Can power batteries achieve both high energy density and ultra-fast charging?
Microvast, initially known for its fast-charging batteries, has been exploring this technology under current and future conditions. At the 2019 Shanghai Auto Show, Microvast showcased three batteries designed specifically for pure electric passenger vehicles, featuring 1C, 1.6c-1.8c, and 2C fast-charging capabilities; they also boast energy densities of 270Wh/kg, 225Wh/kg, and 205Wh/kg, respectively.
That's not enough, you might say. Can't it be more powerful and charge faster?
In response, Guo Shengchang, chief designer of Microvast battery systems, said that Microvast's previous products had stronger fast charging capabilities, but the products developed based on the operational needs of the passenger vehicle market take into account the characteristics of low cost, standardization, and performance diversification.
Looking to the future, there are no commercially viable new battery material systems that can significantly improve energy density. Moreover, increasing energy density often has a negative impact on fast charging capabilities. Therefore, Microvast's strategy is to avoid both extremes in energy density and fast charging, and instead balance energy density, fast charging capabilities, and cost.
1. Entering the passenger vehicle market
Microvast is one of the established power battery companies, founded in 2006. Previously, its products were known for fast charging and were mainly used in commercial vehicles.
In China, the earliest visible mass application of Microvast power batteries was in April 2011. The first batch of six fast-charging pure electric buses officially began operation in Chongqing. These buses, manufactured by Hengtong Bus, used Microvast power batteries and could be charged in less than 10 minutes. At that time, the deployment of these fast-charging buses marked the official start of the commercial operation of fast-charging buses in China. Later, Chongqing Public Transport purchased another 1,500 fast-charging buses.
Microvast supplies its fast-charging batteries to electric and plug-in hybrid vehicles both domestically and internationally. In recent years, it has developed and produced at least four generations of batteries, with sales spanning across the globe, reaching as far as the UK, Belgium, New Zealand, and Moscow. Major projects include the battery supply for over a thousand red double-decker buses in London and 120 hybrid buses in Belgium.
According to Microvast's statistics, by the end of 2018, the total number of commercial vehicles equipped with Microvast battery systems worldwide reached 25,000, with a cumulative operating mileage of over 2.3 billion kilometers. They operated continuously in more than 160 cities in 16 countries around the world, maintaining a record of zero operational safety accidents.
In 2018, Microvast began to focus on the passenger vehicle market. In September 2018, Microvast appeared in the list of pure electric passenger vehicle suppliers.
The power battery for the newly added Changan Eado EV (SC7003AKBEV) in the "Recommended Models for the Promotion and Application of New Energy Vehicles (Batch 9, 2018)" released that month was manufactured by Microvast Power.
In March 2019, the second batch of the "Recommended Models for the Promotion and Application of New Energy Vehicles" was released, and Microvast Power once again entered the passenger vehicle market. The Chongqing Lifan pure electric passenger vehicle, which uses Microvast Power battery cells, has a battery system energy density of 160Wh/kg and a range of 400km. According to the new subsidy policy in 2019, both of these models are within the scope of national subsidies, receiving subsidies of 14,400 yuan and 25,000 yuan respectively.
Entering the supply chain for Changan and Lifan signifies a breakthrough for Microvast's power battery business. Behind this lies the shift in product development from fast-charging models to balanced performance models that passenger vehicles require.
2. Balanced performance across multiple aspects
Guo Shengchang believes that there are two main pain points for pure electric passenger vehicles: short driving range and long charging time. To address this, Microvast has launched a passenger vehicle power battery that balances energy density and fast charging capability. Furthermore, it offers three models based on a combination of high and low energy density and fast charging capability, allowing different automakers to choose the appropriate option.
The 52Ah battery boasts an energy density of 270Wh/kg, placing it on par with the highest energy density products currently mass-produced in China. Guo Shengchang stated that such a battery can support a range of 400 kilometers, essentially putting it on par with gasoline-powered vehicles.
The 48Ah product is suitable for ride-hailing and taxi vehicles, and the system energy density can reach 140Wh/kg, providing a certain driving range. It can also be fast-charged to meet the needs of ride-hailing and taxi operations.
The 44Ah product, used in taxis with higher operating mileage, can be fast charged from 0% to 80% in 20 minutes and fully charged to 100% in 30 minutes, meeting the needs of all-weather operation.
Guo Shengchang believes that although these three products have different power densities and energy densities, they are the same size, all of which are VDA size, suitable for the operational needs of the passenger car market, and take into account the characteristics of low cost, standardization, and performance versatility.
3. Higher energy and faster charging?
In the future, Microvast will continue its efforts to develop batteries with relatively high specific energy and relatively fast charging capabilities.
According to information previously disclosed by the head of Microvast, in the fourth quarter of 2020, Microvast also planned to mass-produce products with a capacity of 300Wh/kg, 1C charge-discharge, and a cycle life of more than 1200 cycles.
By the fourth quarter of 2021, Microvast plans to launch a 350Wh/kg battery that can be charged to 40% capacity in 15 minutes at a 4C rate with a mid-stage SOC and has a cycle life of over 800 cycles.
Both products still use ternary lithium-ion batteries with silicon-carbon anodes. Guo Shengchang stated that the future development of new material systems that significantly improve energy density remains to be seen. Since the pursuit of high specific energy generally has a negative impact on fast charging capabilities, Microvast's product direction will continue to focus on balancing energy density and power density while striving for low cost.
