Battery cell, battery and electric device

Abstract

The utility model relates to a battery cell, a battery and an electric device. The battery cell comprises a battery cell body, the battery cell body comprises a positive plate, a negative plate and a diaphragm for separating the positive plate from the negative plate, and the positive plate comprises a first current collector and a first active material layer; the negative plate comprises a second current collector and a second active material layer; the first current collector and the second current collector are current collectors, each current collector comprises a non-coating part and a coating part, and the thickness of each non-coating part is greater than that of each coating part; the coating part extends along a first direction; the non-coating part is arranged on one side of the coating part in the first direction; in the first direction, one end of the non-coating part is connected with the coating part; the end face of the other end of the non-coating part is a connecting face used for being attached to and connected with an adapter piece. The thickness of the non-coating part is increased, and the connecting area of the non-coating part and the connecting piece is increased, so that the non-coating part adapts to the rubbing process and has better overflowing capacity.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cell, a battery and an electrical device. Background Art

[0002] In battery production, the originally vertical tabs are flattened through the tab flattening process, so that the tabs are in contact with each other and are in the same plane after flattening to facilitate welding; however, due to the thin thickness of existing battery tabs, they are very easy to fold and tear during flattening, resulting in tab wrinkles, affecting the electrical connection strength between the tabs and the connecting pieces, and further affecting the current carrying capacity of the connection; at the same time, thinner tabs are also prone to produce metal chips during flattening, which requires a high flattening speed and causes many inconveniences. Utility Model Content

[0003] To this end, the technical problem to be solved by the utility model is to overcome the technical difficulties in the prior art such as the fact that the pole ear is too thin to be flattened, resulting in insufficient connection strength between the pole ear and the connecting piece, and to provide a battery cell, a battery and an electrical device, which can increase the thickness of the pole ear so that the end face of the pole ear and the connecting piece are electrically connected, while improving the current carrying capacity.

[0004] In a first aspect, in order to solve the above technical problems, the utility model provides a battery cell, wherein the battery cell comprises a battery cell body,

[0005] The battery cell body includes a positive electrode sheet, a negative electrode sheet, and a separator used to separate the positive electrode sheet from the negative electrode sheet. The positive electrode sheet includes a first current collector and a first active material layer; the negative electrode sheet includes a second current collector and a second active material layer; the first current collector and the second current collector are both current collectors.

[0006] The current collector includes a non-coating portion and a coating portion, the thickness of the non-coating portion is H1, and the thickness of the coating portion is H2, satisfying: H2

[0007] In one embodiment of the present invention, the thickness of the first active material layer is a, the thickness of the second active material layer is b, and the thickness of the separator is c, satisfying H1≤2a+2b+2c+2H2.

[0008] In an embodiment of the present invention, the length of the non-coating portion in the first direction is d1, 10mm≤d1≤50mm; the length of the coating portion in the first direction is d2, 100mm≤d2≤500mm. ​

[0009] In one embodiment of the present invention, the battery cell body is a wound battery cell, a plurality of the non-coating portions are provided, and the plurality of the non-coating portions are stacked in sequence along a second direction, and the second direction is a thickness direction of the battery cell body.

[0010] In one embodiment of the present invention, the battery cell body is a laminated battery cell, a plurality of current collectors are provided, and the non-coated portions of the plurality of current collectors are stacked in sequence along a second direction, and the second direction is a thickness direction of the battery cell body.

[0011] In one embodiment of the utility model, the non-coating portion includes a first base film layer and two first metal layers, and the two first metal layers are respectively arranged on both sides of the thickness direction of the first base film layer; the coating portion includes a second base film layer and two second metal layers, and the two second metal layers are respectively arranged on both sides of the thickness direction of the second base film layer; the first base film layer and the second base film layer are connected as a whole; the first metal layer and the second metal layer are connected as a whole, wherein the thickness of the first base film layer is the same as the thickness of the second base film layer, and the thickness of the first metal layer is greater than the thickness of the second metal layer.

[0012] In an embodiment of the present invention, the non-coated portion is a first foil substrate, the coated portion is a second foil substrate, and the first foil substrate and the second foil substrate are connected as one body.

[0013] In one embodiment of the utility model, the non-coated portion includes a third foil substrate and a pole lug sleeve, the coated portion is a fourth foil substrate, the third foil substrate and the fourth foil substrate are connected as a whole, wherein the thickness of the third foil substrate is equal to the thickness of the fourth foil substrate; the pole lug sleeve is arranged on the outside of the third foil substrate.

[0014] In a second aspect, the utility model also provides a battery, which includes two adapter plates with opposite polarities and the battery cell described in any of the above embodiments, the adapter plate includes a first adapter surface perpendicular to the first direction, and the first adapter surface with the same polarity is adhered and connected to the connecting surface of the non-coated part.

[0015] In a third aspect, the utility model further provides an electrical device, which includes the battery described in the above embodiment.

[0016] The above technical solution of the utility model has the following advantages compared with the prior art:

[0017] The battery cell, battery and electrical device described in the utility model improve the structural strength of the tab by increasing the thickness of the non-coated part of the battery cell body, and increase the area of ​​connection between the tab and the connecting sheet, so that the tab can adapt to the flattening process and have better current carrying capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the content of the utility model easier to understand, the utility model is further described in detail according to the specific embodiments of the utility model in combination with the accompanying drawings, wherein:

[0019] Figure 1 This is a schematic cross-sectional structure diagram of a current collecting member in Embodiment 1 of the present utility model;

[0020] Figure 2 This is a schematic cross-sectional structure diagram of a pole piece in Embodiment 1 of the present utility model;

[0021] Figure 3 It is a schematic cross-sectional structure diagram of another pole piece in the first embodiment of the utility model;

[0022] Figure 4 This is a schematic diagram of a portion of the structure of the battery cell body in the thickness direction in the first embodiment of the utility model;

[0023] Figure 5 for Figure 4 An enlarged schematic diagram of one side of the middle pole ear;

[0024] Figure 6 This is a schematic diagram of the structure of a battery in Embodiment 3 of the present utility model.

[0025] Description of the Figures in the Specification:

[0026] 1. Cell body; 11. Positive electrode sheet; 1101. First current collector; 1102. First active material layer; 12. Negative electrode sheet; 1201. Second current collector; 1202. Second active material layer; 13. Separator;

[0027] 2. Current collecting parts;

[0028] 3. non-coating portion; 31. first base film layer; 32. first metal layer; 3001. connection surface;

[0029] 4. coating part; 41. second base film layer; 42. second metal layer;

[0030] 5. adapter; 51. first adapter surface;

[0031] 61. a first foil substrate; 62. a second foil substrate;

[0032] 71. A third foil substrate; 72. A pole ear sleeve; 73. A fourth foil substrate. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0034] Embodiment 1

[0035] Reference Figure 1 to Figure 5 As shown, the first embodiment of the utility model provides a battery cell, which includes a battery cell body 1, and the battery cell body 1 includes a positive electrode sheet 11, a negative electrode sheet 12 and a separator 13 for separating the positive electrode sheet 11 and the negative electrode sheet 12; in the thickness direction, the positive electrode sheet 11 includes a first current collector 1101 and a first active material layer 1102, and the first active material layer 1102 is set as a positive electrode active material, which is coated on a partial area of ​​the surface of the first current collector 1101; in the thickness direction, the negative electrode sheet 12 includes a second current collector 1201 and a second active material layer 1202, and the second active material layer 1202 is set as a negative electrode active material, which is coated on a partial area of ​​the surface of the second current collector 1201. The first current collector 1101 and the second current collector 1201 are both current collectors 2. In the direction in which the current collector 2 extends, the current collector 2 includes a non-coating portion 3 and a coating portion 4. The portion of the current collector 2 used to coat the positive electrode active material or the negative electrode active material is set as the coating portion 4, and the portion other than the coating portion 4 is set as the non-coating portion 3. The non-coating portion 3 serves as a pole ear to achieve electrical connection between the battery cell body 1 and the connecting sheet. The battery cell described in Example 1 of the utility model improves the structural strength of the pole ear by thickening the non-coating portion 3 to avoid damage during the flattening process and affect the product yield.

[0036] Specifically, refer to Figure 1 As shown, the coated portion 4 extends along a first direction, and the non-coated portion 3 is arranged on one side of the coated portion 4 in the first direction; in the first direction, one end of the non-coated portion 3 is connected to the coated portion 4, and the other end surface of the non-coated portion 3 serves as a connecting surface 3001 for bonding and connecting with the adapter plate 5.

[0037] Next, the thickness direction of the coating portion 4 and the non-coating portion 3 is set to a second direction, and the second direction is perpendicular to the first direction. The thickness of the non-coating portion 3 is H1, the thickness of the coating portion 4 is H2, and H2

[0038] Further, refer to Figure 5 ​As shown, the thickness of the first active material layer 1102 in the second direction is a, and the first active material layer 1102 is coated on the two side surfaces of the second direction of the coating portion 4 of the first current collector; in some embodiments, the positive electrode sheet 11 satisfies H2+2a

[0039] In addition, the inventors of this case have discovered through research that in the prior art, since the coating portion 4 of the current collector 2 is coated with active material, there is a thickness difference between the coating portion 4 and the non-coating portion 3 in the second direction. Especially in the high energy density battery solution, the active material determines the battery output capacity and energy density. In the thick electrode solution involved, the thickness difference between the coating portion 4 and the non-coating portion 3 reaches the millimeter level, resulting in a gap between the tabs in the second direction and making it difficult for them to fit together. During welding, welding defects such as cold welds or exploded spots are prone to occur, resulting in insufficient welding tension, increased conductive internal resistance and overcurrent temperature rise. In the first embodiment of the present invention, H2 is set to be less than H1, and the gap size in the second direction when the pole ears are fitted together is reduced by increasing the thickness of the non-coated portion 3, thereby improving the welding quality to a certain extent; preferably, H2+2a

[0040] Specifically, refer to Figure 6 As shown, the first direction is the height direction of the battery cell body 1, and the second direction is the thickness direction of the battery cell body 1; in the first embodiment of the utility model, the battery cell body 1 is set as a wound battery cell, and the positive electrode sheet 11, the separator 13 and the negative electrode sheet 12 are stacked and wound to form the battery cell body 1, wherein the non-coating portion 3 is arranged in plurality along the winding direction of the wound battery cell. The positive electrode sheet 11 includes a plurality of the non-coating portions 3, and the non-coating portions 3 of the positive electrode sheet 11 extend along the first direction and are stacked in sequence along the second direction to form a positive electrode ear group; the negative electrode sheet 12 includes a plurality of the non-coating portions 3, and the non-coating portions 3 of the negative electrode sheet 12 extend along the first direction and are stacked in sequence along the second direction to form a negative electrode ear group, and the negative electrode ear group is located on the opposite side of the positive electrode ear group in the first direction.​​

[0041] Further, refer to Figure 4 and Figure 5 As shown, taking the non-coated portion 3 on one side in the first direction as an example; the thickness of the diaphragm 13 is c, then H1≤2a+2b+2c+2H2; when H1=2a+2b+2c+2H2, the non-coated portions 3 of the two adjacently arranged pole pieces with the same polarity abut against each other in the second direction without overlapping areas, at which time the area of ​​the connecting surface 3001 is the largest, and the area used for welding with the connecting piece is the largest. In the first embodiment of the utility model, preferably, H1 satisfies,

[0042] H2+2a

[0043] H2+2b

[0044] In some embodiments, a=40 μm, b=10 μm, c=50 μm; in some embodiments, 4 μm≤H2≤15 μm and is preferably set to 10 μm, and H1 is preferably set to 50 μm.

[0045] Specifically, refer to Figure 1 As shown, the length of the non-coating portion 3 in the first direction is d1, 10mm≤d1≤50mm, and is preferably set to 40mm; the length of the coating portion 4 in the first direction is d2, 100mm≤d2≤500mm, and is preferably set to 180mm.

[0046] Specifically, refer to Figure 1 to Figure 3 As shown, the current collector 2 is configured as a composite structure, the non-coating portion 3 includes a first base film layer 31 and two first metal layers 32, the two first metal layers 32 are respectively arranged on both sides of the thickness direction of the first base film layer 31; the coating portion 4 includes a second base film layer 41 and two second metal layers 42, the two second metal layers 42 are respectively arranged on both sides of the thickness direction of the second base film layer 41. The first base film layer 31 and the second base film layer 41 are connected as a whole, the thickness of the first base film layer 31 is the same as the thickness of the second base film layer 41, and both are set to H3; H3 satisfies 1μm≤H3≤5μm, and is preferably set to 2μm; the first metal layer 32 and the second metal layer 42 are connected as a whole, and the thickness of the first metal layer 32 is greater than the thickness of the second metal layer 42, so as to achieve the thickening of the non-coating portion 3.

[0047] ​​Furthermore, the first base film layer 31 and the second base film layer 41 are both configured as PET filling layers. When the battery cell body 1 thermally runs away, the filling materials in the first base film layer 31 and the second base film layer 41 can expand due to heat, thereby destroying the structure of the current collector 2 and further destroying the connection between the pole ears, thereby alleviating the risk of thermal runaway.

[0048] Next, the PET filling layer includes graphene and fire-fighting medium; the thermal conductivity of the graphene is 5300W / (m*K), while the thermal conductivity of copper is 401W / (m*K), and the thermal conductivity of aluminum is 237W / (m*K). The thermal conductivity of graphene is much larger than that of copper and aluminum. When copper or aluminum is used as the electrode metal layer material, the graphene in the coated active material layer can quickly dissipate heat and reduce the temperature rise at the connection between the electrode ear and the electrode.

[0049] Next, the firefighting medium is set as a heat-expanding material, and in some embodiments, specifically includes a carbon fiber and resin composite material, fire mud, and a foaming agent such as melamine; when the battery body 1 is in thermal runaway, the firefighting medium can expand, increase the thickness in the second direction, and then create a gap between the tabs, disconnect the tabs from the connecting piece, and solve the safety problem caused by continuous temperature rise under thermal runaway. The deformation temperature T of the PET filling layer is ≥100°C, and the deformation amount S satisfies 100%≤S≤300% after the temperature continues to rise to the deformation temperature, destroying the connection structure.

[0050] In some embodiments, reference Figure 2 As shown, the non-coating portion 3 is a first foil substrate 61, and the coating portion 4 is a second foil substrate 62, and the first foil substrate 61 and the second foil substrate 62 are connected as a whole. The non-coating portion 3 is thickened by controlling the foil calendering time, and the non-coating portion 3 and the coating portion 4 are an integrated structure.

[0051] In some embodiments, reference Figure 3 As shown, the non-coated portion 3 includes a third foil substrate 71 and a pole ear sleeve 72, and the coated portion 4 is a fourth foil substrate 73, and the third foil substrate 71 and the fourth foil substrate 73 are connected as a whole, wherein the thickness of the third foil substrate 71 is equal to the thickness of the fourth foil substrate 73; the pole ear sleeve 72 is sleeved on the outside of the third foil substrate 71, and the first metal layer 32 is thickened by sleeved on the pole ear sleeve 72; the pole ear sleeve 72 is set to a metal material consistent with the surface of the third foil substrate 71.

[0052] Embodiment 2

[0053] The difference between the second embodiment of the utility model and the first embodiment is that the battery body 1 is a laminated battery, the positive electrode sheet 11, the separator 13 and the negative electrode sheet 12 are arranged in sequence along the second direction as a group, and multiple groups of the positive electrode sheet 11, the separator 13 and the negative electrode sheet 12 are stacked in the battery body 1. Therefore, a plurality of current collectors 2 are arranged in the second direction in the battery body 1, and the second direction is the thickness direction of the battery body 1. The non-coating parts 3 of the plurality of current collectors 2 are stacked in sequence along the second direction, and the non-coating parts 3 are thickened by pressing the tabs or sleeved with the tab sleeves 72, thereby increasing the area of ​​the connection surface 3001, improving the electrical connection strength between the tabs and the connection sheets, and improving the current capacity.

[0054] Embodiment 3

[0055] Embodiment 3 of the present invention provides a battery, which includes a transfer sheet 5 and the battery cell described in embodiment 1 or embodiment 2, wherein the transfer sheet 5 includes a first transfer surface 51 which is perpendicular to the first direction, and the first transfer surface 51 and the connection surface 3001 of the non-coating portion 3 are adhered and connected; the non-coating portion 3 is thickened to make the area of ​​the connection surface 3001 larger, the area in contact with the first transfer surface 51 is larger, and the current-carrying capacity is stronger.

[0056] Specifically in this embodiment, two adapter plates 5 are provided, and the polarities of the two adapter plates are opposite.

[0057] Embodiment 4

[0058] A fourth embodiment of the present invention provides an electrical device, which includes the battery described in the third embodiment.

[0059] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. A battery cell, characterized in that: Including the battery body, The battery cell body (1) comprises a positive electrode sheet (11), a negative electrode sheet (12) and a separator (13) used to separate the positive electrode sheet (11) and the negative electrode sheet (12); the positive electrode sheet (11) comprises a first current collector (1101) and a first active material layer (1102); the negative electrode sheet (12) comprises a second current collector (1201) and a second active material layer (1202); the first current collector (1101) and the second current collector (1201) are both current collectors (2); The current collector (2) comprises a non-coating portion (3) and a coating portion (4), the thickness of the non-coating portion (3) is H1, the thickness of the coating portion (4) is H2, and the following conditions are satisfied: H2<H1; the coating portion (4) extends along a first direction; the non-coating portion (3) is arranged on one side of the coating portion (4) in the first direction; in the first direction, one end of the non-coating portion (3) is connected to the coating portion (4); the other end face of the non-coating portion (3) is a connection face (3001) for bonding and connecting with a transfer sheet (5); wherein the first direction is the height direction of the battery cell body (1).

2. The battery cell according to claim 1, characterized in that: The thickness of the first active material layer (1102) is a, the thickness of the second active material layer (1202) is b, and the thickness of the separator (13) is c, satisfying H1≤2a+2b+2c+2H2.

3. The battery cell according to claim 1, characterized in that: The length of the non-coating portion (3) in the first direction is d1, 10 mm ≤ d1 ≤ 50 mm; the length of the coating portion (4) in the first direction is d2, 100 mm ≤ d2 ≤ 500 mm.

4. The battery cell according to claim 1, characterized in that: The battery cell body (1) is a wound battery cell, and a plurality of the non-coating parts (3) are provided. The plurality of non-coating parts (3) are stacked in sequence along a second direction, and the second direction is the thickness direction of the battery cell body (1).

5. The battery cell according to claim 1, characterized in that: The battery cell body (1) is a laminated battery cell, a plurality of current collectors (2) are provided, and the non-coated portions (3) of the plurality of current collectors (2) are stacked in sequence along a second direction, wherein the second direction is a thickness direction of the battery cell body (1).

6. The battery cell according to any one of claims 1 to 5, characterized in that: The non-coating portion (3) comprises a first base film layer (31) and two first metal layers (32), wherein the two first metal layers (32) are respectively arranged on both sides of the thickness direction of the first base film layer (31); the coating portion (4) comprises a second base film layer (41) and two second metal layers (42), wherein the two second metal layers (42) are respectively arranged on both sides of the thickness direction of the second base film layer (41); the first base film layer (31) and the second base film layer (41) are connected as a whole; the first metal layer (32) and the second metal layer (42) are connected as a whole, wherein the thickness of the first base film layer (31) is the same as the thickness of the second base film layer (41), and the thickness of the first metal layer (32) is greater than the thickness of the second metal layer (42).

7. The battery cell according to any one of claims 1 to 5, characterized in that: The non-coated portion (3) is a first foil substrate (61), and the coated portion (4) is a second foil substrate (62). The first foil substrate (61) and the second foil substrate (62) are connected as one body.

8. The battery cell according to any one of claims 1 to 5, characterized in that: The non-coated portion (3) comprises a third foil substrate (71) and a pole lug sleeve (72); the coated portion (4) is a fourth foil substrate (73); the third foil substrate (71) and the fourth foil substrate (73) are connected as a whole, wherein the thickness of the third foil substrate (71) is equal to the thickness of the fourth foil substrate (73); and the pole lug sleeve (72) is sleeved outside the third foil substrate (71).

9. A battery, characterized in that: The invention comprises a transfer sheet (5) and a battery cell according to any one of claims 1 to 8, wherein the transfer sheet (5) comprises a first transfer surface (51) perpendicular to the first direction, and the first transfer surface (51) and a connecting surface (3001) of the non-coated portion (3) are attached and connected.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 9.

Images