JP2019204677A - Air cell and method of manufacturing air cell - Google Patents

Abstract

To provide an air cell capable of preventing the breakage of an outer container due to an expansion of a negative electrode.SOLUTION: An air cell 1001 accommodates, between main walls 501, 506 of an outer container, a metal negative electrode 300 and a positive electrode 100 for discharge which is an air electrode. The thickness of an active material in each of active material layers 302, 303 is thinnest in a portion closest to one end of a negative electrode collector 301, a negative electrode lead terminal 311 being attached to the one end, and increases towards the other end in a portion except the portion closest to the one end.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to an air battery covered with a container having a multilayer structure and a manufacturing method thereof, and more particularly, to an improvement for protecting the outer container from expansion of a negative electrode due to deposition of an active material.

  As an exterior container formed of a multilayer structure, there is one disclosed in Patent Document 1. This exterior container consists of the positive electrode side laminate sheet which accommodates the positive electrode of an air battery, and the negative electrode side laminate sheet which accommodates the negative electrode of an air battery. The laminate sheet on the positive electrode side and the negative electrode side is a multilayer structure, and one of the layers includes a film having water repellency.

  Patent Document 2 discloses an air battery in which a slit is formed at a free end of a negative electrode.

  A reaction product generated by a chemical reaction between the positive electrode and the negative electrode passes through this slit and moves toward a surface of the negative electrode that does not face the positive electrode. Since the reaction product by the chemical reaction is dispersed, in the air battery of Patent Document 2, deposition of the reaction product does not concentrate between the negative electrode and the positive electrode. Due to such dispersion, the stress due to the deposition of the reaction product is prevented from acting on the air electrode as the positive electrode or the outer container.

JP 2004-288572 A JP 2017-4644 A

  By the way, the active material particles constituting the active material layer of the negative electrode repeat a chemical reaction in the process of charge and discharge. Such a chemical reaction of the active material particles does not occur uniformly throughout the negative electrode, but has a positional bias that it frequently occurs near the lead terminal where the contribution of electron conduction resistance is small. Such positional deviation of the chemical reaction causes a partial expansion of the negative electrode. The outer packaging container of an air battery described in Patent Document 1 has a structure in which a laminate sheet and a water repellent layer are joined, and the joined portion does not have sufficient strength. Therefore, there is a problem that the negative electrode expands and breaks when part of it receives stress. Since the electrolytic solution is accommodated in the exterior container, the electrolytic solution leaks from the broken portion even if the fracture due to stress is very small.

  As described in Patent Document 2, it is conceivable to provide a slit in the negative electrode to promote the circulation of the reaction product and to disperse the deposits of the reaction product. However, as described above, when the generation of a chemical reaction is concentrated at a part of the negative electrode, a large amount of reaction products are generated at that position, which may cause clogging of the slit. When the reaction product circulates due to clogging of the slit, the reaction product deposition between the negative electrode and the positive electrode does not stop, and the stress caused by the expanded negative electrode acts on the outer container, There is a problem that breakage of the outer container and liquid leakage cannot be prevented.

  The objective of this invention is providing the air battery which can avoid the concentration of the generation | occurrence | production location of the chemical reaction at the time of charging / discharging.

  In the air battery capable of solving the above problems, an electrolytic solution, a positive electrode that is an air electrode, and a negative electrode are accommodated in an outer container of a multilayer structure including a layer having a vent and a layer having water repellency. The negative electrode includes a current collector, a lead terminal attached to one end of the current collector, and an active material layer formed on the remaining portion of the current collector. The material layer includes a portion of the current collector that increases in thickness in a direction away from the mounting position side of the lead terminal.

An air battery manufacturing method capable of solving the above problems includes a formation step of attaching a lead terminal to one end of a current collector and forming an active material layer on the remaining portion, a layer having a vent, and a repellent A housing step of housing the negative electrode and the positive electrode in an outer packaging container of a multilayer structure including an aqueous layer, and an injection step of injecting an electrolyte into the outer packaging container,
In forming the active material layer in the forming step, a portion where the thickness of the active material layer increases in a direction away from the lead terminal mounting position side is formed.

  In the present disclosure, since the thickness of the pre-active material layer increases in a direction away from the mounting position side of the lead terminal in the current collector, the ion conduction resistance due to the electrolytic solution between the negative electrode and the positive electrode Is the maximum at the portion closest to the portion where the lead terminal is attached. On the other hand, the path length of the current flowing from the lead terminal is minimized in the vicinity of the lead terminal and becomes longer as the distance from the lead terminal increases. In the battery, the current flowing from the negative electrode to each part of the positive electrode is determined by the contribution of both the electron conduction resistance based on the current path length from the lead terminal and the ionic conduction resistance of the electrolyte. Considering the fact that while the path length is short and the electron conduction resistance is small, the ion conduction resistance is high, while the current path length is long and the electron conduction resistance is large at a distance from the lead terminal, the lead conduction resistance is small. It is possible to achieve a balance between the current value flowing from the nearest terminal to the positive electrode and the current value flowing from the location far from the lead terminal to the positive electrode. As a result, the amount of reaction product produced is also balanced between the electrolyte near the lead terminal and the electrolyte far from the lead terminal. Therefore, the reaction product is generated at a uniform frequency throughout the negative electrode. Therefore, even when the negative electrode expands due to the deposition of the active material, the entire negative electrode can be expanded at a substantially uniform ratio. Since the stress due to the negative electrode expansion is dispersed throughout the negative electrode, it is possible to avoid the outer container from breaking due to the stress being concentrated on a part of the outer container and preventing leakage of the electrolyte. be able to.

  Further, in the present disclosure, instead of causing the reaction product to flow and disperse, the flowability of the current that is the basis of the charge / discharge reaction is made uniform throughout the negative electrode, so that the reaction product is clogged. The protection of the outer container can be continued.

1 is a perspective view illustrating an air battery 1001 according to Embodiment 1 of the present disclosure. It is an exploded view which shows the air battery 1001 disassembled into components. 1 is a cross-sectional view of an air battery 1001. FIG. FIG. 6 is a diagram showing an extracted negative electrode current collector 301, an active material layer 303, and a positive electrode current collector 106 for discharge. FIG. 6 is a process diagram showing a manufacturing process of the air battery 1001. FIGS. 6A to 6E are diagrams illustrating steps in which the air battery 1001 according to the first embodiment is manufactured. FIGS. 7A to 7F are diagrams illustrating a process of forming the separator case 400 according to the first embodiment and injecting the active material particles 302m and the binder 302b into the case. FIG. 8A is a perspective view of a bipolar air battery 1002 according to the second embodiment. FIG. 8B is a cross-sectional view of the bipolar air battery 1002 according to the second embodiment. FIG. 9A is a perspective view of a three-pole air battery 1003 according to the third embodiment. FIG. 9B is a cross-sectional view of the tripolar air battery 1003 according to the third embodiment. FIG. 10A is a cross-sectional view of a metal negative electrode in which an active material layer 342 is formed on the first negative electrode surface 312 and an active material layer 343 is formed on the second negative electrode surface 313. FIGS. 10B and 10C are cross-sectional views taken along the line AA ′ and the line BB ′.

    Hereinafter, a metal-air battery and a method for manufacturing the metal-air battery according to an embodiment of the present disclosure will be described with reference to the drawings.

(Embodiment 1)
1.1 Configuration of Air Battery FIG. 1 is a perspective view showing an appearance of an air battery 1001 that is a zinc-air battery. For convenience of explanation, the vertical direction of the air battery 1001 is defined as the Z-axis direction, the thickness direction is defined as the X-axis direction, and the horizontal direction is defined as the Y-axis direction. In the following drawings, the X-axis direction, the Y-axis direction, and the Z-axis direction are used in this sense.

  FIG. 2 is an exploded view showing the air battery 1001 in FIG. FIG. 3 is a cross-sectional view of the air battery 1001 cut along the XZ plane at a position where a negative electrode lead terminal 311 described later is present.

  As shown in FIG. 2, a water repellent film 103, a discharge cathode catalyst layer 102, and a discharge cathode current collector 101 are attached to the inner surface 501 i of the first main wall 501. The discharge positive electrode current collector 101 and the discharge positive electrode catalyst layer 102 constitute a discharge positive electrode 100.

  A discharge positive electrode current collector 106, a discharge positive electrode catalyst layer 107, and a water repellent film 108 are attached to the inner surface 506 i of the second main wall 506. The discharge positive electrode current collector 106 and the discharge positive electrode catalyst layer 107 constitute a discharge positive electrode 105. A separator case 400 including a negative electrode current collector 301 and active material layers 302 and 303 is provided between the discharge positive electrode current collector 101 and the discharge positive electrode current collector 106. The negative electrode current collector 301 and the active material layers 302 and 303 constitute the metal negative electrode 300. The positive electrode current collectors 101 and 106 for discharge and the negative electrode current collector 301 are arranged in the X-axis direction while maintaining a substantially parallel relationship.

(Discharge positive electrode current collectors 101 and 106)
The discharge positive electrode current collectors 101 and 106 are electrically connected to the discharge positive electrode lead terminals 111 and 112, respectively, and supply charges generated in the discharge positive electrode catalyst layers 102 and 107 to an external circuit (not shown). .

(Discharge positive electrode catalyst layers 102 and 107)
The discharge positive electrode catalyst layers 102 and 107 are composed of a conductive porous carrier and a catalyst supported on the porous carrier, and form a three-phase interface in which oxygen gas, water, and electrons coexist, and In response to the supply of oxygen from the gas intake hole 501h formed in the main wall 501 and the gas intake hole 506h formed in the second main wall 506, the discharge reaction proceeds.

(Separator case 400)
Separator case 400 is a bag-like body constituted by a diaphragm that does not pass through the active material and its reaction product and only passes through the electrolytic solution. As shown in FIG. 3, the bottom portion 409 of the separator case 400 is a gusset surface, and the upper ends 401 and 402 are sealed.

(Negative electrode current collector 301)
The negative electrode current collector 301 has a negative electrode lead terminal 311 attached to the upper end thereof, and is accommodated in the separator case 400.

(Active material layers 302 and 303)
The active material layers 302 and 303 are formed in contact with the first negative electrode surface 312 and the second negative electrode surface 313 of the negative electrode current collector 301 as shown in FIG. The active material layers 302 and 303 are porous conductive materials made of active material particles, and the electrolyte solution penetrates into the gaps between the particles of the active material particles, thereby widening the contact interface between the active material particles and the electrolyte solution. A chemical reaction involving the active material and hydroxide ions (OH ⁻ ) is generated at the secured contact interface.

  FIG. 4 shows the negative electrode current collector 301 and the active material layer 303 extracted from the metal negative electrode 300 and shows them together with the positive electrode current collector 106 for discharge. “F (Z)” in FIG. 4 is a function that defines the thickness of the active material at an arbitrary position on the Z-axis. In the example of FIG. 4, F (Zn), F (Za), and F (Zb) are shown as the thicknesses of the three positions (positions Zn, Za, and Zb) on the Z-axis. The thicknesses of the active material layer 302 and the active material layer 303 are the shortest distances from the first negative electrode surface 312 and the negative electrode 313 of the negative electrode current collector 301 to the liquid surface of the electrolytic solution, respectively.

  In FIG. 4, at the position Zn, which is in the immediate vicinity of the attachment portion of the negative electrode lead terminal 311, the path length of the current flowing from the negative electrode lead terminal 311 through the negative electrode current collector 301 is short (En), but the electron conduction resistance is small. The thickness of the active material is small (see F (Zn) in FIG. 4), the distance from the discharge positive electrode current collector 101 is wide (see DF (Zn) in FIG. 4), and the ion conduction resistance is large. Become.

  On the other hand, at the position Zb, the path length of the current flowing through the negative electrode current collector 301 from the attachment position of the negative electrode lead terminal 311 is long (Eb) and the electron conduction resistance is large, but the thickness of the active material is large ( 4 (see F (Zb)> F (Zn) in FIG. 4), and the distance from the discharge positive electrode current collector 101 is narrow (see DF (Zb) in FIG. 4), the ion conduction resistance is small. Become. Therefore, the amount of current is balanced between the path Pa1 from the surface of the discharge positive electrode current collector 106 to the position Zn closest to the negative electrode lead terminal 311 and the path Pa2 from the negative electrode lead terminal 311 to the position Zb. doing.

  The thickness of the active material in the active material layer 303 is gradually increased from the attachment position of the negative electrode lead terminal 311 toward the far side (F (Zb)> F (Za)> F (Zn)). Since the distance from the electric body 106 is narrow (DF (Zb) <DF (Za) <DF (Zn)), the current flow at a position away from the attachment position of the negative electrode lead terminal 311. A positional bias in the ease of current flow, in which the ease is biased to any of a plurality of positions in the Z-axis direction, is suppressed. As a result, the amount of current flowing from the surface of the discharge positive electrode current collector 106 to the surface of the negative electrode current collector 301 approaches equally at each of a plurality of positions in the Z-axis direction.

  The method for measuring the thickness of the active material layers 302 and 303 can be measured by observing the XZ cross section of the air battery by X-ray tomography.

1.2 Chemical Reaction During Discharge Hereinafter, a chemical reaction during discharge of the air battery 1001 will be described.
In the metal negative electrode 300, a chemical reaction occurs between the hydroxide ions generated in the discharge positive electrode 100 and the active material particles in the active material layers 302 and 303. When the active material particles are zinc, zinc is oxidized and zincate ions are generated. Electrons are emitted during the formation of zincate ions. The emitted electrons are supplied from the metal negative electrode 300 to the discharge positive electrode 100. The zincate ions are precipitated as zinc oxide which is a reaction product.

  In the positive electrode current collector 101 for discharge, oxygen taken in from the outside through the gas intake holes 501h of the first main wall 501 shown in FIG. 2 reacts with water and electrons supplied from the metal negative electrode 300. This produces hydroxide ions.

  In FIG. 4, when the region from Zn to Za on the Z axis is the first region 321 and the region from Za to Zb is the second region 322, the contribution of the electron conduction resistance is small in the first region 321. The contribution of ion conduction resistance is large. On the other hand, in the second region 322, the contribution of the electron conduction resistance is large and the contribution of the ion conduction resistance is small. Therefore, the deposition of zinc oxide, which is a reaction product, occurs evenly in each of the first region 321 near the negative electrode lead terminal 311 and the second region 322 far from the negative electrode lead terminal 311, and the reaction product is deposited. , The concentration is not concentrated on the portion near the negative electrode lead terminal 311. Since the stress due to the expansion of the metal negative electrode 300 is dispersed in a plurality of locations, the outer container 500 can be prevented from being broken.

  The size of the first region 321 in the Z-axis direction (the gravitational direction in a state where the metal-air battery 1001 is placed on a horizontal surface with the negative electrode terminal lead 311 facing up) is the Z-axis direction of the negative electrode current collector 301. The distance is preferably set to ½ or less of the distance from the attachment position of the negative electrode lead terminal 311 to the other end in the Z-axis direction, and more preferably ¼ or less. The size of the second region 322 in the Z-axis direction is preferably set to ½ to 3/4 of the distance from the attachment position of the negative electrode lead terminal 311 to the other end in the Z-axis direction.

1.3 Manufacturing Method of Air Battery Next, a manufacturing method of the metal air battery 1 will be described. FIG. 5 is a process diagram showing a manufacturing process of the air battery 1001 according to the first embodiment.

  In step S101, the water repellent film 103 is overlaid on the inner surface 501i of the first main wall 501 of the outer container 500 as shown by the arrow ov1 in FIG. And the water repellent film 103 are integrated.

  In the subsequent step S102, the discharge positive electrode catalyst layer 102 and the discharge positive electrode current collector 101 are superimposed on the integrated first main wall 501 and water repellent film 103 as indicated by an arrow ov2 in FIG. 6B. By combining and subjecting to press working, these are integrated.

  When an alkaline aqueous solution is used as the electrolytic solution, the discharge positive electrode current collector 101 is a material obtained by applying nickel plating to the surface of a metal material such as nickel (Ni) or stainless steel (SUS) from the viewpoint of corrosion resistance. It is desirable to use The discharge positive electrode current collector 101 can be made porous by using a mesh, an expanded metal, a punching metal, a sintered body of metal particles or metal fibers, a foam metal, or the like.

  As a catalyst supported by the positive electrode catalyst layer for discharge, a catalyst generally used in the technical field of air batteries can be used. For example, platinum (Pt), manganese (Mn), lanthanum (La), titanium (Ti ), One or more metals such as cobalt (Co), or metal oxides such as iron, nickel, titanium, copper, ruthenium, selenium, tungsten, vanadium, molybdenum, manganese, niobium, and metal hydroxides. Can do. For example, polytetrafluoroethylene (PTFE) is preferable as the water-repellent resin of the water-repellent film 103.

  The same processing is performed on the second main wall 506 of the outer container 500, and as shown in FIG. 6C, the water repellent film 108, the discharge positive electrode catalyst layer 107, and the discharge The positive electrode current collector 106 is integrated.

  The positive electrode lead terminals 111 and 112 for discharge are made of heat-resistant material made of polyimide (PI) resin, polyphenylene sulfide (PPS) resin, etc. on a lead body (which may be an alloy thereof) made of aluminum, nickel, titanium, stainless steel, or copper. It is configured by providing an insulating part. The negative electrode lead terminal 311 has the same configuration.

  In parallel with the above steps S101 and S102, steps S103 and S104 are executed. In step S103, a bag-shaped separator case 400 having a gusset surface at the bottom is formed. Hereinafter, the process of forming the separator case 400 will be described in detail.

  First, a porous film material for forming the separator case 400 is prepared. As such a film material, a single layer structure composed only of a heat-weldable film or a multilayer structure in which a heat-weldable film and a heat-resistant substrate are laminated can be used.

  Specifically, polyolefin resin materials such as polypropylene (PP), polyvinyl alcohol (PVA), polyethylene (PE), and polytetrafluoroethylene (PTFE) can be used as the heat-welding film. As the heat-resistant substrate, it is preferable to include a heat-resistant synthetic resin-based material. For example, polyolefin resins such as nylon, polyethylene terephthalate (PET), polybutylene terephthalate (PBT) can be suitably used. .

  As shown by fd1 and fd2 in FIG. 7A, the left end 421 and the right end 422 of the film material 420 are folded, and the right end 422 is overlapped with the left end 421 and thermally welded to form a cylinder.

  Next, as shown in FIG. 7B, the lower end 423 of the tubular film material 420 is bent as indicated by an arrow fd3. Further, as shown in FIG. 7C, the sheet materials 424 and 425 overlapped at the lower end 423 of the film material 420 are opened as indicated by arrows op1 and op2, and as indicated by arrows td5 and td6 in FIG. 7D. Then, the sheet materials 424 and 425 are folded and overlapped and thermally welded, whereby the town surface of the bottom portion 409 of the separator case 400 shown in FIG. 3 is completed.

  Further, left and right side portions 426 and 427 shown in FIG. 7E are formed to complete the separator case 400. The separator case 400 has a shape in which the thickness increases from the upper end 401 of the separator case toward the bottom face. If the separator case 400 with the bottom surface is completed, the process proceeds to step S104.

  In step S <b> 104, the negative electrode current collector 301 is inserted into the separator case 400 and an active material that is a raw material of the active material layers 302 and 303 is injected. Specifically, as shown in FIG. 7 (f), the negative electrode current collector 301 to which the negative electrode lead terminal 311 is attached is inserted into the separator case 400, and the active material particles 302m and the binder 302b are inserted into the separator case. Inject from the upper end 401 of 400.

As the binder 302b, polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF) can be used. Moreover, you may use a gel material,
The negative electrode current collector 301 is desirably formed of a porous material having electron conductivity. From the standpoint of suppressing self-corrosion, a material having a high hydrogen overvoltage such as copper or tin or a material obtained by plating a metal material surface such as stainless steel with a material having a high hydrogen overvoltage is used as the negative electrode current collector 301. Is desirable. The negative electrode current collector 301 is preferably made of the same material as the positive electrode current collectors 101 and 106 for discharge, that is, a mesh, expanded metal, punching metal, metal particle or metal fiber sintered body, and foam metal. Can be used.

  As the active material particles included in the active material layers 302 and 303, reduced metal particles or oxidized particles may be used. As the metal particles in the reduced state, metal metal powder such as zinc (Zn), magnesium (Mg), aluminum (Al), and lithium (Li) is used. When the active material particles contain zinc (Zn), reduced metal zinc particles may be used, or oxidized zinc oxide or zinc hydroxide particles may be used. In addition, you may inject | pour into the separator case 400 not only an active material metal particle but the gel-like active material metal particle. In addition to the active material particles, the active material layers 302 and 303 may include a binder that binds the active material particles and a conductive additive that improves the conductivity of the active material layer. The binder and the conductive additive are not particularly limited, and may be appropriately selected from those generally used in the technical field of air batteries.

  By injecting the binder 302b together with the active material particles 302m, the active material is solidified inside the separator case 400 having the bottom 409 as a gusset surface. Then, the active material layers 302 and 303 are formed in such a shape that the thickness of the active material increases as the distance from the negative electrode lead terminal 311 increases. When solidification of the injected active material is completed in this way, the metal negative electrode 300 and the separator case 400 are completed.

  When the metal negative electrode 300 is completed, the process of step S105 is performed. Specifically, as shown in FIG. 6 (d), the inner surface 501i of the first main wall and the inner surface 506i of the second main wall are opposed to each other, and the separator case 400 is set as shown by arrows bd1 and bd2. Sandwich.

  In step S106, the electrolyte solution is injected and the separator case 400 is sealed. Specifically, as indicated by an arrow ij1 in FIG. 6E, an electrolytic solution is injected into the separator case 400 from the upper end 401 of the separator case 400, and the metal negative electrode 300 is immersed in the electrolytic solution.

  As the electrolytic solution, an alkaline aqueous solution, salt water, an organic solution, or the like can be used.

  With the negative electrode lead terminal 311 conducting to the metal negative electrode 300 protruding from the upper end 401 of the separator case 400, the inner side of the upper end 401 in FIG. 6E is thermally welded to seal the upper end 401.

  Next, sandwiching the separator case 400, the left and right edges 502, 503, 507, 508, and the lower edges 504, 509 of the first main wall 501, the second main wall 506 are thermally welded, Make it an integrated state. Thereby, the bottomed bag-shaped exterior container 500 having an open top is formed.

  Further, in a state where the discharge positive electrode lead terminals 111 and 112 and the negative electrode lead terminal 311 are projected from the upper end 511 of the outer casing 500, the inner surface 501i and the second inner wall 501i of the first main wall 501 in FIG. An electrolyte is injected between the inner surface 506 i of the main wall 506 and the outer surface of the separator case 400. Finally, the outer container 500 is sealed by thermally welding the outer surface of the upper end 401 of the separator case 400 and the inner surface of the upper end 401 of the outer container 500. The sealing of the separator case 400 and the sealing of the outer container 500 can be performed at the same time.

4). Summary In the negative electrode current collector 301 of FIG. 4, the thickness Zn of the active material layer 303 in the portion Zn immediately adjacent to the portion where the negative electrode lead terminal 311 is attached is minimized. On the other hand, since the distance DF (Zn) between the metal negative electrode 300 and the discharge positive electrode 100 is maximized, as a result, the ion conduction resistance due to the electrolyte is maximized in the portion Zn immediately adjacent to the negative electrode lead terminal 311. . The path length of the current flowing from the negative electrode lead terminal 311 through the negative electrode current collector 301 is the minimum in the path (En) reaching the position Zn that is in the immediate vicinity of the attachment portion of the negative electrode lead terminal 311. Conversely, the path length of the current flowing from the negative electrode lead terminal 311 through the negative electrode current collector 301 is maximized in the path (Eb) reaching the position Zb on the other end side of the negative electrode current collector 301.

  In general, the current flowing from the negative electrode to each part of the positive electrode in an air battery is determined by the contribution of both the current path length on the current collector from the lead terminal and the ionic conduction resistance of the electrolyte. In the air battery 1001, although the path length of the current path (En) reaching the position Zn closest to the negative electrode lead terminal 311 is short, the distance from the discharge positive electrode 100 is greatly widened (D-F ( Zn)), ion conduction resistance is high. On the other hand, the current path (Eb) leading to the position Zb far from the negative electrode lead terminal 311 has a long path length, but the distance from the positive electrode 100 for discharge is narrowed (DF (Zb in the figure)). )), Low ion conduction resistance.

  Since the active material layer 303 is inclined so that the ionic conduction resistance is low in a path having a large current path length on the current collector, the air battery 1001 is disposed in the vicinity of the negative electrode lead terminal 311 from the positive electrode for discharge. The current value flowing through 100 and the current value flowing through the discharge positive electrode 100 from a location far from the negative lead terminal 311 can be balanced. As a result, the amount of reaction product produced is also balanced between the electrolyte near the lead terminal and the electrolyte far from the lead terminal. Therefore, the reaction product is generated at a uniform frequency throughout the negative electrode.

  Therefore, in the air battery 1001, even when the metal negative electrode 300 expands due to the deposition of the active material, the entire negative electrode can be expanded at a substantially equal ratio. Since the stress due to the expansion of the negative electrode is dispersed throughout the negative electrode, the outer container 500 can be prevented from being broken and the electrolyte solution can be prevented from leaking.

  Further, in the present disclosure, as the thickness of the active material layer 302 and the active material layer 303 is increased as approaching in the negative Z-axis direction (below the air battery 1001), the stability when using the air battery in a standing posture is increased. Can be improved.

(Embodiment 2)
In the first embodiment, a metal-air battery in which a metal negative electrode 300 is disposed between the discharge positive electrodes 100 and 105 is configured. On the other hand, Embodiment 2 constitutes a metal-air battery in which the discharge positive electrode 100 and the metal negative electrode 300 are paired.

2.1 Configuration of Air Battery FIG. 8A is a perspective view of the air battery 1002 according to Embodiment 2, and FIG. 8B is a case where the air battery 1002 is cut at the same position as in FIG. FIG.

  In Embodiment 2, as shown in FIG. 8B, the active material layer 302 is formed only on the first negative electrode surface 312 side of the negative electrode current collector 301. An active material layer is not formed on the second negative electrode surface 313. The active material layer 302 formed on the first negative electrode surface 312 is the same as that described in Embodiment 1, and the thickness of the active material increases as the position in the Z-axis direction advances. A negative electrode active material layer is not formed on the second negative electrode surface 313, and a laminate sheet 521 is attached instead.

2.2 Summary Since the discharge positive electrode is formed only on the first main wall 501 side of the air battery 1002, the laminate sheet 521 of the air battery 1002 is disposed on the first main wall 501 side. Since the strength is higher than that of the water-repellent film 103, the air battery 1002 is less likely to be damaged even if an impact is applied to the laminate sheet 521 side. Thereby, the risk of breakage when the air battery 1002 receives an impact can be reduced.

(Embodiment 3)
In the first embodiment, the discharge positive electrodes 100 and 105 are opposed to the active material layers 302 and 303, respectively. However, in the third embodiment, the charge positive electrode is opposed to the active material layer 303 and the charge / discharge function is exhibited. Construct an air battery. As shown in FIG. 9B, the air battery according to Embodiment 3 is tripolar air including a metal negative electrode 300, a discharge positive electrode 100, and a charge positive electrode 200.

3.1 Configuration of Air Battery FIG. 9A is a perspective view of a three-pole air battery 1003 according to the third embodiment. FIG. 9B is a cross-sectional view of the tripolar air battery 1003. As shown in FIG. 9B, the second negative electrode surface 313 of the negative electrode current collector 301 of Embodiment 3 faces the charging positive electrode 200. As shown in FIG. 9B, the charging positive electrode 200 includes a charging positive electrode current collector 201 and a water repellent film 202.

(Charging positive electrode current collector 201)
The positive electrode current collector for charging 201 is supplied with charges necessary for a charging reaction from an external circuit (not shown) via the positive electrode lead terminal for charging 211, so that oxygen (gas phase), water (liquid phase), The charging reaction proceeds at the three-phase interface where the electron conductor (solid phase) coexists. This charging reaction is a chemical reaction that generates oxygen, water, and electrons from hydroxide ions (OH ⁻ ) contained in an alkaline aqueous solution that is an electrolytic solution. In the third embodiment, the gas intake hole 506h formed in the second main wall 506 shown in FIG. 2 has a function as a gas discharge hole (referred to as a gas discharge hole 506h), and charging is performed. The positive electrode current collector 201 promotes the discharge of oxygen gas generated by the charging reaction through the gas discharge hole 506h.

(Water repellent film 202)
The water-repellent film 202 is disposed between the charging positive electrode current collector 201 and the outer container 501, and suppresses leakage of the electrolyte solution via the charging positive electrode 200. Further, a gas such as oxygen gas generated by the charging reaction is separated from the electrolytic solution, and discharge from the gas discharge hole 506h is promoted.

3.2 Chemical Reaction During Charging During charging, a precipitation reaction of zinc metal molecules occurs in the active material layers 302 and 303 of the metal negative electrode 300. By such a precipitation reaction, zinc metal molecules are deposited on the active material layers 302 and 303, and the volume of the negative electrode active material increases.

  As in the first embodiment, the active material layers 302 and 303 have an inclined shape in which the thickness decreases near the negative electrode lead terminal 311 and increases as the distance from the negative electrode lead terminal 311 increases. The generation location is not biased to the mounting position of the negative electrode lead terminal 311. Since the deposition of zinc metal molecules occurs at a position 301e on the other end side as shown in FIG. 9A, which is far from the attachment position of the negative electrode lead terminal 311, the active material layers 302 and 303 have an equal ratio over the entire area. Inflates with.

3.3 Manufacturing Method Next, a manufacturing method of the tripolar air battery 1003 will be described.

  In manufacturing the three-pole air battery 1003, the water repellent film 202 is attached to the inner surface of the second main wall 506 by heat welding, and the charging positive electrode current collector 201 is attached to the second main wall 506 by pressing.

  The charging positive electrode 200 is desirably a porous material having electron conductivity. When an alkaline aqueous solution is used as the electrolytic solution, it is desirable to use nickel (Ni), stainless steel (SUS), or the like from the viewpoints of corrosion resistance and oxygen generation catalytic ability for a charging reaction. By using a mesh, an expanded metal, a punching metal, a sintered body of metal particles or metal fibers, a foamed metal, or the like as the charging positive electrode 200, the charging positive electrode 200 can be made porous. The positive electrode for charging 200 may include oxygen generating catalyst particles that promote a charging reaction on the surface. Further, the charging positive electrode lead terminal 211 can have the same configuration as the charging positive electrode lead terminal 211.

3.4 Summary As in the first embodiment, the active material layer 303 facing the charging positive electrode 200 has a large thickness at a position far from the negative lead terminal 311 and a small thickness at a close position. Ease of flow is uniform both at a position far from and close to the negative electrode lead terminal 311, and the expansion of the negative electrode due to the precipitation reaction has the same frequency at a position far from the negative electrode lead terminal 311 and at a close position. Occurs. Since the stress due to the expansion of the negative electrode is dispersed, it is possible to avoid breakage of the outer container 500 in the charging reaction.

  Moreover, the thickness of the active material layer 303 is large at a position far from the negative electrode lead terminal 311, and the charging positive electrode 200 faces slightly upward. The inclination of the charging positive electrode increases the efficiency of oxygen uptake by the charging positive electrode 200, so that the charging reaction in the charging positive electrode 200 can be promoted.

4). Other Modifications The present invention is not limited to the above embodiment. You may make it show below.

  (1) The shape of the active material layers 302 and 303 in each embodiment is not limited to the inclined shape shown in FIGS. In FIG. 4, any shape may be used as long as the maximum active material thickness in the second region 322 exceeds the maximum active material thickness in the first region 321. The thickness of the active material in the first region 321 may be uniform throughout the Z-axis direction, and the thickness may be increased only in a part of the second region 322. In addition, if the maximum thickness of the second region 322 exceeds the maximum thickness of the first region 321, the thickness of the first region 321 becomes maximum in the middle from the position of Zn to the position of Za in FIG. 4. It may be.

  (2) The cross-sectional shape when the metal negative electrode 300 is cut at a plurality of positions in the Z-axis direction may be different depending on the position. FIG. 10A shows a cross section of the metal negative electrode according to the modification. As shown in this figure, the metal negative electrode according to this modification has an active material layer 342 on the first negative electrode surface 312 side of the negative electrode current collector 301 and an active material layer 343 on the second negative electrode surface 313 side. Is formed. FIGS. 10B and 10C are cross-sectional views taken along lines AA ′ and BB ′ in the positive direction of the Z-axis. Although the cross-sectional shapes are different, the cross-sectional areas Sg of the active material layers 342 and 343 shown in FIG. 10C are formed to be larger than the cross-sectional areas Sf of the active material layers 342 and 343 shown in FIG. ing. Since the cross-sectional areas of the active material layers 342 and 343 are set in this way, the amount of current flowing through the position 301f far from the negative electrode lead terminal 311 due to the increase in the cross-sectional area is the position 301n near the negative electrode lead terminal 311, This is the same as the intermediate position 301m. By enlarging the cross-sectional area, the ease of current flow at a position far from the negative electrode lead terminal 311 is ensured, so that the degree of freedom in forming the active material layers 342 and 343 is increased.

  (3) The inclined shape of the active material layers 302 and 303 in the positive Z-axis direction may form a monotonously increasing function F (Z). The monotonic increase function F (Z) is a linear function of the form F (Z) = A · Z + B, and the coefficient A is set to a value corresponding to the resistivity of the negative electrode current collector 301. By setting the coefficient A to a value corresponding to the resistivity of the discharge positive electrode current collector 101 and the negative electrode current collector 301, the ion conduction resistance between the negative electrode current collector 301 and the discharge positive electrode current collector 101 is In order to cancel out the ohmic loss caused by moving away from the negative electrode lead terminal 311, it decreases monotonously. By monotonically decreasing the ionic conduction resistance so as to cancel out the ohmic loss, it becomes possible to secure an amount of current flowing through a position away from the negative electrode lead terminal 311.

  (4) In the first embodiment, the active material powders 302 and 303 are obtained by inserting the active material powder into the separator case 400 and solidifying it. However, by solidifying the active material and the reaction product thereof, Alternatively, an active material lump may be obtained, and the active material lump may be processed into the inclined shape shown in FIGS. 3 and 5 to obtain the active material layer 302 and the active material layer 303. After the active material layer 302 and the active material layer 303 thus obtained were attached to the negative electrode current collector 301 and inserted from the upper end opening of the separator case which is a bag-shaped body having no bottom surface, the electrolyte was injected. The upper end of the separator case is sealed. Since the active material layer 302 and the active material layer 303 are formed in a process such as mold forming or metal cutting, the forming accuracy of the active material layer 302 and the active material layer 303 can be increased, and the frequency of occurrence of chemical reaction is uneven. It is suppressed.

  (5) The metal air battery may be an aluminum air battery, an iron air battery, a magnesium air battery, or a lithium air battery. In these air batteries, an alkaline aqueous solution such as an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution can be used as an electrolytic solution. In the case of a magnesium air battery, an aqueous sodium chloride solution can be used as the electrolyte, and in the case of a lithium air battery, an organic electrolyte can be used. An organic additive or an inorganic additive other than the electrolyte may be added to the electrolytic solution, or it may be gelled with a polymer additive.

  (6) The present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Embodiments to be included are also included in the technical scope of the present disclosure.

  The present disclosure can be widely used for metal-air batteries used as one of power supply apparatuses.

100, 105 Discharge positive electrode 101, 106 Discharge positive electrode current collector 102, 107 Discharge positive electrode catalyst layer 103, 108 Water repellent film 111, 112 Discharge positive electrode lead terminal 200 Charge positive electrode 201 Charge positive electrode current collector 202 Repellent Water film 211 Charging positive electrode lead terminal 300 Metal negative electrode 301 Negative electrode current collector 302, 303 Active material layer 311 Negative electrode lead terminal 400 Separator case 500 Outer container 521 Laminate sheet 1001, 1002 Air battery 1003 Tripolar air battery

Claims (17)

An air battery in which an electrolyte container, a positive electrode that is an air electrode, and a negative electrode are housed in an outer container of a multilayer structure including a layer having a vent and a layer having water repellency. A body, a lead terminal attached to one end of the current collector, and an active material layer formed on the remaining portion of the current collector,
The said active material layer has a part which thickness increases toward the direction away from the attachment position side of the said lead terminal among the said electrical power collectors. The air battery characterized by the above-mentioned. The active material layer is thinnest at the portion closest to the mounting position of the lead terminal, and has a portion that increases in thickness toward the other end of the current collector, except for the portion closest to the mounting position of the lead terminal. The air battery according to claim 1. The air battery according to claim 1, wherein the air battery has a portion that becomes narrower as a distance between the surface of the active material layer and the positive electrode becomes farther from the attachment position of the lead terminal. The negative electrode is housed in an outer container together with an electrolytic solution in a state covered with a bag-like body,
The bag-like body is a diaphragm that does not permeate the reaction product of the active material and permeates the electrolyte, and has an insulating property.
The air battery according to any one of claims 1 to 3, wherein the lead terminal protrudes outward from the bag state. The air battery according to claim 4, wherein the bag-like body has a gusseted surface at the bottom. The active material layer is formed on one side surface and the other side surface of the current collector, the positive electrode includes a first positive electrode facing the one side surface of the current collector, and the other side A second positive electrode facing the side surface,
The said 1st, 2nd positive electrode is a positive electrode for discharge, and contains the catalyst layer comprised by the catalyst for discharge reaction, and the porous support | carrier which supported the catalyst. The air battery according to any one of the above. The active material layer is formed on one side surface of the current collector, the positive electrode is a positive electrode for discharge, and faces one side surface of the current collector, for discharge reaction. Including a catalyst layer composed of a catalyst and a porous carrier carrying the catalyst;
The air battery according to claim 1, wherein the other surface of the current collector is attached to an exterior container. The active material layer is formed on one side surface of the current collector, the positive electrode is a positive electrode for discharge, and faces one side surface of the current collector, for discharge reaction. Including a catalyst layer composed of a catalyst and a porous carrier carrying the catalyst;
The air battery according to any one of claims 1 to 5, wherein the other surface of the current collector faces the charging positive electrode. Of the negative electrode, the portion excluding one end where the lead terminal is attached is composed of a first layer region on the side close to the lead terminal and a second layer region on the side far from the lead terminal,
The portion where the thickness of the active material increases toward the other end of the current collector is located in the second layer region, and the cross-sectional area when the active material layer is cut at the apex portion is that of the first layer region. 2. The air battery according to claim 1, wherein the air cell has a cross-sectional area larger than that obtained when the active material layer is cut at any portion. The first region is a range from the attachment position of the negative electrode lead terminal to ½ or less from the other end to the other end,
10. The metal-air battery according to claim 9, wherein the second region is a range of ½ or more from the attachment position of the negative electrode lead terminal. A method of manufacturing an air battery,
A forming step of attaching a lead terminal to one end of the current collector and forming an active material layer on the remaining part,
A housing step of housing the negative electrode and the positive electrode in an outer container of a multilayer structure including a layer having a vent and a layer having water repellency;
Including an injection step of injecting an electrolyte into the outer container,
In forming the active material layer in the forming step, a portion where the thickness of the active material layer increases in a direction away from the mounting position side of the lead terminal is formed. In forming the active material layer in the forming step, the portion closest to the lead terminal attachment position is the thinnest, and the portion excluding the portion closest to the lead terminal attachment position is directed toward the other end of the current collector. A portion for increasing the thickness of the active material layer is formed. The method of manufacturing an air battery according to claim 11. In the forming step, the active material or a reaction product thereof is injected into a bag-like body having a gusset surface at the bottom, and solidified, so that the thickness of the active material is increased toward the other end of the current collector. Forming an additional portion in the active material layer;
In the housing step, the active material layer is covered with a bag-like body and housed in an outer container,
The method for producing an air battery according to claim 11 or 12, wherein the bag-like body is a diaphragm that does not transmit a reaction product of the active material but transmits an electrolytic solution, and has an insulating property. In the forming step, the active material or a reaction product obtained by solidifying the active material is attached to the current collector, so that a portion where the thickness of the active material increases toward the other end of the current collector is the active material. Formed in layers, covered with a bag,
The air according to any one of claims 11 to 13, wherein the bag-like body is a diaphragm that does not transmit a reaction product of the active material but transmits an electrolytic solution, and has an insulating property. Battery manufacturing method. In the forming step, an active material layer is formed on one surface and the other surface of the current collector,
The positive electrode is composed of a first positive electrode and a second positive electrode,
In the housing step, the first positive electrode, the second positive electrode, and the negative electrode are placed on the outer container so that the first positive electrode faces the one surface of the current collector, the second positive electrode faces the other surface, Contain,
The said 1st, 2nd positive electrode is a positive electrode for discharge, and contains the catalyst layer comprised by the catalyst for discharge reaction, and the porous support | carrier which carried the catalyst. The manufacturing method of the air battery as described in any one of these. The active material layer is formed on one surface of the current collector, and the positive electrode is a positive electrode for discharge, and includes a catalyst for a discharge reaction and a porous carrier that supports the catalyst. Including a catalyst layer,
The accommodating step is characterized in that a discharge positive electrode is opposed to one surface of the current collector on which an active material layer is formed, and the other surface of the current collector is attached with an outer container. The method for manufacturing an air battery according to any one of claims 11 to 13. In the forming step, the active material layer is formed on one surface of the current collector,
The positive electrode is a positive electrode for discharge, and the housing step is opposed to one surface of the current collector, and the positive electrode for charging is opposed to the other surface of the current collector,
The air according to any one of claims 10 to 13, wherein the discharge positive electrode includes a catalyst layer including a catalyst for a discharge reaction and a porous carrier carrying the catalyst. Battery manufacturing method.

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