The term “lithium-ion” is everywhere these days, but most people don’t understand what it means other than it’s in our batteries. It’s easy to equate that lithium-ion technology powers cars, toys, and mobile phones, but the chemistries in each are vastly different. There are seven different commercially available lithium-ion chemistry types, each with its own unique properties and uses.
Society now relies on lithium-ion to power more of our lives than ever before, but there’s still fear and confusion surrounding the technology and many lingering questions. What are the different types of lithium-ion chemistries? What are they used for? Is it safe?
A battery by any other name
Using “lithium-ion” to describe a battery is similar to using “fuel” to describe combustible gas and liquids. “Fuel” could describe gasoline, diesel, natural gas, propane, and other similar gases or liquids. However, most of us understand that you wouldn’t put diesel in a gasoline engine. Just as each oil-based fuel suits a different application, each lithium-ion chemical formula suits a different application.
Unlike fuels, though, there’s a lack of widespread understanding of the types of lithium-ion chemistries. This lack of knowledge makes it challenging for consumers to make informed buying decisions and increases their confusion and mystery.
Batteries are traditionally named based on their chemistry, like the lead-acid batteries that start our cars or the zinc batteries that power our flashlights. But, when the first lithium-ion chemistry came to market in the 1990s, the makers named it after the unique physics the battery operates on rather than the past’s traditional chemical nomenclatures.
The seven types of lithium-ion
There are seven basic types of lithium batteries on the market today: Lithium Iron Phosphate, Nickel Manganese Cobalt, Nickel Cobalt Aluminum, Lithium Titanium Oxide, Lithium Manganese Oxide, Lithium Cobalt Oxide, and Lithium Nickel Cobalt Oxide.
Each unique chemical makeup results in distinctive properties and ideal uses. These include energy density, intake and energy release speeds, how well they hold energy over time, the stability of their chemical makeup, and much more.
One of the most common chemistries is lithium iron phosphate (LiFePO4), most commonly known as LFP. As the most consumer-accessible lithium-ion chemistry, LFP is often used in toys like RC cars and hoverboards, drop-in replacements for traditional lead-acid batteries, and in a vast number of consumer electronics devices.
Many DIY articles and videos that discuss working with lithium-ion assume that LFP is the only type of lithium-ion chemistry. Many people don’t know that LFP batteries have lower power density and are not the strongest chemistry available although both flexible and useful. While great for smaller applications, LFP’s relatively low energy-density limits its usefulness for more robust applications like vehicles.
Nickel Manganese Cobalt (NMC) chemistry is generally two to three times more energy-dense than LFP technology. NMC is the dominant chemistry in the automotive industry, alongside Nickel Cobalt Aluminum (NCA). No mainstream domestic automakers are using LFP chemistries in their automobiles for the powertrain.
The safety of lithium-ion
When it comes to advanced energy storage, safety is the top priority. Along with these advancing technologies, the way we view something as “safe” also needs to evolve. For example, the U.S. Fire Administration estimated in 2016 that of all the fires that fire departments respond to, 1/8 are highway vehicle fires. That amounts to over 200,000 cars (most being internal combustion) catching fire each year, and yet the vast majority of Americans drive them every day.
To date, gasoline is about 30 times more energy-dense than the best lithium-ion chemistry available on the market, but we heavily rely on it for transportation with little concern. Safety isn’t defined by chemistry alone: The overall system design is what determines any system’s safety and performance, which is why we are all comfortable driving around with 14 gallons of potentially explosive fuel under our seats. The same system-based safety design is true of lithium-ion chemistries.
Because it’s so commonly found in the market, consumers are conditioned to believe that LFP batteries are the safest lithium-ion option. However, as mentioned before, safety isn’t just about chemistry. One of the most extensive recalls in American history happened in 2016 with the battery failure of LFP-powered hoverboards. The poorly-designed batteries overheated to the point that they caught fire and posed a significant risk to unsuspecting consumers.
Products like the recalled hoverboards were poorly-designed and unable to contain and manage the battery’s chemistry safely. It’s the overall system’s design, not only the energy chemistry, that determines product safety. As long as lithium-ion products are properly designed, they’re just as safe, if not safer, than non-lithium-ion products.
Continued education is Key
As the world continues shifting towards lithium-ion as an advanced energy solution for all power applications, ongoing education on the technology’s chemistry, uses and limitations are essential. In the same way, consumers know they shouldn’t put gasoline in their grills or propane in their cars; we will learn that NMC and NCA are standard to robust applications like cars or backup power. In contrast, LFP is more useful in lower voltage applications like consumer electronics.
Educating people on the specifics of lithium-ion technology is the first step towards creating a world where safe, reliable power is available to an informed consumer base.
The views and opinions expressed in this article are the author’s own, and do not necessarily reflect those held by pv magazine.
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