Preheating system for battery of electric vehicle

Abstract

The invention discloses a preheating system for a battery of an electric vehicle. The problem is solved that the activity of the battery of the electric vehicle declines in winter due to the low environmental temperature and then causes decline of the cruising ability. The preheating system for the battery of the electric vehicle is characterized in that a preheating device comprises an external temperature detection unit used for detecting the temperature outside the vehicle and outputting an external temperature detection signal and a control unit which is provided with a floor reference value signal in advance and coupled to the external temperature detection unit; the control unit controls a preheating component to be started or not according to the comparison situation between the external temperature detection signal and the floor reference value signal and a remote control signal of a remote control device; when the external temperature detection signal is lower than the floor reference value signal and the remote control device controls vehicle doors to be unlocked, the control unit controls the preheating component to be started. According to the system, before starting, if the external temperature is lower than a floor reference value, the preheating component is started to conduct preheating on the main lithium battery, so that it is guaranteed that the main lithiumbattery works at a proper environmental temperature.

Description

technical field [0001] The invention relates to electric vehicles, in particular to a battery preheating system for electric vehicles. Background technique [0002] For friends in the north, it seems that more than 20 degrees below zero in winter is very common; however, some electric car owners are worried when winter comes; in winter, the mileage of electric cars will be greatly shortened, which will not only affect us For travel plans, some friends are even reluctant to turn on the heater in order to save electricity, and the temperature inside and outside the car is almost the same. This kind of experience makes people regret the original choice. [0003] Generally speaking, the vast majority of electric vehicles and even electronic digital products currently on the market use lithium-ion batteries, which are what we often call lithium batteries; and the common lithium batteries for electric vehicles are mainly lithium iron phosphate. host. [0004] Like our common ba...

AI Technical Summary

Problems solved by technology

[0005] In a low temperature environment, the battery life of electric vehicles is shortened mainly because the extremely low temperature will affect the activity of lithium compounds; the most common compound in lithium batteries is lithium iron phosphate, and lithium manganate is also included; and these The activity of the compound at different temperatures determines the battery life of our electric vehicle lithium batteries at different temperatures; for example, the most common lithium iron phosphate has very good high temperature resistance, so it can It has the best discharge capacity, but as the temperature decreases, the activity gradually decreases, and the discharge capacity will gradually decrease; especially in the low temperature environment of minus 20 degrees, which is relatively common in Northeast China, it will even be close to 50%; and currently The vast majority of domestic electric vehicles headed by BYD in China use lithium iron phosphate batteries

[0006] Faced with the problem that the charging and discharging power of power lithium batteries is reduced under low temperature conditions, which affects the start-up and power performance of the whole vehicle, major manufacturers mainly adopt two technical means: 1. Adopt the method of starting the vehicle in advance under cold conditions like traditional vehicles. The method of heating the transmitter is to manually start the vehicle in advance, and the battery heating module is activated to heat the battery when certain conditions are met; because the battery is in different ambient temperatures, the temperature dropped by the battery cannot be estimated, resulting in unpredictable early start of the vehicle 2. Start the vehicle, and use the heating module and battery charge and discharge to increase the temperature of the battery itself during vehicle driving. This method will cause battery capacity attenuation and energy recovery rate reduction, which will affect the driving experience of the driver.

[0007] When the electric vehicle is not charged, all the power comes from the lithium battery in the car, so the shrunk lithium battery power is actually mainly consumed in the process of keeping the battery warm or heating; thus resulting in the overall electric vehicle Reduced battery life in winter

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