Flexible thermochemical battery and flexible thermochemical battery module

Abstract

To provide a thermal chemical battery with high versatility that can be applied in various places for various purposes, and a thermal chemical battery module.SOLUTION: A flexible thermal chemical battery includes a pair of electrodes 10 and an electrolyte solution 30 existing between the pair of electrodes in contact with the electrodes and generates power when temperature gradient exists between the pair of electrodes. The flexible thermal chemical battery includes a sealing body containing the electrolyte solution 30 inside and having flexibility. A flexible thermal chemical battery includes a pair of electrodes 10, a pair of electrolyte solutions existing between the pair of electrodes and separated by a separating material and includes a sealing body with flexibility even in a thermal chemical battery that generates power under a predetermined temperature condition. The sealing body of the thermal chemical battery may include the pair of electrodes 10 with flexibility and a case 20 disposed between end parts of the pair of electrodes, containing the electrolyte solution 30 internally, and having flexibility and insulating properties.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a thermochemical battery that can convert thermal energy into electrical energy (power generation) via chemical energy, and more particularly to a thermochemical battery that has been given flexibility. [Background technology]

[0002] Thermoelectrics convert thermal energy directly into electrical energy, and can generate electricity continuously if there is a heat source. On the other hand, batteries generate electrical energy using chemical reactions. Thermochemical batteries generate electricity through a chemical reaction that uses heat, so they have the advantage of being able to generate a higher voltage than thermoelectric conversion, which converts heat directly into electricity.

[0003] Specifically, some thermo-electrochemical cells generate electricity by utilizing a chemical reaction caused by thermal energy in the presence of a heat source (Non-Patent Documents 1 and 3). On the other hand, some thermo-electrochemical cells can be used as batteries by utilizing a chemical reaction caused by thermal energy and by alternately maintaining them in high-temperature and low-temperature locations (Non-Patent Documents 2 and 3). The former can generate electricity semi-permanently and continuously, while the latter can be used repeatedly by alternately maintaining them in a state with a heat source (high temperature) and a state without a heat source (low temperature).

[0004] Thermochemical batteries basically consist of two electrodes, a positive electrode and a negative electrode, and an aqueous electrolyte between them. They have two operating modes. One, as described in Non-Patent Documents 1 and 3, involves a temperature difference between the two electrodes. This difference in the rate of chemical reactions creates a carrier concentration difference in the electrolyte, generating a potential difference (hereafter referred to as a power generation type). The other, as described in Non-Patent Documents 2 and 3, involves a separator separating different types of electrolytes into upper and lower or left and right sections. When the entire system, including the electrodes, is heated, a potential difference is generated due to the difference in chemical reactions between the upper and lower (left and right) sides of the separator. At low temperatures, a reverse reaction occurs (current flow direction is reversed), generating a potential difference (hereafter referred to as a charging type). In either case, a surface reaction between ions and electrons is required on the electrode surface in contact with the electrolyte, necessitating the selection of an appropriate electrode.

[0005] For example, metals, particularly precious metals such as platinum, which have high catalytic activity, are often used for both electrodes of a thermochemical battery (Non-Patent Document 4). Also, some batteries use a carbonized film for one electrode and platinum for the other (Patent Document 1). Furthermore, the present inventors have invented a thermochemical battery that uses an organic conductive film electrode as the electrode, which has properties equal to or better than those of platinum, and this can be used as the power generation type or charging type thermochemical battery (Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Unexamined Patent Publication No. 8-171918 [Patent Document 2] Patent No. 6732227 [Non-patent literature]

[0007] [Non-Patent Document 1] “Seebeck coefficients in ionic liquids prospects for themo-electrochemical cells”, TJAbraham, DRMacFarlane and JMPringle, Chem. Commun., 47, (2011) pp.6260-6262. [Non-patent document 2] “Charging-free electrochemical system for harvesting low-grade thermal energy”, Y. ang, SWLee, H.Ghasemi, J.Loomis, X.Li, D.Kraemer, G.Zheng, Y.Cui and G.Chen, PNAS, 111 (48), (2014), pp.17011-17016. [Non-patent document 3] “Poly(3,4-Ethylene Dioxythiophene) / Poly(Styrene Sulfonate)Electrodes in Electrochemical Cells for Harvesting Waste Heat”, Y. Wang, M.Mukaida, K.Kirihara, L.Lyu, and Q.Wei, Energy Technology, (2019), pp.1900998(1 of 8)-1900998(8 of 8). [Non-patent document 4] “Review of Thermally Regenerative Electrochemical Systems”, HLChum and RAOsteryoung, Synopsis and Executive Summary, vol.1, Solar Energy Research Institute, (1980) pp.1-53. Summary of the Invention [Problem to be solved by the invention]

[0008] As such, thermochemical batteries are convenient and environmentally friendly because they do not require wiring for charging, can generate sufficient power continuously, and can be used repeatedly. Therefore, it is expected that the range of applications of thermochemical batteries will expand in the future, such as being able to be carried around and used in various places and being installed in mobile objects. On the other hand, thermochemical batteries contain an aqueous electrolyte inside, so they have a rigid structure to prevent leakage of the electrolyte, and they are not suitable for use on large, curved, or uneven surfaces, which limits their range of application.

[0009] Therefore, an object of the present invention is to provide a thermochemical battery and a thermochemical battery module that are highly versatile and can suppress electrolyte leakage in a thermochemical battery having an aqueous electrolyte, and that can be applied to a variety of locations and purposes. [Means for solving the problem]

[0010] In thermochemical batteries, in order to generate power from a low-temperature heat source, a battery that can be adapted to a wide surface so as to be compatible with a relatively wide range of heat sources is effective. However, because the electrolyte in a thermochemical battery is an aqueous solution, it has a rigid structure to prevent leakage. However, according to the present invention, the sealing body containing the aqueous electrolyte is flexible, and the entire thermochemical battery is flexible, so that it can be adapted to a wide range of curved surfaces and uneven surfaces. Specifically, the problem is solved by the following means.

[0011] (1) A thermochemical battery comprising a pair of electrodes and an aqueous electrolyte present between and in contact with the pair of electrodes, capable of generating electricity when there is a temperature gradient difference between the pair of electrodes, characterized in that the battery has a flexible sealing body containing the aqueous electrolyte therein. (2) A thermochemical battery comprising a pair of electrodes and a pair of aqueous solution electrolytes present between the pair of electrodes in contact with the electrodes and separated by a separator, capable of generating electricity through an oxidation-reduction reaction between the pair of aqueous solution electrolytes and the pair of aqueous solution electrolytes in the vicinity of the surfaces of the pair of electrodes when the pair of aqueous solution electrolytes are at a predetermined temperature condition, characterized in that the battery is provided with a flexible sealing body containing the aqueous solution electrolytes therein. As described above, flexible thermochemical batteries are capable of continuous power generation, repeated use, and can be adapted to uneven surfaces, making them suitable for use in a variety of locations. (3) The flexible thermochemical battery according to (1) or (2), characterized in that the sealing body comprises the pair of flexible electrodes and a flexible and insulating case disposed between the ends of the pair of flexible electrodes, containing the aqueous electrolyte therein. Note that the term "between the ends of the pair of electrodes" also refers to the area between the outer edges of the pair of electrodes. According to this configuration, both the electrodes and the insulating case disposed between the ends of the electrodes are flexible, so that the thermochemical battery has excellent flexibility while maintaining its strength.

[0012] (4) The thermochemical battery according to (3), wherein the pair of flexible electrodes is a carbon sheet or a conductive polymer sheet. According to this configuration, the electrode is in a sheet form, which makes it easy to handle and leads to a thinner and lighter flexible thermochemical battery as a whole. (5) The flexible thermochemical battery according to (3) or (4), wherein the flexible and insulating case is made of rubber. According to this configuration, since the case is made of a rubber material, the entire thermochemical battery can more easily fit on an uneven surface. (6) The flexible thermochemical battery according to (4) or (5), characterized in that a conductive polymer sheet is provided on the electrolyte side of the pair of carbon sheet electrodes. According to this configuration, by disposing the conductive polymer material on the electrolyte side of the electrode, the oxidation-reduction reaction of the electrolyte in the aqueous solution is further activated, improving the characteristics of the battery.

[0013] (7) The flexible thermochemical battery according to any one of (3) to (6), further comprising an adhesive member between the electrode and the case, for bonding the electrode and the case together. With this configuration, the electrode and the case are firmly bonded together. (8) In the flexible thermochemical battery described in (7), the adhesive member comprises an adhesive on the electrode side, an adhesive on the case side, and a flexible substrate provided between the adhesive on the electrode side and the adhesive on the case side. With this configuration, the case and the electrodes can be bonded with different types of adhesives.

[0014] (9) In the flexible thermochemical battery described in (7), the adhesive member comprises an adhesive member having an adhesive on the electrode side and an adhesive provided between the case and the adhesive member to bond the adhesive member to the case, or an adhesive member having an adhesive on the case side and an adhesive provided between the electrode and the adhesive member to bond the adhesive member to the electrode. According to this configuration, when different types of adhesives are used to bond the case and the electrode, the case and the electrode can be bonded simply and easily by using an adhesive member on the electrode side or the case side. (10) The flexible thermochemical battery according to (8) or (9) is characterized in that the flexible and insulating case is made of silicone rubber, the pair of flexible electrodes are carbon sheets or conductive polymer sheets, the adhesive or pressure-sensitive adhesive on the electrode side is a non-silicone adhesive, and the adhesive or pressure-sensitive adhesive on the case side is a silicone adhesive. By using silicone rubber for the case, which has particularly excellent heat resistance and chemical resistance and a wide range of flexibility options, the durability of the thermochemical battery can be improved and the desired flexibility can be achieved. Furthermore, by selecting an adhesive appropriate for the material, the case and electrodes can be firmly bonded.

[0015] (11) A thermochemical battery module comprising a plurality of flexible thermochemical batteries according to any one of (1) to (10) electrically connected in series, which allows stable high power generation from a wide area of ​​a low-temperature heat source. (12) The flexible thermochemical battery module according to (11), characterized in that, between adjacent flexible thermochemical batteries connected in series, one of the pair of electrodes of one flexible thermochemical battery partially overlaps with the opposite electrode of the pair of electrodes of the other flexible thermochemical battery in a plan view, and a conductive member is provided at the overlapping portion to connect the one electrode with the opposite electrode. By providing a conductive member at the overlapping portion of the electrodes of adjacent thermochemical batteries, the conductive members can be easily connected and the strength is excellent. Furthermore, since adjacent thermochemical batteries can be arranged closely together, a compact and high-power module can be produced. (13) The thermochemical battery module according to (11) or (12), characterized in that the sealed body of the flexible thermochemical battery includes a pair of flexible electrodes and a flexible, insulating case disposed between the ends of the pair of flexible electrodes and containing the aqueous electrolyte. Between adjacent series-connected flexible thermochemical batteries, the adjacent side wall of the case of one flexible thermochemical battery also serves as the adjacent side wall of the case of the other flexible thermochemical battery. A conductive member is provided within the side wall, connecting one of the pair of electrodes of one flexible thermochemical battery to the opposite electrode of the other flexible thermochemical battery. The common side wall of the adjacent cases between adjacent flexible thermochemical batteries allows for a larger amount of electrolyte and a larger electrode surface area, enabling high power generation without increasing the size. Furthermore, the overall thermochemical battery module has a simple structure, leading to weight and cost savings. Furthermore, by providing the conductive members inside the side walls of the case, the conductive members are protected and the case has excellent impact resistance.

[0016] (14) A flexible thermochemical battery module comprising: a cylindrical outer frame; and partition members dividing the interior of the outer frame into a plurality of compartments; a flexible and insulating case; a pair of flexible electrodes sealing both ends of the opening of each compartment of the case; an aqueous electrolyte filled in each compartment and sealed by the case and the electrodes; and a conductive member electrically connecting the plurality of compartments in series, the conductive member being provided inside the partition member and connecting the electrode on one end of the opening of one of the adjacent compartments to the electrode on the other end of the opening of the other compartment; and capable of generating electricity when there is a temperature gradient difference between the electrode on one end of the opening of each compartment and the electrode on the other end of the opening. (15) A flexible thermochemical battery module comprising: a cylindrical outer frame and partition members dividing the interior of the outer frame into a plurality of compartments; a flexible and insulating case; a pair of flexible electrodes sealing both ends of the opening of each compartment of the case; a pair of aqueous solution electrolytes filled in each compartment and sealed by the case and the electrodes, separated by a separator arranged horizontally to the electrode surfaces; and a conductive member electrically connecting the plurality of compartments in series, the conductive member being provided inside the partition member and connecting an electrode at one end of an opening of one of the adjacent compartments to an electrode at the other end of the opening of the other compartment; and capable of generating electricity by an oxidation-reduction reaction between the electrolyte of each pair of aqueous solutions and the surfaces of each pair of electrodes when the electrolyte of each pair of aqueous solutions in each compartment is at a predetermined temperature condition. (16) A flexible thermochemical battery module according to (14) or (15), characterized in that the partition member, the portion to which the conductive member of the electrode on one end of the opening of one compartment is connected, and the portion to which the conductive member of the electrode on the other end of the opening of the other compartment is connected overlap in a planar view. By unitizing thermochemical batteries consisting of individual compartments, there are no gaps between the thermochemical batteries and no lost area, compared to a thermochemical battery module made up of multiple independent thermochemical batteries connected together, thereby improving the output density of the thermochemical battery module. [Effects of the Invention]

[0017] The thermochemical battery according to the present invention is flexible and can be placed on curved or uneven surfaces, making it versatile and expanding the range of applications. Furthermore, the thermochemical battery module according to the present invention can be used on a wide surface of a low-temperature heat source, making it possible to obtain high power. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram showing the configuration of a power generation type battery and the power generation principle. [Figure 2] FIG. 1 is a diagram showing the configuration of a rechargeable battery and the principle of power generation (in an equilibrium state). [Figure 3] 1 is a diagram showing the configuration of a rechargeable battery and the principle of power generation. [Figure 4] 1A is a plan view of a thermochemical battery of Embodiment 1, and FIG. 1B is a plan view of a case portion. [Figure 5] 4(A) is a side view (partial cross section) of the thermochemical battery shown in FIG. 4(A) viewed from various directions. [Figure 6] FIG. 2 is an enlarged side view (schematic diagram) of a joint portion between an electrode and a case. [Figure 7] FIG. 1 is a side view (partial cross section) of a rechargeable flexible thermochemical battery. [Figure 8] 1A is a plan view of a thermochemical battery module according to a second embodiment, and FIG. 1B is a side view (partial cross section) thereof. [Figure 9] 1A is a plan view of a thermochemical battery module according to a third embodiment, and FIG. 1B is a side view (partial cross section) thereof. [Figure 10] 1A is a plan view of a thermochemical battery module according to a fourth embodiment, and FIG. 1B is a side view (partial cross section) thereof. [Figure 11] 10A is a plan view of a thermochemical battery module of a fifth embodiment, and FIG. 10B is a plan view of a case portion. [Figure 12] 11(A) is a side view (partial cross section) of the thermochemical battery module shown in FIG. 11(A) as viewed from various directions. [Figure 13] Photograph of a flexible thermochemical battery. [Figure 14]FIG. 1 is a diagram showing an example of output from a flexible thermochemical battery (power generation type). [Figure 15] FIG. 1 is a diagram showing an example of output from a flexible thermochemical battery (rechargeable type). [Figure 16] FIG. 10 is a diagram showing an example of the output of a flexible thermochemical battery module. DETAILED DESCRIPTION OF THE INVENTION

[0019] Figure 1 shows the structure of a power generating type battery and the power generation principle. Electrodes (for example, carbon sheets or conductive polymer sheets) 1 are electrically connected via a resistor (load) and are in contact with the electrolyte 3 at both ends of the electrolyte so as to sandwich it.

[0020] As shown in FIG. 1(A), when there is no temperature difference between the electrodes 1 at both ends, the ion concentration inside the electrolyte is uniform and no potential difference occurs. A, A 3- , A 4- , e - represent the general atomic symbol, the trivalent anion of that atom, the tetravalent anion of that atom, and the electrons, respectively. Here, trivalent and tetravalent ions are exemplified, but the valence is not limited. 3- , A 4- As for CN - , C.N. 2- , Fe(CN)6 3- , Fe(CN)6 4- For ions, it is thought that the larger the formula weight, the greater the amount of energy transported by movement. However, when using a solution as an electrolyte, ions that are too large will not dissolve, so a balance must be struck.

[0021] Figure 1(B) shows an example where there is a temperature difference between the electrodes 1 at both ends (in the figure, the bottom is high temperature and the top is low temperature). On the surface of the upper and lower electrodes 1, the ions in the electrolyte (A 4- ) reacts and the valence changes to form an ion (A 3- ) and electrons (e -), electrons are generated (oxidized), and on the low-temperature side, the electrons react with the ions whose valence has changed due to the inflow of electrons, and the ions with the original valence (A 4- ) (reduction). In the electrolyte, differences in chemical reactions at the surfaces of both electrodes create differences in ion concentration, which leads to interdiffusion of ions. On the other hand, the generated electrons move from the high-temperature electrode to the low-temperature electrode along the external conductor 2, generating electricity, with the high-temperature side becoming the cathode and the low-temperature side becoming the anode. In this way, in a power-generating battery, the current flows in one direction.

[0022] 2 and 3 show the configuration of a rechargeable battery and a diagram of the power generation principle. In this specification, the term "rechargeable" is used to distinguish it from the power generation type battery (where the current flows in one direction), and refers to a thermochemical battery (where the current flows in two directions) in which the current direction changes depending on the temperature, as will be described later. Specifically, this refers to a type of thermochemical battery that can be used repeatedly by alternating the current direction between temperatures higher and lower than a certain temperature. The electrodes 1 at both ends are electrically connected via a resistor (load), and electrolytes 3a and 3b separated by a separating material (ion-permeable membrane) 4 are in contact with one end opposite the separating material 4, respectively.

[0023] The electrolytes 3a and 3b are different types of electrolytes, but they each have a common ion (cation or anion) (in the illustrated example, A +) The electrolytes 3a and 3b undergo different reactions, and the temperature dependence of their reaction rates differs. For example, at a certain temperature, the reaction rates of the electrolytes 3a and 3b are the same (equilibrium state), and at other temperatures, the reaction rates of the electrolytes 3a and 3b differ. It is assumed that the reaction rate of the electrolytes 3a (or the reaction rate of the electrolytes 3b) is higher at temperatures higher than the equilibrium state, and the reaction rate of the electrolytes 3b (or the reaction rate of the electrolytes 3a) is higher at temperatures lower than the equilibrium state. In this case, the reaction of the electrolytes 3a (or 3b) occurs preferentially at temperatures higher than the equilibrium state, and the reaction of the electrolytes 3b (or 3a) occurs preferentially at temperatures lower than the equilibrium state. It should be noted that even if there is a certain temperature range in the equilibrium state, the equilibrium state can be considered to exist as long as the temperature is such that no reaction can be confirmed.

[0024] When a reaction occurs between the electrolytes 3a and 3b, the common ions permeate the separation material 4. When the common ions are cations, the separation material 4 is a cation-permeable membrane (cation exchange membrane), and when the common ions are anions, the separation material 4 is an anion-permeable membrane (anion exchange membrane).

[0025] A, B, and C are general atomic symbols. e - represents electrons, and A represents + , B - , B 2- , C - , C 2- indicates ions and ions with changed valence. Fe as a cation 2+ , Fe 3+ , Cu + , Cu 2+ , Ag + , Pb 2+ , Pb 4+ The anion is CN - , C.N. 2- , Fe(CN)6 3- , Fe(CN)6 4-The valence of the ions, such as monovalent and divalent, is used as an example to explain the principle, and is not actually limited.

[0026] 2 shows the state of the electrolytes 3a and 3b under temperature conditions (the equilibrium state) where there is no difference in the reaction rates between the electrolytes 3a and 3b. In this state, no ion permeation occurs between the electrolytes 3a and 3b, and no electromotive force is generated.

[0027] For example, when the reaction rate of the electrolyte 3a is higher than that of the electrolyte 3b at a temperature higher than that at the equilibrium state, heating the whole system as shown in Figure 3(A) accelerates the oxidation reaction in the electrolyte 3a (AB → AB + A + + e - ) prevailed, and A + The electrons generated at the lower electrode 1 reach the upper electrode 1 through the external conductive wire 2. In this environment, electrons flow from the lower electrode 1 to the upper electrode 1, so the lower electrode becomes the cathode and the upper electrode becomes the anode, generating electricity and allowing the current that flows at this time to be utilized. + As the concentration of A increases, it becomes more concentrated in the electrolyte 3a and moves through the separator 4 to the upper electrolyte 3b. + Using the electrons that flow to the upper electrode 1, a reduction reaction (AC +A + + e - → A2C) occurs. Then, ion saturation (electrolyte 3a to A + The current stops when ions no longer move to the electrolyte 3b.

[0028] On the other hand, as shown in Figure 3(B), when the temperature is kept lower than the equilibrium state, the reverse reaction of Figure 3(A) occurs, and current flows in the opposite direction to that of Figure 3(A). In other words, when the temperature is lower than the equilibrium state temperature, the reaction rate of electrolyte 3b is higher than the reaction rate of electrolyte 3a. Therefore, in electrolyte 3b, A2C → AC + A + + e - (oxidation reaction) occurs, so A +The ions pass through the separator 4 and move to the lower electrolyte 3a, and electrons flow from the upper electrode 1 to the lower electrode 1 via the external conductive wire 2. In other words, the upper side becomes the cathode and the lower side becomes the anode, generating electricity, and current flows in the opposite direction to that shown in Figure 3(A), and the current that flows at this time can be utilized. In this case, too, current stops flowing due to ion saturation.

[0029] By exposing the entire device to different temperature environments (for example, by connecting it to and disconnecting it from a heat source), the steps in Figure 3(A) and Figure 3(B) can be repeated, allowing for repeated use. In other words, the device generates electricity in response to changes in the ambient temperature.

[0030] (Embodiment 1) FIG. 4 shows a plan view of the flexible thermochemical battery of this embodiment (FIG. 4(A)) and a plan view of the case (FIG. 4(B)), and FIG. 5 shows side views as viewed from each direction (arrow AC direction) of FIG. 4(A). For ease of understanding, the case portion is shown in cross section. Also, the lower electrodes are omitted from the plan view. This is also the case in the other drawings. And FIG. 6 shows an enlarged side view (schematic diagram) of the joint between the electrode and the case. This thermochemical battery corresponds to the power generation type described above. A side view (partial cross section) of a rechargeable flexible thermochemical battery is shown in Figure 7. The plan view of the rechargeable thermochemical battery is the same as that of the power-generating thermochemical battery (Figure 4).

[0031] The thermochemical battery 5 includes an aqueous electrolyte 30 and a flexible seal containing the electrolyte 30. The seal prevents leakage of the aqueous electrolyte (also referred to as electrolyte solution) 30, i.e., provides a liquid-tight seal. The seal is composed of a pair of flexible electrodes 10 sandwiching the electrolyte solution 30 and a flexible, insulating case 20 positioned between the ends of the pair of electrodes 10 and containing the electrolyte solution. The electrolyte 30 is an aqueous solution, and the seal containing the electrolyte 30 defines the outer shape of the thermochemical battery 5. This gives the thermochemical battery flexibility, allowing it to adapt to large, curved, or uneven surfaces. Note that flexibility refers to flexibility, but also refers to the property of being easily deformed when external force is applied, for example, with a finger. Each component is described in detail below.

[0032] (electrolyte) The electrolyte 30 can be any redox couple (a pair consisting of two types of ions that undergo an oxidation-reduction reaction) that can generate electricity, and can be applied to any thermochemical battery that uses an aqueous electrolyte. Therefore, it can be used not only for the power generation type but also for the charging type. Furthermore, from the viewpoint of chemical stability, redox couples often contain a metal element or a halogen element.

[0033] For example, iron(II) ions and iron(III) ions, cobalt(II) ions and cobalt(III) ions, iodide ions (I - ) and triiodide ion, ferrocyanide ion and ferricyanide ion, cobalt tris(bipyridine)(II) and cobalt tris(bipyridine)(III), etc. Among these, the redox couple consisting of ferrocyanide ion (potassium ferrocyanide, K4Fe(CN)6) and ferricyanide ion (potassium ferricyanide, K3Fe(CN)6) is preferred because it provides a high voltage and ionic conductivity.

[0034] It should be noted that gel-like (semi-solid) electrolytes are not included in the aqueous electrolyte 30. Aqueous electrolytes have better ionic conductivity and superior battery characteristics than gel-like electrolytes. Additives may be added to the electrolyte 30 to improve the electromotive force of the thermochemical battery. For example, additives such as guanidinium chloride (GdmCl), betaine (Bet, or more specifically, trimethylglycine), aminoguanidine chloride (AdmCl), and metformin chloride (MfmCl) can be used to improve the thermoelectric power. Other additives include ionic liquids (e.g., 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl). While additives may or may not be used, guanidinium chloride is particularly suitable for improving the electromotive force when ferrocyanide ions are used as the electrolyte, as it interacts strongly with the ferrocyanide ions, thereby increasing the electromotive force.

[0035] (case) The case 20 is a cylindrical frame made of a flexible and insulating material. While the shape of the case 20 is a rectangular frame in the example shown in FIG. 4(B), it may be circular, another polygonal shape, or a shape including curves and straight lines, without any particular limitation. The material of the case 20 is not particularly limited as long as it is flexible and insulating, and may be resin or general rubber. Examples of the material include various general-purpose or special synthetic rubbers, such as natural rubber, styrene butadiene rubber, chloroprene rubber, acrylonitrile rubber, butyl rubber, ethylene propylene rubber, urethane rubber, fluororubber, chlorosulfonated polyethylene rubber, and silicone rubber (hereinafter referred to as silicone), and these may be used alone or in combination.

[0036] Among these types, fluororubber and silicone are preferred from the viewpoint of heat resistance. For example, silicone can be used up to 200°C (temporarily up to 300°C). Silicone is also particularly preferred from the viewpoint of chemical resistance (reactivity with electrolytes), as it excels. Furthermore, the flexibility of silicone can be controlled by the ratio of monomer (skeleton agent) and crosslinking agent (binder) during production, so there is a wide range of flexibility options.

[0037] The case 20 is made of such a flexible material, which leads to weight reduction and cost reduction of the entire thermochemical battery. In addition, the case 20 forms the framework of the sealing body and functions as a pillar, and the flexibility of the case 20 makes it easier for the thermochemical battery to fit on curved or uneven surfaces.

[0038] (electrode) The pair of electrodes 10 serve as both the bottom and the lid of the case 20, and are arranged so as to contact the upper or lower end of the opening of the case 20, that is, to close the openings at both ends, as shown in FIG.

[0039] The electrode 10 may be made of any flexible, electrically conductive material. Examples of such materials include carbon and conductive polymers. Carbon-based electrodes are particularly preferred because they are highly corrosion-resistant, highly conductive, and inexpensive. Thin-film or sheet-like electrodes, such as carbon sheets (graphite sheets or carbon nanotube (CNT) sheets) and conductive polymer sheets, are also preferred because they are easy to handle and contribute to the thinning and weight reduction of the entire thermochemical battery. The use of sheet-like electrodes also allows the thermochemical battery to fit more easily on large, curved, or uneven surfaces. The graphite sheets, CNT sheets, conductive polymer sheets, and the like may be used alone or in combination. For example, a graphite sheet may be coated with CNTs, which have excellent electrical properties.

[0040] When using carbon electrodes, a conductive polymer material may be disposed on the electrolyte-side surface of the carbon electrode (excluding the surface bonded to the case). For example, disposing a conductive polymer sheet such as PEDOT / PSS (poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonic acid)) on the electrolyte-side surface of a graphite sheet or CNT sheet is preferable because it further activates the redox reaction and improves the battery's characteristics. Note that while it is preferable to dispose the conductive polymer material on both of the pair of electrodes 10, it may also be disposed on one of the electrodes 10.

[0041] Furthermore, when a sheet-like electrode such as a carbon sheet is used, coating the surface of the sheet-like electrode with a conductive polymer film or attaching a conductive polymer sheet allows the conductive polymer material to adhere to the electrode, improving conductivity. A conductive polymer film can be easily formed by spraying a conductive polymer filler onto the sheet-like electrode. Furthermore, when a conductive polymer sheet is used, production is easy because it can be simply attached.

[0042] (External connection electrode) External connection electrodes 40 are connected to the upper and lower electrodes 10, and an electrical circuit can be formed by connecting a device (not shown) to the external connection electrodes 40. The external connection electrodes 40 are not necessary; they can simply be connected to the upper and lower electrodes 10. The external connection electrodes 40 can be made of any flexible and conductive material, including conductive carbon fiber, fibers impregnated with conductive polymers, or metal wire. One end of each external connection electrode 40 is connected to the upper and lower electrodes, respectively, and the other end is connected to the device. The method for connecting the external connection electrodes 40 to the electrodes 10 and the device is not particularly limited, and may be welding, a detachable fastener such as a clip, or adhesive bonding with a conductive adhesive. The conductive adhesive may be an acrylic, epoxy, or urethane adhesive with a conductive component such as copper or silver dispersed therein.

[0043] (adhesive material) By interposing an adhesive member 50 (FIG. 6) between the electrode 10 and the case 20, the electrode 10 and the case 20 are firmly bonded together, enhancing the sealing effect. The adhesive member 50 may be any material that can join the case 20 and the electrode 10 and prevent leakage of the electrolyte solution 30. For example, an adhesive or an adhesive tape (adhesive member) having an adhesive (adhesive) on one or both sides may be used alone or in combination. Appropriate adhesives and adhesive methods may be selected depending on the type of case and electrode.

[0044] For example, if silicone is used as the material for case 20, it is preferable to use a silicone adhesive, which has better adhesive properties, than non-silicone adhesives such as acrylic, epoxy, or urethane adhesives. On the other hand, if a carbon electrode such as a carbon sheet or a conductive polymer material is used for electrode 10, a non-silicone adhesive is more suitable than a silicone adhesive.

[0045] In this way, when the adhesive suitable for bonding the case 20 is different from the adhesive suitable for bonding the electrode 10, the two can be firmly bonded by sandwiching a flexible planar substrate (e.g., a film, tape, sheet, thin film, etc.) between the case and the electrode, and applying suitable adhesives to the electrode side of the substrate and the case side of the substrate, respectively.

[0046] For example, many commercially available single-sided adhesive tapes are coated with adhesives such as acrylic or urethane adhesives, and by applying a different adhesive to the non-adhesive side of the adhesive tape, it is possible to simply and easily bond the case and electrode with a different type of adhesive.

[0047] 6 shows an enlarged view of the joint between the electrode 10 and the case 20. For ease of understanding, the components are shown partially separated. For example, when using a silicone case 20 and a graphite sheet electrode 10, one can use single-sided adhesive tape 52 as adhesive member 50, affixing the adhesive tape 52 to the electrode 10 side, and then applying a silicone-based adhesive 56 to the non-adhesive side of the adhesive tape or the case side to adhere the case side. In this specification, the adhesive on the adhesive surface of the adhesive tape is called an adhesive, but adhesion and adhesion are synonymous.

[0048] An example of adhesive tape 52 is a polyester film coated with acrylic adhesive 54. Graphite sheets have good adhesive properties even when non-silicone adhesives are used, and can be easily attached using adhesive tape 52. This also applies to CNT sheets and conductive polymer sheets. In addition, when a silicone adhesive is applied to the adhesive surface of the adhesive tape, the opposite of the above-mentioned case can be achieved by attaching the adhesive tape to the case side and then applying a versatile acrylic adhesive, for example, to the non-adhesive side of the adhesive tape to adhere the graphite sheet side.

[0049] Furthermore, when a highly water-repellent rubber such as silicone is used for case 20, it is advisable to impart hydrophilicity to the adhesive side surface of case 20 by performing a surface treatment such as ozone treatment, plasma treatment, corona treatment, or flame treatment. Ozone treatment is the most suitable hydrophilic treatment because it requires simple equipment and does not require special raw materials, and can be performed most easily and at low cost.

[0050] In this way, by subjecting the adhesive surface of the silicone to a surface treatment such as ozone treatment to render it hydrophilic, the adhesion between the case surface and the adhesive can be further improved. If a common adhesive is suitable for both the case 20 and the electrode 10, a single type of adhesive may be applied to one or both of the case 20 and the electrode 10 for adhesion, or double-sided adhesive tape may be used for ease of application. That is, if a rubber material other than silicone is used as the material for the case 20, a non-silicone adhesive or double-sided adhesive tape may be used as the adhesive member 50 between the electrode 10 and the case 20. The surface treatment may also be applied to other rubber materials, but not applying it does not particularly contribute to improved adhesion.

[0051] (Method of manufacturing a thermochemical battery) Next, a method for manufacturing a power-generating thermochemical battery will be described with reference to Figures 4 and 5. In this embodiment, a graphite sheet is used as the electrode 10, and the case 20 is made of silicone. First, two graphite sheets (of the same size and thickness) and a predetermined amount of electrolyte 30 containing a redox couple are prepared. Next, the case (frame material) 20 is made, but the order of these steps does not matter. The case 20 can be made by pouring silicone raw material into a mold, heating it to harden it, and then cutting it. Specifically, the method is as follows.

[0052] First, the base agent (silicone oil) and curing agent (cross-coupling agent) are mixed in a desired ratio (ranging from 1:1 to 100:1) and stirred for a certain period of time (e.g., about 1 hour) at a constant temperature (e.g., about 25°C). The mixing ratio of the base agent and curing agent can be appropriately selected to achieve the desired flexibility. After that, a vacuum is applied for a certain period of time (e.g., about 1 hour) at a certain pressure (e.g., about 50,000 Pa) and a certain temperature (e.g., about 25°C) to remove air bubbles. The mixture is then placed in a mold and solidified by a cross-coupling reaction at a certain temperature (e.g., about 70°C) for a certain period of time (e.g., about 12 hours). Using a non-static container, such as an anti-static plastic container, as the mold is preferable, as this facilitates the release of the silicone after molding. The center of the case 20 is then cut to form a cylindrical shape. The size of the cut is preferably larger because the thinner the cylindrical shape is in the radial direction, the greater the flexibility and the larger the amount of electrolyte that can be accommodated. However, an appropriate size can be selected depending on the material, taking into consideration the strength, the temperature difference between the upper and lower electrodes, and ensuring a certain degree of adhesive surface with the electrodes.

[0053] The overall size of case 20 is set to be the same as, slightly smaller than, or slightly larger than graphite sheet electrode 10. Specifically, the size should be such that the end of graphite sheet electrode 10 contacts the upper or lower end of case 20. In the illustrated example, case 20 is arranged along the edge of electrode 10, but it may be arranged at the end (closer to the end than the center) of electrode 10. Note that arranging case 20 at the edge of graphite sheet electrode 10 is preferable because it allows for a wide contact surface between electrolyte 30 and electrode 10.

[0054] Then, the graphite sheet electrode 10, which will become the bottom of the thermochemical battery, is adhered to the bottom of the case 20. This adhesion is performed as follows. Prior to this adhesion, it is advisable to perform a surface treatment such as ozone treatment on the surface of the case 20 to be adhered.

[0055] First, adhesive tape 52 with single-sided adhesive (e.g., acrylic adhesive 54) is attached to the edge of graphite sheet electrode 10, silicone adhesive 56 is applied to the surface opposite the adhesive surface of the adhesive tape, and the bottom end of case (silicone) 20 is placed on the applied surface and pressed to adhere. In this manner, the bottom end of the opening of case 20 can be closed. Silicone adhesive 56 may also be applied to case 20. Furthermore, the graphite sheet electrode 10 and case 20 may be bonded together using adhesive tape 52 in either order. Silicone adhesive 56 may be applied to case 20, adhesive tape 52 may be attached to the adhesive surface of adhesive tape 52, and then graphite sheet electrode 10 may be attached to the adhesive surface of adhesive tape 52. The adhesive 56 may not be applied by coating, but may also be sprayed, for example. This is also true for other embodiments. Then, once the adhesive 56 has hardened, the electrolyte 30 is poured in so as to avoid the presence of air bubbles.

[0056] Furthermore, graphite sheet electrode 10 is attached to the adhesive surface of adhesive tape 52, and after silicone adhesive 56 is applied to the entire upper end of case 20, the surface opposite to the adhesive surface of adhesive tape 52 is pressed against the applied surface and the lid is closed. In this way, electrolyte 30 is filled into the sealed body formed by case 20 and electrode 10, and a liquid-tight seal is achieved. Alternatively, graphite sheet electrode 10 may be attached after adhesive tape 52 is attached to the case side with silicone adhesive 56.

[0057] Furthermore, when the same adhesive is used for the electrode 10 and the case 20, they may be bonded using double-sided adhesive tape, or adhesive may be applied to one or both of the electrode 10 and case 20 to bond them together. Then, external connection electrodes 40 are connected to the edges of the upper and lower electrodes 10 using a conductive adhesive (not shown), and a device is connected to the external connection electrodes 40 to form an electric circuit.

[0058] Furthermore, by installing a separator (ion-permeable membrane) 34 that separates the electrolyte in the thermochemical battery, it can also be used as the rechargeable type (Fig. 7). The separator 34 may be a flexible ion-permeable membrane, and an appropriate ion-permeable membrane may be selected depending on the type of electrolyte 30 used. In this case, the ion-permeable membrane must be placed inside the case 21, which can be easily done by fabricating two cases 21a and 21b of equal size and sandwiching the ion-permeable membrane between these cases.

[0059] The case can be fabricated in the same way as for a thermochemical battery of the power generation type, and two identical cases can be fabricated using the same method, or one large case can be fabricated and cut horizontally into two. Note that it does not matter if the thickness (height) or size of the two cases differs slightly.

[0060] An electrode (e.g., a graphite sheet) 10 is then attached to the bottom of one case 21a to seal the bottom, electrolyte 30a is poured in, and an ion-permeable membrane 34 is attached to the top of the case to close the lid. The other case 21b is then attached on top of the ion-permeable membrane 34, electrolyte 30b is poured in, and an electrode 10 is attached to the top of the case to close the lid. The bonding method may be the same as in the case of the power-generating thermochemical battery 5.

[0061] If the case 21 is made of silicone, a silicone adhesive may be used to bond the cases 21a, 21b to the ion-permeable membrane 34. That is, in this case, the ion-permeable membrane 34 is attached to the adhesive surface of the adhesive tape 52, the cases 21a, 21b are entirely coated with the silicone-based adhesive 56, and the surface of the adhesive tape 52 opposite to the adhesive surface is pressed against the coated surface.

[0062] An example of a combination of the electrolytic solution 30a and the electrolytic solution 30b is a potassium chloride solution (or a potassium nitrate solution) and a mixed solution of potassium ferrocyanide and potassium ferricyanide. In this case, the ion-permeable membrane 34 is a cation-permeable membrane (the common ion is K). +) The cation-permeable membrane and the anion-permeable membrane can be selected appropriately depending on the type of electrolyte in the upper and lower electrolyte solutions. For example, when the above combination is a potassium chloride solution and a mixed solution of iron (II) chloride and iron (III) chloride, an anion-permeable membrane is formed (when the common ion is Cl). - The same ion-permeable membrane is used regardless of the material of the case 21, provided that the common ions of the electrolytes 30a and 30b are the same.

[0063] (operation) Next, the operation of the flexible thermochemical battery will be described. First, the operation of the power generating flexible thermochemical battery 5 will be described. A power-generating flexible thermochemical battery 5 is placed on a heat source, such as a hot drain pipe or a hot exhaust pipe. In this case, the lower electrode 10 is at a high temperature, and the upper electrode 10 is at a low temperature. As described above, ions in the electrolyte 30 react at the lower electrode 10 on the high-temperature side, becoming ions with a changed valence and electrons, while on the low-temperature side, the inflow of electrons causes ions to return to their original valence. Therefore, heat flows from bottom to top in the direction of arrow F (Figure 5), and current flows in the direction of arrow D. In this way, it can be used as a battery for a device.

[0064] Next, the operation of the rechargeable flexible thermochemical battery 6 will be described. In the case of a rechargeable flexible thermochemical battery 6, when it is kept in a heat source, for example, a warm room, the entire battery heats up (FIG. 3(A)), causing reactions in the electrolyte and on the electrode surfaces in both the upper and lower parts. In the illustrated example, ions (e.g., cations) in the electrolyte 30a produced by the preferential reaction move in the direction of arrow F (FIG. 7) from the lower side to the upper electrolyte 30b, and current flows in the direction of arrow D, generating electricity until the ions are saturated. If the thermochemical battery 6 is then placed at a different temperature, for example, outdoors in the cold, the opposite reaction occurs, causing the current to flow in the opposite direction, and electricity is generated again until the ions are saturated.

[0065] In the case of the charging type, even if there is a temperature difference between the upper and lower electrodes, the effects of the temperature difference can be ignored because the types of electrolytes 30a and 30b inside are different, and the behavior is different from that of the power generation type. Note that the direction of current when the temperature changes will differ depending on the type of electrolyte used in the upper and lower electrodes. Furthermore, in a rechargeable thermochemical battery, two cases 21a and 21b are stacked on top of each other, so the battery is slightly thicker than a power generating thermochemical battery, but this does not affect flexibility in any way.

[0066] As described above, the flexible thermochemical batteries 5 and 6 according to this embodiment can be used as the power generation type and the charging type, and therefore, if there is a heat source, the heat can be converted into electricity and stored, and therefore they are expected to be one of the means for recovering surrounding waste heat. Therefore, the flexible thermochemical batteries 5 and 6 according to this embodiment are capable of both continuous power generation and repeated use, and can be used in a variety of locations.

[0067] The flexible thermochemical batteries 5 and 6 according to this embodiment are useful for a variety of devices requiring flexibility. For example, they can be used as power sources for small devices and wearable devices such as mobile phones, audio recording and playback devices, wristwatches, video and still image cameras, temperature and humidity sensors, and body-attachable devices, as well as for animal management devices (GPS and temperature management sensors) and plant management devices (temperature and humidity sensors and sunlight sensors). The same applies to other embodiments. Potential heat sources include factory exhaust heat, equipment exhaust heat, exhaust pipes, drainage pipes, household exhaust heat, the human body, animals, geothermal heat, solar heat, and other sources.

[0068] In this embodiment, the sealed body consisting of the cases 20, 21 and the electrodes 10 itself forms the outer shape of the thermochemical battery, but other members such as a flexible cover may be added to the outside of the cases 20, 21 and the electrodes 10. If the cover overlaps the electrodes 10, it is advisable to use a thermally conductive material (for example, a metal thin film, a thermally conductive polymer, etc.). In this case, too, the entire thermochemical battery is flexible, making it applicable to a variety of locations.

[0069] Furthermore, although it is preferable that all components constituting the flexible thermochemical battery have flexibility, this does not mean that any components that do not have flexibility are excluded. This also applies to the other embodiments.

[0070] (Embodiment 2) In this embodiment, a plurality of thermochemical cells are electrically connected in series to form a thermochemical cell module. The voltage can be increased by electrically connecting multiple flexible thermochemical batteries of the power generation type shown in Embodiment 1 in series. In this case, the heat source is located on one end side of each pair of electrodes, so the heat flow is limited to one direction.

[0071] FIG. 8(A) shows a plan view of a thermochemical battery module 60 in which two thermochemical batteries 5 are connected, and FIG. 8(B) shows a side view (partial cross section) of FIG. 8(A). As shown in these figures, two thermochemical batteries 5 are electrically connected by connecting the external connection electrodes 40 of adjacent thermochemical batteries with a conductive member 70. The conductive member 70 connects the external connection electrode 40 of the low-temperature side (or high-temperature side) electrode 10 of one of the adjacent thermochemical batteries to the external connection electrode 40 of the high-temperature side (or low-temperature side) electrode 10 of the other thermochemical battery, and is disposed between the side walls of the cases 20 of the adjacent thermochemical batteries 5.

[0072] The conductive member 70 for connecting the external connection electrode 40 may be any conductive material that does not impair the flexibility of the connection portion. Furthermore, the conductive member 70 is preferably flexible and conductive, and is not particularly limited, and may be the same as the external connection electrode 40. For example, a metal wire or a fiber impregnated with a conductive polymer may be used. The same applies to other embodiments.

[0073] (Method of manufacturing a thermochemical battery module) Next, a method for manufacturing a thermochemical battery module will be described with reference to FIG. First, two thermochemical batteries 5 are fabricated in the same manner as in embodiment 1. Then, a linear conductive member 70 is prepared to electrically connect the two thermochemical batteries, and both ends of the conductive member 70 are connected to the external connection electrodes 40 using a conductive adhesive. This connection is not limited to the use of a conductive adhesive, and metal wires or fibers may be directly connected to each other, or other metal wires or conductive polymer-impregnated fibers may be used. The conductive adhesive may contain graphene, graphite particles, carbon nanotubes, etc. Even if no conductive adhesive is used, an aggregate of graphene, graphite particles, carbon nanotubes, etc. may be applied to the connection between the metal wire or conductive polymer-impregnated fiber and the external connection electrode 40. In order to increase the strength of the conductive member 70, a protective cover may be provided around the conductive member 70.

[0074] In this way, by directly connecting multiple external connection electrodes 40 of the thermochemical batteries 5, a thermochemical battery module 60 can be easily fabricated. On the other hand, a thermochemical battery without external connection electrodes 40 may be fabricated, and the edges of the upper and lower electrodes 10 may be connected only by the conductive member 70. Furthermore, by using a sealing material (not shown) on the opposing surfaces of the cases 20 of adjacent thermochemical batteries 5 and around the conductive member 70, the conductive member 70 is protected and the gap between the side walls can be filled.

[0075] (operation) The current flow in the thermochemical battery module 60 will now be described. When a thermochemical battery module 60 is placed on a heat source (for example, a hot drain pipe or a hot exhaust pipe), the electrode 10 on the ground side (hereinafter referred to as the lower side) becomes hot, and the electrode 10 on the opposite side to the ground side (hereinafter referred to as the upper side) becomes cold. Therefore, in both of the two thermochemical batteries 5 constituting the module, the lower electrode 10 becomes hot and the upper electrode 10 becomes cold, and heat flows from the lower side to the upper side in the direction of arrow F, and current flows from the upper electrode 10 in the direction of arrow D via the conductive member 70 to the lower electrode 10 of the adjacent thermochemical battery 5.

[0076] This flow causes a current to flow linearly (in the direction of arrow D) between the two thermochemical batteries 5. A DC circuit is formed by connecting a device to the external connection electrodes 40 on one end and the other end of the series-connected thermochemical batteries 5. The external connection electrode 40 is connected on the input side of the battery to the lower electrode 10, which is at a high temperature, and on the output side to the upper electrode 10, which is at a low temperature.

[0077] As described above, the thermochemical battery module 60 of this embodiment can stably obtain high power from a wide area of ​​a low-temperature heat source by connecting a plurality of thermochemical batteries 5. This is also true for the thermochemical battery modules of the other embodiments.

[0078] Although this embodiment shows an example in which two thermochemical batteries are connected, more than two thermochemical batteries may be connected. Furthermore, the invention is not limited to connecting identical thermochemical batteries, but may also connect thermochemical batteries of different shapes and sizes. Furthermore, the invention is not limited to connecting batteries in a straight line, but can also be connected in a bent shape, making it possible to accommodate any shape or size to fit the shape of the installation surface. It is also applicable to rechargeable thermochemical batteries. (Embodiment 3)

[0079] Fig. 9(A) shows a plan view of a thermochemical battery module in which two thermochemical batteries are connected, and Fig. 9(B) shows a side view (partial cross section) of Fig. 9(A). For ease of understanding, the conductive member inside the case side wall is shown as a cross section. This is also true for other embodiments. The thermochemical battery module 62 of this embodiment is similar to the thermochemical battery module of embodiment 2 in that it is a thermochemical battery module in which two thermochemical batteries 7 are connected, but differs from the thermochemical battery module of embodiment 2 in that the side walls of the adjacent cases of the two thermochemical batteries are common.

[0080] That is, the thermochemical battery module 60 of the second embodiment is configured by connecting two independent thermochemical batteries 5 in series, but in this embodiment, the cases of the two thermochemical batteries are unitized to obtain the same amount of power as the thermochemical battery module of the second embodiment. Furthermore, a pair of upper and lower electrodes are connected by a conductive member, instead of connecting the external connection electrodes of the thermochemical batteries.

[0081] The conductive member 72 connects the low temperature (or high temperature) electrode 12a of one of the adjacent thermochemical cells 7 to the high temperature (or low temperature) electrode 12a of the other thermochemical cell 7.

[0082] In the illustrated example, the pair of upper and lower electrodes 12 (12a, 12b) of the thermochemical battery are approximately the same size, but it is preferable that the sizes are slightly different so that the connecting portion 12aa (hereinafter referred to as the conductive connecting portion) of the conductive member 72 is wider in order to ensure space for this portion. That is, as shown in Fig. 9, of the pair of upper and lower electrodes 12, the length of the side in the current direction (direction of arrow D) of the electrode 12a having the conductive connecting portion 12aa is longer than that of the electrode 12b not having the conductive connecting portion.

[0083] (Method of manufacturing a thermochemical battery module) Next, a method for manufacturing a thermochemical battery module 62 will be described with reference to FIG. 9. As in the first embodiment, a case will be described in which graphite sheets are used as the electrodes 12 and the case 22 is made of silicone. Basically, it is the same as the method in the second embodiment, but two larger electrodes 12a and two smaller electrodes 12b are prepared as graphite sheets (electrodes). For example, the lengths of the short sides may be the same but the lengths of the long sides may be different. The electrolyte containing the redox couple may be the same as in the first embodiment.

[0084] Then, one or more, preferably a plurality, of linear conductive members 72 are prepared as many as necessary to electrically connect the thermochemical cells 7. These conductive members 72 may be similar to the conductive member 70 of the second embodiment and may have the same length. The conductive member 72 and the thermochemical cells may be connected using the same material as that used to connect the conductive member 70 of the second embodiment and the external connection electrode 40. The number and size of the conductive members 72 are not particularly limited, but they should be an appropriate number and size so as to maintain the strength of the side walls (partitions described below) of the case 22 and to provide an appropriate spacing in consideration of workability. This also applies to the thermochemical battery modules of other embodiments.

[0085] The case (frame material) 22 can be produced by basically the same method as the case of embodiment 1, except that the size and shape of the silicone molding mold are changed. In this case, the solidified material after molding is cut in two places in the longitudinal direction, so that the interior is divided into two compartments 22b by partition 22a.

[0086] Then, an electrode (graphite sheet) 12 that will form the bottom of the thermochemical battery 7 is adhered to the bottom of the case 22. At this time, electrodes 12a and 12b of different sizes are aligned and adhered to the case. The adhering method may be the same as in the first embodiment. Then, electrolyte 30 is poured into each of two compartments 22b separated by a partition 22a inside the case 22. After that, an electrode 12 is attached to the top of the case 22, and the lid is closed and pressed and adhered. At this time, in the compartment with the smaller electrode 12b attached to the bottom, a larger electrode 12a is attached above it, and in the compartment with the larger electrode 12a attached to the bottom, a smaller electrode 12b is attached above it. In other words, the larger electrodes 12a and the smaller electrodes 12b are arranged above and below the compartments 22b so that they are alternately positioned above and below. By arranging them in this manner, the conductive connection portion 12aa of the upper (or lower) electrode 12a of one adjacent section 22b and the conductive connection portion 12aa of the lower (or upper) electrode 12a of the other adjacent section 22b overlap in a planar view with the partition portion 22a.

[0087] Next, holes (not shown) for inserting the conductive members 72 are formed in the partition 22a of the case 22 and the upper and lower electrodes 12a, the number of which corresponds to the number of conductive members. The conductive members 72 are inserted into the holes to connect the upper and lower electrodes 12a. At this time, if necessary, they are fixed with an adhesive. Note that, because the electrolyte 30 is sealed in the partition 22a of the case 22 (the portion in contact with the graphite sheet), providing the conductive members 72 inside the partition 22a does not affect the sealing effect.

[0088] The external connection electrode 40 is then connected to the edge of the smaller electrode 12b of each thermochemical battery 7 in the same manner as in the first embodiment. It does not matter whether the external connection electrode 40 or the conductive member 72 is connected first. This also applies to the thermochemical battery modules of other embodiments. The shapes of the case 22 and the compartments 22b are not particularly limited, and may be circular, other polygonal, or have both curved and straight lines. The shape and size of the electrodes 12 are not particularly limited to this embodiment, as long as the conductive connection portions 12aa of the upper and lower electrodes of adjacent compartments 22b overlap or are adjacent to each other in a plan view. This also applies to the thermochemical battery modules of other embodiments having conductive connection portions.

[0089] (operation) The current flow in the thermochemical battery module 62 is the same as in the second embodiment, and when the thermochemical battery module 62 is placed on a heat source (for example, a hot drain pipe or a hot exhaust pipe), the lower electrodes 12 of the two thermochemical batteries constituting the module are both at high temperature and the upper electrodes 12 are at low temperature, and heat flows from the bottom to the top in the direction of arrow F. Accordingly, current flows in the direction of arrow D from the upper electrode 12a through the conductive member 72 to the lower electrode 12a.

[0090] This flow causes a current to flow linearly (in the direction of arrow D) between the two thermochemical cells 7. A DC circuit is formed by connecting a device to the external connection electrodes 40 on one and the other ends of the series-connected thermochemical cells 7. The external connection electrode 40 is connected on the input side of the battery to the lower electrode 12b, which is at a high temperature, and on the output side to the upper electrode 12b, which is at a low temperature.

[0091] As described above, in the thermochemical battery module 62 of this embodiment, between adjacent thermochemical batteries 7, the upper electrode 12a of one thermochemical battery partially overlaps the lower electrode 12a of the other thermochemical battery when viewed from above, i.e., perpendicular to the electrode surface. By disposing the conductive member 72 between the overlapping upper and lower electrodes 12a, the conductive member 72 can be easily connected and has excellent strength. Furthermore, since there are no gaps between adjacent thermochemical batteries, the module is compact and has high power.

[0092] Furthermore, the conductive member 72 is fixed and protected by being disposed within the partition portion 22a, which is the side wall of the case 22. Therefore, when the thermochemical battery module is bent, the conductive member 72 bends along with the case 22, resulting in high impact resistance and durability. Furthermore, the common side wall of the case 22 between adjacent flexible thermochemical batteries allows for a larger electrolyte volume and a larger electrode surface area, enabling high power output without increasing the module size. Furthermore, the entire thermochemical battery module 62 has a simple and compact structure, leading to weight and cost reductions. Furthermore, since multiple thermochemical batteries can be fabricated simultaneously in an integrated manner, the labor required to fabricate and connect independent thermochemical batteries is reduced, resulting in excellent workability.

[0093] Although this embodiment illustrates an example in which two thermochemical batteries are unitized, more than two thermochemical batteries may be unitized. Furthermore, the connection is not limited to a linear configuration, but can also be bent, allowing for various shapes and sizes to be accommodated according to the shape of the installation surface. Increasing the number of thermochemical battery connections tends to result in gaps at the connections, increasing the area loss. However, in this embodiment, the adjacent side walls of the thermochemical batteries are shared, thereby improving the output density (output per unit area) compared to the second embodiment. This embodiment can also be applied to rechargeable thermochemical batteries. In this embodiment, the conductive connection portions 12aa of the upper and lower electrodes 12a overlap in a planar view. However, even if the conductive connection portions 12aa of the upper and lower electrodes 12a do not overlap in a planar view, the conductive member 72 can be positioned within the partition portion 22a by adjusting the length of the conductive member 72 to connect the upper and lower electrodes 12a.

[0094] (Embodiment 4) Furthermore, as an example of electrically connecting a plurality of independent thermochemical cells, it is also possible to connect them without using external connection electrodes. FIG. 10(A) shows a plan view of a thermochemical battery module in which two thermochemical batteries are connected, and FIG. 10(B) shows a side view of FIG. 10(A). The thermochemical battery module 64 of this embodiment is similar to the thermochemical battery module 60 of embodiment 2 in that it is configured by connecting two independent thermochemical batteries 8 in series, but differs in that adjacent upper and lower electrodes 14a are connected directly without using external connection electrodes 40.

[0095] The upper and lower electrodes 14a are connected by a conductive member 74, and the upper (or lower) electrode 14a of one of the adjacent thermochemical cells 8 is arranged so as to partially overlap the lower (or upper) electrode 14a of the other thermochemical cell in plan view, which is common to the thermochemical battery module 62 of the third embodiment. That is, the larger electrodes 14a and the smaller electrodes 14b are arranged alternately above and below the case 20. The conductive member 74 and the thermochemical cells may be connected using the same material as that used to connect the conductive member 70 and the external connection electrode 40 of the second embodiment. Furthermore, a protective cover may be provided to increase the strength of the conductive member 74, or a sealant may be used on the opposing surfaces of the cases of adjacent thermochemical batteries 8 or around the conductive member 74 to fill the gap between the side walls. This embodiment also achieves the same effects as those of embodiments 2 and 3. It can also be applied to a rechargeable thermochemical battery.

[0096] (Embodiment 5) Like the thermochemical battery module of embodiment 3, this embodiment has a common side wall between adjacent cases of thermochemical batteries, but differs from the thermochemical battery module of embodiment 3 in that it is a thermochemical battery module in which four thermochemical batteries are connected.

[0097] Figure 11 shows a plan view of the flexible thermochemical battery module of this embodiment (Figure 11(A)) and a plan view of the case (Figure 11(B)), and Figure 12 shows a side view of the flexible thermochemical battery as viewed from each direction (arrow AC direction) of Figure 11(A). As shown in these figures, four thermochemical batteries 9 are electrically connected in series by conductive members 76. The conductive member 76 connects the low-temperature (or high-temperature) electrode 16 of one of the adjacent thermochemical batteries 9 to the high-temperature (or low-temperature) electrode 16 of the other thermochemical battery 9. The conductive member 76 may be connected to the thermochemical batteries using the same material as that used to connect the conductive member 70 and the external connection electrode 40 in the second embodiment. The pair of upper and lower electrodes 16 of each thermochemical battery 9 are approximately the same size, but may be elongated horizontally to ensure space for the conductive connection portions 16a. The pair of upper and lower electrodes 16 are arranged in each compartment 24b of the case 24 so that the long side corresponds to the direction of current (the direction of arrow D, the direction flowing through the conductive connection portions 16a).

[0098] (Method of manufacturing a thermochemical battery module) Next, a method for manufacturing a thermochemical battery module 66 will be described with reference to FIGS. 11 and 12. As in the third embodiment, a case will be described in which graphite sheets are used as the electrodes 16 and the case is made of silicone. Basically, the method is the same as in the third embodiment, but eight rectangular graphite sheets of the same size (four on each side) are prepared. The conductive connectors 16a connecting the upper and lower electrodes 16 may be provided on the long side edges of the rectangles. Making the graphite sheets the same size improves the workability and productivity of the thermochemical battery. Alternatively, as in the third embodiment, two types of graphite sheets of different sizes (for example, sheets with the same short side length but different long side lengths) may be prepared, each with four sheets.

[0099] That is, the shape and size of the conductive member 76 are not particularly limited as long as they can secure an installation space for the conductive member 76 and can close the openings of the compartments 24b of the case 24. This also applies to other thermochemical battery modules having conductive connections. The electrolyte solution containing the redox couple may be the same as that in the first embodiment.

[0100] Then, one or more, preferably a plurality, of linear conductive members 76 are prepared as many as necessary to electrically connect the thermochemical cells 9. These conductive members 76 may be the same as the conductive members 70 of the second embodiment and may have the same length. In the present embodiment, since four thermochemical cells are connected, conductive members 76 must be disposed at three connection locations (conductive connection portions 16a). The size, number, etc. of these conductive members 76 may be considered to be the same as those of the conductive members of the third embodiment.

[0101] Next, the case (frame material) 24 is produced, and by changing the size and shape of the mold for silicone molding, the same method as for the case of embodiment 1 may be basically used. In this case, the solidified material after molding is cut in four places on the left and right, forming a body whose interior is divided into four compartments 24b by partitions 24a.

[0102] Then, an electrode (graphite sheet) 16 that will become the bottom of the thermochemical battery 9 is adhered to the bottom of the case 24, with the graphite sheet being arranged so that the short and long sides of the rectangle in adjacent sections 24b are oriented in a staggered manner.

[0103] The bonding method may be the same as in the first embodiment. Then, the electrolyte 30 is poured into each of the four compartments separated by the partitions 24a inside the case 24. After that, the electrodes 16 are attached to the top of the case 24, and the lids are closed and pressed and bonded. At this time, the upper and lower electrodes 16 are arranged so that their vertical and horizontal orientations are staggered. By arranging them in this manner, the conductive connection 16a of the upper (or lower) electrode 16 of one adjacent compartment 24b and the conductive connection 16a and partitions 24a of the lower (or upper) electrode 16 of the other adjacent compartment 24b overlap in a plan view.

[0104] Next, holes (not shown) for inserting the conductive members 76 are formed in the partition 24a of the case 24 and the upper and lower electrodes 16, the number of which corresponds to the number of conductive members, and the conductive members 76 are inserted into the holes to connect the upper and lower electrodes 16. This connection is the same as in embodiment 3, so a description thereof will be omitted. This operation is performed in each section 24b. Then, external connection electrodes 40 are connected to the input and output electrodes 16 of the thermochemical battery module 66, as in embodiment 1. The shapes of the case 24 and the sections 24b are not particularly limited and may be circular, other polygonal shapes, or shapes including curves and straight lines.

[0105] (operation) The current flow in the thermochemical battery module 66 is the same as in Embodiments 2-4, but when the thermochemical battery module is placed on a heat source (for example, a hot drain pipe or a hot exhaust pipe), the lower electrodes 16 of all four thermochemical batteries 9 constituting the module become hot and the upper electrodes 16 become cold, and heat flows from bottom to top in the direction of arrow F (FIG. 12). Accordingly, current flows in the direction of arrow D from the upper electrode 16 to the lower electrode 16 via the conductive member 76.

[0106] This current causes a U-shaped current to flow between the four thermochemical cells 9 in a plan view (in the direction of arrow D) (FIG. 11). A DC circuit is formed by connecting a device to the external connection electrodes 40 on one end and the other end of the thermochemical cells 9 connected in series. The external connection electrode 40 is connected on the input side of the battery to the lower electrode 16, which is at a high temperature, and on the output side to the upper electrode 16, which is at a low temperature.

[0107] The thermochemical battery module of this embodiment achieves the same effects as those of the third embodiment. Although this embodiment illustrates an example in which four thermochemical batteries 9 are unitized, more than four thermochemical batteries may be unitized and spread two-dimensionally. For example, the thermochemical batteries may be arranged in a 3x3 array, a stepped or zigzag configuration in plan view, or any other configuration or size can be accommodated by changing the shape and size of the case to match the shape and size of the installation surface. This configuration can also be applied to rechargeable thermochemical batteries. Even if the conductive connection portions 16a of the upper and lower electrodes 16 do not overlap in plan view, the conductive member 76 may be positioned within the partition portion 24a by adjusting the length of the conductive member 76 to connect the upper and lower electrodes 16. [Example]

[0108] Example 1 A thermochemical battery (power generating type) was fabricated by the following method. As the electrode 10, a graphite sheet (manufactured by Panasonic Corporation, EYGS091210, area 4.5 cm) was used. 2 Two sheets of 1000-12000mm thick silicon dioxide powder (approximately 0.1 mm thick) were prepared. As the electrolyte 30, potassium ferrocyanide (KFe(CN)) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and potassium ferricyanide (KFe(CN)) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were mixed and stirred with guanidinium chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) so that the molar concentrations (mol / L) of the compounds were as follows: Potassium ferrocyanide (K4Fe(CN)6): potassium ferricyanide (K3Fe(CN)6): guanidinium chloride (CH6ClN3) = 0.4M: 0.4M: 1.0M

[0109] Next, a silicone rubber case 20 was fabricated using PDMS (polydimethylsiloxane, manufactured by Toray Dow Corning Co., Ltd., SILPOT 184, two-component mixture) as the raw material. First, the base resin and curing agent were mixed in a 10:1 ratio and stirred at 25°C for one hour. A vacuum was then applied at 50,000 Pa and 25°C for one hour. The product was then placed in a rectangular container (AS ONE Corporation, ABS non-chargeable rectangular case, 10-inch, external dimensions 194 mm x 104 mm x 26 mm) and allowed to solidify at 70°C for 12 hours.

[0110] The solidified material was then removed from the container and cut to a specified size (30 mm x 60 mm), after which the center was cut off to create a rectangular cylindrical case. Furthermore, both end faces of the case were surface treated with ozone in air at room temperature using a surface modification device (Asumi Giken Co., Ltd., ASM401N).

[0111] An adhesive tape with an acrylic adhesive (Scotch (registered trademark), VHB (registered trademark) acrylic foam structural bonding tape, Y-4920, manufactured by 3M Corporation) was then attached to the edge of the graphite sheet, and a silicone adhesive (MPX-1, manufactured by Konishi Co., Ltd.) was applied to the side of the tape opposite the adhesive, and the underside (the surface that will become the bottom) of the case was adhered to it. Next, the case was filled with the prepared electrolyte, and the top of the case was covered with a graphite sheet using silicone adhesive and adhesive tape, in the same manner as in the previous method.

[0112] The overall size of the fabricated thermochemical battery was 30 mm x 60 mm, and the thickness was approximately 4 mm (electrolyte part dimensions: 15 mm x 30 mm, thickness: 3.5 mm).

[0113] Figure 13 shows a photograph of the thermochemical battery when bent. As shown, the flexible thermochemical battery of this example can be easily bent with fingers, and even when kept in this state for more than a month, no leakage of electrolyte was observed. Therefore, the flexible thermochemical battery can be used not only on flat surfaces with curves or irregularities, but also by wrapping it around a person's arm or a pipe.

[0114] Example 2 A thermochemical battery (power generation type) was fabricated using natural rubber (GS-09, manufactured by Wake Sangyo Co., Ltd.) and special synthetic rubber (non-silicone type) (KGS-021, environmentally friendly rubber, manufactured by Wake Sangyo Co., Ltd.) as the materials for the case 20. The conditions other than the material of the case 20, i.e., the type of electrode and the composition of the electrolyte, were the same as in Example 1. Square cylindrical cases were fabricated by cutting the center of commercially available sheets of natural rubber and special synthetic rubber. The graphite sheet was cut to fit the size of each case. The size of the natural rubber case was 50 mm x 50 mm, and the special synthetic rubber case was 30 mm x 40 mm.

[0115] Thermochemical batteries were fabricated in the same manner as in Example 1, except that the adhesive surface of the case 20 was not surface-treated and double-sided adhesive tape (3M Corporation, Scotch (registered trademark), KPS-100, acrylic adhesive) was used to attach the electrode 10 to the case 20. The dimensions of the fabricated thermochemical batteries were 50 mm × 50 mm and approximately 4 mm thick (electrolyte part dimensions: 30 mm × 30 mm, 3.5 mm thick) for the natural rubber battery and 30 mm × 40 mm and approximately 4 mm thick (electrolyte part dimensions: 10 mm × 20 mm, 3.5 mm thick) for the special synthetic rubber battery. The amount of electrolyte was adjusted to meet the respective electrolyte part dimensions. Both thermochemical batteries were flexible, and no electrolyte leakage was observed with slight bending. However, when bent to the same extent as the thermochemical battery with the silicone case of Example 1 (FIG. 13), electrolyte leakage and cracking were observed. Therefore, it can be said that the thermochemical battery with the silicone case of Example 1 has better flexibility.

[0116] 14 shows the measurement results of the output characteristics of the thermochemical batteries of Examples 1 and 2. The horizontal axis represents voltage (mV) and the vertical axis represents output density (μW / cm 2 ) The black circle plots show the results for the thermochemical battery with the silicone case of Example 1, the black triangle plots show the results for the thermochemical battery with the natural rubber case of Example 2, and the square plots show the results for the thermochemical battery with the special synthetic rubber case of Example 2.

[0117] A hot plate was used as a heat source, with the high-temperature side temperature set to 28°C and the low-temperature side allowed to cool naturally (room temperature 25°C). Output power was measured by directly contacting the electrodes 10 of the thermochemical cell with external conductive wires 2 (Fig. 1) connected to a measuring instrument (Keithley Instruments, Inc., SourceMeter (registered trademark) 2400). No external resistor was used. The measurement time was 1 minute. As shown in Figure 14, even with a temperature difference of only 3°C, the radiation intensity is 0.25 to 1.6 μW / cm 2 With this level of output, several units can be connected together and a boost circuit can be used as a power source for a temperature and humidity sensor.

[0118] The results also showed that the output per unit area was overwhelmingly greater for thermochemical batteries with silicone cases. This is thought to be because silicone has a fairly low thermal conductivity, making it difficult for heat to be transferred from the lower electrode on the grounded side of the heat source to the upper electrode, maintaining a temperature difference between the upper and lower electrodes. In the case of thermochemical batteries with natural rubber cases and special synthetic rubber cases, it is thought that the temperature difference between the upper and lower electrodes was less likely to occur, resulting in lower output than would be the case if it were due to an actual temperature difference. Therefore, it can be said that thermochemical batteries with silicone cases are good in terms of output characteristics as well.

[0119] Example 3 A thermochemical battery (rechargeable type) was fabricated by the following method. A cation exchange membrane (CIMS, manufactured by Astom Corporation) was used as the separation material 34 (Figure 7), the composition of the electrolyte 30a was a mixed solution of potassium ferrocyanide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and potassium ferricyanide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and was adjusted to satisfy the following conditions, and the composition of the electrolyte 30b was a potassium chloride solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Composition of electrolyte 30a: potassium ferrocyanide (K4Fe(CN)6): potassium ferricyanide (K3Fe(CN)6): guanidinium chloride (CH6ClN3) = 0.4M: 0.4M: 1.0M Composition of electrolyte 30b: Potassium chloride solution 1.0M The type of electrode, the material of the case, the adhesive tape, the adhesives, etc. were the same as those in Example 1.

[0120] The silicone rubber case 21 was a rectangular cylindrical case (outer dimensions: 30 × 70 mm, electrolyte area: 4.0 cm) similar to that of Example 1. 2 Two cases (3.5 mm thick) were fabricated. Surface treatment was performed on both end surfaces of each of the cases 21a and 21b in the same manner as in Example 1.

[0121] Then, the graphite sheet and case 21a were bonded together using an acrylic adhesive tape and a silicone adhesive. Electrolyte 30a was poured into case 21a so as not to leave any voids. A cation exchange membrane was then bonded to the top surface of case 21a in the same manner as above, and the case was then covered. Case 21b was then bonded on top of the cation exchange membrane, and electrolyte 30b was poured into case 21b so as not to leave any voids. The top surface of case 21b was then covered with a graphite sheet. The overall size of the fabricated thermochemical battery was 30 mm x 70 mm, with a thickness of approximately 8.0 mm (electrolyte part dimensions: area 4.0 cm). 2 , thickness 7.0 mm).

[0122] The flexible thermochemical battery of this example could also be easily bent with fingers, and no leakage of electrolyte was observed even when bent to the same extent as the flexible thermochemical battery of Example 1 (FIG. 13). The measurement results of the output characteristics of the thermochemical battery are shown in Figure 15. Figure 15(A) shows the relationship between time and temperature, and Figure 15(B) shows the relationship between time and load voltage. The output was measured by directly contacting the external conductive wire 2 (Figs. 2 and 3) connected to a measuring instrument (Memory Hilogger LR8400, manufactured by Hioki E.E. Corporation) with the electrode 10 of the thermochemical battery. The resistance at this time was 40 Ω (ohms). The effective area of ​​the graphite sheet relative to the heat source (ground surface) is 4.0 cm 2 It was. The thermochemical battery was then placed in a temperature environment (temperature-controlled room) of 5°C and 60°C at regular intervals (30 minutes) and the load voltage was measured. These results showed that the thermochemical battery produced a voltage of approximately 40 mV at high temperatures and 30 mV in the opposite direction at low temperatures. It was also confirmed that the current flowed in the opposite direction at high and low temperatures, which means that the thermochemical battery can be used repeatedly.

[0123] Example 4 A thermochemical battery module was fabricated by unitizing four thermochemical batteries using the following method. The electrode type, electrolyte composition, case material, adhesive tape, and adhesives were the same as those used in Example 1. A rectangular graphite sheet (area 4.5 cm) was used as electrode 16. 2 Eight pieces of solidified electrolyte (approximately 0.1 mm thick) were prepared. Then, a rectangular container with an outer diameter of 194 mm × 104 mm (same as in Example 1) was used to prepare a unit case 24 (outer diameter 80 mm × 80 mm, electrolyte portion 20 mm × 22.5 mm, thickness 3.5 mm) in the same manner as in Example 1. At this time, the solidified material removed from the container was cut in four places on the left and right to prepare a unit case divided into 2 × 2 sections. Furthermore, both end surfaces of the case were subjected to a surface treatment with ozone in the same manner as in Example 1.

[0124] Four graphite sheets were then attached to the bottom of the case using adhesive tape and silicone adhesive, with the long and short sides of adjacent graphite sheets facing in opposite directions.

[0125] Next, electrolyte 30 was poured into each of the four compartments 24b in the case so that no voids were formed, and the top surfaces of the case 24 of each compartment 24b were covered with four graphite sheets in the same manner as in Example 1. At this time, the graphite sheets were arranged in such a way that the long and short sides of the upper and lower compartments 24b were oriented in a staggered manner, with the vertical and horizontal orientations reversed.

[0126] Seven holes were then drilled through the case divider 24a and the graphite sheets above and below it. Conductive carbon fibers (Epoch Corporation, carbon roving, G-08-020) 76 were inserted through the holes and sewn to the edges of the upper and lower graphite sheets. This process was repeated three times. The dimensions of the fabricated thermochemical battery module were 80 mm × 80 mm, and approximately 4 mm thick (each electrolyte part dimension: 20 mm × 22.5 mm, thickness: 3.5 mm).

[0127] FIG. 16 shows the measurement results of the output characteristics of the thermochemical battery module. The temperature on the high-temperature side was 37°C, and the low-temperature side was allowed to cool naturally. The temperature difference was 3°C (34°C when cooled naturally). The effective area for the heat source of four graphite sheets was 18cm. 2 (4.5cm 2 ×4). As in the thermochemical cells of Examples 1 and 2, a measuring instrument (SourceMeter (registered trademark) 2400 manufactured by Keithley Instruments Inc.) was used for the measurement, and the measurement time was 1 minute.

[0128] As shown in Figure 16, it was confirmed that an output of 33 μW was obtained even with a temperature difference of only 3°C. With this level of output, it can be used as a temperature sensor via various boost circuits, and it is also possible to transmit temperature information wirelessly to a mobile device. [Industrial Applicability]

[0129] The thermochemical battery of the present invention can be used as a power source without charging as long as there is a heat source, and can therefore be used as a power source for mobile devices, etc. Furthermore, because the thermochemical battery of the present invention is lightweight, harmless, inexpensive, and can fit on uneven surfaces, it may also be used as a power source for digital healthcare devices worn on the human body, devices for managing animals and plants, etc. [Explanation of symbols]

[0130] 1 electrode 2 Conductive wire 3 Electrolytes 4 Separation material 5, 6, 7, 8, 9 Thermochemical batteries 10, 12, 14, 16 electrodes 12a, 14a Larger electrodes 12b, 14b Smaller electrodes 20 and 21 cases 22, 24 cases (units) 22a, 24a Partition Sections 22b and 24b 30 Electrolyte (electrolyte) 34 Separation material (ion permeable membrane) 40 External connection electrode 50 Adhesive material 52 adhesive tape 54 Adhesive 56 Adhesive 60, 62, 64, 66 Thermochemical battery module 70, 72, 74, 76 Conductive members D Current direction F Heat flow direction

Claims

1. A thermochemical battery comprising a pair of electrodes and a pair of aqueous solution electrolytes present between the pair of electrodes in contact with the electrodes and separated by a separator, the thermochemical battery being capable of generating electricity through an oxidation-reduction reaction between the pair of aqueous solution electrolytes and the pair of aqueous solution electrolytes in the vicinity of the surfaces of the pair of electrodes when the pair of aqueous solution electrolytes are under a predetermined temperature condition, the predetermined temperature condition is a temperature condition in which a state with a heat source and a state without a heat source are alternately maintained; A flexible thermochemical battery having the aqueous electrolyte therein and comprising a flexible sealing body.

2. A thermochemical battery comprising a pair of electrodes and an aqueous electrolyte present between the pair of electrodes and in contact with the electrodes, the thermochemical battery being capable of generating electricity when there is a temperature gradient difference between the pair of electrodes, a flexible sealing body having the aqueous electrolyte solution therein; The sealing body is The pair of electrodes having flexibility; a flexible and insulating case disposed between the ends of the pair of flexible electrodes, the case containing the aqueous electrolyte solution therein; A flexible thermochemical battery comprising:

3. The sealing body is The pair of electrodes having flexibility; a flexible and insulating case disposed between the ends of the pair of flexible electrodes, the case containing the aqueous electrolyte solution therein; 10. The flexible thermochemical battery of claim 1, comprising:

4. 4. The flexible thermochemical battery according to claim 2, wherein the pair of flexible electrodes are carbon sheets or conductive polymer sheets.

5. 5. The flexible thermochemical battery according to claim 2, wherein the flexible and insulating case is made of rubber.

6. 6. The flexible thermochemical battery according to claim 4, wherein a conductive polymer sheet is provided on the electrolyte-side surfaces of the pair of carbon sheet electrodes.

7. 7. The flexible thermochemical battery according to claim 2, wherein an adhesive member is provided between the electrode and the case to bond the electrode and the case together.

8. 8. The flexible thermochemical battery according to claim 7, wherein the adhesive member comprises an adhesive on the electrode side, an adhesive on the case side, and a flexible substrate provided between the adhesive on the electrode side and the adhesive on the case side.

9. The adhesive member is an adhesive member having an adhesive on the electrode side, and an adhesive provided between the case and the adhesive member to bond the adhesive member to the case; or an adhesive member having an adhesive on the case side; and an adhesive provided between the electrode and the adhesive member, which bonds the adhesive member and the electrode.

8. The flexible thermochemical battery of claim 7.

10. the flexible and insulating case is made of silicone rubber; the pair of flexible electrodes are carbon sheets or conductive polymer sheets, the adhesive or pressure-sensitive adhesive on the electrode side is a non-silicone adhesive; The adhesive or pressure sensitive adhesive on the case side is a silicone adhesive.

10. The flexible thermochemical battery according to claim 8 or claim 9.

11. A flexible thermochemical battery module comprising a plurality of flexible thermochemical batteries according to any one of claims 1 to 10 electrically connected in series.

12. The flexible thermochemical battery module described in claim 11, characterized in that, between adjacent flexible thermochemical batteries connected in series, one of a pair of electrodes of one flexible thermochemical battery and the electrode of a pair of electrodes of the other flexible thermochemical battery opposite to the one electrode partially overlap in a planar view, and a conductive member connecting the one electrode and the opposite electrode is provided at the overlapping location.

13. the sealed body of the flexible thermochemical battery comprises the pair of flexible electrodes, and a flexible and insulating case disposed between ends of the pair of flexible electrodes, the case containing the aqueous electrolyte therein, In the adjacent flexible thermochemical batteries connected in series, the adjacent side wall of the case of one flexible thermochemical battery also serves as the adjacent side wall of the case of the other flexible thermochemical battery, The thermochemical battery module according to claim 11 or 12, characterized in that a conductive member is provided within the side wall, connecting one of a pair of electrodes of one flexible thermochemical battery to the opposite electrode of a pair of electrodes of the other flexible thermochemical battery.

14. a flexible and insulating case including a cylindrical outer frame and partition members that divide the interior of the outer frame into a plurality of compartments; a pair of flexible electrodes that close both ends of an opening of each compartment of the case; an aqueous electrolyte filled in each compartment and sealed by the case and electrodes; a conductive member that electrically connects the plurality of compartments in series, the conductive member being provided inside the partition member and connecting an electrode on one end side of an opening of one of the adjacent compartments to an electrode on the other end side of the opening of the other compartment; A flexible thermochemical battery module capable of generating electricity when there is a temperature gradient difference between the electrode on one end of the opening of each compartment and the electrode on the other end of the opening.

15. a flexible and insulating case including a cylindrical outer frame and partition members that divide the interior of the outer frame into a plurality of compartments; a pair of flexible electrodes that close both ends of an opening of each compartment of the case; a pair of aqueous electrolyte solutions filled in each compartment, sealed by the case and the electrodes, and separated by a separator arranged horizontally to the electrode surfaces; a conductive member that electrically connects the plurality of compartments in series, the conductive member being provided inside the partition member and connecting an electrode on one end side of an opening of one of the adjacent compartments to an electrode on the other end side of the opening of the other compartment; a flexible thermochemical battery module capable of generating electricity by an oxidation-reduction reaction between the electrolytes of each pair of aqueous solutions in each compartment and the surfaces of each pair of electrodes when the electrolytes are at a predetermined temperature condition, The flexible thermochemical battery module is characterized in that the predetermined temperature condition is a temperature condition in which a state with a heat source and a state without a heat source are alternately maintained.

16. 16. The flexible thermochemical battery module according to claim 14, wherein the partition member, the portion to which the conductive member of the electrode on one end of the opening of one compartment is connected, and the portion to which the conductive member of the electrode on the other end of the opening of the other compartment is connected overlap in a planar view.

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