By Dr Khasha Ghaffarzadeh, Research Director, IDTechEx

The automotive industry is fast becoming a significant market opportunity for suppliers of conductive pastes and similar materials, soon to rival photovoltaics (PVs). Almost every major paste supplier with a global profile is re-organising its product portfolio to capture this rising trend.

Multiple significant trends are re-shaping the automotive industry in an unprecedented way. Vehicles are becoming increasingly electrified, which will affect the powertrain and battery charge. In particular, this trend will increase the number and capability level of power electronic devices such as inverters, DC-DC converters, on-board charges and others inside vehicles.

In parallel, cars are also becoming more autonomous and safer. Many higher-level automated driver assistance systems (ADAS) will be implemented on the road to the long-term goal of full autonomy. This trend inevitably translates into higher electronic content per vehicle, both in terms of sensors and processors, a trend that will be further accelerated by increased vehicle connectivity.

Comfort and aesthetics are also improving, including as seamlessly-integrated human-machine interfaces (HMIs), in-seat heating, efficient de-foggers, multiple-functionality lighting, and more.

Electrification
IDTechEx Research forecasts that on-road electric cars will reach approximately 40m units by 2029, with different degrees of electrification, from 48V mild hybrid to plug-in hybrid, full hybrid and fully electric. These vehicles will require power-conditioning units (power electronics) to charge batteries, convert high-voltage outputs to low-voltage inputs for auxiliary electronics, and to drive electric motors and capture energy from them.

Each power-conditioning unit fulfils a different set of requirements, which means different power levels, operating temperatures and thermal shocks. These conditions dictate many technology choices including the semiconductor (Si vs SiC vs GaN), device architecture (MOSFET vs IGBT) and power module/packaging materials.

The link to conductive pastes comes in the packaging materials – more specifically, the die attach and even the substrate attach. The primary technology choice today is the SAC solder, a tried and tested, lead-free, cheap technology that comes in different formats. In general, the performance trend is toward high operating temperatures and increased cycle life. The higher temperature tolerance translates into reduced die number/area and shrunk module and package size.

High safety and autonomy

Pastes are already used in simple safety functions including occupancy sensors, de-misters, etc. Occupancy sensors are a highly successful screen-printed product that measure the presence and weight of occupants to properly control the response of the airbag deployment system. Conductive pastes are also used in LTCC-based electronic boards used in the automotive industry for safety or monitoring functions. These ceramic boards are selected for high reliability, tolerance of heat, moisture and vibration.

This trend is likely to accelerate. The number of electronic boards will increase. Today, there are many individual self-contained electronic systems; in the future, there may be a centralised architecture to handle and process all the data.

Improved comfort, design, aesthetics and energy-saving

Conductive pastes are already part of the ongoing trend to improve comfort, design and aesthetics in vehicles. In one example, pastes are used in seat heaters, with the entire large-area heater being printed. The conductive paste might also be used as a die attach for high-power LEDs, used for energy saving and aesthetically differentiated lighting.

One interesting trend is that pastes could also be used in novel human-machine interfaces (HMIs). Here, special conductive pastes will enable In-Mold Electronics (IME), a process that replaces mechanical switches with structurally integrated electronics. This will give rise to elegant HMIs that will save space and weight. This technology is not straightforward to implement and has suffered from long learning and development times. But, after several false starts of the past, it is now commercially available, and readily found as an embedded heater (de-fosters) on the curved plastic cover of LED lamps. There are many more close-to-market prototypes targeting the vehicle interior in the pipeline too.