An electrode sheet, an electrode core, an electrode core, and an electric device

Abstract

The utility model relates to a battery field especially relates to a kind of pole piece, pole core, battery and electric equipment, including the active material layer is arranged in the thickness direction of the current collector one side, the bending resistance layer is arranged in the thickness direction of the current collector other side;The bending resistance layer and the material of the active material layer are different, the thickness of the current collector is a, the thickness of the bending resistance layer is b, the thickness of the active material layer is c, due to the existence of bending resistance layer, when pole piece is rolled, stress exists in the thickness direction of the current collector both sides, so that the thickness direction of the current collector both sides is stressed evenly, to ensure that the current collector is in stress equilibrium state, reduce the bending or curling phenomenon caused by uneven stress.

Description

Technical Field

[0001] This utility model belongs to the field of batteries, and in particular relates to an electrode sheet, an electrode core, a battery cell, and an electrical device. Background Technology

[0002] A battery stack is composed of alternating layers of key materials such as positive electrode sheets, negative electrode sheets, and separators. The positive current collector for the positive electrode sheet is typically made of aluminum foil, while the negative current collector for the negative electrode sheet is typically made of copper foil. To improve the energy density of the battery cell, the outermost layer of the stack is usually a negative electrode sheet formed by a negative current collector coated on one side with negative electrode active material.

[0003] After roll forming, the stress in a negative electrode sheet coated with negative electrode active material on one side can cause the negative electrode current collector to bend or curl towards the side coated with negative electrode active material. Uneven negative electrode sheets can affect the subsequent stacking positioning and coverage accuracy, and in severe cases, can affect the safety performance of the battery cell. Therefore, there is an urgent need for a negative electrode sheet that can reduce the occurrence of bending. Summary of the Invention

[0004] The technical problem to be solved by this utility model is: to address the issue that existing negative electrode sheets coated with negative electrode active material on one side are prone to bending during rolling, which affects battery quality, and to provide an electrode sheet, electrode core, battery cell, and electrical equipment.

[0005] To address the aforementioned problems, one embodiment of this utility model provides an electrode sheet comprising a current collector, an active material layer, and a bending-resistant layer;

[0006] The active material layer is disposed on one side of the current collector in the thickness direction, and the bending-resistant layer is disposed on the other side of the current collector in the thickness direction.

[0007] The bending-resistant layer and the active material layer are made of different materials. The current collector has a thickness of 'a', the bending-resistant layer has a thickness of 'b', and the active material layer has a thickness of 'c'. , .

[0008] Optionally, the bending-resistant layer is a ceramic layer.

[0009] Optionally, the bending-resistant layer is a polymer material layer.

[0010] Optionally, the polymer material layer is one of a PET layer, a PVDF layer, a PI layer, and a PDA layer.

[0011] Optionally, a is 3-20 b is 8-30 c is 30-100 .

[0012] Optionally, the elastic modulus of the bending-resistant layer is 1-10 GPa; the molecular weight of the bending-resistant layer is 5-2 million.

[0013] On the other hand, this utility model embodiment also provides an electrode core, including an electrode core body and the aforementioned electrode sheet;

[0014] The electrode core body is formed by alternatingly stacking a positive electrode sheet, a separator, and a negative electrode sheet along a first direction. The separator is located on both sides of the electrode core body along the first direction. The electrode sheet is stacked on at least one side of the electrode core body along the first direction, and the active material layer of the electrode sheet is attached to the electrode core body.

[0015] Optionally, the electrode sheets are stacked on both sides of the electrode core body along the first direction.

[0016] In another aspect, this utility model embodiment also provides a battery cell, including a housing and the aforementioned electrode core, wherein the electrode core is disposed within the housing.

[0017] Furthermore, this utility model embodiment also provides an electrical device, including the aforementioned battery cell.

[0018] The present invention provides an electrode sheet, electrode core, battery cell, and electrical device. Due to the presence of the bending-resistant layer, stress exists on both sides of the current collector in the thickness direction during the rolling of the electrode sheet. This ensures that the current collector is subjected to uniform force on both sides in the thickness direction, thereby ensuring that the current collector is in a stress balance state and reducing bending or rolling phenomena caused by uneven stress. As a result, when the electrode sheet is applied to the stacked core, the flatness of the electrode sheet does not interfere with the subsequent stacking positioning and covering accuracy, thus stabilizing the safety performance of the battery cell. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is an overall schematic diagram of the electrode sheet provided in one embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the overall structure of the electrode core provided in one embodiment of the present invention.

[0022] The reference numerals in the accompanying drawings are as follows:

[0023] 1. Electrode; 11. Current collector; 12. Active material layer; 13. Bending layer; 2. Negative electrode; 3. Positive electrode; 4. Separator. Detailed Implementation

[0024] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0025] In the description of this utility model, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0026] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] like Figure 1 and Figure 2 As shown, one embodiment of this utility model provides an electrode 1, including a current collector 11, an active material layer 12, and a bending-resistant layer 13; the active material layer 12 is disposed on one side of the current collector 11 in the thickness direction, and the bending-resistant layer 13 is disposed on the other side of the current collector 11 in the thickness direction; the bending-resistant layer 13 and the active material layer 12 are made of different materials, the thickness of the current collector 11 is a, the thickness of the bending-resistant layer 13 is b, and the thickness of the active material layer 12 is c. , .

[0028] In this embodiment, due to the presence of the bending-resistant layer 13, stress exists on both sides of the current collector 11 in the thickness direction when the electrode sheet 1 is rolled, so that the current collector 11 is subjected to uniform force on both sides in the thickness direction, ensuring that the current collector 11 is in a stress balance state, reducing bending or rolling phenomena caused by uneven stress. Thus, when the electrode sheet 1 is applied to the stacked core, the flatness of the electrode sheet 1 does not interfere with the subsequent stacking positioning and covering accuracy, thereby stabilizing the safety performance of the battery cell.

[0029] Moreover, compared to the foil of the electrode 1 with a single-sided active material layer 12 in the prior art, which is prone to burrs during the die-cutting process, the current collector 11 of the electrode 1 in this embodiment is less prone to burrs during the die-cutting process, thereby reducing the probability of burrs puncturing the diaphragm 4 and causing a short circuit.

[0030] Furthermore, since the thicknesses of the current collector 11, the bending layer 13, and the active material layer 12 follow the above relationship, it can ensure that the thickness of the electrode 1 is reasonably distributed, avoiding any one of the three being too thick, occupying too much volume of the electrode 1, and affecting the energy density of the electrode 1, thereby making the stacked core volume reasonable and the energy density high.

[0031] In this embodiment, the current collector 11 is a copper foil, and the electrode 1 is a negative electrode.

[0032] In other embodiments, the current collector 11 is an aluminum foil, and the electrode 1 is a positive electrode.

[0033] In one embodiment, the bending-resistant layer 13 is a ceramic layer.

[0034] In one embodiment, the bending-resistant layer 13 is a polymer material layer. Specifically, the polymer material layer is one of a PET layer, a PVDF layer, a PI layer, and a PDA layer. Any of the above-mentioned polymer material layers can increase the surface tension of the current collector 11 on its side. Furthermore, due to the entanglement of the polymer materials forming a network structure and mutual cross-linking, the bonding force between the entangled network of polymer materials and the current collector 11 needs to be overcome before the electrode 1 bends, thus preventing bending and curling phenomena from occurring.

[0035] In one embodiment, a is 3-20 μm, b is 8-30 μm, and c is 30-100 μm. In this embodiment, the thicknesses of the current collector 11, the bending layer 13, and the active material layer 12 are generally controlled within the above-mentioned ranges. These ranges can be applied to most common specifications of stacked cores, and the thicknesses of the current collector 11 and the active material layer 12 can limit the thickness of the electrode 1.

[0036] In one embodiment, the elastic modulus of the bending-resistant layer 13 is 1-10 GPa; the molecular weight of the bending-resistant layer 13 is 5-2 million. The elastic modulus and molecular weight of the bending-resistant layer 13 as described above can ensure that the electrode 1 does not curl.

[0037] In addition, this utility model embodiment also provides an electrode core, including an electrode core body and the aforementioned electrode sheet 1. The electrode core body is formed by alternatingly stacking a positive electrode sheet 3, a separator 4, and a negative electrode sheet 2 along a first direction. The separator 4 is located on both sides of the electrode core body along the first direction. The electrode sheet 1 is stacked on at least one side of the electrode core body along the first direction, and the active material layer 12 of the electrode sheet 1 is attached to the electrode core body.

[0038] Similar to common stacked cores, the core body is formed by alternating layers of positive electrode plate 3, negative electrode plate 2 and separator 4. The separator 4 is used to isolate the electrode plate 1 on the outermost side of the core body along the first direction. That is, the positive electrode plate 3 is on the second outermost side of the core body, and the positive electrode plate 3 and the electrode plate 1 are separated by the outermost separator 4.

[0039] In this embodiment, the outermost part of the core body is a positive electrode 3. Therefore, the electrode 1 is stacked on both sides of the core body along the first direction. A diaphragm is provided on the side of the electrode 1 away from the core body to isolate and protect the electrode 1.

[0040] In addition, one embodiment of the present invention provides a battery cell, including a housing and the aforementioned electrode core, wherein the electrode core is disposed within the housing.

[0041] In addition, one embodiment of this utility model also provides an electrical device, including the battery cell described in the above embodiment.

[0042] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. An electrode sheet, characterized in that, Includes current collector, active material layer and bending resistance layer; The active material layer is disposed on one side of the current collector in the thickness direction, and the bending-resistant layer is disposed on the other side of the current collector in the thickness direction. The bending-resistant layer and the active material layer are made of different materials. The current collector has a thickness of 'a', the bending-resistant layer has a thickness of 'b', and the active material layer has a thickness of 'c'. , .

2. The electrode sheet according to claim 1, characterized in that, The bending-resistant layer is a ceramic layer.

3. The electrode sheet according to claim 1, characterized in that, The bending-resistant layer is a polymer material layer.

4. The electrode sheet according to claim 3, characterized in that, The polymer material layer is one of PET layer, PVDF layer, PI layer and PDA layer.

5. The electrode sheet according to claim 3, characterized in that, a is 3-20 b is 8-30 c is 30-100 .

6. The electrode sheet according to claim 3, characterized in that, The elastic modulus of the bending-resistant layer is 1-10 GPa; the molecular weight of the bending-resistant layer is 5-2 million.

7. A polar core, characterized in that, Includes the electrode core body and the electrode sheet according to any one of claims 1-6; The electrode core body is formed by alternatingly stacking a positive electrode sheet, a separator, and a negative electrode sheet along a first direction. The separator is located on both sides of the electrode core body along the first direction. The electrode sheet is stacked on at least one side of the electrode core body along the first direction, and the active material layer of the electrode sheet is attached to the electrode core body.

8. The electrode core according to claim 7, characterized in that, The electrode sheets are stacked on both sides of the electrode core body along the first direction.

9. A battery cell, characterized in that, It includes a housing and the electrode core as described in claim 7 or 8, wherein the electrode core is disposed within the housing.

10. An electrical appliance, characterized in that, Includes the battery cell described in claim 9.

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