Battery cell and battery

Abstract

The utility model provides a battery cell and a battery. The battery cell comprises a first pole piece and a second pole piece which are wound across a diaphragm. The first pole piece comprises a first current collector. The first current collector is provided with a first surface and a second surface which are opposite in the first direction, and the first surface is provided with a first empty foil area and a first layout area. A first active layer is arranged in the first arrangement area, and a first safety layer is arranged in the first empty foil area. The first safety layer is provided with a first tab groove exposing a first part of the first surface, and the first tab is connected with the first part. The first pole piece is provided with a first notch, and the first tab groove and the first notch are oppositely arranged along a second direction orthogonal to the first direction; and / or, the first pole piece is provided with a second gap, and the second gap is located at the edge of the first tab groove. According to the battery cell and the battery provided by the embodiment of the utility model, due to the existence of the first gap and / or the second gap, the safety risk is reduced.

Description

Technical Field

[0001] The embodiments of the utility model relate to the field of batteries, and in particular, to a battery cell and a battery. Background Art

[0002] A battery is a device that supplies electrical energy to electrical equipment. A battery may include a battery cell, which may include a pair of pole pieces wound with a separator, namely a positive pole piece and a negative pole piece. A pole piece may include a current collector and an active layer disposed thereon. To lead out the current, the pole piece may also include a pole ear connected to the current collector. If the structure of the pole ear-related parts is not reasonable, the safety risk will increase. Utility Model Content

[0003] In view of this, an embodiment of the utility model provides a battery cell and a battery to reduce safety risks.

[0004] On the one hand, an embodiment of the utility model provides a battery cell. The battery cell includes a first pole piece and a second pole piece wound with a diaphragm. The first pole piece includes a first current collector, and the first current collector has a first surface and a second surface opposite to each other along a first direction. The first surface has a first empty foil area and a first layout area, the first layout area is provided with a first active layer, and the first empty foil area is provided with a first safety layer. The first safety layer is provided with a first pole ear groove exposing a first portion of the first surface, and the first pole ear is connected to the first portion. The first pole piece is provided with a first notch, and the first pole ear groove and the first notch are arranged opposite to each other along the second direction; and / or, the first pole piece is provided with a second notch, and the second notch is located at the edge of the first pole ear groove. The first direction and the second direction are orthogonal.

[0005] In a possible implementation, the first pole piece satisfies: 4.5mm≤W1≤35mm; and / or, 0.5mm≤W2≤5mm; and / or, 5mm≤W3-W4≤40mm; and / or, L2≥L1; and / or, 5mm≤L1≤20mm; and / or, 5mm≤L2≤20mm. W1 is the size of the first pole lug groove in the second direction, W2 is the size of the first notch in the second direction, W3 is the size of the first safety layer in the second direction, W4 is the distance between the first notch and the first pole lug groove along the second direction, L1 is the size of the first pole lug groove in the third direction, and L2 is the size of the first notch in the third direction. The first direction, the second direction and the third direction are orthogonal to each other.

[0006] In a possible implementation, the first pole piece satisfies: 4.5 mm ≤ W1 ≤ 35 mm; and / or, 0.5 mm ≤ W5 ≤ 5 mm; and / or, W1-W5 ≥ 4 mm; and / or, L1-4 mm ≤ L3 ≤ L1+4 mm; and / or, L3 ≥ L4+0.5 mm. W1 is the size of the first pole lug groove in the second direction, W5 is the size of the second notch in the second direction, L1 is the size of the first pole lug groove in the third direction, L3 is the size of the second notch in the third direction, and L4 is the size of the first pole lug in the third direction. The first direction, the second direction, and the third direction are orthogonal to each other.

[0007] In a possible implementation manner, at least one of the first notch and the second notch is semicircular, semi-elliptical or polygonal.

[0008] In a possible implementation, at least one notch has a concave corner, and the concave corner is provided with a chamfer or a rounded corner; and / or the chamfer or the rounded corner is 0.5 to 3 mm.

[0009] In a possible implementation, the second surface has a second hollow foil area and a second layout area, the second layout area is provided with a second active layer, and the second hollow foil area is provided with a second safety layer. The second safety layer is provided with a first groove, and the orthographic projection of the first groove and the first tab groove along the first direction at least partially overlaps; or, the orthographic projection of the second safety layer along the first direction covers the orthographic projection of the first tab groove along the first direction.

[0010] In a possible implementation, the first active layer is provided with a second pole lug groove exposing a second portion of the first surface, and the second pole lug is connected to the second portion. The first pole piece is provided with a third notch, and the third notch and the second pole lug groove are arranged opposite to each other along the second direction; and / or the first pole piece is provided with a fourth notch, and the fourth notch is located at the edge of the second pole lug groove.

[0011] In a possible implementation, the first pole piece satisfies: 4.5mm≤W6≤35mm; and / or, 0.5mm≤W7≤5mm; and / or, 5mm≤W8-W9≤40mm; and / or, L6≥L5; and / or, 5mm≤L5≤20mm; and / or, 5mm≤L6≤20mm. W6 is the size of the second pole lug groove in the second direction, W7 is the size of the third notch in the second direction, W8 is the size of the first active layer in the second direction, W9 is the spacing between the third notch and the second pole lug groove along the second direction, L5 is the size of the second pole lug groove in the third direction, and L6 is the size of the third notch in the third direction. The first direction, the second direction, and the third direction are orthogonal to each other.

[0012] In a possible implementation, the first pole piece satisfies: 4.5 mm ≤ W6 ≤ 35 mm; and / or, 0.5 mm ≤ W10 ≤ 5 mm; and / or, L5-4 mm ≤ L7 ≤ L5 + 4 mm; and / or, L7 ≥ L8 + 0.5 mm. W6 is the size of the second pole lug slot in the second direction, W10 is the size of the fourth notch in the second direction, L5 is the size of the second pole lug slot in the third direction, L7 is the size of the fourth notch in the third direction, and L8 is the size of the second pole lug in the third direction. The first direction, the second direction, and the third direction are orthogonal to each other.

[0013] In a possible implementation manner, at least one of the third notch and the fourth notch is semicircular, semi-elliptical or polygonal.

[0014] In a possible implementation, at least one notch has a concave corner, and the concave corner is provided with a chamfer or a rounded corner; and / or the chamfer or the rounded corner is 0.5 to 3 mm.

[0015] In a possible implementation, the second surface has a second empty foil area and a second layout area, the second layout area is provided with a second active layer, and the second empty foil area is provided with a second security layer.

[0016] The second active layer is provided with a second groove, and the second groove and the orthographic projection of the second tab groove along the first direction at least partially overlap; or, the orthographic projection of the second active layer along the first direction covers the orthographic projection of the second tab groove along the first direction.

[0017] In a possible implementation, the first pole piece has a winding head located at the inner circle of the battery cell and a winding tail located at the outer circle of the battery cell, and the first empty foil area is located at the winding head and / or the winding tail.

[0018] In a possible implementation, the first electrode is a positive electrode, and the second electrode is a negative electrode.

[0019] In another aspect, an embodiment of the present invention provides a battery, which includes the battery cell according to the above aspect.

[0020] According to the battery cell and the battery provided by the embodiments of the utility model, since the first pole piece is provided with the first notch and / or the second notch, the safety risk will be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the positive side of the first pole piece according to an embodiment of the utility model.

[0022] Figure 2 for Figure 1 Schematic diagram of the structure of the back side of the first pole piece.

[0023] Figure 3 For along Figure 1 A schematic cross-sectional view taken along the AA plane in FIG.

[0024] Figure 4 To show Figure 1 Schematic diagram of the preparation process of the first electrode.

[0025] Figure 5 It is a schematic structural diagram of the back side of the first pole piece according to another embodiment of the utility model.

[0026] Figure 6 It is a structural schematic diagram of the positive side of the first pole piece according to another embodiment of the utility model.

[0027] Figure 7 for Figure 6 Schematic diagram of the structure of the back side of the first pole piece.

[0028] Figure 8 To show Figure 6 Schematic diagram of the preparation process of the first electrode.

[0029] Fig. 9 It is a schematic structural diagram of the back side of the first pole piece according to another embodiment of the utility model.

[0030] Fig.10 It is a structural schematic diagram of the positive side of the first pole piece according to another embodiment of the utility model.

[0031] Fig.11 for Fig.10 Schematic diagram of the structure of the back side of the first pole piece.

[0032] Fig.12 It is a schematic structural diagram of the back side of the first pole piece according to another embodiment of the utility model.

[0033] Fig.13 It is a structural schematic diagram of the positive side of the first pole piece according to another embodiment of the utility model.

[0034] Fig.14 for Fig.13 Schematic diagram of the structure of the back side of the first pole piece.

[0035] Fig.15 It is a schematic structural diagram of the back side of the first pole piece according to another embodiment of the utility model.

[0036] Fig.16 It is a structural schematic diagram of the positive side of the first pole piece according to another embodiment of the utility model.

[0037] Fig.17 for Fig.16 Schematic diagram of the structure of the back side of the first pole piece.

[0038] Fig.18 It is a schematic structural diagram of the back side of the first pole piece according to another embodiment of the utility model.

[0039] Fig.19 It is a structural schematic diagram of the positive side of the first pole piece according to another embodiment of the utility model.

[0040] Fig. 20 for Fig.19 Schematic diagram of the structure of the back side of the first pole piece.

[0041] Fig.21 It is a schematic structural diagram of the back side of the first pole piece according to another embodiment of the utility model.

[0042] Fig. 22 It is a structural schematic diagram of a notch according to an embodiment of the utility model.

[0043] Fig.23 It is a structural schematic diagram of a notch according to another embodiment of the utility model.

[0044] Fig.24 It is a structural schematic diagram of a notch according to another embodiment of the utility model.

[0045] Fig.25 It is a structural schematic diagram of a notch according to another embodiment of the utility model.

[0046] Fig.26 It is a structural schematic diagram of a notch according to another embodiment of the utility model.

[0047] Fig. 27 It is a structural schematic diagram of a notch according to another embodiment of the utility model.

[0048] Fig.28 It is a schematic structural diagram of a battery cell according to an embodiment of the utility model.

[0049] Fig.29 It is a schematic structural diagram of a battery cell according to another embodiment of the utility model.

[0050] Fig.30 It is a schematic structural diagram of a battery according to an embodiment of the utility model.

[0051] Fig.31 It is a schematic structural diagram of a battery according to another embodiment of the utility model. DETAILED DESCRIPTION

[0052] The following is a description of the embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the present invention can be implemented in a variety of ways and should not be construed as being limited to the embodiments described here. The embodiments described here are only for a more thorough and clear understanding of the present invention.

[0053] In this article, the first direction, second direction and third direction of the pole piece will be mentioned. The first direction refers to the stacking direction of the first current collector and the active layer, which is indicated by arrow Z in the figure. The third direction refers to the direction from the winding head of the pole piece to the winding tail thereof, which is indicated by arrow X in the figure. The second direction is a direction orthogonal to both the first direction and the third direction, which is indicated by arrow Y in the figure.

[0054] In this article, the winding head and winding tail of the pole piece are relative to their positions in the battery cell. In the battery cell, the winding head of the pole piece is located in the inner circle, and the winding tail of the pole piece is located in the outer circle.

[0055] In order to reduce safety risks, the embodiment of the present utility model provides a battery cell and a battery having the same. The battery cell includes a first pole piece, a second pole piece and a diaphragm, and the first pole piece and the second pole piece are wound with the diaphragm interposed therebetween. For example, the first pole piece may be a positive pole piece, and the second pole piece may be a negative pole piece. Below, in conjunction with the accompanying drawings, the first pole piece, the battery cell and the battery of the embodiment of the fundamental utility model are sequentially illustrated.

[0056] <Exemplary First Pole Piece>

[0057] According to an embodiment of the present invention, the first pole piece 10 is Figures 1 to 3 Reference Figures 1 to 3 The first pole piece 10 includes a first current collector 11, and the first current collector 11 has a first surface 111 and a second surface 112 relative to each other along a first direction. The first surface 111 has a first layout area S11 and a first empty foil area S12. By way of example only, the first empty foil area S12 can be located at the winding head and / or winding tail of the pole piece 10. In addition to being provided with the first active layer 12, in some examples of the utility model, the first layout area S11 can also be provided with a first safety layer 13; in this case, in the first layout area S11, the first safety layer 13 is located between the first active layer 12 and the first current collector 11, and at this time, the first safety layer provided in the first layout area S11 and the first empty foil area S12 can be integrally formed.

[0058] Due to the presence of the first safety layer 13, the risk of short circuit between the current collector 11 of the first pole piece 10 and the active layer of the second pole piece 20 or the current collector 21 of the second pole piece 20 will be reduced, which helps to reduce safety risks. In addition, the first safety layer 13 can also help improve the needle penetration rate and heavy object impact resistance of the battery cell.

[0059] Continue to refer Figure 1 The first safety layer 13 may be provided with a first tab groove 131, and the first tab groove 131 may expose a first portion 113 of the surface 111 of the first current collector 11. The first tab 14 may be connected to the first portion 113, for example, by welding.

[0060] Still refer to Figure 1 The first pole piece 10 may be provided with a first notch 101, and the first notch 101 and the first pole lug groove 131 are arranged opposite to each other along the second direction. In the first pole piece 10, the existence of the first notch 101 reduces the safety risk. The manufacturing process of the first pole piece 10 is briefly introduced below to illustrate this point.

[0061] refer to Figure 4 In the manufacturing process, a mother sheet 10-1 is first provided. Then, a plurality of mother grooves 130 spaced along the second direction are formed on the mother sheet 10-1, for example, by broadband cleaning. Then, the mother sheet 10-1 is cut into a plurality of preceding first pole sheets 10-2 along the cutting line, and at the same time, each mother groove 130 is cut into two parts. After the cutting is completed, two parts of two adjacent mother grooves 130 are left on the same preceding first pole sheet 10-2, forming a first pole lug groove 131 and a groove 132, and the groove 132 and the first pole lug groove 131 are arranged opposite to each other along the second direction.

[0062] The groove 132 exposes a surface portion 114 of the surface 111 of the first current collector 11. Due to the presence of the exposed surface portion 114, the risk of direct contact between the first current collector 11 and the second current collector 21 of the second pole piece 20 increases. Direct contact between the first current collector 11 and the second current collector 21 may cause fire and combustion, seriously affecting safety.

[0063] To reduce security risks, continue to refer to Figure 4 In a further process, the surface portion 114 is cut off to form a first notch 101, thereby obtaining the first pole piece 10. By cutting off the first notch 101 obtained by cutting off the surface portion 114, the risk of direct contact between the first current collector 11 and the second current collector 21 will be reduced, and the safety risk will be reduced.

[0064] refer to Figure 1 , along the second direction, the first pole tab groove 131 has a size W1. The size W1 may satisfy 4.5 mm ≤ W1 ≤ 35 mm. If the size W1 of the first pole tab groove 131 is too small, the first portion 113 is too small and it is difficult to provide sufficient area to connect with the first pole tab 14. If the size W1 of the first pole tab groove 131 is too large, the first portion 113 is too large, which increases the exposed area of ​​the first current collector 11 and increases the safety risk. The size W1 that meets the above conditions helps to ensure that the first portion 113 provides sufficient area to connect with the pole tab 14 without significantly increasing the safety risk.

[0065] Continue to refer Figure 1 , along the second direction, the first notch 101 has a size W2. The size W2 may satisfy 0.5 mm ≤ W2 ≤ 5 mm. If the size W2 of the first notch 101 is too small, it is difficult to ensure that the exposed surface portion 114 is completely cut off. If the size W2 of the first notch 101 is too large, the strength of the first pole piece 10 will be excessively weakened. The size W2 that meets the above conditions helps to ensure that the surface portion 114 is completely cut off without excessively weakening the strength of the first pole piece 10.

[0066] Continue to refer Figure 1 , along the second direction of the first pole piece 10, the first safety layer 13 has a size W3, and the first notch 101 and the first pole ear groove 131 have a spacing W4. The size W3 and the spacing W4 can satisfy 5mm≤W3-W4≤40mm. If W3-W4 is too large, it will either cause the size W1 to be too large or the size W2 to be too large; the former will increase the safety risk, and the latter will excessively weaken the strength of the first pole piece 10. If W3-W4 is too small, it will either cause the size W1 to be too small or the size W2 to be too small; the former is difficult to provide a sufficiently large first part 113 to connect with the pole ear 14, and the latter is difficult to ensure that the exposed surface part 114 is completely cut off. According to an embodiment of the utility model, 5mm≤W3-W4≤40mm, which can help the size W1 and the size W2 have a moderate size.

[0067] Continue to refer Figure 1 In a preferred example, the above conditions are met at the same time, that is, the first pole piece 10 simultaneously meets: 4.5mm≤W1≤35mm, 0.5mm≤W2≤5mm, and 5mm≤W3-W4≤40mm. In this way, the surface portion 114 will be completely cut off, the first pole piece 10 will have sufficient strength, the first portion 113 will provide sufficient area to connect with the pole lug 14, and the safety risk will be relatively small.

[0068] Continue to refer Figure 1 , along the third direction, the first tab groove 131 has a size L1, and the first notch 101 has a size L2. The size L1 and the size L2 may satisfy L2 ≥ L1. In this way, the exposed surface portion 114 will be completely removed. Preferably, the size L1 may be in a range of 5 mm ≤ L1 ≤ 20 mm, and the size L2 may be in a range of 5 mm ≤ L2 ≤ 20 mm. In this way, the first tab groove 131 will have a sufficient size to receive the tab 14.

[0069] refer to Figure 2 and Figure 3The second surface 112 of the first current collector 11 may include a second layout area S21 and a second empty foil area S22. The second layout area S21 is provided with a second active layer 15, and the second empty foil area S22 is provided with a second safety layer 16. By way of example only, the second empty foil area S22 may be located at the winding head and / or winding tail of the pole piece 10.

[0070] By laying out the second safety layer 16, the risk of short circuit caused by direct contact between the current collector 11 of the first pole piece 10 and the current collector 21 of the second pole piece 20 will be reduced, which helps to reduce safety risks. In addition, the second safety layer 16 can also help improve the needle penetration rate and heavy object impact resistance of the battery cell.

[0071] refer to Figure 1 and 2 The second safety layer 16 may be provided with a first groove 161, and the first groove 161 and the orthographic projection of the first tab groove 131 along the first direction at least partially overlap. Due to the existence of the first groove 161, the tab 14 can be connected to the first portion 113 by some means, such as ultrasonic welding, by utilizing the exposed surface portion 115 thereof.

[0072] According to another embodiment of the present invention, the first pole piece 10a is Figure 5 The first pole piece 10a has a similar structure to the first pole piece 10. The difference is mainly that, Figure 5 In the first pole piece 10a, the second safety layer 16 is not provided with the first groove 161, but the orthographic projection of the second safety layer 16 along the first direction covers the orthographic projection of the first pole ear groove 131 along the first direction. This structure helps to reduce safety risks by reducing the exposed surface of the first current collector 11. By way of example only, for the first pole piece 10a, the pole ear 14 can be connected to the first part 113 by means of conductive adhesive bonding or laser welding.

[0073] According to another embodiment of the present invention, the first pole piece 10b is Figure 6 and Figure 7 The first pole piece 10b has a similar structure to the first pole piece 10, and the difference between the two will be described in detail below. Figure 6 and Figure 7 The first pole piece 10b is provided with a second notch 102, and the second notch 102 is located at the edge of the first pole lug groove 131. In the first pole piece 10b, the presence of the notch 101 reduces the safety risk. The manufacturing process of the first pole piece 10b is briefly introduced below to illustrate this point.

[0074] refer to Figure 8In the manufacturing process of the first pole piece 10b, the slitting line of the mother piece 10-1b does not pass through the mother groove 130. Therefore, the mother groove 130 is not slit. After slitting, on the preceding pole piece 10-2b, the mother groove 130 does not extend to the edge, which results in a residual portion 133 of the first safety layer 13 between the mother groove 130 and the edge.

[0075] If the residual portion 133 is retained on the first pole piece 10b, it will lead to an unreasonable structure and increase safety risks. Specifically, after the pole ear 14 is fixed, the pole ear 14 will be stacked with the residual portion 133, which will cause the pole ear 14 to form a bulge at the stacking position. The presence of the bulge increases the risk of diaphragm damage, thereby increasing the risk of short circuit between the two pole pieces 10 and 20. If the two pole pieces 10 and 20 are short-circuited, it will cause fire and seriously affect safety. In addition, the presence of the bulge increases the thickness of the first pole piece 10b and reduces the energy density.

[0076] To reduce security risks, continue to refer to Figure 8 In a further process, the residual portion 133 is cut off to form the first tab groove 131 and the second notch 102 at the edge thereof. According to the second notch 102 obtained by cutting off the residual portion 133, the tab 14 will not form a convex portion due to stacking with the residual portion 133, which helps to reduce safety risks and improve energy density.

[0077] refer to Figure 6 , along the second direction, the first pole tab groove 131 has a size W1. The size W1 may satisfy 4.5 mm ≤ W1 ≤ 35 mm. If the size W1 of the first pole tab groove 131 is too small, the first portion 113 is too small and it is difficult to provide sufficient area to connect with the pole tab 14. If the size W1 of the first pole tab groove 131 is too large, the first portion 113 is too large, which increases the exposed area of ​​the first current collector 11 and increases the safety risk. The size W1 that meets the above conditions helps to ensure that the first portion 113 provides sufficient area to connect with the pole tab 14 without significantly increasing the safety risk.

[0078] Continue to refer Figure 6 , along the second direction, the second notch 102 has a size W5. The size W5 may satisfy 0.5 mm ≤ W5 ≤ 5 mm. If the size W5 of the second notch 102 is too small, the stacking phenomenon of the first pole tab 14 is difficult to avoid. If the size W5 of the second notch 102 is too large, the strength of the first pole piece 10b will be too much weakened. The size W5 that meets the above conditions helps to avoid the stacking phenomenon without too much weakening the strength of the first pole piece 10b.

[0079] Continue to refer Figure 6, the size W1 and the size W5 can satisfy W1-W5≥4mm. Accordingly, after punching the second notch 102 , the size of the first portion 113 exposed by the first tab groove 131 along the width direction of the pole piece 10 is still not less than 4mm, ensuring that it has sufficient size to connect with the second tab 14 .

[0080] Continue to refer Figure 6 , along the third direction, the first pole lug groove 131 has a size L1, and the second notch 102 has a size L3. The size L1 and the size L3 can satisfy L1-4 mm≤L3≤L1+4mm. If the size L3 is too large compared to the size L1, too much of the first pole piece 10b is cut off, which will weaken the strength of the first pole piece 10b too much. If the size L3 is too small compared to the size L1, stacking may occur, which will increase the safety risk. The size L1 and the size L3 that meet the above conditions help to avoid stacking without significantly weakening the strength of the first pole piece 10b. Specifically, L1 can be greater than or equal to L3, so that the strength of the pole lug groove position can be ensured; of course, L1 can also be less than or equal to L3, so that the cutting position can be ensured to be located on the safety layer when punching the notch, avoiding the generation of more burrs.

[0081] Continue to refer Figure 6 , along the third direction, the pole ear 14 has a size L4. The size L3 and the size L4 can satisfy L3 ≥ L4 + 0.5 mm. In this way, in the third direction of the first pole piece 10, the second notch 102 will be slightly larger than the pole ear 14, which helps to avoid stacking.

[0082] Continue to refer Figure 6 In a preferred example, the above conditions are satisfied at the same time, that is, the first pole piece 10b satisfies: L1-4 mm≤L3≤L1+4 mm, and L3≥L4+0.5 mm. In this way, the strength of the first pole piece 10c is relatively high, and the safety risk is relatively small.

[0083] According to another embodiment of the present invention, the first pole piece 10c is Fig. 9 The first pole piece 10c has a similar structure to the first pole piece 10b. The difference is mainly that, Fig. 9 In the first pole piece 10c, the second safety layer 16 is not provided with the first groove 161, but the orthographic projection of the second safety layer 16 along the first direction covers the orthographic projection of the first pole lug groove 131 along the first direction. This structure reduces the exposed surface of the first current collector 11, thereby helping to reduce safety risks.

[0084] According to another embodiment of the present invention, the first pole piece 10d is Fig.10 and Fig.11 Reference Fig.10 and Fig.11 , the first pole piece 10d has a first notch 101 and a second notch 102. The first notch 101 and the first pole tab slot 131 are arranged opposite to each other along the second direction, and the second notch 102 is located at the edge of the first pole tab slot 131. The dimensions of the first notch 101, the second notch 102 and the first pole tab slot 131 in each direction can refer to the above examples, and will not be repeated here.

[0085] Due to errors in the manufacturing process, the slitting line may or may not pass through the mother groove 130. Therefore, after slitting, there may be both the groove 132 and the residual part 133. If only the first notch 101 or the second notch 102 is provided, it is difficult to eliminate the safety risk. According to the first pole piece 10d provided in the embodiment of the utility model, since the first pole piece 10d has the first notch 101 and the second notch 102, both the groove 132 and the residual part 133 will be removed, which helps to further reduce the safety risk.

[0086] According to another embodiment of the present invention, the first pole piece 10e is Fig.12 The first pole piece 10e has a similar structure to the first pole piece 10d described above. The main difference is that, Fig.12 In the first pole piece 10e, the second safety layer 16 is not provided with the first groove 161, but the orthographic projection of the second safety layer 16 along the first direction covers the orthographic projection of the first pole lug groove 131 along the first direction. This structure reduces the exposed surface of the first current collector 11, thereby helping to reduce safety risks.

[0087] According to other embodiments of the present invention, the first pole piece 10f is Fig.13 and Fig.14 Reference Fig.13 and Fig.14 In the first pole piece 10f, the first active layer 12 may be provided with a second pole lug groove 121, the second pole lug groove 121 may expose the second portion 116 of the surface 111 of the first current collector 11, and the second pole lug 17 may be connected to the second portion 116, for example, by welding. By adding the second pole lug 17, the current carrying capacity of the pole piece 10f will be improved, which helps to improve the charge and discharge performance of the battery.

[0088] Continue to refer Fig.13 The first pole piece 10f may also be provided with a third notch 103, and the third notch 103 and the second pole lug groove 121 are arranged opposite to each other along the second direction. Similar to the role played by the first notch 101, the third notch 103 also helps to reduce safety risks.

[0089] refer to Fig.13, along the second direction, the second pole tab groove 121 has a size W6. The size W6 may satisfy 4.5 mm ≤ W6 ≤ 35 mm. If the size W6 of the second pole tab groove 121 is too small, the second portion 116 is too small to provide sufficient area for connection with the second pole tab 17. If the size W6 of the second pole tab groove 121 is too large, the second portion 116 is too large, which increases the exposed area of ​​the first current collector 11 and increases the safety risk. The size W6 that meets the above conditions helps ensure that the second portion 116 provides sufficient area for connection with the second pole tab 17 without significantly increasing the safety risk.

[0090] Continue to refer Fig.13 , along the second direction, the third notch 103 has a size W7. The size W7 may satisfy 0.5 mm ≤ W7 ≤ 5 mm. If the size W7 of the third notch 103 is too small, it is difficult to ensure that the corresponding exposed surface portion is completely cut off. If the size W7 of the third notch 103 is too large, the strength of the first pole piece 10f will be excessively weakened. The size W7 that meets the above conditions helps to ensure that the corresponding surface portion is completely cut off without excessively weakening the strength of the first pole piece 10f.

[0091] Continue to refer Fig.13 , along the second direction, the first active layer 12 has a size W8, and the third notch 103 and the second pole ear groove 121 have a spacing W9. The size W8 and the spacing W9 can satisfy 5mm≤W8-W9≤40mm. If W8-W9 is too large, it will either cause the size W6 to be too large or the size W7 to be too large; the former will increase the safety risk, and the latter will excessively weaken the strength of the first pole piece 10f. If W8-W9 is too small, it will either cause the size W6 to be too small or the size W7 to be too small; the former is difficult to provide a sufficiently large second part 116 to connect with the second pole ear 17, and the latter is difficult to ensure that the corresponding exposed surface part is completely cut off. According to an embodiment of the utility model, 5mm≤W8-W9≤40mm, which can help the size W6 and the size W7 have a moderate size.

[0092] Continue to refer Fig.13 In a preferred example, the above conditions are met at the same time, that is, the first pole piece 10f meets the following conditions: 4.5mm≤W6≤35mm, 0.5mm≤W7≤5mm, and 5mm≤W8-W9≤40mm. In this way, the corresponding surface portion will be completely cut off, the first pole piece 10f will have sufficient strength, the second portion 116 provides sufficient area to connect with the second pole lug 17, and the safety risk is relatively small.

[0093] Continue to refer Fig.13, along the third direction, the second pole tab slot 121 has a size L5, and the third notch 103 has a size L6. The size L5 and the size L6 may satisfy L6 ≥ L5. In this way, the corresponding exposed surface portion will be completely removed. Preferably, the value range of the size L5 may be 5mm≤L5≤20mm, and the value range of the size L6 may be 5mm≤L6≤20mm. In this way, the second pole tab slot 121 will have a sufficient size to receive the second pole tab 17.

[0094] refer to Fig.14 In the first pole piece 10f, the second active layer 15 may be provided with a second groove 151, and the second groove 151 and the orthographic projection of the second pole tab groove 121 along the first direction at least partially overlap. Due to the existence of the second groove 151, the second pole tab 17 can be connected to the second portion 116 by some means, such as ultrasonic welding, by utilizing the exposed surface portion 17 thereof.

[0095] According to another embodiment of the present invention, the first pole piece 10g is Fig.15 The first pole piece 10g has a similar structure to the first pole piece 10f. The difference is mainly that, Fig.15 In the first pole piece 10g, the second active layer 15 is not provided with the second groove 151, but the orthographic projection of the second active layer 15 along the first direction covers the orthographic projection of the second pole lug groove 121 along the first direction. This structure helps to reduce safety risks by reducing the exposed surface of the first current collector 11. By way of example only, for the first pole piece 10g, the second pole lug 17 can be connected to the second portion 116 by means of conductive adhesive bonding or laser welding.

[0096] According to another embodiment of the present invention, the first pole piece 10h is Fig.16 and Fig.17 Reference Fig.16 and Fig.17 The first pole piece 10h is provided with a fourth notch 104, and the fourth notch 104 is located at the edge of the second pole lug groove 121. Similar to the function of the second notch 102, the fourth notch 104 helps to reduce safety risks and improve energy density.

[0097] Continue to refer Fig.16, along the second direction, the second pole tab groove 121 has a size W6. The size W6 may satisfy 4.5 mm ≤ W6 ≤ 35 mm. If the size W6 of the second pole tab groove 121 is too small, the second portion 116 is too small to provide sufficient area for connection with the second pole tab 17. If the size W6 of the second pole tab groove 121 is too large, the second portion 116 is too large, which increases the exposed area of ​​the first current collector 11 and increases the safety risk. The size W6 that meets the above conditions helps ensure that the second portion 116 provides sufficient area for connection with the second pole tab 17 without significantly increasing the safety risk.

[0098] Continue to refer Fig.16 , along the second direction, the fourth notch 104 has a size W10. The size W10 may satisfy 0.5 mm ≤ W10 ≤ 5 mm. If the size W10 of the fourth notch 104 is too small, the stacking phenomenon of the second pole tab 17 is difficult to avoid. If the size W10 of the fourth notch 104 is too large, the strength of the first pole piece 10h will be excessively weakened. The size W10 that meets the above conditions helps to avoid the stacking phenomenon without excessively weakening the strength of the first pole piece 10h.

[0099] Continue to refer Fig.16 , along the third direction, the second pole ear groove 121 has a size L5, and the fourth notch 104 has a size L7. The size L5 and the size L7 can satisfy L5-4 mm≤L7≤L5+4 mm. If the size L7 is too large compared to the size L5, too much of the first pole piece 10h is cut off, which will excessively weaken the strength of the first pole piece 10h. If the size L7 is too small compared to the size L5, stacking may occur, which will increase the safety risk. The size L5 and the size L7 that meet the above conditions help to avoid stacking without significantly weakening the strength of the first pole piece 10h.

[0100] Continue to refer Fig.16 , along the third direction, the second pole tab 17 has a size L8. The size L8 and the size L7 may satisfy L7≥L8+0.5 mm. Thus, in the third direction, the fourth notch 104 will be slightly larger than the second pole tab 17, which helps to avoid stacking.

[0101] Continue to refer Fig.16 In a preferred example, the above conditions are satisfied at the same time, that is, the first pole piece 10h satisfies: L5-4 mm≤L7≤L5+4 mm, and L7≥L8+0.5 mm. In this way, the strength of the first pole piece 10h is relatively high, and the safety risk is relatively small.

[0102] According to another embodiment of the present invention, the first pole piece 10i is Fig.18 The first pole piece 10i and the first pole piece 10h have similar structures. The difference is mainly that, Fig.18 In the first pole piece 10i, the second active layer 15 is not provided with the second groove 151, but the orthographic projection of the second active layer 15 along the first direction covers the orthographic projection of the second pole lug groove 121 along the first direction. This structure reduces the exposed surface of the first current collector 11, thereby helping to reduce safety risks.

[0103] According to another embodiment of the present invention, the first pole piece 10j is Fig.19 and Fig. 20 Reference Fig.19 and Fig. 20 , the first pole piece 10j has a third notch 103 and a fourth notch 104. The third notch 103 and the second pole tab slot 121 are arranged opposite to each other along the second direction, and the fourth notch 104 is located at the edge of the second pole tab slot 121. The dimensions of the third notch 103, the fourth notch 104 and the second pole tab slot 121 in each direction can refer to the above examples, and will not be repeated here. Similar to the functions of the first notch 101 and the second notch 102 that exist at the same time, the third notch 103 and the fourth notch 104 that exist at the same time help to further reduce safety risks.

[0104] According to another embodiment of the present invention, the first pole piece 10k is Fig.21 The first pole piece 10k has a similar structure to the first pole piece 10j described above. The main difference is that Fig.21 In the first pole piece 10k, the second active layer 15 is not provided with the second groove 151, but the orthographic projection of the second active layer 15 along the first direction covers the orthographic projection of the second pole lug groove 121 along the first direction. This structure reduces the exposed surface of the first current collector 11, thereby helping to reduce safety risks.

[0105] There are many options for the shapes of the notches 101 to 104, and the embodiments of the present invention do not impose any particular restrictions on this. Fig. 22 As shown, the notches 101-104 may be semicircular. As another example, Fig.23 As shown, the notches 101-104 may be semi-elliptical. As another example, Fig.24 and Fig.25 As shown, the notches 101-104 may be in the form of trapezoids, rectangles or other polygons. Fig.26 and Fig. 27 As shown, the concave corners 105 of the notches 101 to 104 may be chamfered or rounded to avoid stress concentration and reduce the risk of damage at the notches 101 to 104. Preferably, the size of the chamfer or rounded corner is 0.5 mm to 3 mm.

[0106] By way of example only, the first current collector in the above example may be a strip of metal foil. By way of example only, the metal foil mentioned here may be aluminum foil.

[0107] By way of example only, the first and second active material layers in the aforementioned examples may include positive electrode active materials that can reversibly absorb and release charge carriers. In addition, the active material layer may further include conductive materials, binders, and various additives. By way of example only, the positive electrode active material mentioned here may be a lithium transition metal composite oxide such as lithium nickel cobalt manganese composite oxide, the conductive material mentioned may be a carbon material such as acetylene black, and the binder mentioned may be polyvinylidene fluoride, etc.

[0108] By way of example only, the first and second safety layers in the aforementioned examples may include an inorganic filler, a conductive agent, and a binder. By way of example only, the inorganic filler mentioned here may be selected from one or more of lithium cobalt oxide (LCO), nickel cobalt manganese ternary material (NCM), nickel cobalt aluminum ternary material (NCA), nickel cobalt manganese aluminum quaternary material (NCMA), lithium iron phosphate (LFP), carbon-coated lithium iron phosphate (C-LFP), lithium manganese phosphate (LMP), lithium manganese oxide (LMO), and lithium-rich manganese base; or, the inorganic filler mentioned here may be selected from ceramic materials, for example, may be selected from one or more of aluminum oxide, boehmite, magnesium oxide, and magnesium hydroxide; or, the inorganic filler mentioned here may be selected from a mixture of at least one of lithium-containing transition metal oxides and at least one of ceramic materials. By way of example only, the conductive agent mentioned here may be selected from one or more of conductive carbon black, acetylene black, conductive graphite, Ketjen black, carbon nanotubes, and graphene. Merely by way of example, the binder mentioned here can be selected from one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl pyrrolidone, polyacrylic acid, polyacrylonitrile, lithium polyacrylate, polyamide, methacrylate, and sodium carboxymethyl cellulose.

[0109] <Exemplary battery cell>

[0110] The present utility model also provides a battery cell, which may include the pole piece mentioned above. Fig.28 and Fig.29 , the battery cell provided in the embodiment of the utility model is illustrated by way of example.

[0111] According to an embodiment of the present invention, the battery cell 100 is Fig.28 Reference Fig.28 , the battery cell 100 may include the first pole piece 10 described above. In the battery cell 100, the first pole piece 10 may be replaced by any one of the first pole pieces 10a-e. Fig.28, the battery cell 100 may further include a second pole piece 20 and a separator 30. The first pole piece 10 and the second pole piece 20 have opposite polarities. The second pole piece 20 may have a second current collector 21 and an active layer 22 disposed thereon. For example, the first pole piece 10 may be a positive pole piece, and the second pole piece 20 may be a negative pole piece. The first pole piece 10 and the second pole piece 20 may be wound across the separator 30 to form a flat structure. The first pole piece 10 may have a first pole ear 14, and the second pole piece 20 may have a pole ear 24. The first pole piece 10 may also be affixed with a plurality of insulating protective tapes 15, and the plurality of insulating protective tapes may cover the edges of the first pole ear 14 and the active material layer. Similarly, the pole piece 20 may also be affixed with a plurality of insulating protective tapes 25, and the plurality of insulating protective tapes may cover the edges of the pole ear 24 and the active material layer.

[0112] According to an embodiment of the present invention, the battery cell 100a is Fig.29 Reference Fig.29 , the battery cell 100a may include the first pole piece 10f introduced above. In the battery cell 100, the first pole piece 10f may be replaced by any one of the pole pieces 10g~k. The first pole piece 10f may have a first pole ear 14 and a second pole ear 17, and the second pole piece 20 may have a pole ear 24. The first pole piece 10f may also be pasted with a plurality of insulating protective tapes 15, and the plurality of insulating protective tapes may cover the edges of the first pole ear 14, the second pole ear 17 and the active material layer 12. Similarly, the second pole piece 20 may also be pasted with a plurality of insulating protective tapes 25, and the plurality of insulating protective tapes may cover the edges of the pole ear 24 and the active material layer of the second pole piece 20.

[0113] It is understood that the above description of the battery cell provided by the embodiment of the utility model is exemplary, and the battery cell provided by the utility model is not limited to the example. In some examples, battery cells in other shapes are foreseeable.

[0114] <Exemplary Battery>

[0115] The present utility model also provides a battery, which includes the battery cell mentioned above. Fig.30 and Fig.31 , the battery provided in the embodiment of the utility model is illustrated by way of example.

[0116] It should be noted that, in this article, "battery" refers to a storage device that can be repeatedly charged and discharged, which can be interpreted as the concept of "secondary battery". In the present utility model, the concept of "secondary battery" can include, but is not limited to, lithium-ion secondary batteries, sodium-ion secondary batteries, and nickel-hydrogen batteries.

[0117] According to an embodiment of the present invention, a battery 200 is Fig.30 Reference Fig.30The battery 200 may include a battery cell 100. In the battery 200, the battery cell 100 may be replaced with a battery cell 100a. The battery 200 may further include a packaging body 300. The packaging body 300 may be provided with a cavity, and one or more battery cells 100 may be accommodated in the cavity.

[0118] like Fig.30 As shown, the package 300 may be square. That is, the battery 200 may be a square battery. The material of the package 300 may be the same as that used in the past, and there is no particular limitation. For example, the package 300 may be made of metal, in particular, may be made of aluminum (alloy) or iron (alloy).

[0119] According to another embodiment of the present invention, a battery 200a is Fig.31 As shown in Fig.31 As shown, in this embodiment, the packaging body 300 is flat and made of a relatively soft material, such as an aluminum-plastic film. That is, in this embodiment, the battery 200a can be a soft-pack battery.

[0120] It is foreseeable that in other examples of the present invention, the battery may also be implemented as other types besides the square battery and the soft pack battery.

[0121] It should be noted that the structure of other aspects of the battery can be the same as the conventional battery structure, and for the purpose of brevity, the present invention will not elaborate on this.

[0122] It should be understood that the term "including" and its variations used in the present invention are open inclusions, i.e., "including but not limited to". The term "according to" means "at least in part according to". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least another embodiment".

[0123] It should be understood that although the terms "first" or "second" etc. may be used in the present invention to describe various elements, such as a first groove and a second groove, these elements are not defined by these terms, which are only used to distinguish one element from another.

[0124] The protection scope of the present invention is not limited to the above embodiments. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A battery cell, characterized in that: The invention comprises a first pole piece and a second pole piece wound with a diaphragm therebetween, wherein the first pole piece comprises a first current collector, the first current collector has a first surface and a second surface opposite to each other along a first direction, the first surface has a first empty foil area and a first layout area, the first layout area is provided with a first active layer, the first empty foil area is provided with a first safety layer, the first safety layer is provided with a first pole ear groove exposing a first part of the first surface, and the first pole ear is connected to the first part, wherein: The first pole piece is provided with a first notch, and the first pole lug groove and the first notch are arranged opposite to each other along a second direction, wherein the first direction and the second direction are orthogonal; and / or The first pole piece is provided with a second notch, and the second notch is located at the edge of the first pole lug groove.

2. The battery cell according to claim 1, characterized in that: The first pole piece satisfies: 4.5mm≤W1≤35mm; and / or 0.5mm≤W2≤5mm; and / or 5mm≤W3-W4≤40mm; and / or L2 ≥ L1; and / or 5mm≤L1≤20mm; and / or 5mm≤L2≤20mm, Among them, W1 is the size of the first pole lug groove in the second direction, W2 is the size of the first notch in the second direction, W3 is the size of the first safety layer in the second direction, W4 is the distance between the first notch and the first pole lug groove along the second direction, L1 is the size of the first pole lug groove in the third direction, L2 is the size of the first notch in the third direction, wherein the first direction, the second direction and the third direction are orthogonal to each other.

3. The battery cell according to claim 1, characterized in that: The first pole piece satisfies: 4.5mm≤W1≤35mm; and / or 0.5mm≤W5≤5mm; and / or W1-W5 ≥ 4 mm; and / or L1-4 mm ≤ L3 ≤ L1+4 mm; and / or L3≥L4+0.5mm, Among them, W1 is the size of the first pole lug groove in the second direction, W5 is the size of the second notch in the second direction, L1 is the size of the first pole lug groove in the third direction, L3 is the size of the second notch in the third direction, and L4 is the size of the first pole lug in the third direction, wherein the first direction, the second direction and the third direction are orthogonal to each other.

4. The battery cell according to any one of claims 1 to 3, characterized in that: At least one of the first notch and the second notch is semicircular, semi-elliptical or polygonal.

5. The battery cell according to claim 4, characterized in that: The at least one notch has a concave corner, and the concave corner is provided with a chamfer or a rounded corner; and / or The chamfer or rounded corner is 0.5 to 3 mm.

6. The battery cell according to any one of claims 1 to 3, characterized in that: The second surface has a second empty foil area and a second layout area, the second layout area is provided with a second active layer, and the second empty foil area is provided with a second security layer, wherein: The second safety layer is provided with a first groove, and the orthographic projection of the first groove and the first tab groove along the first direction at least partially overlaps; or The orthographic projection of the second safety layer along the first direction covers the orthographic projection of the first electrode tab groove along the first direction.

7. The battery cell according to claim 1, characterized in that: The first active layer is provided with a second electrode tab groove exposing a second portion of the first surface, and the second electrode tab is connected to the second portion, wherein The first pole piece is provided with a third notch, and the third notch and the second pole lug groove are arranged opposite to each other along the second direction; and / or The first pole piece is provided with a fourth notch, and the fourth notch is located at the edge of the second pole lug groove.

8. The battery cell according to claim 7, characterized in that: The first pole piece satisfies: 4.5mm≤W6≤35mm; and / or 0.5mm≤W7≤5mm; and / or 5mm≤W8-W9≤40mm; and / or L6 ≥ L5; and / or 5mm≤L5≤20mm; and / or 5mm≤L6≤20mm, Among them, W6 is the size of the second pole lug groove in the second direction, W7 is the size of the third notch in the second direction, W8 is the size of the first active layer in the second direction, W9 is the distance between the third notch and the second pole lug groove along the second direction, L5 is the size of the second pole lug groove in the third direction, and L6 is the size of the third notch in the third direction, wherein the first direction, the second direction and the third direction are orthogonal to each other.

9. The battery cell according to claim 7, characterized in that: The first pole piece satisfies: 4.5mm≤W6≤35mm; and / or 0.5mm≤W10≤5mm; and / or L5-4 mm ≤ L7 ≤ L5+4 mm; and / or L7 ≥ L8 + 0.5 mm, Among them, W6 is the size of the second pole lug groove in the second direction, W10 is the size of the fourth notch in the second direction, L5 is the size of the second pole lug groove in the third direction, L7 is the size of the fourth notch in the third direction, and L8 is the size of the second pole lug in the third direction, wherein the first direction, the second direction and the third direction are orthogonal to each other.

10. The battery cell according to any one of claims 7 to 9, characterized in that: At least one of the third notch and the fourth notch is semicircular, semi-elliptical or polygonal.

11. The battery cell according to claim 10, characterized in that: The at least one notch has a concave corner, and the concave corner is provided with a chamfer or a rounded corner; And / or, the chamfer or rounded corner is 0.5 to 3 mm.

12. The battery cell according to any one of claims 7 to 9, characterized in that: The second surface has a second empty foil area and a second layout area, the second layout area is provided with a second active layer, and the second empty foil area is provided with a second security layer, wherein: The second active layer is provided with a second groove, and the orthographic projection of the second groove and the second tab groove along the first direction at least partially overlaps; or The orthographic projection of the second active layer along the first direction covers the orthographic projection of the second electrode tab groove along the first direction.

13. The battery cell according to claim 1, characterized in that: The first pole piece has a winding head portion located at the inner circle of the battery cell and a winding tail portion located at the outer circle of the battery cell, and the first empty foil area is located at the winding head portion and / or the winding tail portion.

14. The battery cell according to claim 1, characterized in that: The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

15. A battery, characterized in that: Comprising the battery cell according to claim 14.

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