DE102014209784A1 - CATHODE STRUCTURE OF A LITHIUM AIR ACCUMULATOR AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Abstract

A lithium-air battery has a cathode with a structure having a cathode terminal and a flat-like air electrode collector containing a carbon fiber, the air electrode collector and the cathode terminal being in a state of contacting the cathode terminal with the air electrode collector be heat-welded with a thermoplastic resin, and a peripheral edge portion of the air electrode collector is impregnated with the thermosetting resin.

Description

Background of the invention

Field of the invention

The present invention relates to a structure of a cathode of a lithium-air secondary battery having a cathode terminal and a flat-plate type air electrode collector including a carbon fiber, and a method of fabricating the cathode of the lithium-air secondary battery.

State of the art

A lithium-air battery or a lithium-air cell uses lithium metal as the active anode material and uses oxygen in the air as the active air-electrode (cathode) material. In theory, the lithium-air battery has a high energy density, and is expected to be capable of providing an energy density many times higher than that of a lithium-ion battery, such as for the broad Distribution of electric vehicles or battery-powered cars is needed.

The lithium-air batteries can be roughly divided into lithium-air batteries, which make use of an aqueous electrolyte, and lithium-air batteries, which make use of a nonaqueous electrolyte. Although research and development in the past has focused mainly on non-aqueous electrolyte lithium-air batteries and simple accumulator construction, aqueous-electrolyte lithium-air batteries are being researched for the following reasons. The aqueous electrolyte lithium-air secondary battery has advantages in theoretical energy density higher than that of the non-aqueous electrolyte lithium-air secondary battery, and the electrolytes are inexpensive and non-combustible. In particular, a lithium-air secondary battery having a laminated cell structure has been proposed as an accumulator cell for more effectively utilizing the high energy density advantage.

The lithium-air secondary battery having a laminated cell structure using an aqueous electrolyte is disclosed, for example, in Non-Patent Document 1 (FIG. Report by GS Yuasa Corporation "Present Status and Issues for Lithium / Air Battery Using Aqueous Electrolyte" (June 2010) ) and in patent document 1 ( Japanese Patent Laid-Open Publication No. 2010-192313 ) disclosed.

8th illustrates a lithium-air battery 100 as shown in Non-Patent Document 1. The lithium-air battery 100 contains a cathode 101 , a composite anode 102 and an electrolyte 103 ,

The composite anode 102 contains an anode element 104 made of a material such as lithium metal, an anode terminal 105 from, for example, copper, an anode protective layer 106 , and an LTAP plate 107 from a material such as glass-ceramic. The cathode 101 contains a flat piece air-electrode collector 108 containing a carbon fiber, wherein the air-electrode collector 108 made in an example of a carbon cloth, also a metallic mesh 109 made of platinum, aluminum or nickel, the metallic mesh 109 on the air electrode collector 108 rests. The cathode 101 further includes a cathode terminal made of, for example, aluminum 110 , the one with the metallic mesh 109 connected is.

The electrolyte 103 is located between the above-explained cathode 101 and the composite anode 102 , The cathode 101 and the composite anode 102 are of gas barrier films 111 and 112 wrapped, for example, as aluminum laminate films and are on both sides in bag form to the lithium-air battery 100 to complete. The gas barrier film 111 is with an opening 113 equipped, which acts as an air intake.

The lithium-air secondary battery described in Patent Literature 1 is formed by accommodating in a box-like container in the following order: an anode, a buffer layer, a waterproof layer (glass-ceramic), an electrolyte, an air electrode (cathode) and a oxygen permeable material. In Patent Document 1, nothing is said about the structure of the cathode.

In the cathode 101 of the lithium-air battery 100 according to Non-Patent Document 1, this is with the cathode terminal 110 connected metallic meshes 109 at the air electrode collector 108 placed, causing insufficient adhesion between the air electrode collector 108 and the metallic mesh 109 comes what is the electrical conductivity of the lithium-air battery 100 deteriorated.

As in 9 is seen between a peripheral edge area 108A of the air electrode collector 108 and a peripheral portion of the opening 113 of the gas barrier film 111 a gap 114 present, so that the electrolyte 103 through the gap 114 can escape.

Due to lithium hydroxides and the like, which are caused by a cell reaction, also becomes the aqueous electrolyte 103 strongly alkaline. If the metallic mesh 109 is made of a material such as aluminum and / or nickel, the highly alkaline electrolyte corrodes 103 the metallic mesh 109 , If at the air-electrode collector 108 a corrosion product adheres, the electrical resistance of the air-electrode collector decreases 108 to, and as a result, one has expensive platinum with high corrosion resistance for the metallic mesh 109 which leads to increased costs of the lithium-air battery 100 leads.

As in 8th is shown, there is the air-electrode collector 108 for example, from a carbon cloth. Since the carbon cloth is fibrous, has the air-electrode collector 108 a low rigidity, which makes it difficult to use the air-electrode collector 108 with other elements such as the composite anode 102 align. As a result, one obtains only a low positioning accuracy for the air electrode collector 108 What the assembly of the lithium-air battery 100 difficult.

DISCLOSURE OF THE INVENTION

The present invention has been made in view of the above-described circumstances, and its object is to provide a structure of a cathode of a lithium-air secondary battery, in which an increased adhesiveness between an air-electrode collector and a cathode terminal is achieved, thereby increase electrical conductivity of the battery and at the same time to avoid leakage of the electrolyte from a peripheral edge region of the air-electrode collector. In addition, a manufacturing method for such a cathode of the lithium-air battery is to be specified.

The above-mentioned aim and other objects can be achieved according to the invention by providing according to one aspect: a cathode connection; and a sheet-like air electrode collector including a carbon fiber, wherein, in a state where the cathode terminal is in contact with the air electrode assembly, the air electrode collector and the cathode terminal are heat-sealed with a thermoplastic resin, and a peripheral edge portion of the air Electrode collector is impregnated with a thermosetting resin.

In this aspect, it may be preferable if the cathode terminal consists of a single substance of aluminum or nickel or an alloy thereof.

According to another aspect of the invention, there is provided a cathode terminal; and a sheet-like air-electrode collector including a carbon fiber, wherein the cathode terminal is formed integrally with the air-electrode collector, and a peripheral edge portion of the air-electrode collector is impregnated with a thermoplastic resin.

In this aspect, it may be preferable that the thermoplastic resin is welded to at least one surface of the cathode terminal.

In other aspects, it may also be preferable that the peripheral edge portion of the air-electrode collector is impregnated with a thermoplastic resin forming a frame-shaped resin film having an opening and a porous resin outside the air-electrode collector exposed outside the opening in the resin film is arranged with waterproof property and ventilation property.

The above object can also be achieved by providing, in another aspect, a method of manufacturing a cathode of a lithium-air secondary battery including the steps of: preparing a cathode terminal and a sheet-like air electrode collector including a carbon fiber; Contacting the air-electrode collector with the cathode port; Inserting a peripheral edge portion of the air-electrode collector and the cathode terminal between a plurality of resin-molded frame films of thermoplastic resin, the frame-shaped resin films having an opening; and heat-welding the air-electrode collector and the cathode terminal to the resin films, and impregnating the peripheral edge portion of the air-electrode collector with the thermoplastic resin.

According to another aspect of the present invention, there is also provided a method of fabricating a cathode of a lithium-air secondary battery, comprising the steps of: preparing a sheet-like air-electrode collector including a carbon fiber and a cathode terminal integrally molded with the air-electrode collector ; Inserting a peripheral edge portion of the air-electrode collector between a plurality of thermoplastic resin frame-shaped resin films, the frame-shaped resin films having an opening; and impregnating the peripheral edge portion of the air-electrode collector with the thermoplastic resin.

In the above methods, it may be preferable to further place a step of placing a porous resin having a waterproof property and a venting property outside the air-electrode collector, via the opening in FIG exposed to the resin films, simultaneously with or subsequent to the heat welding and / or the step of impregnation.

According to the present invention, in the structures and features as mentioned above, the air electrode collector and the cathode terminal are integrally formed by heat welding or by integrated molding. Accordingly, the adhesiveness between the air-electrode collector and the cathode terminal is improved, so that the electrical conductivity of the secondary battery can be improved. In addition, since the peripheral edge portion of the air-electrode collector is impregnated with a thermoplastic resin, the peripheral edge portion of the air-electrode collector forms a fluid-tight structure. This makes it possible to suppress leakage of the electrolyte from the peripheral edge portion.

The particularity and other characteristic features of the present invention will become more apparent from the following description with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

1 Fig. 13 is an exploded perspective view illustrating the construction of a lithium-air secondary battery to which a first embodiment of the structure of a cathode of a lithium-air secondary battery according to the invention is applied;

2 FIG. 12 is a perspective view showing the cathode structure according to FIG 1 illustrated;

3 is a cross-sectional view of the lithium-air battery in which the individual elements or parts of 1 laminated together;

4 Fig. 15 is a perspective view of a structure of a cathode of a lithium-air secondary battery to which a second embodiment of a structure of a cathode of a lithium-air secondary battery according to the invention is applied, the cathode of which 2 corresponds;

5A and 5B are a front view and a rear view of the cathode according to 4 ;

6 Fig. 12 is a cross-sectional view illustrating a lithium-air secondary battery to which a third embodiment of a structure of a cathode of a lithium-air secondary battery according to the invention is applied;

7 Fig. 12 is a cross-sectional view of a lithium-air secondary battery according to a modified version of the third embodiment;

8th Fig. 12 is an exploded perspective view illustrating a conventional lithium-air secondary battery; and

9 is a fragmentary sectional view of the in 8th shown lithium-air battery.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments for implementing the present invention will be described below with reference to the drawings. Further, it should be noted that terms such as "top", "bottom", "right", "left" and the like as used herein with respect to the state shown in the drawings or in relation to an assembled state of a lithium-air battery specify.

First Embodiment (FIGS. 1 to 3)

1 FIG. 10 is an exploded perspective view of a lithium-air secondary battery according to a first embodiment of the present invention. FIG. According to 1 contains a lithium-air battery 10 a laminated cell structure with a cathode 11 , a composite anode 12 and an electrolyte 13 , In this embodiment, the electrolyte is 13 an aqueous electrolyte, for example, a lithium chloride solution. The electrolyte 13 also acts to store a reaction product.

The composite structure 12 contains an anode element 14 , an anode connection 15 , an organic electrolyte solution 16 and an LTAP plate 17 , Resin films such as aluminum laminate films 18 and 19 encapsulate the above components in a bag-like shape. A TBF adhesive flat piece 20 is located between the aluminum laminate film 18 and the LTAP plate 17 ,

The anode element 14 It is composed of a single substance of lithium or sodium of an alkali metal group or the like, or is made of a compound thereof. Among these materials, lithium is particularly suitable for obtaining a high energy density accumulator. The anode element 14 In this embodiment, it consists of a single substance, namely lithium. The anode connection 15 that with the element 14 is composed of a metal of high electrical conductivity, for example copper.

The LTAP plate 17 , which is a separator, which is an air-electrode collector 22 (which will be described later) and the element 14 consists of a glass ceramic with high conductivity for lithium ions. The LTAP plate 17 also has the function, the penetration of water and the like to the element 14 to prevent. The TBF adhesive flat piece 20 binds the LTAP plate 17 on the aluminum laminate film 18 ,

The aluminum laminate films 18 and 19 include a refractory base material layer of a thermoplastic resin (for example, polyethylene terephthalate (PET)), an adhesive layer (for example, polypropylene (PP), polyethylene (PE), and ethylene vinyl acetate (EVA)) with an aluminum foil between the base material layer and the adhesive layer.

In the aluminum laminate film 18 the base material layer is on an upper side, the adhesive layer is on a lower side. In the aluminum laminate film 19 the adhesive layer is on the top and the base layer is on the bottom. By bonding the adhesive layers of the aluminum laminate films 18 and 19 each other becomes the element 14 , the organic electrolyte solution 16 and the LTAP plate 17 from the aluminum laminate films 18 and 19 as if wrapped in a bag, around the composite structure 12 to build.

As in the 1 to 3 is shown, contains the cathode 11 a cathode connection 21 and a sheet-like air-electrode collector 22 containing a carbon fiber. In a state in which a front side or a back side of the air-electrode collector 22 in contact with an end area 21A of the cathode connection 21 , are the air-electrode collector 22 and the cathode connection 21 with a thermoplastic resin heat-sealed (thermally fused), and the thermoplastic resin impregnates the entire peripheral edge portion 22A of the air electrode collector 22 , causing the cathode 11 is formed.

reference numeral 23 in the 2 and 3 denotes an impregnated zone in which the thermoplastic resin surrounds the peripheral edge portion 22A of the air electrode collector 22 impregnated. reference numeral 25 denotes a molten (welded) zone in which the end region 21A of the cathode connection 21 at the air electrode collector 22 heat-welded and fixed.

The cathode connection 21 consists of a single substance of aluminum or nickel or a compound thereof. The air electrode collector 22 consists of a material with electrical conductivity and gas diffusion, such as a carbon cloth, carbon paper, a non-woven carbon cloth material, porous nickel or porous aluminum. The air electrode collector 22 contains a catalyst (for example, platinum) and a binder for accelerating the reaction, as needed.

The carbon cloth consists essentially of a flat piece of regularly interwoven carbon fibers. The non-woven carbon cloth material is a sheet of arbitrarily interwoven carbon fibers. As electrons penetrate the carbon fibers, the carbon fibers have high electrical conductivity and their energy density is higher than that of metals. Therefore, the carbon fibers are for the air-electrode collector 22 the cathode 11 suitable. The air electrode collector 22 This first embodiment consists of a carbon cloth with a catalyst, such as platinum, incorporated therein.

The thermoplastic resin for use in heat-sealing the end portion 21A of the cathode connection 21 with the air electrode collector 22 and for use in impregnating the entire peripheral edge region 22A of the air electrode collector 22 is the same thermoplastic resin as the laminate films 26 and 27 which are used as resin films. The resin films are made of thermoplastic resin and have a window frame shape with a central area opening 24 educated. The opening 24 of the laminate film 26 forms an air inlet 28 the cathode 11 ,

The aluminum laminate films 26 and 27 include a heat-resistant thermoplastic resin base material layer such as polyethylene terephthalate (PET), and a thermoplastic resin adhesive layer such as polypropylene (PP), polyethylene (PE) and ethylene vinyl acetate (EVA).

In the laminate layer 26 the base material layer is on the upper side, the adhesive layer is on the lower side. In the laminate film 27 the adhesive layer is on the top, the base layer on the bottom.

The cathode is made 11 using the laminate films 26 and 27 in the following way:
Contacting step: first, the end area 21A of the cathode connection 21 For example, with a front side of the air electrode collector 22 brought into contact.
Insertion step: next becomes the peripheral edge area 22A of the air electrode collector 22 as well as the end area 21A of the cathode connection 21 between the laminate films 26 and 27 inserted from the vertical direction and clamped.
Heat-welding and impregnating step: subsequently the air-electrode collector 22 and the end area 21A of the cathode connection 21 by heat welding the laminate films 26 and 27 integrated with each other using, for example, a hot press, and the entire peripheral edge area 22A of the air electrode collector 22 becomes with the thermoplastic resin of the laminate films 26 and 27 forming the impregnation zone 23 impregnated. The hot-pressing in the heat-welding and impregnating step is carried out under the following conditions: in the case where the adhesive layers of the laminate films 26 and 27 made of PP, there is the heating temperature 160 to 180 ° C, and the welding pressure is 20 kgf / cm ² (for 30 seconds). If the adhesive layers of the laminate films 26 and 27 made of EVA, the heating temperature is 140 to 160 ° C at a welding pressure of 20 kgf / cm ² (30 seconds).

As in 1 is shown, there is the electrolyte 13 between the cathode 11 having the structure described above and the composite anode having the structure also described above.

The adhesive layers in the laminate film 26 the cathode 11 and in the aluminum laminate film 19 the composite anode are connected together. The result is the lithium-air battery 10 finished with a laminated cell structure in which the cathode 11 , the composite anode 12 and the electrolyte 13 as a unit.

• (1) Da der Luft-Elektrodenkollektor 22 und der Endbereich 21A des Kathodenanschlusses 21 integriert durch den Wärmeschweißprozess gemäß 2 ausgebildet werden, wird die Klebekraft zwischen dem Luft-Elektrodenkollektor 22 und dem Kathodenanschluss 21 verstärkt, was wiederum die elektrische Leitfähigkeit des Lithium-Luft-Akkumulators 10 verbessert. Da es nicht notwendig ist, das metallische Maschengebilde 109 (8) an dem Luft-Elektrodenkollektor 22 vorzusehen, lässt sich daher eine Gewichtsreduzierung und auch eine Verringerung der Dicke des Lithium-Luft-Akkumulators 10 erreichen.
• (2) Da der gesamte Umfangsrandbereich 22A des Luft-Elektrodenkollektors 22 mit dem thermoplastischen Harz imprägniert ist, welches die Laminatfilme 26 und 27 bildet, befindet sich die Imprägnierzone 23 an dem gesamten Umfangsrandbereich 22A des Luft-Elektrodenkollektors 22, wie in 3 gezeigt ist. Im Ergebnis kann der Umfangsrandbereich 22A des Luft-Elektrodenkollektors 22 eine fluiddichte Struktur darstellen, wodurch es möglich ist, ein Lecken des Elektrolyts 13 aus dem Umfangsrandbereich 22A und dessen Nahbereich zu unterbinden. Folglich lässt sich die Kathode 11 als Superstruktur einer laminierten Lithium-Luft-Akkumulatorzelle ausbilden, und man kann mehrere Lithium-Luft-Akkumulatoren 10 unter Verwendung der Kathode 11 schichten.
• (3) Der Endbereich 21A des Kathodenanschlusses 21 ist mit thermoplastischem Harz beschichtet aufgrund der Wärmeverschweißung des Kathodenanschlusses 21 und des Luft-Elektrodenkollektors 22 mit dem thermoplastischen Harz, wie in 3 gezeigt ist. Im Ergebnis kann eine gegenseitige Berührung des Kathodenanschlusses 21 und des Elektrolyts 13 verhindert werden, wodurch es möglich ist, eine Korrosion des Kathodenanschlusses 21 zu unterdrücken, die verursacht würde durch den Elektrolyt 13, der aufgrund des durch die Zellenreaktion entstehenden Lithiumhydroxids stark alkalisch wird. Es ist also möglich, eine Zunahme des elektrischen Widerstands des Luft-Elektrodenkollektors zu unterbinden, die verursacht wird durch das Haften von Korrosionsprodukten an dem Luft-Elektrodenkollektor 22. Diese Korrosionsprodukte werden hervorgerufen durch Korrosion von Aluminium oder Nickel, welches Bestandteil des Kathodenanschlusses 21 ist. Dies wiederum macht es möglich, eine effektive Fläche zu verkleinern, die notwendig ist für eine Reaktion innerhalb des Lithium-Luft-Akkumulators 10. Die Beeinträchtigung der Eigenschaften des Lithium-Luft-Akkumulators 10, namentlich der Akkumulator-Kapazität und der Ausgangsleistung sowie Lebensdauer werden unterdrückt.
• (4) Da die Korrosion des Kathodenanschlusses 21 durch den Elektrolyten 13 in der oben geschilderten Weise unterdrückt wird, ist es nicht notwendig, teures Platin als Werkstoff für den Kathodenanschluss 21 einzusetzen. Da Aluminium oder Nickel stattdessen verwendet werden kann, lassen sich die Kosten des Kathodenanschlusses 21 verringern.
• (5) Wie in 2 zu sehen ist, ist der gesamte Umfangsrandbereich 22A des Luft-Elektrodenkollektors 22 mit dem thermoplastischen Harz imprägniert, welches die Laminatfilme 26 und 27 zur Bildung der Imprägnierzone 23 darstellt. Im Ergebnis wird der Umfangsrandbereich 22A des Luft-Elektrodenkollektors 22 verstärkt, seine Steifigkeit wird erhöht. Aus diesem Grund lässt sich die mit dem Luft-Elektrodenkollektor 22 ausgestattete Kathode 11 in einfacher Weise ausgerichtet mit anderen Elementen wie zum Beispiel der Verbundanode 12 positionieren, so dass eine hinreichende Positioniergenauigkeit und Montagefreundlichkeit der Kathode 11 erzielt werden kann. Im Ergebnis lässt sich die Fertigung des Lithium-Luft-Akkumulators 10 verbessern, während eine Verringerung der Ausbeute des Lithium-Luft-Akkumulators 10 vermieden werden kann. Hierdurch lässt sich das Schichten oder Laminieren mehrerer Lithium-Luft-Akkumulatoren 10 in einfacher Weise bewerkstelligen.

Because of this, the cathode achieves 11 of the lithium-air battery 10 In the first embodiment, the following advantageous modes of action (1) to (5):

• (1) Since the air-electrode collector 22 and the end area 21A of the cathode connection 21 integrated by the heat welding process according to 2 are formed, the adhesive force between the air electrode collector 22 and the cathode terminal 21 amplified, which in turn increases the electrical conductivity of the lithium-air battery 10 improved. Since it is not necessary, the metallic mesh 109 ( 8th ) on the air electrode collector 22 Provide, therefore, can be a weight reduction and also a reduction in the thickness of the lithium-air battery 10 to reach.
• (2) Because the entire peripheral edge area 22A of the air electrode collector 22 impregnated with the thermoplastic resin containing the laminate films 26 and 27 forms, is the impregnation zone 23 at the entire peripheral edge area 22A of the air electrode collector 22 , as in 3 is shown. As a result, the peripheral edge portion 22A of the air electrode collector 22 represent a fluid-tight structure, whereby it is possible to lick the electrolyte 13 from the peripheral edge area 22A and to prevent its proximity. Consequently, the cathode can be 11 form a superstructure of a laminated lithium-air battery cell, and you can use several lithium-air batteries 10 using the cathode 11 layers.
• (3) The end area 21A of the cathode connection 21 is coated with thermoplastic resin due to the heat bonding of the cathode terminal 21 and the air-electrode collector 22 with the thermoplastic resin, as in 3 is shown. As a result, mutual contact of the cathode terminal 21 and the electrolyte 13 be prevented, whereby it is possible, a corrosion of the cathode terminal 21 to suppress that would be caused by the electrolyte 13 , which becomes highly alkaline due to the lithium hydroxide produced by the cell reaction. It is thus possible to suppress an increase in the electrical resistance of the air-electrode collector caused by the adhesion of corrosion products to the air-electrode collector 22 , These corrosion products are caused by corrosion of aluminum or nickel, which is part of the cathode connection 21 is. This, in turn, makes it possible to reduce an effective area necessary for a reaction within the lithium-air secondary battery 10 , The impairment of the properties of the lithium-air battery 10 , namely the accumulator capacity and the output power and life are suppressed.
• (4) Since the corrosion of the cathode terminal 21 through the electrolyte 13 is suppressed in the above-described manner, it is not necessary expensive platinum as a material for the cathode connection 21 use. Since aluminum or nickel can be used instead, the cost of the cathode connection can be eliminated 21 reduce.
• (5) As in 2 can be seen, is the entire peripheral edge area 22A of the air electrode collector 22 impregnated with the thermoplastic resin containing the laminate films 26 and 27 for the formation of the impregnation zone 23 represents. As a result, the peripheral edge area becomes 22A of the air electrode collector 22 reinforced, its rigidity is increased. Because of this, it can be used with the air-electrode collector 22 equipped cathode 11 easily aligned with other elements such as the composite anode 12 position so that sufficient positioning accuracy and ease of installation the cathode 11 can be achieved. The result is the manufacture of the lithium-air battery 10 improve while reducing the yield of the lithium-air battery 10 can be avoided. This allows the layers or lamination of several lithium-air batteries 10 accomplish in a simple manner.

Second Embodiment (FIGS. 4 and 5)

4 FIG. 15 is a perspective view illustrating a cathode as shown in FIG 2 wherein the cathode is formed by applying a second embodiment of the cathode structure of a lithium-air secondary battery according to the invention.

In the second embodiment, components or elements identical to those of the first embodiment are given the same reference numerals to simplify or eliminate the description.

A cathode 30 in the lithium-air battery 10 The second embodiment is different from the cathode 11 the first embodiment in that a cathode terminal 31 made of the same material as the air electrode collector 22 and integrally formed therewith, further characterized in that thermoplastic resin at least on one surface (back of the cathode terminal 31 in this second embodiment according to 5 (B) ) of the cathode terminal 31 is welded. In 5 (B) denotes reference numeral 32 a melted by thermoplastic resin zone on the back of the cathode terminal 31 ,

As in 5 (A) is an area of the side of the air-electrode collector 22 on the other surface of the cathode terminal 31 (a front of the cathode connection 31 this embodiment), in which the fused zone 32 is absent, coated with thermoplastic resin to cause a short circuit through the electrolyte 13 to prevent. A reference number 33 in 5 (A) denotes a zone of thermoplastic resin on the front of the cathode terminal 31 is covered.

In the cathode 30 is the entire peripheral edge area 22A of the air electrode collector 22 impregnated with thermoplastic resin as in the first embodiment. In 5 (A) and 5 (B) denotes a reference numeral 34 a zone covered with thermoplastic resin throughout the perimeter area 22A of the air electrode collector 22 impregnated. A broken (dashed) line 35 in the 5 (A) and 5 (B) shows an integrally formed shape of the cathode terminal 31 and the air-electrode collector 22 before the heat welding of and impregnation with the thermoplastic resin.

The thermoplastic resin material, which is the impregnated zone 34 in the peripheral edge area 22A of the air electrode collector 22 is a window frame shaped area 38 of laminated films 36 and 37 which serve as a resin film, as in 4 is shown. The thermoplastic resin which is the coated zone 33 on the front of the cathode connection 31 forms, forms a first tongue section 39 of the laminate film 36 , Furthermore, the thermoplastic resin forms the welded zone 32 on the back of the cathode connector 31 in the form of a second tongue area 40 of the laminate film 37 ,

The window frame shaped area 38 of the laminate film 36 is identical in shape to the laminate film 26 the first embodiment, while the window frame-shaped area 38 of the laminate film 37 identical in shape with the laminate film 27 the first embodiment. The laminate film 36 with the window frame-shaped area 38 and the first tongue area 39 is identical in material to the laminate film 26 the first embodiment, during the laminate film 37 with the window frame-shaped area 38 and the second tongue area 40 in the material is identical to the laminate film 27 the first embodiment.

The cathode 30 of the lithium-air battery 10 The second embodiment is manufactured in the following manner.

Preparation step: first, the sheet-like air-electrode collector 22 containing a carbon fiber in the form of, for example, a carbon cloth, and the cathode terminal 31 that integrates with the air-electrode collector 22 is formed, prepared. That is, it will be the air-electrode collector 22 and the cathode connection 31 prepared, which are integrally formed.

Insertion step: next becomes the peripheral edge area 22A of the air electrode collector 22 between the window frame area 38 of the laminate film 36 and the window frame area 38 of the laminate film 37 inserted from the vertical direction. At the insertion step, the first tongue area occurs 39 of the laminate film 36 in contact with an area on the side of the air-electrode collector 22 at the front of the cathode connector 31 while the second tongue area 40 of the laminate film 37 in contact with the entire back of the cathode terminal 31 occurs.

Impregnation step: then the entire peripheral edge area 22A of the air electrode collector 22 impregnated, for example, by a hot pressing with the thermoplastic resin of both window frame-shaped areas 38 the laminate films 36 and 37 is made to the impregnated zone 34 to obtain. In the course of the impregnation step becomes simultaneous with the impregnation of the peripheral edge area 22A of the air electrode collector 22 with the thermoplastic resin, the thermoplastic resin in the first tongue portion 39 of the laminate film 36 in an area of the side of the air-electrode collector 22 at the front of the cathode connector 31 for the formation of the coated zone 33 fused, and further, the thermoplastic resin in the second tongue area 40 of the laminate film 37 with the entire back of the cathode connector 31 fused to the melting zone 32 to build. The hot pressing in the course of the impregnating step is carried out under conditions substantially identical to those of the heat-fusion and impregnating step of the first embodiment.

• (6) Da der Kathodenanschluss 31 integriert mit dem flachstückähnlichen Luft-Elektrodenkollektor 22 geformt wird, der eine Kohlenstofffaser in Form beispielsweise eines Kohlenstofftuchs enthält, ist es nicht notwendig, das Haftvermögen zwischen dem Kathodenanschluss 31 und dem Luft-Elektrodenkollektor 22 zu berücksichtigen, so dass sich die Leitfähigkeit des Lithium-Luft-Akkumulators 10 zusätzlich steigern lässt.
• (7) Der Kathodenanschluss 31, der eine Kohlenstofffaser enthält, weist eine hohe Korrosionsbeständigkeit gegenüber hoher Alkalität des Elektrolyts 13 auf, verursacht durch Lithiumhydroxid und dergleichen, entstehend bei einer Zellenreaktion. Als Ergebnis wird die Korrosion des Kathodenanschlusses 31 zusätzlich verhindert.
• (8) In dem Kathodenanschluss 31, die eine Kohlenstofffaser enthält, lässt sich eine ausreichende Festigkeit des Anschlusses 31 erzielen, da das thermoplastische Harz auf die Rückseite des Anschlusses unter Bildung der Schmelzzone 32 aufgeschmolzen ist.

Because of this, the cathode can 30 of the lithium-air battery 10 of the second embodiment achieve the same advantageous effects (1) to (5) as in the first embodiment, in addition to the advantageous effects (6) to (8):

• (6) Since the cathode connection 31 integrated with the sheet-like air-electrode collector 22 With a carbon fiber in the form of, for example, a carbon cloth, it is not necessary to form the adhesion between the cathode terminal 31 and the air-electrode collector 22 to take into account, so that the conductivity of the lithium-air battery 10 additionally increase.
• (7) The cathode connection 31 containing a carbon fiber has a high corrosion resistance to high alkalinity of the electrolyte 13 caused by lithium hydroxide and the like arising in a cell reaction. As a result, the corrosion of the cathode terminal 31 additionally prevented.
• (8) In the cathode port 31 , which contains a carbon fiber, can be sufficient strength of the terminal 31 because the thermoplastic resin is on the back of the port to form the melt zone 32 is melted.

Third Embodiment (FIGS. 6 and 7)

6 Fig. 12 is a cross-sectional view illustrating a lithium-air secondary battery to which a third embodiment of the cathode structure of a lithium-air secondary battery according to the present invention is applied. In the third embodiment, components identical to those of the first embodiment are given the same reference numerals to simplify or eliminate the description.

A cathode 50 of the lithium-air battery 10 The third embodiment differs from that of the first embodiment in that a porous resin 51 with watertightness and ventilation characteristic outside the air-electrode collector 22 is located exposed to the outside via the air inlet 28 passing through the opening 24 of the laminate 26 is formed.

The porous resin 51 is porous polyethylene resin (PE) or fluorine-based porous resin. The porous resin 51 has one or both of the following configurations, one of which is the peripheral edge area 51A of the porous resin 51 on an outer surface of the laminate film 26 is fixed, as in 6 while the other configuration provides for the peripheral edge area 51A between the air-electrode collector 22 and the laminate film 26 is located as in 7 is shown.

If in the case of 6 the porous resin 51 porous PE resin, it is preferable, a placing step of placing porous resin of the peripheral edge portion 51A of the porous resin 51 on the outer surface of the laminate film 26 by heat fusion, following the hot-fusion and impregnation step of hot-welding the cathode terminal 21 at the peripheral edge area 22A of the air electrode collector 22 and impregnating the peripheral edge portion 22A with thermoplastic resin.

On the other hand, if the porous resin 51 is a porous fluorine-based resin, accordingly 6 Thus, it is preferable that the placing step for the porous resin by means of a primer, for example, a polyolefin-based primer, on the outer surface of the laminate film 26 then prepare the peripheral edge area 51A of the porous resin 51 on the outer surface of the laminate film 26 for example, with the aid of a cyanoacrylate adhesive after the heat-fusion and impregnation step is performed.

If in the case of 7 the porous resin 51 a porous PE resin, it is preferable, a porous resin placing step for fixing the peripheral edge portion 51A of the porous resin 51 between the laminate film 26 and the air-electrode collector 22 by hot-pressing and the like at the same time with the heat-fusion and impregnation step realized by hot-pressing.

If the porous resin 51 is a porous fluorine-based resin, according to the 7 For example, it is preferable to perform the porous resin placing step so that a large number of pores are formed in the peripheral edge portion 51A is formed and the peripheral edge area 51A of the porous resin 51 between the laminate film 26 and the air-electrode collector 22 is fixed by hot-pressing and the like, simultaneously with the heat-fusion and impregnation step, which is performed by hot-pressing and the like.

• (9) Da das poröse Harz 51, welches Wasserdichtigkeit und Belüftungseigenschaften aufweist, sich außerhalb des Luft-Elektrodenkollektors 22 befindet, der zur Außenseite hin über den Lufteinlass 28 exponiert ist, lässt sich eine Akkumulatorstruktur mit hoher Wasserabweisung realisieren. Dies macht es möglich, in zuverlässiger Weise zu verhindern, dass der Elektrolyt 13 durch Verdampfung beeinträchtigt wird.

Because of this, the cathode can 50 of the lithium-air battery 10 of the third embodiment achieve the same advantages (1) to (5) as in the first embodiment, in addition to the following advantageous effect (9):

• (9) Since the porous resin 51 , which has waterproofness and ventilation properties, outside the air-electrode collector 22 located to the outside via the air inlet 28 exposed, an accumulator structure can be realized with high water repellency. This makes it possible to reliably prevent the electrolyte 13 is affected by evaporation.

Furthermore, it should be noted that the present invention, as explained above with reference to various embodiments, is not limited thereto, but that numerous changes, modifications or variations are possible without departing from the scope defined by the claims.

Although the present embodiments are the aqueous electrolyte 13 can also use a non-aqueous electrolyte 13 in the structures of the cathodes 11 . 30 and 50 of the lithium-air battery 10 be used. Further, the porous resin 51 the third embodiment also outside the air-electrode collector 22 the cathode 30 of the lithium-air battery 10 of the second embodiment may be arranged simultaneously with or subsequent to the impregnating step.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2010-192313 [0004]

Cited non-patent literature

• Report by GS Yuasa Corporation "Present Status and Issues for Lithium / Air Battery Using Aqueous Electrolyte" (June 2010) [0004]

Claims (8)

Cathode structure of a lithium-air battery, comprising: a cathode terminal; and a sheet-like air-electrode collector containing a carbon fiber, wherein, in a state where the cathode terminal is in contact with the air electrode assembly, the air electrode collector and the cathode terminal are heat-sealed with a thermoplastic resin, and a peripheral edge portion of the air electrode collector is impregnated with a thermosetting resin. A cathode structure of a lithium-air secondary battery according to claim 1, wherein the cathode terminal is formed of a single substance of aluminum or nickel or an alloy thereof. Cathode structure of a lithium-air battery, comprising: a cathode terminal; and a sheet-like air-electrode collector containing a carbon fiber, wherein the cathode terminal is formed integrally with the air electrode collector, and a peripheral edge portion of the air electrode collector is impregnated with a thermoplastic resin. The cathode structure of a lithium-air secondary battery according to claim 3, wherein the thermoplastic resin is welded to at least one surface of the cathode terminal. A cathode structure of a lithium-air secondary battery according to any one of claims 1 to 3, wherein the peripheral edge portion of the air-electrode collector is impregnated with a thermoplastic resin forming a frame-shaped resin film having an opening and outside the air-electrode collector via the opening in the resin film, a porous resin having a waterproof property and a venting property is disposed. A method of fabricating a cathode of a lithium-air battery, comprising the steps of: Preparing a cathode terminal and a sheet-like air electrode collector containing a carbon fiber; Contacting the air-electrode collector with the cathode port; Inserting a peripheral edge portion of the air-electrode collector and the cathode terminal between a plurality of resin-molded frame films of thermoplastic resin, the frame-shaped resin films having an opening; and Heat-welding the air-electrode collector and the cathode terminal to the resin films, and impregnating the peripheral edge portion of the air-electrode collector with the thermoplastic resin. A method of fabricating a cathode of a lithium-air battery, comprising the steps of: Preparing a sheet-like air-electrode collector including a carbon fiber and a cathode terminal integrally molded with the air-electrode collector; Inserting a peripheral edge portion of the air-electrode collector between a plurality of thermoplastic resin frame-shaped resin films, the frame-shaped resin films having an opening; and Impregnating the peripheral edge portion of the air-electrode collector with the thermoplastic resin. A method of fabricating a cathode of a lithium-air secondary battery according to claim 6 or 7, further comprising a step of placing a porous resin having a waterproof property and venting property outside the air-electrode collector exposed over the opening of the resin films simultaneously with the or Following the heat-welding and the impregnating step, or the impregnating step.

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