Tag Archives: Energy/Renewables

Cosmic Ray Failures of Power Semiconductor Devices

Post Syndicated from ABB Semiconductor original https://spectrum.ieee.org/energy/renewables/cosmic-ray-failures-of-power-semiconductor-devices

Cosmic ray failures are sudden events caused by cosmic particles in devices subjected to a high electric field strength

Introduction
The increased failure rate of traction propulsion converters in the early 1990s, lead to the recognition of cosmic ray failure mode for power devices. The famous experiment, whereby the failure rate of devices in a blocking condition in a laboratory were compared to the blocking failure rates in a salt-mine, was undertaken by Siemens engineers. The absence of failure in the salt mine supported the hypotheses of cosmic ray particles as the root cause of the failures [1]. Further tests executed by ABB on the Jungfraujoch at 3580 m above sea level (a.s.l), confirmed this hypothesis. Additional tests with proton beams made it reproducible in the laboratory. This leads to improved design and statement in regard to ruggedness of power semiconductor devices.

Cosmic particles
Primary cosmic particles (typically protons) are generated in remote areas of the universe e.g. in the supernovae. The particle energy can be extremely high; several orders of magnitude higher than artificially accelerated particles in the most powerful accelerators such as the one in the CERN research centre. But these are not the particles that directly cause device failure on the earth. During their travel towards the earth, many particles are deflected by the sun and earth’s magnetic field. This is why the cosmic particles detected on earth vary with the 11 years activity cycle of the sun. Those particles that are approaching the earth interact with the atmosphere. In this interaction, a shower of new, secondary, tertiary, … particles (protons, neutrons, electrons, …) are generated. Up to an altitude of 10,000 – 15,000 m the generation of particles is dominant, whereas nearer earth altitudes, absorption of particles dominates. At the surface, the x’th generation of the initial primary cosmic can be detected (terrestrial cosmic). A typical flux is 20 neutrons per cm2 per hour (sea level New York), see Figure 1.From this description, one can conclude that the flux of terrestrial cosmic particles is dependent on altitude. Dependencies on the latitude, due to the influence of the earth’s magnetic field, and the actual sun activity, can be neglected for a first order estimation.

As the atmosphere is absorbing cosmic particles, other materials could be used as a shield. For example, a 45 cm layer of concrete reduces the intensity of cosmic neutron particles by half [3]. But as for a significant shielding effect, heavy shielding would be necessary which is not an option for many applications.

Failure mode

Most cosmic particles pass the semiconductor devices without any interaction. With a certain probability the cosmic particles interact with the nucleus of a silicon atom in the device. Then the energy of the particle displaces the hit atom and may generate new particle species. Although a microscopic defect in the silicon crystal is generated, the concentration of the generated defects, even during the lifetime, would not lead to a measurable degradation for typical irradiation conditions, for a non-operating device. The situation might be different for operated semiconductor devices. Logic devices, or memories, store their information, typically, through a small charged capacitor. Here the deposited energy of a cosmic particle may lead to a bit flip and therefore to a loss of information. In devices that support an electric field, the deposited energy of a cosmic particle may lead to a local charge cloud that is amplified through the electric field. A short current pulse may be detected at the biased device. This effect is used for particle detectors for physical experiments to identify and count high energetic particles. In devices that support a high electric field, like power semiconductor devices, the deposited energy may lead to formation of a streamer, a conducting pipe in the blocking semiconductor device see Figure 2. In such a case the device may be destroyed as shown in Figure 3.

The failure of devices due to cosmic rays are sudden events, without any precursor. Therefore, they are often called ‘Single Event Burnout’ (SEB). The probability of a device failure depends on the intensity of the cosmic irradiation (therefore on the altitude and shielding as previously explained), and strongly on the electric field strength and distribution in the power semiconductor device (therefore on the applied blocking voltage and device design). Other influencing parameters are device temperature and beam direction.

Testing

For testing of semiconductor devices for cosmic ray ruggedness, data needs to be acquired in a reasonable testing time. This can be reached by:

  • Testing many devices in parallel to get a higher probability of failure events during the test time.

  • Increasing the sensitivity of the tested devices, by operating them during the test at higher blocking voltages than in typical applications. The failure rate for a typical application then needs to be extrapolated. This method was used in the beginning of the cosmic ray ruggedness investigation .

  • Another way to accelerate testing is to increase the cosmic ray flux. As seen before, the intensity of cosmic particles increases to an altitude of 10,000 – 15,000 m a.s.l. In the beginning of cosmic ray ruggedness investigation of power semiconductor devices, this effect was used to reduce test time. ABB operated a test lab at the High Altitude Research Station, Jungfraujoch in the Swiss Alps at 3580 m, see Figure 4. At this altitude the intensity of cosmic particles is approximately a factor of 10 higher that at sea level.

But even with acceleration, testing times are still in the order of several months to years. This is too long, especially for verification testing during the development phase of semiconductors with several learning cycles.

A much faster way to get the relevant data is to use artificial particle beams, like neutron or proton beams. Studies showed, that the failure rates generated by natural cosmic particles very well correspond to data generated in artificial particle beams, see Figure 5. The test time for such a setup reduces to minutes.

Specification of devices ruggedness

Some power semiconductor suppliers specify the cosmic ray ruggedness of their devices either in the data sheet or in an application note e.g. [5]. The parameters for the failure probability, such as applied bias, junction temperature or altitude, are given for an unshielded device. This helps to estimate the failure rate of the power semiconductor under the individual application conditions and to choose the right device.

References

[1]

H. Kabza, H.-J. Schulze, Y. Gerstenmaier, P. Voss, J. Wilhelmi, W. Schmid, F. Pfirsch und K. Platzöder, „Cosmic Radiation as a Cause for Power Device Failure and Possible Countermeasures,“ in Proc. of the 6th Internat. Symposium on Power Semiconductor Devices & IC’s, Davos. Switzerland, 1994.

[2]

O. C. Allkhofer und P. K. F. Grieder, ,,Cosmic Rays on earth,“ Physics Data , Bd. 25, Nr. 1, 1984.

[3]

F. J. Ziegler, „Terrestrial cosmic rays,“ IBM J. Res. Develop., Bd. 40, Nr. 1, pp. 19-39, 1996.

[4]

C. Findeisen, E. Herr, M. Schenkel, R. Schlegel und H. Zeller, „Extrapolation of cosmic ray induced failures from test to field conditions for IGBT modules,“ Microelectronics Reliability, Bd. 38, pp. 1335 – 1339, 1998.

[5]

H. Zeller, „Cosmic ray induced breakdown in high voltage semicoductor devices, microscopic model and phenolenological lifetime prediction,“ in 6th International Symposium on Power Devices & IC’s , Davos, Switzerland, 1994.

[6]

5SYA 2046-03, „Failure rates of IGCTs due to comsic rays,“ ABB Application Note, 2014.

Infographic cosmic rays influence on semiconductors

Failure rates of fast recovery diodes due to cosmic rays

Failure rates of IGBT modules due to cosmic rays

Failure rates of IGCTs due to cosmic rays

3D-Printed Semiconductor Cube Could Convert Waste Heat to Electricity

Post Syndicated from Tracy Staedter original https://spectrum.ieee.org/energywise/energy/renewables/3dprinted-semiconductor-efficiently-converts-heat-to-electricity

Here’s how these cubeoids could harness waste heat from steel plants

From his office at Swansea University in the United Kingdom, associate professor Matthew Carnie has a good view of Tata Steel’s furnace stacks. To some, those chimneys rising over Port Talbot are unsightly. To Carnie, they’re an opportunity. They emit a good portion of the plant’s waste heat, which overall has the same power output as some nuclear plants, says Carnie—around 1,300 megawatts, according to his calculations.

With that much potential power waiting to be captured, Carnie and his research team have developed a hybrid, 3D-printed semiconductor material that converts waste heat into electricity. It’s 50 percent more efficient than another inexpensive semiconductor material, lead telluride, that’s screen-printed, and the new material could be assembled cheaply into a device that converts up to 10 percent of heat wherever it’s applied.

“Ideally, they could be deployed in areas where there is high-grade waste heat and be used to generate power to help with energy efficiency,” says Carnie. With one-sixth of all energy used by industry in the United Kingdom pouring into the atmosphere as waste heat, the possibilities are big, he says.

Ionic Materials Explores Plastic Electrolyte for Lithium-Ion Batteries

Post Syndicated from Mark Anderson original https://spectrum.ieee.org/energywise/energy/renewables/nextgen-battery-tech-iteration-rather-than-disruption

Replacing a liquid electrolyte with a plastic one could lead to lithium-ion batteries that are safer and more energy dense

Better batteries for electric cars and grid energy storage may be just one revolution away—whether in fuel cells or flow batteries or supercapacitors. But there’s a company in Massachusetts that’s betting the evolution of existing technologyrather than a revolution—will determine how we power future EVs and store renewable energy. 

“Lithium ion has this massive scale,” says Erik Terjesen, senior director of licensing and strategy for Ionic Materials, based in the city of Woburn. “The people who build lithium-ion factories—the LGs, the CATLs of the world—are building massive capacity for lithium-ion.” These billions of dollars already invested, Terjesen says, represent inertia that will resist revolutionary new battery technologies—especially if lithium technology can offer more energy storage, safer products, lower prices, and be made in existing factories.

As IEEE Spectrum profiled in 2018, Ionic Materials is developing a plastic, solid-state electrolyte to sit between a rechargeable battery’s anode and cathode. The electrolyte acts as the conduction medium through which lithium ions flow from anode to cathode and back again—providing the basis for many charge-discharge cycles in the battery’s lifetime.

The most effective and resilient electrolytes in lithium-ion batteries to date have been liquids, which conduct ions well but do nothing to keep the cathode and anode from ever touching. This has been the job of a thin plastic membrane with tiny micron-sized holes in it called the separator, which allows lithium ions to pass through.

The problems come when there are manufacturing defects, tears in the separator, a puncture in the battery, or a growth of stalactite-like “dendrites” bridging cathode and anode through the separators. In all those cases, a short circuit could result. That is where the other downside of the liquid electrolyte comes in: It’s highly flammable. Which is why there have been reports of the (rare) exploding laptop, smartphone, and EV.

Ionic Materials’ solid-state electrolyte is, of course, its own separator. And it’s non-flammable.

“From the dialogues we’re having with electric vehicle OEMs, it’s exciting for them to have an inherently safe battery in their cars that works in the same way,” Terjesen says. “We’re not talking about a new design. We’re not talking about a new cell format. It fits into their world today.”

Since 2018, Terjesen says, the company has been establishing partnerships and announcing investors, including the French oil and gas company Total, A123 Systems, Dyson, Samsung, Renault-Nissan-Mitsubishi, and Volta Energy Technologies.

“We are aware of the fact that there is obviously a lot of hype that comes with the battery industry in general,” Terjesen says. “So our CEO Mike Zimmerman says you really need to prove what you’re saying, rather than just making claims.”

The areas the company is now most carefully investigating around their polymer electrolyte, he says, are safety, energy density, and cost.

The first two, he says, go hand in hand. The greater a battery’s energy density, the more the electrolyte’s safety matters. “We think our polymer can work with more energy dense anode and cathode combinations,” he says. “As people try to squeeze all the energy they can out of these cells, by default, the cell will become more volatile. We think the safety question will only continue to increase as you look at these higher-energy chemistries.”

The question of price, Terjesen says, is also important. In 2010, the industry produced batteries costing some US $1,200 per kilowatt-hour. By 2014, that price had fallen to $600/kWh. As of last year, it was south of $200/kWh. And now, Terjesen says, many industry players are trying to get below $100/kWh. (Ionic Materials does not release data on its cost or ability to enable battery companies to drive their unit cost down.)

“Getting below ($100/kWh) will be challenging, because the fundamental materials themselves are commodities. And the raw materials themselves have a certain price,” he says.

For instance, cobalt is both expensive and controversial, with much of its global reserves found in the Democratic Republic of the Congo—where corruption and disputed labor practices have led Elon Musk to swear off the mineral in Tesla’s future-generation cars.

“We’ve learned that cobalt is often used in these cells as a stabilizing agent,” Terjesen says. “So if we can create greater safety with our material, it opens the door for the potential to reduce or eliminate the cobalt.”

However, Terjesen says Ionic Materials is ultimately chemistry-agnostic. They do not even build batteries. The company only provides the solid-state electrolyte for battery-makers to develop whatever next-generation solid-state batteries the market will bear.

“There isn’t a single chemistry that we’re betting on,” he says. “We’re not going to the market and saying—you have to do this chemistry or that chemistry. We have multiple chemistries that we’re working on with multiple partners with our polymer.”

In other words, Ionic Materials is trying not to disrupt an industry accustomed to disruption.

“Most people who look at solid-state [batteries] think, it’s not a disruptor of lithium ions,” Terjesen says. “It’s the next phase of lithium ions.”