Battery cell

Abstract

To provide a battery cell preventing an insulating sheet covering an exterior can from interfering with surrounding members.SOLUTION: A battery cell includes: an electrode body; an exterior can that accommodates the electrode body and that has a prismatic shape with an outer surface; an electrode terminal provided on the outer surface of the exterior can; and a film-shaped insulating sheet provided on the outer surface of the exterior can. The outer surface of the exterior can includes: a first surface orthogonal to a first direction; and a second surface orthogonal to the first surface, and having a shape where the first direction is a longitudinal direction and a second direction orthogonal to the first direction is a lateral direction. The electrode terminal is provided on the second surface. The insulating sheet has a folded portion that reaches the second surface from the first surface of the exterior can. The folded portion includes a peak portion protruding from a first surface side to an electrode terminal side along the first direction, and valley portions located on both sides with respect to the peak portion in the second direction and recessed toward a side away from the electrode terminal. The insulating sheet is a shrink film shrunk by heat.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present technology relates to battery cells. [Background technology]

[0002] Battery cells equipped with an insulating film covering the outer surface of a rectangular outer can have been known for some time. Such insulating films and battery cells equipped with them are described, for example, in Japanese Patent Laid-Open No. 2014-63686 (Patent Document 1) and Japanese Patent Laid-Open No. 2016-154147 (Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-63686 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-154147 Summary of the Invention [Problem to be solved by the invention]

[0004] In the process of adhering the insulating film to the outer can, the insulating film may be deformed into an unintended shape. For example, if the deformed insulating film protrudes from the top surface of the outer can, there is a concern that it may interfere with other components that make up the battery module.

[0005] An object of the present technology is to provide a battery cell in which the insulating sheet covering the outer can is prevented from interfering with surrounding components. [Means for solving the problem]

[0006] The battery cell according to the present technology comprises an electrode body, a rectangular outer can that houses the electrode body and has an outer surface, an electrode terminal provided on the outer surface of the outer can, and a film-like insulating sheet provided on the outer surface of the outer can, wherein the outer surface of the outer can includes a first surface that is perpendicular to a first direction and a second surface that is perpendicular to the first surface and has a shape in which the first direction is its longitudinal direction and a second direction that is perpendicular to the first direction is its lateral direction, and the electrode terminal is provided on the second surface, and the insulating sheet has a bent portion that reaches from the first surface to the second surface of the outer can, and the bent portion includes a peak portion that protrudes from the first surface side toward the electrode terminal along the first direction and a valley portion that is located on both sides of the peak portion in the second direction and is recessed toward the side away from the electrode terminal, and the insulating sheet is a shrink film that has been shrunk by heat. [Effects of the Invention]

[0007] According to the present technology, it is possible to provide a battery cell in which the insulating sheet covering the outer can is prevented from interfering with surrounding components. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view showing the configuration of a battery cell. [Figure 2] FIG. 2 is a plan view showing an insulating sheet provided on the outer surface of the outer can. [Figure 3] FIG. 10 is a view showing a roll of a bag-shaped sheet material for forming an insulating sheet. [Figure 4] FIG. 2 is a top view showing the shoulder of the outer can. [Figure 5] FIG. 2 is a perspective view showing a shoulder portion of an outer can. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0010] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

[0011] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0012] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0013] In this specification, the term "battery" is not limited to lithium-ion batteries and may include other batteries such as nickel-metal hydride batteries. In this specification, the term "electrode" may collectively refer to positive and negative electrodes. Furthermore, the term "electrode plate" may collectively refer to positive and negative plates.

[0014] In this specification, when the terms "storage cell" or "storage module" are used, the "storage cell" or "storage module" is not limited to a battery cell or battery module, but may also include a capacitor cell or capacitor module.

[0015] 1 is a perspective view showing the configuration of a battery cell 100. The battery cell 100 is, for example, a lithium ion battery.

[0016] As shown in FIG. 1, the battery cell 100 has an electrode terminal 110, a housing 120 (external can), a gas release valve 130, and an electrolyte injection part 140.

[0017] The electrode terminals 110 are formed on the housing 120. The electrode terminals 110 include a positive electrode terminal 111 and a negative electrode terminal 112 as two electrode terminals 110 arranged along a first direction (X direction). The positive electrode terminal 111 and the negative electrode terminal 112 are provided spaced apart from each other in the X direction.

[0018] The housing 120 has a rectangular parallelepiped shape (a square shape) and forms the exterior of the battery cell 100. An electrode assembly and an electrolyte (not shown) are housed in the housing 120. The housing 120 is an exterior can having an upper surface 121, a lower surface 122, long side surfaces 123 and 124, and short side surfaces 125 and 126. The long side surfaces 123 and 124 face each other along a second direction (Y direction) that is perpendicular to the first direction (X direction).

[0019] The electrode terminals 110 are disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along a third direction (Z direction) that is perpendicular to the first direction (X direction) and the second direction (Y direction). The upper surface 121 and the lower surface 122 are flat surfaces that are perpendicular to the Z direction.

[0020] The long sides 123, 124 are flat surfaces perpendicular to the Y direction. The long sides 123, 124 have the largest area of the multiple sides of the housing 120. The long sides 123, 124 have a rectangular shape when viewed from the Y direction. When viewed from the Y direction, the long sides 123, 124 have a rectangular shape with the X direction as the longitudinal direction and the Z direction as the lateral direction.

[0021] The multiple battery cells 100 are stacked such that the long sides 123 and long sides 124 of the battery cells 100 adjacent to each other in the Y direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y direction in which the multiple battery cells 100 are stacked.

[0022] Gas exhaust valve 130 is provided on top surface 121. When the internal pressure of housing 120 exceeds a predetermined value due to gas generated inside housing 120, gas exhaust valve 130 exhausts the gas to the outside of housing 120.

[0023] The electrolyte injection part 140 is provided on the upper surface 121. The electrolyte injection part 140 includes an injection hole that penetrates the upper surface 121 and communicates with the inside of the housing 120, and a rivet that closes the injection hole. After the electrolyte is injected into the inside of the housing 120 through the injection hole, the injection hole is closed with the rivet.

[0024] The shoulder portion 150 is a region on the upper surface 121 of the housing 120 that is located further outward in the X direction than the electrode terminals 110. The shoulder portion 150 includes a shoulder portion 151 on the positive terminal 111 side and a shoulder portion 152 on the negative terminal 112 side.

[0025] 2 is a plan view showing a film 200 (insulating sheet) provided on the outer surface of the housing 120. As shown in FIG. 2, the film 200 includes a main body 210 and a protruding portion 220 that protrudes in the Z direction from the main body 210. The protruding portion 220 has protruding portions 221 and 222 located at both ends in the X direction. The battery cell 100 is housed in the bag-shaped main body 210. The protruding portion 220 is folded toward the top surface 121 of the housing 120.

[0026] The film 200 is a shrink film that shrinks when heated, and can be made of a PET (polyethylene terephthalate) material having a thickness of about 0.07 mm, for example.

[0027] After the battery cells 100 are housed in the bag-shaped film 200, the excess length of the film 200 is passed through a shrink oven to cause thermal shrinkage, which causes the film 200 to adhere tightly to the outer surface of the battery cells 100.

[0028] 3 is a diagram showing a roll 200A of a bag-shaped sheet material for forming the film 200. The bag-shaped film 200 can be formed by cutting the roll 200A, which is continuous in the Z direction, into pieces of a predetermined length.

[0029] FIG. 4 is a top view showing shoulder portion 150, and FIG. 5 is a perspective view of shoulder portion 150. As shown in FIGS. 4 and 5, film 200 provided on the outer surface of housing 120 is formed so as to cover long side surfaces 123, 124 and short side surfaces 125, 126 of housing 120. Protruding portion 220 (folded portion) of film 200 includes peaks 230 that protrude from the short side surfaces 125, 126 toward electrode terminal 110 along a first direction (X direction), and valleys 240 that are located on both sides of peaks 230 in a second direction (Y direction) perpendicular to the X direction and are recessed toward the electrode terminal 110. At valleys 240, upper surface 121 is not covered by film 200, and upper surface 121 is exposed.

[0030] In the examples of FIGS. 4 and 5, the contour of the top of the peak portion 230 has a substantially flat portion along the second direction (Y direction). "Substantially flat" does not mean completely flat, but may include a slight curve. However, the top of the peak portion 230 may be pointed. The top of the peak portion 230 is located at a position spaced apart from the electrode terminal 110 along the first direction (X direction).

[0031] When the film 200 is thermally shrunk, the film 200 may be deformed into an unintended shape. For example, if the film 200 does not form the valley portions 240 (exposed portions) and shrunk while overlapping on the upper surface 121 of the housing 120, the deformed film 200 may protrude in the Z direction, and may interfere with other components (peripheral components) that make up the battery module, such as separator members provided between adjacent battery cells 100.

[0032] From the perspective of precisely controlling the dimensions after heat shrinkage, it is possible to form a box-shaped film instead of the bag-shaped film 200 shown in Figure 2. Forming a box-shaped film allows for more precise control than by controlling the insertion amount of the battery cells 100 into the main body 210 of the bag-shaped film 200. However, there are concerns that using a box-shaped film will complicate the manufacturing process and increase manufacturing costs.

[0033] In contrast, with the film 200 according to this embodiment, the main body 210 and the protruding portions 220 are formed so that valleys 240 (exposed portions) are formed on both sides of the peaks 230, which prevents the film 200 from overlapping and shrinking on the top surface 121 of the housing 120 of the battery cell 100. As a result, unintended excessive protrusion of the film 200 is prevented, and interference with surrounding components is suppressed. As a result, it is possible to prevent a deterioration in the function of the separator between the battery cells 100 and poor welding between the bus bars that electrically connect the battery cells 100 and the electrode terminals 110 due to variations in the heights of the battery cells 100.

[0034] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0035] 100 battery cell, 110 electrode terminal, 111 positive terminal, 112 negative terminal, 120 housing, 121 upper surface, 122 lower surface, 123, 124 long side, 125, 126 short side, 130 gas release valve, 140 electrolyte injection part, 150, 151, 152 shoulder part, 200 film, 200A roll, 210 main body part, 220, 221, 222 protrusion part, 230 ridge part, 240 valley part.

Claims

1. An electrode body; a rectangular parallelepiped outer can housing the electrode assembly and having an outer surface; an electrode terminal provided on the outer surface of the outer can; a film-like insulating sheet provided on the outer surface of the exterior can, the outer surface of the outer can includes a first surface perpendicular to a first direction, a second surface perpendicular to the first surface, the second surface having a shape in which the first direction is a longitudinal direction and a second direction perpendicular to the first direction is a lateral direction, and a third surface perpendicular to the first surface and the second surface, the third surface having an area larger than the first surface and the second surface; the electrode terminal is provided on the second surface, the insulating sheet has a bent portion that extends from the first surface to the second surface of the outer can, the bent portion includes a peak portion that protrudes from the first surface side toward the electrode terminal along the first direction, and a valley portion that is located on both sides of the peak portion in the second direction and is recessed in a direction away from the electrode terminal, A battery cell, wherein the insulating sheet is a shrink film that is shrunk by heat.

2. The battery cell according to claim 1 , wherein in the valley portion, the second surface is not covered by the insulating sheet and is exposed.

3. The battery cell according to claim 1 or 2, wherein the bent portions are formed on shoulder portions on both sides of the second surface in the first direction.

4. The battery cell according to claim 1 , wherein an electrolyte injection portion is provided on the second surface of the outer can.

5. A battery cell described in any one of claims 1 to 4, wherein the insulating sheet covers at least the first surface and the third surface of the outer can.

6. The battery cell according to claim 1 , wherein the contour of the top of the ridge portion has a substantially flat portion along the second direction.

7. The battery cell according to claim 6 , wherein the top portion is located at a position spaced apart from the electrode terminal along the first direction.

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