Battery bloat or “swollen batteries” is a common occurrence among older lithium ion batteries. It is commonly caused by overcharging a battery and then leaving it unused for a long time. It may also be caused by extreme changes in temperature. More often than not, battery bloat essentially “kills” the battery, rendering it unusable or unsafe for further use.
Battery bloat has been one of the primary issues affecting lithium batteries today. It has effects ranging from a simple misfit to a battery’s socket up to wide-ranging recalls. Some examples of these recalls are those which affected the BP-6M line of Nokia batteries, used in many modern Nokia phones and affected 17 inch MacBook Pros. This is due to the concern that bloated batteries explode more easily than non-bloated ones.
These recalls have cost consumers and the companies millions of dollars in materials, transportation and also in the wasted time. It is also a form of bad publicity for the manufacturers, since their products will be perceived to be of low quality. Thus, it is imperative that we understand how battery bloat occurs and if any alternatives can be found which can stop the trend of battery bloat.
Battery bloat is primarily due to the irreversible chemical reaction which a lithium-based cathode undergoes upon charging. The cathode will permanently liberate elemental lithium and form a metal oxide composed of lithium’s “partner” metal. In most lithium ion batteries in the market, the partner metal is cobalt, so overcharging it will form cobalt oxide. Cobalt oxide has a chemical structure radically different from the original lithium cobalt oxide form, which weakens the structure and causes battery bloat. In addition, cobalt oxide is a very toxic substance.
Lithium iron phosphate batteries (LFPs) currently manufactured by Evon help alleviate this problem through having an overcharge product which is structurally similar to the original product. This means that the molecular structure of the battery is unchanged, thus contributing to the strength of the battery material and preventing battery bloat. This means that a battery can be used for the device for a longer time, and there is less risk of chemical discharge, making it safer to use for handheld devices.
This is also particularly significant for devices which are often overcharged. It is a common habit for people to leave their cellphones charging while they sleep, or to leave their iPods to charge as long as they are using the computer. Having a more stable structure will allow the battery to tolerate more overcharging before any irreversible damage occurs to the battery or to the device.
However, it must be noted that any overcharging will adversely affect battery life, and as such, should be avoided as much as possible. Although batteries with a structure which can better handle overcharging may prolong the battery’s use, it will not in any way affect the degradation of the battery’s capacity and energy density.