Battery SOC Estimation via OCV Correlation and Reference Tables
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Solution Overview
Problem
The existing technologies face challenges in efficiently estimating the correlation information between the State Of Charge (SOC) and Open Circuit Voltage (OCV) of electric storage sections, particularly in systems with multiple storage batteries having different characteristics, which affects the precise control and degradation management of these batteries.
Innovation Solution
The proposed solution involves a power storage device with two storage batteries of different characteristics, where a battery ECU performs charge/discharge control to determine the SOC-OCV curve by plotting coordinates on a two-dimensional plane and selecting the most probable curve from reference data, allowing for precise estimation of SOC based on OCV measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If charge/discharge control is performed between multiple storage batteries with different characteristics, then SOC-OCV correlation information can be obtained, but the estimation efficiency and accuracy are insufficient
Solution Approach 1:
The system performs preliminary charge/discharge control to collect SOC-OCV data points before actual operation, storing them as reference information. This preliminary data collection enables accurate SOC estimation during normal operation without requiring repeated charge/discharge cycles, thus resolving the contradiction between accuracy and efficiency.
Solution Approach 2:
The patent creates a reference SOC-OCV curve by copying measured data points into a predetermined table structure. During operation, the system copies the current OCV from measurement and retrieves the corresponding SOC from the reference table, eliminating the need for real-time complex calculations and improving estimation efficiency while maintaining accuracy.
2Adaptability or versatility
If multiple storage batteries with different characteristics are used, then power supply flexibility is improved, but determining accurate SOC-OCV correlation becomes more difficult
Solution Approach 1:
The patent segments the SOC-OCV characteristics into individual curves for each storage battery type. The control section identifies which battery is being measured and selects the corresponding segmented reference table, allowing accurate correlation determination for each battery type while maintaining the flexibility to use multiple battery types with different characteristics.
Solution Approach 2:
The system applies local quality by creating distinct SOC-OCV reference tables tailored to each storage battery's specific characteristics. Each battery type has its own localized correlation data, ensuring high measurement precision for that specific battery while the overall system maintains adaptability to handle multiple battery types.
Data Source
AI summary
A power supply apparatus includes a first and second electric storage sections, a charge/discharge circuit performing charge/discharge between the first and second storage sections, and a control section controlling the charge/discharge circuit. The control section sets at least one of the first and second storage sections as a target storage section, acquires a target SOC and a target OCV which are respectively a charge rate and an open-end voltage of the target storage section, collects, by using charge transfer between the first and second storage sections, data including the target SOC and the target OCV in an order based on a collection rule determined by collected data and the target SOC, the collected data being an aggregation of the data which is collected, and estimates correlation information between an SOC and an OCV of the target storage section based on a plurality of the data.