Electrode plate integral structure, battery comprising electrode plate integral structure and manufacturing process of electrode plate integral structure

Abstract

The invention discloses an electrode plate overall structure, a battery comprising the same and a manufacturing process, and belongs to the technical field of batteries, the electrode plate overall structure comprises an electrode plate and a diaphragm, the electrode plate comprises a current collector, a solid bottom coating arranged on the current collector and an active coating arranged on the solid bottom coating, the length of the solid bottom coating is larger than that of the active coating, and the diaphragm is arranged on the active coating. And the solid bottom coating and part of the active coating at the head of the electrode plate and the diaphragm form a thermal composite structure. The length of the solid bottom coating at the head of the negative plate of the lithium battery is prolonged, and the negative plate positioned on the inner ring of the battery cell and the diaphragm are thermally compounded to form a thermal composite structure, so that the solid bottom coating at the head of the negative plate, a part of active coating and the diaphragm generate strong bonding force, and the problem of core pulling after winding is finished can be reduced; meanwhile, the cell flatness is improved, and the lithium precipitation hidden danger is reduced.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and more specifically, relates to an integral structure of an electrode sheet, a battery containing the electrode sheet, and a manufacturing process thereof. Background Technology

[0002] In battery manufacturing, winding equipment is used to wind electrodes and separators into battery cells. The initial winding step involves pre-winding a certain number of layers of separator with the winding needles. Then, the electrodes are fed to the winding needles, and finally, the electrodes and separators are wound together to form the battery cell. After winding and pre-pressing, the battery cell has a flat structure. However, during the needle extraction process, the inner separator, due to looseness, is easily pulled out along with the needles, resulting in an uneven inner ring of the battery cell. This can easily lead to lithium plating during use, affecting the safety of the battery cell. Summary of the Invention

[0003] To solve the above problems, the present invention adopts the following technical solution:

[0004] An integral electrode sheet structure includes an electrode sheet and a diaphragm. The electrode sheet includes a current collector, a solid base coating disposed on the current collector, and an active coating disposed on the solid base coating. The length of the solid base coating is greater than the length of the active coating. The solid base coating and part of the active coating at the head of the electrode sheet form a thermal composite structure with the diaphragm.

[0005] Furthermore, the current collector includes an empty foil area, a first region, and a second region connected in sequence, wherein the empty foil area is located at the head of the electrode sheet, the solid undercoating is disposed in the first region and the second region, and the active coating is disposed in the second region.

[0006] Furthermore, a solid undercoat layer is applied to both the upper and lower surfaces of the current collector.

[0007] Furthermore, the length of the empty foil area is L1, where 0.5mm ≤ L1 ≤ 15mm.

[0008] Furthermore, the length of the first region is L2, where 2mm ≤ L2 ≤ 15mm.

[0009] Furthermore, the thermal composite structure is formed by hot pressing a solid undercoat layer located in the first region, an active coating layer partially located in the second region, and the diaphragm. The active coating layer partially located in the second region is connected to the solid undercoat layer in the first region, and the length of the active coating layer partially located in the second region is L3, where 2mm < L3 < 100mm.

[0010] Furthermore, the solid undercoat includes one or more of graphene, carbon black, carbon fiber, graphite, and carbon nanotubes.

[0011] Furthermore, the electrode sheet is a positive and / or negative electrode sheet.

[0012] A battery that employs the integral electrode sheet structure described in any of the above-mentioned embodiments.

[0013] A battery manufacturing process, which is the battery manufacturing process described above, includes the following steps:

[0014] The manufacturing process includes the following steps:

[0015] S1. Apply a solid primer coating to both sides of the positive and / or negative current collector;

[0016] S2. Apply the active layer slurry onto the solid base layer, making the length of the solid base layer 2-15 mm longer than the length of the active layer, then bake and roll it up.

[0017] S3. Cold press, slit and wind up the electrode sheets;

[0018] S4. The positive electrode, negative electrode and separator are sent to the winding machine. The solid bottom coating and part of the active coating of the positive electrode head are combined with the separator, and the solid bottom coating and part of the active coating of the negative electrode head are combined with the separator. The two are then wound to obtain the bare cell.

[0019] Alternatively, the solid undercoat and part of the active coating on the electrode head of the positive electrode sheet are combined with the separator on a winding machine to form a positive electrode thermal composite structure, which is then wound with the negative electrode sheet and the separator to obtain a bare cell.

[0020] Alternatively, the solid undercoat and part of the active coating on the electrode head of the negative electrode sheet are combined with the separator on a winding machine to form a negative electrode thermal composite structure, which is then wound with the separator and the positive electrode sheet to obtain a bare cell.

[0021] S5. The bare cells are shaped and charged / discharged to obtain the battery.

[0022] The beneficial effects of this invention are:

[0023] This invention extends the length of the solid undercoat at the head of the lithium battery negative electrode and thermally composites the portion of the negative electrode located in the inner ring of the cell with the separator to form a thermal composite structure. This creates a strong adhesion between the solid undercoat, part of the active coating, and the separator at the head of the negative electrode, which can reduce the problem of core pulling after winding and improve the flatness of the cell, thereby reducing the risk of lithium plating. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the electrode sheet negative electrode coating structure of the present invention;

[0025] Figure 2 This is a schematic planar view of the inner ring structure of the battery cell after thermal bonding according to the present invention.

[0026] In the figure: 1. Current collector; 101. Solid base coating of the first region; 2. Negative electrode; 3. Separator; 4. Positive electrode. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] Example 1

[0029] refer to Figures 1 to 2 An integral electrode sheet structure includes an electrode sheet and a separator 3. The electrode sheet includes a current collector 1, a solid undercoat layer disposed on the current collector 1, and an active coating layer disposed on the solid undercoat layer. The length of the solid undercoat layer is greater than the length of the active coating layer. By hot pressing, the solid undercoat layer and part of the active coating layer at the head of the electrode sheet located in the inner ring of the battery cell form a thermal composite structure with the separator 3.

[0030] This invention extends the length of the solid undercoat at the head of the lithium battery negative electrode 2 and thermally composites the negative electrode 2 located in the inner ring of the cell with the separator 3 to form a thermal composite structure. This results in strong adhesion between the solid undercoat, part of the active coating, and the separator 3 at the head of the negative electrode 2, which can reduce the problem of core pulling after winding and improve the flatness of the cell, thereby reducing the risk of lithium plating.

[0031] In practice, the head of the electrode sheet refers to the part of the electrode sheet located in the inner ring of the battery cell after it has been wound.

[0032] In this embodiment, the current collector 1 includes an empty foil area, a first area, and a second area connected in sequence, wherein a solid undercoating is disposed in the first area and the second area, and an active coating is disposed in the second area.

[0033] In this embodiment, the empty foil area is located at the head of the electrode sheet.

[0034] In this embodiment, a solid undercoat layer is disposed on the upper and lower surfaces of the current collector 1.

[0035] In this embodiment, the length of the empty foil area located at the electrode head is L1, 0.5mm≤L1≤15mm.

[0036] In this embodiment, the length of the first region is L2, where 2mm ≤ L2 ≤ 15mm.

[0037] In this embodiment, the thermal composite structure is formed by hot pressing a solid base coating 101 located in the first region, a solid base coating partially located in the second region, an active coating, and a diaphragm 3. The active coating partially located in the second region is connected to the solid base coating in the first region, and the length of the active coating partially located in the second region is L3, where 2mm < L3 < 100mm.

[0038] In this embodiment, the solid undercoat includes one or more of graphene, carbon black, carbon fiber, graphite, and carbon nanotubes.

[0039] In this embodiment, the electrode sheet is a positive and / or negative electrode sheet 2.

[0040] Example 2

[0041] This embodiment provides a battery, including the overall electrode sheet structure of Embodiment 1.

[0042] Example 3

[0043] This embodiment provides a battery manufacturing process, which is the battery manufacturing process of Embodiment 2, and its steps include:

[0044] S1. Apply a solid primer coating to both sides of the positive and / or negative current collector;

[0045] S2. Apply the active layer slurry onto the solid base layer, making the length of the solid base layer 2-15 mm longer than the length of the active layer, then bake and roll it up.

[0046] S3. Cold press, slit and wind up the electrode sheets;

[0047] S4. Bare battery cells can be prepared using the following three methods;

[0048] The first method involves sending the positive electrode, negative electrode, and separator to a winding machine, where the solid undercoating and part of the active coating on the electrode head of the positive electrode are combined with the separator, and the solid undercoating and part of the active coating on the electrode head of the negative electrode are combined with the separator. The two are then wound together to obtain a bare battery cell.

[0049] The second method involves forming a positive electrode thermal composite structure by combining the solid undercoating and part of the active coating on the electrode head of the positive electrode sheet with the separator on a winding machine, and then winding it with the negative electrode sheet and separator to obtain a bare cell.

[0050] The third method: The solid bottom coating and part of the active coating of the negative electrode sheet are combined with the separator on a winding machine to form a negative electrode thermal composite structure, and then wound with the separator and positive electrode sheet to obtain a bare cell.

[0051] S5. The bare cells are shaped and charged / discharged to obtain the battery.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An integral electrode sheet structure, characterized in that, The device includes an electrode sheet and a diaphragm. The electrode sheet includes a current collector, a solid base coating disposed on the current collector, and an active coating disposed on the solid base coating. The length of the solid base coating is greater than the length of the active coating. The solid base coating and part of the active coating at the head of the electrode sheet form a thermal composite structure with the diaphragm.

2. The integral electrode sheet structure according to claim 1, characterized in that, The current collector includes an empty foil area, a first region, and a second region connected in sequence, wherein the empty foil area is located at the head of the electrode sheet, the solid undercoating is disposed in the first region and the second region, and the active coating is disposed in the second region.

3. The integral electrode sheet structure according to claim 1, characterized in that, The solid base coating is applied to both the top and bottom surfaces of the current collector.

4. The integral electrode sheet structure according to claim 2, characterized in that, The length of the empty foil area is L1, where 0.5mm ≤ L1 ≤ 15mm.

5. The integral electrode sheet structure according to claim 2, characterized in that, The length of the first region is L2, where 2mm ≤ L2 ≤ 15mm.

6. The integral electrode sheet structure according to claim 2, characterized in that, The thermal composite structure is formed by hot pressing a solid base coating in the first region, an active coating partially located in the second region, and the diaphragm. The active coating partially located in the second region is connected to the solid base coating in the first region, and the length of the active coating partially located in the second region is L3, where 2mm < L3 < 100mm.

7. The integral electrode sheet structure according to claim 1, characterized in that, The solid undercoat includes one or more of graphene, carbon black, carbon fiber, graphite, and carbon nanotubes.

8. The integral electrode sheet structure according to claim 1, characterized in that, The electrode sheet is a positive and / or negative electrode sheet.

9. A battery, characterized in that, The electrode sheet adopts the integral structure described in any one of claims 1-8.

10. A battery manufacturing process, characterized in that, The manufacturing process of the battery according to claim 9 includes the following steps: S1. Apply a solid primer coating to both sides of the positive and / or negative current collector; S2. Apply the active layer slurry onto the solid base layer, making the length of the solid base layer 2-15 mm longer than the length of the active layer, then bake and roll it up. S3. Cold press, slit and wind up the electrode sheets; S4. The positive electrode, negative electrode and separator are sent to the winding machine. The solid bottom coating and part of the active coating of the positive electrode head are combined with the separator, and the solid bottom coating and part of the active coating of the negative electrode head are combined with the separator. The two are then wound to obtain the bare cell. Alternatively, the solid undercoat and part of the active coating on the electrode head of the positive electrode sheet are combined with the separator on a winding machine to form a positive electrode thermal composite structure, which is then wound with the negative electrode sheet and the separator to obtain a bare cell. Alternatively, the solid undercoat and part of the active coating on the electrode head of the negative electrode sheet are combined with the separator on a winding machine to form a negative electrode thermal composite structure, and then wound with the separator and positive electrode sheet to obtain a bare cell. S5. The bare cells are shaped and charged / discharged to obtain the battery.

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