NREL Power Electronics Thermal Management and Packaging Reliability (Text Version)

This is the text version of the NREL Power Electronics Thermal Management and Packaging Reliability video.

Image of circuit board.

Onscreen text: NREL power electronics thermal management and packaging reliability

Video of car driving in town.

More and more electric cars are hitting the road, translating into greater energy efficiency and cleaner air.

Video of person paying with a credit card at a fuel pump and inserting nozzle into side of car.

While the typical American spends more than $1,400 each year on gas to get from Point A to Point B, most electric car owners only pay about $540 per year to charge up.

Video of in-vehicle screen displaying data about energy use and driving range.

But electric car sticker prices can still be high, and performance doesn’t always match that of conventional gas-powered vehicles.

Video of car driving in the country and then in a town, with vehicle labeled as 100% electric.

Improving the performance of power electronic components will be critical if electric cars are to claim the 50% market share experts predict.

Video of charging nozzle inserted into side of car.

Arial video of sign with National Renewable Energy Laboratory, U.S. Department of Energy printed on it in the forefront, with modern-looking buildings in the background. 

Onscreen text: NREL R&D is boosting power electronics performance, while driving down size, weight, and cost.

Research at the National Renewable Energy Laboratory, or NREL, is helping boost the performance of these power electronics while driving down size, weight, and cost.

Outline of sedan with interconnected components, including a battery charger, high voltage battery, bidirectional converter, inverter, and electric motor with connection to the wheel; the high voltage battery also connects to a DC-DC converter and ancillary loads.

Electric vehicles rely heavily on power electronics, including inverters, converters, and chargers to control the flow of electricity between the battery, the motor, and other powertrain components.

Image showing inner workings of an all-electric vehicle with an electric traction motor, power electronics controller, DC-DC converter, thermal system, battery (auxiliary), onboard motor, transmission, charge port, and traction battery pack.

In electric vehicles, these components need to operate at higher temperatures, voltages, switching frequencies, and power conversion efficiencies.

Onscreen text: NREL’s thermal management research is delivering smaller, more affordable, and energy-efficient devices.

That's where NREL's thermal management and reliability research comes in.

Two images of exposed vehicle bases with wheels (no cabins), one of which is an old-style car base with a large engine on it while the other is a sleek, modern-looking car base.

Image of scientific equipment on large, metallic, rectangular base followed by an image of a person in a laboratory setting putting objects into an equipment box that includes a circuit board.

NREL's thermal management strategies make it possible to develop smaller, higher-performance, and more energy-efficient power electronic components, like the wide bandgap technology that is a strong interest for integration into future electric vehicles.

Animation showing the joining of the individual layers of previously described components.

Video of computer monitor showing the previously described small rectangular component with three parallel pieces of attached metal, along with text including CREE, HT3201-R, High Performance Half-Bridge Power Module.

NREL's wide bandgap thermal management strategies led to the world's first commercial high-temperature, high-power-density, automotive traction drive inverter, an innovation recognized with an R&D 100 Award.

Video of same small rectangular component with three parallel pieces of attached metal and a small rectangular circuit board, both of which include the CREE label.

Thermal research at the package level focuses on dye and substrate integrated cooling strategies and heat transfer enhancement technologies.

Video of fluid boiling followed by several images of black-and-white rectangular shapes in boiling fluid.

System-level thermal research and analysis supports the development of thermal management strategies for the entire power electronics system with packaging solutions that increase power density and reduce cost.

Video of person in laboratory making adjustments via a computer touch screen and lifting a plastic cover above a circuit board.

NREL's research on the reliability of new electronics packaging results in longer-lasting components that operate more efficiently and dependably under higher temperatures.

Onscreen text: Pinpointing causes and areas of failure increases component lifespan and reliability.

Video showing several processes: cracking, delamination, and breaking.

By pinpointing causes and locations of failure such as separation, delamination, and cracking, researchers can help industry partners design more reliable components.

Onscreen text: NREL researchers examine how materials and designs respond to a variety of conditions.

Materials and designs are put through their paces as researchers age power electronics under accelerated thermal and humidity conditions.

One body of work quantifies the aging of large area bonded interface materials that adhere the insulating substrate within a power module to its base plate.

Video of person in laboratory setting putting small strip of material between two metal components.

NREL researchers focus on improving the bond strength and lifetime of these interface materials.

Video of person pressing a button on a remote-control device while the small strip of material brakes into two pieces. A computer screen shows this activity via a black-and-white image.

And recently, sintered silver, a potentially more reliable and environmentally friendly alternative to traditional high-temperature soldering, is given much attention.

Using a variety of non-destructive techniques, such as acoustic microscopy, allows researchers to observe the development of voids, cracks, or delamination within sample layers.

Video of scientific equipment containing moving water with a cylindrical metal device moving across a small square shape.

Video showing close-up view of computer monitor with dynamic graph.

Transducers generate ultrasound with a frequency customized to each sample material, making it possible to image an internal layer with maximum resolution.

Video of a series of black-and-white circular images showing progressive changes.

Periodic scans of the sample expose changes over time, revealing areas for attention.

Onscreen text: Mechanical evaluation determines viability of alternative materials and designs.

Mechanical evaluation of sintered silver is an important step in exploring the viability of this high-temperature alternative to traditional solders.

Video of person placing the device below some frame-like equipment that includes an area with holes at its center that fits above the small device.

Video of person putting small piece of material into a segmented holder.

Video of person pressing on the top of a piece of equipment that contains a small box between two metal cylinders. As the person presses on the top cylinder, the space between the cylinder and the small box gets smaller.

Video of vice equipment within large metal frame. Two cylindrical shapes move toward each other, reducing the space between them. INSTRON is printed on the equipment. 

After a stencil printing process is used to produce samples with consistent bond line thickness, researchers heat them up to 250˚C to trigger the sintering process and synthesize a double lap sample configuration with two interfaces of sintered silver for mechanical testing and measurement of changes and strain.

Results are incorporated into constitutive models for use in finite element numerical modeling.

Video of vehicle frames moving along a manufacturing assembly line with mechanical arms extending to work on the frames and sparks flying in the background.

Onscreen text: Ultimately NREL’s early-stage research helps put more electric cars on the road.

After NREL completes this early-stage research, industry figures out how to incorporate the new technology into cars coming off the assembly line.

Video of closer view of mechanical arm working on a car frame.

Video of components under a car hood. While two of the larger components have a box-like outer shells, other components appear more traditional looking.

Video of a person driving a small car to a charging dispenser below a photovoltaic panel and then inserting a charging nozzle into the side of vehicle.

All of this power electronics research and development is conducted with the goal of reducing component size and cost or improving performance and reliability, which will make electric cars more affordable and appealing to even more drivers.

Learn more about NREL's power electronics research and partnership opportunities on our website.

Onscreen text: Learn more at