Overview
Every electric vehicle needs a printed circuit board (PCB), upon which electronic components are wired into a single circuit that allows electric current to pass between them. While some are made with rigid materials, other PCBs are made with flexible materials.
Flexible circuits, as they are called, will be the main topic in this article.
A flexible circuit is an arrangement of conductors on bendable film that serves as the insulating base layer. Especially in EVs, flexible circuits are necessary to keep running various functions, such as anti-lock brakes, infotainment systems, and managing individual cells in the battery pack.
What are the features of PCBs in electric vehicles?
In order to have a fuller appreciation of ENNOVI’s flexible die-cut circuit technology, one must first understand what printed circuit boards are.
Printed circuit boards in general, are space-savers due to their light and compact forms. They are resistant to vibrations and shocks, tolerate varying temperatures, and tend to have a long lifespan (up to 20 years). PCBs are also used in an EV’s Battery Management System (BMS), therefore, including energy management among one of its functions.
What are the features of a flexible printed circuit (FPC)?
Flexible circuits (also called “flex circuits” or “flexible PCBs”), as the name suggests, are made to fit the electronic device–in this case, the EV. In addition to being lightweight and thin, it can fit into spaces of varying shapes and sizes. FPCs are defined as having conductive traces made from copper sheets etched on substrate, as well as high wiring density.
They are produced through a batch photolithography process involving numerous steps, which include etching the copper traces. It uses harsh chemicals in order to shed excess copper, a process that takes time and energy and poses challenges for recycling.
ENNOVI’s Flexible Die-Cut Technology (FDC): what is it and how is it different?
FPCs are often the material of choice for EV battery cell contacting systems, but ENNOVI, a trusted name in mobility electrification solutions, has come up with the latest innovation in flexible circuit production.
Given that FPCs are usually the most expensive component in the current collector assembly, flexible die-cut circuit (FDC) technology provides the market with a less expensive and environmentally friendly alternative. It is a flat, flexible device that has a shorter manufacturing process with 25 to 50% less in costs, and can recycle clean copper waste material.
What are the main features of FDC?
Here are some of the features of the flexible die-cut circuit:
Dielectric materials
Flexible die-cut circuits provide two substrate options: polyimide (PI) and polyethylene terephthalate (PET).
PI has excellent flexibility, tensile strength, thermal conductivity, and chemical resistance. Meanwhile, PET also has good flexibility as well as high chemical and moisture resistance.
FDC technology also offers cold and hot lamination processes.
Traces
High-precision die-cutting is done ensuring tight tolerances, while continuous copper traces provide a reliable signal. The double stack layer traces have the capability to enhance packaging efficiency.
Fuses
FDC technology provides built-in fuse traces or surface mount (SMT) fuses, depending on what the customer needs.
Other features include: thermal sensors, which uses SMT and reflow soldering processes to add off-the-shelf negative temperature coefficient (NTC); current collector tabs, made of nickel soldered to copper traces to meet tight packaging space requirements and to achieve reliable signals; and connectors that are compatible with copper traces, as well as solder connector tabs to FDC copper traces.
What are the applications of FDC technology?
FDC technology is used across various industries: personal mobility, commercial transport, energy storage, and EVs.
In fact, FDC technology is used in one of ENNOVI’s battery cell contacting systems, ENNOVI-CellConnect-Prism.
This battery interconnect system enables smooth integration of individual prismatic cells to form larger battery modules, or advanced cell-to-pack (CTP) and cell-to-chassis (CTC) configurations. It combines the processes into a one-stop lamination process, saving costs by up to 15%.
By integrating voltage and temperature sensing into the assembly, traditional insulation methods are no longer needed and materials are used wisely and efficiently.
This streamlining enables the interconnect system to remove inefficiencies and expedite battery pack production, while improving materials usage and reducing costs.