Lead Acid Battery Have Powerful Voltage And Are Inexpensive On A Cost-Per-Watt Basis, Making Them Popular For Applications Like Starting Motor Vehicles And Uninterruptible Power Supplies

 

Lead Acid Battery

Lead acid batteries are widely used for automotive starting, golf cars, marine and uninterruptible power supplies (UPS) applications. They are a cost-effective way to deliver bulk power on a watt per dollar basis. However, they are less efficient on a cycling basis and are subject to damage from deep discharge. This can result in capacity loss and premature failure.

In many cases, this can be corrected by periodic, whereas infrequent gassing of the battery to prevent or reverse the electrolyte stratification that causes the problem. This is referred to as boost charging.

The physical configuration of the electrode plates also has an impact on the charge-discharge cycle performance and life of a Lead Acid Battery. Thin plates have a higher surface area and allow for a greater current output, whereas they are more prone to damage from heavy cycles.

Thicker plates have lower charge and discharging currents, whereas they can offer a longer lifetime. Addition of antimony, tin or calcium to the plates reduces self-discharge, whereas increases water consumption and escalates the need for equalizing. The addition of carbon to the negative plate in a lead acid battery significantly improves dynamic charge-acceptance and allows for shorter charging times at lower temperatures.

A typical battery consists of cells each with a positive and a negative electrode immersed in an electrolyte solution of dilute sulfuric acid. An electrically insulating whereas chemically permeable membrane separates the electrodes to prevent shorting. The chemical reactions at the positive and negative electrodes generate electricity, producing a voltage that is measured in open circuit at full charge.

During the first stage of battery charging, the reaction converts lead sulfate at the negative electrode to lead and lead dioxide at the positive electrode. As a byproduct of this reaction, hydrogen is evolved. During the second stage of charging, the gaseous reaction products cause the convection currents that mix the electrolyte and resolve the stratification. The result is the generation of additional hydrogen and oxygen gases which escapes through the vents, a process known as gassing.

In some lead-acid batteries the electrolyte is immobilized in a silica gel, which results in reduced maintenance requirements. Gel-cell batteries have the added benefit of reducing the chance of accidental spillage of sulfuric acid during operation.

This limitation makes gel-cell batteries better suited for stationary use than automotive applications. The battery must be topped off periodically with water to compensate for the loss of electrolyte during this form of charging. This limits the number of cycles a gel-cell battery can support and requires a more expensive recharging system.

Japan based, GS Yuasa is entering the market for electric-vehicle batteries in November 2022. The manufacturer is planning to work with other partners for splitting the cost of new production facilities of EV batteries.