Battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell and a battery pack. Wherein the battery cell comprises a pole group; the packaging film wraps the outer side of the pole group and forms a packaging edge on the periphery of the pole group; the packaging edge located in the width direction of the pole group is bent to form a first bent edge, and the orthographic projection, facing the pole group, of the first bent edge is located on the side wall of the pole group. According to the utility model, the packaging edge positioned in the width direction of the pole group is bent, so that the overall structure of the battery cell is more compact, the size of the battery cell is reduced, the probability that the battery cell is in contact with other objects can be further reduced, and the situation that the packaging edge is damaged to lose the sealing performance is avoided.

Description

Technical Field

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

[0002] Pouch batteries are lithium-ion batteries that use flexible packaging materials, offering high energy density and good flexibility. To ensure complete isolation between the electrode assembly and the external environment, a common approach is to wrap the electrode assembly with a sealing film, followed by heat-sealing. However, after the heat-sealing process, the sealing edge formed by the film around the electrode assembly is relatively large, making it easily damaged by other objects around the battery. This can affect the battery's seal and cause electrolyte leakage. Utility Model Content

[0003] In view of this, the present invention provides a battery cell and battery pack to solve the problem that the packaging edge of soft-pack batteries is too large and easily damaged in related technologies.

[0004] In a first aspect, this utility model provides a battery cell, comprising:

[0005] pole group;

[0006] An encapsulation film is wrapped around the outside of the electrode assembly and forms an encapsulation edge around the electrode assembly; the encapsulation edge located in the width direction of the electrode assembly is bent to form a first bent edge, and the orthographic projection of the first bent edge toward the electrode assembly is located on the side wall of the electrode assembly.

[0007] Beneficial effects: This utility model bends the encapsulation edge located in the width direction of the electrode group, and makes the orthogonal projection of the first bent edge toward the electrode group located on the side wall of the electrode group, which can reduce the volume of the battery cell, make the overall structure of the battery cell more compact, thereby reducing the probability of other objects coming into contact with the battery cell and avoiding damage to the encapsulation edge and loss of sealing.

[0008] Secondly, because the volume of the battery cells has been reduced, more cells can be placed inside a battery pack of the same size and specifications. This change not only significantly improves the space utilization efficiency inside the battery pack, but also greatly increases the energy density of the battery pack itself.

[0009] Furthermore, because the volume of the battery cell has been reduced, during the assembly of multiple cells into a battery pack, the encapsulation edge of any cell in the width direction will not easily come into contact with the encapsulation film of the adjacent cell. This improves the safety and reliability of the battery pack during subsequent use.

[0010] In addition, by positioning the projection of the first bent edge toward the electrode assembly onto the side wall of the electrode assembly, the thickness of the battery cell is always kept within a preset thickness range, preventing the first bent edge from occupying the installation space in the thickness direction and ensuring the utilization rate of the internal space of the battery pack.

[0011] In one alternative embodiment, the encapsulation edge located in the width direction of the electrode group is bent again to form a second bent edge, the length of the second bent edge being greater than the length of the first bent edge, and the orthographic projection of the second bent edge toward the electrode group being located on the sidewall of the electrode group.

[0012] Beneficial Effects: By adding a second bending edge, this invention can further reduce the size of the encapsulation edge located in the width direction of the electrode assembly, thereby further reducing the volume of the battery cell. This not only allows the battery pack to accommodate more cells but also reduces the probability of the cells coming into contact with surrounding objects, ensuring the encapsulation film maintains excellent sealing performance. Secondly, making the length of the second bending edge greater than the length of the first bending edge improves the convenience of re-bending the encapsulation edge, reducing interference from the first bending edge during re-bending; it also allows more areas of the encapsulation edge to be located in the thickness direction of the electrode assembly instead of the width direction, thus reducing the size of the battery cell in the width direction and improving space utilization in the thickness direction. Furthermore, having the projection of the second bending edge onto the side wall of the electrode assembly ensures that the thickness of the battery cell remains within a preset range, preventing the second bending edge from occupying installation space in the thickness direction and ensuring efficient use of the internal space of the battery pack.

[0013] In one alternative embodiment, the first bent edge is located between the second bent edge and the pole group and is in contact with the second bent edge.

[0014] Beneficial effects: Since the edge of the encapsulation edge is located on the first bent edge, bending the encapsulation edge twice along the same bending direction allows the final position of the first bent edge to be between the second bent edge and the electrode assembly. This arrangement allows the sidewalls of the second bent edge and the electrode assembly to naturally form a protective structure that protects the first bent edge, reducing the probability of the edge of the encapsulation edge being damaged by objects around the cell. Furthermore, increasing the bending angle of the first bent edge, so that the first and second bent edges fit together, can further reduce the size of the encapsulation edge in the width direction of the electrode assembly; on the other hand, it can prevent the first bent edge from damaging the electrode assembly or the encapsulation film on the electrode assembly during the forming process of the second bent edge.

[0015] In one optional embodiment, the bending angle of the second bent edge is A, and the range of A is 90°≤A≤180°.

[0016] Beneficial effects: This invention sets the bending angle A of the second bending edge within the range of 90° to 180°, allowing the second bending edge to be as close as possible to the sidewall of the electrode assembly, thereby reducing the size of the cell in its width direction. On the other hand, since the first bending edge can be located between the second bending edge and the electrode assembly, when the bending angle A of the second bending edge is between 90° and 180°, the exposed area of ​​the first bending edge can be reduced, effectively preventing the first bending edge from losing its sealing performance due to physical damage or environmental influences, thereby extending the service life of the cell.

[0017] In an alternative embodiment, the system further includes an adhesive tape, one end of which is connected to the side of the second bend away from the electrode assembly, and the other end of which is connected to the surface of the encapsulation film in the direction of the second bend.

[0018] Beneficial effects: This invention uses adhesive tape to fix the second bent edge to the electrode assembly, ensuring that the position of the second bent edge does not change during the use of the battery cell. This allows the battery cell to maintain a small size in its width direction and prevents the encapsulation edge from contacting surrounding objects. Furthermore, by attaching one end of the tape to the side of the second bent edge away from the electrode assembly and the other end to the surface of the encapsulation film in the direction of the second bent edge, the tensile force generated by the tape brings the end of the second bent edge connected to the first bent edge closer to the sidewall of the electrode assembly, thereby reducing the size of the battery cell in its width direction.

[0019] In one alternative embodiment, there are multiple tapes, and the multiple tapes are spaced apart along the length direction of the electrode group.

[0020] Beneficial Effects: Compared to a single tape, this invention, by using multiple tapes spaced apart along the length of the electrode assembly, can more effectively fix the position of the second bent edge, ensuring that the bending angle A of the second bent edge remains between 90° and 180°, maintaining the small size of the battery cell in its width direction. Furthermore, multiple tapes can share the stress, reducing the load on a single tape and thus lowering the risk of tape breakage. Secondly, as the tape is used for a longer period, the adhesive performance of the adhesive itself gradually decreases. If only one tape is used, it will be insufficient to fix the second bent edge. In contrast, this invention, by using multiple tapes to fix the second bent edge, allows multiple tapes to share the fixing task. Thus, even if the adhesive performance of one tape decreases, the remaining tapes can still provide sufficient fixing force, ensuring that the bending angle and position of the second bent edge do not change.

[0021] In one alternative embodiment, the tape has a size of 5 mm to 10 mm along the length of the battery cell.

[0022] Beneficial effects: Setting the tape size according to the above parameters ensures that the tape has good adhesive properties, that is, it can provide sufficient fixing force to ensure that the bending angle and position of the second bending edge will not change.

[0023] In one optional embodiment, the length of the unbent portion of the encapsulation edge in the width direction of the cell is B, and the range of B is 0.5mm≤B≤2mm.

[0024] Beneficial effects: This utility model controls the length B of the unbent portion of the encapsulation edge to between 0.5mm and 2mm. On the one hand, it can prevent the size of the unbent edge from being too small, which would cause the encapsulation film on the electrode assembly to be pulled during the bending process of the second bending edge, thus ensuring the integrity and sealing of the encapsulation film. On the other hand, it can prevent the size of the unbent edge from being too large, which would affect the size of the cell in its width direction.

[0025] In one alternative implementation, a transition fillet is formed at the bend position of the second bent edge.

[0026] Beneficial effects: By setting a transition fillet here, stress concentration can be avoided. In addition, during the manufacturing process, the transition fillet makes the bending process smoother, reducing the possibility of the encapsulation edge 201 cracking due to excessive local deformation during bending.

[0027] Secondly, the present invention also provides a battery pack, comprising: a plurality of the above-mentioned battery cells, wherein the free end of the first bent edge is inclined toward the direction of the side wall of the electrode group.

[0028] Beneficial Effects: Because the aforementioned battery cell reduces its width by bending its encapsulation edge, during the assembly of multiple cells into a battery pack, the encapsulation edge of any single cell will not easily contact the encapsulation film of an adjacent cell. This effectively reduces the probability of electrolyte leakage due to damage to the encapsulation film. Furthermore, the reduced width of the battery cell allows for the placement of more cells within a battery pack of the same size and specifications, improving the energy density and internal space utilization of the battery pack. Secondly, the free end of the first bent edge is inclined towards the sidewall of the electrode assembly, meaning the bending angle of the first bent edge is between 90° and 180°. Simultaneously, the distance between the free end of the first bent edge and the sidewall of the electrode assembly is also within a small range. This effectively reduces the width of the battery cell, making the overall structure more compact. In addition, the battery pack of this invention possesses other advantages of the aforementioned battery cell, which will not be elaborated upon here. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present utility model;

[0031] Figure 2 for Figure 1 A top view of the battery cell shown;

[0032] Figure 3 for Figure 1 A side view of the battery cell shown.

[0033] Figure 4 This is a schematic diagram of the structure of a battery cell from another perspective according to an embodiment of the present utility model;

[0034] Figure 5 for Figure 4 A magnified view of a portion of H in the diagram.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. Electrode assembly; 101. Sidewall; 2. Encapsulation film; 201. Encapsulation edge; 2011. First bending edge; 2012. Second bending edge; 3. Adhesive tape. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0038] In view of the problem that the packaging edge of soft-pack batteries is too large and easily damaged in related technologies, this utility model provides a battery cell and its battery pack.

[0039] The following is combined with Figures 1 to 5 The following describes embodiments of the present invention.

[0040] According to embodiments of the present invention, on the one hand, such as Figures 1 to 5 As shown, a battery cell is provided, including: an electrode group 1 and an encapsulation film 2.

[0041] Specifically, the encapsulation film 2 wraps around the outside of the electrode group 1 and forms an encapsulation edge 201 around the electrode group 1; the encapsulation edge 201 located in the width direction of the electrode group 1 is bent to form a first bent edge 2011, and the orthographic projection of the first bent edge 2011 toward the electrode group 1 is located on the side wall 101 of the electrode group 1.

[0042] In this embodiment, the encapsulation edge 201 located in the width direction of the electrode group 1 is bent, and the orthogonal projection of the formed first bent edge 2011 toward the electrode group 1 is located on the side wall 101 of the electrode group 1. This can reduce the volume of the battery cell, make the overall structure of the battery cell more compact, thereby reducing the probability of other objects coming into contact with the battery cell and preventing the encapsulation edge 201 from being damaged and losing its sealing performance.

[0043] Secondly, because the volume of the battery cells has been reduced, more cells can be placed inside a battery pack of the same size and specifications. This change not only significantly improves the space utilization efficiency inside the battery pack, but also greatly increases the energy density of the battery pack itself.

[0044] Furthermore, because the volume of the battery cell is reduced, during the assembly of multiple cells into a battery pack, the encapsulation edge 201 of any cell in the width direction will not easily contact the encapsulation film 2 of the adjacent cell. This improves the safety and reliability of the battery pack during subsequent use. In addition, by positioning the orthographic projection of the first bent edge 2011 toward the electrode group 1 onto the side wall 101 of the electrode group 1, the thickness of the battery cell itself is always kept within a preset thickness range, preventing the first bent edge 2011 from occupying the installation space in the thickness direction and ensuring the efficient utilization of the internal space of the battery pack.

[0045] It should be noted that the encapsulation film 2 in this embodiment is an aluminum-plastic film, which includes a nylon layer, an aluminum foil layer, and a polypropylene layer stacked sequentially. As can be seen, because the encapsulation film 2 contains an aluminum foil layer, after the encapsulation edge 201 is bent, the position of the first bent edge 2011 will not change significantly without the influence of other external forces. Therefore, the battery cell can remain in a small size state in the width direction for a long time.

[0046] According to one embodiment of the present invention, such as Figure 4 and Figure 5 As shown, the encapsulation edge 201 located in the width direction of the electrode group 1 is bent again to form a second bent edge 2012. The length of the second bent edge 2012 is greater than the length of the first bent edge 2011, and the orthographic projection of the second bent edge 2012 toward the electrode group 1 is located on the side wall 101 of the electrode group 1. In this embodiment, by adding the second bent edge 2012, the size of the encapsulation edge 201 located in the width direction of the electrode group 1 can be further reduced, thereby further reducing the volume of the battery cell. In this way, not only can more battery cells be accommodated inside the battery pack, but the probability of the battery cell coming into contact with surrounding objects can also be reduced, ensuring that the encapsulation film 2 can always have good sealing performance. Secondly, making the length of the second bending edge 2012 greater than the length of the first bending edge 2011 improves the ease of re-bending the encapsulation edge 201 and reduces the interference of the first bending edge 2011 during the re-bending process. Furthermore, it allows more areas on the encapsulation edge 201 to be located in the thickness direction of the electrode group 1, rather than the width direction. This not only reduces the size of the cell in the width direction but also improves the space utilization in the thickness direction. In addition, having the orthographic projection of the second bending edge 2012 onto the sidewall 101 of the electrode group 1 ensures that the cell's thickness remains within a preset range, preventing the second bending edge 2012 from occupying installation space in the thickness direction and ensuring efficient use of the battery pack's internal space.

[0047] It should be noted that the bending directions of the first bent edge 2011 and the second bent edge 2012 can be the same or different. For example, when the bending directions of the first bent edge 2011 and the second bent edge 2012 are different, after the second bent edge 2012 is formed, the first bent edge 2011 will be located on the side of the second bent edge 2012 away from the electrode group 1. When the bending directions of the first bent edge 2011 and the second bent edge 2012 are the same, the first bent edge 2011 will be located on the side of the second bent edge 2012 closer to the electrode group 1.

[0048] Furthermore, to further reduce the width dimension of the bend in the encapsulation edge 201, the surfaces of the first bend edge 2011 and the second bend edge 2012 can be made to fit together. This state is illustrated below with a specific example:

[0049] In one embodiment, such as Figure 5 As shown, the first bent edge 2011 is located between the second bent edge 2012 and the electrode group 1 and is in contact with the second bent edge 2012. Since the edge of the encapsulation edge 201 is located on the first bent edge 2011, bending the encapsulation edge 201 twice along the same bending direction allows the first bent edge 2011 to be finally positioned between the second bent edge 2012 and the electrode group 1. This arrangement allows the second bent edge 2012 and the sidewall 101 of the electrode group 1 to naturally form a protective structure that protects the first bent edge 2011, reducing the probability that the edge of the encapsulation edge 201 will be damaged by objects around the cell. Furthermore, by increasing the bending angle of the first bending edge 2011, the first bending edge 2011 and the second bending edge 2012 are brought into contact. On the one hand, this can further reduce the size of the encapsulation edge 201 located in the width direction of the electrode group 1; on the other hand, it can prevent the first bending edge 2011 from damaging the electrode group 1 or the encapsulation film 2 on the electrode group 1 during the forming process of the second bending edge 2012.

[0050] In addition, the first bent edge 2011 is located between the second bent edge 2012 and the electrode group 1, which can also prevent the edge of the encapsulation film 2 from contacting the negative electrode tab of other cells in the battery pack, thus avoiding an electrochemical reaction between them.

[0051] According to one embodiment of the present invention, such as Figure 5 As shown, the bending angle of the second bending edge 2012 is A, and the range of A is 90°≤A≤180°. In this embodiment, the bending angle A of the second bending edge 2012 is set between 90° and 180°, which allows the second bending edge 2012 to be as close as possible to the side wall 101 of the electrode group 1, thereby reducing the size of the cell in its width direction. On the other hand, since the first bending edge 2011 can be located between the second bending edge 2012 and the electrode group 1, when the bending angle A of the second bending edge 2012 is between 90° and 180°, the exposed area of ​​the first bending edge 2011 can be reduced, effectively preventing the first bending edge 2011 from losing its sealing performance due to physical damage or environmental influence, thereby extending the service life of the cell.

[0052] It should be noted that when the bending angle A of the second bending edge 2012 is 180°, this means that after bending, the second bending edge 2012 will adhere to the surface of the remaining unbent portion of the encapsulation edge 201. Furthermore, to avoid damage to the electrode assembly 1 during the bending process, the length of the unbent portion needs to be greater than the length of the second bending edge 2012.

[0053] According to one embodiment of the present invention, such as Figures 1 to 3 As shown, it also includes tape 3. One end of tape 3 is connected to the side of the second bent edge 2012 away from the electrode group 1, and the other end is connected to the surface of the encapsulation film 2 in the direction of the second bent edge 2012. In this embodiment, by fixing the second bent edge 2012 to the electrode group 1 with tape 3, it is possible to ensure that the position of the second bent edge 2012 does not change during the use of the battery cell, that is, it can keep the battery cell in a small size in its width direction and prevent the encapsulation edge 201 from contacting surrounding objects. In addition, by sticking one end of tape 3 to the side of the second bent edge 2012 away from the electrode group 1 and the other end of tape 3 to the surface of the encapsulation film 2 in the direction of the second bent edge 2012, the tensile force generated by tape 3 can be used to make the end of the second bent edge 2012 connected to the first bent edge 2011 closer to the side wall 101 of the electrode group 1, thereby reducing the size of the battery cell in its width direction.

[0054] According to one embodiment of the present invention, such as Figures 1 to 3 As shown, there are multiple adhesive tapes 3, spaced apart along the length of the electrode assembly 1. Compared to a single adhesive tape 3, this embodiment, by spaced multiple adhesive tapes 3 along the length of the electrode assembly 1, can more effectively fix the position of the second bending edge 2012, ensuring that the bending angle A of the second bending edge 2012 is always between 90° and 180°, maintaining the small size of the battery cell in its width direction. Furthermore, multiple adhesive tapes 3 can share the stress, reducing the load borne by a single adhesive tape 3, thereby reducing the risk of tape 3 breakage. Secondly, as the adhesive tape 3 is used for a longer period, the adhesive properties of the adhesive itself will gradually decrease. At this point, if only one adhesive tape 3 is used, it will be impossible to continue fixing the second bending edge 2012. In contrast, this embodiment uses multiple tapes 3 to fix the second bent edge 2012, allowing multiple tapes 3 to share the fixing task. Thus, even if the adhesive performance of one tape 3 decreases, the remaining tapes 3 can still provide sufficient fixing force to ensure that the bending angle and position of the second bent edge 2012 do not change.

[0055] According to one embodiment of this utility model, the tape 3 has a size of 5mm to 10mm along the length of the battery cell. Setting the tape size according to the above parameters ensures that the tape has good adhesive properties, that is, it can provide sufficient fixing force to ensure that the bending angle and position of the second bending edge do not change.

[0056] According to one embodiment of the present invention, such as Figure 5 As shown, the length of the unbent edge of the encapsulation edge 201 in the width direction of the cell is B, and the range of B is 0.5mm ≤ B ≤ 2mm. In this embodiment, the length B of the unbent edge of the encapsulation edge 201 is controlled between 0.5mm and 2mm. On the one hand, this can prevent the size of the unbent edge from being too small, which would cause the encapsulation film 2 on the electrode group 1 to be pulled during the bending process of the second bending edge 2012, thus ensuring the integrity and sealing of the encapsulation film 2. On the other hand, it can prevent the size of the unbent edge from being too large, which would affect the size of the cell in its width direction.

[0057] According to one embodiment of the present invention, a transition fillet is formed at the bending position of the second bending edge 2012. By setting a transition fillet at this location, stress concentration can be avoided. Furthermore, during processing, the transition fillet makes the bending process smoother, reducing the possibility of the encapsulation edge 201 breaking due to excessive local deformation during bending.

[0058] According to an embodiment of the present invention, another aspect provides a method for preparing a battery cell, comprising:

[0059] The encapsulation film 2 is wrapped around the outside of the electrode assembly 1 and the encapsulation film 2 is encapsulated to form an encapsulation edge 201.

[0060] The packaging edge 201 located in the width direction of the electrode group 1 is bent to form a first bent edge 2011;

[0061] Adjust the bending angle of the first bent edge 2011 so that the orthographic projection of the first bent edge 2011 toward the pole group 1 is located on the side wall 101 of the pole group 1.

[0062] In this embodiment, by encapsulating the outer side of the electrode assembly 1 with the encapsulation film 2, the electrode assembly 1 can be completely isolated from the external environment, providing a relatively safe and enclosed operating space for the electrode assembly 1. Subsequently, the encapsulation edge 201 on the encapsulation film 2 is bent, and the bending angle of the encapsulation edge 201 is adjusted to a reasonable range. This allows for a reduction in the width dimension of the battery cell without increasing the cell thickness, thereby improving the compactness of the battery cell structure.

[0063] According to one embodiment of the present invention, it includes:

[0064] A bending position larger than the length of the first bending edge 2011 is selected on the packaging edge 201, and the packaging edge 201 located in the width direction of the pole group 1 is bent again from the bending position to form the second bending edge 2012.

[0065] Adjust the bending angle of the second bent edge 2012 so that the orthographic projection of the second bent edge 2012 toward the pole group 1 is located on the side wall 101 of the pole group 1.

[0066] In this embodiment, a bending position larger than the length of the first bending edge 2011 is selected on the encapsulation edge 201 for a second bending. This avoids interference from the first bending edge 2011 on the second bending of the encapsulation edge 201, ensuring the smooth formation of the second bending edge 2012. Furthermore, it prevents more areas of the encapsulation edge 201 from extending into the width direction, thus reducing the size of the battery cell in the width direction. Subsequently, the bending angle of the second bending edge 2012 is adjusted to a reasonable range, further reducing the size of the battery cell in the width direction without increasing its thickness, thereby improving the compactness of the battery cell structure.

[0067] According to an embodiment of the present invention, another aspect provides a battery pack, including: a plurality of the aforementioned battery cells, wherein the free end of the first bent edge 2011 is inclined toward the sidewall 101 of the electrode assembly 1. Since the aforementioned battery cells reduce their width dimension by bending their encapsulation edge 201, during the assembly of the plurality of aforementioned battery cells into a battery pack, the encapsulation edge 201 of any battery cell in the width direction will not easily contact the encapsulation film 2 of an adjacent battery cell. Therefore, the probability of electrolyte leakage due to damage to the encapsulation film 2 can be effectively reduced. Furthermore, since the width dimension of the aforementioned battery cells is reduced, more battery cells can be placed inside a battery pack of the same size and specifications, improving the energy density of the battery pack and the space utilization rate inside the battery pack. Secondly, the free end of the first bent edge 2011 is inclined towards the side wall 101 of the electrode group 1, meaning that the bending angle of the first bent edge 2011 is also between 90° and 180°. Simultaneously, the distance between the free end of the first bent edge 2011 and the side wall 101 of the electrode group 1 is also within a small range. This effectively reduces the size of the cell in its width direction, making the overall structure of the cell more compact. Furthermore, the battery pack in this embodiment also possesses other advantages of the aforementioned cell, which will not be elaborated upon here.

[0068] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: pole group; An encapsulation film is wrapped around the outside of the electrode assembly and forms an encapsulation edge around the electrode assembly; The encapsulation edge located in the width direction of the electrode group is bent to form a first bent edge, and the orthographic projection of the first bent edge toward the electrode group is located on the side wall of the electrode group.

2. The battery cell according to claim 1, characterized in that, The encapsulation edge located in the width direction of the electrode group is bent again to form a second bent edge. The length of the second bent edge is greater than the length of the first bent edge, and the orthogonal projection of the second bent edge toward the electrode group is located on the side wall of the electrode group.

3. The battery cell according to claim 2, characterized in that, The first bent edge is located between the second bent edge and the pole group and is in contact with the second bent edge.

4. The battery cell according to claim 2, characterized in that, The bending angle of the second bent edge is A, and the range of A is 90°≤A≤180°.

5. The battery cell according to claim 3, characterized in that, It also includes an adhesive tape, one end of which is connected to the side of the second bent edge away from the electrode assembly, and the other end is connected to the surface of the encapsulation film in the direction of the second bent edge.

6. The battery cell according to claim 5, characterized in that, There are multiple tapes, and the multiple tapes are spaced apart along the length direction of the electrode group.

7. The battery cell according to claim 5, characterized in that, Along the length of the battery cell, the tape has a size of 5mm to 10mm.

8. The battery cell according to any one of claims 2 to 7, characterized in that, The length of the unbent portion of the encapsulation edge in the width direction of the cell is B, and the range of B is 0.5mm≤B≤2mm.

9. The battery cell according to any one of claims 2 to 7, characterized in that, A transition rounded corner is formed at the bend position of the second bent edge.

10. A battery pack, characterized in that, include: In any one of claims 1 to 9, the free end of the first bent edge is inclined toward the direction of the sidewall of the electrode group.

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