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September 2023
Why PCB Cleaning is Critical in the EV Market
By Jason Schwartz, Business Development Manager, KYZEN
ionic contamination from their boards. It is well established that when combining ionic contamination from flux residues with humidity and the elec- trical bias from a live circuit board, electrochemical migration leads to dendritic growth. These dendrites will eventually
T
form a bridge to another area of the board causing a short. Traditionally, the highest reliability circuit boards have been cleaned to prevent these short circuits. Military, avionics, and medical devices are considered high reliability due to the potential loss of life resulting from a failure. Simply put, if the circuit board in a pacemak- er or a flight control system fails someone could die. In contrast, traditional internal
he justification for cleaning hasn’t changed over the last 30 years. PCB as- semblers clean circuit boards to remove
EVs Call for PCBs of Increasing Density However, electric vehicle (EV) startups
drastically changed the role that electronics
electronic control units with specific func- tions, electric vehicles now combine a greater number of control units into fewer printed circuit boards.
These boards tend to have newer
and higher functioning chipsets, often with broader and increasingly complex functions. These boards don’t only control power steering and adaptive cruise control but also pro- vide increasingly complex driver as- sistance that is becoming ever nearer to autonomous driving. Power electronics like DC/AC in-
combustion engine vehicles (ICE) had few, if any, high reliability circuit boards. The advent of engine control units and driver safety/assistance features such as adaptive cruise control created some moderately high reliability requirements.
Heavily populated boards will have different localized thermal profiles during reflow, which can result in unencapsulated ionic residues.
play in the operation of personal and com- mercial vehicles. Where originally vehicles required dozens of independently operating
verters no longer only power simple functions like power windows but provide the main power supply to the electric motor. Battery management systems are required to keep the car operating as well as to extend the range of the vehicle. Failures of these systems are no
longer minor inconveniences but cre- ate potentially serious risks to drivers and passengers including loss of propulsion, autopilot failures and
thermal runaway events, colloquially known as battery fires. Therefore, an increasing
Continued on next page
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