A lead-Acid battery is a type of rechargeable battery commonly used for high power supply. They are typically larger in size with sturdy and heavy construction, can store a large amount of energy, and are generally used in inverters and automobiles. Lead acid battery are very popular, even after competition with lithium-ion batteries, the demand for lead-acid batteries is growing every day as they are cheaper and easier to use compared to lithium-ion batteries.
These batteries have literally dominated the marketplace for many years ever since their invention back in the early 1800s. Despite the batteries slight amounts in energy to volume and energy to weight, it has the ability to deliver higher surge currents. These are batteries that use lead peroxide and sponge lead to transform chemical energy into electrical energy. They are mainly used in substations and power systems because of increased cell voltage levels and reduced costs.
Lead-acid Battery Construction, Working Principle
When it comes to lead-acid batteries, containers and plates are the most important components. The container stores chemical energy that is transformed into electrical energy with the help of the plates. In the following paragraphs, we will provide an in depth description of each component used in the lead-acid battery construction.
- Container: The lead-acid battery container is made of lead-lined wood, glass, solid rubber of bituminous composite, ebonite, ceramic material, or molded plastic, and is placed on top to prevent electrolyte discharge. At the bottom of the container, there are four ribs, two of which rest the positive plate and the other two supports the negative plate.
- Plate: The lead-acid battery plate has a varied design and all consists of some type of grid that consists of lead and active material. The grid is necessary to conduct the electric current and allocate the current evenly to the active substance. If the current is not evenly distributed, then the active substance will fall out.
Battery plates are of two types, the formed plate, and pasted plates. The formed plates are mainly used for static batteries and are heavy and expensive. These plates have long durability and it is not likely to easily lose its lively components even in process of constant charging and discharging. The pasted plates are mainly used in the construction of negative plates than from those positive plates.
- Battery Terminals: The battery has negative and positive terminals. The positive terminal has a diameter of 17.5mm and is slightly larger at the top than the negative terminal which has a diameter of 16mm.
- Separators: These are small sheets of non-conductive substance made from chemically treated Leadwood, mats of glass fiber, spongy rubber, and glass fiber mats, they are found between the negative and positive to protect the separator from each other. The Separators are upright stitched on one side and smooth on the other side.
- Active Component: An active component is a component that actively contributes to the chemical reaction processes that occur in the battery mostly at the time of charging and discharging. The following are the active components:
Spongy lead: this substance form the negative active components
Lead peroxide: This is a positive active component.
Dilute Sulfuric Acid: Used primarily as an electrolyte solution.
The spongy and lead, which are both positive and negative active substances, have low mechanical strength and can be used alone.
Lead-acid Battery Construction Working Principle
There is a vast chemical involved in the charge and discharge process of a lead-acid battery. Dilute sulfuric acid H2SO4 molecules split into two parts when the acid dissolves. It will create negative ions and negative SO4- ions. The two electrodes are connected, namely the anode and the cathode. Two electrodes are connected as plates namely, the cathode and the anode. The cathode attracts the positive ions, while the Anode attracts the negative ions. The battery has two states of chemical reaction, charge, and discharge
Dry Lead-acid Battery Construction
These batteries were introduced due to problems inherent in the storage of wet-charged types. At the time, materials used to produce batteries were such that wet-charged batteries suffered high rates of self-discharge and sulfur when it is not in used and were deteriorated on the shelf. The dry-charged battery offered the customer a new battery and provided distributors and retailers with the means of safely moving a wide range of products and larger stocks. In many cases, transportation was easy and cheaper with a dry battery charged.
The technical advances brought about low maintenance and maintenance-free batteries;they have eliminated the problems with wet-charged systems in some markets. Today, dry acid batteries are rarely seen in the retail market. However, other markets still require these batteries, and dry charging is done to facilitate shipping to export markets.
Valve Regulated Lead-acid Battery Construction
A valve regulated lead acid battery (VRLA), also refers to as a sealed lead acid battery (SLA), is a kind of lead acid battery that has a limited amount of electrolyte that is absorbed in the Plated separator or formed into a gel that fits into the positive and negative plates to ease the recombination of oxygen within the cell.
The two basics kinds of VRLA batteries are absorbent glass mat and a gel cell. A gel cell is a valve-regulated lead-acid battery.AGM batteries come with a fiberglass mesh among the battery plates that serve to contain the electrolyte and separate the plates. The battery cells are made of flat plates that are similar to the regular lead-acid battery cells. These batteries consist of a pressure relief valve that is activated when the battery begins to build up hydrogen gas pressure, which means it recharged. Activating this valve allows a certain amount of gas to escape so that the battery capacity will be reduced.
This type of battery can be aligned in any direction, unlike the general lead batteries because it must be kept in the vertical direction to avoid any type of acid leakage and also to consider if any vertical alignment of the plates occurs. Because compared to vertical alignment, horizontal alignment improves service life. The following are the advantages of Valve regulated lead-acid battery.
The VRLA battery does not need maintenance and it is not necessary to refill the water periodically
It reduces ventilation demand.
VRLA battery capacity range is high (12,000 Ah)
VRLA batteries will have a longer life span, the useful life of these batteries will be about 10 years.
VRLA batteries are inexpensive