Li-Ion Battery Plating Detection Using Concentration Difference
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Solution Overview
Problem
Existing lithium-ion rechargeable battery charging technologies fail to accurately determine lithium deposition, which depends on the difference between surface and average concentrations of the negative electrode active material, even when other variables like current, charge rate, and temperature are constant.
Innovation Solution
A state determination device that uses a difference variable indicating the difference between surface and average concentrations of the negative electrode active material to determine lithium deposition, incorporating additional variables such as charge time and temperature to enhance accuracy, and sets an optimal charge current limit to prevent lithium deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charge current is increased to improve charging speed, then productivity is improved, but lithium deposition occurs reducing reliability
Solution Approach 1:
The patent changes the parameter used for deposition determination from conventional variables (current, temperature, charge rate) to a new parameter: the difference variable indicating the difference between surface concentration and average concentration of lithium in the negative electrode active material. This parameter change enables accurate deposition determination even at high charge currents, allowing faster charging without lithium deposition.
2Measurement precision
If conventional variables (current, temperature, charge rate) are used for deposition determination, then device complexity is reduced, but measurement precision is insufficient
Solution Approach 1:
The patent substitutes the conventional mechanical/electrical measurement approach (using current, temperature, charge rate sensors) with a concentration difference-based determination method. By calculating the difference variable from concentration data, the system achieves higher measurement precision without requiring additional physical sensors or complex hardware modifications.
Data Source
AI summary
A state determination device for a lithium-ion rechargeable battery includes a storage device and an execution device. The storage device stores deposition determination mapping data for defining a deposition determination mapping that uses a difference variable as an input variable and outputs information on whether lithium is deposited on a negative electrode of the lithium-ion rechargeable battery. The difference variable indicate information on a difference between a surface concentration of the negative electrode active material and an average concentration of the negative electrode active material in the lithium-ion rechargeable battery. The execution device is configured to execute a determination acquisition process for acquiring a value of the input variable of the deposition determination mapping, and a determination process for determining deposition of lithium by inputting the value of the input variable of the deposition determination mapping to the deposition determination mapping.