A breakthrough in EV battery tech

Source: The post is based on the article “A breakthrough in EV battery tech” published in Business Standard on 21^st April 2023.

Syllabus: GS 3 – Science and Technology

Relevance: About Sodium-ion batteries

News: The demand for Electric Vehicle (EV) is on rise. As per the Economic Survey 2022-23, EV market is projected to grow at a compound annual growth rate of 49 percent between 2022 and 2030, and annual sales are expected to reach 10 million by that time.

This will add pressure on the battery supply chain. Hence, there is a need to diversify the battery market from lithium-ion batteries to more cost-effective batteries like sodium-ion batteries.

How are sodium-ion batteries better than lithium-ion batteries?

The cheapest lithium-ion battery is LFP (lithium-iron-phosphate). However, the rapid growth in the worldwide EV battery demand has caused problems with lithium mining and the prices have also increased.

In such a case, sodium-ion batteries are the alternative. Large quantities of sodium can be extracted from both the earth’s crust and seawater and at a lower cost than lithium.

Moreover, an aluminium current collector can be used at both electrodes, unlike the lithium-ion battery, which requires a more expensive copper current collector at the anode.

Overall, a sodium-ion battery is 20-30 percent cheaper than an LFP battery. Further, the Sodium-ion battery has no over-discharge characteristics, which means it can be allowed to discharge to zero volts.

This reduces the chances of fire hazards during transportation, unlike lithium batteries which must always be stored with a minimum charge.

Sodium-ion batteries have faster charging times and could have a longer lifespan compared to lithium-ion variants.

What progress has been made for sodium-ion batteries and what are the associated challenges?

There are many companies working on sodium-ion technology.

For example, the world’s largest EV battery manufacturer unveiled its first-generation sodium batteries in mid-2021 and announced a commercial launch in 2023.

However, a major challenge in scaling up production is the development of suitable materials and supply chain for both electrodes and the electrolyte.

Another concern is that it is often argued that sodium-ion batteries are heavier than the lithium-ion variants for the same energy delivered due to higher density.

However, the first generation of sodium-ion batteries has reached energy densities up to 160 Wh/kg while the most recent LFP batteries have achieved just over 180 Wh/kg.

How are sodium-ion batteries relevant for India?

A large part of the Indian market in the next decade will comprise smaller sub-10kWh batteries that go into two- and three-wheelers. Due to which, manufacturers have switched to LFP batteries given its low costs.

However, these batteries have higher densities making them heavier.

They can be replaced by sodium-ion batteries as sodium-ion batteries offer a cost-effective option for applications where weight and energy density are less of an issue.

What can be the way ahead?

Sodium-ion batteries present a promising opportunity in developing India’s home-grown battery technology, thereby reducing the dependency on oil imports.

Moreover, the need for accelerated growth of EVs at a lower cost offers the opportunity for India to become a global leader in manufacturing sodium-ion batteries.