Our daily needs more and more batteries of greater capacity, durability and stability. Whether for mobile devices or electric cars , the need for better batteries is evident. Brands like Tesla have achieved authentic feats in the management of lithium-ion batteries, improving the autonomy of their models without changing the batteries. But it’s not enough.
If one day the electric car wants to supplant the thermal motor car as a means of transport, the batteries must offer greater autonomy, greater stability and even safety. And it is something that could be achieved with the so-called solid state batteries.
Toyota , for example, believes that by 2022 it could launch an electric car equipped with solid state batteries. And it is not the only manufacturer that has placed high hopes on this new technology. Until recently Dyson planned to manufacture an electric car , and had its subsidiary Sakti3 developing this technology. Smartphone manufacturers also opt for solid-state batteries, such as Samsung. Although in this case they are more interested in the security they offer since they cannot catch fire as a “classic” lithium-ion battery.
What is a solid state battery?
The solid-state battery is an evolution of the lithium-ion battery and we owe its main development to John B. Goodenough, the father of the lithium-ion battery, from the University of Austin (Texas). And at 94, he continues to lead a development team to make solid state batteries a practical reality. But to understand how a solid-state battery works, we must first remember how a lithium-ion battery works.
A lithium-ion battery is composed of two metal electrodes (or composite material), one being cathode and the other anode, immersed in a conductive liquid (electrolyte). The set is what is called a cell. And the combination of several cells forms the battery. The battery uses as a electrolyte a lithium salt that achieves the necessary ions for the reversible chemical reaction that takes place between the cathode and the anode.
When the battery is charged and a device for power is connected, for example when we start the car, the electrical circuit of the assembly closes. This activates a chemical reaction that causes the circulation of ionized particles from one electrode to another, dragging the production of electrons to the battery terminals, that is, “releasing” the energy. And if a charger is then connected to the battery terminals, a reverse chemical process occurs: particles circulate in the other direction and the battery is recharged.
A solid state battery works on the same principle as a lithium ion, the main difference is in the electrolyte. In the first case it is a liquid and in the second a solid material. In the investigations of the John Goodenough team a crystal electrolyte is used that would facilitate its mass production, but there are other teams working with other types of materials, such as gold nanowires wrapped in manganese immersed in turn in a gel . Toyota, meanwhile, keeps secret what solid it uses.
What advantages does solid state batteries provide?
In theory, the solid state battery would be the panacea for the electric car boom . Toyota refuses to manufacture an electric car because it considers that in the current state of technology, they cannot meet the needs of motorists. That is to say, its autonomy is very limited and the time necessary for its recharge exceedingly long. For Toyota there are two pitfalls that make an electric car unfeasible today. However, a car equipped with solid state batteries eliminate those two weaknesses.
In lithium-ion batteries, over time, that is, with the life cycles (charge and discharge), liquid lithium solidifies by eating the separator between the anode and the cathode creating dendrites (or cavities). These dendrites will cause a drop in battery performance and in extreme cases cause overheating, a short circuit and even an explosion.
A solid state battery provides more autonomy, very short recharge time and security. A solid-state battery can store three times more energy than a lithium-ion battery and recharges in less than an hour, according to John Goodenough’s team.
In addition, due to the solid state it is also safer , since in accident it would not catch fire – as it does with lithium-ion ones – and it also prevents the formation of dendrites, significantly lengthening its useful life and its safety (hence the interest of Samsung in this type of batteries …). In addition, the use of a crystal-based electrolyte would facilitate the mass production of these batteries, and thus help reduce their cost.
When will solid state batteries arrive
At the beginning of this investigation, one could think that it would still take several decades to see a practical application in the trade of these batteries. However, there are already many manufacturers who are filing patents related to solid-state batteries.
Samsung estimates that in two years, at the most, it will have a smartphonme with solid-state battery in commerce. Toyota, meanwhile, advances the date of 2022 for the first electric car with solid-state battery. If this type of battery fulfills its promises – autonomy, fast charging, safety, low cost – the electric car will definitely impose itself by condemning the internal combustion engine to death .