CN110341504B - An extended-range electric vehicle power system and its control method - Google Patents

Abstract

The invention relates to a range-extending type electric vehicle power system and a control method thereof, belonging to the technical field of electric vehicle power systems; the technical problems to be solved are as follows: an improvement of a power system structure and a control method of a range-extending electric vehicle are provided; the technical scheme adopted for solving the technical problems is as follows: comprising the following steps: the system comprises a fuel cell module, a power cell module, a hydrogen storage and supply module and a power system control module; the fuel cell system comprises a fuel cell module, a fuel cell air supply unit, a hydrogen storage and supply module and a fuel cell control management module, wherein the fuel cell module is internally provided with a fuel cell stack and the fuel cell control management module; the hydrogen storage and supply module is internally provided with a hydrogen storage tank body, an air outlet port of the hydrogen storage tank body is connected with the fuel cell stack after being sequentially connected with a pressure reducing valve, a three-way valve and a stop valve in series through a gas pipeline, and a branch port of the three-way valve is also connected with a hydrogen outlet end of the fuel cell stack after being connected with a hydrogen circulating pump in series; the invention is applied to the power system of the electric vehicle.

Description

An extended-range electric vehicle power system and its control method

Technical field

The present invention is an extended-range electric vehicle power system and a control method thereof, which belongs to the technical field of electric vehicle power systems.

Background technique

In recent years, due to energy security issues such as the world oil crisis and environmental pollution, the transition of automobile research and development from fuel vehicles to electric vehicles has become a development trend; the lithium-ion batteries currently used in electric vehicles have advantages such as high energy storage density and simple grouping technology. , has become the first choice and popular electric vehicle battery in recent years, but it also has technical problems such as short cruising range, long charging time, high risk of thermal runaway, and high recycling costs, which results in a long replacement cycle of lithium battery technology and affects market promotion. , making the technical advantages of electric vehicles unstable, and electric vehicles still cannot completely replace fuel vehicles in a short period of time.

Hydrogen fuel cells are power generation devices that directly convert chemical energy stored in hydrogen into electrical energy. They have the advantages of wide fuel sources, high energy conversion efficiency, zero emissions, low recycling costs, and modular integration. Hydrogen fuel cell engines have the advantages of energy storage. It has high density (the theoretical power generation of 1kg hydrogen is about 15kWh) and fast energy replenishment (general hydrogenation time for buses and logistics vehicles is about 3 minutes). In recent years, it has become one of the development directions of new energy vehicle power systems.

However, there are still corresponding technical obstacles in the practical application of using hydrogen fuel cells as a power source for automobiles, such as frequent starts and stops during driving and a large operating speed range. However, a single hydrogen fuel cell engine has poor load following performance and is difficult to meet the complex requirements of driving. Working conditions; on the other hand, fuel cell engines are still in the early stages of technological development, and frequent operation under variable load conditions may cause rapid degradation of their performance and greatly reduce their service life.

Contents of the invention

In order to overcome the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide an improvement in the structure and control method of the power system of an extended-range electric vehicle.

In order to solve this technical problem, the technical solution adopted by the present invention is: an extended-range electric vehicle power system, including: a fuel cell module, a power battery module, a hydrogen storage and hydrogen supply module, and a power system control module;

A fuel cell stack and a fuel cell control and management module are provided inside the fuel cell module, and the fuel cell stack is connected to the fuel cell air supply unit and the hydrogen storage and hydrogen supply module through gas pipelines;

The hydrogen storage and hydrogen supply module is equipped with a hydrogen storage tank inside, and the gas outlet port of the hydrogen storage tank is connected in series with a pressure reducing valve, a three-way valve, and a stop valve through a gas pipeline, and is connected to the fuel cell stack. The branch port of the three-way valve is also connected in series with a hydrogen circulation pump and connected to the hydrogen outlet end of the fuel cell stack;

The fuel cell stack is also connected to a back pressure valve;

Both ends of the fuel cell stack are respectively connected to the thermal management module, and the thermal management module is connected to the fuel cell control and management module through wires;

The output end of the fuel cell stack is connected to the DC boost module and then connected in parallel with the power battery module;

The output end of the fuel cell stack is also provided with a diode to limit current flow in one direction;

The signal output ends of the fuel cell control management module and the power battery module are connected to the power system control module;

The signal output end of the fuel cell control management module is also connected to the control end of the fuel cell air supply unit, pressure reducing valve, three-way valve, stop valve, hydrogen circulation pump, and back pressure valve;

The positive output terminal of the fuel cell module is connected in parallel to the positive output terminal of the power battery module and then connected to the positive input terminal of the motor.

The fuel cell air supply unit is provided with a filter, an air compressor, an intercooler, and a humidifier.

The power battery module is equipped with a voltage, current, and temperature acquisition unit, a relay, and a control management unit.

The battery used inside the power battery module is a lithium-ion battery, a nickel-hydrogen battery, a nickel-chromium battery or a lead-acid battery.

An extended-range electric vehicle power system control method, including an electric vehicle power-on method and an electric vehicle power-off method;

The method of powering on the electric vehicle includes the following steps:

While the electric vehicle is driving, the power system control module collects the remaining power data provided by the power battery module in real time:

When the collected remaining power data is greater than the remaining power threshold A set inside the power system control module, the power system control module sends control signals to the fuel cell control management module and power battery module respectively, and controls the power battery module to supply power to the motor alone;

When the collected remaining power data is less than the remaining power threshold A set internally in the power system control module, the power system control module sends control signals to the fuel cell control management module and power battery module respectively, and controls the fuel cell module and power battery module to simultaneously The motor supplies power; at the same time, the excess power generated by the fuel cell module charges the power battery module until the power battery module is fully charged, and then the power system control module controls the fuel cell module to stop supplying external power;

The method of powering off the electric vehicle includes the following steps:

After the electric vehicle is stopped and shut down, the power system control module collects the remaining power data provided by the power battery module in real time:

When the collected remaining power data is less than the remaining power threshold B set internally in the power system control module, the power system control module sends a control signal to the fuel cell control management module to control the fuel cell module to continue to supply power to the outside and charge the power battery module. Until the power battery module is fully charged, the power system control module controls the fuel cell module to stop supplying external power.

Compared with the existing technology, the beneficial effects of the present invention are: the present invention uses fuel cells and power batteries as dual power sources for electric vehicles, effectively overcomes the application shortcomings of hydrogen fuel cells, brings into play the advantages and disadvantages of both, and provides stability for electric vehicles. Reliable power; compared with the existing pure lithium battery electric vehicle power system, it has the advantages of fast energy replenishment, long cruising range and low recycling cost; compared with the existing fuel cell power system, it has good power performance and long operating life , The advantages of high operational reliability.

Description of the drawings

The present invention will be further described below in conjunction with the accompanying drawings:

Figure 1 is a schematic structural diagram of the present invention;

Figure 2 is a flow chart of power-on steps of the present invention;

Figure 3 is a flow chart of power-off steps according to the present invention;

In the picture: 1 is the fuel cell module, 2 is the power battery module, 3 is the hydrogen storage and hydrogen supply module, 4 is the power system control module, 5 is the motor, 6 is the fuel cell stack, 7 is the fuel cell air supply unit, 8 is Pressure reducing valve, 9 is the three-way valve, 10 is the stop valve, 11 is the hydrogen circulation pump, 12 is the back pressure valve, 13 is the thermal management unit, 14 is the fuel cell control management module, 15 is the DC boost module, 16 is diode.

Detailed ways

As shown in Figure 1, an extended-range electric vehicle power system of the present invention includes: a fuel cell module (1), a power battery module (2), a hydrogen storage and hydrogen supply module (3) and a power system control module (4);

The fuel cell module (1) is provided with a fuel cell stack (6) and a fuel cell control and management module (14). The fuel cell stack (6) is connected to the fuel cell air supply unit (7) through a gas pipeline. , connected to the hydrogen storage and supply module (3);

The hydrogen storage and supply module (3) is equipped with a hydrogen storage tank inside, and the gas outlet port of the hydrogen storage tank is connected in series with a pressure reducing valve (8), a three-way valve (9), and a stop valve ( 10), it is connected to the fuel cell stack (6), and the branch port of the three-way valve (9) is also connected in series to the hydrogen circulation pump (11) and then connected to the hydrogen outlet end of the fuel cell stack (6);

The fuel cell stack (6) is also connected to a back pressure valve (12);

Both ends of the fuel cell stack (6) are connected to a thermal management module (13) respectively, and the thermal management module (13) is connected to the fuel cell control and management module (14) through wires;

The output end of the fuel cell stack (6) is connected to the DC boost module (15) and then connected in parallel with the power battery module (2);

The output end of the fuel cell stack (6) is also provided with a diode (16) to limit the flow of current in one direction;

The signal output ends of the fuel cell control management module (14) and the power battery module (2) are connected to the power system control module (4);

The signal output end of the fuel cell control management module (14) is also connected to the fuel cell air supply unit (7), pressure reducing valve (8), three-way valve (9), stop valve (10), and hydrogen circulation pump ( 11), the control end of the back pressure valve (12) is connected;

The positive output terminal of the fuel cell module (1) is connected in parallel to the positive output terminal of the power battery module (2) and then connected to the positive input terminal of the motor (5).

The fuel cell air supply unit (7) is equipped with a filter, an air compressor, an intercooler, and a humidifier inside.

The power battery module (2) is internally provided with a voltage, current, and temperature acquisition unit, a relay, and a control management unit.

The battery used inside the power battery module (2) is a lithium-ion battery, a nickel-hydrogen battery, a nickel-chromium battery or a lead-acid battery.

An extended-range electric vehicle power system control method, including an electric vehicle power-on method and an electric vehicle power-off method;

The method of powering on the electric vehicle includes the following steps:

While the electric vehicle is driving, the power system control module (4) collects the remaining power data provided by the power battery module (2) in real time:

When the collected remaining power data is greater than the remaining power threshold A set internally in the power system control module (4), the power system control module (4) sends controls to the fuel cell control management module (14) and the power battery module (2) respectively. The signal controls the power battery module (2) to supply power to the motor (5) alone;

When the collected remaining power data is less than the remaining power threshold A set internally in the power system control module (4), the power system control module (4) sends controls to the fuel cell control management module (14) and the power battery module (2) respectively. signal to control the fuel cell module (1) and the power battery module (2) to supply power to the motor (5) at the same time; at the same time, the excess power generated by the fuel cell module (1) charges the power battery module (2) until the power battery module (2) 2) When the power is fully charged, the power system control module (4) controls the fuel cell module (1) to stop supplying external power;

The method of powering off the electric vehicle includes the following steps:

After the electric vehicle is stopped and shut down, the power system control module (4) collects the remaining power data provided by the power battery module (2) in real time:

When the collected remaining power data is less than the remaining power threshold B set internally in the power system control module (4), the power system control module (4) sends a control signal to the fuel cell control management module (14) to control the fuel cell module (1 ) continues to supply power to the outside and charge the power battery module (2) until the power battery module (2) is fully charged, and then the power system control module (4) controls the fuel cell module (1) to stop supplying power to the outside.

The invention integrates a power type power battery and an energy storage type hydrogen fuel cell. The two power generation technologies have complementary advantages. The power battery is in a shallow charging and shallow working state, and the fuel cell generates electricity in a stepped and constant current mode. It not only provides good Powerful performance, high battery life and fast energy replenishment.

In view of the fact that deep charging and discharging will accelerate the performance degradation of the power battery, the lithium battery used in the present invention is in a shallow charging and shallow working state, which can avoid the performance degradation of the lithium battery and extend its service life.

In view of the fact that the external power supply of the fuel cell is an electrochemical power generation process, electrochemical balance is particularly important for the stability of its power generation. Therefore, the fuel cell used in the present invention works in a step-by-step constant current mode, which can avoid water damage that may be caused by frequent changes in working conditions. , gas and heat imbalance can improve the power generation stability of the fuel cell and extend its working life.

When the fuel cell module 1 and the power battery module 2 are operating normally, the temperature sensors and battery management control modules installed on the periphery collect relevant data on their working status in real time, and the corresponding data are finally fed back to the power system control module 4 for data analysis. Processing, the power system control module 4 compares the collected data with the preset threshold to determine whether its working status is normal, and sends control signals to the corresponding control valves, pump bodies, and charge and discharge modules according to the judgment results, so that the corresponding battery module always Maintain a stable power supply.

As shown in Figures 2 and 3, the present invention can be applied to starting a car, and the steps are as follows:

After the car is started, the power system control module 4 receives and measures the remaining power value sent by the power battery module 2 in real time, and performs corresponding control according to the following judgment rules:

Scenario 1: If the measured remaining power is higher than the remaining power threshold A (generally, the threshold can be set to 40% of the full power, or adjusted to other values according to the characteristics of the power battery, mainly considering the impact of deep discharge of the power battery on its performance) ), then the power battery module 2 is controlled to drive the motor 5 alone;

Scenario 2: If the measured remaining power is lower than the remaining power threshold A, the fuel cell module 1 is controlled to start automatically, so that the fuel cell module 1 and the power battery module 2 jointly drive the motor 5 and charge the power battery module 2 at the same time. When the battery module 2 reaches a fully charged state, the fuel cell module 1 is controlled to stop output;

After the car is stopped, when the remaining power of the power battery module is lower than the remaining power threshold B (the threshold can be set to 30%-50% of the full power, or a larger range, determined based on the self-discharge characteristics of the power battery to prevent it from being left for a long time performance degradation), the fuel cell module 1 is controlled to start automatically and the power battery module 2 is charged.

In order to improve the stability and reliability of fuel cell power generation, the present invention sets the working mode of the fuel cell module to the constant current output mode so that the fuel cell operates in a relatively stable state; in order to ensure the power performance of the entire vehicle, the present invention sets the The output of the fuel cell is divided into three current gears: high, medium and low, that is, three power gears (the number of gears can also be set according to specific needs); due to the weak overload capacity of the fuel cell, choosing high-end generally corresponds to the fuel For the rated current range of the battery, the medium and low ranges can be set to 80% and 60% of the rated current respectively, or other values can be set according to the characteristics of the fuel cell stack and the specific thresholds of the fuel cell auxiliary system.

According to the remaining power value of the power battery, the fuel cell control management module 14 automatically adjusts the fuel cell output gear according to the present invention. The following is one embodiment of the present invention: For example, during driving of a car, when the remaining power of the fuel cell is lower than the remaining power threshold When A, you can select high-end output; when the remaining power of the fuel cell is between 90% and 95% of full power, select mid-range output; when the remaining power of the fuel cell is higher than 95% of full power, select low-end output.

The fuel cell used in the present invention is a chemical battery, and its power generation process is an electrochemical reaction. During the power generation process, satisfying the balance of water, gas (including hydrogen and oxygen in the air) and heat is the prerequisite for stable power generation of the fuel cell, and adjusting the current gear Changes require the system to establish a new water, gas, and heat balance under the new current value; therefore, when the current gear changes, the fuel cell control management module 14 should promptly adjust the parameter thresholds of the fuel cell, including the flow rates of the hydrogen supply unit and the air supply unit. , pressure, temperature, humidity and temperature of the fuel cell stack, etc.

When the present invention is applied, the fuel cell module 1, the power battery module 2, and the hydrogen storage and hydrogen supply module 3 are packaged in a unified manner, and integrated and installed in the power system of the vehicle to provide power for the drive motor. During the installation process, the corresponding Carry out corresponding layout design of battery module devices, set up corresponding metal brackets, end plates, covers, and trays, connect corresponding gas pipelines to fuel cell module 1 to meet the needs of transporting air oxygen and hydrogen, and install the control and management modules of the two batteries In the corresponding section, electrical connections are made with the corresponding functional modules and monitoring modules through wires, and finally, screws are used to reliably encapsulate the system to complete the installation of the extended-range electric vehicle power system.

The power system provided by the invention can integrate modular structure, power expansion (from tens of watts to hundreds of kilowatts), and energy storage expansion, and can be applied to bicycles and tricycles with low power power and cars and buses with high power power system. , trucks, etc., with wide range of uses and good prospects.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention. scope.

Claims (1)

1. An extended-range electric vehicle power system, characterized by: including: a fuel cell module (1), a power battery module (2), a hydrogen storage and hydrogen supply module (3) and a power system control module (4); The fuel cell module (1) is provided with a fuel cell stack (6) and a fuel cell control and management module (14). The fuel cell stack (6) is connected to the fuel cell air supply unit (7) through a gas pipeline. , connected to the hydrogen storage and supply module (3); The hydrogen storage and supply module (3) is equipped with a hydrogen storage tank inside, and the gas outlet port of the hydrogen storage tank is connected in series with a pressure reducing valve (8), a three-way valve (9), and a stop valve ( 10), it is connected to the fuel cell stack (6), and the branch port of the three-way valve (9) is also connected in series to the hydrogen circulation pump (11) and then connected to the hydrogen outlet end of the fuel cell stack (6); The fuel cell stack (6) is also connected to a back pressure valve (12); Both ends of the fuel cell stack (6) are connected to a thermal management module (13) respectively, and the thermal management module (13) is connected to the fuel cell control and management module (14) through wires; The output end of the fuel cell stack (6) is connected to the DC boost module (15) and then connected in parallel with the power battery module (2); The output end of the fuel cell stack (6) is also provided with a diode (16) to limit the flow of current in one direction; The signal output ends of the fuel cell control management module (14) and the power battery module (2) are connected to the power system control module (4); The signal output end of the fuel cell control management module (14) is also connected to the fuel cell air supply unit (7), pressure reducing valve (8), three-way valve (9), stop valve (10), and hydrogen circulation pump ( 11), the control end of the back pressure valve (12) is connected; The positive output terminal of the fuel cell module (1) is connected in parallel to the positive output terminal of the power battery module (2) and then connected to the positive input terminal of the motor (5); The fuel cell air supply unit (7) is equipped with a filter, an air compressor, an intercooler, and a humidifier; The power battery module (2) is internally provided with a voltage, current, and temperature acquisition unit, a relay, and a control management unit; The battery used inside the power battery module (2) is a lithium-ion battery, a nickel-hydrogen battery, a nickel-chromium battery or a lead-acid battery; The control method of the extended-range electric vehicle power system includes a method of powering on the power of the electric vehicle and a method of powering off the power of the electric vehicle; The method of powering on the electric vehicle includes the following steps: While the electric vehicle is driving, the power system control module (4) collects the remaining power data provided by the power battery module (2) in real time: When the collected remaining power data is greater than the remaining power threshold A set internally in the power system control module (4), the power system control module (4) sends controls to the fuel cell control management module (14) and the power battery module (2) respectively. The signal controls the power battery module (2) to supply power to the motor (5) alone; When the collected remaining power data is less than the remaining power threshold A set internally in the power system control module (4), the power system control module (4) sends controls to the fuel cell control management module (14) and the power battery module (2) respectively. signal to control the fuel cell module (1) and the power battery module (2) to supply power to the motor (5) at the same time; at the same time, the excess power generated by the fuel cell module (1) charges the power battery module (2) until the power battery module (2) 2) When the power is fully charged, the power system control module (4) controls the fuel cell module (1) to stop supplying external power; The method of powering off the electric vehicle includes the following steps: After the electric vehicle is stopped and shut down, the power system control module (4) collects the remaining power data provided by the power battery module (2) in real time: When the collected remaining power data is less than the remaining power threshold B set internally in the power system control module (4), the power system control module (4) sends a control signal to the fuel cell control management module (14) to control the fuel cell module (1 ) continues to supply power to the outside and charge the power battery module (2) until the power battery module (2) is fully charged, and then the power system control module (4) controls the fuel cell module (1) to stop supplying power to the outside.