Battery Life Estimation via Segmented Degradation Analysis
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Solution Overview
Problem
There is a need for a reliable and accurate method to estimate the remaining useful life of automotive propulsion batteries in electric and hybrid electric vehicles, as regulatory authorities require indication of battery end-of-life, typically when capacity degrades to 75% of its initial value, to ensure timely replacement within warranty periods.
Innovation Solution
A method calculates the total usable capacity of the battery based on cycling and aging, with two components of degradation: one from driving throughput and the other from aging, to estimate remaining life, providing an indication to the user.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a simple battery life estimation method is used, then the device complexity is reduced, but the measurement precision of battery remaining life is insufficient
Solution Approach 1:
The battery degradation process is segmented into two distinct components: cycling degradation (first component) and aging degradation (second component). The system separately calculates each component based on different parameters - cycling degradation from driving throughput and aging degradation from time-based deterioration models. This segmentation allows for more precise overall degradation estimation while maintaining manageable computational complexity for each individual component.
2Reliability
If battery life estimation accounts for both cycling and aging, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The reliability is improved by segmenting the degradation into cycling and aging components that can be calculated independently and then summed. This approach maintains reliability while controlling complexity by avoiding the need for a single complex unified model.
Solution Approach 2:
The system uses readily available operational data from the battery management system (driving throughput, cycle counts, time stamps) to calculate degradation components without requiring external testing or specialized equipment. The battery essentially serves its own diagnostic function by providing the data needed for its own life estimation.
3Measurement precision
If the battery degradation is calculated with multiple components, then the measurement precision is improved, but the ease of operation is reduced
Solution Approach 1:
The system automatically performs the multi-component degradation calculation without requiring user intervention. The battery management system continuously monitors operational parameters and automatically updates the remaining life estimation, presenting the result to the user as a single unified value rather than requiring the user to understand or input multiple separate parameters.
Solution Approach 2:
The complex multi-component calculation logic is extracted from the user interface and embedded within the battery management system's control unit. The user interacts only with the simplified output (remaining life indication) while the complex degradation component calculations are handled automatically in the background by the control system.
Data Source
AI summary
Methods and systems for estimating remaining life of an automotive propulsion battery are provided. A total usable capacity of the battery is calculated based on cycling the battery. A first component of degradation is calculated based on driving throughput of the battery. A second component of degradation is calculated based on aging of the battery. The total degradation is calculated based on the sum of the first component and the second component of degradation.