Battery Negative Electrode Safety Estimation Under Fast Charging
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Solution Overview
Problem
Lithium metal plating degradation on the negative electrode of batteries is a common cause of ignition and affects the optimal performance and reuse of secondary batteries, necessitating a method to assess negative electrode safety effectively.
Innovation Solution
A method involving a processor that receives charge data from a voltage sensor to estimate negative electrode safety by analyzing differential voltage data at different charge rates, adjusting the charge rate based on safety thresholds to mitigate lithium plating risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charge rate is increased to improve charging speed, then productivity is improved, but lithium metal plating degradation occurs on the negative electrode reducing reliability
Solution Approach 1:
The patent changes the parameter of charge rate dynamically based on the estimated negative electrode safety. The processor adjusts the charge rate within a safe range determined by analyzing differential voltage data, allowing high charging speed when safety is confirmed while preventing lithium plating degradation. This resolves the contradiction by making charge rate a variable parameter rather than a fixed value.
Solution Approach 2:
The patent implements a feedback mechanism where the processor continuously estimates negative electrode safety based on charging voltage data and differential voltage analysis, then uses this estimation to adjust subsequent charging parameters. The system monitors the relationship between charge capacity and voltage at different charge rates, feeds this information back to update safety assessment, and adjusts charging accordingly, creating a closed-loop control system that balances speed and safety.
2Reliability
If charge rate is decreased to prevent lithium plating, then reliability is improved, but productivity deteriorates due to slower charging
Solution Approach 1:
The patent dynamically adjusts the charge rate parameter based on real-time safety estimation rather than using a fixed conservative rate. By analyzing differential voltage data and determining the safe charge rate range, the system allows higher charging speeds when the negative electrode is in a safe state, thus improving productivity while maintaining reliability through continuous parameter optimization.
Solution Approach 2:
The patent makes the charge rate dynamic rather than static. The processor continuously updates the charge rate based on the current state of the negative electrode as estimated from charging voltage data. This dynamic adjustment allows the system to operate at high charge rates when safe and reduce rates only when necessary, optimizing both reliability and productivity throughout the charging process.
3Measurement precision
If charging voltage data is collected at multiple charge rates to improve safety estimation accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent collects charging voltage data at multiple charge rates (first charge rate and second charge rate) to obtain sufficient information for accurate safety estimation. By gathering more data than the minimum single-rate measurement, the system achieves better measurement precision in negative electrode safety assessment. The processor analyzes differential voltage data from multiple charge rates to determine the safe charge rate range with higher accuracy, accepting the additional measurement steps as necessary for reliable safety assessment.
Data Source
AI summary
A method of estimating negative electrode safety by at least one processor includes receiving, by the at least one processor, first charge data for at least one cell from a voltage sensor, receiving, by the at least one processor, second charge data for the at least one cell from the voltage sensor, and estimating, by the at least one processor, negative electrode safety for the at least one cell based on the first charge data and the second charge data, wherein the first charge data and the second charge data have different charge rates.