• Solid-state batteries offer several advantages over traditional lithium-ion batteries, including no thermal management system requirement, better performance in extreme temperatures, increased range, speedier charges, more lifecycles, and enhanced safety.
• Solid-state batteries have a higher energy density, which means they can provide a longer range and longer life compared to lithium-ion batteries. Solid-state batteries can go through 8,000 to 10,000 charge cycles, while lithium-ion batteries are estimated to have 1,500 to 2,000 charge cycles.
• Solid-state batteries are intrinsically safer than lithium-ion batteries, with a higher degree of impact resistance and a lower risk of catching fire. However, solid-state battery technology is still in development and not yet commercially available on a large scale.

The explosion of the Electric Vehicle (EV) market has spawned the need for a vast expansion of the battery industry. The electric car battery is still a newer concept for many car buyers of today, and a component of the vehicle that is not going unquestioned. Whether it is cost, longevity, replacement viability, range, or safety – drivers want to understand not only the EVs themselves, but also the batteries that will power their automotive purchase.

This comparison of the solid-state and lithium-ion battery will shed light on what you need to know regarding the differences between these two electric car battery types. It is important to point out that several automakers are working on developing solid-state batteries, with Toyota being one of the most prominent researchers in the field, along with Nissan, and others. But even so, best-case predictions expect this tech to be available in the second half of the decade.

By researching information from J.D. Power, ScienceDirect, and an interview with Solid Energies’ Kevin Zanjani, who holds a trio of degrees – a BSEE, MSECE, and MBA, we discuss below the difference between lithium-ion and solid-state batteries.

EV Battery Basics

Solid-State And Lithium-ion Batteries

To understand the differences between a traditional lithium-ion and a solid-state battery, we took a layperson's look at the basics. The big difference in electric car batteries is that a traditional lithium-ion battery contains a liquid electrolyte to conduct lithium ions between the cathode and anode. Whereas in a solid-state battery, as the name suggests, a solid electrolyte is used instead of the liquid, which provides an overall lighter weight and a higher energy density.

How do liquids and solids and energy density translate into consumer benefits and market drivers of the EV industry? Well, there are a few primary reasons for the adoption of the new solid-state technology over traditional lithium, and those are:

• No thermal management system requirement
• Performance in extreme temperatures
• Increased range
• Speedier charges
• More lifecycles
• Enhanced safety

EV Batteries: Thermal Management Systems And Temperature Swings

Extreme Temperatures, High or Low, Are The Achilles' Heel Of Lithium-ion Batteries

At lower and higher temperatures, a solid-state battery can perform more efficiently and longer than a traditional lithium-ion battery. According to Kevin Zanjani:

Research has shown a solid-state battery will function well, down to about minus 40 degrees Celsius. Right now, the current lithium-ion battery doesn’t work sufficiently well at low temperatures and the amount of usable range is much, much less at freezing temperatures. Once the thermal management system is removed, there are tremendous cost savings. It is a conservative speculation of 20 to 30 percent savings, but possibly 50 percent.

Current lithium batteries require a thermal management system to heat the battery when it’s cold and to cool the battery when it is hot. A solid-state battery will work at more extreme temperatures without the added equipment and cost of a thermal management system.

Solid-State Batteries: Longer Life, Less Charging

A Breakthrough for Electric Vehicles

As drivers, the biggest draw to EV ownership is the thought of eliminating our regular gas station fill-ups, which are currently topping $6 a gallon for Californians. But with that benefit comes the trade-off of needing to charge our cars, like we do our phones, and everyone knows how inconvenient a low battery bar is on a cellphone. So, what is the real cost we will pay in relation to real-world travel time vs. charge time to “refuel”?

Car manufacturers know how important that range (how far an automobile will travel on a charge) is to the consumer, and they want EVs to have a range that is equivalent to a gasoline-powered vehicle. Something like 350 miles on a charge is a target, because that is what people are used to.

Again, The Advantage Goes To Solid-State Over Lithium-ion In The Range Category

Since solid-state has more energy density, this type of battery also has a longer range, even under heavy load, such as when towing or working in extreme weather. But solid-state is not just about a longer range, it is also about longer life. Solid-state technology will offer more charging cycles than lithium-ion batteries. The predicted assumption from Zanjani is that a solid-state battery EV will be able to go through somewhere between 8,000 to 10,000 charge cycles when done properly. This is quite an improved benchmark over the lithium-ion's 1,500 to 2,000 EV charge cycles estimated by Midtronics.

EV Safety: Battery-Related Fires

As Safe as They Are, Lithium-Ion Battery Fires Are Hard to Extinguish. Concerns over lithium-ion batteries blew up (no pun intended) when videos of exploding cellphones, laptops, hoverboards, and other toys were witnessed on YouTube and highlighted in the evening news.

Carpets were scorched, people were harmed, and families even displaced when houses were left burned and smoldering with lithium batteries named as the culprit. Fires from lithium-ion batteries are blamed on faulty manufacturing, overcharging, overheating or severe impacts. And 'severe' can even translate into simply dropping the battery, while crushing and piercing are also included.

Solid-state Batteries Are Believed To Be Safer

A 2018 report from the Consumer Product Safety Commission identified more than 25,000 incidents of overheating or fire hazards in more than 400 types of products over a five-year period. Taken as a whole, this seems like an infrequent number of occurrences. However, the situation does underline the fact that a battery’s stability should be considered for the EV market, especially when traveling at driving speed and the potential for collisions. Solid-state technology does just that. The solid-state battery is intrinsically safer than the traditional lithium-ion battery. It has a higher degree of impact resistance without catching fire.

Next-Generation of EV Batteries

Solid-State Battery Technology Is Still Under Development

So, with all the advantages that solid-state batteries have over lithium-ion, why aren’t they in mass production for every EV manufacturer? Well, at least for the time being, lithium-ion and solid-state batteries are miles apart in commercial use. Lithium-Ion batteries have been in existence for years. However, the technology for solid-state batteries is still in development.

According to Zanjani, working solid-state prototypes are only being built by a few companies, and right now, the current state-of-the-art technology that can be purchased is still Lithium-Ion. Lithium-ion is also an umbrella term for other chemistries being studied, such as Lithium ferrous Phosphate (LFP), Lithium Nickle Manganese Cobalt Oxide (NMC), and Lithium Nickel Cobalt Aluminum (NCA).

A Solid-State Battery Standard Is Needed

Although solid states are not in a place for mass commercialization, it is believed that they are the next-gen technology of batteries. One of the challenges is to bring the technology to scale. With each EV battery being built differently, to several different EV platforms, each proprietary to its manufacturer, solid-state will have a hard time coming to scale. If the industry adopts a standard in this regard, then the technology will come sooner.

A scaling EV battery market is what the consumer will need to see a drop in battery production pricing and thereby, theoretically, a reduction in EV cost. That thought does not consider the now commonplace supply chain and labor force issues or dealer mark-ups.

The Solid-State Battery Race is On

Research And Development in The Field Indicates Solid-State Batteries Are The Future

Under common ownership, Bioenno Power and Solid Energies have a working solid-state prototype. Something that's been in development for about six years. The EV market is prompting the car manufacturers and the OEM to pressure the battery manufacturers into production, and the race is on, with a lot of activity in the area.

Battery companies are working together with auto manufacturers to establish a final product. Currently, however, this endeavor is capital intensive, requiring funding not only for research but also for the required production infrastructure.

Some automakers have become interested in joint ventures with existing battery manufacturers, others want to go the route of an in-house build. It could be better to work with companies that have already spent a considerable amount of effort and resources on solid-state battery technology because they are closer to a production-ready solution.

So, for now, what we know is there is significant value expected for the consumer in the evolution from lithium to solid-state EV battery use. Once production ramps up, we will know more and only time will tell if the benefit of cost reduction will trickle down to the end-user – us, the car buyers.