A whole vehicle heat distribution system and method for new energy vehicles

Abstract

The present invention discloses a heat distribution system and method for a new energy vehicle. The distribution system includes a lithium battery cooling and heating circuit, a fuel engine cooling circuit, a thermostat, and a charge air cooler. One side of the charge air cooler is connected to the lithium battery cooling and heating circuit, and the other side is connected to the fuel engine cooling circuit through the thermostat. The 1-channel of the thermostat is connected to the particulate filter, the 2-channel is connected to the water pump, the 3-channel is connected to the fuel cell stack, and the 4-channel is connected to the charge air cooler. Through the design of this distribution system, the cold start control of the vehicle and the temperature control function when the vehicle needs the fuel cell system to rapidly pull the load power are realized. This solution couples the lithium battery cooling and heating circuit with the cooling circuit of the fuel engine to achieve heat exchange between two independent systems, reduces the demand for external cooling and heating capabilities of the two systems, and effectively improves the vehicle heat management ability and application effectiveness.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle heat distribution, and particularly relates to a new energy vehicle integrated heat distribution system and method thereof. Background Art

[0002] In the existing integrated vehicle heat management solution, the cooling and heating circuits of the lithium battery and the cooling circuit of the fuel engine are separated, and the temperature is adjusted through the temperature control measures inside the system respectively. Specifically, the cooling and heating circuit of the lithium battery and the cooling circuit of the fuel engine are two separate systems. The lithium battery uses a PTC heater in a dedicated chiller or a heating film directly attached to the surface of the lithium battery for heating up. The lithium battery supplies high voltage power to the PTC or the heating film. The lithium battery uses the air conditioning system in a dedicated chiller for temperature reduction adjustment, and the lithium battery supplies high voltage power to the air conditioning system. The cold start and warming up of the fuel engine completely rely on the heat generated by the fuel cell stack itself, and the system cooling of the fuel engine completely relies on the dedicated radiator in the system.

[0003] The above integrated vehicle heat management solution is likely to cause energy waste in some cases during vehicle operation: when the vehicle needs a cold start and the energy of the lithium battery itself is insufficient, the lithium battery still needs to supply power to the PTC heater or the heating film, which is likely to cause the lithium battery to lose power. When the lithium battery discharges at a temperature below 0°C, it will have a greater impact on the life and capacity of the lithium battery.

[0004] The temperature control measures of the fuel cell mainly rely on the adjustment of the water pump and the radiator. The water pump performs PID adjustment based on the temperature difference between the inlet and outlet of the fuel cell stack, and the radiator performs PID adjustment based on the inlet temperature of the fuel cell stack. However, there is a hysteresis phenomenon in the inlet temperature of the fuel cell stack, and the adjustment of the radiator will also be delayed, resulting in a peak phenomenon in the inlet temperature of the fuel cell stack during rapid system loading, which is not conducive to the stable operation of the fuel cell stack. Summary of the Invention

[0005] The present invention is a new type of new energy vehicle integrated heat distribution solution, which couples the cooling and heating circuit of the lithium battery with the cooling circuit of the fuel engine to realize heat exchange between two independent systems, reduce the demand for external cooling and heating capabilities of the two systems, and improve the ability and application effectiveness of integrated vehicle heat management.

[0006] The present invention is implemented by the following technical solutions: A new energy vehicle's overall vehicle heat distribution system includes a lithium battery cooling and heating circuit and a fuel engine cooling circuit. The lithium battery cooling and heating circuit includes a lithium battery water-cooled plate and a lithium battery water-cooled unit. The fuel engine cooling circuit includes a water pump, a radiator, a particulate filter, a fuel cell stack, an expansion tank, an ion filter, and an engine DCF. It also includes a thermostat and a charge air cooler. One side of the charge air cooler is connected to the lithium battery cooling and heating circuit, and the other side is connected to the 4th channel of the thermostat. The 1st channel of the thermostat is connected to the particulate filter and the radiator. The 2nd channel of the thermostat is connected to the water pump. The 3rd channel is connected to the fuel cell stack. The 4th channel is connected to the charge air cooler.

[0007] The present invention also proposes a distribution method for the overall vehicle heat distribution system of a new energy vehicle, including the following distribution strategies:

[0008] Strategy 1: Distribution strategy during the cold start of the whole vehicle;

[0009] When the vehicle needs to be started after being at a relatively low temperature for a long time, the FCU determines whether the temperature of the lithium battery is higher than T1, where T1 is -2°C to 2°C;

[0010] (A1) When the average temperature of the lithium battery > T1, determine the relationship between the water temperature at the inlet of the fuel cell stack and T2, where T2 is 45°C to 55°C. If the water temperature at the inlet of the fuel cell stack < T2, the thermostat opens the 2nd channel and the 3rd channel, and the engine cooling water circulates through the system's small loop, and the heat generated is completely used for the temperature rise of its own system. When the water temperature of the fuel cell stack rises to T2, the 2nd channel of the thermostat slowly switches to the 1st channel. At this time, both the lithium battery and the engine are at suitable operating temperatures, and the whole vehicle operates at high power;

[0011] (A2) When the average temperature of the lithium battery ≤ T1, determine whether the water temperature at the inlet of the fuel cell stack > T3, where T3 is 0°C to 5°C. When the water temperature at the inlet of the fuel cell stack ≤ T3, the thermostat opens the 2nd channel and the 3rd channel, and the engine self-heats to raise the temperature of the fuel cell stack. When it is determined that the water temperature at the inlet of the fuel cell stack > T3, the thermostat switches from the 2nd channel and the 3rd channel to the 2nd channel, the 3rd channel, and the 4th channel;

[0012] At this time, the FCU continuously judges according to the temperature rise rate of the engine and the temperature rise rate of the lithium battery: At this time, the time t1 for the lithium battery to rise to T1 and the time t2 for the water temperature at the inlet of the fuel cell stack to rise to T2 when the thermostat is in the open state. According to the time difference between t1 and t2, PID adjustment is performed on the opening ratio of the 3rd channel and the 4th channel of the thermostat; until the average temperature of the lithium battery > T1 and the water temperature at the inlet of the fuel cell stack > T2, the cold start of the whole vehicle is completed, and high-power operation is carried out;

[0013] Strategy 2: Distribution strategy during the period when the whole vehicle needs the fuel cell system to rapidly increase power;

[0014] (B1) When the whole vehicle receives a power increase request, first judge whether the current energy of the lithium battery meets the power increase requirement;

[0015] (B2) If the energy of the lithium battery is sufficient, the lithium battery increases the output power, and the engine maintains the existing power and outputs stably; (B3) If the energy of the lithium battery is insufficient, increase the DCF output power of the engine and increase the output current of the fuel cell stack.

[0016] Furthermore, in Strategy 2, in B3, after the FCU judges that the output current of the fuel cell stack increases, the following actions are taken:

[0017] (1) Increase the speed of the water pump to increase the cooling water flow rate and quickly take out the extra heat generated inside the fuel cell stack due to the increased current;

[0018] (2) Switch the thermostat from 1-channel and 3-channel to 1-channel, 3-channel, and 4-channel;

[0019] (3) After the FCU detects that the water temperature entering the fuel cell stack increases, adjust the fan speed and the water temperature of the fuel cell stack drops;

[0020] (4) Switch the thermostat from 1-channel, 3-channel, and 4-channel back to 1-channel and 3-channel.

[0021] Furthermore, mix the first wave of hot water after the increased current with the cold water of the lithium battery system and transport it to the inlet side of the fuel cell stack, determine the opening ratio of the 3-channel and 4-channel, increase the speed of the fan on the radiator, increase the heat exchange capacity of the radiator, and after the water temperature at the inlet of the fuel cell stack drops, the thermostat switches back to 1-channel and 3-channel, and the power increase request of the whole vehicle is completed.

[0022] Furthermore, the flow ratio of the 3-channel and 4-channel is calculated according to the allowable temperature rise difference ΔT1 of the water temperature of the lithium battery, the flow rate q1, and the increase amount Q1 of the heat after the engine is loaded. By controlling the distribution ratio of q3 and q4, ensure that the temperature change of Tin is controlled within 1.5°C:

[0023] Heat absorbed by the lithium battery system: Q2 = q1·C·ΔT1

[0024] Heat dissipated by the engine system: Q3 = η·Q2 = q3·C·ΔT2

[0025] ΔT2 = T out -T4

[0026]

[0027] q2 = q3 + q4

[0028] wherein, q2 is the flow rate of the 1-channel, q3 is the flow rate of the 4-channel, T4 is the outlet temperature of the 4-channel, q4 is the flow rate of the 3-channel, Tin is the inlet water temperature of the fuel cell stack, T out is the outlet water temperature of the radiator, and C is the specific heat capacity of the cooling water.

[0029] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0030] This solution couples the lithium battery cooling and heating circuit with the cooling circuit of the fuel engine. Through two groups of water flow channels, the core components of the two circuits (lithium battery, fuel cell stack of the engine) are maintained at a reasonable operating temperature. On the one hand, the PTC or heating film of the lithium battery water cooling unit is eliminated, saving costs. On the other hand, the irreversible impact of the water temperature hysteresis effect on the fuel cell stack in the fuel cell system is reduced. Only the temperature control strategy needs to be implemented on the engine side, effectively reducing the demand for external cooling and heating capabilities of the two systems, and improving the vehicle heat management ability and application effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the schematic diagram of the vehicle heat distribution system according to the embodiment of the present invention;

[0032] Figure 2 is the schematic diagram of the vehicle cold start process according to the embodiment of the present invention;

[0033] Figure 3 is the schematic diagram of the battery system rapid load process according to the embodiment of the present invention;

[0034] Wherein: 1. water pump; 2. radiator; 3. particulate filter; 4. thermostat; 5. water-to-water intercooler; 6. fuel cell stack; 7. expansion tank; 8. ion filter; 9. lithium battery water cooling plate; 10. lithium battery water cooling unit; 11. engine DCF. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described below with reference to the drawings and embodiments. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] Embodiment 1, this embodiment proposes a vehicle heat distribution system for new energy vehicles, as Figure 1As shown in the figure, it includes a lithium battery cooling and heating circuit, a fuel engine cooling circuit, a thermostat 4, and a water-to-water intercooler 5. The lithium battery cooling and heating circuit includes a lithium battery water-cooled plate 9 and a lithium battery water-cooling unit 10. The fuel engine cooling circuit includes a water pump 1, a radiator 2, a particulate filter 3, a fuel cell stack 6, an expansion tank 7, an ion filter 8, and an engine DCF 11. One side of the water-to-water intercooler 5 is connected to the lithium battery cooling and heating circuit, and the other side is connected to the 4-channel of the thermostat of the fuel engine cooling circuit. The 1-channel of the thermostat is connected to the particulate filter 3 and the radiator, the 2-channel bypasses the radiator and is connected to the water pump 1, the 3-channel bypasses the water-to-water intercooler and is connected to the fuel cell stack 6, and the 4-channel is connected to the water-to-water intercooler 5.

[0037] In this solution, through the coordinated control of the heat transfer medium - the water-to-water intercooler 5 and the multi-channel ball valve thermostat 4, the heat of the two loop systems is reasonably distributed. Through two groups of water flow channels, the core components (lithium battery, fuel cell stack of the fuel engine) of the two loops are maintained at a reasonable working temperature. On the one hand, the PTC or heating film of the lithium battery water-cooling unit is cancelled, saving costs. On the other hand, the irreversible impact of the water temperature hysteresis effect on the fuel cell stack in the fuel cell system is reduced. Only the temperature control strategy needs to be made on the engine side, and there is no need for the vehicle controller to participate in this aspect. The heat transfer efficiency of the water-to-water intercooler can reach more than 96%.

[0038] Embodiment 2, based on the distribution method of the vehicle heat distribution system described in Embodiment 1, is used to achieve two functions:

[0039] Function A: Distribution strategy during the cold start period of the vehicle;

[0040] Function B: Distribution strategy during the period when the vehicle needs the fuel cell system to rapidly increase the load power;

[0041] Specifically, in combination with Figure 2 and Figure 3 , the distribution method described in the embodiments of the present invention will be introduced in detail:

[0042] During the cold start of the whole vehicle, the sign of the completion of the whole vehicle cold start is that at least one of the lithium battery or the fuel engine can start normal power discharge; if the lithium battery and the fuel engine can generate electricity and operate simultaneously, it can provide more sufficient power for the whole vehicle. The starting charge and discharge temperature of the lithium battery is generally around 0°C, and the starting discharge temperature of the fuel engine is above 0°C. The key point of implementing this function is to control the opening ratio and opening time of channels 3 and 4 of the thermostat 4 (inside the thermostat 4 is a ball valve. When channel 3 is fully open, channel 4 is in a fully closed state. When channel 4 is fully open, channel 3 is in a fully closed state. There can also be a state where both channels 3 and 4 are opened at a certain ratio). A water-to-water intercooler is installed in channel 4, which can exchange heat with the lithium battery circuit. Channel 3 bypasses the water-to-water intercooler, and the outlet water of the thermostat 4 directly flows into the stack 6. By changing the opening ratio and time of channels 3 and 4 of the thermostat 4, the heat exchange amount between the two loop systems is determined. When implementing function A, there are two goals: the first goal is the stable rise of the fuel cell stack inlet temperature without rapid temperature changes; the second goal is to further control the start charge and discharge time of the lithium battery to be consistent with the start discharge time of the fuel engine by controlling the heat exchange amount between the two loop systems, so that when the whole vehicle cold start is completed, the whole vehicle can operate at the maximum possible power.

[0043] As Figure 2 shown, the starting operating temperature of the lithium battery needs to be > T1. When the temperature of the battery is lower than T1, charging and discharging the battery will seriously damage the life and capacity of the lithium battery. Generally, T1 is around 0°C. In this embodiment, T1 is -2°C - 2°C, preferably 0°C.

[0044] The general operating temperature of the fuel engine system needs to be at least > T3. T3 is generally at least around 0°C. In this embodiment, T3 is 0°C - 5°C, preferably 5°C. If the operating temperature of the fuel cell is too low, on the one hand, it will lead to a higher activation voltage, a lower output voltage, and a reduced power; on the other hand, a lower temperature will result in less water carried out by the exhaust gas, causing the phenomenon of waterlogging in the stack, which limits the power increase. The temperature at which the fuel engine system can operate normally at high power needs to be at least > T2. At this time, the stack temperature can accelerate the occurrence of chemical reactions. T2 is 45°C - 55°C, preferably 50°C.

[0045] When the whole vehicle is in a sub-zero environment and the vehicle needs to be started and run, the Figure 2 whole vehicle cold start strategy can be carried out. Specifically: when the whole vehicle needs to be started after being at a low temperature for a long time, the FCU (engine controller) judges whether the temperature of the lithium battery is higher than T1.

[0046] 1. When the average temperature of the lithium battery > T1, judge the relationship between the water temperature at the inlet of the fuel cell stack and T2. If the water temperature at the inlet of the fuel cell stack < T2, the thermostat opens channels 2 and 3, and the engine cooling water circulates through the system's small loop, and the heat generated is completely used for the temperature rise of its own system. When the water temperature of the fuel cell stack rises to T2, the 2-channel of the thermostat slowly switches to the 1-channel. At this time, both the lithium battery and the engine are at suitable operating temperatures, and the vehicle can operate at high power.

[0047] 2. When the average temperature of the lithium battery ≤ T1, a part of the heat generated by the engine needs to be used to heat the lithium battery to T1. First, judge the relationship between the water temperature at the inlet of the fuel cell stack and T3. When the water temperature of the engine fuel cell stack ≤ T3, all the heat generated by the engine needs to be used for the temperature rise of the fuel cell stack. After the water temperature at the inlet of the engine fuel cell stack > T3, a part of the heat of the engine can be distributed to the lithium battery system for heating by adjusting the opening degrees of channels 3 and 4 of the thermostat.

[0048] That is: when the average temperature of the lithium battery ≤ T1, judge whether the water temperature at the inlet of the fuel cell stack > T3. When the water temperature at the inlet of the fuel cell stack ≤ T3, the thermostat opens channels 2 and 3, and the engine self-heating is used for the temperature rise of the fuel cell stack. When it is judged that the water temperature at the inlet of the fuel cell stack > T3, the thermostat switches from channels 2 and 3 to channels 2, 3, and 4. At this time, the FCU needs to judge in real time according to the temperature rise rate of the engine and the temperature rise rate of the lithium battery: the time t1 for the lithium battery to rise to T1 and the time t2 for the water temperature at the inlet of the fuel cell stack to rise to T2 when the lower thermostat is in the open state. Perform PID adjustment on the opening ratio of channels 3 and 4 of the thermostat according to the time difference between t1 and t2. During the adjustment process, it is also necessary to pay attention to keeping the water temperature at the inlet of the fuel cell stack rising smoothly without large temperature difference fluctuations. Keep adjusting until the average temperature of the lithium battery > T1 and the water temperature at the inlet of the fuel cell stack > T2 reach the standard time basically the same, and the vehicle's cold start is completed and it can operate at high power.

[0049] It can be seen that during the vehicle's cold start, the heat generated by starting the fuel system is efficiently transferred to the lithium battery heating circuit through the water-water intercooler, thus eliminating the need for the PTC heater originally required for the lithium battery pack and saving system costs.

[0050] During the period of rapid power increase, when the fuel engine system needs to rapidly increase power, such as Figure 3For heat distribution control, the temperature of the water at the outlet of the fuel cell stack 6 rises rapidly. The thermostat opens a certain proportion of the 4-channel while the current increases. A certain proportion of the superheated water flowing out of the 4-outlet of the thermostat enters the 4-channel and exchanges heat with the cold water of the lithium battery system, and then mixes with the hot water in the 3-channel to reduce the water temperature entering the fuel cell stack, so as to ensure that the water temperature at the inlet of the fuel cell stack does not rise rapidly due to the increase in the system power. When the fan of the radiator 2 increases the rotation speed according to the rising inlet water temperature to reduce the water temperature entering the stack, the 4-channel needs to be closed, and the water flow all passes through the 3-channel, and the system starts to operate stably at a constant power again. Similar to Function A, the key point to achieve this function is also to control the opening ratio and opening time of the 3-channel and 4-channel of the thermostat 4. The FCU (Fuel Cell System Controller) needs to calculate the inlet water temperature of the fuel cell stack, the load current of the fuel cell stack, and the current cooling water temperature and flow rate of the lithium battery to determine the reasonable opening ratio of the 3-channel and 4-channel to slow down the rising speed of the inlet water temperature of the fuel cell stack. Through a large number of calibration tests, this function can effectively control the water temperature change at the inlet of the fuel cell stack within 1.5°C during system loading.

[0051] The working temperature of the lithium battery is relatively low, generally needing to be controlled within 15-30°C. Therefore, the outlet water temperature of the lithium battery chiller is generally about 18°C. And when the temperature of the lithium battery fluctuates within 15-30°C, it will not have a significant impact on its performance. However, the fuel cell stack in the fuel engine is very sensitive to temperature. On the one hand, the system needs to be maintained at a reasonable temperature all the time, so that the system can operate at a higher efficiency point and ensure the designed service life; on the other hand, the temperature change rate of the fuel cell stack also needs to be controlled within a certain value to ensure the stable operation of the system.

[0052] In most current engine system cooling solutions, the thermostat only has 1, 2, and 3 channels. During normal system operation, channels 1 and 2 are opened. When the system receives a power increase command and increases the current of the fuel cell stack, the fuel cell stack will simultaneously generate more heat rapidly. At the moment of system power increase, the water temperature at the outlet of the fuel cell stack rises significantly. However, since the fan speed control is only related to the inlet water temperature of the fuel cell stack, the first batch of high-temperature water does not receive more cooling. When it circulates to the inlet of the fuel cell stack, the inlet water temperature of the fuel cell stack will also rise very significantly. At this time, the fan starts to adjust the fan speed according to the change in the inlet water temperature. The inlet water temperature of the fuel cell stack thus slowly returns to the specified temperature. During this power increase process, there will be a peak phenomenon of the inlet water temperature of the fuel cell stack. Frequent temperature peaks will have a greater impact on the power and life of the fuel cell stack.

[0053] This invention corrects this unacceptable phenomenon. The specific strategy is as follows:

[0054] When the whole vehicle receives a power increase request, it first determines whether the current energy of the lithium battery meets the power increase requirement. If the lithium battery has sufficient energy, the lithium battery increases its output power, and the engine maintains its existing power and outputs stably. If the lithium battery energy is insufficient and the DCF output power of the engine needs to be increased, the output current of the fuel cell stack needs to be increased.

[0055] As Figure 3 shown, when the FCU determines that the output current of the fuel cell stack has increased, the following actions need to be taken:

[0056] 1. Increase the speed of the water pump, thereby increasing the cooling water flow rate, and quickly take out the heat generated inside the fuel cell stack due to the increased current.

[0057] 2. Switch the thermostat from the current 1, 3 channels to 1, 3, 4 channels;

[0058] 3. After the FCU detects that the water temperature entering the fuel cell stack has increased, adjust the fan speed, and the water temperature of the fuel cell stack drops;

[0059] 4. Switch the thermostat from 1 channel, 3 channels, 4 channels back to 1 channel, 3 channels.

[0060] Mix the first wave of hot water after the increased current with the cold water of the lithium battery system and transport it to the inlet side of the fuel cell stack to prevent the water temperature at the inlet of the fuel cell stack from rising rapidly. The flow ratio of the 3 channels and 4 channels is calculated according to the allowable temperature rise difference ΔT1 of the water temperature of the lithium battery, the flow rate q1, and the increase amount Q1 of the heat after the engine is loaded. By controlling the distribution ratio of q3 and q4, ensure that the temperature change of Tin is controlled within 1.5 °C:

[0061] The heat absorbed by the lithium battery system: Q2 = q1·C·ΔT1

[0062] The heat dissipated by the engine system: Q3 = η·Q2 = q3·C·ΔT2

[0063] ΔT2 = T out -T4

[0064]

[0065] q2 = q3 + q4

[0066] Among them, q2 is the flow rate of the 1 channel, q3 is the flow rate of the 4 channel, T4 is the outlet temperature of the 4 channel, q4 is the flow rate of the 3 channel, T in is the inlet water temperature of the fuel cell stack, T outis the outlet temperature of the radiator, and C is the specific heat capacity of the cooling water. Since the cold water in the 4 channels is mixed with the hot water in the 3 channels, the water temperature coming out of the fuel cell stack is reduced, and the increase in the water temperature at the inlet of the fuel cell stack is decreased. When the fan detects the increase in the water temperature of the fuel cell stack, the fan speed is increased, and the heat exchange capacity of the radiator is increased. After the water temperature at the inlet of the fuel cell stack starts to decrease, the thermostat directly switches to the 1, 3 channels, and the vehicle power increase request is completed.

[0067] It can be seen that when the fuel system needs to suddenly increase power, the low-temperature water of the lithium battery pack can be used to reduce the water temperature entering the engine of the fuel cell stack. Controlling the water temperature entering the stack can make it rise smoothly or maintain at the required temperature, avoiding large fluctuations in the water temperature entering the stack.

[0068] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A distribution method for the overall vehicle heat distribution system of a new energy vehicle, characterized in that, The vehicle heat distribution system for new energy vehicles includes a lithium battery cooling and heating circuit and a fuel engine cooling circuit. The lithium battery cooling and heating circuit includes a lithium battery water-cooled plate (9) and a lithium battery water-cooled unit (10). The fuel engine cooling circuit includes a water pump (1), a radiator (2), a particulate filter (3), a fuel cell stack (6), an expansion tank (7), an ion filter (8), and an engine (11). It is characterized in that it further includes a thermostat (4) and a charge air cooler (5). One side of the charge air cooler (5) is connected to the lithium battery cooling and heating circuit, and the other side is connected to the 4th channel of the thermostat (4). The 1st channel of the thermostat (4) is connected to the particulate filter (3) and the radiator (2). The 2nd channel of the thermostat (4) is connected to the water pump (1). The 3rd channel is connected to the fuel cell stack (6). The 4th channel is connected to the charge air cooler (5); It further includes the following distribution strategies: Strategy 1: Distribution strategy during cold start of the whole vehicle; When the vehicle needs to be started after being at a low temperature for a long time, the engine controller determines whether the temperature of the lithium battery is higher than T1, where T1 is -2°C to 2°C; (A1) When the average temperature of the lithium battery > T1, determine the relationship between the inlet water temperature of the fuel cell stack and T2, where T2 is 45°C to 55°C. If the inlet water temperature of the fuel cell stack < T2, the thermostat opens the 2nd and 3rd channels, and the engine cooling water circulates through the system's small loop, and the heat generated is completely used for the temperature rise of its own system. When the water temperature of the fuel cell stack rises to T2, the 2nd channel of the thermostat slowly switches to the 1st channel. At this time, both the lithium battery and the engine are at suitable operating temperatures, and the vehicle operates at high power; (A2) When the average temperature of the lithium battery ≤ T1, determine whether the inlet water temperature of the fuel cell stack > T3, where T3 is 0°C to 5°C. When the inlet water temperature of the fuel cell stack ≤ T3, the thermostat opens the 2nd and 3rd channels, and the engine self-heats to raise the temperature of the fuel cell stack. When it is determined that the inlet water temperature of the fuel cell stack > T3, the thermostat switches from the 2nd and 3rd channels to the 2nd, 3rd, and 4th channels; At this time, the engine controller continuously judges according to the temperature rise rate of the engine and the temperature rise rate of the lithium battery: At this time, the time t1 for the lithium battery to rise to T1 and the time t2 for the inlet water temperature of the fuel cell stack to rise to T2 when the thermostat is in the open state. Perform PID adjustment on the opening ratio of the 3rd and 4th channels of the thermostat according to the time difference between t1 and t2; until the average temperature of the lithium battery > T1 and the inlet water temperature of the fuel cell stack > T2, the cold start of the whole vehicle is completed, and high-power operation is carried out; Strategy 2: Distribution strategy during the period when the vehicle needs rapid power loading of the fuel cell system; (B1) When the vehicle receives a power increase request, first determine whether the current energy of the lithium battery meets the power increase requirement; (B2) If the lithium battery has sufficient energy, the lithium battery increases its output power, and the engine maintains the existing power and outputs stably; (B3) If the lithium battery does not have enough energy, increase the engine output power and increase the output current of the fuel cell stack.

2. The distribution method of the new energy vehicle's overall vehicle heat distribution system according to claim 1, wherein: In Strategy 2, in B3, when the engine controller determines that the output current of the fuel cell stack has increased, the following actions are taken: (1) Increase the speed of the water pump to increase the cooling water flow rate and quickly take out the extra heat generated inside the fuel cell stack due to the increased current; (2) Switch the thermostat from one-channel and three-channel to one-channel, three-channel, and four-channel; (3) After the engine controller detects an increase in the water temperature entering the reactor, adjust the fan speed, and the water temperature of the fuel cell stack drops; (4) Switch the thermostat from one-channel, three-channel, and four-channel back to one-channel and three-channel.

3. The distribution method of the new energy vehicle's overall vehicle heat distribution system according to claim 2, wherein: Mix the first wave of hot water after current increase with the cold water of the lithium battery system and transport it to the inlet side of the fuel cell stack. Determine the opening ratio of the three-channel and four-channel, increase the fan speed on the radiator, increase the heat exchange capacity of the radiator. After the water temperature at the inlet of the fuel cell stack drops, switch the thermostat back to one-channel and three-channel, and the vehicle's power increase request is completed.

4. The distribution method of the new energy vehicle's overall vehicle heat distribution system according to claim 3, characterized in that: The opening ratios of the 3-channel and 4-channel are calculated based on the allowable temperature rise ΔT1 of the water temperature of the lithium battery, the flow rate q1, and the increase Q1 in heat after the engine load, and by controlling the distribution ratio of q3 and q4, ensure that the in temperature change of is controlled within 1.5°C; Heat absorbed by the lithium battery system: Q2 = q1·C·ΔT1 Heat dissipated by the engine system: Q3 = q3·C·ΔT2 ΔT2 = T out - T4 q2 = q3 + q4 Among them, q2 is the flow rate of Channel 1, q3 is the flow rate of Channel 4, T4 is the outlet temperature of Channel 4, q4 is the flow rate of Channel 3, T in is the inlet water temperature of the stack, T out is the outlet water temperature of the radiator, and C is the specific heat capacity of the cooling water.

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