Power battery high-voltage system and control method

The invention discloses a power battery high-voltage system and a control method. The high-voltage system comprises a power battery connected in series in the high-voltage system, a main positive relay, a quick charging relay, a quick charging connector used for being connected with a charging pile, and a main negative relay, the high-voltage load is connected to the two ends of the high-voltage connector, the pre-charging loop is connected with the main positive relay in parallel, and the high-voltage load comprises a heater; the positive electrode of the high-voltage connector is connected between the main positive relay and the fast charging relay, and the negative electrode of the high-voltage connector is connected with the negative electrode of the fast charging connector. According to the invention, the quick charging relay and the main positive relay are changed from a parallel connection mode to a series connection mode, a new high-voltage electrical system topology scheme is formed, a pre-charging f