Recycled energy distribution method and system of vehicle and forklift

Abstract

A method and system for distributing recovered energy of a vehicle and a forklift are applied to the vehicle with an auxiliary power battery and an energy recovery function, and the method comprises the following steps that at least the auxiliary power battery, a cooling system of the vehicle or a fuel cell, a resistor or a super capacitor serve as the flow direction of the recovered energy of the vehicle; monitoring electric quantity information of the auxiliary power battery and recycled energy of the vehicle; according to the electric quantity information, the information of the heat dissipation system and the recycled energy, whether the recycled energy is started to charge the auxiliary power battery or not is judged, and / or whether the recycled energy is started to supply power to the heat dissipation system of the vehicle or the fuel cell or not is judged; or whether the recycled energy is started to flow into the resistor or the super capacitor is determined. Recycled energy of the vehicle is reasonably distributed, the utilization rate of the recycled energy is increased, and energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the field of industrial vehicles, and particularly to a method and system for allocating recovered energy of a vehicle and a forklift truck. Background Art

[0002] Fuel cell vehicles are increasingly favored by the automotive industry because they are cleaner and pollution-free compared to fuel vehicles and have lower operating costs. Usually, there are auxiliary power sources such as lithium batteries inside the fuel cell system. When the vehicle decelerates or brakes, energy is recovered to the lithium battery; when the state of charge (SOC) of the lithium battery is relatively high, in order to avoid overcharging of the lithium battery, energy recovery is usually cancelled, which will cause a sudden change in the vehicle deceleration, is not conducive to reducing energy consumption, and there are safety hazards. Summary of the Invention

[0003] The main object of the present invention is to overcome the above-mentioned defects existing in energy recovery in the prior art, and to provide a method and system for allocating recovered energy of a vehicle and a forklift truck, which reasonably allocate the recovered energy of the vehicle, increase the utilization rate of the recovered energy, and reduce energy consumption.

[0004] The present invention adopts the following technical solutions:

[0005] A method for allocating recovered energy of a vehicle, which is applied to a vehicle with an auxiliary power battery and an energy recovery function, is characterized by including the following:

[0006] At least the auxiliary power battery, the heat dissipation system of the vehicle or the fuel cell, a resistor or a super capacitor is used as the flow direction of the recovered energy of the vehicle;

[0007] Monitor the power information of the auxiliary power battery and the recovered energy of the vehicle;

[0008] Judge whether to turn on the recovered energy to charge the auxiliary power battery, and / or whether to turn on the recovered energy to supply power to the heat dissipation system of the vehicle or the fuel cell, or whether to turn on the recovered energy to flow into the resistor or the super capacitor according to the power information, the information of the heat dissipation system and the recovered energy.

[0009] Compare the power information with a set power threshold. If the power information is less than or equal to the power threshold, turn on the recovered energy to charge the auxiliary power battery; if the power information is greater than the power threshold, then compare the magnitude of the recovered energy with a set energy threshold to judge whether to use the recovered energy to supply power to the heat dissipation system and / or whether to turn on the recovered energy to flow into the resistor or the super capacitor.

[0010] When the power information is less than or equal to the power threshold, the charging of the auxiliary power battery with the recovered energy is enabled, and the inflow of the recovered energy into the resistor or the supercapacitor is turned off, and it is determined whether to supply power to the heat dissipation system of the vehicle or the fuel cell with the recovered energy according to the temperature of the vehicle.

[0011] If the power information is greater than the power threshold, the charging of the auxiliary power battery with the recovered energy is turned off, and the magnitude of the recovered energy is compared with a set energy threshold to determine whether to use the recovered energy to supply power to the heat dissipation system and / or whether to turn on the inflow of the recovered energy into the resistor or the supercapacitor. Specifically:

[0012] If the magnitude of the recovered energy is less than the set energy threshold, the supply of the recovered energy to the heat dissipation system is turned on, and the inflow of the recovered energy into the resistor or the supercapacitor is turned off;

[0013] If the magnitude of the recovered energy is greater than or equal to the set energy threshold, the inflow of the recovered energy into the resistor or the super circuit is turned on, and the supply of the recovered energy to the heat dissipation system is turned off.

[0014] The magnitude of the recovered energy is the power magnitude or the current magnitude of the recovered energy, and the energy threshold is related to the power magnitude or the current magnitude of the heat dissipation system.

[0015] A recovered energy distribution system for a vehicle, characterized by comprising:

[0016] An energy recovery module for realizing the energy recovery of the vehicle;

[0017] A monitoring module for acquiring and monitoring the power information of the auxiliary power battery of the vehicle and the recovered energy of the vehicle;

[0018] A switching module for executing turning on or off the charging of the auxiliary power battery with the recovered energy, turning on or off the supply of the recovered energy to the heat dissipation system of the vehicle or the fuel cell, and turning on or off the inflow of the recovered energy into the resistor or the supercapacitor.

[0019] A comparison and judgment module for determining whether to turn on the charging of the auxiliary power battery with the recovered energy, and / or whether to turn on the supply of the recovered energy to the heat dissipation system of the vehicle or the fuel cell, or whether to turn on the inflow of the recovered energy into the resistor or the supercapacitor according to the power information, the information of the heat dissipation system, and the recovered energy;

[0020] The switching module includes a first switching switch, a second switching switch, and a third switching switch. The first switching switch is connected between the auxiliary power battery and the energy recovery module. The second switching switch is connected between the heat dissipation system and the energy recovery module. The third switch is connected between the resistor or the super capacitor and the energy recovery module.

[0021] The first switching switch is a MOS transistor, a field effect transistor, or a relay. The second switching switch is a MOS transistor, a field effect transistor, or a relay. The third switching switch is a MOS transistor, a field effect transistor, or a relay.

[0022] It further includes a voltage conversion module, which is connected between the heat dissipation system and the energy recovery module to convert the recovered energy and supply power to the heat dissipation system.

[0023] A fuel cell forklift includes a forklift body, and is characterized in that it further includes the recovered energy distribution system of a vehicle as described above.

[0024] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. In the present invention, the auxiliary power battery, the heat dissipation system of the vehicle or the fuel cell, and the resistor or the super capacitor are used as the flow direction of the recovered energy of the vehicle. According to the power information, the information of the heat dissipation system, and the recovered energy, it is judged whether to turn on the recovered energy to charge the auxiliary power battery, and / or whether to turn on the recovered energy to supply power to the heat dissipation system of the vehicle or the fuel cell, or whether to turn on the recovered energy to flow into the resistor or the super capacitor, etc., so as to increase the utilization rate of the recovered energy and reduce energy consumption.

[0026] 2. In the present invention, when the power information is less than or equal to the power threshold, the recovered energy is turned on to charge the auxiliary power battery. If the power information is greater than the power threshold, the magnitude of the recovered energy is compared with the set energy threshold to judge whether to use the recovered energy to supply power to the heat dissipation system and / or whether to turn on the recovered energy to flow into the resistor or the super capacitor, so as to avoid potential safety hazards caused by sudden changes in vehicle deceleration.

[0027] 3. In the present invention, by using the heat dissipation system to realize the utilization of the recovered energy, excessive recovered energy is consumed by the resistor, or the recovered energy is stored by the super capacitor. Compared with simply using the resistor, it is more energy-saving, especially for large-tonnage vehicles, and the energy utilization rate is more obvious.

[0028] 4. In the present invention, the switching module uses the first switching switch, the second switching switch, and the third switching switch to implement the switching on or off of the energy recovery flow path, and MOS transistors, IGBTs, or relays can be used. The resistors and supercapacitors can be appropriate resistors or supercapacitors in the vehicle-related circuits, or additional resistors and supercapacitors can be used, with low cost and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the path distribution of the recovered energy of the present invention;

[0030] Figure 2 is the main flowchart of the method of the present invention;

[0031] Figure 3 is the composition diagram of the system of the present invention;

[0032] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The present invention will be further described below through specific embodiments.

[0034] In the present invention, for terms such as "first", "second", "third", etc., they are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. In the description, the orientation or positional relationship indicated by "upper", "lower", "left", "right", "front", and "rear" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection scope of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0035] In addition, in the description of the present application, unless otherwise specified, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0036] A method for distributing recovered energy of a vehicle is applied to a vehicle with an auxiliary power battery and an energy recovery function, such as a hydrogen fuel cell forklift. The auxiliary power battery means that the battery is used as an auxiliary power source, such as a lithium battery. Having an energy recovery function means that the braking system or working system of the vehicle can convert the kinetic energy generated during the vehicle's driving or working process into electrical energy. For example, it includes the vehicle's starting, accelerating, braking, and decelerating, as well as the lifting and lowering of the forklift forks.

[0037] See Figure 1 , in addition to having an auxiliary power battery and an energy recovery function, a hydrogen fuel cell forklift is also provided with a vehicle controller, a fuel cell system, a cooling system, a working system, etc. The fuel cell system may include a fuel cell controller, a fuel cell, a hydrogen supply module, an air supply module, a DCDC module, etc. The cooling system is used to dissipate heat from the vehicle to prevent the fuel cell from being affected in terms of lifespan and working stability due to excessive or too low vehicle temperature. The working system may include a travel motor controller, a lift motor controller, a travel motor, a lift motor, etc. The vehicle controller is used to control the fuel cell system, the cooling system, the working system, etc., to ensure the coordinated operation of each system.

[0038] The energy recovery distribution method of the present invention includes the following:

[0039] At least the auxiliary power battery, the cooling system of the vehicle or the fuel cell, a resistor or a super capacitor are used as the flow directions of the recovered energy of the vehicle. Monitor the power information of the auxiliary power battery and the recovered energy of the vehicle; judge whether to turn on the recovered energy to charge the auxiliary power battery, and / or whether to turn on the recovered energy to supply power to the cooling system of the vehicle or the fuel cell, or whether to turn on the recovered energy to flow into the resistor or the super capacitor according to the power information, the information of the cooling system and the recovered energy.

[0040] Among them, the power information may be the state of charge of the auxiliary power battery, that is, the available state of the remaining power in the auxiliary power battery. The resistor or the super capacitor may be a suitable resistor or super capacitor in the relevant circuit of the vehicle, or a dedicated resistor or super capacitor additionally added. The resistor can be used to consume the recovered energy, while the super capacitor is used to store the recovered energy. The super capacitor can also be connected to the working system or the braking system of the vehicle, etc., and supply electrical energy for the movement or work of the vehicle by discharging. In practical applications, the number of resistors and super capacitors is at least one, and can be set according to actual needs.

[0041] Further, see Figure 2 , compare the power information with a set power threshold. If the power information is less than or equal to the power threshold, turn on the recovered energy to charge the auxiliary power battery; if the power information is greater than the power threshold, then compare the magnitude of the recovered energy with a set energy threshold to judge whether to use the recovered energy to supply power to the cooling system and / or whether to turn on the recovered energy to flow into the resistor or the super capacitor.

[0042] Among them, the power threshold value ranges from 95% to 98%, but is not limited thereto, and can be set according to actual requirements. In the present invention, it is set that when the power information is less than or equal to the power threshold value, the recovered energy is turned on to charge the auxiliary power battery, and the recovered energy flowing into the resistor or supercapacitor is turned off. When charging the auxiliary power battery is turned on, when the vehicle is in the state of recovering energy, the recovered energy charges the auxiliary power battery, and the fuel cell also charges the auxiliary power battery, but the recovered energy does not flow into the resistor or supercapacitor to avoid the reduction of the recovered energy.

[0043] To ensure the normal operation of the vehicle, when the power information is less than or equal to the power threshold value, it is also judged whether to turn on the recovered energy to supply power to the heat dissipation system according to the heat dissipation requirement of the vehicle, and the heat dissipation requirement can be judged according to the temperature of the vehicle. The temperature of the vehicle is compared with the set temperature threshold value for judgment, and the temperature threshold value range can be set at about 60°C. When the vehicle temperature is within the temperature threshold value range, there is no need to turn on the recovered energy to supply power to the heat dissipation system, and when the vehicle temperature is outside the temperature threshold value range, the recovered energy is turned on to supply power to the heat dissipation system.

[0044] If the power information is greater than the power threshold value, it means that the remaining power of the auxiliary power battery is sufficient and there is no need to charge, so the charging of the auxiliary power battery by the recovered energy is turned off to avoid overcharging of the battery caused by the recovered energy charging the auxiliary power battery; and the magnitude of the recovered energy is compared with the set energy threshold value to judge whether to use the recovered energy to supply power to the heat dissipation system and / or whether to turn on the recovered energy to flow into the resistor or supercapacitor.

[0045] Among them, the magnitude of the recovered energy is the power magnitude or current magnitude of the recovered energy, and the energy threshold value corresponds to the power magnitude or current magnitude of the heat dissipation system. That is, when the magnitude of the recovered energy is the actual recovered power, the energy threshold value is related to the power of the heat dissipation system, and when the magnitude of the recovered energy is the current, the energy threshold value is related to the current of the heat dissipation system.

[0046] Furthermore, comparing the magnitude of the recovered energy with the set energy threshold value to judge whether to use the recovered energy to supply power to the heat dissipation system and / or whether to turn on the recovered energy to flow into the resistor or supercapacitor specifically includes the following:

[0047] If the magnitude of the recovered energy is less than the set energy threshold value, the recovered energy is turned on to supply power to the heat dissipation system for the utilization of the recovered energy, and the recovered energy flowing into the resistor or supercapacitor is turned off. If the magnitude of the recovered energy is greater than or equal to the set energy threshold value, that is, the recovered energy exceeds the energy required by the heat dissipation system, the recovered energy flowing into the resistor or super circuit is turned on, and the power supply of the recovered energy to the heat dissipation system is turned off or on.

[0048] Based on this, see Figure 3 , the present invention also proposes a recovered energy distribution system for a vehicle, including:

[0049] An energy recovery module for implementing energy recovery of a vehicle.

[0050] A monitoring module for obtaining and monitoring the power information of the auxiliary power battery of the vehicle and the recovered energy of the vehicle.

[0051] A switching module for executing charging of the auxiliary power battery by turning on or off the recovered energy, powering the heat dissipation system of the vehicle or fuel cell by turning on or off the recovered energy, and turning on or off the flow of the recovered energy into a resistor or supercapacitor.

[0052] A comparison and judgment module for judging whether to charge the auxiliary power battery by turning on the recovered energy, and / or whether to power the heat dissipation system of the vehicle or fuel cell by turning on the recovered energy, or whether to turn on the flow of the recovered energy into a resistor or supercapacitor according to the power information, the information of the heat dissipation system and the recovered energy.

[0053] The switching module includes a first switching switch S1, a second switching switch S2 and a third switching switch S3. The first switching switch S1 is connected between the auxiliary power battery and the energy recovery module. The second switching switch S2 is connected between the heat dissipation system and the energy recovery module. The third switch is connected between the resistor or supercapacitor and the energy recovery module.

[0054] The energy recovery module, the monitoring module, the switching module and the comparison and judgment module of the system of the present invention cooperate to execute the above-mentioned recovered energy distribution method for a vehicle.

[0055] Wherein, the first switching switch S1 is a MOS transistor or a field effect transistor or a relay. When the first switching switch S1 is turned off, the charging of the auxiliary power battery by the recovered energy is turned off. When the first switch is turned on, the charging of the auxiliary power battery by the recovered energy is turned on. The second switching switch S2 is a MOS transistor or a field effect transistor or a relay. When the second switching switch S2 is turned off, the power supply to the heat dissipation system by the recovered energy is turned off. When the first switch is turned on, the power supply to the heat dissipation system by the recovered energy is turned on. The third switching switch S3 is a MOS transistor or a field effect transistor or a relay. When the third switching switch S3 is turned off, the flow of the recovered energy into the resistor or supercapacitor is turned off. When the third switch is turned on, the flow of the recovered energy into the resistor or supercapacitor is turned on.

[0056] Further, in order to ensure that the recovered energy can supply power to the heat dissipation system normally, a voltage conversion module is further included. The voltage conversion module is connected between the heat dissipation system and the energy recovery module to convert the recovered energy and convert it into a suitable supply voltage to supply power to the heat dissipation system.

[0057] Based on this, the present invention also provides a fuel cell forklift, which includes a forklift body. The forklift body includes the auxiliary power battery, vehicle controller, fuel cell system, cooling system, working system, etc. described above, and also includes the energy recovery distribution system for a vehicle as described above.

[0058] Application Example

[0059] Suppose a 6 - 8T hydrogen fuel cell forklift, according to the vehicle requirements, the power of the fuel cell it is equipped with is about 35kW, the lithium battery is about 20kWh (80V 250Ah), and the power of the cooling system matched by the vehicle is 3 - 5kW. Set the power threshold B1 = 95% - 98%. Combining with the table, the energy recovery is distributed as follows:

[0060]

[0061] When the power information of the auxiliary power battery ≤ B1, when the driver releases the accelerator or lightly steps on the brake, the vehicle will generate energy recovery, close the first switching switch S1, disconnect the second switching switch S2 and the third switching switch S3, and the recovered energy is used to charge the lithium battery.

[0062] When the power information of the auxiliary power battery > B1, and the driver releases the accelerator or lightly steps on the brake, the vehicle will generate energy recovery. If the recovery power of the recovered energy at this time ≤ 5kW (or the recovery current ≤ 62.5A), then disconnect the first switching switch S1, close the second switching switch S2, and disconnect the third switching switch S3, and the recovered energy is supplied to the cooling system through the voltage conversion module.

[0063] When the recovery power of the recovered energy > 5kW (or the recovery current > 62.5A), then disconnect the first switching switch S1 and the second switching switch S2, close the third switching switch S3, and consume the recovered energy through a resistor, or store the energy through a supercapacitor. In this case, since the resistance in the loop where the second switching switch S2 is located is less than the resistance in the loop where the third switching switch S3 is located, the second switching switch S2 can also be in the closed state, mainly consuming the recovered energy through a resistor, or storing the energy through a supercapacitor.

[0064] In the present invention, the resistor is selected according to the maximum recovery power. Suppose the maximum recovery power is 10kw, and after deducting 5kW of the cooling system, a 5kw - specification resistor can be selected.

[0065] The supercapacitor is selected to meet at least the maximum energy recovery value that can be stored once. Suppose the maximum energy recovery power is 5kW and the longest duration is 30s, then the maximum recovered energy value is E = 0.041kWh = 147600J (Joule). According to the energy storage formula of the supercapacitor E = 0.5C(U 1 2 -U2 2 ), where E represents the energy storage value of the supercapacitor, C represents the capacitance value of the supercapacitor, and U 1 , U 2 is the voltage change of the capacitor during energy recovery. Common supercapacitor specifications are 48V 165F. At the same time, the selection of the supercapacitor also needs to synchronously consider the operable voltage range of the electric control system. For example, based on the 80V voltage platform of this embodiment, the selectable working voltage range is about 50 - 80V. Therefore, a scheme of connecting two supercapacitors in series can be selected to achieve the corresponding voltage range. The recoverable capacity it can store is 0.5*(165 / 2)*(80*80 - 50*50) = 160875J (joules) > 147600J (joules), which can meet the requirements of energy recovery.

[0066] The above is only the specific implementation manner of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantive modification made to the present invention using this concept shall fall within the scope of infringement of the protection scope of the present invention.

Claims

1. A method for distributing recovered energy of a vehicle, applied to a vehicle with an auxiliary power battery and an energy recovery function, characterized in that: These include: At least the auxiliary power battery, the cooling system of the vehicle or the fuel cell, the resistor or the supercapacitor are used as the flow direction of the recovered energy of the vehicle; Monitoring the power information of the auxiliary power battery and the recovered energy of the vehicle; According to the power information, the information of the cooling system and the recovered energy, it is determined whether to turn on the recovered energy to charge the auxiliary power battery, and / or whether to turn on the recovered energy to power the cooling system of the vehicle or the fuel cell, or whether to turn on the recovered energy to flow into the resistor or the supercapacitor.

2. A method for distributing recovered energy of a vehicle according to claim 1, characterized in that: The power information is compared with a set power threshold. If the power information is less than or equal to the power threshold, the recovery energy is turned on to charge the auxiliary power battery. If the power information is greater than the power threshold, the size of the recovery energy is compared with the set energy threshold to determine whether the recovery energy is used to power the cooling system and / or whether the recovery energy is turned on to flow into the resistor or the supercapacitor.

3. A method for distributing recovered energy of a vehicle as claimed in claim 2, characterized in that: If the power information is less than or equal to the power threshold, the recovery energy is turned on to charge the auxiliary power battery, and the recovery energy is turned off to flow into the resistor or the supercapacitor, and it is determined whether to turn on the recovery energy to power the cooling system of the vehicle or the fuel cell based on the temperature of the vehicle.

4. A method for distributing recovered energy of a vehicle as claimed in claim 2, characterized in that: If the power information is greater than the power threshold, the charging of the auxiliary power battery by the recovered energy is turned off, and the size of the recovered energy is compared with the set energy threshold to determine whether the recovered energy is used to power the cooling system and / or whether the recovered energy is turned on to flow into the resistor or the supercapacitor, specifically: If the size of the recovered energy is less than the set energy threshold, the recovered energy is turned on to supply power to the heat dissipation system, and the recovered energy is turned off to flow into the resistor or the supercapacitor; If the size of the recovered energy is greater than or equal to the set energy threshold, the recovered energy is turned on to flow into the resistor or the super circuit, and the recovered energy is turned off to supply power to the heat dissipation system.

5. A method for distributing recovered energy of a vehicle as claimed in claim 4, characterized in that: The magnitude of the recovered energy is the power magnitude or current magnitude of the recovered energy, and the energy threshold is correspondingly related to the power magnitude or current magnitude of the heat dissipation system.

6. A vehicle recovery energy distribution system, characterized in that: include: An energy recovery module, used to realize energy recovery of the vehicle; A monitoring module, which obtains and monitors the power information of the vehicle's auxiliary power battery and the vehicle's recovered energy; The switching module is used to turn on or off the recovery energy to charge the auxiliary power battery, turn on or off the recovery energy to power the cooling system of the vehicle or the fuel cell, and turn on or off the recovery energy to flow into the resistor or the supercapacitor. A comparison and judgment module determines, according to the power information, the information of the cooling system and the recovered energy, whether to turn on the recovered energy to charge the auxiliary power battery, and / or whether to turn on the recovered energy to power the cooling system of the vehicle or the fuel cell, or whether to turn on the recovered energy to flow into the resistor or the supercapacitor.

7. A vehicle recovery energy distribution system as claimed in claim 6, characterized in that: The switching module includes a first switching switch, a second switching switch and a third switching switch. The first switching switch is connected between the auxiliary power battery and the energy recovery module, the second switching switch is connected between the heat dissipation system and the energy recovery module; and the third switch is connected between the resistor or the supercapacitor and the energy recovery module.

8. A vehicle recovery energy distribution system as claimed in claim 7, characterized in that: The first switch adopts a MOS tube or a field effect tube or a relay; the second switch adopts a MOS tube or a field effect tube or a relay; the third switch adopts a MOS tube or a field effect tube or a relay.

9. A vehicle recovery energy distribution system as claimed in claim 6, characterized in that: A voltage conversion module is also included, and the voltage conversion module is connected between the heat dissipation system and the energy recovery module to convert the recovered energy to power the heat dissipation system.

10. A fuel cell forklift, comprising a forklift body, characterized in that: It also includes a vehicle recovery energy distribution system according to any one of claims 6 to 9.

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