JP2006298670A - Method and apparatus for generating hydrogen and method and system for generating electrochemical energy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for generating a sufficient amount of hydrogen with good efficiency, safety and good controllability and to provide a method and a system for generating electrochemical energy. <P>SOLUTION: A water pouring pipe 3 introduced from a water storage chamber 2 is inserted in a storage chamber 1 (housing portion) to house the mixed powder 7 of a hydride powder and an acid matter powder. Hydrogen (H<SB>2</SB>) generated by pouring water in the storage chamber 1 is automatically sent to a fuel cell 4 (an electrochemical device) through a hydrogen supplying pipe 6 by its inner pressure rising. A water storage 5 to recover generated water (H<SB>2</SB>O) is set at the oxygen electrode side of the fuel cell 4 and then water is returned from the water storage 5 to the water storage chamber 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydrogen generation method and apparatus suitable for a fuel cell, for example, and an electrochemical energy generation method and system thereof.

  Recently, the need for an alternative clean energy source that can replace fossil fuels such as oil has been screamed, and for example, hydrogen (gas) fuel has attracted attention. Hydrogen is an ideal energy source that is clean and inexhaustible because it contains a large amount of chemical energy per unit mass and does not release harmful substances, global warming gases, or the like when used.

  In recent years, fuel cells that can extract electric energy from hydrogen energy have been actively developed, and are expected to be used as large-scale power generation, on-site private power generation, and as a power source for electric vehicles. ing. In recent years, small fuel cells suitable for applications such as cellular phones and notebook personal computers have been actively developed due to the convenience of simply replacing the fuel and not requiring charging.

  Such fuel cells include, for example, a solid polymer type, a phosphoric acid type, a carbonated molten salt type, and a solid oxide type. Among them, a solid polymer fuel cell has an operating temperature of room temperature ( 25 [deg.] C.) to 100 [deg.] C. or less, and is attracting attention because it is lower than others.

  In this polymer electrolyte fuel cell, for example, a fuel electrode (for example, a hydrogen electrode) and an oxygen electrode are disposed with a polymer electrolyte membrane having a sulfonic acid group or a phosphoric acid group interposed therebetween, and a fuel (hydrogen) is placed on these electrodes. ) Or oxygen, the hydrogen ions (protons) generated from the fuel electrode reach the oxygen electrode through the polymer electrolyte membrane, and the hydrogen ions and oxygen react on the oxygen electrode catalyst to produce water. An electromotive force is obtained by causing the generated redox reaction.

  FIG. 6 schematically shows an example of the configuration of the polymer electrolyte fuel cell 64 (see Patent Document 1 described later).

  That is, a negative electrode (fuel electrode or hydrogen electrode) 51 and a positive electrode (oxygen electrode) 54 with a terminal 59 and a terminal 58, which are in close contact or dispersed with each other, face each other, and the proton conductor 52 is sandwiched between these two electrodes. Has been.

In use, on the negative electrode 51 side, hydrogen (H ₂ ) is supplied from the hydrogen gas generator 60 through the inlet 61 and passes through the gas flow path 56 (this may not be provided). A part of it is discharged. At this time, hydrogen as fuel contacts the negative electrode 51 while passing through the gas flow path 56, and protons (H ⁺ ) and electrons e are generated by the oxidation reaction.

Among them, the protons generated, moves to the positive electrode 54 side together with protons generated in the proton conductor within 52 where, O ₂ or air toward the discharge port 57 is supplied to the gas passage 55 through the inlet 53 Is reduced by electrons, and the generated oxygen ions and protons react to generate water (H ₂ O), which is discharged from the outlet 57.

  At this time, the electrons e generated when hydrogen as a fuel comes into contact with the negative electrode 51 move from the terminal 59 to the terminal 58, but a desired electromotive force is obtained by a load provided between the terminal 59 and the terminal 58. be able to. Note that current or voltage can be measured by connecting an ammeter and a voltmeter between the terminals 59 and 58.

The above chemical reaction (battery reaction) can be expressed by the following reaction formula.
Negative side:
2H ₂ → 4H ⁺ + 4e
Positive side:
O ₂ + 4H ⁺ + 4e → 2H ₂ O

  Examples of the storage or supply method of hydrogen supplied to the negative electrode of the fuel cell include, for example, a high-pressure cylinder method for storing in a high-pressure cylinder, a liquid hydrogen method for liquefying hydrogen and storing it in a cylinder, and storing in a hydrogen storage alloy. Examples thereof include an occlusion alloy method and a gas reforming method in which hydrogen is extracted by reforming natural gas or methanol.

  However, these methods have various drawbacks. First, in the high pressure cylinder system, the amount of hydrogen per weight obtained as a result is small due to the cylinder weight.

  Further, in the liquid hydrogen system, although this point is improved, cooling (for example, −253 ° C.) equipment and energy for liquefying hydrogen are required.

  Further, in the occlusion alloy system, heating is required for actual hydrogen extraction, and the hydrogen occlusion amount itself is low.

  In addition, the gas reforming system does not have these problems, but it requires a reformer that requires heating, and poisoning of the catalyst due to impurities such as carbon monoxide contained in the generated hydrogen. .

  As a hydrogen supply system different from the above-described systems, there is a system in which a hydride is dissolved in a basic aqueous solution and hydrogen is extracted by injecting an acidic aqueous solution into this solution (see Patent Document 2 described later).

  Alternatively, there is one in which an acidic aqueous solution is brought into contact with a solid hydride to extract hydrogen (see Patent Document 3 described later).

Both of these two hydrogen supply systems utilize the following hydrolysis reaction (here, NaBH ₄ is used as a hydride).
NaBH ₄ + 2H ₂ O → NaBO ₂ + 4H ₂
It is.

JP 2004-83318 A (page 15, line 9 to line 17, FIG. 8) JP 2004-83318 A (page 9, line 13 to page 10, line 43, FIGS. 1 and 2) and JP 2004-244262 (page 5, line 45 to page 6, page 12). Line, Fig. 1) JP 2003-146604 A (page 6, right column, line 10 to page 7, left column, line 14; FIG. 1)

  However, in the hydrogen supply method according to Patent Documents 2 and 3 described above, in the former (Patent Document 2), in order to dissolve the hydride in the basic aqueous solution, it is possible to store the hydride beyond the limit of its dissolution concentration. Can not. Therefore, in order to obtain more hydrogen, the storage container for the solution has to be enlarged, and there is a limit to install it in the engine part of a vehicle having limited space.

  In addition, due to the strong basicity of the solution, there is a difficulty in handling safety. For example, when a basic substance (alkali substance) is bubbled when hydrogen is generated, the basic substance mixed in the generated hydrogen is deactivated by neutralizing the proton conductor (for example, Nafion membrane) in the fuel cell. There is a fear. In addition, a sufficient protection mechanism is necessary to prevent the leakage of each aqueous solution, etc., resulting in poor handling safety.

  On the other hand, in the latter (Patent Document 3), since a solid hydride is used, problems such as the limit of the amount of hydride stored are unlikely to occur. However, since an acidic aqueous solution is used, the handling safety against liquid leakage is still necessary. Sufficient protection mechanism is required to ensure the safety.

  And since any supply system mentioned above uses aqueous solution, the controllability of the amount of generated hydrogen is not so good.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a hydrogen generation method and apparatus capable of generating hydrogen in a sufficient amount efficiently, safely and with good controllability, and An object of the present invention is to provide an electrochemical energy generation method and system.

  That is, the present invention relates to a hydrogen generation method in which hydrogen is generated by supplying water to a solid mixture of a solid hydride and a solid acid.

  The present invention also provides a hydrogen generation unit for use in the implementation of the hydrogen generation method, comprising a storage unit for mixed solids of solid hydride and solid acid, and water supply means for supplying water to the storage unit. It relates to the device.

  The present invention also relates to a method of generating electrochemical energy using an electrochemical energy generation system comprising an electrochemical device using hydrogen as a raw material and a hydrogen generator, and mixing a solid hydride and a solid acid. The present invention relates to a method for generating electrochemical energy, characterized in that hydrogen generated by supplying water to a solid material is led to the electrochemical device.

  The present invention further relates to an electrochemical energy generation system comprising an electrochemical device using hydrogen as a raw material and a hydrogen generator, wherein the hydrogen generator accommodates a solid mixture of solid hydride and solid acid. And a water supply means for supplying water to the housing part, characterized in that hydrogen introduction means for introducing hydrogen generated in the hydrogen generation apparatus to the electrochemical device is provided. The present invention relates to an electrochemical energy generation system.

  According to the present invention, since hydrogen is generated by supplying water to a solid mixture of a solid hydride and a solid acid, a hydride or an acid is added to an aqueous solution as in the conventional example described above. Compared to the case of using dissolved substances, a larger amount of hydride is accommodated in the accommodating part, and hydrogen can be generated efficiently (with low energy) in a sufficient amount while being small in size, and liquid leakage It is possible to ensure safety in handling, and to generate hydrogen with good controllability by controlling the amount of water supplied.

  In the present invention, it is desirable to mix the acid with 1 to 50% by weight of the mixed solid with the hydride. For example, if the acid content is less than 1% by weight, a sufficient catalytic effect (according to the above-described hydrolysis reaction) of the acid compound cannot be obtained, and the amount of hydrogen generated becomes poor. This is because if the amount exceeds 50% by weight, the proportion of hydride in the mixed solid decreases, so that the amount of hydrogen generated becomes poor.

  Further, in order to efficiently generate a desired sufficient amount of hydrogen, it is desirable to supply 3 to 20 ml / min of the water per 1 g of the mixed solid.

In addition, as the hydride,
General formula:
MH _4-n , M (BH ₄ ) _4-n or M (AlH ₄ ) _4-n
(However, M is an alkali metal of Group 1A of the periodic table, an alkaline earth metal of Group 2A of the periodic table, a metal of Periodic Table 1B, 2B, 3A, 4A, 5A, 6A or 7A, boron Or it is aluminum and n is an integer of 0-3.)
It can be used using a compound represented by:

In this case, the hydride of the general formula: LiH contained _{MH 4-n, NaH, KH} , MgH 2, CaH 2, TiH 2, ZrH 2, CrH 3, MoH 3, FeH 3, FeH 2, CoH, CoH ₂ , NiH ₂ , CuH, AgH, ZnH ₂ , BH _3, AlH _{3 and the} like; LiBH ₄ , NaBH ₄ , KBH ₄ , Mg (BH ₄ ) ₂ , Ca contained in the general formula M (BH ₄ ) _4-n (BH ₄ ) ₂ , Ba (BH ₄ ) ₂ , Sr (BH ₄ ) ₂ and Fe (BH ₄ ) ₂ etc .; General formula: LiAlH ₄ , NaAlH ₄ and KAlH ₄ contained in M (AlH ₄ ) _4-n Etc .; and at least one selected from the group consisting of:

  In addition, as the acidic substance, an organic solid acid or an inorganic solid acid such as a sulfate, a phosphorus oxide, or a chloride can be used.

In this case, the acidic substance is an organic solid acid such as oxalic acid, (+)-L-ascorbic acid, citric acid, etc., and inorganic solid acids such as NiSO ₄ , CuSO ₄ , AlPO ₄ , ZnCl ₂ and CuCl _2. And at least one selected from the group consisting of:

  In the present invention, a mixture of a solid hydride and a solid acidic substance is used to obtain water by supplying water to the solid substance. For example, whether the hydride and the acidic substance are mixed in a powder state. Alternatively, the mixed powder may be molded and used, and the water may be dropped or sprayed.

  The present invention is suitable for configuring the electrochemical device as a fuel cell, and in order to reuse the water generated in the oxygen electrode (omitting or reducing the storage space), in particular, the water generated in the oxygen electrode. Is preferably refluxed to the water supply means of the hydrogen generator.

  Next, a preferred embodiment of the present invention will be described in detail with reference to FIGS.

According to this embodiment, for example, a solid hydride powder having hydrolyzability such as sodium borohydride (NaBH ₄ ) and a solid acid powder such as oxalic acid (COOH) ₂ are mixed. Water (H ₂ O) is injected into the mixed powder and hydrogen (H ₂ ) is generated based on the above-described reaction.

Here, the solid hydride refers to a compound having a property of generating hydrogen (H ₂ ) and an oxide such as NaBO ₂ by hydrolysis when brought into contact with water. As the compound having this property, metal hydrides, borohydride metals and aluminum hydride metals represented by the following general formula 1, formula 2 and formula 3 can be used.
General formula:
MH _4-n ...... Formula 1, M (BH ₄ ) _4-n ...... Formula 2, M (AlH ₄ ) _4-n ...... Formula 3
(However, M is an alkali metal of Group 1A of the periodic table, an alkaline earth metal of Group 2A of the periodic table, a metal of Periodic Table 1B, 2B, 3A, 4A, 5A, 6A or 7A, boron Or it is aluminum and n is an integer of 0-3.)

As examples of the general formula 1, LiH, NaH, KH, MgH 2, CaH 2, TiH 2, ZrH 2, CrH 3, MoH 3, FeH 3, FeH 2, CoH, CoH 2, NiH 2, CuH, AgH, ZnH ₂ , metal hydrides such as BH ₃ and AlH ₃ are exemplified.

Examples of the general formula 2 include LiBH ₄ , NaBH ₄ , KBH ₄ , Mg (BH ₄ ) ₂ , Ca (BH ₄ ) ₂ , Ba (BH ₄ ) ₂ , Sr (BH ₄ ) ₂ , Fe (BH _{4). 2} ) Metal borohydride such as ₂ .

Furthermore, examples of the general formula 3 include aluminum hydride metals such as LiAlH ₄ , NaAlH ₄ , and KAlH ₄ .

  The choice of hydride may be determined from the compounds listed above, but from the industrial point of view, it is ultimately determined from multipoint requirements such as the amount of hydrogen generated, cost and safety. Is desirable.

On the other hand, the solid acidic substance refers to a substance whose surface shows acidity, and is not particularly limited. For example, oxalic acid which is an organic solid acid, (+)-L-ascorbic acid, citric acid and the like Inorganic solid acids such as NiSO ₄ and CuSO ₄ , sulfur oxides such as AlPO ₄ , phosphorus oxides such as ZnCl ₂ and CuCl _{2, and the} like.

  In the present embodiment, each powder of solid hydride and solid acid is mixed to form a powder (or a pressure-molded state), and water is poured into the powder. The droplets may be left as they are, or sprayed and sprayed.

In this way, for example, hydrogen can be generated by the following hydrolysis reaction and taken out to the target location. In this reaction, the solid acidic substance does not directly generate hydrogen but has a catalytic function for promoting the hydrolysis reaction of the hydride.
NaBH ₄ + 2H ₂ O → NaBO ₂ + 4H ₂

  Moreover, about the mixing ratio of a hydride and an acidic substance, it is desirable to mix a solid acidic substance in the range of 1 to 50 weight% of a mixed solid substance. That is, if the amount of the solid acid is less than 1% by weight, the amount as a catalyst is too small, so that a sufficient catalytic effect cannot be obtained, the amount of hydrogen generated is poor, and the solid acid is less than 50% by weight. If it exceeds, the proportion of hydride decreases, so the amount of hydrogen generated tends to decrease.

  Therefore, the mixing ratio between the hydride and the acid is preferably 1 to 50% by weight of the solid acid and more preferably 10 to 30% by weight of the mixed solid.

  In order to sufficiently generate hydrogen in a desired amount, it is desirable to supply the water at a rate of 3 to 20 ml / min per 1 g of the mixed solid. That is, if the water supply rate is less than 3 ml / min, the amount of water required for the reaction is small, so that the amount of hydrogen generation is significantly reduced. If the water supply rate exceeds 20 ml / min, This is because the generation amount is sufficient, but the generation amount is saturated and does not improve.

  According to the present embodiment, since hydrogen is generated by supplying water to a solid mixture of solid hydride and solid acid, the hydride is added to the aqueous solution as in the conventional example described above. Or, a larger amount of hydride can be accommodated in the accommodating portion, compared with the case where the acidic substance is dissolved, and hydrogen can be generated efficiently (with low energy) in a sufficient amount while being small, and Safety in handling without leakage etc. can be ensured, and hydrogen can be generated with good controllability by controlling the amount of water supplied.

  In applications where water is generated during use, such as fuel cells, the water storage space can be omitted or reduced if the generated water is recovered and reused in the hydrolysis reaction.

  In other words, since it is possible to fill a larger amount of mixed solids of hydride and solid acid corresponding to the amount of water storage space can be reduced, the amount of generated hydrogen is significantly increased, so that it can be used in portable devices and the like. This is a great advantage. Therefore, according to the present embodiment, it is possible to provide a fuel cell having a much longer operating time than the conventional example described above. Moreover, hydrogen can be obtained at normal temperature and a simple system can be constructed.

  FIG. 1 shows a structure of an electrochemical energy generation system 30 using a solid polymer fuel cell and a hydrogen generation method.

A water injection pipe 3 led from the water storage chamber 2 is inserted into the storage chamber 1 (accommodating portion) in which the mixed powder 7 of hydride powder and acidic powder is stored. Hydrogen (H ₂ ) generated in the storage chamber 1 is automatically supplied to the fuel cell 4 (electrochemical device) through the hydrogen supply pipe 6 due to an increase in internal pressure due to the generated hydrogen gas. Further, it is preferable that a water storage section 5 for collecting generated water (H ₂ O) generated is provided on the oxygen electrode side of the fuel battery cell 4.

  The mixed powder 7 of the hydride powder and the acid powder is disposed on the bottom of the storage chamber 1, and the water injection pipe 3 extending from the water storage chamber 2 penetrates the lid 8 that closes the upper portion of the storage chamber 1 and stores the storage chamber. 1 is used to pour water into the mixed powder 7 in the storage chamber 1. The water storage unit 5, the water storage chamber 2 and the water injection pipe 3 constitute a water supply means, and the water storage chamber 2, the water injection pipe 3 and the storage chamber 1 constitute a hydrogen generation unit 24.

Hydrogen (H ₂ ) generated in the storage chamber 1 is sent to the fuel electrode side of the fuel cell 4 through the hydrogen supply pipe 6 (hydrogen introduction means). The hydrogen supply pipe 6 penetrates the lid 8 located at the upper part of the storage chamber 1 and enters the storage chamber 1 and is used to supply hydrogen from the storage chamber 1 into the fuel cell 4.

  The generated water discharged from the oxygen electrode side of the fuel battery cell 4 is once stored in the water storage unit 5, then returned to the water storage chamber 2, and passed through the water injection pipe 3 into the water storage chamber 1 for hydrolysis reaction. As used again.

In such a structure and hydrogen generation method, for example, a hydrolyzable solid hydride such as sodium borohydride (NaBH ₄ ) and a solid acid such as oxalic acid (COOH) ₂ are mixed. Water (H ₂ O) is injected into the mixed solid thus produced, and hydrogen can be generated and removed by the hydrolysis reaction described above.

  As shown in FIGS. 2 and 3, the fuel cell 4 basically has a fuel electrode 21 and oxygen on both surfaces of a polymer electrolyte membrane 20 (proton conductor) having hydrogen ion (proton) conductivity, respectively. It has an electrode-membrane assembly 23 (MEA: Membrane Electrode Assembly) in which the electrode 16 is bonded. When hydrogen is supplied to the fuel electrode 21 side and oxygen or air is supplied to the oxygen electrode 16 side, the above-described cell reaction occurs, and electrons e move from the fuel electrode 21 to the oxygen electrode 16 through the load. Electromotive force is generated.

  Any polymer electrolyte membrane 20 may be used as long as it has hydrogen ion conductivity. For example, a hydrogen ion conductive polymer material such as perfluorosulfonic acid resin (trade name Nafion, manufactured by DuPont) can be cited, and other hydrogen ion conductors include polystyrene sulfonic acid and sulfone. Polymer materials such as fluorinated polyvinyl alcohol can be used.

  In addition, the fuel electrode 21 and the oxygen electrode 16 are made of, for example, a catalyst in which platinum or a platinum alloy as a metal having catalytic ability is fixed to a carbon powder such as acetylene black or activated carbon, as a carbon sheet, carbon cloth, or the like. It is made by applying to a conductive porous substrate.

  The electrode-membrane assembly 23 is sandwiched between the cell casing 19a on the fuel electrode 21 side and the cell casing 19b on the oxygen electrode 16 side. Between these, the mixture of oxygen and hydrogen is prevented and electrode crushing is prevented. In order to prevent this, a gasket 12a is sandwiched between the fuel electrode 21 side and a gasket 12b is sandwiched between the oxygen electrode 16 side.

Here, the cell casing 19a on the fuel electrode 21 side has, on its outer surface side, a lower connection port 17d for taking in hydrogen (H ₂ ) and an upper connection port 17c for discharging unused hydrogen. In addition, on the inner surface side, a groove 15 a as a hydrogen gas flow path is formed in a meandering shape so that hydrogen can sufficiently contact the fuel electrode 21.

The cell casing 19b on the oxygen electrode 16 side has an upper connection port 17a for taking in oxygen (O ₂ ) or air on the outer surface side, and water (H ₂₎ generated by a reaction in the fuel cell. And a lower connection port 17b for discharging O), and a groove 15b as a flow path of oxygen or air is provided on the inner surface side so that oxygen or air sufficiently contacts the oxygen electrode 16. It is formed in a serpentine shape so that it can be made.

  Further, the cell casing 19a, the gasket 12a, the electrode-membrane assembly 23, the gasket 12b, and the cell casing 19b are fixed by passing the bolts 18 through the screw holes 13 provided at the four corners in common. Can be integrated.

In the fuel battery cell 4, the battery reaction described above occurs during use. That is, on the fuel electrode 21 side, hydrogen is supplied from the hydrogen gas generator 24 through the supply pipe 6 and the connection port 17d, and part of the hydrogen is discharged from the connection port 17c through the groove 15a. At this time, while hydrogen as a fuel passes through the groove 15a, it comes into contact with the fuel electrode 21, and protons (H ⁺ ) and electrons e are generated.

Of these, the generated protons move to the oxygen electrode 16 side through the polymer electrolyte membrane 20, where O ₂ or air is supplied to the groove 15b through the connection port 17a and then toward the connection port 17b. Then, it reacts with the electrons to produce water (H ₂ O), which is discharged from the connection port 17b.

  In this way, the electrons e generated when hydrogen as a fuel comes into contact with the fuel electrode 21 move from the fuel electrode 21 to the oxygen electrode 16, and a desired electromotive force can be obtained by a load provided between the terminals.

  Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to these examples.

Example 1
First, 0.8 g of sodium borohydride (NaBH ₄ ) powder as a solid hydride and 0.2 g of oxalic acid ((COOH) ₂ ) powder as a solid acid are pulverized and mixed in a mortar. A powder was prepared, put into a screw stopper bottle, a water injection needle was inserted therein, and water was injected at a rate of 1 ml / h to generate hydrogen.

  The generated hydrogen was introduced into the fuel cell evaluation cell at 10 ml / min, and the cell voltage at 0.5 A was measured with a potentiostat.

Example 2
In this example, the procedure was the same as in Example 1 except that calcium hydride (CaH ₂ ) powder was used as the solid hydride.

Example 3
In this example, the procedure was the same as in Example 1 except that nickel hydride (NiH ₂ ) powder was used as the solid hydride.
Example 4
This example was the same as Example 1 except that lithium borohydride (LiBH ₄ ) powder was used as the solid hydride.
Example 5
This example was the same as Example 1 except that lithium aluminum hydride (LiAlH ₂ ) powder was used as the solid hydride.
Example 6
In this example, the procedure was the same as in Example 1 except that zinc chloride (ZnCl ₂ ) powder was used as the solid acid.
Comparative Example 1
In this comparative example, the same procedure as in Example 1 was performed, except that solid acid was not mixed and only a solid hydride was used to generate hydrogen at a rate of 2 ml / min or less.

The cell voltages at 0.5 A of the fuel cell evaluation cells obtained in the above examples are summarized in Table 1 below.

  Thus, in Examples 1-6 based on this invention, all show the voltage value much higher than the voltage value (0.14V) of the comparative example 1, and the high cell voltage of 0.65V or more is stabilized. You can see that it is obtained.

Example 7
FIG. 4 shows the results of calculating the correlation between the cell voltage (V) and the hydrogen flow rate (ml / min) at 0.5 A when the hydrogen supply amount is changed in the fuel cell evaluation cell of Example 1.

  According to this result, in order to stably obtain a cell voltage of 0.65 V or more at 0.5 A, it is sufficient to supply at least 10 ml / min (or even 20 ml / min or less) of hydrogen. Can understand.

  However, if the supply amount of hydrogen is less than 10 ml / min, the cell voltage tends to decrease, and the hydrogen amount is 5 ml / min or less, more preferably less than 3 ml / min, particularly 2 ml / min as in Comparative Example 1 above. If it is less than or equal to min, the cell voltage drops significantly.

  That is, in Comparative Example 1 in which only the hydride is used and the hydrogen amount is 2 ml / min or less, the hydrogen generation amount is 2 ml / min or less and the supply rate is insufficient. The cell voltage is drastically reduced to 0.14V. This means that in Examples 1 to 6, a sufficient amount of hydrogen can be generated and supplied by mixing solid acids.

Example 8
FIG. 5 shows an example in which the above-described electrochemical energy generation system 30 is actually mounted on a vehicle.

  FIG. 5A shows an automobile (vehicle) 10 having an engine unit 9 on which a plurality of unit systems 30 are connected in series to obtain a sufficient engine drive output.

  As shown in FIG. 5B, the parts of the unit system 30 in the engine unit 9 are arranged in order from the upper side to the lower side, the fuel cell 4, the water storage unit 5, the water storage chamber 2, and the storage chamber 1. . For this reason, the generated water discharged from the fuel battery cell 4 is supplied to the storage chamber 1 through the water storage unit 5 and the water storage chamber 2 by gravity regardless of power, so that a pumping pump and the like can be omitted. Each unit system 30 can be easily reduced in size, thickness, or weight.

  As mentioned above, although this invention was demonstrated based on embodiment and an Example, this invention is not limited to these examples at all, and it cannot be overemphasized that it can change suitably in the range which does not deviate from the main point of invention. .

  For example, in order to efficiently generate hydrogen, a fluidized bed method, a pressurized method, or a pulverization method is applied as a method for uniformly infiltrating water into the mixed powder 7 of hydride and acid in the storage chamber 1. be able to.

  Among them, the fluidized bed system is a system in which the mixed powder 7 of hydride and acid is made to flow with a fluidizing gas, and water is poured in this state for easy penetration. The pressurization type is a system in which the inside of the storage chamber 1 is pressurized with a pressurizing means such as a piston so that water can easily penetrate into the mixed powder 7 of hydride and acid. The pulverization method is a method in which the mixed powder 7 of hydride and acid material is crushed with a rotary blade or the like and water is easily infiltrated in this state.

  In addition, when taking out by-products (for example, metal oxides) after reaction in the unit system 30 and charging raw materials, the storage chamber 1 can be easily stored by making it into a cartridge and mounting it in the vehicle 10. The chamber 1 can also be replaced.

  The hydrogen generation method and apparatus of the present invention, and the electrochemical energy generation method and system thereof, when applied to automobiles, mobile phones, notebook personal computers, etc., realize a fuel cell with high output and excellent portability. Can do.

1 is a schematic configuration diagram of an electrochemical energy generation system according to an embodiment of the present invention. It is sectional drawing of a fuel battery cell. FIG. 2 is an exploded perspective view of the fuel battery cell. It is a graph which shows the correlation with the fuel battery cell voltage at the time of 0.5A electric power generation, and hydrogen amount. FIG. 2 is a partially transparent side view of a vehicle equipped with a fuel cell (A) and a schematic configuration diagram of a unit electrochemical energy generation system (B). It is a schematic sectional drawing of the fuel cell by a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Storage room, 2 ... Water storage room, 3 ... Water injection pipe, 4 ... Fuel cell, 5 ... Water storage part,
6 ... Hydrogen supply pipe, 7 ... Mixed powder of hydride powder and oxide powder, 8 ... Lid
9 ... Engine part, 10 ... Vehicle, 12a, 12b ... Gasket,
15a, 15b ... groove (gas flow path), 16 ... oxygen electrode, 18 ... bolt,
19a, 19b ... cell casing, 20 ... polymer electrolyte membrane, 21 ... fuel electrode,
23 ... Electrode-membrane assembly (MEA), 24 ... Hydrogen generator,
30 ... Electrochemical energy generation system

Claims (16)

A hydrogen generation method in which hydrogen is generated by supplying water to a solid mixture of a solid hydride and a solid acid.   The method for generating hydrogen according to claim 1, wherein the acid is mixed with 1 to 50% by weight of the mixed solid with respect to the hydride.   The method for generating hydrogen according to claim 1, wherein the water is supplied in an amount of 3 to 20 ml / min per 1 g of the mixed solid. As the hydride,
General formula:
MH _4-n , M (BH ₄ ) _4-n or M (AlH ₄ ) _4-n
(However, M is an alkali metal of Group 1A of the periodic table, an alkaline earth metal of Group 2A of the periodic table, a metal of Periodic Table 1B, 2B, 3A, 4A, 5A, 6A or 7A, boron Or it is aluminum and n is an integer of 0-3.)
The method for generating hydrogen according to claim 1, wherein a compound represented by the formula: The hydride, LiH, NaH, KH, MgH 2, CaH 2, TiH 2, ZrH 2, CrH 3, MoH 3, FeH 3, FeH 2, CoH, CoH 2, NiH 2, CuH, AgH, ZnH 2, BH ₃ , AlH ₃ , LiBH ₄ , NaBH ₄ , KBH ₄ , Mg (BH ₄ ) ₂ , Ca (BH ₄ ) ₂ , Ba (BH ₄ ) ₂ , Sr (BH ₄ ) ₂ , Fe (BH ₄ ) ₂ , The hydrogen generation method according to claim 4, wherein the hydrogen generation method is at least one selected from the group consisting of LiAlH ₄ , NaAlH _4, and KAlH ₄ .   The method for generating hydrogen according to claim 1, wherein an organic solid acid or an inorganic solid acid such as a sulfate, a phosphorus oxide or a chloride is used as the acidic substance. The acid substance is at least one selected from the group consisting of oxalic acid, (+)-L-ascorbic acid, citric acid, NiSO ₄ , CuSO ₄ , AlPO ₄ , ZnCl ₂ and CuCl _2. The hydrogen generation method as described.   The method for generating hydrogen according to claim 1, wherein the hydride and the acidic substance are mixed in a powder state, or the mixed powder is formed, and the water is dropped or sprayed.   The method according to any one of claims 1 to 8, further comprising: a housing part for mixed solids of solid hydride and solid acid substance; and water supply means for supplying water to the housing part. Hydrogen generator used for the implementation of   In a method for generating electrochemical energy using an electrochemical energy generation system comprising an electrochemical device using hydrogen as a raw material and a hydrogen generator, water is added to a solid mixture of solid hydride and solid acid. A method for generating electrochemical energy, characterized in that hydrogen generated by supply is led to the electrochemical device.   The method for generating electrochemical energy according to claim 10, wherein the method according to any one of claims 2 to 8 is used as the method for generating hydrogen.   The method for generating electrochemical energy according to claim 10, wherein the electrochemical device is configured as a fuel cell.   The method for generating electrochemical energy according to claim 12, wherein water generated at the oxygen electrode is refluxed to the water supply means of the hydrogen generator.   An electrochemical energy generation system comprising an electrochemical device using hydrogen as a raw material and a hydrogen generator, wherein the hydrogen generator is the hydrogen generator according to claim 9, wherein the hydrogen generated by the hydrogen generator is An electrochemical energy generation system, characterized in that hydrogen introduction means for introducing into an electrochemical device is provided.   The electrochemical energy generation system according to claim 14, wherein the electrochemical device is configured as a fuel cell.   The electrochemical energy generation system according to claim 15, wherein water generated at the oxygen electrode is returned to the water supply means of the hydrogen generator.

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