More autonomy, less weight, faster charging, increased safety… the solid battery is often presented as the future of the electric car. Almost all automotive brands are therefore working on this breakthrough, even if its massive arrival is not imminent. State of play.
After the transition from lead to lithium-ion, is the electric car about to undergo a new revolution? In any case, this is what most manufacturers hope for by investing in so-called solid batteries, as opposed to current accumulators with liquid electrolyte. But despite the increasing number of announcements, this technology remains unknown to the general public. The fault is both its apparent complexity and a still unclear launch schedule. Some, like Tesla, are even skeptical and minimize the supposed advantages of this type of battery, while few imagine democratization before the middle of the decade. The argus offers you to take stock.
A solid battery, what is it?
To fully understand what a solid battery is, you must already know how a classic battery works. It invariably stores electricity which it is then able to restore or recover thanks to a chemical reaction called oxidation-reduction. For this, it is necessary to circulate electrons between two electrodes, the cathode, which represents the positive pole, and the anode, which is the negative pole. These two terminals are immersed in a conductive substance, the electrolyte. It is he who allows the ions, these atoms having gained or lost one or more electrons, to move from one side to the other, according to the phases of charge and discharge. In a lithium-ion battery, this electrolyte is liquid.
With the all-solid state battery (ASSB), you guessed it, the goal would be for it to use a solid material, which can be in the form of a polymer or some kind of ceramic. This has advantages… and disadvantages. Please note, there are also so-called semi-solid batteries, which retain liquid components and are thus easier to industrialise. It is the choice of the young Chinese brand Nio for its ET5 and ET7 sedans, and it seems that its compatriot Dongfeng has carried out the same for the fleet of 50 E70 taxis which it has just launched with great fanfare in January 2022… even if his communication could suggest otherwise. Here we will focus only on the even more promising “real” solid state batteries.
What are the theoretical advantages?
- Increased security: the solid electrolyte is not flammable, even when strongly heated. This could thus put an end to the cases of electric car fires which have sometimes hit the headlines, even if they remain quite rare in absolute terms.
- Faster charging: this advantage partly depends on the previous one. Since the risks of overheating have been removed, it would become easier to accelerate the recharging speed. The Renault-Nissan alliance thus recently mentioned a time to refuel electricity divided squarely by three.
- Better energy density: thanks to the use of innovative high-voltage materials, it would become possible to store more energy in the same size and weight. Especially since the cooling system would no longer need to be so complex. We could thus get out of the vicious circle which pushes to install ever larger and heavier batteries to gain autonomy. Volkswagen evokes the possibility of exceeding the 1,000 km radius of action.
- Lower costs: on this point, lithium-ion batteries have not yet said their last word. All manufacturers are still working to make them cheaper in the coming years, to move towards price parity between thermal and electric cars. But the current inflation in the cost of raw materials makes this objective increasingly uncertain. By allowing the use of fewer materials, thanks to its better energy density, and by avoiding the use of expensive lithium for its anode, the solid-state battery could do better. Nissan thus evokes prices divided by two!
- Better life: as you may have already noticed on your smartphone, a lithium-ion battery loses capacity over time. Electric cars are no exception to this phenomenon, which is accentuated among users who multiply fast charges. According to QuantumScape, associated in particular with Volkswagen, the all-solid battery would make it possible to virtually eliminate this unfortunate defect.
Why is it taking so long to arrive?
With such an anthology of theoretical advantages, one might wonder why the all-solid-state battery hasn’t already become the norm. But there are still many obstacles to overcome to be able to offer it in series. It is indeed very difficult to design a solid electrolyte which is at the same time very stable, chemically inert and very conductive. If the Bluecar Bolloré battery is for example already of the all-solid type, its polymer electrolyte must be heated to 60/70 degrees permanently. A constraint that requires vehicles to be left plugged in almost all the time, otherwise they will quickly be found empty! Chemists around the world are thus working on the right choice and the right dosage of the materials used, without a consensus really emerging.
The promises of an increased lifespan are also far from being fulfilled for the moment. On the contrary: according to Toyota, which is one of the most advanced car manufacturers in this field, this would be the major problem of the prototypes tested by the brand today. Finally, the large-scale production of these new type accumulators at a reasonable cost is also a real challenge. For now, no manufacturer is really capable of it, and most of the solid-state batteries that already exist would cost eight times more than their equivalent lithium-ion with liquid electrolyte, according to experts quoted by Reuters. This gives an idea of the path that remains to be traveled.
The solid-state battery, when is it?
With so many unknowns to resolve, builders generally avoid giving a timeline. Most communicate on a serial arrival at best for the second half of this decade, when others, like BMW, are counting on 2030 instead. One of the most optimistic is Stellantis, which announces that it wants “introduce solid electrolyte battery technology from 2026”. Toyota’s premium subsidiary, Lexus, for its part recently mentioned a “possible use of an all-solid-state battery” on his future supercar, replacing the LFA. But this formulation does not oblige it to anything and the launch date of this sports car, which should be produced in very limited quantities like its predecessor, is still unclear.
“It is finally still Nissan which is the most precise: “by the middle of the year 2028, the objective is to produce ASSB technology in series”, recently announced the Japanese manufacturer.“
Which manufacturers will offer solid-state battery vehicles?
As we have seen, most manufacturers are very interested in solid-state batteries. Faced with the complexity of the obstacles to overcome, only Honda or Nissan seem to have chosen 100% internal development for the moment. The others have all signed partnerships with specialized companies. Including Toyota which entered into a joint venture with Panasonic to complement the work of its own engineering teams. Stellantis, the result of the merger of PSA Peugeot-Citroën and Fiat-Chrysler, has for its part set its sights on the American start-up Factorial, also chosen by Mercedes. The Etoile brand even doubled the bet by having invested just afterwards in Prologium, the “the world’s first battery company to mass-produce solid-state lithium ceramic batteries” . Hyundai-Kia also plays on two tables: that of Factorial on the one hand and that of a company called Ionic Material on the other.
BMW and Ford are themselves present in the capital of another American company with a very telling name, Solid Power, which is to inaugurate a pilot production line this year. Volkswagen’s choice fell on QuantumScape, founded in 2010 in California, and General Motors will be able to rely on a joint venture with Posco Chemical. Be careful also not to forget the Chinese manufacturers. We have seen that Nio and Dongfeng have already launched semi-solid batteries, and the Middle Kingdom remains one of the world’s leading producers and designers of accumulators. But Geely, known in Europe as the owner of Volvo and Lotus, does not seem to be really working on the subject for the moment. The group prefers to invest in improvements in liquid electrolyte technologies. He is not the only one in this case. Among the brand absent in this great race for the solid battery, we indeed find Tesla! Is the American manufacturer right to be so cautious or is it, on the contrary, taking the risk of losing all the lead it had gained over its rivals? We will have to wait until at least the middle of the decade to find out.
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