Self-circulation electric vehicle battery liquid cooling heat dissipation device and heat dissipation method

Abstract

The invention discloses a self-circulation electric automobile battery liquid cooling heat dissipation device and a heat dissipation method.The self-circulation electric automobile battery liquid cooling heat dissipation device comprises a shell, fan blades, a motor generator, an electromagnetic clutch, a water pump, a liquid cooling plate and an energy storage battery, and the shell is fixed to the bottom of an automobile battery pack and serves as a battery bottom protection plate; the fan blades are rotationally connected to the shell and fixed to a motor shaft of the motor generator, the fan blades rotate to convert wind energy into mechanical energy, and the energy storage battery is connected with the motor generator and stores electric energy generated by the motor generator. The two connecting ends of the electromagnetic clutch are connected with the motor generator and the water pump correspondingly, the electromagnetic clutch attracts and enables the motor generator to be linked with the water pump to rotate, and the water pump is started to achieve circulation of cooling liquid in the liquid cooling plate.

Description

Technical Field

[0001] This invention relates to a self-circulating liquid cooling heat dissipation device and method for electric vehicle batteries. Background Technology

[0002] With the increasing popularity of electric vehicles, thermal management of power batteries has become crucial to ensuring their performance, safety, and lifespan. Batteries generate a large amount of heat during charging and discharging. If this heat cannot be dissipated in time, it can lead to excessively high battery temperatures, resulting in performance degradation, shortened lifespan, and even safety incidents such as thermal runaway.

[0003] Currently, the mainstream battery cooling solutions mainly include air cooling and liquid cooling. Air cooling systems are simple in structure and low in cost, but they have low heat dissipation efficiency and poor temperature uniformity, making it difficult to meet the heat dissipation requirements of high-energy-density battery packs. Therefore, liquid cooling systems have become a standard feature in mid-to-high-end electric vehicles.

[0004] Existing liquid cooling systems are mainly powered in two ways: one is by drawing power directly from the vehicle's high-voltage battery to drive an independent motor that powers the water pump; the other is by indirectly powering the water pump through the engine (in hybrid vehicles) or a mechanical transmission link via the drive motor. However, both of these methods face challenges in practical applications, such as energy efficiency and adaptability to operating conditions, making it difficult to meet the needs of new energy vehicles for low energy consumption and all-scenario thermal management.

[0005] The electric water pump and its control system consume energy from the power battery, which directly affects the vehicle's driving range and contradicts the energy-saving design goals of electric vehicles. Furthermore, the system's heat dissipation capacity is highly dependent on the precise judgment of the control unit. Electric vehicles may experience response delays or control failures during DC fast charging, aggressive driving, high-speed travel, or in high-temperature environments, potentially leading to complete failure of the battery cooling system and posing a safety hazard. Summary of the Invention

[0006] This invention provides a self-circulating liquid cooling device and method for electric vehicle batteries to address the problems existing in the prior art. This invention utilizes the natural wind generated during vehicle operation as power to drive the coolant circulation, achieving highly efficient heat dissipation with zero additional energy consumption. Furthermore, as an independent module, it is not affected by the vehicle itself and possesses advantages such as simple structure, high reliability, and strong self-adaptability.

[0007] The technical solutions adopted in this invention are as follows:

[0008] A self-circulating liquid cooling device for electric vehicle batteries includes a housing, fan blades, an electric generator, an electromagnetic clutch, a water pump, a liquid cooling plate, and an energy storage battery. The housing is fixed to the bottom of the vehicle battery pack and serves as a battery bottom protection plate. The fan blades are rotatably connected to the housing and fixed to the motor shaft of the electric generator. The rotation of the fan blades converts wind energy into mechanical energy. The energy storage battery is connected to the electric generator and stores the electrical energy generated by the electric generator. The two connecting ends of the electromagnetic clutch are respectively connected to the electric generator and the water pump. When the electromagnetic clutch is engaged, it causes the electric generator to drive the water pump to rotate. The water pump starts to circulate the coolant in the liquid cooling plate.

[0009] Furthermore, it also includes a temperature sensor and a controller. The temperature sensor is used to detect the battery pack temperature in real time and transmit the temperature signal to the controller. The controller controls the engagement or disengagement of the electromagnetic clutch to control the operation of the water pump.

[0010] Furthermore, the fan blades are provided with at least three, and all the fan blades are linked together by a toothed pulley and a gear. The motor shaft of the electric generator is fixed to one of the fan blades through a rotating shaft.

[0011] Furthermore, the housing is provided with several air inlets and one air outlet, and a fan blade is rotatably connected in each air inlet. The electric generator, electromagnetic clutch, water pump, liquid cooling plate and energy storage battery are all located inside the housing, and the liquid cooling plate is in contact with the battery pack.

[0012] Furthermore, the housing is also provided with heat dissipation fins that are connected to the liquid cooling plate. The convective gas that enters the housing through the air inlet and flows out through the air outlet cools the heat dissipation fins and the liquid cooling plate.

[0013] Furthermore, the air inlet is connected to the air intake grille via a flexible hose.

[0014] The present invention also discloses a heat dissipation method, comprising:

[0015] a) During vehicle operation, the oncoming wind is introduced into the air intake through the air intake grille, driving the fan blades to rotate and converting wind energy into mechanical energy. The electric generator generates electricity, and the energy storage battery stores the electrical energy generated by the electric generator.

[0016] b) The battery pack temperature is collected in real time by a temperature sensor, and the temperature signal is sent to the controller;

[0017] c) The controller compares the collected temperature with a preset threshold and performs the following tiered control:

[0018] If the temperature is higher than the first threshold T1, the controller issues a energizing command to engage the electromagnetic clutch, and the electric generator drives the water pump, so that the coolant circulates and dissipates heat under the action of the water pump.

[0019] If the temperature is lower than the second threshold T2, the controller issues a disconnect command to disengage the electromagnetic clutch. The fan blades then drive the electric generator only to store wind energy. All the electrical energy output by the electric generator is stored in the energy storage battery for subsequent static heat dissipation.

[0020] d) When the vehicle is statically charging and the battery pack temperature is higher than the first threshold T1, the controller calls the energy storage battery to supply power to the electric generator and re-engages the electromagnetic clutch. The electric generator drives the water pump, and the coolant circulates and dissipates heat under the action of the water pump until the temperature drops below the second threshold T2. The controller then controls the magnetic clutch to disengage and cuts off the electric generator, ending the heat dissipation process.

[0021] Furthermore, in step c), the difference ΔT = T1 - T2 between the first threshold T1 and the second threshold T2 is set to 3 ℃ to 8 ℃ to prevent the electromagnetic clutch from frequently engaging / disengaging.

[0022] Furthermore, in step c), the controller monitors the speed of the electric generator in real time. When the vehicle speed is below 20 km / h and the speed of the electric generator is insufficient to maintain the minimum flow rate of coolant, it automatically switches to the water pump driven by the energy storage battery.

[0023] The present invention has the following beneficial effects:

[0024] This invention relies entirely on the oncoming wind generated by vehicle movement as its core power source. Fan blades convert wind energy into mechanical energy to drive the cooling system, without consuming any electrical energy from the vehicle's battery. This fundamentally solves the problem of traditional liquid cooling systems depending on the battery and thus limiting driving range. Furthermore, when the vehicle is moving and the battery does not require cooling, the device can convert excess wind energy into electrical energy and store it in an energy storage battery, achieving energy recovery and reuse, further improving the energy efficiency of electric vehicles. Through hierarchical control using temperature sensors and a controller, combined with flexible switching of the electromagnetic clutch, the device achieves intelligent adaptation to four operating conditions: "cooling during driving, energy storage during driving, cooling during static charging, and cooling during low-speed charging." Cooling capacity is positively correlated with vehicle speed. During high-speed driving and peak battery heat generation, sufficient wind power leads to increased cooling efficiency. At low speeds or when stationary, the energy storage battery can supplement cooling needs, avoiding the risks of response delays or failures associated with traditional systems that rely on complex control logic. Simultaneously, a temperature threshold difference design of 3℃~8℃ effectively prevents frequent electromagnetic clutch operation, extending component lifespan and reducing the probability of failure. Attached Figure Description

[0025] Figure 1 This is a structural diagram of the present invention.

[0026] Figure 2 This is a structural diagram of the present invention. Detailed Implementation

[0027] The invention will now be further described with reference to the accompanying drawings.

[0028] The following is combined Figure 1 and Figure 2 The present invention provides a detailed description of the specific implementation of a self-circulating liquid cooling heat dissipation device and heat dissipation method for electric vehicle batteries.

[0029] I. Specific configuration of the device structure.

[0030] In this embodiment, the model, installation method, and connection relationship of each core component of the self-circulating electric vehicle battery liquid cooling heat dissipation device are as follows:

[0031] Housing 1: It is made of 3mm thick 5052 aluminum alloy sheet by one-piece stamping, with overall dimensions of 1200mm×800mm×80mm (length×width×height). It is fixed to the car battery pack bottom through the reserved mounting holes by M8 stainless steel bolts. A 2mm thick thermal conductive silicone pad (thermal conductivity ≥3.5W / (m·K)) is pasted on the upper surface of the housing to achieve a tight fit between the housing and the battery pack and to buffer vibration during driving.

[0032] Three circular air inlets 11 with a diameter of 80mm are evenly distributed at the front end of the housing, and a rectangular air outlet 12 with a size of 150mm×100mm is opened in the middle of the rear end of the housing. Each air inlet 11 is connected to the reserved interface of the front air intake grille of the car through a 500mm long heat-resistant EPDM hose. The two ends of the hose are fastened with hose clamps to ensure stable intake of the oncoming air.

[0033] Fan blade 2 and linkage mechanism: A total of 3 fan blades are provided, each fan blade is rotatably connected to the corresponding air inlet 11 through a deep groove ball bearing. The ends of the shafts of the 3 fan blades are all fixed with spur gears, and the gears of adjacent fan blades are meshed and linked through a toothed belt pulley to ensure that the 3 fan blades rotate synchronously; the shaft of the middle fan blade is fixedly connected to the motor shaft of the electric generator 3 through a coupling, so that the rotation of the fan blades provides power input to the electric generator.

[0034] Electric generator 3 and energy storage battery 7: Both electric generator 3 and energy storage battery 7 are fixed inside the housing 1. The energy storage battery 7 is connected to electric generator 3 through wires, and a 10A fuse and a charging management module (model TP4056) are connected in series on the wires to achieve stable energy storage and overcharge protection.

[0035] Electromagnetic clutch 4 and water pump 5: The driving end of the electromagnetic clutch is connected to the output shaft of the electric generator 3 via a pulley, and the driven end is connected to the input shaft of the water pump 5 via a coupling; the water pump is a miniature centrifugal coolant pump, fixed inside the housing 1. The water inlet of the water pump is connected to the outlet of the liquid cooling plate 6 via a heat-resistant silicone tube, and the water outlet of the water pump is connected to the inlet of the liquid cooling plate 6 via a silicone tube of the same specification, forming a coolant circulation loop; the loop is filled with ethylene glycol-water coolant (volume ratio 50:50, freezing point -35℃, boiling point 108℃).

[0036] Liquid cooling plate 6 and heat dissipation fins 8: The liquid cooling plate is an aluminum alloy microchannel liquid cooling plate, which is attached to the bottom of the battery pack under the thermally conductive silicone pad; the heat dissipation fins 8 are located on the outside of the liquid cooling plate 6, and the coolant in the liquid cooling plate 6 is dissipated through the heat dissipation fins 8.

[0037] Temperature sensor and controller: Three NTC thermistor sensors are used for temperature measurement and are connected to the controller via shielded wires. The controller is an STM32F103 series MCU chip, which is fixed inside the housing 1 near the energy storage battery 7. It is connected to the temperature sensor, electromagnetic clutch 4, electric generator 3, energy storage battery 7 and axial auxiliary fan via wires to realize signal acquisition and command output.

[0038] II. Specific execution process of heat dissipation method.

[0039] In this embodiment, the preset temperature thresholds are: first threshold T1 = 35℃, second threshold T2 = 30℃, and temperature difference ΔT = 5℃ (within a reasonable range of 3℃~8℃ to avoid frequent operation of the electromagnetic clutch); the electric generator 3 maintains a minimum coolant flow rate (3L / min) at a minimum speed of 1000rpm, corresponding to a vehicle speed of approximately 20km / h; the specific heat dissipation process is divided into the following three operating conditions:

[0040] Operating Condition 1: Vehicle is in motion (speed ≥ 20 km / h) and battery pack temperature > T1 (35℃).

[0041] When the vehicle is in motion, the oncoming wind enters the heat-resistant EPDM hose through the air intake grille, and then enters the three air inlets 11 of the housing 1, driving the three fan blades 2 to rotate synchronously (because the fan blades are linked to the gears through the toothed belt pulley, the rotation speed is consistent, about 1500~3000rpm, which increases with the vehicle speed).

[0042] The fan blade 2 drives the motor shaft of the electric generator 3 to rotate, and the electric generator enters the power generation mode, outputting 12V DC power. The electrical energy is stored in the energy storage battery 7 through the charging management module.

[0043] The temperature sensor collects the battery pack temperature in real time (e.g., the detected temperature is 38℃) and transmits the signal to the controller; the controller compares the temperature with T1 (35℃) and sends an engagement command to the electromagnetic clutch 4.

[0044] When the electromagnetic clutch 4 engages, the power of the electric generator 3 is transmitted to the water pump 5 through the clutch, driving the water pump to operate and causing the coolant to circulate in the internal channel of the liquid cooling plate 6 (flow rate 6~10L / min, which increases with the fan blade speed).

[0045] When the coolant flows within the liquid cooling plate 6, it absorbs the heat generated by the battery pack, causing its temperature to rise. Subsequently, the high-temperature coolant flows through the heat dissipation fins 8. At this time, the convective gas introduced by the air inlet 11 (flow velocity 5~15m / s, which increases with vehicle speed) passes through the gaps between the heat dissipation fins and exchanges heat with the fins and the liquid cooling plate, carrying away the heat of the coolant. The cooled coolant returns to the water pump 5 to complete the circulation, and the high-temperature gas after heat exchange is discharged through the air outlet 12 at the rear end of the housing 1.

[0046] Once the temperature sensor detects that the battery pack temperature has dropped below T2 (30°C), the controller issues a disconnect command, the electromagnetic clutch 4 disengages, the water pump 5 stops running, and the system switches to energy storage mode.

[0047] Operating Condition 2: Vehicle is in motion (speed ≥ 20 km / h) and battery pack temperature < T2 (30℃).

[0048] The oncoming wind drives the fan blades 2 to rotate, which in turn drives the electric generator 3 to generate electricity. The process of storing the electrical energy in the energy storage battery 7 is the same as in operating condition 1.

[0049] When the temperature sensor detects that the battery pack temperature (e.g., 28°C) is lower than T2 (30°C), the controller issues a disconnect command, and the electromagnetic clutch 4 remains disengaged.

[0050] The power of the electric generator 3 is only used for generating electricity and is not transmitted to the water pump 5. The water pump 5 does not operate and the coolant does not circulate. At this time, the device only performs wind energy recovery and storage to reserve electrical energy for subsequent static heat dissipation or low-speed heat dissipation. When the energy storage battery 7 reaches full charge (5Ah), the charging management module automatically cuts off the charging circuit to avoid overcharging.

[0051] Operating Condition 3: The vehicle is statically charging and the battery pack temperature is greater than T1 (35℃).

[0052] When the vehicle is stationary (such as when it is charging at a charging station), there is no oncoming wind to drive the fan blades 2, and the electric generator 3 cannot generate electricity using wind power.

[0053] During charging, the battery pack generates heat. The temperature sensor detects that the temperature has risen to 36℃ (>T1=35℃) and transmits the signal to the controller.

[0054] The controller issues commands: on the one hand, it calls upon the electrical energy of the energy storage battery 7 to power the electric generator 3, enabling the electric generator to enter motor mode (speed 1500 rpm); on the other hand, it controls the electromagnetic clutch 4 to engage.

[0055] After the electric generator 3 starts running, it drives the water pump 5 through the electromagnetic clutch 4, so that the coolant circulates in the liquid cooling plate 6 (flow rate 6L / min).

[0056] After the coolant absorbs the heat from the battery pack, it completes the circulation and heat dissipation. Until the temperature sensor detects that the battery pack temperature has dropped to 29℃ (<T2=30℃), the controller cuts off the power supply to the electric generator 3, controls the electromagnetic clutch 4 to disengage, and at the same time shuts off the axial auxiliary fan, the heat dissipation process ends.

[0057] Operating condition 4: Vehicle is in motion (speed < 20 km / h, such as 15 km / h) and battery pack temperature > T1 (35℃).

[0058] At low vehicle speeds, the fan blades 2 rotate at only 800 rpm (below the minimum coolant flow rate of 1000 rpm required by the electric generator), resulting in insufficient power output from the electric generator 3 (only 200W).

[0059] The temperature sensor detected a battery pack temperature of 37℃ (>T1=35℃). The controller simultaneously executed two commands: first, to control the electromagnetic clutch 4 to engage; and second, to call upon the electrical energy of the energy storage battery 7 to work in conjunction with the output electrical energy of the electric generator 3 to drive the electric generator 3 to operate at 1200 rpm.

[0060] With the assistance of the electric generator 3, the speed increases to over 1000 rpm, driving the water pump 5 via the electromagnetic clutch 4 to ensure that the coolant flow rate reaches the minimum requirement of 3L / min. When the vehicle speed increases to over 20km / h and the fan blade 2 speed reaches over 1000 rpm, and the power output of the electric generator 3 meets the water pump drive requirements, the controller automatically cuts off the power supply from the energy storage battery 7 and switches to pure wind power drive mode.

[0061] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A self-circulating liquid cooling heat dissipation device for electric vehicle batteries, characterized in that: The device includes a housing (1), a fan blade (2), an electric generator (3), an electromagnetic clutch (4), a water pump (5), a liquid cooling plate (6), and an energy storage battery (7). The housing (1) is fixed to the bottom of the car battery pack and serves as a battery bottom protection plate. The fan blade (2) is rotatably connected to the housing (1) and fixed to the motor shaft of the electric generator (3). The fan blade (2) rotates to convert wind energy into mechanical energy. The energy storage battery (7) is connected to the electric generator (3) and stores the electrical energy generated by the electric generator. The two connecting ends of the electromagnetic clutch (4) are respectively connected to the electric generator (3) and the water pump (5). When the electromagnetic clutch (4) is engaged, it causes the electric generator (3) to rotate in conjunction with the water pump (5). The water pump (5) starts to realize the circulation of coolant in the liquid cooling plate (6).

2. The self-circulating electric vehicle battery liquid cooling device as described in claim 1, characterized in that: It also includes a temperature sensor and a controller. The temperature sensor is used to detect the battery pack temperature in real time and transmit the temperature signal to the controller. The controller controls the engagement or disengagement of the electromagnetic clutch to control the operation of the water pump (5).

3. The self-circulating liquid cooling heat dissipation device for electric vehicle batteries as described in claim 1, characterized in that: The fan blades (2) are provided with at least three, and all the fan blades (2) are linked together by a toothed pulley and a gear. The motor shaft of the electric generator (3) is fixed to one of the fan blades (2) through a rotating shaft.

4. The self-circulating liquid cooling heat dissipation device for electric vehicle batteries as described in claim 3, characterized in that: The housing (1) is provided with several air inlets (11) and an air outlet (12). Each air inlet (11) is rotatably connected to a fan blade (2). The electric generator (3), electromagnetic clutch (4), water pump (5), liquid cooling plate (6) and energy storage battery (7) are all located inside the housing, and the liquid cooling plate (6) is in contact with the battery pack.

5. The self-circulating electric vehicle battery liquid cooling device as described in claim 4, characterized in that: The housing (1) is also provided with heat dissipation fins (8) that are connected to the liquid cooling plate (6). The convective gas that enters the housing through the air inlet and flows out through the air outlet cools the heat dissipation fins (8) and the liquid cooling plate (6).

6. The self-circulating electric vehicle battery liquid cooling device as described in claim 4, characterized in that: The air inlet (11) is connected to the air intake grille via a hose.

7. A heat dissipation method for a self-circulating liquid cooling heat dissipation device for electric vehicle batteries as described in any one of claims 1-6, characterized in that: a) During vehicle operation, the oncoming wind is introduced into the air intake (11) through the air intake grille, driving the fan blades (2) to rotate, converting wind energy into mechanical energy, generating electricity through the electric generator (3), and storing the electrical energy generated by the electric generator through the energy storage battery (7). b) The battery pack temperature is collected in real time by a temperature sensor, and the temperature signal is sent to the controller; c) The controller compares the collected temperature with a preset threshold and performs the following tiered control: If the temperature is higher than the first threshold T1, the controller issues a energizing command to engage the electromagnetic clutch, and the electric generator (3) drives the water pump (5), and the coolant circulates and dissipates heat under the action of the water pump (5). If the temperature is lower than the second threshold T2, the controller issues a disconnect command to disengage the electromagnetic clutch. The fan blade (2) drives the electric generator (3) to store wind energy. All the electrical energy output by the electric generator (3) is stored in the energy storage battery (7) for subsequent static heat dissipation. d) When the vehicle is statically charging and the battery pack temperature is higher than the first threshold T1, the controller calls the energy storage battery (7) to supply power to the electric generator (3) and causes the electromagnetic clutch to engage again. The electric generator (3) drives the water pump (5), and the coolant circulates and dissipates heat under the action of the water pump (5) until the temperature drops below the second threshold T2. The controller then controls the magnetic clutch to disengage and cuts off the electric generator (3) to end the heat dissipation.

8. The heat dissipation method of the self-circulating electric vehicle battery liquid cooling heat dissipation device as described in claim 7, characterized in that: In step c), the difference ΔT = T1 - T2 between the first threshold T1 and the second threshold T2 is set to 3 ℃ to 8 ℃.

9. The heat dissipation method of the self-circulating electric vehicle battery liquid cooling heat dissipation device as described in claim 7, characterized in that: In step c), the controller monitors the speed of the electric generator (3) in real time. When the vehicle speed is below 20 km / h and the speed of the electric generator (3) is insufficient to maintain the minimum flow rate of coolant, it automatically switches to the water pump driven by the energy storage battery (7) to supplement the power.

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