Battery Pack Voltage Comparison for Internal Short Detection
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Solution Overview
Problem
Conventional methods for identifying internal short circuits in batteries suffer from low precision and are prone to misjudgment, as they rely on estimation parameters.
Innovation Solution
A method involving the battery management unit to measure and compare voltages of reference and target batteries at different charging stages, using balanced discharging processes to quantify internal short circuit resistance without relying on estimated quantities like state of charge (SOC) or internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If estimation parameters are used to identify internal short circuits, then the detection process is simplified, but the precision and accuracy of detection deteriorates
Solution Approach 1:
The patent replaces estimation-based detection methods with a physics-based electrical measurement system. By substituting the mechanical/empirical estimation approach with an electrical measurement system that uses voltage comparisons and controlled charging/discharging processes, the patent achieves both simplified implementation and high precision detection of internal short circuits.
Solution Approach 2:
The patent introduces a reference battery as an intermediary element to enable accurate measurement of the target battery's internal short circuit resistance. The reference battery serves as a mediator that provides a known baseline for comparison, allowing the system to isolate and measure the specific resistance caused by internal short circuits without needing complex estimation algorithms.
2Ease of manufacture
If conventional estimation methods are used, then the calculation process is simpler, but misjudgment occurs more frequently
Solution Approach 1:
The patent replaces unreliable estimation-based calculation methods with a reliable electrical measurement system. By substituting the empirical estimation approach with controlled electrical measurements during charging and discharging phases, the system achieves both computational simplicity and high detection reliability, eliminating frequent misjudgments.
Solution Approach 2:
The patent implements a feedback mechanism by continuously monitoring voltage differences between the reference battery and target battery during controlled charging and discharging cycles. This feedback allows the system to dynamically adjust measurements and accurately determine internal short circuit resistance, ensuring high reliability while maintaining calculation simplicity through standardized protocols.
3Device complexity
If internal short circuit resistance is calculated using estimated quantities like SOC, then the calculation is more straightforward, but the accuracy deteriorates
Solution Approach 1:
The patent extracts the internal short circuit resistance measurement from the complex estimation of state of charge (SOC) and other battery parameters. By isolating the resistance measurement through controlled charging and discharging cycles with voltage comparisons, the system eliminates the need to accurately estimate multiple interdependent parameters, thereby achieving both calculation simplicity and measurement accuracy.
Solution Approach 2:
The reference battery acts as an intermediary that enables direct measurement of internal short circuit resistance without relying on SOC estimation. By comparing the voltage responses of the target battery and reference battery under identical controlled conditions, the system directly determines the resistance difference caused by internal short circuits, avoiding the accuracy losses associated with estimating multiple battery state parameters.
Data Source
AI summary
A battery pack internal short circuit detection method applicable to an electric vehicle includes checking a voltage change of a target battery based on voltages of a reference battery in two charging processes, and determining whether the target battery has an internal short circuit based on the voltage change of the target battery; or checking a voltage change of a reference battery based on voltages of a target battery in two charging processes, and determining whether the target battery has an internal short circuit based on the voltage change of the reference battery.