Battery Charging Control for Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium batteries face the challenge of lithium dendrite growth during charging and discharging, leading to internal electrical short circuits and potential ignition, as lithium ions deposit irregularly on the cathode, necessitating a method to suppress this growth.
Innovation Solution
A charging apparatus and method that includes a voltage detector, current generator, and controller to manage current flow between the battery terminals, alternating between direct current (DC) and alternating current (AC) with periodically reversed directions, and adjusting current and voltage peaks based on temperature, to scatter lithium ions and prevent dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct current (DC) is used for charging the lithium battery, then charging efficiency is improved, but lithium dendrite growth occurs leading to internal short circuits
Solution Approach 1:
The patent applies periodic action by alternating between DC charging mode and AC intermittent mode. During DC charging, lithium ions are efficiently inserted into the cathode. During AC intermittent periods, the current direction reverses, causing lithium ions to be extracted from the cathode surface, preventing dendrite formation. This periodic switching resolves the contradiction by maintaining high charging efficiency while eliminating the harmful dendrite growth that would otherwise occur with continuous DC charging.
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that the AC intermittent periods are optimized in duration and frequency to prevent dendrite formation without significantly interrupting the overall charging process. The controller adjusts the duty cycle and timing to maintain continuous effective charging while periodically reversing current to scatter lithium ions, thus preserving charging efficiency while ensuring battery safety throughout the charging cycle.
2Reliability
If alternating current (AC) is used intermittently to suppress lithium dendrite, then battery safety is improved, but charging time increases
Solution Approach 1:
The patent uses periodic action with optimized parameters where AC intermittent periods are brief and strategically timed during the charging cycle. The controller switches between DC and AC modes at optimal intervals to prevent dendrite formation without significantly extending total charging time. This resolves the contradiction by maintaining battery safety through periodic current reversal while minimizing the time penalty through efficient duty cycle management.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the frequency, amplitude, and duty cycle of the AC intermittent periods based on charging state and temperature conditions. The controller modifies these parameters to achieve dendrite suppression with minimal impact on charging speed, thus resolving the contradiction between battery safety and charging time by optimizing the temporal and electrical characteristics of the AC intervention.
3Reliability
If high current amplitude is used during intermittent period, then lithium ion scattering effect is enhanced, but energy loss increases
Solution Approach 1:
The patent applies parameter changes by optimizing the amplitude, frequency, and duration of AC intermittent periods to achieve effective lithium ion scattering with minimal energy loss. The controller adjusts these parameters dynamically based on battery state, using higher amplitudes only when necessary for dendrite suppression while reducing amplitude during stable charging phases. This resolves the contradiction by finding the optimal parameter set that provides sufficient ion scattering effect while minimizing unnecessary energy consumption.
Solution Approach 2:
The patent applies partial action by using AC intermittent periods with just sufficient amplitude and duration to scatter lithium ions and prevent dendrite formation, rather than continuously applying high amplitude current. This partial intervention during critical moments achieves dendrite suppression effectiveness while avoiding excessive energy loss that would result from continuous high-power operation, thus resolving the contradiction between suppression effectiveness and energy 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
The solution effectively suppresses lithium dendrite growth, preventing internal short circuits and allowing for safer and more efficient lithium battery charging, potentially enhancing energy density and extending battery life.
Implementation Method 1
The current generator outputs a first current for which a direction thereof between the terminals of the rechargeable battery is constant, in a charging period of the rechargeable battery, where the first current includes direct current (DC)
Implementation Method 2
a second current for which a direction thereof between the terminals of the rechargeable battery is periodically reversed, in an intermittent period of the rechargeable battery. The second current may include alternating current (AC)
Data Source
AI summary
The apparatus of charging a rechargeable battery includes a voltage detector which detects a voltage value between terminals of a rechargeable battery, a current generator which generates current for charging the rechargeable battery and outputs the generated current to the terminals of the rechargeable battery, and a controller which controls the current generator based on the voltage value detected by the voltage detector. The current generator outputs a first current for which a direction thereof between the terminals of the rechargeable battery is constant, in a charging period of the rechargeable battery, wherein the first current comprises direct current, and a second current for which a direction thereof between the terminals of the rechargeable battery is periodically reversed, in an intermittent period of the rechargeable battery.