Battery holder

Abstract

A battery holder (50), which is an example of an embodiment, includes a plurality of housing parts (51) that respectively accommodate a plurality of cylindrical batteries (10) such that the outer peripheries of the cylindrical batteries (10) in the longitudinal direction are held in a state in which the positive electrode sides and the negative electrode sides thereof are aligned. Each cylindrical battery (10) includes: an electrode body (14); a bottomed cylindrical exterior can (16) that accommodates the electrode body (14); and a positive electrode cap (27) that seals the opening of the exterior can (16). The positive electrode cap (27) has a slit (64). Each housing part (51) has a locking part (52) that engages with the slit (64) to fix and hold the cylindrical battery (10) at a prescribed position.

Description

Battery Holder

[0001] The present disclosure relates to a battery holder.

[0002] Generally, lithium-ion batteries are used in the form of battery packs in which a plurality of batteries are housed in a battery holder and electrically connected by a current collector plate. In the case of cylindrical batteries, the batteries may rotate within the battery holder, causing the current collector plate that was electrically connected to the batteries to come loose and resulting in a connection failure between the batteries and the current collector plate.

[0003] Patent Document 1 describes that by providing a fixing plate having an engaging portion that engages with grooves formed on the side surface or positive electrode terminal of a battery within a battery pack, the rotation of a cylindrical battery can be suppressed.

[0004] International Publication No. 2012-147134

[0005] However, when introducing the fixing plate of Patent Document 1, a space for arranging engaging portions for suppressing the movement of the battery around and above the battery is required, resulting in a loss in the volume energy density of the battery pack.

[0006] A battery holder according to one aspect of the present disclosure includes a plurality of storage portions that hold and respectively house the outer circumferences in the longitudinal direction of cylindrical batteries with the positive electrode sides and negative electrode sides of the plurality of cylindrical batteries aligned. The cylindrical battery includes an electrode body, a bottomed cylindrical outer can that houses the electrode body, and a positive electrode cap that seals the opening of the outer can. The positive electrode cap has a slit, and the storage portion has a locking portion that engages with the slit to fixedly hold the cylindrical battery at a specified position.

[0007] According to the battery holder according to the present disclosure, it is possible to suppress the rotation of the batteries within the battery holder without degrading the volume energy density of the battery pack, and to achieve a stable connection between the batteries and the current collector plate.

[0008] This is an axial cross-sectional view of a cylindrical battery, which is an example of an embodiment. This is an exploded perspective view of a battery holder and a cylindrical battery, which is an example of an embodiment. This is an enlarged cross-sectional view of the positive electrode portion of a cylindrical battery housed in a battery holder, which is an example of an embodiment. This is a plan view of a battery holder and a cylindrical battery, which is another example of an embodiment, viewed from the axial top surface. This is an enlarged perspective view of the positive electrode side of a battery holder and a cylindrical battery, which is an example of an embodiment.

[0009] Hereinafter, an example of an embodiment of the cylindrical battery according to this disclosure will be described in detail with reference to the drawings. The embodiment described below is merely an example, and this disclosure is not limited to the embodiments described below. Furthermore, forms obtained by selectively combining each component of the embodiments described below are included in this disclosure.

[0010] Figure 1 is a schematic diagram showing an axial cross-section of a cylindrical battery 10, which is an example of an embodiment. As shown in Figure 1, the cylindrical battery 10 comprises an electrode body 14 having a wound structure, an electrolyte, and a bottomed cylindrical outer casing 16 that houses the electrode body 14 and the electrolyte. The electrode body 14 has a positive electrode 11, a negative electrode 12, and a separator 13, and has a structure in which the positive electrode 11 and the negative electrode 12 are wound in a spiral shape via the separator 13. The outer casing 16 is a bottomed cylindrical metal container with one side open in the axial direction, and the opening of the outer casing 16 is sealed by a sealing body 17. In the following, for convenience of explanation, the side of the cylindrical battery 10 with the sealing body 17 will be referred to as the top, and the bottom side of the outer casing 16 as the bottom.

[0011] The electrolyte may be an aqueous electrolyte, but in this embodiment, a non-aqueous electrolyte is used. The non-aqueous electrolyte has lithium-ion conductivity. The non-aqueous electrolyte may be a liquid electrolyte (electrolyte solution) or a solid electrolyte. The cylindrical battery 10 is, for example, a non-aqueous electrolyte secondary battery, and among these, a lithium-ion battery is preferred.

[0012] A liquid electrolyte (electrolyte solution) comprises a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. Examples of non-aqueous solvents include esters, ethers, nitriles, amides, and mixtures of two or more of these. Examples of non-aqueous solvents include ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and mixtures thereof. The non-aqueous solvent may also contain halogen-substituted solvents (e.g., fluoroethylene carbonate) in which at least some of the hydrogen atoms in the solvent are replaced with halogen atoms such as fluorine. Examples of electrolyte salts include LiPF4. ６ Lithium salts such as these are used.

[0013] As the solid electrolyte, for example, a solid or gel-like polymer electrolyte, an inorganic solid electrolyte, etc., can be used. As the inorganic solid electrolyte, materials known for all-solid-state lithium-ion secondary batteries, etc. (for example, oxide-based solid electrolytes, sulfide-based solid electrolytes, halogen-based solid electrolytes, etc.) can be used. The polymer electrolyte includes, for example, a lithium salt and a matrix polymer, or a non-aqueous solvent, a lithium salt and a matrix polymer. As the matrix polymer, for example, a polymer material that absorbs a non-aqueous solvent and gels is used. Examples of polymer materials include fluororesins, acrylic resins, polyether resins, etc.

[0014] The positive electrode 11, negative electrode 12, and separator 13 constituting the electrode body 14 are all elongated strips that are wound in a spiral shape and alternately stacked in the radial direction of the electrode body 14. The negative electrode 12 is formed to be slightly larger than the positive electrode 11 in order to prevent lithium deposition. That is, the negative electrode 12 is formed to be longer than the positive electrode 11 in both the length and width (short side) directions. The separator 13 is formed to be at least slightly larger than the positive electrode 11, and two separators are arranged so as to sandwich the positive electrode 11. The cylindrical battery 10 includes insulating plates 18 and 19 arranged above and below the electrode body 14, respectively.

[0015] The electrode body 14 has a positive electrode lead 20 connected to the positive electrode 11 by welding or the like, and a negative electrode lead 21 connected to the negative electrode 12 by welding or the like. In this embodiment, the positive electrode lead 20 is connected to the longitudinal center of the positive electrode 11, and the negative electrode lead 21 is connected to the longitudinal end of the negative electrode 12 located on the winding core side of the electrode body 14.

[0016] The positive electrode 11 comprises a positive electrode core 30 and a positive electrode mixture layer 31 formed on the positive electrode core 30. The positive electrode core 30 can be made of a metal foil that is stable within the potential range of the positive electrode 11, such as aluminum or an aluminum alloy, or a film with the metal arranged on its surface. The positive electrode mixture layer 31 contains a positive electrode active material, a conductive agent, and a binder, and is preferably formed on both sides of the positive electrode core 30, excluding the portion where the positive electrode lead 20 is welded. The positive electrode 11 can be manufactured, for example, by applying a positive electrode mixture slurry containing a positive electrode active material, a conductive agent, and a binder onto the positive electrode core 30, drying the coating, and then compressing it to form the positive electrode mixture layer 31 on both sides of the positive electrode core 30.

[0017] The positive electrode composite layer 31 generally contains particulate lithium metal composite oxide as the positive electrode active material. The lithium metal composite oxide is a composite oxide containing metal elements such as Co, Mn, Ni, and Al in addition to Li. The metal elements constituting the lithium metal composite oxide are, for example, at least one selected from Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Sn, Sb, W, Pb, and Bi. Among these, it is preferable to contain at least one selected from Co, Ni, and Mn. Examples of suitable composite oxides include lithium metal composite oxides containing Ni, Co, and Mn, and lithium metal composite oxides containing Ni, Co, and Al.

[0018] The negative electrode 12 comprises a negative electrode core 40 and a negative electrode mixture layer 41 formed on the negative electrode core 40. The negative electrode core 40 can be made of a metal foil that is stable in the potential range of the negative electrode 12, such as copper or a copper alloy, or a film with the metal arranged on its surface. The negative electrode mixture layer 41 contains a negative electrode active material, a binder, and optionally a conductive agent, and is preferably formed on both sides of the negative electrode core 40, excluding the exposed portion 42 and the portion to which the negative electrode lead 21 is welded. The negative electrode 12 can be manufactured by applying a negative electrode mixture slurry containing a negative electrode active material and a binder to the surface of the negative electrode core 40, drying the coating, and then compressing it to form the negative electrode mixture layer 41 on both sides of the negative electrode core 40.

[0019] The negative electrode composite layer 41 generally contains a carbon material that reversibly intercepts and releases lithium ions as the negative electrode active material. A preferred example of the carbon material is graphite, such as natural graphite or artificial graphite. Alternatively, a material containing at least one of an element that alloys with Li, such as Si or Sn, and a material containing such an element may be used as the negative electrode active material. Among these, a composite material containing Si is preferred. A preferred Si-containing composite material is a composite particle containing an ion-conducting phase and a Si phase dispersed in the ion-conducting phase. A carbon material and a Si-containing composite material may be used in combination as the negative electrode active material, which is preferable from the viewpoint of achieving both high capacity and high durability of the battery.

[0020] A porous sheet having ion permeability and insulating properties is used for the separator 13. Specific examples of porous sheets include microporous thin films, woven fabrics, and nonwoven fabrics. Suitable materials for the separator 13 include polyethylene, polyolefins such as polypropylene, and cellulose. The separator 13 may have a single-layer structure or a multi-layer structure. A heat-resistant resin layer, such as aramid resin, may be formed on the surface of the separator 13. A filler layer containing an inorganic filler may be formed at the interface between the separator 13 and at least one of the positive electrode 11 and the negative electrode 12.

[0021] A negative electrode 12 is positioned on the outer circumferential surface of the electrode body 14, and an exposed portion 42 is formed where the surface of the negative electrode core 40 is exposed. The exposed portion 42 may be formed on a part of the outer circumferential surface of the electrode body 14, but preferably it is formed over the entire outer circumferential surface. The exposed portion 42 may be formed only on one side (outer surface) of the negative electrode core 40 facing outward from the electrode body 14, or it may be formed on both sides of the negative electrode core 40. For example, the exposed portion 42 is formed in a range of about one to two turns of the circumference of the electrode body 14 from the longitudinal end of the negative electrode 12 located on the outer circumferential surface of the electrode body 14.

[0022] In the cylindrical battery 10, the outer casing 16 houses the electrode body 14. Specifically, the exposed portion 42 of the negative electrode 12 contacts the inner surface of the outer casing 16, and the negative electrode lead 21 is connected to the inner surface of the bottom of the outer casing 16 by welding or the like. The exposed portion 42, for example, contacts the inner surface of the outer casing 16 around the entire circumference of the outer surface of the electrode body 14. The positive electrode lead 20 extends towards the sealing body 17 through a through hole in the insulating plate 18 and is connected to the lower surface of the internal terminal plate 23, which is the bottom plate of the sealing body 17, by welding or the like. Therefore, in this embodiment, the sealing body 17 becomes the positive electrode external terminal, and the outer casing 16 becomes the negative electrode external terminal.

[0023] As described above, the outer casing 16 is a bottomed cylindrical metal container with one side open in the axial direction. A gasket 28 is provided between the outer casing 16 and the sealing body 17 to ensure airtightness inside the battery and insulation between the outer casing 16 and the sealing body 17. The outer casing 16 has a grooved portion 22 formed on its side surface, which protrudes inward to support the sealing body 17. The grooved portion 22 is preferably formed in an annular shape along the circumferential direction of the outer casing 16, and its upper surface supports the sealing body 17. The sealing body 17 is fixed to the upper part of the outer casing 16 by the grooved portion 22 and the opening edge portion 29 of the outer casing 16 which is crimped to the sealing body 17.

[0024] The sealing body 17 has a structure in which an internal terminal plate 23, a lower valve body 24, an insulating member 25, an upper valve body 26, and a positive electrode cap 27 are stacked in order from the electrode body 14 side. Each component constituting the sealing body 17 has, for example, a disc shape or a ring shape, and each component except the insulating member 25 is electrically connected to one another. The lower valve body 24 and the upper valve body 26 are connected at their respective centers, and the insulating member 25 is interposed between their respective peripheral edges.

[0025] The positive electrode cap 27 is positioned on the outermost part of the sealing body 17 and forms the top surface of the cylindrical battery 10. The positive electrode cap 27 is made of a disc-shaped metal plate and has dimensions that allow it to seal the opening of the outer casing 16. The composition of the metal plate is not particularly limited, but is generally made of iron or an iron alloy (e.g., stainless steel). An example of the thickness of the metal plate is 0.1 mm to 0.8 mm. The positive electrode cap 27 is manufactured, for example, by deep drawing a metal plate. As will be described in more detail later, the positive electrode cap 27 has a plurality of slits 64. When an abnormality occurs in the battery and the internal pressure rises, the lower valve body 24 deforms and breaks, pushing the upper valve body 26 towards the positive electrode cap 27, thereby interrupting the current path between the lower valve body 24 and the upper valve body 26. If the internal pressure rises further, the upper valve body 26 breaks, and gas is discharged from the slits 64 of the positive electrode cap 27.

[0026] Next, the battery holder 50 will be described in detail using Figures 2 to 5. Figure 2 is an exploded perspective view of a battery holder and cylindrical battery, which is an example of an embodiment. Figure 3 is an enlarged cross-sectional view of the positive electrode portion of the battery holder and cylindrical battery housed in the battery holder, which is an example of an embodiment. Figure 4 is a plan view of the battery holder and cylindrical battery, which is another example of an embodiment, viewed from the axial top surface. Figure 5 is an enlarged perspective view of the positive electrode side of the battery holder and cylindrical battery, which is an example of an embodiment.

[0027] As shown in Figure 2, the battery holder 50 has a roughly rectangular parallelepiped shape, which is longer in the vertical and horizontal directions than in the vertical direction. The battery holder 50 has multiple storage sections 51 that hold and house the longitudinal outer circumference of the cylindrical batteries 10, with the positive and negative terminal sides of each cylindrical battery 10 aligned. The vertical length of the battery holder 50 is approximately the same as the axial length of the cylindrical batteries 10. The vertical length of the battery holder 50 is set according to the length of the row of cylindrical batteries 10, and the horizontal length is set according to the number of storage sections 51, etc.

[0028] The battery holder 50 is formed into a predetermined shape by extrusion molding or die casting, for example, using a curable resin as the material. The curable resin constituting the battery holder 50 is a resin having a cross-linked structure that does not melt even at high temperatures of 600°C or higher, and maintains the shape of the battery holder 50 by carbonizing without melting even at high temperatures of, for example, 800°C to 1000°C. Examples of curable resins include unsaturated polyester, epoxy resin, melamine resin, and phenolic resin.

[0029] The curable resin constituting the battery holder 50 contains, for example, at least one of a heat-absorbing filler and a heat-conducting filler, preferably both a heat-absorbing filler and a heat-conducting filler. The heat-absorbing filler exhibits an endothermic effect during thermal decomposition, and specific examples include aluminum hydroxide and sodium bicarbonate. Examples of heat-conducting fillers include metal oxides such as aluminum oxide and zinc oxide, metal nitrides such as aluminum nitride and boron nitride, and metal oxynitrides such as aluminum oxynitride.

[0030] The storage section 51 of the battery holder 50 has a locking portion 52 and an opening 53, described later, on the side where the positive electrode of the cylindrical battery 10 is stored. The storage section 51 has, for example, a cylindrical gap to hold the longitudinal outer circumference of the cylindrical battery 10. The storage section 51 has an insertion opening (not shown) for the cylindrical battery 10 on the side opposite to the locking portion 52 and the opening 53. The cylindrical battery 10 can be stored in the storage section 51 of the battery holder 50 by inserting the cylindrical battery 10 from the positive electrode side into the insertion opening of the storage section 51. After storing the cylindrical battery 10 in each storage section 51, a bottom plate (not shown) that closes the insertion opening is installed on the side where the insertion opening is provided, so that the cylindrical battery 10 is held in place without falling out of the storage section 51 of the battery holder 50.

[0031] As shown in Figure 3, the positive electrode cap 27 of the cylindrical battery 10 comprises a protrusion 60 formed in the center of a metal plate and a flange portion 61 formed around the protrusion 60. Since the flange portion 61 is pressed by the opening edge 29 of the outer casing 16, the positive electrode cap 27 needs to have a flange portion 61 of a certain width. On the other hand, since the protrusion 60 is the part to which lead wires (not shown) connected to an external device are connected by welding or the like, it is preferable that the protrusion 60 has a certain area considering the ease of connection and connection strength.

[0032] The protrusion 60 protrudes outward from the cylindrical battery 10. The height of the protrusion 60 is not particularly limited, but is for example 1 mm to 5 mm. The protrusion 60 has a top surface portion 62, a connecting portion 63 connected to the flange portion 61, and a slit 64 formed adjacent to the flange portion 61.

[0033] The storage portion 51 of the battery holder 50 has a locking portion 52 that engages with the slit 64 of the positive electrode cap 27 to fix and hold the cylindrical battery 10 in a defined position. Specifically, the locking portion 52, which is substantially the same as the arch shape of the slit 64 in plan view, engages with the gap in the slit 64, thereby suppressing radial rotation of the cylindrical battery 10 and allowing it to be fixed and held in place.

[0034] If the thickness of the locking portion 52 is such that at least the lower surface of the locking portion 52 is at the same height as the lower surface of the top surface 62 of the positive electrode cap 27, the locking portion 52 and the slit 64 will engage, and the rotation of the cylindrical battery 10 can be suppressed. If the lower surface of the locking portion 52 is within the height range of the slit 64 and is located below the lower surface of the top surface 62, the cylindrical battery 10 can be more firmly fixed and held. In order not to impair the volumetric energy density of the cylindrical battery 10, it is preferable to limit the upper limit of the thickness of the locking portion 52 to about 5 mm above the top surface 62.

[0035] The locking portion 52 may have a tapered shape (not shown) such that the surface 52a facing the top surface 62 of the positive electrode cap 27 tapers towards the axial center as it moves axially upward of the cylindrical battery 10. In this case, the cylindrical battery 10 can be fixed and held more firmly compared to the case where the surface 52a facing the top surface 62 of the locking portion 52 is perpendicular to the axial direction.

[0036] The shape of the locking portion 52 is not limited to being substantially the same as the arch shape of the slit 64 in plan view. For example, as shown in Figure 4, there may be two locking portions 52 that lock the left and right ends of the slit 64, but do not block the middle portion of the slit 64. In this case, since the middle portion of the slit 64 is not blocked, gas can be discharged from the slit 64 to which the locking portion 52 is engaged when a battery malfunction occurs. The locking portion 52 may also be shaped to lock onto both the left and right sides of the connecting portion 63.

[0037] The storage section 51 has an opening 53 for welding work at a position where the opening edge 29 of the outer casing 16 is exposed in an axial plan view of the cylindrical battery 10. When electrically connecting cylindrical batteries 10 to each other at the top of the battery holder 50, it is necessary to weld the opening edge 29 of the outer casing 16, which is the negative external terminal, to a lead wire (not shown) connected to an external device. However, it is extremely difficult to weld the external lead wire to the opening edge 29 of the outer casing 16 in the limited space at the top of the battery holder 50 while the cylindrical battery 10 can rotate within the storage section 51, and there is a possibility that the weld to the external lead wire may come undone due to the rotation of the cylindrical battery 10. Multiple cylindrical batteries 10 housed in the storage section 51 equipped with a locking part 52 are fixedly held by the locking part 52 and rotation is suppressed, so a better connection can be achieved when welding the opening edge 29 of the outer casing 16 exposed through the opening 53 to the external lead wire.

[0038] The size of the opening 53 is not particularly limited, but it is preferable that, in a plan view from the axial top surface of the cylindrical battery 10, the vertical dimension (circumferential length of the cylindrical battery 10) is 5 mm to 15 mm and the horizontal dimension (radial length of the cylindrical battery 10) is 3 mm to 10 mm.

[0039] The opening 53 may be installed at any location where the opening edge 29 of the outer casing 16 is exposed, but as shown in Figure 5, it is preferable to install it outside the locking portion 52 in the radial direction of the cylindrical battery 10. Outside the cylindrical battery 10 in the radial direction means the direction away from the central axis on a plane perpendicular to the central axis of the cylindrical battery 10. By providing the opening 53 closest to the locking portion 52 and outside the locking portion 52 in the radial direction of the cylindrical battery 10, the cylindrical battery 10 can be fixed in a specified position, minimizing rattling of the cylindrical battery 10, and achieving a better connection between the opening edge 29 of the outer casing 16 and the external lead. Furthermore, when the locking portion 52 engages with the slit 64, part or all of the slit 64 is blocked by the locking portion 52, but by providing the opening 53 outside the locking portion 52, gas generated during abnormal heat generation of the battery can be discharged from the opening 53 instead of the blocked portion of the slit 64.

[0040] The above embodiments can be modified as appropriate without impairing the purpose of this disclosure. For example, in the above embodiments, the vertical length of the battery holder 50 is approximately the same as the axial length of the cylindrical battery 10, and a bottom plate (not shown) is provided on the side with the insertion opening, but the form of the battery holder 50 is not limited thereto. For example, the battery holder 50 may be formed by connecting a first holder having a locking portion 52 and an opening 53, a vertical length that is half the axial length of the cylindrical battery 10, and a plurality of storage portions that hold the upper end of the cylindrical battery 10, and a second holder having a bottom, a vertical length that is half the axial length of the cylindrical battery 10, and a plurality of storage portions that hold the lower end of the cylindrical battery 10.

[0041] Alternatively, the battery holder 50 may be formed by connecting a first holder having a locking portion 52 and an opening 53, a vertical length being 1 / 3 of the axial length of the cylindrical battery 10, and a plurality of storage portions for holding the positive electrode end of the cylindrical battery 10; a second holder having a vertical length being 1 / 3 of the axial length of the cylindrical battery 10, a plurality of voids for holding the axial central portion of the cylindrical battery 10, and openings on the upper and lower sides; and a third holder having a bottom, a vertical length being 1 / 3 of the axial length of the cylindrical battery 10, and a plurality of storage portions for holding the negative electrode end of the cylindrical battery 10.

[0042] Furthermore, the battery holder of this disclosure may have the following configurations: Configuration 1: A battery holder comprising a plurality of storage compartments that hold and house the longitudinal outer circumference of a plurality of cylindrical batteries, with the positive electrode side and negative electrode side of each cylindrical battery aligned, wherein the cylindrical battery comprises an electrode body, a bottomed cylindrical outer casing that houses the electrode body, and a positive electrode cap that seals the opening of the outer casing, the positive electrode cap having a slit, and the storage compartment having a locking portion that engages with the slit to fix and hold the cylindrical battery in a defined position. Configuration 2: The battery holder according to Configuration 1, wherein each storage compartment has an opening for welding work to electrically connect the plurality of cylindrical batteries fixed and held by the locking portion, and the opening is provided such that the opening edge of the outer casing is exposed in an axial plan view of the cylindrical battery. Configuration 3: The battery holder according to Configuration 2, wherein the opening is located outside the locking portion in the radial direction of the cylindrical battery.

[0043] 10 Cylindrical battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 16 Case, 17 Sealing body, 18, 19 Insulating plate, 20 Positive electrode lead, 21 Negative electrode lead, 22 Grooved section, 23 Internal terminal plate, 24 Lower valve body, 25 Insulating member, 26 Upper valve body, 27 Positive electrode cap, 28 Gasket, 29 Opening edge, 30 Positive electrode core body, 31 Positive electrode mixture layer, 40 Negative electrode core body, 41 Negative electrode mixture layer, 42 Exposed section, 50 Battery holder, 51 Storage section, 52 Locking section, 53 Opening, 60 Protrusion, 61 Flange section, 62 Top surface section, 63 Connecting section, 64 Slit

Claims

1. A battery holder comprising a plurality of storage compartments for holding and housing the longitudinal outer circumference of a plurality of cylindrical batteries, with the positive and negative electrodes of each cylindrical battery aligned, wherein the cylindrical battery comprises an electrode body, a bottomed cylindrical outer casing for housing the electrode body, and a positive electrode cap for sealing the opening of the outer casing, the positive electrode cap having a slit, and the storage compartment having a locking portion that engages with the slit to fix and hold the cylindrical battery in a defined position.

2. The battery holder according to claim 1, wherein each storage section has an opening for welding work to electrically connect a plurality of cylindrical batteries that are fixedly held by the locking section, and the opening is provided such that the opening edge of the outer casing is exposed in an axial plan view of the cylindrical battery.

3. The battery holder according to claim 2, wherein the opening is located outside the locking portion in the radial direction of the cylindrical battery.

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