JP6986825B2 - How to store the fuel cell coolant container and fuel cell coolant - Google Patents

Description

The present invention relates to a fuel cell coolant container and a method for storing the fuel cell coolant using the container. More specifically, a fuel cell coolant accommodating container capable of maintaining the initial electrical conductivity with a small increase in the electric conductivity of the fuel cell coolant after storage and a fuel cell coolant using the same. Regarding the storage method of.

A fuel cell is generally configured as a stack having a structure in which a large number of single cells, which are power generation units, are stacked. Since heat is generated from the stack during power generation, a cooling plate is inserted every few cells to cool the stack. A coolant passage is formed inside the cooling plate, and the coolant flows through the passage to cool the stack.

The fuel cell coolant (hereinafter, simply referred to as “coolant”) circulates in the stack executing power generation to cool the stack. Therefore, when the electric conductivity of the coolant is high, the electricity generated in the stack flows to the coolant side and loses electricity, which reduces the power generation in the fuel cell. Therefore, pure water having low conductivity, in other words, high electrical insulation, is used as the conventional coolant. In addition, glycols or alcohols for preventing freezing are usually added to the coolant. When transporting and storing such an aqueous coolant, rust may occur in the metal container. In order to avoid this adverse effect, the coolant has conventionally been transported and stored in a resin container such as polyethylene.

The period from production to use of the coolant varies depending on the situation. For example, at dealers of vehicles equipped with fuel cells and automobile repair shops, the coolant is replenished as needed, so that the coolant is stocked. In such places, the period from the purchase of the coolant to the replenishment may be long, and as a result, the storage of the coolant may be extended for a long period of time. On the other hand, at a manufacturing site such as a vehicle equipped with a fuel cell, the coolant is usually used in a short period of time. However, from the viewpoint of cost and the like, it is desirable that the coolant can be stored for a long period of time.

In the process of studying the properties of the coolant after storage, the present inventors have newly confirmed that a phenomenon in which the electrical conductivity of the coolant increases during storage is observed. As a result, the present inventors have newly found that there is a technical problem that the power generation in the fuel cell may decrease due to the increase in the electric conductivity of the coolant due to the long-term storage of the coolant. rice field.

As a result of diligent research focusing on this technical problem, the present inventors have found that it is possible to suppress an increase in the electric conductivity of the coolant after storage by using a container having a specific configuration. , The present invention has been completed.

An object of the present invention is to provide a cooling liquid storage container capable of maintaining the initial electric conductivity with a small increase in the electric conductivity of the cooling liquid after storage, and a method for storing the cooling liquid using the same. do.

In order to achieve the above object, the present invention comprises a cooling liquid storage container having an inner layer made of a resin and a metal layer provided on the outer surface of the inner layer, and a method for storing the cooling liquid using the same. It is a summary.

According to the coolant accommodating container and the method for storing the coolant of the present invention, the decrease in the electric power generation of the fuel cell using the coolant is suppressed by suppressing the increase in the electric conductivity of the coolant after storage. be able to.

It is a figure which shows an example of the container of this invention. It is a figure which shows an example of the container of this invention. It is a figure which shows an example of the container of this invention. It is a figure which shows an example of the container of this invention. It is a figure which shows an example of the container of this invention.

Hereinafter, the coolant container and the method for storing the coolant of the present invention will be described in more detail. As described above, unless otherwise specified in the present specification, "coolant" means "fuel cell coolant".

An example of the coolant container of the present invention is shown in FIG. The container 1a of an example of the present invention has an inner layer 11 made of resin and a metal layer 12 provided on the outer surface of the inner layer 11.

The inner layer 11 is a layer facing the inside of the container 1, and the inner layer surface 111 is in contact with the coolant 2. The structure of the inner layer is not particularly limited as long as it does not inhibit the action and effect of the present invention. The inner layer may be one layer as shown in FIG. 1, or may be composed of two or more layers (11A and 11B in FIG. 2) as shown in FIG.

The type of resin constituting the inner layer is not particularly limited. The resin may be a homopolymer or a copolymer. Specifically, as the resin, for example, a polyolefin resin (for example, polyethylene, polypropylene), polystyrene, a polyester resin (for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN)), polychloride. Examples thereof include vinylidene, polyvinyl alcohol resin, polyamide, polyacrylonitrile, and polycarbonate. The polyethylene is high-density polyethylene (specific gravity 0.92 to 0.96, deflection temperature under load 130 ° C or less), low-density polyethylene (specific gravity 0.91 to 0.92, deflection temperature under load 100 ° C or less), ultra-low density polyethylene. It may be any of (specific gravity less than 0.9), linear low density polyethylene (specific gravity less than 0.94), and ultrahigh molecular weight (for example, molecular weight of 1 million or more) polyethylene.

The inner layer 11 is made of a resin material, but other components may be contained in the inner layer as long as the action and effect of the present invention are not impaired. Specific examples of the other component include known resin additives. Specific examples of the resin additive include antioxidants, light stabilizers, flame retardants, plasticizers, dyes, pigments and colorants.

The thickness of the inner layer 11 is not particularly limited as long as it does not hinder the action and effect of the present invention, and may be various thicknesses as needed. The thickness of the inner layer is usually 7 to 30 μm.

The metal layer 12 is a layer provided on the outer surface of the inner layer 11 (the surface opposite to the inner surface 111). The type of metal constituting the metal layer is not particularly limited. Specific examples of the metal include aluminum.

The structure of the metal layer is not particularly limited as long as it does not inhibit the action and effect of the present invention. Normally, the metal layer is one layer as shown in FIG. 1, but may be composed of two or more layers (12A and 12B in FIG. 3) as shown in FIG. Further, the thickness of the metal layer is not particularly limited as long as it does not hinder the action and effect of the present invention, and may be various thicknesses as needed. The thickness of the metal layer is usually 7 to 25 μm.

The means for forming the metal layer 12 on the outer surface of the inner layer 11 is not particularly limited. For example, a metal foil constituting the metal layer 11 may be formed, and then the metal foil may be bonded to the inner layer with an adhesive or another resin film having a heat-sealing property. Alternatively, the metal layer may be formed on the surface of the resin material (for example, a film-shaped or sheet-shaped resin material) constituting the inner layer by chemical vapor deposition, plasma vapor deposition, sputtering or the like.

Further, the order of forming the inner layer and the metal layer and forming the container is not particularly limited. As described above, a metal layer may be formed on one surface of a resin material and then used to manufacture a container. Alternatively, a hollow container may be manufactured in advance from a resin material by injection molding, blow molding, or the like, and then the metal layer may be formed on the outer surface of the hollow container by plasma vapor deposition or the like.

As long as the container of the present invention has the inner layer and the metal layer, the specific structure thereof is not particularly limited. An example of the container of the present invention is shown in FIGS. 1 to 5.

In the container 1a shown in FIG. 1, the inner layer 11 and the metal layer 12 are each one layer, and the metal layer 12 constitutes an outer layer (a layer in contact with the external environment).

In the container 1b shown in FIG. 2, the inner layer 11 has a multilayer structure (11A and 11B). Further, the metal layer 12 is one layer, which constitutes an outer layer. When the inner layer 11 has a multi-layer structure, the material constituting at least the innermost layer (the layer in contact with the fuel cell coolant, which corresponds to the inner layer 11A in FIG. 2) is a resin, unless the action and effect of the present invention are impaired. , The material constituting the inner layer is not particularly limited. Usually, each layer constituting the inner layer 11 is a resin layer. In this case, the resin material constituting each resin layer is not particularly limited. The resin layer may be the same resin material or different resin materials.

In the container 1c shown in FIG. 3, the metal layer 12 has a multi-layer structure (12A and 12B). When the metal layer has a multi-layer structure, the metal material constituting each metal layer is not particularly limited as long as the action and effect of the present invention are not impaired. The metal layer may be composed of different types of metal layers, or may be composed of the same type of metal layer.

In the container 1d shown in FIG. 4, the inner layer 11 has a multi-layer structure (11A and 11B), and the metal layer 12 has a multi-layer structure (12A and 12B). Regarding the inner layer 11 and the metal layer 12, the description regarding the containers 1B and 1C is valid.

The container 1e shown in FIG. 5 has another outer layer 13 on the outer surface of the metal layer 12. That is, the container of the present invention may have another outer layer on the outer surface of the metal layer. The material of the other outer layer is not particularly limited as long as it does not interfere with the action and effect of the present invention. The other outer layer is usually a resin layer. Specific examples of the resin constituting the resin layer include resins exemplified as the resin constituting the inner layer. The resin constituting the inner layer and the resin constituting the other outer layer may be the same resin or different resins. Examples of the combination of the resin constituting the inner layer and the resin constituting the other outer layer include a combination of a polyolefin resin and a polyester resin. In the container 1e shown in FIG. 5, the inner layer 11 is usually made of polyester resin and the other outer layer 13 is made of polyolefin resin, but the reverse is also possible.

As shown in FIG. 5A, the other outer layer may be a single layer, or may be a multilayer structure (13A and 13B) as shown in FIG. 5B. When the other outer layer has a multi-layer structure, the material constituting each layer is not particularly limited as long as the action and effect of the present invention are not impaired. Normally, each layer is a resin layer, but a combination of a resin layer and a metal layer may be used.

In the container of the present invention, when the inner layer, the metal layer, and the other outer layer have a multi-layer structure, the method of integrating each layer is not particularly limited. For example, the layers constituting the multilayer structure can be integrated with an adhesive or another resin film having a heat-sealing property. In this case, to be precise, an adhesive layer or a heat-sealing resin layer is formed between the layers constituting the multilayer structure, and FIGS. 1 to 5 show the description of such an adhesive layer or the heat-sealing resin layer. Is omitted. That is, the container illustrated in FIGS. 1 to 5 also includes an embodiment in which at least one of the layers of the multilayer structure has an adhesive layer or a heat-sealing resin layer.

The size of the container of the present invention is not particularly limited. The container of the present invention can be made into various sizes depending on the application.

In the storage method of the present invention, the coolant is stored in the container of the present invention. The "storage" of the present invention includes not only the case where the coolant is stored as it is (in a mode in which the coolant is not used as the coolant) (simple storage) but also the case where the coolant is stored while being used as the coolant (use storage). Including both. For example, the case where the container of the present invention is mounted on a vehicle together with a fuel cell for mounting on a vehicle and the coolant is stored while being used as the coolant is also included.

The storage method of the present invention is not particularly limited in the specific storage method and storage conditions as long as the cooling liquid is contained in the container of the present invention. As for the storage method and storage conditions, appropriate methods and conditions can be set as necessary. Further, the composition of the coolant is not particularly limited, and for example, a known coolant can be used. Specific examples of the coolant include water (ion-exchanged water and the like) or a coolant containing water (ion-exchanged water and the like) and glycols and / or alcohols.

The container and storage method of the present invention can be freely changed within the scope of the claims.

Hereinafter, the present invention will be specifically described with reference to Examples. The present invention is not limited to the embodiment shown in the examples. The embodiments of the present invention can be variously modified within the scope of the present invention according to the purpose, use and the like.

The composition of each container of Examples 1 and 2 and Comparative Example is shown in Table 1. The capacity of each container is 2 L. Container Example 1, the inner layer is PET (polyethylene terephthalate) 12 [mu] m, the metal layer is aluminum foil 9 .mu.m, the outer layer is composed of ONY (nylon) 15 [mu] m and LLDPE (linear low density polyethylene) 160 .mu.m (top the outer layer is LLDPE). The container of Example 1 was formed by laminating each layer by a dry laminating method. Containers Example 2, (PET the outermost layer is in contact with the LLDPE. Metal layer) to the inner layer PET12myuemu, the metal layer is aluminum, the outer layer is PET, ONY25myuemu and are composed of LLDPE180myuemu. The container of Example 2 was formed by using aluminum-deposited PET in which aluminum was vapor-deposited on PET (thickness 12 μm), and laminating the outer layer and each layer constituting the inner layer by a dry laminating method.

In each of the containers of Examples 1 and 2 and Comparative Example 1, 2 L of a fuel cell coolant (ethylene glycol / ion-exchanged water manufactured by CCI Co., Ltd.) was contained. Next, the coolant was stored under the condition of a temperature of 50 ° C., and the electric conductivity (μS / cm) after 168, 336, 504 and 672 hours was measured with a conductivity meter ES-12 (manufactured by HORIBA, Ltd.). .. The results are shown in Table 1.

From Table 1, it can be seen that the cooling liquid stored in the conventional resin container (comparative example) has an increased electric conductivity during storage. In particular, at 168 hours (7 days) after storage, the electrical conductivity has already increased about 4 times the initial value, and at 672 hours (28 days), it has increased up to 8 times the initial value. On the other hand, the coolant stored in the containers of Examples 1 and 2 contained in the container of the present invention still maintains the initial electrical conductivity even at 672 hours (28 days) after storage. Therefore, it can be seen that the container of the present invention is remarkably excellent in the effect of suppressing an increase in the electric conductivity of the cooling liquid during storage, and is suitable for storing the cooling liquid.

1a to 1e; fuel cell coolant container, 11; inner layer, 111; inner layer surface, 12; metal layer, 13; other outer layer, 2; fuel cell coolant.

Claims (4)

Inner layer thickness consisting of resin 7～30Myuemu, and contain coolant for the fuel cell to the fuel cell coolant storage container thickness provided on the outer surface has a metallic layer of 7~25μm of the inner layer However, a method for storing fuel cell coolant, which simply stores fuel cell coolant. The method for storing a fuel cell coolant according to claim 1, further comprising another layer on the outside of the metal layer. The method for storing a fuel cell coolant according to claim 1 or 2, wherein the resin is a polyolefin resin or a polyester resin. The method for storing a fuel cell coolant according to any one of claims 1 to 3, wherein the fuel cell coolant containing water or water and glycols and / or alcohols is contained.

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