The transport industry is currently undergoing a revolution with EVs or electric vehicles on the roads. EVs require batteries, and many EV manufacturers are now manufacturing their own batteries, targeting low-cost batteries with the most range and the fastest charging speed. While many industries are still using lithium-ion batteries, others are moving towards solid-state batteries. Compared to a few years ago, major breakthroughs are finally bringing solid-state batteries closer to mass production.
Although solid-state batteries have been in existence for some time now, and scientists have been researching them, they have been commercially available only in the last decade or so. Specific advantages of solid-state batteries include lower costs, superior energy density, and faster charging times.
Many companies have been researching solid-state battery technology for years. For instance, Toyota claims to be on the verge of producing solid-state batteries commercially for EVs, and they hold more than 1,000 patents.
Conventionally, a lithium-ion battery has an anode and a cathode, with a polymer separator keeping them apart. A liquid electrolyte floods the entire cell and is the medium through which lithium ions can travel while the battery is charging/discharging.
In a solid lithium-ion battery, a solid electrolyte layer separates the anode and the cathode, allowing lithium ions to travel through it. The anode is of pure lithium, which gives it a higher energy density than that of regular batteries. Theoretically, the energy density from solid lithium-ion batteries is roughly about 6300 watts per hour. Compared to the energy density of gasoline, a solid lithium-ion battery offers an energy density of about 9500 watts per liter.
The major advantage of solid-state batteries is their smaller size and weight. Additionally, they pose no fire hazards. As these batteries are very safe, they do not require as many safeguards to secure them. Their smaller size allows packing them to higher power capacity, and they do not release toxins. Solid-state batteries run 80 percent cooler than regular batteries.
With all the above advantages, using solid-state batteries in electric vehicles offer them greater range, safer operation, faster charging, higher voltages, and longer cycle life. However, solid-state batteries must overcome some disadvantages still.
The first of these obstacles is the dendrite formation. Lithium is a highly corrosive metal, requiring the use of chemically inert solid electrolytes. Over time, dendrite growth increases to the extent of destroying the battery. During charging, these batteries usually grow spike-like structures that can develop and begin to puncture the dividers, causing short-circuits in the battery. Manufacturers are using ceramic separators to overcome the dendrite menace.
Solid-state batteries currently do not perform well at low temperatures. This affects its long-term durability.
So far, the biggest detriment to solid-state batteries has been their exorbitant cost. However, present indications from manufacturers like Toyota suggest they have surmounted the price barrier.
Therefore, at present, the only problem still remaining for solid-state battery commercialization is their low-temperature performance. To be a viable alternative, solid-state batteries must perform in all kinds of variable environments and climates. However, manufacturers are offering assurances that they have overcome this hurdle also. Recharging stations need to be able to handle the faster-charging currents as compared to that of regular lithium-ion batteries.