Application-Independent Battery Cycle Life Testing
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Solution Overview
Problem
Existing battery test procedures are application-dependent, time-consuming, and expensive, making it difficult to determine the useful life span of batteries for various usage scenarios, as they often take over a year to complete and provide results that are not easily convertible across different applications.
Innovation Solution
The implementation of application-independent map-based cycle life testing for battery cells, which involves selecting a depth of discharge and performing repeated discharge/charge cycles across a range of discharge depths and charge/discharge current levels, generating a test map to model diverse usage conditions, and dynamically varying test parameters using feedback control loops based on battery voltage drift monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If application-dependent test procedures are used to accurately characterize battery life for specific drive cycles, then measurement precision is improved, but testing time increases significantly (taking a year or more) and device complexity increases
Solution Approach 1:
The patent segments the continuous range of drive cycles into discrete clusters representing different application types (e.g., HEV, PHEV, BEV, grid storage). Instead of testing each specific drive cycle individually, the method creates representative test profiles for each cluster, reducing the number of tests required while maintaining characterization accuracy for applications within that cluster.
Solution Approach 2:
The patent develops a universal testing framework that can characterize batteries for multiple application types using a single set of standardized test procedures. The application-independent test methods produce results that can be converted to estimate battery life across different drive cycles and usage scenarios, eliminating the need for separate application-specific test programs.
2Measurement precision
If application-specific test procedures are implemented to obtain accurate battery life data for particular usage scenarios, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates universal test procedures that can be applied across different battery types and application scenarios. The standardized testing protocols and conversion algorithms provide a unified approach that simplifies the testing infrastructure while maintaining the ability to predict battery life for various applications including vehicle types and grid storage scenarios.
Solution Approach 2:
The patent transforms the testing approach by changing from application-specific parameters to application-independent parameters. Instead of designing tests around specific drive cycle characteristics, the method uses fundamental battery degradation parameters that can be measured once and then converted to predict performance across different applications, reducing test complexity.
3Adaptability or versatility
If comprehensive application-specific testing is performed to characterize battery performance across different drive cycles, then adaptability to various applications is improved, but testing time and cost increase significantly
Solution Approach 1:
The patent develops universal testing methods that can characterize batteries for multiple applications simultaneously. The application-independent test results can be converted to estimate battery life for various drive cycles and usage scenarios, providing broad application coverage without requiring separate test programs for each application type.
Solution Approach 2:
The patent performs preliminary characterization tests that capture fundamental battery degradation behavior. These preliminary results are then used as the basis for converting to application-specific predictions, eliminating the need to perform comprehensive long-duration testing for each application while still providing adaptability across different usage scenarios.
Data Source
AI summary
A method and system for application independent map-based cycle life testing of battery cells is provided. A target depth of discharge (DOD) and a charge/discharge current level is selected for the battery test. The battery is discharged to the target DOD. The battery is cycled within the DOD range one or more times, wherein the cycling comprises a charge pulse and a discharge pulse at the selected current levels. A reference performance test (RPT) is performed on the battery, wherein the RPT comprises a static capacity test and a dynamic power test. The cycling and RPT testing are repeated until an end of test condition is detected.