Battery Swelling Risk Estimation Using Voltage Current Data
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Solution Overview
Problem
Current battery safety evaluation methods fail to detect precursory phenomena of battery swelling, such as rapid expansion due to irreversible thickness increase, which can lead to cell firing, making complete prevention of cell fires difficult.
Innovation Solution
A battery safety evaluation apparatus that estimates inner state parameters and calculates a battery swelling index based on voltage and current data during charging or discharging, using reference data to evaluate the risk of battery swelling and ensure safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional battery safety evaluation methods are used, then the evaluation process is simple, but the ability to detect precursory phenomena of battery swelling is insufficient
Solution Approach 1:
The patent applies preliminary action by estimating inner state parameters (such as electrode thickness, gas generation amount, and deterioration products) before actual battery swelling occurs. This allows detection of precursory phenomena early in the deterioration process, enabling preventive measures to be taken before rapid expansion and cell firing happen. The evaluation apparatus continuously monitors and estimates these parameters during battery use rather than waiting for visible swelling.
Solution Approach 2:
The patent replaces mechanical detection methods (such as physical measurement of battery dimensions) with electrical measurement and estimation techniques. By using voltage and current data during charge/discharge cycles, the system estimates inner state parameters through mathematical models and algorithms, substituting direct mechanical measurement with indirect electrical characterization that provides more precise early detection capability.
2Reliability
If nondestructive examination methods are implemented to detect precursory phenomena, then battery safety evaluation capability is improved, but the complexity of the evaluation apparatus increases
Solution Approach 1:
The patent applies universality by designing an evaluation apparatus that performs multiple functions using a single integrated system. The apparatus simultaneously estimates multiple inner state parameters (electrode thickness, gas generation, deterioration products) and evaluates different aspects of battery safety from the same voltage and current measurements, rather than requiring separate dedicated devices for each measurement type.
Solution Approach 2:
The patent uses voltage and current measurements during charge/discharge as intermediary parameters to indirectly estimate the actual inner state parameters that are difficult to measure directly. These electrical measurements serve as mediators that provide information about electrode thickness, gas generation, and deterioration products without requiring direct physical access to or manipulation of the battery's internal structure.
3Measurement precision
If detailed inner state parameter estimation is performed, then detection accuracy of precursory phenomena is improved, but calculation complexity and data processing requirements increase
Solution Approach 1:
The patent applies partial action by focusing estimation efforts on the most critical inner state parameters that are most indicative of precursory swelling phenomena (such as electrode thickness changes and gas generation amounts). Rather than attempting to measure or calculate all possible battery parameters, the system concentrates computational resources on the key parameters that provide the highest detection accuracy for safety evaluation.
Solution Approach 2:
The patent implements feedback mechanisms where the estimated inner state parameters are continuously updated based on new voltage and current measurements. The system uses the estimated parameters to predict future battery behavior and compares these predictions with actual measurements, adjusting the estimation models accordingly to improve accuracy over time while managing computational complexity through iterative refinement.
Data Source
AI summary
A battery safety evaluation apparatus as an aspect of the present invention includes an estimator, a calculator, and an evaluator. The estimator estimates an estimation value of an inner state parameter of a battery to be evaluated on the basis of data of its voltage and current measured in charging or discharging it. The calculator calculates an index regarding swelling risk of the battery on the basis of first reference data. The evaluator evaluates, on the basis of the index, a battery swelling risk of the battery to evaluate safety of the battery. The battery is a secondary battery. The first reference data is reference data considered to correspond to the battery from the reference data on the basis of estimation value. The reference data indicates at least one of relationships between a positive electrode capacity, a negative electrode capacity and an SOC deviation of a secondary battery.