Enclosure Design Sprint WIP

Sprint Introduction:

Now that we have prototype modules being built and worked on, it’s time for a new challenge of designing the actual enclosure that will hold the battery pack. The challenge of this sprint is to create a REMOVABLE battery box enclosure that is both electrically, chemically, and thermally safe for our driver and battery pack. Design solutions will be discussed throughout the sprint and will be a good way to explore different options and ultimately develop the most safe and effective battery enclosure.

Design Sprint Goals

Obtain experience of bringing a project from idea to completion.
Get accustomed to critiquing each others work
Making self-driven decisions throughout the entire process, starting from basic requirements + constraints, to selecting OTS components/materials
Getting comfortable with holding each other accountable to our own deadlines.
Documenting progress and decisions in a design log

Background

With our current bullet design and chassis, we have the space highlighted in yellow for our enclosure. The dimensions of this space is 568mm x 518mm x 184-384mm (L x W x H). The enclosure needs to fit securely WITHIN the chassis since the enclosure itself isn’t a “structural” component of the car - it’ll be physically protected from most impacts by the chassis. The main focus for the enclosure would be on its electrical, chemical, and thermal properties.

The enclosure also needs to be able to fit 9 battery modules connected in series as well as the battery protection circuits, main fuses, fans, and the supplementary batteries. Our prototype module designs are in GrabCAD (let @Owen Li or @Eric Zhao for access), so you can use them as a rough estimate for the size of the pack. I made some rough measurements here https://docs.google.com/spreadsheets/d/1COhGy7h4_lRnH3cEM6AoeaJnYIRIbwWA2hEuo6A-T7M/edit?usp=sharing but the designs will probably change and be updated throughout the design sprint.

The specific dimensions of the enclosure are very likely to change as the car is developed. The main goal in this design sprint is to explore different ideas such as enclosure type, enclosure material and manufacturing process, mounting methods (module to enclosure, enclosure to chassis), and thermal regulation (cooling system).

I put all the relevant regulations onto this task on Trello (sorry they’re screenshots lol):

As we go through each phase of the design sprint, I’ll highlight relevant regulations that apply.

Timeline & Deliverables:

Read this before starting for a good introduction to battery module design:

Previous car’s enclosure design logs: Battery Enclosure MSXIV

NOTE - The previous care was a Multi-Occupant Vehicle design, and their enclosure was secured between the passenger seats and did not need to be removed from the chassis overnight. We don’t have passengers in our car, and we have way less batteries so our enclosure may look very different.

Here is Micah’s PDF library, lots of useful materials for more in depth reading: Relevant Research

ASC 2024 Regulations: ASC2024-Regs

Sample Design Logs:

https://docs.google.com/presentation/d/10ylmWYR_Er4OoCQ5UJIiymEIGTLgjv72pMDDRAr9HMI/edit?usp=sharing

Kevin Bui FYDP FDR - Password is “midsun”

Charge Port Mount Design Log

https://drive.google.com/drive/folders/1fCtR9BuxDQ6isJEk4DCbPftVV9Hr1BZh?usp=sharing

Phase 1 [DATES HERE; ~1 week] - Review with [Ourselves?]:

The goal for this phase is to get as many ideas and concepts as possible for enclosures that we can explore throughout the rest of the design sprint.

There’s a pretty large variety of enclosure types that different teams have used in the past. For example, below are two different designs:

Battery box secured to the hood of the car (lifted to the right in the picture)

Come up with (at least) 2 different ideas for enclosure types
- How will it fit into the chassis and connect to the electrical and ventilation systems?
- How will we remove it for impounding?
Create sketches and/or basic CAD models for each enclosure
List out pros and cons for each idea

Relevant Regulations

Enclosure must be designed so they can be removed from the vehicle and placed in impound.
The battery enclosure must be secured to the solar car chassis so as to prevent them or the modules within from coming loose in the event of an accident or rollover
Battery enclosures can have a forced ventilation system that must pull exhaust to the exterior of the car
- The exhaust must be connected directly to the exterior of the vehicle and away from any airstream that may reach the driver

Phase 2 [DATES HERE; ~? week] - Review with [?]:

Choose one idea to further develop
Create full cad within chassis assembly
Basic manufacturing process (like high level steps)
Material selection? (99% chance fiberglass tho lol)

Mechanical