A pole piece structure

Abstract

This invention provides an electrode structure comprising a current collector, an active material layer, and a flow channel. At least one through-flow channel is formed on either side of the electrode. The flow channel consists of a functional coating and a flow channel above the coating. The functional coating is selected from one or more of ceramic coatings, solid electrolyte coatings, and polymer coatings. This invention coats the flow channel with a functional coating. The functional coating has better hydrophilicity than the active material, resulting in better liquid absorption and retention capabilities, higher cell wetting efficiency, and better wetting effect. This alleviates the problem of electrolyte deficiency in the middle area of ​​the cell and helps extend the cell's cycle life.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion batteries, and in particular to an electrode structure. Background Technology

[0002] With the rapid development of the new energy industry, the application scenarios of lithium-ion battery cells are becoming increasingly widespread, and the market demand for large-capacity lithium-ion battery cells is growing. However, during the production process of large-size, high-capacity battery cells, the central area of ​​the electrode sheet suffers from low wetting efficiency and poor wetting effect. During battery cycling, black spots and lithium plating may appear in the central area of ​​the electrode sheet, significantly affecting the cycle life of the battery cell.

[0003] Chinese patent CN117995981A discloses an electrode structure; the electrode structure includes a negative electrode and a negative electrode tab disposed on the negative electrode, wherein the negative electrode has lithium ion flow channels of arbitrary shape, and the lithium ion flow channels are channels that are equidistant in the longitudinal and transverse directions.

[0004] In the aforementioned patent, the lithium-ion flow channel is opened on the active material, and the electrolyte is in direct contact with the active material or foil. The active material or foil has weak hydrophilicity, liquid absorption and liquid retention capacity, resulting in low cell wetting efficiency and poor wetting effect. After long-term cycling, the middle area of ​​the cell lacks electrolyte, which will cause black spots and lithium plating problems, affecting cycle life.

[0005] To address this issue, we propose an electrode structure to solve the problem of poor wetting effect. Utility Model Content

[0006] The purpose of this utility model is to overcome the shortcomings of the existing technology. To achieve the above objective, this utility model adopts the following technical solution:

[0007] An electrode structure is provided, comprising a current collector, an active material layer, and a flow channel. At least one through-flow channel is provided on the front and back sides of the electrode. The flow channel consists of a functional coating and a flow channel above the coating. The electrolyte flow channel with the functional coating can improve the liquid absorption and retention capacity, and the electrolyte diffuses quickly and has good fluidity within the electrolyte flow channel.

[0008] More preferably, the functional coating is selected from one or more of ceramic coatings, solid electrolyte coatings, and polymer coatings.

[0009] More preferably, the width of the flow channel is 0.1~30mm.

[0010] More preferably, the depth of the flow channel is 1~80μm.

[0011] More preferably, the ceramic coating is one of Al2O3 coating, boehmite coating, TiO2 coating, MgO coating, and SiO2 coating.

[0012] More preferably, the solid electrolyte coating is one of LATP coating, LLZO coating, and Li3PS4 coating.

[0013] More preferably, the polymer coating is one of an aramid coating or a polyethylene oxide coating.

[0014] More preferably, one side of the electrode is connected to a tab.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] This invention applies a functional coating to the flow channel. The functional coating has better hydrophilicity than the active material, resulting in better liquid absorption and retention capabilities, higher cell wetting efficiency, and better wetting effect. This alleviates the problem of electrolyte shortage in the middle area of ​​the cell and helps extend the cycle life of the cell. Attached Figure Description

[0017] Figure 1 This is the front view of the present invention;

[0018] Figure 2 This is a side view of the present invention.

[0019] In the diagram: 1. Current collector; 2. Active material layer; 3. Flow channel; 4. Electrode. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0021] Reference Figures 1-2 An electrode structure is provided, comprising a current collector 1 and active material layers 2 respectively disposed on the upper and lower surfaces of the current collector 1. At least one side of the electrode has at least one through-flow groove 3, which consists of a functional coating and a flow channel above the coating. An electrode tab 4 is connected to one side of the electrode. The flow groove 3 contains a functional coating and an upper flow channel. The functional coating is applied to the bottom current collector 1. The electrolyte flow groove with the functional coating can improve the liquid absorption and retention capacity. The electrolyte diffuses quickly and has good fluidity in the electrolyte flow groove.

[0022] In the embodiment: the functional coating can be applied by extrusion coating or transfer coating. Extrusion coating machine is preferred. A functional dressing outlet is designed in the middle of the coating pad. The active material dressing and the functional dressing are coated simultaneously without affecting the coating efficiency. Then, the coating is rolled, slit, and die-cut to obtain the electrolyte flow channel electrode sheet.

[0023] The functional coating is selected from one or more of ceramic coatings, solid electrolyte coatings, and polymer coatings; the functional coating has good liquid absorption and retention capabilities, and the electrolyte diffuses quickly and has good fluidity in the electrolyte flow tank.

[0024] The width of the flow channel 3 is 0.1~30mm, and the depth of the flow channel 3 is 1~80μm.

[0025] In this embodiment: the flow channel runs through the entire electrode and leads to the middle area of ​​the electrode. At least one side of the electrode has an electrolyte flow channel, and there is at least one electrolyte flow channel. The width of the electrolyte flow channel is 10 mm, and the flow channel 3 is 30 μm lower than the active material coating roller thickness, ensuring that the electrolyte flow channel has sufficient space to store and flow the electrolyte. The electrolyte can flow and diffuse laterally within the electrolyte flow channel, and can also diffuse longitudinally into the active material coating area.

[0026] In one embodiment: there is one electrolyte flow channel on each side of the cathode sheet, located in the middle of the electrode sheet, parallel to the cathode sheet and penetrating the electrode sheet, the electrolyte flow channels on the front and back sides are offset by 15mm, the width of the electrolyte flow channel is 5mm, and the thickness is 10μm less than the thickness of the active material coating roller.

[0027] In another embodiment: there is one electrolyte flow channel on each side of the cathode sheet, located in the middle of the electrode sheet, parallel to the cathode sheet and penetrating the electrode sheet, with the electrolyte flow channels on the front and back sides offset by 20mm, the width of the electrolyte flow channel is 10mm, and the thickness is 20μm less than the thickness of the active material coating roller.

[0028] The ceramic coating is one of Al2O3 coating, boehmite coating, TiO2 coating, MgO coating, and SiO2 coating; the ceramic surface has many polar functional groups and has excellent electrolyte wettability.

[0029] In one embodiment: the functional coating is a boehmite ceramic coating, the surface of which contains -OH, which reduces the electrolyte contact angle, resulting in fast electrolyte diffusion and good fluidity.

[0030] The solid electrolyte coating is one of LATP coating, LLZO coating, and Li3PS4 coating; after modification, the solid electrolyte can reduce the surface contact angle and increase the electrolyte wetting effect.

[0031] The polymer coating is one of aramid coating and polyethylene oxide coating; the polymer surface has many polar functional groups and has excellent electrolyte wettability.

[0032] In one embodiment: the functional coating is an aramid coating. After being treated by plasma treatment, chemical modification and other methods, the aramid surface contains -OH and -COOH, which reduces the electrolyte contact angle, and the electrolyte diffusion speed is fast and the fluidity is good.

[0033] This invention applies a functional coating to the inner wall of the flow channel. The functional coating has better hydrophilicity than the active material, resulting in better liquid absorption and retention capabilities, higher cell wetting efficiency, and better wetting effect. This alleviates the problem of electrolyte deficiency in the middle area of ​​the cell and helps extend the cycle life of the cell.

[0034] This invention provides an electrode structure that improves wettability. The electrolyte flow channel leads to the middle area of ​​the electrode, and the electrolyte has good fluidity and fast diffusion ability in the flow channel, which helps the electrode absorb and retain liquid, effectively improving the wetting effect in the middle area of ​​the electrode, thereby improving abnormal problems such as black spots and lithium plating on the electrode. In addition, during the cell manufacturing process, the diffusion distance of the electrolyte in the electrode is shortened, thereby shortening the wetting time and increasing production capacity.

Claims

1. An electrode structure, characterized in that, The electrode is composed of a current collector and active material layers respectively disposed on the upper and lower surfaces of the current collector. At least one of the front and back surfaces of the electrode has one or more through-flow grooves, which are composed of a functional coating and a flow channel above the coating.

2. The electrode structure according to claim 1, characterized in that, The functional coating is selected from one or more of ceramic coatings, solid electrolyte coatings, and polymer coatings.

3. The electrode structure according to claim 2, characterized in that, The width of the flow channel is 0.1~30mm.

4. The electrode structure according to claim 2, characterized in that, The depth of the flow channel is 1~80μm.

5. The electrode structure according to claim 2, characterized in that, The ceramic coating is one of Al2O3 coating, boehmite coating, TiO2 coating, MgO coating, and SiO2 coating.

6. The electrode structure according to claim 2, characterized in that, The solid electrolyte coating is one of LATP coating, LLZO coating, or Li3PS4 coating.

7. The electrode structure according to claim 2, characterized in that, The polymer coating is one of aramid coating and polyethylene oxide coating.

8. The electrode structure according to claim 1, characterized in that, A tab is connected to one side of the electrode.

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