What is EV 800V fast charging?

“Charge for 5 minutes, drive for 200 kilometers”-the advertising slogan of 800V high-voltage fast charging is exciting, but you may not know: there are “true and false” 800V on the market.

When the sales consultant enthusiastically introduces the “800V fast charging technology”, you might as well ask one more question: “Is this the real 800V?”

Many consumers are still kept in the dark: true 800V is a technological revolution of high-voltage reconstruction of the whole link from battery, electric drive to air conditioning compressor, and the charging power can steadily exceed 300 kW; However, the fake 800V may be a “marketing gimmick” of local boost, with a sudden drop in power, a shrinking charge, or even only 60% of the charge in half an hour.

Behind the word game is the cost difference and technical compromise: true 800V needs to invest in silicon carbide chips and global high-voltage design, which increases the cost by 20,000-30,000 yuan; The fake scheme only relies on the charging port to boost the voltage, so it dares to flaunt “800V fast charging”.

How to see through the trick? This article will teach you to see through the true and false 800V at a glance from the three dimensions of voltage range, component coordination and measured curve, and refuse to pay for the fake technology.

1. Principle

Technical principle of 800V fast charging:

The charging speed of an electric vehicle is determined by the charging power, which is equal to the voltage multiplied by the current (P = U × I). To achieve super fast charging, either increase the charging current or increase the charging voltage.

Traditional 400V platform electric vehicles mainly increase power by increasing current, but excessive current will lead to a sharp increase in wire heating and loss, which puts forward extremely high requirements for cables and cooling systems.

Therefore, 800 V high-voltage fast charging adopts the technical route of “high voltage, low current”, which significantly reduces the current while maintaining or improving the charging power, thus reducing the heat and loss.

It should be noted that “800V” is not a precise value, but means that the voltage range of the vehicle’s high-voltage electrical system is roughly between 550 V and 930 V (the middle value is about 800 V).

Before the emergence of the 800 V system, the voltage range of the mainstream electric vehicle high-voltage system was about 230V – 480V, collectively referred to as the 400 V platform. Therefore, 800V fast charging is essentially a technical scheme for fast charging of batteries under a higher voltage platform. Its core principle is to greatly increase the charging power by increasing the voltage, while avoiding the negative impact of excessive current.

 

2. Structure

Structure of 800V fast charging system:

The 800 V fast charging system involves a complete set of high-voltage electrical architecture from the charging infrastructure to the interior of the vehicle, mainly including high-voltage battery packs, charging interfaces and cables, on-board charging control devices, and high-voltage distribution and conversion systems.

• High voltage battery pack:

The power battery pack of the 800V platform consists of a large number of cells connected in series, and the rated voltage is significantly higher than that of the traditional 400V battery pack. The battery management system (BMS) is responsible for monitoring and managing the status of each battery cell to ensure that the battery voltage, temperature and other parameters are in a safe range during the fast charging process.

• Charging interface and cable:

800V fast charging requires a charging interface and cable supporting high voltage. At present, the design of fast charging interfaces such as CCS Combo 2 has taken into account the need for higher voltage, but in order to carry more power, charging guns and cables usually need to use liquid cooling technology to dissipate heat. The charging socket and interface at the vehicle end are also designed with reinforced insulation and safety to adapt to 800 V high voltage.

• On-board charging control device:

Inside the vehicle, the 800V fast charging system includes a charging control unit and an associated power conversion device. When the charging gun is connected to the vehicle, the charging point first provides a low-voltage auxiliary power supply to activate the BMS in the vehicle. Subsequently, the vehicle end and the pile end confirm the charging parameters (such as the maximum voltage and current required by the vehicle, the output capacity of the charging pile, etc.) through communication. After confirming the match, the BMS of the vehicle sends a charging command to the charging pile, and the charging pile adjusts the output voltage and current accordingly to start charging the battery. This process is completed by the on-board charging control unit and BMS to ensure that the charging process is safe and controllable.

• High Voltage Distribution and Switching Systems:

The vehicle high voltage electrical architecture of the 800 V platform requires corresponding power distribution and voltage conversion devices. For example, the vehicle’s high-voltage power distribution box (PDU) needs to be able to distribute 800 V power to various subsystems, including motor inverters, air conditioning compressors, DC/DC converters, and so on. Since the low voltage equipment in the vehicle (such as 12V electrical appliances) still needs power supply, the 800V system is usually equipped with a high voltage DC/DC converter to reduce the 800 V DC to 12 V or 48 V for the on-board low voltage network. In addition, some 800 V models will be equipped with voltage conversion devices to be compatible with existing 400 V charging piles. For example, Porsche Taycan adds a “charge pump” boost converter in the car, which can boost the DC of 400 V charging point to 800 V to charge the battery. This additional DC/DC boost module, although increasing cost and volume, ensures that the 800V model can be charged on the existing charging network.

 

In general, the structure of the 800 V fast charging system is based on the traditional electric vehicle electrical architecture, and the battery, charging interface, power distribution and conversion devices are fully upgraded to adapt to higher voltage and power. This whole set of structures works together to realize that the electric vehicle can replenish electric energy at a much faster speed than before on the premise of maintaining safety.

 

3. Composition

Key components of 800V fast charging system:

To achieve 800 V high-voltage fast charging, vehicles and charging facilities need the cooperation of several key components, including high-voltage batteries, high-power charging modules, silicon carbide power devices, high-voltage connectors and relays.

• High voltage battery:800 V fast charging can not be separated from the power battery with high voltage and high rate. Battery packs typically consist of hundreds of cells connected in series to achieve a total voltage of nearly 800 V. At the same time, in order to support fast charging, the material and design of the battery core need to be optimized, such as the use of electrode materials with better conductivity, improved electrolyte formulation, etc., to withstand large current charging without damage such as lithium deposition. At present, the battery capacity of mainstream 800V models is more than 80 – 100kWh to provide long endurance, while supporting charging rates of 3C or even more than 4C.
• High Power Charging Module:

Inside the DC fast charging pile, the core is a high-power power conversion module. A typical DC fast charging pile adopts a two-stage architecture of “AC/DC rectification + DC/DC conversion”. First, the rectifier converts the three-phase AC into about 800 V DC bus voltage, and then the DC/DC converter adjusts the voltage to the charging voltage required by the battery and outputs a large current. The power module of 800V fast charging pile is usually composed of several sub-modules in parallel to achieve a total power output of hundreds of kilowatts. For example, a 350 kW charging station may consist of ten 35 kW power modules connected in parallel. These modules need to be extremely efficient and heat-dissipating to deliver high power while minimizing losses.

• Silicon Carbide (SiC) Power Devices:

Due to the higher voltage and frequency of 800V system, the traditional silicon-based IGBT is difficult to meet the demand in terms of switching loss and high temperature resistance, so silicon carbide power devices become one of the core components of 800V fast charging. SiC material has the advantages of large band gap, high breakdown field strength, high thermal conductivity and the like, and can be used for manufacturing power devices with high voltage resistance, low on-resistance and high frequency switching. In 800V electric vehicles, SiC MOSFETs are widely used in motor inverters, on-board chargers (OBCs) and DC/DC converters, which can significantly reduce switching losses and improve system efficiency. For example, Hyundai Kia’s E-GMP 800V platform uses a large number of SiC power modules, which improves the efficiency of the electric drive system by 5 – 8%. At the same time, SiC devices can also work stably at high temperature, which helps to simplify the heat dissipation design. It can be said that silicon carbide devices are the key to give full play to the performance of 800 V high voltage platform, and their application makes high voltage and high frequency power conversion possible.

• 3D rendered silver rectangular electronic component, maybe an inverter or power module
• High-voltage connectors:The electrical connection of the 800V system places higher demands on the connectors. High-voltage connectors must have good insulation and current-carrying capacity, and be able to safely transmit voltages of 800 V or more and currents of hundreds of amperes. Connectors also need to meet safety standards for protection against electric shock (e.g., with a protective cover), water and dust resistance (typically IP67), and mechanical locking. The charging interface for the 800V model, such as the CCS Combo 2, is physically similar to the 400 V interface, but the internal conductors and insulation are reinforced to withstand the electric field strength at higher voltages. In addition, the high-voltage wiring harness connector inside the vehicle has also been upgraded to 800 V level to ensure reliable connection between batteries, inverters, chargers and other components.
• High-voltage relay:relay (contactor) is used for on-off control of high-voltage circuit, which is also indispensable in 800 V system. 800V high voltage relays need to withstand higher rated voltage and current, and have stronger arc extinguishing ability. When the battery is charged or discharged, the relay closes the circuit; and when the battery fails or needs to be disconnected, the relay is quickly disconnected to cut off the high-voltage circuit and ensure safety. 800 V systems typically have a main relay on both the positive and negative battery terminals, and some are equipped with a pre-charge relay for soft start. These relays must be rigorously tested to ensure long-term reliability and safety at 800 V.

 

To sum up, the 800 V fast charging system consists of key components such as high voltage battery, high power charging module, SiC power device, high voltage connector and relay. These components work together to enable electric vehicles to charge quickly with hundreds of kilowatts of power, while ensuring the efficiency and safety of the system.

4. Role

Functions and advantages of 800V fast charging system:

800 V high-voltage fast charging technology is regarded as an important solution to alleviate the “range anxiety” and “charging anxiety” of electric vehicles, and its core role is to greatly improve the charging efficiency and vehicle performance, and bring many advantages.

• Faster charging:This is the most intuitive function of 800 V fast charging. By increasing the voltage, the charging power is significantly increased, thereby significantly reducing the charging time. For example, the Porsche Taycan with 800 V fast charging can charge from 5% to 80% in 22.5 minutes, which usually takes about 1 hour on the 400 V platform.
• Better drive performance:
• The 800V high voltage platform is not only conducive to charging, but also improves the dynamic performance of the vehicle. A higher voltage means a higher power output at the same current. Therefore, the motor inverter of 800 V electric vehicle can output more power and torque with the same volume. For example, the power performance of 72V electric motorcycle is much better than that of 36V battery car. Similarly, the acceleration performance of 800V platform electric vehicle is often better than that of 400V platform vehicle. In addition, the working mode of high voltage and low current also reduces the loss and heat of the motor and electronic control system, making the power output more efficient and lasting.
• More efficient systems:

Due to the reduced current, the energy loss of the 800 V system during transmission and conversion is significantly reduced. According to Joule’s law, the loss is proportional to the square of the current, so reducing the current can greatly reduce the heat loss. When charging, the 800 V high voltage reduces the heating of the charging cable and connector, and improves the charging efficiency; When driving, low current means that the copper loss of motor, inverter and wiring harness is reduced, the power consumption of the whole vehicle is reduced, and the range is increased in a disguised way. At the same time, the 800 V system generally introduces silicon carbide power devices, which have much lower switching losses than traditional silicon devices, further improving the efficiency of the electric drive system. Data show that the efficiency of 800 V electric drive system using SiC can be increased by more than 5%. Higher efficiency means that vehicles can run farther with the same battery capacity, or achieve the same endurance with smaller batteries, thus reducing vehicle weight and cost.

• Reduced weight and simplified design:

An 800 V system draws only half as much current as a 400 V system when delivering the same power, so the harness can be thinner in diameter and lighter in weight. This not only reduces the material cost, but also helps to reduce the weight of the whole vehicle. Thinner cables are also easier to route, improving space utilization. In addition, due to the reduction of current, the specification requirements of electrical components (such as contactors, fuses, etc.) are reduced accordingly, and in some cases, smaller components can be used. All these help to optimize the vehicle design.

• Great potential for future expansion:

The 800V platform has reserved space for further improvement of charging power. At present, the power of the mainstream fast charging pile is about 350 kW, but the 800V architecture can fully support higher power (such as 480 kW or even 600 kW) charging equipment. In the future, with the progress of battery technology and heat dissipation technology, 800V system is expected to achieve the goal of “charging for 5 minutes, lasting 300 kilometers” or even higher. In addition, the high voltage of 800 V also provides a larger power margin for other electrical equipment of the vehicle (such as high-performance air conditioning, electric heating, etc.), which is conducive to the introduction of more advanced functions.

 

Generally speaking, the function of the 800 V fast charging system is to exchange higher voltage for faster charging speed and better performance. It significantly alleviates the energy supplement anxiety of electric vehicles, improves the convenience of use, and improves the efficiency and endurance performance of the whole vehicle by reducing the loss and optimizing the design. For this reason, 800 V high-voltage fast charging is regarded as an important direction for the development of electric vehicle technology.

 

5. Features

Technical features of 800V fast charging system:

As a new generation of electric vehicle charging technology, 800 V fast charging has a series of distinct technical features, including high voltage, high power, high efficiency, and compatible design with the existing charging system.

• High voltage and wide voltage range:The nominal voltage of the 800V fast charging system is significantly higher than that of the traditional system, and the working range is usually between 550V and 930V. This wide voltage range allows the battery to be quickly charged at a high voltage of nearly 800 V in the initial stage of charging, and the voltage is gradually reduced with the increase of SOC to maintain a high power. In contrast, the voltage range of the 400 V platform is mostly 230 V – 480 V. The direct benefit of high voltage is that it can be charged with higher power, while the low current reduces losses. It should be noted that “800V” is not an absolute constant value, the full voltage of the battery of different models may reach more than 900 V, and the voltage at the end of discharge may also drop to more than 500 V. Therefore, 800V is more a general term for this generation of high-voltage platform.
• Ultra-high charging power:

With high voltage, 800 V fast charging supports hundreds of kilowatts of charging power. At present, the 800 V fast charging power of mass-produced vehicles is about 350 kW, and some models and charging piles even reach 480 kW or higher. Such a high power means that the charging speed has more than doubled compared with the 400 V era. Of course, the actual charging power is also limited by the battery status (such as temperature, SOC) and the charging pile capacity, but the 800 V system undoubtedly opens the door to “charge for 5 minutes and last 100 kilometers”.

• High efficiency and low loss:

The 800V fast charging system has higher efficiency in energy conversion and transmission. On the one hand, line losses and heating are significantly reduced due to the reduced current. On the other hand, the 800 V platform uses a large number of efficient silicon carbide power devices, and its switching loss is much lower than that of traditional silicon devices. For example, the use of SiC MOSFETs can improve the efficiency of electric drive systems by 5 – 8%. Coupled with advanced topology design and control strategies, the overall efficiency of 800 V charging systems is typically above 90%. High efficiency means less wasted energy and lower operating costs, as well as reduced cooling requirements and improved system reliability.

• Compatible with existing charging networks:

Despite the outstanding performance of 800V systems, compatibility with existing 400V charging facilities has been designed by major manufacturers for the convenience of users. 800V electric vehicles can generally be charged on 400V DC charging piles, but the charging power will be limited by the output capacity of the piles. For example, some engineers pointed out that “800 V high-voltage platforms are also compatible with 400 V DC fast charging piles, but the charging voltage is less than 800 V, and the charging efficiency is almost the same as that of ordinary 400 V vehicles”. In order to improve the charging speed on the 400V pile, some 800V models have adopted special design. Either way, it is to take into account the existing charging system, so that 800V models can still charge normally before 800V charging piles are fully popularized, but the efficiency is different.

• Safety and protection design:

High voltage also puts forward higher requirements for the safety design of the system. 800V fast charging system has special design in insulation protection, overcurrent protection, leakage detection and so on. For example, the vehicle’s High Voltage Interlock (HVIL) circuit monitors the connection status of all high voltage connectors and cuts off the high voltage as soon as it is disconnected. The charging interface is designed with safety lock and anti-misplug to prevent accidental gun pulling or wrong connection during charging. In addition, strict handshake and status monitoring between vehicles and charging piles are carried out through communication protocols (such as ISO 15118) to ensure that charging is carried out under safe conditions. When abnormal conditions such as over-temperature, over-voltage or leakage are detected, the system will quickly interrupt charging and give an alarm. It can be said that while 800V fast charging pursues high power, the safety redundancy design is more perfect to ensure the safety of users and vehicles.

 

To sum up, the characteristics of the 800 V fast charging system can be summarized as: high voltage, high power, high efficiency, compatibility with the existing network and higher safety standards. These characteristics make it a highlight of the current electric vehicle technology, and also represent the future development direction of charging technology.

6. Identification method

How to distinguish between true and false 800V fast charging system:

With the popularity of 800V concept, there are some models on the market that claim to support 800V fast charging but are not worthy of the name. When consumers choose or understand 800V models, they can distinguish their authenticity and technical level by the following methods:

• Look at the battery voltage and charging power:
• True 800 V fast charging requires both the battery and the charging system to meet high voltage standards. First check the rated voltage of the vehicle battery pack. If the official battery voltage is only more than 500 volts, it can only be regarded as a “quasi-800 V” platform. A true 800 V system with charging points above 350 kW should be able to achieve a charging peak close to 350 kW. If a car number supports 800 V fast charging, but can only charge to about 150 kW on 350 kW piles, it is likely that the battery voltage is slightly higher and other parts are not upgraded, which belongs to “pseudo 800 V”. Simply put, high voltage must be matched with high power, otherwise it is in vain.
• Look at the high-voltage structure of the whole vehicle:

The advantage of 800 V platform lies in the global high voltage, that is, from the battery to the motor, electronic control, on-board charger and other key components are designed with 800 V. If a car only upgrades its battery to 800 V, while the electric drive system, air conditioning compressor, DC/DC converter and so on still use 400 V components, then it is at best “half a set of 800 V”. This “pseudo-upgrade” will lead to no significant improvement in vehicle performance other than charging, and even increase losses due to the need for additional voltage conversion. The identification method is to consult the technical data of the vehicle to see whether the motor controller, OBC, air conditioner, etc. Are 800 V specifications and whether SiC devices are used. If these core components are not upgraded, even if the battery is nominally 800V, it will be difficult to give full play to the advantages of the real 800V platform.

• Look at the charging current:

Since the 800 V system is designed to reduce the current, its charging current should be significantly lower than 400 V system at the same power. For example, a 400 V system at 350 kW requires about 875 A, while an 800 V system requires only about 437 A. Therefore, it can be judged by the current value at the time of charging. If the current of a “800V” vehicle is maintained at six or seven hundred amperes or even higher for a long time during fast charging, it means that its actual working voltage may be much lower than 800 V. Real 800 V fast charging usually has a current of about three or four hundred amperes in the peak power stage. Users can check the real-time current through the charging pile display screen or vehicle instrument during charging to assist in judging the charging system level of the vehicle.

• Look at the actual charging speed:

Practice is the only criterion for testing truth. For vehicles claiming 800 V fast charging, you can refer to the actual charging test data. For example, on a charging point supporting 350 kW, how long does it take to charge the battery from 10% to 80%? If it still takes more than 30 minutes, it means that its fast charging capacity is the same as that of an ordinary 400V vehicle. On the contrary, the true 800 V model should be able to complete this interval charging in about 20 minutes when conditions permit. In addition, we can also pay attention to the charging curve: due to the high voltage, the 800 V vehicle can often maintain high power charging in a wider SOC range, and the curve is relatively gentle; However, the pseudo 800V may quickly reach the upper limit of current, and the power will decay rapidly. Through the actual charging performance, we can intuitively distinguish whether the vehicle is worthy of the name.

• Access to official technical data:

Finally, accurate information can be obtained through technical white papers or official publicity issued by manufacturers. If regular manufacturers do adopt 800 V full-platform design, they usually emphasize selling points such as “global 800V architecture”, “SiC inverter” and “supporting 350 kW overcharging”. On the contrary, some models may only vaguely mention “800V fast charging” and avoid details. Consumers can ask manufacturers or sellers to provide specific electrical parameters, such as battery voltage, charging module power, whether with a boost device, etc.

 

In a word, to distinguish the true and false 800 V fast charging needs to be judged comprehensively from the aspects of voltage, power, architecture, current, actual measurement and so on. The real 800 V system should be the overall scheme of battery high voltage, charging high power and vehicle high voltage components, which can bring significant improvement in charging speed and efficiency. However, those “pseudo-800V” in name are often only part of the parameters up to the standard, and there is no breakthrough in the actual experience. Through the above methods, consumers can understand 800V fast charging technology more rationally and avoid being confused by simple publicity figures.

 

7. Development status and prospects

Development status of 800V fast charging:

800V high-voltage fast charging technology is gradually becoming popular from high-end vehicles, and has become the research and development hotspot and competition focus in the field of EVs. According to incomplete statistics, more than 20 automobile brands around the world have launched or planned to launch 800V system models.

From the market launch situation, the early 800V models are mainly concentrated in the luxury high-performance field, and the price is generally more than 300000 yuan. However, 800V technology is rapidly reaching more mainstream vehicle levels. With the maturity of technology and scale effect, the cost is falling, making its application in mid-range models possible.

At the same time, charging infrastructure is also actively following up. Major charging equipment manufacturers and automobile companies have built overcharging networks to support 800V.

Future prospects:

Looking forward to the future, 800 V fast charging is expected to become one of the mainstream configurations of EVs, promoting the use experience of electric vehicles to further approach or even surpass fuel vehicles.

On the one hand, technology will continue to evolve. For example, the exploration of higher voltage levels has begun, with research projects focusing on electrical systems for electric vehicles at 1200 V and even 1500 V. The higher voltage means that the potential upper limit of charging power is further increased, and the charging time is expected to be compressed to the “minute level”. Of course, this requires breakthroughs in batteries, materials, safety and other aspects.

On the other hand, the cost will be gradually reduced. With the expansion of silicon carbide device production capacity and the maturity of technology, its price is declining year by year, and the cost disadvantage of 800V system will be weakened. At that time, 800V technology is expected to be applied in more economical vehicles to achieve real popularization.

In addition, the popularity of 800 V fast charging will also drive the upgrading of the industrial chain.

From upstream battery materials and power semiconductors to downstream charging equipment and power grid transformation, new demand and growth points will be generated due to 800V technology. For example, high-rate battery materials, high-voltage electronic components, high-power charging modules and other fields will usher in technological innovation and market expansion. It can be predicted that 800 V fast charging will become one of the important driving forces of the electric vehicle industry in the next few years.

It should be noted that with the rapid development of 800V technology, there are also some challenges, such as the unification of standards, safety standards, power grid load and other issues, which need to be solved by all parties in the industry. But generally speaking, 800V high-voltage fast charging represents the development direction of electric vehicle energy supplement technology, and its prospects are very broad. With the maturity of technology and the improvement of infrastructure, we have reason to believe that in the near future, electric vehicle users will completely bid farewell to “charging anxiety” and enjoy the experience of energy replenishment as fast as refueling.