By Christoph Steitz DUESSELDORF, Germany (Reuters) – Europe’s top carmaker Volkswagen and oil major BP plan to deepen their electric charging partnership and could expand it to other regions and technologies, their CEOs said on Thursday. The comments reflect increasing efforts by carmakers and energy companies, including utilities and oil firms, to expand charging infrastructure for electric vehicles and tackle the issue of range anxiety – or concern about adequate energy storage – that’s still weighing on demand. To tackle the problem, both groups plan to jointly install 8,000 fast-charging s…