CN-224217467-U - Silicon-doped anode active layer, anode piece, battery cell and electric equipment

Abstract

The application provides a silicon-doped anode active layer which comprises particles, wherein the particles comprise an inner core and a flexible binder outer layer, the flexible binder outer layer is fully or semi-wrapped on the outer surface of the inner core, the inner core comprises graphite particles, silicon anode particles and a conductive agent, and the graphite particles, the silicon anode particles and the conductive agent are connected through a rigid binder. Compared with the prior art, the positive-direction design of the internal hardness and the external softness of the adhesive is adopted, the internal layer rigid adhesive dissipates most of internal stress caused by volume change in the expansion process of the silicon negative electrode particles, the external layer flexible adhesive is used as a buffer layer for absorbing residual stress, the internal hardness and the external softness are adopted to design the double-layer adhesive, so that the stress release in the negative electrode circulation process is effectively relieved, the stability of a negative electrode interface is ensured, and the cycle life of the battery core is prolonged.

Inventors

• FANG HUI
• LIU ZHIMIN
• LI WEI
• ZHAO JIAXING

Assignees

• 北京车和家汽车科技有限公司

Dates

Publication Date

20260508

Application Date

20250331

Claims (10)

1. 1. The silicon-doped anode active layer is characterized by comprising particles, wherein the particles comprise an inner core and a flexible binder outer layer, the flexible binder outer layer is fully or semi-wrapped on the outer surface of the inner core, the inner core comprises graphite particles, silicon anode particles and a conductive agent, and the graphite particles, the silicon anode particles and the conductive agent are connected through a rigid binder.
2. 2. The silicon-doped anode active layer according to claim 1, wherein the particle size of the graphite particles is 10 to 20 μm, and the particle size of the silicon anode particles is 5 to 15 μm.
3. 3. The silicon-doped anode active layer of claim 1, wherein the outer surface of the inner core is a rigid binder layer.
4. 4. The silicon-doped anode active layer of claim 1, wherein the thickness of the flexible binder outer layer is 20-50 nm.
5. 5. The silicon-doped anode active layer of claim 1, wherein the silicon-doped anode active layer comprises a first silicon-doped anode active sub-layer and a second silicon-doped anode active sub-layer stacked; The first silicon-doped anode active sublayer comprises inner cores which are connected through a rigid binder; The second silicon-doped anode active sub-layer comprises an inner core and a flexible adhesive outer layer, and the flexible adhesive outer layer is semi-wrapped on the outer surface of the inner core.
6. 6. The silicon-doped anode active layer of claim 5, wherein the thickness ratio of the first silicon-doped anode active sub-layer to the second silicon-doped anode active sub-layer is 1 (0.001-0.002).
7. 7. The negative electrode sheet is characterized by comprising a current collector and the silicon-doped negative electrode active layer according to any one of claims 1 to 6, wherein the silicon-doped negative electrode active layer is arranged on at least one side surface of the current collector.
8. 8. The negative electrode tab of claim 7, wherein the silicon-doped negative electrode active layer comprises a first silicon-doped negative electrode active sub-layer and a second silicon-doped negative electrode active sub-layer stacked together, the first silicon-doped negative electrode active sub-layer being in contact with a current collector.
9. 9. A battery cell, comprising the silicon-doped anode active layer according to any one of claims 1 to 6 or the anode sheet according to claim 7 or 8.
10. 10. A powered device comprising a negative electrode sheet according to claim 7 or 8 or a battery cell according to claim 9.

Description

Silicon-doped anode active layer, anode piece, battery cell and electric equipment Technical Field The application belongs to the technical field of batteries, and particularly relates to a silicon-doped anode active layer, an anode plate, a battery cell and electric equipment. Background The lithium ion battery has the advantages of high energy density, long cycle life and the like, and is remarkable in a plurality of electrochemical energy storage devices, and is widely applied to the fields of portable electronic equipment and electric automobiles at present. With the increasing energy demand, the conventional graphite anode has failed to meet the higher energy density demand, so development of a novel anode material is urgently required. SiO materials are increasingly favored by the industry because of their ultra-high specific capacity (SiO-1713.2 mAh/g Vs graphite-372 mAh/g). However, the high volume expansion rate (160 percent) of the material inevitably collapses the structure in the long-cycle process, so that the material is pulverized and fails, the cycle performance is deteriorated, and the application of the material is limited. At present, the volume expansion problem of the silicon cathode is mainly solved by methods such as carbon coating, hole structure design and the like, but the commercialization is difficult to realize due to complex synthesis process, complicated steps and high cost. The Chinese patent with publication number CN116470054A ensures the stability of the electrode structure by manufacturing a supermolecule adhesive with certain mechanical strength and viscosity, and the Chinese patent with publication number CN117050679A is constructed on a current collector in situ by manufacturing a triple cross-linking adhesive, so that the formed artificial protection layer can inhibit silicon expansion and ensure the integrity of a silicon negative electrode. However, since the mechanism is to relieve the collapse process of the structure by relieving stress release, the above measures all depend on a certain mechanical strength. Based on the electrode failure process, how to efficiently release stress is critical to solving such problems, but there is still a lack of related forward designs. Disclosure of utility model In view of the above, the technical problem to be solved by the present application is to provide a silicon-doped anode active layer, an anode sheet, a battery cell and electric equipment capable of improving the stability of the anode interface. The application provides a silicon-doped anode active layer which comprises particles, wherein the particles comprise an inner core and a flexible binder outer layer, the flexible binder outer layer is fully or semi-wrapped on the outer surface of the inner core, the inner core comprises graphite particles, silicon anode particles and a conductive agent, and the graphite particles, the silicon anode particles and the conductive agent are connected through a rigid binder. Preferably, the particle size of the graphite particles is 10-20 mu m, and the particle size of the silicon anode particles is 5-15 mu m. Preferably, the outer surface of the inner core is a rigid adhesive layer. Preferably, the thickness of the outer layer of the flexible adhesive is 20-50 nm. Preferably, the silicon-doped anode active layer comprises a first silicon-doped anode active sub-layer and a second silicon-doped anode active sub-layer which are stacked; The first silicon-doped anode active sublayer comprises inner cores which are connected through a rigid binder; The second silicon-doped anode active sub-layer comprises an inner core and a flexible adhesive outer layer, and the flexible adhesive outer layer is semi-wrapped on the outer surface of the inner core. Preferably, the thickness ratio of the first silicon-doped anode active sub-layer to the first silicon-doped anode active sub-layer is 1 (0.001-0.002). The application also provides a negative electrode plate which comprises a current collector and the silicon-doped negative electrode active layer, wherein the silicon-doped negative electrode active layer is arranged on at least one side surface of the current collector. Preferably, the silicon-doped anode active layer comprises a first silicon-doped anode active sub-layer and a second silicon-doped anode active sub-layer which are stacked, wherein the first silicon-doped anode active sub-layer is in contact with a current collector. The application also provides a battery cell which comprises the silicon-doped anode active layer or the anode piece. Preferably, the battery cell further comprises a positive plate and a diaphragm, and the diaphragm is arranged between the negative plate and the positive plate. The application also provides electric equipment, which comprises the negative plate or the battery cell. The application provides a silicon-doped anode active layer which comprises particles, wherein the particles comprise an inner core