Rechargeable Battery Essay

Rechargeable Batteries

What are Rechargeable Batteries?

Dictionary definition of a battery: “a group of two or more cells connected together to furnish electric current; also: a single cell that furnishes electric current.” (MARIUM WEBSTER) With this into consideration, a rechargeable battery is the exact same thing, except that is has the ability to be used and reused for a prolonged period of time. In most instances, rechargeable batteries are referred to as secondary batteries or cells and this is because of the nature of its reversible electrochemical reactions. (CHEMWIKI)

There are two types of batteries, wet cell and dry cells. Wet cell batteries are commonly found in aviation, car batteries, electric utilities… etc. and they contain

In general, rechargeable batteries are made of multiple cells that each consist of an anode, cathode, electrolyte and a separator. (BRUANGROUP)

Figure 1 below is a charger, and when a cell is charged, the anode (positively charged electrode) attracts the negative charges from the left side of the separator and creating a disequilibrium because the positive charges cannot pass through the separator. When the ions move from cathode to anode, reduction occurs and it creates disequilibrium which shows the potential of the cells. When the battery is being discharged, ionic species are formed by the oxidation at the anode which then travels through an external circuit and into the cathode, performing work in the process. (BRUANGROUP)

Figure 1

Power density is defined as the maximum practical sustainable power per unit mass or volume and energy density is defined as the amount of energy stored per unit mass or volume. (BRUANGROUP) High power density systems require the battery to be able to support a high rate of transfer of energy in and out of the cell(s), but these batteries could get permanently damaged due to self-heating during the fast charge and discharges which limit the maximum power of the battery High energy density is critical because otherwise, the cell would be too heavy and or large. There are tradeoffs for high density power. It could be improved at the cost of energy density however, the certain applications cannot sacrifice the energy densities i.e. automotive and high power portable tools, power grid stabilization… etc.

Types of Rechargeable Batteries

All batteries come in a multitude of sizes, AA, AAA, C, D and 9-volts. (BLOGBATTERYFORCE)

• Nickel Cadmium (NiCd)

NiCd batteries were the first popular rechargeable batteries and could perform in cold conditions. They are robust and have medium energy density. (BLOGBATTERYFORCE)

• Nickel Metal Hydride (NiMH)

Better than NiCd batteries in all aspects and has a higher energy density. However, it does have a poor charge retention rate. Meaning that its ability to charge/ recharge habitually is not as efficient. (BLOGBATTERYFORCE)

• Lithium-ion (Li-ion)