Batteries Overview

What Is a Battery?

A battery is a type of device that stores chemical energy, which one can activate and use by turning that chemical energy into electrical energy. The batteries all contain a positive terminal and a negative terminal. The term for the positive terminal is the anode, and the term for the negative terminal is the cathode. Today, people use batteries in countless places. They are in our vehicles, flashlights, phones, cameras, and many other electrical devices. If you do not have to plug a device in to use it, then it has some type of battery power supply.

Many different types of batteries exist and are on the market, and each has different uses. It is important to understand what all of these batteries are and what they do, as well as how they work.

Batteries are an essential part of our lives today, and they can provide quite a few advantages and benefits. Batteries, both primary and secondary batteries, allow people to have more freedom with all of their devices, for example. It is possible to take phones, computers, and more out of the office and home and into the field. This helps to make the world more productive.


How Does a Battery Work?

Batteries have several parts. We’ve already established that they have the anode and the cathode, the positive and negative ends. They also have electrolytes in them. The chemicals in the battery cause a chemical reaction in the anode, and it begins to build up electrons. This causes something of a conflict between the cathode and the anode, and the electrons want to rearrange themselves. The chemical reactions that happen inside of a battery cause the electrons to build up at the anode, or the negative end of the battery. This creates an electrical difference between the anode and the cathode. The electrons become unstable, and they want to rearrange themselves in an attempt to relieve the difference. In order to do this, the electrons begin to repel one another in an attempt to go to an area that has fewer electrons. In the battery, this means they need to go to the cathode, and they try to travel through the electrolyte to get there. This electrochemical reaction is what creates the energy that we get from the batteries.

However, they can’t because the circuit is open. This means the battery is not emitting any energy, even though it wants to. When the circuit closes, by creating a conductive path – such as inserting a battery into a device and turning it on – the electrons can flow. This is what powers the devices. Batteries do not last forever though. The chemical reaction in the battery weakens, and that is when the batteries will actually die.


What Is the Difference Between Primary Batteries and Secondary Batteries?

Some batteries are only good for a single use. The chemical reaction weakens to the point that they no longer provide power, and then you need to dispose of them and replace them with new batteries. These single-use batteries have another name – primary batteries. Some of the most common types of primary batteries are the typical alkaline batteries used in portable radios and flashlights. In fact, most of the portable devices can take these sorts of batteries.

Secondary batteries are rechargeable. This means they can be charged and discharged many times. The restoration of the charge happens by reversing the current. Instead of drawing power, they actually accept the delivered power from an external electrical source and store it. Once the charge of the secondary battery is full, it can then go back into use. A substantial number of these sorts of batteries are in use today. They include the batteries in phones, laptops, MP3 players and similar devices.

Secondary batteries, in addition to their use in all of the aforementioned devices, are useful for many types of toys, videogame controllers, PDAs, camcorders, cameras, motor drives, and power tools. The secondary batteries are a wonderful choice for devices and applications that drain batteries quickly. A great example of this is found in the smartphones that people use today. Since people are on their phones so often throughout the day, they drain them of their battery power on a daily basis. Having rechargeable batteries for those devices is essential.



What Type of Battery Cell Exist?

A number of different types of battery sell types are available for different purposes and functions today.

  • Cylindrical Cell – The cylindrical cell is popular for both primary and secondary batteries. They cylinders are common, relatively easy to create, and has the capability to withstand high internal pressures while maintaining shape and function.
  • Button Cell – Button cells are in use in smaller devices that cannot fit a cylindrical cell. It is possible to attain the proper voltage by stacking the cells. These were highly popular for a time, but fell out of fashion. They are in use in some areas today, and you can find them in watches, car key alarms, hearing aids, and similar devices.
  • Prismatic Cell – The prismatic cell first came to use in the early 90s. They are thinner than cylindrical cells, but they have a greater capacity and power than the button cells. Some of the places these are in use today include laptops and cell phones.
  • Pouch Cells – The pouch cell is a very different type of battery. It utilized foil tabs welded to an electrode with positive and negative terminals. These are not readily available, as each manufacturer creates cells for their specific applications. The pouch cells, while many say they are safe, can swell, and there is a chance of puncturing the foil, which can cause damage to a device using it.

One of the other things to know about battery cells is that there are both wet and dry cells. The wet cells have a liquid electrolyte. Another name for this is a flooded cell. A dry cell makes use of a paste electrolyte instead. These batteries will only use enough moisture to ensure a current flow.


What Is Considered the Battery Cell Performance?

The battery cell performance is simply how well the battery performs in different conditions. Performance factors include how long the battery lasts. Different types of batteries will have different load cycles, over charge cycles, and lifetimes. Some of the things that will affect the cell performance include the current drain, the temperature, and the internal chemistry of the battery.


How Is the Capacity and Discharge of a Battery Defined?

The capacity of a battery is the amount of electrical charge it is able to deliver at its rated voltage. If the battery has a larger electrode, it will naturally have a greater capacity. Therefore, smaller cells have a lower capacity, even if it has the same internal chemistry as a larger cell. You measure the capacity in amp-hours, or A-h.


What Is the Battery Lifetime?

The term battery lifetime refers to how long the battery will last. With all batteries, the capacity drops over time, and other factors can reduce the capacity, including dropping temperatures. Usage will naturally decrease the battery life as well, and higher usage can drop the capacity quickly. An example would be a smartphone that you use only for talking and occasional texting. The battery can last for a long time. However, turning up the brightness, watching videos, and playing games will drain the battery very quickly.

With secondary batteries, such as those in the aforementioned smartphone, it is possible to recharge the battery to bring up the capacity and to get more usage out of it. However, over time, even these will diminish to the point that the device will not work without a constant connection to an electrical source.


What Is Self-Discharge of a Battery?

Over time, batteries can self-discharge. Disposable primary batteries will generally lose between 8% and 20% of their charge each year while storing them at room temperature. This is the self-discharge rate, and over the course of a couple of years of storage, the batteries would essentially be useless. Keeping extra batteries on hand can be a good idea, but it is not necessarily a great option to keep batteries around for too long. Keeping the batteries at slightly lower temperatures can help to reduce their discharge rate slightly.

Rechargeable batteries will self-discharge as well, and they do so even faster than alkaline batteries will. They will lose about 10% in the first 24hrs, and then about 10% every month thereafter.


What Is Considered Corrosion of a Battery?

Corrosion of a battery occurs when the internal parts begin to fail and wear away. As batteries age, they will often begin to deteriorate, especially when they are in a device. This can cause leakage, which can actually damage the device. You will notice this more with replaceable batteries than with rechargeable types, but it can happen with any battery. Car batteries will often corrode as well. If you notice any corrosion on a battery, it is important to remove the battery carefully, dispose of it properly, and clean the device before replacing it with a new battery.


How Is the Charge and Discharge Speed of a Battery Determined?

Determining the charge and discharge speed of a battery can be difficult to accomplish because there are so many different battery sizes, types, and capacities available. Some of the things that one must consider when determining the charge and discharge speed include the physical components of the battery, the size of the cell, and the usage.

Some types of batteries, such as the NiCd cells are even more difficult to determine because of something called the “memory effect”. This means that they show a decrease in capacity simply because you are using the battery a certain way. If you only use the battery for two hours and then recharge, it will become accustomed to working for two hours, which will throw off the speed of charge and discharge while in use.


What Is Overcharging of a Battery?

Overcharging a battery is easy to understand. Unfortunately, it is also easy to do, especially if there are no indicators to let you know the charge is full. When you charge a battery too much, there is a chance of damaging the battery, even to the point of rendering it useless. Some devices may have safeties to prevent this from occurring, but it is not a good idea to take the risk.


How Do You Best Store Batteries?

When storing batteries, you will want to keep them at lower temperatures, as mentioned earlier. This helps to reduce the rate at which they discharge. Keeping them in the refrigerator is a good idea, as it can slow the reactions in the batteries. This will help to increase the life of some batteries, such as alkaline batteries, by about 5%. Some battery manufacturers, including Duracell, do not recommend refrigeration.

Keep the batteries in a safe and dry place as well. In addition, make sure that no children or pets can get to the batteries, as they do pose some dangers, which we will discover in the next section.


Why Are Batteries Considered Hazards?

Most of the time, batteries are entirely safe, and there is no danger in using them. However, because of the chemical reactions taking place within them, and because nothing is 100% safe, it is important to take note of some of the different types of risks that batteries can present.

  • Leakage – Some types of batteries will begin to leak. They could corrode and leak or a puncture could cause the contents to leak. These chemicals can be dangerous to people and animals.
  • Explosion – In some cases, such as when trying to recharge a primary battery, there is a chance of explosion. Car batteries may explode if a large current passes through the battery because of a short circuit as well. Overcharging a battery may cause this to happen as well.
  • Toxic Materials – Batteries often have toxic materials in them, such as lead and mercury, which can be extremely dangerous. It is important to dispose of the batteries properly when you’re through using them. Do not simply throw them into the trash.
  • Swallowing – Swallowing batteries, such as the button cell batteries, is extremely dangerous, which is why it is so important to watch children around batteries. They can lodge in the throat or the chemicals could leak into the digestive system.


What Type of Batteries Exist?

  • Automotive Batteries – The automotive batteries are the ones in cars, trucks, motorcycles, and other vehicles.
  • Non-Rechargeable Batteries – Primary batteries such as these include the AAA, AA, and similar batteries commonly used for things such as flashlights, remote controls, and similar items.
  • Rechargeable Batteries – Secondary batteries are common in MP3 players, smart phones, laptops, and a number of other devices.


Nickel Cadmium Batteries (NiCd)

NiCd batteries, first invented in 1899, feature a nickel hydroxide rod inside of them that acts as the cathode. The cadmium acts as the anode in these batteries, and they are separated by electrolyte acid. NiCd batteries are one of the most common types of batteries used today, including 9-volt, AAA, AA, C, and D. These are rechargeable batteries, and one of the benefits is that they tend to charge quickly. They are useful for powering many different types of devices including medical equipment, power tools, cameras, and remote controls.


Lead-Acid Batteries

The most common type of lead-acid battery is the car battery. They are starting batteries and provide an initial burst of power as a means to start an engine. In addition to being starting batteries, lead-acid batteries can also be deep cycle batteries. These are common on campers and boats, where they will power trolling motors or winches. They offer the low and steady power needed for those operations.


Nickel-Metal Hydride NiMh

NiMh batteries are rechargeable batteries. The chemical reaction that takes place in the batteries is similar to that of NiCd batteries. The negative electrodes utilize a hydrogen absorbing alloy rather than cadmium. One of the biggest benefits of these batteries though is that their capacity is between two and three times that of the NiCd batteries.

When charging an NiMh battery, use a smart battery charger to avoid overcharging, which is a danger with these types of batteries.


Lithium Ion Batteries

First entering the commercial market in 1991, these batteries generate electricity via the movement of lithium ions that travel between the cathode and the anode. The batteries are very small and lightweight, and they are in use with many computers, as well as phones. They are secondary batteries that are easy to recharge by plugging the device that contains the battery into an outlet.


Specialty Batteries

Many types of specialty batteries are available as well, and they serve unique purposes, and generally have unique sizes. Small batteries could power a number of small accessories, including watches, pedometers, and glucose meters. Larger specialty batteries might power emergency lighting. These can provide power for emergency and exit lighting.


How Are Batteries Maintained?

Maintaining batteries is important to help ensure the life of the battery. Keeping the batteries stored properly and in a dry, cool place – not necessarily in the refrigerator – is a good idea. It is also important to check the batteries you have in your devices periodically, as they may be getting to the point of corroding. Replace batteries regularly, even before they wear out fully, so you do not have to worry about this.

When it comes to secondary batteries, recharge them only when they really need it. Let the charge wear down and then plug it in to recharge. Otherwise, you could suffer from the memory effect mentioned earlier in the article, which reduces the life of the battery and is difficult to correct.