Toyota's EV batteries

Pictured: Lithium-ion batteries, commonly used in electric cars. (IMG/ Shutterstock)

Why are solid-state batteries so important?

Solid-state batteries have been hailed as the “holy grail” of electric vehicle (EV) batteries, but what exactly are they all about? 

To answer that, we first need to look at how electric vehicles work. 

Electric vehicles, also known as all-electric vehicles or battery electric vehicles, are powered by an electric motor instead of an internal combustion engine. 

EVs are fitted with a large traction battery pack, which is rechargeable through charging equipment directly connected to a wall electricity outlet (also known as electric vehicle supply equipment, EVSE). 

As EVs run purely on electricity from batteries, it doesn’t emit exhaust, unlike combustion engines that use petroleum or natural gas. 

The refinement, extraction, and use of petroleum require fossil fuels, which are non-renewable resources that pollute the earth with greenhouse gases, the prime cause of climate change. 

As such, EVs are theoretically ideal as a mode of transport that would have a lower impact on the earth, despite the fact that the production of electricity (such as from non-renewable resources) also contributes to climate change. 

Issues with current EV battery tech

Theoretically, EVs may sound like the answer to combating climate change — at least, from a vehicular standpoint. They’ve also been called “green vehicles”, but that isn’t necessarily accurate, especially if the user cannot reliably determine the source of their electricity. 

As pointed out, the use of electricity currently suggests that EVs would most likely also use electricity from non-renewable resources such as coal.

Ideally, all production of electricity should be “green”, in order to power not just vehicles, but the world. However, we are still quite a ways from that.

Power source issue aside, EVs are notorious for several problems, with the most off-putting one being that current battery packs, especially for smaller models, do not contain enough electricity to power the vehicle for long distances due to their small size.

As compared to conventional combustion vehicles, EVs, especially those in the more “affordable” ranges, cannot usually travel as far as the former can. The rule of thumb for EVs is that, the pricier your EV, the longer the driving range.

The driving range of EVs can last anywhere from 95 to 750 kilometers, with the average being around 300 kilometers for most modern models. This can be an issue if one is, say, traveling long-distance between states in a huge country. 

On its own, it may not sound all that serious, but it becomes a huge problem when you add in factors such as the lack of EVSEs, especially a dearth of critical infrastructure such as charging stations, as well as long charging times.

Current EV battery technology is limited, and the length of time needed to recharge EVs can take anywhere between 1.5 to 3 hours, which makes it inefficient, when you compare it to the 30 seconds or so needed to fill up a gas tank.

Advantages of EVs

Although the purchasing costs can be significantly higher than combustion vehicles, EVs generally have lower energy costs.

Moreover, as manufacturing volumes increase and research on solid-state batteries continue to improve, the prices of electric vehicles are most likely to equalize to be on par with conventional vehicles, hence reducing costs and making them more affordable.

EVs also have the benefit of flexible charging where their batteries can be charged in most parking locations, such as residential and public parking spots. Public charging stations are not as common as gas stations in the current state, however, which makes the charging process tougher.

Besides that, EVs are able to reduce emissions significantly compared to conventional vehicles as they solely rely on batteries to operate. Conventional cars utilize gasoline and petroleum, and tailpipe emissions released by them can lead to environmental pollution and carbon monoxide poisoning. 

Solid-state batteries

Due to current issues with EV battery technology, solid-state batteries are a potential game-changer for EVs. They come with the promise of low costs, higher performance, and better safety

Most EV companies use “wet” lithium-ion batteries, which use liquid electrolytes to move energy around. But these batteries can be slow to charge, freeze up in subzero temperatures, and contain flammable material that can be hazardous in the event of a crash.

Solid-state batteries, however, could potentially allow the EV to travel over 300 kilometers and fully recharge in as short as 10 minutes. 

Additionally, they have the potential to minimize the risks of fires compared to conventional lithium-ion batteries and occupy far less physical space.

The science of solid-state batteries

Solid-state batteries, unlike lithium-ion (Li-on) ones which use liquid electrolytes, uses a solid electrolyte instead.

As solids are usually better conductors of electricity, this theoretically means that more energy may be stored in a smaller amount of space, and charging would be much faster.

Furthermore, liquid electrolytes are flammable and volatile, hence increasing the risk of accidents — a disadvantage that solid electrolytes avoid.

The battery’s negative terminal, called its anode, is made from pure lithium metal. This combination would send its energy density through the roof, enable ultra-fast charging, while also eliminating the risk of battery fires. 

As EVs account for about 60% of all Li-on batteries made today, IDTechEx predicts that solid-state batteries will represent a US$6 billion industry by 2030.

What’s hindering the development of solid-state batteries?

Firstly, the initial costs of research and development of solid-state batteries are rather high, making them out of reach for many, and affecting their commercial viability.

Development-wise, it’s still a challenging task to design a solid electrolyte in the battery that is stable, inert (non-reactive) to other materials, and maintains good electrical conductivity.

Solid-state batteries may also cost more to fabricate as the electrolytes may expand and contract while in use, which makes them prone to shattering

One way to speed up the process of finding suitable materials is by using quantum computing — an approach currently utilized by Toyota. Currently, battery manufacturers do have prototypes, but are finding it a challenge to scale production up for commercial viability. 

Furthermore, the EV battery market supply chain is expected to further impede market growth as industry players will take some time to recover from the financial impacts of the pandemic. As if that’s not enough, there is a dearth of qualified talent in the EV battery industry.

Nevertheless, over time, as the world stabilizes and recovers from the dastardly impacts of the pandemic, these costs would even out. With enough investments and interest in progressing the technology, it may even be cheaper than producing Li-on batteries.