JP2015098946A - Heat exchanger for fuel battery circulation water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger for fuel battery circulation water that prevents the elution of resin residual ions in circulation water discharged from a fuel battery.SOLUTION: A resin tank body 4 is produced with polyphthalamide (PPA) resin as material.

Description

  The present invention mainly relates to a heat exchanger for circulating water in a fuel cell for cooling the circulating water in a fuel cell used for an electric vehicle, and particularly relates to a technique for suppressing ion elution from a resin tank to the circulating water. .

In recent years, heat exchangers that cool circulating water discharged from fuel cells of electric vehicles have been actively improved.
This is to prevent catalyst poisoning in the fuel cell due to ion elution.
That is, when metal ions are eluted into the circulating water from the metal member of the heat exchanger arranged in the circulation path, and the metal ions enter the fuel cell, the catalyst in the fuel cell is poisoned and the power generation performance is reduced. May decrease.
Therefore, it is necessary to prevent metal ions from eluting from the heat exchanger into the circulating water.

As means for suppressing elution of metal ions from the heat exchanger, a heat exchanger described in Patent Document 1 and a tank for heat exchanger described in Patent Document 2 have been proposed.
In Patent Document 1, a heat exchanger component made of an aluminum material is assembled through a flux brazing material, and is integrally brazed in a high-temperature furnace to manufacture a heat exchanger, and then the inside is resin-coated. Is used. Thereby, it is described that the outflow of metal ions in the flux and from the heat exchanger components can be prevented.

In Patent Document 2, a member other than a tank is molded from an aluminum material, a core is assembled, a resin coating is performed inside the core, and a resin tank is molded by injection molding, and then the core and the resin tank are caulked. The heat exchanger is manufactured by fixing by, for example.
Generally, fillers (glass fiber, calcium carbonate, talc, mica, etc.) are added to resin materials used for resin molded products (in this example, tanks) to increase heat resistance and rigidity after molding. Has been. As the filler, an inorganic powder obtained by finely pulverizing mineral is used. This inorganic powder is easily decomposed into ions, and ions (for example, metal ions such as silicon ions and magnesium ions) are easily eluted from the resin material. As a reason for ion elution from the resin material, it is considered that the bond of the resin undergoes hydrolysis in water, and the metal ions bound by the bond are eluted.

  In the tank of the heat exchanger of the above-mentioned document 2, in order to prevent the metal ions of the filler in the resin material from being mixed into the circulating water by using the heat exchanger, polyphenylene which is relatively difficult to cause ion elution by hydrolysis. It is proposed to manufacture a tank using a sulfide (hereinafter referred to as PPS) resin.

Japanese Patent Laid-Open No. 2001-167782 JP 2005-093227 A

However, according to the inventors of the present application, when a heat exchanger tank was prototyped using PPS resin, the PPS resin tank was fragile and weak against pressure fluctuations, and was not suitable as a heat exchanger tank. It is clear. Moreover, although PPS resin has hydrolysis resistance more than the resin material used conventionally, what has resistance further is calculated | required now.
Accordingly, an object of the present invention is to provide a heat exchanger for circulating water in a fuel cell using a resin tank that has a hydrolysis resistance and is resistant to pressure fluctuations, instead of a PPS resin.

According to the present invention, the flat tubes (1) and the corrugated fins (10) are alternately arranged in parallel, and both ends of the flat tubes (1) are penetrated by the header plate (2). Core (3) with fixed,
A fuel cell circulating water comprising a pair of resin tank bodies (4) each formed in a long and narrow box shape with one end open, and the periphery of the header plate (2) being caulked and fixed to the outer periphery of the opening edge In heat exchangers for
A heat exchanger for circulating water in a fuel cell, characterized in that the resin tank body (4) is molded from polyphthalamide resin.

According to a second aspect of the present invention, in the heat exchanger for circulating fuel cell water according to the first aspect,
On the outer surface of each resin tank body (4), a plurality of shroud-fixing bosses (7) are provided so as to be separated from each other and integrally project, and the bosses (7) have a wind guide shroud (9). ) Is a heat exchanger for circulating water in a fuel cell, which is fixed by a fastener (8).

According to a third aspect of the present invention, in the heat exchanger for circulating fuel cell water according to the first or second aspect,
A fuel cell circulating water heat exchanger in which the flat tubes (1) are arranged in parallel in the horizontal direction and the resin tank body (4) is disposed on both sides of the core (3).

According to a fourth aspect of the present invention, in the heat exchanger for circulating fuel cell water according to the third aspect,
The fuel cell circulating water heat exchanger includes a spraying device (15) for spraying at least part of the generated water generated by power generation of the fuel cell (12).

  Since the inventor of the present application uses polyphthalamide (hereinafter abbreviated as PPA) as a resin material used for the resin tank body, there is little ion elution from the resin itself into pure water. That is, since the PPA resin is less susceptible to ion elution at a high temperature than conventional resins, catalyst poisoning of the fuel cell can be suppressed as much as possible. In addition, when a resin tank body is formed using PPA resin, it has physical durability when used at high temperatures, and the heat for circulating fuel cell water is higher than that of a conventional resin tank body. Suitable for exchangers.

  In addition to the above configuration, as described in claim 2, a plurality of shroud-fixed boss portions 8 are integrally projected on the outer surface of each resin tank body 4, and the boss portions 7 are used for wind guidance. When the end portion of the shroud is fixed via the fastener 7, the resin tank body 4 is made of PPA resin, so that it has physical durability during high temperature use, the shroud load, and the wind guide The strength of the boss portion 7 to which the load associated with is applied is ensured, and a highly durable heat exchanger can be provided.

  Further, as in the third aspect of the invention, when the flat tubes 1 are arranged in parallel in the horizontal direction and the resin tank body 4 is disposed on both sides of the core 3, the resin tank body is used at the time of high temperature use. Since the PPA resin has physical durability, the vertical dimension of the heat exchanger can be reduced without worrying about insufficient strength due to the direction of installation of the heat exchanger, and the heat exchanger is installed. The vehicle height of the vehicle can be kept low. In addition, the fuel cell vehicle has a lower flow rate than the gasoline vehicle, so it is necessary to ensure a flow rate. However, the flat tubes 1 are arranged in parallel in the horizontal direction, and the resin tank body 4 is the core. 3 are arranged on both sides, the flow passage cross-sectional area is kept small, the flow velocity can be secured, and the performance is improved.

  Further, as in the invention of claim 4, when the spray device for spraying the generated water generated by the fuel cell is provided, the resin tank body is a PPA resin tank excellent in chemical resistance. Without worrying about the damage of the resin tank body due to the contained acidic water, it is possible to improve the heat dissipation performance by the heat of vaporization of the sprayed generated water.

The principal part front view of the heat exchanger for fuel cell circulating water of this invention. The front view which provided the shroud 9 in the same heat exchanger. The principal part sectional drawing in the tank part of the heat exchanger for fuel cell circulating water of this invention. The figure which shows the electrical conductivity measurement result of a resin material. Performance comparison diagram of resin materials. The figure which shows the result of the tensile strength test of PPS and PPA. The figure which shows the result of the distortion test of PPS and PPA. Explanatory drawing of the circulation path of the fuel cell circulating water of this invention.

Next, an embodiment of the present invention will be described.
As shown in FIGS. 1 and 2, the core 3 of the heat exchanger for circulating fuel cell water used in the present invention includes a flat tube 1 through which the circulating fuel cell water flows and a corrugated fin 10 in the horizontal direction. The both ends of each flat tube 1 are penetrated by a pair of header plates 2 having a large number of through holes.
The header plate 2 is formed by press molding, and a recess 2b is formed in an annular groove on the periphery of the bottom. A stepped portion 4a of a resin tank body 4 to be described later is seated through the O-ring 6 in the recess 2b. In addition, a large number of claw portions 2a project from the end portion of the side wall of the header plate 2 so as to be separated from each other.

The opening end portion of each flat tube 1 passes through each through hole of the header plate 2, and corrugated fins are interposed between the flat tubes 1 in this example. A brazing material is applied between the respective members, and the respective parts are brazed and fixed integrally in the furnace.
The core 3 of the heat exchanger for circulating water in the fuel cell is formed by coating the inner surface of the flat tube 1 and the inner side of the header plate 2 with a coating material 5 made of resin as shown in FIG. 1 and the metal particles contained in the brazing material are prevented from flowing into the circulating water. For the coating process and coating liquid composition, known techniques described in various patent documents can be used.

In this example, a pair of the resin tank bodies 4 are provided on both sides of the core 3, and as shown in FIG. 3, one of the resin tank bodies 4 is formed in a box shape with one open, and a stepped portion 4a that bulges outward at the opening edge. 1 and 2 and the circulating water inlet / outlet pipe 11 shown in FIGS. 1 and 2 is integrally formed on the side wall portion thereof. Further, a pair of boss portions 7 are formed to protrude from the side wall portion, and a female screw is threaded at the center thereof.
The boss portion 7 fixes the end portion of the airflow shroud 9 via the fastener 8 (see FIGS. 1 to 3). A fan (not shown) is disposed inside the shroud 9, and a leg portion of a fan motor (not shown) is fastened and fixed outside the opening of the shroud 9.
Further, as shown in FIG. 3, the stepped portion 4a of the tank body 4 is seated on the recess 2b of the header plate 2 via an O-ring 6, and the tank body 4 is bent by bending the claw portion 2a of the header plate 2. And the core 3 are fixed by caulking.

In this heat exchanger, high-temperature circulating water discharged from the fuel cell flows into the flat tubes 1 from one inlet / outlet pipe 11 through one resin tank body 4.
Cooling air generated by the fan's wind circulates on the outer surface side of the tube 1. After heat exchange is performed between the cooling air and the circulating water, the cooling air flows out from the opening of the shroud 9 as an example. The cooling air can also be circulated from the shroud 9 side to the core side.
The circulating water that has passed through the flat tube 1 flows out from the inlet / outlet pipe 11 of the other resin tank body 4 and circulates to the fuel cell.
When the tank is molded with PPA resin as in the present invention, even if it is exposed to high-temperature circulating water, ion elution is less likely to occur than conventional resins, and catalyst poisoning of the fuel cell is prevented as much as possible. Will be. At the same time, the strength is strong and the shroud can be supported.

Next, the resin tank body 4 is manufactured by injection-molding PPA resin. This resin material contains about 30% to 40% of glass fibers in the fibers of PPA.
A feature of the present invention is that a resin tank body 4 is manufactured using this PPA resin.
As shown in FIGS. 6 and 7, this PPA resin has higher physical durability (tensile strength and strain rate) against heat than PPS resins proposed in recent years, and can be said to be a good material for the tank portion. .

Next, it is desired that the metal ions inevitably remaining during the production of the resin material do not elute as much as possible in the circulating water as the material used for the heat exchanger for circulating fuel cell water.
As shown in FIG. 4, the inventor of the present invention measures the electrical conductivity of conventionally used resin materials and PPA resin materials and clarifies the degree of elution of the metal ions. Here, the conductivity means the conductivity (μS / cm) of pure water in which a resin material is immersed in pure water for a certain time.
In this experiment, PA66 (trade name: 66 nylon), PA66 and PA612 (612 nylon) synthetic fiber, each resin fiber containing 33% to 35% glass fiber in each resin of PPS and PPA, and pure water at 50 ° C. The conductivity after being immersed in 750 hours is measured.
As a result, it can be seen that PPA has the lowest conductivity, which is one-tenth of PA66, PPS, and a fraction of PA66 + PA612 synthetic fiber, and is the most suitable material for the tank material of the heat exchanger for fuel cell circulating water. It was confirmed that.
FIG. 5 is a result of comprehensive judgment as a resin tank of each material in consideration of the experimental result of FIG. 4, and shows the degree of goodness in the order of Δ → ○ → ◎.

As shown in FIG. 8, the heat exchanger 16 is disposed in the middle of the circulation path 14 including the fuel cell 12.
The circulation path 14 includes a heat exchanger 16, a fuel cell 12, a storage tank 13, a valve 17, and a pump P, and coolant for cooling the fuel cell circulates. Further, the fuel cell has a supply path for hydrogen and oxygen (not shown), and the produced water generated therein flows into the storage tank 13. Further, the pipe branches to the spraying device 15 through the valve 17 in the circulation path 14. This spraying device 15 is sprayed on the corrugated fins 10 of the heat exchanger 16 and the outer surface of the flat tube 1 to promote heat exchange.
On the back side of the heat exchanger 16, a shroud (not shown) is provided, and a fan 18 for raising air is disposed inside the shroud.

1 Flat tube 2 Header plate
2a Claw
2b Recess 3 Core 4 Resin tank body
4a Stepped part 5 Coating material 6 O-ring 7 Boss part

8 Fastener 9 Shroud
10 Corrugated fin
11 Entrance pipe
12 Fuel cell
13 Storage tank
14 Circuit
15 Spraying device
16 Heat exchanger
17 Valve
18 fans

Claims (4)

The flat tube (1) and the corrugated fin (10) are alternately arranged in parallel, both ends of the flat tube (1) are penetrated by the header plate (2), and the core (3) having the through-hole fixed thereto,
A fuel cell circulating water comprising a pair of resin tank bodies (4) each formed in a long and narrow box shape with one end opened, and the periphery of the header plate (2) being caulked and fixed to the outer periphery of the opening edge In heat exchangers for
A heat exchanger for circulating water in a fuel cell, wherein each resin tank body (4) is molded from polyphthalamide resin. The heat exchanger for circulating fuel cell water according to claim 1,
On the outer surface of each resin tank body (4), a plurality of shroud-fixing bosses (7) are provided so as to be separated from each other and integrally project, and the bosses (7) have a wind guide shroud (9). ) Is a heat exchanger for circulating water in a fuel cell in which the end of the fuel cell is fixed via a fastener (8). In the heat exchanger for circulating fuel cell water according to claim 1 or 2,
A heat exchanger for circulating water in a fuel cell, in which the flat tubes (1) are positioned in parallel in the horizontal direction and the resin tank body (4) is disposed on both sides of the core (3). The heat exchanger for circulating fuel cell water according to claim 3,
A fuel cell circulating water heat exchanger comprising a spraying device (15) for spraying at least part of the generated water generated by power generation of the fuel cell (12).

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