CN100547837C - Fuel cell system for portable device and method of operation thereof - Google Patents

Abstract

A fuel cell system for a portable device, the portable device has a heat-generating component, and the fuel cell system includes: a fuel cell body, wherein fuel undergoes a chemical reaction to provide electrical energy, and the resulting reaction product includes water; fuel supply and The circulation driving device is used to control the fuel quantity and/or the fuel flow rate in the fuel circulation circuit according to the fuel concentration and/or the fuel temperature; the water circulation driving device is used to control the water quantity in the water circulation circuit according to the fuel temperature and the temperature of the heat-generating components and/or water flow rate; fuel circulation loop, which constitutes the circuit between the fuel cell main body and the fuel supply and circulation drive unit, through which fuel is supplied to the fuel cell main body and the remaining fuel is returned to the fuel supply and circulation drive unit; water circulation a loop constituting a loop in which water in the reaction product flows; and a double-cycle heat exchange unit in which heat exchange occurs between the fuel circulation loop, the water circulation loop, and the heat-generating component.

Description

Fuel cell system for portable device and method of operation thereof

technical field

The present invention relates to a fuel cell system for portable equipment, and more particularly, to a fuel cell system with primary and secondary circulation loops and dual circulation heat exchange units and its operating method.

Background technique

With the vigorous development of information technology, the functions of portable electronic devices are becoming more and more powerful, and the power consumption increases accordingly. In order to meet a certain use time, the demand for energy of portable devices is also increasing. However, in order to reflect the portability, the volume of portable devices has great limitations, and people always hope that the smaller the volume, the better. Therefore, the contradiction between the function, time, volume and energy of portable devices is a very real problem. At present, lithium secondary batteries are widely used in portable devices. Since the performance indicators of lithium secondary batteries are close to the theoretical upper limit, relying on the development of lithium secondary battery technology cannot effectively solve the above problems.

Fuel cells have the characteristics of high energy density, high conversion efficiency, and no pollution. In recent years, people have paid more and more attention to using them to replace lithium secondary batteries as power sources for portable devices. At present, there are two types of fuel cells suitable for portable devices: direct methanol fuel cells and methanol modified fuel cells. The overall chemical reaction equations of these two fuel cells are as follows:

The fuel cell itself is a relatively complex power generation system, which has a fuel storage device, a fuel supply and control device, a core power generation device, a starting power device, a system management device, and a product processing device. With the current state of technology, a typical system logic block diagram of direct alcohol fuel cell is shown in Figure 1.

In FIG. 1 , a fuel storage unit 100 is connected to a fuel supply unit 101 through a fuel delivery pipeline, and the fuel supply unit 101 is connected to a fuel cell stack 105 through a fuel delivery pipeline. The fuel supply unit 101 provides transmission power to input the fuel in the fuel storage unit 100 into the fuel stage of the fuel cell stack 105 . After the fuel residual liquid discharged from the fuel stage of the fuel cell stack 105 passes through the gas-liquid separation unit 106, the exhaust gas is transported to the exhaust gas treatment/discharge unit 107, and the low-concentration fuel (unburned methanol is mixed with the reaction product water, which reduces the fuel's concentration) Concentration) is then returned to the fuel supply unit 101 through the pipeline. On the delivery pipeline between the fuel supply unit 101 and the fuel cell stack 105, there is a fuel concentration monitoring unit 102 connected in series, which is connected with the fuel cell control/transformation/serving unit 104 through a data signal line. The fuel cell control/conversion/serving unit 104 is connected to the fuel supply unit 101 with a control signal line. The fuel cell control/conversion/serving unit 104 obtains the fuel concentration value delivered to the fuel cell stack 105 through the concentration sensor of the fuel concentration monitoring unit 102, and sends a control signal to the fuel supply unit 101 through logical judgment, and the fuel supply unit 101 adjusts the The fuel delivered to the fuel cell stack 105 is maintained within a certain concentration range.

The air supply unit 109 is connected to the air stage of the fuel cell stack 105 through an air transmission pipe, and is connected to the fuel cell control/conversion/serving unit 104 with a control signal line. The air supply unit 109 provides power for conveying air and receives a control signal from the fuel cell control/conversion/serving unit 104 to control the flow of air delivered to the fuel cell stack 105 . The tail gas discharged from the air stage of the fuel cell stack 105 passes through the condensation/gas-liquid separation unit 108 for gas-liquid separation, the waste gas is sent to the tail gas treatment/discharge unit 107 for treatment and discharge, and the separated water is sent to the fuel supply unit through the delivery pipeline 101 to adjust the concentration of fuel. The condensation/gas-liquid separation unit 108 has a control signal line connected to the fuel cell control/conversion/serving unit 104. The fuel cell control/conversion/serving unit 104 sends a control signal to the condensation/gas-liquid separation unit 108 to control the amount of separated water.

The starting power supply 103 provides starting energy for the fuel cell stack 105 through the control of the fuel cell control/conversion/serving unit 104 . When the fuel cell stack 105 is normally generating power, the fuel cell control/conversion/serving unit 104 can charge the starting power supply 103 .

The electric energy generated by the fuel cell stack 105 is processed by the fuel cell control/conversion/serving unit 104 and then output. A data signal line is connected between the fuel cell control/conversion/serving unit 104 and the fuel cell stack 105, and the fuel cell control/conversion/serving unit 104 monitors the fuel cell stack 105 through the sensor in the fuel cell stack 105. working status.

The fuel cell stack 105 is composed of several power generating units, and the overall chemical reaction equation of fuel cell power generation is:

At present, fuel cells are used in portable devices such as notebook computers. Strictly speaking, the fuel cell still exists as an independent component, that is, the fuel cell and the notebook computer are basically structurally "matched" (corresponding interface connection between), functionally speaking, the demarcation is very clear. In doing so, not only will the volume of the entire system be difficult to reduce, but also the entire (notebook computer + fuel cell) system components are redundant, and the ability of each functional component is not fully utilized. In fact, if the fuel cell "system" and the notebook computer "system" are organically integrated, making full use of their respective characteristics, making full use of their strengths and circumventing weaknesses, and giving full play to the capabilities of each functional component, the entire system can be effectively optimized and the fuel cell can be used in portable devices. application.

Chinese invention patent application "fuel cell, equipment, portable computer and method for driving fuel cell" (publication number: CN 1647305A, application number: 03808411.2) discloses the following content: Utilize the supply fuel of fuel cell to absorb the heating components such as notebook computer CPU The heat can increase the fuel temperature of the fuel cell while reducing the temperature of the heat-generating components of the portable device, thereby increasing the reaction efficiency of the fuel cell. Although this invention utilizes the characteristics of the liquid fuel cycle of the fuel cell, it proposes a method to solve the cooling of the portable equipment to a certain extent. However, this invention does not give full play to the characteristics of liquid circulation in the fuel cell "system", and the technical solution has the following technical defects:

1. This invention only utilizes the front-end methanol aqueous solution fuel supply line of the fuel cell to form a cooling circuit. The recycling of fuel cell reaction product water is not utilized. In fact, the specific heat capacity of water is greater than that of aqueous methanol. (The specific heat capacity of water is 4.19c/KJ.kg ^-1 k ^-1 , the specific heat capacity of methanol is 2.50c/KJ.kg ^-1 k ^-1 )

2, the fuel that this technical scheme uses is methanol aqueous solution. The boiling point of pure methanol is 64.7°C, so it cannot be applied to this technical solution for pure methanol fuel. Because vaporized pure methanol can cause safety hazards in closed liquid circulation lines. Since pure methanol cannot be used, the effective energy density of this scheme is low, and the available energy is low using the same fuel tank.

3. Due to the fact that portable devices, such as notebook computers, actually generate a lot of heat, this technical solution only relies on a single liquid circulation method of the front-end fuel supply line, which is difficult to effectively cool the heat-generating components and improve the efficiency of the fuel cell at the same time.

4. The fuel temperature control method of this technical solution only relies on flow control, and the method is single. Once the maximum flow rate cannot effectively prevent the fuel temperature from rising, the temperature of the fuel cell power generation body will be uncontrollable, which will reduce the efficiency of the fuel cell and even shorten the life of the fuel cell.

Fig. 2 has shown the system block diagram of Chinese invention patent application CN 1647305A, and this scheme just connects the heat exchange unit 202 in series on the fuel delivery pipeline between the fuel supply/flow adjustment unit 201 and the fuel cell group 206, by the heat exchange unit 202 (located in the vicinity of heat-generating components such as CPU, etc.) the passing fuel is heated by the heat emitted by the heat-generating components, and then delivered to 206 . And did not utilize back-end reaction product water.

The U.S. patent "Portable electronic device powered by protonexchange membrane fuel cell Patent No.US 6447945" provides a technical solution for a notebook computer powered by a fuel cell, which describes a treatment solution for fuel cell by-product water. When the water channel is arranged, the part of the water channel placed behind the display can help the display screen to dissipate heat. The patent focuses on how to treat water. However, a solution cannot be proposed for the system heat dissipation optimization of the fuel cell system and the notebook computer system.

Chinese invention patent application "a cooling device for electrical appliances" (CN01807323.9), and its American patent application "Cooling system, especially for electrical appliances" (US2003141038), the invention utilizes the physical state change of fuel in the fuel supply circuit , such as (the thermodynamic endothermic process of compressing liquid hydrogen into hydrogen) as heat absorption to achieve the purpose of heat dissipation. In practice, this kind of physical state change is difficult to apply, especially for portable equipment, which has poor usability, such as the need to carry compressed liquid hydrogen. In addition, this technical solution does not effectively utilize the reaction product water.

The U.S. invention patent application "System to remove heat and water from afuel cell powered device" (US20030096144) proposes a method of collecting the reaction product water and transporting it to the heating part, where there are sponges and other water-absorbing materials. The water in the water-absorbing material volatilizes and absorbs heat naturally to achieve the purpose of heat dissipation, and the heat dissipation can be accelerated by a fan. This scheme does not effectively reuse the product water, but directly volatilizes it, which is only a treatment for heat dissipation, which is a waste of resources.

Contents of the invention

According to an aspect of the present invention, there is proposed a fuel cell system for a portable device having a heat-generating component, the fuel cell system includes: a fuel cell body in which fuel undergoes chemical Reaction, providing electrical energy, and the generated reaction products include water; fuel supply and circulation driving device, used to control the fuel amount and/or fuel flow rate in the fuel circulation circuit according to the fuel concentration and/or fuel temperature in the fuel circulation circuit; The water circulation driving device is used to control the water volume and/or water flow rate in the water circulation circuit according to the fuel temperature in the fuel circulation circuit and the temperature of the heat-generating components; the fuel circulation circuit constitutes the gap between the fuel cell main body and the fuel supply and circulation drive device A circuit through which fuel is supplied to the main body of the fuel cell, and the remaining fuel that has not undergone chemical reactions is sent back to the fuel supply and circulation drive device; the water circulation circuit constitutes the circuit in which the water in the reaction product flows; and the double cycle heat An exchange unit, in the double cycle heat exchange unit, heat exchange occurs between the fuel circulation circuit, the water circulation circuit and the heat generating components.

Preferably, the fuel cell system for portable equipment further includes an auxiliary cooling device for cooling the water circulation circuit according to the water volume and/or water flow rate in the water circulation circuit and the fuel temperature in the fuel circulation circuit.

Preferably, the fuel cell system for portable equipment further includes a water collection and supply device for collecting reaction product water, and according to the water temperature in the water circulation loop, supplementing water with a temperature lower than that of the water in the water circulation loop Reaction product water, and drain excess water from the water recirculation loop. More preferably, the water collection and supply device also provides water to the fuel supply and circulation drive device according to the instructions of the fuel supply and circulation drive device; the fuel supply and circulation drive device utilizes the water collection and circulation drive device The water supplied by the supply means adjusts the concentration of the fuel supplied to the fuel cell main body.

Preferably, the fuel cell system for portable equipment further includes an unreacted fuel collection device, which is used to separate the remaining fuel that has not undergone chemical reactions and reaction products, and send the remaining fuel into the fuel circulation loop, and return it to the fuel supply and Cycle drive.

Preferably, the fuel cell system for portable equipment further includes a fuel storage device for storing high-purity fuel.

Preferably, the heat generating component is at least one of the central processing unit, memory, image processor and display of the portable device.

Preferably, the fuel is methanol.

According to another aspect of the present invention, a method for operating the above-mentioned fuel cell system is proposed, including the following steps: start the fuel supply and circulation driving device, so as to make the fuel circulation circuit run; determine whether the temperature rise of the fuel has reached the first threshold; When the temperature rise reaches the first threshold, start the water circulation driving device, so as to make the water circulation loop run; judge whether the fuel temperature has exceeded the second threshold; when the fuel temperature has exceeded the second threshold, judge whether the temperature of the heating component exceeds the third threshold; When the temperature of the heat-generating component does not exceed the third threshold, the water circulation driving device is driven to increase the flow in the water circulation loop, and the step of judging the fuel temperature is returned.

Preferably, the operating method of the fuel cell system further includes the step of: stopping the auxiliary cooling device when the fuel temperature does not exceed the second threshold.

Preferably, the operating method of the fuel cell system further includes the step of: when the temperature of the heat-generating component exceeds the third threshold, judging whether the flow in the water circulation loop has reached the maximum value; if the flow in the water circulation loop has reached the maximum value, Then start the auxiliary cooling device.

Preferably, the operation method of the fuel cell system further includes the step of: if the flow rate in the water circulation loop does not reach the maximum value, then drive the water circulation driving device, thereby increasing the flow rate in the water circulation loop, and returning to the temperature of the heat-generating components. Judgment steps.

Preferably, the operating method of the fuel cell system further includes the step of: judging in parallel with the above steps whether the fuel concentration in the fuel circulation loop is within a pre-specified range; if the fuel concentration exceeds the upper limit of the pre-specified range, Water is provided to the fuel supply and circulation driving device for dilution to reduce the fuel concentration; if the fuel concentration is lower than the lower limit of the pre-specified range, the fuel supply and circulation driving device increases the fuel concentration.

Preferably, the operating method of the fuel cell system further includes the step of: judging whether an instruction to shut down the fuel cell system is received in parallel with the above steps; and shutting down the fuel cell system when the instruction to shut down the fuel cell is received.

Description of drawings

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

Figure 1 shows a typical system logic block diagram of a direct alcohol fuel cell.

Fig. 2 shows the system block diagram of Chinese invention patent application CN 1647305A.

3A and 3B respectively show a simplified system block diagram and a specific system block diagram of the fuel cell system according to the present invention.

Figure 4 shows a schematic (three-view) view of a dual cycle heat exchange component used in the present invention.

FIG. 5 shows the detailed operation flow of the fuel cell system at various stages according to the present invention.

Detailed ways

The specific implementation manner of the present invention will be described below in conjunction with the accompanying drawings. It should be noted that the described embodiments are for the purpose of illustration only, and do not limit the scope of the present invention. The various numerical values described are not intended to limit the present invention, and these numerical values can be appropriately modified according to the needs of those of ordinary skill in the art.

The technical scheme proposed by the present invention can effectively utilize the front-end fuel supply circuit of the direct alcohol fuel cell and the recovery circuit of the rear-end reaction product water, not only can use pure methanol as fuel, which improves the effective energy density, but also can cool the water by constructing a liquid double cycle The circuit uses water as the coolant of the main cooling circuit and fuel (such as methanol) as the coolant of the auxiliary cooling circuit. While effectively cooling the heat-generating components of portable devices, the concentration of the fuel aqueous solution is reasonably proportioned and the fuel temperature can be accurately controlled. , at an ideal temperature, it is input into the power generation part of the fuel cell, so that the fuel cell can achieve the best reaction efficiency.

3A and 3B respectively show a simplified system block diagram and a specific system block diagram of the fuel cell system according to the present invention.

3A and FIG. 3B are described in detail below. In FIG. 3A and FIG. 3B , the same components are denoted by the same reference symbols and described uniformly to avoid repetition.

The fuel storage unit 300 is connected to the fuel supply and concentration control unit 301 through the fuel delivery pipeline, the fuel supply and concentration control unit 301 is connected to the double cycle heat exchange unit 303 through the fuel transmission pipeline, and the double cycle heat exchange unit 303 is connected to the heating element of the portable device. Where the parts are closely connected, the heat of the heat-generating parts is transferred through heat conduction. The fuel powered by the fuel supply and concentration control unit 301 and transmitted to the double-cycle heat exchange unit 303 passes through the upper internal channel of the double-cycle heat exchange unit 303 to absorb the heat conducted by the heat-generating components, and then passes through the fuel transmission pipeline and the fuel temperature monitoring unit 302 , delivered to the fuel stage of the fuel cell stack 307. After the reacted fuel residual liquid discharged from the fuel stage of the fuel cell stack 307 passes through the gas-liquid separation unit 308, the exhaust gas is transported to the tail gas treatment/discharge unit 307, and the low-concentration fuel (unburned methanol is mixed with the reaction product water, reduce the concentration of the fuel) then return to the fuel supply and concentration control unit 301 through the fuel delivery pipe. On the fuel delivery pipeline between the double cycle heat exchange unit 303 and the fuel cell stack 307, there is a fuel temperature monitoring unit 302 connected in series with the fuel cell control/conversion/serving unit 306 through a data signal line. The fuel cell control/conversion/serving unit 306 is connected with the fuel supply and concentration control unit 301 by a control signal line. The fuel cell control/conversion/serving unit 306 obtains the fuel temperature value delivered to the fuel cell stack 307 through the temperature sensor of the fuel temperature monitoring unit 302 . The fuel cell control/conversion/serving unit 306 obtains the fuel concentration value delivered to the fuel cell stack 307 through the concentration sensor of the fuel supply and concentration control unit 301 . Through logical judgment, a control signal is sent to the fuel supply and concentration control unit 301, and the fuel supply and concentration control unit 301 adjusts the fuel delivered to the fuel cell stack 307 to maintain within a certain concentration range.

The air supply unit 313 is connected to the air stage of the fuel cell stack 307 through an air transmission pipe, and is connected to the fuel cell control/conversion/serving unit 306 with a control signal line. The air supply unit 313 provides power for conveying air and receives a control signal from the fuel cell control/conversion/serving unit 306 to control the flow of air delivered to the fuel cell stack 307 . The tail gas discharged from the air stage of the fuel cell stack 307 passes through the condensation/gas-liquid separation unit 310 for gas-liquid separation, the waste gas is sent to the tail gas treatment/discharge unit 309 for treatment and discharge, and the separated water is sent to the water collection/ monitoring unit 304 . The water collection/monitoring unit 304 is connected to the fuel cell control/conversion/serving unit 306 by a control signal line, and receives the control signal from the fuel cell control/conversion/serving unit 306 . There is a water delivery pipeline between the water collection/monitoring unit 304 and the fuel supply and concentration control unit 301, and the water collection/monitoring unit 304 serves as fuel supply and concentration control unit 301 by receiving the control signal from the fuel cell control/conversion/serving unit 306. Add water.

A closed main water circulation loop is formed by the main water circulation drive unit 312 , the auxiliary cooling unit 311 and the double circulation heat exchange unit 303 . The circulation power is provided by the water main circulation drive unit 312, and the water circulation pipe passes through the auxiliary heat dissipation unit 311, then flows through the lower internal channel of the double circulation heat exchange unit 303 to absorb the heat conducted by the heat-generating components, and then flows back to the water main circulation drive unit 312 . Between the double cycle heat exchange unit 303 and the water main cycle drive unit 312 , the water collection/monitoring unit 304 can supplement water to the water main cycle circuit by receiving the control signal from the fuel cell control/conversion/serving unit 306 . The main water circulation driving unit 312 , the auxiliary cooling unit 311 and the double circulation heat exchange unit 303 are respectively connected to the fuel cell control/conversion/serving unit 306 by control lines. The main water circulation driving unit 312 adjusts the flow of the main water circulation loop by receiving the control signal from the fuel cell control/conversion/serving unit 306 . The auxiliary cooling unit 311 determines whether to perform auxiliary cooling by receiving a control signal from the fuel cell control/conversion/serving unit 306 . The fuel cell control/conversion/serving unit 306 obtains the temperature value of the heat-generating components of the portable device and the temperature value of the water in the main water circulation loop through the temperature sensor in the auxiliary heat dissipation unit 311 and the double-circulation heat exchange unit 303 .

The fuel cell control/conversion/serving unit 306 adjusts the flow of fuel and water according to the obtained fuel temperature, the temperature of the heat-generating components of the portable device, and the temperature of the water in the main water circulation circuit, and decides whether to turn on the auxiliary heat dissipation.

The condensation/gas-liquid separation unit 310 has a control signal line connected to the fuel cell control/conversion/serving unit 306 . The fuel cell control/conversion/serving unit 306 sends a control signal to the condensation/gas-liquid separation unit 310 to control the amount of water separated by the condensation/gas-liquid separation unit 310 .

The starting power supply 305 provides starting energy for the fuel cell stack 307 through the control of the fuel cell control/conversion/serving unit 306 . When the fuel cell stack 307 is generating electricity normally, the starting power supply 305 can be charged by the fuel cell control/conversion/serving unit 306 as needed.

The electric energy generated by the fuel cell stack 307 is processed by the fuel cell control/conversion/serving unit 306 and then output. A data signal line is connected between the fuel cell control/conversion/serving unit 306 and the fuel cell stack 307, and the fuel cell control/conversion/serving unit 306 monitors the fuel cell stack 307 through the sensor in the fuel cell stack 307. working status.

Although a separate control unit (fuel cell control/transformation/serving unit) is shown in Figures 3A and 3B, those skilled in the art can implement various control functions in individual modules according to actual needs. The discrete units shown here can be combined or further disassembled as required. These individual/collective units should also be included within the scope of the present invention.

Figure 4 shows a schematic (three-view) view of a dual cycle heat exchange component used in the present invention.

As shown in the figure, the dual cycle heat exchange component includes a housing 400 , a first inlet 401 , a second inlet 403 , a first outlet 402 and a second outlet 404 . The structure of the pipe is a serpentine pipe with a circular or square cross-section, and is divided into two pipes, the upper and the lower. The inlet 401 corresponds to the outlet 402 , and the inlet 403 corresponds to the outlet 404 . Each pipeline is directly connected in series with the fuel supply circuit and the product water circuit respectively.

Since the heat exchanging component 400 is a metal heat-conducting device, and is pasted on the surface of the heat-generating component (such as CPU) of the portable device, it absorbs the heat of the heat-generating component of the portable device through heat conduction. Since the two pipelines are respectively connected in series to the fuel supply circuit and the product water circuit, the liquid in the two circuits acts as a heat dissipation medium to absorb heat, and at the same time, the liquid absorbed by each circuit is adjusted by adjusting the liquid flow rate Heat, which in turn controls the temperature rise of the fuel in the fuel circuit.

However, it should be clear that the double-circulation heat exchange components of the present invention are not limited to the structure shown, and those skilled in the art can select heat exchange components of any structure according to needs to realize the connection between the water circulation loop, the fuel circulation loop and the heat-generating components. heat exchange between them.

FIG. 5 shows the detailed operation flow of the fuel cell system at various stages according to the present invention.

By adopting the technical scheme of the invention, the double-circulation heat exchange component is closely combined with the main heating component of the portable device, and the fuel cell is started after the user starts the portable device. The logic control of the fuel cell can be completed by a single-chip microcomputer. The detailed flow chart is shown in Figure 5. In Figure 5, for each judgment step, the direction of the downward arrow indicates that the judgment result is "Yes", and the branch to the left or right The direction of the arrow indicates that the judgment result is "No".

Next, with reference to FIG. 3A , 3B and FIG. 5 , the operation process of each stage of the fuel cell system of the portable device according to the present invention will be described in detail.

Startup process:

After the user initiates the operation of starting the portable device, the starting power supply 305 provides power to drive the fuel pump of the fuel supply and concentration control unit 301, draw fuel from the fuel tank 300 and deliver the fuel through the double cycle heat exchange unit 303 and the fuel concentration control unit 302 , entering the fuel stage of the fuel cell stack 307 , the fuel residue after passing through the fuel cell stack 307 is post-treated by the gas-liquid separation unit 308 , and the residual liquid flows back to the fuel supply and concentration control unit 301 . This process is the fuel secondary cycle operation step (S501).

After the user starts the portable device, before the fuel cell works normally, the main device is powered by the starting power unit 301 .

The dual-cycle heat exchange unit 303 is in close contact with the heat-generating components of the portable device, and the fuel flowing through absorbs the heat from the heat-generating components of the portable device, increasing the temperature of the fuel itself, and then bringing the heat to the fuel level of the fuel cell stack 307 through the secondary fuel cycle. The warm-up process of the fuel cell stack 307 is accelerated and the warm-up time is shortened.

The fuel cell control/conversion/serving unit 306 monitors and adjusts the fuel concentration in the secondary fuel circulation loop through the concentration sensor in the fuel supply and concentration control unit 301 (S513, S514). If the fuel concentration is lower than the predetermined concentration range, the pure fuel intake from the fuel tank 300 is increased (S516). If the fuel concentration is higher than the predetermined concentration range, the water intake from the water collecting/monitoring unit 304 is increased (S515). Make the fuel concentration in the secondary fuel circulation loop be within the ideal predetermined concentration range.

After the user initiates the operation of starting the portable device, the starting power supply 305 provides power to drive the air supply unit 313 to provide air for the air stage of the fuel cell stack 307. Entering the normal power generation state, the reaction product of the air stage of the fuel cell stack 307 gradually increases, and after passing through the condensation/gas-liquid separation unit 310 , the residual water is sent to the water collection/monitoring unit 304 .

The fuel cell control/conversion/serving unit 306 monitors the temperature of the fuel flowing into the fuel cell stack 307 through the temperature sensor in the fuel temperature monitoring unit 302 (S504). After the fuel temperature exceeds the threshold value, the fuel cell control/conversion/serving unit 306 Start the main water circulation operation (S505).

The electric power generated by the fuel cell stack 307 directly drives the water pump of the main water circulation drive unit 312 to provide power for the main water circulation circuit.

Running process:

During the operation of portable equipment, since the temperature of the fuel in the auxiliary fuel circulation loop needs to be controlled within an appropriate temperature range, the main water circulation loop is used to dissipate heat from the heat-generating components of the portable equipment, and at the same time control the fuel in the auxiliary fuel circulation loop. fuel temperature. The water in the water main circulation loop flows through the double heat exchange unit 303, where it establishes a heat exchange connection with the fuel auxiliary circulation loop. While absorbing the heat emitted by the portable device, the water flow in the main water circulation loop can be changed to control the fuel auxiliary circulation loop. The temperature of the circulating loop. The water flowing out from the double heat exchange unit 303 dissipates heat to the outside of the portable device through passive cooling devices such as distribution pipes (S506, S509).

The fuel cell control/conversion/serving unit 306 can control the water main circulation drive unit 312 to adjust the water flow rate in the water main circulation loop, and then adjust the water flow through the double-cycle heat exchange source 303 to adjust the fuel secondary circulation loop The absorption heat distribution with the water main circulation loop (S511). If the temperature of the fuel in the secondary fuel circulation loop cannot be controlled and the temperature of the heat-generating components of the portable device continues to rise (S508, S510) under the condition of the maximum flow rate of the water circulation loop, the fuel cell control/conversion/serving unit 306 will start the auxiliary heat dissipation The unit 311 operates (S512), and adopts an active heat dissipation method to help the main water circulation loop discharge heat out of the portable device. When the temperature of the portable device and the fuel temperature in the secondary fuel circulation loop fall back to the threshold range, the fuel cell control/conversion/serving unit 306 shuts down the operation of the auxiliary cooling unit 311 (S507) to save energy.

The fuel cell control/conversion/serving unit 306 can control the water collection/monitoring unit 304, and the water in the water main circulation loop can be controlled by the water collection/monitoring unit 304 and can be provided to the fuel supply and concentration control unit 301 for diluting pure fuel There is plenty of water.

The fuel cell control/conversion/serving unit 306 can control the condensation/gas-liquid separation unit 310 to adjust the gas-liquid separation ratio of the reaction product discharged from the air stage of the fuel cell stack 307 to ensure that an appropriate amount of water enters the water collection/monitoring unit 304 .

Close process:

After the user issues an operation to turn off the portable device, the fuel cell control/conversion/serving unit 306 first shuts down the fuel supply and concentration control unit 301, stops the secondary fuel cycle, and the fuel cell stack 307 stops generating power. Then start the power supply 305 to provide power, continue to drive the air supply unit 313 and the main water circulation drive unit 311, and within the predetermined delay time, the air supply unit 313 will delay heat dissipation to the fuel cell stack 307. The heat-generating parts of the portable equipment are cooled by the water main circulation loop. After the predetermined time elapses (or after detecting that the temperature of the heating component is lower than the predetermined value), the fuel cell control/conversion/serving unit 306 turns off the starting power. The entire portable system is in a closed state (S502, S503).

The invention utilizes the double cooling cycle of the front-end fuel circulation loop and the back-end by-product water circulation loop of the direct alcohol fuel cell to dissipate heat from the heat-generating components of the portable device. And through the cooling of the main water circulation loop and the enhanced cooling of the auxiliary heat dissipation components, the temperature rise of the fuel on the fuel secondary circulation loop can be effectively controlled, so that the fuel entering the fuel cell stack can maintain an ideal temperature, thereby maintaining high efficiency of fuel cell power generation. The water in the water main circulation loop is further used to dilute the high-concentration fuel, and then the diluted fuel enters the heat exchange components, so that the portable device can carry more energy due to the use of high-concentration fuel.

The present invention has the following advantages:

1. Use water with a large specific heat as the main circulation loop to dissipate heat from the heat-generating components of portable devices, and there is an auxiliary heat-dissipating device on the main circulation loop, which can ensure effective heat dissipation and cooling when the heat-generating components are large;

2. Use the water in the main circulation loop to dilute the high-concentration fuel, making it possible to carry high-concentration or even pure fuel for power generation;

3. Use the diluted fuel as an auxiliary circulation loop to assist heat dissipation of the heat-generating components of the portable device, improve the heat dissipation efficiency and at the same time preheat the temperature of the fuel, thereby improving the power generation efficiency of the fuel cell;

4. The main and auxiliary circulation loops exchange heat through the same double heat exchange component, so the temperature rise of the fuel can be effectively controlled through the flow control of the main and auxiliary circulation loops, that is, the temperature of the fuel entering the fuel cell stack can be strictly controlled. control.

5. The main and auxiliary circulation loops can adapt to different working states of the fuel cell system in different working sequences. When starting, the fuel cell stack needs to heat up quickly, and only the auxiliary circulation circuit works. When shutting down, the fuel cell pack and heat-generating components need to be cooled quickly, and only the main circulation loop and auxiliary heat dissipation equipment work to achieve the fastest cooling time.

In addition, the invention can not only be applied to small portable devices, but also its principle can be applied to medium and large devices driven by power fuel cells.

Finally, it should be noted that the above embodiments are only used to illustrate and not limit the technical solutions of the present invention, although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the present invention can be modified or Any modification or partial replacement without departing from the spirit and scope of the present invention shall fall within the scope of the claims of the present invention.

Claims (14)

1. A fuel cell system for a portable device having a heat generating part, the fuel cell system comprising: A fuel cell body, in which the fuel undergoes a chemical reaction to provide electrical energy, and the resulting reaction product includes water; A fuel supply and circulation driving device, used for controlling the fuel quantity and/or fuel flow rate in the fuel circulation circuit according to the fuel concentration and/or fuel temperature in the fuel circulation circuit; The water circulation drive device is used to control the water volume and/or water flow rate in the water circulation circuit according to the fuel temperature in the fuel circulation circuit and the temperature of the heat-generating components; The fuel circulation circuit constitutes the circuit between the fuel cell main body and the fuel supply and circulation driving device, through which fuel is supplied to the fuel cell main body, and the remaining fuel that has not undergone chemical reactions is sent back to the fuel supply and circulation driving device; a water circulation loop forming a loop in which the water in the reaction product flows; and A double-circulation heat exchange unit, in which heat exchange occurs between the fuel circulation loop, the water circulation loop and the heat-generating components. 2. The fuel cell system for portable equipment according to claim 1, characterized in that it also includes an auxiliary heat dissipation device, which is used to control the temperature of the fuel according to the water amount and/or water flow rate in the water circulation circuit and the fuel temperature in the fuel circulation circuit. Water circulation circuit for heat dissipation. 3. The fuel cell system for portable equipment according to claim 1, characterized in that it also includes a water collection and supply device for collecting the reaction product water, and according to the water temperature in the water circulation loop, supplementing the temperature in the water circulation loop Reaction product water at a temperature lower than that of the water in the water circulation loop, and draining excess water from the water circulation loop. 4. The fuel cell system for portable equipment according to claim 3, characterized in that The water collection and supply device also provides water to the fuel supply and circulation drive device according to the instructions of the fuel supply and circulation drive device; The fuel supply and circulation drive device adjusts the concentration of fuel supplied to the fuel cell main body using the water supplied from the water collection and supply device. 5. The fuel cell system for portable equipment according to claim 1, further comprising an unreacted fuel collection device for separating the remaining fuel and reaction products that have not undergone chemical reactions, and sending the remaining fuel into the fuel cell. Circulation loop, back to fuel supply and circulation drive. 6. The fuel cell system for portable equipment according to any one of claims 1 to 5, further comprising a fuel storage device for storing high-purity fuel. 7. The fuel cell system for a portable device according to any one of claims 1 to 5, characterized in that the heat-generating component is at least one of the central processing unit, memory, image processor and display of the portable device . 8. The fuel cell system for portable equipment according to any one of claims 1 to 5, characterized in that said fuel is methanol. 9. A method of operating a fuel cell system according to any one of claims 1 to 8, comprising the steps of: Activation of the fuel supply and circulation drive to operate the fuel circulation circuit; judging whether the fuel temperature rise has reached the first threshold; When the temperature rise of the fuel reaches the first threshold value, the water circulation driving device is started, so that the water circulation circuit operates; judging whether the fuel temperature has exceeded the second threshold; When the fuel temperature has exceeded the second threshold, it is judged whether the temperature of the heat-generating component exceeds the third threshold; When the temperature of the heat-generating component does not exceed the third threshold, the water circulation driving device is driven to increase the flow in the water circulation loop, and the step of judging the fuel temperature is returned. 10. The operating method of the fuel cell system according to claim 9, further comprising the steps of: The auxiliary radiator is deactivated when the fuel temperature does not exceed the second threshold. 11. The operating method of the fuel cell system according to claim 9, further comprising the steps of: When the temperature of the heating component exceeds the third threshold, it is judged whether the flow rate in the water circulation loop has reached the maximum value; If the flow in the water circuit has reached its maximum value, the auxiliary cooling device is activated. 12. The operating method of the fuel cell system according to claim 11, further comprising the steps of: If the flow in the water circulation loop does not reach the maximum value, drive the water circulation driving device to increase the flow in the water circulation loop, and return to the step of judging the temperature of the heating component. 13. The operating method of the fuel cell system according to claim 9, further comprising the steps of: Judging in parallel with the above steps whether the fuel concentration in the fuel circulation loop is within a pre-specified range; If the fuel concentration exceeds the upper limit of the pre-specified range, water is provided to the fuel supply and circulation drive device for dilution to reduce the fuel concentration; If the fuel concentration falls below the lower limit value of the predetermined range, the fuel supply and circulation drive increases the fuel concentration. 14. The operating method of the fuel cell system according to claim 9, further comprising the steps of: Judging in parallel with the above steps whether an instruction to shut down the fuel cell system is received; The fuel cell system is shut down when an instruction to shut down the fuel cell is received.

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