Battery Cell Separator Thickness for Electrolyte Retention Balance
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Solution Overview
Problem
The thin design of the negative electrode plate in metal battery cells results in poor electrolyte retention, leading to electrolyte depletion and performance degradation, affecting the cycle life of the battery.
Innovation Solution
Increasing the ratio of the separator thickness to the negative electrode plate thickness to a range of 0.07 ≤ H1/H2 ≤ 241.18, and optionally enhancing the separator with a functional coating, improves electrolyte retention and mitigates performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the separator thickness is increased to improve electrolyte retention, then the cycle life is prolonged, but the ion transport path increases leading to higher liquid-phase impedance and reduced specific capacity performance
Solution Approach 1:
The patent optimizes the separator thickness parameter to a specific range (H1/H2 ≥ 0.07) to achieve the best balance between electrolyte retention and ion transport efficiency, resolving the contradiction between cycle life and specific capacity performance
Solution Approach 2:
The patent employs a composite structure combining the separator with a functional coating layer that has electrolyte retention functionality, enabling the system to maintain both good electrolyte retention and ion transport performance simultaneously
2Quantity of substance
If the separator thickness is increased to retain more electrolyte, then the electrolyte depletion is mitigated, but the energy density is reduced due to increased liquid-phase impedance
Solution Approach 1:
The patent optimizes the separator thickness parameter to a specific range (H1/H2 ≥ 0.07) to achieve the best balance between electrolyte retention and energy density, resolving the contradiction between these two parameters
Solution Approach 2:
The patent employs a composite structure combining the separator with a functional coating layer that has electrolyte retention functionality, enabling the system to maintain both good electrolyte retention and high energy density
3Weight of moving object
If the negative electrode plate is designed to be thin to improve energy density, then the specific capacity performance is improved, but the electrolyte retention ability deteriorates
Solution Approach 1:
The patent employs a composite structure combining the separator with a functional coating layer that has electrolyte retention functionality, compensating for the poor electrolyte retention of thin negative electrode plates
Solution Approach 2:
The patent optimizes the ratio between separator thickness and negative electrode plate thickness (H1/H2 ≥ 0.07) to ensure adequate electrolyte retention even when the negative electrode plate is thin
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
This configuration enhances electrolyte retention, reduces the risk of depletion, and prolongs the cycle life of the battery cell while maintaining energy density and specific capacity performance.
Implementation Method 1
increasing the thickness H1 of the separator enables retention of more electrolyte
Data Source
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AI summary
Embodiments of the present application provide a battery cell, a battery, and an electric apparatus. The battery cell includes an electrode assembly, the electrode assembly including a negative electrode plate, a positive electrode plate, and a separator, the separator being configured to isolate the negative electrode plate and the positive electrode plate; where a ratio of a thickness of the separator to a thickness of the negative electrode plate is greater than or equal to 0.07. The battery cell provided in the embodiments of the present application can improve the electrolyte retention capacity of the battery by controlling the thicknesses of the separator and the negative electrode plate, mitigating the decomposition or volatilization of the electrolyte in the battery cell, thereby prolonging the cycle life of the battery.