Battery Deterioration Calculation with Preliminary Baseline Correction
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Solution Overview
Problem
Existing methods for calculating the deterioration state of electric cells, such as batteries, face accuracy issues when the load is not used for a long period, leading to low calculation accuracy.
Innovation Solution
A deterioration-state calculation system and method that includes a charge controller with sensors for voltage, current, and temperature, which calculates the state of health (SOH) of the battery by integrating charge-discharge currents and open-circuit voltage, while correcting for polarization and neglect time to enhance calculation reliability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the change amounts of SOC and Ah are calculated using the conventional method between first and second time points, then the fully-charged capacity can be calculated, but the calculation accuracy of deterioration state becomes low when the load is not used for a long period of time
Solution Approach 1:
The patent applies preliminary action by calculating the change amount of state of charge (ΔSOC) and change amount of charge-discharge (ΔAh) during a preliminary period when the load is not used for a long time, before the actual deterioration state calculation is performed. This preliminary calculation ensures that accurate baseline data is obtained even when the load remains inactive for extended periods, thereby maintaining high calculation accuracy of the deterioration state.
2Stability of the object's composition
If the load is not used for a long period of time, then the battery can maintain stable operation, but the change amounts (ΔSOC and ΔAh) cannot be calculated appropriately leading to low calculation accuracy
Solution Approach 1:
The patent performs preliminary calculations of ΔSOC and ΔAh during a specific period when the load is not used, capturing the battery's natural state changes without load interference. This preliminary action allows the system to establish accurate baseline measurements while the battery operates stably, ensuring that subsequent deterioration state calculations maintain high precision even when the load remains inactive for long periods.
Data Source
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AI summary
A deterioration-state calculation method for calculating a deterioration state of a battery by using a processor for managing a state of the battery comprising: detecting current of the battery and voltage of the battery by using a sensor; calculating a charge state of the battery based on a detected value of the sensor; calculating a first deterioration state of the battery for each predetermined period based on an elapsed time from the time use of the battery is started and an amount of charge-discharge of the battery; calculating a second deterioration state of the battery based on a change amount in the charge state of the battery and a change amount of current of the battery; executing calculation step for calculating the second deterioration state for a plurality of times within the predetermined period; calculating reliability of calculation of the second deterioration state for each of a plurality of the second deterioration states based on the detected value; calculating a correction value of the deterioration state based on the second deterioration state with the reliability of the predetermined reliability or higher; and calculating the deterioration state by correcting the first deterioration state by the correction value.