In-Situ Battery EIS Using Traction Switching Signals
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Solution Overview
Problem
Existing battery diagnostic techniques require disconnecting batteries from their load and using specialized equipment, which is destructive, complex, and costly, limiting the ability to accurately estimate state of charge (SOC), state of health (SOH), and internal resistance of batteries in-situ.
Innovation Solution
A computer system with processing circuitry that controls the electrical connection between a battery pack and a traction system of a vehicle, allowing for synchronous acquisition of cell voltage and current at various switching frequencies, enabling in-situ Electrochemical Impedance Spectroscopy (EIS) data collection without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized EIS equipment is used to obtain accurate battery diagnostic data, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing vehicle control unit perform multiple functions: it controls the electrical connection switching and simultaneously acquires voltage and current data for EIS analysis. This eliminates the need for separate specialized EIS measurement equipment while maintaining diagnostic accuracy.
Solution Approach 2:
The vehicle's existing control systems and sensors are utilized to perform battery EIS diagnostics. The control unit uses its inherent capabilities to generate test signals and measure responses, making the system self-sufficient for diagnostic purposes without external specialized equipment.
2Measurement precision
If battery disconnecting from load is performed for diagnostic testing, then measurement accuracy is improved, but productivity and operational continuity deteriorate
Solution Approach 1:
The patent implements periodic switching of the electrical connection at controlled frequencies to generate test signals for EIS analysis. This periodic switching allows accurate impedance measurement across different frequencies while the battery remains connected and operational, enabling diagnostics during normal vehicle operation.
Solution Approach 2:
The battery continues to supply power to the vehicle throughout the diagnostic process. The control unit switches the electrical connection periodically to perform measurements, but the battery remains continuously connected and functional, eliminating the need to stop vehicle operation for diagnostics.
3Adaptability or versatility
If multiple switching frequencies are used for comprehensive EIS spectrum, then diagnostic capability is improved, but measurement time and complexity increase
Solution Approach 1:
The control unit switches the electrical connection at multiple predetermined frequencies in a systematic sequence. Each frequency is applied for a defined period to capture the impedance response, enabling comprehensive EIS spectrum acquisition through time-multiplexed periodic switching rather than requiring simultaneous multi-frequency measurement.
Data Source
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AI summary
A computer system (100) comprising processing circuitry (110) is presented. The processing circuitry (110) is configured to, during control, by the processing circuitry (110), of an electrical connection between a battery pack (200) and a traction system (12) of a vehicle (10) at a first switching frequency (351) of a set of predetermined switching frequencies, synchronously obtain a first cell voltage (321) and a first cell current (331) of a battery cell (210) of the battery pack (200); and provide the first cell voltage (321), the first cell current (331) and the first switching frequency (351) for diagnostic of the battery cell (210).