Battery Life Estimation via Discharge Capacity Variation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for estimating the remaining life of nickel metal hydride batteries are ineffective as significant changes in voltage or resistance values do not occur until deterioration is advanced, making it difficult to predict battery life.
Innovation Solution
A method involving discharging an assembled battery to a State Of Charge (SOC) of 40% or 0% to measure discharge capacity variations among battery blocks, calculating capacity differences, and determining remaining life based on these variations, allowing for accurate estimation of battery life even when changes in voltage or resistance are minimal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voltage or resistance measurement methods are used to estimate battery life, then the measurement process is simple, but the measurement precision is insufficient because significant changes do not occur until deterioration is advanced
Solution Approach 1:
The patent changes the measurement parameter from voltage or resistance to discharge capacity. By measuring the discharge capacity of each battery block when discharged to a predetermined SOC (State of Charge), the method detects capacity differences that indicate deterioration, providing accurate remaining life estimation without requiring complex additional equipment.
2Measurement precision
If the assembled battery is discharged to measure discharge capacity of each battery block, then the remaining life estimation accuracy is improved, but the time and energy consumption increases
Solution Approach 1:
The patent applies partial action by discharging the assembled battery only to a predetermined SOC (e.g., 20% or 30%) rather than complete discharge. This partial discharge is sufficient to reveal capacity differences among battery blocks while minimizing time and energy consumption compared to full discharge methods.
3Measurement precision
If discharge capacity measurement is performed to detect capacity differences among battery blocks, then the remaining life estimation accuracy is improved, but the charge and discharge control complexity increases
Solution Approach 1:
The patent implements feedback control by measuring the discharge capacity of each battery block, calculating capacity differences, and using this information to determine remaining life. The system provides feedback on the deterioration state of individual battery blocks, enabling accurate remaining life estimation without requiring complex additional control mechanisms.
Data Source
AI summary
A method includes discharging an assembled battery (10) formed of a plurality of batteries until a state of charge (SOC) of the assembled battery becomes smaller or equal to a lower limit of a predetermined normal use range used in charge and discharge control of the assembled battery, measuring the discharge capacity of each of a plurality of battery blocks in the discharge of the assembled battery, the plurality of batteries being divided into the plurality of battery blocks, calculating the capacity difference in the discharge capacity among the plurality of battery blocks, and determining the remaining life of the battery block or the assembled battery based on the calculated capacity difference.