Overview
A printed circuit board (PCB) is a structure that provides electrical as well as mechanical support to the components within a circuit, which are wired together with copper routes. PCBs are used mostly in electronic devices, ranging from calculators, radios, printers, LED lights, vending machines, all the way to computers, GPS devices, and satellite systems.
PCBs also play a role in the automotive industry, enabling various features that ensure safe and smooth driving experience. There may be PCBs in different areas of the car, which is why they must be able to meet certain standards, such as heat resistance and good reliability. PCBs can be found in vehicle systems such as navigation, entertainment, energy management, and sensors.
Different kinds of PCBs exist for different purposes: rigid, flexible, or rigid-flexible. In this article, we will talk about what flexible circuits are, including two different types, in order to determine which is most suited to your needs.
What are flexible circuits?
It was earlier established that electric vehicles need PCBs; specifically, these use flexible PCBs, or flexible circuits.
In general, flexible circuits are a pattern of conductors on bendable film or layer, which may be made from polyimide (PI) or polyethylene terephthalate (PET). Such circuit boards are required to build a device faster. In EVs, these enable engineers to save space, mold circuits into a vast range of configurations, and ensure greater performance reliability.
Flexible circuits are used in the Battery Management System (BMS), infotainment systems, sensors and control systems, and power distribution, to name a few.
What are flexible printed circuits (FPCs)?
A flexible printed circuit (FPC) has all the characteristics of a flexible circuit, as it is described above. Its flexibility affords it the ability to fit into small and irregularly shaped spaces. In turn, this reduces the weight of the device itself and optimizes thermal management, because the amount of heat to be dissipated is also reduced.
FPCs also have high resistance to vibrations, high temperatures, and atmospheric conditions. These are commonly used in EV battery cell contacting systems, but they are also the most costly component of the current collector assembly.
FPCs are manufactured through a multi-step batch photolithography process that etches copper onto the circuit. This involves using harsh chemicals to dissolve the excess copper, a process that is both time- and energy-consuming and hardly sustainable.
Flexible printed circuits have a high initial cost due to the fact that they are manufactured for very specific applications. They also have a size limitation of 600×600 mm.
What is the flexible die-cut circuit (FDC) technology?
The other, newer type of flexible circuit is called the flexible die-cut circuit (FDC). Pioneered by mobility electrification solutions partner, ENNOVI, FDCs are a more cost-effective, sustainable, and quicker production process for flexible circuits.
Described as a flat, flexible device, FDC technology is produced through reel-to-reel manufacturing, involving fewer processes. It cuts costs by 25 to 50%, and process time by 50%, compared to FPCs.
Whereas FPCs manufacturing makes copper recycling difficult, FDC technology can instantly recycle copper due to the die-cutting process.
This type of circuit has similar performance to FPCs, but unlike them, FDCs do not have a size limitation.
The results of FDC technology have been confirmed through strict tests of dimensions, thermal shock, trace resistance, temperature rise, insulation resistance and high voltage.
What are the applications of FDC technology?
FDC technology has a wide range of applications:
- EVs
ENNOVI’s battery interconnect system for prismatic cells, ENNOVI-CellConnect-Prism is a prime example of FDC technology at work. It enables the smooth integration of individual prismatic cells in order to create bigger battery modules, or advanced cell-to-pack (CTC) or cell-to-chassis (CTC) configurations. It also streamlines processes in a one-stop lamination process that can cut costs by up to 15%. - Commercial transportation: trucks, maritime, air transportation
- Energy storage: wind turbines, solar energy
- Personal mobility: hybrid vehicles, motorized scooters
