Lithium-Ion and Other Cell Chemistries 79 >ŝĚ ĂŶ ůĞĐƚƌŽůLJƚĞ ^ĞƉĂƌĂƚŽƌ ŶŽĚĞ ĂƚŚŽĚĞ Figure 5 Lithium-ion cell components. LFP is one of the most common chemistries in automotive applications due to its having a high power capability and relatively low cost. This means that it can accept a regenerative braking charge and can provide an acceleration discharge very quickly. The other reason that LFP is frequently used is due to its relatively low cost. In relation to some of the other more rare materials used in lithium-ion cells, iron phosphate is quite common and low cost. Another reason that LFP has gained a high level of usage is that is has been deemed a “safer” chemistry than others.
However, this is somewhat of an inaccuracy. All lithium-ion chemistries have similar failure modes; it is only a matter of at what temperature they fail. In this case, as LFP has lower energy density than the other chemistries on the market and that means that there is less energy to discharge in the event of a failure. However, it is fair to say that LFP is more tolerant of abusive conditions such as overcharging the cell and high temperatures. With the introduction of production EVs, lithium NMC chemistries have begun to gain a strong foothold due to its higher energy density and higher voltage.
Depending on the combi- nation of materials, it is also sometimes referred to as nickel cobalt manganese (NCM) if there is a higher percentage of cobalt than manganese in the chemistry. NMC shows a relatively high nominal voltage of about 3.6–3.8 V per cell and has a one of the highest energy densities in a production cell today of between 140 and 180 Wh/kg in production applications with some chemistries exceeding 200 Wh/kg. LCO is most commonly used in handheld electronics such as cell phones, cameras, and laptop computers. While LCO offers generally higher energy density and long cycle life, it