CN-121983637-A - Preparation method of pole core, battery module and pole core hydrogel layer

CN121983637ACN 121983637 ACN121983637 ACN 121983637ACN-121983637-A

Abstract

A preparation method of a pole core, an electric core, a battery module and a pole core hydrogel layer relates to the technical field of lithium ion batteries. The pole core comprises a pole core body and a hydrogel layer, the pole core body is of a square structure and is provided with two first surfaces which extend in the length direction and the width direction and are oppositely arranged, and the hydrogel layer is at least arranged on the two first surfaces and is located in the middle area of the pole core body in the length direction. The hydrogel layer is used for storing electrolyte, and can play a role in supplementing liquid when the internal expansion stress of the battery cell is increased and the electrolyte is deficient in the later period of circulation, so that the problems of purple spots, black spots, lithium precipitation and the like of pole pieces caused by insufficient infiltration or the electrolyte deficiency in the middle area of the pole core are avoided, the expansion stress of the middle area of the pole core can be effectively relieved by the hydrogel layer, the stress distribution of the hydrogel layer and the edge area is balanced, the problem of deterioration of the performance of the battery cell is solved, in addition, the original structure of the battery cell is changed little by adding the hydrogel layer, and the hydrogel layer is easy to prepare and implement and has high feasibility.

Inventors

HUANG JINJING
YU YANG
YANG FEI
WANG MENG

Assignees

浙江吉利控股集团有限公司
浙江吉曜通行能源科技有限公司
湖州耀宁固态电池研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20251223

Claims (12)

1. The pole core is characterized by comprising a pole core body and a hydrogel layer arranged on the pole core body, wherein the pole core body is of a square structure and is provided with two first surfaces which extend in the length direction and the width direction and are oppositely arranged, the hydrogel layer is arranged on the two first surfaces and is positioned in the middle area of the pole core body in the length direction, the hydrogel layer is of a network structure with interconnected pores, and the pores are used for storing electrolyte.
2. The pole core according to claim 1, wherein the dimension of the hydrogel layer in the length direction of the pole core body is 25% -70% of the length of the first surface, and the distances from the hydrogel layer to both ends of the length direction of the pole core body are equal, and the dimension of the hydrogel layer in the width direction of the pole core body is equal to the width of the first surface.
3. The pole core according to claim 1, wherein the pole core body further has two second surfaces extending in a length direction and a thickness direction and being arranged opposite to each other, the surface of the hydrogel layer is provided with a plurality of groove channels, the plurality of groove channels are distributed at intervals in the length direction of the pole core body, each groove channel extends in the width direction of the pole core body, and the groove channels are used for guiding and diffusing an electrolyte.
4. The pole core according to claim 1, characterized in that the pole core body comprises a positive pole current collector and a negative pole current collector, the positive pole current collector and/or the negative pole current collector being made of a three-dimensional porous material.
5. The pole core is characterized by comprising a pole core body and a hydrogel layer arranged on the pole core body, wherein the pole core body is of a square structure and is provided with two first surfaces which extend in the length direction and the width direction and are oppositely arranged, and two second surfaces which extend in the length direction and the thickness direction and are oppositely arranged, the hydrogel layer is positioned in the middle of the pole core body in the length direction and is arranged on the two first surfaces and the two second surfaces, a four-side surrounding structure which covers the pole core body in the width direction and the thickness direction is formed, and the hydrogel layer is of a network structure with interconnected pores which are used for storing electrolyte.
6. The pole piece of claim 5, wherein the hydrogel layer has a dimension in the length direction of the pole piece body that is 25% -70% of the length of the pole piece body, and the hydrogel layer is equidistant from both ends in the length direction of the pole piece body.
7. The pole core according to claim 5, characterized in that the surface of the hydrogel layer is provided with a plurality of groove channels, which are spaced apart in the length direction of the pole core body, each groove channel extending in the width direction of the pole core body on the first surface and in the thickness direction of the pole core body on the second surface, the groove channels being used for guiding and diffusing the electrolyte.
8. The pole piece of claim 5, wherein the pole piece body comprises a positive current collector and a negative current collector, the positive current collector and/or the negative current collector being made of a three-dimensional porous material.
9. A cell comprising a housing, and an electrolyte disposed within the housing and the electrode core of any one of claims 1-8.
10. A battery module comprising the cell as set forth in claim 9.
11. A method of preparing a pole core hydrogel layer according to any one of claims 1 to 8, comprising: Calculating the expansion stress and expansion displacement of the single cell based on the design parameters of the battery module; Calculating Young's modulus of the required hydrogel material based on design parameters of the single cell and combining the expansion stress and the expansion displacement of the single cell in the battery module; Synthesizing a hydrogel material based on the young's modulus; and drying the hydrogel material to obtain a hydrogel layer.
12. The method of manufacturing according to claim 11, further comprising: And soaking the hydrogel layer in an electrolyte solution to enable the hydrogel layer to adsorb the electrolyte until the hydrogel layer is saturated.

Description

Preparation method of pole core, battery module and pole core hydrogel layer Technical Field The application relates to the technical field of lithium ion batteries, in particular to a pole core, an electric core, a battery module and a preparation method of a pole core hydrogel layer. Background In the field of power cells, square aluminum-case cells, typified by blade cells, are facing a serious technical challenge. The battery cells have the characteristic that the performance of the battery cells shows obvious gradient distribution in the length direction due to the large length-width ratio, and particularly, the middle area in the length direction becomes a main area causing the performance degradation of the battery cells. The core reasons of the problem are that 1. The irreversible expansion is continuously aggravated, namely, the anode and cathode materials can generate irreversible volume expansion due to repeated intercalation and deintercalation of lithium ions in a long-term charge and discharge cycle of the lithium ion battery, which is a fundamental cause of rapid and irreversible increase of the expansion force of the battery cell, particularly in a super rapid charge and discharge scene, the expansion process can be rapidly accelerated by high-rate charge and discharge, and 2. The inherent defect of electrolyte infiltration is that in the manufacturing process of the battery cell, the electrolyte injected from a liquid injection port can fill gaps around the battery cell preferentially and then slowly infiltrate to the middle part of the battery cell, so that the middle area of the battery cell naturally becomes a weak area of electrolyte infiltration. The problems of the expansion of the battery cell and the poor infiltration of the electrolyte can be mutually overlapped, and side reactions such as purple spots, black spots, lithium precipitation and the like are easy to occur in the middle area of the battery cell under serious conditions. The occurrence of these side reactions can further cause rapid consumption of electrolyte in the middle region of the battery cell, exacerbate irreversible expansion in the middle region of the battery cell, lead to rapid degradation of the performance of the battery cell, rapid increase of expansion stress in the battery module, and significant rise of thermal runaway risk, thereby bringing about safety risk of dual levels of the single battery cell and the battery module. Disclosure of Invention Accordingly, the present application is directed to a pole core, a battery cell, a battery module, and a method for preparing a hydrogel layer in the pole core, so as to solve at least one of the above problems. The application provides a pole core, which comprises a pole core body and a hydrogel layer arranged on the pole core body, wherein the pole core body is of a square structure and is provided with two first surfaces which extend in the length direction and the width direction and are oppositely arranged, the hydrogel layer is arranged on the two first surfaces and is positioned in the middle area of the pole core body in the length direction, and the hydrogel layer is of a network structure with interconnected pores which are used for storing electrolyte. With reference to the first aspect, in some optional embodiments, a dimension of the hydrogel layer in a length direction of the pole body is 25% -70% of a length of the first surface, and distances from the hydrogel layer to both ends of the pole body in the length direction are equal, and a dimension of the hydrogel layer in a width direction of the pole body is equal to a width of the first surface. In combination with the first aspect, in some optional embodiments, the pole core body further has two second surfaces extending in a length direction and a thickness direction and being oppositely arranged, and the surface of the hydrogel layer is provided with a plurality of groove channels, the plurality of groove channels are distributed at intervals in the length direction of the pole core body, each groove channel extends along the width direction of the pole core body, and the groove channels are used for guiding and diffusing electrolyte. With reference to the first aspect, in some alternative embodiments, the electrode core body includes a positive electrode current collector and a negative electrode current collector, and the positive electrode current collector and/or the negative electrode current collector are made of a three-dimensional porous material. The application provides another pole core, which comprises a pole core body and a hydrogel layer arranged on the pole core body, wherein the pole core body is of a square structure and is provided with two first surfaces which extend in the length direction and the width direction and are oppositely arranged, and two second surfaces which extend in the length direction and the thickness direction and are oppositely arranged, the hydrogel la