Battery Cell Fast-Charging Current Limits Using Rebound Potential
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Solution Overview
Problem
Existing fast charging methods for lithium batteries are limited by 'trials and errors' without considering the battery cell's rebound potential, failing to fully exploit the charging capacity and leading to risks of lithium precipitation.
Innovation Solution
The method divides the charging process into n stages based on electric quantity, determining rebound and polarization potential values, and calculating charging current values to set target fast charging current limits that ensure safe and efficient charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a degree reduction constant current charging strategy is adopted, then the charging speed is improved, but the risk of lithium precipitation increases and the battery cell's fast charging capacity is not fully exploited
Solution Approach 1:
The charging process is divided into multiple charging stages with different current limits. The method segments the charging process based on the battery cell's state of charge and calculates appropriate current limits for each stage, preventing lithium precipitation while maximizing charging speed. This is achieved by dividing the charging process into initial stage, middle stage, and final stage, each with optimized current limits.
Solution Approach 2:
The method dynamically adjusts charging current limits based on battery cell parameters such as state of charge, temperature, and impedance characteristics. By changing the current limit parameter adaptively across different charging stages rather than using a fixed current reduction strategy, the system optimizes both charging speed and safety.
2Productivity
If the charging rate is increased to improve charging speed, then the charging efficiency is improved, but the tolerable charging rate varies in different charging states and temperatures leading to lithium precipitation risk
Solution Approach 1:
The charging current limit is made dynamic rather than static. The method calculates and adjusts the current limit based on real-time battery cell conditions including state of charge, temperature, and impedance. This dynamic adjustment allows the system to adapt to varying charging states and temperatures, maintaining optimal charging efficiency while preventing lithium precipitation.
Solution Approach 2:
The system incorporates feedback mechanisms by continuously monitoring battery cell parameters and using them to adjust the charging current limit. The method uses measured impedance and state of charge information to feedback-control the current limit, ensuring the charging rate remains within safe boundaries while maximizing charging efficiency.
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 approach fully exploits the battery cell's charging capacity, reducing the risk of lithium precipitation and improving charging efficiency while saving resources and costs.
Implementation Method 1
The demand for lithium batteries as a dominant energy source has been increasing with the development of new energy vehicles
Implementation Method 2
determining a rebound potential value and a polarization potential value of each charging stage
Data Source
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AI summary
Provided are a method and apparatus for determining a fast charging current limit of a battery cell, an electronic device, and a medium. The method includes: dividing a process of charging the battery cell into n charging stages based on electric quantity; determining a rebound potential value and a polarization potential value of each charging stage and a difference value between allowable lowest negative electrode potentials of adjacent charging stages in an order from larger to smaller values of n; calculating one or more charging current values of each charging stage based on the rebound potential value and the polarization potential value of the charging stage and the difference value between the allowable lowest negative electrode potentials of adjacent charging stages; and determining target fast charging current limits corresponding to different charging stages that satisfy a preset condition based on the one or more charging current values of each of the n charging stages. According to the embodiments of the present disclosure, the characteristic of the rebound potential of the battery cell is fully exploited to calculate a fast charging capacity limit of the battery cell, which greatly saves samples and test resources and has the advantages of high efficiency, accuracy, and cost-effectiveness.