What are the charging problems of electric vehicles: fast charging.
Tesla and the new brand pure electric vehicle launched this year are equipped with fast charging technology. At present, the fast charging technology of electric vehicles can charge the battery to 80% in a few minutes, which is obviously 7-8 hours (or even longer) faster than slow charging.
The policy also spares no effort to support fast charging technology. For example, in the new financial subsidy scheme officially implemented on June 5438+1 October1,the subsidy amount for new fast-charging new energy buses is 3,000 yuan per kWh, which is 67% higher than that for non-fast-charging buses.
What are the charging problems of electric vehicles: mainstream battery technology
Driven by policies and markets, battery companies are also actively promoting the development of fast charging technology. At present, there are three mainstream fast-charging power battery technologies:
The first lithium titanate battery with ternary material as the positive electrode and lithium titanate as the negative electrode has been recognized by the market for its fast charging rate. Taking Zhuhai Yinlong lithium titanate battery as an example, it can be fully charged in 6- 15 minutes, but the defects of high cost and low energy density are also obvious.
The second kind of multi-element composite fast charging battery takes the mixed system of ternary material and lithium manganate as the positive electrode and porous composite carbon as the negative electrode. Because the specific surface area of porous composite carbon is 20 times higher than that of traditional graphite, the fast charging performance will be further improved. But there are also some problems such as short cycle life and low safety factor.
The third lithium ferrous phosphate fast-charging battery has been optimized in mature systems. The anode and cathode are made of materials with small particle size and large specific surface area to meet the requirements of rapid intercalation and deintercalation of lithium ions, reduce the viscosity of electrolyte and improve the fluidity of lithium ions; The material cost is relatively low. Combined with mature technology and stable product performance, Ferrous lithium phosphate fast-charging battery has great development potential.
Although the application of fast-charging lithium-ion power battery is still in the small-scale use stage, the fast-charging mode has brought great convenience to the operation of pure electric buses, initially shortened the configuration capacity of the battery pack and reduced the cost. Secondly, with the shortening of battery volume and weight, the air utilization rate and safety factor of the car are improved, and the fast charging also greatly reduces the charging time and increases the operating income.
In the first three batches of "Catalogue of Promotion and Application of New Energy Vehicles", there are nearly 40 buses with fast charging rate above 5C. At present, fast-charging power battery is the key application of new energy buses, especially the successful application of bus system, which has been verified by the market and has formed scale effect through development and change.
Therefore, although the proportion of high-speed fast charging technology used in passenger car and special purpose vehicle market is still very limited, the extension trend is very clear, and the future potential and promotion space are huge. Therefore, companies that develop fast charging technology are increasingly favored by original equipment manufacturers.
What are the charging problems of electric vehicles?
Take the Catalogue of Promotion and Application of New Energy Vehicles (Eighth Batch) issued by the Ministry of Industry and Information Technology in early September as an example. There are 13 fast-charging buses in the Catalogue, and the fast-charging rate of 9 products is above 5C, and the highest can reach 5.27C Compared with the eighth issue of the Catalogue, the number of 1 1 fast-charging buses has increased significantly year-on-year, and the fast-charging level has also improved significantly.
Not long ago, it goes without saying that Takahiro Baxiang, CEO of Honda, is developing a new fast charging system, with an estimated charging time of 65,438+05 minutes and a battery life of 242 kilometers. Facing the problem of difficult charging, Honda is also developing wireless charging technology for cars, which can shorten the number of times drivers charge well and make driving electric vehicles more convenient and enjoyable.
The new electric vehicle being developed by Toyota will use all-solid-state batteries, which can be charged in just a few minutes, so the charging process is similar to the current refueling time. Toyota believes that in the new generation of batteries, solid-state batteries are the most suitable for electric vehicles. At present, Toyota and Japanese research institutions are developing. The key is the standardized production process of solid-state batteries, which is expected to be commercialized in early 2020.
Toshiba recently announced that it has developed a new generation of lithium batteries for electric vehicles, which can be quickly charged in just 6 minutes.
According to reports, unlike most lithium batteries, which use graphite as the cathode material, this lithium battery uses titanium niobium oxide as the cathode material, which has the characteristics of high energy density and ultra-fast charging. The traditional lithium battery for electric vehicles can only charge about 80% of the electricity in 30 minutes, while new lithium battery can charge 90% of the electricity in 6 minutes. Toshiba's test electric car finally ran about 320 kilometers after charging for 6 minutes.
After 5000 times of charge and discharge, the lithium battery can still maintain more than 90% of the battery capacity, and can still be charged quickly at the low temperature of-10 degrees Celsius. The representative of Toshiba has made a new generation of lithium battery samples with a capacity of 50 amps/hour and the size of a palm, and plans to improve them, striving to launch a formal product in 20 19.
Daimler Truck also recently invested in Storedotcompany, an Israeli battery technology startup (US$ 60 million), and devoted itself to the research and development of fast battery charging technology for electric vehicles, making its charging time (about 5 minutes) almost the same as that of diesel locomotives. At the beginning of this year, the company introduced a battery sample, which can fully charge an electric car in five minutes, making its cruising range reach more than 300 miles.
It should be pointed out that no matter how to realize high-power charging, it will basically bring severe challenges to the high-voltage system of electric vehicles. Bai Jian, senior technical manager of Beijing New Energy Automobile Co., Ltd., briefly introduced that high-power charging technology should improve PEU (power regulating unit), such as: IGBT (insulated gate bipolar transistor) in MCU (motor regulating unit) should be re-selected, transformer (vehicle charger) on the output side of OBC should be adjusted, and components such as capacitors and diodes should be used with withstand voltage above 900V; As far as DC/DC is concerned, it is also necessary to adjust the input side transformer; In terms of power battery system (BMS) and vehicle regulation system (VCU), the emphasis is on the addition of temperature sensor, the adjustment and design of regulation strategy and guarantee strategy. In addition, the high-voltage wiring harness should also be optimized.
However, no one thinks that such fast charging will cause more loss of automobile batteries. I think whether it is DC fast charging or AC slow charging, as long as the charging upper limit is adjusted to 1c, that is, the battery is fully charged for more than one hour, it will not affect the battery life.
Today, the introduction of automobile system ends here. The above is a brief introduction to the charging system of electric vehicles. Electric vehicle charging has always been a crucial issue in everyone's mind. More and more people choose new energy vehicles, so basically everything is getting more and more perfect, so new energy vehicles are a good choice for you. If you want to know more about the car series, please pay attention.
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