Tech Talk | How to Turn Electric Vehicles into Powerhouses of Endurance

Often improvements to NIO's Banyan Smart EV operating system can results in users seeing improvements in ET5 performance, in terms of range and energy consumption. With a Long Range battery pack, the ET5 can achieve an ultra-long range performance of up to 590km under WLTP comprehensive conditions, with a leading energy consumption of up to 18.6 kWh per 100km.

What are the main areas where pure electric cars consume electricity? How can we make a NIO vehicle more energy-efficient while keeping it comfortable? And during day to day driving, what are some easy ways to help your battery last longer?

In this issue of Tech Talk, we invited H. Zhu, Experience Manager from our China office, and Marius Keil, Experience Manager from our European team, to analyze smart electric vehicle energy consumption and share the technical details behind the exceptional technical capabilities of the ET5 and strategies for enhancing energy efficiency.

How is the electricity in electric vehicles utilized?

Fuel consumption per 100 kilometers (L/100km) is a key reference indicator for fuel vehicle users when purchasing cars. It represents the amount of fuel consumed by a fuel vehicle per 100 kilometers in standard tests, which includes not only operating the generator via the internal combustion engine to produce electricity, but also charging the battery for auxiliary uses such as lighting, air conditioning, and other electrical features. Therefore, what we call "energy consumption" reflects not only driving energy consumption but also the overall energy usage throughout the journey.

To achieve various performance, safety, comfort, and entertainment experiences, smart electric vehicles incorporate many electronic components. Taking the NIO ET5 as an example, it includes 33 high-performance sensor including ultra-long-distance high-precision LiDAR, a dual-motor intelligent four-wheel-drive system with power and performance on par with supercars, 4 Orin-X chips boasting an industry-leading 1,016 TOPS (tera operations per second) of computing power, with 23 speakers and 256-color ambient lighting, seat massage/heating/ventilation functions, etc. While bringing comfort and safety, it also increases the overall energy consumption of the vehicle.

In the settings of NIO models (Vehicle Settings > MyET5 > Trip Consumption), you can view the power consumption from separate categories including Driving, Driver Assistance, Cabin Comfort, Battery, and Other - five dimensions in all. Among them, assisted driving reflects the energy consumption of the intelligent assisted driving system, including hardware such as computing chips and perception hardware. The more hardware and computing power used and the longer the time it is activated, the higher the energy consumption. Battery thermal management ensures that the battery operates in the optimal temperature range, cooling/warming in real-time. ‘Other’ includes entertainment and comfort functions such as audio, seat adjustment, as well as interior and exterior lights, heated mirrors, electric suction doors, NOMI, and other convenience functions.

This overview shows that driving consumes the most power. The optimization of driving style has a far greater impact than Cabin Comfort and other factors, such as radio usage. Therefore, in real-world scenarios, users need not overly concern themselves with the utilization of their NIO vehicle’s convenience features.

Driving: This refers to the electricity consumed during the vehicle's operation to power the drivetrain. It depends on several factors, including the user's driving style, drive mode, usage scenarios, motor efficiency, and the vehicle's own resistance.

Driver Assistance: Refers to the power consumption of the intelligent assisted driving system. NIO's full range of models come standard with the highest specification intelligent perception hardware in the industry, which is automatically activated all-weather to create an exceptional assisted driving experience for users. It also lays a continuous and expandable foundation for the introduction of higher-level assisted driving functions in the future.

Cabin Comfort: Pertains to the electricity used for cabin temperature adjustment. NIO's entire lineup features heat pump air conditioning as standard, enabling rapid heating in winter. Through smart matching of heat pumps and PTC electric heaters, the system provides a warm and comfortable cabin environment in the most energy-efficient way during winter. NIO's automatic defogging algorithm includes an intelligent fogging risk assessment model that, upon accurately detecting fogging risk, activates windshield defogging to ensure safety while avoiding unnecessary energy consumption due to frequent activation.

Battery: Refers to the energy consumed in cooling or heating the battery in extreme temperatures to ensure it operates under optimal conditions. As one of the most critical systems in electric vehicles, the battery needs to function within a suitable temperature range since too low or too high temperatures can adversely affect its performance, lifespan, and safety.

Other: Covers the power consumption of low-voltage appliances inside the vehicle (12V), such as audio systems, seat adjustments, and other entertainment and comfort functions, as well as external and internal lighting, heated mirrors, electric suction doors, NOMI, and other convenience features.

In addition to its many features, the vehicle diligently monitors its status and certain components may awaken from standby mode. This can occur when you interact with the NIO App or when the Battery Health is assessed. As a result, you may observe a minor standby consumption, which could manifest as a slight decrease in the battery level over a period of days. This is a normal part of the vehicle’s advanced self-monitoring system, ensuring optimal performance and longevity.

How to Turn Electric Vehicles into Powerhouses of Endurance

ET5 not only inherits the high-performance and advanced smart technology features of NIO products, but also needs to optimize for maximum range performance while ensuring comfort and functionality. With the goal of "balancing exceptional driving experience with extended range", engineers from aerodynamics, chassis engineering, battery, motor, and electronic control systems, and control software teams work together in searching for solutions. We share four ways in which they try to achieve this:

1. Balancing aesthetics and functionality with low aerodynamic design

The 'drag coefficient,' often referred to simply as 'drag,' measures a vehicle's air resistance. For every 0.01 reduction in drag coefficient, the range of a pure electric vehicle can significantly increase by 5 to 8 km. According to the calculation formula: when external environmental factors are the same (vehicle speed, air density), a lower drag coefficient and smaller frontal area will reduce the air resistance during driving. For touring cars, due to functional considerations, it is not possible to excessively reduce the frontal area (which affects passenger and storage space). Therefore, optimizing the drag coefficient presents the primary opportunity for aerodynamic improvement.

Continuing the NIO family's design language, the ET5 includes various optimizations from millimeter-level design, guiding airflow smoothly and efficiently. The active air intake grille, front and rear spoilers, and ducktail aerodynamic kit balance sportiness and low aerodynamic drag, ultimately giving the ET5 a super-low drag coefficient of 0.24Cd while the ET5 Touring version also boasts a remarkably low drag coefficient of 0.25Cd.

2. Wheels that balance safety and range

To reduce drag and improve range, the ET5 is also offered with 19" Splendor Alloy Wheels. The design maximizes the coverage area of the spokes and improves the smoothness of the wheel surface while ensuring the opening area for heat dissipation, optimizing the drag coefficient by 1.3%.

Meanwhile, in order to reduce weight and decrease energy consumption, the ET5 wheel rims utilize a casting and spinning process. Compared to ordinary casting (gravity/counter-gravity casting), this method results in higher rim strength and lighter overall mass. Moreover, compared to forging, the production process is simplified, making it more suitable for large-scale production. Through spinning, the material structure of the rims becomes denser and fibrous, achieving lightweight while enhancing strength and toughness.

Lastly, paired with custom-made low rolling resistance tires for the ET5 from Michelin (Michelin E-PRIMACY series), utilizing low heat-generating rubber material with energy-saving belt structure design, it reduces tire deformation heat, lowers tire rolling resistance, and improves range. Additionally, the MaxTouch Construction? technology is employed to enhance the ground contact area, evenly distributing the significant stresses generated during rapid acceleration/braking and cornering, substantially increasing tire lifespan.

For those who opt for the exquisite Gladiator 20" rims, they will be rewarded with sportier tires that promise superior handling. This upgrade subtly shifts the focus from sheer efficiency to a blend of dynamic driving and striking exterior aesthetics, leading to a marginal rise in overall consumption. This is a choice for those who value performance and design, and are willing to embrace the thrill of sporty driving.

3. Balancing performance and range in the electric drive system

While accounting for over 80% of the vehicle's energy consumption, NIO's electric drive system aims to offer a high-performance experience that bridges racetrack excitement with road driving. Therefore, while equipped with dual motors as standard for enhanced performance and efficiency, the intelligent all-wheel-drive system and silicon carbide power module are optimized for extended range.

By combining fast-response, high-performance permanent magnet motors with endurance-focused, energy-efficient induction motors, the dual-motor intelligent all-wheel-drive system in the ET5 achieves a driving experience of "all-wheel-drive safety, two-wheel-drive energy consumption." This system, standard across NIO's lineup, operates with the permanent magnet synchronous motor in two-wheel-drive conditions, making energy consumption closer to that of single-motor models. In acceleration, traction, and other four-wheel-drive conditions, both motors work together, leveraging the advantages of dual-motor all-wheel-drive.

To enhance the driving experience, the engineering team also designed a "cross-controller vibration suppression system" for NIO's intelligent all-wheel-drive system. Based on the coordination between the vehicle control unit (VCU) and the motor control unit (PEU), the system adjusts motor torque output based on vehicle state prediction, optimizing the jitter generated when motor torque crosses zero, ensuring smoother engagement of all-wheel-drive.

The PEU (Power Electronic Unit) motor controller is the core controller for motor startup, forward/reverse, speed, and stop. Because it controls the current between the battery and the motor, good switching devices not only need to be more efficient and handle heavier loads but also need to minimize their own energy consumption. When used as a switching device, silicon carbide has lower losses, is more energy-efficient, operates at higher speeds, and has higher frequencies. Compared to traditional silicon-based modules, under the same power level, silicon carbide power modules have lower switching losses at high temperatures—when the chip temperature reaches 150℃, switching losses can be reduced by about 75%.

4. Balancing comfort and energy-efficient energy management

Accurate prediction and fine management can further improve the overall energy consumption performance of the vehicle. ET5 employs NIO's self-developed intelligent thermal management system, which can dynamically allocate energy for air conditioning, batteries, electric drive, and other multiple heat sources based on environmental conditions, user driving behavior, and current vehicle state, achieving efficient and environmentally friendly energy conservation.

For example, in high-temperature environments in summer, the risk of battery overheating affecting safety and lifespan is high, requiring the compressor to provide additional cooling to the battery. However, this will significantly increase compressor energy consumption. The system can learn from the driver's driving load, judge the risk of battery temperature rise, intelligently adjust the timing of active cooling to reduce the frequency of engagement, and reduce energy consumption. In cold environments, for example, under low-temperature high-speed driving conditions, heat recovery can save more than 10% of heat load energy consumption.

For energy-saving users/scenarios, the ECO energy-saving driving mode is designed to significantly reduce energy consumption while meeting basic driving needs: for example, the accelerator pedal curve will be gentler, braking energy recovery will be enhanced, the slope of the air conditioning temperature rise curve decreases, and the steady-state temperature control target will be as close as possible to the lower limit of human comfort, maximizing range.

How to improve range in daily driving

In the latest Banyan 2.3.0 release, our engineers have meticulously refined the range estimation algorithm. This enhancement now takes into account a wider array of user settings, including driving mode, air conditioning, and current driving conditions, to provide a more accurate assessment of energy consumption. This update offers a clearer understanding of how personalized settings can impact energy usage, leading to significantly more precise range predictions.

Moreover, users now have the option to display the newly improved estimation of remaining range permanently on the instrument cluster. To enable this feature, simply navigate to Vehicle Settings > Battery > Displayed Remaining Range > Estimated.

Please be aware that the route planning algorithm will always factor in your estimated range, based on your unique driving conditions, when calculating the expected battery level upon arrival. This ensures a more personalized and efficient driving experience.

Meanwhile, in daily use, we can also improve energy savings and range from the following aspects:

• Anticipate driving conditions to minimize unnecessary rapid acceleration and deceleration: NIO's full range is equipped with dual motors. When rapid acceleration occurs, the vehicle will automatically enable the four-wheel drive mode depending on the driving situation, and energy consumption is relatively high. Even with the energy recovery system, it is impossible to recover all excess kinetic energy during rapid braking. The best method is to estimate in advance and avoid waste caused by rapid acceleration/deceleration.

• Switch to suitable driving modes in a timely manner: For example, in congested traffic conditions, the sports mode not only cannot unleash performance but may also reduce passenger comfort due to aggressive acceleration. At this time, switching to comfort mode or even Eco mode can reduce energy consumption while maintaining comfort.
• Use NIO Pilot reasonably for highway driving: In highway conditions, NOP Pilot allows smoother and gentler operation, maintaining lower energy consumption for longer periods and improving range.
• Use air conditioning in AUTO mode: Although the multi-temperature zone function of the air conditioner can provide passengers with a personalized comfort experience, it will also further increase air conditioning energy consumption. Functions such as defrosting and defogging, while ensuring driving safety, will also increase energy consumption to a certain extent. They can be manually turned off when not in use or set to automatic mode.
• Use seat comfort functions reasonably: Compared to air conditioning, the heating/ventilation of seats provides a more efficient, direct, and lower energy consumption. In low-temperature environments, you can use seat heating/steering wheel heating to assist air conditioning heating, and in high-temperature environment, you can use seat ventilation to assist air conditioning cooling.

For electric vehicles, a sound and convenient energy replenishment system and continuous optimization of energy consumption are equally important.

From the outset, NIO wanted to create a power network offering the most convenient user experience. Our solution is NIO Power, featuring chargeable, swappable, and upgradeable batteries (upgradeable currently available in China and Norway) to provide users with power how they want it. Whether charging or swapping, each is a jigsaw piece that when put together provide a complete solution that works for everyone.

In Europe, as of May 29th, 2024, we have established 43 Power Swap Stations and 17 Power Charger Stations across the continent. Additionally, there are over 600,000 third-party chargers available for our users. All our stations operate from 7:00 to 22:00 and offer self-service operation. The swap penetration rate stands at 61.5%, with an impressive rate of one swap every six minutes during opening hours in 2024.

Regarding the range performance of electric vehicles, what other information are you interested in? Feel free to leave a comment in the comment section, and we will continue to invite engineers to share on topics that everyone cares about. For more knowledge, please continue to follow Tech Talk.