A common misconception is that lithium-ion batteries for electric vehicles and energy storage are the same. However, electric vehicle batteries and lithium-ion batteries have very different energy storage requirements.
While they are both good at what they do, it's crucial to understand their differences. This can help you discover which type of battery is best for your specific situation. There is no one-size-fits-all approach when it comes to using lithium-ion batteries.
What are lithium-ion batteries used for energy storage made of?
Energy storage applications require batteries that can recharge reliably day after day and have high reliability, long life, and safety. Energy density usually isn't that important because these batteries can't provide the energy to move their own weight, like an electric car.
Our energy storage lithium-ion batteries use cathodes composed of lithium iron phosphate (LFP) to meet these requirements well. However, this results in a higher weight per unit of energy, making them less suitable for electric vehicles. Lithium iron phosphate batteries create fewer interactions between the electrolyte and cathode than more energy-dense chemistries, helping the battery last longer and improve safety.
What are lithium-ion batteries for electric vehicles made of?
Electric cars need to pack as much energy into their batteries as possible compared to their weight. That's because the battery's energy is needed not only to power the car, but also to power the car itself. We can measure the energy density of a battery in units of watt hours per volume (liters) or per weight (kilograms).
Most electric vehicle batteries are made slightly differently than lithium iron phosphate batteries. Electric car makers rely on lithium-ion batteries made of nickel and cobalt to create cathodes to power their vehicles. They use these compounds because they are a denser form of energy. This facilitates common propulsion scenarios in electric vehicles. These batteries are called NMC batteries because of their composition.
Lithium-ion batteries for electric vehicles have an organic liquid electrolyte inside. This electrolyte reacts strongly with oxygen, especially at higher temperatures. This is often why you hear about explosions or other potential problems due to thermal runaway. They are not as stable as LFP batteries.
What is the difference between lithium-ion batteries for energy storage and lithium-ion batteries for electric vehicles?
Both LFP and NMC batteries are high-quality cells that can deliver large amounts of power. However, there are some key differences that make them great at specific tasks. Understanding these differences can help determine which type of battery to use in a given situation.
Positive component
Both types of lithium-ion batteries use a cathode to generate electricity. However, batteries used for energy storage use LFP, while electric vehicle batteries use NMC because of their larger energy density. Due to their higher energy density, these batteries are an excellent solution for any mission that requires propulsion, such as electric vehicles.
oxygen bond
Both types of batteries require an electrolyte to react with oxygen. However, the oxygen bonds in NMC cells are much looser than those in LFP cells. As a result, these batteries are more susceptible to thermal runaway and, in some cases, can explode, especially in environments with elevated temperatures. Overall, lithium iron phosphate batteries are much less likely to experience thermal runaway and are generally a safer option.
Battery aging process
NMC batteries operate at 3.7 volts, while lithium iron phosphate batteries operate at 3.2 volts. Higher voltage results in faster interaction between NMC and battery electrolyte. Therefore, as the battery ages, battery damage increases. Because lithium iron phosphate batteries have a lower voltage, they enjoy the benefits of cathode stability, which extends the battery's life.
Furthermore, LFP is a larger molecule compared to NMC. Because lithium iron phosphate is a larger molecule, lithium iron phosphate batteries can expand and contract more easily as the battery expands and contracts as it charges and discharges. Over the life of lithium iron phosphate, this can mean thousands of charge and discharge cycles. Being able to expand and contract easily is very important.
What is the operating voltage of energy storage lithium-ion batteries?
Lithium-ion batteries are designed with energy storage in mind and operate at 3.2 volts per cell. This is lower than the voltage of the NMC batteries used to power cars. This improves the stability of the cathode, giving the battery a longer life expectancy and less chance of thermal runaway. It's great for storing energy you'll need later.
This 3.2 volt voltage is also a good match for older battery technologies such as lead-acid voltage. This makes our LFP batteries ideal for storage in systems operating on standard 12, 24 or 48 volts.
