Battery Formation Pulse Sequencing for Uniform SEI Layers
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Solution Overview
Problem
Current battery formation processes are lengthy, expensive, and result in non-uniform SEI layers, leading to degraded battery performance and significant energy losses.
Innovation Solution
A method involving a sequence of pulse charging cycles with alternating positive and negative pulses, including a net zero charge phase, a net positive charge phase, and a frequency adjustment phase, to control the formation of a stable and uniform SEI layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional continuous charging methods are used for battery formation, then the battery can be charged, but the formation time is lengthy and energy losses are significant
Solution Approach 1:
The patent applies periodic pulsed charging instead of continuous charging. The charging process uses alternating positive and negative pulses at specific frequencies (e.g., 1 Hz, 10 Hz, 100 Hz) to form the SEI layer more rapidly. This periodic action reduces formation time from days to hours while maintaining effective SEI layer formation by continuously refreshing the electric field at the electrode surface.
Solution Approach 2:
The patent changes the charging parameters by using variable frequency pulses and alternating polarity. The frequency is adjusted during different stages of formation (e.g., starting at 1 Hz and increasing to 100 Hz), and the polarity alternates between positive and negative. These parameter changes enable faster formation kinetics while controlling energy consumption and heat generation.
2Reliability
If conventional charging methods are used, then charging can proceed, but the SEI layer formed is non-uniform, leading to degraded battery performance
Solution Approach 1:
The periodic pulsed charging creates uniform SEI layer formation by continuously refreshing the electric field distribution across the electrode surface. The alternating pulses prevent localized concentration gradients and ensure homogeneous ion distribution, resulting in uniform SEI thickness and composition throughout the battery cell.
Solution Approach 2:
The patent employs dynamic adjustment of pulse frequency and polarity during the formation process. The frequency is varied (e.g., 1 Hz, 10 Hz, 100 Hz) and polarity is alternated to adapt to the evolving SEI layer characteristics. This dynamic control ensures uniform SEI formation even as the layer thickness changes during the process.
3Productivity
If conventional formation processes are used, then the battery can be formed, but energy losses are significant
Solution Approach 1:
The patent reduces energy losses by changing the charging parameters to pulsed mode with alternating polarity. The periodic interruption of current flow allows relaxation of concentration gradients and reduces resistive heating. The variable frequency pulses optimize the balance between charging efficiency and energy consumption, significantly reducing overall energy losses compared to continuous charging.
Solution Approach 2:
The periodic pulsed charging with alternating polarity reduces energy losses by preventing continuous resistive heating and concentration polarization. The pulses are designed with appropriate duty cycles and frequencies to maximize charging efficiency while minimizing energy dissipation as heat, thereby improving overall formation 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
This approach reduces formation time, enhances SEI layer uniformity, and improves battery performance in terms of fast charging and capacity retention.
Implementation Method 1
applying a first set of pulses, having a first frequency, to a battery, wherein the first set of pulses carry a net zero charge; after applying the first set of pulses to the battery, measuring a first battery parameter
Implementation Method 2
During charging and discharging of the battery, ions move between the positive electrode and the negative electrode
Data Source
AI summary
Disclosed are methods, systems, and devices for battery formation. A first set of pulses, having a first frequency, and that carry a net zero charge, are applied to a battery. After the first set of pulses are applied to the battery, a second set of pulses that carry a net positive charge are applied to the battery. The second set of pulses are either applied after expiry of a particular time period following the application of the first set of pulses, or based on some battery measurements. After the second set of pulses are applied to the battery, a battery parameter is measured, and based on the measured battery parameter, a third set of pulses, having a second frequency, and that also carry a net zero charge, are applied to the battery.