Battery Cell Fast Charging With Staged Voltage Pulses
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Solution Overview
Problem
Current lithium-ion battery charging methods, such as CCCV and MSCC, are unable to charge batteries in less than an hour due to excess heat generation, lithium metal plating, and reduced cycle life, and lack reliable methods to detect crucial degradation phenomena like lithium plating, especially in fast-charging scenarios.
Innovation Solution
A Voltage Staged Intermittent Pulse (VSIP) method that applies a series of constant voltage stages with intermittent voltage plateaus and rest periods for the charging current, allowing for safe and efficient charging below 60 minutes while monitoring temperature and voltage limits, and utilizing machine-learning techniques to adjust parameters for optimal charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant current or constant voltage charging methods are used to achieve fast charging, then charging speed is improved, but excess heat generation and lithium metal plating occur reducing battery life
Solution Approach 1:
The charging process is segmented into multiple voltage stages (V1, V2, V3, etc.) with progressively increasing voltage levels. Each stage includes intermittent voltage plateaus followed by rest periods, dividing the continuous charging process into controlled discrete steps that prevent excessive heat and lithium plating while maintaining fast charging capability
Solution Approach 2:
The charging method employs periodic voltage plateaus and rest periods within each voltage stage. The current is intermittently applied with rest periods in between, creating a periodic action pattern that allows heat dissipation and prevents lithium metal plating while maintaining overall fast charging speed
2Productivity
If charging time is reduced below 60 minutes, then productivity is improved, but temperature control and voltage management become more difficult
Solution Approach 1:
The charging system dynamically adjusts voltage levels, current intensity, and rest period durations based on real-time battery state monitoring. The controller modifies charging parameters at each voltage stage to optimize charging speed while maintaining temperature and voltage within safe limits, enabling fast charging without excessive control complexity
Solution Approach 2:
The system continuously monitors battery temperature, voltage, and charging current, using this feedback to adjust subsequent charging stages. This feedback mechanism allows the controller to manage the increased complexity of fast charging by automatically adapting parameters to prevent overheating and overcharging
3Duration of action of moving object
If higher energy density is used to extend driving range, then operation time is improved, but power density and charging speed are limited
Solution Approach 1:
The method changes multiple charging parameters simultaneously - voltage levels are progressively increased through multiple stages, current intensity is modulated with rest periods, and charging profiles are dynamically adjusted. These parameter changes enable fast charging of high energy density batteries by preventing the heat and plating issues that normally limit charging speed
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 VSIP method enables full charging in under 30 minutes while maintaining battery integrity, preventing lithium plating, and extending the battery life, applicable to various battery chemistries and configurations, including those in series and parallel, with intrinsic balancing eliminating the need for cell balancing.
Implementation Method 1
a battery cell to be charged or discharged, having a positive electrode, a negative electrode and an electrolyte
Data Source
AI summary
A method for fast charging a battery cell provided with charge/discharge terminals to which a charging voltage can be applied with a flowing charging current, the method comprising the steps of: applying to terminals of the battery cell a plurality of constant voltage stages Vj, where Vj+1>Vj, j=1, 2 . . . , k, each voltage stage comprising intermittent nj voltage plateaus, between two successive voltage plateaus within a voltage stage, letting the charging current going to rest for a rest period, Rjp, 1≤p≤nj, the fast-charging method proceeding until either one of the following conditions is reached: a pre-set charge capacity or state of charge is reached, the cell temperature exceeds a pre-set limit value Tlim and the cell voltage has exceeded a pre-set limit value Vlim.