An electric vehicle battery is a rechargeable battery that powers the electric motors in battery electric vehicles (BEVs) or hybrid electric vehicles (HEVs). These batteries are usually lithium-ion batteries, which are designed to have a high power-to-weight ratio and high energy density. Compared to liquid fuels, most battery technologies today store less energy per unit of weight. This can make vehicles heavier or reduce the distance they can travel before needing to recharge.

Li-NMC batteries, which use lithium nickel manganese cobalt oxides, are the most common type in electric vehicles. Lithium iron phosphate batteries (LFP) are becoming more popular, with 41% of the global market share for BEVs in 2023. LFP batteries are heavier than Li-NMC batteries but are less expensive and more environmentally friendly. Some car companies are now using sodium-ion batteries, which do not require rare minerals.

The battery is a major part of an electric vehicle’s cost and environmental impact. As the industry grows, ensuring ethical and responsible battery supply chains has become an important international issue. Reducing the use of mined cobalt, which is also used in fossil fuel refining, is a key research goal. New battery chemistries, such as solid-state batteries, are being tested in laboratories and can store more than 800 watt-hours per kilogram.

In 2019, the cost of electric vehicle batteries dropped by 87% per kilowatt-hour. In 2023, demand for electric vehicle batteries exceeded 750 gigawatt-hours. These batteries have much larger capacities than traditional automotive batteries used for starting, lighting, and ignition in gasoline-powered cars. In 2023, available electric vehicle models had battery capacities ranging from 21 to 123 kilowatt-hours, with an average of 80 kilowatt-hours.

Electric vehicle battery types

As of 2024, lithium-ion batteries (LIBs), including Li-NMC, LFP, and Li-NCA types, are the most common type used in battery electric vehicles (BEVs). In 2023, the total global production capacity of these batteries reached nearly 2000 GWh, with 772 GWh used for electric vehicles. Most of this production occurs in China, where capacity increased by 45% in 2023. Lithium-ion batteries are preferred for EVs because they have high energy density and long cycle life. These batteries were first developed for use in laptops and consumer electronics. Recent EVs use new lithium-ion variations that trade some energy and power for improved fire resistance, environmental benefits, faster charging, and longer lifespans. For example, lithium-ion cells with single-wall carbon nanotubes (SWCNTs) show greater strength, which helps prevent battery damage and extends their lifespan.

Lithium nickel manganese cobalt oxides (NMC) offer strong performance and have been the global standard in BEV production since the 2010s. However, mining the minerals needed for NMC batteries causes environmental harm. Traditional NMC batteries have drawbacks, such as sensitivity to temperature, poor performance in cold weather, and reduced performance over time. Traditional lithium-ion batteries can also catch fire if damaged or charged incorrectly due to unstable electrolytes, oxidized metal oxides, and unstable anode layers. Early lithium-ion batteries could not charge or power vehicles in extremely cold conditions, but heaters can help in some climates.

Lithium iron phosphate (LFP) batteries are less expensive, safer, and more sustainable than NMC batteries. They do not require manganese or cobalt. Since 2023, LFP has become the leading battery type in China, but it is used in less than 10% of EVs in Europe and North America. LFP batteries are also widely used for storing energy in power grids.

Lithium titanate (LTO) batteries are known for their safety, as they are less likely to overheat and work well in a wide range of temperatures. These batteries can last for over 10,000 charge-discharge cycles and charge quickly. However, they have lower energy density compared to other lithium-ion batteries.

Sodium-ion batteries avoid using critical materials. Sodium, found in salt water, is abundant and inexpensive. In early 2024, Chinese companies began producing sodium-ion batteries for small EVs, bikes, and three-wheelers. For example, models like the JAC Yiwe Sehol E10X and JMEV EV3 Youth Edition started using these batteries. By 2026, sodium-ion batteries will be used in mass-produced cars, such as the Changan Nevo A06.

Other battery types are being developed:
– Solid-state batteries may offer high energy density and better safety.
– Lithium-sulfur batteries could meet high performance needs.
– LMFP batteries are a type of LFP battery that includes manganese in the cathode.

In the 20th century, most EVs used flooded lead-acid batteries because they were reliable, widely available, and inexpensive. These batteries powered early EVs like the 1996 EV1. There are two main types of lead-acid batteries: starter batteries for cars and deep-cycle batteries for vehicles like forklifts or golf carts. Deep-cycle batteries are also used in recreational vehicles but require special charging methods. Discharging below 50% can shorten their lifespan. Flooded batteries need regular checks for electrolyte levels and water replacement. EVs with lead-acid batteries can travel up to 130 km (81 miles) per charge.

Nickel-metal hydride (NiMH) batteries are a mature technology. While less efficient than lead-acid batteries, they have higher energy density (30–80 W·h/kg). When used correctly, NiMH batteries can last a long time, as shown by their use in hybrid cars and the first-generation Toyota RAV4 EVs, which still work well after 100,000 miles (160,000 km) and over a decade. However, NiMH batteries perform poorly in cold weather below -20 °C and require careful charging. GM Ovonic produced the NiMH batteries used in the second-generation EV-1. Early NiMH-EVs could travel up to 200 km (120 miles) per charge.

The sodium nickel chloride or "Zebra" battery was used in EVs from 1997 to 2012. It uses a molten sodium chloroaluminate (NaAlCl₄) salt as the electrolyte and has a specific energy of 120 W·h/kg. These batteries must be heated to operate, so cold weather does not affect their performance but increases heating costs. Zebra batteries can last for several thousand charge cycles and are non-toxic. However, they have low power output (<300 W/kg) and require heating the electrolyte to about 270 °C (518 °F), which uses energy and creates storage and safety challenges.

Other types of rechargeable batteries used in early EVs include:
– Nickel-cadmium batteries.
– Nickel-iron batteries used in the Detroit Electric.
– Lithium vanadium oxide batteries used in the Subaru prototype G4e.

Battery architecture and integration

• Cell to Module (CTM) – battery cells are placed into modules, then into a battery pack
• Cell to Pack (CTP) – battery cells are placed directly into a battery pack without using modules
• Cell to Chassis (CTC) – battery cells are placed into the frame or chassis of a vehicle; the batteries may help support the structure or add strength
• Cell to Body (CTB) – battery cells are placed into the body of a vehicle

Supply chain

During the first stage, materials are mined in various parts of the world, such as Australia, Russia, New Caledonia, and Indonesia. China plays a major role in most of the following steps. After the materials are refined in factories, battery manufacturing companies purchase them, make batteries, and assemble them into packs. Car companies then buy these packs and install them in vehicles. To reduce the environmental impact of this process, the supply chain is focusing more on sustainability. This includes reducing the use of rare-earth minerals and improving recycling efforts.

The manufacturing process of EV batteries has three main stages: materials manufacturing, cell manufacturing and integration. These stages are shown in a graph with colors gray, green, and orange. This graph does not include the production of cell hardware, such as casings and current collectors. In the materials manufacturing stage, the active material, conductivity additives, polymer binder, and solvent are mixed first. Then, they are coated onto the current collectors for the drying process. The methods used to make active materials depend on the type of electrode and battery chemistry.

Cathodes often use transition metal oxides, such as lithium nickel manganese cobalt oxides (Li-NMC) or lithium iron phosphates (LFP). Graphite is the most common material for anodes. Recently, some companies have started using silicon mixed anodes (e.g., Sila Nanotech, ProLogium) and lithium metal anodes (e.g., Cuberg, Solid Power).

In general, producing active materials involves three steps: materials preparation, processing, and refinement. Schmuch and others have discussed these steps in more detail.

During the cell manufacturing stage, prepared electrodes are shaped for packaging in cylindrical, rectangular, or pouch formats. After filling the electrolytes and sealing the cells, the battery cells are carefully cycled to form a protective layer called the SEI on the anode. These batteries are then assembled into packs for use in vehicles.

For electric vehicles (EVs), the end of life depends on factors like the owner’s willingness to continue using the EV as its range decreases, the condition of other vehicle parts, and whether the vehicle is involved in a crash. However, in repurposing studies, end of life is often defined as when a battery’s capacity drops to 80% of its original level. This definition comes from the U.S. American Battery Consortium, which states that end of life occurs when the battery’s capacity or peak power capability at 80% depth of discharge is less than 80% of its rated value. One waste management method is to reuse the battery pack. Repurposing the pack for stationary storage helps extract more value from the battery while reducing environmental impact over its lifetime.

Battery degradation during EV operation can vary based on temperature and charging/discharging patterns. Each battery cell may degrade differently. Currently, the battery management system (BMS) can track the state of health (SOH) at the pack level but not the individual cell level. Engineers can reduce degradation by improving thermal management systems. Electrochemical impedance spectroscopy (EIS) can be used to check the quality of the battery pack.

Disassembling battery modules and cells is expensive and time-consuming. The module must be fully discharged, and the pack must be taken apart and reconfigured to meet the power and energy needs of the second life application. A refurbishing company can sell or reuse the energy from the discharged module to lower costs. Robots are being used to make the dismantling process safer.

Battery technology is not transparent and lacks standardization. Since battery development is central to EVs, it is hard for manufacturers to label the exact chemistry of cathodes, anodes, and electrolytes on the pack. Also, the capacity and design of cells and packs change yearly. Refurbishing companies must work closely with manufacturers to get timely updates on this information. Governments can help by setting labeling standards.

Battery costs have decreased faster than expected. This may make refurbished units less appealing than new batteries in the market.

Despite these challenges, there have been successful examples of second-life applications using EV batteries. These batteries are often used in stationary storage projects for purposes like peak shaving or storing energy from renewable sources.

Although extending battery life through second-life applications is helpful, EV batteries will eventually need to be recycled. Currently, recyclability is not a major focus for battery manufacturers. In 2019, only 5% of EV batteries were recycled. However, recycling is important for several reasons. It helps reduce reliance on limited supplies of nickel, cobalt, and lithium in the future. Recycling also reduces environmental harm by minimizing mining impacts, energy use, and greenhouse gas emissions. Xu and others predicted that without recycling, lithium, cobalt, and nickel could exceed known reserves in the future. Ciez and Whitacre found that recycling batteries can reduce greenhouse gas emissions from mining.

BEV technologies lack clear recycling frameworks in many countries. This makes using BEVs and other battery-powered equipment more energy-intensive, increasing CO₂ emissions, especially in countries with limited renewable energy resources.

Efforts worldwide are promoting recycling technology development. In the U.S., the Department of Energy’s Vehicle Technologies Offices (VTO) has two initiatives focused on recycling innovation and practicality. The ReCell Lithium Recycling RD center brings together three universities and three national labs to create efficient recycling methods. Notably, the ReCell center developed a direct cathode recycling method. VTO also offers a battery recycling prize to encourage American entrepreneurs to find solutions to current recycling challenges.

Recycling EV batteries helps recover valuable materials like lithium, cobalt, nickel, and rare-earth elements. This reduces the need for new mining, conserves natural resources, and lowers the environmental impact of battery production by reducing mining effects, energy use, and greenhouse gas emissions.

To better understand the lifecycle of EV batteries, it is important to analyze emissions from each phase. Using NMC cylindrical cells as an example, Ciez and Whitacre found that about 9 kg of CO₂ per kilogram of battery is emitted during raw material processing and battery manufacturing under the U.S. electricity grid. The largest share of emissions came from material preparation, which accounted for over 50% of total emissions. If NMC pouch cells are used, total emissions increase to nearly 10 kg of CO₂ per kilogram of battery, with material manufacturing still contributing over 50% of emissions. Refurbishing adds little to the lifecycle emissions, but recycling emits a significant amount of greenhouse gases, as noted by Ciez and Whitacre.

Battery cost

Between 2010 and 2024, the average cost of batteries dropped by 90% because of improvements in battery technology and manufacturing methods. Batteries make up a large part of an electric vehicle’s (EV) total cost, often as much as 30-40% of the vehicle’s price. Over time, battery costs have decreased steadily due to technological progress, larger production volumes, and better manufacturing techniques. Most EV batteries come with warranties that cover a set number of years or miles, showing confidence in their long-term reliability.

The cost of lithium-ion battery packs remains a major challenge for the widespread use of battery electric vehicles (BEVs), especially when comparing their prices to traditional gasoline-powered cars. About 70% of a battery’s total cost comes from the materials used in its cells, with the cathode alone making up 40-45% of that cost. The prices of raw materials like nickel and cobalt often change rapidly, which directly affects the cost of cathode materials and, in turn, the overall battery price.

New models now calculate battery costs based on the prices of raw metals instead of using fixed prices for cathode materials. This method shows how changes in the prices of cobalt and nickel influence the cost of materials like NMC, NCA, LMO, LNMO, and LFP. Using cathodes with higher nickel content, such as NMC811 and NCA, has helped lower material costs by increasing energy storage capacity and reducing the need for cobalt.

Studies show that larger electric vehicles, such as those with a 200-mile range, benefit from lower costs per kilowatt-hour (kWh) because of thicker battery electrodes and better production efficiency. For example, battery pack costs can range from about $545 per kWh for plug-in hybrid electric vehicles (PHEV10) to around $230 per kWh for BEV200 vehicles. These cost reductions are greater than those achieved by improvements in manufacturing alone.

Larger production volumes help lower battery costs, but significant savings slow down after making 200–300 million watt-hours (MWh) of batteries each year. To continue reducing costs, manufacturers may need to build larger factories, improve electrode-making processes, and use equipment more efficiently. Today, the smallest factories that can produce batteries profitably make less than 2 gigawatt-hours (GWh) per year, but future factories may need to produce more than 15 GWh per year to keep costs low and support market growth.

EV parity

One issue is the purchase price, and the other is the total cost of ownership. The total cost of ownership for electric cars is often lower than that of petrol or diesel cars. In 2024, Gartner predicted that by 2027, next-generation battery electric vehicles (BEVs) will, on average, be cheaper to produce than similar internal combustion engine (ICE) vehicles. In China, BEVs are now less expensive than comparable combustion cars. This development is supported by government subsidies in the Chinese market. In the USA, tariffs are used to protect local manufacturers, while in the EU, this approach is still being discussed. These actions may slow progress toward equal costs between electric and combustion vehicles.

The weight of the electric vehicle battery is a major challenge in achieving the same range as combustion vehicles. Diesel and gasoline have more than 50 times the energy density of current EV batteries.

In real-world use, how quickly a vehicle can charge is more important than battery size (see recharging section). Typical EV batteries in passenger cars weigh between 300 to 1,000 kg (660 to 2,200 lb), providing ranges of 150 to 500 km (90 to 310 miles). This range depends on factors like temperature, driving habits, and the type of car.

Even when an electric vehicle has the same range as a typical combustion vehicle, buyers need to be certain that charging stations are widely available and compatible with their vehicles.

As of 2024, electric ships and large planes have shorter ranges than combustion-powered vehicles. To fully electrify shipping, standardized multi-megawatt charging systems are needed. In some cases, such as river shipping, batteries can be swapped instead of recharging. As of 2024, fully electric large planes with a range over 1,000 km are not expected to be available within the next ten years, meaning that for more than half of scheduled flights, equal range cannot be achieved.

Specifics

Battery packs in electric vehicles (EVs) are complex and can be different depending on the company and how the vehicle is used. However, all battery packs use simple mechanical and electrical parts that work together to perform basic tasks.

The individual battery cells inside the pack can have different chemical types, shapes, and sizes, depending on the manufacturer. These cells are connected in series and parallel to reach the needed voltage and current for the pack. Battery packs in all-electric vehicles often have hundreds of cells. Each cell has a standard voltage of 3-4 volts, depending on its chemical type.

To make manufacturing easier, large groups of cells are divided into smaller groups called modules. These modules are then placed into the battery pack. Inside each module, cells are connected with welds to allow electricity to flow. Modules may also include cooling systems, temperature sensors, and other tools. These modules must stay within a safe temperature range to work well. Most modules use a battery management system (BMS) to monitor the voltage of each cell.

The battery pack has a main fuse that limits current during a short circuit. A "service plug" or "service disconnect" can be removed to split the battery pack into two separate parts. When the service plug is removed, the battery terminals no longer carry high electrical risks for workers.

The battery pack also uses relays, or contactors, to control how electricity flows from the pack to the vehicle’s output terminals. Most packs have at least two main relays that connect the battery cells to the positive and negative terminals, which send high current to the motor. Some designs include extra paths for charging the system or powering other parts, each with its own relays. These relays are usually open (not connected) unless needed.

The pack includes sensors that measure temperature, voltage, and current. These sensors work with the battery monitoring unit (BMU) or BMS to collect data and control relays. The BMS also communicates with other parts of the vehicle outside the battery pack.

Batteries in battery-electric vehicles (BEVs) need to be recharged regularly. BEVs can be charged at home from the power grid, solar panels, or public charging stations. Energy for charging comes from sources like coal, hydroelectricity, nuclear power, natural gas, solar panels, and wind.

Fast charging reduces concerns about limited driving range because it shortens the time needed to stop at public stations. Many charging stations now offer direct current (DC) power of 150 kW or more, which can add up to 300 km of range in about 30 minutes. Charging speed depends on the station’s power and the vehicle’s ability to handle it. Charging usually slows when the battery is over 50% full. Typical fast charging ranges from 30 to 80 kW. Charging at home or smaller stations using alternating current (AC) takes several hours. A typical estimate is 15 kWh of energy for every 100 km of travel.

Home charging time depends on the electrical outlet’s power unless special wiring is done. In the U.S., Canada, Japan, and other countries with 120 V electricity, a standard outlet provides 1.5 kW. In countries with 230 V electricity, outlets can provide 7 to 14 kW (single-phase) or 400 V (three-phase). In Europe, 400 V three-phase connections are becoming more common because newer homes often lack natural gas connections due to safety rules.

With proper power supplies, battery life is usually best when charging rates do not exceed half the battery’s capacity per hour ("0.5 C"), meaning a full charge takes two or more hours. Faster charging is still possible for large batteries.

New research shows that heat and fast charging can damage lithium-ion batteries more than age or regular use. On average, an EV battery retains 90% of its original capacity after six years and six months. For example, the battery in a Nissan Leaf degrades twice as fast as a Tesla battery because the Leaf lacks an active cooling system.

A 2024 study in Nature Energy found that EV batteries may last up to one-third longer in real-world use than in laboratory tests. This challenges the idea that lab tests accurately predict battery life in everyday conditions.

Charging power can connect to a car in two ways. The first is through a direct electrical connection, called conductive coupling. This uses special high-capacity cables and connectors to protect users from high voltages. In the U.S., the SAE 1772 connector (IEC 62196 Type 1) is standard. In Europe, the VDE-AR-E 2623-2-2 (IEC 62196 Type 2) is used, which lacks a latch and avoids extra power needs for locking.

The second method is inductive charging, where a "paddle" is inserted into a slot on the car. The paddle and a coil in the car form a magnetic circuit to transfer power. Inductive charging avoids electrocution risks by keeping no exposed wires. It also reduces vehicle weight by moving charging parts outside the car. Some experts argue inductive charging is as safe as conductive methods with proper safety tools.

As of June 2024, there are more than 200,000 charging locations and 400,000 EV charging stations worldwide.

The range of a BEV depends on the number and type of batteries used. The vehicle’s weight, terrain, weather, and driver behavior also affect range, just like in traditional vehicles. EVs with lithium-ion batteries can travel 320–540 km (200–340 mi) on a single charge.

Low temperatures can increase a battery’s internal resistance, reducing range and battery lifespan.

With AC or advanced DC systems, regenerative braking can increase range by up to 50% in heavy traffic.

Research, development and innovation

As of December 2019, billions of euros are planned to be invested globally for improving battery technology.

Researchers have developed design ideas for contactless chargers for battery electric vehicles (BEVs). Inductively coupled power transfer (ICPT) systems use magnetic fields to transfer power efficiently from a charging station (primary source) to one or more BEVs (secondary sources) without direct contact.

Europe plans large investments in the development and production of electric vehicle batteries. Indonesia also plans to produce electric vehicle batteries by 2023 and has invited Chinese companies, GEM and Contemporary Amperex Technology Ltd, to invest in the country.

Electric double-layer capacitors, also called "ultracapacitors," are used in some electric vehicles, such as AFS Trinity's concept prototype. These devices store energy quickly due to their high specific power, which helps keep batteries from overheating and extends their lifespan.

Commercially available ultracapacitors have low specific energy, so no currently produced electric cars use them as the sole energy storage method.

In January 2020, Elon Musk, CEO of Tesla, said that improvements in lithium-ion battery technology have made ultracapacitors unnecessary for electric vehicles.

On May 2, 2022, President Biden announced a $3.16 billion plan to increase domestic battery manufacturing and recycling as part of a larger effort to move the United States away from gas-powered cars to electric vehicles. The Biden administration aims to have half of U.S. automobile production be electric by 2030.

The Inflation Reduction Act, passed on August 16, 2022, provided incentives for clean energy manufacturing, including a $7,500 tax credit for electric vehicles with batteries made in the United States and subsidies for electric vehicle plants. By October 2022, billions of dollars in investment had been announced for over two dozen U.S. battery plants, leading some to call the Midwest the "Battery Belt."