“Although small, bus bar components are numerous, and also critical to the efficiency and durability of xEV batteries, motors, and power electronics,” said Giacomo Parisi, Marketing Director for Automotive Electrification at DuPont. “Our goal is to provide an excellent material for the application, along with assisting customers in their bus bar design and overmolding, to help them achieve their performance and production goals.”

Overmolded bus bars are found in virtually every xEV system. They transfer electrical energy from high-power battery packs to inverters, and inverters to e-motors, while insulating the conductor from ground or other phases. With the right materials, a bus bar can enhance a battery or e-motor energy density, durability, and electrical safety. However, it must be adequately insulated if the battery overheats, a condition known as thermal runaway, to help avoid module-to-module heat propagation.

“Something like only 12% of our plastic waste in the UK is recycled in the UK and we can’t wait for the government. The returns scheme for plastic has just been delayed so it’s probably not gonna happen until 2025, especially with a Tory government.” The outlook is pretty bleak but that’s not stopping Charlie Rudkin-Wilson, who’s taking action into her own hands with Müll Club, a refill shop and a plastic recycling hub in Brockley.

Even though we know so much more about the size and scale of the problem now, there’s still a distinct lack of action. “Funding by central government to councils has reduced by something like 65% since 2010-2019, so all of that money is going to health and education and all of that stuff, understandably, but there’s no money in recycling. I didn’t get any support from the council,” says Charlie. “Councils also, there’s a whole push to be zero waste, to reduce the waste by 2030, and councils will quite proudly say ‘well we don’t send our waste to landfill’ but what they are doing is incinerating, which isn’t a solution. They say it’s safe but they also say the air we breathe is safe and we know that’s not true. And they make money, I think, off the back of that, and they don’t have to pay anybody either to take the waste. So I think it’s easy for them to incinerate for their stats, or for financial reasons, but all that does is ensure that we’ve still got demand on plastic. Then we have to keep making new, and that means we’re still supporting the fossil fuel industry. We don’t have the infrastructure because not enough attention has been paid to it.”

The frustrating thing is that the way Charlie recycles plastic is incredibly simple – the shredding and injection moulding machines she uses come at a cost, as do the product moulds, which are laser cut out of aluminium, but not prohibitively so. Once Charlie has collected the plastic (it’s mainly dropped off in a bin outside the shop, but she has plans to add more of them at Overground stations to make it more convenient for people), she washes it, shreds it, sorts it into different blends based on the colour, and injection moulds it into new items like soap dishes, coasters, combs, and candle holders. It takes about nine minutes for the plastic to be melted and moulded, with the whole process from plastic item to finished product taking around half an hour. “It blows your mind how easy it is, this isn’t some really technical thing, it’s something we can easily be doing in the UK en masse but we’re not,” says Charlie.

At Müll, Charlie works with type 2 (HDPE) and type 5 (PP) plastic, though they can’t be mixed together. Not only do they not melt in the same way, the end plastic product then won’t be able to be recycled, whereas the items made from one individual type can be recycled again. That means if someone is done with one of Charlie’s creations, they can send it back for her to shred down and turn into something else.

“Councils will quite proudly say ‘well we don’t send our waste to landfill’ but what they are doing is incinerating, which isn’t a solution.“

It’s a space where “people can come in during the week, bring their plastic waste, so think yoghurt pots, butter pots, bottle lids, I shred it all up and recycle it into beautiful household items.” Anything that gets dropped up that can’t be turned into new products can be used for people to use containers for the refill store.

Charlie is acutely aware that action has to be taken to address the plastic issue because we as a society have become so reliant on it – something that she lays at the feet of the government and big industry. “Plastic first started being used en masse during WW2, so all of this money went into the infrastructure, and then the war finished and it’s like, we’ve got all of this. And the fossil fuel industry wants it to continue because plastic is made with a by-product of oil and gas,” she explains. “It wasn’t really until the late seventies that people started thinking about where this plastic was going, but I don’t think anything was actually put into place until the nineties.”

Ultimately the goal is to grow and take Müll Club beyond Brockley and South London. “This is a test run in my mind to kind of understand the volumes of plastic, to prove that my idea can work as well because this is all new to me. It’s only a small bit of impact we’re really having right now. For my immediate community, brilliant, we’re really making a difference in terms of our plastic waste but I’d like to scale it so that other communities have the option. It’s about taking control of our waste, so I wanna offer it in more places,” explains Charlie. “The plan is to scale but really have an impact because we can’t wait for the government, especially if the Tories get in again.”

DuPont Mobility & Materials is breaking new ground for manufacturers of xEV components with a combined material-process-service solution for overmolding bus bars with Zytel HTN polyamide (PA) material. Bus bars are a workhorse component essential for distributing power in xEV batteries, motors, and power electronics.

Zytel HTN has been identified as an elegant material solution in this area. For example, safety standards dictate that bus bars maintain a stable orange color indicating high voltage, even after repeated exposure to high heat. Zytel HTN accelerated aging tests show no noticeable color shifts, even at 130°C. It also contributes insulative properties for safer thermal runaway, and easily overmolds onto aluminum or copper, the most common bus bar metals.

When she first opened, it was operating as My Eco Brockley, a refill store, with a mixture of food and household products. Charlie explains that the combination of the cost of living crisis starting to bite and margins getting slimmer and slimmer at the end of last year, she decided to remove the food and focus on toiletries, skincare and detergent refills. With the addition of the recycling hub, she turned the biz into Müll Club.

Charlie has created a range of plastic shred blends, so she can create products in different colourways. The Stacy, named after a friend, features blue shampoo bottles, pink from Vanish bottles, purple laundry liquid containers and yellow from bleach bottles, and is the bestseller. There’s also Broca, named after her local coffee shop where she collects plastic from; Fancy, because the gold bits make it look fancy; Raspberry Ripple, thanks to its pink and white swirls; and Salt House, named after the yoghurt pots that started that blend off.

The word müll means rubbish in German and it’s a nod to her time spent with her mum who lives in Switzerland, where she first started getting serious about sustainability. “And it’s got a smiley face on. Double whammy,” says Charlie.

Leveraging a host of production equipment, lab testing, and engineering capabilities, DuPont has fine-tuned an overmolding process for bus bars that incorporates Zytel HTN material along with robust technical and processing support. Using sophisticated computer-aided analysis tools, DuPont collaborates with customers to reduce manufacturing time and cost yet maintain performance and safety standards.

Additionally, Zytel HTN insulation materials for bus bars resist multiple thermal shock cycles (typically 1000 cycles) at temperatures (-40° to 150°C) normally needed for motors and power electronics applications. This means the material resists cracks after being overmolded onto metal conductors. Further, the material is chemically resistant to the fluids used for thermal management and has a high comparative tracking index (CTI) at elevated temperatures.

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Sustainability has long been part of Charlie’s story. As well as consulting for TV and film companies on how to reduce their carbon footprint, she had plans for a project to make the whole of Broadway Market zero waste, including getting a bubble barrier fitted in the canal to capture the plastic and then recycle it. Once the pandemic hit, she started doing vegetable deliveries by bike and then she had the idea of adding on refills. She cycled past the space on Harefield Road and decided to open up a shop.

The store is now open Friday – Sunday, with Charlie using the space as a recycling hub for the rest of the week, where she makes a range of recycled plastic products and runs workshops where people can come in and have a go themselves. “The whole message is that you bring in your rubbish and then you make something from it,” she says. “I’m quite political in my views and I like making stuff so this works for me, it feels like a new form of activism really.”

DuPont Mobility & Materials will showcase these and other innovations at K 2022 in Düsseldorf, Germany, from Oct. 19 to 26. The company is exhibiting in booth C43 in Hall 6.

As well as selling the recycled plastic products, Charlie also runs workshops where people can come in and have a go at the process themselves, and “for people that do the workshops especially, but also those that come in and have conversations about it, it really changes their view of plastic, like it’s not a single use thing.” Obviously getting as much plastic out of the bin and turned into something useful as possible is important – Charlie has recycled more than 65,000 bottle caps worth of plastic since the autumn of 2022 – it’s also about winning hearts and minds. It’s “more about the conversation, so customers come in and bring it into me instead of the bin, so they’re like ‘I’ve got pink for you’. It’s changing the view so it’s not just a throwaway item, it’s something of value,” says Charlie. “I don’t know how measurable that is but that’s what I want to do, a conversation and mindset change as well as the amount we’re recycling.”