Battery University

Battery Types

Alkaline - The most common type of non rechargeable battery. Alkaline batteries are normally not sold with capacity ratings. The reason for this is that the capacity of an alkaline battery is strongly dependant on the load (digital camera load, remote control load, etc.). Alkaline batteries can come in different sizes (i.e. AA, AAA, C, D).

Lithium-ion (Li-Ion) - Are a type of rechargeable battery commonly used in consumer electronics. They are currently one of the most popular types of battery for portable electronics, with one of the best energy-to-weight ratios, no memory effect and a slow loss of charge when not in use.

Lithium Polymer (Li-Poly) - Are rechargeable batteries which have technologically evolved from lithium ion batteries. The energy density of Li-poly batteries is over 20% higher than that of a classical li-ion battery and approximately three times better than Ni-Cd and Ni-MH batteries. Although they are yet to be as widely used.

Nickel Cadmium (Ni-Cd) - Is a popular type of rechargeable battery for portable electronics using the metals nickel (Ni) and cadmium (Cd) as the active chemicals. Ni-Cd batteries have a niche market in the area of cordless and wireless telephones, emergency lighting and power tools. Ni-Cd batteries should be stored discharged. Do not overcharge, as the excessive overheating will damage battery. Remove it from the device and store it in a cool, dry, clean place. If the battery will not be in use for a month or longer then recharge it after the storage period.

Nickel Metal Hydride (Ni-Mh) - Is a type of rechargeable battery similar to a nickel cadmium (Ni-Cd) battery but has a hydrogen-absorbing alloy for the anode instead of cadmium. A Ni-Mh battery can have 2 to 3 times of an equivalent Ni-Cd and the memory effect is not as significant. The discharge rate is strongly affected by the temperature at which the batteries are stored. Interchangeable with most Ni-Cd batteries.

Sealed Lead Acid (SLA) – The oldest type of battery and are used in applications in which the low energy-to-weight ratio may in fact be considered a benefit since the battery can be used as a counterweight (i.e. automobiles, fork lifts, boast, etc.).



Battery Terms


Ampere-hour (abbreviated as Ah) – Is a unit of electric charge. One Ampere-hour is equal to 3600 coulombs (Ampere-seconds). This indicates the amount of electric charge that passes either terminal of the battery when it provides one Ampere of current flow for one hour. The commonly seen milliampere-hour (mAh) is equal to 3.6 coulombs. However, in reality, the available capacity of a battery depends on the rate at which it is discharged.

Anode – An anode is an electrode through which current flows into a polarized electrical device.

Battery - A device that stores chemical energy and makes it available in an electronic form.

Battery Charger – Is a device used to put energy into a cell or rechargeable battery by forcing an electric current through it.

Battery Life – The amount of time a battery will last can be calculated like this - t=C/I (t) is the discharge time in hours, (C) is the battery’s current capacity rating and (I) is the current draw from the battery.

Cathode – Is an electrode through which current flow out of a polarised device.

Cycle – When a charged battery is discharged and then recharged.

Memory Effect – In electrical batteries, also known as lazy battery effect, is an effect observed in some rechargeable batteries that causes them to hold less charge.

Rechargeable Battery – Are batteries that can be restored to full charge by the application of electrical energy.

Smart Battery – Is a method to monitor a rechargeable battery pack, initiated by Duracell and Intel. A special integrated circuit in the battery pack monitors the battery and reports information to the SMBus.

Voltage – The difference of electrical potential between two points of an electronic circuit, expressed in volts.

Watt-hour (Wh) – Is a unit of energy. It is commonly used in the form of the kilowatt-hour (kWh) which is 1000, what-hours.



Battery Lifetime


Even if never taken out of the original package, disposable (or "primary") batteries can lose two to twenty-five percent of their original charge every year. This rate depends significantly on temperature, since typically chemical reactions proceed more rapidly as the temperature is raised. This is known as the "self discharge" rate and is due to non-current-producing chemical reactions, which occur within the cell even if no load is applied to it. Batteries should be stored at cool or low temperatures to reduce the rate of the side reactions. For instance, some people make a practice of storing unused batteries in their refrigerators to extend battery lifetime, although care should be taken to ensure the batteries do not freeze. Extremely high or low temperatures will reduce battery performance.
Rechargeable batteries self-discharge more rapidly than disposable alkaline batteries; up to three percent a day (depending on temperature). Due to their poor shelf life, they shouldn't be left in a drawer and then relied upon to power a flashlight or a small radio in an emergency. For this reason, it's a good idea to keep a few alkaline batteries on hand. Ni-Cd Batteries are almost always "dead" when you get them, and must be charged before first use.
Most NiMH and NiCd batteries can be charged several hundred times. Also, they both can be completely discharged and then recharged without their capacity being damaged or shortened. Automotive lead-acid rechargeable batteries have a much harder life. Because of vibration, shock, heat, cold, and sulfation of their lead plates, few automotive batteries last beyond six years of regular use. Automotive starting batteries have many thin plates to provide as many amps as possible in a reasonably small package, and are only drained a small amount before being immediately recharged. Care should be taken to avoid deep discharging a starter battery, as the recharging process melts a small amount of the lead from the plates. When holes form in the plates it results in less surface area for the chemical reaction, which results in less measured voltage. Leaving a lead-acid battery in a deeply discharged state for any length of time allows the sulfate to become more deeply adhered to the plate, making sulfate removal during the charging process difficult. This can result in less available plate surface and the resulting lower voltage, shortening the battery's life. "Deep-Cycle" lead-acid batteries such as those used in electric golf carts have much thicker plates to aid their longevity. The main benefit of lead-acid is its low cost, the main drawbacks are their large size and weight per a given capacity and voltage. Lead-acid batteries should never be discharged to below 20% of their full capacity as internal resistance will cause heat and damage when attempting to recharge them. Deep-cycle lead-acid systems often use a low-charge warning light or a low-charge power cut-off switch to prevent the type of damage that will shorten the battery's life.
Special "reserve" batteries intended for long storage in emergency equipment or munitions keep the electrolyte of the battery separate from the plates until the battery is activated, allowing the cells to be filled with the electrolyte. Shelf times for such batteries can be years or decades. However, their construction is more expensive than more common forms
Rechargeable and disposable batteries

Various batteries (clockwise from bottom left): two 9-volt, two "AA", one "D", a cordless phone battery, a camcorder battery, a 2-meter handheld ham radio battery, and a button battery, one "C" and two "AAA", plus a U.S. quarter, for scale


From top to bottom:Two button cells, a 9 volt PP3 battery, a AAA battery, a AA battery, a C battery, a D battery, a large 3R12
From a user's viewpoint, at least, batteries can be generally divided into two main types—rechargeable and non-rechargeable (disposable). Each is in wide usage.
Disposable batteries, also called primary cells, are intended to be used once and discarded. These are most commonly used in portable devices with either low current drain, only used intermittently, or used well away from an alternative power source. Primary cells were also commonly used for alarm and communication circuits where other electric power was only intermittently available. Primary cells cannot be reliably recharged, since the chemical reactions are not easily reversible. Battery manufacturers recommend against attempting to recharge primary cells, although some electronics enthusiasts claim it is possible to do so using a special type of charger. [citation needed]
By contrast, rechargeable batteries or secondary cells can be re-charged after they have been drained. This is done by applying externally supplied electrical current, which reverses the chemical reactions that occur in use. Devices to supply the appropriate current are called chargers or rechargers.
The oldest form of rechargeable battery still in modern usage is the "wet cell" lead-acid battery. This battery is notable in that it contains a liquid in an unsealed container, requiring that the battery be kept upright and the area be well-ventilated to ensure safe dispersal of the hydrogen gas which is vented by these batteries during overcharging. The lead-acid battery is also very heavy for the amount of electrical energy it can supply. Despite this, its low manufacturing cost and its high surge current levels make its use common where a large capacity (over approximately 10Ah) is required or where the weight and ease of handling are not concerns.
A common form of lead-acid battery is the modern wet-cell car battery. This can deliver about 10,000 watts of power for a short period, and has a peak current output that varies from 450 to 1100 amperes. An improved type of lead-acid battery called a gel battery (or "gel cell") has become popular in automotive industry as a replacement for the lead-acid wet cell. The gel battery contains a semi-solid electrolyte to prevent spillage, electrolyte evaporation, and out-gassing, as well as greatly improving its resistance to damage from vibration and heat. Another type of battery, the Absorbed Glass Mat (AGM) suspends the electrolyte in a special fibreglass matting to achieve similar results. More portable rechargeable batteries include several "dry cell" types, which are sealed units and are therefore useful in appliances like mobile phones and laptops. Cells of this type (in order of increasing power density and cost) include nickel-cadmium (NiCd), nickel metal hydride (NiMH), and lithium-ion (Li-Ion) cells.


History


The battery was invented over two hundred years ago, but although the first ones were a great sensation in scientific circles, they were too crude and underperforming for serious practical use. Later batteries provided more reliable currents and saw widespread use in industry in stationary devices, particularly in telegraph networks where, in the days before electricital distribution networks, they were the only practical source of electricity.[1] It was only with the invention of dry cell batteries—which did not spill and could be used in any orientation—near the end of the 19th century that portable electronics finally took off.

 

 

 

 

FAQ

Q: How long should my batteries last?

Under standard conditions, the life of a battery is anywhere from 500 to 800 charge-discharge cycles. A decrease in the battery’s running time is the best indication that it is time for a new battery.

Q: Can you explain the difference in Battery Chemistries?

Nickel Cadmium is the most popular type of rechargeable battery, although it tends to suffer from “memory effect” (see below). It has a high rate of energy discharge, meaning that it is low maintenance with high performance. Nickel Cadmium can deliver even power until nearly all of the battery has been used.

Nickel Metal Hydride is the most advanced commercial rechargeable battery. Nickel Metal Hydride batteries last 40% longer than Nickel Cadmium batteries. This battery is generally much more environmentally friendly than Nickel Cadmium, as well.

Lithium Ion batteries do not suffer from the “memory effect” at all (see below). These batteries have twice the energy of Nickel Metal Hydride, although they weigh 33% less. This is especially nice for portable items, such as laptops and camcorders.

Q: What is the memory effect and how does it effect the performance of my battery?

Battery performance and runtime is impaired by a phenomenon called “memory effect”. Basically, this means that if a battery is repeatedly only partially discharged before recharging, the battery will “forget” that it can further discharge. The best way to prevent this situation is to fully charge and discharge your battery on a regular basis.

Q: My new battery is not working, what do I need to do to get it to charge?

Don’t worry. There is nothing wrong with your battery. Your battery will arrive to you in a discharged condition. Therefore, it must be charged in order for it to work. We recommend that new batteries should be charged and discharged two to four times in order to allow them to reach their capacity.

Q: How can I increase the battery life and its performance?

There are several things that you can do to ensure the maximum production from your battery:

·         Never leave your battery in its charger for more than 24 hours. Doing so will shorten the life of your battery.

·         Break in your new batteries. The best way to do this is by fully charging and discharging your new battery several times in order to reach its maximum capacity.

·         Keep your batteries clean. Clean dirty batteries with a cotton swab and alcohol. A clean battery will ensure a good connection between your battery and its device.

·         Do not leave your battery dormant. Generally, a battery should be used every two to three weeks.

Q: How do you properly store a battery?

Batteries should never be left in direct sunlight or in extreme temperatures (below 30 degrees Fahrenheit or above 100 degrees Fahrenheit). They should always be stored in a cool and dry place and should be fully charged before being stored for long periods of time.

Q: Will my device work if I use a battery brand that is different than the original brand of my device?

Due to technological advancements, replacement batters or “after market” batteries will often last longer than the original equipment manufacturer (OEM) batteries that cam with your device

Q: How can I recycle my battery?

Please call the RBRC at 800.8.Battery to find the nearest recycling center to you.