On March 27, the Ministry of Industry and Information Technology, together with the three ministries and commissions, issued the "Implementation Plan for the Innovative Application of General Aviation Equipment (2024-2030)" [1], proposing to "promote the mass production of 400Wh/kg aviation lithium battery products and realize the application verification of 500Wh/kg aviation lithium battery products." For infrastructure, it is proposed to "improve functional services such as navigation and positioning, communication, meteorology, and charging." ”
summary
Batteries: eVTOLs require batteries with high safety, high energy density, and high power density, and solid/semi-solid-state batteries may be the mainstream route in the future. Among them, high safety means that the battery system needs to achieve aviation-grade safety, while energy density and power density directly determine the performance indicators such as eVTOL load and cruising range. The existing battery technology level fails to perfectly meet the requirements of eVTOL for battery energy density and power density, and the mainstream technology routes under research include lithium batteries and hydrogen fuel cells.
► Lithium battery: Lithium battery is a battery with leading commercialization progress, we estimate that mainstream eVTOLs such as Joby S4 and Fengfei Shengshilong use liquid and semi-solid lithium battery solutions, but the ideal requirements for eVTOL for battery pack energy density and peak power density are 400-500Wh/kg and 1.5-2.0kW/kg respectively. Semi-solid lithium batteries are used to improve the upper limit of energy density and safety to adapt to eVTOL application scenarios.
► Hydrogen fuel cell: Hydrogen fuel cell has high energy density, fast charging speed and good low temperature performance, and the energy density can reach 600Wh/kg-1000Wh/kg, but the power density can only reach 600W/kg, which is far lower than the peak power density requirements of eVTOL.
Energy replenishment: Charging may be the mainstream solution in the future. Charging is currently the mainstream energy supplement solution chosen by OEMs, its core advantage is low initial investment and follow-up operating costs, the disadvantage is that the charging speed is slow, we believe that the subsequent charging power increase is expected to further save charging time, considering the cost and benefits, charging or will become the mainstream energy supplement solution for eVTOL in the future, at present, Joby, Beta and other eVTOL charging solutions. Compared with charging, the speed of battery swapping and replenishment is faster, but the cost of investment, construction and operation and maintenance is higher.
risk
The implementation of policies is less than expected, and the industrialization process is less than expected.
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What kind of battery is needed for eVTOL?
Power batteries are a key breakthrough point in the development of eVTOL, and the technical level needs to be improved urgently
The electric drive system of eVTOL is mostly distributed to meet the strict requirements of high redundancy and high safety of aircraft. This distributed powertrain architecture consists primarily of a high-voltage battery, a low-voltage battery, a flight control computer (FCC), an electronic governor (ESC), component cooling systems, cables, tubing, motors, and rotors/propellers. The powertrain is mainly divided into two functional modules, 1) the energy storage module is composed of a high-voltage battery and a low-voltage battery, which undertakes the function of energy storage, and 2) the energy conversion module is composed of an ESC and a motor, which is responsible for converting the energy in the energy storage module into mechanical energy. In addition, each motor and each ESC corresponds to a cooling system that works independently, and all high-voltage batteries share a liquid cooling system.
Chart: Typical eVTOL powertrain architecture
Source: "Composite Wing eVTOL Battery Demand and Impact on Powertrain Safety" (Ding Shuiting, 2024), CICC Research
Power batteries are an important part of the realization of electric flight, and their technical level and safety level are particularly important for the commercialization of eVTOL. For the all-electric propulsion power system, the battery is the core component of the power system, which bears the responsibility of providing stable energy for the power output components such as the electric motor and ensuring the flight demand, and the performance of the power battery directly affects the key indicators such as the cruising range, flight speed, and load capacity of the eVTOL. Under the current state of technology, insufficient energy density and low discharge rate of batteries are one of the core bottlenecks hindering the industrialization of eVTOL. At the same time, the power battery accounts for a large proportion of the value of the whole machine, and the current price of multi-rotor eVTOL (such as eight-rotor, six-rotor, etc.) is between 5 million and 8 million, and the value of motors, batteries, and avionics accounts for as much as 70%, and the cost of batteries accounts for about 20% of the overall cost.
eVTOLs require fast-charging batteries with high safety, high energy density, and high power density
eVTOLs need to be equipped with fast-charging batteries with high safety, high energy density, and long life. The battery is the core component of the power system, and its indicators directly determine the safety and flight performance of eVTOL. The eVTOL battery needs to supply energy to the motor stably, ensure that the eVTOL can have a large energy margin in the event of an emergency, and avoid the potential safety hazards caused by rapid charging and discharging to accelerate the degradation of battery life, so as to maximize the battery life. We believe that the unique operation profile and task cycle of eVTOL and the harsh operating environment have put forward higher requirements for the battery system, and the eVTOL battery has more stringent requirements in terms of performance and safety than the on-board battery, and it is necessary to comprehensively improve the energy density, power density, safety, charging rate, cycle life and other indicators of the battery system.
► Safety: eVTOL is an aviation aircraft, requiring aviation-grade safety, and its safety requirements are far greater than that of new energy vehicles, the US FAA Part 23 certification requires the probability of an accident to be controlled at 1 in 10 million, while the EU EASA requires the probability to be controlled in 1 billion. Batteries require safer materials and structural systems, as well as higher consistency and reliability.
► Energy density: Due to the need for take-off, eVTOLs need batteries with high energy density to reduce their own load, provide longer endurance and more passenger space. At present, commercial lithium-ion batteries have an energy density of 250Wh/kg, and a 100kWh battery pack is required for a range of 200-300km. The power required for eVTOL vertical take-off is 10-15 times that of ground driving, and the commercial threshold is as high as 400Wh/kg, which is much higher than the energy density of current automotive power batteries.
► Power density: Due to the particularity of take-off and landing scenarios, the instantaneous charge and discharge rate of the battery is higher than that of the traditional battery. According to the research of William L. Fredericks et al. in 2018, there is a significant difference between the discharge power requirements of eVTOL and electric vehicles, with a discharge rate of 4C during take-off and a maximum of 5C during descent (the voltage decreases when descending, and a higher current support power needs to be output), while the discharge rate is about 1C during cruising. In addition, in order to cope with situations such as smooth and safe landing or forced landing when the battery is low, the power requirements of the eVTOL battery are higher.
► Fast charging performance: The fast charging ratio of eVTOL reaches 5C, which can increase the daily frequency of aircraft use and improve the investment economy of air taxis, and the fast charging performance of batteries is very important to promote the commercialization process of eVTOL.
► Cycle life: Increasing battery cycle life can reduce battery replacement costs, increase the profitability of eVTOLs throughout their life cycle, and also contribute to the commercialization process.
The requirements for eVTOL battery certification are stringent, and standardized testing and installation standards are constantly improving. The 2015 FAA AC 20-184 Circular integrates standards RTCA DO-311 and RTCA DO-160G, among others, to provide manufacturers and installers with instructions on acceptable compliance methods to meet the installation, operation, maintenance, and airworthiness requirements for the installation of lithium batteries and battery systems on aircraft. In 2017, RTCA DO-311A perfected the aerospace lithium-ion battery testing standard. In 2020, the European Aviation Safety Agency (EASA) issued special conditions SC E-19, which clarified the requirements for the validation of power units for vertical take-off and landing aircraft. In January 2024, the Aircraft Airworthiness Certification Department of the Civil Aviation Administration of China also referred to RTCA DO-311A to form the "Rechargeable Lithium Battery and Battery System" (CTSO-C179b). We believe that these regulations will provide guidance information for eVTOL battery standards, which will facilitate more comprehensive supervision and promote the improvement of battery technology.
Chart: eVTOL battery testing and certification standards
Source: FAA, EASA, Civil Aviation Administration of China, CICC Research
What are the current technical solutions and application cases of eVTOL?
Lithium battery: Focus on the research and development of high-energy-density solid-state routes, and the existing cases may mainly use liquid lithium-ion batteries
Low energy density is the core technical difficulty of lithium batteries, and solid-state batteries may be the way to break the game. Lithium batteries are high-energy-density batteries with leading commercialization progress, and are widely used in downstream fields such as new energy vehicles, energy storage, two-wheeled vehicles, consumer electronics, and tool batteries, and the technology is relatively mature. However, at present, the lithium batteries with mature technology and high degree of commercialization are mainly liquid lithium-ion batteries, and their upper limit of energy density at the battery pack level is 250-300Wh/kg, which can meet the use needs of eVTOLs with a small number of passengers and short mileage, but it is still difficult to meet the ideal requirements of eVTOL for the energy density of battery packs of 400-500Wh/kg. In order to break the upper limit of the theoretical energy density of lithium batteries and meet the requirements of eVTOL energy density, the current market mainly improves the upper limit of energy density from battery material innovation, in which the negative electrode is mainly made of lithium metal with high energy density, and the electrolyte is mixed from electrolyte to solid-liquid and solid-liquid and the evolution of solid electrolyte.
► Lithium metal anode: high theoretical capacity, low mass production cost, lithium dendrites have not been completely solved. The commercial graphite anode has a capacity of about 360mAh/g, which is very close to its theoretical specific capacity of 372mAh/g, while the theoretical capacity of the lithium metal anode is as high as 3860mAh/g, far exceeding the graphite anode. As a result, lithium metal batteries can achieve an energy density of more than 350Wh/kg, which is significantly higher than the current mainstream lithium-ion mass/volume energy density, and due to the simplification of the lithium metal anode process and better recovery effect, SES believes that the mass production cost of lithium metal batteries may be lower than that of lithium-ion batteries in the long run. However, compared with the traditional graphite anode, the lithium metal anode has high activity and high volume change rate, which leads to the instability of the interface between the anode and the electrolyte, and is prone to composition and structure fluctuations, SEI (Solid Electrolyte Interphase) fracture or even collapse, which in turn leads to problems such as lithium dendrites, shortens the battery life, and affects the fast charging performance and safety of the battery.
► Solid-state electrolyte: adapt to the positive and negative electrodes with high energy density to improve the energy density of the battery. The solid-state electrolyte replaces the electrolyte and separator, which can ensure a more stable match between the electrolyte and the high-energy electrode during battery operation, and avoid factors that threaten the safety of the battery such as electrode decomposition, oxygen evolution, and dendrite growth. Its advantages are 1) the solid electrolyte is non-flammable and safer, 2) it has a wider electrochemical window, it is easier to carry high-voltage cathode materials, and the negative electrode can also be effectively compatible with lithium metal anode, thereby improving the energy density of the battery, and 3) it has a higher mechanical modulus, which can effectively inhibit the growth of dendrite and improve the rate performance. Due to the relatively high difficulty of using all-solid-state electrolyte technology, and the limited industrialization support and high cost, most battery factories currently mainly launch semi-solid-state batteries using solid-liquid hybrid electrolytes, such as CATL's condensed matter batteries, which have a single energy density of up to 500Wh/kg, and all-solid-state batteries are still in the R&D and incubation stage.
Due to the many side reactions between the lithium metal anode and the liquid electrolyte, and the solid-state electrolyte can be more effectively compatible with the lithium metal anode, the main direction of eVTOL battery research and development is solid-state/semi-solid-state battery. There are many technical routes for solid-state batteries, if they are divided into Li-LMO (lithium metal anode-lithium metal oxide cathode), Li-S (lithium metal anode-sulfur cathode) and Li-Air (lithium metal anode-oxygen cathode) according to the positive and negative electrodes, the theoretical energy density of these three types can basically meet the requirements of eVTOL for the energy density of the battery system.
In addition to energy density, solid-state batteries still need to solve the problem of power density. For eVTOL, the energy density and power density of the battery directly determine its performance indicators such as load and range. The theoretical energy density of solid-state battery technology can meet the energy density requirements of eVTOL batteries, but solid-state batteries use solid-state electrolytes, which will produce greater internal resistance and contact impedance, resulting in lower power density of solid-state batteries than liquid lithium-ion batteries, so improving power density is also another core problem that solid-state battery technology needs to solve.
Chart: Comparison of mass-energy density of lithium-ion batteries and three types of solid-state lithium batteries
资料来源：Reviving the lithium metal anode for high-energy batteries（Cui，2017），中金公司研究部
Chart: Comparison of volumetric energy density of lithium-ion batteries and three types of solid-state lithium batteries
资料来源：Reviving the lithium metal anode for high-energy batteries（Cui，2017），中金公司研究部
Case Study: Existing eVTOL batteries are still dominated by liquid and semi-solid solutions. Solid-state batteries are still in the research and development stage, and combined with the parameters of each battery, we estimate that liquid lithium-ion batteries and semi-solid-state batteries are currently the mainstream battery solutions for eVTOLs. According to the research of Shashank Sripad et al. on the performance of eVTOL batteries, combined with the battery data of mainstream eVTOL machine factories, we believe that the energy density of the current relatively cutting-edge battery technology that has achieved mass production can basically meet the requirements of eVTOL 5-seat +250 km range, but from the perspective of power density, the power density of the battery is higher when eVTOL lands, reaching 1.5-2.0kW/ kg, the cutting-edge battery technology that has been mass-produced at present is basically difficult to take into account the requirements of eVTOL for energy density and peak power density during landing.
Chart: Current eVTOL battery solutions at a glance (as of April 6, 2024)
Source: Company's official website, CICC Research Department
Chart: Comparison of the current energy density and power density of eVTOL battery packs with the development of lithium battery technology
Note: "Current Li-ion" refers to battery technology that has been mass-produced, "Novel/prototype Li-ion" refers to battery technology that has recently been developed or used for high-performance applications, and "Advanced" Represents a new battery technology that has not yet been commercialized, the abscissa is the energy density, which mainly represents the range requirement, the horizontal error bar parallel to the abscissa represents the estimated value when the empty weight (equal to the maximum take-off weight minus the payload and battery weight) in the proportion of the total aircraft weight is 0.45-0.55, the ordinate is the power density, which mainly represents the take-off and landing demand, and the error bar parallel to the ordinate shows the power requirement at landing
资料来源：《The promise of energy-efficient battery-powered urban aircraft》（Shashank Sripad，2021），中金公司研究部
Hydrogen fuel cell: It is still in the early stage of commercialization, and the hydrogen-lithium hybrid system may be in transition
Hydrogen fuel cell is a power generation device that directly converts the chemical energy of hydrogen and oxygen into electrical energy, which is composed of a cathode (oxygen), an anode (hydrogen) and an electrolyte membrane. According to the different electrolytes, hydrogen fuel cells are roughly divided into proton exchange membrane fuel cells (PEMFC), alkaline fuel cells (AFC), phosphate fuel cells (PAFC), solid oxide fuel cells (SOFC), and the most suitable hydrogen fuel cell technology for aircraft is the low-temperature proton exchange membrane (LT-PEM) fuel cell, which can not only increase the energy storage, but also help the system achieve load tracking and peak adjustment to optimize the volume of the hydrogen fuel cell.
Figure: Structure of a proton membrane fuel cell cell
Source: Key Science and Technology for Hydrogen Energy and Fuel Cells: Challenges and Prospects (Mingyuan Zhu, 2021), CICC Research
Chart: Hydrogen fuel cell electric fan engine
Source: Century Energy Network, CICC Research Department
Chart: Hydrogen fuel cell classification and performance comparison
Source: Key Materials and Technologies for Proton Exchange Membrane Fuel Cells (Jianguo Liu, 2021), Research Department, CICC
Compared with lithium batteries, hydrogen fuel cells have high energy density, fast charging speed, good low-temperature performance, and great application potential. Compared with lithium batteries, the energy density of hydrogen fuel cells is much higher than that of lithium-ion batteries, which can reach 600Wh/kg-1000Wh/kg, and its theoretical upper limit is 10,000-20,000Wh/kg. At the same time, unlike lithium batteries that cannot be charged below -20°C and the range loss may reach 30%, hydrogen fuel cells have good low-temperature performance, which can still self-start at -30°C and can still be stored at -40°C. In addition, hydrogen fuel cells also have the advantages of high conversion efficiency, large capacity, wide power range, and short hydrogen exchange time. In the long run, the high energy density of hydrogen fuel cells meets the development needs of eVTOL and has broad application prospects.
Policies support the development of hydrogen aviation, and the commercialization of hydrogen aviation is accelerating. In recent years, the field of hydrogen aviation in mainland China is accelerating with the support of policies. Since 2021, China has successively issued policies such as the 14th Five-Year Plan for the Development of Civil Aviation[2], the Medium and Long-Term Plan for the Development of the Hydrogen Energy Industry (2021-2035)[3], and the Guidelines for the Construction of the Standard System for the Hydrogen Energy Industry (2023 Edition)[4], actively exploring the application of fuel cell aircraft and other fields, and promoting the research and development of large-scale hydrogen energy aircraft. In October 2023, the four departments jointly issued the "Green Aviation Manufacturing Industry Development Outline (2023-2035)" [5], proposing the development goal of "completing the pilot operation of electric vertical take-off and landing aircraft (eVTOL) and completing the feasibility verification of key technologies of hydrogen energy aircraft by 2025", and emphasizing the need to "actively lay out new tracks such as hydrogen aviation". In addition, various localities are also actively exploring the demonstration application of hydrogen energy and fuel cells in the aviation field, and Guangzhou has proposed that by 2030, more than 100,000 sets of fuel cell systems will be installed in automobiles, ships, aviation and other fields [6]. With the support of policies, we believe that the research and development of key technologies for hydrogen aviation is expected to be further accelerated, and the technology application mode of collaborative innovation with the upstream and downstream of hydrogen energy will be opened up, and the industrialization progress will be accelerated.
In the short term, hydrogen fuel cells are insufficient in power density, and hydrogen-lithium hybrid systems are expected to accelerate. Although hydrogen fuel cells have significant advantages in energy density, charging speed, low temperature performance and other performance, the current power density of hydrogen fuel cell systems can only reach 600W/kg, which is still far from the power density of 1.0-1.5kW/kg usually required by aircraft, and it is difficult to meet the power required for eVTOL take-off and landing. Given that the power density of hydrogen fuel cells is difficult to increase rapidly, and lithium-ion batteries have a high power density and can release energy during high-power demand stages such as take-off, landing, and hovering, we expect that the hydrogen-lithium hybrid system is expected to accelerate in the short term. The hydrogen-lithium coupling technology route combines the advantages of two battery technologies, in which the lithium battery can be used to start and provide a rapidly changing power output, and the hydrogen fuel cell can be used for energy output in the range, so as to meet the requirements of eVTOL for high power density and high energy density.
Chart: Hydrogen fuel cell and lithium-ion battery hybrid electric propulsion system
Source: Avionics Science and Technology Circle, CICC Research
We are bullish on eVTOL catalytic solid/semi-solid applications
We are optimistic that solid-state/semi-solid-state lithium batteries will become the mainstream technology route of eVTOL batteries in the future
Solid-state/semi-solid-state lithium battery technology is expected to be the mainstream technology route, and the Li-LMO system may be able to meet the energy density needs of suburban navigation. We believe that the current lithium battery technology is more mature and stable than hydrogen fuel cell technology, with better rate performance, and the solid-state battery route is also expected to break through the current lithium-ion battery energy density limit. According to Alexander Bills et al.'s research on the next generation of electric aircraft batteries, the longer the range and the larger the volume of the aircraft, the higher the need for batteries with higher energy density, of which the battery pack energy density of 500Wh/kg can support the regional aircraft with a passenger capacity of 30-75 people to achieve a flight range of about 230 kilometers, and the narrow-body aircraft with a passenger capacity of about 150-200 people to achieve a range of about 300 kilometers requires the battery pack energy density to reach 800Wh/kg. Considering the current number of eVTOLs and cruising range, we believe that the energy density of the Li-LMO system can reach 500Wh/kg, or support suburban navigation with a passenger capacity of less than 20 passengers (flight range of 200-300 km).
Chart: The larger the volume and longer the range of eVTOLs, which require batteries with higher energy density
Note: Regional aircraft have a range of 500 nautical miles (926 km) and a passenger capacity of 30-75 passengers, while Narrow narrow-body aircraft have a range of 1,000 nautical miles (1,852 km) and carry passengers between regional and wide-body aircraft, and Wide wide-body aircraft have a range of more than 2,000 nautical miles (3,704 kilometers) and a passenger capacity of 200-400 passengers
资料来源：《Performance Metrics Required of Next Generation Batteries to Electrify Commercial Aircraft》（Alexander Bills，2020），中金公司研究部
List of battery enterprise layout
► CATL [7]: In April 23, the company released condensed matter batteries, which have high specific energy and high safety. The energy density of the condensed matter battery is up to 500Wh/kg, according to the company's plan, the vehicle-grade products will have mass production capacity by the end of 2023, and the civil aviation will later, and currently work with partners to promote the development of civil electric manned aircraft projects, the company in July 23 with COMAC, Shanghai Jiaotong University Enterprise Development Group jointly established COMAC Times (Shanghai) Aviation Co., Ltd.
► Funeng Technology [8]: The company's ternary soft pack technology is mature, and it has mass-produced 285Wh/kg cells, which can support discharge rates above 10C, with a maximum speed of 320km/h, a maximum single cruise of 250km, and a cycle life of more than 10,000 times. In terms of customers, the company supplied the first samples to customers in the electric aircraft field in 2020, and subsequently completed the prototype certification, completed the delivery of the first-generation product in 2022 and completed the verification of the second-generation product system, and delivered the first-generation ternary product to the end customer in 2023. In terms of product research and development, the company expects that the 320Wh/kg battery cell will be mass-produced soon, and the 350Wh/kg battery cell has an A-sample prototype and is expected to achieve mass production in 2026.
► EVE [9]: The company released a 330Wh/kg semi-solid-state battery at the end of 22, which is currently in the stage of installation verification, and will launch lithium metal secondary battery products for the field of electric aircraft in 24 years, with an energy density of up to 500Wh/kg, a cycle life of more than 1,000 times, and can support 5C fast charging. At present, the company has laid out battery products in low-altitude fields such as flying cars and unmanned aerial vehicles, and promoted the cooperation of OEM customers at home and abroad.
► Gotion Hi-Tech [10]: In 22 years, the company launched semi-solid-state battery products for the first time, with an energy density of 360Wh/kg, and a ternary semi-solid-state battery with an energy density of 400Wh/kg is currently in the laboratory with prototype samples, and the company is expected to put into production in 25 years. In December 23, the company signed a strategic cooperation agreement with EHang to customize and develop EHang's unmanned eVTOL products, and tailor eVTOL power battery solutions that meet the airworthiness standards of the Civil Aviation Administration of China and "high safety, high energy density, high discharge power, and high quality standards". In addition, the company said that the cooperation between the two parties will also focus on the development of infrastructure such as high-power superchargers and energy storage systems to improve charging efficiency and jointly build a charging network to improve the operational efficiency of eVTOLs.
Chart: Solid-state/semi-solid-state battery layout of battery companies and eVTOL cooperation progress
Source: Company's official website, exchange investor interactive platform, CICC Research Department
How does eVTOL replenish energy?
Charging: The current mainstream eVTOL charging scheme, the charging time may be further shortened
Charging is currently the mainstream energy supplement solution chosen by eVTOL OEMs. Compared with battery swapping, charging and replenishing eVTOL does not require the purchase of redundant batteries (batteries account for 20% of the eVTOL cost), and does not require battery loading and unloading, and the core advantage is that the initial investment and subsequent operating costs are low; The ALIA N250UT can be charged in less than 50 minutes[11], and we believe that the subsequent increase in charging power may further reduce charging time, and considering the cost and benefits, charging may become the mainstream energy supplement solution for eVTOL in the future.
From the perspective of the construction cost of charging facilities, the principle of eVTOL charging is similar to that of electric vehicles, but the former has a larger battery pack capacity and higher requirements for charging power, resulting in differences in charging power, grid load and applicable scenarios between it and electric vehicle charging equipment, which ultimately leads to a significant higher construction cost of eVTOL charging equipment than electric vehicle charging equipment. According to the NREL study [12], the average cost of high-speed charging equipment (including equipment + construction cost) for public transportation in the United States is about 700,000 US dollars, and the peak power of these charging equipment is 325kW.
► Charging power: According to NREL study 2, the peak DC charging power of mainstream eVTOL is 300-1000kW, so the single-gun power of eVTOL charging equipment is generally 300kW and above, which is significantly higher than that of new energy vehicles, which is generally 60-80kW.
► Grid load: Due to the high charging power of eVTOLs per gun, which can significantly increase the load on the grid, NREL recommends that VTOL airports deploy a grid capacity of 1MW or more to ensure continuous operation.
► Applicable scenarios: eVTOL charging not only occurs on horizontal ground, such as vertical take-off and landing airports, but also on top of buildings. In addition, eVTOLs cannot autonomously approach the charging equipment like electric vehicles, and their take-off and landing points are still a certain distance away from the stationary charging equipment, so the eVTOL charging equipment requires a longer charging cable, such as 5-10 meters, to meet the eVTOL charging needs.
Case Study: Some eVTOL manufacturers have begun to deploy charging systems. The eVTOL companies currently announcing charging solutions mainly include Beta Technologies and Joby, the former of which uses a CCS charging interface that is widely used in new energy vehicles and has been recognized by competitors, and the latter has created the original GEACS charging system and hopes to be promoted in the global electric aviation field.
► Beta Technologies: Launched the Charge Cube product, which adopts CCS charging interface and can be used for eVTOL and new energy vehicle charging, with a continuous output of 320kW and a maximum charging voltage of 1000V. The product has been approved by competitors, and Archer has purchased several Charge Cube for charging its Midnight aircraft.
► Joby: Created a charging interface GEACS (Global Electric Aviation Charging System, referred to as GEACS) and released charger products based on GEACS. The maximum charging voltage of the product is 1000V, and the charging interface contains multiple DC channels, which can charge multiple independent redundant battery packs at the same time. Currently, the GEACS interface charger is in use at Joby's sites in California and Los Angeles.
Chart: Beta company Charge Cube charges eVTOLs
Source: Company's official website, CICC Research Department
Diagram: Schematic diagram of Joby's GEACS charger interface
Source: Company's official website, CICC Research Department
Power replacement: The speed of energy replenishment is faster, and the cost of investment, construction and operation and maintenance is higher
The speed of energy replenishment is faster, and the cost of investment, construction and operation and maintenance is higher. Compared with charging, the core advantages of battery swapping are 1) fast speed, it only takes about 5 minutes to change the battery, 2) the battery is charged slowly at a reasonable temperature after replacement, which can prolong the service life of the battery, 3) it can be charged when the electricity price is lower and arbitrage is realized, the disadvantages are mainly 1) the initial investment cost is high, one is the need to buy more batteries, the other is the need to build battery swap infrastructure, 2) the follow-up operating costs are high, including battery logistics costs, labor costs, etc., and 3) the eVTOL design needs to facilitate the daily replacement of the battery.
Case study: Volocopter uses battery swapping to replenish energy. At present, most eVTOL OEMs use charging for energy replenishment, but Volocopter believes that battery swapping can extend battery life, so it insists on using battery swapping for eVTOL energy replenishment.
Chart: Volocopter employees show off a battery swap on a Volocity model
Note: The staff here uses the model machine for display, and the actual battery weight cannot be displayed
资料来源：Vertical Flight Society，Volocopter，中金公司研究部
Chart: Conceptual diagram of the battery swap process for the Volocopter 2X
Source: Company's official website, CICC Research Department
Risk Warning
The policy implementation is less than expected. The eVTOL industry chain involves a wide range of developments, from parts and machine manufacturing to infrastructure construction and airspace management, all of which require greater policy support and more financial support. At present, the eVTOL industry chain is still in the early stage of the industry, and if the policy implementation is not as expected, it may affect the development of the entire industry chain and cause the industrialization of eVTOL to be less than expected.
The industrialization process is less than expected. The eVTOL industry chain is still in a relatively early stage, and there are key technologies such as flight controllers, batteries, and motors on the supply side that have yet to be broken through.
[1]https://wap.miit.gov.cn/zwgk/zcwj/wjfb/tz/art/2024/art_4ce8d09c15ee4fb1aefc3d5dfbbb6584.html
[2]https://www.gov.cn/zhengce/zhengceku/2022-01/07/content_5667003.htm
[3]http://zfxxgk.nea.gov.cn/2022-03/23/c_1310525630.htm
[4]https://www.gov.cn/zhengce/zhengceku/202308/content_6897986.htm
[5]https://www.gov.cn/zhengce/zhengceku/202310/content_6908243.htm
[6]https://mp.weixin.qq.com/s/VnNTs23gWrwjj6r05bnJyQ
[7]https://mp.weixin.qq.com/s/NbrIhsd5dM4InFGWcVxxvA
[8]https://mp.weixin.qq.com/s/ssbFLWCZO9WiRunxRLNFUQ
[9]https://irm.cninfo.com.cn/ircs/question/questionDetail?questionId=1580595967177318400
[10]https://mp.weixin.qq.com/s/4nynWsqazTa3LkpnOjJS7g
[11]https://www.beta.team/charge/
[12]https://www.nrel.gov/news/program/2024/electric-aircrafts-will-need-powerful-ports.html
Article source:
This article is excerpted from: "Low Altitude Flight Observation (3): What kind of batteries and infrastructure are needed for eVTOLs", which was published on April 23, 2024
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