© NIO

© NIO

Supercharging can slash EV charging times but has technological challenges. Hence battery swapping is on the rise in China, with state support

To fully charge an electric vehicle (EV) battery in China today can take as little as 1.5–2.5 hours, or more than 10 hours, depending on whether slow or fast charging is used. Concerns about insufficient range and long charging times are the main reasons why many car owners are still slow to switch to EVs. EV makers understand that and have been exploring ways to slash charging times.

Supercharging is a popular choice. Pioneers in the field, including Tesla, Porsche and China’s BAIC BJEV, have been doubling down on supercharging technology with noticeable progress. Porsche’s first mass-produced EV model, Taycan, rolled out in 2019, could be charged at a record high rate of 270 kW, going from 5% to 88% charge in just 22.5 minutes, or adding 100km of range within five minutes.

But supercharging also faces a number of regulatory, technological and safety challenges. EV makers and third-party service providers in China are therefore also, with government support, developing the infrastructure for EV owners to easily exchange batteries on the go, instead of spending time on charging.

Chinese EV makers, including NYSE-listed NIO and BAIC BJEV, are ramping up efforts to build EV battery swapping stations to supplement their charging network. According to NIO’s founder Li Bin, the company is building a new battery swapping station in China every week, with plans to build 300 new stations next year.

Supercharging on the move

Xpeng Motors is the first Chinese EV maker to build a network of supercharging stations with power output of up to 120 kW each. Its first 100 supercharging stations became operational in March 2019 and plans are for 1,000 more stations, equipped with 10,000 charging piles, by end-2021.

In July 2019, NIO started operating its first supercharging station, comprising four 120 kW piles, at its Suzhou delivery center. Open only to NIO’s EVs, the superchargers take about 30 minutes to charge a 70 kWh NIO ES8 or ES6 model from 20% to 88%. EV owners can also use the NIO app to check charging status and control the charging process. 

By January this year, BAIC BJEV’s all-electric SUV EX3 achieved full charging in 20 minutes at a supercharging station run by the State Grid. 

TELD, China’s largest EV charging network operator and a ChiNext Market-listed company part of Qingdao Teruide Electrical Company, as well as other smaller local companies are also working to provide convenient supercharging services to EV owners. 

Tesla, which sold over 300,000 units of its Model 3 EV in China last year, plans to set up 4,000 supercharging piles across China by end-2020, doubling the total network it built in the last five years. Like its peers, most of Tesla’s superchargers are spread across more than 150 cities in China and are located in busy urban areas, but it is also building charging stations along highways in the countryside. 

Tech, supply chain hurdles 

According to Mu Xiaopeng, General Manager of the Electrical Engineering Center at TELD, the company’s supercharging piles can work at a maximum rate of 450 kW but rollout will depend on how fast national standards are issued. “We have already worked with [EV] carmakers for testing but the deployment depends on the progress of national standards,” he said

EV charging system operators want national standards on, among others, charging speed, battery capacity, types of charging connections and dispensing power of charging stations to reduce the risk of their charging facilities being compatible with onlya limited number of EV models in future. 

Like TELD, other EV charging system operators, such as Potevio New Energy and Star Charge, are also technologically ready but are still at the stage of pilot testing and will scale their services onlywhen national standards are unveiled.

The lack of national standards is only one of the factors that stand in the way of EV supercharging in China. EV makers also face technological challenges in making their cars ready for supercharging. They have to upgrade their existing EVmodels’ battery management and charging systems and voltage platforms, which are used to stabilize voltage during the charging process. Supercharging is known to hurt battery safety and longevity.

Tesla CTO JB Straubel thinks there is a tradeoff between charging speed and battery performance. “You cannot charge a high-energy battery pack at that rate [350 kW], unless it’s a very high kW battery pack,” he said. For that reason, Tesla will design its Supercharger V3 to have an output of 200–250 kW.

Another problem lies in the supply chain. “Only giant carmakers such as Porsche are able to work with their own auto parts suppliers to develop an EV model running an 800-volt infrastructurethat can take a 350 kW charge,” said Wang Min, technical director of EV charging at Xpeng Motors. 

Supercharging also has safety risks. In March 2017, a Tesla Model S caught fire at a Tesla supercharging station in Shanghai. In April, another Tesla model burst into flames, also in Shanghai, shortly after it was supercharged. An EV battery expert surnamed Wang thought it was a typical accident caused by thermal runaway of EV batteries. 

Although there is no proof that supercharging caused the accident, Wang suggested EV owners stay away from supercharging, or at least not use it often. “The stations work under high voltage and generate intense currents, which might cause battery fault and lead to fire,” said auto analyst Zhong Shi.

Upbeat on swapping

Considering the challenges of supercharging, some EV makers see battery swapping as a more feasible solution. Unlike Tesla, which shut its battery swap program in 2016 and switched to superchargers, some Chinese EV makers are now ramping up the deployment of battery swap stations to supplement their charging network.

In June, Miao Wei, China’s Minister of Industry and Information Technology, said the government will encourage EV battery swap services through measures, including tax cuts. Two months earlier, EV models with swappable batteries were exempted from the maximum price limit of RMB 300,000 for subsidies up to RMB 66,000 for each EV. Such policies have attracted a number of players into the market. In 2020 alone, about 1,000 companies working on EV battery swapping were registered in China.

Although battery swapping was tried in other countries, including the US and Israel, it has not gained a foothold there due to low return on investment in the construction of battery swapping stations. Battery swapping was also not well received in the US due to high cost and inconvenience. Tesla, for example, charged $60–$80 for a swap and required owners to retrieve their replaced battery to avoid possible complaints when car owners get a battery with shorter life expectancy. 

However, Chinese EV makers are more upbeat about battery swapping.  BAIC BJEV, for example, has plans to set up 300 swapping stations and roll out 30,000 EV models with swappable batteries within 2020. 

By June 2020, NIO had built 143 battery swap stations across the country. Although still far from its goal of 1,100 stations by end-2020, the company enabled a NIO EV owner to drive 2,300 km from Beijing to Shenzhen using only its battery swapping services, which it provides NIO EV owners for free, the whole process taking less than six minutes.

NIO has built an energy replenishment network comprising at-home charging piles, supercharging piles, mobile charging stations, battery swapping stations and public charging piles to satisfy the needs of different users In July, NIO even launched a battery leasing service, enabling drivers to buy a NIO EV without owning the battery pack. 

“In 2020, we will prioritize battery swapping over supercharging,” said Shen Fei, Vice President of Power Management at NIO. According to him, more EV makers will begin to explore the possibility of battery swapping this year. 

Edited by S. Mani

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