Battery Capacity Estimation Using Charging-Pause Impedance
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Solution Overview
Problem
Existing battery capacity calculation methods require complete discharge of the battery, resulting in low calculation frequency and inefficient battery health monitoring.
Innovation Solution
A battery capacity calculation device and method that calculates full charge capacity at a high frequency by acquiring voltage and current values during charge, calculating impedance growth, and using the number of cycles and time to determine the full charge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete discharge of the battery is required for capacity calculation, then measurement accuracy is improved, but calculation frequency decreases
Solution Approach 1:
The patent applies partial action by calculating full charge capacity without requiring complete battery discharge. Instead of performing the full discharge cycle traditionally needed for accurate capacity measurement, the system uses impedance measurements taken during normal charging operations to estimate capacity. This partial measurement approach maintains sufficient accuracy while enabling frequent calculations during regular charging events.
Solution Approach 2:
The patent performs preliminary impedance measurements during the charging process before complete discharge is needed. By measuring impedance at various states of charge during normal charging operations, the system prepares capacity calculation data in advance, allowing frequent capacity assessments without waiting for complete discharge cycles.
2Measurement precision
If impedance measurement is performed during charging pause, then measurement accuracy is improved, but charging time increases
Solution Approach 1:
The patent uses a brief charging pause for impedance measurement rather than requiring a complete charge cycle interruption. The measurement is performed for a short duration during the charging process, obtaining sufficient impedance data without significantly extending total charging time. This partial interruption balances measurement accuracy with time efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables frequent calculation of full charge capacity without complete discharge, improving battery health monitoring and timely replacement notifications.
Implementation Method 1
calculate an impedance value of the battery by using the first voltage value, the second voltage value, and the charge current value
Data Source
AI summary
A battery capacity calculation device includes: a controller configured to: acquire, while a battery is in charge, a first voltage value and a charge current value of the battery, acquire, while charging of the battery is in pause, a second voltage value of the battery, calculate an impedance value of the battery by using the first voltage value, the second voltage value, and the charge current value, calculate an impedance growth that is a ratio of the impedance value to an initial impedance value recorded in a memory in advance, acquire the number of cycles of the battery, acquire time until a temperature of the battery falls within a predetermined temperature range and an output voltage value of the battery falls within a predetermined voltage range, and calculate a full charge capacity of the battery by using the number of cycles, the impedance growth, and the time.