JP2014225429A - Positive electrode of magnesium air battery, magnesium air battery, and method of manufacturing positive electrode of magnesium air battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive electrode of a magnesium air battery which can increase the output current value, and to provide a method of manufacturing a positive electrode.SOLUTION: The positive electrode 260 of a magnesium air battery is constituted of a conductive member 261 formed so that a plurality of layers have a predetermined gap each other, and are interconnected electrically, and mixture activated carbon 262 adhering to the peripheral surface of the conductive member 261. The conductive member 261 is formed by bending a conductive thin plate in layer, and making a cut in each layer. The mixture activated carbon 262 is produced by mixing active carbon and latex. The conductive member 261 is composed of a porous material.

Description

  The present invention relates to a positive electrode of a magnesium air battery, air using a positive electrode active material and magnesium as a negative electrode active material, a magnesium air battery, and a method for producing a positive electrode of a magnesium air battery.

  As an example of a fuel body used in a magnesium-air battery using air as a positive electrode active material and magnesium as a negative electrode active material, Patent Document 1 discloses a cassette type fuel body. Specifically, in the fuel body described in Patent Literature 1, each end of the magnesium thin film is connected to a pair of reels, and the magnesium thin film is wound by rotating the reel, and the magnesium thin film between the reels, The positive electrode located in the vicinity cooperates to generate power.

  Patent Document 2 discloses an example of using activated carbon having a property of adsorbing oxygen as a positive electrode of a magnesium-air battery.

JP 2012-15013 A JP 2012-38666 A

  However, when activated carbon is used as the positive electrode of the magnesium-air battery, current must flow through the activated carbon, and electrons must be supplied to the hydroxide ions. In order to obtain a large current by sufficiently bringing the activated carbons into contact with each other, it is necessary to strongly compress the activated carbon in the direction of pressing the magnesium. However, as in the magnesium air battery described in Patent Document 1 and the like, in the magnesium air battery in which the magnesium film is moved and new magnesium is reacted with the positive electrode one after another, the magnesium film is moved and the magnesium film cannot be cut. It is necessary to pull with a light force. Therefore, in the magnesium-air battery described in Patent Document 1 or the like, it is difficult to increase the current by pressing activated carbon and magnesium together.

  The present invention has been made in view of such problems, and provides a positive electrode for a magnesium-air battery, a magnesium-air battery, and a method for manufacturing a positive electrode for a magnesium-air battery capable of increasing the output current value. With the goal.

In order to achieve the above object, the positive electrode of the magnesium air battery according to the first aspect of the present invention comprises
A positive electrode of a magnesium-air battery having air as a positive electrode active material and magnesium as a negative electrode active material,
A plurality of layers having a predetermined gap with each other, and a conductive member formed such that the plurality of layers are electrically connected to each other;
A carbon material in close contact with the peripheral surface of the conductive member;
It is characterized by providing.

  At least one of the plurality of layers may have one or more cuts.

  The conductive member may be made of a porous material.

The carbon material and a binding material that adheres the particles constituting the carbon material are further mixed, and further includes a mixed carbon material.
The mixed carbon material may be in close contact with the peripheral surface of the conductive member.

  The binding material may be latex.

The magnesium-air battery according to the second aspect of the present invention is
A magnesium-air battery positive electrode according to a first aspect of the present invention;
Magnesium and
An electrolyte interposed between the positive electrode of the magnesium-air battery and the magnesium;
It is characterized by providing.

Further comprising a positive electrode of another magnesium air battery,
The conductive member included in the positive electrode of the magnesium-air battery and the conductive member included in the positive electrode of another magnesium-air battery may be electrically connected to each other.

The magnesium is a plurality of film-like magnesium films,
The plurality of magnesium films are arranged at predetermined intervals on a band-shaped film,
A plurality of positive electrodes of the magnesium-air battery are arranged along the arrangement direction of the magnesium film so as to correspond to the magnesium film,
The conductive material included in the positive electrode of the magnesium-air battery so that a plurality of magnesium-air batteries composed of a plurality of positive electrodes of the magnesium-air battery and magnesium films respectively corresponding to the positive electrodes of the magnesium-air battery are connected in series. The sex member and the magnesium film may be electrically connected to each other.

  The magnesium may have a plurality of cut portions extending in the same direction.

A plurality of reaction suppression units extending in the same direction on the magnesium;
The reaction suppression unit may suppress an ionization reaction of magnesium existing in a region on the magnesium where the reaction suppression unit is disposed.

The magnesium is in the form of a film,
A plurality of carbon felts impregnated with a solution containing the electrolyte and disposed between the positive electrode of the magnesium-air battery and the magnesium along the surface of the magnesium may be further provided.

  The magnesium may be in the form of a wire.

The manufacturing method of the positive electrode of the magnesium air battery according to the third aspect of the present invention is as follows.
A method for producing a positive electrode of a magnesium-air battery using air as a positive electrode active material and magnesium as a negative electrode active material,
Forming a conductive member configured such that a plurality of layers have a predetermined gap between each other by bending the conductive thin plate one or more times;
Adhering a carbon material to the peripheral surface of the conductive member;
It is characterized by providing.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the positive electrode of a magnesium air battery, the magnesium air battery, and the positive electrode of a magnesium air battery which can increase the electric current value to output can be provided.

It is a figure showing the usage example of the magnesium air battery system which concerns on Embodiment 1. FIG. (A) is a perspective view which shows schematic structure of the fuel body for magnesium air cells which concerns on Embodiment 1, (b) is a schematic sectional drawing of the fuel body for magnesium air cells which concerns on Embodiment 1. FIG. 1 is a schematic diagram showing a schematic configuration of a magnesium air battery system according to Embodiment 1. FIG. FIG. 4 is a schematic cross-sectional view of the inside of the battery main body taken along a cutting line II shown in FIG. 3. (A) is a schematic top view of the electroconductive member before an assembly, (b) is a schematic perspective view of the electroconductive member after an assembly. FIG. 4 is a schematic cross-sectional view of the inside of a battery main body taken along a cutting line II shown in FIG. 6 is a schematic perspective view of a conductive member after assembly in Embodiment 2. FIG. It is a schematic diagram which shows schematic structure of the magnesium air battery system in Embodiment 3. It is a schematic sectional drawing inside a battery main-body part in the cutting line II-II shown in FIG. (A) And (b) is a top view which shows the modification of a magnesium film. It is a figure which shows the arrangement | positioning relationship between the carbon felt which concerns on the modification of this embodiment, and the fuel body for magnesium air cells. (A) is a photograph of a magnesium film after an experiment using a carbon felt arranged without a gap, and (b) is an experiment after an experiment using a carbon felt arranged with a gap. It is a photograph of a magnesium film. (A) is a schematic block diagram of the magnesium air battery system which concerns on the modification of this embodiment, (b) is a schematic sectional drawing of the magnesium air battery unit in the cutting line III-III of (a).

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram illustrating a usage example of the magnesium-air battery system 200 according to the first embodiment, and is a diagram illustrating an example in which the magnesium-air battery fuel body 100 is used in the magnesium-air battery system 200 included in the electric device 300. is there.

  The magnesium-air battery fuel element 100 according to this embodiment is used as a fuel for a magnesium-air battery using air as a positive electrode active material and magnesium as a negative electrode active material.

  In addition, the magnesium-air battery system 200 according to the present embodiment is a system that includes a magnesium-air battery that generates electricity using the magnesium-air battery fuel element 100 as a negative electrode, and supplies the generated power to the electric device 300.

  The electric device 300 is a device that is driven using power supplied from the magnesium-air battery system 200 as a power source, and is, for example, a mobile phone or a personal computer. A magnesium-air battery system 200 is housed in the housing 310 of the electric device 300. The casing 310 of the electric device 300 includes an insertion port 320 for supplying the magnesium-air battery fuel element 100 to the magnesium-air battery system 200, and a magnesium-air battery fuel element 100 after use (hereinafter referred to as “used”). And an outlet 330 for taking out the fuel body).

  Next, the magnesium-air battery fuel element 100 according to this embodiment will be described in detail.

  FIG. 2A is a perspective view showing a schematic configuration of the magnesium-air battery fuel element 100 according to this embodiment, and FIG. 2B is a cross-sectional view of the magnesium-air battery fuel element 100. As shown in FIGS. 2A and 2B, the magnesium-air battery fuel element 100 is wound around a hollow cylindrical reel 410 and has a conductive film 110 and a magnesium film 120 attached on the conductive film 110. And a transparent film 130 covering the magnesium film 120, and is formed into a roll shape.

  The magnesium-air battery fuel element 100 is formed, for example, by forming a magnesium film 120 on the conductive film 110 by vapor deposition or the like, and then allowing the surface of the magnesium film 120 to transmit ions that react with magnesium such as oxygen and hydroxyl groups. It is formed by covering with a film 130. Then, the magnesium-air battery fuel element 100 is wound around a reel 410 in a roll shape as shown in FIG.

  Next, the magnesium air battery system 200 according to the present embodiment will be described in detail.

  FIG. 3 is a schematic diagram showing a schematic configuration of the magnesium-air battery system 200 according to the first embodiment. As shown in FIG. 3, the magnesium-air battery system 200 includes a supply unit 210, a battery main body unit 220, a winding unit 230, and a drive unit 240.

  The supply unit 210 is connected to the magnesium-air battery fuel element 100 and is rotatable about the roll axis of the connected magnesium-air battery element 100. The magnesium-air battery fuel element 100 is connected to the magnesium-air battery fuel element 100 via the battery body 220. To the winding unit 230.

  Specifically, as shown in FIG. 3, the supply unit 210 includes a shaft that is driven to rotate clockwise by the drive unit 240. The shaft of the supply unit 210 is configured to be detachable from the reel 410 around which the magnesium-air battery fuel 100 is wound. The shaft of the supply unit 210 passes through the center hole of the reel 410 around which the magnesium-air battery fuel element 100 is wound, and the supply unit 210 and the magnesium-air battery fuel element 100 are connected. As a result, the magnesium-air battery fuel element 100 rotates around the roll axis together with the supply part 210 and is sent out to the battery body part 220.

  The battery main body 220 includes a positive electrode and an electrolyte, and functions as a magnesium-air battery that generates power in cooperation with the positive electrode, using the magnesium-air battery fuel body 100 delivered from the supply unit 210 as a negative electrode. . Specifically, the battery body 220 sandwiches and supports the magnesium-air battery fuel body 100 and sends the magnesium-air battery fuel body 100 after the power generation reaction (after use) to the winding unit 230. The battery body 220 has an electrolyte inlet 221.

  The electrolyte of the battery main body 220 is, for example, sodium chloride. The electrolyte is supplied into the battery main body 220 from the inlet 221 of the battery main body 220.

  FIG. 4 is a schematic cross-sectional view of the inside of the battery main body 220 taken along the cutting line II shown in FIG. As shown in FIG. 4, the battery main body 220 according to the present embodiment accommodates the positive electrode 260 and the carbon felt 270 therein. The positive electrode 260 includes a conductive member 261, a mixed activated carbon 262, and a case 263 in which the conductive member 261 and the mixed activated carbon 262 are accommodated.

  The conductive member 261 has a function of carrying electrons to the mixed activated carbon 262. FIG. 5A shows a schematic plan view of the conductive member 261 before assembly, and FIG. 5B shows a schematic perspective view of the conductive member 261 after assembly. As shown in FIG. 5A, the conductive member 261 is formed from a single sheet of a substantially rectangular conductive thin plate. The material of the conductive thin plate is, for example, copper or titanium. As shown in FIG. 5B, the conductive member 261 is configured such that two layers have a predetermined gap and are electrically connected to each other. More specifically, the conductive member 261 is formed of a single conductive thin plate integrally from a base portion 261a, a plurality of strip portions 261b, and a terminal portion 261c. One end portion of the plurality of strip portions 261b is configured to bend in a direction perpendicular to the surface from which the base portion 261a is located, and the other end portion is integrally coupled to the base portion 261a. The terminal portion 261c is provided so as to protrude from the base portion 261a, and functions as a positive electrode terminal.

  Next, a method for manufacturing the conductive member 261 will be described.

  First, as shown in FIG. 5A, a plurality of cuts are made so that a plurality of strip portions 261b are formed in a part of the conductive thin plate. Thereafter, the conductive plate is folded in substantially half with the same direction as the cut direction as the folding line. Further, as shown in FIG. 5B, the conductive member 261 is created by randomly bending the end portions of the plurality of strip portions 261b in the vertical direction (direction perpendicular to the base portion 261a). In the example shown in FIGS. 5A and 5B, the slits 261b are formed so as to form seven strips 261b, but the number of strips 261b and the number of cuts are not limited thereto. . Further, the number of times the conductive thin plate is bent is not limited to one.

  Thus, since the conductive member 261 is formed so as to have a plurality of strip portions 261b, the contact area between the conductive member 261 and the mixed activated carbon 262 can be increased. The current value can be increased.

  Returning to FIG. 4, the mixed activated carbon 262 is a mixture of activated carbon and latex. The activated carbon contained in the mixed activated carbon 262 is used as a positive electrode of a magnesium-air battery in order to perform an oxygen redox reaction using oxygen in the air as a positive electrode active material. As shown in FIG. 4, the mixed activated carbon 262 is disposed so as to be in close contact with the conductive member 261 formed in two folds or on the upper and lower surfaces of the conductive member 261.

  Next, the manufacturing method of the mixed activated carbon 262 is demonstrated.

  First, water and carbon powder are mixed in a weight ratio of water: carbon powder = 50: 50 and stirred to produce a mixed solution A. Then, the mixed solution A and the latex are mixed at a weight ratio of a mixed solution A: latex = 3: 1 and stirred to produce a mixed solution B. Moreover, the mixed activated carbon 262 is produced | generated by mixing the liquid mixture B and activated carbon in the ratio of the liquid mixture B: activated carbon = 12: 6.

  When the mixed activated carbon 262 generated as described above is dried to remove moisture, the mixed activated carbon 262 contracts due to the elastic action of the latex, and the activated carbon particles contained in the mixed activated carbon 262 are strongly adhered to each other. Thereby, since the contact area of the activated carbon particles contained in the mixed activated carbon 262 can be increased, the current value that can be output from the magnesium-air battery can be increased. Further, the latex itself does not have conductivity, but can be made conductive by mixing with water in which carbon powder is dissolved.

  Note that since the latex itself is an insulator, the mixed activated carbon 262 is also insulated when the amount of latex is large. On the other hand, when the amount of latex is small, the force for bringing the activated carbon particles into close contact with each other also becomes small. Therefore, it is preferable to generate the mixed activated carbon 262 at the above-described weight ratio as a weight ratio that can sufficiently ensure both the conductivity of the mixed activated carbon 262 and the adhesion between the activated carbon particles. In addition, the weight ratio mentioned above is an example, A preferable weight ratio is suitably determined according to the kind of carbon, the particle size of activated carbon, etc. In the present embodiment, activated carbon is used as a carbon material that adsorbs oxygen, which is a positive electrode active material, but is not limited thereto. For example, carbon nanotubes may be used as the carbon material of the positive electrode 260. Moreover, in this embodiment, latex is used as an example of a binding substance for bringing the activated carbon particles into close contact with each other. However, a material that can be used as the binding substance is not limited to latex.

  The carbon felt 270 is a felt containing carbon powder and fibers such as activated carbon, and is disposed between the magnesium-air battery fuel body 100 and the positive electrode 260. The carbon felt 270 is impregnated with an electrolytic solution in which an electrolyte is dissolved. The carbon felt 270 can hold a sufficient amount of oxygen with the electrolyte as compared to a felt that does not contain carbon.

  Returning to FIG. 3, the winding unit 230 winds up the magnesium-air battery fuel body 100 after the power generation reaction in the battery main body unit 220 to form a roll-shaped spent fuel body 500 that can be removed from the winding unit 230. To do.

  Specifically, like the supply unit 210, the winding unit 230 includes a shaft that is rotationally driven clockwise by the drive unit 240, as shown in FIG. The shaft of the winding unit 230 is configured to be detachable from the reel 420 around which the spent fuel 500 is wound. The shaft of the winding unit 230 passes through the center hole of the reel 420 around which the spent fuel body 500 is wound, and the winding unit 230 and the spent fuel body 500 are connected. As a result, the magnesium-air battery fuel element 100 after the power generation reaction is rotated and wound around the roll axis together with the winding part 230, and a roll-shaped spent fuel element 500 is formed.

  The drive unit 240 rotationally drives the supply unit 210 and the winding unit 230. The drive unit 240 is realized by, for example, a spring or an electric motor. When the electrical device 300 is a device that requires relatively small electrical energy, such as a mobile phone or a personal computer, a spring is used as the drive unit 240, and the spring is manually wound, thereby supplying the supply unit 210 and The winding unit 230 is preferably rotationally driven. Alternatively, as the drive unit 240, a knob and a mechanism for transmitting the rotational torque of the knob to the supply unit 210 and the winding unit 230 are provided, and by manually rotating the knob, the supply unit 210 and the winding unit 230 May be driven to rotate.

  Moreover, in the electric equipment 300 using the magnesium air battery, a standby state where power is not actually used and a use state where power is used are repeated. In such a case, when only the spring is used as the drive unit 240 and the supply unit 210 and the winding unit 230 are rotationally driven, the magnesium-air battery fuel assembly 100 can be used even when the electric device 300 is not used. Winding is performed. As an example of a method for preventing this, the rotation speed of the shafts of the supply unit 210 and the winding unit 230 is changed by a well-known continuously variable transmission mechanism according to the current used by the electric device 300 or the current that can be generated by the magnesium air battery. You may let them. In addition, for example, the supply unit 210 and the winding unit are configured so that the magnesium-air battery fuel body 100 moves a predetermined distance every predetermined time by opening and closing a switch for switching between winding and stopping of the magnesium-air battery fuel body 100. The rotational driving of 230 may be controlled. Furthermore, by using a small button battery together, a control signal for starting winding of the magnesium-air battery fuel element 100 can be transmitted to the drive unit 240 from a state where the magnesium-air battery is completely stopped. it can.

  According to the magnesium-air battery system 200 configured as described above, the contact area between the conductive member 261 of the positive electrode 260 and the mixed activated carbon 262 can be increased, so that the output current value of the magnesium-air battery is increased. be able to.

  Further, the activated carbon is mixed with latex and is brought into close contact with the conductive member 261 as the mixed activated carbon 262. Therefore, the activated carbon particles are strongly adhered to each other by the elastic action of the latex, and the contact area between the activated carbon particles can be increased, so that the current value that can be output from the magnesium-air battery can be increased.

(Embodiment 2)
Next, Embodiment 2 will be described. In the first embodiment, as illustrated in FIG. 4, the example in which one positive electrode 260 and the magnesium-air battery fuel element 100 function as a magnesium-air battery has been described. However, the positive electrode 260 and the magnesium-air battery fuel element are described. The arrangement of 100 is not limited to the arrangement shown in FIG. In the present embodiment, as another example, an example in which the two positive electrodes 260 and the magnesium-air battery fuel element 100 function as a magnesium-air battery will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  6 is a schematic cross-sectional view of the inside of the battery main body 220 taken along the cutting line II shown in FIG. 3 in the present embodiment. As shown in FIG. 6, in the battery main body 220 according to the present embodiment, two positive electrodes 260 are arranged to face each other so as to sandwich the magnesium-air battery fuel element 100. In this manner, the magnesium-air battery fuel body 100 is sandwiched between the two positive electrodes 260, so that the magnesium-air battery fuel body 100 is compared with the magnesium-air battery composed of one positive electrode 260 and the magnesium-air battery fuel body 100. , Larger output can be obtained.

  Further, the conductive members 261 included in the two positive electrodes 260 are configured to be electrically connected to each other. FIG. 7 is a schematic perspective view of the conductive member 261 after assembly according to the present embodiment. As in the first embodiment, the conductive member 261 according to the present embodiment includes a plurality of substantially rectangular conductive thin plates such that a plurality of strip portions 261b are formed in a part of the conductive thin plate. Then, as shown in FIG. 7, it is bent so that the cross section is substantially M-shaped, with the same direction as the cutting direction being the folding line. Further, the conductive member 261 is created by bending the end portions of the plurality of strip portions 261b randomly in the vertical direction (direction perpendicular to the base portion 261a).

  In the conductive member 261 created as described above, as shown in FIGS. 6 and 7, the conductive portions 261d and 261e included in the two positive electrodes 260 are electrically connected to the conductive portions 261d and 261e, respectively. And the connecting portion 261f to be integrated. The conductive portions 261d and 261e function in the same manner as the conductive member 261 according to the first embodiment, and the current flowing through the conductive portions 261d and 261e and the connection portion 261f can be obtained from one terminal portion 261c.

(Embodiment 3)
Next, Embodiment 3 will be described. In the third embodiment, another example of the magnesium air battery system 200 according to the first embodiment will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 8 is a schematic diagram showing a schematic configuration of the magnesium-air battery system 200a according to the third embodiment. As shown in FIG. 8, the magnesium-air battery system 200a includes a battery body group 280 including three battery body parts 220a, 220b, and 220c, a supply part 210 similar to that in the first embodiment, a winding part 230, and And a drive unit 240.

  FIG. 9 shows a schematic cross-sectional view of the main parts of the battery body group 280 and the magnesium-air battery fuel element 100 taken along the section line II-II in FIG. As shown in FIG. 9, the same positive electrodes 260 a, 260 b, and 260 c as those in the first embodiment are accommodated in the three battery main body portions 220 a, 220 b, and 220 c that constitute the battery main body group 280. Further, in the magnesium-air battery fuel element 100 according to the present embodiment, the magnesium film 120 is disposed on the strip-shaped conductive film 110 at a predetermined interval in the winding direction (the direction of arrow A in FIG. 9). . The interval between the magnesium films 120 corresponds to the interval between the positive electrodes 260a, 260b, and 260c.

  In addition, the conductive member 261 of the positive electrode 260a is electrically connected to the magnesium film 120 serving as the negative electrode of the positive electrode 260b. In addition, the conductive member 261 of the positive electrode 260b is electrically connected to the magnesium film 120 serving as the negative electrode of the positive electrode 260c. Further, the magnesium film 120 serving as the negative electrode of the positive electrode 260a is connected to the negative electrode terminal, and the conductive member 261 of the positive electrode 260c is connected to the positive electrode terminal. That is, the positive electrodes 260a, 260b, 260c, and the magnesium film 120 are connected in series so that a plurality of magnesium air batteries composed of the positive electrodes 260a, 260b, 260c and the magnesium film 120 serving as these negative electrodes are connected in series. They are electrically connected to each other.

  Therefore, in the magnesium-air battery system 200a according to the present embodiment, the drive unit 240 is rotationally driven at a predetermined timing, and in the direction of arrow A shown in FIG. The voltage output when three magnesium air batteries are connected in series can be obtained.

  In the above embodiment, the battery main body group 280 has been described as an example including three battery main body portions 220. However, the number of battery main body portions 220 constituting the battery main body group 280 is not limited to this, The battery main body group 280 can be configured by an arbitrary number of battery main body portions 220.

  As mentioned above, although embodiment of this invention was described, this invention is not limited by said embodiment.

  For example, in the above-described embodiment, the magnesium-air battery fuel element 100 has been described as being formed in a roll shape from the magnesium film 120. However, the shape of magnesium used as the negative electrode may not be a film, The shape is not limited as long as it can be wound. For example, a magnesium wire may be used as the negative electrode. Magnesium wires are easier to manufacture than magnesium films and can reduce manufacturing costs. Further, since the magnesium wire has a large surface area even with the same weight as the magnesium film, the reaction rate with oxygen is high, and a larger current output can be obtained. Further, the magnesium wire has an advantage that it is less likely to break against the tension than the magnesium film.

  Moreover, as shown to Fig.10 (a), the magnesium film 120 may have the some notch part 121 extended in the same direction mutually. Thereby, since the surface area of the magnesium film 120 can be enlarged, the electric current value which can be output of a magnesium air battery can be increased. Moreover, when the cut | notch is formed in the random direction in the magnesium film 120, although the surface area of a magnesium film increases, an extra circuit is formed between the part which reacts in the magnesium film 120, and the part which does not react. Current can be wasted. However, as shown in FIG. 10A, by forming the notch 121 in the same direction, the flow of electricity is limited to the direction of the notch, and current can be efficiently extracted. Moreover, since the part in which the notch part 121 of the magnesium film 120 is not formed is integrated and electrically connected, an electric current can be easily taken out from the magnesium film 120. Instead of forming the cut portion 121, an obstacle may be arranged so that the magnesium film 120 in the region where the obstacle is arranged does not ionize. Moreover, as shown in FIG.10 (b), you may arrange | position several linear magnesium 122 in the same direction. Thereby, the magnesium film 120 in the region where the magnesium 122 is arranged remains without being ionized, and the magnesium 122 and the magnesium film 120 in the region where the magnesium 122 are arranged jointly secure a passage through which current flows. Therefore, even when the parts of the magnesium film 120 are divided as the reaction progresses, the current can be effectively extracted.

  In the above-described embodiment, the example in which the conductive member 261 constituting the positive electrode 260 has a plurality of strip portions 261b has been described. However, the contact area between the conductive member 261 and the mixed activated carbon 262 is increased. If it is done, the shape does not matter. For example, the conductive member 261 may be made of a porous material.

  In the above-described embodiment, the example in which the plurality of strip portions 261b are configured to be integrated in the base portion 261a has been described, but the shape of the conductive member 261 is not limited thereto. For example, the conductive member 261 may be formed by electrically connecting a plurality of strip-shaped members made of a conductive thin plate to each other by a conducting wire or the like. In this case, the plurality of strip-shaped members function in the same manner as the plurality of strip portions 261b in the above embodiment, and the contact area between the conductive member 261 and the mixed activated carbon 262 can be increased.

  In the above embodiment, as an example of the method for manufacturing the positive electrode 260, the conductive thin plate is bent to form the conductive member 261, and then the mixed activated carbon 262 is adhered to the peripheral surface of the conductive member 261. The manufacturing method of the positive electrode 260 is not limited to this. For example, you may manufacture the electroconductive member 261 to which the mixed activated carbon 262 contact | adhered by making it bend after apply | coating the mixed activated carbon 262 to a conductive thin plate.

  In the above embodiment, the carbon felt 270 is disposed so as to be interposed between the magnesium-air battery fuel element 100 and the positive electrode 260 as shown in FIG. The arrangement mode is not limited to this. FIG. 11 shows an example of another arrangement mode of the carbon felt 270. FIG. 11 is a diagram showing an arrangement relationship between the carbon felt 270 and the magnesium-air battery fuel element 100 according to a modification of the present embodiment. In FIG. 11, strip-shaped carbon felts 270 are in contact with the magnesium-air battery fuel element 100 in a state of being arranged with a gap therebetween. By arranging the carbon felt 270 with a gap in this way, hydrogen that is a side reaction product and nitrogen that has not reacted in the air are prevented from accumulating in the battery even when the battery size increases. It can suppress that the efficiency of a battery reaction falls. Moreover, in the area | region which is not in contact with the carbon felt 270, ie, the area | region of the clearance gap between the carbon felts 270, magnesium remains without reacting. Therefore, even after magnesium in another region is used for the battery reaction, a current path is secured, so that a current output can be obtained for a long time.

  12A and 12B show photographs of the magnesium film 120 used in the battery reaction experiment. The magnesium film 120 in FIG. 12 (a) is a result of an experiment conducted in contact with the carbon felt 270 in which no gap is provided. In the experiment of FIG. 12A, since the battery reaction occurs randomly on the area where the magnesium film 120 and the carbon felt 270 are in contact with each other, the voltage is rapidly lowered and the wire is disconnected. On the other hand, the magnesium film 120 in FIG. 12B is a result of an experiment conducted in contact with the carbon felt 270 provided with a gap. In the experiment of FIG. 12B, a current of 5 A continuously flowed for 30 minutes or more and functioned as a stable battery. That is, as shown in FIG. 11, by arranging the carbon felt 270 with a gap, a magnesium region that does not cause a battery reaction corresponding to the gap is formed, so that the battery reaction occurs uniformly. And a stable battery can be obtained.

  Further, in the above-described embodiment, the magnesium-air battery fuel element 100 serving as the negative electrode is composed of the magnesium film 120 formed from pure magnesium, but the film constituting the negative electrode is not limited to pure magnesium. . Here, in the magnesium air battery disclosed in Patent Document 2, magnesium oxide produced in the negative electrode made of magnesium is dissolved in an aqueous solution of citrate, and a reaction occurs between the newly appeared magnesium surface and the positive electrode. . However, since the reaction rate of dissolving magnesium oxide with an aqueous solution of citrate is considerably slower than the ionization rate of magnesium, the reaction rate of the entire magnesium battery also depends on the reaction rate of dissolving magnesium oxide with an aqueous solution of citrate. Will be late. As another example of the magnesium-air battery, an alloy of magnesium and calcium is used as a negative electrode. In this case, the reaction rate between calcium and magnesium hydroxide is rate-limiting. In contrast to these magnesium-air batteries, the magnesium-air battery according to this embodiment uses the magnesium film 120 formed of pure magnesium as the negative electrode, so that the ionization rate of magnesium becomes the reaction rate of the entire magnesium-air battery, and is larger. A current output can be obtained. Therefore, in the present invention, the negative electrode is preferably pure magnesium.

  In the magnesium-air battery system 200 according to the above embodiment, the magnesium film 120 serving as the negative electrode is sent out from the supply unit 210 to the positive electrode 260 in the battery main body 220 as the magnesium-air battery fuel element 100, and after the reaction, The used fuel body 500 is wound around the winding unit 230. However, the configuration of the magnesium-air battery system 200 is not limited to the configuration in which the magnesium film 120 is appropriately sent to the positive electrode 260 as described above. Hereinafter, another configuration example of the magnesium air battery system 200 will be described.

  FIG. 13A is a schematic configuration diagram of a magnesium air battery system 200b according to a modification of the present embodiment, and FIG. 13B is a schematic cross-sectional view of the magnesium air battery unit taken along the section line III-III in FIG. . As shown in FIG. 13A, the magnesium-air battery system 200b includes three magnesium-air battery units 290. The number of magnesium air battery units 290 constituting the magnesium air battery system 200b is not limited to this, and the magnesium air battery system 200b can be constituted by an arbitrary number of magnesium air battery units 290. 13B, the magnesium-air battery unit 290 includes a magnesium film 120, a positive electrode 260 that sandwiches the magnesium film 120, and a case 291 that houses the magnesium film 120 and the positive electrode 260. The Further, the magnesium film 120 and the positive electrode 260 are configured to form layers in the horizontal direction.

  In the magnesium-air battery system 200b configured as described above, when the electrolyte 292 such as salt water is injected into the magnesium-air battery unit 290, the electrolyte 292 collects in the lower part of the case 291. And as shown in FIG.13 (b), oxidation-reduction reaction advances only in the part of the magnesium film 120 and the positive electrode 260 (area | region C of FIG.13 (b)) immersed in the electrolyte solution 292. FIG. Therefore, by gradually injecting the electrolytic solution 292 into the magnesium air battery unit 290, the same effect as the magnesium air battery system 200 according to the above embodiment in which the magnesium film 120 is appropriately sent to the positive electrode 260 can be obtained.

Next, the volume required in the magnesium air battery system 200 in the above embodiment and the magnesium air battery system 200b according to this modification will be compared. Hereinafter, in both of the magnesium-air battery systems 200 and 200b, the surface area where the positive electrode 260 and the magnesium film 120 are in contact is S, the thickness of the positive electrode 260 is D, and the thickness of the magnesium film is d. In this case, the total volume of magnesium that can be used in the magnesium air battery system 200b including the N magnesium air battery units 290 is SdN. The volume occupied by the entire magnesium air battery system 200b is SDN. Accordingly, the ratio of magnesium to the entire magnesium air battery system 200b is d / D. Specifically, when d = 40 μm and D = 1 cm, d / D = 0.004. That is, it is assumed that the magnesium-air battery system 200b has a volume 250 times that of magnesium that can be used. More specifically, in order to use 3.6 kg of magnesium having a density of 1.74 g / cm ³ in a magnesium air battery unit 290 having S = 20 cm × 20 cm = 400 cm ² and D = 1 cm, about 1300 pieces are used. When the magnesium air battery units 290 are arranged along the depth direction of the sheet of FIG. 13A, the length of the magnesium air battery unit 290 reaches 13 m.

On the other hand, in the take-up type magnesium air battery system 200, the total volume necessary for using the same volume of magnesium as the magnesium air battery system 200b is the positive electrode 260 in which the oxidation-reduction reaction is performed, and the rolled magnesium film 120. And the volume. Specifically, if the radius of the roll-shaped magnesium film 120 is R and the width is L, the volume is πR ² L, so 3.6 kg of magnesium having a density of 1.74 g / cm ³ is L = 50 cm. When formed in a roll shape, the radius R is about 3.6 cm. Since the volume of the roll-shaped magnesium film 120 and the volume of the positive electrode 260 in which the oxidation-reduction reaction is performed is the take-up type magnesium air battery system 200, it is significantly larger than the magnesium air battery system 200b described above. It can be seen that downsizing is possible. Therefore, in the present invention, the take-up type magnesium air battery system 200 is preferable.

DESCRIPTION OF SYMBOLS 100 Magnesium-air battery fuel body 110 Conductive film 120 Magnesium film 120a Magnesium film body 121 Cut part 122 Magnesium 130 Transmission film 200, 200a, 200b Magnesium air battery system 210 Supply part 220, 220a-220c Battery body part 221 Inlet 230 Winding part 240 Drive part 260, 260a-260c Positive electrode 261 Conductive member 261a Base part 261b Strip part 261c Terminal part 261d, 261e Conductive part 261f Connection part 262 Mixed activated carbon 263 Case 270 Carbon felt 280 Battery body group 290 Magnesium air battery unit 291 Case 292 Electrolyte 300 Electric appliance 310 Housing 320 Insertion port 330 Outlet 410, 420 Reel 500 Spent fuel element

Claims (13)

A positive electrode of a magnesium-air battery having air as a positive electrode active material and magnesium as a negative electrode active material,
A plurality of layers having a predetermined gap with each other, and a conductive member formed such that the plurality of layers are electrically connected to each other;
A carbon material in close contact with the peripheral surface of the conductive member;
A magnesium-air battery positive electrode comprising: At least one of the plurality of layers has one or more cuts;
The positive electrode of the magnesium air battery according to claim 1. The conductive member is made of a porous material,
The positive electrode of the magnesium air battery according to claim 1 or 2, The carbon material and a binding material that adheres the particles constituting the carbon material are further mixed, and further includes a mixed carbon material.
The mixed carbon material is in close contact with the peripheral surface of the conductive member;
The positive electrode of the magnesium air battery according to any one of claims 1 to 3, The binding material is latex;
The positive electrode of the magnesium-air battery according to claim 4. The positive electrode of the magnesium air battery according to any one of claims 1 to 5,
Magnesium and
An electrolyte interposed between the positive electrode of the magnesium-air battery and the magnesium;
A magnesium-air battery comprising: Further comprising a positive electrode of another magnesium air battery,
The conductive member included in the positive electrode of the magnesium-air battery and the conductive member included in the positive electrode of the other magnesium-air battery are electrically connected to each other.
The magnesium-air battery according to claim 6. The magnesium is a plurality of film-like magnesium films,
The plurality of magnesium films are arranged at predetermined intervals on a band-shaped film,
A plurality of positive electrodes of the magnesium-air battery are arranged along the arrangement direction of the magnesium film so as to correspond to the magnesium film,
The conductive material included in the positive electrode of the magnesium-air battery so that a plurality of magnesium-air batteries composed of a plurality of positive electrodes of the magnesium-air battery and magnesium films respectively corresponding to the positive electrodes of the magnesium-air battery are connected in series. The conductive member and the magnesium film are electrically connected to each other,
The magnesium-air battery according to claim 6 or 7, wherein: The magnesium has a plurality of cut portions extending in the same direction.
The magnesium-air battery according to any one of claims 6 to 8, wherein A plurality of reaction suppression units extending in the same direction on the magnesium;
The reaction suppression unit suppresses an ionization reaction of magnesium present in a region on the magnesium where the reaction suppression unit is disposed.
The magnesium-air battery according to any one of claims 6 to 8, wherein The magnesium is in the form of a film,
Impregnating a solution containing the electrolyte, and further comprising a plurality of carbon felts disposed between the positive electrode of the magnesium-air battery and the magnesium along the surface of the magnesium so as to be spaced apart from each other.
The magnesium-air battery according to any one of claims 6 to 10, wherein: The magnesium is wire-shaped,
The magnesium-air battery according to claim 6 or 7, wherein: A method for producing a positive electrode of a magnesium-air battery using air as a positive electrode active material and magnesium as a negative electrode active material,
Forming a conductive member configured such that a plurality of layers have a predetermined gap between each other by bending the conductive thin plate one or more times;
Adhering a carbon material to the peripheral surface of the conductive member;
The manufacturing method of the positive electrode of a magnesium air battery characterized by the above-mentioned.