Battery Cell Fast Charging with Staged Pulse-Rest Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fast charging methods for lithium-ion batteries, such as CCCV and MSCC, cannot charge batteries in less than one hour due to excess heat generation, lithium metal plating, materials degradation, reduced cycle life, safety concerns, and thermal runaway, and lack reliable methods to detect crucial degradation phenomena like lithium plating.
Innovation Solution
The Voltage Staged Intermittent Pulse (VSIP) method, which applies a series of constant voltage stages with intermittent rest periods, adjusts charge parameters based on discharge capacity variations, and uses machine-learning techniques to maintain optimal charging conditions, ensuring safe and efficient charging within 30 minutes while preventing lithium plating and thermal issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant current and constant voltage charging methods (CCCV, MSCC) are used to charge lithium-ion batteries quickly, then charging speed is improved, but excess heat generation, lithium metal plating, and reduced cycle life occur
Solution Approach 1:
The charging process is divided into multiple voltage stages (V1, V2, V3, etc.) with progressively increasing voltage levels. Each stage includes intermittent pulse charging followed by rest periods, segmenting the continuous charging process into controlled discrete steps that prevent harmful effects while maintaining fast charging capability
Solution Approach 2:
The charging method employs periodic pulse charging followed by rest periods within each voltage stage. This periodic action allows the battery to dissipate heat and prevent lithium plating during rest intervals, while the pulse charging phases deliver high current for fast charging, resolving the contradiction between charging speed and battery reliability
2Productivity
If fast charging is implemented to reduce charging time below 60 minutes, then productivity is improved, but temperature increases and safety issues arise
Solution Approach 1:
Intermittent pulse charging followed by rest periods creates periodic thermal cycles that prevent continuous heat accumulation. The rest periods allow heat dissipation while maintaining overall fast charging capability, resolving the contradiction between charging time and temperature control
Solution Approach 2:
Dividing the charging process into multiple voltage stages with intermittent pulses segments the heat generation process, allowing thermal management at each stage rather than continuous heat generation, thus maintaining fast charging while controlling temperature
3Use of energy by moving object
If higher energy density is pursued to extend driving range, then the driving range is improved, but the charging time increases above 60 minutes
Solution Approach 1:
The periodic pulse charging method enables high current charging without the harmful effects that normally limit fast charging of high energy density batteries. This allows batteries with higher energy density (250 Wh/kg and above) to be charged quickly below 60 minutes, resolving the contradiction between driving range and charging time
4Use of energy by moving object
If lithium-ion batteries are used to achieve high energy density and low cost, then energy density is improved, but fast charging causes lithium metal plating and thermal runaway
Solution Approach 1:
The rest periods inserted between pulse charging phases preemptively prevent lithium metal plating by allowing the battery chemistry to stabilize and dissipate local concentration gradients before the next pulse. This preliminary anti-action stops plating before it can occur, enabling fast charging of high energy density lithium-ion batteries
Solution Approach 2:
The periodic pulse-rest cycle creates conditions that prevent lithium plating during high current charging, allowing high energy density batteries to be charged quickly without the harmful plating effect that normally limits fast charging capability
Data Source
AI summary
A method for life extension of a battery cell, provided with charge/discharge terminals to which a charging voltage can be applied with a flowing charging current, comprises: applying to terminals of the battery cell a plurality of constant voltage stages, each stage comprising intermittent voltage plateaus, letting the charging current go to zero for a rest period until an ending condition is reached, collecting data on previous discharge capacities measured during previous charge cycles, calculating a relative variation of the discharge capacity, comparing the calculated relative capacity variation to a predetermined threshold, if the calculated relative capacity variation exceeds the threshold, modifying at least one charge parameter among a selection of charge parameters including the duration of the voltage plateau, the variation of the voltage stage, and the rest time, so as to bring back the relative capacity variation below the threshold.