Battery Pack SOH Estimation via Weighted Average
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery management systems face challenges in accurately estimating the state of health (SOH) of battery packs, leading to potential safety issues and reduced cycle life due to inaccuracy in capacity estimation.
Innovation Solution
A method for estimating the SOH of battery packs by determining the target SOH value using a weighted average of initial and final SOH values, considering factors like resting time, battery temperature, and open circuit voltage, and adjusting for capacity changes through a relational expression and moving average filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional SOH estimation methods are used, then the estimation process is simple, but the SOH value estimation accuracy is poor
Solution Approach 1:
The patent divides the SOH estimation process into multiple segments: determining initial SOH value, determining final SOH value, calculating charge capacity, and applying weighted average. This segmentation allows each component to be optimized independently while maintaining overall accuracy.
Solution Approach 2:
The patent introduces dynamic adjustment through weighted average calculation, where weights are assigned to initial and final SOH values based on their reliability. This dynamic approach adapts the estimation process to different operating conditions, improving accuracy without excessive complexity.
2Measurement precision
If multiple parameters are considered for SOH estimation, then the estimation accuracy improves, but the calculation complexity increases
Solution Approach 1:
The patent performs preliminary determination of initial SOH value and final SOH value before the main estimation calculation. This preliminary action organizes the complex parameters into structured components, making the subsequent weighted average calculation more manageable and efficient.
Solution Approach 2:
The patent incorporates feedback mechanisms by using charge capacity information to adjust the SOH estimation. The system continuously monitors charge capacity and uses this feedback to refine the SOH value through the weighted average calculation, improving precision while maintaining computational efficiency.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The disclosure provides a state-of-health (SOH) estimation method of a battery pack including the following steps. A corresponding total charge capacity of a battery pack from completion of a first charge to completion of a current charge is determined by accumulating a charge capacity of each charge. Afterwards, a target SOH value may be determined according to the total charge capacity and a predetermined capacity change threshold to characterize the influence of the cyclic charge of the battery pack on its attenuation.