Lithium Metal Battery Charging Profile for Dendrite Control
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Solution Overview
Problem
Lithium metal batteries face issues such as rapid consumption of electrolyte and lithium, formation of lithium dendrites leading to safety risks, and reduced cycle performance due to non-uniform deposition and interface peeling, especially during high-rate charging.
Innovation Solution
A controlled charging method with a two-stage process: a first stage with a step-wise ascending current pattern followed by a constant-voltage stage, optimizing the charging current based on the state of charge (SOC) to manage lithium deposition and reduce dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-rate charging is applied to lithium metal battery, then charging speed is improved, but lithium dendrites form and cycle performance deteriorates
Solution Approach 1:
The charging process is divided into multiple stages with different current rates. The patent applies a multi-stage charging strategy where the charging current is segmented into initial high-rate charging followed by lower-rate charging stages, allowing the battery to accept fast charging when SOC is low while preventing dendrite formation at higher SOC levels.
Solution Approach 2:
The charging current rate is dynamically adjusted based on the state of charge (SOC) of the battery. The patent implements a dynamic charging control system that monitors SOC and automatically adjusts the charging current to optimize both charging speed and battery safety, transitioning from high-rate to low-rate charging as SOC increases.
2Loss of time
If high charging current is used, then charging time is reduced, but lithium deposits non-uniformly and consumes electrolyte rapidly
Solution Approach 1:
The patent applies preliminary high-rate charging when the battery SOC is low (below threshold values such as 20%, 30%, or 40%), where the battery can accept high current without significant electrolyte consumption or non-uniform deposition. This preliminary fast charging action reduces overall charging time while avoiding the harmful effects of high current at later charging stages.
Solution Approach 2:
The charging current parameter is changed based on SOC thresholds. The patent implements parameter switching where the charging current rate is adjusted according to pre-set SOC thresholds, transitioning from high current (e.g., 1C, 2C, 3C) at low SOC to lower current (e.g., 0.5C, 0.2C) at high SOC to minimize electrolyte consumption and ensure uniform lithium deposition.
3Productivity
If constant high current charging is applied, then charging efficiency is improved, but lithium dendrites form and active lithium is lost
Solution Approach 1:
The patent implements periodic adjustment of charging current based on SOC monitoring. Instead of constant high current, the charging process periodically transitions between high-rate and low-rate charging stages, with current rate changes occurring at predetermined SOC intervals. This periodic action maintains high charging efficiency during low SOC periods while preventing dendrite formation during high SOC periods.
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 cycle life and high-rate charging performance by minimizing dendrite formation and side reactions, maintaining efficient electrolyte use, and extending the battery's operational life.
Implementation Method 1
During charging of a lithium-metal battery, lithium may deposit on a surface of the anode
Implementation Method 2
this application improves high-rate charging performance of an electrochemical device by optimizing a charging flow, and can improve the cycle life of the electrochemical device at similar charging times
Data Source
AI summary
An electronic device, a charging method for an electrochemical device, a terminal and a storage medium. The electronic device includes an electrochemical device that satisfies the following features: in a first stage of a charging process, a state of charge (SOC) of the electrochemical device being less than or equal to X, 70%≤X<100%. An average charging current when the SOC of the electrochemical device is less than or equal to 40% is A, an average charging current when the SOC of the electrochemical device is between 40% and X is B, and A<B. The electronic device can improve the cycle life of the corresponding electrochemical device with a charging time close to that of the current fast charging.