Traction Battery Array SOC Estimation for Mixed-Age Cell Packs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrified vehicle traction batteries face challenges in managing age differences between arrays of battery cells, leading to inconsistencies in state-of-charge (SOC), state-of-health (SOH), and state-of-power (SOP), which affect overall battery performance and efficiency.
Innovation Solution
Implementing a control strategy that utilizes bar-delta filters to model and estimate the SOC, SOH, and SOP of individual arrays within the traction battery, considering age differences, and adjust power limits accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If arrays of battery cells are replaced individually for serviceability, then ease of repair is improved, but manufacturing precision deteriorates due to age differences between arrays
Solution Approach 1:
The battery pack is divided into multiple arrays of battery cells, each with its own state estimator. This segmentation allows individual arrays to be replaced independently for serviceability while maintaining accurate state estimation for each array and the overall battery pack.
Solution Approach 2:
Each array is equipped with dedicated state estimators that consider the specific age and characteristics of that array. This local quality approach ensures that state estimation accuracy is maintained for each individual array despite age differences between arrays.
2Measurement precision
If individual array state estimation is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The state estimation function is segmented into multiple independent estimators, each responsible for a specific array. This segmentation improves measurement precision for each array while organizing the complexity in a manageable, modular structure.
Solution Approach 2:
The state estimators from multiple arrays are combined to determine the overall battery pack state. This merging approach maintains high measurement precision while managing device complexity through systematic integration of individual array estimates.
Data Source
AI summary
A system includes a traction battery and a controller. The traction battery includes first and second arrays of battery cells. The controller is programmed to implement first and second filters, such as first and second bar-delta filters, configured to respectively generate output indicative of a state-of-charge (SOC) of the first and second arrays from models of the first and second arrays. The controller is further programmed to charge and/or discharge the traction battery according to power limits defined by the SOC of the first and second arrays.