Industrial batteries translate chemical energy into electricity. They come in a variety of sizes and shapes to fit a wide range of applications. All batteries have positive and negative terminals, marked (+) and (-) respectively, and two corresponding electrodes. The electrodes must not touch each other. They are separated by the electrolyte, which facilitates the flow of electric charge between the electrodes. Finally, a collector conducts the charge to the battery's exterior and through the load.

When a battery is inserted into an electrical device, the device completes the circuit between the two terminals and triggers electrochemical reactions within the battery. The anode undergoes an oxidation reaction with the electrolyte, releasing electrons, while the cathode undergoes a reduction reaction and absorbs the free electrons. The product of these two reactions is electricity, which is channeled out of the battery and into the device.

Battery Types

Buyers can select between two basic types of batteries.

Primary batteries are disposable, non-rechargeable devices. They must be replaced once their energy supply is depleted.

Secondary or rechargeable batteries contain active materials that can be regenerated. When the energy produced by these industrial batteries drops below optimum efficiency, they may be recharged according to various methods, depending on the battery construction. Secondary batteries are useful in applications where frequently replacing disposable batteries is more costly, such as in electric vehicles, handheld power tools and automobile starters.

Battery Chemistry

Industrial batteries are manufactured using a variety of reactive elements. A battery's chemistry largely determines its cost, size and application.

Alkaline batteries are versatile primary batteries containing zinc and manganese dioxide. They feature a moderate energy density and are effective in both high and low drain applications.

Lead acid batteries are rechargeable batteries that represent about 60% of all industrial batteries sold worldwide. All lead batteries work on the same set of reactions and use the same active materials. At the positive electrode, lead dioxide (PbO₂) is converted to lead sulfate (PbSO₄). At the negative electrode, sponge metallic lead (Pb) is also converted to lead sulfate (PbSO₄). The electrolyte is a dilute mixture of sulfuric acid that provides the sulfate ion for the discharge reactions.

Lithium is used in both primary and secondary battery reactions. Lithium batteries are expensive and useful in specialty applications that require high energy density, such as laptops, high-end cameras, and cellular phones. A lithium battery can produce more than twice the voltage of a zinc carbon or alkaline battery.

Nickel is found in a variety of primary and secondary battery chemistries. Nickel oxyhydroxide is common in primary batteries, while secondary batteries may use nickel-cadmium (NiCd), nickel-metal hydride (NiMH), or nickel-zinc (NiZn). Nickel batteries are inexpensive and feature various energy densities and drain rates, depending upon the specific chemistry.

Zinc is used as a negative terminal material in inexpensive primary batteries. Zinc batteries use a variety of positive terminal materials, including carbon, chlorine, and oxygen; these batteries are respectively named zinc-carbon, zinc-chloride, and zinc-air. Zinc-air batteries are commonly used in hearing aid cells.

Battery Specifications

The Engineering360 SpecSearch database contains information about a variety of standardized sizes and shapes pertaining to both primary and secondary batteries. These specifications can be classified by consumer sizes, which are commonly available for general purpose applications, and non-consumer sizes for specialized uses such as photography and instrumentation. Batteries manufactured for specialty use come in a variety of shapes and sizes.

When selecting industrial batteries, buyers may also specify the product's voltage, capacity and intended applications.

Consumer Sizes

• Round batteries are taller than their diameter and have terminals on each end. Depending on the active materials used, they typically produce between 1.2 and 3 volts when fresh. Round batteries are commonly available in a variety of sizes, including AAA, AA, C and D.
• 9-Volt or PP3 batteries consist of six individual 1.5 V cells within a can. They are typically used in smoke detectors, alarms, and other consumer products.

Various Sizes of Round Alkaline Batteries. Image credit: EIS

Non-consumer Sizes

• AAAA batteries are used in small devices such as laser pointers, penlights and glucose meters.
• A batteries are approximately the same length as the AA size, but with a larger diameter. They are commonly used in older laptop batteries and consumer battery packs.
• N batteries are roughly three-fifths the length of an AA battery. Similarly to AAAA batteries, they are used in small device applications.
• Sub-C batteries are typically used in consumer battery packs for power tools or radio-controlled vehicles.
• Fractional batteries are expressed as a fractional number combined with a common battery size. For example, a 1/2AA battery is half the length of an AA battery but shares the same diameter. Common fractional batteries include 1/3AA, 2/3AA, 1/2A, 2/3A, 4/5Cs and 1/2D.

Non-consumer batteries. Left to right: AAAA, N (with AA for scale), sub-C, 1/2AA (with AA). Image credit: Lead holder

Specialty Cells

• Battery packs consist of primary or secondary batteries bundled together with a connector for use in phones, radio-controlled vehicles and other consumer devices.
• Coin or button cells are available in numerous sizes and are used in watches, calculators and hearing aids.
• Lantern batteries typically produce 6 V and have spring or screw terminals.
• Prismatic cells are rectangular batteries which have slightly lower energy densities than traditional cylindrical cells. Although prismatic cells are expensive to manufacture, their unique construction offers a more efficient use of space, especially in designing battery packs.
• Sachet cells are a relatively recent battery development designed to fit in a specific space. Their electrodes are surrounded by a flexible foil packaging which replaces the hard case of traditional batteries, making sachet cells lighter.
• Thin film batteries are very thin devices which can be integrated into circuits or plastic cards.

Voltage

Battery voltage refers to the electric potential difference between the positive and negative terminal. Manufacturers typically specify the battery's nominal voltage, although its actual discharge voltage can vary depending on the battery's charge and current. For example, a battery cell with a nominal voltage of 2 V actually discharges between 1.7 and 2.0 volts at a given time. Most round consumer batteries carry a nominal voltage of 1.5 V, while a car battery is typically 12 volts. Depending on the battery materials and application, voltage can range from a fraction of a volt to several kilovolts.

Capacity

The amount of charge a battery can store is known as its capacity. Charge is typically measured in amp-hours or milliamp-hours (Ah or mAh). Most manufacturers specify capacity as the constant current that a new battery can supply for 20 hours. For example, a battery rated at 200 Ah can supply 10 A over a 20 hour period at room temperature. If the current supply to the same battery is increased, the capacity will then decrease.

Applications

Batteries are manufactured for use in numerous applications.

• Consumer batteries are used for general purpose consumer applications, such as cameras, radio-controlled cars, toys, and laptops.
• Energy batteries are manufactured for use in oil, natural gas and solar applications.
• Industrial batteries are deep cycle batteries used in forklifts and other industrial applications.
• Medical batteries are used for life support systems, hearing aids and wheelchairs.
• Military batteries are often manufactured to MIL-SPEC requirements.
• Transportation batteries are designed for use in aircraft, boats, automobiles and electric vehicles.
• Stand-by/UPS batteries are used in uninterruptible power supplies (UPS) for emergency lighting and alarms.

References

Battery University - Battery Knowledge

Electropaedia - Battery and Energy Technologies