Designed to accelerate the shift to electric cars among other climate goals, the Inflation Reduction Act has in practice made buying such vehicles a lot more complicated.In August, the law ruled out the full tax credit of $7,500 for electric vehicles and plug-in hybrids assembled outside North America. That may make it harder for consumers to take the financial or psychological leap to buy a battery-powered car.The Treasury Department further tightened those rules this week by requiring that a certain percentage of the components and minerals in car batteries are sourced from the United States or in countries that are its trade allies — numbers that will increase over time.Just 11 electric cars from four automakers — Tesla, General Motors, Ford Motor and Volkswagen — now qualify for the full tax credit; several others can qualify for a partial $3,750 cred …