Battery

Abstract

To achieve an increase in battery capacity.SOLUTION: A battery 1 includes: an electrode body 10 that has a first surface with a positive electrode terminal 11 and a negative electrode terminal 12 located thereon; and an exterior member 20 that houses the electrode body 10. The exterior member 20 includes: a box member 30 which has a box shape including a flat plate-shaped first side part 31 that faces the first surface and has a through hole 31a, a flat plate-shaped second side part 32 that is located on the side opposite to the first side part 31, and a flat plate-shaped third side part 33 that connects the first side part 31 and the second side part 32, the box member being electrically connected to the negative electrode terminal 12; a plate member 40 disposed inside the through hole 31a to be separated from the first side part 31 in plan view from the first side part 31 and electrically connected to the positive electrode terminal 11; and a sealing body 50 overlapping the first side part 31, the plate member 40, and a gap G between the first side part 31 and the plate member 40 in plan view from the first side part 31, the sealing body sealing the gap G.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] Patent Document 1 discloses, as an example of a battery, a prismatic battery including a battery case with an opening, a sealing plate that seals the opening, and an electrode plate assembly housed in the battery case. The positive electrode lead of the electrode plate assembly is electrically connected to the sealing plate. The negative electrode lead of the electrode plate assembly is electrically connected via an internal terminal to an external terminal that penetrates the sealing plate while being electrically insulated from the sealing plate. The prismatic battery of Patent Document 1 also includes a gasket and an insulator frame that electrically insulate the external and internal terminals from the sealing plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-242957 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery of Patent Document 1, the internal terminals and insulator frame are arranged inside the battery case that houses the electrode plate assembly (electrode assembly). In this case, the volume of the electrode assembly is small relative to the volume of the battery case, resulting in a small battery capacity. However, there is a demand for an increased battery capacity.

[0005] The present disclosure has been made in view of the above, and aims to increase the capacity of a battery. [Means for solving the problem]

[0006] The battery of the present disclosure comprises an electrode body having a first surface on which a positive terminal and a negative terminal are located, and an exterior member that houses the electrode body, wherein the exterior member is box-shaped and has a flat first side that faces the first surface and has a through hole, a flat second side that is located on the opposite side of the electrode body from the first side, and a flat third side that connects the first side and the second side, and comprises: a box member that is electrically connected to the negative terminal; a plate member that is arranged inside the through hole and spaced apart from the first side in a plan view from the first side, and is electrically connected to the positive terminal; and a sealing body that overlaps the first side, the plate member, and a gap between the first side and the plate member in a plan view from the first side, and seals the gap. [Effects of the Invention]

[0007] According to the battery of the present disclosure, the capacity of the battery can be increased. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an exploded perspective view of the battery shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view of the battery shown in FIG. [Figure 4] FIG. 4 is a plan view of the battery as seen from the first side portion side. [Figure 5] FIG. 5 is a partially enlarged cross-sectional view of the sealing body shown in FIG. [Figure 6] FIG. 6 is an exploded perspective view of a battery according to a modified example of the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the drawings. Note that the present disclosure is not limited to these embodiments. Each embodiment is an example, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible.

[0010] Fig. 1 is a perspective view of a battery 1 according to an embodiment of the present disclosure. Fig. 2 is an exploded perspective view of the battery 1 shown in Fig. 1. Fig. 3 is a cross-sectional view of the battery 1 shown in Fig. 1.

[0011] The battery 1 is a secondary battery, such as a lithium battery. The battery 1 includes an electrode assembly 10 and an exterior member 20.

[0012] The electrode body 10 is a wound type electrode body. The electrode body 10 is formed by stacking long positive and negative electrodes with a separator interposed therebetween and winding them. The electrode body 10 is flat. Hereinafter, the thickness direction, width direction, and depth direction of the electrode body 10 are referred to as a first direction D1, a second direction D2, and a third direction D3. The electrode body 10 has a first end surface 10a (corresponding to a "first surface") and a second end surface 10b facing opposite each other in the third direction D3.

[0013] The first projected area of ​​the electrode body 10 along the first direction D1 is larger than the second projected area of ​​the electrode body 10 along the second direction D2. The second projected area is also larger than the third projected area of ​​the electrode body 10 along the third direction D3. The third projected area corresponds to the areas of the first end face 10a and the second end face 10b. In other words, the areas of the first end face 10a and the second end face 10b are smaller than the first projected area and the second projected area.

[0014] The electrode assembly 10 includes a strip-shaped positive electrode terminal 11 that is electrically connected to the positive electrode, and a strip-shaped negative electrode terminal 12 that is electrically connected to the negative electrode. The positive electrode terminal 11 and the negative electrode terminal 12 are located on a first end surface 10a of the electrode assembly 10.

[0015] The exterior member 20 houses the electrode assembly 10. The exterior member 20 includes a box member 30, a plate member 40, and a sealing body 50.

[0016] The box member 30 is box-shaped with the electrode body 10 located inside. The box member 30 is electrically conductive. The material of the box member 30 is, for example, Fe (iron), Cu (copper), Ni (nickel), stainless steel, iron alloy, copper alloy, nickel alloy, etc. The type of stainless steel is not particularly limited, but specific examples include SUS304 and SUS316.

[0017] The box member 30 has a first side portion 31, a second side portion 32, a third side portion 33, a pair of fourth side portions 34, and a fifth side portion 35.

[0018] The first side portion 31 is a flat plate that faces the first end surface 10a of the electrode body 10 and has a through hole 31a. The second side portion 32 is a flat plate that is located on the opposite side of the electrode body 10 from the first side portion 31. The second side portion 32 faces the second end surface 10b. The first side portion 31 and the second side portion 32 face each other in the third direction D3, with the electrode body 10 in between.

[0019] The third side portion 33 is a flat plate that connects the first side portion 31 and the second side portion 32. The third side portion 33 faces the electrode body 10 in the first direction D1. The pair of fourth side portions 34 are flat plate-shaped and face each other in the second direction D2, sandwiching the electrode body 10 therebetween. The pair of fourth side portions 34 are connected by the first side portion 31, the second side portion 32, and the third side portion 33 in the second direction D2. The fifth side portion 35 is a flat plate that is located on the opposite side of the electrode body 10 from the third side portion 33. The third side portion 33 and the fifth side portion 35 face each other in the first direction D1, sandwiching the electrode body 10 therebetween.

[0020] The first side portion 31, the second side portion 32, the third side portion 33, and the pair of fourth side portions 34 are integral and form a storage portion 30a that is open on one side in the first direction D1. In the storage portion 30a, the third side portion 33 corresponds to a bottom plate, and the first side portion 31, the second side portion 32, and the pair of fourth side portions 34 correspond to side plates. Furthermore, a flange portion F is arranged around the entire periphery of the opening of the storage portion 30a.

[0021] The fifth side portion 35 constitutes the lid portion 30b that covers the opening of the storage portion 30a. The peripheral edge portion of the lid portion 30b is joined to the flange portion F by, for example, laser welding along the entire periphery. This electrically connects the storage portion 30a and the lid portion 30b and also seals the gap between the storage portion 30a and the lid portion 30b.

[0022] The negative electrode terminal 12 is joined to the inner surface of the housing portion 30a (for example, the inner surface of the fourth side portion 34) by, for example, resistance welding. This electrically connects the housing portion 30a to the negative electrode terminal 12. In other words, the box member 30 is electrically connected to the negative electrode terminal 12.

[0023] FIG. 4 is a plan view of the battery 1 as seen from the first side portion 31 side.

[0024] The plate member 40 shown in FIGS. 1, 2, 3, and 4 is flat and electrically conductive. The thickness of the plate member 40 is approximately equal to the thickness of the first side portion 31. The plate member 40 is made of aluminum, an aluminum alloy, or the like. Alternatively, the plate member 40 may be made of a clad material formed by roll-bonding an aluminum layer with a metal layer made of one or more of iron (Fe), copper (Cu), nickel (Ni), stainless steel, an iron alloy, a copper alloy, and a nickel alloy. Furthermore, the plate member 40 may be a composite member having a three-layer structure of an aluminum (Al) layer, a stainless steel layer, and a nickel layer. The type of stainless steel is not particularly limited, but examples include SUS304 and SUS316.

[0025] In a plan view seen from the first side portion 31 side, the plate member 40 is arranged inside the through hole 31a at a distance from the first side portion 31. The plate member 40 faces the first end surface 10a of the electrode body 10. In a plan view seen from the first side portion 31 side, there is a gap G between the first side portion 31 and the plate member 40 around the entire periphery of the plate member 40. The gap G electrically insulates the plate member 40 from the box member 30.

[0026] 3, the positive electrode terminal 11 is joined to the inner surface of the plate member 40 by, for example, laser welding. In this way, the plate member 40 is electrically connected to the positive electrode terminal 11.

[0027] The battery 1 also includes a first insulator 60 and a second insulator 70. The first insulator 60 is strip-shaped and is disposed on the positive electrode terminal 11. The first insulator 60 electrically insulates the positive electrode terminal 11 from the exterior member 20. The second insulator 70 is disposed on the first end surface 10a of the electrode assembly 10. The second insulator 70 electrically insulates the positive electrode terminal 11 from the negative electrode.

[0028] The sealing body 50 seals the gap G between the first side portion 31 and the plate member 40. The sealing body 50 is annular in plan view. In plan view seen from the first side portion 31 side, the sealing body 50 overlaps with the first side portion 31, the plate member 40, and the gap G. The sealing body 50 is disposed on the outer surface of the first side portion 31. The plate member 40 is exposed from the inside of the sealing body 50.

[0029] Fig. 5 is a partially enlarged cross-sectional view of the sealing body 50 shown in Fig. 3. The sealing body 50 includes a base layer 51, a bonding layer 52, and a protective layer 53.

[0030] The material of the base layer 51 is, for example, stainless steel. The type of stainless steel is not particularly limited, but specific examples include SUS304 and SUS316. The material of the base layer 51 may also be, for example, an elemental metal such as aluminum, iron, copper, or nickel, or an alloy thereof, such as an aluminum alloy, an iron alloy, a copper alloy, or a nickel alloy.

[0031] The bonding layer 52 overlaps the base material layer 51 and bonds the first side portion 31 and the plate member 40 to the base material layer 51. The bonding layer 52 has electrical insulation properties. The material of the bonding layer 52 is a thermoplastic resin. Examples of the material of the bonding layer 52 include polypropylene (PP) and polyethylene (PE). The material of the bonding layer 52 may also be unstretched polypropylene (CPP) and polyphenylene sulfide (PPS).

[0032] The protective layer 53 overlaps the base material layer 51 on the side opposite to the bonding layer 52, and protects the base material layer 51. The protective layer 53 has electrical insulation properties. The heat resistance of the protective layer 53 is higher than that of the bonding layer 52. The material of the protective layer 53 is a thermoplastic resin. Examples of the material of the protective layer 53 include nylon and polyethylene terephthalate (PET).

[0033] The sealing body 50 is joined to the first side portion 31 and the plate member 40 by thermal welding. The joining strength between the sealing body 50 and the first side portion 31 and the plate member 40 is smaller than the joining strength between the storage portion 30a and the lid portion 30b of the box member 30.

[0034] Furthermore, when the internal pressure of the exterior member 20 is equal to or greater than a predetermined pressure, the seal 50 ruptures. That is, the seal 50 functions as a rupture valve. The predetermined pressure is a pressure that ensures the safety of the battery 1.

[0035] For example, if the positive electrode and negative electrode in the electrode body 10 are short-circuited, gas is generated from the electrode body 10 and the electrode body 10 generates abnormal heat. This softens the bonding layer 52, and when the internal pressure of the exterior member 20 exceeds a predetermined pressure, the bonding layer 52 ruptures and the gas leaks from the gap G. This suppresses an increase in the internal pressure of the exterior member 20, ensuring the safety of the battery 1.

[0036] The materials and thicknesses of the base layer 51, the bonding layer 52, and the protective layer 53 are determined so that the sealing body 50 will rupture when the internal pressure of the exterior member 20 reaches a predetermined pressure or higher.

[0037] As described above, inside the box member 30, the third side portion 33 and the fifth side portion 35 face each other in the first direction D1 with the electrode body 10 in between, the pair of fourth side portions 34 face each other in the second direction D2 with the electrode body 10 in between, and the first side portion 31 and the second side portion 32 face each other in the third direction D3 with the electrode body 10 in between. In addition, by arranging both the positive electrode terminal 11 and the negative electrode terminal 12 on the first end surface 10a, the first side portion 31 faces the first end surface 10a of the electrode body 10 on which the positive electrode terminal 11 and the negative electrode terminal 12 are located.

[0038] When both the positive electrode terminal 11 and the negative electrode terminal 12 are arranged on the first end surface 10a, the gap between the second side portion 32 and the electrode body 10 can be made smaller than when, for example, the positive electrode terminal 11 is arranged on the first end surface 10a and the negative electrode terminal 12 is arranged on the second end surface 10b. Similarly, when both the positive electrode terminal 11 and the negative electrode terminal 12 are arranged on the first end surface 10a, the gap between the third side portion 33, the pair of fourth side portions 34, and the fifth side portion 35 and the electrode body 10 can be made smaller. Therefore, the volume of the electrode body 10 can be made larger relative to the volume of the exterior member 20.

[0039] Furthermore, the plate member 40 is flat and has a thickness substantially equal to that of the first side portion 31, and is positioned inside the through-hole 31a of the first side portion 31. In other words, the plate member 40 is prevented from being positioned inside the box member 30. Furthermore, the sealing body 50 is disposed on the outer surface of the first side portion 31. This allows the thickness in the third direction D3 of the member disposed on the first side portion 31 to be reduced. This allows the gap between the first side portion 31 and the electrode body 10 to be reduced. This therefore allows the volume of the electrode body 10 to be increased relative to the volume of the exterior member 20. In other words, the capacity of the battery 1 can be increased.

[0040] Furthermore, as described above, in the electrode body 10, the area of ​​the first end face 10a, which corresponds to the projected area in the third direction, is smaller than the first projected area in the first direction D1 and the second projected area in the second direction D2. Therefore, when the positive electrode terminal 11 and the negative electrode terminal 12 are located on the first end face 10a, the gap between the electrode body 10 and the box member 30 can be made smaller than when the positive electrode terminal 11 and the negative electrode terminal 12 are located in a portion of the electrode body 10 facing the third side portion 33 or the fourth side portion 34. This allows the capacity of the battery 1 to be further increased.

[0041] Furthermore, as described above, the seal 50 functions as a split valve. This means that the battery 1 does not need to be provided with a separate split valve. This allows the battery 1 to have a reduced number of parts, fewer manufacturing steps, and lower costs.

[0042] The above-described embodiments are intended to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. The present disclosure may be modified or improved without departing from the spirit thereof, and equivalents thereof are also included in the present disclosure.

[0043] For example, the electrode assembly 10 may be a rectangular parallelepiped laminate in which a plurality of sheet-shaped positive electrodes and a plurality of sheet-shaped negative electrodes are alternately stacked with separators interposed therebetween.

[0044] Furthermore, the housing portion 30a may not have the flange portion F. In this case, the peripheral edge of the lid portion 30b is joined to the peripheral edge of the opening of the housing portion 30a.

[0045] FIG. 6 is an exploded perspective view of a battery 1 according to a modified embodiment of the present disclosure. The battery 1 of this modified embodiment differs from the battery 1 of the above-described embodiment in the configuration of the box member 130. In the box member 130 of this modified embodiment, the second side portion 132, the third side portion 133, the pair of fourth side portions 134, and the fifth side portion 135 are integral and form a housing portion 130a that opens on one side in the third direction D3. The first side portion 131 also forms a lid portion 130b that covers the opening of the housing portion 130a. The peripheral portion of the lid portion 130b is joined to the periphery of the opening of the housing portion 130a along the entire periphery. In this modified embodiment, the cross-sectional shape of the pair of fourth side portions 134 may be arc-shaped.

[0046] The present disclosure may also be implemented as a combination of the following configurations.

[0047] (1) an electrode body having a first surface on which a positive electrode terminal and a negative electrode terminal are located; an exterior member that houses the electrode body, The exterior member is a box-shaped box member having a flat plate-like first side portion facing the first surface and having a through hole, a flat plate-like second side portion positioned on the opposite side of the electrode body from the first side portion, and a flat plate-like third side portion connecting the first side portion and the second side portion, the box member being electrically connected to the negative electrode terminal; a plate member that is disposed inside the through hole and spaced apart from the first side portion in a plan view seen from the first side portion, and that is electrically connected to the positive electrode terminal; In a plan view seen from the first side portion side, the first side portion, the plate member, and a sealing body that overlaps with a gap between the first side portion and the plate member and seals the gap, battery.

[0048] (2) The sealing body is a substrate layer; a bonding layer that overlaps the base layer and bonds the first side portion and the plate member to the base layer, (1) The battery according to (1).

[0049] (3) The material of the bonding layer is a thermoplastic resin. (2) The battery according to (1).

[0050] (4) The seal is disposed on an outer surface of the first side portion. A battery according to any one of (1) to (3).

[0051] (5) When the internal pressure of the exterior member is equal to or greater than a predetermined pressure, the sealing body ruptures. A battery according to any one of (1) to (4). [Explanation of symbols]

[0052] 1 battery 10 Electrode body 10a 1st end surface (1st surface) 10b 2nd end face 11 Positive terminal 12 Negative terminal 20 Exterior materials 30 Box material 31 First side 31a Through hole 32 Second side 33 Third Side 34 Fourth Side 35 5th side 40 Plate members 50 Sealing body 51 Base material layer 52 Bonding layer 53 Protective layer G Gap

Claims

1. an electrode body having a first surface on which a positive electrode terminal and a negative electrode terminal are located; an exterior member that houses the electrode body, The exterior member is a box member having a flat plate-like first side portion facing the first surface and having a through hole, a flat plate-like second side portion positioned on the opposite side of the electrode body from the first side portion, and a flat plate-like third side portion connecting the first side portion and the second side portion, the box member being electrically connected to the negative electrode terminal; a plate member that is disposed inside the through hole and spaced apart from the first side portion in a plan view seen from the first side portion, and that is electrically connected to the positive electrode terminal; In a plan view seen from the first side portion, the first side portion, the plate member, and a sealing body that overlaps with a gap between the first side portion and the plate member and seals the gap, battery.

2. The sealing body is a substrate layer; a bonding layer that overlaps the base layer and bonds the first side portion and the plate member to the base layer, The battery of claim 1 .

3. The material of the bonding layer is a thermoplastic resin. The battery of claim 2.

4. The seal is disposed on an outer surface of the first side. The battery of claim 1 .

5. When the internal pressure of the exterior member is equal to or greater than a predetermined pressure, the sealing body ruptures. The battery of claim 1 .

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