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CN-224217501-U - Electrochemical device

CN224217501UCN 224217501 UCN224217501 UCN 224217501UCN-224217501-U

Abstract

The application relates to an electrochemical device, which comprises an electrode assembly, wherein the electrode assembly comprises a negative electrode group, the negative electrode group comprises at least one negative electrode plate, the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side surface of the negative electrode current collector, the negative electrode film layer comprises a silicon-based material, the positive electrode group comprises a phosphate positive electrode active material and a ternary material, the positive electrode group comprises at least one positive electrode plate which is alternately stacked with the negative electrode plate, each positive electrode plate respectively comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side surface of the positive electrode current collector, the positive electrode film layer comprises a first film layer, a second film layer or any one of a laminated body formed by the first film layer and the second film layer, the first film layer comprises the ternary material, and the second film layer comprises the phosphate positive electrode active material. The electrochemical device provided by the application can maintain high energy density and simultaneously remarkably improve the low-temperature performance of the electrochemical device.

Inventors

  • ZHENG HONGPENG
  • LIU ZHIMIN
  • ZHAO JIAXING

Assignees

  • 北京车和家汽车科技有限公司

Dates

Publication Date
20260508
Application Date
20250227

Claims (10)

  1. 1. An electrochemical device comprising an electrode assembly, the electrode assembly comprising: The negative electrode assembly comprises at least one negative electrode plate, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side surface of the negative electrode current collector, and the negative electrode film layer comprises a silicon-based material; The positive electrode group comprises phosphate positive electrode active materials and ternary materials, the positive electrode group comprises at least one positive electrode plate which is alternately stacked with the negative electrode plate, each positive electrode plate comprises a positive electrode current collector and a positive electrode film layer which is arranged on at least one side surface of the positive electrode current collector, the positive electrode film layer comprises a first film layer, a second film layer and any one of laminated bodies formed by the first film layer and the second film layer, the positive electrode active materials contained in the first film layer are ternary materials, and the positive electrode active materials contained in the second film layer are phosphate positive electrode active materials.
  2. 2. The electrochemical device of claim 1, wherein at least one of the positive electrode sheets comprises a first positive electrode sheet, In the first positive electrode plate, the positive electrode film layer is arranged on one side surface of the positive electrode current collector, and the other side surface of the positive electrode current collector is exposed.
  3. 3. The electrochemical device of claim 1, wherein at least one of the positive electrode sheets comprises a second positive electrode sheet, In the second positive plate, the positive film layers are arranged on the two side surfaces of the positive current collector.
  4. 4. The electrochemical device according to claim 3, wherein in the second positive electrode sheet, the positive electrode film layers disposed on both sides of the positive electrode current collector contain the same positive electrode active material.
  5. 5. The electrochemical device according to claim 3, wherein in the second positive electrode sheet, the positive electrode film layers disposed on both sides of the positive electrode current collector contain different positive electrode active materials.
  6. 6. The electrochemical device of claim 5, wherein in the second positive electrode sheet, The positive electrode film layer arranged on one side of the positive electrode current collector is the first film layer, the positive electrode film layer arranged on the other side of the positive electrode current collector is the second film layer, or The positive electrode film layer arranged on one side of the positive electrode current collector is the first film layer, the positive electrode film layer arranged on the other side of the positive electrode current collector is the laminated body formed by the first film layer and the second film layer, or The positive electrode film layer arranged on one side of the positive electrode current collector is the second film layer, and the positive electrode film layer arranged on the other side of the positive electrode current collector is the laminated body formed by the first film layer and the second film layer.
  7. 7. The electrochemical device according to any one of claims 1 to 6, wherein in the laminate, the first film layer is disposed between the second film layer and the positive electrode current collector.
  8. 8. The electrochemical device according to any one of claims 1 to 6, wherein in the laminate, the second film layer is disposed between the first film layer and the positive electrode current collector.
  9. 9. The electrochemical device of any one of claims 1 to 8, further comprising a housing having a receiving cavity within which the electrode assembly is disposed, and the positive electrode film layer adjacent the positive electrode tab of the housing comprises the second film layer.
  10. 10. The electrochemical device according to any one of claims 1 to 9, wherein in the positive electrode group, the number of the second film layers is 1% to 10% with respect to the sum of the first film layers and the second film layers.

Description

Electrochemical device Technical Field The application belongs to the technical field of electrochemistry, and particularly relates to an electrochemical device. Background New energy automobiles are being developed greatly in recent years as an important means for realizing carbon emission reduction worldwide. As a common electrochemical device, a lithium ion battery is the most popular electrochemical device due to the characteristics of high working voltage, long service life and environmental friendliness, and is widely applied to the fields of pure electric vehicles, hybrid electric vehicles, smart grids and the like. In recent years, there have been demands for electrochemical devices, for example, for electrochemical devices having high energy density. The ternary material and the silicon-based negative electrode material have higher gram capacity, and the industry has started to improve the energy density of an electrochemical device (ternary silicon-doped system) by adding the silicon-based negative electrode material into a negative electrode plate and adding the ternary material into a positive electrode plate. However, ternary silicon-doped systems, while having a high energy density, have poor performance at low temperatures. The improvement of the performance of the ternary silicon-doped system at low temperature is a technical problem to be solved while maintaining the high energy density of the ternary silicon-doped system. Disclosure of utility model In view of the above, a primary object of the present application is to provide an electrochemical device. The electrochemical device has improved power performance and energy retention at low temperatures while having a high energy density. In order to achieve the above purpose, the technical scheme of the application is realized as follows: The present application provides an electrochemical device including an electrode assembly, the electrode assembly including: The negative electrode group comprises at least one negative electrode plate, the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side surface of the negative electrode current collector, and the negative electrode film layer comprises a silicon-based material; The positive electrode group comprises a phosphate positive electrode active material and a ternary material, the positive electrode group comprises at least one positive electrode plate which is alternately stacked with a negative electrode plate, each positive electrode plate comprises a positive electrode current collector and a positive electrode film layer which is arranged on at least one side surface of the positive electrode current collector, the positive electrode film layer comprises any one of a first film layer, a second film layer and a lamination body formed by the first film layer and the second film layer, the positive electrode active material contained in the first film layer is the ternary material, and the positive electrode active material contained in the second film layer is the phosphate positive electrode active material. In some embodiments, the at least one positive electrode sheet comprises a first positive electrode sheet in which a positive electrode film layer is disposed on one side surface of the positive electrode current collector and the other side surface of the positive electrode current collector is exposed. In some embodiments, the at least one positive electrode sheet includes a second positive electrode sheet in which positive electrode film layers are provided on both side surfaces of the positive electrode current collector. In some embodiments, in the second positive electrode sheet, positive electrode film layers disposed on both sides of the positive electrode current collector contain the same positive electrode active material. In some embodiments, in the second positive electrode sheet, positive electrode film layers disposed on both sides of the positive electrode current collector contain different positive electrode active materials. In some embodiments, in the second positive electrode sheet, the positive electrode film layer disposed on one side of the positive electrode current collector is a first film layer, and the positive electrode film layer disposed on the other side of the positive electrode current collector is a second film layer. In some embodiments, the positive electrode layer disposed on one side of the positive electrode current collector is a first layer, and the positive electrode layer disposed on the other side of the positive electrode current collector is the laminate of the first layer and the second layer. In some embodiments, the positive electrode layer disposed on one side of the positive electrode current collector is a second layer, and the positive electrode layer disposed on the other side of the positive electrode current collector is the laminate formed