The modern world runs on electricity, and batteries are among the most common tools that we use to store it. They are vital for keeping our phones and other devices in good working order. It is important that we understand the things that we use in our daily lives, but relatively few people understand how batteries get made. The process is surprisingly simple because batteries only have a few important parts, so anyone can learn to understand the basics with just a few minutes of study.
A battery is a collection of electrochemical cells, which can use a chemical reaction to create an electric charge. Those cells are fairly simple, but they do have a few vital components. These parts are the cathode, the anode, and the separator that goes between them.
The cathode is a chemical mixture that provides ions with a positive charge, while the anode provides ions with a negative charge. The separator is usually a layered piece of paper soaked in electrolytes. That keeps the anode and the cathode from mixing, which would neutralize them and cause them to stop functioning.
The construction process starts with the cathode. In most cases, the cathode is made up of manganese dioxide, carbon in the form of graphite, and an electrolyte. Battery factories receive all those ingredients in bulk, and then mix them together in the right proportions to create the cathode blend. After that blend has been thoroughly mixed, the workers convert it into a granular form and compact it into hollow cylinders. A single battery will always have at least one of them, but bigger batteries can use several.
Those cylinders then go into cans made of nickel-plated steel to form the cathode. Some factories produce these cans on their own, while others order them from other producers. In either case, the workers will put an indentation on top of the loaded can and cover that indentation with a sealant to make sure that none of the chemicals can leak out of the cathode.
The separator is the next part to go in. It is a simple sheet of layered paper, like the material that other operations use to make paper cups. The workers soak it in the electrolyte solution and insert it along the bottom of the cathode.
The workers will then add the anode to the can below the separator. The workers make the anode filling out of potassium hydroxide, powdered zinc, and a few other materials. It does not need to be shaped because it naturally forms a paste that can go directly into the can. This will fill most of the can, but there will be a little space left at the top.
That battery can produce power, but nearly every manufacturer will add a few extra components to make their batteries safer and more efficient. A brass spike through the middle of the can helps with efficiency. The workers weld that into place and use the combination of a seal and a cap to keep everything in place.
That makes for a functional battery, but it still needs a label. Adding that label, which will provide technical details about the battery’s performance and the manufacturer’s logo, is the last step. After that, the battery is ready to get packaged, sold, and put to good use!
Battery technology is old and has largely standardized. That means that while manufacturers do have some room for variation to differentiate themselves, the core design will be the same and there won’t be huge difference between brands. That forces the companies to compete on quality rather than design, so testing is a core part of the process. Most companies will test the batteries at every stage of production to make sure that everything is exactly as it should be.
Longer and more specialized testing is also common, such as tests to see how well the batteries hold up to storage under various conditions. Every company will use a different set of tests to make sure that their production processes can turn out an excellent product and to figure out how they can make better batteries in the future. The end result is a constant series of little changes to this broad process.