Category Archives: Manufacturing

Electric Car Batteries Are Topic of Presentation by ATS CEO Dr. Kaveh Azar

Electric Car Batteries

ATS CEO Dr. Kaveh Azar will deliver a presentation on the thermal management of electric vehicle batteries on Thursday, Sept. 22. (Photo courtesy of Wikimedia Commons)

On Thursday, Sept. 22, Advanced Thermal Solutions, Inc. (ATS), a leading-edge engineering and manufacturing company focused on the thermal management of electronics, will host the New England Section of Society of Automotive Engineers International (SAE NE) for a tour of its Norwood campus and a presentation by ATS founder, President, and CEO Dr. Kaveh Azar.

Dr. Azar’s discussion is entitled, “Battery Thermal Management – The Gateway to the Successful Operation of Electric Vehicles.” He will review the role of temperature in the longevity and performance of nickel metal hydride (NiMH) and lithium-ion electric vehicle batteries; drawing analogies between battery temperature and the junction temperature of modern electronics. As Dr. Azar notes, “Both play an identical role in successful operation of their respective systems.”

There will be a discussion of the analytical methods and design criterion for predicting battery temperature and establishing safe temperature limits. Dr. Azar will present high-level possibilities for thermal management in the electric vehicle sphere as well as cooling options that are deployed for battery thermal management. Current cooling designs can be active or passive. There are forced air, liquid cooling, natural convection and conduction systems used by manufacturers.

Several thermal solutions that engineers have incorporated include increasing the thermal density of the battery, using phase-change material to store transient heat loads and graphite-impregnated paraffin waxes as gap fillers. It is also important for the designs to control temperature distribution across the battery to avoid degradation of cells.

Thermal management is crucial in the design of electric vehicle batteries because temperature has a direct correlation on battery life and performance. It will affect the battery’s ability to store and deliver a charge, weaken polymer- or fiber-based cell dividers, and could potentially lead to thermal runaway.

“The engineers who will design the next hybrid vehicle battery packs will need to be cognizant of the growing need for thermal management,” read a recent article on coolingZONE. “The increased need for thermal protection, due to safety considerations; the reduced thermal capacity, due to lesser mass; and the reduced workable volume are among the challenges to be faced. The hybrid vehicle we may soon drive must have reliable and intelligent cooling systems to cool down their high-density battery packs.”

Why is this topic of particular relevance now?

Electric vehicle sales worldwide have jumped 57 percent from 2015 to 2016, according to data reported by Bloomberg New Energy Finance. The article referenced a Bloomberg report stating that electric vehicle sales could be as much as 47 percent of the automotive market by 2040 (dependent on factors such as oil prices). In the U.S., manufacturers have been urged by President Barack Obama’s EV Everywhere challenge to make electric cars as affordable and convenient as gas-powered vehicles by 2022.

Like cell phone technology in the past two decades, electric vehicles have the potential for widespread usage and to wide-ranging effects inside and outside of the automotive industry. The “digitization of the transport system” will effect, among others, oil companies, car dealerships, maintenance services, and utility suppliers.

“If it is hard to predict when phase change in complex systems begins, it is even harder to predict where it ends,” said Michael Leibreich and Angus McCrone, the authors of the Bloomberg article. “No list of potential impacts of the ‘Transformation of Transportation’ can be complete. However, one thing is for sure: if our predictions for the uptake of electric vehicles are anything like correct, there is no part of the global economy which will not, in some way, be affected.”

Currently, electric vehicles cost an average of $30,000 and travel 100 miles or less on a single charge. Tesla (Model 3) and Chevrolet (Bolt EV) have both promised electric vehicles that will travel 200 miles on a charge within the year. Other car makers, such as Volkswagen and BMW, have announced plans to turn a large portion of their production to electric vehicles in the next few years as well.

While the changes in infrastructure and the length of time that most car owners keep a vehicle (11 years on average) have limited electric vehicle sales to this point, according to Christopher Mims of the Wall Street Journal, the next vehicle that most consumers purchase is likely to be electric.

Mims explained, “It is the nature of disruptive technological shifts that it seems like nothing is changing—until it seems as if everything is changing at once. Electric vehicles have been a long time coming, but they now represent such a clear and present threat to the gasoline engine that Mr. Fox, of the service-station association, now recommends that members signing long-term contracts for fuel include an option to renegotiate if more than 10 percent of a state’s fleet goes electric.”

Electric vehicles offer a smooth drive with better acceleration, less moving parts requiring less maintenance, better air quality, and a better platform for autonomous driving, said Bloomberg. Electric vehicles are the future and that means designing better, longer-lasting, higher-performing batteries will be the future as well.

Cooling those batteries will be critical. As Dr. Azar will explain, without proper thermal management the electric vehicle battery will be inefficient and unable to provide the performance that consumers demand.

The Sept. 22 event is free for SAE NE members and $5 for non-members. It runs from 6-9:15 p.m. with tours of the ATS campus from 7-8:00 p.m. and Dr. Azar’s presentation at 8:00. Register online at http://www.sae.org/servlets/sectionEvent?PAGE=getSectionEvents&OBJECT_TYPE=SectionEventAdmin&HEIR_CODE=MS045#249128&saetkn=w1aFMMls8Y or contact SAE member Jeff Mobed at jeffrey.mobed@gmail.com or 508-367-6565.

ATS’ Standard Board Level Heat Sinks for PCB

We’ve just released our new line of standard board level heat sinks. These stamped heat sinks are ideal for PCB application, especially where TO-220 packages are used. Available now through Digi-Key Electronics​ or at this link from ATS http://www.qats.com/eShop.aspx?produc…

 

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ATS maxiGRIP and superGRIP Heat Sink Attachments

Advanced Thermal Solutions John O’Day and Len Alter showcase the patented heat sink attachments maxiGRIP and superGRIP. With its patented and discrete design, these heat sink attachments are well worth it for being your only choice for a cost-effective, high performing thermal solution.

Casting a Light on LED Cooling with Die Cast Heat Sinks

Advanced Thermal Solutions work in casting aluminum heat sinks allows us create large, rugged, and reliable heat sinks and enclosures in a single piece.  Such work carries a number of advantages including enclosures and heat sink in a single unit, reduced part count, reduced final manufacturing complexity.  ATS’s John O’Day sat down with ATS engineers Joe Gaylord and Anatoly Pikovsky regarding our engineering in cast heat sink design to discuss two specific customers projects, both in LED Lighting.   The first company is a  company focusing on LED stadium lighting and the other specializes in LED industrial lighting.

John: What kind of value add did ATS add to the stadium lighting company for their cast stadium heat sink?

Anatoly: Well, this company tried to make the casting for their Stadium LED light for almost a year. They went to many different vendors and nobody could actually build what was needed. They started to cast the first prototypes but they developed cracks. ATS was brought in to see if we could solve the technical and manufacturing problem. Our involvement made it possible for them to ship their stadium lighting on time to be installed in the University of Phoenix Stadium.

Ephesus Stadium Light

Joe: One thing we did was to change the fins a little bit to improve heat transfer and manufacturability, changed how the actual casting tool was made.

Anatoly: We also created a version of the heat sink from sheet metal as a backup, in case the casting failed.

Joe: We did CFD modeling to determine fin efficiency too. In the current design fin efficiency is very good but we thought we could improve it further, so we found that a much shorter fin version would perform just as well but this stadium LED lighting company was already down the design cycle and needed to get this product out the door. We also did work developing a version with heat pipes too, to give the customer multiple data points on what was possible.

John: So we created multiple options for the customer as backup so they could make this shipment for University of Phoenix Stadium on time. It sounds like we take partnering with our customer’s very seriously.

University of Phoenix Stadium

Joe: That’s true we do take partnering seriously and in this case there was a great deal of investment on ATS’s part.

John: So we’ve done casting for another important lighting customer too haven’t we?

Joe: That’s right, an LED company that makes several types of LED lights, some for food chillers like you might see in department stores and they also make canopy lights for gas stations. The canopy lighting LED’s were what we worked on.

Anatoly: If you ever look up while pumping gas you’ll likely see their LED lights in the overhangs above the gasoline pumps.

Joe: So the model they had previously was a molded plastic shroud with a PCB board, LED array, and extruded heat sink on the inside of the shroud of the cooling device. Essentially a big extruded aluminum heat sink, all bolted together (credit senior). Their goal was to increase the number of LED’s, power and lumens in these lights. Thermally, their target originally was 100 Watts, then it climbed to 150 Watts, then it came down to about 120 Watts.

John: So what did we do to make their design better and casting better?

Joe: Our goal was to get rid of the plastic shroud and the extruded aluminum and replace those with a cast piece. We suggested casting for this design since it would create a shroud that allowed for heat transfer. It eliminated a two piece design of heat sink with shroud allowing this LED customer to simplify manufacturing while meeting their thermal performance requirements.

John: Was it easy to come up with this design or did it take several iterations to get to the final design?

Joe: Well, as you know, ATS has a 3-Core Design Process where we do a quick analytical model of the design, move to computational modeling using Flotherm or CFdesign, and finish with an empirical model for physical testing in our thermal characterization lab. This process helps us to reduce the actual time it takes to do a proper heat transfer solution design. For this work we did a lot of thermal modeling with CFdesign.

Heat Sink Design Engineering Process, ATS

Anatoly: There were some key challenges in this design: First it required natural convection cooling. Second, we had to design to cool 120 Watts. Third, the outside ambient temperature can be up to 40 degrees C when a gas station is in the desert.

Joe: For natural convection cooling you need some headroom for the air to convect. We had designed this thermal management solution for a minimum headroom of 1-inch from the heat sink to the canopy over a gasoline pump. Allowing air to come into the heat sink and circulate out was a major challenge requiring excellent fin efficiency, a consideration for spreading resistance, and the mechanical packaging over the LED array. The weight of this casting had to be taken into account too since it would be outside in a canopy over gas pumps with people standing under it. Finally, the industrial design was an important aspect as well since it was outside and had to look attractive. We took time to carefully sculpt the heat sink fins in the final design to account for both aesthetics and thermal performance. Our final design was a machined, open enclosure with fins on all four sides, so that air flow can come up and through from all sides.

International Lighting Canopy Light

John: When we completed testing in our thermal lab with the model we had machined, did we move to casting then?

Joe: Yes we did. Our design was set to cast in two pieces so that the cost to manufacture was within the LED customer’s requirements. The end result was a powder coated single unit, with the electronics box built into the cast, that fit both the PCB and LED. All that was needed as a cover. It simplified the manufacturing process, reduced the manufacturing cost and met their requirements for overall price and thermal performance.

To learn more about ATS’s die cast heat sinks and design services, please email us ats-hq@qats.com or call us at 781-769-2800.

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High Fin Density Heat Sink Manufacturing, Is Zipper Fin Best?

High fin density heat sinks can be fabricated via skiving, bonded fin, folded fin and zipper fin technologies. This video talks about the different types and about how Zipper Fin is a cost effective choice at high volume.  The video interview is followed by a transcript of the interview.

**Hey Joe how’s it going? **

Great John, how are you?

**Good, thanks for stopping by marketing. **

Always a pleasure for engineering and marketing to come together.

**It really is and we love being in marketing because you can see some of the new products that are happening along with some of the new technology ATS is bringing forth and the way that we are dealing with our customers. I see you brought by some new technology here for us? **

Yes, new but not so new. Zipper fins is what we have here and we’ve been doing this for some time. They’ve been popular for years and years. They find a specific place in the market depending on their need and we have deployed them with great success.

**So, what exactly is a zipper fin? Can you explain the manufacturing process, the special technology or? **

Zipper fin is a multi-step assembly process, the zipper itself being made out of a sheet metal that is formed into a specific shape. That material is usually aluminum or copper and it has certain features on the fin itself (credit shakita). When placed together each fin is interlocking to its neighbor. When it’s all assembled it’s soldered to the base of the heat sink it’s a rigid body. It’s very reliable as far as fin density, shape, and its size.

**Now, why would a customer want us to build a zipper fin system? Is it cost or manufacturing quality or better heat transfer? **

Zipper fins compared to other designs that you have heard of called bonded fin. It’s similar to what we have but the tooling is a lot higher. One of the benefits with a zipper fin is you can actually manufacture a very high aspect ratio fin profile without high tooling cost. So, if you want really tall fins, really thin fins, and really tightly packed fins zipper fin may be the solution.

**That’s for more surface area right? **

Surface area exactly and also this type of zipper fin creates a duct. So when the zipper is covering the entire fin field, it creates a duct in the airflow which is much better for thermal performance.

**These are hollow in here and the reason for that is because its duct airflow, so it actually creates both a heat sinks and a duct in one piece. **

We use a lot this as well for active heat sinks with air movers, fans, or blowers. This heat sink here is in a system but its duct flow a zipper pack and also some customers even put an interface material on top of a zipper pack like this and conduct heat to the lid of a chassis.

**Do customers find it useful using this kind of device instead of other types of heat sinks in specific areas like military, or for example appliances? And is it really cost or volume driven? **

It’s mainly volume driven. Here at ATS we have a lot of zipper fins tooled up and ready to deploy on a heat sink base. So depending on the complexity on the base itself and the need for the surface area, and fin density based on the airflow these things have to align to be able to utilize a zipper fin. There are some things we cannot do via extruding, or skiving, or forging that we can do with a zipper fin.

For instance, either with copper or aluminum we can have a zipper fin that’s 0.2 millimeters thick. We cannot do that with a skiving process or an extruding process.

**You mentioned skiving, now would a customer choose this over skiving or would they make a decision based on premise not because they like one or the other? **

It really depends on what they need of the solution itself. Low volume skiving is comparable to zipper fin profile and most customers choose to skive first , but in high volume there is a breaking point where it makes sense to go to a zipper fin. With skiving we can skive aluminum and copper. A copper heat sink skived is very heavy, one of the benefits of zipper fin heat sink is we can have a have a copper base that gives us that heat spreading we can add an aluminum fin profile which reduces the weight significantly.

**There are other technologies that people use with thermal management such as ATS’s patented maxiGrip and superGRIP technologies that allow a perfect connection with the chip and allow the use of face changed material. Could those also be applied to a zipper fin? **

Yes, so as you see on the zipper fin heat sinks the fin neighbors each other all the way through. We can easily have maxiGrip or a superGRIP over the middle portion. We don’t always have to have the fin field throughout the entire width of the heat sink. We can split the fin back up if we need to allow specific features on the heat sink or clip on methods such as maxiGRIP, superGRIP, or z-clips. Push pins works as well, this is hard mounted onto the board. This heat sink is cooling about 12 total components on the bottom of this heat sink, this one utilizes the cooper for spreading and again it’s that weight factor we want to reduce so we use aluminum fins to which need to be nickel-plated when you solder.

**Now how about these two, I know these are from different applications than this one but they seem to all use zipper fin? **

The good thing about a zipper as well is if you were to stamp a fin for the zipper you can also during that stamping process allow for holes in the fins to allow crescent heat pipes. So here we have one tool for the fin itself to allow for the heat pipes and you can see this is the base of the heat sink that touches the component which is the evaporator section and the condenser section is actually the zippers away from the component then mounted to the board. But again, the zipper fin profile allows us to reduce weight significantly especially with the heat pipe application and it is one time tooling low cost production.

**What about this particular one? **

This is an all copper solution which is a stamped base, flat basic material, and a standard zipper fin copper profile that’s soldered on. So again it’s a multi-step process where you make a long zipper to break it off to your specific width, place it on the heat sink and wave solder. So again, when performance is critical these are performing some of the best numbers for heat sinks for that given envelope. Again, we can significantly increase the aspect ratio, reduce the fin thickness, and also fin density.

**And we’ve done a lot of these so it’s really a part of our design services and the we really help our customers get to the exact solution they need and not just some off the shelf solution but we give them the best cost and the best effective heat transfer.**

Exactly. We have many extrusion profiles in stock we also have many zipper fins in stock as well that we can pick and choose from depending on length, height, and orientation on a base to utilize for a solution. They need not all be square, we have some unique fins that are tooled up and we can also use the zipper fin to allow for a fin profile to be a circular (360 degrees) and we use that with a lot of active heat sinks and fans. So an axial type of zipper fins.

As you mentioned some of the industries; LEDs, embedded, military, and telecom and data-com.

**Consumer and appliances I would imagine maybe concerning the volume and the price? **

Exactly, once you do tool up if it’s something new then production will be a very low cost solution.

**If people want to know more about zipper fins they can contact us at www.qats.com.**

Absolutely! We’re here designing a lot of these and others if these are the right solution, we have the options.

To learn more, email us at ats-hq@qats.com.