Power battery charging and heating loop, control method thereof and electric vehicle

Abstract

The invention relates to a control method for a charging and heating loop of a power battery. The method is characterized in that after a battery management system BMS is connected with a charger, inthe process that a heat source of a heating device is transitionally switched from a power battery to the charger, when the battery management system BMS detects that the output current of the batteryis 0, a main negative relay is disconnected, and a heating loop is connected; and after the lowest monomer temperature of the power battery is heated to be higher than a set temperature threshold value for stopping heating, the battery management system BMS requests to adjust the charger voltage to be equal to the total voltage of the power battery, no potential difference exists between the twoends of the power battery and the output end of the charger, the main negative circuit breaker is closed, and the heating loop is switched into the charging loop. According to the invention, the electric arc phenomenon during the relay action is avoided, and the adhesion or other fault risks caused by the on-load action of the relay in the heating and charging conversion process are further avoided.

Description

technical field [0001] The invention relates to the technical field of new energy vehicles, in particular to a method for controlling a power battery charging and heating circuit of a new energy electric vehicle. Background technique [0002] In the field of new energy vehicles, the power battery, as a power source, provides electric energy for other high-voltage components of the vehicle, and is one of the core components of new energy vehicles. When the power of the power battery is low, it can be charged by fast charging or slow charging. If the temperature of the power battery is relatively low, the power battery pack needs to be heated first. When the temperature of the power battery is higher than the set temperature threshold Charging is allowed. [0003] The heating control circuit of the power battery generally includes a heating current measuring device, a heating device, a heating fuse, a heating relay, etc. The heating device is attached to the surface of the i...

AI Technical Summary

Problems solved by technology

[0004] In the above solution, when switching from the heating link to the charging link, since the charger has already started to work, when the charging circuit relay is directly closed, it is an action with load, which is prone to arcing, which will affect the life of the relay, and in severe cases will cause the relay to stick , a charging accident or malfunction occurs

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