In-Situ Battery EIS Using Vehicle Power Electronics
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Solution Overview
Problem
Existing battery diagnostic techniques require disconnecting batteries from their load and using specialized equipment for detailed analysis, which is often destructive or complex, limiting the ability to obtain accurate in-situ diagnostics of battery health and state.
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 EIS data collection without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If battery diagnostic techniques use specialized equipment and disconnect batteries from load, then measurement precision is improved, but device complexity and ease of operation worsen
Solution Approach 1:
The patent makes the vehicle's existing power electronics (inverter, precharge contactor, DC-DC converter) perform dual functions: their primary function for vehicle operation and an additional function for EIS measurements. By controlling these existing components to operate as variable loads at different switching frequencies, the system obtains impedance spectra without requiring dedicated diagnostic equipment, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The battery system performs its own diagnostic measurements by utilizing its inherent operational components. The vehicle's power electronics serve as both the operational system and the measurement tool, eliminating the need for external specialized equipment. The system measures its own impedance characteristics during normal operation through clever control of existing switches and power electronic components
2Measurement precision
If battery diagnostic techniques disconnect batteries from load, then measurement precision is improved, but productivity and duration of action worsen
Solution Approach 1:
The patent enables continuous EIS measurements to be performed during normal vehicle operation without interrupting the battery's useful work. By utilizing the vehicle's power electronics as variable loads during operational phases (such as during precharge, inverter switching, or DC-DC conversion), the system continuously gathers impedance data across different frequencies while the battery remains connected and functioning, eliminating diagnostic downtime
3Measurement precision
If traditional EIS methods use specialized equipment, then measurement precision is improved, but ease of operation and device complexity worsen
Solution Approach 1:
The vehicle's control system performs EIS measurements autonomously using its existing power electronics. The inverter, precharge contactor, or DC-DC converter are controlled by the vehicle's existing control unit to generate the necessary AC signals and measure impedance responses. This self-service approach maintains measurement precision while simplifying operation, as no separate diagnostic equipment or additional operational steps are required
Data Source
AI summary
A computer system comprising processing circuitry is presented. The processing circuitry is configured to, during control, by the processing circuitry, of an electrical connection between a battery pack and a traction system of a vehicle at a first switching frequency of a set of predetermined switching frequencies, synchronously obtain a first cell voltage and a first cell current of a battery cell of the battery pack; and provide the first cell voltage, the first cell current and the first switching frequency for diagnostic of the battery cell.