Alkaline and carbon-zinc batteries are common in many self-powered devices. However, once the battery is depleted, it can no longer be used and is thrown away. It is estimated that around 15 billion batteries are manufactured and sold worldwide each year. Most of it ends up in landfills, and some is processed into valuable metals. However, while these batteries are unusable, they usually have a small amount of power left in them. In fact, about half of them contain up to 50% energy.
Recently, a team of researchers from Taiwan investigated the possibility of extracting this energy from disposable (or primary) waste batteries. A team led by Professor Li Jianxing from the University of Chengda in Taiwan focused their research on this aspect in order to promote the circular economy for waste batteries.
In their study, the researchers propose a new method called Adaptive Pulsed Discharge (SAPD) that can be used to determine the optimal values for two key parameters (pulse frequency and duty cycle) that: This parameter determines the discharge current. discarded battery. Battery. Simply put, a high discharge current corresponds to a large amount of recovered energy.
“Recovering a small amount of residual energy from household batteries is a starting point for reducing waste, and the proposed energy recovery method is an effective tool for reusing a large amount of discarded primary batteries,” said Professor Li, explaining the rationale for his research. published in IEEE Transactions on Industrial Electronics.
In addition, the researchers built a hardware prototype for their proposed method of restoring the remaining capacity of a battery pack capable of holding six to 10 different brands of batteries. They managed to recover 798–1455 J of energy with a recovery efficiency of 33–46%.
For ejected primary cells, the researchers found that the short circuit discharge (SCD) method had the highest discharge rate at the beginning of the discharge cycle. However, the SAPD method showed a higher discharge rate at the end of the discharge cycle. When using the SCD and SAPD methods, energy recovery is 32% and 50%, respectively. However, when these methods are combined, 54% of the energy can be recovered.
To further test the feasibility of the proposed method, we selected several discarded AA and AAA batteries for energy recovery. The team can successfully recover 35–41% of the energy from spent batteries. “While there seems to be no advantage in consuming a small amount of power from a single discarded battery, the recovered energy increases significantly if a large number of discarded batteries are used,” said Professor Li.
The researchers believe there may be a direct relationship between recycling efficiency and the remaining capacity of discarded batteries. Regarding the future impact of their work, Professor Lee suggests that “the developed models and prototypes can be applied to battery types other than AA and AAA. In addition to various types of primary batteries, rechargeable batteries such as lithium-ion batteries can also be studied. to provide more information about the differences between different batteries.”
Post time: Aug-12-2022