Battery Pack Operating Limits Based on Aging State Detection
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Solution Overview
Problem
Existing battery management systems fail to accurately detect internal cell defects in battery packs, leading to accelerated aging and sudden failures, especially in aged cells, which can lead to dangerous situations due to undefined operating limits and thermal runaway.
Innovation Solution
A method for operating a battery pack that determines a current intermediate characteristic value, such as energy throughput (ETP), to assess the aging state, compares it with predetermined values for end-of-life (EoL) and end-of-safe-operation (EoS), and adjusts operational limits to prevent overloading and extend the battery's safe operation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery pack operates without adjusted limits, then productivity is maintained, but reliability deteriorates due to undetected internal defects and accelerated aging
Solution Approach 1:
The patent implements dynamic adjustment of operational limits based on the battery's aging state. The BMS continuously monitors an intermediate characteristic value and compares it against predetermined thresholds, automatically modifying operational parameters (such as current or power limits) as the battery ages. This dynamic approach allows the system to maintain safety by reducing limits when aging indicators are reached, while preserving maximum productivity when the battery is in good condition.
2Measurement precision
If traditional BMS monitoring is used, then ease of operation is maintained, but measurement precision deteriorates due to inability to detect internal cell defects
Solution Approach 1:
The patent introduces an intermediate characteristic value as a mediator between direct cell monitoring and overall battery health assessment. Instead of directly measuring complex internal cell defects, the BMS monitors this intermediate parameter (which could be derived from voltage, current, temperature, or other measurable quantities) that correlates with aging and internal defects. This intermediary approach enables precise aging state detection without requiring direct measurement of every internal cell condition, thus balancing measurement precision with system complexity.
3Duration of action of moving object
If operational limits are not adjusted, then productivity is maintained, but loss of time increases due to sudden failures and thermal runaway events
Solution Approach 1:
The patent applies preliminary action by proactively adjusting operational limits before critical failures occur. The BMS continuously monitors the intermediate characteristic value and compares it against predetermined thresholds that indicate approaching aging limits. When these thresholds are reached, the system preemptively modifies operational parameters to prevent further degradation, thermal runaway, or sudden failures. This preliminary intervention extends the battery's safe service life while maintaining optimal power output within the adjusted limits.
Data Source
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AI summary
The present disclosure refers to a method for operating a battery pack, is provided. Thereby a current intermediate characteristic value characterizing an aging state degree of the battery pack is determined based on detected and/or obtained condition measurement signal. Afterwards, a comparison of the current intermediate characteristic value and a first predetermined value of the intermediate characteristic value is performed, wherein the first predetermined value includes a value of the intermediate characteristic value at which a predefined value of the aging state degree is undercut. Further, an operational limit for the battery pack is adjusted based on the comparison. The invention further relates to a battery system including a battery pack, the battery system being configured for performing the disclosed method.