Secondary Battery Charging with SOH-Based Lithium Replenishment
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Solution Overview
Problem
Existing charging methods for secondary batteries result in irreversible consumption of active ions due to the formation of a solid electrolyte interface (SEI) film, leading to irreversible capacity loss and challenges in improving energy density.
Innovation Solution
A method for supplementing lithium in secondary batteries by detecting the State Of Health (SOH) and post-supplementing lithium when SOH is low, performing a normal charge-discharge cycle when active lithium content is sufficient, and re-supplementing as needed to maintain high active lithium content, using a lithium-supplementing material with controlled activation and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant current charging method is used, then charging speed is improved, but battery life is reduced due to overcharging and memory effect
Solution Approach 1:
The charging method dynamically adjusts charging parameters based on real-time battery state. The controller monitors battery voltage and current, and automatically switches between constant current charging (for speed) and constant voltage charging (for safety and battery life), resolving the contradiction between charging speed and battery reliability
Solution Approach 2:
The system implements feedback control by continuously monitoring battery voltage and current during charging. Based on the feedback signals, the controller adjusts charging parameters to prevent overcharging and memory effect, thereby extending battery life while maintaining efficient charging speed
2Reliability
If constant voltage charging method is used, then battery life is extended by preventing overcharging, but charging speed is reduced
Solution Approach 1:
The charging system dynamically switches between constant current and constant voltage modes based on battery state. During early charging stages, constant current mode provides fast charging; when battery voltage approaches full charge, it transitions to constant voltage mode to prevent overcharging, thus achieving both fast charging and battery life extension
3Measurement precision
If multiple charging parameters are measured and compared, then charging accuracy is improved, but processing time is increased
Solution Approach 1:
The system performs preliminary measurements of multiple charging parameters (voltage, current, temperature) at the beginning of charging and at key transition points. This preliminary action allows the controller to pre-determine charging stages and switch between modes without continuous real-time comparison, maintaining charging accuracy while reducing processing time
Data Source
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AI summary
Examples of the present application provide a charging method for a secondary battery, a charging apparatus for a secondary battery, a charging device, and a computer storage medium. The method includes: acquiring a first state of health SOH1 of the secondary battery when the secondary battery is at a preset charging node; activating the lithium-supplementing material when the SOH1 is less than or equal to a first threshold, to supplement lithium for the secondary battery; performing a first charging process on the secondary battery; determining a second state of health SOH2 of the secondary battery based on a working parameter of the secondary battery in the first charging process; and charging the secondary battery when the SOH2 is greater than a second threshold.