The gap may widen. LMC predicts that China’s total will nearly triple in the next two years, while the rest of the world’s will merely double. That is because, in part, Chinese government regulations will require automakers starting in 2019 to sell ever-increasing numbers of electric cars and plug-in hybrids if they want to keep selling gasoline cars. China has also begun research on imposing a rule to ban the sale of internal combustion cars someday.

“China is and will be the largest consumer and producer of electric vehicles in the world,” said Bill Russo, the founder and chief executive of Automobility, a Shanghai consulting firm. “If Tesla hopes to compete as a global electric vehicle maker, it must tap the manufacturing and supply footprint of China in order to compete globally.”

China has the steepest barriers to automotive trade of any large market in the world, making it difficult to compete in the Chinese market without producing in the country. Beijing has been able to retain steep tariffs and other obstacles to imports because it insisted that it was a developing country when it entered the World Trade Organization in 2001.

The W.T.O. has allowed developing countries to retain much higher trade barriers than industrialized countries, on the theory that they have infant industries that may not have grown big enough to withstand global competition. Today, however, China has the world’s largest auto industry.

China charges a tariff of 25 percent on imported cars, compared with 2.5 percent in the United States and 9.8 percent in the European Union. China also has a 17 percent value-added tax — a kind of sales tax — that is charged not only on the price of the car but also on the tariff, so that the taxes are effectively compounded.

Unlike these taxes, the costs of shipping a car across the Pacific are tiny. They can be as little as 1 percent of the cost of a high-priced model like Tesla’s offerings. “Shipping costs are usually not a big deal — it is the 25 percent tariff” that keeps out imports, said Yale Zhang, the managing director of Automotive Foresight, a Shanghai consulting firm.

Robert Lighthizer, the United States trade representative, has expressed concern about China’s trade practices. President Trump is set to visit Beijing from Nov. 8 to 10, but China has shown little sign of willingness to negotiate on sectors that it regards as strategic imperatives, and electric cars are one such industry.