Battery Separator Closed-Pore Structure for Lithium Plating Control
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Solution Overview
Problem
Lithium-ion batteries face challenges with lithium precipitation during charging, which can lead to reduced energy density, shortened cycle life, and safety risks due to potential thermal runaway and internal short circuits.
Innovation Solution
Incorporating a closed-pore portion in the separator of the electrode assembly, specifically in regions prone to lithium precipitation, to block de-intercalated ions from being re-intercalated into the anode, thereby reducing lithium precipitation and enhancing safety and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the separator allows free ion movement to maintain good electrochemical performance, then charging efficiency is improved, but lithium precipitation occurs leading to reduced safety and shorter cycle life
Solution Approach 1:
The separator is designed with different pore structures in different regions: the first region (prone to lithium precipitation) has closed-pore portions to block ion movement and prevent lithium crystallization, while the second region maintains open pores for normal ion transport. This local differentiation allows the separator to simultaneously prevent lithium precipitation in critical areas while maintaining good electrochemical performance in other areas.
2Reliability
If the separator structure is modified to prevent lithium precipitation, then battery safety is improved, but production complexity increases
Solution Approach 1:
The pore closing degree in the first region of the separator is controlled within a specific range (30%-70%) through parameter optimization. This moderate pore closing is sufficient to block lithium ion movement and prevent crystallization while maintaining reasonable ion transport in other regions, achieving a balance between safety improvement and structural simplicity.
3Reliability
If closed-pore portions are added to the separator to block ion channels, then lithium precipitation is reduced, but manufacturing difficulty increases
Solution Approach 1:
The closed-pore portions are pre-formed in the separator during the separator manufacturing process itself, rather than being added as a separate post-processing step. This preliminary formation of the pore structure allows the modified separator to be integrated into the existing battery assembly line without requiring additional complex processing equipment or steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The closed-pore portion effectively reduces lithium precipitation, improving the safety and service life of the battery cell while simplifying production processes by blocking ion movement channels and preventing lithium crystallization.
Implementation Method 1
the closed-pore portion is configured to block at least some ions de-intercalated from the cathode plate located on one side of the closed-pore portion from being intercalated into the anode plate located on the other side of the closed-pore portion
Implementation Method 2
a separator, where the separator is configured to separate the cathode plate from the anode plate
Data Source
AI summary
The present application provides an electrode assembly and a processing method and apparatus therefor, a battery cell, a battery, and a power consuming device. The electrode assembly includes: a cathode plate, an anode plate, and a separator, where the separator is configured to separate the cathode plate from the anode plate, a closed-pore portion is provided in part of the region of the separator, and the closed-pore portion is configured to block at least some ions de-intercalated from the cathode plate located on one side of the closed-pore portion from being intercalated into the anode plate located on the other side of the closed-pore portion. Heating the separator to form the closed-pore portion can reduce the occurrence of lithium precipitation.