Battery Charging Apparatus Preventing Lithium Deposition
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Solution Overview
Problem
Lithium deposition on the negative electrode plate during battery charging can occur even when the terminal voltage of a lithium secondary cell is below the full-charge voltage, affecting battery performance.
Innovation Solution
A battery charging apparatus and method that calculates and maintains the charging power below the lithium deposition threshold voltage by using pre-calculated tables (I-V dep tables) based on cell temperature, ensuring the cell voltage remains below the deposition threshold, thereby preventing lithium deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charging current or charging power is increased to improve charging speed, then charging efficiency is improved, but lithium deposition occurs on the negative electrode plate
Solution Approach 1:
The patent applies preliminary action by pre-calculating the relationship between charging power and lithium deposition threshold voltage, and storing this data in lookup tables before actual charging occurs. During charging, the controller quickly retrieves the appropriate threshold voltage from the pre-calculated tables based on current cell voltage and temperature, allowing rapid adjustment of charging power to prevent lithium deposition without requiring real-time complex calculations.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting charging power based on cell voltage and temperature parameters. The controller modifies the charging power parameter in real-time to maintain cell voltage below the lithium deposition threshold voltage, preventing lithium deposition while optimizing charging speed. The system also accounts for temperature changes and adjusts parameters accordingly.
2Reliability
If charging power is reduced to prevent lithium deposition, then lithium deposition is prevented, but charging time increases
Solution Approach 1:
The patent applies dynamics by implementing dynamic control of charging power throughout the charging process. The controller continuously monitors cell voltage and temperature, and dynamically adjusts charging power based on real-time conditions. This allows the system to charge at high power when safe and reduce power only when necessary to prevent lithium deposition, optimizing both charging speed and safety.
Solution Approach 2:
The patent applies feedback by continuously monitoring cell voltage and temperature during charging, comparing actual values against the lithium deposition threshold voltage obtained from pre-calculated tables, and adjusting charging power accordingly. This closed-loop feedback control ensures that charging power is optimized to prevent lithium deposition while minimizing charging time.
3Reliability
If cell voltage is maintained below full-charge voltage to prevent lithium deposition, then lithium deposition is prevented, but charging completeness is reduced
Solution Approach 1:
The patent applies parameter changes by adjusting charging power based on temperature and voltage parameters. As the cell approaches full charge or temperature increases, the system dynamically modifies charging parameters to maintain voltage below the lithium deposition threshold while still achieving complete charging. The pre-calculated tables provide different voltage thresholds for different conditions, allowing the system to optimize charging completeness for each scenario.
Data Source
AI summary
A battery charging apparatus is configured to charge a battery with at least one of charging current and charging power set to a predetermined setpoint, wherein the battery includes a lithium secondary cell. The battery charging apparatus calculates a lithium deposition threshold voltage value based on the setpoint, wherein lithium is assumed to be deposited in the lithium secondary cell when a terminal voltage of the lithium secondary cell is above the lithium deposition threshold voltage value. Then, the battery charging apparatus compares the terminal voltage with the calculated lithium deposition threshold voltage value, and controls the at least one of charging current and charging power depending on the comparison.