Battery thermal management system for electric tractor

Abstract

This application relates to a battery thermal management system for an electric tractor, characterized by comprising: an in-vehicle heater core, a four-way valve, a PTC (Power Transmitter Centralizer), an air conditioning water pump, a third three-way valve, a second heat exchanger, an expansion tank, a first heat exchanger, a compressor, a second three-way valve, an expansion valve, a battery pack, a condenser, a water pump, and a first three-way valve. The battery thermal management system for an electric tractor provided in this application achieves switching between heating and cooling modes of the battery pack by setting a branch in the cooling unit circuit, ensuring the battery operates within its optimal range; it uses a single PTC to simultaneously heat both the battery and the cab, improving system integration and reducing system costs; and it achieves waste heat recovery from the battery pack by incorporating a four-way valve in the air conditioning system, utilizing the battery pack's heat to heat the cab, thus reducing system energy loss.

Description

Technical Field

[0001] This application relates to the field of battery thermal management, and more particularly to a battery thermal management system for electric tractors. Background Technology

[0002] With the promotion of national environmental protection policies, the trend of electrification in agricultural machinery is becoming increasingly apparent. Compared with traditional fuel vehicles, batteries have the advantages of energy saving and environmental protection. However, batteries require a suitable temperature range to maintain optimal working efficiency and extend battery life. In particular, batteries cannot be charged when the temperature is below 0°C and need to be heated to above 0°C to charge.

[0003] Currently, the common heating methods for battery systems are film heating and PTC heating. However, these methods often have slow heating rates, affecting operating efficiency. Moreover, when using PTC heating, the battery thermal management system and the air conditioning system often use two PTCs to form two separate circuits, resulting in low system integration. In addition, the heat generated during battery operation is exchanged between the coolant and the refrigerant without waste heat recovery, leading to inefficient use of waste heat and energy waste in the system. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this application provides a battery thermal management system for electric tractors.

[0005] In a first aspect, this application provides a battery thermal management system for an electric tractor, characterized in that it comprises: an in-vehicle heater core, a four-way valve, a PTC, an air conditioning water pump, a third three-way valve, a second heat exchanger, an expansion tank, a first heat exchanger, a compressor, a second three-way valve, an expansion valve, a battery pack, a condenser, a water pump, and a first three-way valve, wherein the in-vehicle heater core is connected to the four-way valve and the third three-way valve respectively; the four-way valve is connected to the third three-way valve, the PTC, and the second heat exchanger respectively; the air conditioning water pump is connected to the PTC, the third three-way valve, and the second heat exchanger respectively; the second heat exchanger is connected to the expansion tank, the battery pack, and the first heat exchanger respectively; the water pump is connected to the battery pack and the first heat exchanger respectively; the compressor is connected to the first heat exchanger and the condenser respectively; the first three-way valve is connected to the condenser, the expansion valve, and the second three-way valve respectively; and the second three-way valve is connected to the first three-way valve, the expansion valve, and the first heat exchanger respectively.

[0006] Preferably, the four-way valve has an A port and a C port, wherein the A port and the C port are connected to each other, the A port is connected to the second heat exchanger, and the C port is connected to the vehicle interior heater core.

[0007] Preferably, the four-way valve has a B port and a D port, wherein the B port and the D port are connected to each other and are both connected to the A port and the C port, the B port is connected to the PTC, and the D port is connected to the third three-way valve.

[0008] Preferably, the first three-way valve includes: an A port, which is connected to the condenser.

[0009] Preferably, the first three-way valve includes a B port, which is connected to the A port and the second three-way valve respectively.

[0010] Preferably, the first three-way valve includes a C port, which is connected to the B port, the expansion valve, and the second three-way valve.

[0011] Preferably, the second three-way valve includes: an outlet A, which is connected to the expansion valve.

[0012] Preferably, the second three-way valve includes a B outlet, which is connected to both the A outlet and the B port in the first three-way valve.

[0013] Preferably, the second three-way valve includes an outlet C, which is connected to the outlet A and the first heat exchanger.

[0014] Preferably, the third three-way valve includes: port A, port B, and port C, which are interconnected. Port A is connected to the vehicle interior heater core, port B is connected to port D of the four-way valve, and port C is connected to the air conditioning water pump and the second heat exchanger.

[0015] The technical solutions provided in this application have the following advantages compared with the prior art:

[0016] The battery thermal management system for electric tractors provided in this application embodiment achieves switching between heating and cooling modes of the battery pack by setting a branch in the cooling unit circuit, so that the battery operates within the optimal range; it uses one PTC to heat both the battery and the cab simultaneously, improving system integration and reducing system cost; and it achieves waste heat recovery from the battery pack by setting a four-way valve in the air conditioning system, using the heat from the battery pack to heat the cab, thereby reducing system energy loss. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a battery thermal management system for an electric tractor, provided as an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Figure 1 This is a schematic diagram of a battery thermal management system for an electric tractor, provided as an embodiment of this application.

[0022] This application provides a battery thermal management system for an electric tractor, comprising: an in-vehicle heater core, a four-way valve, a PTC, an air conditioning water pump, a third three-way valve, a second heat exchanger, an expansion tank, a first heat exchanger, a compressor, a second three-way valve, an expansion valve, a battery pack, a condenser, a water pump, and a first three-way valve. The in-vehicle heater core is connected to the four-way valve and the third three-way valve. The four-way valve is connected to the third three-way valve, the PTC, and the second heat exchanger. The air conditioning water pump is connected to the PTC, the third three-way valve, and the second heat exchanger. The second heat exchanger is connected to the expansion tank, the battery pack, and the first heat exchanger. The water pump is connected to the battery pack and the first heat exchanger. The compressor is connected to the first heat exchanger and the condenser. The first three-way valve is connected to the condenser, the expansion valve, and the second three-way valve. The second three-way valve is connected to the first three-way valve, the expansion valve, and the first heat exchanger.

[0023] In this embodiment, the four-way valve has a port A, a port B, a port C, and a port D. Port A and port C are connected to each other. Port A is connected to the second heat exchanger. Port C is connected to the vehicle interior heater core. Port B and port D are connected to each other and are also connected to ports A and C. Port B is connected to the PTC. Port D is connected to the third three-way valve.

[0024] Specifically, ports A, B, C, and D are interconnected in pairs to form channels AB, AC, AD, BC, BD, and CD, respectively.

[0025] In this embodiment, the first three-way valve includes: an A port, a B port, and a C port. The A port is connected to the condenser, the B port is connected to both the A port and the second three-way valve, and the C port is connected to the B port, the expansion valve, and the second three-way valve.

[0026] Specifically, interfaces A, B, and C are interconnected in pairs to form channels AB, AC, and BC, respectively.

[0027] In this embodiment, the second three-way valve includes an outlet A, an outlet B, and an outlet C. The outlet A is connected to the expansion valve, the outlet B is connected to the outlet A and the B port of the first three-way valve, and the outlet C is connected to the outlet A and the first heat exchanger.

[0028] In this embodiment, the third three-way valve includes: port A, port B, and port C. Port A, port B, and port C are interconnected. Port A is connected to the vehicle interior heater core, port B is connected to port D of the four-way valve, and port C is connected to the air conditioning water pump and the second heat exchanger.

[0029] Specifically, ports A, B, and C are interconnected in pairs to form channels AB, AC, and BC, respectively.

[0030] Figure 1 This is a diagram of the battery thermal management system, which includes two modes: cooling and heating.

[0031] A single PTC can heat the cockpit and battery pack in the following operating modes:

[0032] (1) The battery pack requires heating, but the cockpit does not.

[0033] When the ambient temperature drops below 0°C and the battery pack needs to be heated before charging, the air conditioning water pump and PTC are turned on. The coolant heated by the PTC flows through the second heat exchanger (heat exchanger 2), where it exchanges heat with the coolant flowing through the battery pack. Then, it flows back to the PTC through the AB channel of the four-way valve for continued heating. This process is repeated until the battery pack temperature reaches the required level. During this process, the CD channel of the four-way valve and the third three-way valve (three-way valve 3) are closed.

[0034] (2) The battery pack does not require heating, but the cockpit does.

[0035] The preset heating temperature requirement for the cockpit is T1. The actual operating temperature of the battery pack is T_actual_battery_temperature. When T1 < T_actual_battery_temperature, the residual heat of the battery pack can be used to heat the cockpit. At this time, the air conditioning water pump is turned on, and the PTC does not need to be turned on. The coolant flowing from the interior heater core flows sequentially through the CB channel of the four-way valve, the air conditioning water pump, the PTC, the second heat exchanger, the AD channel of the four-way valve, and the BA channel of the third three-way valve to the interior heater core. The coolant exchanges heat with the coolant flowing through the battery pack in the second heat exchanger, and finally, the warm air is delivered to the cockpit by the fan.

[0036] When the cabin heating temperature requirement T1 > T battery, the battery pack heat cannot meet the cabin's needs, so the PTC is activated for heating. At this time, the coolant flowing out of the cabin heater core flows sequentially through the CB channel of the four-way valve, the air conditioning water pump, the PTC, the CA channel of the third three-way valve, and the cabin heater core, and the fan delivers warm air to the cabin.

[0037] (3) Both the battery pack and the cockpit need to be heated.

[0038] To maintain a suitable operating temperature for the battery pack in low-temperature environments, it needs to be heated. At this time, the BD channel of the four-way valve is closed, while the AB and BC channels are simultaneously open. Coolant flowing from the vehicle's heater core passes through the CB channel of the four-way valve—the air conditioning water pump—and is heated by the PTC. A portion of the heated coolant then enters the vehicle's heater core through the AC channel of the third three-way valve to heat the passenger compartment. The remaining heated coolant flows to the second heat exchanger, where it exchanges heat with the coolant flowing through the battery pack. The exchanged coolant then returns to the vehicle's heater core via the AD channel of the four-way valve—the BA channel of the third three-way valve. This process is repeated to heat the passenger compartment and the battery pack.

[0039] (4) Battery pack cooling circuit operating mode:

[0040] The battery cooling circuit includes a battery pack cooling circuit and a cooling unit circuit. The battery pack cooling circuit includes the battery pack, outlet temperature sensor T, expansion tank, first heat exchanger (heat exchanger 1), second heat exchanger, and water pump. The cooling unit circuit includes pressure sensor P1, pressure sensor P2, compressor, condenser, fan, first three-way valve (three-way valve 1), second three-way valve (three-way valve 2), expansion valve, and first heat exchanger. The preset optimal operating temperature range for battery discharge is X1-X2. When T>X2, the compressor and fan start working. The high-temperature, high-pressure refrigerant from the compressor passes sequentially through the condenser—the AC channel of the first three-way valve—the expansion valve—the AC channel of the second three-way valve, becoming low-temperature, low-pressure, and then enters the first heat exchanger to exchange heat with the battery pack coolant.

[0041] When T < X1, the compressor is started. At this time, the fan does not work. The high-temperature and high-pressure refrigerant from the compressor passes through the AB channel of the first three-way valve and the BC channel of the second three-way valve in sequence before entering the first heat exchanger. It exchanges heat with the battery pack coolant and transfers the heat of the refrigerant to the coolant in the battery pack circuit, so that the battery operates in the optimal temperature range.

[0042] The battery thermal management system for electric tractors provided in this application embodiment achieves switching between heating and cooling modes of the battery pack by setting a branch in the cooling unit circuit, so that the battery operates within the optimal range; it uses one PTC to heat both the battery and the cab simultaneously, improving system integration and reducing system cost; and it achieves waste heat recovery from the battery pack by setting a four-way valve in the air conditioning system, using the heat from the battery pack to heat the cab, thereby reducing system energy loss.

[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0044] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A battery thermal management system for an electric tractor, characterized in that, include: The vehicle interior heater core includes a four-way valve, a PTC (Power Transmission Control Unit), an air conditioning water pump, a third three-way valve, a second heat exchanger, an expansion tank, a first heat exchanger, a compressor, a second three-way valve, an expansion valve, a battery pack, a condenser, a water pump, and a first three-way valve. The vehicle interior heater core is connected to both the four-way valve and the third three-way valve. The four-way valve is connected to the third three-way valve, the PTC, and the second heat exchanger. The air conditioning water pump is connected to the PTC, the third three-way valve, and the second heat exchanger. The second heat exchanger is connected to the expansion tank, the battery pack, and the first heat exchanger. The water pump is connected to the battery pack and the first heat exchanger. The compressor is connected to both the first heat exchanger and the condenser. The first three-way valve is connected to the condenser, the expansion valve, and the second three-way valve. The second three-way valve is connected to the first three-way valve, the expansion valve, and the first heat exchanger. The four-way valve has ports A, B, C, and D. Ports A and C are connected to each other. Port A is connected to the second heat exchanger, and port C is connected to the vehicle interior heater core. Ports B and D are connected to each other and are also connected to ports A and C. Port B is connected to the PTC, and port D is connected to the third three-way valve.

2. The battery thermal management system for electric tractors according to claim 1, characterized in that, The first three-way valve includes: an A port, which is connected to the condenser.

3. The battery thermal management system for electric tractors according to claim 2, characterized in that, The first three-way valve includes a B port, which is connected to the A port and the second three-way valve respectively.

4. The battery thermal management system for electric tractors according to claim 3, characterized in that, The first three-way valve includes a C port, which is connected to the B port, the expansion valve, and the second three-way valve.

5. The battery thermal management system for electric tractors according to claim 1, characterized in that, The second three-way valve includes: an outlet A, which is connected to the expansion valve.

6. The battery thermal management system for electric tractors according to claim 5, characterized in that, The second three-way valve includes an outlet B, which is connected to both the outlet A and the B port in the first three-way valve.

7. The battery thermal management system for electric tractors according to claim 6, characterized in that, The second three-way valve includes an outlet C, which is connected to both the outlet A and the first heat exchanger.

8. The battery thermal management system for electric tractors according to claim 1, characterized in that, The third three-way valve includes: port A, port B, and port C. Port A, port B, and port C are interconnected. Port A is connected to the vehicle interior heater core. Port B is connected to port D of the four-way valve. Port C is connected to the air conditioning water pump and the second heat exchanger.

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