Battery Safety Index Estimation Under Temperature Change
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Solution Overview
Problem
Existing methods lack effective real-time safety evaluation for nonaqueous electrolyte secondary batteries, such as lithium-ion batteries, which are restricted from being carried on aircraft due to fire risks, but these restrictions impair user convenience, and there is a need for a method to assess their safety accurately.
Innovation Solution
A battery safety evaluation apparatus that includes a battery state estimator, a calorific value estimator, and a safety index calculator, which evaluates the safety of secondary batteries by estimating their deterioration state and state of charge (SOC) and calculates a safety index based on thermal stability data, allowing for individual handling of batteries according to their safety status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonaqueous electrolyte secondary batteries are restricted from being carried in aircraft, then safety risks are reduced, but user convenience deteriorates
Solution Approach 1:
The invention changes the parameter of battery safety assessment from a static restricted/non-restricted binary state to a dynamic continuous safety index value. By calculating real-time safety indices based on temperature, charge state, and deterioration level, the system enables flexible decision-making about battery transport, allowing safe batteries to be carried while restricting only those that pose actual risks.
2Ease of operation
If real-time safety evaluation methods are developed, then user convenience is improved by lifting restrictions, but measurement precision requirements increase
Solution Approach 1:
The invention introduces a safety index as an intermediary parameter that synthesizes multiple measurement data points (temperature, charge state, deterioration level) into a single comprehensive safety assessment. This intermediary value simplifies the complex relationship between multiple battery parameters and safety outcomes, enabling practical real-time evaluation without requiring direct measurement of all underlying factors with extreme precision.
Solution Approach 2:
The invention replaces direct physical measurement of battery safety (which would require complex intrusive sensors) with a computational model that calculates safety indices from easily measurable parameters like temperature and voltage. This substitution of mechanical/physical measurement systems with computational assessment reduces measurement precision requirements while maintaining evaluation accuracy.
3Measurement precision
If comprehensive safety evaluation systems are implemented, then safety assessment accuracy is improved, but device complexity increases
Solution Approach 1:
The invention segments the safety evaluation system into three independent functional modules: temperature detection unit, charge state estimation unit, and safety index calculation unit. Each module performs a specific function using simple algorithms, avoiding the need for a single complex integrated system. This segmentation reduces overall device complexity while maintaining comprehensive safety assessment accuracy.
Data Source
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AI summary
An apparatus which is an arrangement of the present invention includes a first estimator, a second estimator and a calculator, and evaluates the present safety of a battery. The first estimator estimates a present deterioration state and a present SOC of the battery. The second estimator estimates, on the basis of first reference data, a calorific value of the battery in an occasion when an external temperature changes. The first reference data is selected as corresponding to the first battery from a plurality of reference data at least indicating relationship between a calorific value of a secondary battery and an external temperature on the basis of the estimated deterioration state and SOC. The calculator calculates, on the basis of the calorific value of the battery, a safety index regarding a temperature of the battery in the occasion when the external temperature changes.