Electric-vehicle makers looking for fresh impetus are turning to thermoplastics, as these can be used to  improve the safety, performance and sustainability of the vehicles. Initial application areas for manufacturers can be found in a multitude of components ranging from battery cases to busbars, cooling lines and seals. Things become very interesting when material suppliers offer support in the form of CAE and injection molding analyses.

Thermoplastics play an important role in the batteries of electric vehicles. They help to keep battery temperatures in the optimal range for a long service life and high performance. 

16:9

Improving the Performance of Electric Vehicles with the Right Materials

Kfz-Elektronik

Elektronik

Elektromobilität

Mobilität

Polyamide

Kunststoff Werkstoffe

Thermoplaste

Technische Kunststoffe

Electric, Environmentally Friendly, Thermoplastic

The conditions in electric vehicles place high demands on the materials used. Therefore, automakers and suppliers must resort to expensive, high-performance plastics. For many applications, cost-effective alternatives are plastics whose properties have been greatly improved by means of treatment with high-energy electron beams.

Fig. 1. Crosslinked engineering plastics can be used for many different applications in electric vehicles.

Irradiation Crosslinking Replaces High-Performance Plastics with Cheaper Polymers

Strahlenvernetzung

Kunststoffverarbeitung: Verfahren

Kunststoff-Aufbereitung

Hochleistungskunststoffe

Electron Booster for Electric Vehicles

Electromobility in particular, but also many other electrical applications, are asking for ever higher demands regarding the electrical properties of thermoplastics. This raises the question of whether the polymers commonly used in this area can still meet these demands. The plastics manufacturer, Lanxess, has now investigated how suitable, for example, polyamide and polybutylene terephthalate are for use at higher voltages and temperatures.

How Suitable Are PA and PBT for High-Voltage Applications?

Polybutylenterephthalat

Leistungselektronik

Against the Current

With the change from internal combustion engines to hybrid and electric vehicles, peak operating temperatures have dropped from 135 °C to 110 °C. At the same time, the number of operating hours compared to combustion engines has increased nine-fold. This has an influence on material selection.

A Comparison of PA66 and PPA for Electric Vehicles

Elektromotoren

Antriebe

Higher Performance in Water

A focal point of the Lanxess booth at the show this year will be materials for electromobility.

The demonstrator of a near-series- production housing for electric vehicle batteries is one of the highlights at  the Lanxess booth.

Messe K-Kunststoffmesse

kunststoffe-international.com

kunststoffe.de

Demonstrator for EV Battery Housings

Due to the climate change, new fields of development and sustainability topics have come into focus along the added-value chain.

Polyamide continues to be one of the most important technical plastics in the automotive sector, where it enjoys widespread use. This not only applies for classical internal combustion vehicles, but in terms of volume will also be the case for electric vehicles.

Polyamides: Electromobility and Sustainability Boost Developments

Kunststoff-Recycling

Dual Change with Polyamides

Ascend Performance Materials will focus on electromobility and sustainability at K. The company made this announcement at a press conference in advance of the trade show.

Wide Range of PA Innovations

The transformation from the combustion to the electric engine entails several imponderabilities for the plastics industry. In part, electric drives have completely different material requirements which are becoming specifically evident with the increasing use of appropriate vehicles.

In electric vehicles, the change in engine technology also entails new requirements for the plastic materials used

Flame Retardancy, Heat and Tracking Resistance of Electric Vehicles

Kunststoffe

Photonik

Optik

Elektronische Bauelemente

Drivers of Electromobility

Electrical architecture in an E-car is significantly more challenging than for conventionally powered vehicles. Particularly for insulation of high-voltage (HV) components, the demands on the materials used are increasing. With specially-tailored materials for electric vehicles, challenges in automotive high-voltage technology can be overcome.

Insulation of high-voltage components in electric vehicles makes high demands on the materials used

Polyamide Specialties for Electromobility

Automotive

Kunststoff

Bauwesen

Baustoffe

High Voltage in Cars

The Chinese automotive manufacturer Geely will in the future use a polyamide 6 (PA6) from Lanxess for front-end (FE) carriers in its vehicles.

The front-end carrier for vehicles by the Chinese manufacturer Geely will be made of a PA6 from Lanxess in the future. © Lanxess

 PA for a Front-End Carrier

Most of the energy in a crash is absorbed by metal parts. A new additional polyamide (PA) crash absorber has for the first time been integrated into the front end of the Mercedes-Benz S-Class. The advantage is that an additional loadpath could be added without significantly increasing the mass of the car.  Close cooperation between the project partners and the use of suitable simulation tools were key to successful realization of this project.

As part of the safety concept in the front end of the latest S-Class, Mercedes-Benz uses a crash absorber made from polyamide.

Crash Absorbers made from PA for the Front End Carrier of the Mercedes-Benz S-Class

Kfz-Sicherheit, passiv

Kfz-Systeme

Kraftfahrzeugtechnik

Accident Protection with Plastics

BASF is expanding its portfolio of flame-retardant engineering plastics for electric vehicles. The new PA66 type Ultramid A3U44G6 DC OR is reinforced with 30 % glass fibers.

The new PA66 type is flame-retardant and meets all the criteria of color stability and heat aging resistance. This enables long-lasting color coding, which is safety-relevant in the sensitive area of high voltages in electric cars.

Farbstoffe

Additive

Flame-Retardant and Color-Stable

DSM sells its Engineering Polymers business to Lanxess and the financial investor Advent. In return, the two companies are setting up a joint venture to which Lanxess is also contributing its PA and PBT business.

Lanxess is outsourcing its engineering plastics business to the joint venture.

Streifinger, Florian

Wirtschaft

Lanxess and Advent to Buy DSM‘s Engineering Plastics Business

Engineering and high-performance plastics as alternatives to metals will be one of the highlights at Lehvoss’s booth.

The smartphone holder consists of recycled PA66 and has been reinforced with 50 % glass fibers.

Focus on Metal Substitutes

At K, Radici will present the Renycle product family. These engineering compounds have a variable proportion of mechanically recycled PA obtained from PIR and PCR.

Reducing weight and ensuring safety are the aims of compounds developed by Radici specifically for electromobility.

Compound

More Comprehensive  Life Cycle Analysis

Flame Retardant Polyamide for Inductive Charging Systems

Electric vehicles can be charged not only at charging stations, but also wirelessly. Here, the energy exchange takes place between an induction coil positioned in the ground and a receiver coil mounted in the e-car.

Electric vehicles can be charged not only at charging stations, but also wirelessly. Here, the energy exchange takes place between an induction coil positioned in the ground and a receiver coil mounted in the e-car.  For the system to function reliably, the coils must be protected from damage. Glass fiber-reinforced and flame-retardant PA66 is particularly suitable for this, as the example of a current wireless charging system shows.

As electric mobility gains in popularity, electric vehicle charging stations are popping up in many places. Electromagnetic induction charging systems for electric cars are a viable alternative to conventional cable systems. Wireless charging systems can help solve the problem of so-called “range anxiety” by allowing vehicles to recharge simply by parking them over charging plates.

In the case of taxis, for instance, the vehicles could be charged while waiting for passengers. In addition, these systems will eventually allow for dynamic wireless charging while driving. This technology is enjoying considerable success, especially in Europe and China. Globally, according to different market research companies an average annual growth rate (CAGR) of more than 30 % for the technology is expected for the next five years.

Wireless charging is based on the principle of electromagnetic induction. When electric current passes through a coil, it creates a magnetic field. This, in turn, generates an electric current in a coil at a certain distance. This way electricity can be transferred from one device to another without physical contact (Fig. 1).

These applications require proximity between the transmitting and receiving devices (a near field). This article refers to a static charging system with the vehicle being charged while standing still in a car park or garage, for example, where the charging system is installed. The transmitter is installed underground and the receiver is located on the underside of the vehicle. For efficient charging, the transmitter and receiver must be aligned. The characteristics relating to the performance and safety of the system are described in detail in the SAE J2954 standard (updated in 2020) and in the GB/T 38775 standard for the Chinese market.

In the design of some components in the emitting and receiving systems, the producer Shanghai Wanji Electronic Technology considered the use of engineering polymers, as they could offer significant advantages compared to metals.

For this application, the most important characteristics that favor the engineering polymer option are:

<ul><li>The ability to produce complex shapes.</li><li>Weight reduction and better “handling” of the components, as in the assembly phase.</li><li> High productivity with lower environmental impact, thanks to less energy expenditure during the processing phase.</li></ul>

To achieve the objectives of rigidity and mechanical resistance, an optimized design was carried out considering the specific characteristics of the chosen material (Fig. 2 shows the buildup of the modules).

The focus was on two components in particular: the covers of the receiving system (transmitter pad) and the receiver pad. As for the transmitter pad, the technical specifications required the passing of severe mechanical tests and the use of materials with good chemical resistance, flame-retardant properties and excellent processability for injection molding with very low warpage.

 The technical specifications in detail are:

<ul><li>Passing a test simulating the passage of a vehicle (tire rolling test).</li><li>Cone drop and ball drop test (IEC61439–5:2014) with a cone weight of 5 kg, a drop height of 0.4 m and an impact energy of 20 J.</li><li>Chemical resistance: testing the effect that accidental contact with organic solvents, such as oils, may have on product performance and material integrity.</li><li>Hydrolysis resistance: in order to prevent accidents related to the installation on the ground, the material should be soaked in water for two days without any problems arising.</li><li>Flame retardancy: UL-94 V0 classification requested for part wall thickness.</li><li>Low coefficient of linear thermal expansion (CLTE).</li><li>Maintaining the integrity of the system’s electro-magnetic signal.</li><li>UV resistance in case of direct light exposure.</li><li>Working temperature: in ordinary conditions, operating temperatures ranging from –40 °C to +55 °C are foreseen. In some cases, for example, in the presence of misalignment during charging, the temperature can rise up to 105 °C. Considering the need for a safety margin, structural analyses were carried out using a temperature of 125 °C.</li></ul>

As regards the receiver pad, some specific requirements were defined:

<ul><li>Impact resistance, in case of accidental contact with objects (typically stones) that may hit the component while driving.</li><li>Expected temperature range between –40 °C and 150 °C.</li><li>Finally, excellent processability and flatness.</li></ul>

Taking into account the required properties listed in the above section, various alternative materials were analyzed, including semi-crystalline polymers and amorphous polymers. The choice fell on semi-crystalline polyamide polymers for several reasons, among which: greater mechanical strength even for long-term properties such as creep, greater fluidity (very important in injection molding given the large size of the objects considered), superior chemical resistance and good UV resistance.

Two PA66 products were successfully tested, one classified UL 94-V0 at 0.8 mm and the other customized to guarantee excellent FR properties (UL 94-V0) at 1.6 mm. Tests are also underway to evaluate PA6-FR, loaded with glass-fiber and free of halogen and red phosphorus, as an additional potential choice for these applications.

The technical data shown in this article refer to the PA66 Radiflam A RV300HF produced and marketed by RadiciGroup High Performance Polymers. It is 30 % glass-fiber filled, flame retardant, classified UL 94-V0 at 0.8 mm. This material, which is already used in various applications in the electrical sector, offers a good compromise among the various technical requirements, including good mechanical properties (Fig. 3, Tables 1–3).

The material is also certified UL-94 V0 at 0.75 mm (Relative Thermal Index, RTI) values: RTI Elec (electrical) 140 °C, RTI Imp (mechanical impact) 115 °C, and RTI Str (mechanical strength) 130 °C). That is why it is even suitable for use in the presence of high temperatures.

Radici also supported Shanghai Wanji Electronic Technology in the component design for the transmitter pad and the receiver pad. For the transmitter pad, given the considerable size of the component, a mold filling analysis was carried out and the injection points were chosen after comparing trials with different configurations. Proper mold filling, compactness and gating lay-out optimization were essential parameters to obtain the expected mechanical characteristics and to minimize part warpage.

Another very important test involved the simulation of the passage of a vehicle over the pad (tire rolling test). Figure 4 shows pad displacement in the y direction after optimization of the part design, injection gating system and molding parameters. As for the pad receiver, a key aspect was the integrity of the component after the impact of a stone weighing 22 g at a speed of 140 km/h. An accurate material characterization, including high speed impact properties, has been provided from Radici in order to perform a reliable simulation.

Components made of Radiflam A RV300HF passed all the required tests and are now mass-produced for this application (Fig. 5).

The construction and design of these components required a detailed multi-functional analysis which was necessary to take into account the multiple, sometimes conflicting, technical specifications. Other decisive aspects in achieving the positive result were the characterization of the material, which involved extensive use of the most sophisticated calculation programs, and the optimization of the geometry already at the virtual model level.

RadiciGroup Performance Plastics  

https://www.radicigroup.com/en

Ausgabenartikel

Wireless charging could increase the range, and therefore the acceptance of electromobility.

Fig. 1. Functional principle of the wireless charging system for electric vehicles: among other things, the system can save scarce space, for example in city centers.

Fig. 2. Components of the transmitting (left) and receiving (right) modules of the inductive charging system: the covers must protect the electronics from damage and have flame-retardant properties.

Fig. 3. Stress-strain diagram of the PA66 Radiflam A RV300HF at different temperatures: the material achieves the necessary values for use in the charging modules.

Fig. 4. Deformation of the charging pad in the y-direction during the traverse test: to achieve  the required performance, the gating system and the injection molding parameters were optimized.

Fig. 5. The transmitter module and receiver module are now in mass production.

Table 1. Mechanical properties of the PA66 Radiflam A RV300HF.

Table 2. Thermal properties of the PA66 Radiflam A RV300HF.

Table 3. Electrical properties of the PA66 Radiflam A RV300HF.

KUint7-22_Radici - Hauptartikel

Erico Spini is global marketing manager at the business unit high performance polymers of the RadiciGroup; <a href="mailto:erico.spini@radicigroup.com">erico.spini@radicigroup.com</a>

David Qi is business development manager for Southeast Asia at the business unit high performance polymers of the RadiciGroup; <a href="mailto:david.qi@radicigroup.com">david.qi@radicigroup.com</a>

Shanghai Wanji Electronic Technology is a global Tier 1 supplier producing products and solutions for the automotive industry. Among them are wireless charging systems for electric vehicles. The company’s inductive charging technology enables electric vehicles to be charged wirelessly.

Read the German version of the article in our magazine Kunststoffe or at <a href="https://www.kunststoffe.de/a/fachartikel/ohne-kabel-dank-passender-compounds-2943162" target="_blank">www.kunststoffe.de</a>