in the Z direction of the first holder 50 at the abutting portion 61, and is connected to the cover 45 serving as the positive external terminal of the battery 30. More specifically, the collector plate 60 connects the covers 45 serving as the positive terminals of the two batteries 30 held by the first holder 50 to each other. The collector plate 60 is made of a metal plate such as an aluminum plate or a copper plate.

[0051] The collector plate 60 blocks a portion of one side of the opening 52 in the Z direction to a joint portion 65 to be described later connected to the cover 45 in the opening 52 of the first holder 50. The portion of the collector plate 60 that blocks one side of the opening 52 in the Z direction is formed as a top plate portion 63 that protrudes to a position closer to one side than the surface on one side of the first holder 50 in the Z direction. In other words, the collector plate 60 straddles the edge of the cover 45 exposed from the opening 52 of the first holder 50 using the top plate portion 63 that protrudes to a position closer to one side than the surface on one side of the first holder 50 in the Z direction.

[0052] By setting such a structure, a space is formed between the contact portion 61, the top plate portion 63 and the cover 45. Therefore, compared with a conventional collector plate in which the top plate portion 63 protruding to one side in the Z direction is not formed, a larger space is formed between the edge portion of the cover 45 exposed from the opening 52 of the first holder 50 and the collector plate 60.

[0053] Thus, the internal gas of the battery 30 discharged from the opening 52 of the first holder 50 is easily discharged to the outside of the first holder 50 without contacting the battery 30 held inside the first holder 50. Thus, it is possible to avoid a situation where, when one battery 30 of the battery module 20 thermally runs away, the high-temperature internal gas flows into the first holder 50, and the high-temperature internal gas contacts other batteries 30 inside the first holder 50, causing other batteries 30 inside the first holder 50 to thermally run away, thereby preventing a chain reaction of thermal runaway.

[0054] More specifically, the current collector plate 60 has a contact portion 61, a rising portion 62, a top plate portion 63, an inclined portion 64, and a joint portion 65, which are described in detail below, from the surface of one side in the Z direction of the first holder 50 to the cap 45 as the positive terminal. In addition, generally speaking, the inclined portion 64 and the joint portion 65 are equivalent to the current collector lead.

[0055] The contact portion 61 is a portion that contacts one surface in the Z direction of the first holder 50. The contact portion 61 is preferably disposed in the center between the two openings 52. The rising portion 62 is a portion that protrudes from both ends of the contact portion 61 in the X direction toward one side in the Z direction.

[0056] The top plate portion 63 is a portion that spans the edge portion of the opening 52 of the first holder 50 and the edge portion of the cover 45 exposed from the opening 52 from the rising portion 62. The inclined portion 64 is a portion that is inclined from the top plate portion 63 toward a joining portion 65 described later and is connected to the joining portion 65. The joining portion 65 is a portion that is electrically connected to the central portion of the cover 45 by, for example, welding.

[0057] In addition, not limited to the present embodiment, in the case of a structure in which a gas discharge valve is provided on the other side in the Z direction, i.e., the bottom of the outer tank 35, and the internal gas is discharged from the other side in the Z direction when the internal pressure rises, the collector lead 69 may be connected to the outer tank 35 by crossing the edge of the opening of the second retaining frame 55 and the edge of the bottom of the outer tank 35 exposed from the opening as the negative terminal.

[0058] Summary

[0059] The battery pack 10 of the present embodiment comprises: a battery 30, which is provided with a cover 45, which is the top surface of a sealing body 36, as an external terminal, on one side in the Z direction, and discharges internal gas from one side in the Z direction when the internal pressure rises; a first holder 50, which holds a plurality of batteries 30 arranged in an array on one side in the Z direction and has an opening 52 for exposing the cover 45; and a collector plate 60, which abuts against a surface on one side of the first holder 50 at an abutting portion 61 and is connected to the cover 45 exposed from the opening 52, the collector plate 60 protruding from the abutting portion 61 to one side in the length direction, blocking a part of the opening 52 and being connected to the cover 45, and a top plate portion 63 of an edge portion of the collector plate 60 blocking the opening 52 protruding to a position closer to one side than a surface on one side in the length direction of the first holder 50, thereby forming a space between the abutting portion 61, the top plate portion 63 of the edge portion of the collector plate 60 blocking the opening 52, and the cover 45.

[0060] By adopting the above structure, when the battery 30 thermally runs away, the internal gas discharged from the battery 30 will not be blocked by the collector plate 60, and can be easily discharged to the outside of the first holder 50. As a result, it is possible to avoid a situation where, when one battery 30 of the battery module 20 thermally runs away, the high-temperature internal gas flows into the inside of the first holder 50, and the high-temperature internal gas contacts other batteries 30 inside the first holder 50, causing other batteries 30 inside the first holder 50 to thermally run away, thereby preventing a chain reaction of thermal runaway.

[0061] <Other embodiments>

[0062] use Figure 6 to Figure 8 The current collector plates 70 , 80 , and 90 will be described as another example of the embodiment.

[0063] like Figure 6As shown, the collector plate 70 has a contact portion 71, a rising portion 72, a top plate portion 73, an inclined portion 74, and a joint portion 75, which are described in detail later, from the surface of one side in the Z direction of the first holder 50 to the cover 45 as the positive terminal. The top plate portion 73, the inclined portion 74, and the joint portion 75 are the same as the top plate portion 63, the inclined portion 64, and the joint portion 65 of the collector plate 60 described above, and therefore the description thereof is omitted.

[0064] The contact portion 71 is a portion that contacts one surface of the first holder 50 in the Z direction. The contact portion 71 is preferably disposed in the center between the two openings 52. The contact portion 71 is about twice the thickness of the rising portion 72.

[0065] The rising portion 72 is a portion extending from both ends of the abutting portion 71 in the X direction toward one side in the Z direction. The rising portion 72A on one side abuts against the rising portion 72B on the other side without any space. Thus, the top plate portion 73A on one side and the top plate portion 73B on the other side are electrically connected, so that the potential resistance can be reduced compared with, for example, the above-mentioned collector plate 60.

[0066] With such a structure, a space is formed between the top plate 73 and the cover 45. Thus, the internal gas of the battery 30 exhausted from the opening 52 of the first holder 50 is easily discharged to the outside of the first holder 50 without contacting the battery 30 held inside the first holder 50.

[0067] like Figure 7 As shown, the current collector plate 80 has a bent portion 81, an inclined portion 84, and a joint portion 85, which will be described in detail later, from the surface on one side of the first holder 50 in the Z direction to the cap 45 as the positive terminal. The inclined portion 84 and the joint portion 85 are the same as the inclined portion 64 and the joint portion 65 of the current collector plate 60 described above, so the description thereof is omitted.

[0068] The curved portion 81 bulges toward the other side in the Z direction. The central portion of the curved portion 81 in the X direction abuts against the surface of one side in the Z direction of the first holder 50. One side and the other side in the X direction of the curved portion 81 are connected to the inclined portion 84 so as to straddle the edge of the opening 52 of the first holder 50 and the edge of the cover 45 exposed from the opening 52.

[0069] With such a structure, a space is formed between the bent portion 81 and the cover 45. Thus, the internal gas of the battery 30 exhausted from the opening 52 of the first holder 50 is easily discharged to the outside of the first holder 50 without contacting the battery 30 held inside the first holder 50.

[0070] like Figure 8As shown, the current collector plate 90 has a bent portion 91, a top plate portion 93, an inclined portion 94, and a joint portion 95, which are described in detail later, from the surface of one side in the Z direction of the first holder 50 to the cap 45 as the positive terminal. The top plate portion 93, the inclined portion 94, and the joint portion 95 are the same as the top plate portion 63, the inclined portion 64, and the joint portion 65 of the above-mentioned current collector plate 60, and therefore the description thereof is omitted.

[0071] The bent portion 91 is bent so as to protrude toward the other side in the Z direction. The center portion of the bent portion 91 in the X direction abuts against the surface of one side in the Z direction of the first holder 50. One side and the other side in the X direction of the bent portion 91 are connected to the inclined portion 94 so as to straddle the edge of the opening 52 of the first holder 50 and the edge of the cover 45 exposed from the opening 52.

[0072] With such a structure, a space is formed between the top plate 93 and the cover 45. Thus, the internal gas of the battery 30 exhausted from the opening 52 of the first holder 50 is easily discharged to the outside of the first holder 50 without contacting the battery 30 held inside the first holder 50.

[0073] In addition, the present invention is not limited to the above-described embodiment and its modified examples, and it goes without saying that various changes and improvements can be made within the scope of the matters described in the claims of the present application.

[0074] Description of Reference Numerals

[0075] 10. Battery pack; 11. Outer casing; 12. External terminal of battery pack; 13. Vent; 20. Battery module; 30. Battery; 31. Positive electrode; 32. Negative electrode; 33. Diaphragm; 34. Electrode body; 35. Outer can; 36. Sealing body; 37. Insulating plate; 38. Insulating plate; 39. Positive electrode lead; 40. Negative electrode lead; 41. Internal terminal plate; 42. Lower valve body; 43. Insulating member; 44. Upper valve body; 45. Cover (external terminal); 45A, Vent; 50. First retainer; 5 1. accommodating portion; 52. opening; 55. second retaining frame; 60. current collecting plate; 61. abutting portion; 62. rising portion; 63. top plate; 64. inclined portion; 65. joining portion; 69. current collecting lead; 70. current collecting plate; 71. abutting portion; 72. rising portion; 73. top plate; 74. inclined portion; 75. joining portion; 80. current collecting plate; 81. bending portion; 84. inclined portion; 85. joining portion; 90. current collecting plate; 91. bending portion; 93. top plate; 94. inclined portion; 95. joining portion.

Claims

1. A battery pack, wherein: The battery pack has: A battery having an external terminal on one side in the length direction, the battery discharging internal gas from the one side in the length direction when the internal pressure of the battery increases; A holder that holds one side of the length direction of the plurality of batteries arranged in an array and has an opening for exposing the external terminal; as well as a current collector plate having a contact portion that contacts one surface of the retainer, the current collector plate closing a portion of the opening and connected to the external terminal, The collector plate protrudes from the abutment to one side in the length direction, blocks a portion of the opening and is connected to the external terminal. The portion of the collector plate that blocks the opening protrudes to a position closer to one side than a surface on one side in the length direction of the retaining frame, thereby forming a space between the abutment, the portion of the collector plate that blocks the opening and the external terminal.

2. The battery pack according to claim 1, wherein: The holder holds the two batteries. The collector plate connects the positive terminals of the two batteries to each other and comprises: a top plate portion on one side, which blocks a portion of the opening on one side; a rising portion on one side, which extends from a surface of one side of the holder toward one side in the length direction and is connected to the top plate portion on one side; a top plate portion on the other side, which blocks a portion of the opening on the other side; and a rising portion on the other side, which extends from a surface of one side of the holder toward one side in the length direction and is connected to the top plate portion on the other side. The rising portion on one side abuts against the rising portion on the other side.

3. The battery pack according to claim 1, wherein: The holder holds the two batteries. The current collector plate further includes a bent portion that bulges toward the other side in the longitudinal direction, and the abutment portion is formed at a central portion in the arrangement direction of the batteries.

4. The battery pack according to claim 1, wherein: The holder holds the two batteries. The current collector plate further includes a bent portion that is bent so as to protrude toward the other side in the longitudinal direction, and the abutment portion is formed at a central portion in the arrangement direction of the batteries.

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