As you have already came to know while coming across reviews of best power banks in India in the other post that there are basically two types of battery cells which general constitutes the power bank, namely the Lithium-ion and Lithium-Polymer. There has been great debate over which one is the better one, and in the relevant section of the great power bank buying guide post from Powerbanky, you are going to find some hint, but here, we are going to get here into much more details and find exactly which one is the best in terms of the functionality and ease of usage when it comes to the portable chargers.
There exists a technical term known to be self-discharging. Which basically declares the amount of the charge that a battery cell is going to discharge on its own when it is not in its use. It is normally calculated in percentage. Now, for the power banks, the self-discharging rate should be as low as possible and it is preferable that the battery cell constituting the portable battery pack is having no self-discharge.
The relevance of the self-discharge in the domain of the power bank is that, portable charger is basically a thing which we do not in general charge or power up every night unlike the mobile phones. Thus whereas for mobile phones the rate of self-discharge is not that important because whatever it be, it is not going to effect the functionality associated to the mobile phone. But for the external battery packs, we need that to be containing the charge within itself without leaking much when it is not in use.
Among Li-poly and Li-ion, Li-poly has extremely low self-discharge rate, whereas the Li-ion cells have a considerable rate of self-discharge, around 2%, that means the portable charger being built with the Li-ion is going to be losing charge at a rate of 2% even when you keep the charger full charged and leave it unused. This does not only decrease the amount of charge within this, but as well, gradually makes the capacity of the power bank depleted. So, with the conclusion to this self-discharging aspect, we are getting that the Li-poly power banks are much ahead in comparison to the Li-ions.
Moreover, when it comes to the aspect of the safety, Li-Poly is again going to beat the Li-ion category as the Li-poly being backed by the latest technological support, comes always with lesser prone to explode, gets less heated up or even comes with the standard safety measures always within itself. Whereas in the case of the Li-ion, the cells make in general the power bank much heated up and usually lacks the normal typical safety options with having greater prone to get exploded.
Hence, under such a discussion, we come to the point that, whenever it is the point of efficiency, be it the case of ability to sustain greater charge, or providing better security aspects, best portable power banks with built-in Li-poly cells are always better to choose than the Li-ion options.