Batteries are everywhere in our lives. Not only in the products we buy, but in our electronics projects! It’s not always clear when we should use which time, or what even makes one type of battery different from another. In this tutorial we’re going to cover the different types of batteries and talk about some of the applications we might choose them for.
Batteries serve really one main purpose: They store potential energy for use at a later time. The process is usually chemical in nature but not always. If you wind up a rubber band it too will store potential energy. Some data centers and large industrial plants have begun relying on super large flywheels for storing potential energy!
It’s important to understand that batteries only store DC or direct current energy. They cannot store AC or alternating current. Devices such as a UPS (uninterruptible power supplies) contain complex transformers and switching circuits to convert DC stored in batteries to AC.
Batteries have three basic components in the their construction: Anodes, cathodes, and electrolytes. Let’s briefly discuss what these components are and their general functions.
The anode of a battery (commonly referred to as the negative electrode) is the the portion of the battery that stores up electrons. We discussed this concept in our tutorial on capacitors.
The cathode of a battery (commonly referred to as the positive electrode) reacts with the anode to create a potential difference in energy. These two forces naturally want to equalize. However, the electrolyte resides between the anode and the cathode and prevents this from happening.
When the battery is connected to a circuit, it provides a path (generally through your project!) for the electrons to flow from the anode back to the cathode!
RELATED: How Capacitors Work
Two Major Types of Batteries
There are many types of batteries and battery construction. All of these batteries can be grouped into two major categories: Primary and Secondary. So let’s start with those!
Primary Batteries – One Time Use
Primary batteries are considered one time use batteries. These batteries are not rechargeable! Their construction uses materials that do allow for reversing their electrochemical reactions. Primary batteries were at one time the most common type of battery before technology reached a tipping point for rechargeable battery technology.
Primary batteries still have many applications today. There are times where a device will never need to be recharged and will be disposed (maybe even before the battery is fully discharged). You might find a primary battery in a missile or bomb used in military applications. No need to recharge something that will be destroyed!
Secondary Batteries – Rechargeable
Secondary batteries are considered rechargeable batteries. These batteries are constructed with materials that allow for reversing their electrochemical reaction by applying a current to them from a charging device.
Secondary batteries are used in all kinds of gadgets and gizmos, including your smartphone, portable gaming devices, and remote controls.
Types of Batteries
From the two major types of batteries, we can break down into all of the most common types. Let’s list them off and go over some of their features and drawbacks.
Alkaline batteries are primary cell batteries. They are the most popular type of non-rechargeable battery. You’ll find alkaline batteries in all types of shapes and sizes, including AAA, AA, C, D, coin cells, and many others.
Alkaline batteries are have some great characteristics including having a long shelf life. Alkaline batteries can be store for years without losing charge. They are considered very safe, somewhat environmentally friendly in composition (though they still often wind up in landfills), and they’re voltage levels are very stable.
The main drawback of alkaline batteries is that due to their chemical makeup, they are only suitable for low current applications. This is why you generally see alkaline batteries used for remote controls and small devices such as flashlights, but never used in applications such as car batteries.
Lead-acid batteries are a secondary cell battery (rechargeable) and are generally used in heavy-duty applications such as automotive car batteries. Due to their construction materials (lead and liquid acid) they are most often extremely heavy and not viable for most portable applications.
Most often used in high-current applications, such as power storage for solar farms, automotive starters, uninterruptible power supplies, and marine. Lead-acid batteries are also very affordable to manufacture, are highly recyclable, and a low energy to weight ratio. However, since they are filled with liquid or gel acid, they can be dangerous if they leak and produce toxic fumes in enclosed environments. Non-sealed batteries used indoors must generally have an exhaust gas fan installed.
Fun fact: Lead acid batteries were one of the first rechargeable batteries ever developed!
Nickel–cadmium battery (commonly referred to as a Ni-Cad battery) rechargeable secondary cell battery which is manufactured using nickel-oxide-hydroxide and metallic-cadmium. Ni-Cad batteries when first introduced were applauded for their ability to keep up with the steady voltage levels output by alkaline batteries and were seen as the obvious choice for their replacement.
However, Ni-Cad batteries have one major drawback. They suffer from memory loss. Not memory loss like Alzheimer’s but loss of storage capacity over time. This happens commonly when a partially discharged battery is recharged. After a time the battery forms a memory and will not discharge past this memory point. For this reason a Ni-Cad battery typically performs best if it is fully discharged before recharging it.
Ni-Cad batteries, though falling in popularity are still found in may rechargeable devices such as walkie-talkies, portable FM radios, and flashlights.
Nickel-Metal Hydride Batteries
Next up as we continue to explore types of batteries, its time to talk about the nickel-metal hydride battery (commonly referred to as an Ni-MH battery). These are also a secondary cell rechargeable battery. Construction and composition are very similar to Ni-Cad batteries, with one major difference. The negative electrode is made of nickel-metal hydride instead of cadmium.
This composition gives the Ni-MH battery some serious advantages over its Ni-Cad brethren. First, Ni-MH does not suffer from the memory loss issues associate with Ni-Cad batteries. This makes them last longer, and lowers maintenance and discharge cycle problems. Second, Ni-MH has about three times the storage capacity of Ni-Cad in the same form factor, resulting in more powerful batteries in smaller sizes.
Lithium-Ion batteries (commonly called Li-On batteries) are also a secondary cell rechargeable battery. Li-On batteries are one of, if not the most popular types of batteries in use today. They are packed with fantastic features that make them suitable for many types of electronics devices. They tend to hold a charge when sitting with little to no discharge over time, unlike Ni-Cad or Ni-MH which need to be continually refreshed.
You’ll find Li-On batteries in smartphones, laptops, and many other portable devices where high power in a small size is important. Li-On batteries used in these devices is generally lithium-cobalt oxide (LiCoO2) and is considered very safe.
Selecting the Right Battery for your Application
With all of these different types of batters (some we didn’t even mention), how do you decide which battery to use in your application? That’s generally going to come down to making three decisions:
- Cost – Let’s face it. Many times we’re limited by what we can afford. You’ll need to select a battery that won’t break your bank. This is why many R2-D2 builders select Lead-acid batteries over Li-On and just deal with the massive weight problems and dangers of leaking acid.
- Safety – Which brings us to safety! You’re not likely going to want to store a bank of lead-acid batteries in your kid’s room. And if you do, you’ll probably wind up in lots of hot water. Select a battery that can safely be used in the intended application. A lead-acid battery in an outdoor buggy would be perfectly safe.
- Life – You’ll want to select a battery that will last long enough for your project. A drone that can only fly for 3 minutes wouldn’t be very useful.
If you have any questions, leave a comment below and we’ll do our best to help you out!