Battery Degradation Estimation via Charge Capacity Variation Mapping
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Solution Overview
Problem
Current methods fail to accurately estimate the degradation of high-voltage batteries in electric vehicles and plug-in hybrid electric vehicles, leading to inaccurate State Of Charge (SOC) readings and unstable vehicle performance.
Innovation Solution
A method that involves obtaining and comparing variations in charge capacity with respect to voltage during slow charging, using a base map of charge capacity variations at different degradation levels to determine the relevant degradation degree of the battery, while measuring current, voltage, and temperature to ensure accurate SOC representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SOC estimation methods are used, then the system is simple to operate, but the measurement precision of battery degradation is insufficient
Solution Approach 1:
The patent applies preliminary action by pre-establishing a base map containing charge capacity variation data at multiple degradation levels before actual use. During operation, the system only needs to compare current measurements against this pre-prepared reference data, avoiding complex real-time degradation calculations and reducing computational complexity while maintaining high precision.
Solution Approach 2:
The patent uses copying by creating a base map that replicates the charge capacity characteristics of batteries at different degradation levels. This base map serves as a reference copy that can be repeatedly compared against actual battery measurements, enabling accurate degradation assessment without requiring complex analytical models for each measurement.
2Reliability
If battery degradation is not monitored, then the system operates continuously, but the reliability of vehicle performance deteriorates over time
Solution Approach 1:
The patent implements continuity of useful action by enabling real-time degradation monitoring during normal battery charging operations. The system continuously compares charge capacity variations against the base map without interrupting vehicle operation, ensuring reliable performance assessment while minimizing time loss through seamless integration into existing charging processes.
3Measurement precision
If accurate degradation estimation is implemented, then SOC accuracy improves, but the ease of operation decreases due to additional measurements
Solution Approach 1:
The patent applies universality by designing a degradation determination system that uses the same charge capacity measurements already taken for SOC estimation. The base map comparison mechanism serves multiple functions: it assesses degradation levels while utilizing existing charging data, eliminating the need for separate dedicated degradation testing procedures and maintaining operational simplicity.
Data Source
AI summary
Disclosed herein is a technique for determining degradation of a high-voltage battery of a vehicle. More specifically, variations in charge capacity with respect to a predetermined variation in voltage of a high-voltage battery that is currently being slowly charged are obtained depending on degradation degrees of the high-voltage battery. A vehicle equipped with a high-voltage battery having a specification identical to those of the high-voltage battery is used to acquire a charge capacity and a voltage of the high-voltage battery that is currently being slowly charged. A variation in charge capacity with respect to the predetermined variation in voltage is calculated from the charge capacity and the voltage. The variation in charge capacity with respect to the predetermined variation in voltage is compared with the variations in charge capacity with respect to the predetermined variation in voltage depending on the degradation degrees, thus determining a relevant degradation degree.