Battery cell housing, battery cell and method of assembling a battery cell

Abstract

The application discloses an electric core shell, an electric core and an assembling method of the electric core, and belongs to the technical field of batteries. The electric core shell comprises a side wall and a bottom wall. The bottom wall is arranged at one end of the side wall. The side wall comprises an opening part, a transition part and a main body part. The transition part is located between the opening part and the main body part. The opening part is located at the end of the side wall away from the bottom wall. The opening part has a first cavity, and the main body part has a second cavity. The projection of the first cavity on the bottom wall is at least partially located outside the projection range of the second cavity on the bottom wall. The transition part of the electric core shell can provide limiting and supporting effects for a top cover assembly, so that the stability of the position of the top cover assembly and the assembling precision are improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cell housing, a cell, and a method for assembling the cell. Background Technology

[0002] A battery cell typically consists of a housing, a top cover assembly, and the inner core. The assembly of the housing and top cover assembly is a critical process. To achieve good sealing and welding, the top cover assembly needs to be precisely positioned at the open end of the housing.

[0003] In related technologies, a step with a gradually changing wall thickness is provided on the inner side wall of the housing. This step abuts against the chamfer of the outer perimeter of the top cover assembly, thereby providing vertical support for the top cover assembly, preventing it from falling into the housing, and ensuring its mounting flatness, thus providing a basis for subsequent sealing processes such as laser welding. However, the wall thickness of the housing's side wall is typically only 0.1mm to 0.2mm, and the step size is extremely small. During the assembly process of the top cover assembly and the housing, due to factors such as manufacturing tolerances and assembly errors, a certain percentage of top cover assemblies may fall into the housing, or unevenness may occur where one side of the top cover assembly is higher than the other side of the housing. Summary of the Invention

[0004] This application provides a battery cell housing with a transition portion that provides limiting and support for the top cover assembly, thereby improving the stability of the top cover assembly's position and assembly accuracy.

[0005] Another objective of this application is to provide a battery cell.

[0006] The third objective of this application is to provide a method for assembling a battery cell.

[0007] To achieve the above objectives, according to a first aspect of this application, a battery cell housing is provided, comprising: a side wall and a bottom wall, the bottom wall being disposed at one end of the side wall, the side wall including an opening, a transition portion and a main body portion, the transition portion being located between the opening portion and the main body portion, and the opening portion being located at the end of the side wall away from the bottom wall; The opening has a first cavity, the main body has a second cavity, and the projection of the first cavity on the bottom wall is at least partially outside the range of the projection of the second cavity on the bottom wall.

[0008] Optionally, the first cavity has a first curved surface, the second cavity has a second curved surface, and the first curved surface and the second curved surface are connected by the transition portion; The radius of curvature of the first surface is smaller than the radius of curvature of the second surface.

[0009] Optionally, the opening includes two first sidewalls disposed opposite each other in a first direction and two second sidewalls disposed opposite each other in a second direction, the first direction and the second direction intersect, and the first curved surface is located between adjacent first sidewalls and second sidewalls.

[0010] Optionally, the main body includes two third sidewalls disposed opposite to each other in the first direction and two fourth sidewalls disposed opposite to each other in the second direction, the second curved surface being located between adjacent third sidewalls and fourth sidewalls; or, The main body includes two fourth sidewalls disposed opposite each other in the second direction, the second curved surface is located between two adjacent fourth sidewalls, and the two second curved surfaces located on the same side of the main body in the first direction are connected to each other.

[0011] Optionally, in the third direction, the end of the opening facing the bottom wall is located above the end of the main body portion away from the bottom wall; or, In the third direction, the end of the opening facing the bottom wall is flush with the end of the main body away from the bottom wall; or... In the third direction, the end of the opening facing the bottom wall is located below the end of the main body that is away from the bottom wall.

[0012] According to a second aspect of this application, a battery cell is provided, including a top cover assembly, an inner core, and a battery cell housing as described in any one of the above, wherein at least a portion of the top cover assembly is located in a first cavity, and at least a portion of the inner core is located in a second cavity. At least a portion of the top cover assembly abuts against the transition portion.

[0013] Optionally, the inner core is a rolled core, and the inner core has a third curved surface in a first direction. The third curved surface is disposed corresponding to the second curved surface, and the radius of curvature of the third curved surface is less than or equal to the radius of curvature of the second curved surface.

[0014] Optionally, the top cover assembly has a fourth curved surface, which is disposed corresponding to the first curved surface, and the radius of curvature of the fourth curved surface is less than or equal to the radius of curvature of the first curved surface.

[0015] Optionally, the diameter of the circumscribed circle corresponding to the curvature of the third surface is equal to the thickness of the inner core in the second direction; and / or, The number of inner cores is one or more, and when the number of inner cores is multiple, the multiple inner cores are arranged side by side along the second direction.

[0016] Optionally, the battery cell is a square battery cell.

[0017] According to a third aspect of this application, a method for assembling a battery cell is provided, applicable to a battery cell as described in any one of the above claims, the assembly method comprising: Insert the inner core through the opening in the cell housing, allowing it to enter the second cavity; The top cover assembly is fitted into the opening of the cell housing; Laser welding is performed on the seam between the top cover assembly and the opening of the cell housing.

[0018] In the battery cell housing of this application embodiment, the sidewall is divided into an opening, a transition portion, and a main body portion. The projection of the first cavity of the opening portion onto the bottom wall is at least partially located outside the projection of the second cavity of the main body portion onto the bottom wall. That is, the first cavity has a larger cross-sectional area in the horizontal direction relative to the second cavity, and at least a portion of the first cavity is offset outward relative to the second cavity. This structure makes the inner cavity size of the opening portion larger than the inner cavity size of the main body portion in at least one direction, thereby forming a stable support structure between the opening portion and the main body portion. The transition portion is located at the position of the transition portion and is used to abut against the top cover assembly. When the top cover assembly is installed into the battery cell housing, it can enter the first cavity and abut against the transition portion. The transition portion provides a limiting and supporting function for the top cover assembly. The transition portion can provide a wider and more stable support surface, preventing the top cover assembly from falling into the battery cell housing or tilting, thereby improving the stability and assembly accuracy of the top cover assembly position.

[0019] The battery cell in this application embodiment includes a battery cell housing, and the battery cell has the beneficial effects produced by the battery cell housing, which will not be described in detail here.

[0020] The battery cell assembly method of this application embodiment is applied to battery cells. The battery cell assembly method has the beneficial effects produced by the battery cell, which will not be described in detail here.

[0021] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0024] Figure 1This is a three-dimensional structural diagram of the battery cell provided in an exemplary embodiment of this application; Figure 2 This is a schematic planar structure diagram of a battery cell provided in an exemplary embodiment of this application from one perspective; Figure 3 This is a schematic diagram of the planar structure of the battery cell provided in an exemplary embodiment of this application from another perspective; Figure 4 It is along Figure 3 Schematic diagram of the cross section of line AA; Figure 5 yes Figure 4 A magnified schematic diagram of the local structure at point A; Figure 6 This is a three-dimensional structural diagram of a battery cell housing provided in an exemplary embodiment of this application; Figure 7 This is a schematic diagram of a planar structure of a battery cell housing provided in an exemplary embodiment of this application; Figure 8 This is a three-dimensional structural schematic diagram of another battery cell housing provided in an exemplary embodiment of this application; Figure 9 This is a schematic diagram of another planar structure of a battery cell housing provided in an exemplary embodiment of this application.

[0025] Explanation of reference numerals in the attached figures: 100. Battery cell; 1. Battery cell housing; 11. Side wall; 111. Opening; 1111. First cavity; 1112. First curved surface; 1113. First side wall; 1114. Second side wall; 112. Transition section; 113. Main body; 1131. Second cavity; 1132. Second curved surface; 1133. Third side wall; 1134. Fourth side wall; 12. Bottom wall; 2. Top cover assembly; 21. Cover plate; 211. Fourth curved surface; 22. Lower plastic; 23. Explosion-proof valve; 24. Electrode terminal; 3. Inner core; 31. Third curved surface; 32. Tab; X, First direction; Y, Second direction; Z, Third direction. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "up," "down," "left," and "right" generally refer to up, down, left, and right in the actual use or working state of the device, specifically the drawing directions in the accompanying drawings.

[0027] In this application, unless otherwise expressly specified and limited, the terms "connected," "linked," "stacked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] This application provides a battery cell housing, a battery cell, and a method for assembling the battery cell, which are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments of this application. Furthermore, in the following embodiments, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.

[0029] According to the first aspect of this application, referring to Figure 1 and Figure 2 One embodiment of this application provides a battery cell housing 1. The interior of the battery cell housing 1 is used to accommodate an inner core 3, and the inner core 3 is sealed by a top cover assembly 2. The inner core 3 can be a wound core or a stacked core, etc. In this application, a wound core is used as an example for description. The battery cell housing 1 can have a first direction X, a second direction Y, and a third direction Z that intersect each other. The first direction X can be the length direction of the battery cell housing 1. The second direction Y can be the width direction of the battery cell housing 1. The third direction Z can be the height direction of the battery cell housing 1.

[0030] Reference Figure 1The battery cell housing 1 may include a side wall 11 and a bottom wall 12, with the bottom wall 12 disposed at one end of the side wall 11. The side wall 11 and the bottom wall 12 may be fixedly connected by integral stretching, stamping, or welding to form a container structure with one end open and the other closed, for accommodating the inner core 3 and electrolyte, etc. The battery cell housing 1 may be a square housing, etc. The material of the battery cell housing 1 may be aluminum or aluminum alloy, which has good thermal conductivity and light weight, which is beneficial to the heat dissipation and weight reduction of the battery cell 100. Of course, in other embodiments, the battery cell housing 1 may also be made of other metal materials or composite materials.

[0031] The sidewall 11 may include an opening 111, a transition portion 112, and a main body portion 113. The transition portion 112 may be located between the opening 111 and the main body portion 113, and the opening 111 may be located at the end of the sidewall 11 away from the bottom wall 12. It is understood that, in the third direction Z, the opening 111 is located at the end of the sidewall 11 away from the bottom wall 12, and the opening 111 is the opening end of the cell housing 1. The main body portion 113 is the main part of the sidewall 11, extending from the transition portion 112 to the bottom wall 12. The transition portion 112 may be a structure connecting the opening 111 and the main body portion 113. The transition portion 112 may have various forms; for example, the transition portion 112 may be an annular region with a specific contour surrounding the cell housing 1, or it may be a local structure located at the four corners of the cell housing 1.

[0032] Among them, reference Figures 3 to 6 The opening 111 may have a first cavity 1111, and the main body 113 may have a second cavity 1131. The first cavity 1111 and the second cavity 1131 are interconnected and together constitute the internal space of the cell housing 1, for accommodating components such as the top cover assembly 2 and the inner core 3 of the cell 100. The projection of the first cavity 1111 onto the bottom wall 12 is at least partially outside the range of the projection of the second cavity 1131 onto the bottom wall 12. That is, the cross-sectional area of ​​the first cavity 1111 is larger than the cross-sectional area of ​​the second cavity 1131 in at least one direction. In other words, from the opening 111 to the main body 113, the internal space of the cell housing 1 undergoes a contraction or step-like change, and this change occurs in the region where the transition portion 112 is located.

[0033] As an example, the projection of the first cavity 1111 onto the bottom wall 12, that is, the projection of the inner contour of the opening 111 onto the plane of the bottom wall 12, can protrude outward in the four corner regions, exceeding the range of the projection of the second cavity 1131 onto the bottom wall 12, that is, the projection of the inner contour of the main body 113 onto the plane of the bottom wall 12. In other words, the inner cavity size of the opening 111 is larger than the inner cavity size of the main body 113 in the four corner regions, forming an outwardly expanding structure of the opening 111.

[0034] This creates a limiting structure between the opening 111 and the main body 113, namely the location of the transition portion 112. The transition portion 112 can be a stepped surface or transition surface formed by the dimensional change between the first cavity 1111 and the second cavity 1131. Since the transition portion 112 is formed by the structural change of the side wall 11 of the cell housing 1 itself, its size and strength can be designed to be larger than the steps in the prior art, thus providing stable and reliable support. At least a portion of the top cover assembly 2 forms surface contact with the transition portion 112, rather than point contact or extremely small area contact as in the prior art, thereby effectively preventing the top cover assembly 2 from falling into the cell housing 1 or becoming uneven during assembly.

[0035] When the top cover assembly 2 is inserted into the cell housing 1 through the opening 111, the top cover assembly 2 first enters the first cavity 1111. Since the size of the first cavity 1111 is larger than that of the second cavity 1131 in the corner area, when the top cover assembly 2 continues to move downward, the corner of the top cover assembly 2 will be blocked by the transition part 112 and cannot continue to enter the second cavity 1131, thereby achieving the limitation and support of the top cover assembly 2.

[0036] In this application, the sidewall 11 is divided into an opening 111, a transition portion 112, and a main body 113. The projection of the first cavity 1111 of the opening 111 onto the bottom wall 12 is defined to be at least partially outside the projection of the second cavity 1131 of the main body 113 onto the bottom wall 12. Specifically, the first cavity 1111 has a larger cross-sectional area in the horizontal direction relative to the second cavity 1131, and at least a portion of the first cavity 1111 is offset outward relative to the second cavity 1131. This structure results in the inner cavity size of the opening 111 being larger than the inner cavity size of the main body 113 in at least one direction, thereby forming a stable support structure between the opening 111 and the main body 113. The transition portion 112 is located at this position and serves to abut against the top cover assembly 2. When the top cover assembly 2 is installed into the cell housing 1, the top cover assembly 2 can enter the first cavity 1111 and abut against the transition portion 112, which provides both positioning and support for the top cover assembly 2. Compared to the narrow steps in the prior art, the transition portion 112 in this application can provide a wider and more stable support surface, preventing the top cover assembly 2 from falling into the cell housing 1 or tilting, thereby improving the stability and assembly accuracy of the top cover assembly 2. Simultaneously, it makes the fit between the top cover assembly 2 and the cell housing 1 more reliable, facilitating the smooth progress of subsequent welding processes, reducing welding defects, and thus improving the yield and quality of the cell 100.

[0037] In some embodiments, refer to Figure 6 and Figure 7The first cavity 1111 may have a first curved surface 1112, and the second cavity 1131 may have a second curved surface 1132. The first curved surface 1112 and the second curved surface 1132 can be connected by a transition portion 112. In this embodiment, the first curved surface 1112 may be located at the four corners of the opening 111, and is an arc transition surface formed by the inner wall of the opening 111 at the corner, i.e., the R-angle of the opening 111. The second curved surface 1132 may be located at the four corners of the main body 113, and is an arc transition surface formed by the inner wall of the main body 113 at the corner, i.e., the R-angle of the main body 113. Correspondingly, the transition portions 112 may be provided at the corresponding positions of the four corners of the opening 111. When the top cover assembly 2 is assembled, the top cover assembly 2 can abut against the four transition portions 112, and the force is evenly distributed at four points, thereby improving the stability of the limiting support.

[0038] Both the first curved surface 1112 and the second curved surface 1132 can be rounded or chamfered. In this embodiment, both the first curved surface 1112 and the second curved surface 1132 are rounded. The radius of curvature of the first curved surface 1112 is smaller than that of the second curved surface 1132. By setting the first curved surface 1112 and the second curved surface 1132 with different radii of curvature and connecting them using the transition portion 112, the inner cavity profile of the opening 111 can be made sharper than that of the main body 113. This allows for a tighter fit with the top cover assembly 2 and the inner core 3. Specifically, the smaller radius of curvature of the first curved surface 1112 allows for better matching with the fourth curved surface 211 of the top cover assembly 2, further improving positioning accuracy and support stability. The second curved surface 1132 has a larger radius of curvature and is gentler than the first curved surface 1112, which better accommodates the third curved surface 31 of the inner core 3 and reduces the gap between the cell housing 1 and the inner core 3, thereby improving the space utilization of the cell housing 1. With the same external dimensions, a larger volume inner core 3 can be accommodated, thus increasing the energy density of the cell 100. Simultaneously, it provides better support for the third curved surface 31 of the inner core 3, reducing stress concentration and the risk of wrinkling, and lowering the risk of deformation of the inner core 3 under charge-discharge cycles, thermal expansion and contraction, and vibration environments. This helps maintain the long-term stability of the internal structure of the cell 100 and extends its cycle life. It also reduces the accumulation of free electrolyte and foreign matter on the third curved surface 31 of the inner core 3, reducing the risk of corrosion. Furthermore, the larger contact area facilitates the dissipation of heat from the inner core 3 through the cell housing 1, thereby improving heat dissipation and enhancing safety.

[0039] In some embodiments, refer to Figure 1 and Figure 6The opening 111 may include two first sidewalls 1113 disposed opposite to each other in a first direction X and two second sidewalls 1114 disposed opposite to each other in a second direction Y. The first direction X and the second direction Y intersect. In this embodiment, the first direction X and the second direction Y may be perpendicular to each other. Of course, in other embodiments, the first direction X and the second direction Y may intersect at other angles, such as 60 degrees or 120 degrees.

[0040] In other words, the opening 111 can be enclosed by two first sidewalls 1113 and two second sidewalls 1114 to form a square structure, wherein the two first sidewalls 1113 are arranged opposite each other along a first direction X, and the two second sidewalls 1114 are arranged opposite each other along a second direction Y. A first curved surface 1112 can be located between adjacent first sidewalls 1113 and second sidewalls 1114. Specifically, the opening 111 can have four corners, each corner being enclosed by an adjacent first sidewall 1113 and a second sidewall 1114, with a first curved surface 1112 provided at each corner. The four first curved surfaces 1112 can be located at the four corners of the opening 111.

[0041] In some embodiments, refer to Figure 6 and Figure 7 The main body 113 may include two third sidewalls 1133 opposite to each other in a first direction X and two fourth sidewalls 1134 opposite to each other in a second direction Y. That is, the main body 113 may be enclosed by the two third sidewalls 1133 and the two fourth sidewalls 1134 to form a square structure, wherein the two third sidewalls 1133 are opposite to each other along the first direction X, and the two fourth sidewalls 1134 are opposite to each other along the second direction Y. A second curved surface 1132 may be located between adjacent third sidewalls 1133 and fourth sidewalls 1134. Specifically, the main body 113 may have four corners, each corner being enclosed by an adjacent third sidewall 1133 and a fourth sidewall 1134, with a second curved surface 1132 provided at each corner. The four second curved surfaces 1132 may be located at the four corners of the main body 113.

[0042] Or, refer to Figure 8 and Figure 9 The main body 113 may include two fourth sidewalls 1134 disposed opposite each other in the second direction Y. The second curved surface 1132 may be located between two adjacent fourth sidewalls 1134, and the two second curved surfaces 1132 located on the same side of the main body 113 in the first direction X are connected to each other. That is, the main body 113 may include two fourth sidewalls 1134 disposed opposite each other in the second direction Y, but does not include third sidewalls 1133 disposed opposite each other in the first direction X, that is, the main body 113 does not have third sidewalls 1133 at both ends in the first direction X.

[0043] The main body 113 has two opposing fourth sidewalls 1134 in the second direction Y, and at one end of the main body 113 in the first direction X (i.e., the end in the length direction), two second curved surfaces 1132 at that end are connected to each other to form a continuous arc-shaped surface. Similarly, at the other end of the main body 113 in the first direction X, two second curved surfaces 1132 at that end are also connected to each other to form a continuous arc-shaped surface. This structure is suitable for scenarios where the radius of curvature of the third curved surface 31 of the inner core 3 is large or where space utilization is required to a greater extent. Since both ends of the main body 113 are arc-shaped surfaces, they can better match the third curved surfaces 31 at both ends of the inner core 3, further reducing the gap between the third curved surface 31 of the inner core 3 and the cell housing 1, and improving space utilization. At the same time, the arc-shaped ends of the main body 113 can provide more uniform support for the third curved surface 31 of the inner core 3, which helps to reduce stress concentration.

[0044] This application provides two structural schemes for the main body 113. In the first scheme, the main body 113, similar to the opening 111, is enclosed by two third sidewalls 1133 and two fourth sidewalls 1134 to form a square structure, with the second curved surface 1132 located at the four corners of the main body 113. This structure is suitable for most applications of square battery cells, especially for applications with multiple inner cores 3. In the second scheme, the main body 113 does not have third sidewalls 1133 in the first direction X, but instead, the second curved surface 1132 directly connects to the two fourth sidewalls 1134 located in the second direction Y. In other words, the two ends of the main body 113 in the first direction X are arc-shaped (composed of the second curved surface 1132), and the two second curved surfaces 1132 located on the same side are connected to each other to form a continuous arc surface. This structure makes the main body 113 arc-shaped at both ends in the first direction X, which can better match the third curved surface 31 of the inner core 3. It is suitable for scenarios where the radius of curvature of the third curved surface 31 of the inner core 3 is large or where space utilization is required. It is especially suitable for application scenarios where there is only one inner core 3.

[0045] The transition portion 112 can be understood as a transition surface connecting the first curved surface 1112 and the second curved surface 1132, or a transition wall connecting the first side wall 1113 and the third side wall 1133, and the second side wall 1114 and the fourth side wall 1134. The surface of the transition portion 112 located inside the cell housing 1 can be a smooth curved surface, or an inclined surface or a stepped surface with a certain angle. In this embodiment, the contour of the transition portion 112 can match the contour of the lower surface of the top cover assembly 2 to achieve maximum contact support area.

[0046] In this embodiment, the battery cell housing 1 can be integrally formed using processes such as stamping and stretching or extrusion molding, which offers good manufacturing feasibility and cost advantages. A first curved surface 1112 and a second curved surface 1132 with different radii of curvature, as well as a transition portion 112 connecting the two, can be formed in a single process. This integral molding manufacturing method improves the structural strength and dimensional accuracy of the battery cell housing 1 while reducing manufacturing costs.

[0047] In some embodiments, refer to Figure 5 and Figure 6 The first sidewall 1113 and the third sidewall 1133 are located on the same side and connected to each other in the first direction X, together forming the sidewall 11 of the cell housing 1 in the first direction X. Similarly, the second sidewall 1114 and the fourth sidewall 1134 are located on the same side and connected to each other in the second direction Y, together forming the sidewall 11 of the cell housing 1 in the second direction Y.

[0048] In the third direction Z, the end of the opening 111 facing the bottom wall 12 (i.e., the lower end of the opening 111) is located above the end of the main body 113 away from the bottom wall 12 (i.e., the upper end of the main body 113). In other words, there can be a gap between a portion of the lower end of the opening 111 and a portion of the upper end of the main body 113. This gap constitutes the extension range of the transition portion 112 in the height direction, thereby allowing the transition portion 112 to be inclined from top to bottom.

[0049] Alternatively, in the third direction Z, the end of the opening 111 facing the bottom wall 12 is flush with the end of the main body 113 away from the bottom wall 12. That is, the transition portion 112 can be located at the junction of the opening 111 and the main body 113, and the lower end of the opening 111 and the upper end of the main body 113 are at the same height in the third direction Z, so that the transition portion 112 can be horizontally arranged.

[0050] Alternatively, in the third direction Z, the end of the opening 111 facing the bottom wall 12 is located below the end of the main body 113 away from the bottom wall 12. That is, a portion of the lower end of the opening 111 is lower than a portion of the upper end of the main body 113, thereby allowing the transition portion 112 to be inclined from bottom to top.

[0051] This application provides various relative positional relationships between the opening 111 and the main body 113 in the third direction Z. The position of the transition portion 112 determines the boundary between the opening 111 and the main body 113, and also determines the installation depth of the top cover assembly 2 within the cell housing 1. It can be selected according to actual design requirements (such as the thickness of the top cover assembly 2, the height of the inner core 3, and the overall height of the cell housing 1), making the technical solution of this application more flexible and adaptable. When the lower end of the opening 111 is above the upper end of the main body 113, that is, when the transition portion 112 is located at a higher position in the cell housing 1, the height of the first cavity 1111 is smaller, and the top cover assembly 2 is installed shallower within the cell housing 1. When the lower end of the opening 111 is flush with the upper end of the main body 113, the transition portion 112 is located at the junction of the opening 111 and the main body 113. When the lower end of the opening 111 is located below the upper end of the main body 113, that is, when the transition part 112 is located at a lower position of the cell housing 1, the height of the first cavity 1111 is relatively large, and the top cover assembly 2 is installed deeper inside the cell housing 1.

[0052] According to the second aspect of this application, referring to Figures 1 to 3 One embodiment of this application provides a battery cell 100, which can be a prismatic battery cell. Prismatic battery cells have advantages such as compact structure, high space utilization, and good assembly efficiency, and are the mainstream product form in the field of power batteries.

[0053] The battery cell 100 may include a top cover assembly 2, an inner core 3, and a battery cell housing 1 as described above. (Refer to...) Figure 5 At least a portion of the top cover assembly 2 may be located within the first cavity 1111, and at least a portion of the inner core 3 may be located within the second cavity 1131. It is understood that the top cover assembly 2 is primarily located within the first cavity 1111, and a portion of the top cover assembly 2 may extend into the second cavity 1131. The inner core 3 is primarily located within the second cavity 1131, and a portion of the inner core 3 may also be located within the first cavity 1111. At least a portion of the top cover assembly 2 may abut against the transition portion 112.

[0054] The top cover assembly 2 can be installed in the opening 111 of the cell housing 1, and is at least partially accommodated in the first cavity 1111. At least a portion of the top cover assembly 2 forms an abutment fit with the transition portion 112. The transition portion 112 limits and supports the top cover assembly 2, ensuring that the top cover assembly 2 is in the correct position in the opening 111 of the cell housing 1, and preventing the top cover assembly 2 from falling into the second cavity 1131 or from being unevenly assembled.

[0055] In some embodiments, refer to Figure 1 and Figure 5The inner core 3 can be a rolled core, and the inner core 3 can have a third curved surface 31 in the first direction X, that is, the radius (R) of the inner core 3. The third curved surface 31 can be set correspondingly to the second curved surface 1132, that is, the position of the third curved surface 31 corresponds to the position of the second curved surface 1132. The radius of curvature of the third curved surface 31 can be less than or equal to the radius of curvature of the second curved surface 1132.

[0056] Since the radius of curvature of the third surface 31 is less than or equal to the radius of curvature of the second surface 1132, when the inner core 3 is installed into the battery cell housing 1, the third surface 31 of the inner core 3 and the second surface 1132 of the battery cell housing 1 form a close or nearly close fit. That is, there may be a very small gap between the third surface 31 and the second surface 1132, or they may be completely close together. This fit not only ensures that the inner core 3 can be smoothly installed into the battery cell housing 1 without causing assembly difficulties due to interference fit, but also minimizes the gap between the third surface 31 of the inner core 3 and the battery cell housing 1, thus improving space utilization.

[0057] Meanwhile, the second curved surface 1132 can support the third curved surface 31. During the use of the cell 100, the inner core 3 expands with charge and discharge cycles. The second curved surface 1132 provides constraint and support to the third curved surface 31 of the inner core 3, thereby reducing stress concentration at the third curved surface 31 of the inner core 3. This helps prevent wrinkling and deformation of the electrode sheets of the inner core 3 and lithium plating, thus improving the capacity of the cell 100 and extending its cycle life.

[0058] Furthermore, because the gap between the third curved surface 31 and the second curved surface 1132 is very small or completely fitted, the contact area between the inner core 3 and the cell housing 1 is increased, which facilitates the dissipation of heat generated inside the cell 100 through the cell housing 1, improving the heat dissipation effect of the cell 100. At the same time, the reduction in gap also reduces the accumulation of free electrolyte and foreign matter at the third curved surface 31 of the inner core 3, reducing the risk of corrosion.

[0059] In some embodiments, refer to Figure 1 and Figure 5 The top cover assembly 2 may have a fourth curved surface 211. In this embodiment, the top cover assembly 2 may include a cover plate 21. The fourth curved surface 211 may be located at the four corners of the cover plate 21, i.e., the radius of curvature (R-angle) of the cover plate 21. The fourth curved surface 211 may be correspondingly arranged with the first curved surface 1112, i.e., the position of the fourth curved surface 211 corresponds to the position of the first curved surface 1112. The radius of curvature of the fourth curved surface 211 may be less than or equal to the radius of curvature of the first curved surface 1112.

[0060] The cover plate 21 may have a fourth curved surface 211 at each of its four corners, which can be a rounded transition at the corners of the cover plate 21. The radius of curvature of the fourth curved surface 211 is less than or equal to the radius of curvature of the first curved surface 1112. When the top cover assembly 2 is installed into the first cavity 1111, the fourth curved surface 211 of the cover plate 21 is positioned opposite to the first curved surface 1112 of the cell housing 1, and a mating relationship is formed between the two. Since the radius of curvature of the fourth curved surface 211 is less than or equal to the radius of curvature of the first curved surface 1112, the cover plate 21 can smoothly enter the first cavity 1111 and form a mating with the first curved surface 1112, realizing the precise positioning of the cover plate 21 in the opening 111, which is beneficial for subsequent welding and sealing.

[0061] Reference Figure 1 The top cover assembly 2 may further include a lower plastic 22. The lower plastic 22 may be disposed on the side of the cover plate 21 facing the first cavity 1111, that is, the lower plastic 22 may be disposed on the lower side of the cover plate 21. At least a portion of the lower plastic 22 may abut against the transition portion 112. As part of the top cover assembly 2, the lower plastic 22 can form an abutting fit with the transition portion 112 to limit the positioning of the top cover assembly 2. The lower plastic 22 may be made of an elastic insulating material, which can provide a certain buffering and sealing effect when abutting against the transition portion 112.

[0062] Reference Figure 1 and Figure 3 The top cover assembly 2 may also include an explosion-proof valve 23 and electrode terminals 24. The explosion-proof valve 23 may be disposed on the cover plate 21 and is used to release pressure when the internal pressure of the battery cell 100 is too high, preventing the battery cell 100 from exploding. The electrode terminals 24 may be disposed on the cover plate 21 and may include a positive terminal and a negative terminal for electrical connection with an external circuit. The inner core 3 may be provided with tabs 32, which may include a positive tab and a negative tab. The tabs 32 may be electrically connected to the electrode terminals 24 to realize the electrical connection between the inner core 3 and the external circuit.

[0063] In some embodiments, the diameter of the circumscribed circle corresponding to the curvature of the third surface 31 may be equal to the thickness of the inner core 3 in the second direction Y. It should be noted that "the diameter of the circumscribed circle corresponding to the curvature of the third surface 31 is equal to the thickness of the inner core 3 in the second direction Y" means that the diameter of the circumscribed circle corresponding to the curvature of the third surface 31 is approximately equal to the thickness of the inner core 3 in the second direction Y, not absolutely equal. The difference between the diameter of the circumscribed circle corresponding to the curvature of the third surface 31 and the thickness of the inner core 3 in the second direction Y is within a preset range, for example, within 10%.

[0064] The number of inner cores 3 can be one or more. When there are multiple inner cores 3, the multiple inner cores 3 can be arranged side by side along the second direction Y. For example, when there are two inner cores 3, the two inner cores 3 are arranged side by side along the second direction Y. When there are four inner cores 3, the four inner cores 3 are arranged side by side along the second direction Y. The battery cell housing 1 of this application can be applied to different configurations of winding cores, such as single winding core, double winding core, and four winding core, and has good versatility.

[0065] According to a third aspect of this application, one embodiment of this application provides a method for assembling a battery cell, applied to the battery cell 100 described above. The assembly method may include the following steps.

[0066] A cell housing 1 is provided. The cell housing 1 can be manufactured by processes such as aluminum stretching and stamping.

[0067] An inner core 3 is provided. The inner core 3 can be formed by a winding process, forming a third curved surface 31 at both ends. The diameter of the third curved surface 31 can be equal to the thickness of the inner core 3 in the second direction Y.

[0068] Insert the inner core 3 into the cell housing 1. Insert the inner core 3 through the opening 111 of the cell housing 1, allowing it to enter the second cavity 1131. During insertion, the third curved surface 31 of the inner core 3 should be roughly aligned with the second curved surface 1132 of the cell housing 1 to reduce the gap between them.

[0069] A top cover assembly 2 is provided. A pre-assembled top cover assembly 2 is provided, wherein the cover plate 21 has a fourth curved surface 211, the fourth curved surface 211 matching the radius of curvature of the first curved surface 1112 of the cell housing 1.

[0070] Install the top cover assembly 2. Assemble the top cover assembly 2 into the opening 111 of the cell housing 1, ensuring it at least partially enters the first cavity 1111. Under gravity or external pressure, the top cover assembly 2 moves downwards until the lower plastic 22 contacts and abuts against the transition portion 112 of the cell housing 1. Due to the support of the transition portion 112, the top cover assembly 2 is precisely positioned at a preset height and remains horizontal. At this time, a small gap or contact is formed between the fourth curved surface 211 of the cover plate 21 and the first curved surface 1112 of the cell housing 1.

[0071] Welding and sealing. Laser welding is performed on the joint between the cover plate 21 of the top cover assembly 2 and the opening 111 of the cell housing 1 to form a continuous and dense weld, thereby sealing the cell 100.

[0072] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0073] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0074] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0075] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A battery cell housing, characterized in that, include: The sidewall and the bottom wall are provided at one end of the sidewall. The sidewall includes an opening, a transition portion and a main body portion. The transition portion is located between the opening portion and the main body portion. The opening portion is located at the end of the sidewall away from the bottom wall. The opening has a first cavity, the main body has a second cavity, and the projection of the first cavity on the bottom wall is at least partially outside the range of the projection of the second cavity on the bottom wall.

2. The cell housing according to claim 1, characterized in that, The first cavity has a first curved surface, and the second cavity has a second curved surface. The first curved surface and the second curved surface are connected by the transition portion. The radius of curvature of the first surface is smaller than the radius of curvature of the second surface.

3. The cell housing according to claim 2, characterized in that, The opening includes two first sidewalls disposed opposite each other in a first direction and two second sidewalls disposed opposite each other in a second direction. The first direction and the second direction intersect, and the first curved surface is located between adjacent first sidewalls and second sidewalls.

4. The cell housing according to claim 3, characterized in that, The main body includes two third sidewalls disposed opposite to each other in the first direction and two fourth sidewalls disposed opposite to each other in the second direction, the second curved surface being located between adjacent third sidewalls and fourth sidewalls; or, The main body includes two fourth sidewalls disposed opposite each other in the second direction, the second curved surface is located between two adjacent fourth sidewalls, and the two second curved surfaces located on the same side of the main body in the first direction are connected to each other.

5. The cell housing according to claim 1, characterized in that, In a third-party orientation, the end of the opening facing the bottom wall is located above the end of the main body portion away from the bottom wall; or, In the third direction, the end of the opening facing the bottom wall is flush with the end of the main body away from the bottom wall; or... In the third direction, the end of the opening facing the bottom wall is located below the end of the main body that is away from the bottom wall.

6. A battery cell, characterized in that, The battery includes a top cover assembly, an inner core, and a cell housing as described in any one of claims 1 to 5, wherein at least a portion of the top cover assembly is located within the first cavity, and at least a portion of the inner core is located within the second cavity. At least a portion of the top cover assembly abuts against the transition portion.

7. The battery cell according to claim 6, characterized in that, The inner core is a rolled core, and the inner core has a third curved surface in a first direction. The third curved surface is correspondingly arranged with the second curved surface, and the radius of curvature of the third curved surface is less than or equal to the radius of curvature of the second curved surface.

8. The battery cell according to claim 6, characterized in that, The top cover assembly has a fourth curved surface, which is disposed corresponding to the first curved surface, and the radius of curvature of the fourth curved surface is less than or equal to the radius of curvature of the first curved surface.

9. The battery cell according to claim 7, characterized in that, The diameter of the circumcircle corresponding to the curvature of the third surface is equal to the thickness of the inner core in the second direction; and / or, The number of inner cores is one or more, and when the number of inner cores is multiple, the multiple inner cores are arranged side by side along the second direction.

10. The battery cell according to claim 6, characterized in that, The battery cell is a square battery cell.

11. A method for assembling a battery cell, characterized in that, The assembly method, applied to the battery cell as described in any one of claims 6 to 10, comprises: Insert the inner core through the opening in the cell housing, allowing it to enter the second cavity; The top cover assembly is fitted into the opening of the cell housing; Laser welding is performed on the seam between the top cover assembly and the opening of the cell housing.

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