Battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, in particular to a battery cell and a battery pack. The battery cell comprises a cover plate assembly which comprises a cover plate main body and a pole assembly mounted on the cover plate main body; the shell is in welded connection with the cover plate main body, so that a welding part is formed between the cover plate main body and the shell, and part of the welding part protrudes out of the outer wall of the shell; the insulating film covers the circumferential outer wall of the shell, one surface, facing the cover plate main body and facing the outer part of the shell, of part of the insulating film is bent to form a flanging part, the size of the flanging part in the first direction is S, and S is greater than or equal to A + T2 + (B-C) is greater than or equal to 2.5 mm. According to the utility model, the cover plate main body can be effectively coated by the insulating film, the characterization of poor appearance such as edge warping, leakage, damage and the like is avoided, the risk of insulation failure is reduced to a certain extent, the production yield of a battery cell is improved, and the use safety performance of the battery cell and a battery pack is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cell and a battery pack. Background Art

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the use performance and safety of lithium-ion batteries are increasing day by day. The outer insulating film of the lithium battery is a core component for safety and assembly, and its structural design is crucial for the safety of the battery cell. In the existing insulating film structure, after wrapping the battery cell, it is easy to have appearance defects such as warping and leaking seams. The weld between the cover plate and the housing of the battery is also easy to pierce the insulating film, resulting in an increased risk of insulation failure and affecting the safety of the battery cell. In addition, the current encapsulation process requirements for the insulating film are too high, resulting in low production efficiency and high costs, which is not conducive to the automated production of battery cells. Summary of the Utility Model

[0003] In view of this, the purpose of this application is to provide a battery cell and a battery pack to solve the problems that the insulating film wrapped outside the existing battery cell is prone to appearance defects such as warping and leaking seams, and is prone to insulation failure, affecting the use safety of the battery cell.

[0004] The first aspect of the utility model provides a battery cell, wherein the battery cell includes:

[0005] A cover plate assembly, including a cover plate main body and a pole column assembly installed on the cover plate main body;

[0006] A housing, which is welded to the cover plate main body to form a welding part between the cover plate main body and the housing, and part of the welding part protrudes from the outer wall of the housing;

[0007] An insulating film, which is wrapped around the outer wall of the housing in the circumferential direction, and part of the insulating film is bent towards the side of the cover plate main body facing the outside of the housing to form a flanging part, and the size of the flanging part in the first direction is S, S≥A+T2+(B-C)≥2.5mm;

[0008] Wherein, A is the height dimension of the welding part protruding from the outer wall of the housing in the first direction, with the unit of mm; T2 is the thickness dimension of the insulating film, with the unit of mm; B is the distance between the edge of the cover plate main body and the pole column assembly in the first direction, with the unit of mm; C is the distance between the flanging part and the pole column assembly in the first direction, with the unit of mm.

[0009] Preferably, A≤1.25×T1, where T1 is the wall thickness dimension of the housing.

[0010] Preferably, 0.25mm<T1<0.8mm.

[0011] Preferably, C ≥ 0.25 mm.

[0012] Preferably, A < 1 mm.

[0013] Preferably, the flanging portion is formed into an annular structure surrounding the edge of the cover plate body, and the inner ring and the outer ring of the annular structure are concentric rings.

[0014] Preferably, a boss is formed on the circumferential side wall of the cover plate body, and the top wall of the housing is welded to the side of the boss facing the inside of the battery cell, so that the portion of the welding part protruding from the housing surrounds the outer wall of the housing;

[0015] Part of the cover plate body is embedded inside the housing.

[0016] Preferably, the pole column assembly includes:

[0017] A pole column body, and part of the pole column body is arranged outside the battery cell;

[0018] A first insulating member, which is arranged between the pole column body and the cover plate body; B is the distance between the edge of the cover plate body and the first insulating member; C is the distance between the flanging portion and the first insulating member.

[0019] Preferably, a liquid injection hole and / or a pressure relief member are further arranged on the cover plate body, and there is a gap between the flanging portion and the liquid injection hole, and / or there is a gap between the flanging portion and the pressure relief member.

[0020] In a second aspect of the present invention, a battery pack is provided, including the battery cell according to any one of the above technical solutions.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] For the battery cell of the present invention, the insulating film is coated on the outer wall of the housing, and part of the insulating film is bent towards the side of the cover plate body facing the outside of the housing to form a flanging portion. The size of the flanging portion in the first direction is S. By defining S ≥ A + T2 + (B - C) ≥ 2.5 mm, the effective coating of the cover plate body by the insulating film is ensured, and appearances such as warping, leakage, and breakage are avoided. The risk of insulation failure is reduced to a certain extent, the production yield of the battery cell is improved, and the safety performance of the battery cell and the battery pack is improved.

[0023] In order to make the above objects, features, and advantages of the present application more obvious and understandable, the following specific embodiments are given specifically, and in conjunction with the accompanying drawings, the detailed description is as follows. Description of the Drawings

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 Schematic structural diagram of the battery cell provided by an embodiment of the present invention;

[0026] Figure 2 Schematic structural diagram of the battery cell provided by an embodiment of the present invention from another perspective;

[0027] Figure 3 For Figure 2 the enlarged structural diagram at position A in

[0028] Figure 4 For Figure 2 the cross-sectional view taken along line B-B in

[0029] Reference numerals: 10 - cover plate assembly; 11 - cover plate main body; 111 - boss; 112 - liquid injection hole; 20 - terminal assembly; 21 - terminal main body; 22 - connecting member; 23 - first insulating member; 24 - second insulating member; 30 - housing; 40 - welding part; 50 - insulating film; 51 - flanging part; D1 - first direction. Specific Embodiments

[0030] The following specific embodiments are provided to assist the reader in obtaining a comprehensive understanding of the methods, devices, and / or systems described herein. However, after understanding the disclosure of this application, various changes, modifications, and equivalents of the methods, devices, and / or systems described herein will be apparent. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein. Rather, changes that will be apparent after understanding the disclosure of this application can be made, except for operations that must occur in a specific order. In addition, for the sake of clarity and conciseness, descriptions of features known in the art may be omitted.

[0031] The features described herein can be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many possible ways of implementing the methods, devices, and / or systems described herein that will be apparent after understanding the disclosure of this application.

[0032] Throughout the specification, when an element such as a layer, region, or substrate is described as being "on" another element, "connected to" another element, "coupled to" another element, "over" another element, or "covering" another element, it can be directly "on" the other element, "connected to" the other element, "coupled to" the other element, "over" the other element, or "covering" the other element, or there can be one or more other elements intervening therebetween. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly coupled to" another element, "directly over" another element, or "directly covering" another element, there can be no other elements intervening therebetween.

[0033] As used herein, the term "and / or" includes any one of the listed related items and any combination of any two or more of them.

[0034] Although terms such as "first", "second", and "third" may be used herein to describe various components, elements, regions, layers, or sections, these components, elements, regions, layers, or sections are not limited by these terms. Rather, these terms are only used to distinguish one component, element, region, layer, or section from another. Thus, the first component, element, region, layer, or section described in the examples herein may also be referred to as the second component, element, region, layer, or section without departing from the teachings of the examples.

[0035] For ease of description, spatial relationship terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another as shown in the figures. Such spatial relationship terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "above" or "upper" relative to another element will then be "below" or "lower" relative to the other element. Thus, the term "above" includes both the orientation of "above" and "below" depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relationship terms used herein will be interpreted accordingly.

[0036] The terms used herein are for describing various examples only and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. The terms "comprising", "including" and "having" enumerate the stated features, quantities, operations, components, elements and / or combinations thereof that exist, but do not preclude the existence or addition of one or more other features, quantities, operations, components, elements and / or combinations thereof.

[0037] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Accordingly, the examples described herein are not limited to the specific shapes shown in the drawings, but include changes in shape that occur during manufacturing.

[0038] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. Additionally, although the examples described herein have various configurations, other configurations are possible, as will be apparent after understanding the disclosure of the present application.

[0039] According to a first aspect of the present utility model, a battery cell is provided, which specifically includes a cover plate assembly 10, a housing 30, and an insulating film 50.

[0040] Hereinafter, the specific structure of the battery cell according to the present embodiment will be described.

[0041] In the present embodiment, as Figure 1 and Figure 2 shown, the cover plate assembly 10 includes a cover plate main body 11 and a pole column assembly 20 mounted on the cover plate main body 11. The cover plate main body 11 is formed into a plate-like structure. Specifically, the cover plate main body 11 may be a rectangular or circular plate-like structure. The interior of the housing 30 is formed into a cavity structure capable of containing the electrode group. The cover plate main body 11 is welded to the housing 30 to enclose the housing 30, and a welding portion 40 is formed between the cover plate main body 11 and the housing 30. The welding portion 40 can be understood as a weld formed under the welding process, and a part of the welding portion 40 protrudes from the outer wall of the housing 30.

[0042] More specifically, as Figure 4 shown, a boss 111 is formed on the circumferential side wall of the cover plate main body 11. The top wall of the housing 30 is welded to the side of the boss 111 facing the interior of the battery cell, such that the part of the welding portion 40 protruding from the housing 30 surrounds the outer circumferential wall of the housing 30; and such that a part of the cover plate main body 11 is embedded inside the housing 30. In the present embodiment, the edge of the boss 111 is flush with the outer wall of the housing 30.

[0043] In the present embodiment, as Figures 1 to 4As shown, the insulating film 50 is formed of an insulating material, such as PET. The insulating film 50 is wrapped around the outer circumferential wall of the housing 30 to play a role in insulating and protecting the battery cell. The end of the insulating film 50 in the length direction of the housing 30 is bent towards the side of the cover body 11 facing the outside of the housing 30 to form a flanging portion 51. The dimension of the flanging portion 51 in the first direction D1 is S, that is, the width dimension of the flanging portion 51 is S, and S≥A + T2+(B - C)≥2.5 mm; where A is the height dimension of the welding portion 40 protruding from the outer wall of the housing 30 in the first direction D1, in mm; T2 is the thickness dimension of the insulating film 50, in mm; B is the distance between the edge of the cover body 11 and the pole assembly 20 in the first direction D1, in mm; C is the distance between the flanging portion 51 and the pole assembly 20 in the first direction D1, in mm. In this way, the dimension S of the flanging portion 51 is associated with A, T2, B, and C, ensuring the effective wrapping of the insulating film 50 around the cover body 11, avoiding appearance defects such as warping, gaps, and breakage, reducing the risk of insulation failure to a certain extent, and improving the safety performance of the battery cell during use.

[0044] Specifically, as Figures 1 to 4 shown, the flanging portion 51 is formed as an annular structure surrounding the edge of the cover body 11. When the cover body 11 is a rectangular plate-like structure, the flanging portion 51 can be a rectangular ring. When the cover body 11 is a circular plate-like structure, the flanging portion 51 can be a circular ring. The inner ring (i.e., the inner wall of the annular structure) and the outer ring (i.e., the outer wall of the annular structure) of the annular structure are concentric rings, that is, the inner ring and the outer ring of the annular structure are coaxially arranged, so that the flanging portion 51 is formed as an axisymmetric structure, ensuring the wrapping reliability of the flanging portion 51 around the cover body 11 and avoiding an increased risk of warping due to a too-narrow local dimension of the flanging portion 51.

[0045] In this embodiment, the first direction D1 can be the length direction of the rectangular cover body 11 or the width direction of the rectangular cover body 11. Figure 4 FIG. is a schematic diagram of an embodiment where the first direction D1 is the width direction of the cover body 11.

[0046] More specifically, in this embodiment, as Figures 1 to 4As shown, the terminal assembly 20 includes a terminal body 21, a first insulating member 23, and a connecting member 22. The terminal body 21 is assembled to the cover body 11. Part of the terminal body 21 is disposed outside the battery cell, and part of the terminal body 21 is disposed inside the battery cell for connecting the electrode group, thereby realizing the energy transmission inside and outside the battery cell. The connecting member 22 is provided with a riveting hole. The terminal body 21 and the connecting member 22 are first riveted and then welded to fix the terminal body 21 on the cover body 11. The first insulating member 23 is disposed between the terminal body 21 and the cover body 11 to provide insulating protection for the cover body 11 and prevent a short circuit caused by the cover body 11 being in contact with metal.

[0047] In this embodiment, in the thickness direction of the cover assembly 10, the first insulating member 23 is disposed between the connecting member 22 and the cover body 11. Part of the first insulating member 23 extends towards the outside of the battery cell to surround the circumferential sidewall of the connecting member 22, thereby realizing effective insulating protection. Specifically, B is the distance between the edge of the cover body 11 and the sidewall of the first insulating member 23; C is the distance between the flanging portion 51 and the sidewall of the first insulating member 23.

[0048] Furthermore, in this embodiment, as Figure 4 shown, A ≤ 1.25 × T1, where T1 is the wall thickness dimension of the housing 30, thereby preventing the welding portion 40 from protruding too much from the housing 30, which may cause a reduction in welding strength, cracks or even fractures in the welding portion 40, as well as poor encapsulation or damage to the insulating film 50, and improving the production quality of the battery cell.

[0049] In a preferred embodiment, as Figure 4 shown, A < 1 mm, thereby effectively preventing the welding portion 40 from piercing the insulating film 50, effectively reducing the risk of insulation failure, and ensuring the safety performance of the battery cell during use.

[0050] Even further, in this embodiment, 0.25 mm < T1 < 0.8 mm, thereby preventing the wall thickness dimension of the housing 30 from being too small, which may affect the welding quality between the housing 30 and the cover body 11, and also preventing the wall thickness dimension of the housing 30 from being too large, which may cause a reduction in the battery cell capacity.

[0051] In a preferred embodiment, as Figure 4 shown, C ≥ 0.25 mm, thereby defining the minimum distance between the flanging portion 51 and the electrode group assembly, thus realizing a reasonable assembly gap, ensuring insulation while reducing the process requirements for encapsulation, improving the encapsulation efficiency, and further improving the production efficiency of the battery cell and reducing the production cost.

[0052] Furthermore, in this embodiment, the cover body 11 is further provided with a liquid injection hole 112 and / or a pressure relief member. For the structure of the liquid injection hole 112, refer to Figures 1 to 3As shown, the injection hole 112 is formed as a through-hole structure penetrating the cover body 11. After the shell 30 is welded to the cover body 11, the electrolyte can be injected into the battery cell through the injection hole 112. The cover body 11 is also provided with an exhaust hole (not shown). The exhaust hole is a through-hole structure penetrating the cover body 11. The pressure relief piece is installed on the exhaust hole. The pressure relief piece can be an explosion-proof valve. When the battery cell fails and produces gas inside, the pressure relief piece opens to allow the gas inside the battery cell to be discharged to the outside of the battery cell through the exhaust hole to relieve pressure and reduce the risk of explosion or fire of the battery cell. There is a gap between the flange portion 51 and the injection hole 112, and / or there is a gap between the flange portion 51 and the pressure relief piece, so as to avoid the injection hole 112 and / or the exhaust hole from being blocked, thereby ensuring smooth injection and / or exhaust work.

[0053] In addition, in this embodiment, if Figure 4 As shown, the cover assembly 10 also includes a second insulating member 24. The first insulating member 23 and the second insulating member 24 are both formed of insulating materials, such as PP (polypropylene) or PPS (polyphenylene sulfide). The second insulating member 24 is arranged on the side of the cover body 11 facing the inside of the battery cell to further avoid a short circuit caused by overlapping the cover body 11 or the shell 30 with the metal.

[0054] The following are the packaging of battery cells with different sizes of T1, T2, A, B, C and S, and the appearance inspection test of the coated battery cells. The test results are shown in the table below.

[0055]

[0056] As can be seen from the table above, in Examples 1 to 5, T1, T2, A, B, C and S are all within the range defined in this application, and the coated battery cells do not show signs of poor appearance. While ensuring insulation performance, the coating efficiency is increased, the coating cost is reduced, and the production yield and automation level of the battery cells are improved. In Comparative Examples 1 and 2, the flange portion 51 interferes with the assembly of the pole assembly 20, and the assembly efficiency is low, which is mainly due to the small size of C; in Comparative Examples 1 and 3, the size A of the welding portion 40 is too large relative to the size of the wall thickness T1 of the shell 30, resulting in poor appearance signs such as scratches on the insulating film 50 after coating; in Comparative Examples 2 and 3, since the size of S is less than 2.5 mm, the flange portion 51 is prone to warping.

[0057] According to a battery cell provided by the present utility model, an insulating film is wrapped around the outer circumferential wall of the housing. A part of the insulating film is bent towards the side of the cover plate body facing the outside of the housing to form a flanging portion. The size of the flanging portion in the first direction is S. By defining that S≥A + T2+(B - C)≥2.5 mm, the effective wrapping of the cover plate body by the insulating film is ensured, avoiding appearance defects such as warping, leakage, and breakage, reducing the risk of insulation failure to a certain extent, and improving the safety performance of the battery cell during use. Secondly, by defining the height dimension A of the welding portion protruding outside the housing, while ensuring the welding strength between the cover plate body and the housing, it also avoids the situation of poor film wrapping or damage to the insulating film caused by an excessive size of A, improving the production quality of the battery cell. In addition, the distance C between the flanging portion and the first insulating member is also defined to achieve a reasonable assembly gap, ensuring insulation while reducing the process requirements for film wrapping, improving the film wrapping efficiency, thereby improving the production efficiency of the battery cell and reducing the production cost.

[0058] According to a battery pack provided by the present utility model, it includes the battery cell as described above. There are multiple battery cells, and the multiple battery cells are connected in series and / or in parallel to form a battery module. The battery module is assembled inside the battery pack housing. Each battery cell in the battery pack has good insulation performance, effectively improving the safety performance of the battery pack.

[0059] Finally, it should be noted that: the above-described embodiments are only specific implementation manners of the present application, used to illustrate the technical solutions of the present application, rather than limiting them. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the technical field of the present application can still modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes, or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims

1. A battery cell, characterized in that, The battery cell includes: A cover plate assembly, including a cover plate main body and a pole column assembly mounted on the cover plate main body; A housing, welded to the cover plate main body to form a welded portion between the cover plate main body and the housing, and a part of the welded portion protrudes from the outer wall of the housing; An insulating film, covering the outer circumferential wall of the housing, and a part of the insulating film is bent toward the side of the cover plate main body facing the outside of the housing to form a flanging portion. The size of the flanging portion in the first direction is S, and S≥A + T2+(B - C)≥2.5 mm; Wherein, A is the height dimension of the welded portion protruding from the outer wall of the housing in the first direction, in mm; T2 is the thickness dimension of the insulating film, in mm; B is the distance between the edge of the cover plate main body and the pole column assembly in the first direction, in mm; C is the distance between the flanging portion and the pole column assembly in the first direction, in mm.

2. The battery cell according to claim 1, characterized in that, A≤1.25×T1, where T1 is the wall thickness dimension of the housing.

3. The battery cell according to claim 2, characterized in that 0.25 mm<T1<0.8 mm.

4. The battery cell according to claim 1, wherein C≥0.25 mm.

5. The battery cell according to claim 2, wherein, A<1 mm.

6. The battery cell according to claim 1, wherein, The flanging portion is formed into an annular structure surrounding the edge of the cover plate main body, and the inner ring and the outer ring of the annular structure are concentric rings.

7. The cell according to claim 1, characterized in that, A boss is formed on the circumferential side wall of the cover plate main body, and the top wall of the housing is welded to the side of the boss facing the inside of the battery cell, so that the part of the welded portion protruding from the housing surrounds the outer circumferential wall of the housing; A part of the cover plate main body is embedded in the housing.

8. The cell according to claim 1, characterized in that, The pole column assembly includes: A pole column main body, and a part of the pole column main body is arranged outside the battery cell; A first insulating member, arranged between the pole column main body and the cover plate main body; B is the distance between the edge of the cover plate main body and the first insulating member; C is the distance between the flanging portion and the first insulating member.

9. The battery cell according to claim 1, wherein A liquid injection hole and / or a pressure relief member are further arranged on the cover plate main body, and there is a gap between the flanging portion and the liquid injection hole, and / or there is a gap between the flanging portion and the pressure relief member.

10. A battery pack, characterized in that, Including the battery cell according to any one of claims 1 to 9.

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