Edible battery
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-06
- Publication Date
- 2026-08-13
Smart Images
Figure EP2026053165_13082026_PF_FP_ABST
Abstract
Description
[0001] EDIBLE BATTERY
[0002] The present invention relates to an edible battery for supplying energy to an electrical device, which is particularly dimensioned to be swallowable.
[0003] The development of edible electronic devices, for example for examining the gastrointestinal tract, is an area of increasing research activity. A prerequisite for this is energy supply systems that, for safety reasons, do not pose any negative health consequences for the user even if damaged. Typical high-energy-density batteries commonly used in medical applications are lithium coin cells. However, the materials used are not considered biocompatible, so while the battery cell itself may be "edible" in terms of size, the materials used are not. Insufficient compression of the casing can therefore lead to the leakage of battery fluid into the body.The same basic problem is also relevant for the majority of other batteries in miniaturized form, such as alkaline cells, silver oxide cells, mercury cells and ultimately also air-zinc cells, in which leakage of zinc can lead to diarrhea, nausea and vomiting.
[0004] US patent 2012 / 0289775 A1 discloses an edible battery that uses bodily digestive fluids, such as stomach acid, as electrolytes to provide energy for a measuring device. A disadvantage, however, is that the various bodily environments are not constant but depend heavily on ingested foods, pharmaceuticals, and other influencing factors.
[0005] US patent 2013 / 0 143 145 A1 discloses a battery with anodes and cathodes based on inorganic, specifically metallic, materials. While paragraph 0024 claims that the materials are "safe for human consumption," this is questionable. Elemental metals, and especially anionic materials like zinc and nickel, can cause nausea and vomiting. Furthermore, copper and nickel can have significantly stronger effects on people with contact allergies. Individuals with nickel / copper contact allergies exhibit burn- or scald-like symptoms even after just a few minutes of skin contact. The effects on the gastrointestinal tract are purely speculative. Magnesium dioxide also has a laxative effect. Overall, these materials cannot be considered biocompatible.
[0006] Furthermore, during operation when used inside the body, deposits can form on the external electrodes of the power supply device. These deposits can impede electron transport and make the power supply susceptible to malfunctions. Therefore, the power supply is not entirely self-sufficient within the body, but rather depends on the composition of the user's bodily fluids, which varies over time and depending on the user.
[0007] In 2023, a battery made from food or biocompatible components was described for the first time as part of university research: https: / / www.chemie.de / newsZ1180169 / eine-vollstaendig-essbare-und-wiederaufladbare-batterie-aus-lebensmitteln.html. However, studies on purely organic and biocompatible compounds of anode and cathode material showed a comparatively fast discharge of 2 minutes with a current output of 240 pA and an average voltage of 0.65 V. These properties appear insufficient for reaching specific locations in the human body with subsequent energy release of the desired magnitude, e.g., in the intestinal tract, thus severely limiting the application of this battery system.
[0008] Based on the previous state of the art, the objective of the present application is to provide an edible battery which does not have the aforementioned problems at all or at least to a reduced extent.
[0009] The present invention solves this problem by providing a battery which consists exclusively of biocompatible materials, i.e., with regard to edibility, of materials suitable for animal and human consumption and enables a self-sufficient energy supply, wherein the battery simultaneously has a high energy potential, so that a longer energy supply of an electrical device with a relevant amount of energy is guaranteed.
[0010] The edible battery is designed for insertion into a human or animal body. Accordingly, the battery is miniaturized. Furthermore, the battery consists exclusively of biocompatible components, which, given its edibility, are preferably foodstuffs and food-grade materials. Insertion can occur through various body orifices, with oral ingestion being particularly preferred.
[0011] "Tolerable by the body" essentially means that the components, in their intended composition, have no negative long-term or acute health effects in a person without pre-existing conditions, in average health, without organ insufficiency, and / or without nutritional deficiencies. The relevant concentrations can be determined by a professional using textbook tables in the food sector. The safety of ingredients is usually indicated by concentration ranges. A professional can find this information, in particular, in the lists of EU-approved food additives. The established acceptable daily intakes (ADIs) are regulated by the European Food Safety Authority (EFSA).
[0012] Preferably, all battery components are approved as food and / or as ingredients for food supplements, e.g. for iron(III) compounds.
[0013] The battery according to the invention has a housing with at least two compartments separated from each other by an ion-permeable membrane. The housing can be made, for example, of a plastic, preferably an electrically non-conductive plastic and / or a biodegradable plastic, such as polylactic acid (PLA) and / or a natural polymer compound, which may additionally be coated with a layer of beeswax.
[0014] One of the rooms has a cathode and a second of the rooms has an anode.
[0015] In each of the compartments, at least in some areas, a potential tap in the form of an electrode is provided. This potential tap serves to divert a potential from one of the two compartments to an area outside the casing. The edible battery is composed exclusively of biocompatible materials. As mentioned earlier, initial scientific approaches for such batteries are known. However, for the application described above, batteries with anode-cathode pairings made exclusively of organic compounds have been created. Nevertheless, the open-circuit voltages of the batteries known from the literature so far are only constant for a short period, and very rapid discharge occurs when a load is connected. Furthermore, the electrolyte components of the anode and cathode do not exhibit the required electrode potentials in their storage state.The potential difference between the cathode and the anode must first be built up through an initial charging process.
[0016] The edible battery according to the invention makes it possible to avoid these disadvantages.
[0017] For this purpose, the anode comprises a biocompatible anode material, in particular a biocompatible solution, containing redox-active organic molecules and / or anions. To optimize electron exchange, the biocompatible anode solution has an alkaline pH and is preferably composed of a free-flowing material, allowing for space-optimized filling of the casing with a large quantity of anode material. This impacts the amount of energy generated and the compactness of the battery, which are important factors considering the possibility of swallowing the battery.
[0018] Particularly preferred for the redox-active organic molecules and / or anions is at least one naturally occurring, biocompatible compound from the class of organic acids, especially fruit acids, carbohydrates and / or polyphenol compounds, as well as natural amino acids.
[0019] The cathode features a biocompatible cathode material, in particular a biocompatible solution, with redox-active inorganic cations.
[0020] In principle, the anode and cathode materials are designed as thickened liquids. However, a solid-state battery implementation is also possible in the future.
[0021] Redox-active inorganic cations have not previously played a role in the development of edible batteries. However, the use of such cations for the cathode allows for the creation of a larger potential difference compared to the electrode potential of the anode. Furthermore, a comparatively high open-circuit voltage can be maintained for a long period of several hours, instead of just a few minutes as before, which significantly expands their application as energy storage devices, particularly in the medical field.
[0022] Moreover, the batteries with redox-active inorganic cations can be used immediately without prior charging, which is also a great advantage for the application.
[0023] Further advantageous embodiments of the invention are the subject of the dependent claims.
[0024] It is advantageous if the biocompatible solution of the anode or anode material has an alkaline pH and is preferably composed of a flowable material, in particular a thickened or gelled material. The same preferably applies to the biocompatible solution of the cathode or cathode material. This also facilitates, among other things, improved handling during manufacturing.
[0025] Furthermore, an alkaline pH is advantageous because it allows the formation of redox-active organic molecules and / or anions from naturally occurring, biocompatible polyphenol compounds, vitamins, organic acids (especially organic fruit acids), and / or amino acids, thereby increasing their water solubility. These redox-active organic anions and / or molecules can then be digested by the body.
[0026] The ingredients of matcha tea and / or pomegranate peel extract are particularly favored due to their comparatively low redox potential in alkaline solutions. Individual ingredients, or especially the aforementioned tea or extract, can be used as an anion source in the biocompatible solution of the anode. Alternatively, gallic acid, cysteine (especially L-cysteine), ascorbic acid, and / or tocopherol can also be used as an anion source.
[0027] The biocompatible solution of the anode or anode material can contain at least 5 wt.%, preferably at least 9 wt.%, and particularly preferably between 10 and 30 wt.% of a natural or naturally occurring amino acid, preferably cysteine, especially L-cysteine, as an anion source. It is also advantageous if the pH of the biocompatible solution of the anode or anode material is adjusted to a pH between 8 and 11, preferably between 8.5 and 10.5, and particularly preferably between 8.8 and 9.5.
[0028] The biocompatible solution of the anode or the anode material can contain a pH buffer, preferably an ammonia / ammonium buffer, to adjust a fixed pH value in the aforementioned range.
[0029] Furthermore, it is advantageous if the biocompatible solution of the cathode or cathode material is formed as an acidic solution with a pH value less than pH=7 from a flowable material.
[0030] The redox-active inorganic cations can be in the form of biocompatible metal ions, preferably iron ions, particularly preferably iron(III) ions.
[0031] Alternatively or additionally, organic acids with polyphenolic character can also be used as a source of redox-active cations. However, this is less advantageous than the use of redox-active inorganic cations for various reasons, including potential difference and usability without prior charging.
[0032] Iron(III) sulfate can be used as a biocompatible cation source to provide iron(III) ions in solution. Alternatively, iron(III) compounds with organic anions can also be used. Numerous biocompatible iron(III) compounds are known. They are used, for example, in fruit juices, dietary supplements, and in medical therapy.
[0033] The compound for providing the iron ions, in particular the iron(III) ions, for providing a particularly high amount of energy, can advantageously be present in the solution at least to 5 wt.%, preferably at least to 9 wt.%, particularly preferably between 10 and 30 wt.%.
[0034] The pH of the biocompatible solution of the cathode or cathode material can, in order to create a particularly high potential difference with respect to the anode, be adjusted to a pH below 6, preferably between 0.5 and 5, and more preferably between 0.5 and 3.5. To maintain a constant value within the aforementioned range, the biocompatible solution of the cathode can include a pH buffer, preferably a citric acid-citrate buffer, and more preferably a 0.3 molar buffer.
[0035] Like any battery, the edible battery has separate anode and cathode compartments. This requires a separator that acts as an ion-permeable diaphragm, dividing the edible battery's capsule into an anode and a cathode compartment.
[0036] Another aspect of the invention is the provision of an ion-permeable separation membrane based on a protein compound, in particular a structural protein-containing material. Following several comparative tests with other biocompatible materials, such as natural intestine, a collagen diaphragm has proven to be particularly suitable.
[0037] Furthermore, the housing can advantageously have a sealing material or be formed from a sealing material, wherein the sealing material is a wax and / or rubber, preferably a beeswax and / or a natural rubber, such as gum arabic.
[0038] The battery casing can be optimized for oral administration. At the same time, sufficient volume should be provided for the biocompatible anode and cathode solutions. An optimal compromise is an external volume of less than 5000 mm³. 3 , preferably less than 4000 mm3 , and especially preferably between 1000-3500 mm 3 dar.
[0039] The housing can be designed as a medium-tight sealed capsule, preferably with two shell-shaped capsule bodies which are connected to each other along an interface in a medium-tight manner, preferably by the aforementioned sealing agent. These available components for forming a housing are an important building block for the mass production of the battery according to the invention.
[0040] It logically follows from the application that the capsule should be swallowable. Ideally, it consists of a water-resistant and / or water-repellent material or is coated with such a material. Biopolymers, particularly preferably those based on proteins or carbohydrates, are preferred capsule materials. Most preferably, the capsule or a coating applied to it may consist predominantly (more than 50% by weight) of gelatin, cellulose, chitin, and / or chitosan, or of a material based on one or more of these substances, such as a hydrolysis product like hydrolyzed gelatin or an iron-modified product like ethylcellulose.
[0041] Alternatively or additionally, the coating may also comprise or consist of another water-repellent material suitable for consumption, preferably of plant or animal origin.
[0042] The biocompatible solution of the anode and / or cathode, or of the anode and / or cathode material, may also contain a thickening agent. This makes leakage of the battery more difficult. The solution is therefore highly viscous, but still fluid.
[0043] The thickening agent can be a mixture of a plant-based thickener, preferably starch, particularly preferably potato or corn starch, and / or a carbon compound, especially activated carbon powder. However, it can also consist solely of the carbon compound, preferably in powder form and particularly preferably as powdered activated carbon. Graphite is also suitable.
[0044] In the biocompatible solution of the anode and / or the cathode or the anode and / or cathode material, an agent for reducing the internal resistance, preferably a particulate carbon compound, particularly preferably activated carbon powder, can be used.
[0045] The potential tap can be designed as a current collector and can also have a support consisting of a flexible carrier material, preferably a flexible carrier. This reduces the risk of injury when the battery is ingested orally.
[0046] The substrate can be coated on two opposite sides with a material that has a higher electrical conductivity than the substrate itself. Preferably, the substrate is made of a non-conductive material. Edible precious metals in leaf form are particularly suitable for this purpose.
[0047] Applying gold, for example, to sheets is both material-saving and particularly biocompatible. To intensify the contact between the electrodes and the redox-active electrode materials, the carrier materials, which are preferably ethylcellulose films, are coated on both sides with precious metal.
[0048] The carrier can preferably be designed as a non-conductor and the material layer arranged on the carrier, preferably on both sides, can be designed as an electrical conductor.
[0049] A method according to the invention for producing the battery according to the invention comprises the following steps:
[0050] a) Providing two potential taps, in particular in the form of current collectors, two shell-shaped capsule bodies and two thickened biocompatible solutions as anode and cathode material;
[0051] b) Filling the capsule bodies of a housing with each of the aforementioned thickened solutions and joining the capsule bodies together by inserting a separating membrane;
[0052] c) Inserting one of the aforementioned potential taps through the housing wall, in particular through a hole in the housing wall.
[0053] Furthermore, according to the invention, the edible battery according to the invention is used to supply energy to an orally ingested electrical device, in particular a medical diagnostic device, in the intended ingested state.
[0054] Also according to the invention is the use of the edible battery according to the invention for supplying energy to an electrical device, wherein no charging process of the battery takes place between its manufacture and its intended use. In other words, the potential difference between the electrodes does not first need to be built up by a charging process; rather, the battery is ready for use immediately after its manufacture. This is not the case with the edible batteries known to date as a result of university research.
[0055] The electrical devices described above can deliver an average discharge voltage of 0.7 - 0.9 V with a capacity of 1500 - 3625 pAh for a current draw of 500 pA over a period of at least 3 h.
[0056] The invention will now be explained in more detail with reference to several embodiments and the accompanying figures. These show:
[0057] Fig. 1 Experimental setup for determining redox-active electrode materials;
[0058] Fig. 2: Table of several measurement data obtained through the experimental setup;
[0059] Fig. 3 Table of cathode-anode material combinations
[0060] Fig. 4 Test system for verifying the performance of various galvanic cells from the determined electrode materials;
[0061] Fig. 5 shows the underlying redox reactions for several selected electrode materials;
[0062] Fig. 6 Measurement diagram showing the time course of the energy generated by a first selected electrode pairing;
[0063] Fig. 7 Measured open-circuit voltage and current of the electrode pairing of Fig. 6 for several discharge cycles;
[0064] Fig. 8 Measurement diagram showing the time course of the energy generated by a second selected electrode pairing;
[0065] Fig. 9 Measured open-circuit voltage and current of the electrode pairing of Fig. 8 for several discharge cycles;
[0066] Fig. 10 Measured open-circuit voltage and current of a third electrode pair for several discharge cycles; Fig. 11 Test system for determining a suitable separator material;
[0067] Fig. 12 Charging and discharging curve of a state-of-the-art reference battery;
[0068] Fig. 13 Charging and discharging curve of a battery variant according to the invention;
[0069] Fig. 14 Measured values for charging and discharging behavior;
[0070] Fig. 15 Basic structure of a variant of an edible battery according to the invention;
[0071] Fig. 16 tabular list of the materials required for the construction in Fig. 15;
[0072] Fig. 17 Cyclic voltammogram for the anode and cathode against Ag / AgCl;
[0073] and
[0074] Fig. 18 Procedure diagram for providing the battery of Fig. 15.
[0075] Like any battery, the edible battery contains substances that donate electrons (anode) and accept electrons (cathode). The voltage generated by the battery results from the potential difference between the redox-active anode and cathode materials. For the battery to have a sufficient electrical potential, the redox-active anode material must have the lowest possible redox potential, and the redox-active cathode material the highest possible redox potential.
[0076] A first central aspect of the present invention is the finding of suitable biocompatible electrode materials with suitable redox potentials.
[0077] Fig. 1 shows an experimental setup for determining suitable redox-active electrode materials for use in a battery. The experimental setup corresponds to a standard hydrogen electrode NHE 101. The electrode potentials were determined relative to the standard hydrogen electrode shown in Fig. 1, which had a basic structure of a Petri dish 102 with partitions 103 arranged therein, dividing the Petri dish 102 into three separate areas 104, 105, and 106. The electrode potentials were determined without additional pressurized hydrogen gas.
[0078] A 1 M HCl solution is placed in one third of dish 104, and the aqueous electrolyte solutions listed in the table in Fig. 2 are placed in the other third. Only 5–7 ml of liquid are required in each case. Salt bridges in the form of conductive beer mat tabs were placed on the partitions. Platinum wire 107 was used to measure the potential in the solutions in the separated compartments 104–106. After hydrogen was deposited on the platinum reference wire in dish 104 in the hydrochloric acid using a magnesium ribbon 108, the determined standard potential can be read precisely.
[0079] Electrode potentials are determined relative to the NHE as a reference electrode. To prepare the respective electrolyte solution, a comparable amount of the respective test substance is dissolved in H₂O or in NaHSO₄-Na₂CO₃ or NaHCO₃ solutions adjusted to pH values of 0.97, 2.19, 8.35, 9.76, and 11.84.
[0080] The corresponding results can be read directly from a control and / or evaluation unit 108.
[0081] The measured values of the electrode potentials are then shown in Fig. 2. Many of the substances selected in Fig. 2 belong to the natural polyphenols (caffeic acid, gallic acid, green tea, cocoa, tannins).
[0082] Working in alkaline solutions is recommended because the polyphenols form phenolate groups and thus become more soluble. In the electrolyte solutions – ROAS for short – shown in Fig. 2, sugars, amino acids, and peptides were also measured for comparison purposes.
[0083] Of the inorganic cations suitable for the cathode material, Fe(III) ions were selected as preferred species. Iron occurs in the human body as both Fe²⁺ and Fe³⁺ ions. The majority of iron ingested with food is in the Fe(III) form. Although the iron(III) sulfate related to the invention is not explicitly approved as a food additive, it is noted that iron(III) species, in combination with other anions, are used in dietary supplements and in medical therapy. Iron ion compounds with organic anions are also referred to as inorganic cathode material within the meaning of the present invention due to their cationic nature. Other preferred alternative or additional electrolyte species for the inorganic cathode include, among others, iron(III) gluconate and / or iron(III) hydroxide sucrose.
[0084] The measured electrode potentials, abbreviated ROAS (for redox-active substances) in Fig. 2, show that potentials with values < 0 could not be determined. Matcha tea and pomegranate, in addition to cysteine, exhibit surprisingly low potential values in alkaline solutions at pH ~12.
[0085] Matcha tea is a green tea containing approximately 35% polyphenols in its dry weight. Half of this is epigallocatechin gallate, an ester of gallic acid and the alcohol epigallocatechin with a total of 8 OH groups. Pomegranate peel has a higher polyphenol content than green tea. According to the literature, it contains, among other things, the polyphenols punicalin, punicalagin, caffeic acid, ferulic acid, ellagic acid, chlorogenic acid, gallic acid, catechins, and rutin.
[0086] After measurement, gallic acid, matcha tea, pomegranate peel, ascorbic acid, cysteine in reduced form and tocopherol were identified as particularly favorable anode materials, which exhibited a potential of less than 0.05 V in an alkaline environment, especially at a pH value of more than 10.0.
[0087] In contrast, of the identified cathode materials, only the iron(III) salt solution made from iron(III) sulfate solution in an acidic environment, particularly at a pH value less than 4.0, preferably between pH 0.7 and pH 2.2, exhibits an electrode potential of more than 0.7 V.
[0088] By combining the materials identified in Fig. 2 to form galvanic cells in the experimental setup of Fig. 1, the preferred combinations shown in Fig. 3 of iron (III) at a pH value less than 4.0 and cysteine or matcha tea or pomegranate peel are obtained, each in an alkaline solution, preferably in the range between pH=9.0-12.5.
[0089] The suitability of electrolyte pairing is not limited to edible batteries or batteries in miniaturized form. For example, a so-called redox flow battery can also be realized using electrolyte pairing. The simulation of such a battery was carried out according to the experimental setup shown in Fig. 4.
[0090] For this purpose, a clay pot 203 without a bottom hole was placed as a second cell in a beaker 201 filled with electrolyte 202. The ion-permeable wall of the clay pot 203 acts as both a separator and an ion bridge. The solution of the anode material 204 is located in the clay pot 203, and the solution of the cathode material 205 is located in the beaker 201 outside the clay pot 203.
[0091] The circulation of the redox couples in both areas is simulated using magnetic stir bars 206 and a magnetic stirrer 207. A graphite felt electrode 208 serves for potential measurement. This setup was intended to gather further information on current, voltage, and electrode potentials during several charge and discharge cycles. A setup 209 shown in Fig. 4, connected to measuring units 210, allows the display of the individual electrode potentials, the total voltage, and the current under load.
[0092] In the experimental variant, resistors 211 were included as consumers in the circuit and the potentials of ROAS vs. NHE were determined in three-part Petri dishes.
[0093] Filter paper strips soaked in electrolyte were used as ion bridges. Beaker 201 was filled with 200 ml of a 20% Fe₂(SO₄)₃ ■ n H₂O solution as the cathode substance. No further electrolyte is required. The pH is lowered to below 1 by the acidic iron salt.
[0094] Clay pot 203 was filled with an infusion of matcha tea (10 g), an extract of pureed pomegranate peel (20 g) (each in 0 ml of hot Na2CO3 solution) or 100 ml of cysteine solution in Na2CO3 / NaHCO3 (20%) as anode materials.
[0095] The polyphenol-rich, brown-black soda extracts from matcha tea and pomegranate peel still contained gelatinous plant residues that could not be separated by paper filters. These were removed using a fine tea strainer. As shown in Fig. 8 and the tables in Figs. 9 and 10, the extracted polyphenols proved to be good electron donors. It can be assumed that their oxidation occurs with the formation of quinoid structures. The relevant redox processes are shown in Fig. 5. Fig. 6 shows the results with cysteine solution, in particular L-cysteine, as the anode material and Fe(llI) solution as the cathode material, based on measurement curves 701-704. The assignment of the measurement curves to the measured quantity is directly evident from the legend of the measurement diagram. The second of three discharge processes over a 30-minute period is shown.Shows the course of voltage, current and electrode potentials with a 47 Q resistor in the redox flow battery model of Fig. 4.
[0096] The open-circuit voltage (OCV) is approximately 1.0 V. It drops to a load voltage of 0.42 V with the 47 Q resistor. This resistor initially draws a current of 7.4 mA. The initial potentials of the ROAS relative to a non-housing equipotential bond (NHF) are +0.73 V for the iron salt (cathode) and -0.31 V for the cysteine (anode). These values change with the current draw of the load.
[0097] The battery exhibits good regeneration behavior. After switching off the resistor, the open-circuit voltage (OCV) rises to 0.97 V in 5 minutes and even exceeds the initial value after 10 minutes, as shown in Fig. 7.
[0098] When charging the battery at 1.5 V for 4 minutes in charging cycles 2 and 3, all values increase slightly. The recharge capability of the simulated redox flow battery also demonstrates the reversibility of the electrochemical processes.
[0099] Fig. 7 shows the measured values of the open-circuit voltage and current as well as the electrode potentials during three discharge cycles in the aforementioned system Fe(lli) / Cys.
[0100] Figure 8 shows the measurement results for the charging and discharging behavior of the variant with pomegranate peel extract and Fe(III) solution as anode and cathode materials, based on measurement curves 801-804. The assignment of the measurement curves to the measured quantity is directly derived from the legend of the measurement diagram. The open-circuit voltage (OCV) starts at 0.89 V. The current draw reaches a value of 10.5 mA. The change in the potentials of the anode and cathode materials is small. Between cycles, the battery was charged for 2 minutes at 1.5 V. The values of the discharge cycles are remarkably constant. The measurement was carried out analogously to Figure 6 with regard to voltage, current, and electrode potentials with a resistance of 47 ohms. Figure 9 then shows the measurement results after three discharge cycles for the Fe(III) and pomegranate peel system.
[0101] Figure 10 shows measurement results for the investigation with matcha tea and Fe(ll) solution. The result is similar to that of the variant with pomegranate extract.
[0102] The data confirm that iron(III) salt solution is suitable as a cathode material and cysteine solution, as well as matcha tea and pomegranate peel extract, are suitable as anode materials. None of the aforementioned organic compounds, particularly not in combination with Fe(III) as the corresponding cathode material, have previously been used as active electrolyte materials in batteries. This is a first aspect of the present invention.
[0103] A second aspect of the present invention is the provision of a suitable separator material or a membrane material for a separating membrane to separate the cathode and anode compartments within a battery. To determine a suitable material, the experimental setup of Fig. 11 was used, featuring a separator consisting of a protein compound in the form of collagen, such as that used in the meat industry as sausage casing.
[0104] One condition for suitability as a separation membrane is the material's ability to separate substances while maintaining ion permeability.
[0105] To test different membrane materials, an experimental setup 300 with a galvanic cell 301 was constructed from two PVC tubes 302, which can be joined together in a V-shape after heating. An ion-permeable membrane is fixed between the two tubes. After filling the ROAS (Return of Osmosis with Air) into alkaline or acidic electrolytes, a voltage of 0.74 V is measured using carbon electrodes. This shows that the film fundamentally allows the flow of ions.
[0106] Figure 11 shows a galvanic cell made of a V-shaped PVC tube with a collagen diaphragm as a separating membrane. The diaphragm was still intact on the 7th day of the measurement, i.e., at the end of the measurement series. Thus, the suitability of collagen as a separator or membrane material for use in the edible battery was confirmed. Furthermore, the membrane is uncoated. Thickening the more or less viscous electrode materials is advantageous for improved handling of the present invention.
[0107] Suitable thickening agents include potato starch, activated carbon powder, graphite powder, soot, and mixtures of these species.
[0108] To reduce internal resistance, the use of carbon in various modifications in the respective electrolyte mixtures, i.e., the anode and cathode materials, is advantageous. Activated carbon is particularly preferred here, as it is already used in many areas of the food and pharmaceutical industries.
[0109] For the edible battery version, a capsule material from a pharmacy was chosen as the battery casing. Size 000 is the largest available empty capsule, measuring 26 mm in length and 10 mm in diameter. Cellulose-based capsules are preferred. After extensive testing, combining a size 000 capsule body with a size 00 capsule body proved advantageous. Before filling, the capsule bodies are coated inside and out with liquid beeswax. This prevents deformation of the capsules upon contact with water. The filling quantities can be based on the specific capacitance (Ct) of the materials. This indicates the amount of electrical charge that 1 gram of an electrode material can release or absorb and is calculated as the product of the number of electrons transferred, the Faraday constant, and the molar mass.
[0110] >
[0111]
[0112] For the anode material cysteine, the following results:
[0113]
[0114] For the cathode material Fe2(SO4)3 ■ n H2O (assumption: n = 5) the following results:
[0115] C t (Fe2(5O4)3 • = 54.7 mAhg-
[0116]
[0117] 1 The large difference in capacity can be compensated for with a larger amount of iron sulfate. No precise values can be given for the polyphenol mixtures in the matcha tea and pomegranate extracts. The specific capacities can be estimated using typical polyphenol representatives from the mixtures as examples, assuming a two-electron transfer. The values double for a four-electron transfer.
[0118] mAh / g;
[0119] 116.94 mAh / g
[0120]
[0121] Several variations can be used to fill the capsule body with the thickened electrolyte solutions, including methods with a longitudinal division of the capsule body and with pure beeswax bodies. After many attempts, the variant described in Fig. 18 proved successful in providing an edible battery.
[0122] In tests with the experimental setup shown in Fig. 18, the following proved to be a suitable buffer system for a 20% solution of Fe2(SO4)3: ■ n
[0123]
[0124] A 0.3 M citric acid / citrate buffer with pH = 3.2 is particularly suitable. Percentage values for solutions within the scope of the present invention always refer to wt.%.
[0125] To thicken the anode and cathode material, activated carbon or activated carbon and some starch, especially potato starch, are mixed into a paste-like mass. The addition of activated carbon allows for adjustment or...
[0126] Reduction of the internal resistance values Ri within the battery
[0127] The anode material comprises a 20% cysteine solution in an ammonia / ammonium buffer with a pH of 10.4, which was lowered to 9.02 upon addition of the amphoteric amino acid.
[0128] When using the aforementioned buffer systems, the anode and / or cathode material, compared to other pH buffer systems, advantageously exhibits no or very low proton migration through the membrane, thus preventing pH equalization and consequently a rapid drop in the open-circuit voltage within the battery. This results in improved battery shelf life. All measurements carried out within the scope of the present invention were performed under standard conditions of 25°C and normal pressure, and without inert gas.
[0129] Fig. 15 shows the basic structure of an embodiment of an edible battery 1 according to the invention. Individual elements can also be modified to suit industrial mass production. For example, the electrodes for potential tapping can be made of wire or a sheet of solid material, such as gold, silver, or platinum; however, a flat material composite of a flexible carrier, e.g., made of edible plastic and / or fiber material, preferably cellulose-based, has proven to be more resistant to breakage or tearing.
[0130] The battery 1 comprises a capsule-shaped housing 4, which is formed with a cathode 2 and an anode 3 made of flowable material.
[0131] As previously described, the anode material of anode 3 comprises an alkaline solution containing redox-active organic anions, or the anode material consists of said alkaline solution containing the redox-active organic anions. Preferably, the redox-active organic anions or molecules are selected from naturally occurring, biocompatible polyphenol compounds, carbohydrates, vitamins, organic acids, and / or amino acids.
[0132] The redox-active organic anions selected from ingredients of matcha tea and / or pomegranate peel extract, from gallic acid, cysteine and / or tocopherol are preferred. A natural amino acid, especially cysteine, is particularly preferred.
[0133] L-cysteine is preferably used as the cysteine. The cysteine-containing solution preferably contains at least 5, preferably at least 9 wt.%, and particularly preferably between 10 and 30 wt.% cysteine, especially L-cysteine.
[0134] Preferably, the pH of the anode material is adjusted to a pH between 8 and 11, preferably between 8.5 and 10.5, and particularly preferably to 8.8 and 9.5. A pH buffer is further preferably used to adjust the pH of the anode material within the aforementioned range. This can particularly preferably be an ammonia / ammonium buffer.
[0135] The anode material preferably comprises a thickening agent. This can preferably be a plant-based thickening agent such as starch, preferably potato or corn starch. However, the thickening agent can also consist solely of activated carbon.
[0136] The preferably particulate carbon compound, especially preferably activated carbon powder, is also used in the anode material as a means to reduce the internal resistance.
[0137] To 1-5 ml of the aforementioned anode material, for example 300-700 mg of activated charcoal powder and 200-400 mg of potato starch can be added and stirred into a doughy paste, which is then filled into the anode compartment of the capsule.
[0138] In contrast, the cathode material of cathode 2 comprises, or consists of, an acidic, biocompatible solution containing redox-active inorganic cations. These redox-active inorganic cations are preferably metal ions, and particularly preferably iron(III) ions. Unlike most redox-active organic compounds, these enable a comparatively high potential difference with respect to the corresponding redox pair of the anode.
[0139] The iron(III) compound preferably used in the solution is iron(III) sulfate. However, iron(III) compounds with organic anions can also be used. More preferably, the iron(III)-containing solution contains at least 5 wt.%, preferably at least 9 wt.%, and preferably between 10 and 30 wt.% of the respective iron(III) compound, in particular iron(III) sulfate.
[0140] Preferably, the pH value of the cathode material is adjusted to a pH value below pH=6, preferably between 0.5-5 and particularly preferably between 0.5-3.5.
[0141] A pH buffer is preferably used to adjust the pH value of the cathode material within the aforementioned range. This can preferably be a citric acid / citrate buffer. Preferably, it is a 0.3 M buffer.
[0142] The cathode material preferably comprises a thickening agent for improved handling and to prevent medium leakage from the battery 1. This thickening agent may preferably be activated carbon, a plant-based thickening agent such as starch, preferably potato or corn starch, or mixtures of the two.
[0143] The cathode material also preferably comprises a means for reducing the internal resistance, preferably a particulate carbon compound, particularly preferably activated carbon powder.
[0144] Analogous to the anode material, 300-700 mg of activated carbon powder and 300-500 mg of potato starch can be added to 1-5 ml of the cathode material and stirred into a doughy paste, which is then filled into the cathode chamber.
[0145] The housing 4 comprises two shell-shaped, terminally open capsule bodies 6 and 7. These are connected to each other at an interface 12 in a medium-tight manner. The capsule body is preferably made of a non-conductive plastic or natural material. The capsule material can be a commercially available material such as that used in the pharmaceutical industry. The capsule material can optionally be biodegradable by gastric acid. In this case, the other components of the battery are also degraded or excreted.
[0146] Alternatively, the housing 4 can be made of a capsule material resistant to body fluids, so that the battery 1 is excreted along with other indigestible food components.
[0147] In the embodiment shown in Fig. 15, the capsule bodies 6 and 7 are nested inside one another, forming a closed housing 4. The housing 4 has at least two openings 11. These can preferably be arranged at opposite ends in the housing 4.
[0148] Furthermore, the housing 4 has two compartments 13 and 14 spatially separated from each other by a separating membrane 5. The separating membrane 5 is designed as an ion-permeable and substance-impermeable separating membrane. It can be made of a structural protein-containing material and is preferably designed as a collagen diaphragm.
[0149] The housing 4 has a longitudinal axis A, wherein the separating membrane 5 is preferably arranged substantially perpendicular to the longitudinal axis A. The volume of the first chamber 13 varies with respect to the volume of the second chamber 14 by less than 30%, preferably less than 20%.
[0150] Each of the openings 11 contains a potential tap 10 as an electrically conductive element. Preferably, a potential tap 10 comprises a carrier which is provided on at least one side, preferably both sides, with a conductive layer, preferably a layer of a precious metal. The conductive layer has a higher conductivity than the carrier 8. The carrier layer can preferably be made of a natural organic material or of a edible plastic. To prevent injury, the carrier 8 is preferably designed to be flexible. The carrier can be made of a rubber material or a fibrous material, e.g., a cellulose-based material.
[0151] The material of the conductive layer preferably has a conductivity of more than 1*10 6 S / cm. It is therefore an electrical conductor. The material of the support, on the other hand, has a conductivity of less than 1*10'.8 , preferably of less than 1*10' 18 S / cm. It is therefore an electrical non-conductor.
[0152] The thickness of the conductive layer is preferably greater than 150 nm, and particularly preferably between 180 and 350 nm. Gold, silver, and / or platinum are preferred materials for the conductive layer.
[0153] The battery is constructed such that a potential tap 10 extends into each of compartments 13 and 14, leading from each compartment 13 or 14 through the wall of the housing 4 to a contact zone outside the housing 4 of the battery 1. A component of an electrical device, e.g., a sensor element and / or a component for data transfer with an external device outside the human or animal body, can be connected to the contact zones of both potential taps 10, so that the component is powered by the energy generated by the battery 1. The insertion depth of the potential tap 10 can extend over the entire length of each compartment 13 or 14 along the longitudinal axis of the housing 4 up to the separating membrane 5.
[0154] The transition of the potential tap 10 at the breakthrough and / or the interface between the capsule bodies 6 and 7 can be sealed by a biocompatible sealant, preferably wax, particularly preferably beeswax.
[0155] The penetrations for the potential taps are advantageously designed as perforations at the capsule ends. Naturally, each potential tap is sealed to be at least watertight and ideally also airtight by appropriate sealing measures, e.g., coating or sealant.
[0156] Furthermore, the housing 4 can have an inner coating made of sealing material, in particular wax, especially preferably beeswax, arranged over the entire surface along the capsule walls of the capsule bodies 6 and 7.
[0157] Alternatively or additionally, the housing 4 can have an outer coating made of sealing material, in particular wax, especially preferably beeswax, arranged over the entire surface along the capsule walls of the capsule bodies 6 and 7.
[0158] The capsule walls of the housing enhance its mechanical stability, while the wax layer provides chemical inertness and / or a seal from the outside in and / or from the inside out. However, it is also conceivable to construct the housing entirely from wax. A suitable injection mold can be developed for this purpose.
[0159] Several parameters of the battery described above were determined experimentally. These parameters include capacity (in Ah = stored electrical charge) and power (in W = electrical energy that can be drawn per unit of time). Other characteristic values are the open-circuit voltage and the internal resistance.
[0160] The edible battery according to the invention exhibited internal resistances of 80–200 Ω, mean open-circuit voltages of 1.05 V, and mean discharge voltages of 0.78–0.89 V. Figure 12 shows a charging and discharging curve of a comparative model from the prior art, namely the edible battery developed in 2023 with a current draw of 240 pA.
[0161] The prior art comparison model, as can be seen in Fig. 12, delivers a current of 240 pA at an average voltage of 0.65 V for 2 minutes. Its capacity is 7 pAh.
[0162] The inventive variant shown in Fig. 15 delivered an average voltage of 0.89 V at a current draw of 500 pA over 3 h, as can be seen from the measurement curve 601 in Fig. 13. This results in a capacity of 1.5 mAh and means that the battery according to the invention has more than 200 times the capacity of the prior art comparison model shown in Fig. 12 during the first discharge process.
[0163] This value was confirmed by repeated measurements with additional batteries of the same design. The average voltages ranged from 0.89 to 0.78 V at a current draw of 500 pA over 3 hours. The discharge curve also shows how the battery recovers after 180 minutes without a load.
[0164] When charging with a 500 pA charging current according to measurement curve 602, the voltage rises from 0.82 V to 1.6 V in 90 minutes. Afterwards, there is the voltage drop often observed in rechargeable batteries after a full charge, here to a stable 1.29 V. This exceeds the initial open-circuit voltage by 19%.
[0165] Here the second discharge begins with a constant current draw of 500 pA. Measurement curve 603 remains at a high level for an extended period. It reaches 0.78 V after 1 hour, 0.74 V after 2 hours, 0.66 V after 3 hours, and 0.55 V after 4 hours. Thus, during the second discharge process, the battery retains a capacity of 2 mAh at a current draw of 500 pA and an average voltage of 0.8 V.
[0166] The measurements were performed using the GW Instek MDO-2204EX digital oscilloscope.
[0167] The energy potential of the battery according to the invention is unlimited, as demonstrated by a measurement according to Fig. 14, in which an internal resistance of 80 Ω was used for 7 hours and 15 minutes at a current draw of 500 pA. The measurement yielded an average voltage of 0.9 V and a capacity of 3.625 mAh. The residual voltage after 7 hours was 0.8 V. The battery according to the invention could be charged and discharged several times over two days with similarly good results.
[0168] Possible discrepancies between the measured values of individual batteries may be due to the final insertion of the electrodes during the assembly process.
[0169] For reasons of repeatable performance, the potential taps 10 from a coated carrier 9 were replaced by equally sized, robust silver sheets made of 935 silver. After the battery is filled, they are inserted into slots at the two "battery terminals".
[0170] Any deviations can be traced back to positional deviations of the potential taps, which are usually eliminated in standardized manufacturing processes for mass production.
[0171] Furthermore, repeated measurements of several batteries show a high degree of agreement with regard to the capacity of the first discharge and the rechargeability. This refers to the validation on the day the batteries were filled or made available. The open-circuit voltage begins to decrease as early as the following day. The capacity of the battery according to the invention is consistently far higher than that of the reference battery in Fig. 12 for all batteries produced in the measurement series.
[0172] On the third day, a drop in the open-circuit voltage of up to 50% was observed, which could be corrected by recharging. The open-circuit voltage can thus be maintained for several hours, so that, for example, when used in a diagnostic device, the power storage unit exhibits nearly constant values from oral ingestion until reaching the point of care, e.g., an area in the intestinal tract to be analyzed, unlike the reference battery.
[0173] Preservation of the electrode materials in glass capsules with a similar design resulted in preservation for over a week and beyond. This means that the battery components are also storable and transportable and can be assembled immediately before use, for example, in a pharmacy or by trained medical personnel in a specialist's office, similar to the daily preparation of a medication. The ingredients of the battery cell shown in Fig. 15 are listed in Fig. 16. These are exclusively foodstuffs and EU-approved food additives that can be consumed by humans in larger quantities (> 100 mg / day) without harm. The latter is regulated by the Acceptable Daily Intakes (ADI) established by the European Food Safety Authority (EFSA). The only exception is the iron(III) preparation, the safe intake of which has already been discussed.The battery, which is to be ingested by humans, weighs less than 5 g, preferably less than 3.5 g, preferably between 1.0 and 3.0 g, with a total volume, excluding the potential taps 10, of less than 5000 mm³. 3 , preferably less than 4000 mm 3 and especially preferably between 1000-3500 mm 3 .
[0174] Furthermore, the battery according to the invention was subjected to a cyclic voltammetric investigation. This allows for a thorough evaluation of the electrode processes and provides insights into their reversibility and the quality of rechargeability. As can be seen from the measurement curves in Fig. 17, both the Fe(I1L) / Fe(I1I) and the cysteine / cystine redox systems are reversible. The combination of both redox systems can, in turn, be classified as "quasi-reversible." This can be deduced from the differences AEp of the oxidation peaks Epa and the reduction peaks Epk. "Quasi-reversible" means fundamental rechargeability, albeit with a certain inhibition of charge transfer and the electrode reaction.
[0175] In contrast, cyclic voltammetric investigations of matcha tea and pomegranate extracts in 0.1 N NaOH revealed exclusively oxidation peaks. This indicates that no reversible redox reactions are possible for these systems.
[0176] The following section describes in more detail a method for producing an edible battery according to the invention.
[0177] In a first step 401, the preparation of current collectors or the respective potential tap takes place.
[0178] In a first step (401-1), a support 8 made of a carrier material is prepared. A container, e.g., a Petri dish, is filled with a solution of ethylcellulose, abbreviated EC, e.g., 600 mg in 30 ml of ethanol. The alcohol is then evaporated in a drying oven, preferably at 60°C. The result is a thin, transparent ethylcellulose film.
[0179] In a second step 401-2, the electrodes for the potential tap 10 are prepared. For this purpose, a sheet of tissue paper with a square of gold leaf is placed centrally on a cobalt glass plate. A square of EC foil is then cut out. Adhesive tape is applied to the glass plate. The EC foil is coated with ethanol and, together with the glass plate, is placed onto the gold leaf to form the gold layer 9. The preferred thickness of the gold leaf is preferably more than 150 nm, particularly preferably between 180 and 350 nm. After drying, the gold-coated foil is separated from the glass plate of the prepared arrangement. The gold leaf-EC composite can then be cut into strips.
[0180] The EC foil can then be coated with gold leaf on the opposite side as a gold layer 9 in an analogous manner. The result is an electrode coated with gold leaf on both sides for potential tapping 10.
[0181] In a second step 402, the capsule-shaped housing 4 is prepared. Using a hot needle, a slit-shaped opening 11 is worked into the housing 5 at the ends of a 000 and 00 capsule body 6 and 7. The capsule bodies 6 and 7 are hemispherical, with a feed opening. The capsule body is then immersed, if necessary several times, in a wax bath, preferably beeswax, so that the respective slit-shaped opening is sealed with wax on both the inside and outside. The smaller capsule body 7 is then shortened, for example, by a length of 3 mm using the cutting disc of a Dremel multi-tool.
[0182] In a third step 403, the capsule is filled by filling the smaller capsule body 7 with a thickened iron sulfate mixture. Filling can be carried out, in particular, up to the top edge of the capsule body 7. Subsequently, the separating membrane 5 is placed on top. The larger 000 capsule half 6 is then filled with a thickened cysteine mixture.
[0183] In a fourth step 404, the housing 4 is formed. This can preferably be done by inserting the two shell-shaped capsule bodies 6 and 7 into one another and by sealing 405 the entire housing, particularly at the interfaces of the capsule bodies. The sealing can be carried out by immersion in the aforementioned wax bath.
[0184] The electrodes for the potential tap 10 can then be inserted through the terminal slot-shaped openings 11 in step 406. For this purpose, the openings are exposed, for example, with a scalpel, and the gold-coated electrodes can be inserted into the housing 5 through the respective opening, preferably up to the separating membrane 5. The openings 11 around the electrodes 10 can then be sealed in step 407, for example, by applying wax. A wax modeling tool with a heated tip can be used as an assembly aid for this purpose.
[0185] For this purpose, the aforementioned electrodes, strips of gold leaf, can be inserted into the capsule ends with the openings into the anode and cathode compartment as current collectors.
[0186] These electrodes, particularly in the form of gold leaf strips, can advantageously be laminated with an edible ethyl cellulose film. The insertion slots will be hermetically sealed with a previously described water-repellent coating material.
[0187] •
[0188] The previously described pasty filling of the larger capsule half, which serves as the cathode space, is covered with a cut piece of collagen film so that it rests on the pasty filling. The two filled halves are then fitted together so that both fillings touch the separator, and the separator is clamped between the two capsule halves. The excess collagen film is trimmed away, and the capsule is sealed at the seam between its two halves with the water-repellent coating material.
[0189] •
[0190] An edible battery according to the invention can then preferably have internal resistances between 50 and 300 Ω and also preferably supply open-circuit voltages between 0.9 and 1.06 V.
[0191] With a current draw of 500 pA over a period of 3-7 hours and an average discharge voltage of 0.7-0.9 V, it can preferably achieve capacities of 1500-3625 pAh. Reference symbol
[0192] 101 Standard hydrogen electrode NHE 102 Petri dish
[0193] 103 partition walls
[0194] 104, 105, 106 separate areas
[0195] 107 Platinum wire
[0196] 108 Control and / or evaluation unit
[0197] 201 beaker
[0198] 202 Electrolyte filling
[0199] 203 Clay pot
[0200] 204 Anode material
[0201] 205 cathode materials
[0202] 206 Magnetic stir bar
[0203] 207 Magnetic stirrer
[0204] 208 Graphite felt electrode
[0205] 209 Structure
[0206] 210 measuring unit
[0207] 211 Resistance
[0208] 300 Experimental setup
[0209] 301 galvanic cell
[0210] 302 PVC hose
[0211] 401 Preparation of the potential tap 401-1 Provision of a carrier 401-2 Provision of the electrodes 402 Preparation of the housing
[0212] 403 Filling the housing
[0213] 404 Design of the housing
[0214] 405 Sealing the housing
[0215] 406 Inserting the potential taps 407 Sealing the potential taps
[0216] 601-603 Measurement curve
[0217] 701-704 Measurement curve
[0218] 801-804 Measurement curve 1 Battery
[0219] 2 Cathode
[0220] 3 Anode
[0221] 4 cases
[0222] 5 Separating membrane 6 Capsule body 7 Capsule body 8 Carrier
[0223] 9 Gold layer 10 Potential tap 11 Breakthrough 12 Interface 13 Space
[0224] Room 14
[0225] Longitudinal axis
Claims
Claims 1. Edible battery (1) for insertion, in particular for oral ingestion, into a human or animal body, wherein the battery (1) has a housing (4) with at least two compartments (13, 14) separated from each other by an ion-permeable separating membrane (5), wherein a first of the compartments (13, 14) has a cathode (2) and a second of the compartments (13, 14) has an anode (3), wherein a potential tap (10) is arranged at least partially in each of the compartments (13, 14) for drawing a potential to an area outside the housing (4), wherein the edible battery (1) is composed exclusively of biocompatible materials, in particular suitable for human and animal consumption, characterized in that the anode (3) has a biocompatible anode material, in particular a biocompatible solution, with redox-active organic anions or molecules and that the cathode (2) has a biocompatible cathode material,in particular a biocompatible solution, containing redox-active inorganic cations and / or cations of an organic acid with polyphenolic character.
2. Edible battery according to claim 1, characterized in that the biocompatible solution of the anode (3), in particular of the anode material, has an alkaline pH value and is preferably formed from a flowable material.
3. Edible battery according to claim 1 or 2, characterized in that the redox-active organic molecules or anions are formed from one or more naturally occurring, biocompatible redox-active polyphenol compounds, redox-active carbohydrates, redox-active vitamins, organic acids, in particular fruit acids, and / or from amino acids.
4. Edible battery according to any one of the preceding claims, characterized in that the redox-active organic molecules or anions are formed from ingredients of matcha tea, pomegranate peel extract, gallic acid, cysteine, in particular L-cysteine, ascorbic acid and / or tocopherol.
5. Edible battery according to claim 4, characterized in that the biocompatible solution of the anode (3), in particular of the anode material, comprises at least 5 wt.%, preferably at least 9 wt.%, particularly preferably between 10-30 wt.% of a natural amino acid, preferably cysteine, in particular L-cysteine.
6. Edible battery according to one of the preceding claims, characterized in that the pH value of the biocompatible solution of the anode (3), in particular of the anode material, is adjusted to a pH value between 8-11, preferably between 8.5-10.5 and particularly preferably to 8, 8-9, 5.
7. Edible battery according to one of the preceding claims, characterized in that the biocompatible solution of the anode (3), in particular of the anode material, comprises a pH buffer, preferably an ammonia / ammonium buffer.
8. Edible battery according to one of the preceding claims, characterized in that the biocompatible solution of the cathode (2), in particular of the cathode material, is formed as an acidic solution with a pH value less than pH=7 from a flowable material.
9. Edible battery according to one of the preceding claims, characterized in that the redox-active inorganic cations are formed as metal ions, preferably as iron ions and particularly preferably as iron(III) ions.
10. Edible battery according to one of the preceding claims, characterized in that the compound for providing the iron ions, in particular the iron(III) ions in solution, is formed as iron(III) sulfate or as iron(III) compounds with organic anions.
11. Edible battery according to any one of the preceding claims, characterized in that the compound for providing the iron ions, in particular the iron(III) ions, is contained in the solution to at least 5 wt.%, preferably 9 wt.%, and particularly preferably between 10 and 30 wt.%.
12. Edible battery according to any one of the preceding claims, characterized in that the pH value of the biocompatible solution of the cathode (2), in particular of the cathode material, is adjusted to a pH value below pH 6, preferably between 0.5 and 5, and particularly preferably between 0.5 and 3.
5.
13. Edible battery according to one of the preceding claims, characterized in that the biocompatible solution of the cathode (2) comprises a pH buffer for adjusting the pH value, preferably a citric acid citrate buffer, particularly preferably a 0.3m buffer.
14. Edible battery according to one of the preceding claims, characterized in that the separating membrane (5) is formed from a protein-based, in particular structural protein-containing, material and is preferably designed as a collagen diaphragm.
15. Edible battery according to one of the preceding claims, characterized in that the housing (4) has a sealing material, preferably as a water-repellent coating material, or is formed from a sealing material, wherein the sealing material is a wax and / or rubber, preferably a beeswax and / or a natural rubber.
16. Edible battery according to one of the preceding claims, characterized in that the casing (4) of the battery (1) has an external volume of less than 5000 mm³ 3 , preferably less than 4000 mm 3 , and especially preferably between 1000-3500 mm 3 exhibits.
17. Edible battery according to one of the preceding claims, characterized in that the housing (4) is designed as a medium-tight sealed capsule, preferably with two shell-shaped capsule bodies which are connected to each other along an interface in a medium-tight manner, preferably by the sealing material according to claim 15.
18. Edible battery according to any one of the preceding claims, characterized in that the capsule is predominantly formed from one or more biopolymers, preferably from at least one biopolymer based on proteins and / or carbohydrates.
19. Edible battery according to any one of the preceding claims, characterized in that the capsule or a coating applied thereto is predominantly formed, by more than 50% by weight, from gelatin, cellulose, chitin, chitosan and / or from a material based on one or more of these substances.
20. Edible battery according to one of the preceding claims, characterized in that the biocompatible solution of the anode (3) and / or the cathode (2), in particular of the anode and / or cathode material, comprises a thickening agent.
21. Edible battery according to any of the preceding claims, characterized in that the thickening agent is a plant-based thickening agent, preferably starch, particularly preferably potato or corn starch, or a carbon compound, preferably activated carbon, or a mixture of the plant-based thickening agent and the carbon compound.
22. Edible battery according to one of the preceding claims, characterized in that the biocompatible solution of the anode (3) and / or the cathode (2), in particular of the anode and / or cathode material, comprises a means for reducing the internal resistance, preferably a particulate carbon compound, particularly preferably activated carbon powder.
23. Edible battery according to one of the preceding claims, characterized in that the potential tap (10) has a carrier (8) consisting of a flexible carrier material, preferably a flexible carrier (8).
24. Edible battery according to one of the preceding claims, characterized in that the carrier (8) is provided on two opposite sides with a material having a higher electrical conductivity than the carrier (8) itself.
25. Edible battery according to any one of the preceding claims, characterized in that the carrier (8) is designed as a non-conductor and the material layer (9) arranged on the carrier, preferably on both sides, is designed as an electrical conductor, preferably made of a precious metal, particularly preferably of gold, silver or platinum.
26. Edible battery according to any one of the preceding claims, characterized in that the carrier (8) has a precious metal layer (9) and a foil layer made of edible material, preferably of ethylcellulose laminate foil, arranged on the outside of the precious metal layer.
27. Edible battery according to one of the preceding claims, characterized in that all ingredients of the battery (1) are approved as food and / or as ingredients for food supplements.
28. Method for manufacturing the battery (1) according to one of the preceding claims, characterized by the following steps: a) Providing (401) two potential taps (10), preferably in the form of two current collectors, two shell-shaped capsule bodies (6, 7) and two thickened biocompatible redox-active solutions as anode and cathode material; b) Filling (403) the capsule bodies (6, 7) of a housing (4) with a solution each and joining the capsule bodies (6, 7) by inserting a separating membrane (5); c) Inserting the potential taps (10) through the housing wall of the housing (4).
29. Use of an edible battery (1) according to any of the preceding claims for powering an orally ingested electrical device, in particular a medical diagnostic device, preferably in the intended ingested state.
30. Use of an edible battery (1) according to one of the preceding claims for supplying energy to an electrical device wherein no charging process of the battery (1) takes place during its manufacture until its intended use.
31. Use according to one of the preceding claims, characterized in that the electrical device is supplied by the edible battery for a period of at least 3h with a capacity of 1500 - 3625 pAh and a mean discharge voltage of 0.7 - 0.9 V.