PORTLAND, Ore.–(BUSINESS WIRE)–Powin LLC (Powin), a U.S. based global energy storage integrator and TÜV Rheinland, a global leader in independent testing, inspection, and certification, have expanded their strategic partnership to further enhance safety, compliance, and innovation in the energy storage industry. As part of this expanded collaboration, TÜV Rheinland will provide technical R&D support, product safety certification, and compliance validation for Powin’s proven energy storage