Battery State Estimation via Discharge Voltage Difference Analysis
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Solution Overview
Problem
Existing methods for detecting abnormal battery conditions in Li-ion batteries are inefficient, often requiring additional operations and short measurement intervals, which can disrupt normal battery operation and fail to accurately assess battery health in real-time.
Innovation Solution
A state estimation method that calculates discharge voltage difference data, determines a specific interval, and uses aging factor data to estimate capacity loss, allowing for the detection of abnormal battery conditions without interrupting normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional operations are performed to calculate internal resistance by adding a load, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent extracts only the necessary measurement data (voltage and current during normal discharge) from the complex internal resistance measurement process, eliminating the need for additional load operations while maintaining measurement capability through selective data utilization
Solution Approach 2:
The battery system performs self-diagnosis using its own operating data (voltage and current during normal discharge) without requiring external intervention or additional testing equipment, enabling autonomous health assessment
2Measurement precision
If short measurement intervals are used to calculate differential change rate, then measurement precision is improved, but productivity deteriorates due to operational interruption
Solution Approach 1:
The patent maintains continuous battery discharge operation without interruption, using data collected during normal use to perform health assessment, thereby eliminating downtime while maintaining measurement accuracy through continuous monitoring
Solution Approach 2:
The system continuously collects and stores voltage and current data during normal operation in advance, preparing the necessary measurement information beforehand so that health assessment can be performed without requiring additional measurement time or operational interruption
3Measurement precision
If multiple operations are required to calculate internal resistance at different time instants, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent merges multiple measurement operations into a single continuous discharge process, collecting voltage and current data at different time instants simultaneously during one uninterrupted discharge, thereby eliminating the need for separate measurement operations and reducing total measurement time
Data Source
AI summary
This disclosure provides a state estimation method and a battery pack. The method includes: obtaining aging factor data, predetermined discharge data and predetermined capacity loss changing data; recording measured discharge data of a to-be-measured battery; calculating to obtain discharge voltage difference data according to the predetermined discharge data and the measured discharge data; determining a specific interval Sa according to the discharge voltage difference data, and obtaining a voltage difference statistical value ΔV2,Stats in the specific interval Sa; calculating an estimation capacity loss ΔQD of the to-be-measured battery according to the aging factor data and the voltage difference statistical value ΔV2,Stats; and determining whether the to-be-measured battery is abnormal or not according to the predetermined capacity loss changing data and the estimation capacity loss ΔQD.