"This release is beyond the past automotive products. Is a revolutionary step for sustainable transportation." In July 2013, held in New York of the BMW group's first production type of pure electric vehicles "BMW i3" on the launch of the BMW group chairman Norbert Reithofer (Norbert Reithofer) is introduced to the audience enthusiastically with this product.
The biggest feature of i3 based framework using carbon fiber reinforced plastics (CFRP), realized the stunning lightweight.
CFRP has not only high strength and light weight than iron half, 30% lighter than aluminium, would greatly improve fuel efficiency.Is essential to realize low carbon society environmental protection material.In consume a large amount of fuel on the plane has been widely used.
In the field of automobile, although CFRP has also on the part of senior sports car use, but comprehensive application in the production car's main component was the first time.
The price reduce the single digits
Pure electric vehicles because of the need to carry large capacity battery, so the weight about 200 kg heavier than gasoline vehicles.And through the frame adopts CFRP, chassis change for aluminum alloy, reduce the weight of car body is about 350 kg, after offset light about 150 kg.Reduce sharply because the upper body, vehicle's center of gravity down, also is able to improve driving performance.
Consumer awareness of i3 is very high, in Europe, i3 listed in November 2013, order quantity has reached more than 10000 vehicles.In Japan have been listed in April.The number of allegedly hopes to test-drive broke through 10000.
I3 reason for concern is not only a performance.There is a big factor is low to the suggested retail price of 4.99 million yen (tax included).With high-grade car level, for ordinary consumers can accept the price., Japan's new energy industrial technology development organization (NEDO) electronics, material, nanometer technology director sato long line cannot hide surprise: "compared with the past fully adopt carbon fiber car, a cheaper digits. Is incredible".
Manufacture of carbon fiber, heating to use much electricity.BMW use of hydropower and wind power generation, reduces the manufacturing process of CO2."The i3" through framework on the basis of using the carbon fiber reinforced plastics, chassis adopts aluminium alloy, successfully reduced about 350 kg.In order to realize the "carbon fiber car" goods into a target, and automobile companies all over the world began a pitched battle.Toyota 2010 sports car "lexus" is the first Japanese car full of CFRP to make car body, became the focus of attention.But its price is the highest 37.5 million yen hit a Japanese car.Because the order are handmade production mode, so the cost limited compression.
BMW by developing a variety of technology to improve production efficiency, and finally the CFRP successfully applied to the production car.
Carbon fiber is such as propylene fiber "steaming roast" carbonized under anaerobic condition.The carbon fiber in the plane arrangement, or weaving and reinforced with resin, became the CFRP.
Aircraft such as the use of CFRP in molding, in special kettle heating pressure, make the component of hardening.To do so while it is possible to obtain high strength, but forming, need a certain number of hours and high cost.I3 using CFRP using the new technology of no pressure heating - RTM (resin transfer molding) : the preforming of carbon fiber cloth into the mold, high pressure injection of resin, fiber and resin combination, can be formed within 10 minutes.
And also developed the will of gluing of CFRP to shape goods adhesives, bonding time reduced to 1/10 of the past, bonding process also USES automated robot.Through constructing production system, greatly reduce the cost, crossed the threshold of the 1000 yen per kg /
Carbon fiber is also Japan's family.Japan fiber industry strength, focus on long-term development and sustained investment in research and development of fiber enterprises force, Europe and the United States, Japan, holds 70% of the world's share.BMW's carbon fiber strand supplier is Japan's mitsubishi rayon.As a real environmental protection material of carbon fiber is from the world's attention, carbon fiber competition is stage has begun in Japan.
On a par with car in another carbon fiber main battlefield - the plane field, toray airbus and Boeing, teijin and France respectively, launched a battle for supremacy.
In 1971, toray first to start commercial production in the global carbon fiber, now share the top of the world.In 1975, Boeing pioneered in the carbon fiber on the part of the wing.
, toray continue to constantly improve quality, increase the tensile strength (fracture) difficult to nearly 2 times, tensile modulus of elasticity deformation (easy) to nearly three times, meet the needs of a number of purposes.Its technical strength acclaimed, medium-sized passenger plane into service in 2011, the most advanced "Boeing 787" on, CFRP has accounted for five of the body weight.
Teijin has been for a long time for airbus to double airliner A380 "of the world's largest supply of carbon fiber and carbon fiber precursor fiber cloth etc.And, will also be in the form of artifacts, for the first time to book into service during the year of a new generation of medium-sized passenger plane "A350WB" test aircraft supply main structural material such as the body and wings, the relationship is steadily rising.
In the future, the demand of carbon fiber is expected to expand at an annual rate of more than 15%.Five years later, is expected to market will expand to more than 2 times today.Toray ACM technology minister oda cut letter said: "(carbon fiber) is leading the green innovation, and shoulder the future of the company products".
Carbon fiber to reach in society and the degree of iron and aluminum, we've got a lot of to solve the issue.One of the more important is cost and formability.If, for example, to be applied to the popularity of cheaper than BMW i3 price production car, after forming, under the condition of CFRP need to control the price of around 1000 yen per kg /.And the current price is several times to dozens times.
So, by toray, mitsubishi, Japan spinning, azusa seiko, team of the university of Tokyo and other challenges the NEDO project - volume production at low prices "carbon fiber strengthening hot plasticity resin (CFRTP)", and developed in February 2013.
Circulate on the market of CFRP is most used heating can harden thermosetting resin such as epoxy resin.Although strength is good, this kind of resin had shortcomings and so on processing problems.
Through the use of heating will soften and thermal plasticity of the polypropylene resin, is expected to be in equal to iron stamping molding within 1 minute.Because you can use the mould processing into the shape of a complex, therefore can be used to manufacture a variety of artifacts.Its biggest drawback, insufficient strength, through the implementation of the carbon fiber special treatment combined with solid resin, overcome.
Polypropylene resin is more cheaper than epoxy resin.Mentioned sato director said: "if can reduce the price of carbon fiber, by cheap resin raw materials and processing fee of compression, carbon fiber could be widely used in the production car".
According to the project estimation, ordinary passenger cars if change about 60% of the iron artifacts to CFRTP, car body can reduce about 30%.Gasoline consumption can also be reduced by 22.5%.
In the future, will continue to study joint technology of carbon fiber and other materials, such as after car companies into estimation, is expected to achieve commercialization after 2020.