Hybrid Vehicle Battery SOC Region Current Control
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Solution Overview
Problem
Secondary batteries in hybrid vehicles degrade easily during charge and discharge cycles, particularly in specific state of charge (SOC) regions, leading to uneven energy balance and reduced lifespan, depending on the battery type and current rate.
Innovation Solution
A control system that includes associated data on degradation degrees across various SOC regions, monitoring data acquisition, SOC estimation, and upper limit current determination to manage charge and discharge rates, ensuring minimal degradation by optimizing current rates based on battery type and SOC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charge and discharge are performed at high current rate without considering SOC region characteristics, then productivity is improved, but battery degradation accelerates
Solution Approach 1:
The patent applies local quality by dividing the battery's SOC range into multiple regions (first SOC region, second SOC region, etc.) with different degradation characteristics. Each region has its own upper limit current value determined based on local degradation data, allowing the system to adapt charge/discharge rates to specific SOC conditions rather than using a uniform current limit across all SOC levels.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the upper limit current value based on the battery's current SOC state. The control system continuously monitors SOC and retrieves the appropriate upper limit current from stored degradation data, enabling real-time adaptation of charge/discharge rates to current battery conditions, transforming a static current limit into a dynamic one.
2Reliability
If upper limit current value is determined based on SOC region and degradation data, then battery reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-storing degradation data and upper limit current values for multiple SOC regions before actual operation. The control system has already organized the complex degradation characteristics into structured data tables associated with specific SOC ranges, so that during operation, the system only needs to query the appropriate pre-calculated values based on current SOC, avoiding complex real-time calculations.
Solution Approach 2:
The control system implements self-service by automatically determining the upper limit current value based on the battery's own SOC state and the stored degradation data specific to that battery type. The system uses the battery's inherent characteristics (encoded in the degradation data) to self-regulate its operation, reducing the need for external intervention or complex manual control strategies.
Data Source
AI summary
Degradation degree table is a degradation degree table that describes a degradation degree of a secondary battery when the secondary battery is charged or discharged at a prescribed current rate with prescribed frequency. Degradation degree table describes the degradation degree in each of a plurality of state of charge (SOC) regions obtained through division of an SOC range of the secondary battery into the plurality of regions. Upper limit current determining part determines an upper limit current value to be used as a current rate at a time of charge or discharge, based on an estimated SOC and a target degradation degree with reference to degradation degree table.