EV Basics – EV Batteries

EV batteries

The lithium ion-battery is the most important component of an electric vehicle, as it is the energy source. The battery size is demonstrative of the vehicle’s driving range and charging capabilities. Battery size will also affect the cost of the vehicle.

It is important to consider how to manage your electric vehicle battery, as its condition can impact residual values and vehicle efficiency.

An electric vehicle battery

The most common type of electric vehicle battery is made of lithium-ion. This is due to their specific energy (Wh/kg), cycle life and high efficiency. The battery is made up of two electrodes in an electrolyte.

The electrolyte is where the exchange of ions takes place to produce electricity. The lithium ions act as the charge carrier, allowing for the simultaneous exchange of positive and negative ions in the electrolyte. There are many options for the materials of the electrodes and electrolytes, hence there are different possible battery chemistries, each with their own advantages and disadvantages.

These include:

Cobalt Oxide (LCO)
Lithium Manganese Oxide (LMO)
Lithium Iron Phosphate (LFP)
Lithium Nickel Manganese Cobalt Oxide (NMC)
Lithium Nickel Cobalt Aluminium Oxide (NCA)
Lithium Titanate (LTO). [1]

Comparisons of different types of Li-ion batteries used in EVs from the following perspectives:

specific energy (capacity)
specific power, safety
performance, lifespan and cost.

Source: Miao Y. et. al, Energies, 2019

Battery life

Electric Vehicle (EV) batteries do not need to be replaced as frequently as a battery in an ICEV. Car manufacturers offer battery warranty to provide comfort for consumers, though it is not intended to be demonstrative of a battery’s life.

A BEV may need a battery replacement after 10-20 years, just like parts in an ICEV will need to be replaced over its lifetime. In an ICEV there are more moving parts, so there are more things to be replaced.

Battery charging

Electric vehicles now include Battery Management Systems (BMS) that limit charging capacity to prolong battery life. They control the temperature of the battery to reduce degradation and capacity loss. [2]

As electric vehicle batteries are lithium-ion it means that certain conditions degrade the battery over time. It is important to charge the battery according to the guidelines to get the most out of the technology.

Australian driving habits indicate an average drive distance of less than 50km per day, [3] so most drivers wouldn’t have to recharge daily given that the average BEV range for 2018/2019 Battery Electric Vehicles is 379km at 100% charge. [4]

There are different ways to charge an EV, all with different capacities and time frames to suit the situation. There are currently four levels of chargers. For more information, refer to the All about chargers article.

Battery conditions

Heat can affect battery life, so automakers are continuously innovating and investing in thermal management systems which protect the battery in harsh conditions.

Battery Thermal Management Systems (BTMS) form part of the battery cells to protect EV batteries by warming them up or cooling them down as required. A BTMS consists of systems that may be either active (external or internal sources of heating and/or cooling) or passive (natural convection). [5]

Climate has not shown to be a barrier to uptake in warm or cold regions. California, which has a similar climate to the highly populated areas of Australia, has reached EV market penetration of 9% EV uptake in June 2021. [6] India, with a comparative temperature to the northern regions of Australia, has committed to EV policies to build India ‘as a driver in electric vehicles. [7] Norway, with an average winter temperature of -6.8°C [8] has the highest global EV uptake and a 54.3% market share of BEVs as of December, 2020.

Battery technology: cost and range

Battery prices

Battery technology is constantly evolving, and as battery technology develops, the kWh cost of the battery drops. The price of a lithium battery has dropped significantly since 2010. In China the minimum reported price for batteries in e-buses is below $100/kWh. [9] On average, it is expected that the battery cost will reach $100/kWh by 2023.[10]

Source: Union of Concerned Scientists

Technological advancements are increasing Lithium-ion battery capacity, and innovation in the chemical make-up of lithium-ion batteries is driving the price of vehicles and end-of-EV-life replacement down. New developments include NCM 811 cells (available as early as 2019), [11] Lithium-sulfur, and lithium-solid state (2020-2030). [12, 13]

Battery sustainability

Read more about battery recycling and repurposing here.

References

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