High-voltage lithium battery forklift temperature self-adaptive control method and forklift

Abstract

The application discloses a high-voltage lithium battery temperature self-adaptive control method and a forklift, and belongs to the technical field of electric forklift heat management. The application collects battery, motor electric control and hydraulic oil temperature signals through multiple temperature sensors, divides two working conditions of operation and charging, sets graded temperature thresholds, and gives the highest priority to battery temperature control. The operation condition adopts PID dynamic adjustment of a double-independent water cooling loop water pump and a shared double-cavity water tank variable frequency fan, and the hydraulic oil adopts natural air cooling plus active fan composite heat dissipation. The charging condition starts the battery heating module for preheating at low temperature and adopts water cooling heat dissipation at high temperature. The forklift is provided with an integrated double-cavity heat dissipation water tank with a sealing partition plate, the battery and the motor electric control water cooling loop are mutually isolated, and the frame and the counterweight cooperate to form an integrated heat dissipation air duct. The application realizes multi-component cooperative closed-loop adaptive temperature control, avoids heat dissipation mutual interference, reduces energy consumption, adapts to fast charging demand, prolongs the service life of lithium batteries, and is suitable for heavy working condition continuous operation high-voltage lithium battery forklifts.

Description

Technical Field

[0001] This invention relates to the field of thermal management control technology for electric forklifts, specifically to a high-voltage lithium battery forklift temperature adaptive control method and forklift based on multi-component temperature collaborative sensing. Background Technology

[0002] Existing high-pressure lithium-ion battery forklift cooling and temperature control technologies still have many shortcomings, making it difficult to meet actual operational needs: First, in most solutions, the battery and motor / control system share a cooling circuit or lack effective isolation, leading to mutual interference in heat dissipation and an inability to stably maintain a suitable operating temperature range for the battery, thus affecting battery life and increasing total lifecycle costs; Second, the cooling control of the motor / control system and the hydraulic system is independent, lacking a unified collaborative control logic and priority division, easily resulting in an imbalance where critical components experience insufficient cooling and non-critical components experience excessive cooling, leading to energy waste; Third, the hydraulic system relies heavily on natural air cooling, which is insufficient under high-load conditions, causing the oil temperature to rise too quickly and affecting the sealing performance and operational stability of the hydraulic system; Fourth, temperature control strategies are mostly fixed-threshold on / off controls, unable to dynamically adjust the heat dissipation intensity based on the real-time temperature of components, resulting in low temperature control accuracy and high energy consumption. Fifth, in fast charging scenarios, lithium batteries have stricter requirements for temperature control. However, existing technologies generally do not incorporate charging temperature control into the vehicle's thermal management closed loop. During charging, the battery temperature rise cannot be quickly suppressed, or the battery temperature is high when the vehicle has just finished operating. This makes it difficult to meet the strict requirements of high-voltage fast charging for the temperature range, resulting in extended charging time and reduced continuous operation efficiency.

[0003] Furthermore, existing multi-component collaborative heat dissipation solutions suffer from structural complexity. Some solutions employ a stacked arrangement of multiple water tanks and heat exchangers, resulting in complex structures, large space requirements, and high energy consumption. Control methods are mostly fixed threshold switching controls, lacking dynamic adjustment strategies based on temperature levels, leading to lag in response, significant energy waste, and difficulty in adapting to the frequent start-stop, variable load, and variable operating conditions of forklifts.

[0004] In summary, existing technologies are insufficient to simultaneously address the heat dissipation efficiency, temperature control accuracy, fast charging compatibility, and energy economy of high-voltage lithium-ion forklifts under heavy-duty continuous operation. There is an urgent need for a temperature adaptive control scheme with a reasonable structure, intelligent control, and clear priorities. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing high-voltage lithium battery forklift thermal management systems, such as mutual interference between battery and motor / electronic control heat dissipation, lack of coordinated priority in multi-system temperature control, insufficient hydraulic cooling capacity, low precision of fixed threshold control, and poor adaptability to fast charging temperature control. This invention provides a high-voltage lithium battery forklift temperature adaptive control method and forklift, which, through a dual-cavity independent water-cooling architecture, multi-component temperature collaborative sensing, hierarchical priority control, and adaptive closed-loop adjustment, simplifies the overall vehicle structure while achieving precise temperature control across heavy-duty operations and fast charging scenarios. This improves battery life and overall vehicle operational stability, and reduces heat dissipation energy consumption.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The high-voltage lithium battery forklift provided by the present invention includes a counterweight, a frame (front frame, upper intermediate frame, lower intermediate frame, and tail frame), a high-voltage lithium battery, a travel motor, a travel electronic control unit, a pump motor, a pump electronic control unit, a hydraulic oil tank, a central controller, a temperature sensor group, a dual-chamber cooling water tank (first chamber, second chamber, and water tank cooling fan), a battery-side water cooling circuit, a motor electronic control-side water cooling circuit, a battery-side water pump, a motor electronic control-side water pump, a hydraulic oil active cooling fan, a charging port, etc. The specific structure is as follows: the counterweight and the frame serve as core structural components, used to install and fix other parts.

[0007] The counterweight adopts a one-piece cast structure with a heat dissipation channel in the middle, and a protective net is installed outside the channel. The frame consists of four parts: the front frame, the upper middle frame, the lower middle frame, and the rear frame. The front frame is used to install the travel motor and travel electronic control; the rear frame is used to install components such as the dual-chamber radiator, the battery-side water pump, and the motor and electronic control-side water pump.

[0008] Furthermore, the intermediate frame is used to fix components such as the pump motor, pump control system, central controller, hydraulic oil tank, hydraulic oil active cooling fan, and charging port. The intermediate frame has no front baffle and can be directly connected to the outside; the rear baffle has a square hole in the middle, which, together with the dual-chamber radiator tank mounted on the tail frame and the heat dissipation channel in the middle of the counterweight, forms a complete air duct.

[0009] Furthermore, the rear baffle has multiple rectangular holes near the hydraulic oil tank for passive cooling of the hydraulic oil tank.

[0010] Furthermore, the lower part of the middle frame is the battery compartment, used to install and fix the high-voltage lithium battery.

[0011] Furthermore, the high-voltage lithium battery consists of a self-heating module that is electrically connected to the central controller. When charging under low-temperature conditions, it can heat the battery to keep the high-voltage lithium battery temperature within the ideal fast-charging temperature range.

[0012] Furthermore, the hydraulic oil tank is welded from steel plates and is located in the middle of the frame near the rear panel, where there are multiple rectangular holes, which can create air convection when the forklift is moving.

[0013] Furthermore, the central controller adopts a vehicle control unit (VCU) or a programmable logic controller (PLC), equipped with multi-channel analog input interfaces, capable of receiving standard signals output from the temperature sensor group. The central controller has built-in control algorithms that can automatically adjust the operating parameters of the battery-side water pump, the motor-controlled water pump, and the radiator cooling fan according to temperature deviations, achieving precise temperature control.

[0014] Furthermore, the temperature sensor group includes temperature sensors respectively installed on the high-voltage lithium battery, the walking motor, the walking electronic control, the pump motor, the pump electronic control, and the hydraulic oil tank. Each temperature sensor is electrically connected to the central controller to transmit the collected temperature signal to the central controller.

[0015] Furthermore, the dual-chamber cooling water tank adopts an integrated independent sealed structure, with the two chambers sharing a single cooling fan. The forced convection of the cooling fan enables simultaneous heat dissipation from both chambers.

[0016] Furthermore, the dual-chamber radiator is made of aluminum alloy, which is corrosion-resistant and has good thermal conductivity. The first and second chambers are separated by a sealed partition to prevent heat dissipation interference caused by coolant mixing.

[0017] Furthermore, the water tank cooling fan is a variable frequency fan, which can dynamically adjust the airflow according to temperature changes by the central controller. The first chamber of the dual-chamber cooling water tank is connected to the battery-side water cooling circuit to dissipate heat from the high-voltage lithium battery; the second chamber of the dual-chamber cooling water tank is connected to the motor and electronic control-side water cooling circuit. The travel motor, travel electronic control, pump motor, and pump electronic control are connected in series in the motor and electronic control-side water cooling circuit to achieve overall heat dissipation.

[0018] Furthermore, the battery-side water cooling circuit and the motor control-side water cooling circuit are each equipped with an independent battery-side water pump and a motor control-side water pump that support speed adjustment, and both are electrically connected to the central controller and are independently controlled by the central controller.

[0019] Furthermore, the hydraulic oil active cooling fan can be started or stopped via a switch. It is located on the air cooling channel of the hydraulic oil tank, which is situated on the middle frame of the forklift near the rear tailgate, in a position with multiple rectangular holes, creating air convection when the forklift is in motion. The hydraulic oil active cooling fan is electrically connected to the central controller, which controls its start and stop based on the hydraulic oil temperature.

[0020] The high-voltage lithium battery forklift temperature adaptive control method provided by this invention includes the following steps: Step 1: Temperature signal acquisition and transmission. Temperature sensors are installed on the high-voltage lithium battery, travel motor, travel electronic control, pump motor, pump electronic control and hydraulic oil tank of the forklift. Each temperature sensor acquires the temperature signal of the corresponding component in real time and transmits the temperature signal to the central controller.

[0021] Step 2: Temperature definition and signal processing. The central controller receives temperature signals transmitted from each temperature sensor, defines the high-voltage lithium battery temperature as T0, the combined temperature of the walking motor, walking electronic control, pump motor, and pump electronic control as T1, and the hydraulic oil temperature as T2.

[0022] Step 3: Setting preset temperature thresholds. The central controller has built-in preset temperature thresholds Adischarge, Acharge1, Acharge2, B, and C. Among them, Adischarge is the battery discharge heat dissipation enhancement threshold, Acharge1 is the battery charging preheating start threshold, Acharge2 is the battery charging preheating stop threshold, Acharge3 is the battery charging heat dissipation enhancement threshold, B is the heat dissipation enhancement threshold for the water cooling circuit on the motor control side, and C is the hydraulic oil active cooling fan start threshold. The thresholds satisfy the following hierarchical relationship: When the vehicle is in operation, A < B < C; When the vehicle is charging, Acharge1 < Acharge2 < Acharge3.

[0023] Step 4: Execution of hierarchical control logic. The central controller compares the collected T0, T1, and T2 values ​​with their corresponding preset thresholds, and outputs control commands to each heat dissipation actuator based on the comparison results. The specific control logic is as follows: First, the central controller collects the charging port connection signal and the vehicle key switch status in real time, and makes a comprehensive judgment on the current vehicle operating condition: if it detects that the charging port is physically connected and the charging communication signal is normal, and the vehicle key switch is in the off position, it is determined to be in charging condition; otherwise, it is determined to be in operating condition.

[0024] When the forklift is in operation, the central controller performs temperature control according to the following logic: Battery temperature control logic: The temperature sensor monitors the high-voltage lithium battery temperature T0 in real time. When T0 ≥ A discharge, the central controller outputs a control signal to the battery-side water pump and water tank cooling fan in the battery-side water cooling circuit. Based on the temperature deviation, the PID algorithm is used to calculate the control quantity and adjust the speed of the battery-side water pump and the duty cycle of the water tank cooling fan 1. The control objective is to stabilize the high-voltage lithium battery temperature within a suitable range to ensure optimal battery performance.

[0025] Motor and electronic control temperature control logic: Temperature sensors monitor the temperatures of the travel motor, travel electronic control unit, pump motor, and pump electronic control unit respectively. The central controller calculates the comprehensive temperature T1 (the average of the four temperatures). When T1 ≥ B, the central controller outputs control signals to the water pump and water tank cooling fan on the motor electronic control side of the water cooling circuit. Based on the temperature deviation, a PID algorithm is used to calculate the control quantity and adjust the duty cycle of the water pump speed and water tank cooling fan speed on the motor electronic control side. The control objective is to stabilize the temperatures of the travel motor, travel electronic control unit, pump motor, and pump electronic control unit within a suitable range to ensure optimal forklift operation performance.

[0026] Hydraulic oil temperature control logic: The temperature sensor monitors the hydraulic oil temperature T2. When T2 ≥ C, the central controller outputs a switch signal to start the hydraulic oil active cooling fan, which continues to run. The hydraulic oil tank is located on the middle frame of the forklift, near the rear panel, in a position with multiple rectangular holes. When the forklift is moving, air convection is formed. The activation of the hydraulic oil active cooling fan can be superimposed with natural convection, significantly improving the heat dissipation effect.

[0027] When the forklift is in charging mode, the central controller performs temperature control according to the following logic: Preheating control before charging: The temperature sensor monitors the high-voltage lithium battery temperature T0. When T0 < A-charge 1, the central controller outputs a switch signal to the high-voltage lithium battery heating module, the heating module starts, and uses the battery's own residual power to preheat the battery. When the high-voltage lithium battery temperature T0 ≥ A-charge 2, the central controller outputs a switch signal to the high-voltage lithium battery heating module, the heating module turns off, and the normal charging process begins.

[0028] Temperature control during charging: During charging, the central controller monitors the high-voltage lithium battery temperature T0 in real time. When T0 ≥ A3, the central controller outputs a control signal to the battery-side water pump and water tank cooling fan in the battery-side water cooling circuit. Based on the temperature deviation, the PID algorithm is used to calculate the control quantity and adjust the duty cycle of the battery-side water pump speed and the water tank cooling fan speed to stabilize the high-voltage lithium battery temperature within a suitable range.

[0029] Step 5: Closed-loop control and dynamic adjustment. The central controller receives temperature signals from each temperature sensor in real time and dynamically adjusts the operating parameters of each heat dissipation actuator to form closed-loop control and achieve adaptive balance of temperature of multiple components.

[0030] Compared with the prior art, the main technical innovations of this invention include: 1) Multi-component temperature collaborative sensing and hierarchical control: By arranging temperature sensors on components such as high-voltage lithium batteries, walking motors, walking electronic controls, pump motors, pump electronic controls, and hydraulic oil tanks, comprehensive sensing of the thermal state of the entire machine is achieved; a hierarchical control strategy is adopted, based on the priority relationship of A discharge < B < C when the vehicle is in operation, and A charge 1 < A charge 2 < A charge 3 when the vehicle is in charging, to ensure that battery temperature control has the highest priority, ensuring the temperature stability of the battery during charging and discharging, which can effectively improve battery life, reduce the total life cycle cost, and shorten the operation cycle; 2) Dual-cavity independent water cooling design: The dual-cavity heat dissipation water tank is adopted, and the water cooling circuit on the battery side and the water cooling circuit on the motor and electronic control side are independent of each other, avoiding the heat dissipation interference problem caused by the shared circuit between the battery and the motor and electronic control in the traditional solution; the two cavities share a fan, which simplifies the structural design and saves space while ensuring heat dissipation effect; 3) Hydraulic oil active + passive composite air cooling: The hydraulic oil tank is located on the middle frame of the forklift near the rear panel, where multiple rectangular holes are opened, allowing air convection to occur when the forklift is in motion. When the oil temperature rises, the hydraulic oil active cooling fan starts, which, combined with natural convection, forms composite air cooling, significantly improving heat dissipation efficiency. This design ensures both effective heat dissipation and reduced energy consumption. 4) Adaptive closed-loop control strategy: A temperature feedback-based closed-loop control is adopted, allowing the central controller to dynamically adjust the operating parameters of each cooling actuator according to real-time temperature changes. Precise temperature regulation is achieved through PID control algorithms, avoiding the response lag problem of traditional fixed threshold control. Attached Figure Description

[0031] Figure 1 This is a logic block diagram of the temperature adaptive control method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a forklift layout scheme according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the main structure of the forklift according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a dual-cavity cooling water tank according to an embodiment of the present invention; In the diagram: 1-Dual-chamber cooling water tank, 1-1-First chamber, 1-2-Second chamber, 1-3-Water tank cooling fan, 2-Counterweight, 3-Battery-side water pump, 4-Hydraulic oil tank, 5-Hydraulic oil active cooling fan, 6-Frame, 6-1-Front frame, 6-21-Upper middle frame, 6-22-Lower middle frame, 6-3-Tail frame, 7-Temperature sensor group, 8-Walking motor, 9-Walking electronic control, 10-Motor electronic control side water cooling circuit, 11-Pump motor, 12-Pump electronic control, 13-High-voltage lithium battery, 14-Charging port, 15-Central controller, 16-Battery-side water cooling circuit, 17-Motor electronic control side water pump. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0034] like Figure 1-4 The high-voltage lithium battery forklift provided by the present invention includes a counterweight 2, a frame 6 (front frame 6-1, upper middle frame 6-21, lower middle frame 6-22, and tail frame 6-3), a high-voltage lithium battery 13, a travel motor 8, a travel electronic control unit 9, a pump motor 11, a pump electronic control unit 12, a hydraulic oil tank 4, a central controller 15, a temperature sensor group 7, a dual-chamber cooling water tank 1 (first chamber 1-1, second chamber 1-2, and water tank cooling fan 1-3), a battery-side water cooling circuit 16, a motor-electronic control-side water cooling circuit 10, a battery-side water pump 3, a motor-electronic control-side water pump 17, a hydraulic oil active cooling fan 5, and a charging port 14, etc., with the specific structure as follows (e.g. Figure 2 (as shown) The counterweight 2 and the frame 6 are core structural components used to mount and secure other parts. The counterweight 2 is a one-piece cast structure with a central heat dissipation channel, and a protective mesh surrounds the channel. Figure 3 As shown, the frame 6 consists of four parts: a front frame 6-1, an upper intermediate frame 6-21, a lower intermediate frame 6-22, and a rear frame 6-3. The front frame 6-1 is used to mount the travel motor 8 and the travel electronic control unit 9; the rear frame 6-3 is used to mount components such as the dual-chamber radiator 1, the battery-side water pump 3, and the motor-controlled side water pump 17. The upper intermediate frame 6-21 is used to fix components such as the pump motor 11, the pump electronic control unit 12, the central controller 15, the hydraulic oil tank 4, the hydraulic oil active cooling fan 5, and the charging port 14. The upper intermediate frame 6-21 has no front baffle and can directly communicate with the outside; the rear baffle has a square hole in the middle, which, together with the dual-chamber radiator 1 mounted on the rear frame 6-3 and the cooling channel between the counterweight 2, forms a complete air duct. Multiple rectangular holes are opened near the hydraulic oil tank 4 on the rear baffle for passive cooling of the hydraulic oil tank 4. The lower intermediate frame 6-22 is the battery compartment, used to mount and fix the high-voltage lithium battery 13.

[0035] The high-voltage lithium battery 13 consists of a heating module with built-in heating, which is electrically connected to the central controller 15. When charging under low-temperature conditions, it can heat the battery to keep the temperature of the high-voltage lithium battery 13 within the ideal fast-charging temperature range.

[0036] The hydraulic oil tank 4 is welded from steel plates and is located on the middle frame of the chassis 6, near the rear panel, at a position with multiple rectangular holes, which can create air convection when the forklift is moving.

[0037] The central controller 15 adopts a vehicle control unit (VCU) or a programmable logic controller (PLC) and has a multi-channel analog input interface, which can receive the standard signals output by the temperature sensor group 7. The central controller 15 has a built-in control algorithm that can automatically adjust the operating parameters of the battery-side water pump 3, the motor-controlled water pump 17, and the water tank cooling fans 1-3 according to the temperature deviation, so as to achieve precise temperature control.

[0038] The temperature sensor group 7 includes temperature sensors respectively installed on the high-voltage lithium battery 13, the walking motor 8, the walking electronic control 9, the pump motor 11, the pump electronic control 12 and the hydraulic oil tank 4. Each temperature sensor is electrically connected to the central controller 15 and is used to transmit the collected temperature signal to the central controller 15.

[0039] like Figure 4 As shown, the dual-chamber cooling water tank 1 adopts an integrated independent sealed structure. The two chambers share a single cooling fan 1-3, and the forced convection of the cooling fan 1-3 achieves simultaneous heat dissipation for both chambers. The dual-chamber cooling water tank 1 is made of aluminum alloy, which has the characteristics of corrosion resistance and good thermal conductivity. The first chamber 1-1 and the second chamber 1-2 are separated by a sealed partition to avoid heat dissipation interference caused by coolant mixing. The cooling fan 1-3 is a variable frequency fan, and the air volume can be dynamically adjusted by the central controller 15 according to temperature changes. The first chamber 1-1 of the dual-chamber cooling water tank 1 is connected to the battery-side water cooling circuit 16 to dissipate heat from the high-voltage lithium battery 13; the second chamber 1-2 of the dual-chamber cooling water tank 1 is connected to the motor control-side water cooling circuit 10. The walking motor 8, walking control 9, pump motor 11, and pump control 12 are connected in series in the motor control-side water cooling circuit 10 to achieve overall heat dissipation.

[0040] The battery-side water cooling circuit 16 and the motor control-side water cooling circuit 10 are respectively equipped with an independent battery-side water pump 3 and a motor control-side water pump 17 that support speed adjustment, and both are electrically connected to the central controller 15 and are independently controlled by the central controller 15.

[0041] The hydraulic oil active cooling fan 5 can be started or stopped via a switch. It is located on the air cooling channel of the hydraulic oil tank 4, which is situated on the middle frame of the forklift 6 at a position with multiple rectangular holes near the rear panel. This allows for air convection when the forklift is in motion. The hydraulic oil active cooling fan 5 is electrically connected to the central controller 15, which controls its start and stop based on the hydraulic oil temperature.

[0042] The high-voltage lithium battery forklift temperature adaptive control method provided by this invention, such as... Figure 1 The steps shown are as follows: Step 1: Temperature signal acquisition and transmission. Temperature sensors are installed on the high-voltage lithium battery 13, travel motor 8, travel electronic control 9, pump motor 11, pump electronic control 12 and hydraulic oil tank 4 of the forklift. Each temperature sensor acquires the temperature signal of the corresponding component in real time and transmits the temperature signal to the central controller 15.

[0043] Step 2: Temperature definition and signal processing. The central controller 15 receives the temperature signals transmitted by each temperature sensor, defines the temperature of the high-voltage lithium battery 13 as T0, the combined temperature of the walking motor 8, walking electronic control 9, pump motor 11, and pump electronic control 12 as T1, and the hydraulic oil temperature as T2.

[0044] Step 3: Setting preset temperature thresholds. The central controller 15 has built-in preset temperature thresholds A_discharge, A_charge1, A_charge2, B, and C. Among them, A_discharge is the threshold for enhancing heat dissipation during high-voltage lithium battery 13 discharge; A_charge1 is the threshold for starting preheating during charging of high-voltage lithium battery 13; A_charge2 is the threshold for stopping preheating during charging of high-voltage lithium battery 13; A_charge3 is the threshold for enhancing heat dissipation during charging of high-voltage lithium battery 13; B is the threshold for enhancing heat dissipation in the water-cooling circuit 10 on the motor control side; and C is the threshold for starting the hydraulic oil active cooling fan 5. The thresholds satisfy the following hierarchical relationship: When the vehicle is in operation, A < B < C; When the vehicle is charging, Acharge1 < Acharge2 < Acharge3.

[0045] Step 4: Execution of hierarchical control logic. The central controller 15 compares the collected T0, T1, and T2 values ​​with their corresponding preset thresholds, and outputs control commands to each heat dissipation actuator based on the comparison results. The specific control logic is as follows: First, the central controller 15 collects the connection signal of the charging port 14 and the status of the vehicle key switch in real time, and makes a comprehensive judgment on the current vehicle operating condition: if the charging port 14 is detected to be physically connected and the charging communication signal is normal, and the vehicle key switch is in the off position, it is determined to be in charging condition; otherwise, it is determined to be in operating condition.

[0046] When the forklift is in operation, the central controller 15 performs temperature control according to the following logic: Battery temperature control logic: The temperature sensor monitors the temperature T0 of the high-voltage lithium battery 13 in real time. When T0 ≥ A discharge, the central controller 15 outputs a control signal to the battery-side water pump 3 and the water tank cooling fan 1-3 of the battery-side water cooling circuit 16. Based on the temperature deviation, the PID algorithm is used to calculate the control quantity and adjust the speed of the battery-side water pump 3 and the duty cycle of the water tank cooling fan 1-3. The control objective is to stabilize the temperature of the high-voltage lithium battery 13 within a suitable range to ensure optimal battery performance.

[0047] Motor and electronic control temperature control logic: Temperature sensors monitor the temperatures of the travel motor 8, travel electronic control unit 9, pump motor 11, and pump electronic control unit 12 respectively. The central controller 15 calculates the comprehensive temperature T1 (the average of the four temperatures). When T1 ≥ B, the central controller 15 outputs control signals to the motor electronic control side water pump 17 and water tank cooling fans 1-3 in the water cooling circuit 10 on the motor electronic control side. Based on the temperature deviation, a PID algorithm is used to calculate the control quantity and adjust the speed of the motor electronic control side water pump 17 and the duty cycle of the water tank cooling fans 1-3. The control objective is to stabilize the temperatures of the travel motor 8, travel electronic control unit 9, pump motor 11, and pump electronic control unit 12 within a suitable range to ensure optimal forklift operation performance.

[0048] Hydraulic oil temperature control logic: The temperature sensor monitors the hydraulic oil temperature T2. When T2 ≥ C, the central controller 15 outputs a switch signal to start the hydraulic oil active cooling fan 5, which continues to run. The hydraulic oil tank 4 is located on the middle frame 6 of the chassis 6, near the rear panel at a position with multiple rectangular holes. When the forklift is moving, air convection is formed. The activation of the hydraulic oil active cooling fan 5 can be superimposed with natural convection, significantly improving the heat dissipation effect.

[0049] When the forklift is in charging mode, the central controller 5 performs temperature control according to the following logic: Preheating control before charging: The temperature sensor monitors the temperature T0 of the high-voltage lithium battery 13. When T0 < A-charge 1, the central controller 15 outputs a switch signal to the heating module of the high-voltage lithium battery 13. The heating module starts and uses the battery's own residual power to preheat the battery. When the temperature T0 of the high-voltage lithium battery 13 is ≥ A-charge 2, the central controller 15 outputs a switch signal to the heating module of the high-voltage lithium battery 13. The heating module is turned off and the normal charging process begins.

[0050] Temperature control during charging: During charging, the central controller 15 monitors the temperature T0 of the high-voltage lithium battery 13 in real time. When T0 ≥ A-charge 3, the central controller 15 outputs a control signal to the battery-side water pump 3 and the water tank cooling fan 1-3 of the battery-side water cooling circuit 16. Based on the temperature deviation, the PID algorithm is used to calculate the control quantity and adjust the speed of the battery-side water pump 3 and the duty cycle of the water tank cooling fan 1-3 to stabilize the temperature of the high-voltage lithium battery 13 within a suitable range.

[0051] Step 5: Closed-loop control and dynamic adjustment. The central controller 15 receives temperature signals from each temperature sensor in real time and dynamically adjusts the operating parameters of each heat dissipation actuator to form closed-loop control and achieve adaptive balance of temperature of multiple components.

[0052] Compared with the prior art, the main technical innovations of this invention include: Multi-component temperature collaborative sensing and hierarchical control: By arranging temperature sensors on components such as the high-voltage lithium battery 13, the travel motor 8, the travel electronic control 9, the pump motor 11, the pump electronic control 12, and the hydraulic oil tank 4, comprehensive sensing of the overall machine's thermal state is achieved. A hierarchical control strategy is adopted, prioritizing battery temperature control according to the following relationship: when the vehicle is in operation, Adischarge < B < C; when the vehicle is charging, Acharge1 < Acharge2 < Acharge3. This ensures the highest priority for battery temperature control, guaranteeing temperature stability during charging and discharging, effectively improving battery lifespan, reducing total lifespan costs, and shortening the operating cycle.

[0053] Dual-chamber independent water cooling design: Utilizing a dual-chamber cooling tank 1, the battery-side water cooling circuit 16 and the motor / controller-side water cooling circuit 10 are independent of each other, avoiding the heat dissipation interference problem caused by the shared circuit between the battery and motor / controller in traditional solutions. Both chambers share a single fan, simplifying the structural design and saving space while ensuring effective heat dissipation.

[0054] Hydraulic oil active + passive composite air cooling: The hydraulic oil tank 4 is located on the middle frame 6 of the forklift, near the rear panel, at position 6-21 with multiple rectangular holes, creating air convection when the forklift is in motion. When the oil temperature rises, the hydraulic oil active cooling fan 5 starts, combining with natural convection to form composite air cooling, which can significantly improve heat dissipation efficiency. This design ensures effective heat dissipation while reducing energy consumption.

[0055] Adaptive closed-loop control strategy: Employing temperature feedback-based closed-loop control, the central controller 15 dynamically adjusts the operating parameters of each heat dissipation actuator according to real-time temperature changes. Precise temperature regulation is achieved through a PID control algorithm, avoiding the response lag problem of traditional fixed threshold control.

[0056] This invention, through technological innovation, effectively solves the technical problems existing in the thermal management systems of current high-pressure lithium-ion battery forklifts, providing reliable technical support for the application of high-pressure lithium-ion battery forklifts in heavy-duty and other high-intensity work scenarios. This technical solution features a simple structure, precise control, low energy consumption, and high reliability, and has promising prospects for widespread application.

[0057] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change. Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other. In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for adaptive temperature control of a high-voltage lithium-ion battery-powered forklift, characterized in that, Includes the following steps: Temperature acquisition steps: Temperature sensors are placed on the high-voltage lithium battery, walking motor, walking electronic control, pump motor, pump electronic control, and hydraulic oil tank respectively to collect the temperature of each component in real time and transmit it to the central controller. Signal processing steps: The central controller defines the high-voltage lithium battery temperature as T0, the average temperature of the walking motor, walking electronic control, pump motor, and pump electronic control as the comprehensive temperature T1, and the hydraulic oil temperature as T2. Threshold pre-configuration steps: The central controller pre-stores multiple sets of temperature thresholds. The threshold hierarchy for operating conditions satisfies A discharge < B < C, and the threshold hierarchy for charging conditions satisfies A charge 1 < A charge 2 < A charge 3. Among them, A discharge is the battery discharge heat dissipation enhancement threshold, B is the motor and electronic control heat dissipation enhancement threshold, C is the hydraulic fan start threshold, A charge 1 is the charging preheating start threshold, A charge 2 is the charging preheating stop threshold, and A charge 3 is the charging heat dissipation enhancement threshold. Operating condition graded temperature control steps: The central controller distinguishes between operating conditions and charging conditions based on the charging port connection communication signal and the key switch status, and executes the corresponding temperature control logic accordingly; Closed-loop dynamic adjustment steps: The central controller continuously receives temperature feedback and dynamically adjusts the operating parameters of each heat dissipation actuator to achieve adaptive temperature balance of multiple components.

2. The high-voltage lithium battery forklift temperature adaptive control method according to claim 1, characterized in that, The operating condition graded temperature control step includes operating condition temperature control logic. When T0≥A, the central controller uses a PID algorithm to adjust the speed of the battery-side water pump and the duty cycle of the variable frequency fan in the dual-chamber cooling water tank to cool the high-voltage lithium battery. When T1≥B, the central controller uses the PID algorithm to adjust the speed of the water pump on the motor control side and the duty cycle of the variable frequency fan in the dual-chamber cooling water tank to cool the motor control components. When T2≥C, the central controller outputs a switch signal to start the hydraulic oil active cooling fan, which works in conjunction with the frame air duct for natural convection cooling.

3. The high-voltage lithium battery forklift temperature adaptive control method according to claim 1, characterized in that, The graded temperature control step for operating conditions includes charging operating condition temperature control logic: When T0 < A charging 1, the built-in heating module of the high-voltage lithium battery is activated for preheating; when T0 ≥ A charging 2, the heating module is turned off and normal charging begins. During the charging process, when T0≥A3, the PID algorithm is used to adjust the battery-side water pump and the water tank cooling fan to suppress the battery charging temperature rise.

4. The high-voltage lithium battery forklift temperature adaptive control method according to claim 1, characterized in that, The high-voltage lithium battery is equipped with a separate water-cooling circuit on the battery side. The walking motor, walking electronic control, pump motor, and pump electronic control are connected in series in the water-cooling circuit on the motor electronic control side. The two water-cooling circuits are isolated from each other and have independent flow control.

5. The high-voltage lithium battery forklift temperature adaptive control method according to claim 1, characterized in that, It adopts an integrated dual-chamber cooling water tank, with an internal sealed partition separating the first and second chambers that are not connected to each other; the first chamber is connected to the water cooling circuit on the battery side, and the second chamber is connected to the water cooling circuit on the motor control side. The two chambers share the same variable frequency water tank cooling fan for synchronous heat dissipation.

6. The high-voltage lithium battery forklift temperature adaptive control method according to claim 1, characterized in that, The hydraulic oil tank is located on the middle frame of the vehicle frame near the rear baffle; the rear baffle has a rectangular through hole for hydraulic cooling, and a through cooling channel is provided in the middle of the counterweight, which is connected to the dual-chamber radiator to form an integrated cooling air duct for the whole vehicle.

7. The high-voltage lithium battery forklift temperature adaptive control method according to claim 1, characterized in that, The high-voltage lithium battery integrates a self-powered heating module, which is independently controlled by the central controller and only starts preheating in the low-temperature range during charging.

8. A high-voltage lithium-ion battery forklift, characterized in that, The high-voltage lithium battery forklift temperature adaptive control method described in any one of claims 1-7 is used for vehicle thermal management, including: frame, counterweight, high-voltage lithium battery, hydraulic oil tank, central controller, temperature sensor group, dual-chamber heat sink, battery-side water cooling circuit, motor-controller-side water cooling circuit, battery-side water pump, motor-controller-side water pump, hydraulic oil active cooling fan and charging port. The vehicle frame is divided into a front frame, an upper middle frame, a lower middle frame, and a rear frame. The front frame is used to install the travel motor and travel electronic control. The rear frame is used to assemble a dual-chamber cooling water tank, a battery-side water pump, and a motor-controlled side water pump. The upper middle frame is used to fix the pump motor, pump electronic control, central controller, hydraulic oil tank, hydraulic oil active cooling fan, and charging port. The lower middle frame has a battery compartment, in which a high-voltage lithium battery is installed. The counterweight is a one-piece cast structure with a through heat dissipation channel in the middle and a protective net on the outside of the heat dissipation channel. The rear panel of the frame has a square ventilation hole in the middle and a rectangular hydraulic cooling hole on the side. The counterweight heat dissipation channel, the rear panel ventilation hole and the dual-chamber radiator are connected to form a complete heat dissipation air duct for the whole vehicle.

9. A high-voltage lithium battery forklift according to claim 8, characterized in that, The dual-chamber cooling water tank is an integrated aluminum alloy structure, with a sealed partition inside separating a first chamber and a second chamber that are not interconnected. The water tank is equipped with a shared variable frequency cooling fan. The first chamber is connected to the battery-side water cooling circuit, and the second chamber is connected to the motor control-side water cooling circuit. The travel motor, travel control, pump motor, and pump control are connected in series to the motor control-side water cooling circuit. The battery-side water cooling circuit and the motor control-side water cooling circuit are respectively equipped with variable frequency speed-regulating battery-side water pumps and motor control-side water pumps, and both water pumps are electrically connected to the central controller.

10. A high-voltage lithium-ion battery forklift according to claim 8, characterized in that, The temperature sensor array is respectively mounted on the high-voltage lithium battery, the travel motor, the travel electronic control unit, the pump motor, the pump electronic control unit, and the hydraulic oil tank. All temperature sensor signal output terminals are connected to the central controller. The hydraulic oil active cooling fan is located in the air-cooling channel of the hydraulic oil tank and is controlled by the central controller to start and stop. The high-voltage lithium battery integrates a built-in heating module, which is controlled by the central controller. The central controller is a VCU vehicle controller or a PLC programmable logic controller, with built-in PID temperature control algorithm, working condition judgment logic, and graded temperature thresholds. It is used to receive temperature signals and independently control the operation of each water pump, water tank cooling fan, hydraulic oil active cooling fan, and battery heating module.

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