ELECTRIC CAR BATTERIES

Everything you need to know about electric car batteries

#R&D #environmental sustainability #transport

The transition to sustainable mobility and transport electrification are crucial to halting climate change and saving the planet. In the medium term, electric vehicles will replace those with combustion engines, a change that requires research and development of more durable, efficient electric batteries — the core of these vehicles — which must also be kinder to the environment.

A International Energy Agency (IEA) report published in 2018, reveals that transport carbon footprint accounts around 30 % of global greenhouse emissions (GGE). Increasingly stringent transport emissions regulations are being enacted around the world. The European Union (EU) has committed to reducing greenhouse gases by 60 % with respect to 1990 levels by 2050, and the transition toward sustainable mobility and transport electrification is growing in urgency.

THE BOOM AND ADVANTAGES OF THE ELECTRIC CAR

Electric vehicles do not emit polluting gases and are essential to the decarbonised future ahead. This is evident in a gradual increase in sales: 2.2 million electric cars were sold in 2019, 10 % more than in 2018, so that, now one in every 40 cars sold can be plugged in. Of these, 74 % are battery-only electric vehicles (BEV) and the remaining 26 % are plug-in hybrid electric vehicles (PHEV).

Everybody accepts that the future of transport will be electric. However, according to the experts, there are still two unanswered questions, namely: when will sales of electric cars overtake those of combustion cars and what type of batteries will offer the best performance?. According to the Bloomberg New Energy Finance (BNEF) annual report on electric vehicles, sales are expected to keep growing during next decade. The cost of purchasing an electric vehicle is also becoming more affordable. Indeed, according to Bloomberg, electric cars will be cheaper than the equivalent petrol versions by 2022.

One important facet of the electric mobility revolution has been the falling price of lithium-ion batteries, which have dominated the market in recent years. According to BNEF, the price of this type of battery fell from 1,100 dollars per kilowatt hour (kWh) in 2010 to 156 dollars in 2019 (-87 %) and is expected to dip as low as 100 dollars by 2024.

Global growth of the electric vehicle market.#RRSSGlobal growth of the electric vehicle market.

 SEE INFOGRAPHIC: Global growth of the electric vehicle market [PDF]


As well as protecting the environment, electric vehicles have other advantages over combustion vehicles, making them extremely attractive to buyers:

 Fewer breakdowns

Without a traditional engine, gear box or clutch, faults of this type are massively reduced.

 Easy maintenance

With simpler mechanics than combustion vehicles, maintenance is simpler.

 Lower consumption

When charged in a garage overnight, it costs between fifty cents and one euro to travel 100 kilometres (Km), far more economical than a traditional vehicle.

 Fewer restrictions

Pollution has led governments to impose stringent conditions on vehicles in city centres. These do not apply to electric vehicles, which can drive about freely.

 Tax benefits

In many countries, electric cars are given preferential treatment over vehicles with combustion engines, such as no registration charge, no road tax, etc.

WHAT IS AN ELECTRIC CAR BATTERY AND HOW DOES IT WORK?

An electric car battery is an energy accumulator that stores electricity for transmission to an alternating or continuous current engine. However, its importance is far greater than this. The battery is what makes these vehicles sustainable, what releases it from its dependence on fossil fuels. Batteries are at the heart of buyers' concerns: the car's range — the distance that a vehicle can travel before needing a charge —, its charging time and its price.

The battery world has experienced an unprecedented revolution in the last decade. As a result, the average range of electric cars has increased considerably, eliminating what is known as range anxiety — buyers' fear of finding themselves stuck on the roadside due to limited range — which had been holding back sales. However, range is not the only area of batteries where progress has been made: charging times have also been improved — with rapid charging as fast as ten minutes — improving their efficiency and their life cycle.

CHARACTERISTICS OF ELECTRIC CAR BATTERIES

Electric vehicle batteries are special in several ways. The main ones include:

 Density

The amount of energy that a battery is able to store in relation to its weight. The greater the density, the greater the storage capacity and the longer the vehicle range. It is expressed in Wh/kg (watt-hours per kilogram).

 Voltage

The power that the battery can supply per kilogram of weight of the battery, which is therefore expressed as W/kg (Watts per kg). The greater the power, the greater the performance of the vehicle.

 Efficiency

The performance of the battery, i.e. the percentage of energy it is capable of delivering in relation to the energy introduced into the charging process.

 Life Cycle

The number of times that a battery can be charged and drained before needing replacement, since they lose capacity. The more cycles the battery has, the longer it will last.

 Charging speed

Charging times. There are three types of charge, with times that vary depending on the model of the car: rapid (10-40 minutes), fast (1.5-3 hours), and slow (5-8).

HOW TO EXTEND THE LIFE CYCLE OF AN ELECTRIC CAR BATTERY

According to the study conducted by Geotab in 2019, electric cars lose an average of 2.3 % of their range every year. These are the main steps for taking good care of an electric car battery:

  • Avoid fully charging and draining the battery, in the same way as mobile phones and laptop computers.
  • Charge your car using smart chargers and, where possible, with a slow charger — rapid charging shortens the battery life by 1 % if used frequently —.
  • Electric cars are best in urban environments. Accelerate gently and do not park in the sun to avoid triggering the thermal management system.
  • The braking system helps to charge the battery, so the more you use the brakes the longer range it will have.

THE LATEST IN BATTERIES FOR ELECTRIC CARS

Batteries are the subject of constant innovation. Recently, Swiss startup Innolith AG announced that it had developed a denser battery without increasing the weight or size, capable of storing more energy and increasing the range to up to 1,000 km. The secret: lithium batteries with non-flammable electrolytes. A group of researchers at the University of Melbourne has announced the development of a lithium and sulphur battery with the same range.

Solid-state batteries based on electrolytes may also be positioned at the forefront of the sector because they are cheaper, lighter and smaller, increase energy density and do not need safety systems to prevent heating. Other sources point to batteries with silicon anodes can store up to ten times more energy than a lithium battery, and graphene-based anode materials can increase battery capacity and drastically reduce charging times, with an energy density and useful life twice that of lithium.