JP7114502B2 - fuel cell system - Google Patents

Description

Embodiments relate to fuel cell systems.

A fuel cell is a device that generates electricity through an electrochemical reaction between hydrogen and oxygen. Fuel cells generate heat as they generate electrical chemical reactions. In order for the fuel cell to continue power generation, it is necessary to maintain the fuel cell at a predetermined temperature, and the fuel cell is cooled by supplying cooling water. In order to make effective use of the heat generated by the fuel cell, it is common to have a system that supplies heat as needed.

Conventional fuel cell systems often include two lines, a cell cooling line for cooling the fuel cell and an exhaust heat recovery line for recovering heat from the cell cooling line, as shown in Patent Document 1, for example. The fuel cell is cooled in the battery cooling line, and the heat in the battery cooling line is transferred to the exhaust heat recovery line via a heat exchanger provided on the battery cooling line. A heat exchanger is also a device that constitutes an exhaust heat recovery line. Then, the heat is utilized by supplying the heat to the customer in the customer-use heat exchanger on the exhaust heat recovery line.

Japanese Patent No. 5092960

In the technique described above, two completely independent lines are connected by a heat exchanger, but the provision of such two lines enables the constant utilization of waste heat. It is effective in a system with a high However, in a system where the exhaust heat utilization rate is low and the scale and utilization rate of the exhaust heat recovery line are low, the provision of two independent lines complicates the configuration of the entire system and causes an increase in cost. In particular, in the conventional technology, since heat is transferred between two lines via a heat exchanger, the system becomes larger than a configuration in which waste heat is directly supplied to the customer's heat dissipation means, and the heat exchange It is also unsuitable for systems with low heat utilization, in other words, with little available heat energy.

The fuel cell system of this embodiment has been proposed to solve the above-described problems of the prior art. provide the system.

The fuel cell system of the embodiment has the following configuration.
(1) An exhaust heat recovery line for circulating the cooling water from the fuel cell main body to the fuel cell main body via heat dissipation means.
(2) A cooling line for circulating cooling water for cooling the fuel cell main body without passing through the heat radiation means.
(3) A three-way control valve that branches the cooling water flowing out of the fuel cell main body to the exhaust heat recovery line and the cooling line.
(4) A control unit that controls opening degrees of the three-way control valve with respect to the cooling line side and the exhaust heat recovery line side.
(5) calorie detection means for detecting heat radiation capability of cooling water flowing out from the fuel cell main body;
(6) The control section controls the opening degrees of the cooling line side and the exhaust heat recovery line side according to the heat radiation capacity of the cooling water flowing out of the fuel cell main body detected by the heat quantity detecting means.
(7) The calorie detection means is a data storage unit that stores data indicating the correspondence relationship between the operation state detection means of the fuel cell body and the temperature of cooling water flowing out of the fuel cell body in the operation state of the fuel cell body.
(8) The control unit detects the operating state of the fuel cell body detected by the operating state detection means and the cooling water temperature data stored in the storage unit corresponding to the operating state. Controls the opening of the regulating valve.

It is a piping diagram of a 1st embodiment. It is a piping diagram of a 2nd embodiment. It is a piping diagram of 3rd Embodiment. It is a piping diagram of a 4th embodiment.

Hereinafter, embodiments will be described with reference to the drawings. The same parts in the drawings are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate, and different parts will be described.

[1. First Embodiment]
[1-1. Constitution]
As shown in FIG. 1, the fuel cell system of this embodiment includes a fuel cell body 1, a pump 2 that supplies cooling water to the fuel cell body 1, and exhaust heat from the cooling water heated by the fuel cell body 1. is provided with an exhaust heat recovery line HL that connects the radiators 3 that utilize As the heat radiator 3, for example, a known heat radiation means such as an air cooling fan, radiator, or heat exchanger can be appropriately used.

The fuel cell system includes a cooling line BL that circulates cooling water between the fuel cell body 1 and the pump 2 as a bypass of the exhaust heat recovery line HL without passing through the radiator 3 of the exhaust heat recovery line HL. . A three-way control valve 4 that divides the cooling water flowing out of the fuel cell body 1 into two lines is provided at the branched portion of the exhaust heat recovery line HL and the cooling line BL.

The three-way regulating valve 4 has a control section 5 that adjusts the degree of opening thereof. The control unit 5 switches the cooling water flow between the exhaust heat recovery line HL and the cooling line BL manually or based on data from various sensors and detectors, or data on the operating status of the fuel cell body 1, or , means for adjusting the flow distribution of the cooling water flowing through the exhaust heat recovery line HL and the cooling line BL.

In this embodiment, the control unit 5 is an operation switch provided on the radiator 3. When the user of the system turns on the operation switch to utilize the waste heat of the cooling water in the radiator 3, three-way adjustment is performed. The valve 4 is switched to the exhaust heat recovery line HL side, and the cooling water flows to the exhaust heat recovery line HL side. In addition, when a switch that allows selection of operation levels such as strong, medium, and weak is used as the operation switch, the opening of the three-way control valve 4 changes according to the operation level, thereby recovering exhaust heat. The diversion level of the cooling water flowing in line HL is adjusted.

Although not shown in particular, in the exhaust heat recovery line HL, in addition to the radiator 3 for exhaust heat used by the user, various conventionally known radiators and heat exchangers (for example, a user heat exchanger, a device protection heat exchanger) can be provided. Various devices provided in the exhaust heat recovery line HL in the fuel cell system, such as a water treatment device, a flow meter, a pressure valve, a cooling water leakage monitoring device, and an alarm device, can also be provided.

[1-2. Action/effect]
In the fuel cell system of this embodiment having the configuration described above, the cooling line BL is bypass-connected to the exhaust heat recovery line HL. As compared with the conventional technology in which the HL is connected, no heat exchanger is required, which simplifies the system configuration. In addition, when the exhaust heat is used, the cooling water from the fuel cell body 1 can be directly supplied to the radiator 3, so the heat efficiency is also good.

In this embodiment, the three-way regulating valve 4 is relatively simple in that the cooling water is passed through the exhaust heat recovery line HL when the amount of exhaust heat is large, and the cooling water is allowed to flow through the cooling line BL when the amount of exhaust heat is small. It has the advantage that it can be done with small parts. Therefore, according to the present embodiment, the frequency of use of exhaust heat is low, that is, the amount of heat contained in the cooling water is small. Even in a system incapable of

Furthermore, in a conventional small-scale fuel cell system, since the amount of exhaust heat to be used is small, it is conceivable to provide only an exhaust heat recovery line to constantly supply cooling water to the radiator 3. If water is supplied, cooling water with a low temperature may be supplied to the radiator 3 depending on the operating conditions of the fuel cell body 1, which may cause inconvenience to the user. Since the HL is supplied only with cooling water having a heat quantity for heat release, such inconvenience does not occur.

[2. Second Embodiment]
2nd Embodiment shown in FIG. 2 adjusts the opening degree of the three-way control valve 4 automatically. In this embodiment, a thermometer 6 is provided after the fuel cell body 1 as heat quantity detection means for detecting the heat dissipation capability of the cooling water flowing out of the fuel cell body 1 . The control unit 5 controls the opening degree of the three-way control valve 4 based on the detection result of the thermometer 6 . That is, when the temperature of the cooling water flowing out of the fuel cell main body 1 is high as indicated by the thermometer 6, the amount of usable exhaust heat is large. By switching over, high-temperature cooling water is allowed to flow to the side of the radiator 3 so that it can be used by the user.

In this case, when the temperature of the cooling water detected by the thermometer 6 is equal to or higher than a certain value, the control unit 5 may switch all three-way control valves 4 from the cooling line BL side to the exhaust heat recovery line HL side. The diversion flow rate by the three-way control valve 4 may be adjusted according to the set temperature level.

According to the second embodiment having such a configuration, the degree of opening of the three-way regulating valve 4 is automatically adjusted according to the temperature of the coolant sent from the fuel cell body 1 . As a result, even if the user does not specifically monitor the operating conditions of the fuel cell, cooling water having a usable heat quantity is supplied to the radiator 3 in accordance with the heat quantity of the usable exhaust heat. A fuel cell system capable of utilizing waste heat can be obtained.
[3. Third Embodiment]
In the third embodiment shown in FIG. 3, a thermometer 6 is provided downstream of the radiator 3 as heat quantity detection means for detecting the heat dissipation capability of the cooling water flowing out of the fuel cell main body 1 . The control unit 5 controls the opening degree of the three-way control valve 4 based on the detection result of the thermometer 6 . That is, when the temperature of the cooling water flowing out of the radiator 3 is high according to the thermometer 6, even after the waste heat is recovered and used in the radiator 3, the cooling water flowing through the exhaust heat recovery line HL is high, in other words, the temperature of the cooling water sent from the fuel cell body 1 is high.

Therefore, the heat quantity of exhaust heat that can be used by the cooling water is estimated from the detection result of the thermometer 6 at the rear stage of the radiator 3. It is switched to the line HL side, and high-temperature cooling water is flowed to the radiator 3 side so that it can be used by the user.

According to the third embodiment having such a configuration, the degree of opening of the three-way regulating valve 4 is automatically adjusted according to the temperature of the cooling water after exhaust heat is utilized by the radiator 3 . As a result, similarly to the second embodiment, it is possible to obtain an easily handled fuel cell system capable of utilizing waste heat. In addition, by detecting the temperature of the part near the point where waste heat is used, which is the latter stage of the radiator 3, it is possible to control the three-way control valve 4 in consideration of the operating conditions of the radiator 3. It is possible to adjust the flow rate with high accuracy according to the amount.

[4. Fourth Embodiment]
The fourth embodiment shown in FIG. 4 utilizes the operating conditions of the fuel cell body 1 as heat quantity detection means for detecting the heat radiation capability of the cooling water flowing out of the fuel cell body 1 . That is, since the outlet temperature of the fuel cell body 1 is determined according to the operating conditions of the fuel cell body 1, the opening degree of the three-way control valve 4 is adjusted so that the amount of flow corresponding to the operating conditions flows into the exhaust heat recovery line HL. .

Therefore, in this embodiment, the operating state detection device 7 of the fuel cell main body 1 is provided as a heat amount detection means. As the detection device 7, a device that detects the operating level of the fuel cell body 1, the operating speed of the pump 2, and the like can be used. The control unit 5 is provided with a storage unit 8 for storing data indicating the relationship between the temperature of the cooling water flowing out of the fuel cell body 1 and the operating state of the fuel cell body 1 detected by the detection device 7 .

In this embodiment having such a configuration, the control unit 5 determines the operating state of the fuel cell body 1 detected by the detecting device 7 and the cooling water temperature stored in the storage unit 8 corresponding to the operating state. Based on the data, the opening degree of the three-way control valve 4 is controlled.

According to this embodiment, the degree of opening of the three-way regulating valve 4 is automatically adjusted according to the operating conditions of the fuel cell body 1. As a result, similar to the second embodiment, an easy-to-handle exhaust heat utilization is possible. A fuel cell system can be obtained. Further, the device 7 for detecting the operational status of the fuel cell body 1 can also be used as the operation control device for the fuel cell body 1 and the pump 2 without providing a separate device such as the thermometer 6 as in the second and third embodiments. can be used as it is.

[Other embodiments]
Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

HL Exhaust heat recovery line BL Cooling line 1 Fuel cell body 2 Pump 3 Radiator 4 Three-way control valve 5 Control unit 6 Thermometer 7 Operation status detection device 8 Storage units 9a to 9c …pressure gauge

Claims (4)

an exhaust heat recovery line for circulating cooling water from a fuel cell body to the fuel cell body via a heat dissipation means ;
a cooling line for circulating cooling water for cooling the fuel cell main body without passing through the heat radiation means;
a three-way control valve for branching the cooling water flowing out of the fuel cell main body to the exhaust heat recovery line and the cooling line;
a control unit that controls opening degrees of the three-way control valve with respect to the cooling line side and the exhaust heat recovery line side ;
a calorie detection means for detecting the heat dissipation capability of the cooling water flowing out of the fuel cell body,
The control unit controls opening degrees to the cooling line side and the exhaust heat recovery line side according to the heat radiation capacity of the cooling water flowing out of the fuel cell main body detected by the heat amount detecting means,
wherein the heat amount detection means is a data storage unit that stores data indicating a correspondence relationship between the operating state detection means of the fuel cell body and the temperature of cooling water flowing out of the fuel cell body in the operating state of the fuel cell body;
The control unit controls the operation of the three-way control valve based on the operating state of the fuel cell body detected by the operating state detecting means and the cooling water temperature data stored in the storage unit corresponding to the operating state. A fuel cell system characterized by controlling the degree of opening . 2. The apparatus according to claim 1 , wherein said heat amount detection means is a thermometer provided at a stage subsequent to said fuel cell body, and said control section controls the degree of opening of said three-way regulating valve based on the detection result of said thermometer. fuel cell system. The heat amount detection means is a thermometer provided downstream of the heat dissipation means provided in the exhaust heat recovery line, and the control unit adjusts the opening of the three-way control valve based on the detection result of the thermometer. The fuel cell system according to claim 1 , which controls. wherein the heat amount detection means is a data storage unit that stores data indicating a correspondence relationship between the operating state detection means of the fuel cell body and the temperature of cooling water flowing out of the fuel cell body in the operating state of the fuel cell body;
The control unit controls the operation of the three-way control valve based on the operating state of the fuel cell body detected by the operating state detecting means and the cooling water temperature data stored in the storage unit corresponding to the operating state. 2. The fuel cell system according to claim 1 , wherein the degree of opening is controlled.

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