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, and the battery cell comprises a pole group and a packaging film. According to the battery cell with the structure, the edge folding structure comprises the first bending section, the second bending section and the third bending section, the second bending section is bent back to the pole group, and the third bending section is positioned between the first bending section and the second bending section, so that the cutting edge at the end part of the third bending section is far away from the side surface of the packaging main body, and the cutting edge is prevented from damaging the outer surface of the packaging main body; the integrity of the packaging film can be effectively ensured, and the sealing performance of the packaging film and the safety performance of the battery cell are ensured. And the end part of the third bending section is integrally positioned on the inner side of the space defined by the first bending section and the third bending section, so that external water vapor can be effectively prevented from entering the packaging film from the end part of the third bending section, and the sealing performance of the packaging film can be effectively improved. Meanwhile, the overlapping part is arranged, so that deformation of the extension part and the overlapping part can be effectively prevented, and the stability of the overall structure of the battery cell can be improved.

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 soft-pack battery and battery pack to solve the problem that the cut edges of the encapsulation film of the prior art are easily damaged on the outer surface of the encapsulation film.

[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 outward from the electrode assembly. The folded edge structure includes a stacked segment, a first bent segment, a second bent segment, and a third bent segment arranged sequentially. The stacked segment bends towards the top of the extension. The first bent segment is vertically or obliquely disposed on the stacked segment. The second bent segment bends towards the side of the first bent segment opposite to the electrode assembly. The third bent segment bends towards the first bent segment and is located between the first bent segment and the second bent segment.

[0007] Beneficial effects: The battery cell with this structure has a folded edge structure including a first bending section, a second bending section, and a third bending section, forming a three-layer folded edge. The second bending section bends away from the electrode group, and the third bending section is located between the first and second bending sections. This ensures that the cut edge at the end of the third bending section is away from the side of the encapsulation body, preventing the cut edge from damaging the outer surface of the encapsulation body. This effectively ensures the integrity of the encapsulation film, guarantees the sealing of the encapsulation film, and ensures the safety performance of the battery cell.

[0008] The end of the third bend is located between the first bend and the third bend, that is, the end of the third bend is entirely located inside the space enclosed by the first bend and the third bend. This arrangement can effectively prevent external moisture from entering the encapsulation film from the end of the third bend, thereby effectively improving the sealing performance of the encapsulation film.

[0009] The cell's folded edge structure also includes a laminating section, which is located at the top of the extension to form a double-layer structure at the bottom of the three-layer fold. This effectively improves 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 top surface of the second bend and the encapsulation body. The overall strength of the extension and the laminating section is improved, and their overall resistance to deformation is enhanced. This effectively prevents deformation of the extension and the laminating section and improves the stability of the overall cell structure.

[0010] 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.

[0011] In one alternative embodiment, the extension extends beyond the side of the encapsulation body by a length D1, where 1mm ≤ D1 ≤ 6mm.

[0012] Beneficial effects: This design provides sufficient bending space for the overlapping section, improving the convenience of bending operations; at the same time, D1≤6mm 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, making it easy to bend; at the same time, D2≤D1-0.5mm can prevent the length of the overlapping section from exceeding the length of the extension extending out of the side of the encapsulation body, ensuring that the side of the overlapping section facing the encapsulation film can be separated from the side of the encapsulation film after bending.

[0015] In one optional embodiment, the angle between the extension and the first bent segment is θ, where 45°≤θ≤120°.

[0016] Beneficial effects: It can effectively prevent the folded edge structure from tilting too far outward or towards the electrode group, and can reduce the space occupied by the folded edge structure in the width direction of the cell, making the overall structure of the cell more compact.

[0017] In one optional embodiment, the first bending segment is perpendicularly disposed on the overlapping segment, and the second bending segment and the third bending segment are both parallel to the first bending segment.

[0018] In one alternative implementation, the top of the folded edge structure does not extend beyond the plane containing the top surface of the battery cell.

[0019] In one optional embodiment, the encapsulation body is provided with a groove, the electrode group 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;

[0020] Alternatively, 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.

[0021] In one alternative embodiment, along the thickness direction of the battery cell, the length of the second bending segment is less than the length of the first bending segment, and the length of the third bending segment is less than the length of the second bending segment.

[0022] 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

[0023] 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.

[0024] Figure 1 This is a side view of a battery cell in the related art;

[0025] Figure 2 This is a side view of another type of battery cell in the related technology;

[0026] Figure 3 This is a three-dimensional structural diagram of a battery cell in related technologies;

[0027] Figure 4 This is a three-dimensional structural diagram of another type of battery cell in the related technology;

[0028] Figure 5 This is a side view of a battery cell according to an embodiment of the present utility model;

[0029] Figure 6 for Figure 5 Enlarged view of part A in the middle;

[0030] Figure 7 for Figure 5 Enlarged view of part A in the middle;

[0031] Figure 8This is a side view of another type of battery cell according to an embodiment of the present utility model.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1' Encapsulation film; 11' Encapsulation body; 12' Encapsulation area; 2' Positive electrode tab; 3' Negative electrode tab;

[0034] 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; 1224. Third bending section. Detailed Implementation

[0035] 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.

[0036] like Figures 3 to 5 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.

[0037] like Figures 1 to 4 As 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 located 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'. Because the folded edge is prone to returning to its original position and curling up after bending, it will curl up towards the side of the packaging body 11'. The cut edge is located at the end of the folded edge. After the cut edge curls up, 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. The battery cell includes a positive electrode tab 2' and a negative electrode tab 3'.

[0038] The following is combined with Figures 5 to 8 The following describes embodiments of the present invention.

[0039] According to an embodiment of the present invention, a battery cell is provided, including an electrode assembly and an encapsulation film 1. 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 from the electrode assembly. The folded edge structure 122 includes a stacked section 1221, a first bent section 1222, a second bent section 1223, and a third bent section 1224 arranged sequentially. The stacked section 1221 bends towards the top of the extension 121. The first bent section 1222 is vertically or obliquely disposed on the stacked section 1221. The second bent section 1223 bends towards the side of the first bent section 1222 opposite to the electrode assembly. The third bent section 1224 bends towards the first bent section 1222 and is located between the first bent section 1222 and the second bent section 1223. The end of the third bending segment 1224 has a cut edge.

[0040] The battery cell with this structure has a folded edge structure 122 including a first bending segment 1222, a second bending segment 1223, and a third bending segment 1224. That is, the folded edge structure 122 forms a three-layer folded edge. The second bending segment 1223 bends away from the electrode group, and the third bending segment 1224 is located between the first bending segment 1222 and the second bending segment 1223, so that the cut edge at the end of the third bending segment 1224 is away from the side of the encapsulation body 11, preventing the cut edge from damaging the outer surface of the encapsulation body 11. This can effectively ensure the integrity of the encapsulation film 1, and ensure the sealing performance of the encapsulation film 1 and the safety performance of the battery cell.

[0041] Two layers of encapsulation film 1 are provided at the encapsulation area 12. The two layers of encapsulation film 1 are heat-pressed together to form an encapsulation line. The end of the third bending section 1224 is located between the first bending section 1222 and the third bending section 1224. That is, the end of the third bending section 1224 is entirely located inside the space enclosed by the first bending section 1222 and the third bending section 1224. This arrangement can effectively prevent external moisture from entering the encapsulation film 1 from the end of the third bending section 1224, thereby effectively improving the sealing performance of the encapsulation film 1.

[0042] 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 stacking section 1221. The stacking section 1221 is located at the top of the extension 121 to form a double-layer structure at the bottom of the three-layer folded edge, which can effectively improve the overall strength of the extension 121 and the stacking 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 stacking section is improved, and its overall resistance to deformation is improved, which can effectively prevent the extension 121 and the stacking section from deforming and improve the stability of the overall battery cell structure.

[0043] 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.

[0044] 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 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 and the overlapping section 1221.

[0045] In some embodiments, the overlapping section 1221 can be bonded and fixed to the top surface of the extension to prevent the overlapping section 1221 from deforming and warping.

[0046] 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 third bending segment 1224, then bent downwards sequentially to form the second bending segment 1223 and the first bending segment 1222, and finally bent upwards to form the overlapping segment 1221. The length of the extension 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≤6mm provides sufficient bending space for the overlapping part and improves the convenience of bending operation; at the same time, D1≤6mm 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.

[0047] 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, ensuring that the overlapping section 1221 has sufficient length to facilitate bending the overlapping section 1221; at the same time, D2≤D1-0.5mm can prevent the length of the overlapping section 1221 from being greater than the length of the extension portion 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.

[0048] In some embodiments, such as Figure 6 As shown, the angle between the extension and the first bending section 1222 is θ, 45°≤θ≤120°, that is, the angle between the entire folded structure 122 and the extension is between 45° and 120°. The angle between the two is within this range, which can effectively prevent the folded structure 122 from tilting too far outward from the electrode group or tilting too far towards the electrode group. It can reduce the space occupied by the folded structure 122 in the width direction of the cell, making the overall structure of the cell more compact.

[0049] 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 and the third bending segment 1224 are 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.

[0050] In some embodiments, the top of the folded edge structure 122 does not exceed the plane where the top surface of the battery cell is located. This arrangement can prevent the folded edge structure 122 from extending beyond the top surface of the battery cell and prevent the folded edge structure 122 from occupying additional space outside the thickness range of the battery cell, thereby ensuring the compactness in the thickness direction of the battery cell and improving the volumetric energy density of the battery cell.

[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 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 and reduce the space occupied by the cell in its thickness direction.

[0052] In other embodiments, such as Figure 8 As shown, the encapsulation body 11 has two grooves, the electrode group is located in the grooves, and the encapsulation area 12 is located in the middle area of ​​the thickness direction of the battery cell. At this time, the folded edge structure 122 is bent towards the upper or lower part of the battery cell, and the end of the folded edge structure 122 does not exceed the top or bottom surface of the battery cell.

[0053] like Figure 6 and Figure 7 As shown, in some embodiments, along the thickness direction of the battery cell, the length of the second bending segment 1223 is less than the length of the first bending segment 1222. This arrangement facilitates bending the second bending segment 1223 and also allows the bent second bending segment 1223 to be spaced apart from the top surface of the overlapping segment 1221. Similarly, the length of the third bending segment 1224 is less than the length of the second bending segment 1223. This arrangement facilitates bending the third bending segment 1224 and also allows the end of the bent third bending segment 1224 to be spaced apart from the area between the first bending segment 1222 and the second bending segment 1223. Figure 6 As shown, the length of the second bend segment 1223 is L2, and the length of the third bend segment 1224 is L3.

[0054] 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 tab is located at one end along the length of the battery cell, while in other embodiments, the electrode tabs are located at both ends along the length of the battery cell.

[0055] According to an embodiment of the present invention, another aspect provides a battery pack including the cells of any of the above.

[0056] In this battery pack structure, the cell's folded edge structure 122 forms a three-layer folded edge, so that the cut edge at the end of the third bending segment 1224 is away from the side of the encapsulation body 11, preventing the cut edge from damaging the outer surface of the encapsulation body 11. This effectively ensures the integrity of the encapsulation film 1, the sealing performance of the encapsulation film 1, and the safety performance of the cell, thereby ensuring the safety performance of the battery pack. Furthermore, the end of the third bending segment 1224 is entirely located inside the space enclosed by the first bending segment 1222 and the third bending segment 1224, which effectively prevents external moisture from entering the encapsulation film 1 from the end of the third bending segment 1224, further ensuring the safety performance of the battery pack.

[0057] 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 outward from the electrode assembly. The folded edge structure includes a stacked segment, a first bent segment, a second bent segment, and a third bent segment arranged sequentially. The stacked segment bends towards the top of the extension. The first bent segment is vertically or obliquely disposed on the stacked segment. The second bent segment bends towards the side of the first bent segment opposite to the electrode assembly. The third bent segment bends towards the first bent segment and is located between the first bent segment and the second bent segment.

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 ≤ 6mm.

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 angle between the extension and the first bent section is θ, where 45°≤θ≤120°.

6. The battery cell according to claim 5, characterized in that, The first bending segment is perpendicular to the overlapping segment, and the second bending segment and the third bending segment are both parallel to the first bending segment.

7. The battery cell according to claim 6, characterized in that, The top of the folded edge structure does not exceed the plane containing the top surface of the battery cell.

8. The battery cell according to claim 7, characterized in that, The encapsulation body has a groove, the electrode group 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; Alternatively, 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.

9. The battery cell according to claim 8, characterized in that, Along the thickness direction of the battery cell, the length of the second bending segment is less than the length of the first bending segment, and the length of the third bending segment is less than the length of the second bending segment.

10. A battery pack, characterized in that, The battery cell includes any one of claims 1 to 9.

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