The Enclosure is where our battery pack is contained and is also the most mechanically focused project currently in Battery Box.
Main Tasks for Fall 2023:
Finish Prototyping Board
MountManufacturing Module Mounts
Finalize + Manufacturing Board Mounts
Wire Harnessing
Make Final Product 🥳
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Design Requirements
The design of the enclosure is based on the following requirements:
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Most of the requirements are pretty straight forward, we need cooling because overheating batteries can cause thermal runaway, which is when the batteries enter a sort of amplifying feedback loop where: battery
Battery gets too hot → becomes more resistive because it is too hot → becomes hotter because of increased resistance → gets hotter → becomes more resistive because it is too hot → becomes hotter because of increased resistance → …keeps repeating until it … and this keeps repeating until the battery bursts into flames and our car is gone.
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Figure 2: Thermal Runway of the battery of a car (we DO NOT want this)
We need to consider the ease of removability because we might have to take the box out to make changes to the modules or fix something inside of it. For example, if a single cell in a module becomes non-functional, we have to replace the entire module.
Size and weight are important constraints to consider because we need to make sure our box actually fits into the space that the chassis provides, and it also needs to be as light as we can make it so that the weight of the box doesn’t mess with the center of mass of the car and also because more weight → more energy needed to move the car.
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The full dimension of the box is 693.25 x 400 x 235 (mm). The box itself is made up of fiberglass panels attached to an aluminum frame. On the front and back are going to be two 120mmx120mm 120mm x 120mm Noctua IPPC NF-F12 3000 PWM fans for cooling the modules.
The box sits on four steel flats and is also bolted to two more flats on the front and back to prevents lateral movement.
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The modules will sit as shown in Figure 5, the CAD does not yet show the electrical components like the BMS boards that need to be attached to the modules (BMS in simple terms helps manages all the batteries' performance). The modules shown in Figure 5 below are not the complete versions either, partly because rendering the full modules with every single cell takes a toll on my computer, but the figure below is enough to get the idea across.
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