In the world of electric vehicles, range anxiety and energy supply anxiety have always been tied to the hearts of users, and the latter anxiety is increasing day by day with the continuous increase in the number of electric vehicles and the increase in battery capacity.
On March 1, Li Auto's first pure electric model, Ideal MEGA, was officially launched, becoming the world's fastest mass-produced electric vehicle with a performance index of "500 kilometers in 12 minutes of charging", and also has a long range of more than 700 kilometers.
Ideal car.
As a large MPV, the Ideal MEGA achieves the fastest energy replenishment speed and long battery life, which is inseparable from the 800V high-voltage platform and the blessing of the CATL Kirin 5C battery. According to the official introduction, the ideal MEGA adopts an 800V high-voltage platform and is equipped with a CATL Kirin 5C battery, with a battery pack capacity of 102At 7kWh, the CLTC cruising range reaches 710km, and the cycle life is increased by more than 50% compared with the mainstream 2C ternary cells.
It should be pointed out that before the ideal MEGA, CATL Kirin batteries have been installed in a number of popular models, such as Geely's ZEEKR 001, ZEEKR 009, ZEEKR 001FR, Nezha S and Wenjie M9. So, compared with several other models that have been equipped with Kirin batteries, what is special about MEGA Kirin batteries? How to take into account the high mileage of the MEGA Kirin battery while achieving high rate charging? For the battery thermal runaway problem that users are extremely concerned about, what aspects of the layout of MEGA Kirin battery has been made?
In response to the above problems, Liu Zhimin, senior director of Li Auto Power Battery, and Gao Huan, CTO of CATL's domestic passenger car division, dismantled them one by one in an interview with **, including Gasgoo.
The fastest power battery
In June 2022, CATL released the Kirin battery based on the third-generation CTP (Cell to Pack) architecture for the first time, compared with the previous two generations of CTP technology, the Kirin battery completely canceled the module form design, and relied on the world's first multi-functional elastic interlayer and improved water cooling plate design to achieve a comprehensive improvement in battery life, fast charging, safety, life, efficiency and low-temperature performance.
With ternary cells, the energy density of Kirin batteries can reach 255Wh kg, and the energy density of lithium iron phosphate battery cells can reach 160Wh kg, and the power of Kirin battery packs can be increased by 13% compared with 4680 large cylindrical battery systems under the same chemical system and the same battery pack size. In addition, in terms of volume utilization, Kirin batteries exceeded 72%, and the integration of battery packs was the highest in the world at that time.
In the first quarter of 2023, Kirin batteries will be officially mass-produced, and ZEEKR 009 will be used for the first time. In May of the same year, the ZEEKR 001 1,000-mile range WE version equipped with CATL Kirin batteries was delivered, with a battery pack capacity of 140kWh, making the ZEEKR 001WE version the world's first mass-produced model with a pure electric range of more than 1,000 kilometers equipped with Kirin batteries.
When asked what is the uniqueness of the Kirin battery equipped with the Ideal MEGA, Gao Huan, CTO of CATL's domestic passenger car division, said: "The Kirin 5C battery of the Ideal CATL is a battery jointly developed by us and Li Auto for the MEGA, which achieves a range of 500 kilometers in 12 minutes of charging - it is also the fastest battery in the world at present, and can also achieve a long range of more than 700 kilometers, combined with the ideal thermal management control algorithm and the 5C super charging network. It can achieve a wide temperature range, and can achieve ultra-fast energy replenishment in winter and summer. ”
He also pointed out that the Kirin battery is customized to serve the differentiated needs of the whole vehicle, and according to different performance, the Kirin battery is divided into three technical routes: super fast charging, ultra-high power, and ultra-long battery life.
For example, the ZEEKR 001we version has achieved an ultra-long range of 1,000 kilometers, which is the world's only large-scale mass-produced Kirin ultra-long battery model. In addition, the ZEEKR 001 FR version of zero hundred acceleration to achieve two seconds level, the car is equipped with the Kirin ultra-long feature is particularly strong discharge capacity, can reach the megawatt level of discharge, two or three seconds can be discharged to the second degree.
The Kirin brand is to provide customized services for the differentiated needs of the whole vehicle, to achieve accurate service, to give it super performance, just talked about 12 minutes 500 kilometers super fast charging, super power 2The 02-second 000 acceleration and the super endurance of 1032 kilometers are all very eye-catching data. In the future, we will supplement and improve the product matrix of Kirin batteries according to the attribute positioning of the model and the needs of users of the main engine factory. Gao Huan said.
How to balance performance between high-rate charging and high mileage?
With high rate charging and high mileage, as a large MPV, how can the ideal Mega Kirin 5C battery have both fish and bear's paws?
In this regard, Gao Huan said that the power consumption of the ideal mega is 159kWh 100km, so the battery is very large and has more than 100 kWh, and it is necessary to ensure a range of more than 700km while achieving 5C super fast charging, which has two breakthroughs at the core level.
First of all, at the cell level, the ideal MEGA Kirin 5C battery optimizes the chemical system, including the positive electrode, negative electrode, separator, electrolyte, etc., and makes some optimizations on the physical gradient of the cell electrode.
Secondly, in terms of the entire structural level, if the integration efficiency is too low and the power cannot be loaded according to the previous traditional level of battery cells to modules, modules and then packs, Kirin batteries pass CTP3The 0 architecture adopts double large-sided water cooling plates, which not only ensures its heat dissipation area, but also improves the integration efficiency of the entire battery pack.
Of course, there are many challenges, such as the internal resistance of the battery cell to achieve 0Below 3m, this is an industry problem. Kirin battery achieves internal resistance of 0Within 3m, it has gone through 100+ rounds of verification and tens of thousands of test cells, and finally achieved through a series of measures such as the optimization of cathode materials and their interfaces, low viscosity and high conductivity electrolyte, and high current carrying design of cell mechanical structure.
Gao Huan said frankly that in fact, as early as 2017, CATL was researching super fast charging technology above level 4C, but the technology maturity was not enough at that time, and the energy density of the battery had to be sacrificed to achieve fast charging, such as the original range of 400 kilometers, and the energy density was sacrificed in order to achieve the ability of fast charging, which became more than 200 kilometers. "After so many years of research, including in-depth research with the Li Auto team, and mutual inspiration, we have made a fundamental breakthrough in the past two years. ”
Li Auto decided to develop a solution for super-rechargeable batteries from 2018, when the industry did not have a complete super-rechargeable battery technology route, and at that time found many domestic and foreign battery companies to do joint conceptual technical solutions, including doing some advanced technical discussions, which also went through two years, and finally firmly chose CATL to jointly develop with us, and finally had the application performance of the ideal-CATL Kirin 5C battery on MEGA that we see today. Looking back on the development process of the ideal MEGA Kirin battery, Liu Zhimin, senior director of the power battery of the ideal car, said with emotion.
Of course, this is inseparable from the large investment of human and material resources by the teams of both sides. According to Liu Zhimin, in the end, when doing the project review, it was found that more than 1,000 people were invested in the entire project cycle, which is 5-8 times the investment of ordinary battery development projects, and after a three-year development cycle, it is at least twice the time of the normal project cycle, and the development cycle of a battery is about one and a half years.
How to ensure the safety of the fastest electric train?
As the first model of Li Auto to switch to the pure electric market, and it is also the electric vehicle with the fastest energy replenishment speed at present, how to maintain the bottom line of safety is the focus of all users. In this regard, Liu Zhimin focused on the safety design made by Ideal MEGA for the thermal runaway problem of power battery.
For power batteries, the ultimate safety must be our goal, so Li Auto has defined the industry's highest thermal runaway safety standard at the very beginning. Liu Zhimin pointed out that the standard of thermal runaway of the ideal car is to heat the entire battery pack to 50 in the test, and it is to trigger one of the cells when the water cooling system is not working, and the whole package is not allowed to see open flames, which is much higher than the industry standard. "In fact, it is difficult for the battery to reach 50 degrees during use, but we still use this very extreme working condition to define the safety standard, and the test and verification are all passed. ”
Specific to the safety features of the MEGA Kirin 5C battery, it mainly involves the following links:
In the design process of the battery, whether it is the safety design of the battery cell itself, or the protection of the pack, or the insulation (including heat conductivity) in the battery pack, all the processes are positive disassembly, because of the potential risks that may be brought by overcharging, MEGA has made a safe redundancy design, which is guaranteed from the perspective of safety genes.
In the manufacturing process, Li Auto's batteries are produced in CATL's "lighthouse factory", which represents the highest level of power battery manufacturing in the entire industry, and all process data will be stored in the system for ten years and can be traced. "It's not enough to trace the data, there are also a lot of AI algorithms, we not only look at the outliers in the battery manufacturing process, but also look at the battery trends produced, although it is not above the safe boundary now, but it has a trend, and we will pick it out. ”
When the battery is delivered to the user, whether it is at the vehicle end, at the charging station, or in the cloud, Li Auto has a very complete three-in-one safety monitoring system, and the three lines of defense do relevant protection for safety.
Based on the joint efforts of both parties and CATL's R&D capabilities, Liu Zhimin is full of confidence in the future performance of the MEGA Kirin 5C battery.
According to reports, since its establishment in 2015, from the first generation of the product Ideal ONE, to the second generation of L9, L8, L7, Li Auto has been doing joint development with CATL throughout the whole process, and most of the 680,000 cars that have been delivered are by CATL. At present, the Li Auto brand holds a record in the entire industry: none of the vehicles delivered to users are due to the battery itself**, which is very rare. ”