Pulse Charging Control for Faster Li-Ion Battery Formation
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Solution Overview
Problem
Lithium-ion batteries are inefficiently charged, leading to irreversible damage and underutilization of capacity due to the formation process, where batteries are charged to only 80% of their capacity, resulting in longer charging times for the remaining 20%.
Innovation Solution
A charging device that alternately supplies high-current charge pulses and discharge pulses to form a solid electrolyte interphase (SEI) layer in a discharged state, with specific current and time parameters to enhance battery formation and prevent overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the battery is charged to 100% capacity using conventional methods, then the charging time becomes exponentially longer, but if charged to only 80% capacity, then the energy storage is reduced and the battery capacity is underutilized
Solution Approach 1:
The patent applies periodic pulsed charging instead of continuous charging. The charging device delivers charge in periodic pulses with specific duty cycles, allowing the battery to charge to 100% capacity while maintaining reasonable charging time. The pulsed action creates favorable conditions for SEI layer formation and prevents the exponential time increase associated with conventional continuous charging methods
Solution Approach 2:
The patent changes the charging parameters by applying high current pulses during formation process. The charging current is controlled to be 1 to 3 times the rated current during specific formation stages, and the pulse width is optimized to 20-100ms. These parameter changes enable efficient charging while properly forming the SEI layer, resolving the contradiction between charging time and capacity utilization
2Speed
If high current is applied to charge the battery quickly, then the charging speed increases, but the battery may be irreversibly damaged and ions may be separated from the electrode material
Solution Approach 1:
The patent uses periodic pulsed charging with controlled duty cycles to deliver high current safely. Instead of continuous high current that would damage the battery, the charging is delivered in periodic pulses with appropriate width and interval. This periodic action allows fast charging while preventing irreversible damage and ion separation from electrode materials
Solution Approach 2:
The patent dynamically adjusts the charging current based on the battery's formation stage and state of charge. The charging current is controlled to be 1 to 3 times the rated current during formation, with pulse widths of 20-100ms. This dynamic control enables high charging speed while maintaining battery integrity by adapting the current level to the battery's real-time conditions
3Quantity of substance
If the formation process charges the battery to 100% capacity, then the energy storage is maximized, but the charging time increases exponentially due to current limiting at end-of-charge voltage
Solution Approach 1:
The patent applies periodic pulsed charging during the formation process to overcome the exponential time increase. The pulsed action with optimized duty cycles allows the battery to reach 100% capacity without the current limiting problems of continuous charging. The periodic delivery of charge enables efficient formation charging while maximizing total energy storage
Solution Approach 2:
The patent changes the formation charging parameters by using pulsed current with 1 to 3 times rated current and pulse widths of 20-100ms. These parameter changes enable the battery to be charged to 100% capacity during formation without the exponential time penalty of conventional methods, thus maximizing energy storage while controlling charging time
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
This method increases the lifespan and capacity of lithium-ion batteries by forming a robust SEI layer, reducing charging time and preventing salt generation, thereby improving battery performance and longevity.
Implementation Method 1
supplying charge pulses for charging a secondary battery
Implementation Method 2
supplying discharge pulses for discharging the secondary battery between the charge pulses
Data Source
AI summary
Provided is a method for operating a charging device, the method including the steps of supplying charge pulses for charging a secondary battery and supplying discharge pulses for discharging the secondary battery between the charge pulses while supplying the charge pulses, in which the charge pulses and the discharge pulses are alternately supplied from an activation start time point of the secondary battery.