Battery Capacity Measurement via Impedance Angular Speed Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery capacity measuring devices face challenges in accurately calculating the capacity retention rate of rechargeable batteries, especially those used in electric vehicles, due to the need for temperature increase and prolonged measurement times, making it impractical for in-use batteries.
Innovation Solution
A battery capacity measuring device and method that measures complex impedance and calculates capacity retention rate using a parameter derived from the ratio of differences in angular speeds and imaginary components of complex impedances, allowing for accurate capacity calculation without requiring temperature increase, thus reducing measurement time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the battery capacity measuring device uses the existing method with temperature increase to 40°C or greater and measurement of impedance in vertical region dc, then the capacity retention rate calculation accuracy is improved, but the measurement time is excessively prolonged and temperature control complexity increases making it impractical for in-use batteries
Solution Approach 1:
The patent changes the measurement parameters by selecting a different frequency range (0.1 Hz to 10 Hz) and temperature range (10°C to 40°C) compared to the prior art. This allows measurement in the diffusion region d rather than vertical region dc, achieving acceptable accuracy without requiring excessive temperature increase or prolonged measurement time
Solution Approach 2:
The patent applies partial action by measuring only at selected frequency points within the diffusion region d (0.1 Hz to 10 Hz) rather than requiring complete coverage of the vertical region dc. This partial measurement approach achieves sufficient accuracy for capacity retention rate calculation while significantly reducing measurement time
2Measurement precision
If the battery capacity measuring device increases temperature to 40°C or greater for measurement, then the impedance measurement accuracy in vertical region dc is improved, but the device complexity and operational difficulty increase
Solution Approach 1:
The patent changes the operating parameters by allowing measurement at lower temperatures (10°C to 40°C) and in the diffusion region d (0.1 Hz to 10 Hz) rather than requiring high temperature (40°C or greater) and vertical region dc measurement. This makes the device easier to operate without sacrificing essential measurement accuracy
Solution Approach 2:
The patent enables the measurement system to automatically identify and measure in the diffusion region d based on the impedance characteristics at different frequencies, without requiring manual temperature control or complex region identification. The system self-adjusts to the appropriate measurement parameters
3Measurement precision
If the battery capacity measuring device measures impedance in vertical region dc at low frequency, then the capacity retention rate accuracy is improved, but the measurement time is excessively prolonged
Solution Approach 1:
The patent changes the frequency measurement parameters by focusing on the diffusion region d (0.1 Hz to 10 Hz) rather than requiring measurement in the vertical region dc at very low frequencies. This parameter change maintains sufficient accuracy for capacity retention rate calculation while dramatically improving measurement efficiency
Solution Approach 2:
The patent applies partial action by measuring at selected frequency points within the diffusion region d (0.1 Hz to 10 Hz) rather than requiring complete measurement coverage of the vertical region dc. This partial measurement approach achieves sufficient accuracy while significantly reducing measurement time and improving productivity
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 quick and accurate calculation of battery capacity retention rate, minimizing temperature influence and reducing measurement time to a practical range, suitable for in-use batteries.
Implementation Method 1
an impedance measurement unit for measuring complex impedance of a rechargeable battery
Implementation Method 2
a parameter calculation unit for calculating a parameter representing a ratio of a difference between measured angular speeds of two complex impedances having different measured angular speeds in a diffusion region among a plurality of measured complex impedances to a difference between imaginary components of the two complex impedances
Data Source
AI summary
A battery capacity measuring device that measures the battery capacity of a rechargeable battery includes an impedance measurement unit that measures the complex impedance of a rechargeable battery, which is a subject to measurement, based on application of measurement AC power, a parameter calculation unit that calculates a parameter that is a ratio of a difference between measured angular speeds of two complex impedances having different measured angular speeds in a diffusion region among a plurality of measured complex impedances to a difference between components of the two complex impedances, and a capacity calculation unit that calculates the capacity of the rechargeable battery based on information that is set in advance and indicates the relationship between the capacity of the rechargeable battery and the parameter and a parameter calculated by the parameter calculation unit.