Online Battery Cell Voltage Monitoring for Internal Short-Circuit Detection
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Solution Overview
Problem
Current methods for detecting internal short-circuits in batteries are inadequate for online detection, particularly in on-board power batteries, as they lack accuracy and timeliness, often misidentifying issues due to inconsistent battery states and contact problems, and existing systems fail to promptly address the risk of combustion.
Innovation Solution
An online detection method that monitors and records the voltage of each cell in a power battery during charging and discharging, using preset thresholds to identify cells with abnormal voltages, and triggers warnings and safety measures upon detection of internal short-circuits, including disabling charging and activating cooling systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If disassembling analysis is used to determine internal short-circuit, then detection accuracy is improved, but online detection capability deteriorates
Solution Approach 1:
The patent replaces the mechanical disassembling analysis method with an electrical measurement system. By monitoring voltage, current, and temperature parameters during battery operation, the system can detect internal short-circuits without physical disassembly, thereby maintaining high detection accuracy while enabling online detection capability.
Solution Approach 2:
The patent introduces intermediate measurement parameters (voltage, current, temperature) as mediators to indirectly detect internal short-circuits. Instead of directly observing the short-circuit condition, the system monitors these intermediary electrical and thermal parameters that change in response to internal short-circuits, enabling non-invasive online detection.
2Device complexity
If static voltage difference method is used, then detection simplicity is improved, but detection timeliness deteriorates
Solution Approach 1:
The patent implements continuous monitoring of voltage, current, and temperature parameters during battery charging and discharging operations. This continuous measurement approach enables timely detection of internal short-circuits as they develop, rather than waiting for static voltage differences to accumulate, thereby improving detection timeliness while maintaining system simplicity.
Solution Approach 2:
The patent performs preliminary detection by continuously monitoring electrical parameters during normal battery operation before significant voltage differences develop. This preliminary monitoring allows early detection of internal short-circuit conditions, enabling preventive action before the condition worsens.
3Reliability
If existing online detection methods based on state of charge difference are used, then detection coverage is improved, but detection accuracy deteriorates
Solution Approach 1:
The patent changes from monitoring only state of charge (a single parameter) to simultaneously monitoring multiple parameters including voltage, current, and temperature. This multi-parameter approach allows the system to distinguish between normal variations in state of charge and actual internal short-circuit conditions, thereby improving detection accuracy while maintaining comprehensive detection coverage.
Solution Approach 2:
The patent applies different detection thresholds and analysis methods for different operating conditions (charging vs. discharging, different temperature ranges). By adapting the detection criteria to local operating conditions, the system improves accuracy in detecting internal short-circuits while maintaining broad detection coverage across various battery states.
Data Source
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AI summary
The present application relates to an online detection method for internal short-circuit of power battery, which comprises the following steps: in the process of charging and discharging, when the state of charge of a power battery is greater than a preset first threshold, monitoring and recording the voltage for each cell in the power battery; in accordance with the recorded historical voltages of each cell, determining whether there is a cell with voltage less than a second threshold in the process of charging, and less than a third threshold in the process of discharging, if so, then marking the corresponding cell as an internal short-circuited cell. The present application could accurately determine whether a malfunction of internal circuit of power battery occurs during the operation of a vehicle, so as to guarantee the safety of the vehicle and the people on-board.