Battery case, battery, and battery pack

Abstract

The application provides a battery shell, a battery and a battery pack. The battery shell comprises a bottom shell defining a receiving cavity with an opening at one end, the bottom shell comprising a side plate surrounding the receiving cavity, the side plate comprising a main body part and a connecting part, the outer wall surface of the connecting part being recessed inwardly relative to the outer wall surface of the main body part; and a top cover covering the opening and welded with the outer wall surface of the connecting part. The battery of the application is beneficial to making the welding seam not outwardly convex relative to the outer wall surface of the main body part, and beneficial to making the outer wall surfaces of the main body parts of adjacent batteries tightly abut each other when a plurality of batteries form a module, so that the corresponding module structure is compact, and relative movement between the batteries is avoided, so that the batteries in the corresponding module are prevented from being damaged due to collision.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery casing, a battery, and a battery pack. Background Technology

[0002] With the development of science and technology, batteries are widely used in new energy vehicles, electric transportation, and energy storage. A battery consists of a battery casing and battery cells assembled within the casing. The battery casing includes a bottom shell and a top cover, with the top cover fixed to the bottom shell by welding.

[0003] In related technologies, the weld between the bottom shell and the top cover tends to protrude from the outer surface of the battery casing. When multiple batteries are assembled into a module, the protruding weld is not conducive to the close arrangement of the batteries. Utility Model Content

[0004] This application provides a battery casing, a battery, and a battery pack to solve the problem that the weld protrusion between the bottom shell and the top cover is not conducive to the close arrangement of batteries when multiple batteries are formed into a module.

[0005] The battery casing of this application includes: a bottom shell defining a receiving cavity with an opening at one end, the bottom shell including a side plate surrounding the receiving cavity, the side plate including a main body and a connecting portion, the outer wall surface of the connecting portion being recessed into the outer wall surface of the main body; and a top cover sealing the opening and welded to the outer wall surface of the connecting portion.

[0006] In some embodiments, the thickness of the main body and the connecting portion is uniform along the opening direction of the bottom shell.

[0007] In some embodiments, the inner wall surface of the connecting portion protrudes inward from the inner wall surface of the main body portion.

[0008] In some embodiments, the side plate further includes a transition portion located between the main body portion and the connecting portion, wherein the side surface of the top cover facing the interior of the receiving cavity does not exceed the junction of the connecting portion and the transition portion.

[0009] In some embodiments, along the opening direction of the bottom shell and from the main body toward the connecting portion, the transition portion includes a first transition segment and a second transition segment connected in sequence; wherein, the outer wall surface of the first transition segment is flush with the outer wall surface of the main body, and the inner wall surface of the first transition segment extends inwardly from the main body toward the second transition segment; the inner wall surface of the second transition segment is flush with the inner wall surface of the connecting portion, and the outer wall surface of the second transition segment extends inwardly from the first transition segment toward the connecting portion.

[0010] In some embodiments, the thickness L1 at the connection between the first transition segment and the second transition segment and the thickness L2 of the main body satisfy the following condition: 1.25≤L1 / L2≤1.5.

[0011] In some embodiments, the thickness L1 at the connection between the first transition segment and the second transition segment and the thickness L3 of the connection portion satisfy: 0.05mm≤L1-L3≤0.15mm.

[0012] In some embodiments, the top cover includes: a top cover body, at least a portion of which is located inside the connecting portion; and a connecting boss, which protrudes from the outer periphery of the top cover body and is located at one end of the top cover body facing away from the cavity, wherein the connecting boss is stacked and welded to the connecting portion.

[0013] In some embodiments, the outer wall surface of the connecting boss is flush with the outer wall surface of the connecting portion.

[0014] In some embodiments, the battery housing further includes a plastic component for separating the top cover and the battery cell, the plastic component being opposite to and spaced apart from the transition portion, along the opening direction of the bottom shell and from the outside of the receiving cavity toward the inside of the receiving cavity, wherein one end of the transition portion toward the main body portion does not exceed the side surface of the plastic component toward the inside of the receiving cavity.

[0015] The battery provided in this application includes: the battery casing as described above; and a battery cell disposed within the receiving cavity of the battery casing.

[0016] The battery pack provided in this application includes a plurality of batteries as described above, with the side plates of adjacent batteries abutting each other.

[0017] The battery casing, battery, and battery pack of this application feature a connecting portion on the side plate of the bottom casing. The outer wall surface of the connecting portion is recessed into the outer wall surface of the main body, and the top cover is welded to the outer wall surface of the connecting portion. This design places the weld seam connecting the top cover and the bottom casing on the outer wall surface of the connecting portion, ensuring the weld seam does not protrude outwards relative to the outer wall surface of the main body. This allows for tight contact between the outer walls of the main bodies of adjacent batteries when multiple batteries are assembled into a module. It solves the problem of the protruding weld seam between the bottom casing and the top cover hindering the close arrangement of batteries and also helps prevent relative movement between batteries, thus avoiding collision damage to batteries within the corresponding module and protecting the batteries. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0019] Figure 1 A schematic diagram of the battery casing provided in the application embodiment;

[0020] Figure 2 for Figure 1 A schematic diagram of the AA cross-section;

[0021] Figure 3 for Figure 2 An enlarged view of part B in the image;

[0022] Figure 4 This is a schematic diagram of the bottom shell provided in an embodiment of this application;

[0023] Figure 5 for Figure 4 A schematic diagram of the CC cross-section;

[0024] Figure 6 for Figure 5 An enlarged view of part D in the image.

[0025] Explanation of reference numerals in the attached figures:

[0026] 100-Bottom shell; 100a-Opening; 100b-Receiving cavity; 110-Side plate; 111-Main body; 112-Connecting part; 113-Transition part; 113a-First transition section; 113b-Second transition section;

[0027] 200 - Top cover; 210 - Top cover body; 220 - Connecting boss;

[0028] 300 - Plastic parts;

[0029] 400 - Weld.

[0030] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0031] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0032] With the development of science and technology, batteries are widely used in new energy vehicles, electric transportation, and energy storage. A battery consists of a battery casing and battery cells assembled within the casing. The battery casing includes a bottom shell and a top cover, with the top cover fixed to the bottom shell by welding.

[0033] For example, the bottom shell and top cover are usually made of aluminum alloy. During the welding process of aluminum alloy, it is usually necessary to use a protective gas (such as helium) to protect the welding position to prevent the molten metal from reacting with oxygen and nitrogen in the air, thereby obtaining a high-quality, defect-free weld.

[0034] In related technologies, the weld between the bottom shell and the top cover tends to protrude from the outer surface of the battery casing, which is not conducive to the close arrangement of multiple batteries.

[0035] For example, when a battery pack is made up of multiple batteries, the batteries may not be arranged closely together, which may cause the battery pack to exceed the size limit or reduce the number of batteries that the battery pack can carry.

[0036] For example, in new energy vehicles, the inability to arrange batteries closely together can easily lead to collisions and damage to the batteries due to relative movement.

[0037] To address the problem of the weld seam protrusion between the bottom shell and top cover hindering the close arrangement of batteries, this application provides a battery housing, a battery, and a battery pack. The battery housing features a connecting portion on the side plate of the bottom shell, with the outer wall of the connecting portion recessed into the outer wall of the main body. The top cover is welded to the outer wall of the connecting portion, so that the weld seam connecting the top cover and bottom shell is located on the outer wall of the connecting portion, preventing the weld seam from protruding outwards relative to the outer wall of the main body. This allows for close contact between the outer walls of adjacent battery bodies when multiple batteries are assembled into a module, solving the problem of the weld seam protrusion between the bottom shell and top cover hindering the close arrangement of batteries. It also helps prevent relative movement between batteries, avoiding collision damage to batteries in the corresponding module and providing battery protection.

[0038] Reference Figures 1 to 4 As shown, the battery casing of this embodiment includes a bottom shell 100 and a top cover 200. Exemplarily, both the bottom shell 100 and the top cover 200 are made of aluminum alloy, which is understood to have advantages such as lightweight and corrosion resistance. Alternatively, both the bottom shell 100 and the top cover 200 can be made of steel, especially high-strength steel. It is understood that compared to aluminum alloy, steel has the advantage of high strength, resulting in a battery casing with strong impact and compression resistance. It should be noted that when the bottom shell 100 and the top cover 200 are made of steel, their surfaces can be treated with rust prevention methods such as electroplating or spraying.

[0039] The bottom shell 100 defines a receiving cavity 100b with an opening 100a at one end. The receiving cavity 100b is used to accommodate the battery cell and related components such as insulation and sealing components. The bottom shell 100 includes a side plate 110 surrounding the receiving cavity 100b. The side plate 110 is cuboid with rounded corners. The side plate 110 includes a main body 111 and a connecting part 112. The outer wall surface of the connecting part 112 is recessed into the outer wall surface of the main body 111. A top cover 200 covers the opening 100a and is welded to the outer wall surface of the connecting part 112.

[0040] Reference Figures 1 to 4 As shown, the battery casing of this application, by providing a connecting portion 112 on the side plate 110 of the bottom shell 100, with the outer wall surface of the connecting portion 112 recessed into the outer wall surface of the main body 111, and by welding the top cover 200 to the outer wall surface of the connecting portion 112, a weld 400 for connecting the top cover 200 and the bottom shell 100 is provided on the outer wall surface of the connecting portion 112, so that the weld 400 does not protrude outward relative to the outer wall surface of the main body 111. Thus, when multiple batteries form a module, it facilitates a tight abutment between the outer walls of the main bodies 111 of adjacent batteries, solving the problem that the protruding weld 400 between the bottom shell 100 and the top cover 200 is not conducive to the tight arrangement of batteries; it also helps to prevent relative movement between batteries, thereby avoiding collision damage to batteries in the corresponding module and protecting the batteries.

[0041] Reference Figures 2 to 6 As shown, in some embodiments, the thickness of the main body 111 is uniform along the direction of the opening 100a of the bottom shell 100. It should be noted that when multiple batteries are assembled, there is mutual compressive force between adjacent battery casings. The uniform thickness of the main body 111 facilitates a more even distribution of the load generated by this compression. The thickness of the connecting portion 112 is also uniform. This reduces welding difficulty. It is understood that a portion of the weld 400 is located on the top cover 200, and another portion is located on the connecting portion 112. The uniform thickness of the connecting portion 112 makes it easier to set welding parameters compared to non-uniform features during welding operations. It also helps to avoid welding defects such as burn-through or lack of fusion, ensures consistent quality throughout the weld 400, and reduces residual stress and deformation.

[0042] Reference Figure 3 and Figure 6As shown, in some embodiments, the inner wall surface of the connecting portion 112 protrudes inward from the inner wall surface of the main body portion 111. This facilitates thickening of the inner wall surface of the connecting portion 112, preventing the connecting portion 112 from being burned through during welding. It also helps ensure the strength of the connecting portion 112. For example, the amount by which the connecting portion 112 protrudes relative to the inner wall surface of the main body portion 111 is sufficient not to affect the assembly of the top cover 200 or related components assembled inside the battery case.

[0043] Reference Figures 1 to 6 As shown, in some embodiments, the side plate 110 further includes a transition portion 113. The transition portion 113 is located between the main body portion 111 and the connecting portion 112. The side surface of the top cover 200 facing the interior of the receiving cavity 100b does not extend beyond the junction of the connecting portion 112 and the transition portion 113. Thus, the entire circumferential outer wall of the top cover 200 facing the interior of the receiving cavity 100b is opposite to the inner wall of the connecting portion 112, so that the size of the gap in the opposite area is relatively uniform, thereby reducing the impact of minor deformation of the connecting portion 112 or the main body portion 111 that may be caused by welding.

[0044] Reference Figures 2 to 6 As shown, in some embodiments, along the direction of the opening 100a of the bottom shell 100 and from the main body 111 toward the connecting part 112, the transition part 113 includes a first transition section 113a and a second transition section 113b connected in sequence. The outer wall surface of the first transition section 113a is flush with the outer wall surface of the main body 111, and the inner wall surface of the first transition section 113a extends inwardly from the main body 111 toward the second transition section 113b. Thus, by gradually thickening the inner side of the side plate 110 through the first transition section 113a, stress is dispersed; it also helps maintain the smoothness of the inner wall surface of the side plate 110, preventing scratches on the components being inserted or removed during battery assembly when inserting or removing components into the receiving cavity 100b.

[0045] The inner wall surface of the second transition section 113b is flush with the inner wall surface of the connecting portion 112, which facilitates the smoothness between the inner wall surfaces of the second transition section 113b and the connecting portion 112. The outer wall surface of the second transition section 113b extends inwardly from the first transition section 113a toward the connecting portion 112, which facilitates the gradual thickening of the outer wall of the side plate 110, reduces stress, maintains the smoothness of the outer wall of the side plate 110, and prevents the outer wall of the side plate 110 from scratching surrounding equipment.

[0046] In some embodiments, the thickness L1 at the connection between the first transition section 113a and the second transition section 113b satisfies the following condition: 1.25 ≤ L1 / L2 ≤ 1.5. For example, the value of L1 / L2 can be 1.25, 1.3, 1.35, 1.4, 1.45, or 1.5; however, this application does not impose any limitations on this, and the value of L1 / L2 can be reasonably selected within the above range. The above range of L1 / L2 ensures that the thickness of the transition section 113 and the connecting section 112 is sufficient to guarantee their strength and prevent weld burn-through. It also avoids the problem of reduced weld quality due to excessive thickness, and eliminates the need for beveling during welding. If L1 / L2 is less than 1.25 (too small), the thickness of the transition section 113 and the connecting section 112 is easily too small, resulting in insufficient strength and potential burn-through during welding. If L1 / L2 is greater than 1.5, it is too large. If L1 / L2 is too large, the opening 100a will be too small. On the one hand, this will affect the insertion and assembly of the components inside the battery casing. On the other hand, it will easily cause the battery to be too heavy.

[0047] Reference Figure 6 As shown, in some embodiments, the thickness L1 at the connection between the first transition section 113a and the second transition section 113b satisfies the following condition: 0.05mm ≤ L1 - L3 ≤ 0.15mm. It can be understood that L1-L3 is the concave value of the outer wall surface of the connecting portion 112 relative to the outer wall surface of the main body portion 111. For example, the values ​​of L1-L3 can be 0.05mm, 0.07mm, 0.09mm, 0.1mm, 0.12mm, 0.14mm, or 0.15mm. Of course, this application does not limit this, and the values ​​of L1-L3 can be reasonably selected within the above range according to requirements. It should be noted that during welding, the maximum height of the molten pool protrusion is 0.1mm, and after the molten pool solidifies, it becomes weld 400, meaning the maximum height of weld 400 is 0.1mm. This application sets L1-L3 to 0.5mm to 0.15mm, which can meet the requirement that the weld 400 does not protrude beyond the outer wall surface of the main body 111.

[0048] For example, when the protrusion height of weld 400 is 0.04 mm, L1-L3 can be 0.005 mm, meaning the concavity of the outer wall surface of the connecting portion 112 relative to the outer wall surface of the main body 111 is 0.005 mm. This concavity is sufficient to prevent the weld with a height of 0.04 mm from protruding beyond the outer wall surface of the main body 111. It is understandable that the values ​​of L1-L3 can be flexibly selected and set according to the protrusion height of the weld, wherein the values ​​of L1-L3 are not less than the protrusion height of weld 400.

[0049] If the value of L1-L3 is less than 0.05mm, then L1-L3 is too small. On the one hand, the processing is more difficult, and on the other hand, the control of the weld during the welding process is more difficult. The amount of the weld 400 protrusion needs to be reduced accordingly to avoid the weld 400 protruding from the outer wall surface of the main body 111, which will easily result in weaker welding strength.

[0050] If the value of L1-L3 is greater than 0.15mm, then L1-L3 is too large, which means that the concave value of the connecting part 112 is too large. On the one hand, it exceeds the required value and causes excessive redundancy; on the other hand, it is easy to increase the stress on the outer wall surface of the connecting part 112 during the welding process.

[0051] Reference Figure 2 and Figure 3 As shown, in some embodiments, the top cover 200 includes a top cover body 210 and a connecting boss 220. At least a portion of the structure of the top cover body 210 is located inside the connecting portion 112. The connecting boss 220 protrudes from the outer periphery of the top cover body 200 and is located at one end of the top cover body 200 facing away from the interior of the receiving cavity 100b. The connecting boss 220 and the connecting portion 112 are stacked and welded together. Thus, by forming a sleeve between the portion of the top cover body 210 located inside the connecting portion 112 and the connecting portion 112, and by stacking the connecting boss 220 and the connecting portion 112, it is beneficial to reduce the stress borne by the weld and to improve the weld life. It should be noted that during the welding process, high temperature causes the adjacent portions of the connecting portion 112 and the top cover body 210 to melt, forming a molten pool that penetrates into the stacked position. After the molten pool solidifies, a weld that penetrates into the stacked position can be formed at the stacked position.

[0052] Reference Figure 3 As shown, the outer wall surface of the connecting boss 220 is flush with the outer wall surface of the connecting portion 112. This avoids airflow disturbance caused by uneven surfaces during welding, allowing the protective gas to flow smoothly and evenly at adjacent positions on the outer wall surfaces of the connecting boss 220 and the connecting portion 112. This improves the uniformity of the protective gas distribution at these locations, resulting in a uniform protective gas layer and ultimately ensuring weld quality.

[0053] Reference Figure 2 and Figure 3As shown, in some embodiments, the battery housing also includes a plastic component 300. The plastic component 300 serves to separate the top cover 200 and the battery cells. The plastic component 300 is positioned opposite and spaced apart from the transition portion 113. Along the direction of the opening 100a of the bottom shell 100 and from the outside of the receiving cavity 100b toward the inside of the receiving cavity 100b, the end of the transition portion 113 facing the main body portion 111 does not exceed the side surface of the plastic component 300 facing the inside of the receiving cavity 100b. This avoids the inwardly thickened portion of the side plate 110 from affecting the installation of the plastic component 300 or from causing compression damage to the plastic component 300.

[0054] In some embodiments, the total dimension of the transition portion 113 and the connecting portion 112 along the direction of the opening 100a of the bottom shell 100 is defined as h1, and the dimension of the connecting portion 112 is h2, where h2 ≤ 0.5h1. For example, h2 = 0.5h1, 0.45h1, 0.4h1, or 0.35h1. This is beneficial for both welding effect and welding strength, and does not affect the expansion of the JR inside the opening 100a. It should be noted that JR expansion refers to the phenomenon of local volume increase in the welded joint (especially the heat-affected zone) due to the precipitation of carbides (mainly chromium carbides, such as Cr23C6) under the action of welding thermal cycling.

[0055] For example, the feature of the bottom shell 100 located near the opening 100a can be formed by stretching and shaping a mold.

[0056] Reference Figures 1 to 6 As shown, the battery provided in the embodiment of this application is a square battery, which includes the aforementioned battery casing and battery cell. The battery cell is disposed within the receiving cavity 100b of the battery casing. Exemplarily, insulating materials such as insulating partitions can be provided between the battery cell and the bottom casing 100, and between the battery cell and the top cover 200. The battery includes terminals (including positive and negative terminals). The top cover 200 has holes for passing through the corresponding terminals, so that the corresponding terminals pass through the top cover 200, and the terminals and the battery cell are electrically connected. An insulating material is provided between the terminals and the top cover 200 to prevent short circuits between terminals of different polarities due to the top cover 200.

[0057] For example, the battery cell has tabs of corresponding polarity, namely a positive tab and a negative tab. The positive tab is electrically connected to the positive terminal, and the negative tab is electrically connected to the negative terminal. The tabs and their corresponding terminals can be connected via an intermediate conductive connector.

[0058] The battery provided in this application, by setting the battery casing of this application, helps to ensure that the weld between its bottom shell 100 and top cover 200 does not protrude outward from the outer wall surface of the main body 111, so as to facilitate the close arrangement and assembly of multiple batteries.

[0059] For example, the battery provided in this application can be applied to a prefabricated compartment, which is provided with a battery rack for placing the batteries. When the batteries provided in this application are placed on the battery rack, they can be arranged closely together, thereby increasing the battery density on the battery rack.

[0060] The battery pack provided in this application includes multiple batteries as described above, with the side plates 110 of adjacent batteries abutting each other. By arranging the batteries in this application, the battery pack improves the compactness of the battery arrangement, allowing for a larger number of batteries while maintaining a fixed battery pack volume. Conversely, it reduces the overall size of the battery pack while maintaining a fixed number of batteries. Furthermore, it prevents relative movement between batteries, thus avoiding collision damage and protecting the battery pack.

[0061] For example, in a battery pack, multiple batteries arranged together can be secured by applying pressure from the outside using structural components such as end plates, side plates, cable ties, or frames; alternatively, the battery pack has a housing with connecting frames or receiving cavities for securing or restraining the batteries, with multiple batteries disposed on corresponding connecting frames or receiving cavities to be secured by compression from the walls of the connecting frames or receiving cavities. The housing serves for safety protection.

[0062] In a battery pack, the electrodes of the batteries are connected via connectors. These connections can be flexibly selected according to requirements, and can be parallel, series, or a combination of both. The battery pack may also include a battery management system, a cooling system, and a sealing system.

[0063] For example, the functions of a battery management system may include real-time estimation of state of charge, state of health, and state of power; and providing early warning and protection against faults such as overvoltage, undervoltage, overcurrent, short circuit, and high temperature. This application does not limit the specific functions and structure of the battery management system, and can flexibly select and set them according to specific needs.

[0064] Understandably, the cooling system is used to dissipate heat from the battery pack. The cooling system can be either air-cooled or liquid-cooled; however, this application does not impose any restrictions and allows for flexible selection based on specific needs.

[0065] For example, the sealing system may employ sealant, sealing rings, etc., to ensure that the battery pack achieves an IP67 or higher protection rating, preventing dust intrusion and short-term water immersion. This application does not limit the specific sealing mechanism; it can be flexibly selected and configured according to requirements.

[0066] Finally, it should be noted that other embodiments of this utility model will readily conceive of by those skilled in the art upon consideration of the specification and practice of the utility model disclosed herein. This utility model is intended to cover any variations, uses, or adaptations of this utility model that follow the general principles of this utility model and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this utility model is limited only by the appended claims.

Claims

1. A battery casing, characterized in that, include: A bottom shell (100) defines a receiving cavity (100b) having an opening (100a) at one end. The bottom shell (100) includes a side plate (110) surrounding the receiving cavity (100b). The side plate (110) includes a main body (111) and a connecting part (112). The outer wall surface of the connecting part (112) is recessed into the outer wall surface of the main body (111). A top cover (200) is provided to cover the opening (100a) and is welded to the outer wall of the connecting part (112).

2. The battery casing according to claim 1, characterized in that, Along the direction of the opening (100a) of the bottom shell (100), the thickness of the main body (111) and the connecting part (112) is uniform.

3. The battery casing according to claim 2, characterized in that, The inner wall surface of the connecting part (112) protrudes inward from the inner wall surface of the main body part (111).

4. The battery casing according to claim 3, characterized in that, The side plate (110) also includes: The transition portion (113) is located between the main body portion (111) and the connecting portion (112), and the side surface of the top cover (200) facing the interior of the receiving cavity (100b) does not exceed the junction of the connecting portion (112) and the transition portion (113).

5. The battery casing according to claim 4, characterized in that, Along the direction of the opening (100a) of the bottom shell (100) and from the main body (111) toward the connecting part (112), the transition part (113) includes a first transition section (113a) and a second transition section (113b) connected in sequence. Wherein, the outer wall surface of the first transition section (113a) is flush with the outer wall surface of the main body (111), and the inner wall surface of the first transition section (113a) extends inward from the main body (111) toward the second transition section (113b); The inner wall surface of the second transition section (113b) is flush with the inner wall surface of the connecting part (112), and the outer wall surface of the second transition section (113b) extends inward from the first transition section (113a) toward the connecting part (112).

6. The battery casing according to claim 5, characterized in that, The thickness L1 at the connection between the first transition section (113a) and the second transition section (113b) satisfies the following condition with respect to the thickness L2 of the main body (111): 1.25 ≤ L1 / L2 ≤ 1.

5.

7. The battery casing according to claim 5, characterized in that, The thickness L1 at the connection between the first transition section (113a) and the second transition section (113b) satisfies the following condition: 0.05mm≤L1-L3≤0.15mm.

8. The battery casing according to claim 5, characterized in that, The top cover (200) includes: Top cover body (210), at least a portion of the structure of the top cover body (210) is located inside the connecting portion (112); A connecting boss (220) is provided on the outer periphery of the main body of the top cover (200) and located at one end of the main body of the top cover (200) facing away from the interior of the receiving cavity (100b). The connecting boss (220) and the connecting part (112) are stacked and welded together.

9. The battery casing according to claim 8, characterized in that, The outer wall surface of the connecting boss (220) is flush with the outer wall surface of the connecting part (112).

10. The battery casing according to claim 4, characterized in that, Also includes: A plastic part (300) is used to separate the top cover (200) and the battery cell. The plastic part (300) is opposite to and spaced apart from the transition portion (113). The transition portion (113) is positioned along the opening (100a) of the bottom shell (100) and from the outside of the receiving cavity (100b) toward the inside of the receiving cavity (100b). The end of the transition portion (113) facing the main body portion (111) does not exceed the side surface of the plastic part (300) facing the inside of the receiving cavity (100b).

11. A battery, characterized in that, include: Battery casing as claimed in any one of claims 1-10; The battery cell is disposed within the receiving cavity (100b) of the battery casing.

12. A battery pack, characterized in that, The battery includes multiple batteries as described in claim 11, with the side plates (110) of adjacent batteries abutting each other.

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