Evaluation Engineering - 28

THERMAL MANAGEMENT

temperatures of 100°C. Careful consideration of board layout, heat spreaders
and other methods can ensure that these
surfaces meet industry requirements.
It is important to note that any and
all changes to even a single component
within a vehicle can result in intended
or unintended system-level changes.
Making a change to the PCB layout can
cause a change to the overall system.

A unique vantage point

Figure 3: Lab vs. in-situ monitoring and performance.

Simulation and validation tools
Simulation and validation of thermal design models are crucial steps in producing
an accurate and credible design, and assist with anticipating and solving problems in the overall automotive design.
Accuracy is absolutely critical when
designing a board and, with the advancements in technology, design requirements
are becoming tighter and more stringent
than ever. Detailed test and simulations
are performed iteratively until simulation results correlate with empirical
data. Modeling provides both security
and peace of mind that the design is going
to function properly before ever making
it to the manufacturing floor. Steps that
should be considered include:
1. Modeling
* Capturing the physics accurately
* Power levels
* Component placement
* PCB layout (copper layout)
2. Temperature plotting
3. Transient simulations, testing, and validation of thermal
margins vs. data sheet ratings
In addition to accurate modeling of the
solution, consideration must be given as
to where and how it is packaged within
the vehicle, as that can also have significant impact on the effectiveness and
overall cost of the design. Additional considerations include:
Module heat locations and internal
heat spreading: Both how and where

EVALUATION ENGINEERING OCTOBER 2019

Molex

modules are packaged can have both
advantages and disadvantages. Modules
generate heat, so design measures are
needed to mitigate the impact. Solutions
that feature embedded modules, whereby
the module interface is embedded in the
dashboard of the vehicle and the actual
module is located elsewhere so heat can
be more easily vented or dissipated, are
ideal in this situation.
Inlet and laminar airflow and temperature: The ambient temperature is
usually read without any airflow so, as
a result, testing is performed in an enclosed environment, representing the
actual condition of the vehicle and generating more accurate results. Within the
vehicle, these types of components are
typically packaged in areas with ducts
or harnesses or other types of packing
constraints.
Placement of components: The
placement of various components can
affect thermal design performance and
consideration must be given to design decisions such as assembly direction, flow
characteristics, resistance and coolant
effects-to name a few.
Enclosure thermal management:
Outside faceplates must have a lower
temperature, as that's where users interact with the module so it must not be too
hot to the touch. This surface will act as
a heat sink and steps must be taken to
isolate this portion of the modules. If not
done properly, these surfaces can reach

Today, data integrity and processing
power are essential to support the development of intelligent and autonomous
vehicles. Improper thermal management
can lead to poor performance, reliability
issues, shortened product life and safety
concerns. Innovative solutions meet the
challenges of thermal management in the
connected vehicle of the future.
REFERENCES

1. ITSdigest, "470 Million Connected Vehicles On
the Road by 2025." February 2018.

Gary Manchester is director
of new product and technology development in Molex's
Connected Mobility Solutions
business unit. With 30+ years
experience at Molex, he currently leads the
company's work in autonomous vehicle
networks and user interface products and
technology.
Don Mueller is manager of
mechanical product development in Molex's Connected
Mobility Solutions business
unit. He has 25 years of mechanical product development experience, and
has led Molex' mechanical product development team during the last 4 years.
Kiran Vanumati is CAE Engineer in Molex's Connected
Mobility Solutions Business
Unit. He has over 14 years of
experience in electronics thermal management across various industries. He
is currently involved in developing thermally
sound automotive infotainment and networking
modules using simulation and testing.

Evaluation Engineering

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