Starting from traditional fuel vehicles, the lightweight of automobiles is one of the most effective measures to reduce fuel consumption and carbon emissions, which is a topic that cannot be avoided since the birth of automobiles, and it is also a topic that "Jufeng Plastics" will take out every once in a short period of time. In the past two or three years, the penetration rate of new energy vehicles in China has become higher and higher, and the lightweight of such vehicles has also attracted more and more attention. As the key system of the car, the body (including windows, doors, cockpit, passenger compartment, engine compartment and luggage compartment, etc.) accounts for almost 1 3 of the weight of the whole vehicle, which is an important part of the lightweight of the car. Today, from the perspective of the plastics industry, let's talk about the lightweight of new energy vehicle bodies.
Compared with oil vehicles, electric vehicles have canceled the engine and some additional systems, and added the "three electric systems (battery, motor, electronic control)", which is heavier, which has an adverse impact on the power consumption, mileage, power, reliability, braking and durability of the vehicle, so new energy vehicles are more urgent than fuel vehicles to be lightweight. Studies have shown that for every 100kg reduction in the mass of electric vehicles, the cruising range can be increased by 15-20km, and the braking distance can be shortened by 2-7m at low speed and 1-2m at high speed. Automobile lightweight technology has become one of the important directions for the development of new energy at home and abroad, and it is also the basic technology for the development of new energy vehicles.
Body lightweighting is not the best goal of pursuing the lightest weight, nor is it the same as "cutting corners", but a balance between collision safety, platform expansion, handling stability, strength and durability, and NVH (noise, vibration, harshness). There are three main ways to realize the lightweight of automobiles:
First, the structure is lightweightOptimize the body structure to make parts thin-walled, hollow-out, miniaturized or compounded. In view of the trend of thin-walling, the requirements for the injection molding machine for the production of thin-walled plastic auto parts are fast speed and high precision, and high-speed and low-pressure injection molding is generally used, which has high requirements for the overall stability of the machine.
Second, the material lightweight:The use of lightweight new materials is the most direct way to achieve vehicle weight reduction. I still remember that two years ago, a domestic automobile celebrity once said - before 2035, all kinds of materials and dosages of automobiles will be equally divided, ordinary steel, high-strength steel, polymer, aluminum alloy, magnesium alloy will reach 20% of the application, this is the great revolution of the automotive materials industry.
Polymer materials (including plastics, rubber) and thermoplastic composites have low density and good performance, which is an effective way to reduce vehicle weight. The automotive industry has made material lightweight the top priority of sustainable development, which is inseparable from the joint exploration and innovation of the upstream and downstream of the industrial chain such as raw material suppliers, modification factories and injection molding machine factories.
It has become an important trend in the new energy vehicle industry to replace metal with composite system lightweight materials (plastic instead of steel) in body structural parts such as tailgate panel components, front-end modules, door modules, and seat structures. Chery Automobile and its first-tier supplier Wuhu Hengxin have achieved a 40% reduction in the internal structure of the tailgate panel of the EQ1 electric vehicle (see photo below), thanks to the use of SABIC's long glass-filled polypropylene (LGFPP) resin material Stamax, a low-density material that can achieve the required stiffness while reducing the weight of the inner tailgate panel compared to steel.
In addition to "replacing steel with plastic", it is not uncommon to replace engineering plastics with modified PP and other materials, which is subverting the traditional field of automotive engineering plastics. Polypropylene PP has a low density in automotive plastics, which is one of the lightest varieties and the largest proportion of automotive plastics. Modified plastics have the dual advantages of low density and high performance, compared with engineering plastics, easy to process, easy to improve and cost-effective, as well as excellent chemical corrosion resistance and good mechanical properties, which can help manufacturers ensure the quality of finished products, ride safety while reducing costs and energy saving. The low linear thermal expansion coefficient modified PP products developed by Kingfa Technology Co., Ltd. have a linear expansion coefficient equivalent to that of metal, excellent dimensional stability, good sprayability and adhesive properties, and can meet the requirements of vehicle lightweight.
3. Manufacturing lightweight:Advanced manufacturing processes are applied, mainly including molding technology and joining technology. At present, there are a variety of lightweight manufacturing processes to choose from in the design and development of plastic parts, these processes generally have the characteristics of low cost, high efficiency, excellent product quality, etc., the typical is the micro-foaming process, micro-foaming is divided into physical foaming and chemical foaming, and it is widely used in the automotive industry is physical foaming, that is, supercritical nitrogen (N2), through the shearing of the screw, is evenly mixed into the molten resin, and then injected into the mold cavity to produce bubbles.
Cellmould technology (see figure below) is a micro-foaming technology independently developed by Witamann, with several options such as standard foaming, variable mold temperature foaming, sandwich injection foaming, etc., which can produce very lightweight, high-stiffness, shrinkage-free foaming parts, and is designed to produce thick-walled and thin-walled structural foamed parts with fine and uniform bubble cells and lightweight characteristics.
The OIHM** injection hot pressing technology in the CIML series carbon fiber product intelligent molding production line developed by Bole Plastics Machinery integrates equipment, technology, and material formulation, and "combines the "mixing granulation" and "injection molding" processes into one, so that the direct injection molding of long fiber reinforced composites (** mixing injection molding) saves 10 processes compared with the traditional process, and the tensile, bending and notched impact resistance are increased by more than 20%. Reducing the weight of accessories by more than 65% and effectively extending the cruising range of the car can be said to have created a powerful tool for automobile lightweight technology.
To sum up, the comprehensive use of vehicle structural optimization design, lightweight materials and advanced manufacturing technology is an important way to effectively realize the lightweight of the vehicleUse the right materials, in the right way, in the right place.
Lightweight technology is of great significance to the sustainable development of the automobile industry, which is not only related to the energy saving, emission reduction, low carbon, environmental protection, safety, cost and many other aspects of the vehicle, but also has a profound impact on the energy, natural resources and environment of our world. Lightweight is the goal pursued by new energy vehicles, and the plastics industry can show its ability and power in this regard