Housing and battery cell

Abstract

The application provides a shell and a battery monomer, the projection of the shell in the height direction is a polygon, the polygon comprises a corner arranged between two adjacent edges, the shell is provided with a main body area at least at the corner, and the shell is further provided with at least one thinning area located between two adjacent corners; the thickness of the thinning area is less than the thickness of the main body area. The shell and the battery monomer provided by the application help to improve the sealing performance and safety performance of the shell.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a casing and a battery cell. Background Technology

[0002] In the development of battery technology, besides improving the performance of individual battery cells, safety is also a crucial issue that cannot be ignored. If the safety of individual battery cells cannot be guaranteed, then those cells cannot be used. Therefore, how to enhance the safety of individual battery cells is a pressing technical problem that needs to be solved in battery technology. Utility Model Content

[0003] In view of this, the purpose of this application is to provide a casing and a battery cell to at least partially solve the problem of how to enhance the safety of the battery cell.

[0004] To achieve the above objectives, the first aspect of this application provides a housing, wherein the projection of the housing along the height direction is a polygon, the polygon includes a corner disposed between two adjacent edges, the housing has a main body area disposed at least at the corner, and the housing is further provided with at least one thinning area located between two adjacent corners; the thickness of the thinning area is less than the thickness of the main body area.

[0005] Optionally, the outer casing includes a shell and a cover plate body. The shell has an open end, and the cover plate body is connected to the open end and surrounds the shell to form an accommodating space. The cover plate body has an electrode post, and the thinning area is disposed on the surface of the cover plate body facing the accommodating space and is located between the edge of the cover plate body and the electrode post.

[0006] Optionally, the cover plate body includes two first edges spaced apart along the length direction, and the thinning area extends from the first edges toward the pole.

[0007] Optionally, along the width direction of the cover plate body, the main body area is provided on both opposite sides of the thinning area, and the size of the cover plate body is W1, the size of the thinning area is W2, and the ratio of W2 to W1 is 0.3 to 0.7; and / or, Along the length of the cover plate body, the minimum straight-line distance between the first edge and the pole post is L1, the extension length of the thinning region is L2, and the ratio of L2 to L1 is 0.25 to 0.6; and / or, The thickness of the thinned region is H2, the thickness of the main region is H1, and the ratio of H2 to H1 is 0.5 to 0.7; and / or, The thickness of the thinning zone is H2. The cover plate body is welded to the shell and a welded portion is formed on the cover plate body. The welded portion extends from the surface of the cover plate body away from the receiving space to the receiving space, and the extension dimension is H3, where H2 > 1.2H3.

[0008] Optionally, the outer casing includes a shell and a cover plate body. The shell includes a bottom plate and multiple side plates, which together form a cylindrical structure. One end of the cylindrical structure is configured as an open end, and the other end is connected to the bottom plate. The cover plate body is connected to the open end and together with the shell to form an accommodating space. The thinning area is disposed on the surface of the side plate facing the accommodating space.

[0009] Optionally, the side plate is provided with an assembly area for cooperating with the cover plate body along the edge near the opening end. The thickness of the assembly area is not less than the thickness of the thinning area, and the thickness of the assembly area is less than the thickness of the main body area. The projections of the thinning area and the assembly area along the thickness direction of the side plate do not overlap.

[0010] Optionally, a bottom transition portion is formed between the side plate and the bottom plate on the side facing the receiving space, the thinning area extends from the assembly area to the bottom plate, and the projections of the thinning area and the bottom transition portion along the thickness direction of the side plate do not overlap.

[0011] Optionally, the side plate includes two first side plates arranged opposite each other along the length direction of the cover plate body, and the thinning area is disposed on the first side plate; Along the width direction of the cover plate body, the main body area is provided on both opposite sides of the thinning area, and the size of the first side plate is W3, the size of the thinning area is W4, and the ratio of W4 to W3 is 0.3 to 0.7; and / or, The thickness of the thinning region is H4, and the thickness of the main region is H5, with the ratio of H4 to H5 being 0.7 to 0.8.

[0012] Optionally, a transition zone is provided between the thinning zone and the main body zone, and the thickness of the transition zone gradually increases from the thinning zone to the main body zone.

[0013] Based on the same inventive concept, the second aspect of this application also provides a battery cell, including the casing as described in the first aspect.

[0014] As can be seen from the above, the casing and battery cell provided in this application, by setting a thinner area on the casing, allow the thinner area to locally deform and release part of the impact force when the electrode assembly within the housing impacts the casing due to its weaker structural strength. This reduces the total amount of impact force transmitted to other areas of the casing, thereby lowering the risk of cracking at the welded joints on the casing due to impact. Simultaneously, the presence of a thicker main body area at least at the corners ensures that the corners of the casing will not deform or crack when impacted, contributing to improved sealing and safety performance of the casing.

[0015] In addition, by setting a thinner zone, the weight of the casing can be reduced, which helps to improve the energy density of the battery cells. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a partial cross-sectional view of the outer shell of the first structure according to an embodiment of this application; Figure 2 This is a top view of the second structure of the outer shell in this application embodiment when the cover plate body and the shell are not welded together; Figure 3 for Figure 2 Partial cross-sectional diagram of section AA; Figure 4 for Figure 3 An enlarged schematic diagram of section C; Figure 4a In this embodiment of the application, the cover plate body is welded to the shell after... Figure 3 An enlarged schematic diagram of section C; Figure 5 for Figure 2 Partial cross-sectional diagram of section BB; Figure 6 The outer shell of the third structure in the embodiments of this application is in Figure 2 Partial cross-sectional diagram of section AA; Figure 7 for Figure 6 An enlarged schematic diagram of section E in the middle; Figure 8 for Figure 7 Partial cross-sectional diagram of the GG section; Figure 9for Figure 7 Partial cross-sectional view of the FF section; Figure 10 for Figure 6 An enlarged schematic diagram of part D in the middle.

[0018] Explanation of reference numerals in the attached figures: 100. Cover plate assembly; 110. Cover plate body; 120. Pole post; 200, Shell; 210, Side plate; 211, First side plate; 212, Second side plate; 220, Bottom plate; 230, Bottom transition section; 240, Open end; 300, Accommodation space; 400, Welded section; 500, Substrate; 510, Inner plate surface; 511, Thinning area; 512, Main body area; 513, Transition area; 514, Assembly area; 515, Top transition area; 516, First edge; 517, Second edge; 600. Electrode assembly. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0020] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components described in these embodiments do not limit the scope of this application.

[0021] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0022] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0023] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Figure 1 A partial cross-sectional schematic diagram of the outer shell of the first structure is shown.

[0025] like Figure 1 In some embodiments, the housing includes a housing 200 and a cover assembly 100. The housing 200 may include a base plate 220, each of the four edges of which is connected to a side plate 210. The cover assembly 100 is connected to the end of the side plate 210 away from the base plate 220, so that the housing 200 and the cover assembly 100 together form a receiving space 300 for accommodating the electrode assembly 600 (or, bare cell). The cover assembly 100 includes a cover body 110 welded to the housing 200 and an electrode post 120 (or, electrode lead-out end) disposed on the cover body 110. The cover body 110 may include a flat plate structure, and a welded portion 400 is formed at the welded position between the cover body 110 and the housing 200. One end of the electrode post 120 is located within the receiving space 300 and electrically connected to the tab of the electrode assembly 600, and the other end of the electrode post 120 extends out of the cover body 110 and is used for electrical connection to an external circuit (e.g., a busbar assembly or a battery).

[0026] The applicant's research found that, in order to improve the energy storage capacity of individual battery cells, the size and weight of the electrode assembly 600 are constantly increasing with technological advancements. During vibration testing of individual battery cells, the impact of the electrode assembly 600 on the outer casing can easily lead to fatigue failure at the weld joint 400 between the cover plate body 110 and the housing 200, resulting in cracking of the weld joint 400. This can adversely affect the sealing and safety performance of the individual battery cells.

[0027] Due to the limitations of the processing technology of the shell 200, it is difficult to form a side plate 210 with a large thickness. Therefore, it is difficult to prevent the welded part 400 from cracking by increasing the thickness of the side plate 210 and the weld width of the welded part 400.

[0028] Furthermore, after numerous experiments, it has been found that increasing the weld depth of the weld 400 is not a significant way to reduce the risk of cracking in the weld 400.

[0029] To address the aforementioned issues, this embodiment provides housings with alternative structures.

[0030] Figure 2 This diagram shows a top view of the second type of housing before the cover plate body 110 and the housing 200 are welded together. Figure 3 Showing Figure 2 Partial cross-sectional diagram of section AA. Figure 4 Showing Figure 3 An enlarged diagram of section C. Figure 4a This demonstrates the welding of the cover plate body 110 and the housing 200. Figure 3 An enlarged schematic diagram of section C.

[0031] like Figure 2 , Figure 3 , Figure 4 and Figure 4a In some embodiments, the housing is along the height direction (e.g.) Figure 3 The projection of the Z direction in the shell is a polygon, the polygon includes a corner 500 between two adjacent edges, the shell has a main body area 700 at least at the corner 500, and the shell also has at least one thinning area 800, the thinning area 800 is located between two adjacent corners 500; the thickness of the thinning area 800 is less than the thickness of the main body area 700.

[0032] For example, the polygon can be a right-angled rectangle or a rounded rectangle.

[0033] For example, a stepped surface may be formed between the thinning region 800 and the main body region 700; or, the thinning region 800 and the main body region 700 may be smoothly transitioned by a slope or an arc surface.

[0034] For example, the thinning zone 800 can be formed by stamping or other methods.

[0035] In this embodiment, because the thickness of the thinning region 800 is relatively small, the structural strength of the thinning region 800 is relatively weak. When the electrode assembly 600 within the accommodating space 300 impacts the shell, the thinning region 800, with its weaker structural strength, will undergo local deformation to release some of the impact force. For example... Figure 4a Therefore, the impact force ultimately transmitted to the welded portion 400 on the outer shell will be reduced accordingly, and the risk of the welded portion 400 cracking under the influence of the impact force will also be reduced.

[0036] However, it is understandable that if the corner 500 of the outer casing deforms, it may crack, which would adversely affect the sealing performance of the outer casing. To avoid the above problems, this embodiment provides at least a thicker main body area 700 at the corner 500. The main body area 700 has relatively strong structural strength and is not easily deformed when the outer casing is subjected to impact, which helps to ensure the sealing performance of the outer casing.

[0037] The housing provided in this embodiment, by providing a thinned area 800 with a smaller thickness, allows the thinned area 800 to locally deform and release part of the impact force when the electrode assembly 600 within the accommodating space 300 impacts the housing. This reduces the total amount of impact force transmitted to other areas of the housing, thereby lowering the risk of cracking of the welded joint 400 due to impact. Simultaneously, a thicker main body area 700 is provided at least at the corner 500 to ensure that the corner 500 of the housing does not deform or crack when impacted, contributing to improved sealing and safety performance of the housing.

[0038] Furthermore, by setting a thinning zone 800 with a smaller thickness, the weight of the casing can be reduced, which helps to improve the energy density of the battery cell using the casing of this embodiment.

[0039] like Figure 2 , Figure 3 and Figure 4 In some embodiments, the outer casing includes a housing 200 and a cover plate body 110. The housing 200 is provided with an opening end 240, and the cover plate body 110 is connected to the opening end 240 and surrounds the housing 200 to form an accommodating space 300. The cover plate body 110 is provided with a pole post 120, and a thinning region 800 is provided on the surface of the cover plate body 110 facing the accommodating space 300 and is located between the edge of the cover plate body 110 and the pole post 120.

[0040] For example, the cover plate body 110 is provided with a through hole extending along its thickness direction, and at least a portion of the pole post 120 passes through the through hole.

[0041] by Figure 2 Taking the structure and orientation shown as an example, the middle part of the cover plate body 110 may not only have the pole post 120, but may also need to have functional structures such as explosion-proof valves or injection holes. If the thinning zone 800 is located in the middle of the cover plate body 110, it will be too close to the functional structures. When the thinning zone 800 is impacted and deformed, it may have an adverse effect on the functional structures. For example, it may cause the explosion-proof valve to break and fail, or cause the seals blocking the injection holes to deform and fail.

[0042] To avoid the aforementioned problems, in this embodiment, the thinning region 800 is disposed between the edge of the cover plate body 110 and the electrode post 120. Even if the thinning region 800 deforms, because it is far from the center of the cover plate body 110, it will not adversely affect the functional structure located in the center of the cover plate body 110, which helps to improve the safety performance of the battery cell.

[0043] Furthermore, by providing the thinning region 800 on the surface of the cover body 110 facing the receiving space 300, the outer surface of the cover body 110 (i.e., the surface away from the receiving space 300) can be kept flat, preventing any impact on the film layer (e.g., top patch) or structural components connected to the cover body 110 due to the provision of the thinning region 800. like Figure 2 , Figure 4 and Figure 4a In some embodiments, the cover body 110 includes two portions along its length (e.g., Figure 2 The first edge 111 is set at intervals in the X direction, and the thinning region 800 extends from the first edge 111 to the pole post 120.

[0044] Combination Figure 2 The cover plate body 110 also includes two width directions (such as...) Figure 2 The second edge 112 is spaced at intervals in the Y direction (as shown in the image), and its length is greater than that of the first edge 111. It is understandable that when the cover plate body 110 is subjected to impact, its bending stiffness in the length direction is relatively weak, and the second edge 112 is more prone to bending deformation than the first edge 111. If the thinning zone 800 is configured to extend from the second edge 112 towards the pole post 120, it may cause the cover plate body 110 to deform excessively after impact, which could increase the risk of cracking in the welded section 400.

[0045] To avoid the above problems, in this embodiment, the thinning area 800 is set to extend from the first edge 111 to the pole post 120. The cover plate body 110 has relatively strong bending stiffness in the width direction. Even with the thinning area 800, the first edge 111 is not prone to large deformation when the cover plate body 110 is impacted. This can share the impact force with the welded part 400 and prevent the welded part 400 from being subjected to additional force due to excessive deformation of the cover plate body 110, thus helping to reduce the risk of cracking of the welded part 400.

[0046] Figure 5 Showing Figure 2 A partial cross-sectional view of section BB.

[0047] like Figure 5 In some embodiments, along the width direction of the cover body 110 (e.g.) Figure 5In the Y direction), the thinning area 800 has a main body area 700 on both sides, and the size of the cover plate body 110 is W1, the size of the thinning area 800 is W2, and the ratio of W2 to W1 is 0.3 to 0.7.

[0048] It should be noted that W1 is the dimension of the planar portion of the surface where the thinning area 800 is located on the cover plate body 110 along the width direction of the cover plate body 110.

[0049] For example, along the width direction of the cover plate body 110, the thinning region 800 is located in the middle of the cover plate body 110.

[0050] For example, the ratio of W2 to W1 can be 0.3, 0.4, 0.5, 0.6 or 0.7.

[0051] If the ratio of W2 to W1 is too large, it may have an adverse effect on the structural strength of the cover plate body 110; if the ratio of W2 to W1 is too small, the thinning area 800 may not deform significantly when the cover plate body 110 is impacted, and the impact force transmitted to the welded part 400 will still be large, and the risk of cracking of the welded part 400 will still be high.

[0052] To avoid the above problems, this embodiment designs the ratio of W2 to W1 to be 0.3 to 0.7. This ensures that the cover plate body 110 has structural strength that meets the process requirements, and that when the cover plate body 110 is subjected to impact, its thinned area 800 can produce the expected deformation to release part of the impact force, thereby effectively reducing the risk of cracking of the welded part 400.

[0053] When the substrate 500 is configured as the cover plate body 110, the effect of setting the thinning region 800 can be demonstrated by the following data.

[0054] Comparative Example 1 This embodiment provides a battery cell with a cover plate body 110 having a thickness of 3mm, an electrode assembly 600 having an overall size of 273.9mm×72.83mm×215.22mm, and a weight of 9.9kg. The cover plate body 110 does not have a thinning area 800.

[0055] Example 1 Example 1 provides a battery cell that differs from Comparative Example 1 only in that a thinning region 800 is provided between the first edge 111 and the terminal post 120 in the cover plate body 110. The thickness of the thinning region 800 is 1.6 mm. The thinning region 800 extends along the length of the cover plate body 110 and has an extension length of 10 mm. The thinning region 800 and the main body region 700 are connected by a slope, and the width of the slope is 1 mm. The ratio of W2 to W1 is 0.2 (where W2 is 14.2 mm and W1 is 71.1 mm).

[0056] Example 2 Example 2 provides a battery cell that differs from Example 1 only in that the ratio of W2 to W1 is 0.4 (where W2 is 28.4 mm and W1 is 71.1 mm).

[0057] Example 3 Example 3 provides a battery cell that differs from Example 1 only in that the ratio of W2 to W1 is 0.5 (where W2 is 35.6 mm and W1 is 71.1 mm).

[0058] Example 4 Example 4 provides a battery cell that differs from Example 1 only in that the ratio of W2 to W1 is 0.7 (where W2 is 49.8 mm and W1 is 71.1 mm).

[0059] Vibration tests were conducted on the battery cells provided in Comparative Example 1, Example 1, Example 2, Example 3 and Example 4. The experimental data are shown in Table 1.

[0060] Table 1 Test Data

[0061] As can be seen from Table 1, in the vibration test, compared with Comparative Example 1, the force on the welded portion 400 decreased by 2.9% in Example 1, by 6.0% in Example 2, by 6.5% in Example 3, and by 6.6% in Example 4. Although the force on the welded portion 400 of the outer shell decreased in Examples 1 to 4 due to the thinning area 800 provided on the cover plate body 110, and the risk of cracking of the welded portion 400 was correspondingly reduced, the decrease in the force on the welded portion 400 in Example 2 was significantly greater than that in Example 1. For this reason, the ratio of W2 to W1 was designed to be 0.3 to 0.7 in this embodiment.

[0062] like Figure 4 and Figure 4a In some embodiments, along the length direction of the cover body 110 (e.g.) Figure 4In the X direction), the minimum straight-line distance between the first edge 111 and the pole post 120 is L1, the extension length of the thinning region 800 is L2, and the ratio of L2 to L1 is 0.25 to 0.6.

[0063] For example, the ratio of L2 to L1 can be 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55 or 0.6.

[0064] If the ratio of L2 to L1 is too large, the thinning zone 800 will be too close to the electrode post 120. When the thinning zone 800 deforms, it may cause the electrode post 120 to tilt, which may adversely affect the reliability of the connection between the electrode post 120 and the tab of the electrode assembly 600, as well as the reliability of the connection between the electrode post 120 and the external circuit. If the ratio of L2 to L1 is too small, the thinning zone 800 may not deform significantly when the cover plate body 110 is impacted. In this case, the impact force transmitted to the welded part 400 will still be large, and the risk of cracking of the welded part 400 will still be high.

[0065] To avoid the above problems, this embodiment designs the ratio of L2 to L1 to be 0.25 to 0.6, so that when the cover plate body 110 is subjected to impact, its thinning area 800 can produce the expected deformation, which can release part of the impact force, thereby effectively reducing the risk of cracking of the welded part 400, and also avoid causing adverse stress to the electrode post 120, ensuring the reliability of the connection between the electrode post 120 and the electrode assembly 600 and the external circuit.

[0066] like Figure 4 and Figure 4a In some embodiments, the thickness of the thinning region 800 is H2, the thickness of the main body region 700 is H1, and the ratio of H2 to H1 is 0.5 to 0.7.

[0067] For example, the ratio of H2 to H1 can be 0.5, 0.55, 0.6, 0.65, or 0.7.

[0068] If the ratio of H2 to H1 is too large, the thinned area 800 will hardly deform significantly when the outer shell is impacted. Therefore, the impact force transmitted to the welded section 400 will still be relatively large, and the risk of cracking in the welded section 400 will remain high. Alternatively, when the outer shell is impacted, it will be difficult to control the deformation within the thinned area 800, which may adversely affect the functional structure on the cover plate body 110. If the ratio of H2 to H1 is too small, the thickness of the thinned area 800 may be too small, resulting in low structural strength, and cracking may occur when the thinned area 800 deforms.

[0069] To avoid the above problems, this embodiment designs the ratio of H2 to H1 to be 0.5 to 0.7. This ensures that the cover plate body 110 has the structural strength required by the process, and that when the cover plate body 110 is subjected to impact, only the thinned area 800 can produce the expected deformation to release part of the impact force. This effectively reduces the risk of cracking of the welded part 400 and also prevents the cover plate body 110 itself from cracking, which helps to improve the safety performance of the battery cell.

[0070] like Figure 4a In some embodiments, the thickness of the thinning region 800 is H2, the cover plate body 110 is welded to the housing 200 and a welded portion 400 is formed on the cover plate body 110, the welded portion 400 extends from the surface of the cover plate body 110 away from the receiving space 300 to the receiving space 300 and the extension dimension is H3, where H2 > 1.2H3.

[0071] For example, H2 can be 1.25H3, 1.3H3, 1.35H3, 1.4H3, 1.45H3 or 1.5H3.

[0072] If H2 is too small, the thinned area 800 of the cover plate body 110 may be welded through when welding the cover plate body 110 and the shell 200.

[0073] To avoid the above problems, in this embodiment, H2 is designed to be H2 > 1.2H3. When welding the cover plate body 110 and the shell 200, the depth of the molten pool formed by the metal melting can be guaranteed to be less than the thickness of the thinning zone 800. Therefore, the problem of welding through the thinning zone 800 of the cover plate body 110 will not occur, thus ensuring the sealing performance and safety performance of the battery cell.

[0074] Figure 6 The third type of shell structure was demonstrated. Figure 2 Partial cross-sectional diagram of section AA. Figure 7 Showing Figure 6 An enlarged diagram of section E in the middle. Figure 8 Showing Figure 7 A partial cross-sectional diagram of the GG section.

[0075] like Figure 6 , Figure 7 and Figure 8 In some embodiments, the outer shell includes a housing 200 and a cover plate body 110. The housing 200 includes a bottom plate 220 and a plurality of side plates 210. The plurality of side plates 210 enclose each other to form a cylindrical structure. One end of the cylindrical structure is configured as an open end 240, and the other end is connected to the bottom plate 220. The cover plate body 110 is connected to the open end 240 and encloses the housing 200 to form a receiving space 300. A thinning region 800 is disposed on the surface of the side plate 210 facing the receiving space 300.

[0076] For example, the base plate 220 can be rectangular, and each of the four edges of the base plate 220 is connected to a side plate 210. Correspondingly, the cylindrical structure is a square cylindrical structure.

[0077] For example, the bottom plate 220 and four side plates 210 of the housing 200 can be formed by stamping; or, a rectangular plate can be bent along its length and spliced ​​end to end to form four side plates 210, with the splice located on one of the side plates 210, and then the bottom plate 220 is connected to the four side plates 210 to form the housing 200.

[0078] Understandably, the base plate 220 is used to support the electrode assembly 600 within the accommodating space 300. If a thinning area 800 is provided on the base plate 220, then the surface of the base plate 220 facing the electrode assembly 600 will be an uneven surface. Under the action of gravity, the electrode assembly 600 may deform along with the aforementioned uneven surface, which may have an adverse effect on the electrical performance of the electrode assembly 600.

[0079] To avoid the above problems, in this embodiment, the thinning area 800 is set on the surface of the side plate 210 facing the receiving space 300. When the battery cell is placed normally, the side plate 210 does not support the electrode assembly 600. Therefore, even if the surface of the side plate 210 facing the electrode assembly 600 is not flat, it will not have a significant impact on the electrode assembly 600. This can reduce the risk of adverse effects on the electrical and safety performance of the battery due to the thinning area 800 on the casing.

[0080] Furthermore, by placing the thinning region 800 on the surface of the side plate 210 near the receiving space 300, the outer surface of the housing 200 can be kept flat, preventing the thinning region 800 from affecting the film layer (e.g., insulating film) or structural components connected to the housing 200.

[0081] like Figure 6 , Figure 7 and Figure 8 In some embodiments, the side plate 210 has an assembly area 213 along its edge near the opening end 240 for mating with the cover plate body 110. The thickness of the assembly area 213 is not less than the thickness of the thinning area 800, and the thickness of the assembly area 213 is less than the thickness of the main body area 700. The thinning area 800 and the assembly area 213 are along the thickness direction of the side plate 210 (e.g., ...). Figure 6 The projections in the X direction do not overlap.

[0082] For example, Figure 9 Showing Figure 7 A partial cross-sectional diagram of the FF section is shown below. Figure 7 and Figure 9The assembly area 213 is arranged in a ring structure along the inner edge of the opening end 240, and the thickness of the assembly area 213 is uniformly distributed.

[0083] For example, the thinning zone 800 and the main body zone 700 are both located between the assembly zone 213 and the base plate 220.

[0084] It should be noted that during the assembly of the outer shell, at least a portion of the circumferential sidewall of the cover plate body 110 contacts the surface of the assembly area 213. The assembly area 213 of the side plate 210 can limit the cover plate body 110 to prevent translation. When welding the cover plate body 110 and the shell 200, a portion of the assembly area 213 of the side plate 210 near the opening end 240 and a portion of the cover plate body 110 near the edge fuse to form a molten pool. After the molten pool solidifies, the welded portion 400 is formed.

[0085] Based on the foregoing, it can be understood that if the assembly area 213 deforms after the side wall 210 is impacted, it may adversely affect the connection reliability between the housing 200 and the cover plate body 110. To avoid this problem, in this embodiment, when the thinning area 800 is provided on the side plate 210, the projections of the thinning area 800 and the assembly area 213 along the thickness direction of the side plate 210 do not overlap; that is, the thinning area 800 does not extend into the assembly area 213. When the side wall 210 is impacted, the deformation range can be controlled within the thinning area 800, ensuring that the assembly area 213 does not deform. This reduces the risk of cracking in the welded portion 400 and further improves the connection reliability between the cover plate body 110 and the housing 200.

[0086] Figure 10 Showing Figure 6 An enlarged schematic diagram of part D in the middle.

[0087] like Figure 6 , Figure 7 and Figure 10 In some embodiments, a bottom transition portion 230 is formed between the side plate 210 and the bottom plate 220 on the side facing the receiving space 300, the thinning area 800 extends from the assembly area 213 to the bottom plate 220, and the projections of the thinning area 800 and the bottom transition portion 230 along the thickness direction of the side plate 210 do not overlap.

[0088] For example, such as Figure 7 On the surface of the side panel 210 facing the receiving space 300, a top transition region 1000 is provided between the assembly area 213 and the main body area 700. The assembly area 213 is connected to the main body area 700 through the top transition region 1000, and the thickness of the top transition region 1000 gradually decreases from the main body area 700 to the assembly area 213. The thinning region 800 extends through the top transition region 1000 to the edge of the assembly area 213 near the main body area 700.

[0089] For example, the top transition zone 1000 is a slope or an arc surface.

[0090] For example, the bottom transition portion 230 includes a slope or arcuate surface facing the receiving space 300.

[0091] For example, the thinning region 800 extends to the edge of the bottom transition portion 230 away from the bottom plate 220.

[0092] Understandably, providing a bottom transition portion 230 can reduce stress concentration between the side plate 210 and the bottom plate 220, preventing cracks or splits at the connection between the side plate 210 and the bottom plate 220. If the thinning zone 800 extends into the bottom transition portion 230, the thickness of the portion of the bottom transition portion 230 that overlaps with the thinning zone 800 will be reduced, and a large stress concentration may occur at this location.

[0093] Therefore, to avoid the above-mentioned problems, this embodiment ensures that the projections of the thinning area 800 and the bottom transition portion 230 along the thickness direction of the side plate 210 do not overlap. This ensures that the thinning area 800 has a large area, and when the side plate 210 is impacted, the thinning area 800 deforms to release more impact force, effectively reducing the risk of cracking of the welded portion 400. It also avoids the failure of the bottom transition portion 230 due to the setting of the thinning area 800, ensuring that the side plate 210 and the bottom plate 220 form a reliable connection.

[0094] like Figure 2 and Figure 8 In some embodiments, the side plate 210 includes a length direction along the cover body 110 (e.g., Figure 8 Two first side plates 211 are arranged opposite each other in the X direction, and a thinning region 800 is disposed on the first side plate 211; along the width direction of the cover plate body 110 (e.g., in the X direction), the thinning region 800 is disposed on the first side plate 211; Figure 2 and Figure 8 In the Y direction), the thinning area 800 has a main body area 700 on both sides, and the size of the first side plate 211 is W3, the size of the thinning area 800 is W4, and the ratio of W4 to W3 is 0.3 to 0.7.

[0095] It should be noted that W3 is the dimension of the planar portion of the surface where the thinning area 800 is located on the first side plate 211 along the width direction of the cover plate body 110.

[0096] For example, such as Figure 8 The side plate 210 includes two second side plates 212 disposed opposite to each other along the width direction of the cover plate body 110.

[0097] For example, along the width direction of the cover plate body 110, the thinning region 800 is located in the middle of the first side plate 211.

[0098] For example, the ratio of W4 to W3 can be 0.3, 0.4, 0.5, 0.6 or 0.7.

[0099] It should be noted that the area of ​​the first side plate 211 is relatively small, so it is not easy for the shell 200 to bend or deform when it is impacted. By setting the thinning area 800 on the first side plate 211, even if the shell 200 is impacted, the first side plate 211 is not easy to deform to a large extent. While sharing the impact force with the welded part 400, it will not generate additional force on the welded part 400 due to excessive deformation, which helps to reduce the risk of cracking of the welded part 400.

[0100] If the ratio of W4 to W3 is too large, it may have an adverse effect on the structural strength of the first side plate 211; if the ratio of W4 to W3 is too small, the thinned area 800 may not deform significantly when the shell 200 is impacted, and the impact force transmitted to the welded part 400 will still be large, and the risk of cracking of the welded part 400 will still be high.

[0101] To avoid the above problems, this embodiment designs the ratio of W4 to W3 to be 0.3 to 0.7. This ensures that the first side plate 211 has structural strength that meets the process requirements, and that when the shell 200 is subjected to impact, the thinned area 800 of the first side plate 211 can produce the expected deformation to release part of the impact force, thereby effectively reducing the risk of cracking of the welded part 400.

[0102] When the substrate 500 is configured as the first side plate 211, the effect of setting the thinning region 800 can be demonstrated by the following data.

[0103] Comparative Example 2 This embodiment provides a battery cell with an assembly area 213 thickness of 0.8 mm, side plates 210 thickness of 1 mm, an electrode assembly 600 overall size of 273.9 mm × 72.83 mm × 215.22 mm, an electrode assembly 600 weight of 9.9 kg, and no thinning area 800 provided on the side plate 210.

[0104] Example 5 Example 5 provides a battery cell that differs from Comparative Example 2 only in that the first side plate 211 is provided with a thinning area 800, the thickness of the thinning area 800 is 0.8mm, the thinning area 800 extends from the edge of the assembly area 213 near the bottom plate 220 to the edge of the bottom transition portion 230 away from the bottom plate 220, the thinning area 800 and the main body area 700 are connected by a slope transition, and the width of the slope is 1mm, and the ratio of W4 to W3 is 0.2 (where W4 is 14.2mm and W3 is 71.2mm).

[0105] Example 6 Example 6 provides a battery cell that differs from Example 5 only in that the ratio of W4 to W3 is 0.3 (where W4 is 21.4 mm and W3 is 71.2 mm).

[0106] Example 7 Example 7 provides a battery cell that differs from Example 5 only in that the ratio of W4 to W3 is 0.4 (where W4 is 28.4 mm and W3 is 71.2 mm).

[0107] Example 8 Example 8 provides a battery cell that differs from Example 5 only in that the ratio of W4 to W3 is 0.5 (where W4 is 35.6 mm and W3 is 71.2 mm).

[0108] Example 9 Example 9 provides a battery cell that differs from Example 5 only in that the ratio of W4 to W3 is 0.7 (where W4 is 49.8 mm and W3 is 71.2 mm).

[0109] Vibration tests were conducted on the battery cells provided in Comparative Example 2, Example 5, Example 6, Example 7, Example 8 and Example 9. The experimental data are shown in Table 2.

[0110] Table 2 Test Data

[0111] As can be seen from Table 2, in the vibration test, compared with Comparative Example 2, the force on the welded portion 400 in Example 5 increased by 1.4%, and the risk of cracking of the welded portion 400 actually increased; in Example 6, the force on the welded portion 400 decreased by 9.4%, in Example 7 by 13.6%, in Example 8 by 13.0%, and in Example 9 by 13.1%. Although the force on the welded portion 400 of the shell in Examples 6 to 9 decreased, and correspondingly, the risk of cracking of the welded portion 400 also decreased, the decrease in the force on the welded portion 400 in Example 7 was significantly higher than that in Example 6. For this reason, the ratio of W4 to W3 in this example was designed to be 0.3 to 0.7.

[0112] like Figure 8 In some embodiments, the thickness of the thinning region 800 is H4, the thickness of the main body region 700 is H5, and the ratio of H4 to H5 is 0.7 to 0.8.

[0113] For example, the ratio of H4 to H5 can be 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79 or 0.8.

[0114] If the ratio of H4 to H5 is too large, the thinning zone 800 will hardly deform significantly when the shell 200 is impacted. Therefore, the impact force transmitted to the welded section 400 will still be relatively large, and the risk of cracking in the welded section 400 will remain high. Alternatively, when the shell 200 is impacted, it will be difficult to control the deformation within the thinning zone 800. The first side plate 211 may deform significantly, and the shape of the cylindrical structure formed by the side plates 210 will also change, potentially causing compression of the electrode assembly 600. If the ratio of H4 to H5 is too small, the thickness of the thinning zone 800 may be too small, resulting in low structural strength and potential cracking when deformation occurs in the thinning zone 800.

[0115] To avoid the above problems, this embodiment designs the ratio of H4 to H5 to be 0.7 to 0.8. This ensures that the first side plate 211 has the structural strength required by the process, and that when the shell 200 is subjected to an impact, only the thinned area 800 of the first side plate 211 can produce the expected deformation to release part of the impact force. This effectively reduces the risk of cracking of the welded part 400 and also prevents the first side plate 211 itself from cracking, which helps to improve the safety performance of the battery cell.

[0116] like Figure 4 and Figure 8 In some embodiments, a transition region 900 is provided between the thinning region 800 and the main body region 700, and the thickness of the transition region 900 gradually increases from the thinning region 800 to the main body region 700.

[0117] For example, the thickness variation of the transition region 900 can be continuous or phased. When the thickness of the transition region 900 is continuous, the surface of the transition region 900 is constructed as a smooth inclined surface or curved surface; when the thickness of the transition region 900 is phased, the surface of the transition region 900 is constructed as a stepped surface or a step-like surface.

[0118] The transition zone 900 achieves a thickness transition between the thinning zone 800 and the main body zone 700, strengthening the connection between them. This prevents stress concentration at the junction caused by abrupt changes in thickness, which could negatively impact the mechanical strength of the casing. Simultaneously, it enhances the safety of the casing and extends its service life.

[0119] Based on the same inventive concept and in conjunction with the description of the casings of the above embodiments, this embodiment provides a battery cell that has the corresponding technical effects of the casings of the above embodiments, which will not be repeated here.

[0120] A battery cell includes a housing as described in the various embodiments above.

[0121] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0122] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0123] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0124] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application is limited to these examples; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0125] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0126] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A casing, characterized in that, The projection of the outer shell along the height direction is a polygon, the polygon includes a corner disposed between two adjacent edges, the outer shell has a main body area at least at the corner, and the outer shell also has at least one thinning area, the thinning area being located between two adjacent corners; The thickness of the thinned region is less than the thickness of the main body region.

2. The outer casing according to claim 1, characterized in that, The outer casing includes a shell and a cover plate body. The shell is provided with an open end, and the cover plate body is connected to the open end and surrounds the shell to form an accommodating space. The cover plate body is provided with an electrode post, and the thinning area is provided on the surface of the cover plate body facing the receiving space, and is located between the edge of the cover plate body and the electrode post.

3. The outer casing according to claim 2, characterized in that, The cover plate body includes two first edges spaced apart along the length direction, and the thinning area extends from the first edges toward the pole.

4. The outer casing according to claim 3, characterized in that, Along the width direction of the cover plate body, the main body area is provided on both opposite sides of the thinning area, and the size of the cover plate body is W1, the size of the thinning area is W2, and the ratio of W2 to W1 is 0.3 to 0.7; and / or, Along the length of the cover plate body, the minimum straight-line distance between the first edge and the pole post is L1, the extension length of the thinning region is L2, and the ratio of L2 to L1 is 0.25 to 0.6; and / or, The thickness of the thinned region is H2, the thickness of the main region is H1, and the ratio of H2 to H1 is 0.5 to 0.7; and / or, The thickness of the thinning zone is H2. The cover plate body is welded to the shell and a welded portion is formed on the cover plate body. The welded portion extends from the surface of the cover plate body away from the receiving space to the receiving space, and the extension dimension is H3, where H2 > 1.2H3.

5. The outer casing according to claim 1, characterized in that, The outer casing includes a shell and a cover plate body. The shell includes a bottom plate and multiple side plates, which together form a cylindrical structure. One end of the cylindrical structure is configured as an open end, and the other end is connected to the bottom plate. The cover plate body is connected to the open end and together with the shell to form an accommodating space. The thinning zone is disposed on the surface of the side plate facing the receiving space.

6. The outer casing according to claim 5, characterized in that, The side plate has an assembly area along its edge near the opening end for mating with the cover plate body. The thickness of the assembly area is not less than the thickness of the thinning area, and the thickness of the assembly area is less than the thickness of the main body area. The projections of the thinning area and the assembly area along the thickness direction of the side plate do not overlap.

7. The outer casing according to claim 6, characterized in that, A bottom transition portion is formed between the side plate and the bottom plate on the side facing the receiving space. The thinning area extends from the assembly area to the bottom plate, and the projections of the thinning area and the bottom transition portion along the thickness direction of the side plate do not overlap.

8. The outer casing according to claim 7, characterized in that, The side plate includes two first side plates arranged opposite each other along the length direction of the cover plate body, and the thinning area is disposed on the first side plate; Along the width direction of the cover plate body, the main body area is provided on both opposite sides of the thinning area, and the size of the first side plate is W3, the size of the thinning area is W4, and the ratio of W4 to W3 is 0.3 to 0.7; and / or, The thickness of the thinning region is H4, and the thickness of the main region is H5, with the ratio of H4 to H5 being 0.7 to 0.

8.

9. The outer casing according to claim 1, characterized in that, A transition zone is also provided between the thinning zone and the main body zone, and the thickness of the transition zone gradually increases from the thinning zone to the main body zone.

10. A single battery cell, characterized in that, Includes the housing as described in any one of claims 1 to 9.

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