Battery cells and battery packs

Abstract

This invention relates to the field of battery cell technology and discloses a battery cell and battery pack. The battery cell of this invention includes an encapsulation film, an electrode assembly, an external positive electrode tab, and an external negative electrode tab. A first through-hole is provided on the inner side of the receiving groove of the encapsulation film, and second through-holes are provided on the electrode sheet and the separator. After the battery cell is assembled, the first and second through-holes communicate to form a vertically penetrating heat dissipation hole in the middle region of the battery cell. This significantly improves the heat dissipation effect in the internal region of the battery cell, thereby effectively improving the overall heat dissipation effect and enhancing the safety performance of the battery cell. Simultaneously, the internal electrode tab of the electrode sheet extends towards the second through-hole, and the external electrode tab connects to the internal electrode tab and is located within the first and second through-holes in the middle region of the battery cell. The external electrode tab does not occupy space outside the outer contour of the encapsulation film, which improves the compactness of the battery cell structure, reduces the space occupied by the battery cell, and makes it suitable for the small-volume battery requirements of mobile or wearable devices.

Description

Technical Field

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

[0002] Pouch batteries typically have tabs on one or both sides, and the tabs are all located on the outer periphery of the pouch battery. This results in a large overall space occupied by pouch batteries, which is not conducive to the miniaturization of pouch batteries and makes it difficult to meet the demand for small-sized batteries in mobile or wearable devices. Furthermore, the heat dissipation of existing pouch batteries is not good. Summary of the Invention

[0003] In view of this, the present invention provides a battery cell and a battery pack to solve the problems of large space occupation and poor heat dissipation of existing soft-pack batteries due to external tabs.

[0004] In a first aspect, the present invention provides a battery cell, comprising:

[0005] The encapsulation film includes a first encapsulation film and a second encapsulation film. At least one of the first encapsulation film and the second encapsulation film is provided with a receiving groove. The first encapsulation film and the second encapsulation film are provided with a first through hole inside the receiving groove. The first encapsulation film and the second encapsulation film are sealed together.

[0006] An electrode assembly is disposed within the receiving groove; the electrode assembly includes multiple electrode plates and a separator, the electrode plates including positive electrode plates and negative electrode plates; a through second hole is provided in the middle region of the positive electrode plate, the negative electrode plate and the separator; an internal positive electrode tab extends from the wall of the second through hole into the inside of the second through hole of the positive electrode plate, and an internal negative electrode tab extends from the wall of the second through hole into the inside of the second through hole of the negative electrode plate, the internal positive electrode tab and the internal negative electrode tab being spaced apart; the second through hole and the first through hole are vertically connected;

[0007] The device comprises an external positive electrode and an external negative electrode, wherein the external positive electrode is welded to the internal positive electrode and the external negative electrode is welded to the internal negative electrode. The internal positive electrode and the internal negative electrode are located within the first encapsulation film and the second encapsulation film, and one end of the external positive electrode and the external negative electrode are located within the first through hole and the second through hole. The external positive electrode and the external negative electrode are spaced apart.

[0008] Beneficial effects: In this cell structure, the inner side of the encapsulation film's receiving groove has a first through-hole, and the electrode and separator have second through-holes. After cell assembly, the first and second through-holes are connected to form a vertically continuous heat dissipation hole in the central region of the cell. This significantly improves the heat dissipation effect in the internal region of the cell, thereby effectively enhancing the overall heat dissipation performance and improving the cell's safety performance. Simultaneously, the internal tabs of the electrode extend towards the second through-hole, and the external tabs connect to the internal tabs and are located within the first and second through-holes in the central region of the cell. The external tabs do not occupy space outside the outer contour of the encapsulation film, improving the cell's compactness and reducing its footprint, making it suitable for the small-volume battery requirements of mobile or wearable devices.

[0009] In one optional embodiment, the first through hole and the second through hole are strip-shaped holes, and the internal positive electrode tab and the internal negative electrode tab are disposed opposite to each other on both sides of the length direction of the second through hole.

[0010] Beneficial effects: After the electrode sheets are cut, the internal positive and negative tabs extend parallel to the electrode sheets towards the inside of the second through hole. After stacking, the internal positive tab is located on one side of the length direction of the second through hole, and the internal negative tab is located on the other side. The structures of the positive and negative electrode sheets can be identical, facilitating the cutting and manufacturing of the positive and negative electrode sheets. After cutting, the internal tabs of the two sheets are stacked with their internal tabs facing each other, thus separating the internal positive and internal negative tabs along the length direction of the second through hole and preventing them from contacting each other and causing a short circuit. At the same time, the first and second through holes are strip-shaped, which helps to separate the external positive and external negative tabs along the length direction of the heat dissipation holes, reducing the risk of short circuits caused by contact between the external positive and external negative tabs.

[0011] In one alternative embodiment, the outer contours of the cross-sections of the electrode assembly and the electrode sheet are circular, and the shape of the receiving groove is adapted to the shape of the electrode assembly.

[0012] In one optional embodiment, both the first through-hole and the second through-hole are rectangular; the diameter of the electrode is D, the width of the second through-hole is W, the diameter of the encapsulation film is d, and the width of the first through-hole is w.

[0013] And / or,

[0014] Beneficial effects: This setting ensures the width of the second through hole, and the internal tab is placed inside the second through hole, thus ensuring the width of the internal tab and its current carrying capacity; at the same time, it can prevent the size of the second through hole from being too small, which would affect the heat dissipation of the inner area of ​​the cell. This design prevents the width of the second through hole from being too large, which would result in the size of the electrode body being too small. It ensures the area of ​​the electrode body, thereby guaranteeing the strength and volumetric energy density of the cell.

[0015] The width of the first through hole is slightly smaller than the width of the second through hole. The first through hole is located circumferentially inside the second through hole, so that the first encapsulation film and the second encapsulation film encapsulate the hole wall of the second through hole inside the encapsulation film. This design prevents the width of the first through hole from being too small, which would limit the size of the external tabs and thus affect their current carrying capacity; it also avoids the first through hole being too small, which would affect the heat dissipation of the battery cell. This design avoids making the width of the first through-hole too large, thus ensuring the volumetric energy density and overall strength of the battery cell.

[0016] In one optional embodiment, the second through hole is symmetrically arranged along the center line of the electrode, and the distance between the hole wall on one side of the length direction of the second through hole and the center line of the electrode is L1, 20mm≤L1≤60mm;

[0017] And / or, the first through hole is symmetrically arranged along the center line of the encapsulation film, and the distance between the edge of the sealing edge on one side of the length direction of the first through hole and the center line of the encapsulation film is l1, 18mm≤11≤58mm.

[0018] Beneficial effects: L1≥20mm, this setting can ensure that the second through hole has sufficient length, preventing the length of the second through hole from being too small and limiting the length of the internal electrode tab; at the same time, L1≤60mm, this setting can avoid the second through hole being too long, and prevent the electrode assembly from being affected by the length of the opening.

[0019] The length of the first through hole is 18mm≤11≤58mm. This setting can prevent the length of the first through hole from being too small, which would limit the size of the external tab and help ensure the current carrying capacity of the external tab. At the same time, it can prevent the size of the first through hole from being too large, which would affect the strength and volumetric energy density of the cell.

[0020] In one alternative implementation, prior to the welding of the internal tabs of all the electrodes, the length L2 extending from the internal tabs of the electrodes toward the centerline of the electrodes is [missing information].

[0021] And / or, the distance between the edge of the sealing edge of the first through hole on the side where the inner tab is located and the end of the outer tab facing the center line of the encapsulation film is l2.

[0022] Beneficial effect: L2≥10, this setting can ensure the extension length of the internal tabs and guarantee their current carrying capacity. Meanwhile... This can prevent the internal tabs from being too long and prevent the internal positive and negative tabs from overlapping after the plates are stacked.

[0023] l2≥8, this setting ensures the length of the external tabs and their current-carrying capacity. The external positive and negative tabs extend horizontally towards each other. This design prevents external tabs with opposite polarities from short-circuiting due to excessive length and overlapping.

[0024] In one alternative embodiment, before the internal tabs of all the electrodes are welded, the distance between the end of the internal tab of the electrode facing the center line of the electrode and the center line of the electrode is L3, where L3 ≥ 2 mm;

[0025] And / or, the distance between the end of the external tab facing the center line of the encapsulation film and the center line of the encapsulation film is l3, where l3 ≥ 2 mm.

[0026] In one optional embodiment, the end face of the inner wall of the receiving groove is provided with an inner edge extension extending toward the first through hole, and the end face of the outer wall of the receiving groove is provided with an outer edge extension extending outward, and an external electrode is provided on the inner edge extension; the first encapsulation film and the second encapsulation film are heat-sealed together, and the inner edge extension and the outer edge extension form a sealing area.

[0027] In one optional embodiment, the receiving groove is provided on one of the first encapsulation film and the second encapsulation film, and the other of the first encapsulation film and the second encapsulation film is sealed at the end of the encapsulation film provided with the receiving groove; the thickness of the battery cell is H, 2mm≤H≤15mm;

[0028] Alternatively, both the first encapsulation film and the second encapsulation film are provided with the receiving groove, and the thickness of the cell on the side where each receiving groove is located is H, where 2mm≤H≤15mm.

[0029] Secondly, the present invention also provides a battery pack comprising the aforementioned battery cells.

[0030] Beneficial effects: The battery pack with this structure has heat dissipation holes in the middle area of ​​the cells, which can improve the heat dissipation of the cells and the battery pack, and help improve the safety performance of the battery pack. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a top view of a battery cell according to an embodiment of the present invention;

[0033] Figure 2 for Figure 1 Sectional view along the middle AA direction;

[0034] Figure 3 This is a schematic diagram of the positive electrode, separator, and negative electrode in a battery cell according to an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of a battery cell in an embodiment of the present invention after the positive electrode, separator and negative electrode are stacked.

[0036] Figure 5 A schematic diagram showing the layout of the positive and negative electrode plates;

[0037] Figure 6 This is a schematic diagram of the first encapsulation film in a battery cell according to an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of an electrode sheet in a battery cell according to an embodiment of the present invention;

[0039] Figure 8 This is a top view of a battery cell according to an embodiment of the present invention;

[0040] Figure 9 This is a top view of another type of battery cell according to an embodiment of the present invention;

[0041] Figure 10 for Figure 9 BB-direction sectional view.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. First encapsulation film; 11. Receiving groove; 12. First through hole; 13. Inner edge extension; 14. Outer edge extension; 2. Second encapsulation film; 3. Positive electrode sheet; 31. Inner positive electrode tab; 4. Negative electrode sheet; 41. Inner negative electrode tab; 5. Separator; 6. Second through hole; 7. Outer positive electrode tab; 8. Outer negative electrode tab; 9. Tab adhesive. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] The battery cell in the relevant technology includes an internal tab and an external tab. The internal tab is connected to the electrode assembly, and the external tab is connected to the internal tab. One side of the external tab extends out of the encapsulation film, and the external tab occupies a certain space outside the encapsulation film. This results in a non-compact overall structure of the battery cell, which occupies a large space and is not conducive to the miniaturization of pouch batteries. It is difficult to meet the demand for small-volume batteries in mobile or wearable devices. Furthermore, the battery cell is a solid structure, which is not conducive to heat dissipation in the internal area of ​​the battery cell, resulting in poor overall heat dissipation performance.

[0046] The following is combined with Figures 1 to 10 The following describes embodiments of the present invention.

[0047] According to an embodiment of the present invention, in one aspect, a battery cell is provided, including an encapsulation film, an electrode assembly, an external positive electrode tab 7, and an external negative electrode tab 8.

[0048] The encapsulation film includes a first encapsulation film 1 and a second encapsulation film 2. At least one of the first encapsulation film 1 and the second encapsulation film 2 has a receiving groove 11. The first encapsulation film 1 and the second encapsulation film 2 inside the receiving groove 11 have a first through hole 12. The first encapsulation film 1 and the second encapsulation film 2 are sealed together. An electrode assembly is disposed in the receiving groove 11. The electrode assembly includes multiple electrode sheets and a separator 5. The electrode sheets include a positive electrode sheet 3 and a negative electrode sheet 4. A through second through hole 6 is provided in the middle region of the positive electrode sheet 3, the negative electrode sheet 4 and the separator 5. The positive electrode sheet 3 extends from the hole wall of its second through hole 6 to the inside of the second through hole 6. An internal positive electrode tab 31 is provided, and an internal negative electrode tab 41 extends from the wall of the second through hole 6 into the inner side of the second through hole 6. The internal positive electrode tab 31 and the internal negative electrode tab 41 are spaced apart. The second through hole 6 and the first through hole 12 are vertically connected. The external positive electrode tab 7 is welded to the internal positive electrode tab 31, and the external negative electrode tab 8 is welded to the internal negative electrode tab 41. The internal positive electrode tab 31 and the internal negative electrode tab 41 are located inside the first encapsulation film 1 and the second encapsulation film 2. One end of the external positive electrode tab 7 and the external negative electrode tab 8 is located inside the first through hole 12. The external positive electrode tab 7 and the external negative electrode tab 8 are spaced apart.

[0049] In this battery cell structure, a first through-hole 12 is provided on the inner side of the receiving groove 11 of the encapsulation film, and a second through-hole 6 is provided on the electrode and separator 5. After the battery cell is assembled, the first through-hole 12 and the second through-hole 6 are connected to form a vertically connected heat dissipation hole in the middle region of the battery cell. This can significantly improve the heat dissipation effect in the internal region of the battery cell, thereby effectively improving the overall heat dissipation effect of the battery cell and helping to improve the safety performance of the battery cell. At the same time, the internal electrode tab of the electrode extends towards the second through-hole 6, and the external electrode tab connects to the internal electrode tab and is located in the first through-hole 12 and the second through-hole 6 in the middle region of the battery cell. The external electrode tab does not occupy the space outside the outer contour of the encapsulation film, which can improve the compactness of the battery cell structure, reduce the space occupied by the battery cell, and make it suitable for the needs of small-volume batteries in mobile devices or wearable devices.

[0050] like Figure 1 , Figure 3 , Figures 7 to 9 As shown, in some embodiments, the first through hole 12 and the second through hole 6 are strip-shaped holes, with the internal positive electrode tab 31 and the internal negative electrode tab 41 arranged opposite each other on both sides of the length direction of the second through hole 6. After the electrode sheet is cut, the internal positive electrode tab 31 and the internal negative electrode tab 41 extend parallel to the electrode sheet toward the inside of the second through hole 6. After stacking, the internal positive electrode tab 31 is located on one side of the length direction of the second through hole 6, and the internal negative electrode tab 41 is located on the other side of the length direction of the second through hole 6. The structures of the positive electrode sheet 3 and the negative electrode sheet 4 can be the same, which facilitates the cutting and manufacturing of the positive electrode sheet 3 and the negative electrode sheet 4. After the positive electrode sheet 3 and the negative electrode sheet 4 are cut, the internal electrodes of the two are stacked with their internal electrodes arranged opposite each other, which can separate the internal positive electrode tab 31 and the internal negative electrode tab 41 along the length direction of the second through hole 6, preventing the internal positive electrode tab 31 and the internal negative electrode tab 41 from overlapping and short-circuiting. Meanwhile, the first through hole 12 and the second through hole 6 are strip-shaped holes, which helps to separate the external positive electrode 7 and the external negative electrode 8 along the length of the heat dissipation hole, reducing the risk of short circuit caused by contact between the external positive electrode 7 and the external negative electrode 8.

[0051] After stacking, all internal positive tabs 31 and all internal negative tabs 41 are soldered, with the soldered internal positive tabs 31 and internal negative tabs 41 positioned at one end of the electrode assembly thickness direction to facilitate soldering with the external tabs. This also allows the external tabs to be positioned between the first encapsulation film 1 and the second encapsulation film 2 for encapsulation. The external positive tabs 7 and external negative tabs 8 are arranged at intervals along the length direction of the first through-hole 12.

[0052] In other embodiments, the first through hole 12 and the second through hole 6 may also be square holes or round holes. The internal positive electrode 31 and the internal negative electrode 41 may be arranged opposite to or adjacent to each other. Correspondingly, the external positive electrode 7 and the external negative electrode 8 are also arranged opposite to or adjacent to each other. When electrodes with opposite polarities are arranged adjacent to each other, they need to be spaced at a sufficient distance to prevent short circuits.

[0053] Optionally, in some embodiments, the outer contour of the cross-section of the electrode assembly and electrode sheet is circular, and the shape of the receiving groove 11 is adapted to the shape of the electrode assembly, thereby forming a cylindrical cell with a central opening, so that it can be used in small portable electronic devices. The shape of the receiving groove 11 is adapted to the shape of the electrode assembly, that is, the receiving groove 11 is an annular groove.

[0054] In other embodiments, the outer contour of the cross-section of the electrode assembly and electrode sheet may also be rectangular, elliptical, rhomboid, etc.

[0055] In some embodiments, such as Figure 1 , Figure 3 , Figures 7 to 9 As shown, both the first through hole 12 and the second through hole 6 are rectangular in shape; Figure 7 As shown, the diameter of the electrode is D, and the width of the second through hole 6 is W. This configuration ensures the width of the second through hole 6, and the internal tabs are placed inside the second through hole 6, thus ensuring the width of the internal tabs and their current carrying capacity; at the same time, it prevents the size of the second through hole 6 from being too small, which would affect the heat dissipation of the inner area of ​​the cell. This design prevents the width of the second through hole 6 from being too large, which would result in the size of the electrode body being too small. It ensures the area of ​​the electrode body, thereby guaranteeing the strength and volumetric energy density of the battery cell.

[0056] In some embodiments, the diameter of the encapsulation film is d, that is, the outer diameter of the cell after encapsulation is d, and the width of the first through hole 12 is w. The width of the first through hole 12 is slightly smaller than the width of the second through hole 6. The first through hole 12 is located entirely inside the second through hole 6 in the circumferential direction, so that the first encapsulation film 1 and the second encapsulation film 2 encapsulate the hole wall of the second through hole 6 inside the encapsulation film. This design prevents the width of the first through hole 12 from being too small, which would limit the size of the external tab and thus affect the current carrying capacity of the external tab; at the same time, it avoids the first through hole 12 being too small, which would affect the heat dissipation of the battery cell. This design avoids making the width of the first through hole 12 too large, thus ensuring the volumetric energy density and overall strength of the battery cell.

[0057] In some embodiments, 40mm≤D≤100mm, 42mm≤d≤102mm.

[0058] The straight line containing one of the diameters of the electrode is called its centerline. In some embodiments, such as... Figure 7As shown, the second through hole 6 is symmetrically arranged along the center line of the electrode. The distance between the hole wall on one side of the length direction of the second through hole 6 and the center line of the electrode is L1, where 20mm≤L1≤60mm. L1≥20mm ensures that the second through hole 6 has sufficient length, preventing it from being too small and limiting the length of the internal electrode tabs; at the same time, L1≤60mm avoids the second through hole 6 being too long, preventing the electrode assembly from being affected by excessively long openings in terms of strength and volumetric energy density.

[0059] like Figure 8 As shown, in some embodiments, the first through-hole 12 is symmetrically arranged along the centerline of the encapsulation film. The distance between the edge of the sealing edge on one side of the length direction of the first through-hole 12 and the centerline of the encapsulation film is l1, 18mm≤11≤58mm. The length of the first through-hole 12 is slightly smaller than the length of the second through-hole 6, and the width of the first through-hole 12 is slightly smaller than the length of the second through-hole 6, so that the first through-hole 12 is located entirely inside the circumference of the second through-hole 6, so that the first encapsulation film 1 and the second encapsulation film 2 encapsulate the hole wall of the second through-hole 6 inside the encapsulation film. The 18mm≤11≤58mm arrangement avoids the first through-hole 12 being too small, thus limiting the size of the external tab and ensuring the current carrying capacity of the external tab; at the same time, it avoids the first through-hole 12 being too large, thus affecting the strength and volumetric energy density of the battery cell.

[0060] In some embodiments, such as Figure 7 As shown, before the internal tabs of all electrodes are soldered, the length of the internal tabs of the electrodes extending towards the center line of the electrode is L2. With L2 ≥ 10, this setting ensures the extension length of the internal tabs and guarantees their current-carrying capacity. Simultaneously... This can prevent the internal tabs from being too long and prevent the internal positive tab 31 and internal negative tab 41 from overlapping after the plates are stacked.

[0061] like Figures 3 to 5 and Figure 7 As shown, in some embodiments, the sidewall of the internal tab facing the long side of the second through hole 6 is spaced apart from the long side of the second through hole 6, so as to gather and weld the internal tabs of each layer in the thickness direction of the battery cell. After the internal tabs are welded, the gathered internal tabs are located at one end in the thickness direction of the electrode group. Then, a portion of the internal tabs is cut off along the length direction so that the ends of the internal tabs of each layer are flush. At this time, the overall length of the internal tabs is reduced compared to before they are gathered and welded. Then, an external tab is welded to one side of the internal tabs so that the first through hole 12 and the second through hole 6 have sufficient length space to accommodate the external tabs.

[0062] Optionally, such as Figure 7As shown, in some embodiments, the width of the side of the internal tab extending toward the center line of the electrode sheet is smaller than the width of the side connecting with the hole wall of the second through hole 6. This arrangement can ensure the connection strength between the internal tab and the electrode sheet body, while also making the two sides of the internal tab in the width direction spaced apart from the hole wall of the second through hole 6, so that the tabs of each layer can be bent and gathered in the direction of cell thickness.

[0063] For example, in some embodiments, the inner tab is trapezoidal, and the width of the inner tab gradually decreases from the wall of the second through hole 6 to the center line of the electrode sheet.

[0064] In other embodiments, the internal tabs may also be plate-shaped, triangular, or other shapes.

[0065] The first encapsulation film 1 and the second encapsulation film 2 are heat-sealed at the edges facing the first through hole 12 to form an inner edge sealing area, and the outer edges of the first encapsulation film 1 and the second encapsulation film 2 are heat-sealed at the outer edges to form an outer edge sealing area, so as to encapsulate the electrode assembly and the inner electrode tab inside the encapsulation film.

[0066] like Figure 8 As shown, in some embodiments, the distance between the edge of the sealing edge of the first through-hole 12 on the side where the inner tab is located and the end of the outer tab facing the center line of the encapsulation film is l2. l2≥8, this setting ensures the length of the external tabs and their current-carrying capacity. The external positive tab 7 and external negative tab 8 extend horizontally towards each other. This design prevents external tabs with opposite polarities from short-circuiting due to excessive length and overlapping.

[0067] like Figure 7 As shown, in some embodiments, before the internal tabs of all the electrodes are soldered, the internal tabs extend parallel to the electrode body toward the interior of the second through hole 6. The distance between the end of the internal tab facing the center line of the electrode and the center line of the electrode is L3, where L3 ≥ 2 mm. After the positive electrode 3 and the negative electrode 4 are stacked, the internal positive tab 31 and the internal negative tab 41 are positioned opposite each other on both sides of the center line of the electrode, with L3 satisfying L3 ≥ 2 mm. This arrangement further ensures that the internal positive tab 31 and the internal negative tab 41 are spaced apart after stacking, avoiding short circuits caused by contact between the positive and negative tabs.

[0068] Similarly, in some embodiments, such as Figure 8 As shown, the distance between the end of the external tab facing the center line of the encapsulation film and the center line of the encapsulation film is l3, where l3 ≥ 2 mm. This arrangement further ensures that the external positive tab 7 and the external negative tab 8 are separated, preventing short circuits caused by contact between the positive and negative tabs.

[0069] In some embodiments, such as Figure 2 and Figure 6 As shown, the end face of the inner wall of the receiving groove 11 is provided with an inner edge extension 13 extending toward the first through hole 12, and the end face of the outer wall of the receiving groove 11 is provided with an outer edge extension 14 extending outward. The outer electrode is provided on the inner edge extension 13. The first encapsulation film 1 and the second encapsulation film 2 are heat-sealed together, and the inner edge extension 13 and the outer edge extension 14 form a sealing area. By providing the inner edge extension 13 and the outer edge extension 14 on the groove wall of the receiving groove 11, it is convenient to heat-seal the first encapsulation film 1 and the second encapsulation film 2 together.

[0070] In this embodiment, the inner and outer walls of the receiving groove 11 extend vertically, while the inner edge, outer edge portion, and outer edge extension portion 14 extend horizontally.

[0071] like Figure 1 and Figure 2 As shown, in some embodiments, one of the first encapsulation film 1 and the second encapsulation film 2 is provided with a receiving groove 11, and the other of the first encapsulation film 1 and the second encapsulation film 2 is sealed at the end of the encapsulation film provided with the receiving groove 11; the thickness of the battery cell is H, 2mm≤H≤15mm. Since the encapsulation film has a certain degree of extensibility, if the stamping depth of the encapsulation film is too deep, i.e., the depth of the receiving groove 11 is too deep, the strength of the encapsulation film in the vicinity of the receiving groove 11 will be affected after stamping. To avoid this problem, the depth of the receiving groove 11 is controlled between 2mm and 15mm to ensure a suitable depth and effectively guarantee the strength of the encapsulation film.

[0072] like Figure 2 As shown, optionally, in some embodiments, the receiving groove 11 is disposed on the first encapsulation film 1, with the opening of the receiving groove 11 facing upwards, and the second encapsulation film 2 is encapsulated on the top of the first encapsulation film 1. The inner edge extension 13 and the outer edge extension 14 are disposed on the first encapsulation film 1.

[0073] In other embodiments, such as Figure 9 and Figure 10 As shown, both the first encapsulation film 1 and the second encapsulation film 2 are provided with receiving grooves 11, and the thickness of the battery cell on the side where each receiving groove 11 is located is H, where 2mm≤H≤15mm. In this embodiment, the first encapsulation film 1 and the second encapsulation film 2 are each provided with an inner edge extension 13 and an outer edge extension 14 at their opposite ends. The inner edge extensions 13 of the two are heat-sealed together, and the outer edge extensions 14 of the two are sealed together.

[0074] The battery cell also includes tab adhesive 9, one side of which is connected to an external tab, and the other side of which is sealed to the encapsulation film during the heat-sealing process.

[0075] According to an embodiment of the present invention, another aspect provides a battery pack including the aforementioned battery cells.

[0076] This battery pack has heat dissipation holes in the middle area of ​​the cells, which can improve the heat dissipation of the cells and the battery pack, and help improve the safety performance of the battery pack.

[0077] Although embodiments of the 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 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: The encapsulation film includes a first encapsulation film and a second encapsulation film. At least one of the first encapsulation film and the second encapsulation film is provided with a receiving groove. The first encapsulation film and the second encapsulation film are provided with a first through hole inside the receiving groove. The first encapsulation film and the second encapsulation film are sealed together. An electrode assembly is disposed within the receiving groove; the electrode assembly includes multiple electrode plates and a separator, the electrode plates including positive electrode plates and negative electrode plates; a through second hole is provided in the middle region of the positive electrode plate, the negative electrode plate and the separator; an internal positive electrode tab extends from the wall of the second through hole into the inside of the second through hole of the positive electrode plate, and an internal negative electrode tab extends from the wall of the second through hole into the inside of the second through hole of the negative electrode plate, the internal positive electrode tab and the internal negative electrode tab being spaced apart; the second through hole and the first through hole are vertically connected; An external positive electrode and an external negative electrode are provided. The external positive electrode is welded to the internal positive electrode, and the external negative electrode is welded to the internal negative electrode. The internal positive electrode and the internal negative electrode are located inside the first encapsulation film and the second encapsulation film. One end of the external positive electrode and the external negative electrode is located inside the first through hole and the second through hole. The external positive electrode and the external negative electrode are spaced apart. The outer contour of the cross-section of the electrode assembly and the electrode sheet is circular, and the shape of the receiving groove is adapted to the shape of the electrode assembly; Both the first and second through holes are rectangular; the diameter of the electrode is D, the width of the second through hole is W, the diameter of the encapsulation film is d, and the width of the first through hole is w. ; And / or, .

2. The battery cell according to claim 1, characterized in that, The first through hole and the second through hole are strip-shaped holes, and the internal positive electrode tab and the internal negative electrode tab are disposed on opposite sides of the length direction of the first through hole.

3. The battery cell according to claim 1, characterized in that, The second through hole is symmetrically arranged along the center line of the electrode, and the distance between the hole wall on one side of the length direction of the second through hole and the center line of the electrode is L1, 20mm≤L1≤60mm; And / or, the first through hole is symmetrically arranged along the center line of the encapsulation film, and the distance between the edge of the sealing edge on one side of the length direction of the first through hole and the center line of the encapsulation film is l1, 18mm≤11≤58mm.

4. The battery cell according to claim 1, characterized in that, Before the internal tabs of all the electrodes are soldered, the length of the internal tabs of the electrodes extending toward the centerline of the electrodes is L2. ; And / or, the distance between the edge of the sealing edge of the first through hole on the side where the inner tab is located and the end of the outer tab facing the center line of the encapsulation film is l2. .

5. The battery cell according to claim 1, characterized in that, Before the internal tabs of all the electrodes are welded, the distance between the end of the internal tab of the electrode facing the center line of the electrode and the center line of the electrode is L3, where L3 ≥ 2 mm; And / or, the distance between the end of the external tab facing the center line of the encapsulation film and the center line of the encapsulation film is l3, where l3 ≥ 2 mm.

6. The battery cell according to claim 1 or 2, characterized in that, The end face of the inner wall of the receiving groove is provided with an inner edge extension extending toward the first through hole, and the end face of the outer wall of the receiving groove is provided with an outer edge extension extending outward. An external electrode is provided on the inner edge extension. The first encapsulation film and the second encapsulation film are heat-sealed together, and the inner edge extension and the outer edge extension form a sealing area.

7. The battery cell according to claim 1 or 2, characterized in that, The first encapsulation film and the second encapsulation film are provided with the receiving groove, and the other encapsulation film is sealed at the end of the encapsulation film provided with the receiving groove; the thickness of the battery cell is H, 2mm≤H≤15mm; Alternatively, both the first encapsulation film and the second encapsulation film are provided with the receiving groove, and the thickness of the cell on the side where each receiving groove is located is H, where 2mm≤H≤15mm.

8. A battery pack, characterized in that, Includes the battery cell according to any one of claims 1 to 7.

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