[Automotive Technology Trends] Why Are Car Batteries Different? Part 2: Advanced Overview In our previous article, we summarized that car batteries vary by model. This article dives deeper into the large batteries used in electric vehicles. Currently, two types are mass-produced: LFP and NMC. Their differences lie not in manufacturing methods, but in design priorities. Meanwhile, solid-state batteries are still under development. Why are lithium-ion batteries specifically chosen for EVs? Because they offer several times the energy storage per unit weight compared to lead-acid batteries, enabling sufficient electricity to power the vehicle. Within lithium-ion technology, two distinct paths have emerged: LFP prioritizes cost and lifespan, while NMC is optimized for long-range driving. Both are already in mass production. LFP stands for Lithium Iron Phosphate. Its cathode uses iron and phosphate instead of nickel and cobalt. According to the International Energy Agency (IEA), over half of all EV batteries deployed globally in 2025 were LFP, with an average cost per kilowatt-hour at least 40% lower than NMC. LFP also boasts a longer lifespan—typically 3,000 to 5,000 charge cycles, compared to NMC’s 1,000 to 2,500. Even daily full charging imposes less stress on LFP cells. Additionally, LFP cells ignite at approximately 270°C, significantly higher than NMC’s ignition range of 150–210°C. This does not mean fires are impossible, but rather that they are far less likely to occur. Models using LFP include the Tesla Model 3 and Model Y base variants, the Ford Mustang Mach-E Standard Range (73 kWh), and the 2027 Chevrolet Bolt (65 kWh). NMC stands for Nickel Manganese Cobalt. It offers higher energy density than LFP, allowing greater range for the same weight. Cell-level energy density ranges from approximately 90–205 Wh/kg for LFP and 150–300 Wh/kg for NMC. However, NMC is more expensive, has a shorter lifespan, and degrades faster when repeatedly charged to 100%. For this reason, NMC-equipped vehicles typically recommend daily charging only up to 80%. This is precisely why long-range trims use NMC. LFP’s drawbacks are weight and cold-weather performance. To achieve the same range, an LFP pack must be heavier or larger. The difference becomes more pronounced in cold temperatures: LFP can lose over 30% of its range in sub-zero conditions, while NMC typically loses only 15–25%. In regions with long winters like Michigan, battery preheating and temperature management during charging are as critical as range itself. Vehicles equipped with battery preheating before charging exhibit significantly faster charging speeds in winter than those without. From a diagnostic perspective, LFP’s flat voltage curve is critical. Between 20% and 80% state of charge (SOC), LFP cell voltage remains stable around 3.2–3.3V. Estimating remaining capacity based solely on voltage is effectively unreliable in this range. The Battery Management System (BMS) must combine Coulomb Counting (current integration) with cell modeling and calibrate using full-charge and end-of-discharge reference points. When assessing battery health, one cannot rely on voltage alone; SOC, State of Health (SOH), temperature, and cell-to-cell variation must all be considered together. If range is reduced despite normal voltage readings, the first items to investigate are SOC, SOH, and cell imbalance—not voltage. Solid-state batteries represent the next step forward. They replace liquid electrolytes with solid electrolytes. CATL has developed a sulfide-based solid-state cell prototype at 20Ah capacity and set an energy density target of 500 Wh/kg—still a goal, not a production specification. CATL aims for limited production by 2027 and mass production around 2030 but rates the technology maturity at level 4 out of 9. Guangzhou-based Greater Bay Technology (GBT) announced it began mass production of solid-state cells on a 1 GWh line on October 13, 2026; however, the vehicle models to use them remain unconfirmed, and key metrics such as first-generation cell cost, lifespan, and charging speed have not been disclosed. Solid-state technology remains under active development and is still a technology to watch.In summary, in drive batteries, LFP is now the standard; for longer-range applications, watch NMC, and beyond that, solid-state batteries. The battery question has thus shifted from “Which battery is better?” to “What are you trying to achieve with the battery?” LFP is ideal for vehicles with mostly city driving; NMC suits those with frequent long-distance travel; solid-state batteries remain a technology without a published price tag yet. Terminology Notes: LFP (Lithium Iron Phosphate): A lithium-ion battery using iron and phosphate in the cathode. It is inexpensive, long-lasting, and thermally stable, but has lower energy density. NMC (Nickel Manganese Cobalt): A lithium-ion battery using nickel, manganese, and cobalt in the cathode. It offers high energy density but is more expensive and has a relatively shorter lifespan. Solid-state battery: A battery using a solid electrolyte instead of a liquid one. Still not in mass production. Energy density: The amount of electrical energy stored per unit of weight or volume, measured in Wh/kg. BMS (Battery Management System): A device that monitors cell voltage, current, and temperature, and controls charging and discharging. SOC (State of Charge): The remaining charge in the battery expressed as a percentage. SOH (State of Health): A measure of the battery’s current performance relative to its original condition when new. Coulomb Counting: A method of estimating charge level by integrating current over time. IEA (International Energy Agency): An international organization that researches energy policy and publishes statistics. Photo: CATL LFP prismatic cell Photo: Aeroid, Wikimedia Commons, CC BY-SA 4.0