JP4564247B2 - Fuel cell power generator and pressure adjustment method - Google Patents

Description

  The present invention relates to a fuel cell power generator and a pressure adjusting method for adjusting a pressure difference between cooling water and oxygen or hydrogen.

  In general, by stacking a plurality of cells (single cells) in which an anode side electrode and a cathode side electrode are opposed to each other with a solid polymer electrolyte membrane sandwiched between separators made of metal or carbon having good conductivity Constructed fuel cells are known. In such a stacked fuel cell, if the pressure difference between the cooling water for cooling the inside of the fuel cell and the oxygen or hydrogen supplied to the fuel cell is not within a predetermined range, the fuel cell is configured. Excessive pressure was applied to the film, which could shorten its life.

  In order to solve such problems, conventionally, a balancer container is provided in a circulation line through which cooling water circulates, and an expandable / contractible bellows is provided in the balancer container. There is a pressure balancer that adjusts the pressure of cooling water and air (see Patent Document 1). As another type of pressure balancer, as shown in FIG. 4, one of a cathode gas line GL through which air passes (or an anode gas line through which hydrogen passes) is provided above the balancer vessel BB to which cooling water is supplied. By connecting the parts and adjusting the position of the interface between the cooling water and the air in the balancer vessel BB, there is one in which the pressure difference between the cooling water and the air falls within a predetermined range. Furthermore, as another type of pressure balancer, instead of connecting the cathode gas line GL to the upper portion of the balancer vessel BB, a valve that is opened when the pressure inside the vessel exceeds a predetermined value is provided, thereby cooling the vessel. Some have the water pressure within a predetermined range (see Patent Document 2).

  Of the two pressure balancers described above, the latter two types are in direct contact with cooling water and air, so even if air is mixed in the cooling water discharged from the fuel cell, for example. Can be separated from the cooling water in the balancer vessel BB. And in order to implement | achieve such a gas-liquid separation favorably, it is necessary to provide a pressure balancer in the uppermost part of a cooling system.

Japanese Patent Laying-Open No. 2003-3251 (paragraphs 0030 and 0033, FIG. 4) JP 2002-124269 A (paragraphs 0024 and 0025, FIG. 1)

  However, in the conventional pressure balancer, the balancer container is provided separately from the cooling system mainly composed of the radiator and the piping, so that the cost is increased accordingly. In addition, in the type in which air and cooling water are in direct contact with each other, it is troublesome to lay out the pressure balancer at the top of the cooling system, and it is necessary to connect piping to the pressure balancer provided above, so the cooling system is large. There was a problem.

  Furthermore, in the pressure balancer shown in FIG. 4, the cooling water depth (the distance from the water surface to the cooling water outlet) is set so that the air supplied from the cathode gas line GL does not go out together with the cooling water from the cooling water outlet. Therefore, it is difficult to downsize the balancer vessel BB itself and downsize the entire cooling system.

  Therefore, in the present invention, by enabling pressure adjustment without providing a balancer container separately from the cooling system, a fuel cell power generator and pressure adjustment that can contribute to cost reduction and downsizing of the cooling system. It aims to provide a method.

The invention according to claim 1 of the present invention that has solved the above problem is that hydrogen gas and oxygen gas are supplied from a hydrogen gas supply pipe and an oxygen gas supply pipe, respectively. In a fuel cell power generation apparatus comprising a fuel cell that generates electricity by an electrochemical reaction and a cooling water circulation passage that circulates cooling water between the fuel cell and the radiator, the fuel cell power generation device is mixed in the cooling water that circulates in the radiator. A gas-liquid separation part having a gas phase chamber for separating the gas to be formed is formed on the upper part of the radiator so that the inside of the radiator protrudes upward, and the hydrogen gas supply pipe or the oxygen gas supply pipe The pressure of the cooling water and the pressure of the hydrogen gas or the oxygen gas are communicated between the signal pressure pipe branched from the gas phase and the gas phase chamber of the gas-liquid separation unit. Characterized in that in balancing.

  According to the first aspect of the present invention, the pressure of the cooling water in the radiator and the pressure of the hydrogen gas or oxygen gas are adjusted in the gas-liquid separator provided in the upper portion of the radiator. That is, the function of the conventional balancer container is given to the radiator, and it is not necessary to provide the balancer container separately. In addition, the gas-liquid separation unit can be positioned at the top of the cooling system simply by positioning the upper portion of the radiator at the top of the cooling system, which facilitates the layout. Further, since the radiator serves as a conventional balancer container having a gas-liquid separation function, it is not necessary to extend the cooling water pipe to the separately provided balancer container.

According to a second aspect of the present invention, there is provided a fuel cell that generates power by an electrochemical reaction between the hydrogen gas and the oxygen gas by supplying hydrogen gas and oxygen gas from a hydrogen gas supply pipe and an oxygen gas supply pipe, respectively. And a cooling water circulation passage that circulates cooling water between the fuel cell and the radiator, and adjusts the pressure of the hydrogen gas or the oxygen gas and the pressure of the cooling water. In the pressure adjusting method, a part of the hydrogen gas or the oxygen gas is mixed in the cooling water in the gas-liquid separation part formed so that the inside of the radiator protrudes upward at the upper part of the radiator. It is to introduce the gas phase chamber for separating gas, the pressure of the hydrogen gas or the oxygen gas, and wherein the pressure of the cooling water to balance within the radiator That.

  According to the second aspect of the present invention, the pressure of the hydrogen gas or oxygen gas and the pressure of the cooling water are adjusted in the radiator. That is, according to this method, it is possible to adjust the pressure only by introducing a part of hydrogen gas or oxygen gas from the upper portion of the radiator without providing a separate balancer container as in the prior art. In addition, by introducing a part of hydrogen gas or oxygen gas from the top of the radiator, the gas separated from the cooling water in the radiator can be stored in this introduction part, so that it also has a function of gas-liquid separation Can do.

  According to the first aspect of the present invention, since the radiator has the function of the conventional balancer container, it is not necessary to separately provide the balancer container, and the cost can be reduced correspondingly, and the cooling system Can be miniaturized. In addition, the gas-liquid separation unit can be positioned at the top of the cooling system simply by positioning the upper portion of the radiator at the top of the cooling system, which facilitates the layout. Furthermore, since the radiator serves as a balancer vessel, the piping to the balancer vessel provided in the past can be omitted, and the cost can be reduced correspondingly, and the cooling system can be downsized.

  According to the second aspect of the present invention, it is possible to adjust the pressure only by introducing a part of hydrogen gas or oxygen gas from the upper part of the radiator without providing a separate balancer vessel as in the prior art. The cost can be reduced accordingly.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a side view showing a vehicle equipped with a fuel cell power generator according to the present embodiment, FIG. 2 is a configuration diagram showing details of the fuel cell power generator of FIG. 1, and FIG. 3 is a radiator of FIG. It is an enlarged view which shows the gas-liquid separation part provided in FIG.

  As shown in FIG. 1, the fuel cell power generator 1 includes a fuel cell 2 disposed under a floor of a vehicle interior (not shown) of a vehicle M, a radiator 3 disposed in front of the vehicle M, a fuel cell 2, A cooling water circulation channel 4 that circulates cooling water with the radiator 3 is mainly provided. The fuel cell 2 generates power using air and hydrogen supplied from an air supply source such as an air compressor (not shown) and a hydrogen supply source such as a hydrogen tank.

  As shown in FIG. 2, the fuel cell 2 is supplied with hydrogen gas and air (oxygen gas) from a hydrogen gas supply pipe 21 and an air supply pipe (oxygen gas supply pipe) 22, respectively. It generates electricity by electrochemical reaction with oxygen gas. The air supply pipe 22 is bifurcated at an appropriate position, one battery side pipe 22 a is connected to the fuel cell 2, and the other signal pressure pipe 22 b is connected to the upper portion of the radiator 3.

  The radiator 3 is a radiator for cooling the fuel cell 2, and is specifically heated in the fuel cell 2 between a plurality of fins 31,... Cooled by air blown from a fan (not shown). The cooling water is cooled by flowing the cooling water. The radiator 3 has a so-called side flow system in which cooling water flows in a plane direction, and a gas-liquid separation unit 32 formed so as to protrude upward is disposed at an upper part on the downstream side of the flow. Has been.

  The gas-liquid separation unit 32 has a gas phase chamber 32a for separating air (gas) mixed in the cooling water flowing through the radiator 3 therein. And the signal pressure piping 22b is connected to the upper wall 32b of the gas-liquid separation part 32 so that the above-mentioned signal pressure piping 22b may communicate directly with this gas phase chamber 32a.

  As shown in FIG. 1, the fuel cell 2 is disposed under the floor of the vehicle M, and the radiator 3 is disposed in front of the vehicle M, as shown in FIG. Thus, the gas-liquid separator 32 is positioned at the top of the cooling system because it is positioned at the top of the cooling system mainly composed of the radiator 3 and the cooling water circulation passage 4. Moreover, since the radiator 3 is larger than the conventional balancer container, as shown in FIG. 3, the water depth (distance from the water surface to the outlet of the cooling water) that has been required in the past should be sufficiently secured. It becomes. In other words, since the cooling water in the radiator 3 also serves as the cooling water required in the conventional balancer vessel, the size of the cooling water required in the past (the range indicated by the hatched area in the figure) can be reduced. You can plan.

  As shown in FIG. 2, the cooling water circulation channel 4 includes a supply channel 41 for supplying the cooling water cooled by the radiator 3 to the fuel cell 2, and the cooling water discharged from the fuel cell 2 again with the radiator. And a return flow path 42 for returning to 3. The supply channel 41 is connected to the lower part of the radiator 3 on the downstream side of the fins 31,..., And the return channel 42 is connected to the upper part of the radiator 3 on the upstream side of the fins 31,. Yes. A circulating pump 43 for circulating the cooling water in one direction in the cooling water circulation channel 4 is provided at an appropriate position of the return channel 42. Although not shown in the figure, a bypass channel that bypasses the radiator 3 is provided between the supply channel 41 and the return channel 42, and cooling is performed at an appropriate position of the bypass channel according to the water temperature. A thermostat valve is provided for switching the flow path through which the water passes to a bypass flow path and a flow path on the radiator 3 side.

Next, a pressure adjustment method using the fuel cell power generator 1 will be described with reference to FIG.
First, air and hydrogen gas are supplied to the fuel cell 2 from an air compressor and a hydrogen tank (not shown), and the cooling pump 43 is driven to circulate cooling water. Thus, when the supply of air or cooling water to the fuel cell 2 is started, the pressure of the air becomes a value corresponding to the rotation speed of the air compressor, and the pressure of the cooling water becomes the rotation speed of the circulation pump 43. It becomes a value according to.

  When a change occurs in the output of the fuel cell 2, a controller (not shown) controls the rotational speed of the air compressor so that the air supply flow rate is in accordance with the output. Further, the controller controls the circulation pump 43 so that the flow rate of the cooling water corresponds to the output (that is, the power generation amount) of the fuel cell 2. Here, the pressure of the air and the pressure of the cooling water fluctuate with the change in the flow rate, but by connecting the gas phase chamber 32a provided at the upper part of the radiator 3 and the air signal pressure pipe 22b, the radiator 3 Since the pressure of the cooling water inside and the pressure of the air in the gas phase chamber 32a are balanced substantially equally, the pressure difference between the air supplied to the fuel cell 2 and the cooling water falls within a predetermined pressure range. become. That is, since the pressure fluctuation caused by changing the flow rate can be allowed by the radiator 3, the controllability of the air compressor, the circulation pump 43 and the like is improved, and the pressure difference between the reaction gas and the cooling water is set to a predetermined pressure. The range can be maintained, and damage to the solid polymer film can be reduced.

  When air is mixed in the cooling water in the fuel cell 2, the air contained in the cooling water as bubbles rises on the downstream side of the fins 31,. By entering the gas phase chamber 32a, it is separated from the cooling water. This prevents air from accumulating in the cooling water circulation channel 4 or between the fins 31 of the radiator 3.

According to the above, the following effects can be obtained in the present embodiment.
Since the radiator 3 has the function of the conventional balancer container, there is no need to provide a separate balancer container, and the cost and size can be reduced accordingly.

  Since the gas-liquid separation unit 32 that also functions as a pressure balancer is provided at the top of the radiator 3 that is the uppermost part of the cooling system, a balancer container that is separately provided as in the prior art is laid out at the uppermost position of the cooling system. Therefore, it is not necessary to study the structure around the balancer container in detail, and the layout becomes easy. Further, since it is not necessary to extend the pipe to the balancer container provided separately as in the conventional case, the cooling system can be reduced in size accordingly.

  Since the air accumulated in the cooling water circulation passage 4 is discharged through the signal pressure pipe 22b by the gas-liquid separator 32, the circulation pump 43 is operated well without biting the air. Moreover, since air does not accumulate between the fins 31 of the radiator 3 by the gas-liquid separation part 32, the heat transfer performance of the radiator 3 can also be maintained.

As mentioned above, this invention is implemented in various forms, without being limited to the said embodiment.
In the present embodiment, the signal pressure pipe 22 b is provided in the air supply pipe 22, but the present invention is not limited to this, and the signal pressure pipe 22 b may be provided in the hydrogen gas supply pipe 21.
In the present embodiment, the gas-liquid separation unit 32 is provided on the upper portion on the downstream side of the fin 31, but the present invention is not limited to this, and for example, the gas-liquid separation unit 32 may be provided on the upper portion on the upstream side of the fin 31. Good. However, when the gas-liquid separator 32 is provided on the upstream side, the air in the gas-liquid separator 32 may be caught in the cooling water sent from the fuel cell 2 side and flowed downstream. In the case where the gas-liquid separation part 32 is provided on the downstream side as in the present embodiment, there is no possibility of this, so it is desirable to adopt such a structure.

  Moreover, you may utilize the existing protrusion part for attaching a radiator cap as the gas-liquid separation part 32. FIG. In this way, the cost can be reduced, and the coolant can be replenished and the gas-liquid separator 32 can be simultaneously maintained by simply removing the radiator cap.

  In the present embodiment, the side flow type radiator 3 is adopted. However, the present invention is not limited to this, and for example, a down flow type radiator in which cooling water flows from top to bottom may be adopted. However, in this case, the direction of the pressure applied to the cooling water in the radiator from the gas-liquid separation unit and the direction of the flow of the cooling water match, so the air in the gas-liquid separation unit is caught in the cooling water flowing from the top to the bottom. There is a possibility of going out from the exit. On the other hand, in the side flow type radiator 3 as in the present embodiment, the cooling water flows in the radiator 3 in a direction different from the direction of the pressure applied to the cooling water from the gas-liquid separator 32. It is possible to reliably prevent the air in the gas-liquid separation unit 32 from being caught in the cooling water flowing in the radiator 3 and going out from the outlet.

It is a side view which shows the vehicle carrying the fuel cell electric power generating apparatus which concerns on this embodiment. It is a block diagram which shows the detail of the fuel cell electric power generating apparatus of FIG. It is an enlarged view which shows the gas-liquid separation part provided in the radiator of FIG. It is a perspective view which shows the conventional pressure balancer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell power generation apparatus 2 Fuel cell 3 Radiator 4 Cooling water circulation flow path 21 Hydrogen gas supply piping 22 Air supply piping 22a Battery side piping 22b Signal pressure piping 31 Fin 32 Gas-liquid separation part 32a Gas phase chamber 32b Upper wall 41 Supply flow Path 42 Return path 43 Circulation pump M Vehicle

Claims (2)

A fuel cell that generates electricity by an electrochemical reaction between the hydrogen gas and the oxygen gas by supplying hydrogen gas and oxygen gas from a hydrogen gas supply pipe and an oxygen gas supply pipe, respectively;
In a fuel cell power generator comprising: a cooling water circulation passage for circulating cooling water between the fuel cell and the radiator;
Forming a gas-liquid separation part having a gas phase chamber for separating gas mixed in the cooling water flowing through the radiator so that the inside of the radiator protrudes upward at the upper part of the radiator ;
The pressure of the cooling water and the pressure of the hydrogen gas or the oxygen gas are communicated with the signal pressure pipe branched from the hydrogen gas supply pipe or the oxygen gas supply pipe and the gas phase chamber of the gas-liquid separation unit. Is balanced in the radiator. A fuel cell power generator. A fuel cell that generates electricity by an electrochemical reaction between the hydrogen gas and the oxygen gas by supplying hydrogen gas and oxygen gas from a hydrogen gas supply pipe and an oxygen gas supply pipe, respectively;
In a fuel cell power generation device comprising a cooling water circulation passage for circulating cooling water between the fuel cell and the radiator, a pressure for adjusting the pressure of the hydrogen gas or the oxygen gas and the pressure of the cooling water An adjustment method,
Gas for separating the gas mixed in the cooling water in the gas-liquid separation part formed so that the hydrogen gas or a part of the oxygen gas protrudes upward at the upper part of the radiator. A pressure adjustment method characterized by balancing the pressure of the hydrogen gas or the oxygen gas and the pressure of the cooling water in the radiator by introducing the phase into the phase chamber .

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