Automotive Engineering - December 2022 - BET11

2.3 lower than for pure water, all other
parameters being equal.
As the operating pressure of the coolant
in the cooling circuit increases, the
amount of liquid leakage increases linearly.
Temperature influences leakage
rate because the viscosity of the coolant
decreases with increasing temperature.
For example, the leakage rate for glycol
as a coolant increases by a factor of five
when the operating temperature rises
from 20 °C to 80 °C. This is true over long
periods of time. In terms of longer periods
of time, even a few drops of loss over
the time scale of minutes or hours mean
significant loss of coolant during a year
and should be avoided accordingly.
However, in the case of the cooling
circuit of a combustion engine under operating
conditions, especially at high operating
temperatures, losing a few drops
of coolant does not have a harmful effect
on the immediate environment because
of the evaporation rate.
Unfortunately, the same cannot be said
of battery cells, modules, and packs. The
harmful effect of even a small amount of
liquid, droplets or as water-bearing vapor,
is much more dangerous to any traction
battery module or pack. There, the liquid
coolant or water vapor can destroy battery
cells or generate a short circuit. The leak
test of cooling circuits of traction battery
packs and for fuel cells must be done with
higher reliability compared to tests of
cooling systems of combustion engines.
The corresponding limiting leakage
rates for such leakage channels are presented
in the paper; the leakage rates
specified here for gas pre-testing are an
order of magnitude significantly below
the detection limit of classical test methods
such as pressure decay or mass flow
leak testing. However, when using modern
test gas methods with forming gas or
helium as the test gas, reliable detection
of critical leakage rates is possible.
This article was written by Marc
Blaufuß, Application Engineer,
article
Leak
Detection Tools, and Daniel Wetzig,
Research Manager, both at Inficon
GmbH (Köln, Germany). This
is a condensed and edited version of
SAE Technical Paper 2022-01-0716. For
more information, visit www.sae.org/
publications/technical-papers. 
Battery & Electrification Technology, December 2022
SilSo Lite 21025
NEW SILICONE FOAM FOR ELECTRONICS & EV BATTERY PACKS
Designing lighter weight components has widely become
a key trend in the Transportation sector to reduce energy
consumption and increase the range of electric vehicles.
CHT's all new Silicone Foam is designed to reduce weight
as well as mitigate thermal runaway and provide protection
from moisture, debris, vibration and shock.
cht-silicones.com
Meet our silicone experts at:
IPC APEX Expo, Booth #1313, 24-26th Jan. 2022
11
http://info.hotims.com/82328-705 https://www.sae.org/publications/technical-papers https://www.sae.org/publications/technical-papers
Automotive Engineering - December 2022

Table of Contents for the Digital Edition of Automotive Engineering - December 2022
