Battery cell

Abstract

A battery unit in which an insulating sheet covering an outer can does not interfere with a peripheral member is provided. The battery unit (100) includes an electrode body, an outer can (120), two electrode terminals (111, 112) arranged in a first direction on an upper surface (121) of the outer can, and a film-shaped insulating sheet (200) provided on an outer surface of the outer can. The insulating sheet has a bent portion (220) reaching the upper surface from a short side (125, 126) of the outer can. The bent portion includes a ridge portion (230) protruding from the short side (125, 126) side toward the two electrode terminals (111, 112) side along the first direction, and a valley portion (240) located on both sides of a second direction orthogonal to the first direction with respect to the ridge portion (230) and recessed toward a side away from the two electrode terminals (111, 112).

Description

Technical Field

[0001] This technology relates to battery cells. Background Technology

[0002] Battery cells having an insulating film covering the outer surface of a square outer can have been known for some time. Such insulating films and battery cells having such insulating films are described, for example, in Japanese Patent Application Publication Nos. 2014-63686 and 2016-154147.

[0003] During the process of attaching the insulating film tightly to the outer can, the insulating film may sometimes deform into an unintended shape. For example, if the deformed insulating film protrudes from the top surface of the outer can, it may interfere with other components that make up the battery module. Summary of the Invention

[0004] The problem that the invention aims to solve

[0005] The purpose of this technology is to provide a battery cell that suppresses interference between the insulating sheet covering the outer can and surrounding components.

[0006] The battery cell of this technology comprises: an electrode body; a square outer can housing the electrode body and having an outer surface including a top surface, a long side surface, and a short side surface; two electrode terminals disposed on the top surface of the outer can and arranged in a first direction; and a film-like insulating sheet disposed on the outer surface of the outer can. The insulating sheet has a bent portion extending from the short side surface of the outer can to the top surface. The bent portion includes: a mountain-shaped portion protruding from the short side surface towards the two electrode terminals along the first direction; and a valley-shaped portion located on both sides of the mountain-shaped portion in a second direction orthogonal to the first direction and recessed towards the side away from the two electrode terminals.

[0007] The above and other objects, features, aspects, and advantages of the present invention will become clear from the following detailed description of the invention, which will be understood in conjunction with the accompanying drawings. Attached Figure Description

[0008] Figure 1 This is a three-dimensional view showing the structure of a battery cell.

[0009] Figure 2 This is a top view showing the insulating sheet disposed on the outer surface of the outer can.

[0010] Figure 3 This is a diagram showing a roller used to form a bag-shaped sheet of insulating material.

[0011] Figure 4 This is a top view showing the shoulder of the outer can.

[0012] Figure 5 It is a perspective view showing the shoulder of the outer can. Detailed Implementation

[0013] The embodiments of this technology will be described below. Furthermore, sometimes the same or equivalent parts are labeled with the same reference numerals, and their descriptions are not repeated.

[0014] Furthermore, in the embodiments described below, when the number, quantity, etc., are mentioned, the scope of this technology is not necessarily limited to the number, quantity, etc., unless specifically stated otherwise. Additionally, in the embodiments described below, each constituent element is not necessarily essential to this technology unless specifically stated otherwise. Furthermore, this technology is not limited to fully achieving the effects mentioned in these embodiments.

[0015] It should be noted that in this specification, terms such as "comprise," "include," and "have" are open-ended. That is, when including a certain structure, other structures besides that structure may be included, or they may not be included.

[0016] Furthermore, in this specification, when using geometric terms and terms indicating positional / directional relationships, such as "parallel," "orthogonal," "tilted at 45°," "coaxial," and "along," these terms are permissible to have slight errors or variations. In this specification, when using terms indicating relative positional relationships such as "upper side" and "lower side," these terms are used to indicate relative positional relationships in a given state. Depending on the orientation of each mechanism (e.g., flipping the entire mechanism up or down), the relative positional relationships can be flipped or rotated to any angle.

[0017] In this specification, "battery" is not limited to lithium-ion batteries and may include other batteries such as nickel-metal hydride batteries. In this specification, "electrode" can be collectively referred to as positive electrode and negative electrode. Additionally, "electrode plate" can be collectively referred to as positive plate and negative plate.

[0018] In this specification, when the terms "energy storage unit" or "energy storage module" are used, "energy storage unit" or "energy storage module" is not limited to battery unit or battery module, but may include capacitor unit or capacitor module.

[0019] Figure 1 This is a perspective view showing the structure of the battery cell 100. The battery cell 100 is, for example, a lithium-ion battery.

[0020] like Figure 1As shown, the battery cell 100 has electrode terminals 110, a frame 120 (outer can), a gas discharge valve 130, and an electrolyte injection section 140.

[0021] Electrode terminals 110 are formed on the frame 120. The electrode terminals 110 have a positive terminal 111 and a negative terminal 112 as two electrode terminals 110 arranged along a first direction (X direction). The positive terminal 111 and the negative terminal 112 are arranged separately from each other in the X direction.

[0022] The frame 120 has a cuboid shape (square shape), forming the appearance of the battery cell 100. Electrodes (not shown) and electrolyte are housed within the frame 120. The frame 120 is an outer casing having an upper surface 121, a lower surface 122, long sides 123 and 124, and short sides 125 and 126. The long sides 123 and 124 face each other along a second direction (Y direction) orthogonal to the first direction (X direction).

[0023] 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) orthogonal to the first direction (X direction) and the second direction (Y direction). The upper surface 121 and the lower surface 122 are planes orthogonal to the Z direction.

[0024] Long sides 123 and 124 are formed by planes orthogonal to the Y direction. Long sides 123 and 124 have the largest area among the multiple sides of the frame 120. Long sides 123 and 124 have a rectangular shape when viewed from the Y direction. Long sides 123 and 124 have a rectangular shape with the X direction as the long side and the Z direction as the short side when viewed from the Y direction.

[0025] Multiple battery cells 100 are stacked between adjacent battery cells 100 along the Y direction, with their long sides 123 facing each other and their long sides 124 facing each other. Thus, in the Y direction of the stacked battery cells 100, the positive terminal 111 and the negative terminal 112 are arranged alternately.

[0026] A gas discharge valve 130 is provided on the upper surface 121. When the internal pressure of the frame 120 exceeds a predetermined value due to the gas generated inside the frame 120, the gas discharge valve 130 discharges the gas to the outside of the frame 120.

[0027] An electrolyte injection section 140 is provided on the upper surface 121. The electrolyte injection section 140 includes an injection hole that penetrates the upper surface 121 and communicates with the interior of the frame 120, and a rivet that plugs the injection hole. After the electrolyte is injected into the interior of the frame 120 through the injection hole, the injection hole is plugged by the rivet.

[0028] The shoulder 150 is the region on the upper surface 121 of the housing 120 located on the outer side in the X direction of the electrode terminal 110. The shoulder 150 includes a shoulder 151 on the positive terminal 111 side and a shoulder 152 on the negative terminal 112 side.

[0029] Figure 2 This is a top view showing the membrane 200 (insulating sheet) disposed on the outer surface of the frame 120. (See attached image.) Figure 2 As shown, the membrane 200 includes a main body 210 and a protrusion 220 protruding from the main body 210 in the Z direction. The protrusion 220 has protrusions 221 and 222 at both ends located in the X direction. The battery unit 100 is housed in the pouch-shaped main body 210. The protrusion 220 is bent toward the upper surface 121 of the frame 120.

[0030] Film 200 is a shrink film that shrinks due to heat. Film 200 can be formed, for example, from PET (polyethylene terephthalate) raw material with a thickness of about 0.07 mm.

[0031] After the battery cell 100 is housed in the pouch-shaped membrane 200, the remaining length of the membrane 200 is heat-shrinked in a shrink oven. As a result, the membrane 200 adheres tightly to the outer surface of the battery cell 100.

[0032] Figure 3 This diagram shows a roller 200A used to form a bag-shaped sheet of film 200. By cutting the roller 200A continuously in the Z direction at predetermined lengths, a bag-shaped film 200 can be formed.

[0033] Figure 4 This is a top view showing the shoulder 150. Figure 5 This is a 3D diagram of a shoulder area of ​​150 degrees. (Example) Figure 4 , Figure 5 As shown, the membrane 200 disposed on the outer surface of the frame 120 is formed to cover the long sides 123, 124 and short sides 125, 126 of the frame 120. The protrusions 220 (bent portions) of the membrane 200 include: a mountain portion 230, which protrudes along a first direction (X direction) from the short sides 125, 126 towards the electrode terminal 110; and a valley portion 240, which is located on both sides of the mountain portion 230 in a second direction (Y direction) orthogonal to the X direction and recessed towards the side away from the electrode terminal 110. In the valley portion 240, the upper surface 121 is not covered by the membrane 200 and is exposed.

[0034] exist Figure 4 , Figure 5In the example, the top profile of the hill 230 has a generally flat portion along the second direction (Y direction). "Generally flat" does not mean completely flat, and also includes cases with slight curvature. However, the top of the hill 230 can also be sharp. The top of the hill 230 is located away from the electrode terminal 110 along the first direction (X direction).

[0035] When the membrane 200 is thermally contracted, it may sometimes deform into an unintended shape. For example, if the membrane 200 is contracted while overlapping on the upper surface 121 of the frame 120 without forming the valley 240 (exposed portion), the deformed membrane 200 may protrude in the Z direction and may interfere with other components (peripheral components) that constitute the battery module, such as the separator member disposed between adjacent battery cells 100.

[0036] From the perspective of precisely managing the dimensions after heat shrinkage, consider forming a box-shaped film instead. Figure 2 The bag-shaped membrane 200 is shown. By forming a box-shaped membrane, more precise control can be achieved compared to controlling the insertion amount of the battery cell 100 into the main body 210 of the bag-shaped membrane 200. However, using a box-shaped membrane may lead to increased complexity in the manufacturing process or increased manufacturing costs.

[0037] In contrast, according to the membrane 200 of this embodiment, since the main body 210 and the protrusion 220 are formed such that valleys 240 (exposed portions) are formed on both sides of the mountain portion 230, the situation where the membrane 200 overlaps and shrinks on the upper surface 121 of the frame 120 of the battery cell 100 is suppressed. As a result, unintended excessive protrusion of the membrane 200 can be suppressed, and interference with surrounding components can be suppressed. As a result, the functional degradation of the separator between the battery cells 100 or poor welding of the busbars connecting the multiple battery cells 100 to the electrode terminals 110 due to uneven height of the multiple battery cells 100 can be suppressed.

[0038] Embodiments of the present invention have been described, but should be considered illustrative rather than limiting in all respects. The scope of the invention is set forth in the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery cell, wherein, The battery cell includes: Electrode body; A square outer container, the square outer container housing the electrode body, and having an outer surface including a top surface, a long side surface and a short side surface; Two electrode terminals are disposed on the upper surface of the outer can and arranged in a first direction; as well as A film-like insulating sheet is disposed on the outer surface of the outer packaging can. The insulating sheet has a bend extending from the short side of the outer can to the upper surface. The bending portion includes a mountain portion that protrudes from the short side side toward the two electrode terminals along the first direction; And the valley portion, which is located on both sides of the mountain portion in a second direction orthogonal to the first direction and recessed towards the side away from the two electrode terminals. The insulating sheet is not overlapped at the mountain-shaped portion on the outer surface of the outer can.

2. The battery cell according to claim 1, wherein, The insulating sheet is a shrink film that shrinks due to heat.

3. The battery cell according to claim 1 or 2, wherein, The insulating sheet covers at least the long side and the short side of the outer can.

4. The battery cell according to claim 1 or 2, wherein, The top of the mountain has a flat portion along the second direction.

5. The battery cell according to claim 4, wherein, The top is located away from the two electrode terminals along the first direction.

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