PFI:AIR - TT: Novel High Temperature and High Energy Density Polycarbonate/Nylon Multilayer Films for Electric Vehicles Applications

该PFI：AIR技术翻译项目的重点是翻译凯斯西储大学（CWRU）发现的多层介电薄膜技术，以满足电动汽车（EDV）对高性能和低成本聚合物薄膜电容器的需求。EDV的优势在于在人口稠密的城市中全面减少温室气体排放和污染。电动汽车需要一个电力电子系统来操作最终驱动汽车的电机。 电力电子系统需要直流链路电容器来响应来自驱动器的速度命令来适当地控制电机。 EDV的电力电子设备中的当前DC链路电容器使用双轴取向聚丙烯（BOPP）膜。然而，BOPP薄膜电容器具有相对较低的能量密度和85°C的低温额定值。因此，大体积的BOPP薄膜电容器和水冷却系统在目前的EDV中是必要的，这导致电力电子单元的高总成本。为了克服这种经济上的缺点，非常希望开发新的高性能电容器膜，其具有更高的能量密度并且可以在高达150 °C的温度下有效地操作，从而可能完全消除冷却系统并且导致更小的尺寸和质量的系统。CWRU发明了一种独特的多层介电膜技术。在该技术中，高温、高击穿强度和低损耗介电聚合物（例如，聚碳酸酯，PC）与高能量密度聚合物（例如，聚（偏二氟乙烯），PVDF）使用多层共挤出技术制成层状构造。研究发现，高能量密度，高温耐受性，和低损耗的介电性能可以同时在一个系统中实现。因此，这种多层膜技术的创新之处在于，无需合成和开发新的聚合物，只需采用市售聚合物即可获得新的介电材料。因此，可以预期较短的商业化途径。在现有的PC/PVDF多层膜的基础上，本项目旨在用一类更便宜，但仍具有高能量密度的偶数尼龙取代PVDF，用于具有高温PC的多层膜。初步结果表明，PC/尼龙多层膜也可以实现高能量密度、耐高温和低损耗。在这个项目中，PFI AIR团队，由CWRU和两个小企业组成：PolymerPlus，LLC和SB Electronics，Inc. (SBE)提出将PC/尼龙多层介质膜技术转化为EDV的高温和高性能DC链路电容器。具体而言，CWRU将开展薄膜级基础研究，以确定PC/尼龙多层薄膜的最佳配方。PolymerPlus将使用这种配方，并将薄膜生产规模扩大到无摩擦薄膜卷。经过适当的金属化后，PolymerPlus将向SBE提供金属化薄膜卷，以包装成原型薄膜电容器。该团队将测试这些电容器原型与BOPP电容器相比的性能。该研究项目将为研究生和本科生提供理想的培训机会，因为他们可以与两家小型企业的专家合作，学习技术翻译和商业化途径。如果成功，该团队将能够使用该项目的成果，并与EDV制造商建立联系，以进一步商业化多层介电薄膜技术。

This PFI: AIR Technology Translation project focuses on translating the multilayer dielectric film technology discovered at Case Western Reserve University (CWRU) to fulfill the need of high performance and low cost polymer film capacitors for electric drive vehicles (EDVs). The advantage of EDVs lies in the overall reduction of greenhouse gas emissions and pollution in heavily populated cities. Electric drive vehicles require a power electronics system to operate the motor that ultimately moves the car. The power electronics system requires DC-link capacitors to properly control the motor in response to speed commands from the driver. Current DC-link capacitors in the power electronics of EDVs use biaxially oriented polypropylene (BOPP) films. However, BOPP film capacitors have relatively low energy density and a low temperature rating of 85°C. Thus, a large volume of BOPP film capacitors and a water-cooling system are necessary in present EDVs, contributing to a high overall cost of the power electronics unit. To overcome this economic disadvantage, it is highly desired to develop new high performance capacitor films, which have a higher energy density and can operate efficiently up to 150 °C, thus potentially eliminately the cooling system entirely and resulting in a smaller size and mass system.Supported by the NSF Science and Technology Center, Center for Layered Polymeric Materials (CLiPS), a unique multilayer dielectric film technology was invented at CWRU. In this technology, a high temperature, high breakdown strength, and low loss dielectric polymer (e.g., polycarbonates, PC) is multilayered with a high energy density polymer (e.g., poly(vinylidene fluoride), PVDF) into a layered configuration using the multilayer coextrusion technique. It is found that high energy density, high temperature tolerance, and low loss dielectric properties can be achieved simultaneously in one system. Therefore, the innovation of this multilayer film technology lies in the fact that without synthesizing and developing new polymers, new dielectric materials can be achieved simply by employing commercially available polymers. Consequently, a shorter commercialization pathway can be anticipated. On the basis of existing results on PC/PVDF multilayer films, this project aims to replace PVDF with a class of cheaper, but still high energy density, even-numbered nylons in multilayer films with high temperature PC. Preliminary results indicate that high energy density, high temperature tolerance, and low loss can also be achieved in the PC/nylon multilayer films.In this project, a PFI AIR team, comprised of CWRU and two small businesses: PolymerPlus, LLC and SB Electronics, Inc. (SBE), proposes to translate the PC/nylon multilayer dielectric film technology into high temperature and high performance DC-link capacitors for EDVs. Specifically, CWRU will carry out film-level fundamental research to determine the optimal formulation of the PC/nylon multilayer films. PolymerPlus will use this formulation and scale up the film production into wrinkle-free film rolls. After appropriate metallization, PolymerPlus will supply the metallized film rolls to SBE to package into prototype film capacitors. The performance of these capacitor prototypes in comparison with BOPP capacitors will be tested by the team. This research project will offer ideal training opportunities for both graduate and undergraduate students because they can work with experts in the two small business companies and learn the technology translation and commercialization pathways. If successful, the team will be able to use the outcomes from this project and connect to EDV manufacturers for further commercialization of the multilayer dielectric film technology.