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Electric Vehicle Battery

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

- Overview

Every year, the world runs more and more on batteries. Electric vehicles (EVs) will account for more than 10 percent of global car sales by 2022 and are expected to reach 30 percent by the end of the decade.

Policies around the world are only accelerating this growth: recent climate legislation in the US is pouring billions into battery manufacturing and EV purchase incentives. Several states in the European Union and the United States have passed bans on gasoline-powered cars from 2035.

The transition will require a lot of batteries -- and better, cheaper ones at that.


- 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. 

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.


- 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.




[More to come ...]


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