Battery pole piece, battery cell and vehicle

Abstract

The utility model discloses a battery pole piece, a battery cell and a vehicle, the battery pole piece comprises a pole piece body, the surface of the pole piece body is coated with a surface coating to form a composite pole piece, and the surface coating comprises a ceramic material and a phase change material. According to the utility model, the problem of overlarge temperature rise in the charging and discharging process of the battery is effectively solved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of batteries, in particular to a battery pole piece, a battery cell and a vehicle. BACKGROUND

[0002] In order to improve the endurance of new energy vehicles, lithium ion batteries need to have higher energy density and shorter fast charging time, and at the same time, higher energy density and shorter fast charging time put higher requirements on the safety performance of the battery. When the battery is charged at a large current, the heat generated by the battery increases, the temperature of the battery rises rapidly, and the internal side reaction of the battery intensifies, which seriously affects the service life of the battery.

[0003] The existing battery pole piece is obtained by spraying ceramic powder mixed with a binder to the surface of the pole piece, and the ceramic is attached to the surface of the pole piece after the pole piece is heated, and then the pole piece with a ceramic layer can be obtained by rolling. Although the pole piece coated with ceramic can inhibit the expansion of the pole piece, absorb the heat generated by the battery, and reduce the temperature rise of the battery to a certain extent, the effect of absorbing heat and reducing temperature by coating ceramic alone is limited. UTILITY MODEL CONTENT

[0004] The utility model aims at solving the above technical problems and provides a battery pole piece, a battery cell and a vehicle, so as to effectively solve the problem of excessive temperature rise in the charging and discharging process of the battery. In order to achieve the above purpose, the technical scheme of the utility model is as follows:

[0005] The battery pole piece comprises a pole piece body, a surface coating layer is coated on the surface of the pole piece body to form a composite pole piece, and the surface coating layer comprises a ceramic material and a phase change material.

[0006] Specifically, the upper surface and / or the lower surface of the pole piece body is coated with the surface coating layer.

[0007] Specifically, the pole piece body comprises a current collector and an active layer, the upper surface and the lower surface of the current collector are provided with the active layer, and the surface of the active layer away from the current collector is coated with the surface coating layer.

[0008] Specifically, the ceramic material comprises one of boehmite, aluminum oxide, magnesium oxide and titanium dioxide.

[0009] Specifically, the phase change material comprises a microcapsule formed by one of paraffin, fatty acid, fatty alcohol, sugar alcohol, polyethylene glycol and crystalline hydrated salt.

[0010] Specifically, the surface coating layer further comprises a first binder, and the ceramic material, the phase change material and the first binder are in the proportions of 20-30%, 50-60% and 10-30% respectively according to the weight percentage of each component.

[0011] Specifically, the first adhesive comprises one of polyvinylidene fluoride, sodium carboxymethyl cellulose, sodium alginate and butyl rubber latex.

[0012] Specifically, the coating thickness of the surface coating layer is 1-5 microns.

[0013] The battery pole piece or the battery cell comprises the battery pole piece.

[0014] The vehicle comprises the battery pole piece or the battery cell.

[0015] Compared with the prior art, the battery pole piece, the battery cell and the vehicle have the following beneficial effects:

[0016] The ceramic material and the phase change material are mixed and coated on the pole body to form the composite pole piece with the surface coating layer. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The cross-sectional schematic view of the positive composite pole piece is provided for the embodiment of the application.

[0018] Figure 2 The cross-sectional schematic view of the negative composite pole piece is provided for the embodiment of the application.

[0019] Figure 3 The cross-sectional schematic view of the battery cell with the positive composite pole piece is provided for the embodiment of the application.

[0020] Figure 4 The cross-sectional schematic view of the battery cell with the negative composite pole piece is provided for the embodiment of the application.

[0021] Figure 5 The cross-sectional schematic view of the battery cell with the positive composite pole piece and the negative composite pole piece is provided for the embodiment of the application.

[0022] REFERENCE NUMERALS:

[0023] The positive pole piece 1, the positive current collector 11 and the positive active layer 12.

[0024] The negative pole piece 2, the negative current collector 21 and the negative active layer 22.

[0025] The surface coating layer 3,

[0026] The separator 4. DETAILED DESCRIPTION

[0027] In order to make the technical solutions and advantages in the embodiments of the present application clearer, the exemplary embodiments of the present application are further described in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0028] Embodiment one

[0029] The present embodiment provides a battery pole piece, including a pole piece body, and a surface of the pole piece body is coated with a surface coating layer 3 to form a composite pole piece, specifically, the pole piece body is a positive pole piece 1 or a negative pole piece 2, and the composite pole piece is a positive composite pole piece or a negative composite pole piece, as shown in the figure, the surface of the positive pole piece 1 is coated with a surface coating layer 3 to form a positive composite pole piece, and the surface of the negative pole piece 2 is coated with a surface coating layer 3 to form a negative composite pole piece, and the surface coating layer 3 includes a ceramic material, a phase change material, a first binder, and a solvent. Figures 1-2

[0030] The ceramic material includes one of boehmite, aluminum oxide, magnesium oxide, and titanium dioxide. The phase change material includes a microcapsule formed by one of paraffin, fatty acid, fatty alcohol, sugar alcohol, polyethylene glycol, and crystalline hydrated salt. The first binder includes one of polyvinylidene fluoride, sodium carboxymethyl cellulose, sodium alginate, and butyl rubber latex. The solvent can be N-methyl pyrrolidone (NMP).

[0031] The ceramic material, the phase change material, and the first binder have proportions of 20-30%, 50-60%, and 10-30% respectively in terms of weight percentage.

[0032] The upper surface and / or the lower surface of the pole piece body are coated with the surface coating layer 3, specifically, the upper surface and / or the lower surface of the positive pole piece 1 are coated with the surface coating layer 3, and the upper surface and / or the lower surface of the negative pole piece 2 are coated with the surface coating layer 3.

[0033] The pole piece body includes a current collector and an active layer, specifically, the positive pole piece 1 includes a positive current collector 11 and a positive active layer 12, the upper surface and the lower surface of the positive current collector 11 are provided with the positive active layer 12, and the surface of the positive active layer 12 away from the positive current collector 11 is coated with the surface coating layer 3.

[0034] ​The positive electrode current collector 11 can be an aluminum foil. The positive electrode active layer 12 includes a positive electrode active material, a positive electrode conductive agent, and a second binder. The positive electrode active material includes lithium nickel cobalt manganese oxide (NCM) or lithium iron phosphate (LFP), and the positive electrode conductive agent includes one of conductive carbon black of SUPER Li brand, carbon nanotubes (CNTs), acetylene black (AB), Ketjen black (KB), and vapor grown carbon fiber (VGCF). The second binder can be polyvinylidene fluoride (PVDF).

[0035] The positive electrode active material, the positive electrode conductive agent, and the second binder are in proportions of 95-97.5%, 1-3.5%, and 1.8-3.2% by weight percentage, respectively.

[0036] The negative electrode tab 2 includes a negative electrode current collector 21 and a negative electrode active layer 22, and the upper surface and the lower surface of the negative electrode current collector 21 are provided with the negative electrode active layer 22. The surface of the negative electrode active layer 22 away from the negative electrode current collector 21 is coated with the surface coating layer 3.

[0037] The negative electrode current collector 21 can be a copper foil. The negative electrode active layer 22 includes graphite, a negative electrode conductive agent, and a third binder. The graphite includes natural graphite and / or artificial graphite. The negative electrode conductive agent includes one of conductive carbon black of SUPER Li brand, acetylene black (AB), Ketjen black (KB), and vapor grown carbon fiber (VGCF). The third binder includes one of polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), polyacrylic acid (PAA), polyvinyl alcohol (PVA), polyamide (PAI), and polyethyleneimine (PEI).

[0038] The graphite, the negative electrode conductive agent, and the third binder are in proportions of 95-97%, 0.5-3%, and 2-3.4% by weight percentage, respectively.

[0039] The preparation steps of the battery tab are as follows: the ceramic material, the phase change material, and the first binder are mixed in proportion and uniformly, and then a solvent is added. After high-speed stirring and dispersion, the surface coating slurry is obtained. The surface coating slurry is coated on the positive and negative surfaces of the positive electrode tab 1 or the negative electrode tab 2 to form the surface coating layer 3. The coating thickness of the single surface of the surface coating layer 3 is 1-5 μm, and the positive electrode composite tab or the negative electrode composite tab is prepared. The positive electrode composite tab or the negative electrode composite tab is cut to the required size.

[0040] In this embodiment, the ceramic material and the phase change material are mixed and coated on the positive electrode tab 1 or the negative electrode tab 2 to form the positive electrode composite tab or the negative electrode composite tab with the surface coating layer 3. During the large current charging and discharging process of the battery, each layer of the positive electrode composite tab and / or the negative electrode composite tab can effectively absorb heat, thereby reducing the overall temperature rise of the battery and the local temperature rise inside the battery.

[0041] Example 2

[0042] This embodiment provides a battery cell, including the battery electrodes from the above embodiments.

[0043] The battery cell includes a positive composite electrode, a separator 4 and a negative electrode 2 arranged in sequence, or a negative composite electrode, a separator 4 and a positive electrode 1 arranged in sequence, or a positive composite electrode, a separator 4 and a negative composite electrode arranged in sequence.

[0044] like Figures 1-5 As shown, the above-mentioned battery cells are fixed by aluminum-plastic film encapsulation and then injected with electrolyte to prepare a lithium-ion battery. The separator 4 is made of polyethylene (PE) or polypropylene (PP). A coating layer 3 is applied to the positive electrode 1 and / or the negative electrode 2, thereby avoiding the increased internal resistance caused by coating the separator 4 with ceramic material, and thus improving the electrochemical performance of the battery.

[0045] The surface coating 3 has good liquid retention capacity and mechanical strength, which enhances the liquid retention capacity of the positive and negative composite electrodes, reduces the expansion rebound effect of the positive and negative composite electrodes, and extends the service life of the battery.

[0046] In the description of this application, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application.

[0047] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0048] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0049] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A battery pole piece, characterized by: The battery pole piece comprises a pole piece body, a surface of the pole piece body is coated with a surface coating (3) to form a composite pole piece, the surface coating (3) comprises a ceramic material and a phase change material, an upper surface of the pole piece body and / or a lower surface thereof is coated with the surface coating (3), the pole piece body comprises a current collector and an active layer, an upper surface of the current collector and a lower surface thereof are provided with the active layer, a surface of the active layer facing away from the current collector is coated with the surface coating (3).

2. The battery pole piece of claim 1, wherein: The ceramic material comprises one of boehmite, alumina, magnesium oxide, and titanium dioxide.

3. The battery pole piece of claim 1, wherein: The phase change material comprises one of paraffin, fatty acid, fatty alcohol, sugar alcohol, polyethylene glycol, and microcapsules formed by a crystalline hydrate salt.

4. The battery pole piece of claim 1, wherein: The surface coating (3) further comprises a first binder.

5. The battery pole piece of claim 4, wherein: The first binder comprises one of polyvinylidene fluoride, sodium carboxymethyl cellulose, sodium alginate, and butyl rubber latex.

6. The battery pole piece of claim 1, wherein: The surface coating (3) has a coating thickness of 1-5 μm.

7. An electric cell characterized by: The battery pole piece comprises a pole piece body, a surface of the pole piece body is coated with a surface coating (3) to form a composite pole piece, the surface coating (3) comprises a ceramic material and a phase change material, an upper surface of the pole piece body and / or a lower surface thereof is coated with the surface coating (3), the pole piece body comprises a current collector and an active layer, an upper surface of the current collector and a lower surface thereof are provided with the active layer, a surface of the active layer facing away from the current collector is coated with the surface coating (3). The battery pole piece comprises a pole piece body, a surface of the pole piece body is coated with a surface coating (3) to form a composite pole piece, the surface coating (3) comprises a ceramic material and a phase change material, an upper surface of the pole piece body and / or a lower surface thereof is coated with the surface coating (3), the pole piece body comprises a current collector and an active layer, an upper surface of the current collector and a lower surface thereof are provided with the active layer, a surface of the active layer facing away from the current collector is coated with the surface coating (3). The battery pole piece comprises a pole piece body, a surface of the pole piece body is coated with a surface coating (3) to form a composite pole piece, the surface coating (3) comprises a ceramic material and a phase change material, an upper surface of the pole piece body and / or a lower surface thereof is coated with the surface coating (3), the pole piece body comprises a current collector and an active layer, an upper surface of the current collector and a lower surface thereof are provided with the active layer, a surface of the active layer facing away from the current collector is coated with the surface coating (3). ​ 8. Vehicle, characterized in that: ​

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