We tend to think of batteries from our experiences interacting with them. Most of us know what an AA or AAA battery looks like and how we use it everyday. We’re also familiar, though less tangibly so, with lithium-based batteries such as those in our phones and other devices. Some of us can even scale up those ideas to imagine a battery in a car.
Batteries work on the same principals, no matter what their internal chemistry. Every battery has an anode, a cathode, and a connection between those which allows ions to travel between them. The AA batteries in your flashlight work this way and so do the large, heavy, and more complex batteries in your Tesla or Mach-e.
The chemistry in the middle of the anode and cathode (the electrodes) is where batteries in electric vehicles differ the most. Shapes for containment of the electrodes and chemistry within can vary a lot. Some are the familiar cylindrical shape of the AA, C, and D cells we interact with regularly. They are just packed into very large battery packs in a dense configuration to make up the battery pack for the EV. Other cells are shaped like pancakes, rectangular pouches, etc. Whatever their external design, these batteries are all using the same internal principals to work. Some shapes allow for more compact storage, better thermal management, or fewer connections between cells. Each shape has different advantages and disadvantages.
Nearly all EV cells are made up of one of two chemistry types, both of which use lithium as a cathode and graphite as an anode. The most common of those two is an NMC or NMCA design. Nickel-manganese-cobalt (NMC) cells and nickel-manganese-cobalt-aluminum (NMCA) cells have high energy density, making them pound-for-pound the most energy dense option for electric vehicles right now. They are also a high fire hazard if they oxidize from a short circuit or severe impact. Most EVs sold in North America and Europe are of these chemistries.
The other most common is LFT, or lithium-iron-phosphate chemistry. These iron-phosphate cells have much lower energy density (less power per weight), but are more stable than are NMC/NMCA designs. These cells are most common in China.
In other electrified vehicles, like plug-in hybrids and standard gasoline-electric hybrids, can be any of the above. Or they can be nickel-metal hydride (NiMH). These are simpler, longer-lasting batteries with high degrees of safety. But they are not very energy dense and they are expensive to produce. For smaller-use applications like a PHEV or hybrid, though, they are a good option and have been used by companies like Toyota and General Motors for decades.
More recently, solid-state batteries have become a new buzz term. These are made up of a solid ceramic material as an electrolyte rather than liquid. This makes them more stable, cheaper, and less polluting to manufacture. BMW, Ford, Toyota, and others are both working on these types of batteries and are likely to have them ready for use in some vehicles as early as 2025.
As battery-powered vehicles progress and technologies improve, we can expect to see more innovations. Especially in the batteries that power these vehicles.
Aaron is an automotive journalist living in Wyoming, USA. His background includes technology, mechanics, commercial vehicles, and new vehicle evaluations. Aaron is a member of several automotive media groups and writes for many well-known publications.