Some suppliers of busbars and interconnects France Interplex +33 3 8148 3400 www.interplex.com Mersen +33 1 4691 54 00 www.mersen.com Germany BASF +49 621 600 www.basf.com Wafios +49 7121 1460 www.wafios.com USA American Power +1 800 759 7833 www.american-power.com Amphenol +1 203 265 8900 www.amphenol.com Celanese +1 972 443 4000 www.celanese.com CelLink – www.cellinktechnologies.com Cognex Corporation +1 855 426 4639 www.cognex.com Eaton Corporation +1 440 523 5000 www.eaton.com Molex +1 800 786 6539 www.tools.molex.com Wiegel +1 630 595 6550 www.wiegel.com Vietnam Prostech +84 984 695 398 www.prostech.vn 70 September/October 2023 | E-Mobility Engineering we can use a combination of methods.” He adds that one emerging trend is for long busbars known as backbones made from wire measuring 40 x 6 mm thick or 45 x 4 or 5 mm and up to 2 m long. A set might include five to 10 of these mounted close to each other. At the same time, the new architectures create a demand for the design of flexible busbars and coextruded long busbars that meet the needs of CTP and CTC designs. This will mean that suppliers will need to work with customers to explore material solutions or new busbar designs. “Suppliers will have to be extremely flexible, even when they want to optimise manufacturing efficiency by making millions of just one type of part,” the chemistry and specialty materials company’s expert says. If anything, materials suppliers will perhaps have to be even more flexible, as well as being very familiar with the advantages and challenges of the different types of architectures. “We need to speak the technical language of our customers, and understand what they want to achieve, so that their projects can be rapidly developed,” he says. “So the need for expertise across multiple battery architectures is a challenge throughout the supply chain, at every level.” Moving heat Electrical conductors in batteries and around the powertrain are of growing importance to thermal management, thanks to their ability to conduct heat as well as current. That is leading, for example, to busbars that are larger than they would be if their current capacity was the single factor that went into their sizing. Increasing the cross-section is also a simple way of reducing resistance and therefore heat generation in a busbar, further aiding thermal management. The CNC bending specialist started with round wire, but has since developed multiple dedicated machines to handle rectangular material. “We see a trend to bigger cross-sections and greater height-to-width ratios, so we have developed a bigger bending machine,” one of the company’s experts says. “Our first machine was able to bend wire of up to 150 mm² in cross-section, but the new one can handle 300 mm².” The external dimensions of this larger wire are 51 x 5 mm, requiring large machines to bend them rapidly and accurately into shape. The downsides of larger conductors, argues the expert from the chemicals company, are additional cost, weight and bulk that might be undesirable in many designs. “Those are good reasons to find other means of heat dissipation,” the company’s expert says. “This problem could even get worse if the material chosen for busbars is aluminium instead of copper, because aluminium has a lower electrical conductivity, so the heat generation would be higher.” Ideas about how to overcome this problem include the use of thermally conductive adhesives to dissipate excess heat onto a metal housing, for example. Incorporating conductors into thermal management strategies brings opportunities to capitalise on new battery pack materials such as advanced thermoplastics. In designs where the metallic conductor can be cooled by a fluid, or indirectly cooled through a thermally conductive thermoplastic, there are multiple avenues to improve designs for thermal management, notes the chemistry and specialty materials company’s expert. “Thermally conductive thermoplastics help provide electrical insulation and thermal conductivity to conductors This battery assembly system features laminated busbar technology with integrated monitoring of key parameters including temperature and voltage to inform the BMS (Courtesy of Mersen)
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