Sheet for foldable battery, foldable battery, and method for manufacturing foldable battery

Abstract

This sheet for folding batteries is provided with: a sheet which has one surface and the other surface, while being provided with a plurality of intended fold lines that are parallel to each other; at least one electrolyte part which is arranged between a pair of intended fold lines on the sheet; and a plurality of electrode parts which are arranged adjacent to the electrolyte part, with the intended fold lines being sandwiched therebetween, on the sheet. The electrolyte part comprises: a through hole which is formed between the one surface and the other surface of the sheet; and electrolyte layers which are respectively formed on the surface and the other surface of the sheet so as to be opposite to each other, while being integrated with each other through the through hole.

Description

[Technical field]

[0001] The present invention relates to a sheet for a foldable battery, a foldable battery, and a method for manufacturing a foldable battery. This application claims priority based on Japanese Patent Application No. 2021-107684, filed on June 29, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] Stacked batteries are known as batteries used in various electronic devices. Stacked batteries have been attracting widespread attention in recent years because the battery voltage can be set to any voltage by changing the number of stacks, coupled with expectations for increased capacity.

[0003] Patent Document 1 discloses a stacked type all-solid-state secondary battery in which all-solid-state secondary batteries are connected in series.

[0004] Patent Document 2 discloses an electrode structure of a laminated battery, which comprises a negative electrode / separator compression body in which a strip-shaped negative electrode body is compressed between a pair of separators that are continuous in a strip shape, and a positive electrode connected body in which a plurality of positive electrodes are connected to each other by a strip-shaped positive electrode lead. In the laminated battery described in Patent Document 2, the negative electrode / separator compression body has folds between adjacent negative electrodes, which are alternately formed with mountain folds and valley folds. One positive electrode connected body has a structure in which adjacent positive electrodes are alternately inserted into one side and the other side of the negative electrode / separator compression body, and is assembled so as to face the negative electrode on which the negative electrode lead is formed via the separator, and is folded together with the negative electrode / separator compression body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 4-65071 [Patent Document 2] Japanese Patent Application Publication No. 2013-222602 [Non-patent literature]

[0006] [Non-Patent Document 1] Thomas BH Schroeder, Anirvan Guha, Aaron Lamoureux, Gloria VanRenterghem, David Sept, Max Shtein, Jerry Yang, and Michael Mayer, NATURE Volume552 (14 December 2017) p214-218. Summary of the Invention [Problem to be solved by the invention]

[0007] Various stacked type batteries have been studied so far, as shown in Patent Documents 1 and 2. However, in recent years, there has been a demand for further miniaturization and higher capacity batteries.

[0008] In addition, although Non-Patent Document 1 discloses a foldable concentration battery, the potential per cell is about 150 mV, and the current obtained is low at about several μA. Therefore, the battery performance of the foldable concentration battery described in Non-Patent Document 1 is insufficient for mounting in various electronic devices. In addition, the concentration battery described in Non-Patent Document 1 requires a difference in concentration between adjacent electrolytes sandwiching the electrodes, so the manufacturing process is complicated and the number of steps is increased. Furthermore, since a difference in concentration must be created between the electrolytes as described above, the battery inevitably becomes larger in size.

[0009] Among various types of batteries, metal-air batteries are known as relatively small (lightweight) batteries. Metal-air batteries have begun to attract attention in recent years due to their small size and high capacity, and their application as disaster and emergency batteries in particular has been considered.

[0010] However, metal-air batteries have a problem in that the contact between the electrolyte and the metal electrode (negative electrode) among the components leads to the deterioration of the metal electrode. In other words, even if a metal-air battery is simply a stacked type, while it can obtain a high capacity, it has a problem in that the battery performance is reduced due to the above-mentioned deterioration of the metal electrode.

[0011] In addition, when it is assumed that a battery will be used in a disaster or emergency, it is desirable to be able to store the battery for a long period of time without deterioration of the battery performance. However, in the case of a metal-air battery, long-term storage leads to deterioration of the battery performance over time due to the deterioration of the metal electrodes mentioned above. Therefore, it has been very difficult to store a metal-air battery for a long period of time without deterioration of the battery performance.

[0012] In view of the above, an object of the present invention is to provide a sheet for a foldable battery that can be stored for a long period of time without deteriorating battery performance and that can easily produce a compact foldable battery. Another object of the present invention is to provide a foldable battery made of such a sheet for a foldable battery, and a method for producing the foldable battery. [Means for solving the problem]

[0013] The present inventors have studied a method for suppressing the deterioration of battery performance that occurs when a battery is stored for a long period of time. As a result, they have found that by properly arranging the components of a battery on a sheet in advance, and then folding the sheet to form a battery at the stage of starting to use the battery, it is possible to prevent the deterioration of battery performance over time until just before starting to use the battery. Furthermore, by properly arranging the components of the battery on the sheet in a predetermined arrangement pattern, it is possible to achieve a multi-layer series connection, and as a result, it is possible to obtain a high-voltage battery.

[0014] The present invention has been made based on the above findings, and the gist of the present invention is as follows. [1] A foldable battery sheet according to one embodiment of the present invention comprises a sheet having one side and another side, and a plurality of parallel planned folding lines; At least one electrolyte portion disposed on the sheet between a pair of the intended folding lines; a plurality of electrode units disposed on the sheet adjacent to the electrolyte unit across the planned folding line; The electrolyte portion is A through hole provided between one surface and the other surface of the sheet; and an electrolyte layer formed on one surface and the other surface of the sheet so as to face each other across the through hole and integrated through the through hole. death, The electrode portion is A positive electrode layer provided on one surface of the sheet; a negative electrode layer provided on the other surface of the sheet at a position facing the positive electrode layer with the sheet therebetween; A conductor that penetrates the sheet and electrically connects the positive electrode layer and the negative electrode layer. do. [2] In the foldable battery sheet described in [1] above, the electrolyte parts may be arranged in a staggered pattern when the sheet is viewed in plan. 。 [ 3 ]the above[ 1 In the foldable battery sheet described in [1], the positive electrode layer may be arranged so as to be in contact with the electrolyte layer on one surface side of the sheet when the sheet is folded along the intended folding line. [ 4 ]the above[ 1 ]or[ 3 In the foldable battery sheet described in [1], the negative electrode layer may be arranged so as to be in contact with the electrolyte layer on the other surface side of the sheet when the sheet is folded along the intended folding line. [ 5 ]Above [1]~[ 4 In the foldable battery sheet according to any one of the above items [1] to [4], the electrolyte layer may be in a gel or solid state. [ 6 ]Above [1]~[ 5 In the foldable sheet for a battery according to any one of the above items [1] to [4], the sheet may be made of a hydrophobic sheet. [ 7 ]Above [1]~[ 6In the foldable sheet for a battery according to any one of the above items [1] to [4], a separator may be embedded in the through-holes.

[0015] [ 8 The foldable battery according to one embodiment of the present invention comprises the above-mentioned [1] to [ 7

[0023] The foldable battery sheet according to any one of claims 1 to 7,

[0016] [ 9 A method for producing a foldable battery according to one embodiment of the present invention comprises the steps of: 7

[0023] A method for producing a foldable battery comprising the sheet for foldable batteries according to any one of the preceding claims, A plurality of parallel planned folding lines are set on the sheet having one surface and another surface; When folding the sheet along the intended folding line, The sheet is folded so that the positive electrode layer is in contact with the electrolyte layer on one side thereof, and the negative electrode layer is in contact with the electrolyte layer on the other side thereof.

[0017] [ 10 A foldable battery sheet according to another embodiment of the present invention includes a sheet for an electrode part having one surface and another surface, and a plurality of parallel planned folding lines for the electrode part; A sheet for an electrolyte portion having one surface and another surface, and a plurality of parallel planned folding lines for the electrolyte portion set thereon; On one surface of the electrolyte portion sheet, Electrolyte section A plurality of electrolyte portions disposed on both sides of the intended folding line; A plurality of electrode portions are disposed on one surface and the other surface of the sheet for electrode portions between the planned folding lines for the electrode portions, The electrolyte portion is an electrolyte layer formed on one surface of the electrolyte portion sheet and integrated along the electrolyte portion folding line; death, The electrode portion is A plurality of positive electrode layers and a plurality of negative electrode layers provided in a lattice pattern on both sides of the electrode portion sheet; a conductor penetrating the electrode portion sheet to electrically connect the positive electrode layer and the negative electrode layer, The plurality of positive electrode layers are arranged along the planned folding line for the electrode portion, The plurality of negative electrode layers are arranged adjacent to a row of the plurality of positive electrode layers across the planned folding line for the electrode portion, The positive electrode layer and the negative electrode layer are provided so as to be positioned opposite to each other with the electrode portion sheet interposed therebetween.

[0018] [ 11 ] Another embodiment of the foldable battery of the present invention is the above [ 10

[0023] The present invention is directed to a foldable battery sheet.

[0019] [ 12 ] A method for producing a folding battery according to another embodiment of the present invention comprises the steps of: 10 A method for producing a foldable battery comprising the foldable battery sheet according to the present invention, The above The positive electrode layer and the negative electrode layer The electrolyte sheet is placed on both sides of the electrode sheet so that the electrolyte is in contact with the electrode sheet. The positive electrode layer and the negative electrode layer However, the sheets are folded along the planned folding lines for the electrode portion and the planned folding lines for the electrolyte portion so that the sheets face each other with the electrolyte portion on the sheet for the electrolyte portion interposed therebetween. Effect of the Invention

[0020] According to the above-described embodiment of the present invention, it is possible to provide a sheet for a foldable battery that can be stored for a long period of time without deteriorating battery performance and that enables a compact foldable battery to be easily manufactured. Furthermore, according to the above-described embodiment of the present invention, it is possible to provide a foldable battery made of such a sheet for a foldable battery and a method for manufacturing the foldable battery. [Brief description of the drawings]

[0021] [Figure 1A] FIG. 1A is a perspective view of one surface of a foldable battery sheet according to the present embodiment. [Figure 1B] FIG. 1B is a perspective view of the foldable battery sheet according to this embodiment, seen from the other side. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line XX shown in FIG. 1A. [Diagram 3]FIG. 3 is a schematic diagram of the foldable battery 1 according to this embodiment. [Figure 4A] Fig. 4A(a) is a perspective view of an electrode sheet constituting a foldable battery sheet according to a modified embodiment of the present invention, as viewed from one side. Fig. 4A(b) is a perspective view of an electrode sheet constituting a foldable battery sheet according to the present embodiment, as viewed from the other side. [Figure 4B] Fig. 4B(a) is a perspective view of an electrolyte sheet constituting a foldable battery sheet according to a modification of the present embodiment, as viewed from one side. Fig. 4B(b) is a perspective view of an electrolyte sheet constituting a foldable battery sheet according to the present embodiment, as viewed from the other side. [Figure 4C] Fig. 4C(a) is a schematic diagram showing an example of the overlapping arrangement of an electrode sheet and an electrolyte sheet constituting a foldable battery sheet according to a modification of this embodiment, and Fig. 4C(b) is a schematic diagram of a foldable battery 1A according to a modification of this embodiment. [Figure 5A] FIG. 5A is a graph showing the total voltage of each stack in an example. [Figure 5B] FIG. 5B is a graph showing the average voltage per cell (total voltage / number of cells) in each stack in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a foldable battery sheet, a foldable battery, and a method for manufacturing a foldable battery according to the present embodiment will be described with reference to the drawings. In addition, the drawings used in the following description may show characteristic parts in an enlarged scale for convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not be the same as in reality. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present embodiment is not necessarily limited to them, and can be appropriately modified and implemented within the scope that does not change the gist of the present embodiment.

[0023] [Foldable battery sheet] Fig. 1A is a perspective view of a foldable battery sheet according to the present embodiment, seen from one side. Fig. 1B is a perspective view of the foldable battery sheet according to the present embodiment, seen from the other side. Fig. 2 is a schematic cross-sectional view taken along line XX shown in Fig. 1A.

[0024] As shown in Figs. 1A and 1B, the foldable battery sheet 10 of this embodiment has a sheet 11, a plurality of electrolyte units 12 arranged on the sheet 11, and a plurality of electrode units 13 arranged on the sheet 11. Although Figs. 1A and 1B show an example in which a plurality of electrolyte units 12 are provided, this is not limited to this in this embodiment, and the electrolyte unit 12 may be one. That is, two electrode units 13 and one electrolyte unit 12 may be sufficient to function as a battery. Hereinafter, for convenience of explanation, a case in which a plurality of electrolyte units 12 are provided on the sheet 11 will be described.

[0025] The sheet 11 is a hydrophobic sheet. Specifically, the sheet 11 may be a film-like sheet made of an insulating material, and the material is not particularly limited. For example, polyethylene terephthalate, polypropylene, polyvinyl chloride, etc. may be used as the sheet 11. Since the electrolyte section 12 and the electrode section 13 described later are disposed on the sheet 11, it is preferable to adopt polyethylene terephthalate as the material of the sheet 11 from the viewpoint of durability.

[0026] Furthermore, when the foldable battery sheet 10 is applied to various batteries, the material of the sheet 11 may be appropriately determined according to the characteristics required for the battery to be applied. For example, when the foldable battery sheet 10 is applied to a metal-air battery, the battery performance can be further improved by using a breathable paper sheet as the sheet 11.

[0027] As shown in Figs. 1A and 1B, the sheet 11 has one surface 11a and the other surface 11b, and furthermore, a plurality of planned folding lines L parallel to each other are set on the sheet 11. As will be described later, when a battery is manufactured using the foldable battery sheet 10, the battery can be formed by folding along the planned folding lines L. Therefore, the planned folding lines L on the sheet 11 are set so that the adjacent electrolyte sections 12 and electrode sections 13 come into contact with each other when the sheet 11 is folded. Specifically, the planned folding lines L are arranged so that mountain folds and valley folds appear alternately when the sheet 11 is folded along the plurality of planned folding lines L.

[0028] The thickness of the sheet 11 is not particularly limited, and as described above, it is sufficient that the sheet 11 can be folded when manufacturing a battery. The thickness may be appropriately designed according to the material used for the sheet 11. The thicker the sheet 11, the larger the area of ​​the metal powder and catalyst in the electrode part 13 that contribute to the reaction, and as a result, a larger current value can be obtained. On the other hand, the thinner the sheet 11, the smaller the current value obtained. Therefore, from the viewpoint of ensuring a large current value, it is preferable to make the sheet 11 thicker. However, if the thickness of the sheet 11 is excessively large, the battery becomes bulky when the foldable battery sheet 10 is folded. In addition, if the thickness of the sheet 11 is excessively large, it becomes difficult to fold the positive electrode layer 13A and the negative electrode layer 13B so that they overlap with each other via the electrolyte layer 12a, which may cause poor contact between the elements on the sheet. In addition, the thicker the sheet 11, the higher the internal resistance of the battery, which may cause a decrease in output. From the above viewpoint, the thickness of the sheet 11 may be set to, for example, 100 μm to 1000 μm.

[0029] A plurality of electrolyte parts 12 are arranged on the sheet 11 between a pair of planned folding lines L. As shown in Figs. 1A and 1B, the rows of electrolyte parts 12 facing each other across the planned folding lines L are arranged so that the electrolyte parts 12 do not overlap each other when the foldable battery sheet 10 is folded. For example, the plurality of electrolyte parts 12 may be arranged in a staggered manner when the foldable battery sheet 10 is viewed in plan. In other words, the plurality of electrolyte parts 12 on the sheet are arranged with the planned folding lines L as axes so that the electrolyte parts 12 are not adjacent to each other.

[0030] As shown in FIG. 2, the electrolyte portion 12 includes a through hole H provided between one surface 11a and the other surface 11b of the sheet 11, and an electrolyte layer 12a formed on the one surface 11a and the other surface 11b of the sheet 11 so as to face each other across the through hole H.

[0031] The electrolyte layer 12a on one surface 11a of the sheet 11 and the electrolyte layer 12a on the other surface 11b are integrated via a through hole H. This through hole H is an element responsible for ion conduction when the foldable battery sheet 10 is folded to form a battery. The number of through holes H may be one per electrolyte section 12 as shown in FIG. 2, but may be appropriately determined depending on the shapes and dimensions of the sheet 11, the electrolyte section 12, etc., and a plurality of through holes H may be provided per electrolyte section 12.

[0032] The electrolyte layer 12a is desirably in a gel or solid state. The foldable battery sheet 10 according to this embodiment can be folded to form a battery. However, it is preferable that the foldable battery sheet 10 can be stored in a state where the elements (electrolyte portion 12 and electrode portion 13) on the sheet 11 are prevented from contacting each other before being formed into a battery. For this purpose, it is effective to suppress excessive deformation of the electrolyte layer 12a and leakage to other elements. Therefore, in this embodiment, it is preferable that the electrolyte layer 12a is in a gel or solid state in order to suppress excessive deformation of the electrolyte portion 12a and leakage to other elements.

[0033] In order to make the electrolyte layer 12a gelled or solid, it is preferable to add, for example, a gelling agent, a thickening agent, etc. to the material of the electrolyte layer 12a described later. Examples of gelling agents include gelatin, agarose, acrylamide, poly(ethylene glycol) diacrylate, and poly(ethylene glycol) dimethacrylate. Among these, it is preferable to use poly(ethylene glycol) diacrylate or poly(ethylene glycol) dimethacrylate because they are resistant to alkali and can be easily gelled by light irradiation. However, if the chain length of poly(ethylene glycol) diacrylate or poly(ethylene glycol) dimethacrylate is too short (for example, polymerization degree 1 to 3), it will solidify. Therefore, when using poly(ethylene glycol) diacrylate or poly(ethylene glycol) dimethacrylate, it is preferable to use one having a certain length or more (for example, polymerization degree 5 or more) in order to form a soft gel state. When poly(ethylene glycol) diacrylate or poly(ethylene glycol) dimethacrylate is used as a gelling agent, it is preferable to mix an acrylic monomer with a radical initiator and promote gelation by heating, light, etc. Alternatively, gelatin alone may be used as the electrolyte layer 12a.

[0034] As the material of the electrolyte layer 12a, for example, an aqueous electrolyte solution can be used. For example, the aqueous electrolyte solution can be an alkaline aqueous solution such as an aqueous potassium hydroxide solution or an aqueous sodium hydroxide solution, a neutral aqueous solution such as an aqueous potassium chloride solution or an aqueous sodium chloride solution, or an acidic aqueous solution such as an aqueous sulfuric acid solution. The total ion concentration of the aqueous electrolyte solution is sufficient to be 1 mmol / L or more, and more preferably 100 mmol / L or more. When the foldable battery sheet 10 of this embodiment is applied to a metal-air battery, it is particularly preferable to use an alkaline aqueous solution among these, from the viewpoint of increasing the output of the metal-air battery. The material of the electrolyte layer 12a may be one type alone, or two or more types may be used in combination. The electrolyte layer 12a is not limited to these examples, and may be, for example, an inorganic electrolyte.

[0035] The thickness of the electrolyte layer 12a is not particularly limited, but is preferably 0.1 mm or more because an excessively small thickness may lead to a decrease in battery performance, particularly capacity. On the other hand, an excessively large thickness may make it difficult to fold the foldable battery sheet 10 with good accuracy. From the viewpoint of compactifying the battery, it is preferable that the thickness of the electrolyte layer 12a is small. For example, the thickness of the electrolyte layer 12a is preferably 3 mm or less.

[0036] Furthermore, a separator may be embedded in the through-hole H of the electrolyte section 12. As described above, the through-holes H of the electrolyte section 12 are elements responsible for ion conduction when the foldable battery sheet 10 is folded to form a battery. However, if the electrode sections 13 (positive electrode layer 13A and negative electrode layer 13B) arranged on both sides of the electrolyte section 12 are too close to each other after folding, an electrical short circuit may occur. From this viewpoint, it is desirable to embed a separator in the through-holes H. By embedding a separator in the through-holes H, the positive electrode layer 13A and the negative electrode layer 13B described below are isolated, the electrolyte section 12 is supported, and sufficient ion conductivity between the positive electrode layer 13A and the negative electrode layer 13B can be ensured.

[0037] Examples of the material of the separator include porous polyethylene, porous polypropylene, nonwoven fabric, polyamide fiber, and the like, but the separator is not limited to these examples.

[0038] The electrode section 13 is disposed next to the electrolyte section 12 across the planned folding line L. This allows the electrolyte section 12 and the electrode section 13 to overlap when the foldable battery sheet 10 is folded along the planned folding line L, thereby forming a battery.

[0039] As shown in Figures 1A, 1B, and 2, the electrode portion 13 includes a positive electrode layer 13A provided on one surface 11a of the sheet 11, a negative electrode layer 13B provided on the other surface 11b of the sheet 11 at a position facing the positive electrode layer 13A with the sheet 11 in between, and a conductor 14 that provides electrical conductivity between the positive electrode layer 13A and the negative electrode layer 13B.

[0040] The positive electrode layer 13A provided on the one surface 11a of the sheet 11 is disposed so as to contact the electrolyte layer 12a on the one surface 11a side of the sheet 11 when the sheet 11 is folded along the planned folding line L. That is, in a plan view from the one surface 11a side of the sheet 11, the positive electrode layer 13A and the electrolyte layer 12a are provided alternately in a lattice pattern on the one surface 11a of the sheet 11.

[0041] Furthermore, the negative electrode layer 13B provided on the other surface 11b of the sheet 11 is disposed so as to contact the electrolyte layer 12a on the other surface 11b side of the sheet 11 when the sheet 11 is folded along the intended folding line L. That is, in a plan view from the other surface 11b side of the sheet 11, the negative electrode layer 13B and the electrolyte layer 12a are provided alternately in a lattice pattern on the other surface 11b of the sheet 11.

[0042] The positive electrode layer 13A is an element that becomes a positive electrode when the foldable battery sheet 10 is made into a folded battery. Therefore, any material that is generally used as a positive electrode can be applied to the positive electrode layer 13A. For example, if the foldable battery sheet 10 is applied to a metal-air battery, the positive electrode layer 13A becomes an air electrode (oxygen electrode), and in this case, examples of the material for the positive electrode layer 13A include a platinum-supported carbon material (platinum-supported carbon), an iron phthalocyanine-supported carbon material, and a manganese oxide-supported carbon material that promotes a reduction reaction.

[0043] The negative electrode layer 13B is an element that becomes the negative electrode when the foldable battery sheet 10 is made into a folded battery. Therefore, any material commonly used as a negative electrode can be used as the negative electrode layer 13B. For example, if the foldable battery sheet 10 is used in a metal-air battery, the negative electrode layer 13B can be made of a metal such as zinc, manganese, or lithium, an alloy of these metals, or an oxide of these metals.

[0044] There are no particular limitations on the form of the positive electrode layer 13A and the negative electrode layer 13B. The positive electrode layer 13A and the negative electrode layer 13B may be formed by applying a paste of a positive electrode material or a negative electrode material onto the sheet 11, or by applying particles (metal particles) of the positive electrode material or the negative electrode material using an inkjet coating device or the like.

[0045] 2, a conductor 14 that electrically connects the positive electrode layer 13A and the negative electrode layer 13B is provided so as to penetrate the sheet 11. That is, the positive electrode layer 13A provided on one surface 11a of the sheet 11 and the negative electrode layer 13B formed on the other surface 11b are provided so as to overlap with each other via the conductor 14 provided on the sheet 11.

[0046] When the foldable battery sheet 10 is made into a folded battery, the conductor 14 is an element that provides electrical continuity between the positive electrode layer 13A and the negative electrode layer 13B that overlap with each other sandwiching the sheet 11, and also supports both of them. Thus, the conductor 14 may be any material that has electronic conductivity, and examples of the material include carbon, metal, and conductive polymer.

[0047] The form of the conductor 14 is not particularly limited, and may be appropriately determined depending on the materials of the conductor 14 and the sheet 11, and the forms and materials of the positive electrode layer 13A and the negative electrode layer 13B. For example, when carbon is used as the conductor 14, the form of the conductor 14 may be ink-like (carbon ink) or plate-like (carbon plate). When carbon ink is used as the conductor 14, the conductor 14 can be formed by, for example, applying the carbon ink to both sides of the sheet 11 so as to penetrate the sheet, and then drying the sheet. When a carbon plate is used as the conductor 14, the conductor 14 can be formed by, for example, arranging a carbon plate cut out in advance to a desired size so as to penetrate the sheet 11.

[0048] [Foldable battery] FIG. 3 shows a foldable battery 1 according to this embodiment. As shown in FIG. 3, the foldable battery 1 is made of the foldable battery sheet 10 described above, and can be obtained by folding the foldable battery sheet 10 along the planned folding lines L. 3 shows only one cell for ease of explanation, but in reality, a plurality of battery elements (electrolyte parts 12 and electrode parts 13) are arranged on the sheet 11. Therefore, by folding the foldable battery sheet 10 along the planned folding lines L, multiple cells can be connected in series.

[0049] [Manufacturing method of foldable battery] The foldable battery 1 according to this embodiment can be obtained by folding the sheet 11 along the intended folding lines L using the foldable battery sheet 10 described above so that the electrode sections 13 and the electrolyte section 12 are in contact with each other. Specifically, first, foldable battery sheet 10 is folded along planned folding line L so that mountain folds and valley folds alternate, and then sheet 11 is folded along the fold so that positive electrode layer 13A and negative electrode layer 13B overlap with electrolyte layer 12a interposed therebetween. That is, when folding sheet 11 along planned folding line L, positive electrode layer 13A is folded so as to contact electrolyte layer 12a on one surface 11a side of sheet 11, and negative electrode layer 13B is folded so as to contact electrolyte layer 12a on the other surface 11b side of sheet 11, thereby manufacturing a folded battery 1 as shown in FIG.

[0050] Furthermore, as a method of folding the foldable battery sheet 10, in addition to the so-called "accordion fold" as shown in Figs. 1A and 1B, for example, the so-called "Miura fold" can also be applied.

[0051] The difference between the accordion fold shown in FIG. 1A and the Miura fold is in the method of setting the intended folding lines. In the accordion folding of FIG. 1A, the planned folding lines L are set to be parallel to each other, and if the area surrounded by the planned folding lines L is one square, each square is a rectangle. On the other hand, in the case of Miura folding, the planned folding lines are zigzag lines, and each square is a parallelogram. Even when Miura folding is applied, the arrangement of the components of the electrolyte section and the electrode section may be the same as in FIG. 1A.

[0052] This type of Miura folding is a method that allows the battery to be folded simply by pressing the diagonal parts, making it easy to manufacture foldable batteries.

[0053] [Modification of the embodiment] In the above embodiment, the foldable battery 1 using one foldable battery sheet 10 has been described, but the present invention is not limited to this, and the foldable battery may use two or more foldable battery sheets.

[0054] FIG. 4A(a) is a perspective view of the electrode sheet 11A constituting the foldable battery sheet 10A according to the present embodiment, as viewed from one side. FIG. 4A(b) is a perspective view of the electrode sheet 11A constituting the foldable battery sheet 10A according to the present embodiment, as viewed from the other side. FIG. 4B(a) is a perspective view of the electrolyte sheet 11B constituting the foldable battery sheet 10A according to the present embodiment, as viewed from one side. FIG. 4B(b) is a perspective view of the electrolyte sheet 11B constituting the foldable battery sheet 10A according to the present embodiment, as viewed from the other side. FIG. 4C is a schematic cross-sectional view of the electrode sheet 11A and the electrolyte sheet 11B superimposed on each other. The same configurations and elements as those of the foldable battery sheet 10 of this embodiment shown in FIG. 1A are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0055] A foldable battery sheet 10A, which is a modified example of this embodiment, has an electrode portion sheet 11A having one side 11Aa and the other side 11Ab as shown in FIG. 4A, and a plurality of parallel planned folding lines M for the electrode portion set thereon, and an electrolyte portion sheet 11B having one side 11Ba and the other side 11Bb as shown in FIG. 4B, and a plurality of parallel planned folding lines N for the electrolyte portion set thereon.

[0056] The foldable battery sheet 10A also has a plurality of electrolyte parts 22 arranged on one surface 11Ba of the electrolyte part sheet 11B on both sides of the planned folding line N for the electrolyte part. The electrolyte parts 22 are formed on the one surface 11Ba of the electrolyte part sheet 11B, and have electrolyte layers 22a integrated on the planned folding line N for the electrolyte part. That is, the electrolyte parts 22 are provided so as to straddle the planned folding line N for the electrolyte part, and are integrated on the planned folding line N for the electrolyte part. As shown in FIG. 4B(b), the electrolyte parts 22 are not formed on the other surface 11Bb of the electrolyte part sheet 11B.

[0057] The specific material and form of the electrolyte layer 22a may be the same as those of the electrolyte layer 12a in the foldable battery sheet 10 of the present embodiment described above.

[0058] In this modification, the electrolyte portion 22 may have a through hole. In this case, the through hole may be provided between the one surface 11Ba and the other surface 11Bb of the electrolyte portion-forming sheet 11B. When a through hole is provided in this modification, the position of the through hole may be anywhere between the one surface 11Ba and the other surface 11Bb of the electrolyte portion-forming sheet 11B.

[0059] The foldable battery sheet 10A also has a plurality of electrode portions 13 arranged between the intended folding lines M for the electrode portions on one surface 11Aa and the other surface 11Ab of the electrode portion sheet 11A. The multiple electrode portions 13 have multiple positive electrode layers 13A and multiple negative electrode layers 13B arranged on both sides of the electrode portion sheet 11A in a lattice-like arrangement in a planar view, and a conductor 14 that penetrates the electrode portion sheet 11A to connect the positive electrode layers 13A and the negative electrode layers 13B.

[0060] 4A and 4B, the positive electrode layers 13A are arranged along the planned folding line M for the electrode portion. The negative electrode layers 13B are arranged adjacent to the row of the positive electrode layers 13A across the planned folding line M for the electrode portion. That is, the row of the positive electrode layers 13A and the row of the negative electrode layers 13B are arranged alternately in a direction perpendicular to the planned folding line M for the electrode portion (the left-right direction in FIG. 4A).

[0061] The positive electrode layer 13A and the negative electrode layer 13B are provided so as to be positioned opposite to each other with the electrode portion sheet 11A sandwiched between them. For example, the negative electrode layer 13B is provided on the opposite side (the other surface 11Ab side) of the positive electrode layer 13A on the one surface 11Aa side of the electrode portion sheet 11A. That is, the positive electrode layer 13A and the negative electrode layer 13B are provided as a pair with the electrode portion sheet 11A sandwiched between them.

[0062] Fig. 4C(a) shows an example of the overlapping arrangement of electrode sheet 11A and electrolyte sheet 11B constituting foldable battery sheet 10A, which is a modification of this embodiment, and Fig. 4C(b) shows a schematic diagram of foldable battery 1A, which is a modification of this embodiment. 4C(a) and (b), the folded battery 1A is composed of a foldable battery sheet 10A having the above-mentioned electrode portion sheet 11A and electrolyte portion sheet 11B. That is, the folded battery 1A can be obtained by overlapping at least one electrode portion sheet 11A and two or more electrolyte portion sheets 11B and folding them along the intended folding lines M and N. 4C(a) and (b) show only three cells for ease of explanation, but in reality, multiple battery elements are arranged on each sheet. Therefore, by overlapping the electrode portion sheet 11A and the electrolyte portion sheet 11B and folding them, a multi-layer series connection is realized.

[0063] 4C(a), in the folded battery 1A according to the modified embodiment of the present invention, first, electrolyte part sheets 11B are superimposed on both sides of electrode part sheet 11A so that electrode parts 13 and electrolyte parts 22 are in contact with each other. Next, each sheet is folded along the planned folding lines M for electrode parts and the planned folding lines N for electrolyte part so that adjacent electrode parts 13 (i.e., positive electrode layer 13A and negative electrode layer 13B) on electrode part sheet 11A face each other via the electrolyte part 22 on electrolyte part sheet 11B. In this manner, the folded battery 1A can be obtained.

[0064] The configurations of the foldable battery sheet 10 according to the present embodiment and the foldable battery sheet 10A, which is a modified example, have been described above. With these configurations, each element of the battery can be stored in a non-contact state. Therefore, long-term storage is possible without deterioration of the battery performance until just before use as a battery is started. In addition, with the foldable battery sheet 10 according to the present embodiment, each element of the battery is appropriately arranged on the sheet, so that a battery can be easily manufactured by simply folding the sheet when used as a battery. In addition, by appropriately arranging each battery element on the sheet, a multi-layer series connection can be achieved, and as a result, a high-voltage battery can be obtained. Furthermore, when a battery is formed using the foldable battery sheet 10 or foldable battery sheet 10A of this embodiment, one cell can be formed by stacking at least a pair of electrode parts and one electrolyte part, a total of three elements. Therefore, compared with conventional laminated batteries (e.g., concentration batteries that require five elements per cell), a compact battery with a smaller thickness per cell can be realized. Furthermore, according to this embodiment, there is no need to impart a concentration to the electrolyte, so that a foldable battery can be manufactured more simply.

[0065] Furthermore, by using the foldable battery sheet 10 according to this embodiment and the foldable battery sheet 10A, which is a modified example, a three-dimensional battery can be created from a sheet having a substantially planar structure. In other words, since the sheet can be stored until it is used as a battery, a reduction in storage space can also be expected.

[0066] The foldable battery sheet according to the present embodiment and its modified examples described above can be applied to various types of batteries. For example, the foldable battery sheet according to the present embodiment and its modified examples can be used for metal-air batteries, fuel cells, voltaic cells, metal-ion batteries (lithium-ion batteries, etc.), etc. In this case, the material of each battery element arranged on the sheet can be appropriately selected according to the type of battery.

[0067] In the above-described embodiment and its modified examples, the sheet 11 of the electrolyte portion 12 may not be provided with through-holes, and only a separator may be provided. EXAMPLES

[0068] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.

[0069] A 100 μm thick PET (polyethylene terephthalate) film was used as the sheet, and a foldable battery sheet was prepared by forming a conductor, an electrolyte part, an air electrode (positive electrode part), and a metal electrode (negative electrode part) in the arrangement pattern shown in Figures 1A and 1B. The interval between adjacent planned folding lines L was 10 mm.

[0070] The conductors were made by applying carbon ink to both sides of the sheet to a diameter of approximately 8 mm, and then drying by heating at 120°C for 1 hour to form multiple conductors. The carbon ink was applied to both sides of the sheet so as to sandwich the through-holes (φ2 mm) provided on the sheet.

[0071] In addition, a mixture (pH 13) of potassium hydroxide (concentration: 0.1 mol / L), gelling agent, and radical initiator was used and applied to a sheet to a diameter of approximately 8 mm to form an electrolyte part. Specifically, poly(ethylene glycol) dimethacrylate (number average molecular weight Mn: 750, polymerization degree: 17, manufactured by Sigma-Aldrich) was used as the gelling agent, and a mixture of the gelling agent and the aforementioned potassium hydroxide was prepared. Next, 1 vol% of a radical initiator (2-hydroxy-2-methylpropiophenone (manufactured by Sigma-Aldrich)) was added to the mixture of gelling agent and potassium hydroxide and mixed, and further, the mixture was irradiated with approximately 750 μW / cm using a 365 nm light irradiation device (SLUV-4, manufactured by AS ONE Corporation). 2 The electrolyte part was formed by curing the film by irradiating the film with light at a light intensity of 1000 .mu.m. In addition, a paste-like platinum-supported carbon material (platinum-supported carbon) and zinc particles were applied to a diameter of 8 mm, and then heated and dried at 120°C for 2 hours to form an air electrode and a metal electrode, respectively. The electrolyte, air electrode, and metal electrode all had a thickness in the range of 100 μm to 200 μm. Furthermore, through holes measuring φ2 mm were provided on the sheets in the conductor and electrolyte to ensure electrical conductivity and ionic conductivity.

[0072] The obtained foldable battery sheet was folded along the planned folding line L to produce a battery (metal-air battery) in which a total of three cells were connected in series. Each stack of the obtained batteries was evaluated.

[0073] Figure 6A shows the total voltage of each stack, and Figure 6B shows the average voltage (total voltage / number of cells) per cell in each stack. As shown in Figure 6A, the voltage increases as the number of cells (number of stacks) increases, and when the number of cells was three (three stacks), the total voltage was 3.17V. Also, as shown in Figure 6B, even when the number of cells increased, the voltage per cell remained almost constant. When the number of cells was three (three stacks), a current of 30μA was measured by connecting to a 680Ω resistor. [Explanation of symbols]

[0074] 1. Foldable battery 10, 10A…Foldable battery seat 11…Sheet 11A…Electrode sheet 11B…Electrolyte sheet 11a, 11Aa, 11Ba…One side 11b, 11Ab, 11Bb...other side 12, 22...Electrolyte part 12a, 22a...electrolyte layer 13...Electrode part 13A…Positive electrode layer 13B…Negative electrode layer 14...Conductor L: planned folding line M: Electrode part bending line N…Electrolyte part to be bent H...Through hole

Claims

1. A sheet having one surface and another surface, and a plurality of parallel folding lines set thereon; At least one electrolyte portion disposed on the sheet between a pair of the intended folding lines; a plurality of electrode units disposed on the sheet adjacent to the electrolyte unit across the planned folding line; The electrolyte portion is A through hole provided between one surface and the other surface of the sheet; an electrolyte layer formed on one surface and the other surface of the sheet so as to face each other across the through hole and integrated through the through hole; The electrode portion is A positive electrode layer provided on one surface of the sheet; a negative electrode layer provided on the other surface of the sheet at a position facing the positive electrode layer with the sheet therebetween; and a conductor penetrating the sheet to electrically connect the positive electrode layer and the negative electrode layer.

2. 2. The foldable battery sheet according to claim 1, wherein the electrolyte sections are arranged in a staggered pattern when the sheet is viewed from above.

3. 2. The foldable battery sheet according to claim 1, wherein the positive electrode layer is disposed so as to be in contact with the electrolyte layer on one surface side of the sheet when the sheet is folded along the intended folding line.

4. 4. The foldable battery sheet according to claim 1, wherein the negative electrode layer is disposed so as to be in contact with the electrolyte layer on the other surface side of the sheet when the sheet is folded along the intended folding line.

5. 5. The foldable sheet for a battery according to claim 1, wherein the electrolyte layer is in a gel or solid state.

6. 6. The foldable sheet for a battery according to claim 1, wherein the sheet is made of a hydrophobic sheet.

7. 7. The foldable sheet for a battery according to claim 1, wherein a separator is embedded in the through-holes.

8. A foldable battery comprising the sheet for foldable batteries according to any one of claims 1 to 7.

9. A method for producing a foldable battery comprising the sheet for foldable batteries according to any one of claims 1 to 7, comprising the steps of: A plurality of parallel planned folding lines are set on the sheet having one surface and another surface; When folding the sheet along the intended folding line, a sheet having a positive electrode layer and a negative electrode layer, the positive electrode layer being in contact with the electrolyte layer on one side of the sheet, and the negative electrode layer being in contact with the electrolyte layer on the other side of the sheet.

10. A sheet for an electrode portion having one surface and another surface, and a plurality of parallel planned folding lines for the electrode portion set thereon; A sheet for an electrolyte portion having one surface and another surface, and a plurality of parallel planned folding lines for the electrolyte portion set thereon; A plurality of electrolyte parts are arranged on one surface of the electrolyte part sheet on both sides of the electrolyte part folding line; A plurality of electrode portions are disposed on one surface and the other surface of the sheet for electrode portions between the planned folding lines for the electrode portions, The electrolyte portion is an electrolyte layer formed on one surface of the electrolyte portion sheet and integrated along the electrolyte portion folding line; The electrode portion is A plurality of positive electrode layers and a plurality of negative electrode layers provided in a lattice pattern on both sides of the electrode portion sheet; a conductor penetrating the electrode portion sheet to electrically connect the positive electrode layer and the negative electrode layer, The plurality of positive electrode layers are arranged along the planned folding line for the electrode portion, The plurality of negative electrode layers are arranged adjacent to a row of the plurality of positive electrode layers across the planned folding line for the electrode portion, A foldable sheet for a battery, characterized in that the positive electrode layer and the negative electrode layer are provided so as to be positioned opposite each other with the electrode portion sheet interposed therebetween.

11. A foldable battery comprising the sheet for foldable batteries according to claim 10.

12. A method for producing a foldable battery comprising the sheet for foldable batteries according to claim 10, comprising the steps of: the electrolyte portion sheet is superposed on both sides of the electrode portion sheet so that the electrolyte portion is in contact with the positive electrode layer and the negative electrode layer, respectively; and then folding each sheet along the planned folding lines for the electrode portions and the planned folding lines for the electrolyte portion so that adjacent positive electrode layers and negative electrode layers on the sheet for the electrode portions face each other via the electrolyte portion on the sheet for the electrolyte portion.

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