New batteries at the start

New batteries at the start

A third of all new cars sold in China already have a plug, meaning they are purely electric or hybrid variants. The trend is rising sharply. In Europe, every political effort is being made to push electric cars onto the market; combustion engines are counted. Even though electric cars consist of significantly fewer parts, there are key differentiating features. While with combustion engines the question was whether diesel or gasoline, with electric vehicles it is the question of which battery technology is in the fuselage. The lithium-ion battery currently dominates. But other technologies are trying to get involved, especially sodium-ion batteries and lithium iron phosphate batteries. As is so often the case, there is currently no one battery technology that can do everything: high energy density, high charging currents, high cycle stability, flame retardant, and all of this at the lowest price with a 100 percent recycling rate and easily accessible raw materials. If all of this were combined in one technology, e-mobility would no longer have any critics. But the fact is: every battery technology has its specific advantages and disadvantages. These must be weighed up carefully in order to be able to select the best technology for the respective application. However, there are massive conflicting goals in electric cars: On the one hand, the range should be as long as possible, but the car should be cheap to buy for the masses. As of today, that's not possible! But if you shift the goals in one direction or the other, alternative battery technologies can already offer exciting advantages.

A rule of thumb is: the larger the battery, the longer the range. But also: the higher the price. Why does the lithium-ion battery currently have such a dominant position? We ask researcher Marcus Jahn, Head of Competence Unit Battery Technologies at the Austrian Institute of Technology (AIT), and a real expert on the various battery technologies. "We have known about the lithium-ion technology that we are currently using since the early 1990s. However, we have now been able to make the cells significantly more powerful. Nevertheless, we are already operating close to the physical limit with this type of battery. We can no longer expect any significant leaps here." Lithium-ion batteries have some undeniable advantages: they offer high power density, have a solid lifespan of around 1,000 charging cycles and are reasonably safe to build. The downside: low temperatures are not your friend, recycling is currently still very expensive - because it is complex - and above all they use rare materials such as nickel, manganese and cobalt. Not to mention that lithium mining is very polluting and most deposits are known in South America and Australia, which also opens up a “geopolitical dependency” – something that researcher Jahn does not describe.

If the battery becomes cheaper, the entire electric car becomes cheaper. Therefore, intensive research is being carried out into alternatives. There are currently two technologies that could possibly - from certain perspectives - compete with the lithium-ion battery: the lithium iron phosphate battery (LFP for short) or the sodium-ion batteries. Both variants have specific advantages and disadvantages. Ford is already using the LFP battery in some models because, according to the manufacturer, it offers a price advantage of around 15 percent. Further advantages: High cycle stability, less sensitive to temperature, does not require rare raw materials and is almost 100 percent recyclable, only the electrolyte has to be disposed of. This means that LFP batteries could make starting an electric car more affordable. The downside: The energy density is lower, so more cells are needed for the same range as with a lithium-ion battery. This would increase the weight again - and also the price. However, if this technology is used in vehicles that do not have to achieve the maximum range, it offers a clear cost and environmental advantage. Researcher Marcus Jahn puts the difference in energy density at around 20 percent. “The goal here should not be to swap the lithium-ion battery 1:1 for the LFP battery, but rather the technology can be a cost-effective alternative if used correctly if the intended purpose is chosen accordingly,” says the researcher.

Sodium-ion batteries are currently making a name for themselves in China and are enjoying growing popularity. AIT researcher Marcus Jahn can also attest to the cells' very positive properties: "The sodium-ion battery has been intensively researched for around seven years. The technology was originally intended for stationary operation because it allows attractive costs per kilowatt hour. Other advantages: Sodium is easily available worldwide, which reduces costs. In addition, the cells can be manufactured in exactly the same way as lithium-ion batteries, even on the same production lines. Practically only the lithium is replaced by sodium." But on the one hand, this cell also requires rare raw materials apart from lithium and cannot be integrated with lithium in the same recycling process. But the sticking point is different: the energy density is lower, around a quarter of it is missing from the lithium cell. Means: The price advantage is again bought at the expense of the range. But battery researcher Marcus Jahn tries to explain why this technology still has potential: "We must not forget that the demand for electric cars will increase significantly now and in the future. So you quickly need a lot of batteries, and not every electric car user needs a range of 700 kilometers. Here the sodium-ion battery can be a good compromise between range, availability and price." At the end of our interview, we asked the researcher what type of battery we will use in the medium term, in the next five years. The answer: “The lithium-ion type will dominate until then.” But what comes next is still an open question based on the current state of research.

Lithium ion

+ high energy density

+ solid cycle stability

+ extensively researched

- expensive

– resource-intensive production

– complex recycling

Lithium iron phosphate

+ cheaper

+ very high cycle stability

+ less sensitive to temperature

– lower energy density

Sodium ions

+ Sodium is plentiful and easy to obtain

+ therefore cheaper

+ Can be produced on lithium-ion production lines

– lower energy density

– up to lithium, which is similarly resource-intensive to produce

– complex recycling