The high-power DC charging Pile is coming

On September 13, the Ministry of Industry and Information Technology announced that GB/T 20234.1-2023 “Connecting Devices for Conductive Charging of Electric Vehicles Part 1: General Purpose” was recently proposed by the Ministry of Industry and Information Technology and under the jurisdiction of the National Technical Committee for Automotive Standardization. Requirements” and GB/T 20234.3-2023 “Connecting Devices for Conductive Charging of Electric Vehicles Part 3: DC Charging Interface” two recommended national standards were officially released.

While following my country’s current DC charging interface technical solutions and ensuring universal compatibility of new and old charging interfaces, the new standard increases the maximum charging current from 250 amps to 800 amps and the charging power to 800 kw, and adds active cooling, temperature monitoring and other related features. Technical requirements, optimization and improvement of test methods for mechanical properties, locking devices, service life, etc.

The Ministry of Industry and Information Technology pointed out that charging standards are the basis for ensuring the interconnection between electric vehicles and charging facilities as well as safe and reliable charging. In recent years, as the driving range of electric vehicles increases and the charging rate of power batteries increases, consumers have an increasingly strong demand for vehicles to quickly replenish electric energy. New technologies, new business formats, and new demands represented by “high-power DC charging” continue to Emerging, it has become a general consensus in the industry to speed up the revision and improvement of the original standards related to charging interfaces.

According to the development of electric vehicle charging technology and the demand for rapid recharge, the Ministry of Industry and Information Technology organized the National Automotive Standardization Technical Committee to complete the revision of two recommended national standards, achieving a new upgrade to the original 2015 version of the national standard scheme (commonly known as the “2015 +” standard), which is conducive to further improving the environmental adaptability, safety and reliability of conductive charging connection devices, and at the same time meeting the actual needs of DC low-power and high-power charging.

In the next step, the Ministry of Industry and Information Technology will organize relevant units to carry out in-depth publicity, promotion and implementation of the two national standards, promote the promotion and application of high-power DC charging and other technologies, and create a high-quality development environment for the new energy vehicle industry and charging facility industry. Good environment. Slow charging has always been a core pain point in the electric vehicle industry.

According to a report by Soochow Securities, the average theoretical charging rate of hot-selling models that support fast charging in 2021 is about 1C (C represents the charging rate of the battery system. In layman’s terms, 1C charging can fully charge the battery system in 60 minutes) , that is, it takes about 30 minutes to charge to achieve SOC 30%-80%, and the battery life is about 219km (NEDC standard).

In practice, most pure electric vehicles require 40-50 minutes of charging to achieve SOC 30%-80% and can travel about 150-200km. If the time to enter and leave the charging station (about 10 minutes) is included, a pure electric vehicle that takes about 1 hour to charge can only drive on the highway for about more than 1 hour.

The promotion and application of technologies such as high-power DC charging will require further upgrading of the charging network in the future. The Ministry of Science and Technology previously introduced that my country has now built a charging facility network with the largest number of charging equipment and the largest coverage area. Most of the new public charging facilities are mainly DC fast charging equipment with 120kW or above. 7kW AC slow charging piles have become standard in the private sector. The application of DC fast charging has basically been popularized in the field of special vehicles. Public charging facilities have cloud platform networking for real-time monitoring. capabilities, APP pile finding and online payment have been widely used, and new technologies such as high-power charging, low-power DC charging, automatic charging connection and orderly charging are gradually being industrialized.

In the future, the Ministry of Science and Technology will focus on key technologies and equipment for efficient collaborative charging and swapping, such as key technologies for vehicle pile cloud interconnection, charging facility planning methods and orderly charging management technologies, key technologies for high-power wireless charging, and key technologies for rapid replacement of power batteries. Strengthen scientific and technological research.

On the other hand, high-power DC charging places higher requirements on the performance of power batteries, the key components of electric vehicles.

According to the analysis of Soochow Securities, first of all, increasing the charging rate of the battery is contrary to the principle of increasing energy density, because high rate requires smaller particles of positive and negative electrode materials of the battery, and high energy density requires larger particles of positive and negative electrode materials.

Secondly, high-rate charging in a high-power state will bring more serious lithium deposition side reactions and heat generation effects to the battery, resulting in reduced battery safety.

Among them, the battery negative electrode material is the main limiting factor for fast charging. This is because the negative electrode graphite is made of graphene sheets, and lithium ions enter the sheet through the edges. Therefore, during the fast charging process, the negative electrode quickly reaches the limit of its ability to absorb ions, and lithium ions begin to form solid metal lithium on the top of the graphite particles, that is, generation Lithium precipitation side reaction. Lithium precipitation will reduce the effective area of the negative electrode for lithium ions to be embedded. On the one hand, it reduces the battery capacity, increases internal resistance, and shortens the lifespan. On the other hand, interface crystals grow and pierce the separator, affecting safety.

Professor Wu Ningning and others from Shanghai Handwe Industry Co., Ltd. have also previously written that in order to improve the fast charging capability of power batteries, it is necessary to increase the migration speed of lithium ions in the battery cathode material and speed up the embedding of lithium ions in the anode material. Improve the ionic conductivity of the electrolyte, choose a fast-charging separator, improve the ionic and electronic conductivity of the electrode, and choose an appropriate charging strategy.

However, what consumers can look forward to is that since last year, domestic battery companies have begun to develop and deploy fast-charging batteries. In August this year, the leading CATL released the 4C Shenxing superchargeable battery based on the positive lithium iron phosphate system (4C means that the battery can be fully charged in a quarter of an hour), which can achieve “10 minutes of charging and a range of 400 kw” Super fast charging speed. Under normal temperature, the battery can be charged to 80% SOC in 10 minutes. At the same time, CATL uses cell temperature control technology on the system platform, which can quickly heat to the optimal operating temperature range in low-temperature environments. Even in a low-temperature environment of -10°C, it can be charged to 80% in 30 minutes, and even in low-temperature deficits Zero-hundred-hundred-speed acceleration does not decay in the electrical state.

According to CATL, Shenxing supercharged batteries will be mass-produced within this year and will be the first to be used in Avita models.

 

CATL’s 4C Kirin fast-charging battery based on ternary lithium cathode material has also launched the ideal pure electric model this year, and recently launched the extremely krypton luxury hunting supercar 001FR.

In addition to Ningde Times, among other domestic battery companies, China New Aviation has laid out two routes, square and large cylindrical, in the field of 800V high-voltage fast charging. Square batteries support 4C fast charging, and large cylindrical batteries support 6C fast charging. Regarding the prismatic battery solution, China Innovation Aviation provides Xpeng G9 with a new generation of fast-charging lithium iron batteries and medium-nickel high-voltage ternary batteries developed based on an 800V high-voltage platform, which can achieve SOC from 10% to 80% in 20 minutes.

Honeycomb Energy released the Dragon Scale Battery in 2022. The battery is compatible with full chemical system solutions such as iron-lithium, ternary, and cobalt-free. It covers 1.6C-6C fast charging systems and can be installed on A00-D-class series models. The model is expected to be put into mass production in the fourth quarter of 2023.

Yiwei Lithium Energy will release a large cylindrical battery π system in 2023. The battery’s “π” cooling technology can solve the problem of fast charging and heating of batteries. Its 46 series large cylindrical batteries are expected to be mass-produced and delivered in the third quarter of 2023.

In August this year, Sunwanda Company also told investors that the “flash charge” battery currently launched by the company for the BEV market can be adapted to 800V high-voltage and 400V normal-voltage systems. Super fast charging 4C battery products have achieved mass production in the first quarter. The development of 4C-6C “flash charging” batteries is progressing smoothly, and the whole scenario can achieve a battery life of 400 kw in 10 minutes.