The future of interchangeable batteries

Could interchangeable batteries be a solution to electric car charging?

One of the main challenges of electric vehicles is reducing the lengthy charging time. Among the solutions being considered by experts is the installation of battery swapping stations.

Electric cars are emerging as one of the main options for the transportation of the future, along with others such as hydrogen and low-carbon fuels. Today, as they become more widely used, the debate is about how to improve their efficiency and range to adapt them to our habits. One of the main challenges of this technology lies in its charging times: between one and six hours for normal mode and around 20-30 minutes in fast mode. In both cases, this is too long compared to traditional gasoline or diesel refueling.

According to a study by the Cetelem Engine Observatory, 27% of respondents cited recharging time as the factor with the biggest negative influence when considering buying an electric vehicle. In the quest for maximum efficiency, researchers around the world have been working for years on alternative charging methods, such as electromagnetic induction, which is already being tested with some success in Sweden.

The system is installed under roads and requires no wires for operation. The car drives and is constantly powered. Among its drawbacks are the prohibitively expensive 'hardware' and extremely intense magnetic fields, in addition to the need to adapt each country’s infrastructure.

Advantages of interchangeable batteries

Among the advantages of interchangeable batteries are the savings in time to recharge, extended useful life of cars, and lower vehicle prices.

Another option still under development but with signs of becoming a real possibility is exchanging batteries in electric vehicles. The process is as simple as removing the depleted battery and inserting a fully charged one in a matter of minutes. This option already has the experience of several tested initiatives, with varying degrees of satisfaction, over the past two decades. Among its advantages are the obvious time savings in recharging; the extension of cars’ useful life, since the battery would not be linked to an integrated energy tank; and a potentially lower vehicle price, as the cost of the battery would be an external service.

"One of the companies that took the replacement of energy accumulators most seriously was the startup Better Place, founded in 2007 and which went on to build the first electric charging network in the world in Israel," explained Carlos Bermúdez, business development manager for Electric Transportation at Repsol. This project unfortunately could not go ahead due to the high cost of replacement stations, the lack of standardization of batteries, and the lack of agreement among manufacturers to design cars that could work with their system.

Currently, one of the most advanced projects in this field is led by the startup Ample, based in San Francisco in the US, and in which Repsol itself has a share through its Corporate Venturing Fund. This young company has designed a battery exchange system based on a modular solution, which avoids the complete replacement of these accumulators. To do this, it has a cabinet that recharges the batteries and a robot that, in just ten minutes, removes only the used modules from the car and inserts the new ones.

"Replacing that small module is much faster, much more efficient, and much cheaper than replacing the entire battery," explained Carlos Bermúdez about Ample's system, which "also avoids needing to have such a large stock of batteries as before, with the complexities that this entails in terms of storage." The company is currently developing several pilot tests in the United States and Europe to test this technology and move on to a more commercial phase.

In Spain, the main initiative is Silence, a Catalan startup that has already successfully tested battery swapping in its own electric motorcycle models. The company has devised Europe's first battery station, where users can exchange a discharged battery for a charged one in just a few minutes. It will soon launch a pilot test in Barcelona, and in Madrid next year.

Also noteworthy in the international market are 'Power Swap Station 2.0', from the Chinese brand NIO. These battery swap stations are equipped with 14 slots that enable 312 processes per day, according to the company. Currently, this initiative—which only works with its own models—receives support from the Chinese government in an aim to reach 500 exchange points by the end of the year. The latest milestone for this Asian company is the installation of its first station in Norway and the announcement of further expansion in Germany.

The technological challenges of electric cars and interchangeable batteries are the focus of research

Despite the promise of the various battery exchange proposals, there are still challenges for this sustainable transportation option to become widespread. In the opinion of José María López, director of the University Institute for Automotive Research (Insia) at the Polytechnic University of Madrid, the first thing to overcome is standardization: "Currently, each manufacturer places the battery in a different location in the vehicle, giving it different sizes, capacities. and powers. This makes it impossible to exchange batteries between different models," he stated.

For the Insia director, there must also be an understanding that "the battery in electric cars is connected to the BMS (Battery Management System), which manages channeling all the car's operations and has direct impacts on proper operation when disconnected. Avoiding that connection to the BMS means there must be a modular exchange", he specified.

Lastly, this professor and doctor in industrial engineering believes that we must learn more about the effects of successive recharging. "At the moment, the number of charging cycles that a battery can withstand is being studied. It should be borne in mind that a new, but discharged battery is more reliable than an old one that has just been charged," he concluded. However, Lopez stresses the positive message that interchangeable batteries "are undoubtedly an attractive solution to be explored."

_{Published in El Confidencial}