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The Benefits of Wire Compacting for EV Manufacturing

Electric vehicles (EV) were once a curiosity. Just 4 short years ago, our sister company, AMADA WELD TECH EUROPE was helping to lend its welding expertise in assembling batteries for the first electric motorcycle which circumnavigated the globe in just 80 days. Now, EVs are everywhere; almost every major automotive manufacturer has one or has plans to release one in the next few years.

What is the Challenge?

Today’s electric vehicles need to be powerful, fast and efficient; they need to be able to go farther, faster on a single charge. The cables and connections that make up their “central nervous systems,” so to speak, must be fault free and robust enough to ensure performance throughout the serviceable life of the car. Some of the issues engineers encounter in designing and assembling these all-important cables include thermal management, contact resistance, connector dimensions, mechanical stress load, weight, product lifespan, and the need for cost reductions. In our experience, wire compacting is essential for stranded cable connections.

What is Wire Compacting?

Wire compacting is a process in which stranded wire is compacted and welded into a desired shape in order to better facilitate attachment to other components. This is generally done using resistance welding.

The process looks like this:

How Will Wire Compacting Benefit My Process?

Challenge How Compacting Helps
Contact resistance. When contact resistance increases, current flow is reduced, and heat is generated at the interface, which, over time, weakens cables. As cumulative heat exposure increases, longevity of the electrical system decreases. Compacted wire connections possess reduced contact resistance, which helps to reduce the overall temperature of the electrical system contributing to longevity.
Connection footprint. Stranded wire cables often have frayed ends which need to be gathered together before connecting to a terminal. Wire end sleeves are often used to achieve smaller dimensions and facilitate easy installation but this process is slow and labor intensive. AND adds weight. Wire compacting results in cables free of frayed ends, negating the need for wire end sleeves and resulting in smaller dimensions for installation. This is advantageous particularly as engineers are always looking for ways to reduce the size and weight of installed components. In addition, compacted cables can be welded to terminals whose geometry and package dimensions otherwise render them unsuitable for direct, non-compacted wire connection.
Reduced product lifespan. The cycle of localized heating and cooling of the weld joint causes minute expansion and contraction of the material which, as the material relaxes during cooling, often doesn’t return to its original crimped dimensions, thus reducing the lifespan of the part. The reduced contact resistance of the compacted joint results in lower temperatures, less thermal cycling and, ultimately, improved product lifespan.
Cost reduction – The EV market is becoming extremely competitive and every manufacturer seeks to make more and better product at a lower cost per unit. Wire compacting reduces the need for complicated assemblies that require unnecessary processing steps like organizing frayed wires or adding wire end sleeves. It also reduces cycle time and increases throughput, saving money.
Mechanical stress load. Stresses due to vibrations and G-forces can degrade joints and lead to reduced or failed conductivity. Wire compacting results in more robust connections reducing the potential for problems due to mechanical stress load.

Typical Wire Compacting Images

What Kind of Equipment is Needed?

To achieve the kind of compacting discussed in this blog, you’ll need a resistance welding power supply and a weld head fitted with tooling specifically designed for wire compacting. The exact products selected will depend on many things including the materials you are working with, the size/gauge of the wire to be compacted, the degree of compaction required, and your anticipated duty cycle. Contact us for more specific information.

Category: Resistance Welding