Top cover assembly and battery cell
By designing longitudinal and transverse arc surfaces on the lower insulation component of the top cover assembly, the problem of easy cracking of the insulation film connection when the battery cell vibrates is solved, thus improving the insulation and safety performance of the battery cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- AESC DYNAMICS TECHNOLOGY (ORDOS) LTD
- Filing Date
- 2025-06-25
- Publication Date
- 2026-06-23
Smart Images
Figure CN224400481U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of energy storage technology, and in particular to a top cover assembly 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 top cover assembly and a battery cell to at least partially solve the problem of low safety of battery cells.
[0004] Based on the above objectives, the first aspect of this application provides a top cover assembly, including a cover plate body and a lower insulating member connected to the cover plate body, characterized in that the lower insulating member includes an insulating body, the surface of the insulating body away from the cover plate body having a protrusion away from the cover plate body, and a longitudinal transition structure is formed between two adjacent sidewalls of the protrusion perpendicular to the cover plate body, at least one of the longitudinal transition structures being a longitudinal arc surface.
[0005] Based on the same inventive concept, a second aspect of this application also provides a battery cell, including a top cover assembly as described in the first aspect, and an insulating film forming a shell-like structure with an insulating open end; the insulating open end surrounds the sidewall of the lower insulating member; the insulating film is connected to the sidewall of the protrusion, and in the same protrusion, the longitudinal transition structure between the sidewall connected to the insulating film and the adjacent sidewall is a longitudinal arc surface.
[0006] Optionally, a transverse transition structure is formed between the sidewall of the protrusion perpendicular to the first direction and the surface of the protrusion away from the cover plate body, and at least one of the transverse transition structures is a transverse arc surface; the first direction, the thickness direction of the battery cell, and the height direction of the battery cell are perpendicular.
[0007] Optionally, the cross-sectional radius of the longitudinal arc surface is Rz, where 2mm ≤ Rz ≤ 15mm; and / or,
[0008] The cross-sectional radius of the horizontal arc surface is Rh, where 2mm ≤ Rh ≤ 15mm.
[0009] Optionally, the cover plate body is provided with an explosion-proof valve, the protrusion includes a venting protrusion and an exhaust protrusion corresponding to the explosion-proof valve, the venting protrusion and the exhaust protrusion are spaced apart along a first direction; the insulating body, the exhaust protrusion and the venting protrusion define a venting space; the exhaust protrusion is provided with an exhaust channel, the exhaust protrusion connects the venting space and the explosion-proof valve through the exhaust channel; the venting protrusion is provided with a venting channel, the venting channel passes through the venting protrusion along the first direction and communicates with the venting space; the transverse arc surface of the venting protrusion near the exhaust protrusion is the inner transverse arc surface, the transverse arc surface of the venting protrusion away from the exhaust protrusion is the outer transverse arc surface, the cross-sectional radius of the inner transverse arc surface is larger than the cross-sectional radius of the outer transverse arc surface.
[0010] Optionally, the insulating film is at least connected to the sidewall of the exhaust protrusion perpendicular to the thickness direction of the battery cell. The sidewall includes a planar region other than the longitudinal arc surface. The dimension of the planar region along the first direction is L0, and the thickness of the insulating film is T. When 0.1mm≤T<0.15mm, 15mm≤L0<40mm; when 0.15mm≤T≤0.35mm, 10mm≤L0≤25mm.
[0011] Optionally, the longitudinal arc surface of the exhaust protrusion is the exhaust longitudinal arc surface, and the longitudinal arc surface of the venting protrusion away from the exhaust protrusion is the venting outer longitudinal arc surface, wherein the cross-sectional radius of the exhaust longitudinal arc surface is greater than the cross-sectional radius of the venting outer longitudinal arc surface.
[0012] Optionally, the longitudinal arc surface of the venting protrusion near the exhaust protrusion is the inner longitudinal arc surface of the venting, and the cross-sectional radius of the inner longitudinal arc surface of the venting is smaller than the cross-sectional radius of the outer longitudinal arc surface of the venting.
[0013] Optionally, the battery cell includes an electrode assembly located on the side of the insulating body away from the cover plate body. The electrode assembly's tab is located between the exhaust protrusion and the venting protrusion. The longitudinal arc surface of the exhaust protrusion is an exhaust longitudinal arc surface, and the longitudinal arc surface of the venting protrusion near the exhaust protrusion is a venting inner longitudinal arc surface. The cross-sectional radius of the exhaust longitudinal arc surface is larger than the cross-sectional radius of the venting inner longitudinal arc surface.
[0014] Optionally, along the first direction, a ventilation protrusion is provided on each of the opposite sides of the exhaust protrusion.
[0015] As can be seen from the above, the top cover assembly and battery cell provided in this application design at least one longitudinal transition structure of the protrusion as a longitudinal arc surface. Since the longitudinal arc surface can extend at least from the bottom surface of the protrusion to the insulating body, that is, the longitudinal arc surface can cover the entire area of the protrusion along the height direction of the battery cell. Therefore, after the protrusion is formed, each area along the height direction of the battery cell has a part with good forming quality, resulting in high overall structural strength of the protrusion, improving the structural strength of the lower insulating component, enhancing the reliability of the top cover assembly, and also resisting the tensile force on each area connected to the insulating film, further reducing the risk of cracking of the protrusion due to vibration or impact of the electrode assembly on the insulating film. This allows the insulating film to form a reliable connection with the lower insulating component, which helps to improve the insulation performance and safety performance of the battery cell. 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 schematic diagram of a battery cell with the first structure according to an embodiment of this application;
[0018] Figure 2 This is a bottom view schematic diagram of the lower insulating member of the first structure according to an embodiment of this application;
[0019] Figure 3 This is a partial schematic diagram of the top cover assembly of the second structure according to an embodiment of this application;
[0020] Figure 4 This is a bottom view of the top cover assembly of the second structure according to an embodiment of this application;
[0021] Figure 5 This is a partial schematic diagram of a battery cell with a second structure according to an embodiment of this application;
[0022] Figure 6 This is a partial cross-sectional schematic diagram of a battery cell with the second structure according to an embodiment of this application;
[0023] Figure 7 This is a bottom view of the top cover assembly and related structural components of a battery cell with a second structure according to an embodiment of this application.
[0024] Figure 8 This is a side view of the top cover assembly of a battery cell with a second structure according to an embodiment of this application;
[0025] Figure 9 This is a partial cross-sectional schematic diagram of a battery cell with a third structure according to an embodiment of this application;
[0026] Figure 10 This is a bottom view of the top cover assembly and related structural components of a battery cell with a third structure according to an embodiment of this application.
[0027] Explanation of reference numerals in the attached figures:
[0028] 100. Insulating film; 110. Insulating open end;
[0029] 200. Lower insulating component; 210. Insulating body; 220. Protrusion; 221. Ventilation protrusion; 2211. Ventilation channel; 222. Exhaust protrusion; 2221. Exhaust outer wall; 2222. Exhaust channel; 223. Air guiding space; 230. Longitudinal transition structure; 240. Transverse transition structure; 250. Longitudinal arc surface; 251. Exhaust longitudinal arc surface; 252. Ventilation outer longitudinal arc surface; 253. Ventilation inner longitudinal arc surface; 260. Transverse arc surface; 261. Ventilation inner transverse arc surface; 262. Ventilation outer transverse arc surface;
[0030] 300. Content storage space;
[0031] 400. Electrode assembly; 410. Electrode tab; 420. Electrode body;
[0032] 500, Cover plate body; 600, Explosion-proof valve; 700, Electrode terminal; 800, Connecting part. Detailed Implementation
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] Figure 1 A partial cross-sectional schematic diagram of the battery cell of the first structure is shown.
[0039] by Figure 1 Taking the structure and orientation shown as an example, a battery cell may include a top cover assembly and an electrode assembly 400 disposed on one side of the top cover assembly. The electrode assembly 400 includes an electrode body 420 and tabs 410 extending from the electrode body 420. The top cover assembly includes a cover plate body 500, which is connected to electrode terminals 700 and an explosion-proof valve 600. The cover plate body 500 and the electrode terminals 700 can be connected by welding, gluing, riveting, etc., and the cover plate body 500 and the explosion-proof valve 600 can be connected by integral molding, welding, riveting, gluing, or fasteners. It should be noted that the number of electrode terminals 700 connected to the same cover plate body 500 is not limited, for example... Figure 1 The same cover body 500 in the battery cell is connected to two electrode terminals 700. The polarities of the two electrode terminals 700 can be the same (e.g., both electrode terminals 700 are positive terminals, or both are negative terminals) or not exactly the same (e.g., one of the two electrode terminals 700 is a positive terminal and the other is a negative terminal). Understandably, the same cover body 500 can also be connected to one electrode terminal 700. In this case, the battery cell includes two cover bodies 500, one of which is connected to a positive terminal, and the other is connected to a negative terminal and an explosion-proof valve 600.
[0040] Electrode terminals 700 are along the height direction of the battery cell (e.g.) Figure 1 The electrode terminal 700 (in the Z direction) penetrates the cover plate body 500. The end of the electrode terminal 700 away from the electrode assembly 400 is used to connect to an external circuit, and the end of the electrode terminal 700 close to the electrode assembly 400 is electrically connected to the corresponding tab 410.
[0041] like Figure 1 A lower insulating member 200 is connected to the surface of the cover plate body 500 near the electrode assembly 400. An insulating film 100 connected to the lower insulating member 200 covers the outer side of the electrode assembly 400. The insulating film 100 forms a shell-like structure and has an insulating opening end 110, which surrounds the sidewall of the lower insulating member 200. The shell-like structure means that the insulating film 100 forms a structure with an internal storage space 300, which can accommodate at least part of the electrode assembly 400. The insulating opening end 110 surrounding the sidewall of the lower insulating member 200 means that the insulating film 100 at the insulating opening end 110 can surround the insulating body 210 of the lower insulating member 200 or surround the protrusion 220. This is not limited here. Similarly, the insulating film 100 can be continuously arranged around the circumference of the lower insulating member 200 or several spaced portions can be arranged around the circumference of the lower insulating member. This is also not limited here. It should be noted that the number of insulating openings 110 is not limited, for example, it can be the same as the number of lower insulating members 200 provided in the battery cell. When the shell-like structure formed by the insulating film 100 is provided with two insulating openings 110, the two insulating openings 110 can be arranged opposite each other.
[0042] Although the lower insulating component 200 and the insulating film 100 help improve the insulation and safety performance of the battery cell, the applicant's research found that the battery cell may vibrate during transportation or use, which may cause the lower insulating component 200 to deform or crack, resulting in a decrease in the safety of the battery cell.
[0043] To avoid the aforementioned problems, the applicant studied the structure of the lower insulating element 200 in the top cover assembly.
[0044] Figure 2 A bottom view schematic diagram of the lower insulating member 200 of the first structure is shown.
[0045] like Figure 1 and Figure 2 The lower insulating member 200 includes an insulating body 210. A protrusion 220 is formed on the surface of the insulating body 210 away from the cover plate body 500 (hereinafter referred to as the bottom surface of the insulating body 210). The protrusion 220 has a sidewall perpendicular to the cover plate body 500, and the insulating film 100 is connected to this sidewall of the protrusion 220. A longitudinal transition structure 230 is formed between two adjacent sidewalls of the protrusion 220, and the longitudinal transition structure 230 has a right-angled edge.
[0046] The applicant discovered that if the longitudinal transition structure 230 has right-angled edges, the molten plastic will not flow smoothly at the right-angled edges during injection molding of the lower insulating part 200. This makes the portion of the protrusion 220 near the right-angled edges prone to cooling cavities and uneven filling, resulting in lower overall structural strength of the protrusion 220. When the insulating film 100 connected to the protrusion 220 transmits the tensile force it receives to the protrusion 220, the protrusion 220 with lower structural strength will be prone to cracking.
[0047] To solve the above problems, at least one vertical transition structure 230 can be designed as a rounded corner structure.
[0048] Figure 3 A partial schematic diagram of the top cover assembly with the second structure is shown. Figure 4 A bottom-view schematic diagram of the top cover assembly of the second structure is shown.
[0049] like Figure 3 and Figure 4 In some embodiments, the top cover assembly includes a cover body 500 and a lower insulating member 200 connected to the cover body 500. The lower insulating member 200 includes an insulating body 210. The surface of the insulating body 210 away from the cover body 500 has a protrusion 220 that is away from the cover body 500. A longitudinal transition structure 230 is formed between two adjacent sidewalls of the protrusion 220 that are perpendicular to the cover body 500. At least one longitudinal transition structure 230 is a longitudinal arc surface 250.
[0050] For example, the lower insulating element 200 can be formed by injection molding.
[0051] For example, the lower insulating member 200 and the cover plate body 500 can be connected by means of adhesive, heat pressing, snap-fit or fastener connection.
[0052] For example, the insulating body 210 can be a plate-like structure, and the plate-like structure can be provided with recessed structures, holes or protruding structures, etc.
[0053] For example, the protrusion 220 may be disposed in the middle of the bottom surface of the insulating body 210 and / or disposed in the length direction of the insulating body 210 (e.g., Figure 4 The end of (in the X direction).
[0054] For example, along the height direction of the battery cell, the shape of the orthographic projection of the protrusion 220 onto the bottom surface of the insulating body 210 can be a rectangle, and at least one apex corner of the rectangle is rounded; or, the shape of the projection can also be a polygon other than a rectangle, and similarly, at least one apex corner of the polygon is rounded.
[0055] For example, for the same longitudinal transition structure 230, along its extension direction (i.e., Figure 3(In the Z direction), the entire area of the longitudinal transition structure 230 is a longitudinal circular arc surface 250, or only a part of the area may be a longitudinal circular arc surface 250.
[0056] It should be noted that when a portion of the sidewall of the protrusion 220 is coplanar with the sidewall of the insulating body 210 on the same side, and the longitudinal transition structure 230 adjacent to the sidewall of the protrusion 220 is provided with a longitudinal arc surface 250, the longitudinal arc surface 250 can extend from the protrusion 220 to the insulating body 210. When the sidewall of the protrusion 220 is not coplanar with the sidewall of the insulating body 210 on the same side, and the longitudinal transition structure 230 adjacent to the sidewall of the protrusion 220 is provided with a longitudinal arc surface 250, the longitudinal arc surface 250 extends from the bottom surface of the insulating body 210 to the surface of the protrusion 220 away from the insulating body 210 (hereinafter referred to as the bottom surface of the protrusion 220).
[0057] Understandably, when filling a mold, the flow of molten plastic is smoother at rounded corners than at right angles. The smoother the flow, the lower the risk of defects such as porosity or uneven filling, resulting in higher molding quality. However, the effect of rounded corners on the flow of molten plastic is limited, such as... Figure 3 If only the bottom edge of the protrusion 220 is rounded, then under the influence of the rounded corner, the part of the protrusion 220 near the bottom surface has a higher forming quality, while the part far from the bottom surface (i.e., the part near the insulating body 210) has a relatively lower forming quality.
[0058] The applicant's research also found that when a battery cell vibrates, the electrode assembly 400 may move relative to the insulating film 100, or tend to move relative to the insulating film 100. In this situation, the electrode assembly 400 exerts a significant tensile force on the insulating film 100, which is then transmitted to the lower insulating member 200. This could cause cracking at the connection between the lower insulating member 200 and the insulating film 100, leading to connection failure between the lower insulating member 200 and the insulating film 100, thus adversely affecting the safety of the battery cell.
[0059] Reference Figure 1 The insulating film 100 is connected to the sidewall of the protrusion 220, and the part where the two connect is called the connecting part 800. To improve the reliability of the connecting part 800, it has a certain dimension in the height direction of the battery cell. When the insulating film 100 transmits tensile force to the protrusion 220, the entire area of the connecting part 800 will be under stress. Although the part of the protrusion 220 near the bottom surface is not prone to cracking, the part near the insulating body 210 may still crack.
[0060] In view of the above, in this embodiment, at least one longitudinal transition structure 230 of the protrusion 220 is designed as a longitudinal arc surface 250. Since the longitudinal arc surface 250 can extend from the bottom surface of the protrusion 220 to the insulating body 210, that is, the longitudinal arc surface 250 can cover the entire area of the protrusion 220 along the height direction of the battery cell. Therefore, after the protrusion 220 is formed, each area along the height direction of the battery cell has a part with good forming quality, which makes the overall structural strength of the protrusion 220 high. It can resist the tensile force on each area of the connection part 800, and further reduce the risk of cracking of the connection part 800 of the protrusion 220 due to the vibration or impact of the electrode assembly 400 on the insulating film 100. This allows the insulating film 100 to form a reliable connection with the lower insulating member 200, which helps to improve the insulation performance and safety performance of the battery cell.
[0061] Based on the same inventive concept and in conjunction with the description of the top cover assembly in the above embodiments, this embodiment provides a battery cell that has the corresponding technical effects of the top cover assembly in the above embodiments, which will not be repeated here.
[0062] Figure 5 A partial schematic diagram of a battery cell with the second structure is shown; Figure 6 A partial cross-sectional schematic diagram of a battery cell with the second structure is shown; Figure 7 A bottom view schematic diagram showing the top cover assembly and related structural components of the battery cell with the second structure is shown.
[0063] like Figure 5 , Figure 6 and Figure 7 A battery cell includes a top cover assembly as described in the above embodiment, and also includes an insulating film 100 forming a shell-like structure and having an insulating opening end 110; the insulating opening end 110 surrounds the sidewall of the lower insulating member 200; the insulating film 100 is connected to the sidewall of the protrusion 220, and in the same protrusion 220, the longitudinal transition structure 230 between the sidewall connected to the insulating film 100 and the adjacent sidewall is a longitudinal arc surface 250.
[0064] For example, the insulating film 100 and the lower insulating member 200 can be connected by means of heat melting, adhesive bonding or snap-fitting.
[0065] by Figure 7 The structure and orientation shown are used as examples for explanation. Figure 7 The rightmost protrusion 220 has a sidewall including the right sidewall ( Figure 7 Shown as the right straight edge of the protrusion 220), the upper sidewall ( Figure 7 Shown as the upper straight edge of the protrusion 220), and the lower sidewall ( Figure 7 Shown as the lower straight edge of the protrusion 220) and the left sidewall ( Figure 7 (Shown as the left straight edge of the protrusion 220).
[0066] Of the four sidewalls mentioned above, only the right sidewall may be connected to the insulating film 100. In this case, the longitudinal transition structure 230 between the right sidewall and the upper sidewall is a longitudinal arc surface 250, and the longitudinal transition structure 230 between the right sidewall and the lower sidewall is a longitudinal arc surface 250, while the longitudinal transition structure 230 between the left sidewall and the upper sidewall and the longitudinal transition structure 230 between the left sidewall and the lower sidewall may not be a longitudinal arc surface 250.
[0067] Of the four sidewalls mentioned above, the right, top, and bottom sidewalls may all be connected to the insulating film 100. In this case, all four longitudinal transition structures 230 are longitudinal arc surfaces 250.
[0068] Understandably, when the insulating film 100 transmits tensile force to the protrusion 220, the sidewall of the protrusion 220 connected to the insulating film 100 experiences a large tensile force and is more prone to cracking under this force. To prevent the protrusion 220 from cracking, this embodiment prioritizes designing the longitudinal transition structure 230 between the sidewall of the protrusion 220 connected to the insulating film 100 and the adjacent sidewall as a longitudinal arc surface 250. This significantly improves the structural strength of the sidewall of the protrusion 220 connected to the insulating film 100, reducing the risk of cracking. This allows the insulating film 100 to form a reliable connection with the lower insulating component 200, contributing to improved insulation and safety performance of the battery cell.
[0069] Figure 8 A side view of the top cover assembly of the second type of battery cell is shown.
[0070] like Figure 7 and Figure 8 In some embodiments, the protrusion 220 is perpendicular to a first direction (the first direction is as follows). Figure 7 A transverse transition structure 240 is formed between the sidewall (in the X direction) and the bottom surface of the protrusion 220, and at least one transverse transition structure 240 is a transverse arc surface 260; the first direction, the thickness direction of the battery cell and the height direction of the battery cell are perpendicular.
[0071] by Figure 7 The structure and orientation shown are used as examples for explanation. Figure 7 The rightmost protrusion 220 has a sidewall perpendicular to the first direction, which is the right sidewall and the left sidewall of the protrusion 220.
[0072] For example, when a portion of the transverse transition structure 240 within the same protrusion 220 is a transverse arc surface 260, the transverse transition structure 240 closest to the insulating film 100 is preferably designed as a transverse arc surface 260. Combined with Figure 7 , Figure 8 As can be seen from the foregoing, for Figure 7 and Figure 8 The rightmost protrusion 220 has a horizontal transition structure 240 on its left side that is far from the insulating film 100, while its right side has a horizontal transition structure 240 that is close to the insulating film 100. Therefore, the right horizontal transition structure 240 is preferably designed as a horizontal arc surface 260, while the left horizontal transition structure 240 does not need to have a horizontal arc surface 260.
[0073] For example, for the same horizontal transition structure 240, along its extension direction, the entire area of the horizontal transition structure 240 can be designed as a horizontal arc surface 260, or a portion of the horizontal transition structure 240 can be designed as a horizontal arc surface 260.
[0074] Understandably, designing the transverse transition structure 240 as a transverse arc surface 260 can at least improve the forming quality of the protrusions 220 in the vicinity of the transverse arc surface 260, which helps to improve the structural strength of the protrusions 220 and further reduces the risk of the protrusions 220 cracking after being subjected to tensile force transmitted from the insulating film 100. This allows the insulating film 100 to form a reliable connection with the lower insulating member 200, which helps to improve the insulation performance and safety performance of the battery cell.
[0075] Meanwhile, since the insulating film 100 is connected to the sidewall of the protrusion 220, if all the transverse transition structures 240 are sharp right angles, they may cut the insulating film 100 when they come into contact with it. However, when the transverse transition structure 240 is a horizontal arc surface 260, the insulating film 100 no longer comes into contact with sharp right angles, but with the smooth horizontal arc surface 260. This effectively reduces the risk of the insulating film 100 being cut and helps to improve the insulation and safety performance of the battery cell.
[0076] like Figure 7 and Figure 8 In some embodiments, the cross-sectional radius of the longitudinal arc surface 250 is Rz, where 2mm≤Rz≤15mm.
[0077] For example, Rz can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or 15mm.
[0078] Understandably, when the insulating film 100 is connected to the sidewall of the protrusion 220, only the flat surface area on the sidewall can effectively connect with the insulating film 100. Neither the location of the horizontal arc surface 260 nor the location of the vertical arc surface 250 can achieve an effective connection with the insulating film 100. Therefore, if Rz is too large, the vertical arc surface 250 will encroach on the space of the flat surface on the sidewall, resulting in a small effective connection area between the insulating film 100 and the sidewall of the protrusion 220, and consequently, a weak connection strength. If Rz is too small, the effect of improving the molding quality of the protrusion 220 by setting the vertical arc surface 250 is not significant, and the risk of cracking in the protrusion 220 remains relatively high.
[0079] To avoid the above problems, in this embodiment, Rz is designed to be 2mm≤Rz≤15mm. On the one hand, this can effectively improve the molding quality of the protrusion 220 and increase the structural strength of the protrusion 220 to reduce the risk of cracking of the protrusion 220. On the other hand, it can ensure that a large effective connection area can be formed between the side wall of the protrusion 220 and the insulating film 100, ensuring that the connection between the insulating film 100 and the protrusion 220 is reliable.
[0080] like Figure 7 and Figure 8 In some embodiments, the cross-sectional radius of the horizontal arc surface 260 is Rh, where 2mm≤Rh≤15mm.
[0081] For example, Rh can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or 15mm.
[0082] The problems caused by excessively large or small Rh are similar to those caused by excessively large or small Rz, and will not be repeated here. Similarly, the beneficial effects of designing Rh to 2mm≤Rh≤15mm in this embodiment are similar to the beneficial effects of designing Rz to 2mm≤Rz≤15mm, and will not be repeated here.
[0083] Figure 9 A partial cross-sectional diagram of a battery cell with the third structure is shown. Figure 10 A bottom-view schematic diagram showing the top cover assembly and related structural components of the battery cell with the third structure is displayed.
[0084] like Figure 9 and Figure 10In some embodiments, the cover body 500 is provided with an explosion-proof valve 600, and the protrusion 220 includes a venting protrusion 221 and an exhaust protrusion 222 corresponding to the explosion-proof valve 600. The venting protrusion 221 and the exhaust protrusion 222 are spaced apart along a first direction. The insulating body 210, the exhaust protrusion 222, and the venting protrusion 221 together define a venting space 223. The exhaust protrusion 222 is provided with an exhaust channel 2222, and the exhaust protrusion 222 connects the venting space 223 and the exhaust channel 2222. An explosion-proof valve 600; a venting protrusion 221 is provided with a venting channel 2211, which runs through the venting protrusion 221 in a first direction and is connected to the air guiding space 223; the transverse arc surface 260 of the venting protrusion 221 near the exhaust protrusion 222 is the inner transverse arc surface 261, and the transverse arc surface 260 of the venting protrusion 221 away from the exhaust protrusion 222 is the outer transverse arc surface 262, and the cross-sectional radius of the inner transverse arc surface 261 is larger than the cross-sectional radius of the outer transverse arc surface 262.
[0085] For example, when at least two electrode terminals 700 are connected to the same cover plate body 500, the at least two electrode terminals 700 may be spaced apart on opposite sides of the explosion-proof valve 600 along a first direction. When one electrode terminal 700 is connected to the same cover plate body 500, the electrode terminal 700 is spaced apart from the explosion-proof valve 600 along the first direction.
[0086] During normal charging and discharging, gas is generated inside the battery cell. As the gas flows inside the battery cell, it can enter the venting channel 2211 through the opening away from the exhaust protrusion 222 (hereinafter referred to as the inlet of the venting channel 2211) and enter the venting space 223 through the opening near the exhaust protrusion 222 (hereinafter referred to as the outlet of the venting channel 2211). If the transverse transition structure 240 near the inlet of the venting channel 2211 is a right-angled edge, some gas will not be able to flow smoothly into the venting channel 2211 through the right-angled edge, thus obstructing the gas from entering the venting channel 2211 and causing the gas to accumulate near the inlet of the venting channel 2211. The accumulated gas exerts a force on the insulating film 100 near the inlet of the venting channel 2211, pulling the insulating film 100 towards the outlet of the venting channel 2211 and causing partial or complete detachment of the connection between the insulating film 100 and the protrusion 220, resulting in connection failure and negatively impacting the safety of the battery cell. Furthermore, when this force is transmitted to the connection portion 800, the insulating film 100 or the protrusion 220 may rupture at the connection portion 800, leading to a weak connection or even detachment between the protrusion 220 and the insulating film 100. The applicant's research has found that when the transverse transition structure 240 at the outlet of the venting channel 2211 is at a right angle, gas will also accumulate near the outlet of the venting channel 2211, causing poor gas flow inside the battery cell and resulting in vibration of the lower insulating component 200, which is detrimental to the structural stability inside the battery cell.
[0087] To avoid the above problems, the two transverse transition structures 240 of the venting protrusion 221 can be designed as an inner transverse arc surface 261 and an outer transverse arc surface 262, respectively, so that the gas can smoothly enter the inlet of the venting channel 2211 and flow out from the outlet of the venting channel 2211, preventing the gas from accumulating near the venting channel 2211, reducing the pulling force on the insulating film 100 when the gas flows, ensuring that the insulating film 100 can be reliably connected to the protrusion 220, and helping to improve the insulation performance and safety performance of the battery cell.
[0088] Meanwhile, the cross-sectional radius of the inner transverse arc surface 261 of the ventilation system is larger than that of the outer transverse arc surface 262 of the ventilation system, which allows the inner transverse arc surface 261 of the ventilation system to extend to the outlet of the ventilation channel 2211, such as... Figure 9 At this point, compared to the inlet of the ventilation channel 2211, the outlet of the ventilation channel 2211 has a larger portion located on the corresponding side of the inner transverse arc surface 261, meaning that the cross-sectional area at the outlet is relatively larger than that at the inlet. For example... Figure 9In some embodiments, the inlet of the ventilation channel 2211 is located on a vertical plane, while a portion of the outlet of the ventilation channel 2211 is located on a curved surface, making the outlet area of the ventilation channel 2211 larger than the inlet area. This can increase the gas velocity when passing through the outlet of the ventilation channel 2211 and help improve the exhaust efficiency of the ventilation channel 2211.
[0089] like Figure 9 and Figure 10 In some embodiments, the insulating film 100 is at least connected to the sidewall of the venting protrusion 222 perpendicular to the thickness direction of the battery cell (hereinafter referred to as the venting sidewall 2221). The venting sidewall 2221 includes a planar region other than the longitudinal arc surface 250. The dimension of the planar region along the first direction is L0, and the thickness of the insulating film 100 is T. When 0.1mm≤T<0.15mm, 15mm≤L0<40mm; when 0.15mm≤T≤0.35mm, 10mm≤L0≤25mm.
[0090] It should be noted that the thickness of the insulating film 100 is the thickness of a single layer of the insulating film 100.
[0091] For example, the exhaust outer sidewall 2221 is coplanar with the sidewall of the insulating body 210 on the same side.
[0092] For example, when 0.1mm ≤ T < 0.15mm, L0 can be 15mm, 20mm, 25mm, 30mm, 35mm or 40mm.
[0093] For example, when 0.15mm≤T≤0.35mm, L0 can be 10mm, 13mm, 15mm, 18mm, 20mm, 23mm or 25mm.
[0094] As described above, when the insulating film 100 is connected to the outer wall 2221 of the exhaust protrusion 222, the insulating film 100 can form an effective connection with the planar area on the outer wall 2221. Understandably, a larger connection portion 800 can improve connection reliability, and increasing the size of the area on the exhaust protrusion 222 available for the insulating film 100 to connect with can provide the conditions for setting a larger connection portion 800. Therefore, the size of L0 needs to be designed to ensure sufficient effective connection area between the exhaust protrusion 222 and the insulating film 100. However, given that the overall size of the lower insulating member 200 is relatively fixed, if L0 is too large, it will encroach on the space of the longitudinal arc surface 250 of the exhaust protrusion 222, adversely affecting the molding quality of the exhaust protrusion 222. If L0 is too small, the area available for effective connection between the exhaust protrusion 222 and the insulating film 100 will be too small, that is, the area forming the connection portion 800 will be too small, adversely affecting the connection strength between the two.
[0095] Meanwhile, the applicant also discovered that in some embodiments, the thickness of the insulating film 100 in the battery cell varies. For the same size connecting portion 800, the connection strength between the insulating film 100 of different thicknesses and the lower insulating member 200 also varies; generally, the thinner the insulating film 100, the weaker its connection strength. Therefore, in order to meet the connection strength requirements between the exhaust protrusion 222 and the insulating film 100, different connection areas need to be designed for insulating films 100 of different thicknesses, i.e., different L0 values are required. Specifically, for insulating films 100 with a smaller thickness, a larger L0 is generally required; while for insulating films 100 with a larger thickness, L0 can be set relatively smaller.
[0096] Considering the aforementioned factors, in this embodiment, L0 is designed such that when 0.1mm ≤ T < 0.15mm, 15mm ≤ L0 < 40mm; and when 0.15mm ≤ T ≤ 0.35mm, 10mm ≤ L0 ≤ 25mm. When L0 meets the above design requirements, on the one hand, it ensures that the connection strength between the insulating film 100 and the venting protrusion 222 meets the process requirements, ensuring a reliable connection between the insulating film 100 and the venting protrusion 222. On the other hand, it also allows for the provision of space for a longitudinal arc surface 250 on the venting protrusion 222. This allows for the improvement of the molding quality and structural strength of the venting protrusion 222 by providing the longitudinal arc surface 250, preventing cracking at the connection point between the venting protrusion 222 and the insulating film 100, further ensuring a reliable connection between the insulating film 100 and the venting protrusion 222.
[0097] like Figure 9 and Figure 10 In some embodiments, the longitudinal arc surface 250 of the exhaust protrusion 222 is the exhaust longitudinal arc surface 251, and the longitudinal arc surface 250 of the ventilation protrusion 221 away from the exhaust protrusion 222 is the ventilation outer longitudinal arc surface 252. The cross-sectional radius of the exhaust longitudinal arc surface 251 is larger than the cross-sectional radius of the ventilation outer longitudinal arc surface 252.
[0098] The exhaust protrusion 222 corresponds to the explosion-proof valve 600. When a battery cell experiences thermal runaway, the high-temperature gas inside the battery cell carries particulate matter (hereinafter referred to as emissions) into the exhaust channel 2222, and is discharged through the explosion-proof valve 600 after flowing through the exhaust channel 2222. Part of the emissions entering the exhaust channel 2222 flow sequentially through the venting channel 2211 and the venting space 223, while another part enters the exhaust channel 2222 directly from the venting space 223. In other words, the total amount of emissions flowing through the exhaust channel 2222 is greater than the total amount flowing through a single venting channel 2211. Compared to the venting channel 2211, the exhaust channel 2222 is subject to more thermal impact from the emissions. This requires the exhaust protrusion 222 to have a greater structural strength than the venting protrusion 221 to prevent deformation of the exhaust protrusion 222 during thermal runaway of the battery cell and reduce the risk of blockage in the exhaust channel 2222.
[0099] As can be seen from the foregoing, the larger the cross-sectional radius of the longitudinal arc surface 250, the better the forming quality and the higher the structural strength of the protrusion 220. Therefore, in this embodiment, designing the cross-sectional radius of the exhaust longitudinal arc surface 251 to be larger than the cross-sectional radius of the venting outer longitudinal arc surface 252 can give the exhaust protrusion 222 higher forming quality and structural strength, further reducing the risk of deformation and failure of the exhaust protrusion 222 when the battery cell experiences thermal runaway, which is beneficial to improving the safety performance of the battery cell.
[0100] like Figure 9 and Figure 10 In some embodiments, the longitudinal arc surface 250 of the vent protrusion 221 near the exhaust protrusion 222 is the inner longitudinal arc surface 253 of the vent, and the cross-sectional radius of the inner longitudinal arc surface 253 of the vent is smaller than the cross-sectional radius of the outer longitudinal arc surface 252 of the vent.
[0101] by Figure 10 The structure and orientation shown are used as examples for explanation. Figure 10The rightmost ventilation protrusion 221 has its upper, right, and lower sidewalls connected to the insulating film 100, while its left sidewall is not connected. This means that in this ventilation protrusion 221, only one of the two sidewalls adjacent to the inner longitudinal arc surface 253 (i.e., the left and upper sidewalls; or the left and lower sidewalls) is connected to the insulating film 100, while both sidewalls adjacent to the outer longitudinal arc surface 252 (i.e., the right and upper sidewalls; or the right and lower sidewalls) are connected to the insulating film 100. This requires that the structural strength of the portion of the ventilation protrusion 221 near the outer longitudinal arc surface 252 be higher than that of the portion near the inner longitudinal arc surface 253. Therefore, in this embodiment, the cross-sectional radius of the outer longitudinal arc surface 252 is designed to be larger, so that the forming quality and structural strength of the portion of the ventilation protrusion 221 near the outer longitudinal arc surface 252 are higher.
[0102] It should also be noted that if the cross-sectional radii of both the inner longitudinal arc surface 253 and the outer longitudinal arc surface 252 of the vent are designed to be large, it will lead to... Figure 10 The flat areas of the upper and lower sidewalls of the rightmost vent protrusion 221 are relatively small, which is not conducive to the reliable connection between the insulating film 100 and the vent protrusion 221. Therefore, in this embodiment, the cross-sectional radius of the inner longitudinal arc surface 253 of the vent is preferably designed to be small.
[0103] Furthermore, as can be seen from the foregoing, the cross-sectional radius of the inner transverse arc surface 261 of the vent is larger than that of the outer transverse arc surface 262 of the vent, which is closer to the inner longitudinal arc surface 253 of the vent. Therefore, designing the vent protrusion 221 such that the cross-sectional radius of the inner longitudinal arc surface 253 of the vent is smaller than that of the outer longitudinal arc surface 252 of the vent can make the structural strength of the vent protrusion 221 more uniform and further prevent the vent protrusion 221 from cracking.
[0104] like Figure 9 and Figure 10 In some embodiments, the battery cell includes an electrode assembly 400, which is located on the side of the insulating body 210 away from the cover body 500. The tab 410 of the electrode assembly 400 is located between the exhaust protrusion 222 and the venting protrusion 221. The longitudinal arc surface 250 of the exhaust protrusion 222 is the exhaust longitudinal arc surface 251, and the longitudinal arc surface 250 of the venting protrusion 221 near the exhaust protrusion 222 is the venting inner longitudinal arc surface 253. The cross-sectional radius of the exhaust longitudinal arc surface 251 is larger than the cross-sectional radius of the venting inner longitudinal arc surface 253.
[0105] For example, two tabs 410 may be provided at intervals along the thickness direction of the battery cell between the exhaust protrusion 222 and the vent protrusion 221. The two tabs 410 have the same polarity and are electrically connected to the same electrode terminal 700.
[0106] For example, tab 410 can be directly electrically connected to electrode terminal 700, or electrically connected to electrode terminal 700 via an adapter.
[0107] For example, each tab 410 includes multiple layers of sheet foil tightly stacked along the height direction of the battery cell.
[0108] For large-sized battery cells, to meet the requirements of current carrying capacity and energy efficiency, the dimension of the tab 410 along the first direction (hereinafter referred to as the width of the tab 410) is relatively large. Meanwhile, the electrode body 420 includes stacked electrode sheets, and the tab 410 is disposed on the electrode sheets. That is, the tab 410 can also be a stacked structure. However, misalignment may occur between the stacked tabs 410 along the first direction, which will cause the actual space occupied by the tab 410 along the first direction to be larger than the designed size. All of the above factors may cause interference between the tab 410 and the protrusions 220 (including the venting protrusion 222 and the ventilation protrusion 221).
[0109] The applicant's research found that the width of the end of the tab 410 connected to the electrode terminal 700 is smaller, while the width of the end connected to the electrode body 420 (hereinafter referred to as the root of the tab 410) is larger. Therefore, if the tab 410 interferes with the protrusion 220, it is more likely that the part of the tab 410 near the root will interfere with the longitudinal transition structure 230 of the protrusion 220.
[0110] To solve the above problems, an exhaust longitudinal arc surface 251 can be provided on the exhaust protrusion 222, and an inner longitudinal arc surface 253 can be provided on the ventilation protrusion 221 to increase the distance between the protrusion 220 and the root of the tab 410, thereby reducing the risk of interference between the tab 410 and the protrusion 220.
[0111] Furthermore, during use, heat is generated on the tab 410 of the battery cell, causing the internal temperature of the battery cell to rise. Combined with... Figure 10As can be seen, in some embodiments, tabs 410 are provided on both sides of the venting protrusion 222 along the first direction, while tabs 410 are provided on only one side of the venting protrusion 221. Therefore, compared with the venting protrusion 221, the venting protrusion 222 is more affected by the heat generated by the tabs 410. To address this, in this embodiment, the cross-sectional radius of the venting longitudinal arc surface 251 is designed to be larger than the cross-sectional radius of the venting inner longitudinal arc surface 253. This not only further reduces the risk of interference between the tabs 410 and the venting protrusion 222, but also effectively prevents the tabs 410 from deforming during battery cell assembly and use. Furthermore, it ensures that the venting protrusion 222 retains a certain structural strength when affected by heat, thus contributing to improving the safety performance of the battery cell.
[0112] like Figure 9 and Figure 10 In some embodiments, along the first direction, a ventilation protrusion 221 is provided on each of the opposite sides of the exhaust protrusion 222.
[0113] Since each venting protrusion 221 can be connected to the insulating film 100, setting two venting protrusions 221 can increase the connection area between the lower insulating component 200 and the insulating film 100, improve the connection strength between the two, ensure that the two can achieve a reliable connection, and help improve the insulation performance and safety performance of the battery cell.
[0114] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.
[0115] 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.
[0116] 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.
[0117] 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.
[0118] 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.
[0119] 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 top cover assembly, comprising a cover plate body and a lower insulating member connected to the cover plate body, characterized in that, The lower insulating member includes an insulating body, on the surface of the insulating body away from the cover plate body, a protrusion is formed away from the cover plate body, and a longitudinal transition structure is formed between two adjacent sidewalls of the protrusion perpendicular to the cover plate body, at least one of the longitudinal transition structures being a longitudinal arc surface.
2. A battery cell, comprising the top cover assembly as described in claim 1, characterized in that: It also includes an insulating film forming a shell-like structure and having an insulating open end; the insulating open end surrounds the sidewall of the lower insulating member; the insulating film is connected to the sidewall of the protrusion, and in the same protrusion, the longitudinal transition structure between the sidewall connected to the insulating film and the adjacent sidewall is a longitudinal arc surface.
3. The battery cell according to claim 2, characterized in that, A transverse transition structure is formed between the sidewall of the protrusion perpendicular to the first direction and the surface of the protrusion away from the cover plate body, and at least one of the transverse transition structures is a transverse arc surface; the first direction, the thickness direction of the battery cell, and the height direction of the battery cell are perpendicular.
4. The battery cell according to claim 3, characterized in that, The radius of the cross-section of the longitudinal circular arc surface is Rz, where 2mm ≤ Rz ≤ 15mm; and / or, The cross-sectional radius of the horizontal arc surface is Rh, where 2mm ≤ Rh ≤ 15mm.
5. The battery cell according to claim 2, characterized in that, The cover plate body is provided with an explosion-proof valve, and the protrusion includes a venting protrusion and an exhaust protrusion corresponding to the explosion-proof valve. The venting protrusion and the exhaust protrusion are spaced apart along a first direction. The insulating body, the exhaust protrusion, and the venting protrusion define a venting space; the exhaust protrusion is provided with an exhaust channel, and the exhaust protrusion connects to the venting space and the explosion-proof valve through the exhaust channel; the venting protrusion is provided with a venting channel, and the venting channel passes through the venting protrusion along the first direction and communicates with the venting space. The horizontal arc surface of the venting protrusion that is close to the exhaust protrusion is the inner horizontal arc surface of the venting protrusion, and the horizontal arc surface of the venting protrusion that is away from the exhaust protrusion is the outer horizontal arc surface of the venting protrusion. The cross-sectional radius of the inner horizontal arc surface of the venting protrusion is greater than the cross-sectional radius of the outer horizontal arc surface of the venting protrusion.
6. The battery cell according to claim 5, characterized in that, The insulating film is at least connected to the sidewall of the exhaust protrusion perpendicular to the thickness direction of the battery cell. The sidewall includes a planar region other than the longitudinal arc surface. The dimension of the planar region along the first direction is L0, and the thickness of the insulating film is T. When 0.1mm≤T<0.15mm, 15mm≤L0<40mm; When 0.15mm≤T≤0.35mm, 10mm≤L0≤25mm.
7. The battery cell according to claim 5, characterized in that, The longitudinal arc surface of the exhaust protrusion is the exhaust longitudinal arc surface, and the longitudinal arc surface of the venting protrusion away from the exhaust protrusion is the venting outer longitudinal arc surface. The cross-sectional radius of the exhaust longitudinal arc surface is larger than the cross-sectional radius of the venting outer longitudinal arc surface.
8. The battery cell according to claim 7, characterized in that, The longitudinal arc surface of the venting protrusion near the exhaust protrusion is the inner longitudinal arc surface of the venting, and the cross-sectional radius of the inner longitudinal arc surface of the venting is smaller than the cross-sectional radius of the outer longitudinal arc surface of the venting.
9. The battery cell according to claim 5, characterized in that, The battery cell includes an electrode assembly located on the side of the insulating body away from the cover plate body. The electrode tab of the electrode assembly is located between the exhaust protrusion and the venting protrusion. The longitudinal arc surface of the exhaust protrusion is an exhaust longitudinal arc surface, and the longitudinal arc surface of the venting protrusion near the exhaust protrusion is a venting inner longitudinal arc surface. The cross-sectional radius of the exhaust longitudinal arc surface is larger than the cross-sectional radius of the venting inner longitudinal arc surface.
10. The battery cell according to claim 5, characterized in that, Along the first direction, a ventilation protrusion is provided on each of the opposite sides of the exhaust protrusion.