Vehicle energy thermal safety integrated system and control method thereof

Abstract

The application discloses a vehicle energy and heat safety integrated system. A turbine-supercharging coaxial device maintains self-sustaining carbon dioxide circulating pressure and does not participate in power generation; a turbine expansion part of the turbine-supercharging coaxial device drives a steam turbine to generate power by exhaust waste heat; a high-pressure energy supply tank maintains a constant temperature of 35 DEG C and a constant pressure of 7.2-7.3 MPa, and an equivalent condensing pressure is locked at 7.1 MPa; main and auxiliary batteries are alternately used for driving power supply, and a third battery group provides emergency standby power supply; battery cold and heat management and fire fighting are provided by a carbon dioxide direct cooling / heat branch and a fire fighting storage tank, and electric heating PTC or electric compression refrigeration equipment is not needed; in winter, a high-pressure heat compensation loop returns the working medium of a heat user branch after heat exchange to an intermediate stage of a compression part, so that circulating flow balance is maintained. The endurance is determined by the capacity of a fuel tank, and the capacity of the battery is 1 / 3-1 / 4 of that of a pure electric vehicle. Energy compensation is less than 5 minutes, endurance attenuation in winter is less than 3%, the comprehensive efficiency of the system is 50%-55%, and the system is suitable for various electric drive vehicles.

Description

Technical Field

[0001] This invention relates to the field of integrated vehicle energy and thermal safety technology, specifically to an integrated system that integrates energy management, battery thermal management, and fire safety, with the turbine-boost coaxial device pressure self-sustaining as its core. Background Technology

[0002] Existing vehicle powertrain systems are mainly divided into two technical routes based on energy source: pure electric drive and fuel-powered drive (including range-extended systems). Both suffer from the same fundamental drawback—drive power and heating / cooling power are coupled, requiring the energy source to simultaneously respond to drive and transient heating / cooling demands.

[0003] In pure electric drive systems, the power battery is not only the sole energy storage unit but also serves as a power buffer for both driving and thermal management. To meet the demands for driving range and transient power, battery pack capacity has been continuously increased, currently reaching 70-100 kWh in mainstream models, with battery packs weighing 450-550 kg, accounting for 25%-30% of the vehicle's curb weight. Fast charging still takes 30 minutes to several hours, making recharging far less convenient than refueling; driving range decreases by 20%-30% in low-temperature environments. High-energy-density ternary lithium batteries have a thermal runaway threshold as low as 200°C, rapidly igniting and exploding after puncture, releasing highly toxic gases and flames at 800-1200°C. The increased inertia of the large battery pack during a collision places an additional burden on the vehicle structure and occupant safety.

[0004] In the range-extended electric vehicle (REEV) approach, the internal combustion engine must also dynamically follow changes in drive power and battery state of charge (SOC), frequently deviating from its optimal efficiency range, resulting in a significant decrease in overall efficiency. Variable operating conditions also bring a chain of problems such as thermal stress shocks, shortened component lifespan, and increased noise and vibration.

[0005] Existing vehicle-mounted systems design "power," "thermal management," and "safety" as independent subsystems, lacking integrated design. While existing transcritical CO2 vehicle-mounted thermal management systems use CO2 as the working fluid, the cycle power still relies on electric compressors, failing to achieve pressure self-sufficiency. Existing vehicle-mounted turbine waste heat power generation devices aim to output electricity, requiring the turbine power to simultaneously meet compression and power generation needs, resulting in high control coupling. Existing battery-powered fire suppression systems are mostly independent extinguishing devices, lacking synergy with the thermal cycle system. These problems are particularly pronounced in large and medium-sized vehicles (trucks, refrigerated trucks, RVs, and intercity buses) due to their continuous heating and cooling loads, ample space, and long operating mileage.

[0006] To address the above problems, the present invention provides an integrated vehicle energy and thermal safety system. Summary of the Invention

[0007] 3.1 Purpose of the Invention

[0008] This invention provides an integrated system with pressure self-sustaining turbine-boost coaxial device as the core, integrating energy management, battery thermal management and fire safety, to solve problems such as energy replenishment anxiety, winter range reduction, high energy consumption of battery thermal management, battery fire safety and safety hazards of large-capacity batteries.

[0009] 3.2 Technical Solution

[0010] System thermal design principles

[0011] This system is built upon the following three design principles:

[0012] (1) The purpose of the turbine-boost coaxial unit is solely to maintain system pressure—ensuring that the most unfavorable pressure at the end of the high-pressure power supply pipe is not lower than 7.1 MPa, and it does not participate in power generation. Waste heat is an inevitable byproduct of pressure maintenance.

[0013] (2) The high-pressure power supply tank is maintained at a constant temperature of 35℃ and a constant pressure of 7.2~7.3MPa, serving as the basic reference point for the system's thermodynamic state; the equivalent condensing pressure is locked at 7.1MPa±0.1MPa, ensuring that the working fluid state at the recooler outlet is uniquely determined (29.3℃ / dryness). After throttling, the evaporation temperature stabilizes at 5~10℃.

[0014] (3) When the heat load is much greater than the cold load in winter, the working fluid after heat exchange in the heat user branch returns directly to the intermediate stage of the compressor through the high-pressure heat compensation circuit, avoiding the return through the low-pressure return pipe, which would cause excessive flow and pressure imbalance on the low-pressure side; the high-pressure heat compensation circuit and the low-pressure return pipe operate independently and work together to maintain the flow balance of the circulating working fluid.

[0015] The following is a detailed explanation of each subsystem.

[0016] Main loop path

[0017] The main circulation path of the system is as follows: cold side of the regenerator (5~10℃) → three-stage compression → cold side of the preheater → heating by carbon dioxide heating device → expansion → hot side of the preheater → waste heat power generation section → waste heat utilization section → air cooler (excess heat not consumed in the temperature utilization channel is discharged to the atmosphere through the air cooler) → hot side of the regenerator (about 35℃) → high pressure energy supply tank (35℃, 7.2~7.3MPa) → high pressure energy supply pipe transportation → equivalent condensing pressure regulation → end utilization → low pressure return gas pipe → deep drying filter → low pressure return gas tank → cold side of the regenerator (5~10℃).

[0018] Turbine-boost coaxial unit

[0019] The turbine-boost coaxial unit is the core power mechanism of this system. The turbine expansion section and compression section are mounted on the same main shaft and rigidly connected coaxially. All the work done by the turbine expansion drives the compression section through the coaxial shaft, maintaining the pressure difference and flow of the working fluid. The compression section pressurizes the low-pressure working fluid and sends it to the carbon dioxide heating device, where it is heated by the high-temperature flue gas, forming a continuous cycle. The turbine-boost coaxial unit does not participate in power generation; its purpose is solely to maintain system pressure, ensuring that the most unfavorable pressure at the end of the high-pressure power supply pipe is not lower than 7.1 MPa.

[0020] The turbine-booster coaxial unit has a minimum safe operating power threshold, which is not lower than the power corresponding to its surge boundary (10%~30% of the rated power). When the power is lower than this threshold, the turbine enters an unstable operating condition. The unit operates continuously and stably above the minimum safe operating power threshold and will not stop due to changes in hot or cold loads.

[0021] High-pressure power supply tank – 35℃ constant temperature, 7.2~7.3MPa constant pressure standard

[0022] The high-pressure power supply tank maintains a constant temperature of 35°C and a constant pressure of 7.2~7.3MPa, serving as the fundamental reference point for the system's thermodynamic state. Regardless of winter or summer, the temperature and pressure references of the high-pressure power supply tank remain unchanged.

[0023] - Summer: The working fluid is cooled to 35℃ and 7.2~7.3MPa by the regenerator and enters the high-pressure power supply tank → equivalent condensing pressure is adjusted (7.1MPa) → throttling expansion refrigeration.

[0024] - Winter: The working fluid is cooled to 35℃ and 7.2~7.3MPa by the regenerator before entering the high-pressure power supply tank. The high-pressure heat compensation circuit returns the working fluid after heat exchange in the heat user branch directly to the intermediate stage of the compressor.

[0025] Equivalent condensing pressure – refrigeration pressure reference

[0026] The equivalent condensing pressure is the refrigeration pressure benchmark for the transcritical carbon dioxide cycle. Under air conditioning conditions, the equivalent condensing pressure is locked at 7.1 MPa, corresponding to a saturation temperature of 29.3℃ (dryness fraction). This state point represents the saturated liquid state of the high-pressure side carbon dioxide working fluid after cooling in the recooler and before entering the throttling expansion stage.

[0027] With the equivalent condensing pressure fixed, the working fluid state at the recooler outlet is uniquely determined, and the evaporation temperature after throttling expansion is stabilized at 5~10℃, providing a stable cold source for battery thermal management, drive motor cooling, cabin refrigeration, refrigerated truck cargo compartment refrigeration, vehicle refrigerator and vehicle computing chip heat dissipation.

[0028] In a specific implementation, a pressure regulating valve is installed on the inlet pipe of the equivalent condensing pressure regulating unit, and a temperature sensor and a pressure sensor are installed on the outlet pipe. A temperature regulating valve is installed on the cold side inlet pipe (low-pressure return gas pipe) of the recooler. The pressure sensor collects the outlet working fluid pressure signal of the equivalent condensing pressure regulating unit, and the temperature sensor collects the outlet working fluid temperature signal (i.e., subcooling). Both are fed back to the PID controller. The PID controller outputs a control signal to the actuator of the pressure regulating valve according to the pressure deviation, and controls the flow rate of the working fluid entering the equivalent condensing pressure regulating unit by adjusting the opening of the pressure regulating valve, thereby stabilizing the equivalent condensing pressure within the range of 7.1MPa±0.1MPa.

[0029] The PID controller outputs a control signal to the actuator of the temperature regulating valve based on the temperature deviation (subcooling deviation). By adjusting the opening of the temperature regulating valve, it controls the flow rate of low-pressure return gas entering the cold side of the recooler, thereby changing the heat exchange between the cold and hot sides of the recooler. This controls the subcooling of the working fluid outlet at the target value, ensuring that the working fluid at the recooler outlet is always in a saturated liquid state at 29.3℃ (dryness). )state.

[0030] The recooler operates as follows: low-temperature return gas (5~10℃) from the low-pressure return gas pipe flows through the cold side of the recooler and exchanges heat counter-currently with the high-pressure working fluid on the hot side of the recooler. The residual cooling from the low-temperature return gas carried by the low-pressure return gas pipe itself cools the high-pressure working fluid to a saturation temperature of 29.3℃ corresponding to 7.1MPa. The cooled 7.1MPa saturated liquid working fluid is then throttled and depressurized by an electronic expansion valve to the low-pressure return gas pipe pressure (3.6~3.98MPa), where it absorbs heat and evaporates in the terminal evaporator to produce the stable 5~10℃ cooling capacity required by the user.

[0031] Steam turbine waste heat power generation

[0032] The exhaust gas from the turbine expansion section of the turbine-booster coaxial unit (350~450℃) is preheated and compressed by a preheater (65℃→200~350℃) before entering the steam generator to produce superheated steam (2~5MPa, 300~380℃), which drives a small steam turbine to generate electricity (3~8kW). The generated electricity is used to charge the battery pack. The exhaust steam from the steam turbine outlet is condensed by a condenser and returned to the steam generator, forming a closed Rankine cycle.

[0033] The power output of a steam turbine is determined by the waste heat from the turbine exhaust. When the heating or cooling load increases, the waste heat used for power generation decreases, resulting in lower power output; when the heating or cooling load decreases, the waste heat used for power generation increases, resulting in higher power output. The power output does not change with the vehicle's driving conditions. The remaining waste heat is preferentially supplied to heating, hot water, cooking, drying, defrosting, and other heat utilization needs. Excess heat that is not consumed after heat utilization is discharged into the atmosphere via an air cooler.

[0034] Dual-channel temperature and pressure utilization

[0035] The system utilizes both heat and cold through two physical channels, sharing the same carbon dioxide working fluid cycle:

[0036] Temperature Utilization Channel: Sensible heat is directly extracted from high-temperature thermal energy and supplied to cabin heating, domestic hot water, cooking, clothes drying, defrosting, and other heat needs through a heat exchanger; excess heat not consumed in the temperature utilization channel is discharged to the atmosphere via an air cooler. During summer cooling operation, since there is no heating demand, the working fluid, after passing through the waste heat utilization section, directly enters the air cooler to discharge heat, and is then cooled to 35°C by a regenerator before entering the high-pressure energy supply tank, ensuring the thermal balance of the transcritical carbon dioxide cycle.

[0037] Pressure utilization channel: High-pressure carbon dioxide working fluid (7.1MPa saturated liquid) is throttled and expanded to low-pressure return gas pipe pressure (3.6~3.98MPa), and the latent heat of phase change is used to generate cooling capacity (5~10℃) to supply the cooling needs of cabin air conditioning, battery cooling, drive motor cooling, refrigerated truck cargo compartment cooling, vehicle refrigerator and vehicle computing chip heat dissipation.

[0038] Thermal compensation circuit – winter heat deficit compensation

[0039] The high-pressure thermal compensation circuit connects the outlet of the heat user branch to the inlet of the intermediate stage of the compressor. When the heat load is much greater than the cold load in winter, the working fluid (40~50℃) after heat exchange in the heat user branch (heating, hot water, cooking, etc.) returns directly to the intermediate stage of the compressor through the high-pressure thermal compensation circuit, operating independently from the low-pressure return gas pipe.

[0040] The working fluid in the hot user branch flows through the high-pressure thermal compensation circuit, while the working fluid in the cold user branch (battery thermal management, air conditioning, refrigerator, etc.) expands through throttling and then flows back to the inlet of the compression section through the low-pressure return pipe. The two do not interfere with each other and work together to maintain the balance of the circulating working fluid flow.

[0041] The high-pressure thermal compensation circuit is only activated in winter, and its working fluid flow rate is dynamically adjusted by the temperature control mode according to the heating load: the flow rate increases when the heating load increases and decreases when the heating load decreases.

[0042] Multiple battery switching and independent power supply for drive

[0043] The first and second battery packs are charged and discharged alternately, and the switching control unit seamlessly switches when the SOC drops to the threshold (20~100ms). The electrical energy required for vehicle driving is independently provided by the battery pack in the discharged state—there is no power follow relationship between power generation and driving.

[0044] The third battery pack is always kept fully charged and does not participate in daily charge and discharge cycles. It only switches in as an emergency (≤5ms) in case of switching failure or abnormal power generation.

[0045] Electric drive subsystem

[0046] The electric drive subsystem comprises a drive motor and a motor controller. The drive motor provides propulsion to the vehicle and is powered by the currently discharging battery pack via a DC bus. The motor controller receives torque / speed commands from the vehicle control unit and adjusts the drive motor's output power based on the battery pack's current discharge capacity and the vehicle's operating status. The heat generated by the drive motor during operation is regulated by either a direct carbon dioxide cooling branch (5~10℃) or a direct heating branch (40~50℃)—cooling during summer or sustained high loads and preheating during cold starts in winter, eliminating the need for a separate electric heating or electric drive cooling system.

[0047] Vehicle control unit

[0048] The vehicle control unit includes an Energy Management System (EMS), a Battery Management System (BMS), and a PID controller. The EMS is signal-connected to the BMS, monitoring the SOC of each battery pack and the vehicle's power requirements in real time. The PID controller is signal-connected to the equivalent condensing pressure regulating unit, outputting control signals to the pressure regulating valve and temperature regulating valve based on the temperature and pressure deviation at the high-pressure power supply tank outlet, maintaining stable equivalent condensing pressure. The vehicle control unit also outputs control signals to the switching control unit of the multi-battery pack switching management subsystem, controlling the alternating charging and discharging of the first and second battery packs, and automatically switching to the third battery pack in case of switching failure or power generation abnormality; it outputs control signals to the flow regulating valve of the high-pressure thermal compensation circuit, dynamically adjusting the thermal compensation flow according to the heating load; and it outputs control signals to the battery thermal management and fire protection subsystem, controlling the on / off of the direct cooling / direct heating branches and the release of the fire-fighting tank. Through the above signal connections and coordinated control, the vehicle control unit decouples the drive power from the heating and cooling loads, ensuring that the steam turbine power generation does not change with the vehicle's driving conditions.

[0049] Battery capacity design principles

[0050] In this system, the capacity of the first and second battery packs is 1 / 3 to 1 / 4 of the capacity of the power battery pack of a pure electric vehicle of the same class (e.g., 25 to 33 kWh), which is determined by the peak power requirement of the drive motor and the basic pure electric range, corresponding to a basic pure electric range of about 150 to 200 km.

[0051] The total driving range of a vehicle is determined by the capacity of its fuel tank. The mechanism is as follows: fuel is used to sustain the continuous operation of the transcritical carbon dioxide cycle. This cycle, while meeting the vehicle's thermal management and fire-fighting needs, uses waste heat from the turbine expansion section to drive a steam turbine to generate electricity and recharge the battery pack, thus providing the vehicle with continuous pure electric driving capability. Therefore, the fuel tank capacity essentially determines the duration and total energy replenishment of waste heat power generation, thereby determining the vehicle's total driving range.

[0052] It should be noted that while the steam turbine's power output (3-8 kW) is lower than the peak power of the drive motor, the design goal of this system is not to completely eliminate the battery's stored energy during operation. Instead, it utilizes waste heat to generate electricity and continuously replenish the battery's charge over long periods, maintaining the battery's state of charge (SOC) within a safe range between refueling intervals. The instantaneous high power required by the drive motor is provided by the battery pack, while waste heat generation plays a supplementary role over long time scales, complementing each other in terms of power level and time scale.

[0053] Battery thermal management and fire protection

[0054] Battery thermal management is provided by a direct carbon dioxide cooling / heating branch: when the battery temperature is above 35℃, it connects to the direct cooling branch (5~10℃); when the battery temperature is below 5℃, it connects to the direct heating branch (40~50℃). Battery temperature regulation is achieved through the phase change heat of the carbon dioxide circulating working fluid, eliminating the need for additional electric heating PTC or electric compression refrigeration equipment. Only the vehicle control solenoid valves and sensors consume a small amount of control power. Similarly, the drive motor can be preheated by the carbon dioxide direct heating branch (40~50℃) during cold starts in winter, and cooled by the carbon dioxide direct cooling branch (5~10℃) during summer or continuous high-load operation, eliminating the need for an additional independent electric heating or electric drive cooling device.

[0055] Battery fire suppression is provided by a dedicated carbon dioxide fire suppression tank: the tank (5~15L) is connected to the working fluid pump outlet via a make-up gas branch, and is automatically maintained at full pressure (10~12MPa) by the EMS. When a thermal runaway warning is triggered (temperature rise rate ≥2℃ / s for 3 seconds), the solenoid valve opens, and high-pressure carbon dioxide, after being depressurized to 0.3~0.8MPa, is sprayed onto the surface of the battery modules through the internal spray pipes of the battery pack, achieving oxygen isolation, cooling, and chemical inerting fire extinguishing effects. The fire suppression tank can be refilled.

[0056] The product claims and method claims of this invention belong to the same inventive concept, and both revolve around the core inventive point of "turbine-boost coaxial pressure self-sustaining + integrated carbon dioxide thermal safety + three-battery decoupled power supply", which meets the requirement of unity of invention in Article 31 of the Patent Law.

[0057] 3.3 Beneficial Effects

[0058] 1. The turbine-boost coaxial unit only maintains pressure self-sustaining and does not participate in power generation; the 35°C constant temperature tank provides a constant reference point, and the 7.1MPa equivalent condensing pressure causes the cycle to converge to a defined thermodynamic state.

[0059] 2. When the heat load is much greater than the cold load in winter, the high-pressure heat compensation circuit will return the working fluid after heat exchange in the heat user branch directly to the intermediate stage of the compressor section to maintain the flow balance of the circulating working fluid and avoid excessive flow and pressure imbalance in the low-pressure return gas pipe.

[0060] 3. The steam turbine's power generation is determined by waste heat and does not follow the drive conditions; the drive is independently powered by the battery, with a switching time of 20~100ms and a standby time of ≤5ms. The total capacity of the battery pack is 1 / 3 to 1 / 4 of that of pure electric vehicles in the same class, with shallow charging and discharging and a lifespan of ≥5000 cycles.

[0061] 4. The carbon dioxide heating device uses the high-temperature flue gas in the combustion chamber to heat the working fluid, and the waste heat is utilized in stages, with a system overall efficiency of 50%~55%.

[0062] 5. Battery thermal management (cooling at 5~10℃ / heating at 40~50℃) and fire protection are provided by carbon dioxide circulation, which does not consume power battery energy, requires zero additional hardware, and is rechargeable.

[0063] 6. It is compatible with a variety of clean fuels, with a carbon dioxide working fluid GWP of 1, and does not fall under the category of fluorinated greenhouse gases such as hydrofluorocarbons (HFCs) controlled by the "Regulations on the Management of Ozone Depleting Substances".

[0064] 7. The battery capacity is 1 / 3 to 1 / 4 of that of pure electric vehicles, and it uses intrinsically safe battery cells with a shallow charge and discharge life of ≥5000 cycles, reducing the total amount of retired batteries.

[0065] 8. The three core distinguishing features of this invention constitute a collaborative innovation mechanism:

[0066] • The turbine-boost coaxial unit only maintains pressure self-sustaining and does not participate in power generation, so that the turbine operating condition is not disturbed by the power generation load, and provides a stable thermodynamic reference for the cycle;

[0067] • The 7.1 MPa equivalent condensing pressure lockout ensures a unique determination of the working fluid state at the recooler outlet (29.3℃ / dryness). After throttling, the evaporation temperature stabilizes at 5~10℃, providing thermodynamic assurance for a stable cold source throughout the year;

[0068] The high-pressure thermal compensation circuit independently diverts the working fluid from the heat user branch to the intermediate stage of the compressor in winter, solving the problem of circulating working fluid flow imbalance when the heat load is much greater than the cold load in winter. The synergy of these three elements enables the system to achieve a winter range reduction of ≤3%, an overall efficiency of 50%~55%, and no need for additional electric heating / cooling equipment, all while ensuring complete decoupling of drive power from heating and cooling loads.

[0069] The aforementioned effect cannot be achieved by any single distinguishing feature alone, nor is it a simple superposition of the effects of the discrete modules in the prior art; it is an unexpected technical effect. Attached Figure Description

[0070] Figure 1 System overall architecture and loop principle diagram

[0071] Figure 2 Multi-battery switching management flowchart Detailed Implementation

[0072] This invention is applicable to all types of electric vehicles, including but not limited to large and medium-sized vehicles such as trucks, refrigerated trucks, motorhomes, and intercity buses. With the reduction of system costs and miniaturization optimization, it can also be extended to ordinary passenger cars.

[0073] Example 1: Trucks / Heavy Trucks

[0074] The methanol storage tank has a capacity of 300L, providing a range of approximately 1000km. The turbine-boost coaxial unit has a rated power of 130kW (single unit), with a surge boundary power of approximately 13kW (10% of rated power) and a minimum safe operating power threshold of 13kW. The three-cell battery system consists of 50kWh batteries A and B, and 10kWh battery C, providing a pure electric range of approximately 300km. The high-pressure power supply tank maintains a constant temperature of 35℃ and a constant pressure of 7.2~7.3MPa, with an equivalent condensing pressure locked at 7.1MPa. The steam turbine waste heat power generation module has a capacity of 8kW, and the carbon dioxide fire-fighting storage tank has a capacity of 15L.

[0075] Under winter operating conditions, when the heating load increases, the working fluid after heat exchange in the heat user branch returns directly to the intermediate stage of the three-stage compressor via the high-pressure heat compensation circuit, and the flow rate is dynamically adjusted by the temperature control mode.

[0076] The preheater preheats the compressed working fluid from 65°C to 300°C, and the regenerator preheats the low-pressure return gas from 5°C to 35°C. Battery thermal management and fire protection configurations are as described in the previous technical solution. The overall efficiency is approximately 53%.

[0077] Example 2: Refrigerated truck

[0078] The methanol storage tank has a capacity of 150L, ​​providing a range of approximately 600km. The turbine-boost coaxial unit has a rated power of 60kW, with a surge threshold power of approximately 12kW. The three-cell battery system consists of 30kWh batteries (A / B) and 5kWh battery pack (C), providing a pure electric range of approximately 180km. The high-pressure power supply tank maintains a constant temperature of 35℃ and a constant pressure of 7.2~7.3MPa, with an equivalent condensing pressure locked at 7.1MPa. The steam turbine waste heat power generation module has a capacity of 5kW, and the carbon dioxide fire-fighting storage tank has a capacity of 10L.

[0079] The refrigerated branch maintains a warehouse temperature of 0~5℃; the refrigerated branch maintains a temperature of -18℃. When the cooling load increases, the waste heat used for power generation decreases.

[0080] The high-voltage thermal compensation circuit is activated as needed during winter. Battery thermal management and fire protection configurations are as described above. Overall efficiency is approximately 52%.

[0081] Example 3: Motorhome / RV

[0082] The methanol storage tank has a capacity of 150L, ​​providing a range of approximately 600km. The turbine-boost coaxial unit has a rated power of 40kW, with a surge threshold power of approximately 8kW. The three-cell battery system consists of 20kWh batteries (A / B) and 5kWh battery pack (C), providing a pure electric range of approximately 120km. The high-pressure power supply tank maintains a constant temperature of 35℃ and a constant pressure of 7.2~7.3MPa, with an equivalent condensing pressure locked at 7.1MPa. The steam turbine waste heat power generation module has a capacity of 4kW, and the carbon dioxide fire-fighting storage tank has a capacity of 8L.

[0083] In the parked state, the turbine operates continuously at its surge boundary power of 8kW, while the steam turbine generates electricity (4kW) to charge the battery pack. The 20L insulated water tank provides 40-60℃ hot water for showering and boiling water (100℃) via a waste heat exchanger; cooking and insulation are supplied by a medium-temperature waste heat branch (100-200℃); the refrigerator is independently cooled by a carbon dioxide direct cooling branch (5-10℃); the building envelope's dry air circulation achieves windless radiant temperature control; clothes drying is achieved through waste heat hot air circulation (40-60℃). The high-voltage thermal compensation circuit is activated as needed in winter. Battery thermal management and fire protection configurations are as described above. The overall efficiency is approximately 50%.

[0084] Example 4: Intercity Bus

[0085] The methanol storage tank has a capacity of 200L, providing a range of approximately 700km. The turbine-boost coaxial unit has a rated power of 100kW, with a surge threshold power of approximately 20kW. The three-cell battery system consists of 40kWh batteries (A / B) and 8kWh battery (C), providing a pure electric range of approximately 240km. The high-pressure power supply tank maintains a constant temperature of 35℃ and a constant pressure of 7.2~7.3MPa, with an equivalent condensing pressure locked at 7.1MPa. The steam turbine waste heat power generation module has a capacity of 6kW, and the carbon dioxide fire-fighting storage tank has a capacity of 12L.

[0086] The passenger area air conditioning prioritizes heat consumption, with surplus heat used for power generation. Winter heating is provided by waste heat, while summer cooling is provided by a carbon dioxide cycle. The high-voltage thermal compensation circuit is activated as needed in winter. Battery thermal management and fire protection configurations are as described above. The overall efficiency is approximately 52%.

[0087] Example 5: Ordinary passenger car

[0088] The methanol storage tank has a capacity of 60L, providing a range of approximately 400km. The turbine-boost coaxial unit has a rated power of 25kW, with a surge threshold power of approximately 5kW (20% of the rated power) and a minimum safe operating power threshold of 5kW. The three-cell battery system consists of 12kWh batteries A and B, and a 3kWh battery pack C, providing a pure electric range of approximately 80km. The high-pressure power supply tank maintains a constant temperature of 35℃ and a constant pressure of 7.2~7.3MPa, with an equivalent condensing pressure locked at 7.1MPa. A 2kW waste heat power generation module from the steam turbine and a 5L carbon dioxide fire suppression tank are included. The crew cabin air conditioning (cooling / heating) is powered by carbon dioxide circulation and waste heat; battery thermal management and fire suppression configurations are as described previously. The overall efficiency is approximately 51%.

[0089] The main charging source for the third battery pack is the steam turbine power generation module. In addition, it can be connected to the vehicle-mounted photovoltaic power generation module, with photovoltaic power generation as the preferred supplementary charging source. When there is sufficient sunlight, it can float charge the third battery pack, so that it can maintain its state of charge when the vehicle is parked or the thermal system is not started.

Claims

1. A vehicle energy and thermal safety integrated system, characterized in that, include: Vehicle control unit, thermal energy supply subsystem, turbine-boost coaxial device, steam turbine waste heat power generation module, high-pressure energy supply tank, equivalent condensing pressure regulating unit, high-pressure thermal compensation circuit, multi-battery pack switching management subsystem, battery thermal management and fire protection subsystem, and electric drive subsystem; The heat supply subsystem includes a combustion chamber, a fuel storage tank, and a carbon dioxide heating device. Clean fuel is burned in the combustion chamber to produce high-temperature flue gas, and the high-temperature flue gas transfers heat to the carbon dioxide working fluid through the carbon dioxide heating device. The turbine-boosting coaxial device includes a turbine expansion section, a compression section, and a coaxial main shaft. All the turbine expansion work is driven by the coaxial main shaft to maintain the pressure difference and flow of the working fluid. The compression section pressurizes the low-pressure working fluid and sends it to the carbon dioxide heating device, where it is heated by the high-temperature flue gas, forming a continuous closed thermodynamic cycle. The turbine-boosting coaxial device does not participate in power generation; its purpose is only to maintain the system pressure and ensure that the most unfavorable pressure at the end of the high-pressure power supply pipe is not lower than 7.1 MPa. The exhaust waste heat from the turbine expansion section of the turbine-boosting coaxial device enters the steam turbine waste heat power generation module to drive the steam turbine to generate electricity, and the generated electricity is used to charge the battery pack. The high-pressure energy supply tank maintains a preset constant temperature and pressure, serving as a basic reference point for the system's thermal state. The equivalent condensing pressure regulating unit is used to lock the equivalent condensing pressure of carbon dioxide in the transcritical cycle at a preset reference value. The high-pressure thermal compensation circuit connects the outlet of the heat user branch to the intermediate stage of the compressor. When the heat load is much greater than the cold load in winter, the working fluid after heat exchange in the heat user branch returns directly to the intermediate stage of the compressor through the high-pressure thermal compensation circuit. It operates independently from the low-pressure return gas pipe to maintain the balance of the circulating working fluid flow. The multi-battery pack switching management subsystem includes a first battery pack, a second battery pack, a third battery pack, and a switching control unit; the first battery pack and the second battery pack are configured to alternately charge and discharge, and the third battery pack is configured to always be in a fully charged standby state. When the switching of the first and second battery packs fails or there is an abnormal power generation, it automatically switches to the DC bus to provide emergency power supply. The battery thermal management and fire protection subsystem includes a carbon dioxide direct cooling / heating branch and a dedicated fire protection tank. The direct cooling / heating branch is used for temperature regulation of the battery and drive motor. The fire protection tank is connected to the outlet of the working fluid pump and automatically maintains full pressure. In case of thermal runaway, it releases carbon dioxide to extinguish the fire. The electric drive subsystem includes a drive motor and a motor controller, which are powered by a battery pack that is currently in a discharged state via a DC bus. The power generation capacity of the steam turbine is determined by the exhaust waste heat from the turbine expansion section of the turbine-boosting coaxial device and does not follow changes in vehicle driving conditions; the vehicle driving power is provided independently by the battery pack; there is no power following relationship between power generation and driving. The vehicle control unit is connected to the equivalent condensing pressure regulating unit, the multi-battery pack switching management subsystem, and the battery thermal management and fire protection subsystem via signal connection, and coordinates the operation of each subsystem.

2. The system according to claim 1, characterized in that, The high-pressure power supply tank maintains a constant temperature of 35°C and a constant pressure of 7.2~7.3MPa; the equivalent condensation pressure is locked at 7.1MPa±0.1MPa, corresponding to a saturated liquid temperature of 29.3°C and a dryness fraction of [missing information]. The equivalent condensing pressure regulating unit is equipped with a pressure regulating valve on its inlet pipe and a temperature sensor and a pressure sensor on its outlet pipe. A temperature regulating valve is also installed on the cold-side inlet pipe (low-pressure return gas pipe) of the recooler. The pressure and temperature sensors are connected to a PID controller, which in turn is connected to the actuators of the pressure and temperature regulating valves. The pressure and temperature regulating valves adjust their respective valve core openings to control the working fluid pressure and temperature of the equivalent condensing pressure regulating unit. After the working fluid expands to the low-pressure return gas pipe pressure (3.6~3.98MPa) via an electronic expansion valve, its evaporation temperature is 5~10℃, serving as a stable cold source for battery thermal management, drive motor cooling, cabin refrigeration, refrigerated truck cargo compartment refrigeration, vehicle refrigerator, and vehicle computing chip heat dissipation.

3. The system according to claim 1, characterized in that, The turbine-boost coaxial unit has a minimum safe operating power threshold, which is not lower than the power corresponding to its surge boundary, and the power corresponding to the surge boundary is 10% to 30% of the rated power; the turbine-boost coaxial unit operates continuously and stably above the minimum safe operating power threshold, and does not stop due to changes in hot and cold loads; the turbine-boost coaxial unit operates at a speed of 20,000 to 40,000 r / min.

4. The system according to claim 1, characterized in that, In the steam turbine waste heat power generation module, the exhaust gas (350~450℃) from the turbine expansion section of the turbine-boost coaxial device is preheated and compressed by the preheater (65℃→200~350℃) and then enters the steam generator to generate superheated steam at 2~5MPa and 300~380℃, which drives a small steam turbine to generate electricity (3~8kW). The generated electricity is used to charge the battery pack. The exhaust steam from the steam turbine outlet is condensed by the condenser and returned to the steam generator, forming a closed Rankine cycle.

5. The system according to claim 1, characterized in that, The switching control strategy of the multi-battery pack switching management subsystem includes: when the state of charge (SOC) of the first battery pack is higher than 60%, the first battery pack supplies power and the second battery pack charges; when the SOC of the first battery pack drops to 20-30%, the switching control unit switches to the second battery pack for power supply within 20-100ms; after switching, the first battery pack is charged until its SOC recovers to 60-80% and this process is repeated cyclically; the third battery pack always maintains an SOC ≥90%; the total capacity of the first and second battery packs is 1 / 3 to 1 / 4 of the capacity of the power battery pack of a pure electric drive vehicle of the same level, and the specific value is determined by the vehicle's designed pure electric range and the transient power requirements of the drive; the capacity of the third battery pack meets the peak power requirements of the drive motor during emergency switching, preferably 2-10kWh.

6. The system according to claim 1, characterized in that, In the battery thermal management and fire protection subsystem: when the battery temperature is higher than 35℃ or the drive motor temperature is higher than the set threshold, the carbon dioxide direct cooling branch (5~10℃) is connected; when the battery temperature is lower than 5℃ or the drive motor temperature is lower than the set threshold, the carbon dioxide direct heating branch (40~50℃) is connected. When the battery temperature is in the range of 15~35℃, its direct cooling / heating branch is shut off. The drive motor branch starts and stops independently according to temperature requirements. The fire protection storage tank has a volume of 5~15L and a working pressure of 10~12MPa. When the battery temperature rise rate is ≥2℃ / s for 3 seconds, carbon dioxide is released and sprayed into the battery pack after being depressurized to 0.3~0.8MPa. The fire protection storage tank is switched with the main circulation loop through a gas replenishment branch via a three-way valve. Gas replenishment does not affect the normal circulation of the system and can be refilled.

7. The system according to claim 1, characterized in that, The clean fuel is selected from one or more of methanol, ethanol, dimethyl ether, biodiesel, and synthetic fuels, with methanol being preferred; the working fluid is supercritical carbon dioxide, and the closed thermodynamic cycle is a transcritical Brayton cycle; the turbine-boost coaxial device operates at a speed of 20,000~40,000 r / min.

8. The system according to claim 1, characterized in that, The high-pressure thermal compensation circuit is only activated in winter, and its working fluid flow rate is dynamically adjusted by the temperature control mode according to the heating load: the flow rate increases when the heating load increases and decreases when the heating load decreases; the high-pressure thermal compensation circuit and the low-pressure return gas pipe operate independently and do not interfere with each other.

9. The system according to claim 1, characterized in that, The vehicle control unit includes an energy management system (EMS), a battery management system (BMS), and a PID controller. The EMS is connected to the BMS via signals, and the PID controller is connected to the equivalent condensing pressure regulating unit via signals. The vehicle control unit is configured to output control signals to the switching control unit, the equivalent condensing pressure regulating unit, and the battery thermal management and fire suppression subsystem based on the battery pack state of charge, vehicle power requirements, and operating parameters of each subsystem.

10. A control method based on the system according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1 Start-up: Combustion chamber ignition, turbine-boost coaxial unit continuously operates at a power not lower than the minimum safe operating power threshold; fuel supply is adjusted by PID controller to maintain the compression section outlet pressure stable at 10~12MPa; recooler outlet is adjusted by temperature control mode to maintain the high pressure power tank temperature constant at 35℃. S2 regulates the recooler outlet pressure through a PID controller to lock the equivalent condensing pressure at 7.1MPa±0.1MPa; The exhaust waste heat from the turbine expansion section of the S3 turbine-boosting coaxial unit drives a steam turbine to generate electricity. The generated electricity can be used to charge the battery pack. The remaining waste heat is given priority to supply heat utilization needs such as heating, hot water, cooking, drying clothes, and defrosting. Excess heat that is not consumed after heat utilization is discharged into the atmosphere through an air cooler. S4 steam turbine generates electricity to charge the first battery pack, and the second battery pack discharges to drive the motor; When the heating and cooling loads increase, the waste heat used for power generation decreases and the power generation capacity automatically decreases; when the heating and cooling loads decrease, the waste heat used for power generation increases and the power generation capacity automatically increases. When the winter heat load is much greater than the cold load, the high-pressure heat compensation circuit will directly return the working fluid after heat exchange in the heat user branch to the intermediate stage of the compressor. S7 monitors the SOC of the first battery pack in real time. When it drops to 20-30%, the switching control unit switches to the second battery pack for power supply within 20-100ms. After switching to S8, the first battery pack is charged until the SOC is restored to 60-80%. S9 repeats S7~S8, with the two sets of batteries being charged and discharged alternately; When the first and second battery packs fail to switch or the power generation is abnormal, the third battery pack will switch in within ≤5ms. When the S11 battery temperature exceeds the limit, the carbon dioxide direct cooling / heating branch will be activated for regulation. In the event of thermal runaway, the carbon dioxide fire-fighting storage tank will automatically spray to extinguish the fire.

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