Why Do Pouch Cells Require Ultra-Low Pressure When Sorting?

Their unique structure makes it imperative to handle pouch cells safely. Ultra-low pressure is often key when pouch cells are being sorted and tested – but why? Read on!
Pouch cells are used in a variety of applications today – especially EVs, but also energy storage and consumer electronic uses. Due to their arrangement, pouch cells require some special handling whilst sorting and testing.
Why is ultra-low pressure so important when a pouch cell is being sorted?
1. Pouch Cell Structure and Sensitivity
The pouch cell is often somewhat forgiving in terms of non-circular forms, constructed out of soft / thin foil. Softer than alternative forms, and as such, subject to compromising physical damage more easily.
Ultra-low pressure maintains the original outline of the important pouch cell. So little exertion is used that the pouch can utilise soft materials internally.However, if there is excessive pressure applied, that could potentially cause the contents of the pouch cell to shift/snap and primarily the electrodes, separators, and seals. These three things becoming ‘damaged’ could result in it being less efficient, less capacity or risk having safety hazards internally such as short circuits or thermal runaway.
By using ultra-low pressure, they ensure that the pouch cell themselves do not lose specific structural characteristics to ensure they do not permanently ‘damage’ themselves. The sorting equipment is designed to apply just the right amount of pressure to nudge the cells without damaging the internal structure of the cell.
3. Stopping the pouch cells leaking/rupturing
Pouch cells are sealed to stop the electrolyte leaking out; this is a large part of what makes them work between their cathode and anode. When it comes to sorting them, if they were subjected to pressure, it may cause the seals pressure and for it to leak or rupture which would affect the actual cell itself but also be a major safety hazard.
By using ultra-low pressure, they assure that the scores cells remains sealed for the pouch cell seals game day material is retained that should ‘not’ leave. No dangerous reactions should be permitted to occur.
4. Keeping an accurate score
One of the main, individual factors for battery sorting; is hyphenic by a long way, other words, how cells are sorted. The sort process is deliberately designed to separate them.
Pouch cells in sorting are initially separated by the individual characteristics of the cell itself; the things like capacity, voltage, internal resistance etc.
If of a cell is mechanically damaged in any way during the sorting process, it could in turn affect one of these characteristcs and the cell might be ‘sorted’ in the wrong group for instance.Ultra-Low Pressure allows the cells to retain their pristine state for accurate measurements and sorting. Greater quality control is permitted as manufacturers can reliably identify cells lower and higher in quality and sort them accordingly, saving higher quality cells for high-end applications.
5. Extending Life
Pouch cell manufacturers are seeking to make their battery cells more capable of holding bulk energy throughout more charging cycles. Maintaining the pouches structural state during the sorting process is important. Batteries in general do not like being ‘pressed’ and this kind of pressure damages the pouch causing degradation of the cells limited life, and shortening the cells lifetime to unrecoverable states.
Using ultra-low pressure sorting afforded the manufacturer the capacity to build a cell capable of lasting for more charge cycles, yield a higher margin product, and cater for premium deployment in electric vehicles, loads holding applications and so on.
6. Safety
Finally the sorting safety of the cell is paramount too. Too much pressure during sorting is a step backwards in cellphones safety, as easily pouch cells can rupture or deform which can happen spontaneously within the energy build up, leading to the hazards of burning, chemical leaking, or even explodes within extreme circumstances. Making use of ultra-low pressure upon this sorter/other handling equipment mitigates these risks and allows lower/existing rate of installation for operators (OEE).
Conclusion.
Pouch cells benefit from ultra-low pressure during sorting because pressing them makes them leak, plus because of how accurately the probe can measure, and detecting poor quality cells from quality cells. It sounds like an afterthought to be concerned about how much the pouches are pressed altogether during sorting, but for the manufacturers it must weigh up in improved warranty yield, adjustments were possible, and pleasingly the ultra-low levels make proper applications for cellphone sorting to be easy to accomplish.