Here John O’Brien, global technologist at PennEngineering®, talks about the changing requirements of the EV sector and how the newly launched ECCB™ PEM eConnect® Contact Bushing is able to provide superior electrical connections, especially for busbars in electric vehicles.
At PennEngineering® we look to be ahead of the industry when it comes to trends and designs, so we can make sure we have a relevant product or technology for when companies, in different markets, are looking for solutions. A fundamental part of these new solutions is that they offer an increased performance perspective or a cost saving – whether from the component level or the assembly.
My role as a technologist is that I work with every company within the PennEngineering® Group – PEM®, Haeger®, Sherex® and PROFIL® – and I focus on the electrical aspect of engineering. A number of years ago we identified as a business that there was going to be a requirement for electrical solutions and that is why we have built a knowledge base and experience within that area, so we can leverage this topic and create new products. This is exactly what we have done with our eConnect® portfolio, especially the ECCB™ PEM eConnect® Contact Bushing, which provides a unique solution for busbar applications within electric vehicles.
When the initial EVs were launched a lot of the high current pathways in the vehicles were done using heavy-duty cables, as they provided great flexibility when fitting the system, but had very limited actual performance. As EVs developed so did the technology and the requirements for a higher current. This led to EV companies looking at the potential of busbars as an alternative, which offered the same performance but were significantly less expensive.
The initial busbars were copper and due to their design would require a significant amount of copper to make them suitable for the EV sector, which would make the vehicles too heavy and expensive. Companies therefore decided to run the busbars warmer, which helped halve the amount of copper needed. Further developments happened to the point where certain busbars could run at up to 10A/mm2, but this led to them getting very hot. However, due to EV batteries also developing there was already a need for a cooling system, which meant it could be used for the busbars, enabling them to run hot whilst being kept slim – reducing costs and weight.
This is where the trend was for a while, but then around 2022 the price of copper reached a point where EV companies started to look at other materials that could be used, such as aluminium, which offered the same performance as copper. Even though twice as much material was required, creating a slight space constraint, the aluminium was still half of the weight of the copper that would be required. This meant it was a win-win scenario, as the copper could be directly replaced with aluminium and it was still possible to make a weight saving, as well as a cost saving.
The only issue with aluminium is it’s very corrosion resistant, as it forms an aluminium oxide layer on the surface extremely quickly – almost instantly. This is bad because it insulates, which is not good for busbars as you want to be able to make contact with the surface. To get around this issue, manufacturers can give the aluminium material a polish with a rough surface, before quickly combining the surfaces, but this is not the most effective. Another option is to electroplate them, with either tin, silver or nickel, but the issue with this is it can prove difficult, it is expensive, and depending on the chemistry used, it is not particularly environmentally friendly.
That is why we introduced the ECCB™ PEM eConnect® Contact Bushing, which can be used to make reliable electrical connections between aluminium busbars, as well as copper, plus PCBs or cable terminals. The ECCB™ PEM eConnect® Contact Bushing uses a high surface area knurl design to pierce the corrosion layer on busbars – creating a consistent electrical current connection without needing to plate the busbar itself. Designed for installation into straight punched holes, without additional surface preparation, the ECCB™ PEM eConnect® Contact Bushing also breaks aluminium and copper oxide layers on busbars for low resistance connections and can be used in panels with sheet hardness HRB 50 / HB 82 or less.
For installation, PennEngineering® can also supply PEM eConnect® current carrying pins, which provide superior electrical connections in applications that demand superior performance from internal components. Available in self-clinching and broaching mounting styles, these installation systems can be used with electric vehicles, including EV charging systems, EV powertrain, EV power distribution, as well as industrial switchgear.
The ECCB™ PEM eConnect® Contact Bushing is a new solution that will provide significant benefits for EV companies looking to optimise the vehicles. It has already been used for some applications and we have data available, including thermal cycling testing and current carrying cycling testing, to show that the product is able to meet the very highest requirements.
Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.
Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.
