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Electric car battery and motor assembly it just so simple

Opportune Chinese electric car enterprises to reap, China seems to have become the center of the world's electric car industry -

In fact, in Germany, if your unit does not provide charging pile, you may need to buy yourself a charging pile on the doorstep. However, we always discuss why so many good German car firms are not made out Tesla, and now look at the reasons are not hard to find.

Lienkamp Professor Technical University of Munich published a free and open society to a new book in 2014, "Status of electrical mobility 2014" in said: "While electric cars have all sorts of flaws, but I have never seen one already has an electric driver of the car, back toward the embrace of conventional cars. even one of the most common electric car to bring your driving pleasure, but also a gasoline car can not match. "such a car can really let the owners do not back Touhui traditional car embrace it?

As we all know, the core of electric vehicles is the battery.

An ordinary electric car, a standard test in Europe, about one hundred kilometers energy consumption of 17kWh, or 17 kWh. Dr. ThomasPesce studied the compact car consumption under optimal configuration, without regard to cost, the use of existing technologies that can be purchased to obtain the best results for one hundred kilometers energy consumption of 15kWh slightly. This means that in the short term by trying to optimize the efficiency of the car itself to reduce energy consumption, even without considering the additional costs brought about by the energy saving effect is relatively small.

Natesila 85kWh battery pack, for example, with a nominal distance of 500km, if energy consumption through various efforts to reduce 15kWh / 100km, the distance traveled can be raised to 560km. So, yes, the car's endurance and capacity of the battery pack is proportional to, and the proportional coefficient is relatively fixed. Well, from this perspective, the use of higher energy density (energy per unit weight Wh / kg and the energy per unit volume Wh / L need to be considered) batteries, to enhance the performance of electric vehicles it is significant, because in the electric car , the battery occupies a large part of the total weight.

 

Various lithium-ion battery is not only the deepest expectations of everyone, is now the most widely used battery. Automotive lithium batteries are mainly used in nickel-cobalt manganese lithium battery three yuan (NCM), a nickel-cobalt-aluminum lithium batteries (NCA) and lithium iron phosphate battery (LPF).

1, nickel, cobalt and manganese lithium battery NCM three yuan

Because of the lower heat rate, relatively better stability, longer life, and 150-220Wh / kg energy density, NCM battery is used by many foreign electric vehicles.

 

2, NCA nickel-cobalt-aluminum lithium battery

Tesla used namely for this battery. High energy density, in 200-260Wh / kg, and it is expected to soon reach 300Wh / kg. The main problem is that the only one able to produce this Panasonic batteries, high prices, and security in the three worst-lithium battery, you need a high-performance thermal and battery management system.

 

3, LPF lithium iron phosphate battery electric vehicles made in China last term most used LPF batteries. The biggest drawback is that this type of battery energy density is very low, can only reach 100-120Wh / kg. In addition, LPF also has a high self-discharge rate. This is the electric car maker undesirable. LPF is widely used in the country is more like domestic manufacturers for expensive battery management and cooling system compromise --LPF battery has a very high stability and security, even with poor battery management system, it is possible to ensure stable operation and longer battery life. Another advantage of this characteristic is brought about, in part LPF battery with a high discharge power density can be improved vehicle dynamic performance. In addition, LPF battery price is relatively low, and therefore suitable for low-end domestic electric cars, low-cost strategy. But if you want as a future battery technology to develop, the need to make a question mark.

An ordinary electric car battery should be how much? Tesla is the use of thousands of batteries series-parallel battery pack or the use of a very few large battery BYD to build a battery pack? This is still a research problem, there is no an exact answer. Here only large and small battery cells constituting the respective characteristics of the battery pack.

When the battery is small, the total battery cooling area will be relatively large, it can be a reasonable thermal design of the temperature of the entire battery pack effectively control, prevent high temperature accelerated derogation battery life. Usually monomers smaller capacity battery power, the energy density will be higher. Finally, and more importantly, in general, the less energy unit cell, the vehicle security is higher. A battery from a battery pack consisting of a large number of small, even if a monomer is a problem, that does not cause much of a problem. But if a large capacity battery inside is a problem, then the security risk is much greater. Therefore, a large battery needs more protection, which further reduces the energy density of the battery pack consisting of a large battery.

However, the use of Tesla's scheme, the disadvantages are also obvious. Thousands of batteries, battery management system is extremely complex, bring additional costs should not be overlooked. Volkswagen E-Golf on the use of BMS (Battery Management System), a sub-module is able to manage 12 battery, the price is $ 17. Tesla estimates in accordance with the number of cells used, even if a lower cost BMS independent research and development, investment in Tesla BMS costs are more than $ 5,000, accounting for more than 5% of the vehicle cost. Seen in this light, and not blindly say that big bad battery. In the case of BMS price has not been significantly reduced, it should be based on the positioning of the car to determine the size of the battery pack.

An electric motor vehicles Another core technology, often become the core of the discussion, in particular the size of watermelons that Taiwan Tesla sports car performance, has a motor, it is stunning (Model S motor peak power can reach 300kW or more, the maximum torque of 600Nm, peak power is close to EMU single motor power). German auto industry researchers evaluated as follows:

Tesla uses almost nothing except conventional components (aluminum body,

asynchronous motor for propulsion, conventional chassis technology with air

suspension, ESP and a conventional brake system with electrical vacuum pump, laptop cells etc.)

Tesla used are traditional parts, aluminum body, induction motor, the traditional car and brake system and laptop batteries and so on.

The only genuine innovation lies in the technology linking up the battery

cells, which uses bonding wires that Tesla has patented, as well as battery

management system that can be flashed "over the air", meaning that the

vehicle no longer needs to drive to a workshop to receive software updates.

Tesla only genius invention, in that their handling of the battery. They use a special battery cable, and wireless networking can be directly returned to the manufacturer without the need to update the software of BMS.

In fact, the Tesla induction motor has high power density is not too new. On the first Tesla Roadster model, the parameter is used in Taiwan Tomita motor products, parameters, and announced Model S and there is not much difference. In the current study, the scholars are low-cost high-power motor design can be quickly brought into production. So when you look at this area, to avoid the myth Tesla - Tesla motors are good enough, but not good enough to let others have made out.

Among the many types of motors, the electric car is typically used mainly asynchronous motors (also known as induction motors), outside excited synchronous motors, permanent magnet synchronous motors and hybrid synchronous motor. I believe that the first three motor electric car people understand, there will be some basic concepts, low cost and high reliability asynchronous motors, permanent magnet synchronous motors high power density and efficiency, small but expensive, complex high speed control section .

Hybrid synchronous motor you may have heard less, but recently, many European motor suppliers are beginning to provide such a motor, very high power density and efficiency, strong overload capacity, but the control is not too difficult, very suitable for electric vehicles.

The motor is also not so special, and permanent magnet synchronous motors compared to the permanent magnets on the rotor in addition, it has added similar to traditional synchronous motor field winding. Such motors, permanent magnet has both of the high power density, and magnetic field can be adjusted according to the demand by the field winding, can be more easily controlled in every speed segment. Typical such as Switzerland BRUSA company's HSM1 series motor, which HSM1-10.18.22 characteristic curve in the following figure, the maximum power of 220kW, maximum torque of 460Nm, but its volume is only 24L (diameter 30 cm, length 34 cm), and weighs about 76kg. Power density and torque density and Tesla product roughly equal. Of course, prices are not cheap, coupled with the motor drive, priced at 11,000 euros.

The demand for electric vehicles, motor technology is mature enough to accumulate. Motor currently lacking is designed specifically for electric vehicles, rather than producing such motor technology. I believe that with the gradual maturation and development of the market, high power density of the motor more and more popular, the price will be more close to the people.

The demand for electric vehicles, but currently lack the motor designed for electric vehicle design. I believe that with the gradual maturation and development of the market, high power density of the motor more and more popular, the price will be more close to the people.

Research on electric vehicles need to return to nature. The nature of the electric car is safe, people could afford transportation only, rather than a mobile technology lab, not necessarily using the most advanced, most fashionable technology. Ultimately, it should be in accordance with the needs of the region, planning and design of ground gas.

The emergence of Tesla, has been to show people that the future will belong to electric vehicles. The future of the electric car is what it looks like, the future of China can occupy what position in the electric vehicle industry, but also are unknown. This is exactly where the charm of the industrial work: natural sciences and different, even inevitable result of social scientific laws are clear, but also need people through hard exploration and efforts to achieve!

(Author: TUM doctoral electric car project)

    July 31, 2015, Shandong Depuda Electric Co., Ltd. in the country SME share transfer system formally. The successful listing marks have Puda Motor has taken a substantial leap-step to the capital markets, and laid a solid foundation for the company to develop faster and better.

    Puda Motor Company was mainly engaged in electric vehicle drive development, production and sale of electrical products, and its products are widely used in small electric vehicles and other fields. The company has made compulsory certification National Car Quality Supervision and Inspection Center. In 2010 the company set up a "micro Zibo West - have Puda Motor Institute," 2012 in Zibo City Science and Technology Bureau identified as "short-distance pure electric passenger vehicles in Zibo City Electrical Engineering Technology Research Center", research and production in the motor go the forefront of the industry, the development of electric vehicles, multi-purpose motor through the results of identification of the products in Shandong Province Science and Technology Department, the leading domestic level, eight involved in the development of national standards and industry standards.