KR20230098936A - Method for manufacturing fuel cell stack - Google Patents

Abstract

The present invention relates to a method for manufacturing a fuel cell stack, which can reduce a production defect rate and improve process speed while increasing an interfacial bonding force of a membrane-electrode assembly. The method for manufacturing a fuel cell stack comprises: a first step of manufacturing a fuel cell stack by stacking a plurality of fuel cells each including a membrane-electrode assembly, a pair of gas diffusion layers stacked on both sides of the membrane-electrode assembly, and a pair of separators stacked on the outer surface of each of the gas diffusion layers; and a second step of heating the membrane-electrode assembly by supplying heating gas to a cooling water passage surrounded by separators of the fuel cells stacked adjacent to each other in the first step.

Description

Method for manufacturing fuel cell stack {Method for manufacturing fuel cell stack}

The present invention relates to a method for manufacturing a fuel cell stack, and more particularly, to a method for manufacturing a fuel cell stack capable of reducing a production defect rate and improving a process speed while increasing interfacial bonding force of a membrane-electrode assembly.

In general, a fuel cell is a kind of power generation device that induces an electrochemical reaction using a fuel and an oxidizing agent and converts chemical energy into electrical energy through this.

These types of fuel cells are classified by their constituent materials and fuel. In the case of a polymer electrolyte membrane fuel cell (PEMFC), the electrolyte membrane separating the catalyst electrode layer passes hydrogen ions. made up of polymers.

In general, polymer electrolyte membrane fuel cells are composed of a laminated structure of unit cells composed of a membrane-electrode assembly (MEA), a gas diffusion layer (GDL), and a separator.

An electrochemical reaction for generating electricity in a fuel cell occurs in the membrane-electrode assembly. The membrane-electrode assembly is composed of an electrolyte membrane and a catalyst electrode layer bonded to both sides of the electrolyte membrane. The catalyst electrode layer is made of a catalyst and a polymer.

The structure of the membrane-electrode assembly varies depending on the application location or method of applying the catalyst electrode layer, but the final structure is a type in which both sides of the electrolyte membrane are in contact with the catalyst electrode layer. At this time, since the better the bonding state between the catalyst electrode layer and the electrolyte membrane, the better the performance and durability of the fuel cell. Therefore, a heat treatment process is added to the normal membrane-electrode assembly manufacturing process to increase the interfacial bonding force between the catalyst electrode layer and the electrolyte membrane by heating at a high temperature. .

In addition, when the membrane-electrode assembly exceeds the glass transition temperature through the heat treatment process, ion clusters are smoothly formed by rearrangement of the ionomer, thereby improving fuel cell performance.

Looking at the conventional membrane-electrode assembly heat treatment method, a single membrane-electrode assembly or a plurality of stacked membrane-electrode assemblies is subjected to high-temperature pressurization and heat treatment using a plate hot press. - There is a method of heat treatment by putting the electrode assembly in an oven in a roll form or a laminated form using protective paper.

The heat treatment method using the plate-type hot press is a method in which a plate heated to a specific temperature physically contacts the membrane-electrode assembly to transfer heat, and considering the characteristics of the membrane-electrode assembly made of a physically weak polymer, the defect rate is high. In addition, the heat treatment method using the oven is difficult to evenly control the temperature distribution in the oven, and the heat transfer method using the convection phenomenon has a disadvantage in that the required time is long.

In addition, the conventional heat treatment method as described above is difficult to apply to a roll-to-roll process, which is a continuous process of optimizing a membrane-electrode assembly, and may cause a bottleneck in mass production for mass production.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a fuel cell stack capable of reducing a production defect rate and improving a process speed while increasing the interfacial bonding force of a membrane-electrode assembly.

The object of the present invention is not limited to the above-mentioned object, and other objects of the present invention that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention provides a plurality of membrane-electrode assemblies, a pair of gas diffusion layers laminated on both sides of the membrane-electrode assembly, and a pair of separators laminated on the outer surfaces of each gas diffusion layer. A first step of manufacturing a fuel cell stack by stacking fuel cell cells of; A second step of heating the membrane-electrode assembly by supplying heating gas to a cooling water passage surrounded by separators of fuel cell cells stacked adjacent to each other in the first step; Provided is a fuel cell stack manufacturing method including a.

also,

According to the means for solving the above problems, the present invention provides the following effects.

First, a fuel cell stack is fabricated using a membrane-electrode assembly that has not been heat-treated, and then the membrane-electrode assembly is heat-treated by supplying hot air (ie, heating gas) at a predetermined temperature to the cooling water passage of the manufactured fuel cell stack. It is possible to increase the interfacial bonding force of the membrane-electrode assembly by implementing the effect, and since there is no separate physical contact for heat treatment of the membrane-electrode assembly, the resulting production defect rate can be reduced and the process speed is increased compared to the prior art. .

Second, the structure of the device for heat treatment of the membrane-electrode assembly is simple compared to the conventional heat treatment process, so maintenance costs are reduced, and the heat treatment process is performed in units of fuel cell stacks, not in units of membrane-electrode assemblies, so the effect of the manufacturing environment This is relatively reduced so that a separate environment control (eg, clean room) is not required, and cost reduction accordingly is possible.

Effects of the present invention are not limited to the effects mentioned above, and other effects of the present invention not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view schematically showing a cross-sectional structure of a general fuel cell stack;
2 is a view for explaining a process of heat-treating a membrane-electrode assembly in manufacturing a fuel cell stack according to an embodiment of the present invention.
3 is a graph showing the temperature change of the membrane-electrode assembly when the membrane-electrode assembly is heat-treated through the fuel cell stack manufacturing method according to an embodiment of the present invention.
4 is a view for explaining a process of heat-treating a membrane-electrode assembly in manufacturing a fuel cell stack according to another embodiment of the present invention.
5 is a view for explaining a process of heat-treating a membrane-electrode assembly in manufacturing a fuel cell stack according to another embodiment of the present invention.
6 is a view for explaining a process of heat-treating a membrane-electrode assembly in manufacturing a fuel cell stack according to another embodiment of the present invention.

Specific structural or functional descriptions presented in the embodiments of the present invention are merely exemplified for the purpose of explaining embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms.

In addition, throughout this specification, when a certain part "includes" a certain component, it means that it may further include other components, not excluding other components unless otherwise stated. .

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Matters represented in the accompanying drawings may be different from those actually implemented in the drawings schematically illustrated to easily explain the embodiments of the present invention.

In order to facilitate understanding of the present invention, first, a cross-sectional structure of a general fuel cell stack will be described with reference to FIG. 1 . 1 is a diagram schematically illustrating a cross-sectional structure of a general fuel cell stack.

In general, the fuel cell stack 100 has a structure in which a plurality of unit cells (ie, fuel cell cells) are stacked in one direction, and the fuel cell 101 is a membrane-electrode as shown in FIG. Composed of a pair of gas diffusion layers 120 stacked on both sides of the assembly 110 and the membrane-electrode assembly 110, and a pair of separator plates 130 stacked on the outer surfaces of each gas diffusion layer 120 do.

The pair of gas diffusion layers 120 are stacked on both sides of the membrane-electrode assembly 110 with the membrane-electrode assembly 110 at the center, and the pair of separators 130 are stacked on the membrane-electrode assembly 110. ) is stacked on the outer surface of the gas diffusion layer 120.

The separator 130 provides passages for a reaction gas for generating electricity and a coolant for cooling the fuel cell stack 100 and is configured to have a concave-convex cross-sectional structure as shown in FIG. 1 .

In the fuel cell stack 100, when a plurality of fuel cell cells 101 are stacked in one direction, the separator plates 130 of the fuel cell cells 101 adjacent to each other are stacked facing each other. A space surrounded by the plate 130 serves as a cooling water passage 131 , and a space between the separator plate 130 and the gas diffusion layer 120 serves as a reaction gas passage 134 .

In addition, the membrane-electrode assembly 110 is composed of an electrolyte membrane 111 and a pair of catalyst electrode layers 112 stacked on both sides of the electrolyte membrane 111, and is supplied through the reaction gas passage 134. Electricity is generated by the electrochemical reaction of the reactant gas.

The present invention relates to a method for manufacturing a fuel cell stack for increasing the performance and durability of a fuel cell by increasing the interfacial bonding force of a membrane-electrode assembly configured as above, and using a membrane-electrode assembly that has not been heat-treated. After manufacturing, by supplying hot air (ie, heating gas) to the cooling water passage of the fuel cell stack manufactured above, the effect of heat treatment of the membrane-electrode assembly is realized to increase the interfacial bonding force of the membrane-electrode assembly, and at the same time, compared to the conventional film - Reduce the production defect rate of electrode assembly and improve the process speed.

2 is a view for explaining a process of heat-treating a membrane-electrode assembly in manufacturing a fuel cell stack according to an embodiment of the present invention, and FIG. -This is a graph showing the temperature change of the membrane-electrode assembly when the electrode assembly is heat-treated.

4 is a view for explaining a process of heat-treating a membrane-electrode assembly in manufacturing a fuel cell stack according to another embodiment of the present invention, and FIGS. 5 and 6 are fuel cells according to another embodiment of the present invention. It is a drawing for explaining the process of heat-treating the membrane-electrode assembly during stack manufacturing.

In addition, the fuel cell stack manufactured by the manufacturing method of the present invention may have a cross-sectional structure as shown in FIG. can be explained

A fuel cell stack manufacturing method according to an embodiment of the present invention includes a membrane-electrode assembly 110, a pair of gas diffusion layers 120 stacked on both sides of the membrane-electrode assembly 110, and each gas diffusion layer ( 120) in a first step of manufacturing a fuel cell stack 100 by stacking in a row a plurality of fuel cell cells 101 composed of a pair of separator plates 130 stacked on the outer surface, and in the first step A second step of heating the membrane-electrode assembly 110 by injecting heating gas into the cooling water passage 131 surrounded by the separator 130 of the fuel cell 101 adjacent to each other is included.

The fuel cell stack 100 manufactured in the first step may be configured to have a cross-sectional structure as shown in FIG. 1, and a cooling water passage formed between neighboring fuel cell cells 101 surrounded by a separator 130. (131) is provided.

In addition, in the first step, after stacking a plurality of fuel cell cells 101, a pair of end plates (not shown) are stacked on the outside of the fuel cell disposed in the outermost layer, and the pair of end plates It may include a step of fixing the fuel cell cells 101 in a stacked state by combining fastening bands.

At this time, the fuel cell cells 101 are maintained in a stacked state by the surface pressure provided through the end plate, and the cooling water passage 131 and the reaction gas passage 134 of the separator 130 are kept airtight. . Although not shown, the separation plate 130 is provided with a sealing gasket (not shown) so that the passage is sealed by surface pressure of the end plate.

In the present invention, by injecting a gas heated to a predetermined temperature (ie, the heating gas) into the cooling water passage 131, the membrane-electrode assembly 110 is heated to implement a heat treatment effect.

In the first step, the fuel cell 101 and the fuel cell stack 100 are manufactured using a non-heat treated membrane-electrode assembly 110, and the membrane-electrode assembly 110 is cooled in the second step. It is heated by the heating gas injected into the flow path 131 . The interfacial bonding force of the membrane-electrode assembly 110 is increased by being heated in the second step.

As shown in FIG. 2 , in the embodiment of the present invention, the hot air generator 200 is used to supply heating gas to the cooling water passage 131 . The hot air generator 200 is a device configured to generate heating gas at a predetermined temperature, and supplies the heating gas to the cooling water passage 131 at a predetermined flow rate.

For example, the hot air generator 200 may supply the heating gas to the cooling water passage 131 at a predetermined flow rate by increasing the pressure of the heating gas using a gas compressor.

The hot air generator 200 may be connected to the inlet or outlet of the cooling water passage 131 through a connecting means so that gas can flow. The connection means has a structure in which the hot air generator 200 and the membrane-electrode assembly 110 can be easily connected and separated. It is used that is configured to maintain confidentiality so as not to leak.

In the embodiment of the present invention, the second step of heating the membrane-electrode assembly 110 includes connecting the hot air generator 200 to the cooling water passage 131 of the fuel cell stack 100, and the hot air generator ( 200) to supply the heating gas generated and discharged from the hot air generator 200 to the cooling water passage 131.

The hot air generator 200 is connected to at least one of the inlet and outlet of the cooling water passage 131 to supply heating gas to the cooling water passage 131 and to recover the heating gas discharged through the cooling water passage 131. For this purpose, it may be connected to the other one of the inlet and outlet of the cooling water passage 131.

As shown in FIG. 2 , when heating gas is supplied to the inlet of the cooling water passage 131 (ie, the cooling water inlet), the heating gas is discharged through the outlet of the cooling water passage 131 (ie, the cooling water outlet) to generate hot air. returned to generator 200. At this time, the heating gas supplied to the cooling water inlet 132 heats the membrane-electrode assembly 110 while passing through the inside of the fuel cell stack 100 through the cooling water passage 131 .

The heating gas passes through the membrane-electrode assembly 110 through the separator 130 surrounding the cooling water passage 131 and the gas diffusion layer 120 stacked between the separator 130 and the membrane-electrode assembly 110. transfers heat to That is, the thermal energy of the heating gas is transferred to the membrane-electrode assembly 110 by conduction.

The heating effect of the membrane-electrode assembly 110 using the heating gas can be confirmed through FIG. 3 . FIG. 3 shows a measurement of a temperature change of the membrane-electrode assembly when a temperature sensor is mounted at a location of the membrane-electrode assembly of the fuel cell stack and air heated to 65° C. is injected into the cooling water passage. At this time, the temperature of the air injected into the cooling water passage is only an experimental temperature selected to check the heating effect of the membrane-electrode assembly 110, whereby the hot air generator 200 supplied to the fuel cell stack 100 The temperature of the heating gas is not limited.

Referring to FIG. 3 , it can be confirmed that the membrane-electrode assembly is saturated to about 62° C. within 20 minutes by air (ie, heating gas) at 65° C. injected into the cooling water passage of the fuel cell stack.

In addition, since the gas diffusion layer 120 and the separator 130, which serve as a movement path for electrons generated in the membrane-electrode assembly 110, are formed of an electrically conductive material and generally have high thermal conductivity, the cooling water passage 131 The heating gas passing through can effectively heat the membrane-electrode assembly 110 through thermal conduction between the gas diffusion layer 120 and the separator 130 .

In addition, since the cooling water passage 131 is spatially isolated from the membrane-electrode assembly 110 and the gas diffusion layer 120 due to the structure of the fuel cell stack 100, the membrane-electrode assembly 110 by the pressure of the heating gas ) can prevent the physical transformation of

In order to effectively increase the interfacial bonding force of the membrane-electrode assembly 110, the temperature of the heating gas injected into the cooling water passage 131 is adjusted to the glass transition of the ionomer, which is one of the constituent materials of the membrane-electrode assembly 110. set above the temperature.

For example, in the case of a polymer electrolyte membrane fuel cell, Nafion, an ionomer, is used as a binder for the catalyst electrode layer 112 when manufacturing the membrane-electrode assembly 110, and the glass transition temperature of Nafion is 130 ° C. am. When Nafion is used as a binder of the membrane-electrode assembly 110, the heating gas supplied to the cooling water passage 131 is heated by considering the heat loss generated during flow from the hot air generator 200 to the fuel cell stack. (200) to a temperature higher than 130°C.

Specifically, the temperature of the heating gas injected into the cooling water passage 131 may be set to 100°C to 250°C. This is due to excessive heat treatment of the membrane-electrode assembly 110 when the minimum temperature of the heating gas for heat treatment of the membrane-electrode assembly 110 is 100 ° C and the temperature of the heating gas exceeds 250 ° C. This is because (100) is degraded and may adversely affect peripheral components constituting the fuel cell stack 100 (ie, peripheral components of the membrane-electrode assembly 110).

In general, in the case of a polymer electrolyte membrane fuel cell, water in the stack is absolutely necessary for driving the fuel cell stack. Accordingly, the fuel cell stack operates at a temperature of less than 100°C, and the membrane-electrode assembly uses an ionomer having a glass transition temperature of 100°C or higher.

Therefore, an ionomer having a glass transition temperature of less than 100°C is difficult to use in a membrane-electrode assembly of a polymer electrolyte membrane fuel cell, and in the present invention, the minimum temperature of the heating gas is set at 100°C.

In addition, the flow rate of the heating gas injected into the cooling water passage 131 may be set to 0.1 to 10 liters per minute (LPM). This is because when the flow rate of the heating gas is less than 0.1 LPM, sufficient heat cannot be transferred to the membrane-electrode assembly 110 due to insufficient flow rate of the heating gas, and the inlet 132 of the cooling water passage 131 into which the heating gas is injected. This is because a large variation in heat treatment effect may be caused at the outlet 133. In addition, when the flow rate of the heating gas exceeds 10 LPM, pressure rises in the cooling water passage 131 due to the excessive flow rate supply, and as a result, airtight parts of the fuel cell stack 100 may be damaged. In addition, when irreversible damage occurs to airtight parts of the fuel cell stack 100, problems may arise in driving the fuel cell stack 100 due to leakage of coolant.

Here, the flow rate of the heating gas injected into the cooling water passage 131 means the flow rate per fuel cell 101 .

Meanwhile, since the heating gas supplied from the hot air generator 200 to the fuel cell stack 100 flows in one direction through the cooling water passage 131 between the cooling water inlet 132 and the cooling water outlet 133, the flow of the heating gas When the length of the fuel cell stack 100 based on the direction is long or the heat loss due to the outdoor temperature is low, the temperature of the heating gas injected into the cooling water passage 131 and the discharge from the cooling water passage 131 are large. A difference may occur between the temperatures of the heating gas being heated.

That is, the heating gas flowing in one direction within the fuel cell stack 100 may be gradually cooled and reduced in temperature while passing through the stack 100, and accordingly, the heating gas injected into the stack 100 and discharged from the stack 100 A temperature difference may occur between the heating gases being heated. When the above temperature difference occurs, a situation in which the membrane-electrode assembly 110 is heated unevenly may occur.

In order to minimize the temperature difference, the flow direction of the heating gas may be periodically changed when supplied to the fuel cell stack 100 . Specifically, when the heating gas is supplied to the cooling water passage 131 through one of the cooling water inlet 132 and the cooling water outlet 133, the other of the cooling water inlet 132 and the cooling water outlet 133 passes a predetermined time. It may be supplied to the cooling water passage 131 through one side.

In other words, the heating gas is injected into the cooling water passage 131 through one of the cooling water inlet 132 and the cooling water outlet 133, and the injection position of the heating gas may be periodically changed. By changing the injection position of the heating gas, the flow direction of the heating gas in the cooling water passage 131 is changed.

To this end, as shown in FIG. 4 , a hot air distributor 210 may be installed between the hot air generator 200 and the fuel cell stack 100 to control the flow direction of the heating gas. That is, the heating gas discharged from the hot air generator 200 may be supplied to the fuel cell stack 100 through the hot air distributor 210 .

The hot air distributor 210 is configured to change the flow direction of the heating gas supplied from the hot air generator 200 to the fuel cell stack 100 .

For example, the hot air generator 200 is connected to the cooling water inlet 132 and the cooling water outlet 133 of the fuel cell stack 100 through the hot air distributor 210 . At this time, the hot air distributor 210 is fluidly connected to the outlet 201 and the inlet 202 of the hot air generator 200, and at the same time, the cooling water inlet 132 and the cooling water outlet 133 of the fuel cell stack 100 ) is fluidly connected to.

The hot air distributor 210 injects the heating gas discharged from the outlet 201 of the hot air generator 200 into one of the cooling water inlet 132 and the cooling water outlet 133, and the internal flow path for the flow of the heating gas It is possible to change the injection position of the heating gas and change the flow direction of the heating gas in the fuel cell stack 100 by periodically changing the .

When the heating gas is injected into the cooling water inlet 132, it flows through the cooling water passage 131 from the cooling water inlet 132 toward the cooling water outlet 133 (refer to the left view of FIG. 4 ), and flows toward the cooling water outlet 133. When injected, it flows from the cooling water outlet 133 toward the cooling water inlet 132 through the cooling water passage 131 (refer to the right side view of FIG. 4 ).

Meanwhile, in order to increase the efficiency of the heat treatment process, as shown in FIG. 5 , heating generated by one hot air generator 200 in a plurality of fuel cell stacks 100 in which cooling water passages 131 are fluidly connected in series is possible. It is also possible to supply gas.

At this time, the outlet 201 of the hot air generator 200 is connected to the cooling water inlet 132 or the cooling water outlet 133 of the fuel cell stack 100 disposed at the front of the plurality of fuel cell stacks 100, In the plurality of fuel cell stacks 100, one of the cooling water inlet 132 and the cooling water outlet 133 is fluidly connected to each other.

Accordingly, the heating gas generated and discharged from the hot air generator 200 sequentially passes from the fuel cell stack 100 disposed at the front to the fuel cell stack 100 disposed at the rear, while the film inside the fuel cell stack 100 - The electrode assembly 110 is heated.

To this end, the second step of heating the membrane-electrode assembly 110 in the embodiment of the present invention is the step of connecting the cooling water passages 131 of the plurality of fuel cell stacks 100 in series so as to allow fluid movement, the above Connecting an outlet 201 of a hot air generator 200 generating the heating gas to a coolant passage of a fuel cell stack disposed at the frontmost side of the plurality of fuel cell stacks 100, and the hot air generator 200 The heating gas generated and discharged from the hot air generator 200 may be driven and supplied to the cooling water passage of the fuel cell stack disposed at the forefront.

In addition, the second step further includes connecting the inlet 202 of the hot air generator 200 to the coolant passage of the fuel cell stack disposed at the rearmost of the plurality of fuel cell stacks 100, thereby making the fuel cell fuel cell The heating gas passing through the stack 100 can be recovered.

Also, as shown in FIG. 6 , the hot air generator 200 may be connected in parallel to the cooling water passages 131 of the plurality of fuel cell stacks 100 so as to be able to supply fluid. At this time, the heating gas discharged from one hot air generator 200 may be distributed and simultaneously supplied to the plurality of fuel cell stacks 100, and the heating gas discharged through the plurality of fuel cell stacks 100 is collected and It can be recovered by the hot air generator 200.

To this end, the second step of heating the membrane-electrode assembly 110 in the embodiment of the present invention is the step of connecting the cooling water passages 131 of the plurality of fuel cell stacks 100 in parallel so as to allow fluid movement, the above Connecting the outlet 201 of the hot air generator 200 generating the heating gas to one end (ie, inlet or outlet) of the cooling water passage 131 connected in parallel, and driving the hot air generator 200 and supplying the heating gas generated and discharged from the hot air generator 200 to the cooling water passage 131 connected in parallel.

In addition, the second step further includes connecting the inlet 202 of the hot air generator 200 to the other end (ie, outlet or inlet) of the cooling water passage 131 connected in parallel to the fuel cell. The heating gas passing through the stack 100 can be recovered.

Since the embodiments of the present invention have been described in detail above, the terms or words used in the present specification and claims should not be construed as being limited to a conventional or dictionary meaning, and the scope of the present invention is not limited to the above-described embodiments. It is not limited to examples, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also included in the scope of the present invention.

100: fuel cell stack 101: fuel cell cell
110: membrane-electrode assembly 111: electrolyte membrane
112: catalyst electrode layer 120: gas diffusion layer
130: separator 131: coolant flow path
132: cooling water inlet 133: cooling water outlet
134: reaction gas flow path 200: hot air generator
201: outlet 202: inlet
210: hot air distributor

Claims (9)

A fuel cell stack is formed by stacking a plurality of fuel cell cells composed of a membrane-electrode assembly, a pair of gas diffusion layers stacked on both sides of the membrane-electrode assembly, and a pair of separator plates stacked on the outer surface of each gas diffusion layer. The first step of manufacturing;
a second step of heating the membrane-electrode assembly by supplying a heating gas to a cooling water passage surrounded by separators of fuel cell cells stacked adjacent to each other in the first step;
A fuel cell stack manufacturing method comprising a.
The method of claim 1,
In the second step, a heating gas having a predetermined temperature is injected into one of the inlet and outlet of the cooling water passage, and the injection position of the heating gas is periodically changed.
The method of claim 1,
The fuel cell stack manufacturing method, characterized in that the temperature of the heating gas injected into the cooling water passage is higher than the glass transition temperature of the ionomer, one of the materials constituting the membrane-electrode assembly.
The method of claim 1,
The fuel cell stack manufacturing method, characterized in that the temperature of the heating gas injected into the cooling water passage is 100 ℃ ~ 250 ℃.
The method of claim 1,
The fuel cell stack manufacturing method, characterized in that the flow rate of the heating gas injected into the cooling water passage is 0.1 LPM (liter per minute) to 10 LPM.
The method of claim 1,
The second step is:
a) connecting cooling water passages of a plurality of fuel cell stacks in series in a fluid flow manner;
b) connecting an outlet of a hot air generator generating the heating gas to a cooling water flow path of a fuel cell stack disposed at the frontmost side of the plurality of fuel cell stacks;
c) supplying the heated gas generated and discharged from the hot air generator to a cooling water passage of the fuel cell stack disposed at the frontmost side by driving the hot air generator;
A fuel cell stack manufacturing method comprising a.
The method of claim 6,
The second step further comprises connecting an inlet of the hot air generator to a cooling water passage of a fuel cell stack disposed at the rearmost of the plurality of fuel cell stacks.
The method of claim 1,
The second step is:
a) connecting cooling water passages of a plurality of fuel cell stacks in parallel in a fluid flow manner;
b) connecting an outlet of a hot air generator generating the heating gas to one end of the cooling water passages connected in parallel;
c) driving the hot air generator to supply the heated gas generated and discharged from the hot air generator to the cooling water passages connected in parallel;
A fuel cell stack manufacturing method comprising a.
The method of claim 8,
The second step further comprises connecting the inlet of the hot air generator to the other end of the cooling water flow path connected in parallel.

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