Battery SOH Estimation from OCV-Electrode Profile Matching
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Solution Overview
Problem
Conventional methods for diagnosing the state of a battery require low-rate charging and discharging, which are time-consuming and limit the use of the battery, making it difficult to accurately assess the State of Health (SOH) efficiently.
Innovation Solution
An apparatus and method that estimates SOH using Open Circuit Voltage (OCV) profiles, adjusting positive and negative electrode profiles to generate an adjusted profile that reflects the current state of the battery, allowing for quick and unrestricted battery use during diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If low-rate charging and discharging is used to diagnose battery state, then measurement precision is improved, but loss of time increases significantly
Solution Approach 1:
The patent changes the measurement parameter from low-rate charging/discharging current to open-circuit voltage (OCV). By measuring OCV at different states of charge and constructing an OCV-SOC profile, the system achieves accurate battery state diagnosis without requiring time-consuming low-rate charging/discharging processes. The OCV measurements are taken at regular intervals during normal charging/discharging operations, dramatically reducing diagnosis time while maintaining measurement precision.
2Manufacturing precision
If low-rate charging and discharging is used to obtain accurate battery profile, then manufacturing precision is improved, but productivity decreases due to restricted battery use
Solution Approach 1:
The patent enables the battery system to diagnose its own state using OCV measurements taken during normal operation. The control unit continuously monitors OCV and constructs the OCV-SOC profile without requiring external low-rate charging/discharging equipment or processes. This self-service approach maintains accurate battery profiling while allowing the battery to be used at full capacity for its intended purposes, thereby preserving productivity.
3Reliability
If conventional low-rate charging and discharging is used for SOH estimation, then reliability of SOH estimation is improved, but ease of operation deteriorates due to operational restrictions
Solution Approach 1:
The patent performs preliminary OCV measurements at multiple states of charge during normal battery operation to construct the OCV-SOC profile in advance. This preliminary action captures the battery's characteristic curve without requiring subsequent low-rate charging/discharging for SOH estimation. The system stores this profile and uses it for rapid SOH calculation, maintaining reliability while eliminating operational restrictions.
Data Source
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AI summary
An apparatus for estimating a SOH according to one aspect of the present disclosure may include a profile obtaining unit configured to obtain an OCV profile for a plurality of OCVs of a battery measured at different time points; a profile correcting unit configured to generate an adjusted positive electrode profile and an adjusted negative electrode profile by adjusting a preset criterion positive electrode profile and a preset criterion negative electrode profile to correspond to the OCV profile; and a control unit configured to extract a diagnosis factor for the battery from the adjusted positive electrode profile or the adjusted negative electrode profile, and estimate a capacity SOH of the battery based on the extracted diagnosis factor.