Vehicle power battery based on SOFC range extender and cabin thermal management system thereof

Abstract

The invention discloses a vehicle power battery based on an SOFC range extender and a cabin thermal management system of the vehicle power battery. According to the invention, the SOFC electric pile and the auxiliary engine system (BOP) are integrally and compactly arranged, so that the volume power density is obviously improved, and the SOFC electric pile is adaptive to a vehicle-mounted space. The system comprises four core subunits, namely a fuel supply and reforming unit, an air supply unit, an exhaust and waste heat recovery unit and a whole vehicle heat management unit. Innovatively, the whole vehicle heat management subunit intelligently distributes the recycled SOFC high-temperature exhaust waste heat to the battery heat preservation loop and the whole vehicle warm air loop according to needs through at least one four-way valve, and gradient utilization of energy is achieved. According to the method, the SOFC is controlled to continuously operate based on the average power demand, and frequent start and stop are avoided. The problems of mileage anxiety and low-temperature endurance attenuation of the pure electric vehicle are effectively solved, and meanwhile, a large-scale vehicle-mounted application scheme is provided for the SOFC technology.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and more specifically, to a vehicle power battery based on an SOFC range extender and its cabin thermal management system. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are highly efficient energy conversion devices that directly convert the chemical energy of fuel into electrical energy through electrochemical reactions, offering advantages such as high overall efficiency and wide fuel adaptability. Currently, SOFC power generation systems are mainly used in stationary power plants and other fixed locations. In these applications, a common approach is to separately encapsulate and partition the fuel cell stack and auxiliary systems (Balance of Plant, BOP). While this layout facilitates maintenance within a fixed location, it results in a loose overall system structure, significant wasted space, and low volumetric power density, making it difficult to meet the stringent compactness requirements of vehicle power systems.

[0003] Applying SOFC systems to vehicles as range extenders to charge the power battery is a promising development direction, but it faces numerous technical challenges. First, at the system integration level, the existing fixed SOFC layout concept cannot be directly transplanted into the limited installation space of a vehicle, lacking a highly integrated system architecture to simultaneously accommodate core components such as the fuel cell stack, vaporization-reformer, and heat exchanger. Second, at the energy management level, SOFCs operate at high temperatures (700~750℃), and their exhaust gases contain a large amount of high-quality waste heat. Current technologies typically fail to deeply couple this waste heat with the vehicle's overall thermal requirements. Especially in pure electric vehicles, winter heating relies entirely on the power battery's electrical energy, severely sacrificing the vehicle's driving range; simultaneously, the performance degradation of the power battery in low-temperature environments has not been addressed in an efficient and low-energy-consumption manner. Simply directly discharging the waste heat from a fixed SOFC would be a huge waste of the vehicle's overall energy efficiency.

[0004] Furthermore, in terms of control strategy, traditional fuel-powered range extenders typically start and stop frequently based on the instantaneous charge demand of the battery to adapt to dynamic power changes. However, due to its inherent characteristics, SOFC (Self-Powered Continuous Fuel Cell) systems experience slow start-stop processes, and frequent start-stop operations can severely damage their lifespan. Therefore, existing range extender control logic is not suitable for SOFC systems, necessitating the search for a new control paradigm based on the vehicle's average power demand that matches the long-term continuous operation characteristics of SOFC.

[0005] In summary, the existing technology lacks a compact SOFC range-extending power generation system for vehicles that integrates efficient thermal management and whose control logic matches the characteristics of SOFC, which hinders the application and promotion of SOFC technology in the vehicle field. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention provides a vehicle power battery and its cabin thermal management system based on an SOFC range extender. By integrating the battery stack and BOP into a single layout, the volumetric power density is improved. A four-way valve is used to intelligently distribute high-temperature waste heat, and the waste heat from the SOFC power generation system's exhaust gas is utilized to solve the problem of heat source for the power battery and cabin in low-temperature environments. This provides insulation for the battery and heating for the cabin, comprehensively improving the vehicle's energy efficiency and low-temperature range.

[0007] This invention provides a vehicle power battery based on an SOFC range extender and its cabin thermal management system, comprising: A solid oxide fuel cell stack, comprising a cathode, an anode, and an electrolyte, is used to generate direct current. The fuel supply and reforming subunit includes a fuel source and a vaporization-reformer connected in sequence by pipelines, wherein the outlet of the vaporization-reformer is connected to the inlet of the anode; An air supply subunit includes an air source and an air heat exchanger connected in sequence via pipelines, wherein the outlet of the air heat exchanger is connected to the inlet of the cathode; The exhaust gas and waste heat recovery subunit includes a burner and a waste heat recovery unit. The waste gas outlet of the anode and the waste gas outlet of the cathode are both connected to the inlet of the burner. The outlet of the burner is connected to the inlet of the heat exchanger and the inlet of the vaporization-reformer, respectively. The exhaust gas outlet of the heat exchanger and the exhaust gas outlet of the vaporization-reformer are both connected to the inlet of the waste heat recovery unit. The vehicle thermal management subunit includes a coolant circuit, a battery insulation circuit, a vehicle heating circuit, and at least one four-way valve, wherein the at least one four-way valve acts as a flow distributor and fluidly connects the coolant circuit, the battery insulation circuit, and the vehicle heating circuit.

[0008] Compared with existing technologies, this invention systematically solves the core challenges of SOFC in-vehicle applications through high integration and intelligent thermal management. First, by adopting an integrated layout of the fuel cell stack and BOP (Balance of Plant) system, it breaks through the limitations of traditional stationary power generation systems with zoned layouts, significantly improving volumetric power density and enabling the SOFC system to fit within the limited installation space of vehicles. Second, it innovatively designs a vehicle thermal management subunit including a four-way valve, achieving intelligent on-demand allocation of high-temperature exhaust waste heat from the SOFC. Furthermore, the system's operating strategy is deeply matched with the characteristics of the SOFC, enabling it to continuously and stably generate electricity based on the vehicle's average power demand, avoiding damage to the fuel cell stack from frequent start-stop cycles. Ultimately, this system not only extends vehicle range with a power generation efficiency exceeding 50%, but also elevates the overall energy efficiency of the vehicle to a new level through the cascade utilization of energy, providing key technical support for the large-scale application of SOFC technology in the vehicle field.

[0009] In one possible implementation, the fuel source consists of water and fuel. The unit uses a specific ratio of fuel and water as the fuel source. After being output from the fuel tank and water tank respectively, the fuel and water are first precisely metered according to a certain ratio using a mass flow meter to ensure material balance with the subsequent reforming reaction. The metered fuel and water then enter the vaporization-reformer.

[0010] In one possible implementation, a compressor is connected between the air source and the air heat exchanger, and a mass flow meter is connected between the fuel source and the vaporization-reformer.

[0011] Compared to existing technologies, this invention incorporates a compressor to ensure sufficient pressure and stable flow of air entering the fuel cell cathode, effectively overcoming the sensitivity of SOFC systems to fluctuations in intake conditions and providing an optimal gas source for the electrochemical reaction. Simultaneously, the inclusion of a mass flow meter enables precise fuel metering and closed-loop control, ensuring material balance between the reforming and anode reactions and preventing fuel waste or uneven reaction. The synergistic operation of these two components lays the foundation for stable, efficient, and reliable system operation in high-vibration on-board environments.

[0012] In one possible implementation, the coolant circuit includes a water pump, the coolant side of a waste heat recovery unit, a radiator, and an expansion tank connected in sequence via pipelines.

[0013] The system comprises a water pump driving the coolant to circulate within the coolant circuit; an expansion tank to contain the coolant as its volume changes due to thermal expansion and contraction, and to provide pressure stabilization and gas separation for the circuit. More specifically, the coolant circuit design, through the coordinated operation of its components, constructs a stable and efficient heat transfer and management system. The water pump drives the coolant circulation, ensuring timely heat transfer; the coolant flowing through the waste heat recovery unit efficiently captures waste heat from the system; the radiator ensures effective dissipation when there is excess heat; and the expansion tank provides pressure stabilization and volume compensation for the closed circuit. The entire circuit collectively ensures that the SOFC system and its associated components always operate within a safe and efficient temperature range.

[0014] In one possible implementation, the at least one four-way valve is configured to have three operating modes, enabling on-demand heat distribution by switching flow paths: In the first working mode, the high-temperature coolant flowing out of the waste heat recovery unit is guided to flow sequentially through the vehicle heating circuit and the battery insulation circuit to provide heat for the cabin heating and the power battery heating. In the second operating mode, the high-temperature coolant is guided to flow through the radiator to dissipate excess heat from the system into the atmosphere; In the third operating mode, the path to the vehicle's heating circuit is cut off, and most of the coolant is guided to flow through the radiator to achieve full system heat dissipation.

[0015] Compared to existing technologies, this invention, through the configuration of multiple operating modes of the four-way valve, achieves intelligent and dynamic management of the high-temperature coolant flow path. Its core advantage lies in its ability to flexibly and precisely distribute waste heat to different terminals such as heating, battery insulation, or heat dissipation based on the vehicle's real-time heat demand. This prioritizes passenger comfort and battery activity in cold weather, while ensuring system heat dissipation safety under high-temperature or high-load conditions. This on-demand allocation mechanism completely changes the traditional system's singular or wasteful heat utilization, systematically improving the vehicle's energy efficiency and environmental adaptability.

[0016] In one possible implementation, the first operating mode is executed when the ambient temperature is below a first threshold and the power battery temperature is below the optimal operating range. When the ambient temperature is within a comfortable range and the system's heat generation exceeds the vehicle's heat demand, the second operating mode is executed. When the ambient temperature is higher than the second threshold or the solid oxide fuel cell stack is in a high-power operating state, the third operating mode is executed.

[0017] The advantage of this control strategy lies in achieving full automation and intelligence in system thermal management. By collaboratively judging multiple parameters such as ambient temperature, battery status, and system load, the system can autonomously select the optimal thermal management strategy. Without manual intervention, it can maintain the temperature of each component within the optimal operating range while ensuring battery activity and passenger comfort, effectively improving system reliability, adaptability, and the energy utilization efficiency of the entire vehicle.

[0018] A second objective of this invention is to provide an energy management method for vehicles, applied to the aforementioned SOFC-based vehicle power battery and its cabin thermal management system, the method comprising: S1. Control the solid oxide fuel cell stack to operate continuously based on the vehicle's average power demand to charge the power battery until the power battery reaches a preset upper limit and then enters standby mode. S2. Recover the high-temperature exhaust waste heat generated during the operation of the solid oxide fuel cell stack and transfer it to the coolant circuit of the vehicle thermal management subsystem. S3. By controlling the four-way valve, the heat in the coolant circuit is distributed as needed to the battery insulation circuit and / or the vehicle heating circuit.

[0019] This energy management method achieves global energy optimization by systematically integrating the continuous power generation characteristics of SOFC, high-temperature waste heat recovery, and the vehicle's thermal requirements. Its advantages lie in two aspects: firstly, ensuring that SOFC always operates at high efficiency and avoiding damage from frequent start-stop cycles; and secondly, intelligently allocating heat to transform waste heat from power generation into effective resources that guarantee battery performance and passenger comfort. This achieves the comprehensive goals of extending driving range, improving energy efficiency, and enhancing reliability at the system level.

[0020] The third objective of this invention is to provide a vehicle comprising the aforementioned SOFC-based range extender-powered vehicle battery and its cabin thermal management system. Vehicles equipped with this system successfully integrate efficient power generation with intelligent thermal management, fundamentally expanding the practical applications of electric vehicles. It not only completely eliminates range anxiety associated with pure electric vehicles by utilizing natural gas fuel, but also overcomes industry challenges such as reduced range in winter and battery performance degradation at low temperatures through a unique waste heat recovery system. This enables the vehicle to demonstrate excellent adaptability and economy in cold-region operations and long-distance transportation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the vehicle power battery and its cabin thermal management system based on the SOFC range extender of the present invention. Detailed Implementation

[0022] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the present invention.

[0023] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can fully understand the technical essence and beneficial effects of the present invention.

[0026] Figure 1 This invention can be used to understand the vehicle power battery based on the SOFC range extender and its cabin thermal management system.

[0027] I. System Composition and Workflow The core of this system lies in the high degree of integration between high-efficiency SOFC power generation and intelligent thermal management of the entire vehicle. For example... Figure 1 As shown, the system mainly consists of the following sub-units working together: 1. Fuel Supply and Reforming Subunit This unit uses a specific ratio of fuel and water as fuel sources. After being output from the fuel tank and water tank respectively, the fuel and water are first precisely metered by mass flow meters to ensure material balance with the subsequent reforming reaction. The metered fuel and water then enter the vaporization-reformer. Here, the fuel and water are vaporized and undergo a reforming reaction under the action of a catalyst, producing hydrogen-rich reformed gas, primarily composed of carbon monoxide. This reformed gas is then transported to the anode of the SOFC stack.

[0028] 2. Water Management and Supply Subunit This unit recovers and processes the water condensed from the exhaust gas in the exhaust gas and waste heat recovery subunit, and uses it as a water source to meet the water vapor required for fuel reforming in the fuel supply and reforming subsystem unit. 3. Air Supply Subunit After being filtered, the ambient air is compressed and pressurized by an air compressor. The pressurized air flows into an air heat exchanger, where it exchanges heat with the high-temperature flue gas from the burner and is preheated to the temperature required for the fuel cell stack to operate. The preheated air is then sent to the cathode of the SOFC fuel cell stack.

[0029] 4. SOFC fuel cell stack electron generation unit Hydrogen-rich fuel supplied to the anode and oxygen (from air) supplied to the cathode undergo an electrochemical reaction inside the fuel cell stack, directly generating direct current (DC) electricity. The generated electricity is used to charge the vehicle's battery via a power conversion device (such as a DC / C converter) or to directly drive the electric motor. Simultaneously, the electrochemical reaction releases a large amount of heat, maintaining the fuel cell stack at a high operating temperature of 700–750°C.

[0030] 5. Exhaust and Waste Heat Recovery Subunit The unreacted residual gases (containing unexploded fuel and remaining oxygen) exiting from the anode and cathode of the fuel cell stack are collected in the burner for complete combustion, releasing all remaining chemical energy and producing higher-temperature flue gas. This high-temperature flue gas is utilized as a high-quality heat source as described below: It flows through the vaporization-reformer, providing the necessary heat for the strong endothermic reforming reaction that is continuously taking place inside.

[0031] The air flowing through the air heat exchanger is preheated before entering the fuel cell stack, improving the overall efficiency of the system.

[0032] Finally, the exhaust gas, whose temperature has dropped significantly but is still usable, enters the waste heat recovery unit, where its residual heat is transferred to the coolant flowing through it.

[0033] 6. Vehicle Thermal Management Subunit This unit is crucial for achieving comprehensive energy utilization, and its core components are two four-way valves. A coolant circuit driven by a water pump flows through a waste heat recovery unit, absorbing the exhaust waste heat and becoming high-temperature coolant. The four-way valves, acting as intelligent flow distributors, can allocate the high-temperature coolant to the following paths as needed based on real-time operating conditions: First operating mode (low temperature condition): When the ambient temperature is low and cabin heating or battery heating is required, the four-way valve switches the flow path, guiding the high-temperature coolant to flow sequentially through the vehicle's heating circuit and battery insulation circuit. The coolant first provides warm air to the passenger compartment, and then heats the power battery, ensuring it is at its optimal operating temperature, effectively solving the problem of reduced range in electric vehicles during winter.

[0034] Second operating mode (normal temperature or medium load): When the system generates more heat than the vehicle’s heat demand, the four-way valve guides most of the coolant to flow through the radiator, and the excess heat is dissipated into the atmosphere by the cooling fan to maintain the system temperature stability.

[0035] The third operating mode (high temperature or high load): When the ambient temperature is extremely high or the fuel cell stack is operating at high power, the four-way valve can cut off the path to the heating circuit, guiding most or even all of the coolant to flow through the radiator, ensuring that the system dissipates heat at full capacity and preventing overheating.

[0036] The expansion tank in the coolant circuit is used to contain the coolant that expands and contracts due to temperature changes, and to provide a stable pressure environment for the circuit.

[0037] II. Control Strategies and Energy Management Methods The energy management method of the present invention is executed by a system controller, and its core logic includes: Power generation control: The SOFC stack is controlled to operate continuously and stably based on the vehicle's average power demand, serving as the primary power source for charging the power battery. It only enters standby mode when the power battery charge reaches a preset high limit and restarts when the charge falls below a preset low limit, avoiding frequent start-stop cycles for instantaneous power demands and significantly extending the lifespan of the SOFC stack.

[0038] Thermal management control: The system monitors ambient temperature, battery temperature, and system load in real time. Through preset temperature thresholds (such as the first threshold and the second threshold) and logical judgment, it automatically selects and executes the corresponding working mode of the four-way valve to achieve fully automatic, intelligent, and on-demand heat distribution.

[0039] Compared with existing technologies, this specific implementation method systematically solves the core challenges of SOFC vehicle-mounted application through the aforementioned highly integrated system architecture and intelligent control strategy. The resulting benefits are significant: Space and efficiency: The integrated layout of the fuel cell stack and BOP significantly improves the volumetric power density, enabling SOFC systems to be adapted to vehicle space.

[0040] Range and performance: Over 50% power generation efficiency directly extends range; innovative thermal management converts waste heat into heat sources for battery insulation and cabin heating, overcoming the performance bottleneck of electric vehicles in winter.

[0041] Reliability and economy: The stable operation strategy avoids stack damage; the use of natural gas fuel reduces operating costs and finds a large-scale vehicle application scenario for SOFC technology.

[0042] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A SOFC range extender based vehicle power battery and its cabin thermal management system, characterized in that, Comprising: a solid oxide fuel cell stack for generating direct current, comprising a cathode, an anode and an electrolyte; a fuel supply and reforming subunit, comprising a fuel source and a vaporization-reformer connected in sequence by pipes, the outlet of the vaporization-reformer being in communication with the inlet of the anode; an air supply subunit, comprising an air source and an air heat exchanger connected in sequence by pipes, the outlet of the air heat exchanger being in communication with the inlet of the cathode; an exhaust and waste heat recovery subunit, comprising a combustor and a waste heat recovery device, the exhaust outlet of the anode and the exhaust outlet of the cathode being in communication with the inlet of the combustor, the outlet of the combustor being in communication with the inlet of the heat exchanger and the inlet of the vaporization-reformer respectively, the exhaust outlet of the heat exchanger and the exhaust outlet of the vaporization-reformer being in communication with the inlet of the waste heat recovery device; a vehicle thermal management subunit, comprising a coolant loop, a battery thermal insulation loop, a vehicle cabin heating loop and at least one four-way valve, wherein the at least one four-way valve is fluidly connected to the coolant loop, the battery thermal insulation loop and the vehicle cabin heating loop as a flow distributor.

2. The SOFC ranger based vehicle power battery and its cabin thermal management system of claim 1, wherein, The fuel source is composed of water and fuel.

3. The SOFC ranger based vehicle power battery and its cabin thermal management system of claim 1, wherein, A compressor is connected between the air source and the air heat exchanger, and a mass flow meter is connected between the fuel source and the vaporization-reformer.

4. The SOFC ranger based vehicle power battery and its cabin thermal management system of claim 1, wherein, The coolant loop comprises a water pump, a coolant side of the waste heat recovery device, a radiator and an expansion tank connected in sequence by pipes.

5. The SOFC ranger based vehicle power battery and its cabin thermal management system of claim 1, wherein, The at least one four-way valve is configured to have three working modes, and the heat is distributed on demand by switching the flow path: In the first working mode, the high-temperature coolant flowing out of the waste heat recovery device is guided to flow through the vehicle cabin heating loop and the battery thermal insulation loop in sequence, providing heat for cabin heating and power battery heating; In the second working mode, the high-temperature coolant is guided to flow through the radiator, dissipating excess heat into the atmosphere; In the third working mode, the path to the vehicle cabin heating loop is cut off, and most of the coolant is guided to flow through the radiator to achieve full-power heat dissipation.

6. The SOFC range extender based vehicle power battery and its cabin thermal management system according to claim 5, wherein: the first working mode is executed when the ambient temperature is lower than a first threshold and the power battery temperature is lower than the optimal working range; the second working mode is executed when the ambient temperature is in a comfortable range and the system heat production is greater than the vehicle heat demand; the third working mode is executed when the ambient temperature is higher than a second threshold or the solid oxide fuel cell stack is in a high-power operating state.

7. An energy management method for a vehicle, characterized by, The management method applied to the SOFC range extender based vehicle power battery and its cabin thermal management system according to any one of claims 1-6, comprising: S1, controlling the solid oxide fuel cell stack to operate continuously based on the average power demand of the vehicle, charging the power battery until the power battery reaches a preset upper limit, and then entering a standby state; S2, recovering the high-temperature exhaust waste heat generated during the operation of the solid oxide fuel cell stack and transferring it to the coolant loop of the vehicle thermal management subsystem; S3. Distribute the heat in the cooling liquid circuit to the battery thermal insulation circuit and / or the vehicle heating circuit on demand by controlling the four-way valve.

8. A vehicle characterized by comprising: A vehicle power battery based on SOFC range extender and a cabin thermal management system thereof, comprising the SOFC range extender as claimed in any one of claims 1-6.

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