New Energy Vehicle 800V High Voltage Platform Special Report: Technology Upgrade Brings New IndustryIssuing time:2024-04-01 16:05 New Energy Vehicle 800V High Voltage Platform Special Report: Technology Upgrade Brings New Industry Opportunities 1 800V high-voltage platforms are here to stay Improving the efficiency of energy replenishment is one of the key points in the development of new energy vehicle technology, and the 800V high-voltage fast-charging platform is getting closer. Range and replenishment efficiency are the concerns of some consumers when purchasing new energy vehicles. Currently, most electric vehicles have a range of 700 kilometers or less, and given the limited improvement in battery energy density in the short term, many manufacturers are focusing on replenishment efficiency. At present, most new energy vehicles adopt the 400V voltage platform, and after Porsche released the world's first car equipped with the 800V voltage platform in 2019, kicking off the prelude to the 800V high-voltage platform, a new round of releases has been launched by China's automobile enterprises in recent years, including BYD, Xiaopeng, Geely and other automobile enterprises. In the future, with the construction and improvement of the relevant supporting facilities of the 800V high-voltage platform, it will reduce the anxiety of new energy vehicle users to replenish energy, and lead electric vehicles into the era of comprehensive fast charging. 1.1 Domestic new energy penetration rate of nearly 30%, with ownership exceeding 10 million vehicles China's new energy vehicle market is developing rapidly, and the number of new energy vehicles has exceeded 10 million. China is the world's largest automobile producer, and the acceptance of new energy vehicles is gradually increasing. in 2022, the production and sales volume of new energy vehicles in China amounted to 7.041 million units and 6.872 million units respectively, doubling the year-on-year growth. By the end of December 2022, China's new energy vehicle ownership amounted to 13.1 million units. The penetration rate of new energy vehicles in China has exceeded 20%. in January 2022, the State Council issued the Comprehensive Work Program for Energy Conservation and Emission Reduction in the 14th Five-Year Plan, proposing that the sales volume of new energy vehicles would reach about 20% of the total sales volume of new vehicles by 2025. in 2022, the production and sales volume of automobiles in China amounted to 27.021 million and 26.864 million, respectively, representing a double growth year-on-year. In 2022, China's auto production and sales amounted to 27.021 million units and 26.864 million units respectively, with a growth of 3.4% and 2.1% respectively, and the proportion of new car production and sales accounted for 26.1% and 25.6% of new car sales, and the target of a 20% penetration rate in 2025 has been reached ahead of schedule. China's new energy vehicle market is dominated by pure electric vehicles, accounting for about 75%. New energy vehicles can be categorized into pure electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), programmable electric vehicles (REEVs) and fuel cell vehicles (FCEVs). in December 2022, China's new energy passenger car sales volume was 750,000, of which 563,000 were EVs and 187,000 were PHEVs, and the proportion of EVs reached 75%. At present, China's new energy vehicle market is still dominated by pure electric vehicles.
1.2 Enhancing range and accelerating replenishment efficiency are two key technology development direction Mileage anxiety and ease of charging are major concerns for potential consumers of new energy vehicles. The mode of operation of pure electric vehicles (PEVs) is to obtain electricity from the grid, store it in the power battery, and finally use the stored electricity to power the drive motor. Without considering fossil energy consumption and emissions at the power plant end, pure electric vehicles are a clean vehicle that does not consume fuel and has zero emissions. Although new energy vehicles have begun to see rapid development, for some consumers, there are still some concerns about purchasing new energy vehicles compared to traditional fuel vehicles, mainly in terms of range and convenience of charging. Therefore, in the technological development of new energy vehicles, improving the range and accelerating the efficiency of replenishment are two key directions. 1.Range: This can be achieved by increasing the amount of electricity carried by a single vehicle and lightweighting the vehicle. In 2020-2022, the single-vehicle carrying capacity of new energy passenger cars will continue to rise. According to the data of Power Battery Alliance, in 2020-2022, the single-vehicle charge of domestic pure electric passenger cars will be 48.04/48.58/50.51kwh respectively, which will be improved year by year, and the high range is still the direction of technological progress pursued by new energy vehicles. Battery capacity expansion or the use of lightweight materials can improve the range of new energy vehicles. Most of the new car-making forces in the market have a range of less than 700km, with the range of the Xiaopeng P5 being 460 and 600km, and the range of the Tesla Model 3 ranging from 468 to 675km. Therefore, for new energy vehicle enterprises, if they want to further improve the range of their vehicles to meet the demand for longer intercity driving, they should not consider adding battery capacity or adopting lightweight materials. Therefore, for new energy vehicle companies that want to further increase the range of their vehicles to meet the demand for longer intercity driving, they can increase the range of their vehicles by expanding the capacity of the batteries or adopting lightweight materials for the entire vehicle to reduce energy consumption through weight reduction, without considering the installation of range extenders. 2. Replenishment efficiency: High-voltage platform is the optimal short-term solution to replenishment anxiety The replenishment mode of new energy vehicles is categorized into power exchange mode and charging mode, with charging mode being the main mode. According to geographic location, power exchange/charging mode can be divided into stationary mode (the stationary mode of power exchange mode is power exchange station) and mobile mode.
1、Electricity exchange: high efficiency of replenishment, each car company launched a medium- and long-term planning to increase layout Power exchange mode is highly efficient in replenishing energy, and the representative manufacturer is Azalea Motor. The electric vehicle power exchange mode refers to the centralized storage, centralized charging, and unified distribution of a large number of batteries through centralized charging stations, and battery replacement services for electric vehicles at the battery distribution stations. Compared with the charging mode, the power exchange mode is more efficient in replenishing energy, and it can be divided into chassis power exchange, side power exchange and split box power exchange. Chassis power exchange can realize fully automatic power exchange without changing the weight of the front and rear axles of the vehicle, which greatly shortens the time of power exchange. Currently, chassis power exchange is adopted by both Azera and Aodong New Energy. In 2022, China's sales of new energy power exchange vehicles will nearly double, and the current number of power exchange stations nationwide exceeds 1,973. Internationally, power exchange mode has been popularized and applied to a certain extent in Israel, Canada, Australia and other countries, and Tokyo has also launched electric cab operation services combining charging and exchanging. By the end of 2022, China will have built 1973 power exchange stations for new energy vehicles, of which 1,300, 565 and 108 will have been built by Azure, AoDynamic New Energy and Hangzhou Botan respectively. After years of exploration, the domestic power exchange market has gradually formed two mature business models of "vehicle-electricity separation", namely the Azera BaaS model and Hangzhou Bertan's "battery bank" model. In the BaaS model, Azera, Ningde Times, and other contributors jointly set up a battery asset management company, which is responsible for the operation and management of the power exchange stations and the recycling of used batteries, while Azera provides 4-6 free power exchange services per month. The business model of "Battery Bank" is that the Battery Bank signs a cooperation agreement with vehicle manufacturers, whereby the Battery Bank finances the purchase of batteries and the consumer buys the vehicle without batteries, and then obtains the right to use the batteries in the form of a lease at a later stage.
For users, the power exchange mode has three major advantages: high replenishment efficiency and greatly shortened replenishment time: under the power exchange mode, the duration of a single power exchange is less than 5 minutes, and the replenishment experience is close to that of a fuel car; separation of vehicle and power reduces the purchase cost: power batteries account for 30-40% of the cost of a new energy vehicle, and the separation of vehicle and power under the power exchange mode significantly reduces the initial purchase cost of the consumer and lowers the threshold of the purchase. For example, the battery rental service baaS (Battery as a Service) launched by Azalea Motor can save customers 70,000 yuan or 128,000 yuan; prolonging the service life of the battery: under the power exchange mode, the battery is subject to unified supervision and management by the operator of the power exchange station, which not only increases the coefficient of safety, but also prolongs the service life of the battery through the operator's balanced optimization. Various enterprises have launched medium- and long-term plans to increase the layout of power exchange. Azure plans to have 4,000 power exchange stations worldwide by 2025; AoDynamic New Energy's development plan for 2021-2025 is to build more than 10,000 20-second power exchange stations; in addition, Geely Automobile, Lifan Group, Sinopec, GCL Energy, and the State Power Investment Corporation (SIPC) have all launched medium- and long-term development plans related to power exchange. 2. Charging: Compared with increasing current, increasing voltage is more in line with the future trend. Charging mode can be divided into fixed charging and mobile charging, of which fixed charging can be divided into three-hole sockets, AC charging piles and DC charging piles according to the charging device used. 1) Three-eye socket Three-eye sockets for home users are available in 10A and 16A sizes, corresponding to 2.2kW and 3.5kW. If a 16A socket is used, it will take about 8.5 hours to charge 30 degrees of electricity. 2) Charging Pile The difference between AC and DC charging piles lies in the different locations of the rectifiers required to convert AC and DC power. The power battery charging must be DC, and the part that converts the AC power output from the grid into DC power is the rectifier. When using an AC charging post, the rectifier in the EV converts the AC current to DC current, while a DC charging post has its own rectifier, which directly converts the output current to DC current for charging the battery. AC charging post: Due to the limitation of space inside the EV, the size of its on-board charging device can not be made too large, which leads to its current mainstream rated input current is only 16A or 32A, corresponding to the power of the charging post of 3.5kW and 7kW. For the charging post with a power of 7kW, assuming that the charging of 30 kilowatts of electricity, it will take about 4 hours. Although AC charging piles take longer to charge than DC charging piles, AC charging piles are more commonly used in community parking lots because they are less difficult to install; DC charging piles: due to the rectifiers, the charging time is longer than that of DC charging piles. DC charging post: Since the rectifier is installed inside the charging post, it can be installed without small space limitation, so its power is higher compared to AC charging post. When charging, the charging post needs to provide a voltage that matches the battery. Under the national standard 250A DC charging maximum output current and 400V voltage, the charging power of an EV is 100kW, which is much higher than that of AC charging post (7kW). 1.3 High-voltage platforms are the optimal short-term solution to replenishment anxiety For electric vehicles that use charging to supplement energy, increasing the charging speed essentially means increasing the charging power, and according to the electric power formula P=UI, an increase in current or voltage can increase the charging power.
Increase the current: the national standard limits the maximum current output, the current increase may cause demagnetization of the resistive element. Increasing the current is restricted by the international standard of 250A, and the charging power under 400V voltage is not more than 100kW. Increasing the current is a way to increase the power from the perspective of the electric power formula, but at present, it is still restricted by two factors, one of which is that the national standard stipulates that the DC charging output current should not be more than 250A (if automobile enterprises build their own charging piles, they are not subject to this restriction), so considering that the voltage platforms of the hot-selling models in China are generally around 400V, they can only obtain a charging power of not more than 100kW. Therefore, considering that the voltage platform of the current domestic hot-selling models is generally around 400V, it can only obtain a charging power not higher than 100kW, and the charging time is usually around half an hour to one hour. Tesla is the representative automobile company that adopts the method of increasing the current to increase the charging speed. Tesla has increased the charging power by increasing the current. The current of its first generation supercharger was 250A, while the peak current of the third generation is now more than 600A, which has increased the supercharging power from 100kW to 250kW. Some of its models can obtain a range of about 250km in 15 minutes under the peak power condition. Tesla expects the fourth generation of Supercharger to reach 350kW, and currently Tesla has opened more than 1,100 Supercharging stations and 8,600 Supercharging piles in mainland China. The high current puts higher demands on the thermal management and wiring harness, etc. The peak power of overcharging is only in the first half of charging. As the current continues to increase, the heat in the battery pack rises significantly, placing greater demands on the battery's thermal management system and wiring harness. The charging curve of the Model S Plaid on the V3 Supercharger shows that Tesla's Superfast Charge does not always maintain peak power at 250kW, but only maintains 250kW at 10%-32% of charge, and 180kW, 140kW, and 115kW at 40%, 50%, and 60% of charge. 800V High Voltage Platforms The 800V high-voltage platform can support faster charging for longer periods of time. According to research shared by Chao Wang, President of Huawei Smart Electric, when using low-voltage high-current mode, the maximum charging power only occurs during the 10%-20% SOC period, while the charging power decreases rapidly in the other intervals. However, in 800V high voltage mode, maximum power fast charging can support 30%-80% SOC. Therefore, the 800V high voltage mode can support faster charging for longer periods of time than the low voltage high current mode.
A second constraint to increasing the current is that it may cause demagnetization of the resistive element, whereas increasing the voltage reduces the risk of demagnetization for the same power. During the operation of an electric vehicle, heat loss occurs when electrical energy is converted into mechanical energy. Permanent magnet synchronous motors use permanent magnets as the rotor, and the rotor's motion is synchronized with the stator's magnetic field by a rotating magnetic field. As a huge resistive element, the PM synchronous motor generates a large amount of heat during operation. When the temperature exceeds 180℃, the motor will be demagnetized, which will affect the working efficiency of the motor and even cause damage to the product. Therefore, by increasing the platform voltage, the current can be reduced for the same power, thus reducing the heat generated by the motor and the risk of demagnetization when the resistance remains unchanged. Raising the voltage: kicking off the fast charging era Reducing the current reduces energy loss and also reduces vehicle weight by narrowing the cross-sectional area of the wiring harness. If the voltage can be increased from 400V to 800V with no change in current, the output power can be doubled from 100kW to 200kW under the national current limit of 250A, which significantly reduces the charging time. In addition to increasing output power, a higher voltage platform also reduces energy loss, i.e., for the same output power, an increase in voltage reduces the output current. According to the Joule equation = 2, when the voltage is increased to twice the original voltage, the current can be reduced to 1/2, which reduces the energy loss to 1/4. Therefore, increasing the battery voltage can improve the overall system efficiency. In addition, when the current is high, EVs need to use high-voltage wiring harnesses with large cross-sections to withstand high currents. As the current drops, the cross-sectional area of the wiring harnesses can be reduced accordingly, thereby reducing the cost of the wiring harnesses while reducing the weight of the vehicle. Most of the new energy vehicles nowadays adopt the 400V voltage platform, which is tens of times larger than that of the automobiles more than 100 years ago. The world's first battery car appeared in the 1910s, and even though its voltage was only 6V, it was a signpost to the "electrification" era. Since then, as engineers added various electric devices, such as lights and illumination, the power demand of vehicle electric power ushered in a period of rapid development. In the 1950s, the battery voltage was upgraded from 6V to 12V and was used for decades. Electric vehicles require a much higher voltage platform than fuel vehicles. In 2011, the five major German automobile brands Audi, BMW, Mercedes-Benz, Porsche and Volkswagen jointly released a 48V system, which is sufficient to cope with the on-board voltage requirements of fuel vehicles, but cannot meet the needs of electric vehicles without engines and gearboxes. Since the power pack voltage of an EV is over 100 volts, along with the distribution box, OBC, DCDC, electric drive, PTC, air conditioning, and charging ports, a voltage platform of 250V is required to sustain the daily use of an EV. In 2019, Porsche unveiled the world's first pure electric vehicle, the Taycan, equipped with an 800V voltage platform. When the charging power is raised to 270kW, it only takes 23 minutes to charge the Taycan from 0 to 80%. In addition, the high voltage increases the efficiency of charging and enhances the performance of the entire vehicle. The two permanent magnet synchronous motors in the Porsche Turbo S generate up to 460kW of output voltage, which enables it to reach a top speed of 260km/h and accelerate to 100km/h in just 2.8 seconds. Driven by Porsche, many manufacturers in the industry have begun to lay out 800V high-voltage platforms.
1.4 Domestic and Foreign Vehicle Enterprises Have Entered the Market, and the Prologue of 800V High Voltage Platform Has Begun With Porsche kicking off the prologue of the 800V high-voltage platform, China's car companies have also set off a new round of release fever. In recent years, BYD, Geely, Hyundai, Guangzhou Automobile, Xiaopeng, and JFX have successively released models equipped with the 800V high-voltage platform, among which Xiaopeng and BYD have set the mass production of the 800V platform models for 2022. Models currently on the market using the 800V platform system include the Porsche Taycan, Audi e-tronGT, Hyundai IONIQ 5, and the Kia EV6. although the Lucid Air limousine uses the 900V architecture, it is still technically an 800V system. 1. Xiaopeng Automobile Xiaopeng Automobile's 800V platform makes simultaneous efforts at the three ends of the vehicle, pile and station to improve the charging efficiency of electric vehicles in all aspects. At the vehicle end, Siu Peng Auto is China's first mass-produced 800V high-voltage SiC platform, supporting a maximum current output of 600A, with an electric drive efficiency of more than 95%, realizing a "5-minute charge, 200km range"; at the pile end, Siu Peng Auto researches and develops its own 480kW high-voltage super-charger, which takes 12 minutes to charge from 10% of the power to 80%, and focuses on lightweight design at the same time. At the pile end, Xiaopeng Automobile has developed its own 480kW high-voltage supercharging pile, which takes only 12 minutes to charge from 10% to 80% of the power, and pays attention to the lightweight design in the construction. 2、Hyundai Motor Hyundai unveiled the E-GMP platform with the world's first 800V high-voltage charging system. In December 2020, Hyundai unveiled the E-GMP platform (Electric-Globa lModular Platform), which features the world's first 800V high-voltage charging system, and electric vehicles developed based on the E-GMP platform support four-wheel drive, enabling acceleration time of 100km to be reduced to 3.5 seconds, top speed to reach 260km/h, and a range of 600km (NEDC). Electric vehicles developed on the E-GMP platform support four-wheel drive and can accelerate to 100 kilometers in 3.5 seconds, reach a top speed of 260 km/h and have a range of 600 km (NEDC conditions). With high voltage, the electric vehicle can be recharged to 80% in just 14 minutes, and the E-GMP platform utilizes an all-in-one electric drive system with SiC power devices, which provides a 2-3% efficiency improvement over conventional silicon-based power devices and extends the range by around 5%. 3、Dongfeng Lando Dongfeng Lando's self-developed 800V high-voltage platform can achieve a range of 400km in 10 minutes of charging In September 2021, Dongfeng Lando demonstrated its self-developed 800V high-voltage platform and super fast-charging technology at the autumn conference, of which the latest 800V high-voltage super fast-charging technology is a new high-voltage system architecture in which the power batteries and power-using equipments are 800V high-voltage systems with no redundant boosting devices. The latest 800V high-voltage super fast-charging technology is a new high-voltage system architecture with 800V high-voltage system for both power battery and power-using equipment, without redundant boosting device, including super fast-charging system, ultra-low system energy consumption, high-performance battery, SiC electric drive assembly, and supporting wireless charging. Among them, the high-performance battery of the whole vehicle is equipped with 4C battery cells, and with the support of 360kW super charging piles, the charging rate can be increased by 125%, realizing a range of 400km in 10 minutes of charging.
4、BYD BYD's exclusive pure-electricity platform e Platform 3.0 can realize 150km driving in 5 minutes of charging. In September 2021, BYD officially released its exclusive pure-electricity platform e Platform 3.0, which is equipped with the world's first eight-in-one electric powertrain as a standard feature, enabling acceleration of 0.100 to 2.9s, and a comprehensive driving range of up to 1,000km. In addition, with the 800V flash charging technology, the EV can realize 150km driving in 5 minutes of charging, and the winter driving range can be increased by up to 20%. In addition, with 800V flash charging technology, the EV can be charged for 5 minutes and driven for 150km, and its winter range can be increased by up to 20%. 5.Geely Extreme Krypton Geely Extreme Krypton 001 can travel 120km in 5 minutes of charging. 2021 April, Geely's high-end pure electric brand Extreme Krypton's first model, Extreme Krypton 001, is the first production model based on the SEA Vast Architecture, with two voltage architectures, 400V and 800V, and a charging time of 30 minutes for 10%-80% SOC, which allows it to travel about 120km in 5 minutes of charging. In addition, it is equipped with the "Extreme Core" battery pack with liquid-cooled temperature control management system, which is capable of reaching a high charging rate of 2.2C and a maximum charging current of up to 600A. 6.GAC Extreme Fox The GAC Alpha S Huawei HI Edition can drive 200km in 10 minutes on an 800V high-voltage platform.2022 In May, the GAC Alpha S Huawei HI Edition will be launched on the market.Relying on the country's first high-voltage 800V mass-production vehicle platform, the charging power of the GAC Alpha S can reach up to 187kW, and it can drive 200km in 10 minutes on a 10-minute charge, with the charge going from 30% to 80% in just 15 minutes. 7.GAC-EAN GAC-EAN can achieve a range of 200km in 5 minutes on the A480 super charging post.2021 In August 2021, GAC-EAN unveiled its Super Speed Battery technology with its A480 super charging post, which has a voltage of up to 880V and a maximum charging power of 480kW. 6C high-rate charging can be achieved on its A480 super charging post, with the range increasing to 200km in 5 minutes of charging. The range can be increased by 200km in 5 minutes.
2 800V high-voltage platform leads to the upgrading of industry chain links Although increasing the voltage can reduce the charging time of EVs, the technology upgrade is a complicated systematic project. At present, most of the existing DC fast-charging infrastructure basically serves 400V vehicles, so if we want to complete the ecological construction of the 800V platform, in addition to upgrading the vehicle accessories, we also need to support the corresponding external charging facilities. The internal accessories include the core three power systems, air conditioning compressor, DCDC (DC transformer), OBC (on-board charger) and other components, while the external accessories are charging piles and charging stations. 1、Battery The lithium precipitation phenomenon caused by high voltage will lead to the decline of battery capacity and even lead to safety accidents. For batteries, the voltage can be adjusted by adjusting the number of series and parallel connections of the battery cells, but the main difficulty lies in how to ensure the safety and service life of the batteries in the case of high voltage and high current. Excessive charging voltage or current may cause the stability of electrode materials and electrolyte of Li-ion batteries to decrease, resulting in increased side reactions and lithium precipitation on the surface of the anode, which leads to an increase in the internal resistance of Li-ion batteries, capacity degradation, and even lead to fire, explosion and other potential safety hazards. The realization of 4C and above charging multiplier requires breakthroughs in battery materials and BMS with high control precision. Currently, mainstream power battery packs can support 2C charging multiplier, and through the use of electrolyte additives, isotropic graphite, graphene and other materials, the conductivity of battery materials can be improved to a certain extent, thus improving the stability of ternary materials under high voltage. However, these solutions cannot fundamentally avoid the occurrence of side reactions, and breakthroughs in battery materials and high-precision BMS (battery management system) are still needed to realize ultra-fast charging at 4C or even higher charging rates.
2. Electric drive system SiC is more suitable for electric vehicles on the 800V platform due to its high withstand voltage, low conduction loss and low switching loss. The higher voltage requires higher insulation capability, voltage withstand level and creepage distance, and the difficulty lies in the core components of the motor controller, i.e., power semiconductor devices. Among the current power semiconductor devices that meet automotive standards, the most mainstream silicon-based IGBTs have a voltage withstand level of 600-750 V. If the DC bus voltage is increased to 800 V or more, the voltage withstand level of the corresponding power device will need to be increased to about 1200 V. In this case, SiC is the most suitable for the motor controller. In this case, SiC is more suitable for electric vehicles on the 800V high-voltage platform due to its characteristics of high withstand voltage, low conduction loss and low switching loss. SiC is also available in a MOSFET package at 1200 V, which extends the voltage rating to 1200 V. However, it will take some time for SiC to gain popularity as it is still not comparable to IGBTs in terms of capacity and cost. In addition, the increase in voltage not only affects the battery and electric drive system, but also puts higher demands on components such as air-conditioning compressors, PTCs, DCDCs, and on-board chargers. 2.1 800V High Voltage Platforms Desperately Need Negative Electrode Performance Improvement The fast charging of Li-ion batteries is constrained by the lithium precipitation at the anode. When charging lithium-ion batteries, Li+ is de-embedded from the positive electrode and embedded in the negative electrode, but when there are some abnormal conditions, such as insufficient space for lithium embedded in the negative electrode, too much resistance to Li+ embedded in the negative electrode, Li+ is de-embedded from the positive electrode too quickly but it is difficult to embed in the negative electrode in an equal amount, Li+ that can not be embedded in the negative electrode can only get electrons on the surface of the negative electrode, thus forming a silvery-white lithium monomers, which means that "lithium precipitation" phenomenon has occurred. "precipitation lithium" phenomenon. Lithium precipitation not only makes the battery performance decline, cycle life is greatly shortened, but also limits the fast-charging capacity of the battery, and this effect is almost irreversible. In addition, lithium precipitation may cause combustion, explosion and other disastrous consequences. Therefore, the fast charging of lithium-ion batteries is constrained by lithium precipitation at the anode, and the possibility of lithium precipitation needs to be reduced if the charging efficiency is to be improved. Anode materials for lithium-ion batteries mainly include carbon-based and non-carbon based anode materials, while carbon-based anode materials have the widest application scope due to their good electrochemical performance, low difficulty in material acquisition and low price. Currently, there are two main methods to reduce the possibility of lithium precipitation in lithium-ion battery anode under high pressure, one is to modify graphite, and the other is to use non-carbon based anode materials. 1、Graphite modification There are three main methods, including oxidation modification, coating modification and etching modification. (1) oxidation modification: oxidation process is divided into gas phase and liquid phase oxidation. Gas-phase oxidation mainly reacts on the interface between gas and graphite. Oxidation can improve the surface structure of graphite, facilitate the capacity increase and reduce irreversible capacity loss, thus improving the cycle performance. However, the disadvantage of gas phase oxidation is that oxidation only occurs at the surface of the graphite where the gas is in contact with the graphite, so that the oxidizing effect is reduced if the contact surface is small. Liquid phase modification is a process in which the oxidation is accomplished in a liquid phase system. Since the reaction is done in the liquid phase, the degree of oxidation can be controlled by adjusting the concentration of the liquid, and the homogeneity of the prepared samples is better. Compared with gas-phase oxidation, the liquid-phase method is simpler, but its shortcomings are the need for post-treatment, and the oxidizer has a certain degree of corrosiveness to the equipment. (2) Coating modification: Graphite and amorphous carbon have their own advantages and disadvantages, so the two can be combined, and the disordered carbon layer structure inside the amorphous carbon can realize the rapid embedding of Li+ under the high-voltage platform. (3) Etching modification: The use of strong alkali to etch the graphite can form pores on the surface of the graphite, and the increase in the number of pores can greatly improve the number of lithium-ion embedding and detachment sites, and reduce the diffusion distance of lithium ion in the lithium-ion batteries. lithium-ion battery, and reduce the diffusion distance of lithium ions in the lithium-ion battery. 2. Silicon-based materials as anode Silicon-based materials have a capacity of 4200 mAh/g, much higher than carbon's 372 mAh/g. Silicon-based materials have higher embedded lithium potentials, which means there is less risk of lithium segregation, and therefore they can tolerate higher charging currents than carbon-based batteries. 2.2 800V high-voltage platform will promote the construction of charging piles and energy storage supporting facilities The low ratio of pile-vehicle ownership is favorable to the development of 800V high-voltage platform. For charging piles, in 2022, the incremental volume of China's charging infrastructure will be 2.593 million units, and the ratio of pile-vehicle incremental volume will be 1:2.7. Although this value is improved compared with 1:3.7 in 2021, it is still lower than China's target of 1:1 vehicle-to-vehicle ratio. As of December 2022, China's charging pile and new energy vehicle ownership were 1.797 million units and 13.100 million vehicles respectively, with the ratio of pile-vehicle ownership at 1:7.3, and the large gap in charging pile is favorable to the development of China's 800V high-voltage platform industry. At present, many automobile enterprises have launched super charging piles adapted to high-voltage platforms. Xiaopeng Automobile self-developed 480kW high-voltage super charging pile, 10%-80% SOC in 12 minutes; Lantu Automobile, with the support of 360kW super charging pile, the charging rate can be increased by 125%, realizing charging in 10 minutes and a range of 400 kilometers; GAC A480 super charging pile released by EAN, the voltage can be up to 880V, with a maximum charging power of 480kW, realizing charging in 5 minutes and a range of 200 kilometers. The A480 super charging pile released by GAC EAN has a voltage of 880V and a maximum charging power of 480kW, which can realize a charging time of 5 minutes and a range of 200km. The acceleration of the construction of high-voltage charging piles is conducive to the rapid development of electric vehicles equipped with high-voltage electric platforms.
The widespread use of 800V charging systems will put a certain amount of pressure on the power grid, and the high voltage of 800V can significantly improve charging efficiency and thus shorten charging times. However, there are currently few charging piles that are compatible with the 800V platform, and even the Porsche Taycan, which is equipped with 800V high-voltage technology, can only achieve a maximum charging power of 200kW under the national standard 250A current limit. Therefore, when the 800V charging system is widely used, the charging load of the power grid will face greater pressure. Xiaopeng Auto has developed its own energy storage charging technology, which will meet the demand for uninterrupted high-power charging for 30 vehicles at a time. At the Xiaopeng Technology Day on October 24, 2021, Xiaopeng Auto introduced its progress and plans in the field of fast charging, including the 800V high-voltage SiC platform, 480kW high-voltage charging piles, and energy storage charging technology. Among them, the peak charging current of 800V high-voltage SiC platform exceeds 600A, so the maximum power reaches 480kW. In order to ensure the normal operation of high-power supercharging station and ease the pressure of power grid, Xiaopeng Auto will bring its own self-developed energy storage charging technology to the station end, which is able to satisfy the demand for uninterrupted high-power charging of 30 vehicles with one time energy storage, and adopts the two methods of energy storage supercharging station and mobile energy storage vehicle to bring the users a better and more convenient charging experience by shaving peaks and filling valleys, and providing the users with a better and more convenient charging experience. The use of both supercharging stations and mobile energy storage vehicles reduces the pressure on the power grid by cutting peaks and filling valleys, while providing users with an efficient energy replenishment experience. In the future, with the gradual popularization of the 800V high-voltage platform, energy storage charging technology will also usher in a rapid development phase. (This article is for information purposes only and does not represent any investment advice on our part. To use the information, please refer to the original report.) |
