Driving Nearly 300 Kilometers with the NIO ES8: Let's Talk About the Battery

NIO ES8: An Overview

The NIO ES8. a flagship model from one of China's renowned new electric vehicle manufacturers, has sparked much discussion recently. After my first public road test drive yesterday, I can finally address whether NIO can attract a large, happy user base.

Starting the Journey to Gubei Water Town

The story begins with my round trip to Gubei Water Town in the ES8.

An Evolved NIO

By now, if someone spends a lot of time talking about the exterior of the ES8 during a test drive, it would be a disservice to the readers, the camera, and the server storage space. Similarly well-known is the ES8's linear acceleration and deceleration performance. A press on the accelerator brings the car ahead infinitely close, while a tap on the brake makes the car behind fall back significantly.

Different from previous track test experiences, the real difference lies in the daily driving relevance of the steering and suspension. The air suspension, which felt overly tilted during turns in June, has completely changed its character on regular roads, providing excellent support while smoothing out common road bumps. The steering remains a bit too light, which could be very friendly for female users or in low-speed scenarios, but for those wanting to feel like a boss at the wheel:

Remember to switch to Sport mode.

User and media feedback has been consistently remembered. Unlike other brands, which often ask for feedback after each test drive but make no changes, NIO stands out.

Driving Nearly 300 Kilometers with the NIO ES8: Let's Talk About the Battery

A notable update is the silicone pad provided for the car key, preventing it from sliding during wireless charging, and slight adjustments to the key's weight, all based on previous feedback. This is just one example of the perceivable hardware updates.

From late June to yesterday, there have been six software updates, making the main instrument panel layout more reasonable with a speedometer on the left and an energy consumption meter on the right. The central control system's common functions are now usable, but there are still issues with recognizability and mixed UI operation logic.

However, breaking from conventional thinking, Nomi's natural language recognition is impressive. For instance, commands like "Can you turn on the steering wheel heating?" or "Can you turn off the steering wheel heating?" are executed accurately.

The FOTA function of the ES8 is not yet enabled, but users are surely eager for a stable platform before the software takes off.

Highway Range

The 141-kilometer route from NIO House in Zhongguancun to Gubei Water Town is quite convenient for electric vehicle users and frustrating for thrill-seekers.

Before hitting the highway, you navigate Beijing's congested Fourth Ring Road, where frequent stop-and-go traffic allows for significant energy recovery through regenerative braking. Once on the highway, the speed limit of 100km/h on the single-lane roads through the mountains is perfect for the ES8's energy-efficient 80-100km/h cruising range.

At the start, our ES8 was nearly fully charged, with a displayed remaining range of 340km.

- Driving at a steady 50km/h to the Beijing-Chengde Expressway toll station, we covered 18.2km, with a displayed consumption of 17km.

- At a steady 80km/h to Huairou Bridge, we covered 52km, with a displayed consumption of 55km.

- At a steady 90km/h to Miyun Service Area, we covered 81km, with a displayed consumption of 85km.

- At a steady 90km/h to Gubei Water Town, we covered 141km, with a displayed consumption of 152km.

Our ES8 had only been in use for five days, with a total range of 750km, indicating the battery was in prime condition. The remaining range is calculated based on previous driving habits, showing our predecessors were more aggressive drivers. We managed to reduce the average energy consumption from 30Wh/100km to 28.8Wh/100km by the end.

Overall, the discrepancy between the displayed range and the actual range was within 10%, with a cruising range of 300-310km at a steady 80-100km/h on the highway.

This matches the data provided by NIO's range calculator.

The Secret of the ES8 Battery Pack

Having and publicly sharing such an accurate range calculator relies on the consistency of the ES8 battery pack capacity and the investment in the BMS battery management system, according to Deng Xiaojia, Senior Director of NIO's Electric Energy Storage System.

In December 2008. the hosts of "Top Gear" mentioned during their test drive of Tesla's first product, the Roadster, that the car had over 6.000 batteries arranged under the seats, similar to those in laptops. Ten years later, laptops rarely have removable battery packs, and those that do no longer use cylindrical 18650 lithium batteries.

For NIO, founded in 2015. choosing the form factor of the battery cells for one of the most critical components of an electric vehicle was a significant decision.

Since NIO decided to establish a battery swap system from the start, the battery packs not only needed to operate longer and more frequently within the swap system but also ensure uniform use across different models. Therefore, NIO paid great attention to the safety and cycle life of the battery cells when designing the battery modules.

Among the three common battery cell types currently used in electric vehicles, NIO ultimately chose the VDA square cell produced by CATL with a capacity of 50Ah and an aluminum casing for adequate protection of the battery materials. The use of fewer battery cell modules helps control consistency and layout of the temperature control system.

Although hard-shell battery cells suffer in energy density due to the casing, the ES8's final battery module energy density of 135Wh/kg is comparable to the Tesla Model S/X 75D currently on sale, though lower than the 100D.

To ensure the battery pack operates within the optimal temperature range, the ES8 is equipped with a liquid-cooled constant temperature system. Each battery cell module has three temperature sensors, and aluminum liquid-cooled plates are laid under the entire battery module. This system can cool or heat the battery cells with high precision.

The ES8's BMS battery management system, consisting of the BMU (Battery Management Unit) and multiple CSCs (Cell Supervisory Controllers), ensures precise calculation capabilities using top-tier international supplier products.

The result is that the ES8 battery pack can retain over 80% capacity after 1.500 charge-discharge cycles under a 0.5C charge/1C discharge rate, simulating the most demanding user scenarios. This equates to a lifespan of 30 years with weekly charging.

I can almost hear your impatience by now. Many are clamoring to know the 120km/h constant speed range. Deng Xiaojia summarized it precisely:

"With a 70kWh battery module, the ES8's NEDC range is close to that of the Tesla Model S with a 75kWh battery (355km vs. 400km), surpasses in 80km/h constant speed range (393km vs. 389km), but falls short in the 120km/h constant speed range (226km vs. 280km)."

When asked for specific reasons, Deng explained that the ES8's energy storage system performs well in low wind resistance conditions, sometimes even better than the Model S. However, at 120km/h, the wind resistance increases significantly, and as a large SUV, the ES8's range is understandably shorter than the Model S, a sports sedan.

Pride in the Battery

If you're dissatisfied with the highway range, Tesla users might have to wait for the next car with a better power system, while ES8 owners might be able to upgrade to a higher capacity battery module next year.

Regarding NIO's choice of the battery swap model versus the supercharging station model advocated by brands like Tesla and Porsche, Deng Xiaojia noted that the entire battery energy storage system design balances multiple factors. While fast charging is a solution, it significantly impacts the battery's cycle life and safety.

Comparatively, the battery swap model offers faster energy replenishment under current infrastructure conditions and puts less pressure on the power grid.

To achieve a more efficient and durable battery swap experience, the ES8's battery pack has undergone substantial targeted design.

From a safety perspective, NIO manages the battery cells, modules, and packs through prevention, monitoring, and crisis control. The ES8's power battery system underwent 81 tests over two years and seven months, totaling 3 million kilometers.

The result is that the ES8 battery module can withstand rapid temperature changes from -40°C to 85°C, impact from a 1-meter free fall onto a steel plate, prolonged immersion in seawater, and even 130 seconds of continuous 590°C fire without exploding.

Ultimately, NIO claims the ES8 power battery system can support up to 10.000 battery swaps throughout its lifecycle.

To ensure the aforementioned battery module performance and the harmony with the swap system, NIO has achieved several technological innovations within the swap system, such as the water-cooled fast swap technology, which prevents coolant leakage during the swap process and automatically reconnects after the swap.

Deng Xiaojia stated that when asked about NIO's most successful innovation during the IPO process in the U.S., he proudly responded:

"The battery."

The Verdict: Driving Experience

Returning to the initial question about the driving experience, I’ll quote a former colleague now at PingWest:

"The ES8 creates a sense of luxury in the realm of electric vehicles."

As for how many users there will be? You'll have to drive it to find out.

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