How Do Batteries Work? Your In-Depth Guide

by | Educational

Alessandro Volta accidentally created the first battery in 1800. He was trying to prove to a fellow scientist that it was not necessary to use animal tissue to produce an electric current. Volta was successful in winning his debate and then some. The unforeseen invention of the electrochemical cell brought Volta many honors. Yet, he remained a very modest man.   

After his passing, Volta’s face appeared on stamps as well as the 10,000 Italian Lire banknote, which left circulation in 2002. Volta’s name lives on as others commemorated his work by naming the volt after him, a unit we use to measure the force of electric currents  

But what is it that Volta discovered that made the battery work? In this article, we’ll dive deep into answering frequently asked questions, including: how do batteries work, what are they made of, what types of batteries are there today, and what problems do we have with batteries? 

How Do Batteries Work? 

Batteries are one of those things that the majority of us take for granted. They’re just a regular part of everyday life that, for the most part, go unseen while they store energy and perform their magic. Think flashlights, cell phones, remote controls, hearing aids, car batteries, and even electric cars.   

But have you ever stopped to really try and understand how these indispensable products that provide us with portable, instant energy actually work? Batteries are self-contained power packs that store chemical energy and convert it into electrical energy. The process is known as electrochemistry. To explain the process of how batteries work in more depth, let’s get into the details of what batteries are made of. 

What Are Batteries Made Of? 

What Are Batteries Made Of | Image Charging iPhonesource

A battery usually will consist of a group of electrochemical cells. There are two different types: voltaic (also referred to as galvanic) and electrolytic.   

  1. Voltaic or Galvanic Cells: These acquire energy from spontaneous redox reactions. With these cells, chemical energy turns into electrical energy.  
  1. Electrolytic Cells: These acquire energy from an external electron source such as an alternating current (AC) power source or a direct current (DC). With these cells, electrical energy turns into chemical energy. 

Let’s look at an example of the two types of cells. When something with a rechargeable battery like your cell phone or tablet is on the charger, the battery is functioning as an electrolytic cell. However, while you’re using your electronic device, the battery is working as a voltaic cell.  

A standard battery cell requires the following three elements to produce electricity: 

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  • Anode: This is the battery’s negative electrode or negative terminal and is the oxidation site. It’s also the positive electrode in an electrolytic cell. We commonly use metals like lithium and zinc as the anode in the form of a paste found inside a part called the separator. We use the separator to prevent short circuits by keeping the negative and positive electrodes apart. 
  • Cathode: This is the battery’s positive electrode or positive terminal. It’s also the negative electrode in an electrolytic cell. The cathode consists of silvery matte rings made of metallic oxides like graphite and manganese dioxide. 
  • Electrolyte: This is the chemical substance separating the anode and the cathode. It’s the chemical catalyst in the form of a gooey paste or liquid used in between the electrodes to make the battery conductive. It does this by providing the ion transport mechanism between the anode and cathode of the cell. This is where the battery’s chemical energy transforms into electrical energy. Potassium hydroxide, sodium, and chloride are the major electrolytes.  

The two different metals (the anode and cathode) are attached to the battery at opposite ends from each other. This allows a chemical reaction to occur between the electrolyte and the metals, allowing more electrons to release through one metal than the other.  

A positive charge develops in the metal that receives a more significant amount of electrons. A negative charge then forms on the opposite side. Then, when a wire, or external circuit, connects the two battery ends to each other, the flow of electrons moves through the wire, balancing the electrical charge and producing an electric current.  

The final step is to introduce what we call an electrical load. This is anything that needs electricity to operate. Let’s use a flashlight as an example. When you put the batteries into the flashlight and flip the switch on, you create a circuit. This circuit connects its light bulb to the wire, allowing electrical energy to flow through the wire and the bulb as electrons pass through the battery’s negative end, through the wire, the light bulb, and back to the battery’s positive end. 

Are Batteries Capacitors?  

Batteries Capacitorssource

Energy storage has come a long way over the years. Today, two of the main places we store energy are batteries and capacitors. And while they’re very similar, they are not the same. Let’s look at the similarities and differences between the two. 

What Are the Similarities Between Batteries and Capacitors? 

Here are the main similarities between batteries and capacitors:  

  • The stored energy produces an electric potential, commonly known as voltage.  
  • The electric potential generates a flow of electrons, called an electric current. 
  • The electric current can create electrical energy to power components within a circuit.  

Engineers will choose whether to use a battery or capacitor for their product based on the circuit design and its function. Sometimes, they go with a combination of the two. However, that doesn’t mean the two are completely interchangeable. 

What Differences Are There Between Batteries and Capacitors? 

Here are the main differences between batteries and capacitors:  

  • When comparing a battery and a capacitor of the same volume, the battery has thousands of times more capacity to store energy than the capacitor.  
  • Batteries are dependable, supplying energy in a steady stream.  
  • Capacitors can frequently provide bursts of energy quicker than batteries.  
  • Capacitors store an electric field of energy, making them rechargeable. In contrast, batteries store their energy in a chemical field that often cannot recharge. 
  • Batteries tend to lose their capacity for charge holding, but this does not happen with capacitors.  
  • Simple capacitors are usually made with nontoxic materials making it safe to discard them.  

Do Batteries Generate Alternating Current (AC) or Direct Current (DC)? 

Alternating current (AC) is a flow of electrons that switches directions regularly, many times a second. The majority of our household appliances run on AC power. For example, the majority of our microwaves, coffee pots, dishwashers, televisions, and even our HVAC systems run on alternating current. However, since battery electrons flow only in one direction, batteries generate direct current (DC). Many portable devices, such as flashlights, cell phones, and mp3 players, run on the DC power provided by batteries. 

What Are the Different Types of Batteries? 

Batteries Types of in a Bucketsource

Not all batteries are equal. Different types of batteries are made with other chemicals and work with various chemical reactions. Let’s take a look at seven of the more common types of batteries.  

1. Alkaline Battery  

Duracell® and Energizer® are two popular brands that make alkaline batteries. These are our standard AA, AAA, C, D, and 9-volt batteries. The electrodes in these batteries are manganese oxide and zinc. The electrolyte is an alkaline paste of either potassium or sodium hydroxide.  

2. Lead Acid Battery  

Lead acid batteries are what we use for car batteries and photovoltaic solar power systems. The electrodes in these batteries are lead and lead oxide, while the electrolyte is a strong acid.  

3. Lithium Battery  

Cameras with flash bulbs use lithium batteries, but otherwise, most lithium batteries you come across are coin or button-cell-shaped for things like watches and other small, low-power devices. While they don’t give much power, you can stack lithium batteries to get a higher voltage. All lithium batteries use metallic lithium as the anode and are non-rechargeable. For this reason, they’re also called primary lithium metal batteries. The cathode will vary, but the most common lithium metal batteries typically use manganese dioxide. 

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4. Lithium-Ion Battery  

Cell phones and other portable electronic equipment typically are powered by a lithium-ion battery, which is rechargeable. Additionally, lithium-ion batteries have become popular to use for electric vehicles and larger-scale smart grids. For the anode, lithium-ion batteries use lithium-carbon compounds. The cathode uses lithium-metal oxides. 

5. Nickel-Cadmium or NiCad Battery  

We find nickel-cadmium batteries, which are rechargeable batteries, in power tools as well as many of our small household appliances. The electrodes in these batteries are nickel-hydroxide and cadmium, while the electrolyte is potassium hydroxide.  

6. Nickel Metal Hydride (NIMH) Battery 

Also a rechargeable battery, nickel-metal hydride batteries are used in devices with a high-drain factor, like digital cameras and video game controllers. These batteries use positive electrodes of nickel oxyhydroxide, and the negative electrodes use a hydrogen-absorbing alloy. 

7. Zinc-Carbon Dry Cell or Standard Carbon Battery 

If you purchase a product that has “batteries included,” there’s a good chance that means it has zinc-carbon batteries due to their low cost. Generally, the electrodes use zinc metal and a carbon rod surrounded by manganese dioxide. The electrolyte is made of a paste of ammonium chloride.  

What Are Some Problems With Batteries?

Battery Problems | Image of iPhone on Firesource

No product is perfect. There will always be the occasional defective piece. However, some products have more issues than others. Here are some of the main problems that consumers tend to have with batteries:  

  • Batteries can catch fire or even explode: Although the occurrence is infrequent, if a battery is defective and the electrodes end up touching each other, the battery could short circuit causing extreme heat, fire, or an explosion. 
  • Batteries can’t get wet: After water enters a battery, it’s near impossible to get it out since a battery’s safety vent keeps liquids from leaking out of the batteries. Water in a battery could cause it to malfunction. Quickly and properly dispose of batteries that have gotten wet. 
  • Batteries can freeze: It has to be pretty darn cold outside, but if you live in an area that experiences harsh, cold winters, then beware. A battery can freeze at around 10 degrees below Fahrenheit if it’s only half-charged. 
  • Batteries are bad for the environment: Batteries that aren’t disposed of properly can end up with buildup and corrosion, allowing their chemicals to contaminate our land and water. These battery chemicals are not only bad for our ecosystems, but they also get into our drinking water and the air we breathe. Not to mention, lithium batteries can potentially cause landfill fires and contribute to global warming. The good news is that batteries are recyclable. And it’s super easy. Energizer® has a site to help you find places near you to recycle batteries. You can also try one of these websites: 

What Types of Batteries Do You Use? 

Now that we’ve answered the big question, “how do batteries work,” it’s time to have a little fun with your newfound knowledge. Try taking a walk around your house to see how many different types of batteries you use. Then, for more great information on commonly-used household products, check out our article about light bulbs to learn how you can save big money. 

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