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Electric Vehicle Battery

BMW Electric-Vehicle Battery_042523A
[BMW Electric-Vehicle Battery]

- Overview

The most common battery technology for electric vehicles (EVs) is lithium-ion. Lithium-ion batteries have become the industry standard because they are lightweight, have high energy efficiency, and perform well in different temperatures. 

Lithium-ion batteries are made up of two electrodes in an electrolyte. The cathodes are made up of lithium plus other metals, most commonly a blend of nickel, manganese, and cobalt (NMC) or nickel, manganese, cobalt, and aluminum (NMCA). New lithium-ion battery-equipped EVs provide 320–480 km (200–300 mi) of range per charge. 

Improvements in battery chemistry, cell design, and manufacturing have made EV batteries lighter, more compact, and longer-range. They also have shorter charge times. 


- Current Developments in EV Battery Technology

Researchers have been improving lithium-ion (Li-ion) batteries to make them more efficient and less expensive. The average cobalt content of EV batteries is expected to decrease by 44% by 2030. Improved pack assembly techniques, like cell-to-pack (C2P) technology, will increase the energy density of cobalt-free Lithium Iron Phosphate (LFP). 

Carbon nanotube electrodes could increase energy storage by three times and battery lifecycle by five times. NAWA says that charging time could be as short as five minutes to get to an 80 percent charge.

Some current developments in EV battery technology include: 

  • Solid-state batteries: These batteries are emerging as the next frontier in EV battery technology. Solids are denser than liquids, meaning the electrolyte takes up less space and battery cells can be smaller.
  • Sodium-ion batteries: Toyota CEO has announced the world's first EV with a sodium solid state battery.
  • Recycling and second-use batteries: Some companies are working on strategies to make batteries still smaller and lighter and, also, faster charging.

Other developments in EV battery technology include: 

  • Silicon anode batteries
  • Lithium-sulfur batteries
  • Fast charging and longevity
  • Wireless charging

- EV Batteries

Most EVs today are powered by lithium-ion batteries, a decades-old technology that is also used in laptops and cell phones. All those years of development have helped drive down prices and improve performance, so today's EVs are approaching the price of gasoline-powered cars and can travel hundreds of miles on a single charge. Lithium-ion batteries are also finding new applications, including electricity storage in the grid, which could help balance intermittent renewables like wind and solar.

EV batteries typically consist of thousands of rechargeable lithium-ion cells connected together to form a battery pack. Lithium-ion batteries are most popular for their cost-effectiveness, offering the best balance between energy storage capacity and price. But there is still a lot of room for improvement. 


- How Do EV Batteries Work?

Each cell in an EV battery pack has an anode (the negative electrode) and a cathode (the positive electrode), separated by a plastic-like material. When the positive and negative terminals are connected (think turning on a flashlight), ions move between the two electrodes through the liquid electrolyte inside the battery. At the same time, electrons from these electrodes travel through wires outside the battery. 

If a battery supplies electricity (for example, the bulb in the flashlight above) - this action is called discharging - then ions flow from the anode to the cathode through the diaphragm, while electrons move through the wire from the negative (anode) to the positive (cathode) terminal to the outside The load provides power. Over time, the battery's energy drains as it powers whatever it's powering. 

However, when a battery is charged, electrons flow in the other direction (from positive to negative) from an external energy source, and the process is reversed: electrons flow from the cathode back to the anode, again adding energy to the battery.

During normal use of a rechargeable battery, the potential of the positive electrode remains greater than that of the negative electrode both during discharge and recharge. On the other hand, the role of each electrode switches during the discharge/charge cycle.

  • During discharge the positive is a cathode, the negative is an anode.
  • During charge the positive is an anode, the negative is a cathode.


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- Battery Raw Materials

With the popularity of EVs, the demand for special raw materials for automobiles, especially batteries, will continue to grow. All predictions indicate that lithium-ion batteries will become the standard solution for electric vehicles in the next decade, so the main substances required will be the chemical elements graphite, cobalt, lithium, manganese and nickel. 

According to estimates from the Fraunhofer Institute for Systems and Innovation (ISI), despite advances in battery chemistry, the weight ratio of lithium in each battery is about 72 g/kg during this period, which is unlikely to be significant. reduce. 

However, the proportion of cobalt may drop significantly from 200 g/kg cell weight to around 60 g/kg. Thus, by 2030, the demand for primary raw materials for automotive battery production should be between 250,000 to 450,000 tons of lithium, 250,000 to 420,000 tons of cobalt, and 13 to 2.4 million tons of nickel.


- EV Battery Charging Time

Reducing battery charging time could also help reduce the size of the battery pack and hence costs of EVs, thereby increasing their adoption. 

The time it takes to charge an electric vehicle (EV) depends on the type of charger and how low the battery level is. Charging times can range from 15 minutes to 24 hours. 

Here are some charging times for different types of chargers: 

  • DC fast chargers: Can charge an EV to 80% in 30–60 minutes
  • Level 2 chargers: Can charge an EV to 80% in 4–10 hours
  • Level 1 chargers: Can take about 19 hours to charge a medium-sized EV
  • 220/240V outlets: Can take 9 hours and 35 minutes to fully charge an EV

Other factors that can affect charging time include: 
  • The size of the battery
  • The speed of the charging point
  • The battery level 


- New Battery Technologies

Academic labs and companies alike are looking for ways to improve the technology -- increasing capacity, speeding up charging times and reducing costs. The goal is to use cheaper batteries, provide cheap storage for the grid, and allow EVs to travel farther on a single charge.

At the same time, concerns about the supply of key battery materials such as cobalt and lithium are driving the search for alternatives to standard lithium-ion chemistries. 

Here are some new battery technologies for EVs: 

  • Graphene batteries: Graphenano is developing batteries that can be recharged in minutes and have an estimated range of 500 miles. Graphenano claims that its batteries can charge and deplete 33 times faster than lithium-ion batteries.
  • Lithium-air batteries: The US Department of Energy's Argonne National Laboratory has developed a lithium-air battery that could increase the range of electric vehicles. The new design could one day replace lithium-ion batteries.
  • Zinc batteries: Scientists have developed a new zinc battery that releases 99.95% of the energy it is charged with on each cycle. According to Tech Xplore, the zinc battery is efficient and safer than a lithium-ion battery.
  • Zinc-ion batteries: Emerging within the last 10 years, zinc-ion batteries offer many advantages over lithium. These include cheaper material costs, increased safety, and easier recycling options.
  • Sodium-ion batteries: Sodium-ion batteries replace lithium ions as charge carriers with sodium. Sodium is far more abundant than lithium, and you can use salt from the oceans to extract sodium just about anywhere in the world.


[More to come ...]


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