A method for starting and power distribution control of hydrogen fuel under low temperature conditions

Abstract

The present invention discloses a method for starting and controlling power distribution under low temperature conditions of hydrogen fuel, comprising the following steps: S1: after the vehicle is powered on with high voltage, the current temperature T of the lithium battery is determined. BAT and the allowable charging power P B , determine whether the hydrogen fuel is started normally; S2: when the vehicle speed is 0, judge the current system output power state of the vehicle in real time, and perform corresponding power distribution control; S3: perform power distribution control according to the comprehensive performance of the lithium battery and the power change of the vehicle. In the hydrogen fuel system vehicle, the present invention distributes power to the controllable equipment when the dual power sources fully enter the normal working state during low-temperature startup. The power distribution startup method is adopted to avoid the rapid consumption of lithium battery power, speed up the start of hydrogen fuel, supplement the discharge power of lithium battery, reach a relative balance state, and avoid overcharging and over-discharging of lithium battery at low temperature during startup power distribution and adjustment, thereby improving the service life of lithium battery.

Description

Technical Field

[0001] The invention relates to a hydrogen fuel vehicle, and in particular to a method for starting and controlling power distribution under low-temperature conditions of hydrogen fuel. Background Art

[0002] With the development of hydrogen fuel technology, hydrogen fuel vehicles are becoming more and more widely used, and more and more northern regions are beginning to use hydrogen fuel new energy vehicles. During use, it was found that low temperature environments have serious restrictions on the use of hydrogen fuel vehicles. From the perspective of the power source of hydrogen fuel vehicles, the vehicle uses a hybrid power source of hydrogen fuel and lithium batteries. In low temperature environments, lithium batteries cannot receive continuous charging current. In low temperature environments and when lithium batteries are also at low temperatures, the hydrogen fuel system cannot be started at any time, otherwise it will cause the lithium battery to be overcharged, which will seriously affect the life of the lithium battery, and more seriously, it will cause safety hazards to the lithium battery.

[0003] Therefore, in response to vehicle startup and power control in low-temperature environments, a control strategy for hydrogen fuel in low-temperature environments is developed in combination with the temperature characteristics and control methods of lithium batteries. This is used to solve the problem of uneven power source distribution in hydrogen fuel vehicles, excessive discharge of lithium batteries causing malfunctions or damage due to continuous discharge, and to avoid limiting the normal operation of the vehicle due to insufficient power.

[0004] In the low-temperature starting control of hydrogen fuel, the study found that the matching combination of hydrogen fuel starting output and vehicle power distribution control can effectively solve the power source distribution problem of hydrogen fuel vehicles in low-temperature applications. Summary of the invention

[0005] The purpose of the present invention is to provide a method for starting and controlling power distribution of hydrogen fuel under low temperature conditions, solve the problem of starting and controlling power of hydrogen fuel in low temperature environment, solve the low temperature starting strategy of lithium battery and hydrogen fuel, and avoid the continuous discharge of lithium battery without replenishment, causing over-discharge, over-current and other problems.

[0006] The technical solution of the present invention is:

[0007] A method for starting and controlling power distribution of hydrogen fuel under low temperature conditions, comprising the steps of:

[0008] S1: After the vehicle is powered on with high voltage, the current temperature of the lithium battery T BAT and the allowable charging power P B , determine whether the hydrogen fuel is started normally;

[0009] S2: When the vehicle speed is 0, the system output power state of the current vehicle is determined in real time, and corresponding power distribution control is performed;

[0010] S3: Power distribution control is performed according to the comprehensive performance of the lithium battery and the vehicle power changes.

[0011] Preferably, the method for judging whether the hydrogen fuel and power distribution control are started normally in step S1 is:

[0012] (1) According to the current lithium battery temperature T BAT Determine the current performance of the lithium battery;

[0013] (2) Based on the current vehicle output power P and the current allowable discharge power P of the lithium battery B Determine the available power of the system;

[0014] (3) When T BAT If the temperature is lower than the set temperature, the lithium battery will be heated and the temperature of the lithium battery will start to rise;

[0015] (4) Hydrogen fuel starting output power is P F , the power battery heating power is P1, if P F >P1+P, then hydrogen fuel will not be started. If P F ≤P1+P, start hydrogen fuel;

[0016] (5) If the lithium battery heater is turned on but the hydrogen fuel starting conditions are still not met, turn on the vehicle electric heater and judge P B change;

[0017] (6) The vehicle electric heating power is P2, when P1+P2+P+P B ≥P F , hydrogen fuel start, P1+P2+P+P B <P F , the hydrogen fuel will not be started until the start conditions are met.

[0018] Preferably, step S3 performs a power distribution control method according to the comprehensive performance of the lithium battery and the vehicle power change, including:

[0019] (1) When the ambient temperature is lower than the set temperature, different electrical equipment can be allocated and controlled to achieve power balance and prevent continuous overcurrent of the lithium battery;

[0020] (2) The lithium battery continues to heat up. When the lithium battery allows charging power P B ≥ Maximum power of hydrogen fuel P F , control the lithium battery heating to shut down;

[0021] (3) When hydrogen fuel can control the output power normally, the vehicle electric heating allows normal start and stop.

[0022] The advantages of the present invention are:

[0023] The hydrogen fuel low temperature start-up and power distribution control method of the present invention distributes power to controllable devices on hydrogen fuel system vehicles when dual power sources are fully in normal working state during low temperature start-up. The power distribution start-up method is adopted to avoid rapid consumption of lithium battery power, accelerate hydrogen fuel start-up, supplement lithium battery discharge power, and achieve a relative balance state. During the start-up power distribution and adjustment, overcharge and over discharge of lithium batteries at low temperatures are avoided, thereby increasing the service life of lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0025] Figure 1 The power distribution of the present invention is related to the opening of hydrogen fuel;

[0026] Figure 2 The relationship between the continuous charging power and temperature allowed for the lithium battery of the present invention;

[0027] Figure 3 This is a flow chart of the startup and power distribution control method under low temperature conditions of hydrogen fuel. DETAILED DESCRIPTION

[0028] The hydrogen fuel low temperature start-up and power distribution control method proposed in the present invention mainly solves the problem that when the lithium battery is at a low temperature and does not allow continuous charging, and the lithium battery power needs to be maintained, the hydrogen fuel is started in time according to the current vehicle power distribution to supplement the vehicle power source. Figure 1 and 2 As shown, the relationship between power distribution and hydrogen fuel opening, and the relationship between lithium battery continuous charging power and temperature;

[0029] The hydrogen fuel low temperature startup and power distribution control method of the present invention comprises the following steps:

[0030] S1: After the vehicle is powered on with high voltage, the current temperature of the lithium battery T BAT and the allowable charging power P B , determine whether the hydrogen fuel is started normally;

[0031] S2: When the vehicle speed is 0, the system output power state of the current vehicle is determined in real time, and corresponding power distribution control is performed;

[0032] The method for judging whether the hydrogen fuel and power distribution control are started normally in steps S1 and S2 is:

[0033] (1) According to the current lithium battery temperature T BAT Determine the current performance of the lithium battery;

[0034] (2) Based on the current vehicle output power P and the current allowable discharge power P of the lithium batteryB Determine the available power of the system;

[0035] (3) When T BAT If the temperature is lower than the set temperature, the lithium battery will be heated and the temperature of the lithium battery will start to rise;

[0036] (4) Hydrogen fuel starting output power is P F , the power battery heating power is P1, if P F >P1+P, then hydrogen fuel will not be started. If P F ≤P1+P, start hydrogen fuel;

[0037] (5) If the lithium battery heater is turned on but the hydrogen fuel starting conditions are still not met, turn on the vehicle electric heater and judge P B change;

[0038] (6) The vehicle electric heating power is P2, when P1+P2+P+P B ≥P F , hydrogen fuel start, P1+P2+P+P B <P F , the hydrogen fuel will not be started until the start conditions are met.

[0039] S3: Power distribution control is performed according to the comprehensive performance of the lithium battery and the vehicle power change, including:

[0040] (1) When the ambient temperature is lower than the set temperature, different electrical equipment can be allocated and controlled to achieve power balance and prevent continuous overcurrent of the lithium battery;

[0041] (2) The lithium battery continues to heat up. When the lithium battery allows charging power P B ≥ Maximum power of hydrogen fuel P F , control the lithium battery heating to shut down;

[0042] (3) When hydrogen fuel can control the output power normally, the vehicle electric heating allows normal start and stop.

[0043] like Figure 3 As shown, the control method design of the present invention combines the low temperature performance of lithium batteries and the vehicle power control strategy to control the start-up and power load change of hydrogen fuel. The lithium battery power decreases rapidly or even runs out of power due to continuous discharge at low temperatures. The power distribution of the vehicle when starting at low temperatures can effectively supplement the power loss caused by non-driving power. This enables the power of the power battery to reach a relative balance and avoids excessive discharge.

[0044] 1. In a low temperature environment, after the vehicle is started, the lithium battery temperature is obtained first, and the temperature range, power and current allowable charging and discharging power of the lithium battery are judged;

[0045] 2. Control the distribution of vehicle equipment and make real-time judgment on the system discharge power. When the discharge power meets the hydrogen fuel start-up conditions, start the hydrogen fuel;

[0046] 3. According to the change of lithium battery charging power SOP and vehicle operation power demand, adjust the hydrogen fuel output power PF to achieve power balance;

[0047] 4. When operating in low temperature environment, lithium battery P B Return to normal, meet the set conditions, and control power distribution normally.

[0048] The power distribution control method of the present invention is mainly based on the fact that hydrogen fuel cannot be directly started when the lithium battery is at low temperature. The lithium battery needs to be heated first. Otherwise, the output power of hydrogen fuel is greater than the discharge power of the vehicle. Charging the lithium battery will cause overcharging, resulting in irreversible damage, and serious safety accidents.

[0049] When the vehicle is in a low temperature environment, the lithium battery cannot be charged, and the vehicle needs to discharge continuously to operate. Therefore, in the absence of any power supplement, the power of the lithium battery will continue to decrease. The lithium battery will affect driving due to continuous discharge and cause power loss.

[0050] After implementing the low-temperature power distribution control strategy for hydrogen fuel vehicles, the hydrogen fuel is started to output power to the vehicle based on the change in system discharge power after power distribution. The power load is changed based on the change in the allowable charging power of the lithium battery, and the power output is adjusted in real time to replenish the lithium battery. Ultimately, the lithium battery power will reach a dynamic balance to maintain the lithium battery power at a high level and meet the power requirements of cold starting in continuous low-temperature environments.

[0051] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any modifications made according to the spirit of the main technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling power distribution of hydrogen fuel at low temperature, characterized in that: Includes steps: S1: After the vehicle is powered on with high voltage, the current temperature of the lithium battery T BAT and the allowable charging power P B , determine whether the hydrogen fuel is started normally; S2: When the vehicle speed is 0, the current vehicle output power P is determined in real time, and corresponding power distribution control is performed; S3: Power distribution control is performed according to the comprehensive performance of the lithium battery and the vehicle power change; The method for judging whether the hydrogen fuel and power distribution control are started normally in steps S1 and S2 is: (1) According to the current lithium battery temperature T BAT Determine the current performance of the lithium battery; (2) Based on the current vehicle output power P and the current allowable charging power P of the lithium battery B Determine the available power of the system; (3) When T BAT If the temperature is lower than the set temperature, the lithium battery will be heated and the temperature of the lithium battery will start to rise; (4) Hydrogen fuel starting output power is P F , the power battery heating power is P1, if P F >P1+P, then hydrogen fuel will not be started. If P F ≤P1+P, start hydrogen fuel; (5) If the lithium battery heater is turned on but the hydrogen fuel starting conditions are still not met, turn on the vehicle electric heater and judge P B change; (6) The vehicle electric heating power is P2, when P1+P2+P+P B ≥P F , hydrogen fuel start, P1+P2+P+P B <P F , the hydrogen fuel will not be started until the start conditions are met; Step S3: According to the comprehensive performance of the lithium battery and the change in vehicle power, the power distribution control method includes: (1) When the ambient temperature is lower than the set temperature, different electrical equipment can be allocated and controlled to achieve power balance and prevent continuous overcurrent of the lithium battery; (2) The lithium battery continues to heat up. When the lithium battery allows charging power P B ≥Hydrogen fuel starting output power P F , control the lithium battery heating to shut down; (3) When hydrogen fuel can control the output power normally, the vehicle electric heating allows normal start and stop.

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