阅读说明：本技术 车用燃料电池的能量分配方法 (Energy distribution method for vehicle fuel cell ) 是由 欧阳梅 邓承浩 周安健 喻成 余富勇 刘建才 于 2020-06-28 设计创作，主要内容包括：本发明公开的车用燃料电池的能量分配方法,当蓄电池的SOC达到最低限值时,优先以燃料电池次高效减少工作区启动燃料电池,使电池快速充电至SOC<Sub>中</Sub>,再以高效区内选择最接近整车需求功率的点启动燃料电池给电池充电,燃料电池给蓄电池的充电功率较少,降低了化学能和电能的二次转化,提高了经济性；同时解决了蓄电池长期低于SOC<Sub>min</Sub>阶段,动力系统不能满足整车需求的状况。(The invention discloses an energy distribution method of a vehicle fuel cell, when the SOC of a storage battery reaches the lowest limit value, the fuel cell is started by preferentially reducing a work area with low efficiency of the fuel cell, so that the battery is rapidly charged to the SOC In Then, a point closest to the power required by the whole vehicle is selected in the high-efficiency area to start the fuel cell to charge the battery, the charging power of the fuel cell to the storage battery is low, the secondary conversion of chemical energy and electric energy is reduced, and the economy is improved; simultaneously solves the problem that the storage battery is lower than the SOC for a long time ｍｉｎ And stage, the power system cannot meet the requirement of the whole vehicle.)

1. A method for distributing energy to a fuel cell for a vehicle, characterized by: the vehicle meets the following requirements in the driving process:

P_vehicle＝P_cell+P_fc；

wherein P is_vehicleFor the power demand of the vehicle, P_cellFor output of power from the accumulator, P_fcOutputting power for the fuel cell;

dividing the output power interval of the fuel cell into three areas, namely an area A, an area B and an area C from low to high, wherein the area A is a low-efficiency working area of the fuel cell, the area B is a high-efficiency working area of the fuel cell, and the area C is a low-efficiency reducing working area of the fuel cell; the maximum value of the A zone is the lowest power point P of the starting fuel cell_fclowThe maximum value of the B zone is the transition output power P of the BC zone of the fuel cell_fcbcThe maximum value of the C area is the maximum output power P of the fuel cell_fcmax；

When P is present_vehicle<P_fclowWhen the vehicle is not in an over-discharge state, the storage battery outputs power to supply power to the vehicle;

when P is present_fclow<P_vehicle<P_fcmaxWhen the vehicle is running, the fuel cell outputs power to power the vehicle;

when P is present_vehicle>P_fcmaxAnd the output power of the storage battery and the fuel cell jointly supplies power to the vehicle.

2. The power distribution method for a vehicle fuel cell according to claim 1, characterized in that:

setting the upper charging limit SOC of the storage battery according to the charging and discharging performance of the storage battery_maxAnd over-discharge threshold SOC of the battery_minWherein SOC is_min<SOC_max；

When P is present_vehicle<P_fclowWhen the temperature of the water is higher than the set temperature,

if the storage battery SOC<SOC_minFirst, greater than P_fclowIs less than or equal to P_fcbcThe power of the fuel cell is started to meet the power demand of the vehicle, and the redundant energy charges the storage battery to reach the SOC_max；

If the storage battery SOC>SOC_minAnd only the output power of the storage battery is used for supplying power to the vehicle.

3. The power distribution method for a vehicle fuel cell according to claim 2, characterized in that:

when P is present_fclow<P_vehicle≤P_fcbcIf the SOC of the storage battery<SOC_minFirst, greater than P_fcbcThe power starting fuel cell meets the vehicle power supply requirement, and the storage battery is charged to SOC in a redundant manner_max。

4. The power distribution method for a vehicle fuel cell according to claim 3, characterized in that:

when P is present_fcbc<P_vehicle≤P_fcmaxWhen the battery is in SOC<SOC_minAt a constant P_fcmaxThe power of the fuel cell is started to meet the power supply requirement of the vehicle, and the storage battery is charged to the SOC to reach the SOC_max。

5. The power distribution method for a vehicle fuel cell according to claim 4, characterized in that:

when P is present_fcmax≤P_vehicleAnd in time, only the fuel cell is started to discharge, so that the power supply requirement of the vehicle is met.

6. The power distribution method for a vehicle fuel cell according to claim 2, characterized in that:

the storage battery is also provided with a charging working condition value SOC_InWherein, SOC_min≤SOC_In≤SOC_max(ii) a Fuel cell sets its maximum efficiency point power P_fceffmaxWherein P is_fclow<P_fceffmax<P_fcbc；

When P is present_vehicle<P_fclowWhen the temperature of the water is higher than the set temperature,

if the storage battery SOC<SOC_minThe fuel cell is first charged with P_fcbcThe fuel cell is started to meet the power demand of the vehicle, and the redundant energy charges the storage battery to the SOC_InThen switch to P_fceffmaxContinuously charging the storage battery to the SOC_max；

If the storage battery SOC>SOC_minAnd only the output power of the storage battery is used for supplying power to the vehicle.

7. The power distribution method for a vehicle fuel cell according to claim 3, characterized in that:

the storage battery is also provided with a charging working condition value SOC_InWherein, SOC_min≤SOC_In≤SOC_max；

When P is present_fclow<P_vehicle≤P_fcbcIf the SOC of the storage battery<SOC_minThe fuel cell is first charged with P_fcmaxStarting the fuel cell to meet the vehicle power demand and charging the battery to SOC_InThen switch to P_fcbcContinuously charging the storage battery to the SOC_max。

8. The power distribution method for a vehicle fuel cell according to any one of claims 1 to 7, characterized in that: when P is present_vehicle<At 0, only the battery is started and charged.

Technical Field

The invention belongs to the technical field of new energy automobiles, and particularly relates to an energy distribution method of a vehicle fuel cell.

Background

A Fuel Cell Electric Vehicle (FCEV) is a Vehicle in which electricity generated by a Fuel Cell is supplied to a motor to drive wheels of the Vehicle. Fuel cell vehicles can be divided into two basic types, one being an FCEV powered solely by fuel cells and the other being a FCEV powered by a fuel cell battery hybrid. Because the hybrid power can carry out secondary utilization on energy, the manufacturing cost of the storage battery is much lower than that of a fuel cell, and the storage battery can provide larger instantaneous output power when starting and accelerating, so that the hybrid power has the advantages of energy conservation and cost compared with an FCEV (hybrid electric vehicle) which takes the fuel cell as power only.

For a hybrid electric vehicle with two power sources, namely a storage battery and a fuel cell, how to exert the advantages of the hybrid electric vehicle is most critical to solve the problem of energy distribution between the fuel cell and the storage battery. Therefore, a reasonable energy distribution control strategy needs to be designed, so that the deep charging and discharging of the storage battery are prevented, frequent charging and discharging are avoided, the service life of the battery is delayed, and the energy efficiency of the whole power system is improved.

Disclosure of Invention

The invention discloses an energy distribution method of a vehicle fuel cell, which not only delays the service life of the cell, but also improves the energy efficiency of the whole power system, thereby solving the problem of energy distribution between the fuel cell and a storage battery.

The invention discloses an energy distribution method of a vehicle fuel cell, which meets the following requirements in the vehicle driving process:

P_vehicle＝P_cell+P_fc；

wherein P is_vehicleFor the power demand of the vehicle, P_cellFor output of power from the accumulator, P_fcOutputting power for the fuel cell.

Dividing the output power interval of the fuel cell into three areas, namely an area A, an area B and an area C from low to high, wherein the area A is a low-efficiency working area of the fuel cell, the area B is a high-efficiency working area of the fuel cell, and the area C is a low-efficiency reducing working area of the fuel cell; the maximum value of the A zone is the lowest power point P of the starting fuel cell_fclowThe maximum value of the B zone is the transition output power P of the BC zone of the fuel cell_fcbcThe maximum value of the C area is the maximum output power P of the fuel cell_fcmax。

When P is present_vehicle<P_fclowIn time, the storage battery outputs power to the vehicle under the state of no over-dischargeSupplying power to the vehicle;

when P is present_fclow<P_vehicle<P_fcmaxWhen the vehicle is running, the fuel cell outputs power to power the vehicle;

when P is present_vehicle>P_fcmaxAnd the output power of the storage battery and the fuel cell jointly supplies power to the vehicle.

Further, a battery charging upper limit SOC is set according to the charging and discharging performance of the battery_maxAnd over-discharge threshold SOC of the battery_minWherein SOC is_min<SOC_max。

When P is present_vehicle<P_fclowWhen the temperature of the water is higher than the set temperature,

if the storage battery SOC<SOC_minFirst, greater than P_fclowIs less than or equal to P_fcbcThe power of the fuel cell is started to meet the power demand of the vehicle, and the redundant energy charges the storage battery to reach the SOC_max；

If the storage battery SOC>SOC_minAnd only the output power of the storage battery is used for supplying power to the vehicle.

Further, when P is_fclow<P_vehicle≤P_fcbcIf the SOC of the storage battery<SOC_minFirst, greater than P_fcbcThe power starting fuel cell meets the vehicle power supply requirement, and the storage battery is charged to SOC in a redundant manner_max。

Further, when P is_fcbc<P_vehicle≤P_fcmaxWhen the battery is in SOC<SOC_minAt a constant P_fcmaxThe power of the fuel cell is started to meet the power supply requirement of the vehicle, and the storage battery is charged to the SOC to reach the SOC_max。

Further, when P is_fcmax≤P_vehicleAnd in time, only the fuel cell is started to discharge, so that the power supply requirement of the vehicle is met.

Further, the storage battery is also provided with a charging working condition value SOC_InWherein, SOC_min≤SOC_In≤SOC_max(ii) a Fuel cell sets its maximum efficiency point power P_fceffmaxWherein P is_fclow<P_fceffmax<P_fcbc。

When P is present_vehicle<P_fclowWhen the temperature of the water is higher than the set temperature,

if the storage battery SOC<SOC_minThe fuel cell is first charged with P_fcbcThe fuel cell is started to meet the power demand of the vehicle, and the redundant energy charges the storage battery to the SOC_InThen switch to P_fceffmaxContinuously charging the storage battery to the SOC_max。

If the storage battery SOC>SOC_minAnd only the output power of the storage battery is used for supplying power to the vehicle.

Further, the storage battery is also provided with a charging working condition value SOC_InWherein, SOC_min≤SOC_In≤SOC_max；

When P is present_fclow<P_vehicle≤P_fcbcIf the SOC of the storage battery<SOC_minThe fuel cell is first charged with P_fcmaxStarting the fuel cell to meet the vehicle power demand and charging the battery to SOC_InThen switch to P_fcbcContinuously charging the storage battery to the SOC_max。

Further, when P is_vehicle<At 0, only the battery is started and charged.

The beneficial technical effects of the invention are as follows:

(1) the method divides the power interval of the fuel cell into three areas, namely a low-efficiency working area of the fuel cell, a high-efficiency working area of the fuel cell and a low-efficiency working area of the fuel cell, and improves the energy utilization efficiency of the whole power system.

(2) The method sets the upper and lower charge-discharge limits according to the charge-discharge internal resistance and the service life requirement of the storage battery, thereby not only preventing the deep charge-discharge of the storage battery and improving the service life and the service stability of the storage battery, but also further improving the energy utilization efficiency.

(3) In the method, if the SOC of the storage battery reaches the lowest limit value, if P_vehicle<P_fclowWhen the fuel cell is started, the fuel cell firstly uses the point P with the second highest efficiency_fcbcThe fuel cell is started to meet the power demand of the vehicle, and the redundant energy charges the storage battery to the SOC_InThen switched to the high efficiency point P_fceffmaxContinuously charging the storage battery to the SOC_max(ii) a If P_fclow<P_vehicle≤P_fcbcThe fuel cell is firstly at the sub-high efficiency point P_fcmaxStarting the fuel cell to meet the vehicle power demand and charging the battery to SOC_InThen switched to the high efficiency point P_fcbcContinuously charging the storage battery to the SOC_max. The fuel cell has less charging power to the storage battery, thereby reducing the secondary conversion of chemical energy and electric energy and improving the economy; simultaneously solves the problem that the storage battery is lower than the SOC for a long time_minAnd stage, the power system cannot meet the requirement of the whole vehicle.

Drawings

FIG. 1 is a schematic diagram of a vehicle fuel cell power control system;

FIG. 2 is a schematic diagram of a fuel cell operating characteristic curve;

FIG. 3 is a logic diagram of a method for distributing energy to a vehicle fuel cell;

FIG. 4 is a schematic sectional view of the operating states of the fuel cell and the battery;

FIG. 5 is a schematic diagram of battery charging and discharging and common working area;

the system comprises a hydrogen storage tank 1, a fuel cell 2, a power assembly controller 3, a storage battery 4, a motor controller 5, a motor 6, a driving shaft 7, a zone 8-A, a zone 9-B, a zone 10-C, a zone 11-I, a zone 12-II, a zone 13-III, a zone 14-IV, a zone 15-V, a zone 16-VI, a zone 17-VII, a zone 18-VII and a common working zone of the storage battery 19.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1 to 5, the fuel cell energy control system for a vehicle includes a hydrogen storage tank 1, a fuel cell 2, a powertrain controller 3, a battery 4, a motor controller 5, an electric motor 6, and a drive shaft 7. The vehicle is powered by the battery 4 and the fuel cell 2 together.

The hydrogen storage tank 1 provides hydrogen for the fuel cell 2, the fuel cell 2 is electrically connected with the power assembly controller 3, the storage battery 4 is electrically connected with the power assembly controller 3, the power assembly controller 3 is electrically connected with the motor controller 5, the motor controller 5 is electrically connected with the motor 6, and the motor is mechanically connected with the driving shaft 7.

The fuel cell 2 generates electricity, the generated electric energy is transmitted to the motor 6 through the power assembly controller 3 and the motor controller 5, and the motor 6 converts the electric energy into mechanical energy for the driving shaft 7 to drive the whole vehicle to run. The battery 4 is an energy storage device between the fuel cell 2 and the motor 6, and plays a role of power balance. The energy distribution between the fuel cell 2 and the battery 4 is realized by the drive train controller 3.

As shown in fig. 2, the operating characteristic curve of the fuel cell divides the power interval of the fuel cell into A, B, C three regions, where a region 8 is an operating inefficiency region of the fuel cell, where the fuel cell is unstable and has very low efficiency; the B area 9 is a high-efficiency working area of the fuel cell, and the working efficiency of the fuel cell in the area is high and reaches 60 percent; zone C10 is a sub-efficient reduced operating zone of the fuel cell, where the fuel cell output is high, but the efficiency is lower than the most efficient zone, at an intermediate level; the maximum power point of the A region is the lowest power point P of the starting fuel cell_fclowThe maximum power point of the B area is the connection point P of the B area and the C area of the fuel cell_fcbcThe maximum power point of the C region is the maximum output power P of the fuel cell_fcmax(ii) a The fuel cell has a maximum efficiency point in zone B, typically about 60% maximum efficiency, and the maximum efficiency point has a power P_fceffmaxSatisfy P_fclow<P_fceffmax<P_fcbc。

As shown in fig. 5, in order to reduce the charge/discharge loss of the battery 4 and improve the energy conversion efficiency, the battery frequent use operating region 19 should be in a region where the charge/discharge internal resistance is reduced and the amount of electricity should be kept in the intermediate SOC range, so that the battery life can be effectively extended. Therefore, in order to effectively prevent the overcharge of the battery 4, the battery charging upper limit SOC is set_maxIn order to effectively prevent over-discharge of the battery 4, a battery over-discharge threshold value SOC is set_min. In order to avoid the battery 4 being in a low SOC state for a long time_minAnd stage, the power system cannot meet the requirement of the whole vehicle. Increase the SOC value of the charging condition_InSatisfies SOC_min≤SOC_In≤SOC_max. General setup SOC_maxIs 0.8，SOC_minIs 0.3, SOC_InIs 0.5.

As shown in fig. 3, the energy distribution method of the fuel cell for the vehicle specifically includes:

detecting an accelerator pedal signal, a brake pedal signal and a storage battery SOC value;

when P is present_vehicle<When 0, only starting the storage battery and charging the storage battery;

when P is present_vehicle<P_fclowWhen the vehicle is not in an over-discharge state, the storage battery outputs power to supply power to the vehicle; if the storage battery SOC>SOC_minOnly the output power of the storage battery meets the requirement of vehicle power supply; if the storage battery SOC<SOC_minThe fuel cell is first charged with P_fcbcThe fuel cell is started to meet the power demand of the vehicle, and the redundant energy charges the storage battery to the SOC_InThen switch to P_fceffmaxContinuously charging the storage battery to the SOC_max。

When P is present_fclow<P_vehicle≤P_fcbcIf the SOC of the storage battery<SOC_minThe fuel cell is first provided with P_fcmaxStarting the fuel cell to meet the vehicle power demand and charging the battery to SOC_InThen switch to P_fcbcContinuously charging the storage battery to the SOC_max. If the storage battery SOC>SOC_minAnd the B area starts the fuel cell, and only the output power of the fuel cell meets the requirement of vehicle power supply.

When P is present_fcbc<P_vehicle≤P_fcmaxWhen the battery is in SOC<SOC_minAt a constant P_fcmaxThe power of the fuel cell is started to meet the power supply requirement of the vehicle, and the storage battery is charged to the SOC to reach the SOC_max(ii) a If the storage battery SOC>SOC_minAnd the C area starts the fuel cell, and only the output power of the fuel cell meets the requirement of vehicle power supply.

When P is present_vehicle>P_fcmaxAnd the output power of the storage battery and the fuel cell jointly supplies power to the vehicle. If the storage battery SOC<SOC_min，P_fcmaxStarting the fuel cell; if the SOC of the storage battery is more than or equal to the SOC_min，P_fcmaxAnd starting the fuel cell, and supplementing part of the storage battery.

In conjunction with the above-described method for distributing energy to fuel cells for vehicles, the operating states of the fuel cells and the storage battery are divided into 8 regions, as shown in fig. 4.

The first zone 11 is used for closing the fuel cell 2, only starting the storage battery 4 and charging the storage battery 4;

in the II area 12, the fuel cell 2 is closed, and only the storage battery 4 is started to discharge, so that the power requirement of the vehicle is met;

in the III area 13, the storage battery 4 is closed, and only the fuel cell 2 is started to discharge, so that the power requirement of the vehicle is met;

in the IV area 14, the fuel cell 2 is started to discharge at the maximum power, and the part with insufficient power is discharged by the storage battery 4 to provide energy so as to meet the power requirement of the vehicle;

zone V15, shutdown of battery 4, first with P_fcbcThe fuel cell 2 is started to meet the demand, and the storage battery 4 is charged unnecessarily until the SOC reaches the SOC_InThen with P_fceffmaxStarting the fuel cell 2 to charge the battery 4 to the SOC to the SOCmax; VI region 16, the battery is turned off, first with P_fcmaxThe fuel cell 2 is started to meet the demand, and the storage battery 4 is charged unnecessarily until the SOC reaches the SOC_InThen with P_fcbcStarting the fuel cell 2 to charge the battery 4 to the SOC to the SOCmax;

VII region 17, shutdown of the battery, with P_fcmaxThe fuel cell 2 is started to meet the demand, and the storage battery 4 is charged unnecessarily until the SOC reaches the SOC_max；

And in the VIII zone 18, the storage battery 4 is closed, and only the fuel cell 2 is started to discharge electricity, so that the power requirement of the vehicle is met.

While a specific example is given above, it will be appreciated by those skilled in the art that: other control schemes can still be converted by modifying the technical scheme provided by the embodiment or replacing part of technical features of the technical scheme; the modifications and the substitutions of the system scheme of the invention do not make the essence of the corresponding technical scheme depart from the spirit and the scope of the technical scheme of the embodiments of the invention.