Solid-state batteries have come to make a difference in the battery industry. Solid-state batteries present a technology that opposes conventional battery technology.
While lithium-ion and lithium-polymer batteries feature liquid electrolytes, a solid-state battery uses solid electrodes and solid electrolytes in its formation. Hence, it is a new, different battery technology from regular lithium-ion and lithium-polymer batteries.
Solid-state batteries are believed to revolutionize the battery industry with many advantages over conventional battery chemistries. Conventional batteries, like lithium batteries, use liquid electrolytes as their conductive materials, but solid-state battery technology changes the game by leveraging solid lithium or sodium-based glass. This ultimately results in enhanced energy density and overall safety of solid-state batteries.
Although they have lower power density, due to the solid electrodes and electrolytes found in solid-state batteries, the batteries have become popular for a higher density. This results in a high power-to-weight ratio, which enhances endurance and makes the new batteries one of the best options for electric vehicles.
Solid-state batteries are coming into the battery world at a time when battery scientists believe that lithium batteries are approaching their limit with limited possibility for improvement. Since solid-state battery technology is just emerging, it has witnessed recognition by battery enthusiasts and a lot of work is underway to make improvements in battery chemistry.
Hence, solid-state batteries are expected to make waves in the battery industry.
Principle of Solid-State Batteries
The principle of solid-state batteries is almost similar to that of the old conventional battery technology, with a few differences, especially with the state of electrodes and electrolytes used.
Traditional lithium batteries have positive and negative poles and a liquid electrolyte in the middle. The charging and discharging process is based on the lithium ions moving back and forth from the battery’s positive and negative poles.
A lithium battery completes a charging and discharging cycle when the lithium ions completely move from the positive pole to the negative pole and back to the positive pole. This is the same principle that solid-state batteries follow.
The only significant difference is that a solid-state battery uses a solid electrolyte. The electrolyte’s solid state allows more charged ions to gather at one end to conduct a larger current, a potential trigger for increased battery capacity.
Hence, a solid-state battery can achieve the same amount of electricity and level of performance as a “liquid state battery” but with a smaller size. The solid-state electrolyte and structure in solid-state batteries also make sealing easier. This eliminates the need for adding extra cooling pipes or electrolyte control, ultimately reducing costs and weight.
Advantages of Solid-State Batteries
The emergence of solid-state batteries is a blessing to the battery industry, thanks to an impressive list of benefits. Here are the key pros of solid-state batteries:
High Energy Density
One significant advantage of a solid-state battery over a traditional lithium battery is the promise of higher energy density.
The solid electrolyte used in a solid-state battery means that other requirements of the battery technology must also change. One of them is the anode used. Instead of using lithium-embedded graphite in the anode, solid-state batteries feature metal lithium, which reduces the amount of material present in the battery. This significantly presents an increased energy density.
Smaller Battery Volume
Traditional lithium-ion batteries require diaphragms and electrolytes in their formation, which increases the batteries’ volume by 40% and the mass by 25%.
Solid-state batteries offer lower volume and mass by using solid-state electrolytes. The solid electrolytes used in solid-state batteries eliminate the use of diaphragms and liquid electrolytes that space the positive and negative electrodes.
With solid-state electrolytes composed mainly of organic and inorganic ceramic materials, a solid-state battery has a smaller space between the positive and negative electrodes in only a matter of tens of micrometers.
High Flexibility
Due to the small amount of materials used, improved flexibility is possible in solid-state batteries. Although ceramic materials can be brittle, they can be flexible when used in small amounts, such that the thickness is only in millimeters.
Another factor contributing to solid-state batteries’ flexibility is their lightweight nature. When appropriate packaging materials are used, the batteries can undergo thousands of bending cycles without compromising performance.
Enhanced Safety
A few safety challenges have been associated with traditional lithium batteries over the period of their reign.
One common danger with lithium batteries is the high risk of lithium dendrite formation when the batteries are subjected to high current operation, a potential cause of diaphragm piercing, short-circuiting, and, above all, damage.
Also, the use of liquid materials in liquid-state batteries poses the threats of oxidative decomposition, combustion, and gas production, which can damage the battery and cause environmental pollution.
Adopting solid-state batteries helps resolve these issues and enhances safety with battery usage.
Ultra-Fast Charging
The capacity to charge faster than their lithium-ion counterparts is one selling point of solid-state batteries. Although more research work is needed to establish the claim, the latest studies showed that solid-state batteries can charge up to six times faster than the traditional lithium-ion battery technology.
However, other studies also claimed that while solid-state batteries charge faster, the feat comes at the detriment of other factors that can reduce the overall performance of the battery.
Regardless, it is certain that liquid-state batteries suffer at high temperatures and experience low performance. Solid-state batteries, on the other hand, experience improved performance at high temperatures and use it to their advantage during fast charging.
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Quicker Production
Some battery enthusiasts believe that producing solid-state batteries is quicker since they require less material than their counterpart lithium-ion batteries. This is linked to solid-state batteries requiring less material in their formation.
However, the inability of solid-state batteries to be mass-produced counters this claim. It is worth noting that the production stages of solid-state batteries require a lot of time. The cells are assembled empty with a hole to fill the electrolyte later on. There is a need to wait for the electrolyte to be absorbed before being refilled to achieve the right level.
Hence, it makes sense to wait until the battery technology reaches a mass production stage to ascertain if it is quicker to produce.
Disadvantages of Solid-State Batteries
Although solid-state batteries offer a couple of advantages over traditional lithium battery technology, they also come with a few challenges.
Low Production Level
Solid-state battery technology is still in the infant stage and still striving to reach the mass production level. Presently, the battery suffers low production efficiency.
High Cost of Production
Since the battery is only produced in smaller numbers, the cost of production can be high. Currently, solid-state batteries are more expensive than traditional lithium-ion batteries, but the cost is expected to drop when mass production is finally achieved.
Lack of Sufficient Development
Although development is still ongoing to further the improvement of solid-state batteries and make them suitable for more applications, the battery technology still lacks suitability in comprehensive applications.
While the new battery technology is already adopted in small applications, it still lacks the performance to meet the needs for large-scale energy storage for comprehensive use. It is believed that it will take a while for solid-state batteries to achieve commercial application.
Overall, battery enthusiasts and scientists predict 3-5 years for solid-state batteries to reach mass production state, while more research and time are crucial to achieve commercialization.
Stability Problems
Critics of solid-state batteries have also pointed out an instability problem with the new battery technology. During the charging and discharging processes, the thickness of the lithium-metal anode expands and contracts, giving a sense of breathing in the battery. With this challenge, a solid-state battery is vulnerable to deteriorating.
The only solution to this challenge is to keep the external structure fixed and the internal parts compressed so they don’t detach. Unfortunately, the internal parts still need to “breathe.” This is why plates with strings are introduced to keep everything compressed.
However, this comes at the detriment of mass production and costs. Repeating this strategy for every battery is costly and heightens the prices of solid-state batteries.
The Separator requires High Temperatures to Perform
Since ions move more freely in liquid-state materials than in solid materials, solid-state batteries require a special composition for the ceramic separator to allow ions to move more freely in.
Although high-performance separators have been engineered to allow free ion movements, ions can only move at high temperatures since solid electrodes only conduct at high temperatures, usually above 50 degrees. When the battery is not hot, the performance is extremely low, and it tends toward zero.
This is one major reason why solid-state batteries are not yet adopted in vehicles, as it is almost impossible to keep the battery hot while used in cars. Further research will, therefore, focus on ensuring that the batteries work and perform well at low temperatures for suitability in the automotive and other sectors.
Shorter Lifespan
The lifecycles of solid-state batteries are significantly lower than what is achieved with liquid-state batteries like lithium-ion chemistry, which can offer more than 4,000 charge cycles. The challenge is linked to the difficulty of the cell’s layers in maintaining constant contact. When the layers lose contact continuously, loss of capacity and performance is inevitable.
Possible Areas of Applications of Solid-State Batteries
Although solid-state batteries need further research work and development, the arrival of the new battery technology is still a blessing to a wide range of sectors, and it has already been adopted in small applications. When solid-state batteries finally gain ground, they will become a force to reckon with, especially in sectors where energy density is a limitation.
The new battery chemistry is believed to make waves in the automotive industry, not only because of its higher energy density but also because it can also contribute to increased range in vehicles.
The electric vehicle sector is particularly eyeing solid-state battery technology with keen interest. This is due to the extensive range requirement of the sector, where traditional battery chemistries seem to have limits.
The industrial machinery sector will also benefit from the low volume that solid-state batteries have to offer. The ability to hold more energy in smaller packages will make solid-state batteries a competitor in the industrial machinery sector.
Overall, solid-state batteries are a pathway to further development in sectors where high energy density is a necessity.
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When Are Solid-State Batteries Expected in The Electric Vehicle Market?
Again, solid-state batteries are already in use in small applications like consumer batteries and small vehicles, but they have not been fully adopted into the automotive industry, and more time is required.
In applications where they are already used, they work perfectly even under intensive use, where continuous use is a necessity. Although they are reported to be hot during extensive periods of use, not so many problems were recorded.
Regardless, solid-state batteries have been featured in a couple of electric vehicle models. For example, the recently launched 50 E70, a product of the Chinese Dongfeng Motor Corporation, features semi-solid-state batteries. Interestingly, the car has shown excellent results in tests related to battery performance.
Although mass production is not certain for now, the introduction of solid-state batteries in their products has shifted the eyes of the automotive world to the Chinese car brand, and more is expected from them. However, critics believe the brand only adopted the technology in their product to be the first brand to debut it in the industry, while some believe the adoption is a marketing strategy to associate their name with the new battery technology.
Regardless, it is difficult to give a particular time frame to expect full adoption of solid-state batteries in electric vehicles since the batteries are still in an experimental stage for automotive use, and a couple of challenges, such as mass production, need to be resolved first.
The only certainty with solid-state batteries in the electric vehicle sector is that technology is paving its way into the sector.
Additionally, other car brands are also looking into the possibility of powering their products with the new batteries. Giant car manufacturers like Volkswagen, Mercedes, and Toyota have expressed interest in doing further research and developing the battery chemistry with readiness to invest huge resources.
These brands will be the first to come out with the first definitive technology, which is expected by 2026.
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