Battery cell shell and battery cell

Abstract

The invention relates to the technical field of batteries, in particular to a battery cell shell and a battery cell. A containing cavity is formed in the battery cell shell, the side wall of the battery cell shell comprises a thickening area and a body area which are arranged in the depth direction of the containing cavity, one side, facing the containing cavity, of the thickening area protrudes inwards, so that the thickness of the side wall of the thickening area is larger than that of the side wall of the body area, and the thickening area is arranged at an opening of the containing cavity. The battery cell shell is of a shell structure with unequal wall thickness, and the wall thickness of the side wall in the thickening area is relatively large, so that the battery cell cover plate and the battery cell shell have enough fusion width after being welded, the welding strength of the battery cell shell and the battery cell cover plate is improved, the production yield of the battery cell is further improved, and the production cost is reduced. The weight of the battery cell is not excessively increased while the manufacturability of the battery cell is improved; the wall thickness of the side wall in the body area is relatively small. The internal space of the battery cell is not occupied, the situation that the capacity of the battery cell is reduced due to increase of the wall thickness is avoided, and the requirement of a user for the capacity of the battery cell is met.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell shell and a battery cell. Background Art

[0002] As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of lithium-ion batteries are increasing.

[0003] The shell is an important component of the lithium battery. It is used to carry the battery cell electrode group and can be assembled and welded with the cover plate to form a sealed battery cell space. Since the size of the battery pack is limited by the space layout of the whole vehicle, the external dimensions of the battery cell also have limited specifications. Therefore, the thickness of the shell wall will directly affect the capacity of the battery cell. In the prior art, the shell is a uniform wall thickness structure. If the shell wall thickness is too large, the battery cell will expand severely after charging and discharging, which will affect the performance of the battery cell. At the same time, the excessive thickness of the shell wall will also cause the battery cell capacity to become smaller and the shell weight to increase, which is not conducive to the competitiveness of the product. However, if the shell wall thickness is too small, the welding strength between the shell and the cover plate is insufficient, and cracks are likely to occur at the connection between the shell and the cover plate, so the safety performance and service life of the battery cell cannot be guaranteed. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a battery cell shell and a battery cell to solve the problem that the existing battery cell shell has a uniform wall thickness structure, and the wall thickness of the shell is too large, which has the defects of reducing the battery cell capacity and increasing the weight of the shell, and the wall thickness of the shell is too small, which affects the welding strength between the shell and the cover plate, making it easy for cracks to occur at the connection between the shell and the cover plate, thereby failing to guarantee the safety performance and service life of the battery cell.

[0005] A first aspect of the present invention provides a battery cell shell, wherein a accommodating cavity is formed inside the battery cell shell, and the side wall of the battery cell shell includes a thickened area and a main body area arranged along the depth direction of the accommodating cavity, and the thickened area protrudes inwardly on a side facing the accommodating cavity, so that the thickness of the side wall of the thickened area is greater than the thickness of the side wall of the main body area, and the thickened area is arranged at the opening of the accommodating cavity.

[0006] Preferably, the thickness dimension of the side wall of the body region is t, 0.35 mm≤t≤0.65 mm.

[0007] Preferably, the thickness dimension of the side wall of the thickened area is t1, and 1.1≤t1 / t≤1.7.

[0008] Preferably, the dimension of the thickened area in the depth direction of the accommodating cavity is h1, 1mm≤h1≤2mm.

[0009] Preferably, the side wall of the battery cell housing along the depth direction of the accommodating cavity further includes a transition zone arranged between the thickened area and the body area, and the transition zone forms a transition portion on a side facing the accommodating cavity.

[0010] Preferably, the transition portion is arranged to be inclined, and an angle between the transition portion and the depth direction of the accommodating cavity is θ, 10°≤θ≤30°.

[0011] Preferably, the total dimension of the transition zone and the thickened zone in the depth direction of the accommodating cavity is h2, and 3.5 mm≤h2≤5.5 mm.

[0012] Preferably, a side of the side wall of the thickened area facing the accommodating cavity is formed as a first cavity wall, a first fillet is provided between the transition portion and the first cavity wall, and the radius of the first fillet is R1, 1mm≤R1≤5mm; And / or, a side of the side wall of the main body region facing the accommodating cavity is formed as a second cavity wall, a second fillet is provided between the transition portion and the second cavity wall, and the radius of the second fillet is R2, 1mm≤R2≤5mm.

[0013] Preferably, the battery cell housing comprises a first side wall and a second side wall, the area of ​​the first side wall is greater than the area of ​​the second side wall, and the thickened area is arranged on the first side wall. A second aspect of the present invention provides a battery cell, comprising the battery cell shell described in any one of the above technical solutions.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The battery cell shell of the present invention has a side wall comprising a thickened area and a main body area arranged along the depth direction of the accommodating cavity, the thickened area protrudes inwardly on the side facing the accommodating cavity, so that the thickness of the side wall of the thickened area is greater than the thickness of the side wall of the main body area, the thickened area is arranged at the opening of the accommodating cavity, so that the battery cell shell is formed into a shell structure with unequal wall thicknesses, and the battery cell cover plate is assembled at the opening of the accommodating cavity. Since the wall thickness of the side wall in the thickened area is relatively large, the battery cell cover plate and the battery cell shell have sufficient weld width after welding, thereby improving the welding strength of the battery cell shell and the battery cell cover plate, thereby improving the production yield of the battery cell, and will not excessively increase the weight of the battery cell while improving the manufacturing processability of the battery cell; the pole group is assembled in the main body area, and the wall thickness of the side wall in the main body area is relatively small, so it will not occupy the space inside the battery cell, thereby avoiding the situation where the battery cell capacity is reduced due to increased wall thickness, thereby meeting the user's demand for battery cell capacity.

[0015] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the structure of a battery cell housing provided in an embodiment of the present invention; Figure 2 A structural cross-sectional view of a battery cell housing provided by an embodiment of the present invention; Figure 3 for Figure 2 Schematic diagram of the structure enlarged at point A in the middle.

[0018] Icon: 101-first side wall; 102-second side wall; 103-bottom wall; 100-accommodating cavity; 110-thickened area; 111-first cavity wall; 120-transition area; 121-transition part; 130-main body area; 131-second cavity wall; 140-first rounded corner; 150-second rounded corner. DETAILED DESCRIPTION

[0019] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present 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 an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0020] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been 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 the present application.

[0021] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0022] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0023] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0024] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations 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 relational terms used herein will be interpreted accordingly.

[0025] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0026] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0027] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0028] According to a first aspect of the present invention, a battery cell case is provided.

[0029] Hereinafter, a specific structure of the cell case according to the present embodiment will be described.

[0030] In this embodiment, if Figure 1 and Figure 2 As shown, a receiving cavity 100 is formed inside the battery cell shell for accommodating the electrode group. The side wall of the battery cell shell includes a thickened area 110 and a main body area 130 arranged along the depth direction of the receiving cavity 100. The depth direction of the receiving cavity 100 is the direction in which the electrode group is inserted into the battery cell shell. The thickened area 110 protrudes inwardly on the side facing the receiving cavity 100, so that the thickness of the side wall of the thickened area 110 is greater than the thickness of the side wall of the main body area 130, that is, a boss structure is formed on the inner side of the side wall of the thickened area 110, so that the battery cell shell forms a shell structure of unequal thickness in which the wall thickness of the thickened area 110 is greater than the wall thickness of the main body area 130.

[0031] Specifically, the thickened area 110 is arranged at the opening of the accommodating cavity 100, so that the opening of the accommodating cavity 100 is formed into a constricted structure. The cell cover is assembled at the opening of the accommodating cavity 100, and is welded to the cell shell so that the accommodating cavity 100 is formed into a closed cavity structure. Since the wall thickness of the side wall in the thickened area 110 is relatively large, the cell cover and the cell shell have sufficient weld width after welding, thereby improving the welding strength of the cell shell and the cell cover, further improving the manufacturing yield of the cell shell and the cell cover under the high-speed welding process, improving the manufacturing processability of the cell without excessively increasing the weight of the cell.

[0032] In this embodiment, the cell shell and the cell cover are in an embedded butt-welded manner, that is, the circumferential side wall of the cell cover is butt-welded to the cavity wall at the opening of the accommodating cavity 100 .

[0033] More specifically, the main structure of the electrode group is assembled in the main body area 130. Since the wall thickness of the side wall in the main body area 130 is relatively small, it will not occupy the space inside the battery cell, avoiding the situation where the volume of the accommodating cavity 100 is reduced due to increased wall thickness, thereby ensuring that the battery cell capacity meets user needs.

[0034] Furthermore, in this embodiment, if Figure 2 and Figure 3 As shown, the thickness dimension of the side wall of the main body area 130 is t, 0.35mm≤t≤0.65mm, which ensures that the battery cell shell has sufficient structural strength and can also ensure that the battery cell capacity meets the battery cell usage requirements.

[0035] Furthermore, in this embodiment, if Figure 2 and Figure 3 As shown, the thickness dimension of the side wall of the thickened area 110 is t1, in mm; 1.1≤t1 / t≤1.7, so as to ensure that the battery cell shell and the battery cell cover can fit closely and be reliably connected, and avoid the side wall of the thickened area 110 being too little thickened, resulting in no obvious effect on improving the welding yield and process efficiency, and can also avoid the side wall of the thickened area 110 being too much thickened, which affects the entry of the pole group into the shell, makes the battery cell shell difficult to process and form, and is prone to local material shortage and edge collapse, thereby causing the battery cell shell and the battery cell cover to have laser ablation of the insulating protective layer on the pole group during welding, causing battery cell failure.

[0036] In a preferred embodiment, Figure 2 and Figure 3 As shown, the dimension of the thickened area 110 in the depth direction of the accommodating cavity 100 is h1, 1mm≤h1≤2mm, so that the battery cover and the battery shell have sufficient melting depth after welding, thereby further improving the welding strength and welding quality of the battery cover and the battery shell, and avoiding defects such as molten beads during the welding process.

[0037] In this embodiment, if Figure 2 and Figure 3 As shown, the side wall of the battery cell shell along the depth direction of the accommodating cavity 100 also includes a transition zone 120 arranged between the thickened zone 110 and the main body zone 130, and the side of the transition zone 120 facing the accommodating cavity 100 is formed as a transition portion 121 to play a guiding role, so that the thickened zone 110 and the main body zone 130 with unequal wall thickness can be naturally and smoothly connected.

[0038] Preferably, the thickened area 110, the transition area 120 and the main body area 130 are all formed into annular structures, so that the entire circumference of the opening of the accommodating cavity 100 is thickened, thereby ensuring that the weld formed by the battery cover and the battery shell after welding has sufficient weld width and depth as a whole.

[0039] In a preferred embodiment, Figure 3 As shown, the transition portion 121 is inclined so that the transition portion 121 forms a slope structure, and the angle between the transition portion 121 and the depth direction of the accommodating cavity 100 is θ, 10°≤θ≤30°. If θ is too small, the transition portion 121 in the depth direction of the accommodating cavity 100 will be too long, affecting the space in the accommodating cavity 100 after the pole group expands, and resulting in a smaller distance between the first cavity wall 111 and the outer wall of the battery cell shell as described below, which is prone to laser leakage when welding with the battery cell cover, resulting in insulation failure inside the battery cell. If θ is too large, the guiding effect of the transition portion 121 is not ideal, so that the side wall of the thickened area 110 is excessively protruding.

[0040] Furthermore, in this embodiment, if Figure 3 As shown, the total dimension of the transition zone 120 and the thickened zone 110 in the depth direction of the accommodating cavity 100 is h2, that is, h2 is the sum of the dimension h1 of the thickened zone 110 in the depth direction of the accommodating cavity 100 and the dimension of the transition zone 120 in the depth direction of the accommodating cavity 100. Preferably, 3.5mm≤h2≤5.5mm, so as to ensure smooth entry of the pole into the shell and avoid the situation where the diaphragm on the outside of the pole group is scratched and wrinkled or even damaged.

[0041] Furthermore, in this embodiment, if Figure 3 As shown, the side of the side wall of the thickened area 110 facing the accommodating cavity 100 is formed as a first cavity wall 111. The first cavity wall 111 can be understood as the side of the side wall of the thickened area 110 facing the inside of the battery cell. A first fillet 140 is arranged between the transition portion 121 and the first cavity wall 111. The radius of the first fillet 140 is R1, 1mm≤R1≤5mm, so that the transition portion 121 and the first cavity wall 111 are smoothly connected, avoiding the appearance of edges at the junction of the transition portion 121 and the first cavity wall 111, causing the diaphragm on the outside of the pole group to be scratched and wrinkled or even damaged, ensuring the assembly quality of the battery cell, and avoiding the situation that the size of R1 is too large, resulting in difficulties in processing and molding the battery cell shell and prone to local shortage of materials, resulting in laser leakage when the battery cell shell and the battery cell cover are welded, causing the internal insulating protective layer to be ablated, and the insulation performance of the battery cell is not met. In an alternative embodiment, the first cavity wall 111 may be a planar structure extending along the depth direction of the accommodating cavity 100 .

[0042] Preferably, if Figure 3As shown, the side of the side wall of the body area 130 facing the accommodating cavity 100 is formed as a second cavity wall 131. The second cavity wall 131 can be understood as the side of the side wall of the body area 130 facing the inside of the battery cell. A second fillet 150 is provided between the transition portion 121 and the second cavity wall 131. The radius of the second fillet 150 is R2, 1mm≤R2≤5mm. In this way, the transition portion 121 and the second cavity wall 131 are smoothly connected, and the stress concentration at the junction of the transition portion 121 and the second cavity wall 131 is avoided, resulting in insufficient strength of the battery cell shell. In addition, the battery cell shell has metal wires formed during the processing. During assembly, the metal wires are easy to fall off inside the battery cell and cause overlapping problems. It also avoids the problem that the size of R2 is too large, which makes it difficult to process and form the battery cell shell and is prone to local shortage of materials, so that laser leakage occurs when the battery cell shell and the battery cell cover are welded, causing the internal insulation protection layer to be ablated, and the insulation performance of the battery cell is not met. Thereby further improving the assembly quality of the battery cell. In an optional implementation, the second cavity wall 131 may also be a planar structure extending along the depth direction of the accommodating cavity 100 , and the second cavity wall 131 is parallel to the first cavity wall 111 .

[0043] In this embodiment, if Figure 1 As shown, the battery cell shell includes a first side wall 101 and a second side wall 102, the area of ​​the first side wall 101 is larger than the area of ​​the second side wall 102, and the thickened area 110 is arranged on the first side wall 101, so that only the thickness of the side wall of the upper part of the battery cell shell is increased to ensure that the pole group can be smoothly inserted into the shell. The thickened area 110 is arranged on the first side wall 101 with a relatively large size, which can also ensure the reliability and effectiveness of the increase in wall thickness in improving the connection strength between the battery cover and the battery cell shell. Specifically, Figure 1 As shown, two first side walls 101 and two second side walls 102 are provided, and the first side walls 101 and the second side walls 102 are alternately connected to each other, so that the two first side walls 101 are arranged opposite to each other, and the two second side walls 102 are arranged opposite to each other, so that the battery cell shell forms a rectangular shell structure.

[0044] In this embodiment, if Figure 1 and Figure 2 As shown, the battery cell housing further includes a bottom wall 103, which is connected to the first side wall 101 and the second side wall 102 respectively, so that the accommodating cavity 100 has an opening on only one side, and the thickened area 110 is arranged on the side of the battery cell housing away from the bottom wall 103. The bottom wall 103, the first side wall 101 and the second side wall 102 are all formed into a plate-like structure, and the bottom wall 103, the first side wall 101 and the second side wall 102 are connected to each other to enclose the accommodating cavity 100.

[0045] Next, the battery cell shells with different size parameters of t, t1, θ, R1 and R2 are assembled with the battery cell cover to form the battery cell, and whether the assembly quality of the battery cell meets the use requirements is tested. The test results are shown in Table 1 below.

[0046] Table 1

[0047] As shown in Table 1 above, in Examples 1 to 7, t, t1 / t, θ, R1 and R2 are all within the limited ranges described above, the battery cell shell and the battery cell cover are well welded, there are no problems such as laser leakage and cold welding, and the battery cell use requirements are met.

[0048] In comparative example 1, due to the small angle of θ, laser leakage occurs during the welding of the cell shell and the cell cover, resulting in poor insulation inside the cell; in comparative example 2, due to the excessively large parameters of R1 and R2, the size of h1 on the thickened area 110 is affected, making h1 smaller than the specified range, resulting in the welding molten pool of the actual cell shell and the cell cover exceeding the thickened area 110, and laser ablation to the inner insulating protective layer of the electrode group; in comparative example 3, due to the excessively large ratio of t1 / t, the cell shell is difficult to process and form, and there is a problem of material shortage and edge collapse in some parts, and the problem of laser leakage and ablation of the inner insulating protective layer occurs during the welding of the cell shell and the cell cover; in comparative example 4, due to R2 The size of R1 is too small, and the connection between the transition zone 120 and the main body zone 130 is too sharp. After the manufacturing process, local stress concentration occurs in the battery cell shell, resulting in insufficient strength, and the metal wire is difficult to remove, resulting in the metal wire falling off inside the battery cell after the battery cell is assembled, resulting in poor internal lap insulation. In Comparative Example 5, since the size of R1 is too small, the connection between the thickened area 110 and the transition zone 120 is too sharp, and the diaphragm is scratched when the pole group is put into the shell. In Comparative Example 6, since the size of R2 is too large, the actual processing and molding of the battery cell shell is difficult, resulting in local material shortages. When the battery cell shell and the battery cell cover are welded, the material shortage points leak lasers, and the inner insulating protective layer is ablated, which does not meet the battery cell use requirements.

[0049] According to a battery cell shell provided by the present invention, the side wall of the battery cell shell includes a thickened area and a main body area arranged along the depth direction of an accommodating cavity, the side wall of the thickened area protrudes inwardly toward one side of the accommodating cavity, so that the thickness of the side wall of the thickened area is greater than the thickness of the side wall of the main body area, the thickened area is arranged at the opening of the accommodating cavity, so that the battery cell shell is formed into a shell structure with unequal wall thicknesses, and the battery cell cover plate is assembled at the opening of the accommodating cavity. Since the wall thickness of the side wall in the thickened area is relatively large, the battery cell cover plate and the battery cell shell have sufficient weld width after welding, thereby improving the welding strength of the battery cell shell and the battery cell cover plate, and at the same time will not excessively increase the weight of the battery cell; the pole group is assembled in the main body area, and the wall thickness of the side wall in the main body area is relatively small and thus will not occupy the space inside the battery cell, thereby avoiding the situation where the battery cell capacity is reduced due to increased wall thickness.

[0050] A battery cell provided by the present invention includes a battery cell shell as described above, and the battery cell shell is formed into a shell structure with unequal wall thicknesses. Since the wall thickness of the side wall in the thickened area is relatively large, it is ensured that the battery cell cover plate and the battery cell shell have a sufficient weld width after welding, thereby improving the welding strength of the battery cell shell and the battery cell cover plate, thereby improving the production yield of the battery cell, and at the same time improving the manufacturing processability of the battery cell without excessively increasing the weight of the battery cell. The wall thickness of the side wall in the main body area is relatively small and thus does not occupy the space inside the battery cell, thereby avoiding the situation where the battery cell capacity is reduced due to increased wall thickness, thereby meeting the user's demand for battery cell capacity.

[0051] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; 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 be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A battery cell casing, characterized in that: An accommodating cavity is formed inside the battery cell housing, and a side wall of the battery cell housing includes a thickened area and a body area arranged along the depth direction of the accommodating cavity, the thickened area protrudes inwardly on a side facing the accommodating cavity, so that the thickness of the side wall of the thickened area is greater than the thickness of the side wall of the body area, and the thickened area is arranged at the opening of the accommodating cavity; The thickness dimension of the side wall of the body region is t, 0.35 mm ≤ t ≤ 0.65 mm; The thickness dimension of the side wall of the thickened area is t1, 1.1≤t1 / t≤1.

7.

2. The battery cell casing according to claim 1, characterized in that: The dimension of the thickened area in the depth direction of the accommodating cavity is h1, 1mm≤h1≤2mm.

3. The battery cell casing according to claim 1, characterized in that: The side wall of the battery cell housing along the depth direction of the accommodating cavity further includes a transition zone arranged between the thickened area and the body area, and the transition zone forms a transition portion on a side facing the accommodating cavity.

4. The battery cell casing according to claim 3, characterized in that: The transition portion is arranged to be inclined, and an angle between the transition portion and the depth direction of the accommodating cavity is θ, 10°≤θ≤30°.

5. The battery cell casing according to claim 3, characterized in that: The total dimension of the transition zone and the thickened zone in the depth direction of the accommodating cavity is h2, 3.5 mm≤h2≤5.5 mm.

6. The battery cell casing according to claim 3, characterized in that: A side of the side wall of the thickened area facing the accommodating cavity is formed as a first cavity wall, a first fillet is provided between the transition portion and the first cavity wall, and the radius of the first fillet is R1, 1mm≤R1≤5mm; And / or, a side of the side wall of the main body region facing the accommodating cavity is formed as a second cavity wall, a second fillet is provided between the transition portion and the second cavity wall, and the radius of the second fillet is R2, 1mm≤R2≤5mm.

7. The battery cell casing according to claim 1, characterized in that: The battery cell housing includes a first side wall and a second side wall, the area of ​​the first side wall is greater than the area of ​​the second side wall, and the thickened area is arranged on the first side wall.

8. A battery cell, characterized in that: A battery cell casing comprising any one of claims 1 to 7.

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