Maxitherm Has New Advanced Heating System For Electric Cars

NOV 13 2018 BY MARK KANE 45

Maxitherm to reduce energy consumption of heating by 30%?

Before electric cars, efficient heating never bothered car manufacturers as the waste heat of the internal combustion engine provides plenty of heat that can be used during the winter to warm up the cabin.

In the case of EVs, heating requires the vehicle to consume additional energy the from traction battery, which in turn decreases range significantly – as the battery capacity is usually not that high and heating takes a lot of energy (up to several kW). One hour of heating can reduce the state of charge by several kWh on top of what the car needs for driving.

Because of that, heated seats, steering wheel and heat pumps, as well as preheating before driving, become favorable options.

But that does not exhaust all possibilities. Under the European Union-funded Maxitherm project in Germany, an alternative heating system is under development.

The idea is to place additional electric heating elements under a vehicle’s roof and carpets, into the seats and seat backs and along the door panels. In effect, 30% less energy could be consumed to maintain passenger comfort. Who knows, maybe it will be good enough to skip the heat pump altogether.

Rafik Maxi, the project’s technical manager explains:

“The MAXITHERM heating system integrates a technical fabric comprised of both electrically conductive and non-electrically conductive fibres directly into the vehicle’s structure. The system provides direct and fast heat to passengers and is more cost-efficient than any solution available on the market today.”

Here is more on the project:

MAXITHERM heating mats utilise MaxiTex, a patented heating system owned by one of the project’s partners. MaxiTex consists of a special control system and a textile capable of dissipating heat homogeneously over an entire surface. The MAXITHERM mats are placed under a vehicle’s roof and carpets, into the seats and seat backs and along the door panels.

“With this system, it is possible to control the heating intensity and the maximum temperature independently,” says Rafik. “The temperature threshold can be set up for each area of the vehicle separately, providing you with maximum flexibility in terms of setting temperature preferences for each occupant.”

An attractive solution

Ute notes that the prototype vehicle has proved successful, offering high-efficiency and low energy consumption. “We are now monitoring its behaviour under real driving conditions, and this autumn and winter we will be able to measure real values in Germany’s harsh weather conditions,” she says.

The project is currently working with a number of automotive manufacturers who are interested in installing the system (or parts of it) into their vehicles. The team is also seeking additional funding to support further upscaling and marketing of the MAXITHERM system.

“To a critical extent, we successfully developed a system that could serve as a solution for driving electric cars – or any other means of electric transportation – in cold weather without losing range,” concludes Rafik. “As our solution helps EVs overcome the issue of limited range, MAXITHERM is attracting the attention of some global players in the automotive industry.”

Source: MAXITHERM — Result In Brief

Categories: General


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45 Comments on "Maxitherm Has New Advanced Heating System For Electric Cars"

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Part of the difficulty (at least up here in Canada) isn’t so much the low cabin temperature, it’s the fog that builds up in the interior glass. At least from what I’ve seen, in order to get rid of that, you need moving warm air.

Or the low-mostture air that an A/C produces.

Proper cars normally create a layer of dry AC air over the windshield. The moisture from your breath should never reach the glass.

Joel..fog on the interior glass is exactly the problem I am having with my Ioniq PHEV. I have ordered a 12 volt heater to see if that would extend my electric only season. I am surprised I am going to this trouble but I really get a kick out of the e-drive.

This will be great until the next company decides to run tubing under door panels, carpets and roof, all using heated glycol from the car’s motor and inverter. In extreme cases they could hook a heat pump up to warm the water a bit.

But – in general – resistance heat and batteries don’t mix well. Unless you mean gold wires in the windshield (to minimize defrosting heat), and run the driver’s electric gloves, heated underwear, and electric socks off the 12 volt accessory jack/cigarette lighter.

The motor and inverter don’t generate enough heat to raise the temperature of that much glycol.

How much heat – exactly – do they make?

Tesla Model 3 has done away with simple resistance heaters in favor of using the motor/inverter to generate heat while propelling the car by deliberately dialing down the efficiency and scavenging the generated heat into the glycol loop that heats both cabin and battery. Fewer things to fail, at least…

“Deliberately dialing down the efficiency” to intentionally generate waste heat?

No. Just no. Tesla does absolutely everything it can to maximize the efficiency of energy drawn from the main battery pack.

You don’t understand. They decrease efficiency on demand only when heating is required. I.e. when the resistance heater would be used otherwise and would consume exactly the same amount of excess energy.

I don’t recommend heated underwear (not sure if such thing is made). But heated vest works great even for cars, probably better than heated seats (SparkEV has heated seats as standard equipment). Heated gloves and chaps are musts for motorcycling in winter.

Each heated garment (gloves, chaps) take over 5A of current while accessory plug typically has 10A fuse. That means one may not be able to run more than one heated garment at a time.

Both of the heated seats together in my Large Car Kia Amante only drew 3 1/2 amperes each. GM accessory outlets provide 16 amperes continuously. That is 764 British Thermal Units/ Hour. A sedentary adult produces 300 btu/hour, or 400 if extra cold. Tripling the heat a person is exposed to (1 part his own and 2 parts by heaters) is sure to be enough for most drivers under most circumstances (like anything above -40 degrees). Yes there is heated long underwear:

A 12 volt system version would draw around 1/2 ampere. Assuming even 4 adults that will not cause any energy shortage, nor would affect mileage significantly as warming the entire car does now.

Aren’t there winter jackets on the market with micro element threads that run off a small rechargeable lithium battery? I know I saw one in a Popular Mechanics a few years back. Not a concept, but a consumer product.The pack is held in place by Velcro and also can charge your phone and/or devices.

The micro/nano heating element threads were developed for the military during winter patrols in freezing Afghanistan.

I’ll have to research. They are slightly spendy, but in an effort to maximize range in an EV during vwinter…Hey, all ideas accepted!

Yes, DeWalt and Milwaukee both sell heated hoodies and heated jackets. Milwaukee sells a 12v adapter cable to power the jacket/hoodie from a 12v “cigarette lighter” plug. I think their intended market is forklift/skid-loader drivers, but it should work very well for an EV driver.

“I don’t recommend heated underwear (not sure if such thing is made).”

Lots of hunters swear by battery-powered heated socks, altho I don’t know what brands are best.

I think I saw something like this in the clothing industry a few years back. Better to heat the parts of the car that absorb the initial heat than heating air.

If you want to save your precious kWh then wear a 12V heated motorcycle vest and gloves 😀

The lithium battery powered micro heating element winter jacket would be even more efficient.

Heatpumps move heat to where it is needed. Heatpumps are 3X more efficient than resistance heat like Maxitherm. If a car has AC, it can be setup to have a Heatpump by adding a reversing valve. Resistance heat is still required for the coldest days so it is understandable the heatpumps are a niche product.

The heatpumps used in cars are efficient, but they suffer as the temperatures fall. I know people keep using examples of home heatpumps that are huge to show the benefit of modern heatpumps, but they will not fit under the hood of an EV. There’s a reason companies like Tesla and GM doesn’t use heatpumps. It adds cost because you still need a resistance heater along with the heatpump. For EV’s with smaller batteries it might make sense to use a heatpump, but as the battery capacity grows the % drain of the resistance header has less effect on EV range.

Dated comment: Japanese heat-pump technology is as close to fantastic as anything can be lately.

That said, there are much more important considerations here than just adding a reversing valve – but it basically is oil miscibility, and refrigerant flow rates since the temperatures are vastly colder during the dead of winter than in the hot California Sun. That’s all I’ll say since the last time I got detailed a commenter complained I was getting too technical.

Why are you trying to compare a cars heat pump requirements to a home heat pump. A household heat pump has to heat 50x the volume of a vehicle cabin. So logically a vehicle one can be much smaller.

Not necessarily. Car air conditioners these days are around 2 tons, and the old Cadillac Boats used to brag they had 5 ton air conditioners, or enough for a 3500 square foot house.

LEAF does the heat pump reversing switch. I can’t imagine why Tesla has not. As you point out, every car with AC has a heat pump that could be used in all but the coldest weather.

Radiant heating should work in a car. Objects are heated not air. It is certainly less cumbersome than heating seats and steering wheels.

We still need to defrost the glass and deal with condensation from human breath and wet clothes.

With autopilot we can get rid of the humans, then we don’t need to heat!

With autopilot you may need to heat all of the cameras and sensors.

Heat pumps are a variation of an air conditioning system. Most modern units are up to four times more efficient than resistance heating as long as the outdoor temperature is 40 degrees F. or higher. Around 30 F. it becomes as efficient as resistant heaters. A really advanced concept would be to cool the motor windings. The colder the windings the more efficient the motor becomes. Supercooled motors are less than one-fourth the size of a regular motor.

Again, the times they are a changin’. Expect higher performance heat pumps as time goes on.

To show you how DATED your comment is – some heat pumps have a COP of 2 (1/2 the electric usage) at 5 deg F. At 30 degrees F, far from breaking even – they are well under 1/3 rd the electric usage.

Heat pumps with this capability are larger. They will not fit under a hood. Show me one that is small enough to fit under a hood.

Sadly, for the folks living in the frigid northern climates that need the range for commuting, I believe the best option is the diesel heaters that have been used in big trucks for decades. I know it burns diesel with greenhouse emissions, but the fuel consumption is very, very low an you would only use it in the winter on days when you really need the range.

For those that aren’t familiar, these heaters are a small stand alone burner that is tapped into the vehicle’s liquid coolant loop and heats the coolant, allowing you to use the OEM heater without running the engine. In the case of the BEV, you can heat the cabin without taxing the battery. It’s not a difficult modification either. I’m surprised there aren’t more people with BEVs using them. Like I said, the technology is decades old, well proven, safe and the kit can be had for about $800-$1000.

It comes as standard in a few EVs in Norway.

In my passenger van, I have 2 extra diesel heaters. One hydronic, that heats the water (The same the engine heats up), and one diesel heater that only heats the cabin air.
They supply the equivalent of 15 000 Watt, so there is almost no limit on how warm I can get the cabin.
Normally, they only run for 5 minutes, and it is more then warm enough. Still feels as a safe option, when I’m crossing remote mountain passes in the winter.

In Sweden, the electric buses use “biogas” as a fuel to heat them in arctic cold weather. It’s believed to be carbon neutral when burned.

Maybe when the WATER COOLED ICE is invented we’ll have something called PHEV’s invented (Future I3s, VOLTS, Priui, Clarities, etc), that will oxidize hydrocarbons, producing exothermic reactions that will not only push the car – but will efficiently heat the cabin at no marginal fuel usage.

Oh, wait…

I was intrigued until I read “… in cold weather without losing range”: that’s marketing BS. Whether that system is better than existing ones remains to be proven. They are fishing for investments.
However the discussions here about heat-pumps is much more interesting than the story above!

The answer is energy retaining molecule.
Energy can come from sun or car plugged in at home.

That’s a very interesting article. But my understanding of what it is saying is that the liquid is photo-switched. It changes states from light (photons). I don’t think it would be efficient to use artificial lighting to energize this fluid. You could just as well use any liquid fuel for the application we are discussing here.

Interesting approach. Passive house researchers showed quite a few years ago that one of the main effects on winter time comfort in a home is wall temperature. Given two houses, both with inside air temperature of x degree, the one with warmer walls due to greater insulation will feel much more comfortable, so it makes sense to insulate and warm the roof and doors in a car.

I’m not cold in my cars, I just need the fricken windows defrosted (and fast). That means blasting hot air at the windshield and getting the resistive heater in the rear window going first thing. Why my Tesla Model 3 does not do this when I tell it to pre-heat the car, I do not know. For those talking about the efficiency of heat pumps at 40+ degrees, many people I know are still wearing shorts when it’s 40 degrees. I certainly am not concerned about being cold at those temps, just need the visibility. I hate scraping ice on the outside of my windows, and it really sucks when you have to scrape on the inside.

Has anyone heard of a coat?

When riding a snowmobile for fun, we used to wear ski suits and goggles to keep warm, or at least to keep from freezing.

But in an enclosed car, I expect the air to be warmed. If a BEV can’t do that properly, that’s not a case of drivers being wusses; that’s a case of the BEV not being fully competitive with a gasmobile.

The need for heating in very cold conditions is yet another reason why BEVs need large battery packs, and not the small “right-sized” ones which some of the more idealistic (and less practical) EV advocates assert auto makers should be using.

Heat the car, electricity, and not “without losing range”? Where is the juice coming from?

A better HVAC box would do wonders. Use AC compressor to dehudify RECIRCULATED WARM CABIN AIR. add fresh air through face vents at low rate. Clean windows. Fresh air. Heat scavenging at exhaust vents in the trunk. Very little energy wasted. EV manufacturers hardly do engineering :@

As some posts recommend using heated motorcycle clothing in EV’s to save the battery for the traction motors, another way to keep warm would be to install bicycle-type pedals driving a generator, this way the batteries are being charged while the driver is exercising which also causes an increase in body temps– hey, practical solution here, don’t knock it unless you have a better idea to keep warm in cold winter climates.