Battery cell and battery pack
By designing a folded edge structure on the encapsulation film of the pouch cell, including overlapping and bending sections, the problem of scratches on the cut edge of the encapsulation film is solved, the sealing and safety of the cell are improved, and the compactness and energy density of the cell are increased.
Patent Information
- Application Number
- CN202423037297.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-10
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2034-12-10
AI Technical Summary
The sharp edges of the encapsulation film at the cut edge of the soft-pack battery cell can easily scratch the outer surface of the encapsulation film, affecting the sealing performance and safety performance.
The design employs a folded edge structure, including an overlapping section, a first bending section, and a second bending section. The second bending section bends away from the electrode group, keeping the cut edge away from the side of the encapsulation body. The overlapping section forms a double-layer structure to enhance the overall strength.
It effectively prevents damage to the encapsulation film, ensures sealing and safety performance, and improves the compactness and volumetric energy density of the battery cell.
Smart Images
Figure CN223797411U_ABST
Abstract
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] A pouch cell consists of an electrode assembly and a sealing film. The electrode assembly is encapsulated within the sealing film. When a pouch cell undergoes secondary encapsulation, the sealing film is cut, resulting in sharp edges at the cut edges. When these cut edges are bent, the sealing film near the electrode assembly may scratch the outer surface of the sealing film, thus affecting the sealing performance of the pouch cell and consequently its safety performance. Utility Model Content
[0003] In view of this, the present invention provides a solution to the problem that the cut edges of the encapsulation film of the soft-pack battery are prone to damage to the outer surface of the encapsulation film in the prior art.
[0004] In a first aspect, this utility model provides a battery cell, comprising:
[0005] pole group;
[0006] An encapsulation film includes an encapsulation body and an encapsulation area. The encapsulation body covers the outside of the electrode assembly, and the encapsulation area is located outside the electrode assembly. The encapsulation area includes an extension and a folded edge structure. The extension extends toward the outside of the electrode assembly. The folded edge structure includes a stacked section, a first bending section, and a second bending section arranged sequentially. The stacked section bends toward one side of the extension. The first bending section is vertically or obliquely arranged on the stacked section. The second bending section bends toward the side of the first bending section opposite to the electrode assembly.
[0007] Beneficial effects: This cell structure features a folded edge structure including a first bending section and a second bending section. The second bending section bends away from the electrode group, meaning it bends outwards. This ensures that the cut edge at the end of the third bending section is away from the side of the encapsulation body, preventing damage to the outer surface of the encapsulation body. This effectively guarantees the integrity of the encapsulation film, ensuring its sealing performance and the safety of the cell. The first and second bending sections form two folds. While preventing damage to the side of the encapsulation body from the cut edge at the end of the second bending section, the overall folded edge structure occupies less space in the width direction of the cell, improving its compactness and volumetric energy density.
[0008] Because the folded structure formed after bending the encapsulation area is prone to deformation, reset, and springing back, related technologies require the use of tape to adhere the folded structure to the top surface of the encapsulation body. The tape extends upwards from the bottom surface of the encapsulation body to the side of the folded structure, and then to the top surface of the encapsulation body. The tape applies tension towards the extension, making it easy for the extension to bend towards the side of the encapsulation film. The folded structure of the battery cell in this structure also includes a laminating section, which is set on one side of the extension to form a double-layer structure at the bottom of the two folds. This can effectively improve the overall strength of the extension and the laminating section. After the tape is attached to the bottom of the extension, it extends sequentially to the second bending section and the top surface of the encapsulation body. The overall strength of the extension and the laminating section is improved, and its overall resistance to deformation is enhanced, which can effectively prevent the deformation of the extension and the laminating section and improve the stability of the overall battery cell structure.
[0009] In one alternative embodiment, the extension is parallel to the large surface of the pole group, and the overlapping section is parallel to the extension.
[0010] Beneficial effects: This design allows for a more compact encapsulation structure, thereby reducing the cell size and increasing its volumetric energy density. The parallel alignment of the lamination section and the extension effectively ensures the structural strength of both.
[0011] In one alternative embodiment, the extension extends beyond the side of the encapsulation body by a length D1, where 1mm ≤ D1 ≤ 5mm.
[0012] Beneficial effects: This design provides sufficient bending space for the overlapping section, improving the convenience of bending operations; at the same time, D1≤5mm can avoid excessive extension length of the extension section, which would waste space and ensure the compactness of the overall cell structure.
[0013] In one optional embodiment, the length of the overlapping segment is D2, where 0.5mm ≤ D2 ≤ D1 - 0.5mm.
[0014] Beneficial effects: This design ensures that the overlapping section has sufficient length to facilitate bending; on the other hand, D2≤D1-0.5mm prevents the length of the overlapping section from exceeding the length of the extension extending out of the packaging body, ensuring that the side of the overlapping section facing the packaging film can be separated from the side of the packaging film after bending.
[0015] In one alternative embodiment, the first bent segment is perpendicularly disposed on the overlapping segment, and the second bent segment is parallel to the first bent segment.
[0016] Beneficial effects: This setup can improve the compactness of the folded edge structure and reduce the space occupied by the encapsulation area.
[0017] In one optional embodiment, the encapsulation body has a groove, the electrode assembly is disposed in the groove, the encapsulation area is disposed on one side of the cell thickness direction, the cell thickness is H, and the extension portion and the folded edge structure extend along the cell thickness direction for a length of L1, where L1≤H.
[0018] Beneficial effect: This design prevents the top of the folded edge structure from extending beyond the top surface of the battery cell, reducing the space occupied by the battery cell in its thickness direction.
[0019] In one optional embodiment, the second bending segment extends along the thickness direction of the battery cell for a length of L2, where 0.5L1≤L2≤L1-0.5mm.
[0020] Beneficial effects: 0.5L1≤L2 ensures that the second bending segment has sufficient length, thus guaranteeing ease of bending the second bending segment. At the same time, L2≤L1-0.5mm ensures that the bottom end of the second bending segment is separated from the overlapping segment after bending, preventing the second bending segment from contacting and damaging the overlapping segment.
[0021] In one alternative implementation, 2mm ≤ H ≤ 15mm.
[0022] Beneficial effects: This design ensures the depth of the groove, allowing it to accommodate a sufficiently thick electrode assembly and guaranteeing the cell capacity. At the same time, it prevents the groove from being too deep, which could affect the overall strength of the encapsulation film. A moderate groove depth ensures the strength of the encapsulation film, thereby guaranteeing its sealing performance.
[0023] In one optional embodiment, the encapsulation body has two grooves, the electrode assembly is disposed in the grooves, and the encapsulation area is disposed in the middle region of the cell in the thickness direction.
[0024] Secondly, this utility model also provides a battery pack, including the battery cell described in any of the above descriptions. The battery pack includes the battery cell and has the same technical effects as the battery cell, which will not be repeated here. Attached Figure Description
[0025] 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.
[0026] Figure 1 This is a side view of a battery cell in the related art;
[0027] Figure 2This is a side view of another type of battery cell in the related technology;
[0028] Figure 3 This is a three-dimensional structural diagram of a battery cell in related technologies;
[0029] Figure 4 This is a three-dimensional structural diagram of another type of battery cell in the related technology;
[0030] Figure 5 This is a side view of a battery cell according to an embodiment of the present utility model;
[0031] Figure 6 for Figure 5 Enlarged view of part A in the middle;
[0032] Figure 7 for Figure 5 Enlarged view of part A in the middle;
[0033] Figure 8 This is a side view of another type of battery cell according to an embodiment of the present utility model.
[0034] Explanation of reference numerals in the attached figures:
[0035] 1. Encapsulation film; 11. Encapsulation body; 12. Encapsulation area; 121. Extension; 122. Folded edge structure; 1221. Overlapping section; 1222. First bending section; 1223. Second bending section. Detailed Implementation
[0036] 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.
[0037] like Figures 3 to 6 As shown, the x-axis is called the length direction of the battery cell, the y-axis is called the width direction of the battery cell, and the z-axis is called the thickness direction of the battery cell. The upper part of the z-axis is called the upper part of the battery cell, and the lower part of the z-axis is called the lower part of the battery cell. The large surface of the battery cell facing upward is its top surface, and the large surface of the battery cell facing downward is its bottom surface.
[0038] like Figures 1 to 4As shown, the battery cell in the related technology includes an electrode assembly and a packaging film 1'. The packaging film 1' includes a packaging body 11' and a packaging area 12'. The packaging body 11' has a groove, the electrode assembly is disposed in the groove, and the packaging area 12' is located outside the electrode assembly. The outer edge of the packaging area 12' is a cut edge. The packaging area 12' is bent towards the side of the packaging body 11' to form a folded edge. Then, the entire packaging area 12' is bent towards the side of the packaging body 11', with the folded edge facing the side of the packaging body 11'. Since the folded edge is prone to returning to its original position and lifting after bending, that is, the folded edge will lift towards the side of the packaging body 11'. The cut edge is located at the end of the folded edge. After the cut edge lifts, it is easy to scratch the side of the packaging body 11', thereby affecting the overall sealing performance of the packaging film 1' and the safety performance of the battery cell.
[0039] The following is combined Figures 5 to 8 The following describes embodiments of the present invention.
[0040] According to an embodiment of the present invention, a battery cell is provided, comprising an electrode assembly and an encapsulation film 1.
[0041] The encapsulation film 1 includes an encapsulation body 11 and an encapsulation region 12. The encapsulation body 11 covers the electrode assembly, and the encapsulation region 12 is located outside the electrode assembly. The encapsulation region 12 includes an extension 121 and a folded edge structure 122. The extension 121 extends outward toward the electrode assembly. The folded edge structure 122 includes a stacked section 1221, a first bent section 1222, and a second bent section 1223 arranged sequentially. The stacked section 1221 is bent toward one side of the extension 121. The first bent section 1222 is vertically or obliquely arranged on the stacked section 1221. The second bent section 1223 is bent toward the side of the first bent section 1222 that is opposite to the electrode assembly. The end of the second bent section 1223 has a cut edge.
[0042] The battery cell with this structure has a folded edge structure 122, which includes a first bending segment 1222 and a second bending segment 1223. The second bending segment 1223 bends away from the electrode group, that is, it bends outward so that the cut edge at the end of the third bending segment is away from the side of the encapsulation body 11. This prevents the cut edge from damaging the outer surface of the encapsulation body 11, effectively ensuring the integrity of the encapsulation film 1, and guaranteeing the sealing performance of the encapsulation film 1 and the safety performance of the battery cell. The first bending segment 1222 and the second bending segment 1223 form two folds. While preventing the cut edge at the end of the second bending segment from damaging the side of the encapsulation body 11, the folded edge structure 122 occupies less space in the width direction of the battery cell, which can improve the compactness of the battery cell and increase its volumetric energy density.
[0043] Because the folded edge structure 122 formed after the encapsulation area 12 is bent is prone to deformation, reset, and springing open, related technologies require the use of tape to adhere the folded edge structure 122 to the top surface of the encapsulation body 11. The tape extends upward from the bottom surface of the encapsulation body 11 to the side of the folded edge structure 122, and then to the top surface of the encapsulation body 11. The tape applies tension towards the extension 121, making it easy for the extension 121 to bend towards the side of the encapsulation film 1. The folded edge structure 122 of the battery cell in this structure also includes a laminating section 1221. The laminating section 1221 is disposed on one side of the extension 121 to form a double-layer structure at the bottom of the two folds, which can effectively improve the overall strength of the extension 121 and the laminating section. After the tape is attached to the bottom of the extension 121, it extends sequentially to the second bending section and the top surface of the encapsulation body 11. The overall strength of the extension 121 and the laminating section is improved, and its overall resistance to deformation is improved, which can effectively prevent the extension 121 and the laminating section from deforming and improve the stability of the overall battery cell structure.
[0044] Alternatively, in some embodiments, such as Figures 5 to 8 As shown, the extension 121 is parallel to the large surface of the electrode assembly, and the lamination section 1221 is parallel to the extension 121. This arrangement makes the structure of the encapsulation region 12 more compact, thereby reducing the volume of the battery cell and increasing its volumetric energy density. The parallelism between the lamination section 1221 and the extension 121 effectively ensures the structural strength of both.
[0045] like Figures 5 to 7 As shown, the overlapping section 1221 is attached to the top surface of the extension 121, and there is an arc-shaped bend between the extension 121 and the overlapping section 1221. The overlapping section 1221 is attached to the top surface of the extension 121, which can further improve the overall strength of the extension 121 and the overlapping section 1221.
[0046] An arc-shaped bending section is provided between the overlapping section 1221 and the first bending section 1222, and between the first bending section 1222 and the second bending section 1223. This arrangement allows for a smooth transition at the bends of each section and ensures the strength of the partition after bending.
[0047] In some embodiments, the overlapping section 1221 is bonded and fixed to the top surface of the extension 121 to prevent the overlapping section 1221 from deforming and warping.
[0048] Before bending, the encapsulation area 12 is in a horizontally extended state. When bending the edge structure 122, it can first be bent downwards to form the second bending segment 1223, then bent downwards to form the first bending segment 1222, and finally bent upwards to form the overlapping segment 1221. The length of the extension 121 extending beyond the side of the encapsulation body 11 is D1. If the value of D1 is too small, the end of the extension 121 will be too close to the side of the encapsulation film 1, which will make bending the overlapping part inconvenient. To avoid this problem, such as Figure 6 As shown, 1mm≤D1≤5mm provides sufficient bending space for the overlapping part and improves the convenience of bending operation; at the same time, D1≤5mm can avoid the extension length of the extension part 121 being too long and causing waste of space, and can ensure the compactness of the overall structure of the battery cell.
[0049] In some embodiments, such as Figure 6 As shown, the length of the overlapping section 1221 is D2, 0.5mm≤D2≤D1-0.5mm, and 0.5mm≤D2. On the one hand, this ensures that the overlapping section 1221 has sufficient length to facilitate bending the overlapping section 1221; on the other hand, D2≤D1-0.5mm can prevent the length of the overlapping section 1221 from being greater than the length of the extension 121 extending out of the side of the encapsulation body 11, ensuring that the side of the overlapping section 1221 facing the side of the encapsulation film 1 can be separated from the side of the encapsulation film after bending.
[0050] In some embodiments, such as Figure 6 and Figure 7 As shown, the first bending segment 1222 is vertically disposed on the overlapping segment 1221, and the second bending segment 1223 is parallel to the first bending segment 1222. This arrangement can improve the compactness of the folded edge structure 122 and reduce the space occupied by the encapsulation area 12.
[0051] In some embodiments, such as Figures 5 to 7 As shown, the encapsulation body 11 has a groove, the electrode group is located in the groove, and the encapsulation area 12 is located on one side of the cell thickness direction. The thickness of the cell is H, and the extension 121 and the folded edge structure 122 extend along the thickness direction of the cell by a length of L1, where L1≤H. This arrangement can prevent the top of the folded edge structure 122 from exceeding the top surface of the cell, thereby reducing the space occupied by the cell in its thickness direction.
[0052] In some embodiments, such as Figure 6 As shown, the length of the second bending segment extending along the thickness direction of the battery cell is L2, where 0.5L1≤L2≤L1-0.5mm. 0.5L1≤L2 ensures that the second bending segment 1223 has sufficient length, thus guaranteeing ease of bending. Simultaneously, L2≤L1-0.5mm ensures that the bottom end of the second bending segment 1223 is separated from the overlapping segment 1221 after bending, preventing the second bending segment 1223 from contacting and damaging the overlapping segment 1221.
[0053] In other embodiments, such as Figure 8 As shown, the encapsulation body 11 has two grooves, the electrode assembly is disposed in the grooves, and the encapsulation area 12 is disposed in the middle region of the cell in the thickness direction. At this time, the folded edge structure 122 is bent toward the upper or lower part of the cell, and the end of the folded edge structure 122 does not exceed the top or bottom surface of the cell.
[0054] In some embodiments, 2mm ≤ H ≤ 15mm. The groove is formed by stamping on the encapsulation film 1. The depth of the groove is approximately equal to the thickness of the battery cell. H satisfies 2mm ≤ H ≤ 15mm. This ensures that the groove depth can accommodate a sufficiently thick electrode assembly to guarantee the battery cell capacity, while also preventing the groove depth from being too deep and affecting the overall strength of the encapsulation film 1. The moderate groove depth ensures the strength of the encapsulation film 1, thereby guaranteeing its sealing performance.
[0055] Optionally, in some embodiments, the encapsulation film 1 comprises an aluminum-plastic film.
[0056] In some embodiments, such as Figure 5 and Figure 8 As shown, the folded edge structure 122 is disposed on both sides in the width direction of the battery cell.
[0057] like Figure 3 and Figure 4 As shown, the battery cell also includes a positive electrode tab and a negative electrode tab. In some embodiments, the electrode tabs are located at one end along the length of the battery cell, meaning both the positive and negative electrode tabs are located at one end along the length of the battery cell. In other embodiments, the electrode tabs are located at both ends along the length of the battery cell, meaning the positive and negative electrode tabs are located at opposite ends along the length of the battery cell.
[0058] According to an embodiment of the present invention, another aspect provides a battery pack including the cells of any of the above.
[0059] In this battery pack structure, the second bending segment 1223 bends away from the electrode group so that the cut edge at the end of the third bending segment is away from the side of the encapsulation body 11. This prevents the cut edge from damaging the outer surface of the encapsulation body 11, effectively ensuring the integrity of the encapsulation film 1 and guaranteeing the sealing performance of the encapsulation film 1 and the safety performance of the battery cell. The first bending segment 1222 and the second bending segment 1223 form two folds. While preventing the cut edge at the end of the second bending segment from damaging the side of the encapsulation body 11, the fold structure 122 occupies less space in the width direction of the battery cell, which can improve the compactness of the battery cell and increase the volumetric energy density of the battery cell, thereby improving the volumetric energy density of the battery pack.
[0060] 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 includes an encapsulation body and an encapsulation area. The encapsulation body covers the outside of the electrode assembly, and the encapsulation area is located outside the electrode assembly. The encapsulation area includes an extension and a folded edge structure. The extension extends toward the outside of the electrode assembly. The folded edge structure includes a stacked section, a first bending section, and a second bending section arranged sequentially. The stacked section bends toward one side of the extension. The first bending section is vertically or obliquely arranged on the stacked section. The second bending section bends toward the side of the first bending section opposite to the electrode assembly.
2. The battery cell according to claim 1, characterized in that, The extension is parallel to the large surface of the pole group, and the overlapping section is parallel to the extension.
3. The battery cell according to claim 2, characterized in that, The length of the extension extending beyond the side of the encapsulation body is D1, where 1mm ≤ D1 ≤ 5mm.
4. The battery cell according to claim 3, characterized in that, The length of the overlapping section is D2, where 0.5mm ≤ D2 ≤ D1 - 0.5mm.
5. The battery cell according to any one of claims 2 to 4, characterized in that, The first bent segment is perpendicularly disposed on the overlapping segment, and the second bent segment is parallel to the first bent segment.
6. The battery cell according to claim 5, characterized in that, The encapsulation body has a groove, the electrode assembly is disposed in the groove, the encapsulation area is disposed on one side of the cell thickness direction, the cell thickness is H, and the extension and the folded edge structure extend along the cell thickness direction for a length of L1, where L1≤H.
7. The battery cell according to claim 6, characterized in that, The second bending segment extends along the thickness direction of the battery cell for a length of L2, where 0.5L1≤L2≤L1-0.5mm.
8. The battery cell according to claim 6, characterized in that, 2mm≤H≤15mm.
9. The battery cell according to any one of claims 1 to 4, characterized in that, The encapsulation body has two grooves, the electrode group is disposed in the grooves, and the encapsulation area is disposed in the middle region of the cell in the thickness direction.
10. A battery pack, characterized in that, The battery cell includes any one of claims 1 to 9.