Battery Cell Impedance Measurement for Harmonic-Aware Charging
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Solution Overview
Problem
Conventional charging techniques for battery cells are inefficient due to uncontrolled harmonics, which increase impedance, leading to energy loss, heat generation, capacity loss, and reduced battery life, while rapid charging systems require costly electronics and slow charging systems prolong the recharging operation.
Innovation Solution
Systems and methods for determining complex impedance characteristics of battery cells to optimize charge waveforms by adjusting harmonic components, minimizing real and imaginary impedance values, and controlling charge signals based on measured impedance profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rapid recharging systems are used to reduce recharging time, then charging speed is improved, but system cost increases due to costly high-power electronics and complex current limit and overvoltage circuitry
Solution Approach 1:
The patent applies parameter changes by measuring impedance characteristics (real and imaginary components) at different frequencies and using these measurements to dynamically adjust charging parameters. The system determines optimal charging conditions by analyzing how impedance varies with frequency, then modifies charging voltage and current parameters accordingly to achieve rapid charging without requiring complex high-power electronics
Solution Approach 2:
The patent implements feedback by continuously measuring voltage amplitude and current amplitude during charging, calculating impedance ratios, and using these measurements to adjust the charging signal. The system obtains complex impedance characteristics based on multiple impedance ratios and uses this feedback loop to optimize charging in real-time, eliminating the need for complex protective circuitry
2Device complexity
If conventional charging techniques are used to reduce system cost, then device complexity is reduced, but charging efficiency deteriorates due to uncontrolled harmonics increasing impedance
Solution Approach 1:
The patent changes the charging approach by introducing controlled harmonic components at specific frequencies that minimize impedance. By measuring impedance at multiple frequencies and identifying the frequency with minimum real impedance, the system adjusts the charging signal frequency to match optimal charging conditions, thereby reducing energy loss without increasing system complexity
Solution Approach 2:
The patent applies dynamics by making the charging signal adaptive rather than static. The system dynamically adjusts charging parameters based on real-time impedance measurements, modifying voltage and current waveforms to follow optimal charging paths. This dynamic adjustment allows efficient charging using simple electronics that adapt to battery conditions
3Device complexity
If uncontrolled harmonics are present in charging signals, then device complexity is reduced, but heat generation increases and battery life is reduced
Solution Approach 1:
The patent changes parameters by controlling the frequency and harmonic content of charging signals based on impedance measurements. By adjusting the charging signal to operate at frequencies where impedance is minimized, the system reduces resistive heating and energy dissipation, thereby extending battery life without requiring complex thermal management systems
Solution Approach 2:
The patent converts the typically harmful effect of harmonics into a beneficial tool by deliberately introducing controlled harmonic components at specific frequencies. These controlled harmonics are used to minimize impedance and reduce heat generation, transforming what is normally a source of energy loss into a mechanism for improving charging efficiency and reducing thermal stress on the battery
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
Improves charging efficiency, reduces energy loss, extends battery life, and minimizes heat generation by optimizing charge waveforms to match impedance characteristics, thereby enhancing charging speed and capacity utilization.
Implementation Method 1
obtaining, via a processing device, a plurality of measurements of a voltage amplitude and a current amplitude of charge waveform applied to an electrochemical device
Data Source
AI summary
A system is disclosed for determining complex impedance characteristics of one or more battery cells based on the charge signal applied, or to be applied, to the battery cell. Implementations may include measuring the impedance of a battery cell to, in some instances, determine a frequency component or harmonic that defines, at least a portion, of a waveform shape for charging the battery cell. In one implementation, the impedance at the battery cell may be measured or estimated from a discrete charge period being applied to the battery cell or from multiple discrete charge periods applied to the battery cell. The measured differences between the amplitude and time components of the voltage and current waveforms may be used to determine or estimate the magnitude, phase shift, real, and/or imaginary values of the impedance at the battery cell.