Battery Pack Internal Short-Circuit Detection via Charge Voltage Tracking
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Solution Overview
Problem
Conventional methods for detecting internal short circuits in battery packs have low precision, leading to potential misjudgments and increased risks of thermal runaway and safety issues in electric vehicles.
Innovation Solution
A battery pack internal short circuit detection method involving a battery management unit that measures voltages of reference and target batteries during charging processes, using balanced discharging to calculate internal short circuit resistance without relying on estimated parameters like SOC or internal resistance, thereby improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If estimation parameters (SOC, internal resistance) are used to identify internal short circuit, then the detection process is simple, but the precision of internal short circuit identification is low and misjudgment occurs easily
Solution Approach 1:
The patent replaces the conventional estimation-based detection method with a voltage measurement-based method. Instead of using estimated parameters like SOC and internal resistance, the invention directly measures voltage values at specific moments during charging processes to calculate internal short circuit resistance, substituting indirect estimation with direct measurement to improve precision.
Solution Approach 2:
The patent introduces a battery management unit as an intermediary that performs balanced discharging of a first battery and measures voltage values. This intermediary component enables the indirect measurement of internal short circuit resistance by using the voltage changes during controlled discharging and charging processes, bridging the gap between observable voltage and the hidden internal short circuit condition.
2Reliability
If conventional estimation methods are used, then the detection process is straightforward, but misjudgment is easily caused and safety risks increase
Solution Approach 1:
The patent implements a feedback mechanism where the battery management unit continuously monitors voltage values during charging and discharging processes. By comparing the measured voltage values with expected values and calculating internal short circuit resistance based on these measurements, the system provides feedback that enables accurate identification of internal short circuits, thereby improving battery safety through reliable detection.
3Measurement precision
If voltage measurement during charging processes is performed, then internal short circuit resistance can be calculated accurately, but the detection process becomes more complex
Solution Approach 1:
The patent performs preliminary actions by having the battery management unit conduct balanced discharging of the first battery before the second charging process. This preliminary discharging action prepares the system for accurate voltage measurements during the subsequent charging process, ensuring that the voltage values measured are meaningful for calculating internal short circuit resistance without requiring complex real-time adjustments during charging.
Data Source
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AI summary
A battery pack internal short circuit detection method and related apparatus, and a vehicle are provided. The method and the apparatus are applicable to an electric vehicle. In the method, a voltage change of a target battery is checked based on voltages of a reference battery in two charging processes, and whether the target battery has an internal short circuit is determined based on the voltage change of the target battery; or, a voltage change of a reference battery is checked based on voltages of a target battery in two charging processes, and whether the target battery has an internal short circuit is determined based on the voltage change of the reference battery. In a process of qualitatively identifying an internal short circuit of a battery, only a voltage value that can be accurately measured is considered, and calculation of an estimated quantity is not involved, thereby improving precision and accuracy of identifying an internal short circuit.