M An can be on the subject of electromobility as you like, the bottom line is two currently unpleasant questions: Where does the electricity come from for driving and how do we take it with us? clear: wind and sun instead of oil, gas and coal should satisfy our hunger for energy in the future. The status quo of the German electricity mix is still sobering - we still emit 489 grams of CO2 per kilowatt hour of electricity (estimates by the Federal Environment Agency for 2017). But the progress can be seen: in 2016 it was still 516 g /kWh. It is slowed down by the same problem as the electric car: How do you store electricity from regenerative sources for the times when the sun isn't shining or the wind isn't blowing?
Cell chemistry of the batteries: Lithium is set
In electric cars, lithium-ion batteries currently store the electrical energy. Their energy density is around 100 to 150 watt hours per kilogram (Wh /kg). For comparison: the energy density of diesel and gasoline is around 11,000 to around 12,000 Wh /kg, which is around a factor of 100 higher. One liter of diesel has the energy content of 9,912 Wh (9,912 kWh). A Tesla Model S P100 only has around 10 liters of diesel on board. In other words: The Tesla has a very considerable range with the equivalent of 10 liters of diesel. This is due to the significantly better efficiency of the electric car. The tank-to-well balance, i.e. the efficiency from the kinetic energy carried and converted in the tank or battery, is around a factor of three better in the electric car, i.e. the Model S carries 30 liters of fuel with it. The comparatively small amount of energy would be bearable when chargingas fast as refueling. But even the best electric cars are currently still about six times slower.
Lithium (Li) is set because it has the highest standard potential of all chemical elements. Standard potential means the possible voltage difference between ions (charged particles, Li +) and elementary form (Li) in comparison with a hydrogen electrode.
Lithium is the lightest of all metals and very reactive. When it comes into contact with the skin, it reacts with moisture and leads to severe chemical burns and burns. Therefore, only non-aqueous electrolyte solutions or solid electrolytes are used in lithium batteries. The electrolyte, i.e. the material between the electrodes of a battery through which the ions migrate, is also of central importance for the performance of the battery. And because lithium seems to be the best active material, hopes for increased battery performance are linked to better substances for electrolyte and electrode material.
The solid-state battery is also a lithium-ion battery
Instead of one viscous medium, solid-state batteries are supposed to work with - as the name suggests - solid material between the electrodes. The first prototypes already have an energy density of 460 Wh /kg (megajoules per kilogram), i.e. three times that of the maximum 150 Wh /kg in lithium-ion batteries currently in use.
Solid-state batteries allow a more compact cell design, so they not only need less weight, but also less space for the same energy. Lithium-polymer solid-state batteries, for example, allow close contact between the electrode and electrolyte without the reactive lithium damaging the surrounding material.
- Solid-state batteries are less sensitive to temperature. The complex temperature management of lithium-ion batteries with liquid electrolyte can largely be dispensed with. That toosaves space and weight.
- Solid-state batteries are much more cycle-resistant, i.e. they deal better with many charging cycles and are therefore more durable.
- Solid electrolytes consist of inorganic substances and are non-flammable and thermal more stable. There is no risk of electrolyte fluid escaping from leaks and therefore no thermal 'runaway' or the risk of battery fires that are difficult to extinguish Charge can migrate through the cell. This not only happens when the ions move through the electrolyte, which the right solids are well suited for. However, high currents at the transition between two different solids (here from the electrolyte to the electrode material) are difficult.
More performance and longevity with inorganic electrolyte
With an inorganic electrolyte, the Swiss company Innolith wants to make great progress, especially in terms of durability, and build batteries that are non-flammable, although the electrolyte is liquid in this case. The liquid contains “three main components. One is lithium chloride, one is aluminum chloride, and one is sulfur dioxide. 'None of these substances can burn', as Innolith President Alan Greenshields explained in an interview with 'Wired'.
On April 4, 2019, Innolith AG announced on its website that the company was participating in the Development of the world's first rechargeable battery with an energy density of an incredible 1,000 Wh /kg. That would be three times as much as today's lithium-ion batteries in e-cars. The Innolith Energy Battery, developed in the company's German laboratory in Bruchsal, is intended to enable electric cars to cover more than 1,000 kilometers with a single battery charge. In addition, the new super battery should also significantly reduce costs, since it does not require expensive exotic materials (such as cobalt as cathode material).
Cell chemistry is the search forthe right material
Apparently Innolith also uses other electrode materials in the chemical structure of its batteries which can store the lithium ions particularly well without the (in batteries) mostly crystalline structure of the stored substance changing significantly. This process is called intercalation and is very important for the charge transfer in the battery, i.e. for its performance. In lithium-ion batteries, the lithium ions are deposited in a different (intercalation) material on each electrode. In addition to the flow of ions through the electrolyte and a membrane, the charge transfer (current flow) works better, the easier it is for the lithium ions to store. Apparently Innolith has identified particularly suitable materials and has thus been able to increase the energy content 'of each battery cell to previously impossible values'.
According to its own statements, Innolith initially wants to bring its Energy Battery onto the market via pilot production in Germany, followed of license partnerships with leading battery and automobile manufacturers. According to the company, the development and marketing of the new type of battery will take between three and five years.
However, Innolith is already the third company to try its hand at the super battery with inorganic electrolyte. There are two predecessor startups in which Alan Greenshields was also involved: Fortu and Alevo, both had to file for bankruptcy (2014 and 2017).
The first Innolith battery is already working
Innolith has taken over the patents and an important location from the Alevo bankruptcy estate, said Managing Director Sergey Buchin also at Wired: The Innolith laboratory and test center in Bruchsal with around 60 scientists and technicians. According to Buchin, Alevo failed due to enormous production costs, but at least delivered a finished battery. In January 2017, Alevo delivered a so-called GridBank (ie a 'network storage') to Maryland. The two gigawatt buffer energy storage device is as big as a ship's container.
So it is not suitable for cars, but at least for the storage of alternatively generated electricity as described above. One can easily imagine that there is still a long way to go before miniaturization for automotive purposes. But the durability seems convincing. The giant battery is still in operation and has already gone through a few thousand charging cycles, says Buchin. The battery should withstand 50,000 charges, five to ten times more than current lithium-ion batteries.