On the morning of December 17. 2023. at 6:30 AM, NIO's CEO, William Li, took on the challenge of a 1.000-kilometer real-world range test in an electric vehicle, live-streaming the event. After 14 hours of driving, the test vehicle arrived in Xiamen with 3% battery remaining, having covered 1.044 kilometers. Undoubtedly, William Li personally showcasing his product in a live stream not only met the 1.000-kilometer goal but also succeeded in both marketing and product testing. However, the true star of this event was not the car itself but the 150 kWh battery pack under the NIO ET7.
Let’s go back to January 9. 2021. when NIO announced at the 2020 NIO Day in Chengdu that it would officially launch a 150 kWh battery pack using solid-state battery technology, with deliveries expected to begin in the fourth quarter of 2022. Now, as we approach the end of the fourth quarter of 2023. new updates have finally emerged regarding NIO's 150 kWh battery pack. On December 16. William Li announced on his social media account, "The 150 kWh battery pack is here, thank you for waiting!" However, what arrived was a semi-solid-state battery. Despite this, the fact that it took so long for NIO to introduce the semi-solid-state battery indicates the challenges involved, resulting in a year-long delay. Nonetheless, the long-dreamed-of solution to range anxiety is now a reality. So, what exactly is a semi-solid-state battery, and what are its advantages?
"Range Anxiety"—The Biggest Obstacle to Electric Vehicle Development
First, let's clarify a fact: although electric vehicles have achieved remarkable progress, "range anxiety" has remained the biggest obstacle to their widespread adoption. This anxiety is primarily caused by two factors: the technical bottleneck of battery technology, which is difficult to overcome, and the instability caused by temperature fluctuations, which fails to provide users with a "sense of security" when estimating range. Secondly, the insufficient density of charging and battery-swapping stations, unlike the ubiquitous gas stations, and the high cost of charging time, coupled with the lack of standardized charging protocols, also hinder widespread adoption. The latter issue is a long-term challenge that involves the maintenance and operation of infrastructure, making it difficult to achieve ideal results quickly. Therefore, improving battery technology seems to be the most viable path for the current development of electric vehicles, and the emergence of semi-solid-state batteries may provide a definitive solution.
The Structure and Advantages of Semi-Solid-State Batteries
A semi-solid-state battery refers to a battery where one electrode contains no liquid electrolyte while the other does, or where the solid electrolyte mass or volume makes up half of the total electrolyte mass or volume in the battery. Compared to the widely used fully liquid electrolyte lithium batteries, these batteries, which incorporate semi-solid or solid electrolytes, can effectively prevent safety issues such as fires caused by liquid leakage. Additionally, semi-solid-state batteries offer better thermal stability, making them less prone to decomposition under high temperatures, thereby ensuring long-term stability. Furthermore, semi-solid-state batteries boast higher energy density. Currently, mainstream lithium iron phosphate batteries have an energy density of around 200 Wh/kg, while ternary lithium batteries offer around 250 Wh/kg. The Weilan New Energy semi-solid-state battery in the NIO ET7 has an energy density of 360 Wh/kg, enabling a greater energy capacity and longer range.
While we've been discussing "semi-solid-state batteries," it's worth noting that the theoretical advantages of fully solid-state batteries are even greater. So why aren't fully solid-state batteries being used? The main challenges lie in the technical difficulties. For example, the ionic conductivity of solid electrolytes is much lower than that of liquid electrolytes, leading to increased internal resistance, poorer battery cycle life, and lower rate performance. Additionally, the high cost of fully solid-state batteries also hinders their commercialization. Currently, the supply chain for liquid lithium batteries is very mature, enabling the production of cost-effective, high-performance lithium batteries, whereas the supply chain for fully solid-state batteries is not yet well established. Until fully solid-state batteries are truly ready, semi-solid-state batteries, which combine the advantages of both solid and liquid batteries, are the best option.
Why Don’t Fuel-Powered Cars Have "Range Anxiety"?
Now that we understand what semi-solid-state batteries are, let's think about why fuel-powered cars don’t experience "range anxiety." Fuel-powered cars also have large engines, and some vehicles have a full-tank range that is far less than that of current mainstream electric vehicles. The main reason is the widespread presence of gas stations, which provide drivers with the confidence that they can refuel anywhere. The same logic can be applied to electric vehicles. Since the layout of charging infrastructure and the reduction of charging times cannot be quickly resolved, the introduction of semi-solid-state batteries can increase energy capacity, extend the range per charge, and reduce the frequency of recharging. This, in turn, can mitigate the safety and temperature sensitivity issues associated with batteries. Additionally, as charging and battery-swapping facilities become more widespread, range anxiety can be further alleviated. If you're wondering about fully solid-state batteries, they first require overcoming technical challenges, and second, the high cost raises the barrier to entry for consumers. In the future, with more comprehensive charging and swapping infrastructure, longer ranges might be unnecessary, potentially leading to a situation where overengineering becomes redundant.
Current Applications of Semi-Solid-State Batteries
Through his live-streamed event, William Li demonstrated the “muscle” of NIO’s technology, showing for the first time that semi-solid-state batteries can achieve over 1.000 kilometers of real-world range in winter's low temperatures. However, semi-solid-state batteries are not exclusive to NIO. Major automakers are competing in this "race." As one of the leading domestic car manufacturers, SAIC Motor has been at the forefront. At the Fifth World New Energy Vehicle Congress held on December 7. SAIC Motor's Vice President and Chief Engineer, Zuo Simian, confirmed that semi-solid-state batteries would be mass-produced and applied in different SAIC models between 2024 and 2025. For example, the production version of SAIC Maxus's GST concept pickup might be equipped with a semi-solid-state battery to achieve even more impressive performance.
The GST concept pickup was unveiled at the 2023 Shanghai Auto Show, and the production version is expected to be launched this year. It is said that the production model will retain much of the concept car's design, meaning that the GST concept car's "new electrified mech" aesthetic, "Bauhaus" utilitarian layout, pillarless suicide doors, electric retractable side steps, and innovative four-seat configuration could all appear in the production model, blending science fiction with traditional pickup design. Of course, one of the GST's biggest highlights, relevant to today's discussion, is its semi-solid-state battery, which could enable a pure electric pickup to achieve over 1.000 kilometers of range, while the CTC (cell-to-chassis) architecture provides additional battery protection, making it more suitable for off-road driving.
More battery capacity also allows the GST to unleash its full performance potential. For example, its four-motor distributed drive system delivers 1.000 horsepower and an astounding 14.000 Nm of peak torque at the wheels, making this robust pickup capable of 0-100 km/h acceleration in just three seconds. If the production model can deliver these technologies, the GST could truly be the "most powerful pickup on the planet."
In conclusion, the reason why semi-solid-state batteries may be the final solution to electric vehicle "range anxiety" is that they can push real-world range beyond 1.000 kilometers, meeting long-distance driving needs while easily handling urban commuting. Furthermore, if battery-driven new energy is indeed the foreseeable future, then the layout of charging and swapping stations will become more comprehensive, reducing the reliance on ultra-long-range fully solid-state batteries. Thus, the advent of semi-solid-state batteries may be the best answer to overcoming the last major hurdle for electric vehicles.
