In order to accomplish safe cooling on the battery pack, the BMW i3 employs an indirect liquid cooling system, like many electric vehicles. These cooling systems utilize a network of metal pipes to circulate coolant, which dissipates heat away from the battery pack, in a manner reminiscent of internal combustion engine vehicles.
Glycol or polyglycol is the main component of the coolant that flows through the pipes, and when we say “primary” component, we really mean it. One of these two components makes up around 99 percent of the coolant. The final 1% that different coolant manufacturers add to the formula sets them apart.
The final 1% of the vehicle is where the chemicals are added, and this is what actually makes the cooling system sustainable. The mixture is made protective against things like rust and scale from forming in the pipes thanks to these additions.
The i3 must be served by those cooling pipes and that cooling system for the duration of its life. The pipes themselves need to last much longer even though the coolant will be washed away at regular intervals.
The BMW i3 and other electric vehicles employ liquid cooling because it is currently the only workable method for cooling electric vehicle battery packs.
We shall discuss the value of an efficient cooling system in your BMW i3 (or other EV) in the section that follows. The different cooling technologies that have been investigated before deciding that indirect liquid cooling is the best option will next be discussed.
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Is the BMW i3’s easy winter achieved with a smartphone?
Electric vehicles’ range depletes in cold weather, as is well knowledge. The results might be devastating. However, it is not necessary. I’ve been able to avoid the worst of it by paying close attention when I use the BMW.
Have you ever taken your phone out of an inner pocket to see the battery percentage quickly deplete? So it shouldn’t come as a surprise that an electric car’s pack temperature is important.
In general, too much cold causes the internal resistance to increase and cause it to malfunction; nevertheless, this does no harm, and it returns as soon as the temperature rises. On the other hand, overheating the battery can result in long-term damage. The ideal temperature for it is similar to our own: around 20 degrees Celsius.
So, the battery cooling/heating system in autos. Similar to most other devices, the i3 circulates liquid between its cells. The battery is 300 kg or so in weight. Consider the energy required to get it back up to its ideal temperature after an overnight dip in temperature. And when you drive, it draws that energy from within.
I appear to get no better than 2.0m/kWh for the first 20 miles after a cold start through London. Therefore, that excursion consumes 10kWh, or 25% of the total energy. Grrr. However, there is a fix. Look below.
Let’s first examine the other significant energy consumer, cabin heating. The i3’s screen can usefully display how much power and range the “auxiliary consumers” are consuming. Normally, the display is hidden deep within iDrive, but I’ve designed it to appear on shortcut button 7. Starting in a nearly cold cabin and turning up the heat is said to cost at least 15 miles of range, or 10% of the battery’s total energy. Furthermore, this occurs with an i3 equipped with the optional PS530 air-source heat pump, a technology that is more effective than a typical electric resistive configuration.
So I switch to using the seat heaters and turn the heating off or down to just a dribble of air to defog the screen. In contrast, these utilize a very small amount of power.
However, there is an even better response. Preconditioning. I always make sure the car is plugged in till I leave on any day I have a lengthy trip. By configuring it from the car in advance or, much more efficiently, by using the remote phone app, I let it know when I anticipate to leave. Even if the battery is fully charged, it begins to pull current from the socket once more roughly 30 minutes before that time in order to heat the battery and the cabin.
So I get into a warm car and drive off. When preconditioning is used, the same 20 miles that produced 2.0 m/kWh without it produce roughly 4.0 m/kWh. In other words, I’ve saved 5kWh, which translates to a range of almost 20 miles. And as I said, there is even more money to be saved if I utilize the heated seats rather of the heating once we are moving.
Even when the car is not plugged in, you can still warm the interior (but not the battery) using the remote app. It is incredibly wonderful to get into a car that’s already warmed up and desisted if I’m just making short trips and don’t worry about range.
Tearing Down Tesla Segment 4: Tesla Model 3 vs. BMW i3 Battery Cooling System Comparison
Additionally, the Munro engineering team spent some time examining the battery cooling systems for the BMW i3 and Tesla (coolant) (AC fluid). The results are shown here.
Additionally, the Munro engineering team spent some time examining the battery cooling systems for the BMW i3 and Tesla (coolant) (AC fluid).
Background: The cooling system is the main component of the Tesla Model 3 that costs more than the BMW i3 other than the battery pack. The Model 3 needs an additional water pump to drive coolant through the battery cooling circuit, just like other battery packs that use liquid cooling, including the Bolt. The BMW i3, which uses AC fluid, has to move a lot less fluid, therefore the compressor doesn’t need an extra pumping mechanism. However, it could need to be slightly larger than usual to provide for increased demand.
Each battery cell in the pack has full contact along the side of the coolant tube, which is another advantage of the Tesla battery pack cooling system’s operation. This contrasts with the BMW (and the Bolt), which only have contact at the module level with the cooling system (at the bottom of the battery module). As a result, the Model 3’s cells can cool more evenly and pack temperatures can be managed more effectively.
Data show that a 75 kWh battery pack costs roughly $270 for the Tesla cooling system, equating to a cooling cost of $3.60 per kWh, compared to a 22 kWh battery pack costing approximately $84 for the BMW, equivalent to a cooling cost of $3.80 per kWh.
The vehicles’ whole coolant system was disassembled using this methodology. In Design Profit, the installation of the car and the battery pack were recorded to develop assembly costs. The cost of the pieces was then determined by analyzing the manufacture of each item within the cooling racks of each battery pack. In order to more clearly grasp the differences between the vehicles, these expenses are then added together and assessed using Design Profit.
Detailed information on the BMW i3
There is a ton of information regarding the new BMW i3 EV that has been leaked, giving auto experts something to talk about before its official introduction on July 29. The i3 represents a number of firsts: it is the first electric vehicle (EV) to provide a range extender engine as an optional feature; it has a distinctive carbon fiber reinforced plastic body shell; and it has an unheard-of number of connection and autonomy (self-driving) features.
The i3 was created by BMW as an electric vehicle from the bottom up, and the BMW Group also created the lithium-ion battery, power electronics, and motor. The vehicle, which BMW characterizes as “a dynamic and nimble, yet also comfortable luxury car for an urban setting,” was created with complete freedom by the designers. The business claims that the battery pack’s low, central positioning affords the vehicle almost ideal weight distribution and that the electric motor’s close proximity to the driven rear axle gives it unrivaled traction.
The motor, which weighs 110 lbs. and produces 170 horsepower (125 kW) and 184 lb-ft (250 Nm) of maximum torque. A single-speed transmission is used to power the back wheels. Electronic limits set a top speed of 93 mph.
The “single-pedal control idea” is embodied by the regenerative braking technology. The motor shifts from drive to generator mode as soon as the driver lets off the gas, creating a precisely regulated braking action. The i3 produces a powerful braking effect at low speeds and “coasts” with maximum efficiency at high speeds.
The i3’s battery is positioned flat in the Drive module, has eight modules (each with 12 separate cells), and weighs about 450 lbs. It generates 360 volts and about 22 kWh of power. In the event of a problem, individual modules can be changed thanks to its design. A heat exchanger can be used to warm the fluid that serves as the cooling component of an air conditioner. Before a voyage starts, the battery can be preconditioned to its ideal operating temperature of about 70 F. The battery is made to survive the entire lifespan of the car.
BMW claims that the i3 has an all-around range of 80 to 100 miles, which may be enhanced by up to 12 percent in ECO PRO mode and by the same percentage once more in ECO PRO+ mode.
A car was either an electric vehicle (EV) or a plug-in hybrid (PHV), but the i3 will also come with a 650 cc two-cylinder gasoline engine as an option, so it appears we’ll need to create a new category. The range extender, which extends the electric motor’s maximum range to 160–180 miles, is positioned next to it.
Numerous connectivity capabilities are available on the i3, including an inbuilt SIM card that makes it possible to use the ConnectedDrive suite of navigation and energy-saving technologies. Using their smartphone at any time, drivers may communicate with their vehicles using the BMW I Remote app. Driving Assistant Plus, Parking Assistant, a rearview camera, and Speed Limit Info are available driver assistance systems.
Is the battery in the Model 3 liquid cooled?
The largest obstacle to a larger format cell, according to Tesla, was cooling the cell, which their new tabless electrode design solves. Tesla made this statement to us on Battery Day. Due to a cooling issue, Tesla limited the size of the cells in the Model 3 and Model Y to 2170. Tesla is able to switch to this new, much larger cell thanks to the updated tabless design.
A fluid-filled cooling snake that draws heat from the cell’s sidewalls cools the 2170 in Model 3 and Model Y. The pack’s volumetric efficiency is hampered by the cooling snake’s appetite for space.
Tesla Model 3 and Model Y use a cooling snake filled with fluid that is adhered directly to the cell and takes up room in the battery pack. Image courtesy of Tesla
The issue with big diameter cells is that as diameter increases, the cell’s ability to reject heat increases much more quickly than its surface area, making it harder to remove heat from the edges of the cell. Tesla permanently adhered the cooling snake to the side of the 2170 cell to address this issue. At the start of production, Tesla had a steep learning curve and a high rejection rate as he attempted to solve the issues related to bonding the cell to the cooling snake.
Tesla described how this new large-format 4680 cell can cool itself at the Battery Day presentation. The table-style electrode design reduces the cell’s internal resistance.
Tesla has eliminated the modules and is inserting the cells directly into the cast aluminum frame, as was seen during the Battery Day presentation.
Tesla will do away with modules and integrate the cells right into the cast aluminum frame of the vehicle. Image courtesy of Tesla