A study by the MEET Battery Research Center reveals that applying pressure during the formation of lithium-ion batteries enhances their performance and cycle life by mitigating gas evolution effects.
The impact of pressure on battery performance has two sides: appropriate pressure can ensure close contact between various components of the battery, prevent poor electrode interface contact, and improve the deposition mode of lithium ions, thereby enhancing the cycling stability of the battery.
Why do batteries need a pressure normal?
Applying a pressure normal to the active planes will keep the layers working together. Gas generation is a byproduct of electrochemical and chemical reactions inside the battery, which can occur when the battery is operational or in storage. The gas generation rate is dependent on chemistry, manufacturing quality, and battery management.
For all these gases, the critical pressure is significantly higher than the pressure inside the battery cells, so in this case the gas can be assumed to be ideal for temperature independent processes. This means that a reduction of the gas volume due to an expansion of the electrode would result in the gas pressure increasing.
Applying external pressure on the batteries can solve some of these problems and significantly extend their lifespan by improving stability, suppressing the growth of internal structures, and enhancing energy efficiency. Therefore, further research is needed on how to improve the batteries and how to bring new improved batteries .
The cell electrode pressure is required to keep the cell operating at it's peak performance over it's lifetime. However, is there an optimum pressure and why exactly does the cell need it? As the cell is charged lithium ions move into the graphite anode and the cell will increase in thickness.
How does mechanical pressure affect Li-ion battery life?
Mechanical pressure improves the electrical contact in Li-ion batteries. Reduced ionic pore resistance gets dominant in compressed cells at high C-rates. Compressibility is strongly dependent on the number of layers. Uncompressed Li-ion batteries tend to Li deposition. An optimum compressive pressure exists that extend the battery life.