Last month GM Announced that Heat-Pump technology will be included in all of their current and future electric vehicles based on the Ultium-platform.
The current product line of GM includes the Hummer EV, which is now being delivered, and the Cadillac Lyriq, which will be arriving in the coming years. GM will use the technology to collect low-level waste heat and use it in important ways, allowing their EVs to accelerate faster, charge faster, and go further.
GM’s Heat Pump Technology
An automotive-grade heat pump absorbs and recoups waste heat in the vehicle system. The system in GM EVs uses a compressor and evaporator component system with a specifically designed refrigerant that undergoes a phase change, similar to the systems used by other automakers like Tesla and Toyota.
As a physical process transitions from a gaseous state to a liquid state, it releases energy and vice versa. This will effectively amplify any energy it may scavenge along the way.
A bit tough right? let us dive a little deeper and check out what is a heat pump exactly?
Heat Pumps: What are They?
Heat pumps are designed to reduce the wastage of surplus heat generated by an electric vehicle’s battery and powertrain. They absorb the excess heat created by the electric vehicle’s battery and powertrain, enhancing the vehicle’s efficiency, range, and driving enjoyment.
A heat pump is a device that moves heat around an electric car. Similar techniques are employed in combustion engine automobiles, but we aren’t concerned with them at the moment. Reversible heat pumps can also create heat and then circulate it around an EV as required.
But why do we need to transfer heat? The truth is, we don’t. We could simply cool the batteries and motors by some means (water, air or oil), and then use radiators to return the heat to the atmosphere. But that’s a bit wasteful, and it’s not what electric cars are all about.
One of the most important functions of heat pumps is to transfer heat from heated portions of the automobile that would otherwise be squandered to the passenger compartment. This eliminates the need for the EV’s battery to run a resistive heater to keep passengers warm.
To make it even more simple, imagine that the engine of your ICE car heated up and you have to cool it down anyway so how do you do it? Obviously by circulation water through the engine and how do you cool down the water? By using radiators you send the excess heat to the atmosphere. So the concept of a heat pump is that the heat you want to remove from the engine can be used somewhere the heat is required like heating the car.
This works well when the outside temperature is warmer or sunny…,
What about when it’s below zero degrees?
Reversible heat pumps may also create heat, which can be quite beneficial when the temperature outside the car is below freezing. Electronics, such as batteries, motors, and computer chips, have the disadvantage of performing optimally within a relatively restricted temperature range. As EV drivers in cold climates are well aware, an ice-cold battery is wasteful and can reduce range. Reversible heat pumps can help in this situation.
Reversible heat pumps, as previously stated, may also create heat. They do this by compressing the refrigerant that circulates through the cooling system; refrigerants become heated when compressed. That heat can subsequently be sent throughout the car’s cooling and heating system like the battery.
Warming the battery before heading off on your journey is more effective than waiting for it to warm up naturally. Furthermore, because most EVs can “precondition” before being disconnected from their charger, you may depart with a warm, fully charged battery that will not be affected by the cold.
Now that you have a basic idea about Heat Pumps lets get back to GM
Harnessing for The Best
According to Tim Grewe, GM’s head of electrification, the Ultium platform was designed from the outset to be a modular platform that could accommodate everything from tiny consumer EVs like the Chevy Blazer EV (and Equinox EV) to huge commercial vans. GM believes it can help speed up charging and acceleration and extend range.
According to the company executives, the Ultium platform strategy differs from the thermal system of the existing Bolt EV, since it employs a heat-pump technique to consolidate and simplify the rest of the system.
The heat pump doesn’t add mass even in comparing the larger Ultium models with the Bolt EV confirmed the project manager for the system Lawrence Ziehr. “It’s just a smarter way of connecting the systems.”
Rather than adding more cooling circuits, as was done in the Bolt EV, you can use the drive unit as a cooler for the battery and “not be a slave to the environment of the ambient temperature,” as Grewe put it. The Ultium vehicles have one resistive coolant heater, versus the Bolt EV’s two, and it also eliminates the need for a standalone A/C compressor.
The heat-pump design for GM also helps with preconditioning the battery pack, which involves warming it up before DC fast charging. Battery preconditioning will be available either manually or automatically if a fast-charging destination is chosen in the GM Navigation app or in-vehicle Google Maps.
Surprisingly, to reach peak charge rates sooner warming in general, it does not have to consume all of the battery charges. Grewe highlighted that a large portion of the preconditioning energy in this system originates from drive-unit waste energy.
How Heat Pumps can Save Battery In Winter?
The severe freeze and record-low temperatures this winter highlighted a truth that everyone considering an electric vehicle must accept: cold winter conditions may reduce the effective driving range of certain electric vehicles by 40% or more.
Part of the reason for this is that the resistive heating used in electric automobiles (yep, like the glowing parts in your toaster) consumes a lot of energy. But it’s not only that; the batteries themselves must be warmed to function properly.
Several firms, including the supplier Mahle, are taking a complete look at the cold-weather problem. It launched the Integrated Thermal System a few months back, which the company claims can recoup 20% of the cold-weather loss. This system is one of several developed by vendors around heat-pump technology and other thermal methods to reduce the burden on resistive heating.
Heat pumps improve efficiency by moving heat rather than generating it. In models with heat pumps, a reversible configuration is used to transport thermal energy out of the cabin during hot weather (acting as an air-conditioning compressor) and to bring thermal energy from power components or outdoors into the cabin during cold weather. According to Bosch, a 1 kW heat pump will provide the equivalent of 2 to 3 kW of heat.
Other Models With Heat Pump
The 2013 Nissan Leaf was the world’s first mass-produced vehicle with a heat-pump-based cabin heater, which helped enhance the driving range during the winter months. It is available on all models of the BMW i3 EV, as well as the Jaguar I-Pace and Audi E-Tron. The Toyota Prius Prime and most Volkswagen e-Golf models do as well.
It isn’t available on all-electric vehicles. The Hyundai Kona Electric lacks a heat pump, but the Kia Niro EV has one. Tesla’s climate control system does not include a heat pump, but it does utilise waste heat from the motor and power electronics to warm the battery.
This is the beauty of the EV. They are continuously getting improved, eliminating everything wasteful.
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