Battery cell and battery pack

Abstract

The application relates to an electric core and a battery pack, and relates to the technical field of batteries. The electric core comprises a pole group, an insulating film and a first adhesive member. The insulating film is provided with an adhesive window. Part of the outer wall of the pole group is exposed through the adhesive window. The first adhesive member adheres the insulating film and the exposed outer wall of the pole group through the adhesive window. The insulating film comprises a first covering surface and a second covering surface. The first covering surface is provided with a first through hole, and the second covering surface is provided with a second through hole. The first through hole and the second through hole form the adhesive window in the state that the insulating film covers the outer wall of the pole group. The adhesive overlap length of the first adhesive member and the first covering surface in the first direction is C1, and C1 satisfies 3mm<=C1<=50mm. And / or, the adhesive overlap length of the first adhesive member and the second covering surface in the first direction is C2, and C2 satisfies 3mm<=C2<=50mm. The electric core and the battery pack can realize stable fixation between the insulating film and the pole group without introducing a hot melting process.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery cell and a battery pack. Background Technology

[0002] In battery manufacturing, after assembly, the electrode assembly needs to be housed in a metal casing. To prevent the inner wall of the casing from scratching the electrode assembly during installation, an insulating film is usually used to cover the outer wall of the electrode assembly, thus protecting it from scratches.

[0003] In related technologies, the use of a hot-melt process to fix the insulating film increases manufacturing costs and process complexity. If hot-melt fixing is abandoned and the insulating film is relied upon entirely for its own wrapping, there is a risk that the insulating film may shift or even fall off during the electrode assembly insertion process, affecting assembly reliability and efficiency.

[0004] Therefore, how to achieve stable fixation between the insulating film and the electrode assembly without introducing a hot-melt process has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, embodiments of this application provide a battery cell and battery pack that can achieve stable fixation between the insulating film and the electrode assembly without introducing a hot-melt process.

[0006] The battery cell and battery pack provided in this application embodiment, in a first aspect, directly bond the electrode assembly body to the bonding window of the insulating film using a first adhesive member, thereby achieving relative fixation between the insulating film and the electrode assembly, avoiding the use of a hot-melt process, and thus eliminating the problems caused by the hot-melt process (complex process and high manufacturing cost). Furthermore, compared to a structure where the insulating film is simply wrapped around the electrode assembly without any fixation, the first adhesive member in this application embodiment can bond and fix the insulating film and the electrode assembly, reducing the risk of displacement or even detachment of the insulating film during the electrode assembly insertion process, ensuring the assembly reliability between the electrode assembly and the housing, and improving assembly efficiency. Secondly, by limiting the bonding overlap length between the first adhesive and the first covering surface along the first direction to C1, and the bonding overlap length between the first adhesive and the second covering surface along the first direction to C2, C1 and C2 satisfy: 3mm≤C1≤50mm; 3mm≤C2≤50mm, it ensures that the first adhesive has a sufficiently long portion to be bonded to the insulating film, guaranteeing the bonding reliability between the first adhesive and the insulating film. At the same time, while ensuring sufficient strength, it avoids the overuse of the first adhesive, saving material costs, and preventing other problems that may be caused by the first adhesive being too long, such as affecting heat dissipation efficiency. Attached Figure Description

[0007] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0008] Figure 1 A schematic diagram of the structure of a battery cell provided in an exemplary embodiment of this application from a first-view perspective.

[0009] Figure 2 This is a schematic diagram of the structure of a battery cell after the first adhesive component has been removed, as provided in an exemplary embodiment of this application.

[0010] Figure 3 This is a schematic diagram of the structure of a pole group provided for an exemplary embodiment of this application.

[0011] Figure 4 This is a schematic diagram of the structure of an insulating film in its unfolded state, provided as an exemplary embodiment of this application.

[0012] Figure 5 This application provides a schematic diagram of the structure of the insulating film in the covered state as an exemplary embodiment of the present application.

[0013] Figure 6 A schematic diagram of the structure of the insulating film in the covered state is provided for another exemplary embodiment of this application.

[0014] Figure 7 A schematic diagram of the structure of the insulating film in the covered state is provided for another exemplary embodiment of this application.

[0015] Figure 8 A schematic diagram of the structure of a battery cell provided in an exemplary embodiment of this application from a second perspective.

[0016] Figure 9 A cross-sectional view of a pole group provided for an exemplary embodiment of this application.

[0017] Figure 10 A schematic diagram of the structure of a battery cell provided for another exemplary embodiment of this application.

[0018] Figure 11 for Figure 10 A partial cross-sectional view of the battery cell shown.

[0019] Figure 12 A simplified structural diagram of the housing provided for an exemplary embodiment of this application.

[0020] Figure 13 A simplified structural diagram of a pole group provided for an exemplary embodiment of this application.

[0021] Figure 14 A simplified structural diagram of the housing portion after it is covered with an insulating film, as provided in an exemplary embodiment of this application.

[0022] Figure 15 A simplified structural diagram of the main body after it is covered with an insulating film, as provided in an exemplary embodiment of this application.

[0023] Reference numerals: 100-cell; 110-pole group; 111-first sidewall; 112-second sidewall; 113-third sidewall; 114-fourth sidewall; 115-sub-pole group; 116-casing portion; 117-main body portion; 120-insulating film; 121-first covering surface; 1211-first through hole; 1212-first folded surface; 12121-first side; 12122-second side; 1213-first connecting surface ; 1214-Second folded surface; 12141-Third side; 12142-Fourth side; 122-Second covering surface; 1221-Second through hole; 1222-Third folded surface; 12221-Fifth side; 12222-Sixth side; 1223-Second connecting surface; 1224-Fourth folded surface; 12241-Seventh side; 12242-Eighth side; 123-Third covering surface; 1231-First extension Surface; 1232 - Second extended surface; 1233 - First inclined wall; 1234 - Second inclined wall; 1235 - Third inclined wall; 1236 - Fourth inclined wall; 1237 - Impregnation hole; 1238 - Positioning hole; 124 - Bonding window; 1241 - First window; 1243 - First inner wall; 1244 - Second inner wall; 1245 - Sub-window; 125 - First groove; 126 - Second groove; 127 - First clearance area; 1 28 - Second clearance area; 129 - Third clearance area; 130 - Fourth clearance area; 131 - Third groove; 132 - Fourth groove; 133 - Fifth groove; 134 - Sixth groove; 135 - First gap; 136 - Second gap; 140 - First adhesive component; 141 - First edge; 142 - Second edge; 150 - Second adhesive component; 151 - Fifth edge; 152 - Sixth edge; 160 - Housing. Detailed Implementation

[0024] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0025] Figure 1 A schematic diagram of the structure of a battery cell provided in an exemplary embodiment of this application from a first-view perspective. Figure 2 This is a schematic diagram of the structure of a battery cell after the first adhesive component has been removed, as provided in an exemplary embodiment of this application. Figure 3This is a schematic diagram of the structure of a pole group provided for an exemplary embodiment of this application. Figure 4 This is a schematic diagram of the structure of an insulating film in its unfolded state, provided as an exemplary embodiment of this application. Figures 1 to 4 As shown, this application provides a battery cell 100, which may include an electrode group 110, an insulating film 120, and a first adhesive 140.

[0026] It should be noted that the electrode assembly 110 is usually made by winding or stacking positive electrode plates, negative electrode plates and separators, and is roughly square in structure.

[0027] It should be noted that the insulating film 120 can cover the outer wall of the electrode group 110. During the process of the electrode group 110 being installed into the housing 160 (described later), on the one hand, the insulating film 120 can prevent the housing 160 from scratching the surface of the electrode group 110, and on the other hand, the insulating film 120 can prevent the metal housing 160 from directly contacting the electrode group 110, thus avoiding short circuits.

[0028] like Figure 1 and Figure 2 As shown, the insulating film 120 is provided with an adhesive window 124 through which a portion of the outer wall of the electrode assembly 110 can be exposed.

[0029] like Figure 1 and Figure 2 As shown, the first adhesive member 140 can simultaneously adhere the insulating film 120 and the exposed outer wall of the electrode assembly 110 through the adhesive window 124. In this way, the first adhesive member 140 can bond and fix the insulating film 120 and the electrode assembly 110, reducing the risk that the insulating film 120 may easily shift or even fall off during the insertion of the electrode assembly 110 into the housing.

[0030] The battery cell 100 provided in this application embodiment directly bonds the electrode assembly 110 body to the bonding window 124 of the insulating film 120 via the first adhesive member 140. This achieves relative fixation between the insulating film 120 and the electrode assembly 110, avoiding the use of a hot-melt process and thus eliminating the problems associated with the hot-melt process (complex process and high manufacturing cost). Furthermore, compared to a structure where the insulating film 120 simply wraps around the electrode assembly 110 without any fixation, the first adhesive member 140 in this application embodiment can bond and fix the insulating film 120 and the electrode assembly 110, reducing the risk of the insulating film 120 shifting or even falling off during the electrode assembly 110 insertion into the housing. This ensures the assembly reliability between the electrode assembly 110 and the housing 160 and improves assembly efficiency.

[0031] In one embodiment, the first adhesive 140 may include tape, structural adhesive layer, etc.

[0032] Figure 5This embodiment of the invention provides a structural schematic diagram of the insulating film in its encapsulated state. For example... Figure 4 and Figure 5 As shown, the insulating film 120 includes a first covering surface 121 and a second covering surface 122. When the insulating film 120 covers the outer wall of the electrode assembly 110, the first covering surface 121 is provided with a first through hole 1211 and the second covering surface 122 is provided with a second through hole 1221.

[0033] It should be noted that the bonding window 124 formed by the first through hole 1211 and the second through hole 1221 can include at least the following situations: In the first scenario, the first through-hole 1211 forms a separate bonding window 124, and the second through-hole 1221 forms another separate bonding window 124. The first through-hole 1211 and the second through-hole 1221 are along a third direction (which can be understood as the length direction of the electrode assembly 110, see reference). Figure 1 and Figure 2 The two components are relatively distributed in the Y-axis direction. One first adhesive component 140 can bond the insulating film 120 and the first sidewall 111 of the electrode group 110 along the third direction (see the description below) through the first through hole 1211. The other first adhesive component 140 can bond the insulating film 120 and the second sidewall 112 of the electrode group 110 along the third direction (see the description below) through the second through hole 1221.

[0034] In the second case, the first through hole 1211 and the second through hole 1221 are located on the same side of the pole group 110 along the third direction (e.g., on the first sidewall 111 or the second sidewall 112 in this document), and the first through hole 1211 and the second through hole 1221 are combined to form the aforementioned adhesive window 124.

[0035] In the third case, the first through hole 1211 and the second through hole 1221 are located on the same side of the pole group 110 along the third direction (e.g., on the same first sidewall 111 or on the same second sidewall 112 in this document), and the first through hole 1211 and the second through hole 1221 are distributed to form independent bonding windows 124.

[0036] It should be noted that, in the first case mentioned above, the number of the first through hole 1211 and the second through hole 1221 may be equal or unequal.

[0037] It should be noted that in the second case mentioned above, the number of the first through hole 1211 and the second through hole 1221 are equal, and they correspond one-to-one to form the bonding window 124.

[0038] It should be noted that in the third case mentioned above, the number of the first through hole 1211 and the second through hole 1221 may be equal or unequal.

[0039] It should be noted that in actual production, the first through hole 1211 and the second through hole 1221 are pre-processed on the first covering surface 121 and the second covering surface 122 of the insulating film 120, and then the bonding window 124 is formed during the covering process. There is no need to perform a complicated window opening operation after the insulating film 120 is covered, which can simplify the production process and improve production efficiency.

[0040] In one embodiment, the shape of the first through hole 1211 can be circular, rectangular, polygonal, etc. Similarly, the shape of the second through hole 1221 can also be circular, rectangular, polygonal, etc.

[0041] In one embodiment, the first through hole 1211 and the second through hole 1221 may have the same or different shapes.

[0042] like Figure 1 and Figure 5 As shown, with the insulating film 120 covering the outer wall of the electrode assembly 110, the insulating film 120 extends along the first direction (which can be understood as the thickness or width direction of the electrode assembly 110, see reference). Figure 1 and Figure 5 The length of the bonding window 124 along the first direction (in the X-axis direction) is A1, and the total length of the bonding window 124 along the first direction is L1. A1 and L1 satisfy the relationship: 5mm≤L1≤A1. This dimensional relationship can bring the following technical effects: First, setting the lower limit of L1 to 5mm ensures that the bonding window 124 has sufficient length along the first direction, so that the first adhesive 140 can have sufficient area to bond with the outer wall of the electrode assembly 110, avoiding the problem of weak bonding due to the bonding window 124 being too small. Second, L1 does not exceed A1, which reasonably restricts the boundary of the bonding window 124 within the boundary of the side wall of the electrode assembly 110, avoiding the bonding window 124 being too large, causing the electrode assembly 110 to directly contact the housing 160, thereby causing a short circuit problem.

[0043] like Figure 1 and Figure 5 As shown, with the insulating film 120 covering the outer wall of the electrode assembly 110, the insulating film 120 is positioned along the second direction (which can be understood as the height direction of the electrode assembly 110, see reference). Figure 1 and Figure 5The length of the bonding window 124 along the second direction (in the Z-axis direction) is A2, and the length of the bonding window 124 along the second direction is L2. A2 and L2 satisfy the relationship: 5mm≤L2≤A2. This dimensional relationship can bring the following technical effects: First, setting the lower limit of L2 to 5mm ensures that the bonding window 124 has sufficient length along the second direction, so that the first adhesive 140 can have sufficient area to bond with the outer wall of the electrode assembly 110, avoiding the problem of weak bonding due to the bonding window 124 being too small. Second, L2 does not exceed A2, which reasonably restricts the boundary of the bonding window 124 within the boundary of the side wall of the electrode assembly 110, avoiding the bonding window 124 being too large, causing the electrode assembly 110 to directly contact the housing 160 and thus causing a short circuit problem.

[0044] It should be noted that by limiting the length of the bonding window 124 in the first and second directions, it can be ensured that the bonding window 124 is an effective area for the first adhesive member 140 to bond to the outer wall of the electrode assembly 110, rather than a symbolic small hole, which can effectively ensure the fixing effect.

[0045] Figure 6 A schematic diagram of the structure of the insulating film in the covered state is provided for another exemplary embodiment of this application. Figure 7 A schematic diagram of the insulating film in its encapsulated state is provided for another exemplary embodiment of this application. (Combined with...) Figures 5 to 7 By adjusting the overlap area of ​​the first covering surface 121 and the second covering surface 122, the overlap area of ​​the first through hole 1211 and the second through hole 1221 can be adjusted, thereby adjusting the size and opening position of the bonding window 124. This structure, which allows for flexible adjustment of the size and position of the bonding window 124, can adapt to different electrode assembly 110 sizes, effectively expanding the application range. Based on this structure, before assembling the electrode assembly 110, the optimal fixing position of the electrode assembly 110 (e.g., the side of the electrode assembly 110 with a smaller area, refer to the first sidewall 111 and / or the second sidewall 112 in this document) and the required bonding area can be determined. Then, by adjusting the overlap area of ​​the first covering surface 121 and the second covering surface 122, the size and opening position of the bonding window 124 can be adjusted. This not only ensures a stable fixing effect but also eliminates the need to replace the insulating film 120 of a different size, greatly improving production efficiency.

[0046] In one embodiment, the first covering surface 121 and the second covering surface 122 may be completely overlapping or partially overlapping.

[0047] like Figure 6 and Figure 7 As shown, the bonding window 124 includes a plurality of sub-windows 1245 spaced apart along a first direction, and the sum of the lengths of the plurality of sub-windows 1245 along the first direction is the aforementioned L1.

[0048] It should be understood that, depending on the overlap of the first covering surface 121 and the second covering surface 122, the bonding window 124 can be composed of multiple sub-windows 1245 distributed along the first direction. By adjusting the overlap of the first covering surface 121 and the second covering surface 122, the distribution and number of sub-windows 1245 can be adjusted.

[0049] In practical applications, the outer walls exposed by the multiple sub-windows 1245 of the electrode assembly 110 can all be used to bond the aforementioned first adhesive member 140. In this way, firstly, targeted bonding can be performed on different parts of the outer wall of the electrode assembly 110, so as to achieve a more balanced and effective fixation of the insulating film 120 and the electrode assembly 110; secondly, since the electrode assembly 110 usually has curved sidewalls (such as the first sidewall 111 and the second sidewall 112 in this article), the multiple sub-windows 1245 can more reasonably correspond to the position of maximum curvature of the curved sidewall, so that each first adhesive member 140 can fit more closely to the surface of the electrode assembly 110, thereby effectively improving the fixation effect of the first adhesive member 140 on the electrode assembly 110 and the insulating film 120.

[0050] like Figure 6 and Figure 7 As shown, the length of sub-window 1245 along the first direction is L3, and L3 satisfies: 3mm≤L3<L1.

[0051] It should be noted that the length L3 of different sub-windows 1245 along the first direction can be the same or different.

[0052] It should be noted that setting the lower limit of L3 to 3mm ensures that each sub-window 1245 has sufficient length along the first direction, so that the first adhesive 140 can have sufficient area to bond with the outer wall of the electrode group 110, thus avoiding the problem that the first adhesive 140 may detach from the outer wall of the electrode group 110 due to the factor window 1245 being too small.

[0053] It should be noted that the area of ​​a single sub-window 1245 is F1, and F1 satisfies: F1≥10mm². Setting the lower limit of F1 to 3mm ensures that the outer wall of the electrode assembly 110 can be exposed with a sufficiently large area through each sub-window 1245 to bond with the first adhesive 140, thus avoiding the problem of the first adhesive 140 detaching from the outer wall of the electrode assembly 110 due to the sub-window 1245 being too small.

[0054] In one embodiment, the areas F1 of different sub-windows 1245 may be the same or different.

[0055] It should be noted that the total area of ​​the bonding window 124 is F2, and F2 satisfies: F2≥50mm². Setting the lower limit of F2 to 50mm ensures that the outer wall of the electrode assembly 110 can be exposed with a sufficiently large area through the bonding window 124 to bond with the first adhesive component 140, thus avoiding the problem of the first adhesive component 140 detaching from the outer wall of the electrode assembly 110 due to the factor window 1245 being too small.

[0056] like Figure 1 and Figure 2 As shown, the bonding window 124 includes a third direction (which can be understood as the length direction of the pole group 110, see reference for details). Figure 3 The first window 1241 and the second window (not shown in the figure) are relatively distributed on both sides of the pole group 110 in the Y-axis direction. Figure 3 As shown, the pole group 110 includes poles along a third direction (which can be understood as the length direction of the pole group 110, see reference for details). Figure 3 The first sidewall 111 and the second sidewall 112 are relatively distributed along the Y-axis. A portion of the first sidewall 111 is exposed through the first window 1241, and a portion of the second sidewall 112 is exposed through the second window.

[0057] It should be understood that the first adhesive 140 can fix the insulating film 120 and the first sidewall 111 through the first window 1241, and the first adhesive 140 can fix the insulating film 120 and the second sidewall 112 through the second window. In this way, the insulating film 120 can be constrained from two opposite directions, which can effectively suppress the overall displacement or torsion of the insulating film 120, making the structure after covering more stable, greatly improving the fixing effect, and further reducing the risk of the insulating film 120 shifting or falling off due to poor fixing effect during the shell insertion process.

[0058] In one embodiment, the first adhesive 140 that bonds the first sidewall 111 and the second sidewall 112 can be a single unit or separate parts.

[0059] like Figure 3 As shown, the pole group 110 also includes poles along a first direction (reference). Figure 3The third sidewall 113 and the fourth sidewall 114 are relatively distributed along the X-axis direction. The areas of the third sidewall 113 and the fourth sidewall 114 are both larger than the area of ​​the first sidewall 111, and also larger than the area of ​​the second sidewall 112. That is to say, in this embodiment, the bonding window 124 is set on the smaller area of ​​the first sidewall 111 and the second sidewall 112. In this way, on the one hand, compared with the larger area sidewalls (the third sidewall 113 and the fourth sidewall 114), the adhesive force applied on the smaller area sidewalls (the first sidewall 111 and the second sidewall 112) can be more concentrated on the insulating film 120. When the electrode assembly 110 is inserted into the housing, the insulating film 120 is less likely to shift or fall off. On the other hand, it can be ensured that the larger area third sidewall 113 and the fourth sidewall 114 in the electrode assembly 110 are continuously and completely covered by the insulating film 120, ensuring the insulating and protective effect of the insulating film 120 on the electrode assembly 110.

[0060] In one embodiment, the third sidewall 113 and the fourth sidewall 114 have equal areas, and the first sidewall 111 and the second sidewall 112 have equal areas.

[0061] like Figure 4 As shown, in the unfolded state of the insulating film 120, the first covering surface 121 includes a first folded surface 1212, a first connecting surface 1213, and a second folded surface 1214. The first connecting surface 1213 is located between the first folded surface 1212 and the second folded surface 1214, and connects the first folded surface 1212 and the second folded surface 1214. Both the first folded surface 1212 and the second folded surface 1214 are provided with a first through hole 1211. Correspondingly, in the unfolded state of the insulating film 120, the second covering surface 122 includes a third folded surface 1222, a second connecting surface 1223, and a fourth folded surface 1224. The second connecting surface 1223 is located between the third folded surface 1222 and the fourth folded surface 1224, and connects the third folded surface 1222 and the fourth folded surface 1224. Both the third folded surface 1222 and the fourth folded surface 1224 are provided with a second through hole 1221.

[0062] When the insulating film 120 covers the electrode assembly 110, the first through hole 1211 on the first folded surface 1212 and the second through hole 1221 on the third folded surface 1222 correspond to form a first window 1241; the first through hole 1211 on the second folded surface 1214 and the second through hole 1221 on the fourth folded surface 1224 correspond to form a second window.

[0063] It should be understood that during the process of covering the insulating film 120, the first through hole 1211 and the second through hole 1221 can be aligned and positioned with each other. Through simple folding actions of the first folding surface 1212, the second folding surface 1214, the third folding surface 1222 and the fourth folding surface 1224, the first window 1241 and the second window can be quickly formed, which is beneficial to improving the forming efficiency of the first window 1241 and the second window.

[0064] In one embodiment, the number of first through holes 1211 on the first folded surface 1212 is multiple, and the number of first through holes 1211 on the third folded surface 1222 is the same as the number of first through holes 1211 on the first folded surface 1212, and they correspond one-to-one, so that multiple different first windows 1241 can be formed.

[0065] In one embodiment, the number of second through holes 1221 on the second folded surface 1214 is multiple, and the number of second through holes 1221 on the fourth folded surface 1224 is the same as the number of second through holes 1221 on the second folded surface 1214, and they correspond one-to-one, thus forming multiple different second windows.

[0066] like Figure 4 As shown, the first folded surface 1212 includes a fourth direction (which can be understood as the width direction of the insulating film 120 in the unfolded state, see reference for details). Figure 4 The first side 12121 extends in the direction indicated by the middle arrow T) and along the fifth direction (which can be understood as the length direction of the insulating film 120 in the unfolded state, see reference for details). Figure 4 The distance between the first through hole 1211 on the first folded surface 1212 and the first side 12121 along the fifth direction is E1, and E1 satisfies: E1≥3mm; the distance between the first through hole 1211 on the first folded surface 1212 and the second side 12122 along the fourth direction is E2, and E2 satisfies: E2≥3mm.

[0067] Similarly, the second folded surface 1214 includes a third side 12141 extending along the fourth direction and a fourth side 12142 extending along the fifth direction. The distance between the first through hole 1211 and the third side 12141 on the second folded surface 1214 along the fifth direction is E3, where E3 satisfies: E3≥3mm; the distance between the first through hole 1211 and the fourth side 12142 on the second folded surface 1214 along the fourth direction is E4, where E4 satisfies: E4≥3mm.

[0068] Similarly, the third folded surface 1222 includes a fifth side 12221 extending along the fourth direction and a sixth side 12222 extending along the fifth direction. The distance between the second through hole 1221 on the third folded surface 1222 and the fifth side 12221 along the fifth direction is E5, and E5 satisfies: E5≥3mm; the distance between the second through hole 1221 on the third folded surface 1222 and the sixth side 12222 along the fourth direction is E6, and E6 satisfies: E6≥3mm.

[0069] Similarly, the fourth folded surface 1224 includes a seventh side 12241 extending along the fourth direction and an eighth side 12242 extending along the fifth direction. The distance between the second through hole 1221 and the seventh side 12241 on the fourth folded surface 1224 along the fifth direction is E7, and E7 satisfies: E7≥3mm; the distance between the second through hole 1221 and the eighth side 12242 on the fourth folded surface 1224 along the fourth direction is E8, and E8 satisfies: E8≥3mm.

[0070] It should be noted that setting the lower limit of E1, E2, E3, E4, E5, E6, E7, and E8 to 3mm serves two purposes. First, it ensures that sufficient insulating material is retained around the first through hole 1211 and the second through hole 1221, which enhances the overall structural strength and tear resistance of each folded surface (e.g., the first folded surface 1212, the second folded surface 1214, the third folded surface 1222, and the fourth folded surface 1224) during the punching process, preventing damage during punching due to the hole being too close to the edge. Second, it ensures that when the first adhesive component 140 is bonded through the adhesive window 124, there is sufficient insulating material around the adhesive window 124 for the first adhesive component 140 to bond, providing a stable and reliable bonding foundation between the first adhesive component 140 and the insulating film 120, thus ensuring the durability and reliability of the bonding.

[0071] like Figure 4 As shown, a third groove 131 is provided between the first folded surface 1212 and the first connecting surface 1213; and / or, a fourth groove 132 is provided between the second folded surface 1214 and the first connecting surface 1213; and / or, a fifth groove 133 is provided between the third folded surface 1222 and the second connecting surface 1223; and / or, a sixth groove 134 is provided between the fourth folded surface 1224 and the second connecting surface 1223.

[0072] It should be noted that these grooves guide the insulating film 120 to bend along a predetermined path, ensuring that each folded surface can be accurately folded to the predetermined position. This allows the first through hole 1211 and the second through hole 1221 on different folded surfaces to be perfectly aligned, forming a complete and accurately positioned bonding window 124. The complete and accurately positioned bonding window 124 improves the fixing effect of the first adhesive 140 on the insulating film 120 and the electrode assembly 110, further enhancing the fixing stability.

[0073] In one embodiment, the number of third grooves 131 can be one, two, three, etc. Similarly, the number of fourth grooves 132 can be one, two, three, etc. The number of fifth grooves 133 can be one, two, three, etc. The number of sixth grooves 134 can be one, two, three, etc.

[0074] It should be noted that the third groove 131, the fourth groove 132, the fifth groove 133, and the sixth groove 134 are all non-penetrating structures, which can reduce the risk of cracks appearing in the third groove 131, the fourth groove 132, the fifth groove 133, and the sixth groove 134 during the folding process. This helps to ensure the overall structural strength of the insulating film 120 and improve the overall reliability and durability of the insulating film 120.

[0075] like Figure 4 As shown, the insulating film 120 may further include a third covering surface 123, which is located between the first connecting surface 1213 and the second connecting surface 1223, and connects the first connecting surface 1213 and the second connecting surface 1223.

[0076] In practical applications, the third covering surface 123 can be used to cover the bottom wall of the electrode group 110 to prevent the bottom wall of the electrode group 110 from being scratched by the housing 160. At the same time, it can also prevent the bottom wall of the electrode group 110 from directly contacting the housing 160 to avoid short circuit accidents.

[0077] like Figure 4 As shown, a first groove 125 is provided between the third covering surface 123 and the first connecting surface 1213; and / or, a second groove 126 is provided between the third covering surface 123 and the second connecting surface 1223.

[0078] In practical applications, the third covering surface 123 can cover the bottom wall of the electrode assembly 110, while the first connecting surface 1213 and the second connecting surface 1223, after being bent relative to the third covering surface 123, can cover the side walls of the electrode assembly 110 (such as the aforementioned third side wall 113 and fourth side wall 114). This allows the insulating film 120 to fully wrap the electrode assembly 110 in a "U"-shaped structure, providing more effective protection for the electrode assembly 110.

[0079] It should be noted that the first groove 125 can guide the path of the first connecting surface 1213 folding relative to the third covering surface 123, and the second groove 126 can guide the path of the second connecting surface 1223 folding relative to the third covering surface 123, ensuring that the first connecting surface 1213 and the second connecting surface 1223 can accurately cover the sidewalls of the pole group 110 (such as the aforementioned third sidewall 113 and fourth sidewall 114).

[0080] In one embodiment, the number of first grooves 125 can be one, two, three, etc. Similarly, the number of second grooves 126 can be one, two, three, etc.

[0081] It should be noted that both the first notch 125 and the second notch 126 are non-penetrating structures, which can reduce the risk of cracks appearing in the first notch 125 and the second notch 126 during the folding process, help to ensure the overall structural strength of the insulating film 120, and improve the overall reliability and durability of the insulating film 120.

[0082] like Figure 4 As shown, in the unfolded state of the insulating film 120, the third covering surface 123 includes a fourth direction (which can be understood as the width direction of the insulating film 120 in the unfolded state, see reference for details). Figure 4 The first extension surface 1231 and the second extension surface 1232 are relatively distributed in the direction indicated by the middle arrow T.

[0083] In one embodiment, when the first groove 125 and the second groove 126 are parallel, the length directions of the first groove 125 and the second groove 126 are the same. The fourth direction can also be understood as the length direction of the first groove 125 and / or the second groove 126.

[0084] like Figure 4 As shown, the first extension surface 1231 and the first folded surface 1212 are along the fifth direction (which can be understood as the length direction of the insulating film 120 in the unfolded state, see reference for details). Figure 4 The areas between the first extended surface 1231 and the first folded surface 1212 are spaced apart (in the direction indicated by the middle arrow W), forming a first clearance zone 127; and / or, the first extended surface 1231 and the third folded surface 1222 are spaced apart along the fifth direction, forming a second clearance zone 128; and / or, the second extended surface 1232 and the second folded surface 1214 are spaced apart along the fifth direction, forming a third clearance zone 129; and / or, the second extended surface 1232 and the fourth folded surface 1224 are spaced apart along the fifth direction, forming a fourth clearance zone 130.

[0085] It should be noted that the arrangement of the first avoidance zone 127, the second avoidance zone 128, the third avoidance zone 129 and the fourth avoidance zone 130 provides the necessary buffer space for the insulating film 120 during the folding process. Specifically, when the first extension surface 1231, the second extension surface 1232, and each folded surface (first folded surface 1212, second folded surface 1214, third folded surface 1222, and fourth folded surface 1224) are relatively bent and brought together, these reserved avoidance areas (first avoidance area 127, second avoidance area 128, third avoidance area 129, and fourth avoidance area 130) can effectively accommodate the space occupied by different surfaces at the corners due to material thickness and bending radius, ensuring that no problems such as squeezing or stacking occur after each surface is folded. This can prevent the insulating film 120 from wrinkling after covering the electrode assembly 110. This not only ensures that the insulating film 120 has the same insulation performance in different parts, but also helps to improve the smoothness of the electrode assembly 110 and the insulating film 120 in the process of entering the housing 160, and reduces the pressure between the insulating film 120 and the housing 160.

[0086] like Figure 4 As shown, a first inclined wall 1233 is provided on the side of the first extension surface 1231 near the first clearance area 127, and the first inclined wall 1233 is connected to the fourth direction (reference). Figure 4 The angle between the direction indicated by the middle arrow T and the direction is K1, and K1 satisfies: 0≤K1≤60°; and / or, the side of the first extension surface 1231 near the second clearance area 128 is provided with a second inclined wall 1234, and the angle between the second inclined wall 1234 and the fourth direction is K2, and K2 satisfies: 0≤K2≤60°; and / or, the side of the second extension surface 1232 near the third clearance area 129 is provided with a third inclined wall 1235, and the angle between the third inclined wall 1235 and the length direction of the first groove 125 and / or the second groove 126 is K3, and K3 satisfies: 0≤K3≤60°; and / or, the side of the second extension surface 1232 near the fourth clearance area 130 is provided with a fourth inclined wall 1236, and the angle between the fourth inclined wall 1236 and the length direction of the first groove 125 and / or the second groove 126 is K4, and K4 satisfies: 0≤K4≤60°.

[0087] Taking K1 as an example, when K1 is 0°, the edge of the first extension surface 1231 is a right angle, which can improve the utilization rate of materials and is suitable for thinner and more resilient membrane materials. As K1 increases to 60°, the first inclined wall 1233 can distribute the stress during folding to a longer inclined surface, avoiding stress concentration. At the same time, the first inclined wall 1233 can guide the first extension surface 1231 and the first folding surface 1212 to fold accurately and smoothly to the predetermined position, preventing interference problems. If K1 is too large, it will cause a sharp fold angle between the first extension surface 1231 and the first folding surface 1212 after folding, which is prone to stress concentration and increases the risk of tearing of the first inclined wall 1233. Therefore, K1 is limited to the following range: 0≤K1≤60°. Similarly, K2 is limited to the following range: 0 ≤ K2 ≤ 60°; K3 is limited to the following range: 0 ≤ K3 ≤ 60°; K4 is limited to the following range: 0 ≤ K4 ≤ 60°.

[0088] like Figure 4 As shown, the third covering surface 123 may be provided with wetting holes 1237. The wetting holes 1237 provide an additional flow channel for the electrolyte during the electrolyte injection process of the battery cell 100. Specifically, the electrolyte can penetrate more quickly into the electrode assembly 110 covered by the insulating film 120 through the wetting holes 1237, thereby effectively shortening the wetting time after electrolyte injection and improving production efficiency.

[0089] In one embodiment, the wetting hole 1237 can be a strip-shaped hole, and the number of wetting holes 1237 can be one, two, three, etc.

[0090] like Figure 4 As shown, the third covering surface 123 may also be provided with positioning holes 1238. In the covering process and subsequent assembly process, with the help of positioning holes 1238, positioning components on other equipment can be aligned with positioning holes 1238 to achieve precise positioning of insulating film 120 and electrode group 110, ensuring the accuracy of the relative positions of each component, which is conducive to improving covering accuracy and assembly accuracy.

[0091] Figure 8 A schematic diagram of the battery cell provided as an exemplary embodiment of this application, viewed from a second perspective. Figure 8 As shown, the first adhesive element 140 and the first covering surface 121 are along the first direction (which can be understood as the thickness direction or width direction of the electrode assembly 110, see reference for details). Figure 8The bonding overlap length (in the X-axis direction) is C1, satisfying 3mm ≤ C1 ≤ 50mm. The aforementioned dimensional relationship brings the following technical effects: First, setting the lower limit of C1 to 3mm ensures that the first adhesive component 140 has a sufficiently long portion to bond to the insulating film 120, guaranteeing the reliability of the bond between the first adhesive component 140 and the insulating film 120. If the bonding overlap length C1 is too short, the adhesive force may be insufficient, and the insulating film 120 may easily detach from the electrode assembly 110 during the installation process. Second, setting the upper limit of C1 to 50mm ensures sufficient strength while avoiding excessive use of the first adhesive component 140, saving material costs, and preventing other problems that may arise from an excessively long first adhesive component 140, such as affecting heat dissipation efficiency.

[0092] like Figure 8 As shown, the bonding overlap length between the first adhesive component 140 and the second covering surface 122 along the first direction is C2, which satisfies 3mm ≤ C2 ≤ 50mm. Similarly, setting the lower limit of C2 to 3mm ensures that the first adhesive component 140 has a sufficiently long portion to bond to the insulating film 120, guaranteeing the bonding reliability between the first adhesive component 140 and the insulating film 120. If the bonding overlap length C2 is too short, the adhesive force may be insufficient, and the insulating film 120 may easily detach from the electrode assembly 110 during the process of inserting the electrode assembly 110 into the housing. Secondly, setting the upper limit of C2 to 50mm ensures sufficient strength while avoiding excessive use of the first adhesive component 140, saving material costs, and preventing other problems that may be caused by the first adhesive component 140 being too long, such as affecting heat dissipation efficiency.

[0093] In one embodiment, two different first adhesive members 140 are bonded within the same adhesive window 124. One first adhesive member 140 bonds the electrode assembly 110 and the first covering surface 121, and the bonding overlap length between this first adhesive member 140 and the first covering surface 121 along the first direction is C1. The other first adhesive member 140 bonds the electrode assembly 110 and the second covering surface 122, and the bonding overlap length between this first adhesive member 140 and the second covering surface 122 along the first direction is C2.

[0094] In one embodiment, C1 can be selected from 3mm, 5mm, 10mm, 50mm, etc. Similarly, C2 can be selected from 3mm, 5mm, 10mm, 50mm, etc.

[0095] like Figure 8 As shown, the first adhesive member 140 includes a second direction (which can be understood as the height direction of the pole group 110, see reference for details). Figure 8The first edge 141 and the second edge 142 are relatively distributed along the Z-axis direction. Correspondingly, the adhesive window 124 includes a first inner wall 1243 and a second inner wall 1244 relatively distributed along the second direction. After the first adhesive 140 is bonded, the first edge 141 and the second edge 142 are both located between the first inner wall 1243 and the second inner wall 1244. A first gap 135 is formed between the first edge 141 and the first inner wall 1243, and a second gap 136 is formed between the second edge 142 and the second inner wall 1244.

[0096] It should be noted that by pre-leaving the aforementioned first gap 135 and second gap 136 between the edge of the first adhesive member 140 and the inner wall of the adhesive window 124, it can be ensured that the first adhesive member 140 can fully adhere to the outer wall of the electrode group 110 through the adhesive window 124. This avoids the problem of the first adhesive member 140 being in contact with the edge of the adhesive window 124 and having a loose bond with the outer wall of the electrode group 110, which would prevent the first adhesive member 140 from effectively adhering to the outer wall of the electrode group 110 and thus affect the fixing effect between the insulating film 120 and the electrode group 110.

[0097] Furthermore, the length of the first gap 135 along the second direction is D1. If D1 is too small, the first edge 141 may come into contact with the first inner wall 1243, affecting the bonding stability between the first adhesive 140 and the outer wall of the electrode assembly 110. If D1 is too large, the exposed area of ​​the electrode assembly 110 through the first gap 135 may be too large, making it easy to be scratched by the housing 160, or the outer wall of the electrode assembly 110 may come into contact with the housing 160 through the first gap 135, causing a short circuit. Therefore, in this embodiment, the length D1 is limited to the following range: 1mm ≤ D1 ≤ 3mm, which can effectively improve the problems caused by D1 being too large or too small.

[0098] Similarly, the length D2 of the second gap 136 along the second direction is limited to the following range: 1mm≤D2≤3mm. This can ensure the bonding stability between the first adhesive 140 and the outer wall of the electrode group 110, prevent the electrode group 110 from being scratched by the housing 160, and prevent the outer wall of the electrode group 110 from contacting the housing 160 through the second gap 136, thus preventing a short circuit.

[0099] Figure 9 A cross-sectional view of a pole group provided for an exemplary embodiment of this application. (See attached image.) Figure 9 As shown, the pole group 110 includes multiple sub-pole groups 115, which are distributed along a first direction. The length of a single sub-pole group 115 along the first direction is A3, and the length of the bonding window 124 along the first direction is L1. A3 and L1 satisfy: L1≥0.25A3.

[0100] It should be noted that the sidewall of the sub-pole group 115 is usually curved. By limiting the length L1 of the bonding window 124 to be no less than one-quarter of the length A3 of a single sub-pole group 115, it is ensured that the bonding window 124 is sufficient to cover a sufficiently long effective section on the curved surface of the sub-pole group 115, so that the first adhesive 140 can achieve reliable bonding in the sub-pole group 115.

[0101] Furthermore, along the first direction, the longer adhesive window 124 can span the recess between adjacent sub-pole groups 115. It should be understood that if only the same first adhesive piece 140 is used to cover the curved surface of adjacent sub-pole groups 115, the first adhesive piece 140 may be unbonded at the recess due to being suspended. Therefore, in conjunction with... Figure 1 In this embodiment, the outer walls of two adjacent sub-electrode groups 115 exposed in the bonding window 124 are respectively bonded with different first adhesive members 140. Each first adhesive member 140 can closely fit the curvature of the arc surface of the corresponding sub-electrode group 115 to achieve the maximum effective contact area, effectively improve the bonding stability of the first adhesive member 140, thereby improving the overall coating stability between the electrode group 110 and the insulating film 120.

[0102] Figure 10 A schematic diagram of the structure of a battery cell provided for another exemplary embodiment of this application. Figure 10 and Figure 1 The difference lies in the addition of a second adhesive component 150. Specifically, as shown... Figure 10 As shown, the battery cell 100 may also include a second adhesive 150, which is bonded to the side of the first adhesive 140, the first covering surface 121 and the second covering surface 122 away from the electrode group 110.

[0103] In other words, the second adhesive 150 covers the entire area where the first adhesive 140 and the bonding window 124 are located, providing double protection for the stability and safety of the bonding. Specifically, the first adhesive 140, as the inner layer, mainly serves to fix the insulating film 120 to the electrode group 110. The second adhesive 150, as the outer layer, completely covers the first adhesive 140 and the bonding window 124. Thus, on the one hand, when the first adhesive 140 experiences partial bonding failure, the second adhesive 150 can still prevent the first adhesive 140 from falling off, ensuring that the insulating film 120 and the electrode group 110 remain in a relatively fixed state for a long time; on the other hand, regarding the risk that the electrode group 110 may be scratched by the housing 160 or short-circuit due to contact with the housing 160 at the edge area of ​​the bonding window 124, the second adhesive 150 can act as a complete insulating protective barrier, preventing the electrode group 110 from directly contacting the housing 160, thereby ensuring the integrity of the electrode group 110 and improving safety performance.

[0104] In one embodiment, the second adhesive 150 may include tape, structural adhesive layer, etc.

[0105] Figure 11 for Figure 10 A partial cross-sectional view of the battery cell is shown. (As shown) Figure 11 As shown, the bonding window 124 includes a second direction (reference). Figure 10 and Figure 11 The first inner wall 1243 and the second inner wall 1244 are relatively distributed in the Z-axis direction; the second adhesive 150 includes a fifth edge 151 and a sixth edge 152 that are relatively distributed in the second direction.

[0106] It should be noted that the distance between the fifth edge 151 and the first inner wall 1243 along the second direction is H1, where H1 satisfies 3mm ≤ H1 ≤ 50mm; and / or, the distance between the sixth edge 152 and the second inner wall 1244 along the second direction is H2, where H2 satisfies 3mm ≤ H2 ≤ 50mm. The aforementioned dimensional relationships can bring the following technical effects: First, setting the lower limit of H1 and H2 to 3mm ensures that the second adhesive 150 can completely cover the adhesive window 124 along the second direction, sealing the gap between the inner wall of the adhesive window 124 and the first adhesive 140 (e.g., the first gap 135 and the second gap 136 in this document), preventing the sidewall of the electrode assembly 110 from directly contacting the housing 160; Second, setting the upper limit of H1 and H2 to 50mm ensures sufficient strength while avoiding excessive use of the second adhesive 150, saving material costs, and preventing other problems that may be caused by the excessive length of the second adhesive 150, such as affecting heat dissipation efficiency.

[0107] Figure 12 A simplified structural diagram of the housing provided for an exemplary embodiment of this application. (See diagram below.) Figure 12 As shown, the battery cell 100 may also include a housing 160, and the electrode assembly 110 may be assembled into the housing 160. The housing 160 provides support and protection for the electrode assembly 110.

[0108] Figure 13 A simplified structural diagram of a pole group provided for an exemplary embodiment of this application. (See diagram below.) Figure 13 As shown, the pole assembly 110 includes an inlet portion 116 and a main body portion 117 distributed along a second direction, both of which are disposed within the housing 160. In the actual assembly process, the inlet portion 116 first enters the housing 160 through the opening of the housing 160, and then guides the main body portion 117 to enter the housing 160 through the opening of the housing 160.

[0109] like Figure 12 As shown, the inner cavity of housing 160 is along a third direction (reference). Figure 12 The length along the Y-axis is M. Figure 14A simplified structural diagram of the housing portion after it has been covered with an insulating film, as provided in an exemplary embodiment of this application. Figure 14 As shown, the housing portion 116 and the insulating film 120 covering the outer wall of the housing portion 116 are arranged along a third direction (reference). Figure 14 The total length along the Y-axis (in the case of the part 116) is N1, and N1 and M satisfy: 0.5mm ≤ (M-N1) / 2 ≤ 5mm. This dimensional relationship essentially defines the width of the single-sided gap along the third direction between the housing 116 after the insulating film 120 is covered and the inner wall of the housing 160. In this dimensional relationship, setting the lower limit of the width of the single-sided gap along the third direction to 0.5mm ensures that even with manufacturing tolerances or assembly misalignment, the housing 116 can be smoothly inserted into the housing 160, avoiding assembly jamming problems caused by excessively small gaps. Setting the upper limit of the width of the single-sided gap along the third direction to 5mm, on the one hand, can limit the swaying amplitude of the housing 116 within the housing 160, improving assembly stability; on the other hand, it can reduce the space occupied by the single-sided gap, ensuring the energy density of the battery cell 100.

[0110] Figure 15 A simplified structural diagram of the main body after it has been covered with an insulating film, as provided in an exemplary embodiment of this application. Figure 12 and Figure 15 As shown, the main body 117 and the insulating film 120 covering the outer wall of the main body 117 are arranged in a third direction (reference). Figure 15 The length along the Y-axis (in the image) is N2, and N2 and M satisfy: 93.75%≤N2 / M≤101.25%. When N2 / M is between 93.75% and 100%, it exhibits a clearance fit, ensuring that the main body 117 and the insulating film 120 can be smoothly and completely installed; at the same time, setting the lower limit of N2 / M to 93.75% can, on the one hand, limit the swaying amplitude of the main body 117 within the housing 160, improving assembly stability, and on the other hand, reduce the space occupied by the gap between the main body 117 and the housing 160, ensuring the energy density of the cell 100. When N2 / M is between 100% and 101.25%, it exhibits an interference fit, and the housing 160 can exert slight pressure on the main body 117 and the insulating film 120, further enhancing the assembly stability of the main body 117 inside the housing 160. At the same time, setting the upper limit of N2 / M to 101.25% can prevent the housing 160 from applying excessive housing pressure to the main body 117 and the insulating film 120 during the housing insertion process (depending on the housing insertion direction, which will be described in detail later), avoiding scratches on the insulating film 120 and the main body 117 by the housing 160, and effectively reducing the housing insertion defect rate of the cell 100.

[0111] It should be noted that the ingress pressure exerted by the housing 160 on the main body 117 and the insulating film 120 can be understood as the frictional force between the housing 160 and the insulating film 120 covering the outside of the main body 117.

[0112] In one embodiment, when the battery cell 100 is assembled into the housing 160 in a vertical direction, considering the influence of gravity, by limiting the upper limit of N2 / M to 101.25%, it can be ensured that the housing pressure is not greater than 150N, which can prevent the insulating film 120 and the main body 117 from being scratched by the housing 160, and effectively reduce the housing defect rate of the battery cell 100.

[0113] In one embodiment, when the cell 100 is assembled into the housing 160 in a horizontal direction, by limiting the upper limit of N2 / M to 101.25%, it can be ensured that the housing pressure is not greater than 50N, which can further reduce the risk of the insulating film 120 and the main body 117 being scratched by the housing 160, and further reduce the housing defect rate of the cell 100.

[0114] like Figure 13 As shown, pole group 110 is along the second direction (reference). Figure 13 The length of the housing portion 116 along the Z-axis is S, and the length of the housing portion 116 along the second direction is R. R and S satisfy: 0 < R ≤ 0.25S. In this dimensional relationship, setting the upper limit to 0.25S can reduce the proportion of the housing portion 116 on the electrode group 110 while ensuring that the housing portion 116 achieves the aforementioned guiding housing function. This ensures that the main body portion 117 can have a larger proportion on the electrode group 110, reducing the loss of overall energy density of the cell 100 caused by housing guidance requirements (since the length of the housing portion 116 along the third direction is less than the length of the main body portion 117 along the third direction), thus ensuring the energy density of the cell 100.

[0115] This application also provides a battery pack, which may include a housing and a plurality of battery cells 100 as described in the previous embodiment, all of which are disposed within the housing. In practical applications, the plurality of battery cells 100 are connected in series and parallel and controlled by a battery management system.

[0116] The battery pack provided in this application embodiment includes all the functions of the aforementioned battery cell 100, and its beneficial effects can be referred to the beneficial effects of the aforementioned battery cell 100. Furthermore, since each battery cell 100 adopts the aforementioned reliable insulating film 120 fixing structure, it ensures that a single battery cell 100 will not experience displacement or short-circuit risk within the casing due to loosening of the insulating film 120, thereby making the entire battery pack structure more stable, with higher safety performance and a longer service life.

Claims

1. A battery cell, characterized in that, include: pole group; An insulating film is provided to cover the outer wall of the electrode assembly, and the insulating film is provided with an adhesive window through which a portion of the outer wall of the electrode assembly is exposed; The first adhesive element bonds the insulating film and the exposed outer wall of the electrode assembly through the adhesive window; The insulating film includes a first covering surface and a second covering surface. When the insulating film covers the outer wall of the electrode assembly, the first covering surface is provided with a first through hole, and the second covering surface is provided with a second through hole. The first through hole and the second through hole form the bonding window when the insulating film covers the outer wall of the electrode assembly. Wherein, the bonding overlap length between the first adhesive component and the first covering surface along the first direction is C1, and C1 satisfies: 3mm ≤ C1 ≤ 50mm; and / or, The bonding overlap length between the first adhesive and the second covering surface along the first direction is C2, and C2 satisfies: 3mm≤C2≤50mm.

2. The battery cell according to claim 1, characterized in that, The first adhesive element includes a first edge and a second edge that are distributed opposite to each other along a second direction; The bonding window includes a first inner wall and a second inner wall that are distributed opposite to each other along the second direction; Both the first edge and the second edge are located between the first inner wall and the second inner wall; A first gap is formed between the first edge and the first inner wall, the length of the first gap along the second direction being D1, wherein D1 satisfies: 1mm ≤ D1 ≤ 3mm; and / or, A second gap is formed between the second edge and the second inner wall, and the length of the second gap along the second direction is D2, wherein D2 satisfies: 1mm≤D2≤3mm.

3. The battery cell according to claim 1, characterized in that, The electrode group includes multiple sub-electrode groups, which are distributed along the first direction. The length of a single sub-electrode group along the first direction is A3, and the total length of the bonding window along the first direction is L1. A3 and L1 satisfy: L1≥0.25A3.

4. The battery cell according to claim 1, characterized in that, The battery cell also includes: The second adhesive is bonded to the side of the first adhesive, the first covering surface, and the second covering surface that is away from the electrode assembly, and the second adhesive completely covers the first adhesive and the adhesive window.

5. The battery cell according to claim 4, characterized in that, The bonding window includes a first inner wall and a second inner wall that are distributed opposite to each other along the second direction; the second adhesive includes a fifth edge and a sixth edge that are distributed opposite to each other along the second direction; The distance between the first inner wall and the fifth edge along the second direction is H1, wherein H1 satisfies: 3mm ≤ H1 ≤ 50mm; and / or, The distance between the second inner wall and the sixth edge along the second direction is H2, and H2 satisfies: 3mm≤H2≤50mm.

6. The battery cell according to claim 1, characterized in that, The battery cell also includes: A housing, wherein the length of the inner cavity of the housing along a third direction is M; The pole group includes an inlet portion and a main body portion distributed along the second direction, both of which are disposed within the housing; The total length of the inlet portion and the insulating film covering the outer wall of the inlet portion along the third direction is N1. N1 and M satisfy: 0.5mm≤(M-N1) / 2≤5mm, so that the inlet portion guides the main body portion into the housing.

7. The battery cell according to claim 6, characterized in that, The length of the main body and the insulating film covering the outer wall of the main body along the third direction is N2, and N2 and M satisfy: 93.75%≤N2 / M≤101.25%.

8. The battery cell according to claim 6, characterized in that, The length of the pole group along the second direction is S, and the length of the housing portion along the second direction is R. R and S satisfy: 0 < R ≤ 0.25S.

9. The battery cell according to claim 1, characterized in that, The bonding window includes a plurality of sub-windows spaced apart along the first direction.

10. A battery pack, characterized in that, include: shell; A plurality of battery cells as described in any one of claims 1 to 9, wherein all of the plurality of battery cells are disposed within the housing.

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