High Performance EVs need Dependable Thermal Management

PEEM (Power Electronics and Electrical Machine) technology is essential with electric-drive vehicles. PEEM technology comprises three main elements: power electronics (e.g., boost converters and inverters); electric motors; and thermal control and system integration.

Thermal control is a critical element to enable power density, cost, and reliability of the other components. It also is an important component of battery modules. “The plug-in hybrid Chevy Volt, due out in November 2010, will carry 16 kilowatt-hours and go up to 40 miles on a full charge,” reports Matthew Wald for the New York Times. “The battery pack alone would run from $9,600 to $16,000. And that does not count related parts like the system that maintains the temperature of the cells within an acceptable range and manages the charging and discharging.”

So, if companies are to mass produce and warranty electric drive passenger vehicles, they want them to have dependable thermal management. Unfortunately, the ICE (Internal Combustion Engine) paradigm still prevails in design of thermal management systems. Mitch Olszewsk of ORNL (Oak Ridge National Laboratory) warns that OEMs have in their mind that they would like to integrate the “power electronics cooling with the combustion engine cooling system. They’re going off on a pathway of high temperature systems, rather than looking at low temperature systems.”

“ORNL developed a cylindrical design for its inverter, and used a cylindrical capacitor. The power electronics cards (IGBTs and diodes) are mounted inside the center of the cylindrical capacitor, and this whole zone (slightly above the top of the capacitor) is submerged in liquid R134a refrigerant.” For comparison, the ORNL image on the left also shows a 1000 µF capacitor from a baseline Semikron inverter (top), and the SBE 500 µF for the ORNL inverter (bottom).

As reported by Green Car Congress, ORNL researchers have “developed an innovative two-phase “floating loop” cooling system for direct-contact cooling of power electronics and motors.” Even better, their design exceeds “DOE FreedomCAR 2020 targets for power density (13.4 kW/L).”

In a separate post Green Car Congress also reported on development at PNNL (US Department of Energy’s Pacific Northwest National Laboratory) of MOHCs (Metal Organic Heat Carriers). As GCC commentator clett keeps saying, “this is the century of the Organic Rankine Cycle!”

Nanostructured metal-organic heat carriers, or MOHCs, can help to improve thermodynamic efficiency of a heat recovery process.

While Oak Ridge researchers envision the benefits to geothermal power production of the rapid expansion and contraction capabilities of MOHCs in a new biphasic fluid, GCC commentators were quick to pick up on other possible applications, e.g., GCC commentator takchess suggests that Raser Technology might be doing similar things.. Raser Technology has expanded into geothermal power as an another application for its advanced power electronics and electrical machines. This blog envisions that MOHCs could be useful not only to PEEM thermal management and even to the range extender in passenger electric vehicles.

GCC Recommended Resources

Curt W. Ayers, James C. Conklin, John S. Hsu, Kirk T. Lowe (2007) A Unique Approach to Power Electronics and Motor Cooling in a Hybrid Electric Vehicle Environment. (IEEE Vehicle Power and Propulsion Conference, 2007)
C.W. Ayers, J.S. Hsu, K.T. Lowe (2006) Fundamentals of a Floating Loop Concept Based on R134a Refrigerant Cooling of High Heat Flux Electronics. (22nd IEEE SEMI-THERM Symposium)
DOE Vehicle Technologies Program Power Electronics and Electric Machines FY 2007 Progress Report

New geothermal heat extraction process to deliver clean power generation (scienceblog.com)

(PEEM)

4 Comments

jcwinnie

Posted 2009-8-1 at 9:24 am | Permalink

Green Car Congress relays word of a change in leadership at Raser.

Jim Spellman has assumed the leadership of Raser Technologies’ Plug-in Hybrid team as of today. Patrick J. Schwartz stepped down as President of Raser Technologies at the end of July 2009 to pursue other opportunities.

Schwartz joined Raser in 2006 and, while leading Raser’s Transportation and Industrial business segment, was instrumental in helping to drive the successful completion of the extended range electric vehicle (EREV) project unveiled this year at the SAE Congress in Detroit, MI..

Spellman was the Vice President of the Transportation and Industrial segment, and also joined Raser in 2006. He has more than 20 years of engineering experience with motors in the automotive industry. Spellman came to Raser after working for Delco Remy, a former division of General Motors, for more than 27 years. Among his many responsibilities at Delco, Mr. Spellman was the director of hybrid technology.

Given those credentials, I doubt whether the new boss will shy too much from the dominant ICE paradigm. Have to wait and see.
jcwinnie

Posted 2009-8-2 at 6:15 am | Permalink

Speaking of high-performance electric vehicles, Ghosn is making good on his promise to deliver.

Nissan wants to sell the electric car batteries not included. The battery pack then is leased.

While pricing is yet to be announced, Nissan CEO Carlos Ghosn told the crowd that the car without its battery will be “very competitive” with comparable internal combustion models. The monthly cost to lease the battery and fill it with electrons, he added, will be less than an average month of fill-ups at the gas station.

More at Autoblog Green.
jcwinnie

Posted 2009-8-4 at 8:37 am | Permalink

Via Autoblog Green, we learn that Behr “has considerable experience in three different technical solutions for battery cooling: cooled air; refrigerant, and secondary loop solutions.” The company’s U.S. branch is now establishing an engineering group just to focus on battery thermal management.

From the Behr America press release:

In support of the company’s accelerated development activities within the fast-growing hybrid and electric vehicle market, Behr America has formed a Battery Cooling Group at its headquarters in Troy to meet the increasing demand for thermal-management technology.

The new group, managed by Fred Pumper, manager, Thermal Solutions and Validation Test, Behr America, will focus on growing the company’s battery cooling activities as well as support Behr’s Group in Stuttgart, Germany.
jcwinnie

Posted 2009-8-6 at 8:56 am | Permalink

Autoblog Green reporter Sebastian Blanco cautions e-car aficionados that the Mini-E has more than its share of problems.

We’ve heard the stories about the charging problems with BMW’s MINI E lease program and understand that paying $850 a month for one of these electric cars doesn’t appeal to everyone. Still, the issues that some early adopters are dealing with with these EVs are pretty dramatic: the car going into neutral when you step on the accelerator is a big one, as is paying an extra $1,500 for a home wiring upgrade. Also, the MINI E sends out a warning that the batteries are too hot when the ambient temperature is high. BMW recommends that, when this happens, drivers take a break, maybe smell the roses or something like that. More standard ailments – like brakes that need repair – are also present in the MINI E fleet.

After Gutenberg