Sodium ion batteries are emerging as promising alternatives for low-mid range electric vehicles. The French company Tiamat Energy, backed by the Stellantis Group, has just announced its plans to build a sodium ion cell factory with a maximum production capacity of 5 GWh per year. This approach not only aims to reduce costs in electric mobility but also to counteract the problems of lithium, a critical component in current batteries.

This type of sodium-based batteries may be ideal for small electric cars, especially those that travel on stretches of road with the capacity to recharge on the move. In this context, the need for high energy capacity in cars could be significantly reduced.

Recently, this wireless charging technology has been implemented in Detroit, Michigan (USA), opening up the possibility of more compact batteries for electric vehicles. Sodium battery technology is based on the movement of ions between electrodes in a very similar way to lithium-ion batteries, but using sodium.

This concept, driven by its low cost and the availability of its main components, proposes a solution to the dependence on lithium, whose extraction is not free of negative environmental impacts and whose prices are volatile. Unlike lithium, sodium can be produced from an abundant material: salt. This raw material is widely available, easy to extract and affordable.

So far, these types of batteries have shown a lower energy density compared to lithium-ion batteries, which translates into a higher weight load to store the same amount of energy. Despite this challenge, leading battery manufacturers such as NorthVolt in Sweden and the alliance between BYD and Huaihai in China are intensifying their efforts to overcome this limitation.

Last November, BYD announced the construction of its first sodium-ion battery gigafactory in Xuzhou, Jiangsu province. With a capacity of 30 GWh per year and an investment of 1,284 million euros, BYD is expected to become the world’s leading supplier of sodium batteries for microcars.

A notable feature of sodium ion batteries is their ability to be fully discharged and stored or transported in this state without degradation, which adds versatility to their implementation in mobility applications. Unlike lithium-ion batteries, which can be irreversibly damaged in a complete discharge, this feature would simplify all battery transportation logistics, make them safer and further reduce the cost of marketing them.

However, widespread adoption of sodium-ion batteries faces significant challenges. The costs of components such as the separator and electrolyte can be considerably higher, which could result in a significant increase in the total cost of the battery.

Additionally, unlike lithium, sodium’s ability to charge and discharge can decrease rapidly over the life of the battery. That is why it is important to highlight the need for more research to address the technical aspects that allow the effective implementation of this emerging technology.

In parallel, the evolution of wireless charging could solve another critical problem: the charging infrastructure for electric vehicles. This method allows cars to be charged while driving, overcoming the limitations of conventional charging stations.

The implementation of this technology by the city of Detroit in collaboration with Ford and the company Electreon Wireless seeks not only to increase the convenience of charging but also to pave the way for vehicles with smaller batteries, since connected charging is not required as much. frequent. This pilot project involves the installation of 400 meters of inductive charging technology, offering a glimpse into the future of electric vehicle charging.

Inductive charging works by transferring energy through magnetic fields. Rails located on the road create an electromagnetic field that, when detected by a system compatible with induction charging in a car, transmits energy. This energy is converted into electrical energy that charges the car’s battery.

This approach could make battery packs more compact and therefore more affordable, facilitating the transition to electric mobility. Although the production process is expensive, a five-year evaluation will determine whether wireless charging is a viable alternative to conventional charging stations.

In Europe, the company Elonroad has developed a variant of electrified roads that has been deployed in several sections in the Swedish cities of Lund and Maristad. The operation is based on electrified metal strips on alternate sections of the road that generate electricity when a car is connected to them. In order for the vehicles to recharge their batteries while moving, they must have a system of deployable rails that act as connections, as if they were Scalextric cars.

In this sense we must also be cautious, since we must keep in mind that certain aspects of these developments are in their initial phases. While these advances are encouraging, they are still at a stage where commercial viability needs to be demonstrated on a larger scale.

These advances are very relevant for several reasons. On the one hand, they allow us to better manage energy and take advantage of transport infrastructure so that very long charges or cars with very large batteries are not needed and, therefore, so many mineral resources are not needed. On the other hand, they contribute to making electric vehicles more accessible and practical for a wider range of users.

Thus, the convergence of cars powered by smaller, cheaper sodium-ion batteries and electrified stretches of road in which vehicles recover energy while driving could represent a significant change in electric mobility.

This article was originally published on The Conversation.

Enrique García-Quismondo Hernáiz is a researcher in renewable energies, IMDEA ENERGÍA