Battery System Detecting Internal Short Circuit via Accumulated Current
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Solution Overview
Problem
Existing battery systems with serially and parallelly connected cells face challenges in detecting internal short circuits, particularly small ones, which can lead to heat generation and system deterioration, making it difficult to ensure safe charging and discharging operations.
Innovation Solution
A battery system with a detecting portion that monitors voltage and current of parallel battery units, calculates accumulated current values, and compares these with stored reference values to determine if an internal short circuit occurs, allowing for reliable detection of small short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery cells are connected in parallel to increase output current and battery capacity, then the battery system can provide higher power and capacity, but it becomes difficult to detect internal short circuits in individual cells
Solution Approach 1:
The patent segments the battery system into multiple parallel battery units, each containing series-connected battery cells. By monitoring voltage and current at the unit level rather than individual cells, the system can detect abnormalities in specific units while maintaining the parallel configuration for high power output. The detecting portion calculates accumulated current values for each unit and compares them to identify units with internal short circuits.
Solution Approach 2:
The patent implements a feedback mechanism where the detecting portion continuously monitors voltage and current of each parallel battery unit, calculates accumulated current values, and compares them against reference values. When a deviation exceeds a predetermined threshold, the system generates an abnormality determination signal. This closed-loop feedback enables reliable detection of internal short circuits while maintaining the high-capacity parallel battery configuration.
2Reliability
If a very small internal short circuit occurs in a battery cell, then heat generation may occur and system deterioration may progress, but the short circuit current is too small to be detected by conventional methods
Solution Approach 1:
The patent performs preliminary detection by continuously monitoring voltage and current of each parallel battery unit and calculating accumulated current values before significant heat generation or system deterioration occurs. By comparing accumulated current values against reference values and detecting deviations early, the system can identify very small internal short circuits at their inception, enabling preventive action before the short circuit current becomes large enough to cause damage.
Solution Approach 2:
The patent changes the detection parameter from instantaneous current to accumulated current value. By integrating current over time and comparing accumulated values against reference values, the system becomes sensitive to very small short circuit currents that would be undetectable through conventional instantaneous current measurement. This parameter transformation enables detection of incipient faults with extremely small current magnitudes.
3Duration of action of stationary object
If battery cells are used longer to increase battery life, then the battery system can operate for extended periods, but the risk of internal short circuit increases
Solution Approach 1:
The patent implements continuous monitoring of voltage and current in each parallel battery unit throughout the battery's operational life. The detecting portion continuously calculates accumulated current values and compares them against reference values, maintaining constant surveillance for internal short circuits. This continuous detection capability allows the battery system to safely operate for extended periods by immediately identifying and responding to internal short circuits regardless of battery age.
Data Source
AI summary
A battery system includes a battery pack, a detecting portion, a storage portion, and a determining portion. The battery pack includes serially-connected parallel battery units each of which includes battery cells connected in parallel. The detecting portion detects voltage and current of the units, and calculates the accumulated current value of each of the units. The storage portion stores reference voltage values to be associated the accumulated current value of each of the units. The determining portion reads, from the storage portion, one of the reference voltages corresponding to the accumulated value of each of the units, and compares the read reference voltage with the detection voltage of the each of the units. Thus, a battery cell internal short circuit is detected if the difference between the detection voltage and the read reference voltage exceeds a threshold.