What is a Solid-state Battery? A Complete Explanation

What is a Solid-state Battery? A Complete Explanation

Let’s have a brief discussion about solid-state batteries, which are definitely the wave of the future.

“Solid state” batteries are one area being explored. This replacement for the lithium-ion batteries currently in use promises to extend the driving range of vehicles, shorten charging times, and eliminate the possibility of battery fires. Many believe that this lithium-ion substitute will almost double vehicle range and cut down on charging time, drastically altering how people view and perform electric vehicles.

But when we talk about a solid state, a variety of different factors come into play, with a series of great advantages but also many limits that are still being studied and, to date, are delaying its entry into the market. Let’s clear things up.

What is a Solid State Battery?

In the same way as any other battery, solid-state batteries function. They absorb energy, store it, and then release it to power gadgets like Walkmans, watches, and now car motors. The internal components make a difference.

Lithium-ion batteries, used in EVs today, have a liquid electrolyte solution sandwiched in between their cathodes and anodes (see the middle gap in the image above). Alternatively, solid-state batteries use solid electrolytes.

Solid-state batteries can store anywhere from two to ten times as much energy as lithium-ion batteries due to their increased density.

What is a Solid-state Battery? A Complete Explanation

How Do Solid State Batteries Work?

If we’re being honest, it works pretty much the same as a standard battery. The flow of ions triggers a chemical reaction between the battery’s materials called ‘Redox’ where, when discharging power, oxidation occurs at the anode to create compounds with free electrons, which deliver electric energy, and reduction at the cathode which sees compounds gain electrons and thus store power. The procedure is reversed when a battery is charged.

Similar to lithium-ion batteries, when solid-state batteries deliver power, or discharge, positively charged ions move from the negative electrode (anode) to the positive electrode (cathode) through the electrolyte. This leads to a build-up of positive charge in the cathode which attracts electrons from the anode. However, because the electrons can’t move through the electrolyte, they must move across a circuit to power whatever it is connected to, like an electric motor.

The opposite occurs during charging, with ions flowing to the anode building up a charge that causes electrons to be drawn to it across a circuit from the cathode. The battery is said to be fully charged when no more ions can flow to the negative electrode.

Although they have been around for a while, solid-state batteries are currently only used in very small electronic devices like pacemakers and RFID tags, and they are not rechargeable. As a result, efforts are being made to enable their recharge and ability to power bigger devices.

Do Solid State Batteries Increase Range?

EVs should be able to travel the same distance between fill-ups as gas-powered cars with the help of a solid-state battery. As an illustration, consider a 15-gallon gas tank with a 30 mpg rating. That car can go 450 miles before filling up.

Most EVs today have ranges of 200 to 300 miles, although the 2024 GMC Sierra Denali pickup truck will have a 400-mile range, and the super-luxe Lucid, already on the road today, boasts a 520-mile range.

Multiplying those ranges by around 50% (or as much as 80%, CarBuzz reports), solid-state batteries are ready to play ball on road trips. 450 miles have been added to an EV’s original 300-mile range. Additionally, solid-state batteries charge more quickly than lithium-ion batteries while causing less damage to the battery itself.

What is a Solid-state Battery? A Complete Explanation

What Are the Current Strengths of Solid-state Battery Technology

On paper, solid-state batteries promise many improvements over the current batteries on sale; in fact, solid electrolytes seem to offer greater energy density, longer life, and more excellent safety, all in a smaller size.

But it’s important to keep in mind that this technology is still in the development stage, and lithium-ion batteries continue to offer the best performance among commercially available technologies thanks to their availability in a wide range of chemistries, each of which is used for a different purpose.

However, let’s have a look at the advantages offered by solid-state batteries:

The Key Factor of Safety

Solid-state batteries do not have a liquid electrolyte, which in lithium-ion batteries is one of the most challenging components in terms of safety because it is volatile and therefore more flammable.

Furthermore, this is replaced by a thicker separator layer formed of a material that is mechanically more resistant to high temperatures (because it has a ceramic composition with various additives); this makes the separation between the anode and cathode more reliable, so much so that it prevents short circuits, even in the event of misuse or deterioration, and therefore the intrinsic safety of the cells increases.

Another advantage in terms of safety is the greater resistance to dendrites or the sharp, uneven build-up of lithium that forms during movement from the cathode to the anode. Lithium actually moves unevenly and has the propensity to cluster and form points that, like accurate pins, enlarge and, in some rare circumstances, have the ability to pierce the separator.

However, solid separators are more resistant to dendrite piercing because of their thickness, which helps to prevent potential short circuits and the gradual degeneration of the cell.

What is a Solid-state Battery? A Complete Explanation

Record Energy Density

The greater intrinsic safety helps bring another major improvement: the use of a pure metal anode encourages a huge increase in energy density. This is largely due to the removal of the graphite anode, which in lithium-ion batteries serves as the ion’s container during ion migration. During the transfer in a solid-state battery, a big, heavy compound part that doesn’t actively contribute to energy generation is removed, leaving only the ions.

According to the latest studies, solid-state batteries have an energy density 2-2.5 times higher than current lithium-ion technology and this huge advantage would result in a lighter and smaller battery.

This is undoubtedly a breakthrough for electric mobility, which would gain from a longer range and a lighter weight, but keep in mind that we won’t know for sure until this technology is formally ready.

Ultra-fast Charging Times

The latest studies have shown that solid-state batteries are able to charge up to 6 times faster than the current technologies on sale. But this figure is also still uncertain and will depend on how this new technology is developed. There are already solid-state battery prototypes that charge incredibly quickly but at the expense of other essential elements for achieving good performance.

We will need to weigh up this advantage with other essential characteristics that these batteries should have, only then can we assess the best alternative, including cost.

To date, what is certain is that liquid electrolytes tend to suffer at high temperatures, while solid electrolytes, on the contrary, become more high-performance at high temperatures and this would support their performance during fast charging, an operating phase that typically produces much higher temperatures.

Quicker Production

What is a Solid-state Battery? A Complete Explanation

Some people argue that a solid-state electrolyte, as it is not liquid, can allow a quicker, easier production process, which uses less material and energy; but this theory, while understandable, also cannot yet be proven and only will be when this technology is truly mass produced.

However, we can certainly say that at the moment the filling of the cell with the electrolyte is a process that requires plenty of time: the cell must be assembled empty and it must have a hole so the electrolyte can be filled up later on, you will then have to wait for the electrolyte to be completely absorbed and, afterward, you will need to refill it to bring it to the right level and seal it.

Therefore, it is unquestionably a crucial stage in the production process, and solid-state technology has the potential to make real advancements. However, before drawing any firm conclusions, we must wait until these cells are actually produced.

What Will be the Main Drawbacks of the Application of Solid State Batteries?

As we’ve seen, solid-state batteries have the potential to bring about a revolution in the automotive industry’s electrification sector by offering significant advantages that will boost vehicle performance and efficiency. But even though the market entry of solid-state technology already appeared to be just around the corner a few years ago, it has yet to materialize. How come?

Just as there are many advantages, there are also certain limits due to how young this technology is, as it is still not ready and constantly evolving. This is why we can call these limits real challenges to be addressed and major new goals to be achieved. Let’s find out together.

Stability Problems

The solid-state cell appears to be breathing while being charged and discharged. Like all unstable elements, the lithium-metal anode thickens during charging and thins out during discharging, which will eventually lead to degradation.
The main problem comes from the difficulty of keeping the solid-state cells fixed and compressed at the same time.

A cell should be compressed so that the internal layers do not detach, but it is not enough to fasten it to a containing structure, because this will constantly need to “breathe”. You, therefore, need to create a complex mechanical design: in “tabletop” solid-state battery prototypes, plates are installed with springs that keep everything compressed, but this is a complex and expensive system that cannot be mass-produced.

What is a Solid-state Battery? A Complete Explanation

The Separator Only Performs at a High Temperature

Ions are made up of matter, or atoms, so it makes sense that they would move more readily in a liquid than in a solid (such as a ceramic separator), requiring a unique composition to enable ion movement.

There are already high-performance separators in this sense, but only at high temperatures, because solid electrodes only become good conductors at temperatures above 50 degrees. Due to the fact that we cannot assume the battery is always hot, solid-state technology is still hardly utilized in actual automobiles. When the solid-state battery is not hot, its performance currently falls considerably. To make sure the solid electrolyte functions well at progressively lower temperatures, work will need to be done.

Life cycles Are Still Short

The life cyclesof solid-state batteries currently being tested are still shorter than other lithium-ion technologies, such as LFP chemistry, which easily exceeds 4,000 charge cycles.

The main problem is the fact that it is tough to get good contact between all the cell layers. The cell becomes less functional and has less capacity when the layers start to lose contact.

High Cost

The cost of a solid-state battery is currently very high because we are talking about an extremely innovative technology; so the costs of both the materials and the production processes need to be higher than for mass-produced batteries. It is not yet clear what the final cost of this technology could be, but we can certainly assume that, if major car manufacturers are investing in this direction, they have enough evidence to believe that the cost can also be adapted to mass production.

Conclusion: What is a Solid State Battery?

It’s unlikely that lithium-ion batteries will be replaced by solid-state batteries anytime soon given the advancements made in them, the millage that can be obtained from them, and the way that they are already being mass-produced.

Solid-state batteries are currently perceived as having a drawback due to their complexity in mass production and manufacturing. But that’s something the manufacturers will figure out sooner rather than later, just like other automotive technologies that have entered the mass market.


Is Solid-state Battery Better?

A solid-state battery can store more energy with fewer materials and can decrease the carbon footprint of an EV battery by 24%. Additionally, using technology and materials from sustainably managed supply chains could cut the carbon footprint of EV batteries by as much as 39%.

How Long Do Solid-state Batteries Last?

Solid-state batteries could be recharged up to seven times more, giving them a potential lifespan of ten years as opposed to a couple of years a lithium-ion battery is expected to effectively last.

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