Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M6/00—Primary cells; Manufacture thereof
  • H01M6/04—Cells with aqueous electrolyte
  • H01M6/06—Dry cells, i.e. cells wherein the electrolyte is rendered non-fluid
  • H01M6/12—Dry cells, i.e. cells wherein the electrolyte is rendered non-fluid with flat electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M6/00—Primary cells; Manufacture thereof
  • H01M6/40—Printed batteries, e.g. thin film batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese

Definitions

• the present invention relates to a battery having a flat positive and a flat negative electrode, which, separated by a gap, arranged side by side on a flat substrate and connected to each other via an ion-conductive electrolyte.
• Batteries are known in various embodiments.
• printed batteries in which at least some, preferably all functional parts, in particular the electrodes and arrester structures, are formed on a corresponding substrate by pressure.
• the batteries described have electrodes which are arranged side by side on a substrate.
• the functional parts of the battery are arranged substantially one above the other only in three planes (a conductor plane, an electrode plane and an electrolyte plane).
• the advantage of the comparatively thin construction is bought at a high price. Since the ions not only have to walk through a thin separator plane in operation, as is the case with electrodes in the form of a stape, but instead have to travel very long distances over the electrolyte layer, the internal resistance of a battery with electrodes arranged parallel next to one another rises sharply during operation , At the same time, of course, the current-carrying capacity also drops.
• the battery according to the invention is characterized in that at least the thickness of one of the two electrodes, preferably the thickness of both electrodes, is in a certain ratio to the minimum width of the gap.
• the quotient of the thickness and the minimum width is always between 1:10 and 10: 1, preferably between 0.5: 1 and 5: 1, in particular between 0.5: 1 and 2: 1, particularly preferably between batteries according to the invention 1: 1 and 2: 1.
• both the quotient of the thickness of the positive electrode and the minimum gap width and the quotient of the thickness of the negative electrode and the minimum gap width are within these ranges.
• the internal resistance of batteries with electrodes arranged side by side on a flat substrate can be significantly reduced by optimizing the ratio of electrode thicknesses and gap widths as indicated. In part, an inner resistance reduced by more than a third was observed, which was not expected a priori.
• the current carrying capacity of the batteries according to the invention is greatly improved compared to that of comparable conventional batteries.
• the surfaces that occupy the electrodes of a battery according to the invention on the substrate are each defined by a circumferential boundary line. In each of the electrodes, at least a part of the boundary line faces one or the corresponding oppositely poled electrode.
• the oppositely poled electrode “facing parts" of the boundary line is to be understood in particular the parts in which each point of the line can be connected by a straight line, in particular a straight line perpendicular to the boundary line at this point, with the boundary line of an electrode of opposite polarity without losing one of the touch or cut boundaries at more than one point. It is preferred that these parts of the boundary lines also define the gap between the electrodes. More precisely, preferably, the gap separating the sheet positive and sheet negative electrodes is defined as the largest possible non-electrode material covered area on the substrate that can be trapped by straight lines between the boundary lines forming a point on the substrate Limit line connecting one electrode to a point on the boundary line of the other electrode, without touching or cutting one of the boundary lines at more than one point.
• More than one circumferential boundary line would be e.g. in concentric arrangement of a plurality of annular or circular electrodes conceivable. In such an arrangement, it would then also be possible for the boundary line of an electrode to be completely, ie not only partially, facing the associated oppositely poled electrode.
• the mentioned minimum width of the gap should be understood to mean the gap width at the location of the shortest possible ion path between the two electrodes.
• the minimum width of the gap thus corresponds to the smallest distance between the boundary lines defining the electrodes.
• the electrodes of a battery according to the invention each have a substantially uniform thickness over their entire surface, which, however, may vary slightly under certain circumstances, possibly due to the production process.
• the electrodes are preferably cut once longitudinally or transversely in such a way that a maximum cutting length is obtained (in the case of a rectangular electrode, for example, the cut is preferably carried out as a diagonal). The cut is then split into two equally long sections. divided, in the middle of each of which the measurement of the electrode thickness. The values obtained are then averaged.
• the gap between the electrodes preferably has a substantially uniform gap width.
• the shortest possible ionic path between the two electrodes in the region of the gap is preferably always the same over at least 95% of the length of the gap, in particular over the entire length of the gap.
• the gap width along the gap does not vary by more than 25%, in particular less than 10%, particularly preferably less than 5% (in each case based on the minimum gap width).
• the above-defined minimum width then not only exists between two points on the boundary lines of the electrodes, but rather the electrodes preferably have a substantially constant distance from one another along the mutually facing parts of the gap-forming boundary lines.
• the usual gap widths between 10 ⁇ and 2 mm. Within this range gap widths between 50 ⁇ and 1 mm, more preferably between 50 ⁇ and 500 ⁇ , particularly preferred.
• the positive and the negative electrode of a battery according to the invention have substantially the same thickness.
• the quotient of the thickness of the positive electrode and the minimum gap width is thus preferably identical to the quotient of the thickness of the negative electrode and the minimum gap width.
• Preferred electrode thicknesses for the positive and the negative electrode are preferably in the range between 10 ⁇ m and 500 ⁇ m, more preferably between 10 ⁇ m and 250 ⁇ m, in particular between 50 ⁇ m and 150 ⁇ m.
• materials for the negative electrodes of batteries have a higher energy density than comparable materials for the positive electrode. rode. It is accordingly preferred that the positive electrode occupy a larger area on the substrate than the negative electrode. Of course, this applies in particular if the positive electrode and the negative electrode have comparable or the same thicknesses.
• the electrodes are formed at least in partial regions, preferably completely, as strips, in particular as rectangular or band-shaped strips.
• the strips preferably have a substantially uniform width substantially over their entire length.
• the electrodes may each comprise a plurality of strip-shaped sections, which are arranged parallel to one another. These may e.g. formed on a common transverse web which is oriented orthogonally to the strips and is preferably likewise strip-shaped or band-shaped, so that a "comb-like" configuration results in its entirety
• Two electrodes formed in this way can of course be intermeshed on a substrate without problems. Assign (of course, assuming coordinated dimensions), namely by parallel arrangement of the transverse webs to each other, then in each case between two parallel strips of an electrode, a strip of the electrode with opposite polarity comes to rest.
• the advantage of such an embodiment of the electrodes is that the length of the gap between the electrodes increases greatly in relation to the area of the electrodes, which in turn reduces the distance on average that the ions have to travel from one electrode to another. Or more precisely, it can be very advantageous if the ratio of the length of the part of the boundary line of an electrode facing the corresponding oppositely poled electrode to the total length of the boundary line is as large as possible. In combination with the optimized ratio of electrode thickness and gap width can be achieved in view of the current carrying capacity of the battery drastic improvements.
• the quotient of the length of the corresponding oppositely poled electrode facing part of the boundary line of an electrode to the total length of the boundary line is above 0.4. It is preferably more than 0.5, more preferably it is greater than 0.75, in particular greater than 0.9. In particularly preferred embodiments of a battery according to the invention, there is also an optimum ratio for the ratio of the width of the strips to the width of the gap between the electrodes, in particular between the strip-shaped electrodes. Preferably, the quotient of the width of the strips to the width of the gap between the electrodes is between 0.5: 1 and 20: 1. Within this range, values between 0.5: 1 and 10: 1 are more preferred.
• Usual strip widths preferably move in the range between 0.05 mm and 10 mm, in particular between 0.05 mm and 2 mm.
• the ratio of the length of the strips to their width is preferably in the range between 2: 1 and 10,000: 1, in particular between 10: 1 and 1: 1000: 1. In other words, preferably the length of the strips is between factor two and factor ten thousand above their width.
• a battery according to the invention may, in preferred embodiments, comprise more than one positive or more than one negative electrode, in particularly preferred embodiments also more than one positive and more than one negative electrode.
• the above-defined ratios of electrode thickness to the minimum width of the gap and the length of the part of the boundary line of an electrode facing the corresponding oppositely poled electrode apply to the total length of the boundary line for all these electrodes.
• a plurality of strip-shaped positive and negative electrodes are arranged side by side on a substrate, in particular in a parallel arrangement to each other.
• An alternating arrangement is preferred, so that a positive electrode is at least always adjacent to a negative electrode and vice versa.
• the gap width between the adjacent electrodes is preferably substantially constant.
• two strip-shaped negative electrodes and one strip-shaped positive electrode may be arranged in parallel with each other on the substrate with the positive electrode disposed between the negative electrode strips and the gap having a substantially uniform width on both sides of the positive electrode over its entire length.
• these electrodes are connected to one another via conductor tracks.
• Such interconnects serve as arresters / collectors and are expediently preferably arranged between the planar substrate and the electrodes.
• Such printed conductors can be realized, for example, by pressure.
• conductor tracks can be applied by sputtering or galvanically on the substrate.
• the electrodes are connected to one another via an electrolyte layer.
• Suitable electrolytes are known to the person skilled in the art.
• a gel-type electrolyte is used as the ion-conductive electrolyte. If necessary, this can also be applied by pressure to the substrate. Ideally, it should at least partially cover the electrodes to provide sufficient conductivity.
• the electrolyte covers the positive and negative electrodes on the substrate completely, may even extend beyond the corresponding boundary lines of the electrodes.
• the maximum thickness of the electrolyte layer (measured from the substrate) preferably moves in the range between 10 ⁇ and 500 ⁇ , in particular between 50 ⁇ and 500 ⁇ .
• the electrodes of a battery according to the invention are printed on the substrate in preferred embodiments.
• the battery according to the invention is thus preferably a printed battery in which at least some, preferably all functional parts, in particular the electrodes, the absorber and / or the electrolyte, are formed on a corresponding substrate by pressure.
• Common electrode materials which are present as a printable paste are known to the person skilled in the art. These can be applied comparatively easily by standard methods, for example by means of a screen printing method, to corresponding substrates, in particular as thin layers having a substantially uniform thickness, in accordance with the above statements.
• the present invention is applicable to a wide variety of electrochemical systems.
• the battery of the invention is e.g. a zinc-brownstone battery or a nickel-metal hydride battery.
• the battery according to the invention may accordingly be a primary battery and a secondary battery.
• the substrate of a battery according to the invention may be, for example, a plastic film. In principle, however, all electrically non-conductive materials come into question, such. As well as paper or wood.
• a battery according to the invention may comprise a second substrate, in particular as a cover layer, which is preferably arranged above the plane of the electrolyte and at least partially covers it and the electrodes.
• This cover layer which may be, for example, a plastic film, on the one hand has a protective function for the electrolyte and the electrodes.
• the cover layer of the battery according to the invention gives overall improved mechanical stability.
• the first and second substrates may be made of the same material.
• the surfaces of the electrodes on the substrate are each defined by a circumferential boundary line, wherein in each of the two electrodes at least part of the boundary line faces at least one corresponding, oppositely poled electrode.
• the battery according to the invention when the battery according to the invention is present as a printed battery, it is preferred that at least in one of the two electrodes, preferably in both electrodes, at least this part of the boundary line has a non-linear course. This applies in particular when the electrodes of a battery according to the invention or at least parts of the electrodes are in the form of strips, as described above.
• “Non-linear curve" is to be understood as meaning that the part of the boundary line (as a whole) is not a straight line However, he may well have straight sections.
• At least one, preferably both electrodes at least part of the boundary line preferably has a rectangular, triangular, wave, spiral or sawtooth-like course. Particularly preferably, these parts engage in one another such that the resulting gap between the electrodes has a substantially uniform gap width.
• the prerequisite for the meshing is, of course, that the respective dimensions of the corresponding electrodes are matched to one another.
• the electrodes or at least parts of the electrodes in particular the parts of the electrodes, which are in the form of strips, corresponding to a rectangular, triangular, wavy, spiral or sawtooth-like course.
• the electrodes preferably have one of the courses mentioned in their entirety.
• Embodiments of a battery according to the invention (cross-section, schematic representation)
• Fig. 5 embodiments of strip-shaped electrodes of a battery according to the invention with triangular, sawtooth, wave and spiral geometry (schematic representation).
• 6 shows a further embodiment of the electrodes of a battery according to the invention with a comb-shaped pattern (schematic representation)
• the positive electrode 101 is shown in white, the negative electrode 101 in black.
• the surfaces of the electrodes are each defined by a circumferential boundary line.
• the electrodes are each rectangular in shape and separated by a gap 103.
• the gap is the largest possible area not covered by electrode material, which can be enclosed between the boundary lines of the electrodes by straight lines connecting a point on the boundary line of one electrode to a point on the boundary line of the other electrode without touching or cutting one of the boundary lines at more than one point. This area is hatched.
• the electrodes are connected via an electrolyte layer which completely covers the electrodes (not shown).
• the ions initially migrate in the immediate vicinity of the gap from one electrode to the other. This results in a charge gradient within the electrodes.
• the shortest ion path from the point 104 on the boundary line of the positive electrode 101 to the negative electrode 102 corresponds to the sum of the width b k of the positive electrode and the gap width s.
• the internal resistance of the battery increases strongly.
• Fig. 2 shows an embodiment of the electrodes 201 and 202 of a battery according to the invention with comb-shaped pattern (schematic representation).
• the electrodes 201 and 202 each include a plurality strip-shaped portions 203a to 203d and 204a to 204d, which are arranged parallel to each other. These are each formed on common, orthogonal aligned to the strip, also strip-shaped or band-shaped transverse webs 205 and 206 integrally formed. In its entirety, this results in a "comb-like" configuration, in which the electrodes are arranged “intermeshing" on the substrate.
• the transverse webs 205 and 206 are arranged parallel to one another, wherein in each case a strip of the electrode with opposite polarity comes to rest between two parallel strips of an electrode.
• the electrodes 201 and 202 are separated by a gap 207. This is defined by the mutually facing parts of the boundary lines of the electrodes 201 and 202.
• the gap width is substantially constant over the entire length of the gap.
• the gap itself has in its entirety, like the boundary lines defining it, a rectangular and thus a non-linear course, but it comprises a plurality of linear sections (5 sections of length I, 4 sections of lengths b a and bk).
• the advantage of such an embodiment of the electrodes lies in the fact that the ratio of the length of the gap 207 between the electrodes 201 and 202 to the surface of the electrodes is greatly increased, which in turn causes the distance to decrease on average which have to travel the ions from one electrode to the other.
• Positive and negative electrodes each have the same thickness. However, the positive electrodes occupy more area than the negative ones. Although the strip-shaped sections 203a to 203d and 204a to 204d all have the same length, they differ in their width (b a ⁇ bk). The ratio of the thickness of the two electrodes 201 and 202 to the width of the gap is between 1:10 and 10: 1.
• FIG. 3 shows an embodiment of the electrodes of a battery according to the invention in a strip-shaped configuration (schematic illustration). Position).
• four positive electrodes 301a to 301d and four negative electrodes 302a to 302d are arranged parallel to one another and in alternating sequence (alternately positive and negative). Electrodes of the same polarity are each connected via the Abieiter 303 and 304. Between adjacent electrodes there is in each case a gap 305 with a constant gap width s. Positive and negative electrodes each have the same thickness. The ratio of the thickness of the electrodes to the width of the gap s is between 1:10 and 10: 1. The positive electrodes occupy more area than the negative ones.
• strip-shaped sections 301a to 301d and 302a to 302d all have the same length, they differ in their width (b a ⁇ b k ). In this embodiment too, it is ensured that the ratio of the total length of the gap 305 between the electrodes to the surface of the electrodes is greatly increased.
• Fig. 4 shows two embodiments A and B of a battery according to the invention (cross-section, schematic representation).
• the battery according to Embodiment A includes the positive electrodes 401a to 401c and the negative electrodes 402a to 402c.
• the battery according to Embodiment B includes the positive electrodes 403a to 403e and the negative electrodes 404a to 404e.
• the electrodes are arranged on the substrates 405 and 406 as shown in Fig. 3, ie in the form of mutually parallel strips. Between the electrodes there are gaps with the constant gap width s.
• the electrodes are covered by an electrolyte 407 and 408, which also fills the gaps between the electrodes.
• the electrodes 401 ac and 402a-c differ in their thickness from the electrodes 403a-e and 404a-e.
• the thickness of the electrodes approximately corresponds to the gap width s, while in embodiment B the electrodes are thicker than the gap by a factor of 2.
• Batteries in embodiment B generally have a higher current carrying capacity than batteries in embodiment A, as well as a comparatively lower internal resistance during operation. This is particularly due to the fact that in embodiment B, the majority of the ions can migrate across the electrolyte in the gap between the electrodes.
• FIG. 5 shows possible embodiments of the electrodes of a battery according to the invention.
• A triangular
• B sawtooth
• C wave
• D spiral
• Fig. 6 shows a further embodiment of the electrodes of a battery according to the invention in comb-shaped pattern (schematic representation). Shown are a positive (white) and a negative electrode 601 and 602. Separated are the electrodes through the gap 603.
• the horizontally oriented electrode strips and also the vertical webs have no uniform width, instead, they are wedge-shaped or trapezoidal in shape. This can also have a positive effect on the internal resistance.
• a plastic film was provided as a substrate and another plastic film as a cover film.
• plastic films with low gas and water vapor diffusion rates are generally used.
• films made of PET, PP or PE Particularly suitable films are described in International Patent Application Serial No. WO / 2009/135621. If it is intended to heat-seal these films together later, the provided base films can additionally be laminated with a low-melting additional material. Suitable hot melt adhesives are known to the person skilled in the art.
• a dissipator structure was then first applied to the substrate.
• a silver-containing conductive ink was printed.
• conductive adhesives based on nickel or graphite can be used, which can also be printed.
• the electrode material for the positive electrode was printed on the corresponding collector / arrester.
• the printing was carried out by means of a screen printing machine.
• a paste consisting of an electroactive material such as MnO 2 (308mAh / g), a binder, a conductive material (graphite or carbon black) and a solvent was used.
• the negative electrode was prepared.
• a paste consisting of an electroactive material such as Zn powder (820 mAh / g), a binder and a solvent was used.
• the electrodes were printed in uniform strips of 30 mm in length, the positive in a width of 0.23 mm, the negative in a width of 0.07 mm.
• the gap between the electrodes had a width of 0.1 mm.
• the electrodes (positive and negative) had a thickness of about 190 ⁇ .
• the electrolyte was applied in a further process step.
• the electrolyte is preferably a aqueous (KOH, ZnCl 2 ) or organic solution of conductive salts, which provide the ions for the flow of current.
• the application of the electrolyte was likewise carried out by a printing process.
• the electrolyte completely covered the electrodes shown in FIG. 4B.
• the gaps between the electrodes were completely filled with electrolyte, over the electrodes the thickness of the electrolyte layer was 10 ⁇ m.
• the single cell thus produced was then covered with the further plastic film, i. H. closed in the manner of a housing. This was done by means of a heat sealing method.
• the resulting battery had an initial internal resistance of 2 ohms. During operation, this resistance increased up to 13 ohms.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Battery Electrode And Active Subsutance (AREA)
• Secondary Cells (AREA)
• Primary Cells (AREA)
• Connection Of Batteries Or Terminals (AREA)

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• 2010
  • 2010-10-05 CN CN2010800557782A patent/CN102668202A/zh active Pending
  • 2010-10-05 US US13/499,812 patent/US20120202100A1/en not_active Abandoned
  • 2010-10-05 EP EP10760364A patent/EP2486617A1/de not_active Withdrawn
  • 2010-10-05 WO PCT/EP2010/064801 patent/WO2011042418A1/de active Application Filing
  • 2010-10-05 KR KR1020127010371A patent/KR20120093894A/ko not_active Application Discontinuation
  • 2010-10-05 JP JP2012532565A patent/JP2013507727A/ja active Pending

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