The Chinese electric car manufacturer Nio is now also operating its stations for automated battery swapping in Europe. Swapping instead of charging is the motto. What's behind the concept? Everything you need to know at a glance.
Power Swap Station (PSS) from Nio in Waldlaubersheim (Rhineland-Palatinate) on the A61 motorway
Nio
Charging electric vehicles is often inconvenient and slow. As an alternative to connecting a charging cable, automated battery swapping in battery exchange stations has become established, particularly in China. The system is also becoming more and more widespread in Germany. Battery swapping stations are seen as a promising solution to the problem of short ranges and long charging times for electric cars. However, there are still some challenges to overcome. Here you will find the most background information on battery swapping technology and battery swapping stations.
What is Battery Swapping?
The principle of battery swapping is simple: The entire battery unit of the vehicle is decoupled, removed from the vehicle and replaced by a fully charged battery unit. The battery is charged outside the vehicle, independently of driving. "The fully charged battery is swapped with the empty vehicle battery as required and the vehicle is ready to drive again," summarizes Anton Karle in the German book chapter Charging and Charging Infrastructure. According to Karle, this battery change can theoretically be carried out in a similarly short time as refueling a petrol vehicle.
What Types of Battery Swapping Technology Are Available?
There are various techniques for replacing batteries. In the book chapter A Comprehensive Review on Electric Vehicle Battery Swapping Stations, the Springer authors led by Md Tahmid Hussain differentiate between four methods of battery swapping based on the position of the battery in the vehicle and the position at which the robot arm is attached:
Sideways battery replacement: The empty battery is pulled out horizontally from under the vehicle when the battery is changed and replaced with a fully charged one. As the battery can be changed from the side, the space and infrastructure required for a vertical battery changing station, which can be more expensive to install, is not needed. This technology is often used on delivery vans.
Battery change from below: This technique is used for vehicles with bottom-mounted batteries. The vehicle is placed on a raised platform by the changing station and the batteries are changed from below using an automation arm and other peripheral equipment, often located underground.
Rear seat battery swap: This method requires removing the rear seats of the vehicle and filling the space where the seats were located with a battery pack. Tesla had proposed this method, but the company ultimately decided against it. This battery swapping technique is suitable for vehicles where the batteries are located in the rear of the vehicle, which is often the case for cars with large trunks.
Vertical battery changing: The most common type of battery change. The entire battery is lifted out of the vehicle and replaced with a fully charged battery. This method requires special equipment and a special changing station with hydraulic lifting devices to remove and replace the heavy battery pack. However, vertical battery replacement is associated with some difficulties. The installation of the charging stations requires considerable investment in infrastructure, and standardization of battery sizes and interfaces for the different electric car models is also necessary. It can also take a while to complete the process – possibly longer than it takes to charge a battery at a fast charging station.
What are the Advantages of Battery Swapping?
Battery swapping stations are intended to avoid problems that are still preventing some consumers from switching to electric vehicles: range anxiety, long charging times and the lack of public charging stations for electric vehicles. According to the Springer authors led by Md Tahmid Hussain, although setting up a battery exchange station is expensive, it can be cheaper over time than conventional charging methods. This is because the batteries can be used more efficiently and over a longer period of time if they are changed regularly. According to Hussain et al., battery replacement can also extend the service life of the batteries, which reduces the overall need for new batteries. The adverse effects of battery production and disposal on the environment could be mitigated in this way.
Which Companies Rely on Battery Swapping Technology?
The first attempts at swapping stations were made by the Israeli start-up Better Place, Renault and Tesla. The Chinese car manufacturer Nio is currently one of the few electric vehicle manufacturers to offer battery swapping as an option for electric vehicles. Nio has launched a battery-as-a-service offer for customers in China and is also aiming to enter Europe with its vehicles featuring battery swap technology. Around 2,400 stations are already in operation worldwide, of which almost 40 are in the EU and eleven in Germany. The company is also constantly expanding the partner network for its battery swap system. Following Geely and Changang, with whom new standards are to be developed, JAC and Chery are now also on board. Nio is also testing bidirectional charging at its power swap stations.
The Chinese car manufacturer Geely is planning to install 5,000 battery swap stations for electric cars in China by 2025. However, the manufacturer is particularly focusing on swap stations for heavy commercial vehicles. The multinational automotive group Stellantis, meanwhile, is planning to integrate Ample's modular battery swapping solution into its electric vehicles. The Californian electric car manufacturer Fisker also wants to use Ample to develop an exchange battery system for the Fisker Ocean electric SUV. The Chinese battery manufacturer CATL is also involved in battery swapping: CATL subsidiary CAES (Contemporary Amperex Energy Service Technology) presented a battery swapping solution called Evogo in 2022.
Which User Groups are Interested in Swapping Batteries?
As the Springer authors led by Md Tahmid Hussain explain, the system could be used "where many similar vehicles of the same owner are in circulation, for example in vehicle fleets". Against the backdrop of the energy and transportation transition, for example, rechargeable batteries could be an economically attractive option for the cab industry in order to avoid long vehicle downtimes due to charging breaks. The Chinese-German joint venture InfraMobility-Dianba is working on this, as Dieter Flämig and Alexander Yu Li explain in the interview "In China, 80% of car manufacturers are switching to battery swapping". InfraMobility-Dianba is also cooperating with the French energy company TotalEnergies.
There is potential for a battery swap concept for commercial vehicles in particular: "On the one hand, in commercial vehicles the operational capacity plays a major role. [...] On the other hand, the design of trucks makes the use of replaceable batteries possible. The batteries are easily accessible and the chassis allows for the creation of a robust framework for the battery.," says Dr.-Ing. Michael Lindemann, Professor of Automotive Mechatronics at HTW Berlin, in the article "Fast Swapping instead of slow charging – A Comeback of the Interchangable Battery?" It would also be possible to define standardized battery modules that do not have to be designed for specific brands, says Lindemann. The scientist is working on the development of a quick-swap battery system for small vans in a joint project funded by the BMWi. Another example: In November 2023, a battery exchange station for heavy-duty e-commercial vehicles was opened in Lübbenau, Brandenburg, as part of the eHaul project. There, e-trucks can swap their empty 440 kWh batteries for full ones in around 10 minutes. Mitsubishi Fuso and Ample are testing the swap battery for e-trucks in Japan.
The swapping infrastructure solution is also suitable for small vehicles. The international Swappable Batteries Motorcycle Consortium (SBMC), founded in 2021, aims to develop a standardized battery and global standards for electric motorcycles and light electric vehicles.
Who Actually Owns the Removable Batteries?
The swap concepts only work with rental batteries. The individual energy storage units can be exchanged within an entire fleet and are therefore not rigidly assigned to one vehicle.
How many Rechargeable Batteries are Required to Operate a Station?
The following figures apply to Nio's swap system: Each Power Swap Station (PSS) is designed for up to 312 battery swaps per day with a maximum swap time of 5 minutes.
According to InfraMobility-Dianba, for 1,000 swaps per day (with a handling time of 1 to 1.5 minutes for Aulton/InfraDianba stations), an extra storage of 60 swap batteries is required (i.e. for 2,000 to 3,000 customers per station). These are to be provided once when the station is installed as an initial storage unit.
What Does the Switch Cost?
Concrete prices are only available from Nio so far. Nio customers who rent the battery of their vehicle in the "Battery-as-a-Service" (BaaS) model receive access to the Power Swap Stations (PSS). Until the end of March, customers can swap the battery free of charge and receive free electricity at the PSS. From April 2024, customers will receive two free swaps per month in the BaaS model, with the electricity received on top. This means that users only pay the energy difference between the new and returned battery. A swapping fee of 10 euros is charged from the third swap onwards. The new price model therefore comprises two components: The swapping service fee and the energy. Through the cooperation with RWE, Nio customers will pay a price that is comparable to around 0.39 euros per kWh.
As battery rental is a prerequisite for participation in Nio's Battery Swap, swapping will be expensive. With the Nio EL6, the 75 kWh battery costs 169 euros per month. The 100 kWh battery is offered for 289 euros per month.
What are the Challenges?
In order to be considered as a nationwide solution, battery exchange stations still have to overcome various challenges. Firstly, they would ideally have to be neutral in terms of car brand and battery brand. This includes the standardization of the batteries and their attachment. "Changing batteries would also be risky for the customer, as they could exchange a good battery for one in a much worse condition," says Springer author Anton Karle. Warranty and liability issues must therefore be clarified. In addition, the platforms are not designed for battery replacement; cell-to-chassis solutions are not compatible with the replaceable battery concept, as Professor Dr. Ferdinand Dudenhöffer, Director of the CAR-Center Automotive Research in Duisburg, explains in the German article Battery swapping stations for electric cars – China sets a new standard. According to Dudenhöffer, the trend towards fast charging and the ever-shorter charging times of electric cars are also hindering the implementation of the battery swap concept.
Added to this are the high costs and high capital requirements for installing the system. Deciding on the optimal location for a battery swap station and its capacity is also not trivial. According to the Springer authors led by Md Tahmid Hussain, it can be problematic to keep a supply of charged batteries on hand without knowing when the drivers will pick them up. Suitable battery management systems and planning tools as well as the use of predictive analyses to manage the battery stock are therefore necessary.
Interoperability is also a challenge: the battery exchange station relies on constant communication between the vehicle, battery storage, power grid, a photovoltaic system (if applicable) and the energy management and decision support system in order to function properly. The accessibility of batteries and chargers, cloud-based data storage and management, and the interaction between components to ensure interoperability must be comprehensively planned.
How can the Market Develop?
According to a report by MarketsandMarkets, the battery replacement market is expected to grow from USD 1.7 billion in 2022 to USD 11.8 billion in 2027, at a CAGR of 46.9 % during the forecast period. Rising demand for efficient, long-range and low-emission vehicles would boost the battery replacement market, according to the analysts. Government measures in countries such as India to promote battery replacement would drive the market in the future.
This is a partly automated translation of this German article.