Battery Charging System Using Real-Time EIS for Pulse Optimization
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Solution Overview
Problem
Existing battery charging methods do not effectively adapt to real-time battery conditions, leading to inefficient energy transfer and potential degradation of lithium-ion batteries, such as the formation of dendrites which can cause short circuits and reduce battery life.
Innovation Solution
A battery charging system that uses a pulse train generator to produce optimized charging currents based on real-time Electrochemical Impedance Spectroscopy (EIS) measurements, adjusting pulse parameters such as amplitude, length, and width to match battery conditions, thereby optimizing the charging process and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant current charging is used, then charging speed is maintained, but battery degradation and dendrite formation increase
Solution Approach 1:
The patent applies dynamics by transitioning from constant current charging to pulse width modulated (PWM) charging, where the duty cycle dynamically adjusts based on real-time EIS measurements. This allows the charging current to adapt to changing battery conditions, maintaining high charging speed while preventing degradation and dendrite formation through optimized pulse parameters.
Solution Approach 2:
The patent implements parameter changes by modifying charging current characteristics based on EIS-derived battery state parameters. The system continuously monitors impedance changes and adjusts pulse width, frequency, and amplitude to optimize both charging efficiency and battery health, resolving the contradiction between speed and reliability.
2Loss of time
If high current charging is applied, then charging time is reduced, but heat generation and battery degradation increase
Solution Approach 1:
The patent employs periodic action through pulsed charging with optimized duty cycles. Instead of continuous high current, the system applies periodic current pulses with appropriate width and frequency, reducing average heat generation while maintaining effective charging. The pulse timing is optimized based on real-time battery impedance measurements to minimize thermal effects.
Solution Approach 2:
The system maintains continuity of useful action by using high-frequency pulse charging that effectively delivers continuous energy transfer while allowing brief relaxation periods. This ensures charging efficiency is maintained without sustained heat buildup, as the pulses are frequent enough to maintain ion concentration gradients while providing thermal management benefits.
3Adaptability or versatility
If real-time EIS measurements are performed, then charging optimization is achieved, but measurement time and system complexity increase
Solution Approach 1:
The patent applies universality by designing the EIS measurement system to serve multiple functions: characterizing battery state, optimizing charging parameters, and monitoring battery health. The same measurement infrastructure supports various charging strategies and battery types, reducing overall system complexity while maintaining adaptability.
Solution Approach 2:
The system implements self-service by using the battery's own impedance characteristics as the measurement signal. The charging controller performs EIS measurements using the existing charging current path and voltage sensing, eliminating the need for separate measurement hardware. The battery effectively measures itself through its response to applied charging pulses.
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
The system enhances battery cycle life by adapting charging currents in real-time, reducing the risk of dendrite formation and improving overall battery health through continuous or intermittent EIS measurements during charging.
Implementation Method 1
Electrochemical Impedance Spectroscopy (EIS) has been in use for a number of years to test rechargeable batteries, such as lithium ion batteries. EIS is well suited for observing reactions in the kinetics of electrodes and batteries.
Implementation Method 2
Other parameters that can be measured with use of EIS relate to the double layer effect, which is the formation of two layers of opposite polarity at the interface between electrode and electrolyte. The charge stored on one side is equal in value and opposite in sign with respect to the charge stored on the other side.
Implementation Method 3
The shape of such curves is related to the reaction mechanism, transport of the reactants from the bulk of the phase to the interface, and transport of the product in the opposite direction
Implementation Method 4
The SEI influences the kinetic behavior of the electrode, the irreversible charge consumed during cycling, and the cycle life.
Data Source
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AI summary
A battery charging circuit can produce a pulsed charging current to charge a battery. During charging, without disconnecting the pulsed charging current from the battery, EIS measurements can be made. The pulsed charging current can serve double-duty, for battery charging and as a drive signal for the EIS measurements. The EIS measurements are analyzed to assess the condition of a battery. The EIS measurements can be used to alter parameters of the pulsed charging current to improve battery life. In some instances, the parameters of the pulsed charging current can be momentarily changed for the purpose of making the EIS measurements, and then restored subsequent to making the measurements to parameters suitable for battery charging.