Battery Control Device Correcting SOC-OCV Curve for Degradation
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Solution Overview
Problem
Existing battery control devices struggle to accurately calculate state of charge (SOC) after the relationship between SOC and open circuit voltage (OCV) changes due to battery deterioration, as they do not effectively reflect these changes in their calculations.
Innovation Solution
A battery control device that includes a controller capable of correcting the SOC-OCV characteristic based on acquired pairs of state of charge and open circuit voltage, allowing for accurate SOC calculation even after battery deterioration, by using a storage unit to store relationships between SOC and OCV and correcting the SOC-OCV curve accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the battery is used over time, then the battery provides continuous operation, but the relationship between SOC and OCV changes due to deterioration
Solution Approach 1:
The patent applies dynamics by making the SOC-OCV characteristic correction table updateable over time. The system dynamically adjusts the correction values based on accumulated operating hours, transitioning from a static to a dynamic characteristic table that adapts to battery deterioration, thereby maintaining accurate SOC calculation throughout the battery's operational life
Solution Approach 2:
The patent changes the parameters of the SOC-OCV relationship by introducing correction values that are applied to the standard SOC-OCV table. These correction values are determined based on operating hours and are used to adjust the open circuit voltage values, effectively changing the parameters to compensate for battery deterioration effects
2Measurement precision
If the SOC-OCV characteristic is corrected based on operating hours, then the measurement precision of SOC is improved, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction values in a correction table before actual use. The correction table is prepared in advance with correction values corresponding to different operating hour ranges, so that during operation, the system only needs to lookup and apply the appropriate correction values without performing complex real-time calculations
Solution Approach 2:
The patent introduces an intermediary element - the correction table - that mediates between the standard SOC-OCV relationship and the deteriorated battery characteristics. This correction table acts as a bridge, containing pre-computed adjustment values that simplify the correction process while maintaining high measurement precision
Data Source
AI summary
Provided is a battery control device that can accurately detect a state of charge even if characteristics relating to the state of charge change as a result of battery degradation. This battery control device is provided with map data describing the correspondence relationship between an open-circuit voltage and a state of charge of the battery and outputs different state-of-charge values for the same open-circuit voltage according to the amount of elapsed time.