Modules 10/11 Practice

Question 1

List and describe the primary steps in manufacturing an EV, as divided by typical factory layout.

Answer 1

Drivetrain Production
- motor and drive electronics parts created, then go to assembly
- both go to powertrain assembly
- Powertrain, Exhaust, brake , Steering/suspension and battery all go for assembly onto chassis
- then sent for final assembly w/ body

In Parallel, there is body/electrical production:
- body is being formed in the press shop, the body shop (w/ sub assembly parts), then is painted and sent for final assembly

Question 2

What are the primary reasons why EVs cannot be produced with a greater degree of parallelism in the manufacturing line?

Answer 2

• complexity of battery integration
• precision in high voltage systems
• quality and safety testing
• Supply Chain and Part dependencies

These factors create dependencies and a need for sequential processes that limit the extent to which EV manufacturing lines can operate in parallel.

Question 3

What parts of EV production require the most human-operated assembly steps and why? What impact does this have?

Answer 3

• Wiring Harness
• substantial manual labour involved, highest QC activity on the line, high cost of failure
• strong motivation to simplify wiring harness (every wire saved is a substantial benefit)
• protocol changes ( LIN vs CAN vs wireless)
• Topological Changes: less modular design, less distributed design?
• Power delivery, energy harvesting?

Question 4

List and describe two high-volume QC processes used on EV assembly lines. Why might these be
used and where?

Answer 4

• Vision Based QC
  automated vision-enabled systems are preferred for quality control, especially for load/unload steps

Automated Detection
- 2D feature detection and registration
- Colour/QR/marker detection
- Line/bead detection

These methods are preferred bc they are:
- turn key solutions
- well understood, rule based vision methods
- do not require extensive upfront training costs

May be used during the following processes:
- Component verification
- Visual inspection
- Wiring Harness checks
- Surface defect detection
- Registration and alignment

Question 5

List and describe two low-volume QC processes used on EV assembly lines. Why might these be used and where?

Answer 5

Testing Battery terminal connections for milli-ohm or micro-ohm resistance range
- slow cycle time, possibly manual operation (post-install) - apply to minimal connector positions

Time Domain Reflectometry (TDR)
- testing for detection of open connectors/conductor faults
- used during wire harness assembly

Question 6

What is flexible manufacturing and how might it be applied to EV production?

Answer 6

• reducing reconfiguration costs, increasing parallel operability, multiplexing and interleaving of production.

for EV production:
- make work cells larger equipped with a wider variety of more general tools
- increase step count per work cell
- allow rerouting of production that is not strictly linear.

Question 7

List and describe four emerging technologies that are or will become part of the typical EV production process in the near future.

Answer 7

Powdered Metallurgy
- a manufacturing process that produces precision and highly accurate parts by pressing powdered metals and alloys into a rigid die under extreme pressure.

Carbon Fiber
- traditionally hard to work with in volume, but are now becoming commercially viable

Smart Materials
- shape-metal alloys (wire changes shape when heated)

Additive Manufacturing
- mix of FDM and SLS technologies may be used in future EV Production (printing parts )
- mostly limited to prototyping stages
-strength and materials selection/properties already viable/better in some cases.

Question 8

During DFM, what type of changes to a design are most impactful? What is the trade-off for
this?

Answer 8

• structural and architectural changes are most impactful of positive metrics (ex: cost)
  ex: reducing number of components/ BOM count

Question 9

List and describe five examples of electrical architecture-level DFM changes/checks/modifications
one might make to a design.

Answer 9

• reducing connector positions by moving to a shared supply low-side/high-side driver
• consolidating off board connections to one connector per functional group
• move board-to-boar communications to a node based communication protocol to reduce PCB count
• trim feature set
• focus of ASICs at the top level to reduce complexity.

Question 10

List and describe five examples of PCB-level DFM changes/checks/modifications one might make to a design.

Answer 10

• component consolidation (consolidate passives into single families when possible, shrink BOM count)
• Component Sizing (stick to larger sizing when possible)
• copper allocation adjustments (move high current traces to top or bottom layer, allow higher rise over ambient, use solder fill and heavy copper weight)
• EMI/EMC Considerations
• Prototype Feature Removal (remove vestigial features)

Question 11

List and describe five examples of component-level DFM changes/checks/modifications one might
make to a design.

Answer 11

• remove vestigial features
• consolidate connectors
• use production variants
• supply chain verification (ensure components are in stock)