Heavy electric forklift battery capacity matching method based on working condition requirements

Abstract

The invention is suitable for the technical field of new energy industrial vehicle batteries, and particularly relates to a heavy electric forklift battery electric quantity matching method based on working condition demands, and the method comprises the steps: determining the power demand of a walking system, the power demand of a lifting system, the power demand of a thermal management system and the power demand of a low-voltage system of a heavy electric forklift, calculating the total power demand of the heavy electric forklift; target energy of a battery of the heavy electric forklift is determined; and matching the capacity of the battery basic units, the number of the battery basic units connected in parallel and the voltage of the battery basic units according to the target energy of the battery of the heavy-duty electric forklift, and supplying power to the heavy-duty electric forklift. The electric quantity of the battery is redundant relative to the required power of the forklift, the discharge rate of the battery in the using process is small, and the service life is prolonged; due to the split type arrangement, the batteries can be arranged in the automobile in a scattered mode, the space flexibility is greatly improved, and assembling, disassembling and maintaining are easy.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy industrial vehicle batteries, and particularly relates to a battery power matching method for heavy-duty electric forklifts based on working condition requirements. Background Technique

[0002] With the rapid popularization of new energy technology in the construction machinery field, electric forklifts are gradually developing towards large tonnage and high power. For heavy-duty electric forklifts above 12 tons, the instantaneous power requirements for working conditions such as lifting and traveling can reach more than 300 kW, which poses a severe challenge to the power matching of the power battery system. At present, the integrated battery design scheme commonly used in the industry has exposed many problems in the application scenarios of heavy-duty electric forklifts:

[0003] Firstly, in terms of spatial layout, the large-capacity integrated battery pack is huge in volume, and it is difficult for the forklift chassis structure to provide sufficient independent installation space. Traditional solutions often need to sacrifice the vehicle counterweight design or reduce the space of other functional modules, resulting in poor coordination of the overall vehicle layout. Secondly, in terms of vehicle type adaptation, the existing matching methods require dedicated battery packs to be designed for different tonnage vehicle types respectively. Especially for non-standard customized vehicle types above 12 tons, battery structure reconstruction, re-matching and other development work need to be carried out for each project. This non-standard development mode leads to problems such as long R & D cycle and high cost, seriously restricting the response ability to the customized market. Finally, in terms of system reliability, the integrated battery pack has a risk of single-point failure. Once a failure occurs, the actions of the entire forklift will be restricted and it can only wait for maintenance in place. Seriously affecting the continuity of logistics operations. Summary of the Invention

[0004] The purpose of the present invention is to provide a battery power matching method for heavy-duty electric forklifts based on working condition requirements, aiming to solve the problem that the large-capacity integrated battery pack is huge in volume and it is difficult for the forklift chassis structure to provide sufficient independent installation space. Traditional solutions often need to sacrifice the vehicle counterweight design or reduce the space of other functional modules, resulting in poor coordination of the overall vehicle layout.

[0005] The present invention is implemented as follows. A battery power matching method for heavy-duty electric forklifts based on working condition requirements, the method includes:

[0006] Determine the power requirements of the traveling system, lifting system, thermal management system and low-voltage system of the heavy-duty electric forklift, and calculate the total power requirement of the heavy-duty electric forklift;

[0007] Determine the target energy of the heavy-duty electric forklift battery according to the total power requirement, traveling system power requirement, lifting system power requirement, thermal management system power requirement and low-voltage system power requirement of the heavy-duty electric forklift;

[0008] Power the heavy-duty electric forklift by matching the capacity of the battery basic unit, the number of parallel-connected battery basic units, and the voltage of the battery basic unit according to the target energy of the heavy-duty electric forklift battery.

[0009] Preferably, the battery basic unit includes a vertical bracket, a horizontal bracket, a partition, a lifting ring, a high-voltage and communication line connection port, a first intermediate wire, a high-voltage positive wire, a high-voltage negative wire, a first intermediate coolant pipe, a communication line inlet, a communication line outlet, a coolant inlet pipe, and a coolant pipe connection port. The vertical bracket is placed vertically, and multiple horizontal brackets are placed horizontally. The vertical bracket and the horizontal bracket are welded to form a frame structure. Bracket screws are installed on the horizontal brackets, and the bracket screws are connected to a first battery pack, a second battery pack, and a third battery pack. The partition is fixed between the horizontal brackets using partition screws. The lifting ring is welded to the upper ends of the vertical bracket and the horizontal bracket. The high-voltage and communication line connection port is led out by drilling a hole at the partition. The coolant pipe connection port is led out by drilling a hole at the partition. The first battery pack, the second battery pack, and the third battery pack are vertically distributed in space and are fixed to the horizontal brackets by bracket screws. The positive electrode, negative electrode, coolant outlet, coolant inlet, and communication port of the first battery pack are led out by drilling holes in the first battery pack. The positive electrode, negative electrode, coolant outlet, coolant inlet, and communication port of the second battery pack are led out by drilling holes in the second battery pack. The positive electrode, negative electrode, coolant outlet, coolant inlet, and communication port of the third battery pack are led out by drilling holes in the third battery pack. The two ends of the high-voltage positive wire are respectively connected to a high-voltage positive port and the positive electrode of the first battery pack. The two ends of the first intermediate wire are respectively connected to the negative electrode of the first battery pack and the positive electrode of the second battery pack. The negative electrode of the second battery pack and the positive electrode of the third battery pack are respectively connected to the two ends of the second intermediate wire. The two ends of the high-voltage negative wire are respectively connected to the negative electrode of the third battery pack and the high-voltage negative port. The two ends of the coolant outlet pipe are respectively connected to the coolant outlet of the first battery pack and the coolant inlet. The two ends of the first intermediate coolant pipe are respectively connected to the coolant inlet of the first battery pack and the coolant outlet of the second battery pack. The coolant inlet of the second battery pack and the coolant outlet of the third battery pack are respectively connected to the two ends of the second intermediate coolant pipe. The two ends of the coolant inlet pipe are respectively connected to the coolant inlet of the third battery pack and the coolant outlet. The two ends of the communication line outlet are respectively connected to the communication port of the first battery pack and the communication outlet port. The communication port of the first battery pack and the communication port of the second battery pack are respectively connected to the two ends of the first intermediate communication line. The communication port of the second battery pack and the communication port of the third battery pack are respectively connected to the two ends of the second intermediate communication line. The two ends of the communication line inlet are respectively connected to the communication port of the third battery pack and the communication inlet port. The high-voltage positive port, the high-voltage negative port, the communication outlet port, and the communication inlet port jointly pass through the high-voltage and communication line connection port to connect to the outside. The coolant pipe connection port is connected to a coolant inlet and a coolant outlet.

[0010] Preferably, in the step of determining the power requirements of the traveling system, lifting system, thermal management system, and low-voltage system of the heavy-duty electric forklift and calculating the total power requirement of the heavy-duty electric forklift, the total power requirement of the vehicle is the sum of the power requirements of the traveling system, lifting system, thermal management system, and low-voltage system, that is:

[0011] P all = P drive + P lift + P heat + P low

[0012] wherein, P all is the total power requirement of the heavy-duty electric forklift, P drive is the power requirement of the traveling system, P lift is the power requirement of the lifting system, P heat is the power requirement of the thermal management system, P low is the power requirement of the low-voltage system, P drive and P lift are determined by the design performance of the vehicle; P heat and P low are determined by the selection of the vehicle's thermal management equipment and the selection of the low-voltage system equipment.

[0013] Preferably, in the step of determining the power requirements of the traveling system, lifting system, thermal management system, and low-voltage system of the heavy-duty electric forklift and calculating the total power requirement of the heavy-duty electric forklift, the power requirement of the traveling system of the heavy-duty electric forklift takes the maximum value among the power requirements of the vehicle at full load and maximum speed, the power requirement of the vehicle at full load and acceleration, and the power requirement of the vehicle at full load and climbing, that is:

[0014]

[0015] wherein, P deivemax is the maximum power requirement of the drive motor, λ is the allowable overload coefficient of the drive motor, P d1 is the power requirement of the vehicle at full load and maximum speed, P d2 is the power requirement of the vehicle at full load and acceleration, P d3 is the power requirement of the vehicle at full load and climbing;

[0016] The power requirement of the vehicle at full load and maximum speed is calculated by the following formula:

[0017]

[0018] wherein, M is the full load mass of the vehicle, g is the acceleration due to gravity, f is the wheel rolling resistance coefficient, C D is the vehicle air resistance coefficient, A is the vehicle frontal area, vmax is the maximum design speed of the vehicle when fully loaded on a flat road, and η T is the transmission efficiency of the vehicle running system.

[0019] Preferably, in the steps of determining the power requirements of the running system, lifting system, thermal management system, and low-voltage system of the heavy-duty electric forklift, and calculating the total power requirement of the heavy-duty electric forklift, the process of the vehicle accelerating from full load to the maximum speed is represented by the following formula:

[0020]

[0021] where v max is the maximum design speed of the vehicle, and t m is the time required for acceleration;

[0022] Without considering air resistance, the power required for the vehicle to accelerate from full load to the maximum speed in the shortest time is not less than the sum of the rolling resistance power and the acceleration resistance power, and at the end moment of the acceleration process, the required power reaches the maximum, that is:

[0023]

[0024] where d t is the calculation step, and δ is the conversion coefficient of the rotating mass.

[0025] Preferably, in the steps of determining the power requirements of the running system, lifting system, thermal management system, and low-voltage system of the heavy-duty electric forklift, and calculating the total power requirement of the heavy-duty electric forklift, calculating the power requirement for climbing a slope fully loaded, on the maximum slope, the power required for the vehicle to travel at a constant speed in the fully loaded state is not less than the sum of the rolling resistance power and the ramp resistance power, that is:

[0026]

[0027] where v d3 is the design driving speed of the vehicle under the maximum slope when fully loaded, and α max is the maximum slope;

[0028] Calculating the power requirement of the lifting system, the pump motor power should meet the power required for the forklift to lift the goods at the maximum speed in the fully loaded state, that is:

[0029]

[0030] where M lift is the total weight of the lifting fork and the load, v liftmax is the maximum lifting speed of the forklift in the fully loaded state, and η h is the efficiency of the hydraulic system.

[0031] Preferably, in the steps of determining the power requirements of the traveling system, the lifting system, the thermal management system, and the low-voltage system of the heavy-duty electric forklift and calculating the total power requirement of the heavy-duty electric forklift, in addition to the conventional motor and battery cooling system, the cabin heating and battery heating systems are turned on in winter, and the air-conditioning system thermal management system is turned on in summer. The power requirement of the thermal management system is taken as the maximum value of the power requirement of the thermal management system in winter and the power requirement of the thermal management system in summer, that is:

[0032] P heat =max(P hw ,P hs )

[0033] Wherein, P hw is the power of the thermal management system in winter, and P hs is the power of the thermal management system in summer.

[0034] Preferably, in the steps of determining the target energy of the heavy-duty electric forklift battery according to the total power requirement, the traveling system power requirement, the lifting system power requirement, the thermal management system power requirement, and the low-voltage system power requirement of the heavy-duty electric forklift, the traveling system power requirement is represented by the power requirement of the drive motor. The power requirement of the motor in the heavy-duty electric forklift is expressed by the following formula:

[0035]

[0036] Wherein, P M is the power requirement of the motor of the heavy-duty electric forklift, P lift is the power requirement of the pump motor, P drive is the power requirement of the traveling motor, η lift is the efficiency of the lifting motor, η drive is the efficiency of the traveling motor, and JC% is the load duration rate, which refers to the proportion of the pump motor in the working time of the two motors.

[0037] Preferably, the target energy of the heavy-duty electric forklift battery is expressed as

[0038] E Battery =C Battery U Battery

[0039] Wherein, E Battery is the target energy of the heavy-duty electric forklift battery, U Battery is the nominal voltage of the battery, and C Battery is the capacity of the heavy-duty electric forklift battery.

[0040] Preferably, in the step of supplying power to the heavy-duty electric forklift by matching the capacity of the battery basic unit, the number of parallel-connected battery basic units, and the voltage of the battery basic unit according to the target energy of the heavy-duty electric forklift battery, the voltage of the battery basic unit is calculated by the following formula:

[0041] U Battery =U M =nU Pack

[0042] Wherein, U Pack is the nominal voltage of the battery pack, and n is the number of series-connected battery packs;

[0043] The capacity of the heavy-duty electric forklift battery is the sum of the capacities of multiple battery basic units, that is:

[0044]

[0045] Wherein, C Batteryunit is the capacity of the battery basic unit, and m is the number of parallel-connected battery basic units;

[0046] The matched heavy-duty electric forklift battery energy meets the target energy of the heavy-duty electric forklift battery, that is:

[0047] mC Battery unit U Battery ≥E Battery

[0048] Among the parameters of the battery basic unit to be selected, the capacity of the battery basic unit, the number of parallel-connected battery basic units, and the voltage of the battery basic unit are matched.

[0049] The method for matching the battery power of a heavy-duty electric forklift based on working condition requirements provided by the present invention makes the battery power redundant with respect to the required power of the forklift. The discharge rate of the battery during use is small, and the service life is improved; due to the split layout, the battery can be dispersed in the vehicle, greatly improving the space flexibility, and it is easy to load and unload and maintain; during the research and development and manufacturing process of cross-tonnage electric forklifts, the pre-designed battery basic units can be used in batches, saving the development cycle and manufacturing cost; if a single battery basic unit fails, other battery basic units can continue to discharge and be used. In this process, only the full-power operation of the forklift is restricted, and the battery can supply power to the vehicle using the limited current to ensure the autonomous operation of the vehicle to the maintenance area. Description of the Drawings

[0050] Figure 1 is a schematic diagram of the solution of the method for matching the battery power of a heavy-duty electric forklift based on working condition requirements provided by an embodiment of the present invention;

[0051] Figure 2 is a schematic diagram of the external structure of the battery basic unit provided by an embodiment of the present invention;

[0052] Figure 3 Schematic diagram of the internal structure of the battery basic unit provided by the embodiment of the present invention;

[0053] Figure 4 Flowchart of the battery power matching method for heavy-duty electric forklifts based on working condition requirements provided by the embodiment of the present invention.

[0054] Reference numerals: 1, vertical bracket; 2, horizontal bracket; 3, partition; 4, lifting ring; 5, bracket screw; 6, partition screw; 7, high-voltage and communication line connection port; 8, coolant pipeline connection port; 101, first battery pack; 102, second battery pack; 103, third battery pack; 104, positive electrode of the first battery pack; 105, negative electrode of the first battery pack; 106, coolant outlet of the first battery pack; 107, coolant inlet of the first battery pack; 108, communication port of the first battery pack; 109, positive electrode of the second battery pack; 110, negative electrode of the second battery pack; 111, coolant outlet of the second battery pack; 112, coolant inlet of the second battery pack; 113, communication port of the second battery pack; 114, positive electrode of the third battery pack; 115, negative electrode of the third battery pack; 116, coolant outlet of the third battery pack; 117, coolant inlet of the third battery pack; 118, communication port of the third battery pack; 119, high-voltage positive wire; 120, first intermediate wire; 121, second intermediate wire; 122, high-voltage negative wire; 123, high-voltage positive port; 124, high-voltage negative port; 125, coolant outlet pipe; 126, first intermediate coolant pipe; 127, second intermediate coolant pipe; 128, coolant inlet pipe; 129, coolant inlet; 130, coolant outlet; 131, communication line outlet; 132, first intermediate communication line; 133, second intermediate communication line; 134, communication line inlet; 135, communication outlet port; 136, communication inlet port. Detailed implementation manners

[0055] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0056] It can be understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but unless otherwise specified, these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of this application, the first xx script may be referred to as the second xx script, and similarly, the second xx script may be referred to as the first xx script.

[0057] Such as Figure 1 AndFigure 4 As shown in the figure, it is a method for matching the battery power of a heavy-duty electric forklift based on working conditions requirements provided by an embodiment of the present invention. The method includes:

[0058] S101. Determine the power requirements of the traveling system, lifting system, thermal management system, and low-voltage system of the heavy-duty electric forklift, and calculate the total power requirement of the heavy-duty electric forklift.

[0059] In this step, the operating conditions of the heavy-duty electric forklift can be divided into single design conditions and combined conditions. The single design conditions are divided into 6 conditions: fork lifting, fork translation, fork tilting, vehicle acceleration, vehicle deceleration, and steering; the combined condition is the situation where multiple single design conditions work simultaneously.

[0060] Total power requirement of the heavy-duty electric forklift:

[0061] According to the operating conditions, the heavy-duty electric forklift needs to design a lifting system and a traveling system, plus the necessary thermal management system and low-voltage system of the vehicle.

[0062] Therefore, the total power requirement of the vehicle is the sum of the power requirements of the traveling system, lifting system, thermal management system, and low-voltage system, that is:

[0063] P all = P drive + P lift + P heat + P low

[0064] Among them, P all is the total power requirement of the heavy-duty electric forklift, P drive is the power requirement of the traveling system, P lift is the power requirement of the lifting system, P heat is the power requirement of the thermal management system, P low is the power requirement of the low-voltage system. P drive and P lift are determined by the design performance of the vehicle; P heat and P low are determined by the selection of vehicle thermal management equipment and the selection of low-voltage system equipment.

[0065] Power requirement of the traveling system of the heavy-duty electric forklift:

[0066] All the power of the traveling system is provided by the drive motor. The drive motor needs to provide the power required to maintain the vehicle's maximum speed, maximum acceleration, and climbing. At the same time, the drive motor will also provide energy recovery power to the battery in the reverse direction, but its power is less than the vehicle's maximum acceleration power.

[0067] Therefore, the power demand of the traveling system of the heavy-duty electric forklift is the maximum of the three power demands (the power demand at the maximum full-load vehicle speed, the power demand for full-load vehicle acceleration, and the power demand for full-load vehicle climbing), that is:

[0068]

[0069] Among them, P deivemax is the maximum power demand of the drive motor, λ is the allowable overload coefficient of the drive motor, P d1 is the power demand at the maximum full-load vehicle speed, P d2 is the power demand for full-load vehicle acceleration, P d3 is the power demand for full-load vehicle climbing.

[0070] The power demand at the maximum full-load vehicle speed can be calculated by the following formula:

[0071]

[0072] Among them, M is the full-load mass of the vehicle, g is the acceleration due to gravity, f is the wheel rolling resistance coefficient, C D is the vehicle air resistance coefficient, A is the vehicle frontal area, v max is the maximum full-load design vehicle speed on flat road, η T is the transmission efficiency of the vehicle traveling system.

[0073] Calculation of full-load acceleration power:

[0074] The acceleration performance of the heavy-duty electric forklift is generally measured by the length of time required for the vehicle to accelerate to a specified speed. The shorter the acceleration time, the better, but the required peak power is also greater. The process of the full-load vehicle accelerating to the maximum speed can be expressed by the following formula:

[0075]

[0076] Among them, v max is the maximum design vehicle speed of the vehicle, t m is the time required for acceleration.

[0077] Without considering air resistance, the power required for the shortest time for the full-load vehicle to accelerate to the maximum speed should not be less than the sum of the rolling resistance power and the acceleration resistance power, and at the end moment of the acceleration process, the required power reaches the maximum, that is:

[0078]

[0079] Among them, d t is the calculation step size, generally taking 0.1 can meet the calculation accuracy, and δ is the conversion coefficient of the rotating mass.

[0080] Power demand for full-load climbing:

[0081] On the maximum gradient, the power required for the vehicle to travel at a constant speed under full load shall not be less than the sum of the rolling resistance power and the gradient resistance power, i.e.:

[0082]

[0083] where v d3 is the designed driving speed of the vehicle under full load at the maximum gradient, and α max is the maximum gradient.

[0084] Lifting system power requirement:

[0085] The power of the lifting system of a heavy-duty electric forklift is entirely provided by the pump motor. During the fork lifting, fork translation, fork tilting, and combined working conditions, the pump motor drives or drags the hydraulic pump in reverse, and the hydraulic pump delivers or unloads hydraulic oil to the hydraulic cylinder, thereby driving the fork to achieve the actions of the above-mentioned working conditions. At the same time, the pump motor will also provide energy recovery power to the battery in reverse, but its power is less than the motor power during the lifting working condition.

[0086] Therefore, the power of the pump motor shall meet the power required to lift the goods at the maximum speed under the full load state of the forklift, i.e.:

[0087]

[0088] where M lift is the total weight of the lifting fork and the load, v liftmax is the maximum lifting speed under the full load state of the forklift, and η h is the efficiency of the hydraulic system.

[0089] Thermal management system power requirement:

[0090] In addition to the conventional motor and battery cooling systems, a heavy-duty electric forklift turns on the cabin heating and battery heating systems in winter and the air-conditioning system thermal management system in summer. Therefore, the power requirement of the thermal management system is the maximum value of the power requirement of the thermal management system in winter and the power requirement of the thermal management system in summer, i.e.:

[0091] P heat = max(P hw , P hs )

[0092] where P hw is the power of the thermal management system in winter, and P hs is the power of the thermal management system in summer.

[0093] S102. Determine the target energy of the battery of the heavy-duty electric forklift according to the total power requirement, walking system power requirement, lifting system power requirement, thermal management system power requirement, and low-voltage system power requirement of the heavy-duty electric forklift.

[0094] In this step, the power requirements of the walking system and the lifting system can be represented by the power requirements of the drive motor and the pump motor respectively. The working types of the two motors are different in the working conditions of the heavy-duty electric forklift, and the working durations are also different. The power requirements of the motors in the heavy-duty electric forklift can be expressed by the following formula:

[0095]

[0096] where P M is the power requirement of the motor of the heavy-duty electric forklift, P lift is the power requirement of the pump motor, P drive is the power requirement of the walking motor, η lift is the efficiency of the lifting motor, η drive is the efficiency of the walking motor. JC% is the load duration rate, specifically referring to the proportion of the pump motor in the working time of the two motors. For the standard working condition cycle of the heavy-duty electric forklift, JC% is about 15%.

[0097] During the operation of the heavy-duty electric forklift, the battery is the only energy source. The energy source of the forklift should meet the continuous operation of the motor for 2.5 hours, and should also meet the continuous operation of the thermal management system and the low-voltage system for 8 hours. Therefore, the rated capacity of the battery pack:

[0098]

[0099] where C Battery is the battery capacity of the heavy-duty electric forklift, t M is the working duration of the motor, U M is the rated voltage of the motor, t heat is the working duration of the thermal management system, U heat is the rated voltage of the thermal management system, t low is the working duration of the low-voltage system, U low is the rated voltage of the low-voltage system.

[0100] The target energy of the battery of the heavy-duty electric forklift can be expressed by the following formula:

[0101] E Battery = C Battery U Battery

[0102] where E Battery is the target energy of the battery of the heavy-duty electric forklift, U Battery is the nominal voltage of the battery.

[0103] S103. According to the target energy of the battery of the heavy-duty electric forklift, match the capacity of the battery basic unit, the number of parallel connections of the battery basic unit, and the voltage of the battery basic unit to supply power to the heavy-duty electric forklift.

[0104] In this step, the parameters related to the basic battery unit are the basic battery unit voltage and the basic battery unit capacity. Since the multiple basic battery units work in parallel in the heavy-duty electric forklift, the basic battery unit voltage is the nominal voltage of the heavy-duty electric forklift battery. Generally, the nominal voltage of the heavy-duty electric forklift battery matches the rated voltages of the drive motor and the pump motor. At the same time, the basic battery unit is formed by connecting multiple battery packs in series. The basic battery unit voltage can be calculated by the following formula:

[0105] U Battery =U M =nU Pack

[0106] Wherein, U Pack is the nominal voltage of the battery pack, and n is the number of battery packs connected in series.

[0107] Since the basic battery unit works in parallel in the heavy-duty electric forklift, the capacity of the heavy-duty electric forklift battery is the sum of the capacities of multiple basic battery units, that is:

[0108]

[0109] Wherein, C Batteryunit is the basic battery unit capacity, and m is the number of basic battery units connected in parallel.

[0110] The energy of the heavy-duty electric forklift battery to be matched should meet the target energy of the heavy-duty electric forklift battery, that is:

[0111] mC Battery unit U Battery ≥E Battery

[0112] Finally, among the parameters of the basic battery unit to be selected, match the basic battery unit capacity, the number of basic battery units connected in parallel, and the basic battery unit voltage.

[0113] In this embodiment, as Figure 1 shown, the split battery is composed of multiple basic battery units connected in parallel. When the heavy-duty electric forklift is working, the battery power is transmitted to the power distribution unit. Subsequently, the power distribution unit distributes the power to the drive motor controller, the pump motor controller, the DC / DC, and the thermal management system.

[0114] The drive motor controller transmits the power to the drive motor. The drive motor converts the electric power into mechanical work, provides the required torque and required speed for the drive axle and the vehicle, and enables the vehicle running system to work. The pump motor controller transmits the power to the pump motor, and the pump motor drives the hydraulic lifting system, the hydraulic braking system, and the power steering system, enabling the vehicle hydraulic system to work. The DC / DC transmits the power to the low-voltage system, enabling the vehicle low-voltage system to work.

[0115] The basic battery unit is formed by connecting multiple battery packs in series. Here, taking the series connection of three battery packs as an example, the mechanical and electrical structures of the basic battery unit are described. Figure 2 It is a schematic diagram of the external structure of the basic battery unit. Figure 3 It is a schematic diagram of the internal structure of the basic battery unit.

[0116] As Figure 2 and Figure 3 shown, the basic battery unit mainly consists of a vertical bracket 1, a horizontal bracket 2, a partition 3, a lifting ring 4, bracket screws 5, partition screws 6, a high-voltage and communication line connection port 7, a coolant pipeline connection port 8, a first battery pack 101, a second battery pack 102, a third battery pack 103, a positive electrode of the first battery pack 104, a negative electrode of the first battery pack 105, a coolant outlet of the first battery pack 106, a coolant inlet of the first battery pack 107, a communication port of the first battery pack 108, a positive electrode of the second battery pack 109, a negative electrode of the second battery pack 110, a coolant outlet of the second battery pack 111, a coolant inlet of the second battery pack 112, a communication port of the second battery pack 113, a positive electrode of the third battery pack 114, a negative electrode of the third battery pack 115, a coolant outlet of the third battery pack 116, a coolant inlet of the third battery pack 117, a communication port of the third battery pack 118, a high-voltage positive wire 119, a first intermediate wire 120, a second intermediate wire 121, a high-voltage negative wire 122, a high-voltage positive port 123, a high-voltage negative port 124, a coolant outlet pipe 125, a first intermediate coolant pipe 126, a second intermediate coolant pipe 127, a coolant inlet pipe 128, a coolant inlet 129, a coolant outlet 130, a communication wire outlet 131, a first intermediate communication wire 132, a second intermediate communication wire 133, a communication wire inlet 134, a communication outlet port 135, and a communication inlet port 136.

[0117] Four vertical brackets 1 are placed vertically, and multiple horizontal brackets 2 are placed horizontally. The vertical brackets 1 and the horizontal brackets 2 are welded to form a frame structure. Three horizontal brackets 2 are installed on the front. The bracket screws 5 are installed on the side horizontal brackets 2 and are connected to the first battery pack 101, the second battery pack 102, and the third battery pack 103. Four horizontal brackets are installed on the side. The partition 3 is fixed between two horizontal brackets using partition screws 6. The lifting rings 4 are welded to the upper ends of the vertical brackets 1 and the horizontal brackets 2. The high-voltage and communication line connection ports 7 are led out by drilling holes in the front partition 3. The coolant pipeline connection ports 8 are led out by drilling holes in the front partition. The first battery pack 101, the second battery pack 102, and the third battery pack 103 are vertically distributed in space and are fixed to the horizontal brackets 2 by the bracket screws 5. The positive electrode 104 of the first battery pack, the negative electrode 105 of the first battery pack, the coolant outlet 106 of the first battery pack, the coolant inlet 107 of the first battery pack, and the communication port 108 of the first battery pack are led out by drilling holes in the first battery pack 101. The positive electrode 109 of the second battery pack, the negative electrode 110 of the second battery pack, the coolant outlet 111 of the second battery pack, the coolant inlet 112 of the second battery pack, and the communication port 113 of the second battery pack are led out by drilling holes in the second battery pack 102. The positive electrode 114 of the third battery pack, the negative electrode 115 of the third battery pack, the coolant outlet 116 of the third battery pack, the coolant inlet 117 of the third battery pack, and the communication port 118 of the third battery pack are led out by drilling holes in the third battery pack 103. Both ends of the high-voltage positive wire 119 are respectively connected to the high-voltage positive port 123 and the positive electrode 104 of the first battery pack. Both ends of the first intermediate wire 120 are respectively connected to the negative electrode 105 of the first battery pack and the positive electrode 109 of the second battery pack. Both ends of the second intermediate wire 121 are respectively connected to the negative electrode 110 of the second battery pack and the positive electrode 114 of the third battery pack. Both ends of the high-voltage negative wire 122 are respectively connected to the negative electrode 115 of the third battery pack and the high-voltage negative port 124. Both ends of the coolant outlet pipe 125 are respectively connected to the coolant outlet 106 of the first battery pack and the coolant inlet 129. Both ends of the first intermediate coolant pipe 126 are respectively connected to the coolant inlet 107 of the first battery pack and the coolant outlet 111 of the second battery pack. Both ends of the second intermediate coolant pipe 127 are respectively connected to the coolant inlet 112 of the second battery pack and the coolant outlet 116 of the third battery pack. Both ends of the coolant inlet pipe 128 are respectively connected to the coolant inlet 117 of the third battery pack and the coolant outlet 130. Both ends of the communication line outlet 131 are respectively connected to the communication port 108 of the first battery pack and the communication outlet port 135. Both ends of the first intermediate communication line 132 are respectively connected to the communication port 108 of the first battery pack and the communication port 113 of the second battery pack. Both ends of the second intermediate communication line 133 are respectively connected to the communication port 113 of the second battery pack and the communication port 118 of the third battery pack. Both ends of the communication line inlet 134 are respectively connected to the communication port 118 of the third battery pack and the communication inlet port 136.The high-voltage positive electrode port 123, high-voltage negative electrode port 124, communication outgoing line port 135 and communication incoming line port 136 jointly pass through the high-voltage and communication line connection port 7 to be connected to the outside. The coolant inlet 129 and the coolant outlet 130 are connected to the coolant pipeline connection port 8.

[0118] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heavy-duty electric forklift battery power matching method based on working condition requirements, characterized in that: The method comprises: Determine the power requirements of the heavy-duty electric forklift's travel system, lifting system, thermal management system, and low-voltage system, and calculate the total power requirements of the heavy-duty electric forklift; Determine the target energy of the heavy-duty electric forklift battery based on the total power demand of the heavy-duty electric forklift, the power demand of the travel system, the power demand of the lifting system, the power demand of the thermal management system, and the power demand of the low-voltage system; The heavy-duty electric forklift is powered by matching the capacity of the battery basic unit, the number of battery basic units in parallel, and the voltage of the battery basic unit according to the target energy of the heavy-duty electric forklift battery.

2. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 1 is characterized in that: The battery basic unit comprises a vertical support (1), a horizontal support (2), a partition (3), a lifting ring (4), a high-voltage and communication line connection port (7), a first intermediate wire (120), a high-voltage positive wire (119), a high-voltage negative wire (122), a first intermediate coolant pipe (126), a communication line inlet wire (134), a communication line outlet wire (131), a coolant inlet pipe (128) and a coolant line connection port (8); the vertical support (1) is placed vertically, a plurality of horizontal supports (2) are placed horizontally, the vertical support (1) and the horizontal support (2) are welded to form a frame structure, a support screw (5) is installed on the horizontal support (2), and the support screw (5) is connected to the first battery pack (101), The second battery pack (102) and the third battery pack (103), the partition (3) is fixed between the horizontal bracket (2) using the partition screw (6), the lifting ring (4) is welded to the upper end of the vertical bracket (1) and the horizontal bracket (2), the high-voltage and communication line connection port (7) is punched at the partition (3) to lead out, the coolant pipeline connection port (8) is punched at the partition (3) to lead out, the first battery pack (101), the second battery pack (102) and the third battery pack (103) are vertically distributed in space, and are fixed to the horizontal bracket (2) by the bracket screw (5), and the first battery pack (101) is punched with a hole to lead out the first battery pack positive electrode (104), the first battery pack negative electrode (105), and the first battery pack coolant outlet (106) 06), a first battery pack coolant inlet (107) and a first battery pack communication port (108), a second battery pack positive electrode (109), a second battery pack negative electrode (110), a second battery pack coolant outlet (111), a second battery pack coolant inlet (112) and a second battery pack communication port (113) are punched on the second battery pack (102), a third battery pack positive electrode (114), a third battery pack negative electrode (115), a third battery pack coolant outlet (116), a third battery pack coolant inlet (117) and a third battery pack communication port (118) are punched on the third battery pack (103), and the two ends of the high-voltage positive electrode wire (119) are respectively connected to the high-voltage positive electrode port (123) and The first battery pack positive electrode (104), the first intermediate conductor (120) is connected to the first battery pack negative electrode (105) and the second battery pack positive electrode (109) at both ends, the second battery pack negative electrode (110) and the third battery pack positive electrode (114) are connected to the second intermediate conductor (121) at both ends, the high-voltage negative electrode line (122) is connected to the third battery pack negative electrode (115) and the high-voltage negative electrode port (124) at both ends, the coolant outlet pipe (125) is connected to the first battery pack coolant outlet (106) and the coolant inlet (129) at both ends, and the first intermediate coolant pipe (126) is connected to the first battery pack coolant inlet (107) and the second battery pack coolant outlet (111) at both ends,The second battery pack coolant inlet (112) and the third battery pack coolant outlet (116) are respectively connected to two ends of the second intermediate coolant pipe (127); two ends of the coolant inlet pipe (128) are respectively connected to the third battery pack coolant inlet (117) and the coolant outlet (130); two ends of the communication line outlet (131) are respectively connected to the first battery pack communication port (108) and the communication line outlet (135); the first battery pack communication port (108) and the second battery pack communication port (113) are respectively connected to two ends of the first intermediate communication line (132); The battery pack communication port (113) and the third battery pack communication port (118) are respectively connected to the two ends of the second intermediate communication line (133); the two ends of the communication line inlet (134) are respectively connected to the third battery pack communication port (118) and the communication inlet (136); the high-voltage positive electrode port (123), the high-voltage negative electrode port (124), the communication outlet port (135) and the communication inlet port (136) are connected to the outside through the high-voltage and communication line connection port (7); the coolant pipeline connection port (8) is connected to the coolant inlet (129) and the coolant outlet (130).

3. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 1 is characterized in that: In the step of determining the power requirements of the traveling system, the lifting system, the thermal management system and the low-voltage system of the heavy-duty electric forklift and calculating the total power requirements of the heavy-duty electric forklift, the total power requirements of the vehicle are the sum of the power requirements of the traveling system, the lifting system, the thermal management system and the low-voltage system, that is: P all =P drive +P lift +P heat +P low Among them, P all is the total power requirement of heavy-duty electric forklift, P drive is the power requirement of the traveling system, P lift is the lifting system power requirement, P heat is the thermal management system power requirement, P low is the low voltage system power demand, P drive and P lift Determined by vehicle design performance; P heat and P low Determined by the selection of vehicle thermal management equipment and low-voltage system equipment.

4. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 1 is characterized in that: In the step of determining the power requirements of the travel system, the lifting system, the thermal management system and the low-voltage system of the heavy-duty electric forklift and calculating the total power requirements of the heavy-duty electric forklift, the power requirement of the travel system of the heavy-duty electric forklift is the largest one among the power requirements of the maximum speed of the vehicle at full load, the power requirements of the acceleration of the vehicle at full load and the power requirements of the climbing of the vehicle at full load, that is: Among them, P deivemax is the maximum power requirement of the drive motor, λ is the allowable overload factor of the drive motor, P d1 is the maximum speed power requirement of the vehicle at full load, P d2 is the vehicle's full-load acceleration power requirement, P d3 The climbing power requirement of the vehicle when fully loaded; The power requirement of the vehicle at full load and maximum speed is calculated as follows: Where M is the fully loaded mass of the vehicle, g is the acceleration of gravity, f is the wheel rolling resistance coefficient, C D is the vehicle air resistance coefficient, A is the vehicle frontal area, v max is the maximum design speed of a fully loaded vehicle on a flat road, η T It is the transmission efficiency of the vehicle's traveling system.

5. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 4 is characterized in that: In the step of determining the power requirements of the traveling system, the lifting system, the thermal management system and the low-voltage system of the heavy-duty electric forklift and calculating the total power requirements of the heavy-duty electric forklift, the process of accelerating the vehicle to the maximum speed when fully loaded is represented by the following formula: Among them, v max is the maximum design speed of the vehicle, t m The time required for acceleration; Without considering air resistance, the power required for the vehicle to accelerate to the maximum speed in the shortest time when fully loaded is not less than the sum of the rolling resistance power and the acceleration resistance power, and at the end of the acceleration process, the required power reaches the maximum, that is: Among them, d t is used to calculate the step size, and δ is the rotational mass conversion factor.

6. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 4 is characterized in that: In the step of determining the power requirements of the travel system, the lifting system, the thermal management system and the low-voltage system of the heavy-duty electric forklift and calculating the total power requirements of the heavy-duty electric forklift, the full-load climbing power requirement is calculated. On the maximum slope, the power required for the vehicle to travel at a constant speed under full load is not less than the sum of the rolling resistance power and the slope resistance power, that is: Among them, v d3 is the design speed of the vehicle at the maximum slope with full load, α max is the maximum slope; Calculate the power requirement of the lifting system. The pump motor power should meet the power required to lift the goods at the maximum speed when the forklift is fully loaded, that is: Among them, M lift is the total weight of the lifting fork and the load, v liftmax is the maximum lifting speed of the forklift when fully loaded, η h For hydraulic system efficiency.

7. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 4 is characterized in that: In the step of determining the power requirements of the travel system, lifting system, thermal management system and low-voltage system of the heavy-duty electric forklift and calculating the total power requirements of the heavy-duty electric forklift, in addition to the conventional motor and battery cooling system, the heavy-duty electric forklift turns on the cabin heating and battery heating systems in winter, and turns on the air conditioning system thermal management system in summer. The power requirement of the thermal management system takes the maximum value of the power requirements of the thermal management system in winter and the power requirements of the thermal management system in summer, that is: P heat =max(P hw ,P hs ) Among them, P hw is the winter thermal management system power, P hs It is the thermal management system power in summer.

8. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 1 is characterized in that: In the step of determining the target energy of the heavy-duty electric forklift battery according to the total power demand of the heavy-duty electric forklift, the power demand of the travel system, the power demand of the lifting system, the power demand of the thermal management system and the power demand of the low-voltage system, the power demand of the travel system is represented by the power demand of the drive motor, and the power demand of the motor in the heavy-duty electric forklift is represented by the following formula: Among them, P M is the power requirement of heavy-duty electric forklift motor, P lift is the pump motor power requirement, P drive is the power requirement of the travel motor, η lift is the efficiency of the lifting motor, η drive is the travel motor efficiency, and JC% is the duty cycle, which refers to the proportion of the pump motor in the working time of the two motors.

9. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 1 is characterized in that: The target energy of heavy-duty electric forklift battery is expressed as E Battery =C Battery U Battery Among them, E Battery Target energy for heavy-duty electric forklift batteries, U Battery is the nominal voltage of the battery, C Battery Battery capacity for heavy-duty electric forklifts.

10. The heavy-duty electric forklift battery power matching method based on working condition requirements according to claim 1, characterized in that: According to the target energy of the heavy-duty electric forklift battery, the capacity of the battery basic unit, the number of battery basic units in parallel and the voltage of the battery basic unit, in the step of powering the heavy-duty electric forklift, the battery basic unit voltage is calculated by the following formula: YOU Battery =You M =nU Pack Among them, U Pack is the nominal voltage of the battery pack, and n is the number of battery packs connected in series; The battery capacity of a heavy-duty electric forklift is the sum of the capacities of multiple battery basic units, namely: Among them, C Batteryunit is the capacity of the basic battery unit, m is the number of basic battery units connected in parallel; The energy of the matched heavy-duty electric forklift battery meets the target energy of the heavy-duty electric forklift battery, namely: mC Battery unit U Battery ≥E Battery Among the battery basic unit parameters to be selected, match the battery basic unit capacity, the number of battery basic units connected in parallel, and the battery basic unit voltage.

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