Lead-Based Batteries

The History of the Battery

Although there is evidence of electrochemical cells dating back to 2000 years ago, the story of the first true battery starts with an Italian physicist by the name of Alessandro Volta. In 1800 Volta created the first battery based on pairs of copper and zinc discs, the Voltaic Pile. It was with the invention in 1836 of the Daniell Cell, which consisted of a copper pot filled with a copper sulphate solution, that batteries would be made that could deliver a reliable current and be put to industrial use. The first rechargeable battery, or secondary cell, was a lead-acid cell battery invented in 1859 by the French inventor Gaston Planté, whose work laid the foundation for the modern lead-based battery industry. The first practical lead-acid battery was developed by Henri Tudor in 1886 and was manufactured first in Luxembourg and then in Belgium, France, Germany and the United Kingdom.

Since then there has been steady improvement of this battery technology in parallel with other technologies such as the first dry cell (a battery with a non-liquid electrolyte), the zinc-carbon battery, in 1887, the nickel-cadmium battery in 1899, the nickel-iron battery in 1903, the nickel hydrogen battery in the early 1970s, nickel-metalhydride batteries in the late 1970s, and lithium and lithium-ion batteries since the late 1980s.

Batteries Today

Batteries come in all sizes, from personal batteries used to power MP3 players, toys, radios and smoke detectors, and rechargeable batteries in mobile phones, laptops and portable DVD players, to industrial and automotive batteries used to crank internal combustion engines in cars (starting, lighting and ignition, or SLI, batteries), power electrical vehicles and as support for renewable energy generation. Batteries are also widely used in motive (trucks, trains, ships, aviation, space) and stationary applications, such as providing back-up power for UPS (uninterruptible power supply) and telecommunication systems. As such, batteries are an ever present part of our day to day life from work and leisure, to communications and travel.

How Batteries Work

A battery is an energy storing system based on electrochemical charge/discharge reactions. During discharge the chemical energy is converted into electrical energy and during charge the electrical energy is reconverted into chemical energy. In a primary battery system only the discharge reaction can be used, and the battery’s components must be recycled. A secondary or rechargeable battery system is characterized by a charge/discharge reaction that is reversible, allowing for repeated use. The higher the reversibility of the reaction the more often a battery can be charged/discharged. The process of a full charge to full discharge and back to full charge is known as a cycle. A battery’s cycle life is how many cycles the battery can go through before the battery must be replaced. The electrical energy stored in a battery is directly related to the chemical energy being stored. The cathode incorporates an oxidizing material, the anode a reducing component. The laws of nature have fixed specific energy limits to electrochemical systems from the periodic table of elements (see above). However, most chemical reactions cannot be used in a battery system because they are not reversible in an electrochemical cell.

Batteries in Everyday Use

Batteries play numerous important roles in everyday life, from providing the initial power needed to start the engines of cars to acting as a backup source of electricity in telecommunications, public transportation and medical procedures. Batteries also have the potential to help reduce greenhouse gas emissions by efficiently storing electricity generated from both conventional and renewable energy sources and as a source of power for electric vehicles.

Applications of Industrial and Automotive Batteries

• Automotive Applications (including Cars, Trucks, Buses, Agriculture, Construction)
• Starting, lighting and ignition (SLI) batteries
• Start-Stop systems
• Mild, full and plug in Hybrid Electric Vehicles (HEV)
• Electric Vehicles (EV)
• Motive Applications
• Lift trucks and handling
• Trains, ships and aircraft
• Stationary Applications
• Uninterruptable Power Supply (UPS)
• Telecommunications
• Renewable Energy Systems (RES)
• Grid support

Battery Technologies

A broad range of different electrochemical systems and battery technologies exist today. There are currently four battery families dominating the automotive and industrial battery market

• Lead-based battery technology
• Nickel-based battery technology
• Lithium-based battery technology
• Sodium-based battery technology

The selection of one of these technologies depends on application requirements regarding performance, life, safety and cost.

Lead-Based Batteries

Lead-acid technology is the most widely used electrochemical system, used in numerous applications from back-up for uninterruptible power supplies and grid energy storage, to traction in battery electric vehicles and for starting, lighting and ignition (SLI) in conventional combustion engine vehicles.

The lead-acid battery is based on:

• Lead dioxide as the active material of the positive electrode,
• Metallic lead, in a high-surface-area porous structure, as the negative active material,
• Sulphuric acid solution as the electrolyte.

Lead-acid technology is composed of several sub-technologies distinguished by battery design and manufacturing process:

• Flooded lead-acid batteries,
• Valve-Regulated lead-acid (VRLA) batteries with electrolyte immobilized by a gel,
• VRLA batteries with the electrolyte immobilized in an absorptive glass mat (AGM)
• Vented lead acid batteries for industrial applications

Flooded Lead-Acid Batteries

In flooded lead-acid batteries, the positive plate (electrode) is comprised of lead dioxide and the negative of finely divided lead. Both of these active materials react with a sulphuric acid electrolyte to form lead sulphate on discharge and the reactions are reversed on recharge. Batteries are constructed with lead grids to support the active material and individual cells are connected to produce a battery in a plastic case. There are, however, major differences in battery construction depending on the duty cycle and application. The typical application of these batteries is the automotive industry; millions of these batteries are used to start and support the electrical system in today´s cars and trucks.

Valve-Regulated Lead Acid Batteries (VRLA) with Electrolyte Immobilized by a Gel or an Absorptive Glass Mat (AGM)

A secondary battery in which the cells are closed but have a valve that allows the escape of gas if the internal pressure exceeds a predetermined value, valveregulated lead acid batteries (VRLA) have a starved electrolyte either on glass fibres (Absorptive Glass Mat, or AGM) or as a gel (Gel technology) which allows for internal gas circulation. Water loss from overcharge is reduced to less than 10% through recombination. VRLA batteries can be installed in a free orientation and there are no leakages because of the absence of liquids. The construction of these batteries means that they do not require maintenance, making them especially advantageous for remote area installations. Today, AGM batteries are typically used in vehicles which are very well equipped and therefore have a correspondingly high cycling demand and cycling depth. A new booming market for AGM batteries is for their use in start-stop vehicles and this segment is expected to grow strongly over the coming years. Other applications include use in motorcycles and motor car racing due to their safety in the event of an accident and Gel VRLAs can also be found in electric wheelchairs due to their suitability for use indoors.

Vented Lead-Acid Industrial Batteries

Vented lead-acid batteries are covered secondary cells with an opening through which the products of electrolysis and evaporation are allowed to escape freely from the cells. Vented lead-acid batteries have a liquid electrolyte. The battery is closed by a vent plug and has a gassing rate more than 4 times higher than valve regulated batteries. Water loss by electrolysis during overcharge results in the production of hydrogen and oxygen gases. Vented lead-acid batteries are a well-established technology and are economical to produce. Maintenance of water refill depends on design features and application (reduction of refill by recombination plugs or custom refilling systems). The state of charge and age can be checked very easily in vented lead-acid batteries.

Vented lead-acid batteries are commonly found in various traction applications.

Source: Eurobat

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