Electric vehicle battery
An electric vehicle battery is a rechargeable battery used to power the electric motors of a battery electric vehicle or hybrid electric vehicle.
They are typically lithium-ion batteries that are designed for high power-to-weight ratio and energy density. Compared to liquid fuels, most current battery technologies have much lower specific energy. This increases the weight of vehicles or reduces their range.
Li-NMC batteries using lithium nickel manganese cobalt oxides are the most common in EV. The lithium iron phosphate battery is on the rise, reaching 41% global market share by capacity for BEVs in 2023. LFP batteries are heavier but cheaper and more sustainable. However, some commercial passenger car manufacturers are now beginning to use a sodium-ion battery completely avoiding the need for critical minerals.
The battery makes up a significant portion of the cost and environmental impact of an electric vehicle. Growth in the industry has generated interest in securing ethical battery supply chains, which presents many challenges and has become an important geopolitical issue. Reduction of use of mined cobalt, which is also required in fossil fuel refining, has been a major goal of research. A number of new chemistries compete to displace Li-NMC with performance above 800Wh/kg in laboratory testing.
, despite more reliance on recycled materials the cost of electric vehicle batteries has fallen 87% since 2010 on a per kilowatt-hour basis.
Demand for EVBs exceeded 750 GWh in 2023. EVBs have much higher capacities than automotive batteries used for starting, lighting, and ignition in combustion cars. The battery capacity of available EV models reached from 21 to 123 kWh in 2023 with an average of 80 kWh.
Electric vehicle battery types
As of 2024, the lithium-ion battery with the variants Li-NMC, LFP and Li-NCA dominates the BEV market. The combined global production capacity in 2023 reached almost 2000 GWh with 772 GWh used for EVs in 2023. Most production is based in China where capacities increased by 45% that year. With their high energy density and long cycle life, lithium-ion batteries have become the leading battery type for use in EVs. They were initially developed and commercialized for use in laptops and consumer electronics. Recent EVs are using new variations on lithium-ion chemistry that sacrifice specific energy and specific power to provide fire resistance, environmental friendliness, rapid charging and longer lifespans. These variants have been shown to have a much longer lifetime. For example, lithium-ion cells containing single wall carbon nanotubes show increased mechanical strength, suppressing degradation and leading to a longer battery lifetime.| Li-NMC | LFP | Li-NCA | Sodium-ion | Lead-acid | |
| global BEV market share | 59% | 40% | 7% | <1% | no data |
| Energy density per ton | 150-275 kWh 150-220 kWh 165 kWh | 80-150 kWh 210 90-160 kWh 135 kWh | 200-260 kWh | 140-160 kWh | 35 kWh |
| Energy density projection | 300 kWh | 260 kWh | >200 kWh | ||
| Price per kWh | 139$ 130$ | 70$ 105$ | 120$ | 80-120€ 87$ | 65-100$ |
| Price projection | 80$ | 36$ | <40€ 40-80$ 8-10$ | ||
| Cycles | 1500 - 5000 | 3000 - 7000 | 4000 - 5000 | 200 - 1500 | |
| Considerable flammability | yes | no | medium | no | yes |
| Temperature range | medium | high | high | medium | |
| Production | >67% China | 100% China | - | - | - |
Lithium-NMC
offer high performance and have become the global standard in BEV production since the 2010s. On the other hand, the exploitation of the required minerals causes environmental problems. The downside of traditional NMC batteries includes sensitivity to temperature, low temperature power performance, and performance degradation with age. Due to the volatility of organic electrolytes, the presence of highly oxidized metal oxides, and the thermal instability of the anode SEI layer, traditional lithium-ion batteries pose a fire safety risk if punctured or charged improperly. Early cells did not accept or supply charge when extremely cold. Heaters can be used in some climates to warm them.Lithium iron phosphate (LFP)
The Lithium iron phosphate battery has a shorter range but is cheaper, safer and more sustainable than the NMC battery. It does not require the critical minerals manganese and cobalt.Since 2023, LFP has become the leading technology in China while the market share in Europe and North America remains lower than 10%. LFP is the dominant type in grid energy storage.
Lithium titanate (LTO)
or lithium-titanium-oxide batteries are known for their high safety profile, with reduced risk of thermal runaway and effective operation over a wide temperature range. LTO batteries have an impressive cycle life, often exceeding 10,000 charge-discharge cycles. They also have rapid charging capabilities due to their high charge acceptance. However, they have a lower energy density compared to other lithium-ion batteries.Sodium-ion
The Sodium-ion battery completely avoids critical materials. Due to the high availability of sodium which is a part of salt water, cost projections are low. In early 2024, various Chinese manufacturers began with the delivery of their first models. Analysts see a high potential for this type especially for the use in small EVs, bikes and three-wheelers.Future types
Several types are in development.- The solid-state battery could offer high energy density and potential safety improvements.
- The lithium-sulfur battery is also expected to meet high performance demands.
- The LMFP battery is a LFP battery that includes manganese as a cathode component.
Legacy types
Lead-acid
In the 20th century most electric vehicles used a flooded lead–acid battery due to their mature technology, high availability, and low cost. Lead–acid batteries powered such early modern EVs as the original 1996 versions of the EV1. There are two main types of lead–acid batteries: automobile engine starter batteries, and deep-cycle batteries which provide continuous electricity to run electric vehicles like forklifts or golf carts. Deep-cycle batteries are also used as auxiliary batteries in recreational vehicles, but they require different, multi-stage charging. Discharging below 50% can shorten the battery's life. Flooded batteries require inspection of electrolyte levels and occasional replacement of water, which gases away during the normal charging cycle. EVs with lead–acid batteries are capable of up to per charge.Nickel–metal hydride (NiMH)
Nickel–metal hydride batteries are considered a mature technology. While less efficient in charging and discharging than even lead–acid, they have a higher specific energy of 30–80 W·h/kg. When used properly, nickel–metal hydride batteries can have exceptionally long lives, as has been demonstrated in their use in hybrid cars and in the surviving first-generation NiMH Toyota RAV4 EVs that still operate well after and over a decade of service. Downsides include finicky charge cycles and poor performance in weather below -20 °C. GM Ovonic produced the NiMH battery used in the second generation EV-1. Prototype NiMH-EVs delivered up to of range.Zebra
The sodium nickel chloride or "Zebra" battery was used in early EVs between 1997 and 2012. It uses a molten sodium chloroaluminate salt as the electrolyte. It has a specific energy of 120 W·h/kg. Since the battery must be heated for use, cold weather does not strongly affect its operation except for increasing heating costs. Zebra batteries can last for a few thousand charge cycles and are nontoxic. The downsides to the Zebra battery include poor specific power and the need to heat the electrolyte to about, which wastes some energy, presents difficulties in long-term storage of charge, and is potentially a hazard.Other legacy types
Other types of rechargeable batteries used in early electric vehicles include- nickel–cadmium
- Nickel–iron battery used in the Detroit Electric
- Lithium vanadium oxide made its way into the Subaru prototype G4e.
Battery architecture and integration
- Cell to Module - battery cells put into modules, than into battery pack
- Cell to Pack - battery cells into battery pack without modules
- Cell to Chassis - battery cells into frame or chassis, batteries maybe used as part of structural integrity or to increase structural strength
- Cell to Body - battery cells into vehicle body
Supply chain
Lifecycle of lithium-based EV batteries
During the first stage, the materials are mined in different parts of the world, including Australia, Russia, New Caledonia and Indonesia. All the following steps are currently dominated by China. After the materials are refined by pre-processing factories, battery manufacturing companies buy them, make batteries, and assemble them into packs. Car manufacturing companies buy and install them in cars. To address the environmental impact of this process, the supply chain is increasingly focusing on sustainability, with efforts to reduce reliance on rare-earth minerals and improve recycling.Manufacturing
There are mainly three stages during the manufacturing process of EV batteries: materials manufacturing, cell manufacturing and integration, as shown in Manufacturing process of EV batteries graph in grey, green and orange color respectively. This shown process does not include manufacturing of cell hardware, i.e. casings and current collectors. During the materials manufacturing process, the active material, conductivity additives, polymer binder and solvent are mixed first. After this, they are coated on the current collectors ready for the drying process. During this stage, the methods of making active materials depend on the electrode and the chemistry.Cathodes mostly use transition metal oxides, i.e. Lithium nickel manganese cobalt oxides, or else Lithium metal phosphates, i.e. Lithium iron phosphates. The most popular material for anodes is graphite. However, recently there have been a lot of companies started to make Si mixed anode and Li metal anode.
In general, for active materials production, there are three steps: materials preparation, materials processing and refinement. Schmuch et al. discussed materials manufacturing in greater details.
In the cell manufacturing stage, the prepared electrode will be processed to the desired shape for packaging in a cylindrical, rectangular or pouch format. Then after filling the electrolytes and sealing the cells, the battery cells are cycled carefully to form SEI protecting the anode. Then, these batteries are assembled into packs ready for vehicle integration.