eVTOL, as the core carrier of low-altitude economy, has entered the stage of large-scale commercial use, and is expected to rapidly cultivate a complete low-altitude economic industry chain. China's development of eVTOL has comprehensive advantages and is expected to become a global business card. There are various technical routes for eVTOL, including rotor, power, and energy replenishment routes. As for rotor technology, tilt-rotor may become the mainstream route; for power technology, pure electric eVTOL may become the mainstream route; for energy replenishment methods, the battery swapping model may become a beneficial supplement to the eVTOL energy replenishment system. eVTOL's distributed electric drive system has high barriers to entry, focusing on core components and paying attention to the migration of new energy vehicles and the aviation industry chain
eVTOL Commercialization Accelerates, we refer to the research framework of the electric vehicle industry, and conduct a comprehensive analysis of the electric eVTOL industry ecosystem from the perspective of engineering disassembly. This report, as the opening of the eVTOL component series report, starts with discussions on eVTOL routes and distributed electric drive systems.
Abstract
China has comprehensive advantages in developing eVTOL and is expected to become a global business card. As a core component of low-altitude economy, eVTOL has seen intensive support policies from central and local governments, with qualifications for eVTOL represented by EHang Intelligent, Fēngfēi Technology, and XPeng Huitian recently accelerating.
We believe that, benefiting from the spillover advantages of the new energy vehicle industry chain, combined with national characteristics, policy support, etc., eVTOL is expected to become another global business card for the Chinese industry after new energy vehicles.
eVTOL technology routes are diverse, with three major routes of rotor, power, and energy supplementation.
The eVTOL industry is currently in its early stages of development, with multiple routes for rotor technology, power technology, and energy supplementation technology coexisting. Regarding the debate over eVTOL technology routes, based on industry development and product design logic, we analyze and explain through a comparison study with three questions and answers. We believe that, in terms of rotor technology routes, multi-rotor, compound wing, and tilt rotor will coexist in the short term, with tilt rotor potentially becoming the mainstream route; in terms of power technology routes, pure electric eVTOL may become the mainstream route; in terms of energy supplementation methods, battery swapping may become a beneficial supplement to the eVTOL energy supplementation system.
eVTOL Distributed Electric Drive System has high barriers, focusing on core components, and paying attention to the migration of new energy vehicles and aviation industry chains. This report, as the opening of the eVTOL component series report, first focuses on the highly redundant distributed electric drive system of eVTOL. Through the disassembly study of the eVTOL electric drive system, we discuss in detail the technical requirements, industry status, and future development trends of each core component such as motors, propellers, batteries, electronic controls, auxiliary power units, and thermal management.
We believe that the investment strategy for eVTOL electric drive systems, based on its unique high redundancy distributed system deployment logic, focuses on the manufacturing of core components and related materials, processes, and equipment supply chains, while closely monitoring relevant technological advancements; in terms of target selection, priority can be given to the scenario migration of existing new energy vehicle electric drive industry chain enterprises, as well as the dimensional expansion of enterprises with current aviation product supply qualifications.
Main Text
eVTOL: Clear Comprehensive Advantages, Expected to Redefine China's Industrial Image
With obvious development advantages, eVTOL is expected to add another global business card to the Chinese industry after electric vehicles
eVTOL (electric Vertical Take-off and Landing) refers to aircraft powered by electricity and capable of vertical take-off and landing. Compared to traditional aircraft, eVTOL has many advantages such as intelligence, safety, reliability, and environmental friendliness. Technological advancements and policy support have jointly catalyzed the rapid development of low-altitude transportation systems in various countries. Taking China as an example, the central and local governments have accelerated the introduction of support policies for "low-altitude economy," And issued the world's first eVTOL aircraft type certificate. We believe that eVTOL, as the core carrier of low-altitude economy, has entered the stage of large-scale commercial use, and is expected to rapidly cultivate a complete low-altitude economic industry chain.
China's advantages are obvious: national characteristics + policy support, overflow of new energy vehicle industry, diverse development
We believe that following the new energy electric vehicle industry becoming a global business card, China is expected to achieve similar success in the eVTOL industry. We believe that China's development of the eVTOL industry has the following advantages:
► Population and geographical characteristics: China has a dense population, heavy urban traffic pressure, and diverse and complex terrain, nurturing diverse scene demands; eVTOL, as a point-to-point spatial transportation mode, can break free from ground constraints, easily cope with complex scenarios, and effectively alleviate the pressure of infrastructure construction.
► Policy support: Both central and local governments attach great importance and have issued a series of industry support policies, and issued the world's first eVTOL aircraft type certificate. As a new type of transportation tool, similar to intelligent driving, policy support is a core necessary condition for industry development, and the Chinese government provides a fertile ground for its rapid development.
► Overflow of the new energy vehicle industry chain, reuse and manufacturing capabilities: eVTOL highly overlaps with the new energy vehicle industry chain, with many car companies such as XPeng, Geely, and GAC already making layouts. From power systems such as motors, batteries, to core components like LiDAR, IMU, and structural components like carbon fiber composites, China has relatively mature industrial advantages.
► Diverse development, competition among many: China has many eVTOL research and production companies such as EHang Intelligence, Fēngfēi Aviation, Shíde Technology, Wōfēi Longkong, and XPeng Huitian, including both start-up technology companies focusing on a niche market and car companies expanding into the sky. We expect that in the future, there may be technology giants extending their layout. The rich ecosystem of participants helps catalyze the rapid growth of the industry.
Rich industry ecosystem, focusing on the eVTOL production system
We believe that the eVTOL ecosystem mainly includes the following roles: policy authorities, eVTOL production companies, command and dispatch centers, airport construction, and end-user groups.
► Policy authorities: Including the Civil Aviation Administration, Ministry of Industry and Information Technology, local governments, etc., issuing policies and industry standards for eVTOL production, manufacturing, and commercial operation, such as the issuance of TC, AC, and PC certificates for eVTOL.
► eVTOL production system: Including main manufacturers and upstream component suppliers such as propulsion, flight control, communication, navigation systems, etc. Currently, there are no industry standards for domestic eVTOL, and the approval is based on a "case-by-case" system, with unclear component qualifications, still under improvement.
► Command and dispatch centers: Responsible for flight management, route planning, traffic control, emergency response, and data management, for example, Shenzhen has established a dedicated low-altitude service company within the system, responsible for daily operations and coordination with the aviation system. As it involves three-dimensional maps, airspace management, etc., it is mainly supervised by government agencies, and the construction of the dispatch system is jointly completed by the Civil Aviation Administration's air traffic control and internal and external software development companies ► Airport Construction: eVTOL, unlike conventional aircraft, does not require a runway and can take off and land only on a helipad, reducing the standards and difficulties of airport construction. Due to its small space requirement, it allows for flexible layout, drawing reference from the helicopter helipad construction system.
► End-user Demand Groups: Involving passenger transportation, logistics, emergency rescue, tourism, industrial monitoring, and other terminal scenarios, currently extending rapidly from commercial B-side and government G-side to consumer C-side groups.
We believe that the production system is the core, policies are the premise, command and dispatch centers, airport construction, etc., are safeguards, and end-user demand groups are the objectives, collectively promoting the technological advancement of the eVTOL production system, the maturity of the industry chain, and the acceleration of commercialization.
Chart 1: eVTOL Industry Ecosystem Chart
Source: EHang Intelligent Official Website, CICC Research Department
eVTOL Core Route Three Questions and Three Answers: Rotor Route, Power Route, Energy Supplement Route
In the early stage of eVTOL industry development, facing rotor technology routes, power technology routes, and energy supplement routes, multiple choices are currently coexisting in the industry. Based on industry development and product design logic, we believe that: in terms of rotor technology routes, tilt-rotor may become the mainstream route; in terms of power technology routes, pure electric eVTOL may become the mainstream route; in terms of energy supplement methods, battery swapping mode or jointly building a rapid energy supplement system with charging mode for eVTOL.
eVTOL Rotor Technology Route: Tilt-rotor may become the future mainstream
The classification of eVTOL rotor technology solutions is complex. Based on the real products of many eVTOL companies at home and abroad, we simply divide them into three categories: multi-rotor, compound wing, and tilt-rotor.
► Multi-Rotor: With multiple horizontal rotors, simple structure, high flexibility, but high energy consumption during cruising, with disadvantages such as short range, low efficiency, and low payload. Representative models include EHang 216, XPeng Huitian X2, etc.
► Compound Wing: Combining horizontal rotors responsible for takeoff and landing with vertical rotor systems for cruising, combining the characteristics of multi-rotor and fixed-wing, high efficiency, long range, but with complex aircraft structure and flight control. Representative models include Peak Fly "Shengshilong", EHang EH-VT30, Volocopter's VoloConnect, etc.
► Tilt-Rotor: The same set of rotors can switch between vertical takeoff and horizontal cruising modes through mechanical mechanisms, including tilt-ducted models. All power is available in real-time with this solution, with advantages of low aircraft weight, high energy efficiency, significant endurance, and payload advantages, but requiring high comprehensive capabilities in mechanical structure design and flight control systems. Representative models include JOBY S4, Times E20, etc Chart 2: Three representative rotorcraft models
Source: JOBY Official Website, CICC Research Department
Tilt-rotor eVTOL is the trend of industrial development, with Chinese companies accelerating to catch up from multi-rotor and compound-wing solutions. In terms of technical difficulty, system efficiency, and endurance, multi-rotor, compound-wing, and tilt-rotor increase in that order. Currently, leading global companies such as JOBY and Archer have adopted tilt-rotor technology solutions, while domestic companies like EHang and Volocopter have also made attempts. Based on the recent airworthiness certificates issued by the Chinese government, EHang 216 and Volocopter V2000CG belong to the multi-rotor and compound-wing models respectively. We believe that the technical level of domestic tilt-rotor solutions may still lag behind foreign counterparts. Combining industry reality and development trends, referencing the concept of biological vertical ecological systems, we expect that the three technical solutions are likely to coexist in the long term based on scenario stratification, with compound-wing and tilt-rotor becoming the mainstream route for Chinese eVTOL.
eVTOL Power Technology Route: Pure electric or hybrid dominance
eVTOL, as the name suggests, uses electricity as the power source, divided into pure electric and hybrid power.
► Pure electric eVTOL: With features like zero emissions and low noise, but limited by the energy density of current battery technology, its range and payload capacity are relatively limited. The power system adopts a distributed system with multiple motors and multiple batteries.
► Hybrid power eVTOL: Combining batteries with another energy source, such as hydrogen fuel or fuel, it has advantages in range and payload. The power system usually includes one or more motors, as well as an auxiliary fuel engine or fuel cell system.
Chart 3: All-electric eVTOL distributed architecture
Source: Drone Net, CICC Research Department
Chart 4: XPeng Heitech X2's distributed battery system
 transport. For example, for the EHang 216 model, the single flight endurance time is about 25 minutes, and we estimate that its safe charging time may exceed 10 minutes. Embedding relevant parameters into short-haul passenger transport scenarios, after short-haul tourists land, they need to wait for a long time for charging before they can carry the second wave of tourists for takeoff. There is room for optimization in the eVTOL commercial operation model.
Drone battery swapping has matured and been commercially promoted, and eVTOL battery swapping has seen models in operation. Currently, the drone field's battery swapping mode has been commercially mass-produced and deployed for automatic recharging for logistics and inspection scenarios, with representative companies including Meituan, DJI, Hanchuan Intelligent, StarLogic Intelligent, and Israel's Airbotics. Taking Hanchuan Intelligent as an example, its drone intelligent mobile inspection system can support the operation management and automatic recharging of multiple DJI M300 drones The representative enterprise for eVTOL battery swapping is Volocopter, and its first commercial aircraft VoloCity has 9 sets of batteries. All batteries can be quickly replaced within 5 minutes, enabling short-distance air transportation of 30km within the city.
We believe that battery swapping has the potential to become an important supplementary energy replenishment method for eVTOL in addition to charging, with the following advantages:
► Enhancing production efficiency and profitability: eVTOL is a production tool, and battery swapping can effectively improve operational efficiency and economics, allowing for easy achievement of "3-minute battery swapping for 1-hour flight", thereby increasing operational revenue.
► High battery standards for aviation, professional maintenance and regulatory risk prevention: eVTOL batteries are deployed in a distributed manner, with single machines like EHang, JOBY equipped with 4 battery packs, and others like EHang 216, Lilium Jet with up to 10; aviation battery safety is more critical than automotive safety, managing multiple batteries poses greater challenges, while within battery swapping stations, each battery can be professionally managed and monitored, effectively avoiding problematic batteries in flight.
► System compatibility, low infrastructure costs: Fixed routes, point-to-point mode, the design and infrastructure construction costs of battery swapping systems are low, and can also achieve more flexible energy replenishment by combining with mobile battery swapping vehicles based on destination changes.
Figure 5: Airbotics' drone battery swapping station and interior view
Source: Airbotics official website, CICC Research Department
We believe that battery swapping mode will jointly build a rapid energy replenishment system for eVTOL along with fast charging mode. With the stabilization of eVTOL commercialization, aircraft design, and power parameters, the advantages of fixed routes and model-specific battery swapping modes will become more prominent.
In conclusion, we believe that eVTOL is poised to benefit from the spillover effects of China's new energy vehicle industry chain. With strong policy support, it may become another global business card for China's industry after new energy vehicles.
Based on our discussion of eVTOL's rotor technology route and power technology route in Chapter 1, we will focus on the engineering analysis of eVTOL's electric drive system in the subsequent sections. Using pure electric eVTOL as an example, we will conduct a comprehensive analysis of the industry ecosystem of eVTOL following an engineering breakdown approach, referencing the research framework of the electric vehicle industry. This report will first focus on the engineering analysis of eVTOL's electric drive system.
Figure 6: Panoramic view of the pure electric eVTOL system, composition of the electric drive subsystem
, and the tilt-rotor representative model JOBY S4 carries 6 sets of electric drives. However, whether it is a multi-rotor, compound wing, or tilt-rotor eVTOL, specific to each rotor, the structure of the drive system is generally the same (tilt-rotor needs to add a mechanical switching device). Referring to the research framework of electric vehicle drive systems, we divide the eVTOL electric drive system into subsystems such as motor, propeller, battery, electronic control and auxiliary power, thermal management, etc.
Chart 7: The electric drive system of eVTOL is derived from the electric drive system of electric vehicles, and the industrial chain has transferability
Source: Tesla Official Website, Joby Official Website, Zhongjin Company Research Department
Motor: Direct drive motors may become mainstream, high power density is the technological direction
The eVTOL motor is used to provide power to the propeller, with one motor per propeller. The system requires high power, high torque, low noise, and corresponding motor parameter requirements to meet high torque-to-weight ratio, high power-to-weight ratio, etc. The existing drive modes of eVTOL motors are divided into two types:
► Direct drive motor: The motor directly drives the propeller, with a simple structure, but requiring a high torque low-speed motor, which poses technical challenges.
► Combined drive: Referring to automotive electric drives, it uses a motor + planetary gear reducer, which can use existing high-speed motors, with mature technology, but a complex structure, and high maintenance requirements for internal gears, bearings, etc. in the gearbox.
Chart 8: Joby S4's latest integrated direct drive motor
Source: Joby Official Website, Zhongjin Company Research Department With the advancement of technology, direct drive motors may become mainstream. Currently, there are two motor solutions in the market, but there is limited disclosure of related company information. Due to technological limitations, some companies adopt a combination drive scheme, achieving high power output through the combination of high-speed motors and large reduction ratio gearboxes. Existing direct drive motor solutions are mainly seen in multi-rotor light eVTOLs such as EHang X2, with lower single motor power density requirements, making it relatively easier to achieve. We believe that, based on first principles, considering reducing weight to improve efficiency, along with the advancement of high-power motor technology, direct drive motors may become the mainstream driving method for eVTOL motors.
Propellers: "Wheels in the Sky", high barriers to entry for carbon fiber materials and manufacturing processes, focusing on new technological solutions
Propellers are key components of eVTOL electric drive systems, with high requirements for materials, processes, etc. Propellers are responsible for converting power from the motor into lift or thrust, enabling eVTOL to achieve vertical take-off and landing, cruising, and other flight states. Propellers need to meet multiple requirements such as high aerodynamic efficiency, structural strength, noise control, reliability, and minimizing energy consumption. Analogous to the drive system of new energy vehicles, eVTOL propellers are similar to the "wheels" of a car, but because the propeller's working medium is air, there are higher requirements for materials, shaping processes, reliability, etc.
Carbon fiber propellers have become mainstream, with high manufacturing process and equipment thresholds. Propeller materials and blade design are highly related to system efficiency. Blade materials are usually lightweight and high-strength composite materials, such as carbon fiber or fiberglass-reinforced plastics. Most existing eVTOL propellers are made of carbon fiber composite materials, such as XPeng EHang X2. The manufacturing process and equipment requirements for carbon fiber propellers are high, and carbon fiber is the main material for large and medium-sized components of eVTOLs such as the fuselage, wings, and seats.
Figure 9: XPeng EHang's carbon fiber propeller blades, carbon fiber fuselage
Data source: XPeng EHang official website, CICC Research Department
Batteries: Highly redundant "distributed heart", high energy density is the technological direction
eVTOLs use a distributed deployment of multiple batteries to ensure system high redundancy and safety. The electric drive system of eVTOL adopts a distributed deployment, mainly considering the aircraft's stringent requirements for high system redundancy. In terms of specific models, Joby S4 has 6 sets of tilt rotor drive systems, with the entire aircraft equipped with 4 sets of distributed battery packs. Each motor is connected to two sets of battery packs, one primary and one backup, and each battery pack is connected to multiple motors to ensure that the entire system can operate safely with high redundancy in the event of sudden failure of any motor or battery pack in the air. XPeng EHang X2 is equipped with 4 sets of distributed battery packs, EHang 216 with 10 sets of distributed battery packs, and Lilium's multi-channel tilt rotor model Jet also has 10 sets of battery packs Chart 10: Joby S4 Distributed with 4 Battery Packs
Source: Joby official website, CICC Research Department
Increasing battery energy density is a core requirement and technological development direction. eVTOL has high requirements for battery energy density, battery pack size, etc. Taking Joby S4 as an example, its battery energy density is 288Wh/kg, and the battery pack uses carbon fiber composite materials to reduce weight. In addition, the distributed battery deployment scheme also places higher demands on the comprehensive management of multiple battery BMS. We believe that currently, eVTOL OEMs mainly focus on self-developed battery BMS systems because of the high coupling with the flight control system. The external demand is mainly for high energy density battery cells, with a majority currently using high-nickel ternary lithium batteries. Contemporary Amperex Technology Co., Limited (CATL) released solid-state batteries in 2Q23, with a single cell energy density of up to 500Wh/kg, meeting aviation-grade standards and testing, satisfying aviation-grade safety and quality requirements.
Electric Control and Power Electronics: Increased complexity in distribution architecture, elevated requirements for component processes, materials, and integration
The components and system requirements of eVTOL distribution architecture are increasing. Similar to electric vehicles, eVTOL's electric drive system also requires motor control, high-low voltage conversion DC-DC, and power distribution unit (PDU) for power electronics. Given the characteristics of high-power electric motors in eVTOL, higher requirements are placed on control modules such as switch frequency, system insulation and thermal limits, NVH optimization, harmonic suppression, involving silicon carbide (SiC) devices, precision encapsulation, high-voltage architecture, high heat flux density cooling, high integration sensors, and requiring a class of aviation system design with high reliability.
Chart 11: Schematic Diagram of eVTOL Distribution Architecture
Source: Xinyi Technology official website, CICC Research Department
Both outsourcing and self-development coexist for core components, and component configuration follows system redundancy requirements. Currently, SiC devices are widely used, and high-voltage solutions vary depending on aircraft design. At the component level, motor controllers and motors need to be co-designed. Some eVTOL OEMs choose to outsource the entire motor control system, while others opt for self-development due to the coupling between power electronics and flight control systems Similar to the battery BMS system. For Xiaosan Electric, take the charging eVTOL as an example. The model equipped with OBC generally only carries one due to its use on the ground scene, while DC-DC and PDU are configured differently according to the system design. Due to redundancy considerations, they generally start with dual backups.
Thermal Management: The core guarantee of the drive system, liquid cooling solutions or accompanying industry development become mainstream
Thermal management of eVTOL electric drive is the core guarantee of the system. The thermal management of eVTOL drive system mainly involves the motor, motor controller, battery, and Xiaosan Electric, which is highly similar to the thermal management system of electric vehicles. The difference lies in the larger windward area and windward angle of eVTOL, and the characteristics of distributed electric drive systems make the thermal management of eVTOL drive systems more challenging. We believe that currently, for the thermal management of motor controllers, lightweight eVTOL mainly relies on propeller flow field cooling, while medium and large eVTOL motors generally use liquid cooling to improve efficiency; for battery system thermal management, similar to motor thermal management, both air cooling and liquid cooling are used.
Chart 12: Xiaopeng Huitian peak power 50kW wind-cooled direct drive motor
Source: Xiaopeng Huitian official website, CICC Research Department
Precision Embedding: The core process of upgrading electronic and electrical architecture
Integrated precision embedding is expected to become the core process of upgrading eVTOL electronic and electrical architecture. eVTOL has high requirements for its own weight, spatial layout, and architecture design. The design of electronic and electrical architecture needs to meet the requirements of distributed redundancy, save space as much as possible, avoid excessive discrete components and complex wiring; in addition, considering the vibration of the eVTOL body during aerial flight, the reliability of assembly-type components will be affected, such as loosening of nuts and bolts.
Referring to the technical development of electric vehicle electronic and electrical architecture, the "integrated precision embedding" process has begun to penetrate rapidly under the leadership of BMW, Tesla, and others. This process can highly integrate numerous discrete components, multiple wire harnesses, connectors, etc., into an independent component, which can save materials, space, and weight, and improve system safety and reliability, in line with the trend of intelligent and high-voltage technology.
Chart 13: Some products of Xingrui Technology, and product images of Tesla using this process
Source: Xingrui Technology official website, Drive Vision official website, Zhongjin Company Research Department
Authors: Deng Xue, Yuan Mu, Chang Jing, Source: Zhongjin Company, Original title: "eVTOL: Discussion on Technology Roadmap, Detailed Explanation of Distributed Electric Drive"
Analyst Deng Xue SAC License Number: S0080521010008 SFC CE Ref: BJV008
Analyst Yuan Mu SAC License Number: S0080523110002
Analyst Chang Jing SAC License Number: S0080518110003 SFC CE Ref: BMX565