DE10313005B4 - Backup battery and method for its manufacture - Google Patents

Abstract

reserve battery with an anode and a cathode as electrodes of 5 to 500 microns thickness on a Substrate and a space for receiving an electrolyte, characterized by a structure of the electrodes (10, 20) in thin-film planar technology the substrate (1), wherein an interdigital array of anode (20) and cathode (10) with individual electrode fingers (11, 11 ', ...; 21, 21 ', ...) is formed.

Description

The The invention relates to a reserve battery of anode and cathode as electrodes and a space for receiving an electrolyte according to the preamble of claim 1. In addition, the invention relates to a Method for producing such a reserve battery.

A Backup battery is a battery that is typically only once is useable and that itself by wetting with an electrolyte activated. For an application in the medical field, for example, the electrolyte Be body fluid.

extra batteries are already known. They are analogous to known primary batteries composed of anode, electrolyte space and cathode. Unlike such primary batteries However, with reserve batteries the space between the electrodes is not filled with electrolyte. Only when activated is the gap with ionically conductive electrolyte filled.

reserve batteries find application in signal lamps, such as lifejackets or the like, or for example as a torpedo drive. In both cases they are activated by penetrating seawater. Special advantage of backup batteries is the almost unlimited shelf life, because by the missing electrolyte a self-discharge in the usual Senses not possible is.

The Previously known systems of backup batteries are made of solid Electrodes assembled. As a result, they are not suitable for one flat design and such applications, for which a miniaturized Construction is necessary.

Although it is already known from the prior art to form arrangements in thin-film technology. This applies, for example, for a pyroelectric thin-film sensor element according to the DE 195 13 499 A1 or for an electronic card with IC chip and battery according to the DE 689 14 526 T2 , In addition, from WO 01/18830 A1 a thin-film capacitor is previously known, in which an oxide-ceramic layer is present on an electrically insulating substrate and a plurality of function-graded individual layers are present therebetween. The electrodes located thereon may be formed, for example meander-shaped in the manner of interdigital electrodes.

outgoing From the above prior art, it is an object of the invention, a Reserve battery to create, which is compact and, in particular, also is inexpensive.

The Task is inventively by the characterizing features of claim 1 solved. production method for one Such reserve battery are in the independent claims 9 to 11, 13 and 14 indicated. Further developments of the reserve battery according to the invention and the associated Manufacturing process are the subject of the dependent claims.

The Inventive backup battery is in thin-film planar technology realized with interdigital structure and individual electrode fingers. When used as intended shut down the electrode fingers enter the electrolyte. The thus formed backup battery can also be very simple due to its very simple structure getting produced. As a result, the structure is so cheap that he in particular also for so-called disposable applications, e.g. in medical diagnostics, in question comes.

Further Details and advantages of the invention will become apparent from the following Description of the figures of exemplary embodiments with reference to the drawing in conjunction with the claims. It each show in a schematic sectional view

1 the principle of a thin-film backup battery,

2 a backup battery in interdigital structure,

3 a backup battery according to 2 in sectional view and

4 the procedure for activating a backup battery.

Equivalent Units have the same reference numerals in the figures. The figures are described below partially together.

In 1 a structure is shown, which is a substrate layer 1 with a cathode thereon 10 and an anode 20 contains. cathode 10 and anode 20 each form a plurality of electrode fingers 11 . 11 ' , ... and 21 . 21 ' , ..., which are arranged parallel to each other. The electrode fingers 11 . 11 ' , ... and 21 . 21 ' , ... are part of interdigital electrodes. This means that the cathode 10 on the one hand and the on ode 20 on the other hand in each case a total comb-like design, wherein the individual cathode fingers 11 . 11 ' , ... and the individual anode fingers 21 . 21 ' , ... in pairs.

In 2 is a structure like in 1 present at the from the cathode 10 on the one hand and the anode 20 on the other hand, the interdigital electrode is formed with only a single electrode finger. The electrode finger 11 respectively. 21 each forms the complete electrode 10 respectively. 20 ,

In a modification to 1 and or 2 For example, the two or more electrode fingers may be formed in a spiral, meandering or other spiral arrangement.

Overall, in 1 and or 2 from the structures of cathode 10 and anode 20 on the substrate 1 It is important to choose the distance between the adjacent electrodes or electrode fingers as small as possible, wherein width b, distance a and thickness of the electrode layer are in each case of the same order of magnitude Dimensioning and the appropriate manufacturing processes will be discussed below.

From the sectional view of 3 is the substrate 1 with the electrode fingers on it 11 . 11 ' , ... and 21 . 21 ' , ... visible. It is a cover, eg a foil 30 , which is located at a distance above the electrode fingers, so that an electrolyte space 40 is formed. The electrolyte space 40 may optionally have a porous body for receiving an electrolyte.

In 4 is an arrangement according to 1 shown at the substrate 1 with cathode 10 and anode 20 on a discrete element, eg a sensor strip is applied. The arrangement is in an electrolyte 51 submersible. For example, this is a container 50 for receiving the electrolyte present.

In the arrangements according to the 1 to 4 are the electrodes 10 and 20 or electrode fingers 11 . 11 ' , ... and 21 . 21 ' , ... as thin layers, for example, with a thickness of 50 microns, formed. In general, the thickness of the electrodes should be between 10 and 100 μm. As the widest possible range thicknesses of 5 to 500 microns in question. The width b and the distance a of the electrode fingers are each tuned in detail.

The Production of thin Electrode layers are advantageously carried out according to a known Screen printing process. Possible it is also, the electrodes with a spray on a substrate applied. Optionally, it can be applied to the intermediate layer of the collector, provided that the electrodes directly the power connections attached become.

so thin layers can also created for example with a customized ink-jet printer become. Another possibility for the Production of the electrodes are printing processes, in particular the so-called pad printing or the like, further dipping method or the so-called Schlickergießen.

According to the principle of 1 to 4 Reserve batteries can be constructed which satisfy the given conditions with regard to the voltage or the current to be supplied. In this case, the number n of cells can be predetermined, wherein in general: n ≥ 2. It is essential that the electrolyte space 4 can be designed so that it has a capillary action for sucking the electrolyte. This can be realized for example by the thickness of the electrolyte space per se or by a porous body in direct contact with the electrodes. Such a body with capillary action is for example a fleece.

at The described reserve batteries can be one of the two electrodes, the electrolyte space or the porous body contained therein, the represents the separator, a soluble Salt are added. This can either be a water-soluble, be electrically conductive salt for filling with water or aqueous solutions or also a conductive salt for organic liquids.

To activate using the 1 to 4 described reserve batteries, the arrangement is connected to an electrolyte reservoir. By mechanical pressure on the electrolyte reservoir of the electrolyte is pressed into the electrolyte space and thus made the battery ready for use.

When Electrolyte are all liquids suitable, the at least a slight ionic conductivity exhibit. In a medical application, this may be a body fluid, like blood, urine or saliva.

Of the Electrolyte can also directly the liquid to be analyzed be. This is beneficial for the use of so-called disposable applications in medical technology. For such Disposable applications is an ultra-thin design with low material usage and the ease of manufacture advantageous.

When in contact with a liquid, the battery and the electronic circuit connected to it activates automatically. Activation by the analysis fluid thus acts as a smart one Switch.

Claims (14)

Reserve battery having an anode and a cathode as electrodes of 5 to 500 μm thickness on a substrate and a free space for receiving an electrolyte, characterized by a structure of the electrodes ( 10 . 20 ) in thin-film planar technology on the substrate ( 1 ), wherein an interdigital array of anode ( 20 ) and cathode ( 10 ) with individual electrode fingers ( 11 . 11 ' , ...; 21 . 21 ' , ...) is formed. Reserve battery according to claim 1, characterized in that the anode ( 20 ) and cathode ( 30 ) by two adjacent electrode fingers ( 11 . 11 ' , ... 20 . 20 ' , ...) are formed. Reserve battery according to claim 2, characterized in that the distance between two adjacent electrode fingers ( 11 . 11 ' , ... 21 . 21 ' , ...) is selected according to the respective electrode thickness. Backup battery according to claim 1, characterized the thickness of the electrodes is between 10 and 100 μm. Reserve battery according to one of claims 1 to 4, characterized in that the electrode fingers ( 11 . 11 ' , ... 21 . 21 ' , ...) are formed in a spiral arrangement, for example spirally or meandering. Reserve battery according to one of the preceding claims, characterized in that a cover ( 30 ) for forming an electrolyte space ( 40 ) with capillary action for an electrolyte ( 51 ) is available. Reserve battery according to Claim 6, characterized in that, to form the capillary action, the electrolyte space ( 40 ) with cover ( 30 ) has a small thickness. Reserve battery according to one of claims 1 to 5, characterized in that the on the substrate ( 1 ) applied electrodes ( 10 . 20 ) have a free surface, wherein the substrate ( 1 ) with the electrodes ( 10 . 20 ) for wetting the electrode surfaces in the electrolyte ( 51 ) is submersible. Reserve battery according to claim 8, characterized in that the substrate ( 1 ) with the electrodes ( 10 . 20 ) forms a strip for wetting the electrode surfaces into a container ( 50 ) with electrolyte ( 51 ) is submersible. Method for producing a reserve battery according to the claims 1 to 9, characterized in that the electrodes by screen printing be applied to the substrate. Method for producing a reserve battery according to one of the claims 1 to 9, characterized in that the electrodes by spraying the substrate are applied. Method according to claim 11, characterized in that that for the spray process a so-called ink-jet printer is used. Method for producing a reserve battery according to one of the claims 1 to 9, characterized in that the electrodes by printing, preferably a pad printing, are applied to the substrate. Method for producing a reserve battery according to one of the claims 1 to 9, characterized in that the electrodes by dipping or slip be applied to the substrate.