Battery cell and battery pack

Abstract

The invention relates to the technical field of battery cells, and discloses a battery cell and a battery pack, and the battery cell comprises a packaging film, a pole group, an external positive tab and an external negative tab. A first through hole is formed in the inner side of the containing groove of the packaging film, a second through hole is formed in the pole piece and the diaphragm, and after the battery cell is assembled, the first through hole and the second through hole are communicated to form a vertically-through heat dissipation hole in the middle area of the battery cell, so that the heat dissipation effect of the internal area of the battery cell can be remarkably improved, the overall heat dissipation effect of the battery cell can be effectively improved, and the service life of the battery cell is prolonged. And the safety performance of the battery cell is improved. Meanwhile, the internal tabs of the pole pieces extend towards the second through holes, the external tabs are connected with the internal tabs and located in the first through holes and the second through holes in the middle area of the battery cell, and the external tabs do not occupy the space outside the outer contour of the packaging film, so that the compactness of the battery cell structure can be improved, and the occupied space of the battery cell is reduced; therefore, the battery can meet the requirement of a mobile device or a wearable device for a small-size battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery cells, and in particular to a battery cell and a battery pack. Background Art

[0002] Soft-pack batteries generally have single-sided or double-sided tabs, and the tabs are all arranged on the periphery of the soft-pack batteries, resulting in a large overall space occupied by the soft-pack batteries, which is not conducive to the miniaturization of soft-pack batteries and is difficult to adapt to the demand for small-volume batteries in mobile devices or wearable devices; and the existing soft-pack batteries have poor heat dissipation effects. Summary of the invention

[0003] In view of this, the present invention provides a battery cell and a battery pack to solve the problem that the soft-pack battery in the prior art occupies a large space and has a poor heat dissipation effect due to the external placement of the tabs.

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

[0005] The packaging film comprises a first packaging film and a second packaging film, wherein at least one of the first packaging film and the second packaging film is provided with a containing groove, and the first packaging film and the second packaging film inside the containing groove are provided with a first through hole; the first packaging film and the second packaging film are butt-jointed and edge-sealed;

[0006] An electrode group is arranged in the accommodating groove; the electrode group includes a plurality of electrode sheets and a diaphragm, the electrode sheets include a positive electrode sheet and a negative electrode sheet; a second through hole is provided in the middle area of ​​the positive electrode sheet, the negative electrode sheet and the diaphragm; the positive electrode sheet extends an internal positive electrode ear from the hole wall of the second through hole to the inner side of the second through hole, and the negative electrode sheet extends an internal negative electrode ear from the hole wall of the second through hole to the inner side of the second through hole, and the internal positive electrode ear is arranged at intervals from the internal negative electrode ear; the second through hole is vertically connected with the first through hole;

[0007] An external positive ear and an external negative ear, the external positive ear is welded to the internal positive ear, the external negative ear is welded to the internal negative ear, the internal positive ear and the internal negative ear are located in the first packaging film and the second packaging film, one end of the external positive ear and the external negative ear are located in the first through hole and the second through hole; the external positive ear and the external negative ear are spaced apart.

[0008] Beneficial effects: In the battery cell of this structure, a first through hole is provided on the inner side of the receiving groove of the packaging film, and a second through hole is provided on the pole piece and the diaphragm. After the battery cell is assembled, the first through hole and the second through hole are connected to form a heat dissipation hole that passes through from top to bottom in the middle area of ​​the battery cell, which can significantly improve the heat dissipation effect of the internal area of ​​the battery cell, thereby effectively improving the heat dissipation effect of the battery cell as a whole, which is beneficial to improving the safety performance of the battery cell. At the same time, the internal pole ear of the pole piece extends toward the second through hole, and the external pole ear connects the internal pole ear and is located in the first through hole and the second through hole in the middle area of ​​the battery cell. The external pole ear does not occupy the space outside the outer contour of the packaging film, which can improve the compactness of the battery cell structure and reduce the space occupied by the battery cell, so that it can be used for the demand for small-volume batteries in mobile devices or wearable devices.

[0009] In an optional embodiment, the first through hole and the second through hole are in the shape of strip holes, and the internal positive electrode tab and the internal negative electrode tab are arranged oppositely on both sides of the second through hole in the length direction.

[0010] Beneficial effect: After the electrode sheet is cut, the internal positive electrode ear and the internal negative electrode ear extend parallel to the electrode sheet toward the inner side of the second through hole. After lamination, the internal positive electrode ear is located on one side of the length direction of the second through hole, and the internal negative electrode ear is located on the other side of the length direction of the second through hole. The structures of the positive electrode sheet and the negative electrode sheet can be the same, which is convenient for cutting and making positive electrode sheets and negative electrode sheets. After the positive electrode sheet and the negative electrode sheet are cut, the internal electrode ears of the two are arranged oppositely and stacked, so that the internal positive electrode ear and the internal negative electrode ear can be separated along the length direction of the second through hole to prevent the internal positive electrode ear and the internal negative electrode ear from overlapping and short-circuiting each other. At the same time, the first through hole and the second through hole are in the shape of strip holes, which is conducive to separating the external positive electrode ear and the external negative electrode ear along the length direction of the heat dissipation hole, reducing the risk of short circuit caused by contact between the external positive electrode ear and the external negative electrode ear.

[0011] In an optional embodiment, the outer contours of the cross sections of the pole group and the pole piece are circular, and the shape of the accommodating groove is adapted to the shape of the pole group.

[0012] In an optional embodiment, the first through hole and the second through hole are both rectangular holes; the diameter of the pole piece is D, the width of the second through hole is W, the diameter of the packaging film is d, and the width of the first through hole is w.

[0013] and / or,

[0014] Beneficial effect: This arrangement can ensure the width of the second through hole. The internal pole ear is arranged in the second through hole, so as to ensure the width size of the internal pole ear and the current carrying capacity of the internal pole ear; at the same time, it can prevent the size of the second through hole from being too small to affect the heat dissipation of the inner area of ​​the battery cell. Such an arrangement can prevent the width of the second through hole from being too large, which would result in the size of the pole piece entity being too small, and can ensure the area of ​​the pole piece entity part, thereby ensuring the strength and volume energy density of the battery cell.

[0015] The width of the first through hole is slightly smaller than that of the second through hole. The first through hole is entirely located inside the circumference of the second through hole, so that the first packaging film and the second packaging film package the hole wall of the second through hole inside the packaging film. This arrangement can prevent the width of the first through hole from being too small and limiting the size of the external pole ear, thereby affecting the current capacity of the external pole ear; and at the same time, it can prevent the size of the first through hole from being too small and affecting the heat dissipation of the battery cell; Such an arrangement can prevent the width of the first through hole from being too large, thereby ensuring the volume energy density of the battery cell and the overall strength of the battery cell.

[0016] In an optional embodiment, the second through hole is symmetrically arranged along the center line of the pole piece, 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 pole piece is L1, 20mm≤L1≤60mm;

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

[0018] Beneficial effects: L1≥20mm, such a setting can ensure that the second through hole has sufficient length, preventing the length of the second through hole from being too short and limiting the length of the internal pole ear; at the same time, L1≤60mm, such a setting can avoid the length of the second through hole from being too long, avoiding the pole group from affecting its strength and volume energy density due to the excessive length of the opening.

[0019] 18mm≤11≤58mm. This arrangement can avoid the length of the first through hole being too small and limiting the size of the external pole ear, which is beneficial to ensuring the current carrying capacity of the external pole ear; at the same time, it can avoid the size of the first through hole being too large and affecting the strength and volume energy density of the battery cell.

[0020] In an optional embodiment, before the internal tabs of all the pole pieces are welded, the length of the internal tabs of the pole piece extending toward one side of the center line of the pole piece is L2,

[0021] and / or, the distance between the edge of the sealing edge of the first through hole on the side where the internal tab is located and one end of the external tab facing the center line of the packaging film is l2,

[0022] Beneficial effect: L2≥10, this setting can ensure the extension length of the internal tab and the current capacity of the internal tab. This can prevent the length of the internal pole ear from being too long, and prevent the internal positive pole ear and the internal negative pole ear that are relatively arranged after lamination from overlapping.

[0023] l2≥8, this setting can ensure the length of the external pole ear and the current capacity of the external pole ear. The external positive pole ear and the external negative pole ear extend horizontally towards each other. This arrangement can prevent external pole ears with opposite polarities from overlapping and short-circuiting each other due to excessive length.

[0024] In an optional embodiment, before the internal pole lugs of all the pole pieces are welded, the distance between one end of the internal pole lug of the pole piece facing the center line of the pole piece and the center line of the pole piece is L3, and L3 ≥ 2 mm;

[0025] And / or, the distance between one end of the external electrode ear facing the center line of the packaging film and the center line of the packaging film is l3, and l3≥2mm.

[0026] In an optional embodiment, the end surface of the inner groove wall of the accommodating groove is provided with an inner edge extension portion extending toward the first through hole, the end surface of the outer groove wall of the accommodating groove is provided with an outer edge extension portion extending outward, and the external pole ear is arranged on the inner edge extension portion; the first packaging film and the second packaging film are butt-heat-sealed, and the inner edge extension portion and the outer edge extension portion form a sealing edge area.

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

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

[0029] In a second aspect, the present invention also provides a battery pack, comprising the above-mentioned battery cell.

[0030] Beneficial effects: The battery pack of this structure has heat dissipation holes in the middle area of ​​the battery cells therein, which can improve the heat dissipation effect of the battery cells and the battery pack, and is beneficial to improving the safety performance of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

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

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

[0035] Figure 4 This is a schematic diagram of a positive electrode sheet, a separator and a negative electrode sheet after being stacked in a battery cell according to an embodiment of the present invention;

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

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

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

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

[0040] Fig. 9 A top view of another battery cell according to an embodiment of the present invention;

[0041] Fig.10 for Fig. 9 BB section view.

[0042] Description of reference numerals:

[0043] 1. First packaging film; 11. Accommodating groove; 12. First through hole; 13. Inner edge extension; 14. Outer edge extension; 2. Second packaging film; 3. Positive electrode sheet; 31. Internal positive electrode ear; 4. Negative electrode sheet; 41. Internal negative electrode ear; 5. Diaphragm; 6. Second through hole; 7. External positive electrode ear; 8. External negative electrode ear; 9. Ear glue. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0045] The battery cell in the related technology includes an internal pole ear and an external pole ear, the internal pole ear is connected to the pole group, the external pole ear is connected to the internal pole ear, and one side of the external pole ear extends out of the packaging film, and the external pole ear occupies a certain space outside the packaging film, resulting in the overall structure of the battery cell being not compact and occupying a large space, which is not conducive to the miniaturization of soft-pack batteries and is difficult to meet the demand for small-volume batteries in mobile devices or wearable devices; and the battery cell as a whole is a solid structure, which is not conducive to the heat dissipation of the internal area of ​​the battery cell, resulting in poor heat dissipation effect of the battery cell as a whole.

[0046] Combine the following Figures 1 to 10 , describing an embodiment of the present invention.

[0047] According to an embodiment of the present invention, on the one hand, a battery cell is provided, including a packaging film, an electrode group, an external positive electrode tab 7 and an external negative electrode tab 8.

[0048] The packaging film includes a first packaging film 1 and a second packaging film 2, at least one of which is provided with a receiving groove 11, and the first packaging film 1 and the second packaging film 2 inside the receiving groove 11 are provided with a first through hole 12; the first packaging film 1 and the second packaging film 2 are butt-sealed; the electrode group is arranged in the receiving groove 11; the electrode group includes a plurality of electrode sheets and a diaphragm 5, and 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 area of ​​the positive electrode sheet 3, the negative electrode sheet 4 and the diaphragm 5; the positive electrode sheet 3 extends from the hole wall of the second through hole 6 to the inner side of the second through hole 6 The internal positive ear 31 is extended, and the internal negative ear 41 of the negative electrode sheet 4 extends from the hole wall of the second through hole 6 to the inner side of the second through hole 6, and the internal positive ear 31 and the internal negative ear 41 are arranged at intervals; the second through hole 6 and the first through hole 12 are connected vertically; the external positive ear 7 is welded to the internal positive ear 31, and the external negative ear 8 is welded to the internal negative ear 41, the internal positive ear 31 and the internal negative ear 41 are located in the first packaging film 1 and the second packaging film 2, and one end of the external positive ear 7 and the external negative ear 8 are located in the first through hole 12; the external positive ear 7 and the external negative ear 8 are arranged at intervals.

[0049] In the battery cell of this structure, the inner side of the receiving groove 11 of the packaging film is provided with a first through hole 12, and the pole piece and the diaphragm 5 are provided with a second through hole 6. After the battery cell is assembled, the first through hole 12 and the second through hole 6 are connected to form a heat dissipation hole that passes through from top to bottom in the middle area of ​​the battery cell, which can significantly improve the heat dissipation effect of the internal area of ​​the battery cell, thereby effectively improving the heat dissipation effect of the battery cell as a whole, which is conducive to improving the safety performance of the battery cell. At the same time, the internal pole ear of the pole piece extends toward the second through hole 6, and the external pole ear connects the internal pole ear and is located in the first through hole 12 and the second through hole 6 in the middle area of ​​the battery cell. The external pole ear does not occupy the space outside the outer contour of the packaging film, which can improve the compactness of the battery cell structure and reduce the space occupied by the battery cell, so that it can be used for the demand for 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 in the shape of strip holes, and the internal positive electrode ear 31 and the internal negative electrode ear 41 are arranged on both sides of the length direction of the second through hole 6. After the electrode sheet is cut, the internal positive electrode ear 31 and the internal negative electrode ear 41 extend toward the inner side of the second through hole 6 in parallel with the electrode sheet. After lamination, the internal positive electrode ear 31 is located on one side of the length direction of the second through hole 6, and the internal negative electrode ear 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 is convenient for cutting and making 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 electrode ears of the two are arranged oppositely and stacked, so that the internal positive electrode ear 31 and the internal negative electrode ear 41 can be separated along the length direction of the second through hole 6 to prevent the internal positive electrode ear 31 and the internal negative electrode ear 41 from overlapping and short-circuiting each other. At the same time, the first through hole 12 and the second through hole 6 are in the shape of strip holes, which is conducive to separating the external positive electrode ear 7 and the external negative electrode ear 8 along the length direction of the heat dissipation hole, thereby reducing the risk of short circuit caused by contact between the external positive electrode ear 7 and the external negative electrode ear 8.

[0051] After lamination, all the internal positive tabs 31 and all the internal negative tabs 41 are welded, and the welded internal positive tabs 31 and internal negative tabs 41 are located at one end of the electrode group thickness direction so that they can be welded with the external tabs, and at the same time, the external tabs are conveniently located between the first packaging film 1 and the second packaging film 2 so as to package the external tabs. The external positive tabs 7 and the 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 ear 31 and the internal negative electrode ear 41 may be arranged opposite to or adjacent to each other, and correspondingly, the external positive electrode ear 7 and the external negative electrode ear 8 are also arranged opposite to or adjacent to each other. When the electrodes with opposite polarities are arranged adjacent to each other, they need to be spaced apart by a sufficient distance to prevent contact short circuit.

[0053] Optionally, in some embodiments, the outer contour of the cross section of the electrode group and the electrode piece is circular, and the shape of the receiving groove 11 is adapted to the shape of the electrode group, thereby forming a cylindrical battery cell with a hole in the middle, so that it can be suitable for small portable electronic devices. The shape of the receiving groove 11 is adapted to the shape of the electrode group, that is, the receiving groove 11 is in the shape of a circular ring groove.

[0054] In other embodiments, the outer contour of the cross section of the pole group and the pole piece may also be in the shape of a rectangle, an ellipse, a diamond, etc.

[0055] In some embodiments, Figure 1 , Figure 3 , Figures 7 to 9 As shown, the first through hole 12 and the second through hole 6 are both rectangular holes; Figure 7 As shown, the diameter of the pole piece is D, the width of the second through hole 6 is W, This arrangement can ensure the width of the second through hole 6. The internal pole ear is arranged in the second through hole 6, so as to ensure the width size of the internal pole ear and the current carrying capacity of the internal pole ear; at the same time, it can prevent the size of the second through hole 6 from being too small to affect the heat dissipation of the inner area of ​​the battery cell. Such an arrangement can prevent the width of the second through hole 6 from being too large, which would result in the size of the pole piece entity being too small, and can ensure the area of ​​the pole piece entity part, thereby ensuring the strength and volume energy density of the battery cell.

[0056] In some embodiments, the diameter of the packaging film is d, that is, the outer diameter of the battery cell after packaging by the packaging film 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 that of the second through hole 6 , and the first through hole 12 is entirely located on the inner side of the second through hole 6 in the circumferential direction, so that the first packaging film 1 and the second packaging film 2 package the hole wall of the second through hole 6 on the inner side of the packaging film. This arrangement can prevent the width of the first through hole 12 from being too small and limiting the size of the external pole ear, thereby affecting the current capacity of the external pole ear; at the same time, it can prevent the size of the first through hole 12 from being too small and affecting the heat dissipation of the battery cell; Such an arrangement can prevent the width of the first through hole 12 from being too large, thereby ensuring the volume energy density of the battery cell and the overall strength of the battery cell.

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

[0058] The straight line on which a diameter of a pole piece lies is called its center line. In some embodiments, such as Figure 7As shown, the second through hole 6 is symmetrically arranged along the center line of the pole piece, and 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 pole piece is L1, 20mm≤L1≤60mm. L1≥20mm, such an arrangement can ensure that the second through hole 6 has a sufficient length, and prevent the length of the second through hole 6 from being too small to limit the length of the internal pole ear; at the same time, L1≤60mm, such an arrangement can avoid the length of the second through hole 6 being too long, and avoid the pole group from affecting its strength and volume energy density due to the excessive length of the opening.

[0059] like Figure 8 As shown, in some embodiments, the first through hole 12 is symmetrically arranged along the center line of the packaging film, and the distance between the edge of the sealing edge on one side of the length direction of the first through hole 12 and the center line of the packaging 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 on the inner side of the circumference of the second through hole 6 as a whole, so that the first packaging film 1 and the second packaging film 2 encapsulate the hole wall of the second through hole 6 on the inner side of the packaging film. 18mm≤11≤58mm, such a setting can avoid the length of the first through hole 12 being too small to limit the size of the external pole ear, which is conducive to ensuring the current capacity of the external pole ear; at the same time, it can avoid the size of the first through hole 12 being too large to affect the strength and volume energy density of the battery cell.

[0060] In some embodiments, Figure 7 As shown, before the internal pole ears of all pole pieces are welded, the length of the internal pole ears of the pole pieces extending toward one side of the center line of the pole pieces is L2. L2≥10, this setting can ensure the extension length of the internal tab and the current capacity of the internal tab. This can prevent the length of the internal pole ear from being too long, and prevent the internal positive pole ear 31 and the internal negative pole ear 41 that are arranged opposite to each other after lamination from overlapping.

[0061] like Figures 3 to 5 and Figure 7 As shown, in some embodiments, the side wall of the internal pole ear facing the long side hole wall of the second through hole 6 is spaced from the long side hole wall of the second through hole 6 so as to gather and weld each layer of internal pole ears in the thickness direction of the battery cell. After the internal pole ears are welded, the gathered internal pole ears are located at one end in the thickness direction of the pole group, and then a part of the internal pole ears are cut off in the length direction so that the ends of the internal pole ears of each layer are flush. At this time, the overall length of the internal pole ears is reduced compared to before the gathering and welding, and then the external pole ears are welded on one side of the internal pole ears so that the first through hole 12 and the second through hole 6 have enough length space to accommodate the external pole ears.

[0062] Alternatively, if Figure 7As shown, in some embodiments, the width of the side of the internal pole ear extending toward the center line of the pole piece is smaller than the width of the side connected to the hole wall of the second through hole 6. This arrangement can ensure the connection strength between the internal pole ear and the pole piece body, while separating the two side edges of the internal pole ear in the width direction from the hole wall of the second through hole 6, so that each layer of pole ears can bend and gather toward the thickness direction of the battery cell.

[0063] For example, in some embodiments, the internal pole ear is trapezoidal, and the width of the internal pole ear gradually decreases from the hole wall of the second through hole 6 to one side of the center line of the pole piece.

[0064] In other embodiments, the internal tab may also be in the shape of an oval plate, a triangle, or the like.

[0065] The first packaging film 1 and the second packaging film 2 are heat-pressed and sealed at the edges facing the first through hole 12 to form an inner edge sealing area, and the outer edges facing outward of the first packaging film 1 and the second packaging film 2 are heat-pressed and sealed to form an outer edge sealing area to encapsulate the electrode group and the internal electrode ears in the packaging film.

[0066] like Figure 8 As shown, in some embodiments, the distance between the edge of the sealed edge of the first through hole 12 on the side where the internal tab is located and one end of the external tab facing the center line of the packaging film is l2, l2≥8, such a setting can ensure the length of the external pole ear and the current capacity of the external pole ear. The external positive pole ear 7 and the external negative pole ear 8 extend horizontally toward each other. This arrangement can prevent external pole ears with opposite polarities from overlapping and short-circuiting each other due to excessive length.

[0067] like Figure 7 As shown, in some embodiments, before the internal pole ears of all pole sheets are welded, the internal pole ears extend toward the inside of the second through hole 6 in parallel with the pole sheet body, and the distance between one end of the internal pole ear of the pole sheet facing the center line of the pole sheet and the center line of the pole sheet is L3, and L3≥2mm. After the positive pole sheet 3 and the negative pole sheet 4 are stacked, the internal positive pole ear 31 and the internal negative pole ear 41 are arranged on both sides of the center line of the pole sheet, and L3 satisfies L3≥2mm. Such a setting can further ensure that the internal positive pole ear 31 and the internal negative pole ear 41 are spaced apart after stacking, so as to avoid short circuit between the positive and negative pole ears.

[0068] Similarly, in some embodiments, if Figure 8 As shown, the distance between the end of the external pole ear facing the center line of the packaging film and the center line of the packaging film is l3, l3 ≥ 2mm. This arrangement can further ensure that the external positive pole ear 7 is spaced from the external negative pole ear 8 to avoid short circuit between the positive and negative pole ears.

[0069] In some embodiments, Figure 2 and Figure 6 As shown, the end surface of the inner groove wall of the containing groove 11 is provided with an inner edge extension portion 13 extending toward the first through hole 12, the end surface of the outer groove wall of the containing groove 11 is provided with an outer edge extension portion 14 extending outward, and the external pole ear is provided on the inner edge extension portion 13; the first packaging film 1 and the second packaging film 2 are butt-jointed and heat-sealed, and the inner edge extension portion 13 and the outer edge extension portion 14 form a sealing edge area. By providing the inner edge extension portion 13 and the outer edge extension portion 14 on the groove wall of the containing groove 11, it is convenient for the first packaging film 1 and the second packaging film 2 to be butt-jointed and heat-sealed.

[0070] In this embodiment, the inner groove wall and the outer groove wall of the accommodating groove 11 extend vertically, and the inner edge outer edge portion and the outer edge extension portion 14 all extend horizontally.

[0071] like Figure 1 and Figure 2 As shown, in some embodiments, one of the first packaging film 1 and the second packaging film 2 is provided with a receiving groove 11, and the other of the first packaging film 1 and the second packaging film 2 is sealed at the end of the packaging film provided with the receiving groove 11; the thickness of the battery cell is H, 2mm≤H≤15mm. Since the packaging film has a certain ductility, if the stamping depth of the packaging film is too deep, that is, the depth of the receiving groove 11 is deep, the strength of the packaging film in the area near the receiving groove 11 will be affected after the packaging film is stamped. In order to avoid this problem, the depth of the receiving groove 11 is controlled between 2mm and 15mm, so that the depth of the receiving groove 11 is moderate, thereby effectively ensuring the strength of the packaging film.

[0072] like Figure 2 As shown, optionally, in some embodiments, the receiving groove 11 is disposed on the first packaging film 1, the notch of the receiving groove 11 faces upward, and the second packaging film 2 is packaged on the top of the first packaging film 1. The inner edge extension portion 13 and the outer edge extension portion 14 are disposed on the first packaging film 1.

[0073] In other embodiments, Fig. 9 and Fig.10 As shown, the first packaging film 1 and the second packaging film 2 are both provided with a receiving groove 11, and the thickness of the battery cell on the side where each receiving groove 11 is located is H, 2mm≤H≤15mm. In this embodiment, the first packaging film 1 and the second packaging film 2 are both provided with an inner edge extension portion 13 and an outer edge extension portion 14 at the ends facing each other, and the inner edge extension portions 13 of the two are butt-jointed and heat-sealed, and the outer edge extension portions 14 of the two are butt-jointed and sealed.

[0074] The battery cell further comprises a tab glue 9, one side of which is connected to an external tab, and the other side of which is sealed and connected to the packaging film when the packaging film is hot-pressed and sealed.

[0075] According to an embodiment of the present invention, on the other hand, a battery pack is provided, comprising the above-mentioned battery cell.

[0076] In a battery pack of this structure, a heat dissipation hole is provided in the middle area of ​​the battery cell therein, which can improve the heat dissipation effect of the battery cell and the battery pack and is beneficial to improving the safety performance of the battery pack.

[0077] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that: include: The packaging film comprises a first packaging film and a second packaging film, wherein at least one of the first packaging film and the second packaging film is provided with a containing groove, and the first packaging film and the second packaging film inside the containing groove are provided with a first through hole; the first packaging film and the second packaging film are butt-jointed and edge-sealed; An electrode group is arranged in the accommodating groove; the electrode group includes a plurality of electrode sheets and a diaphragm, the electrode sheets include a positive electrode sheet and a negative electrode sheet; a second through hole is provided in the middle area of ​​the positive electrode sheet, the negative electrode sheet and the diaphragm; the positive electrode sheet extends an internal positive electrode ear from the hole wall of the second through hole to the inner side of the second through hole, and the negative electrode sheet extends an internal negative electrode ear from the hole wall of the second through hole to the inner side of the second through hole, and the internal positive electrode ear is arranged at intervals from the internal negative electrode ear; the second through hole is vertically connected with the first through hole; An external positive ear and an external negative ear, the external positive ear is welded to the internal positive ear, the external negative ear is welded to the internal negative ear, the internal positive ear and the internal negative ear are located in the first packaging film and the second packaging film, one end of the external positive ear and the external negative ear are located in the first through hole and the second through hole; the external positive ear and the external negative ear are spaced apart.

2. The battery cell according to claim 1, characterized in that: The first through hole and the second through hole are in the shape of strip holes, and the internal positive electrode tab and the internal negative electrode tab are arranged oppositely on both sides of the first through hole in the length direction.

3. The battery cell according to claim 1 or 2, characterized in that: The outer contours of the cross sections of the pole group and the pole piece are circular, and the shape of the accommodating groove is adapted to the shape of the pole group.

4. The battery cell according to claim 3, characterized in that: The first through hole and the second through hole are both rectangular holes; the diameter of the pole piece is D, the width of the second through hole is W, the diameter of the packaging film is d, and the width of the first through hole is w. and / or, 5. The battery cell according to claim 4, characterized in that: The second through hole is symmetrically arranged along the center line of the pole piece, 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 pole piece is L1, 20mm≤L1≤60mm; And / or, the first through holes are symmetrically arranged along the center line of the packaging film, and the distance between the edge of the sealed edge on one side of the length direction of the first through holes and the center line of the packaging film is l1, 18mm≤11≤58mm.

6. The battery cell according to claim 4, characterized in that: Before the internal tabs of all the pole pieces are welded, the length of the internal tabs of the pole piece extending toward one side of the center line of the pole piece is L2. and / or, the distance between the edge of the sealing edge of the first through hole on the side where the internal tab is located and one end of the external tab facing the center line of the packaging film is l2, 7. The battery cell according to claim 4, characterized in that: Before the internal pole lugs of all the pole pieces are welded, the distance between one end of the internal pole lug of the pole piece facing the center line of the pole piece and the center line of the pole piece is L3, and L3 is ≥ 2 mm; And / or, the distance between one end of the external electrode ear facing the center line of the packaging film and the center line of the packaging film is l3, and l3≥2mm.

8. The battery cell according to claim 1 or 2, characterized in that: The end surface of the inner groove wall of the accommodating groove is provided with an inner edge extension portion extending toward the first through hole, and the end surface of the outer groove wall of the accommodating groove is provided with an outer edge extension portion extending outward, and the external pole ear is arranged on the inner edge extension portion; the first packaging film and the second packaging film are butt-heat-sealed, and the inner edge extension portion and the outer edge extension portion form a sealing edge area.

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

10. A battery pack, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 9.

Images