DE2009063A1 - - Google Patents

Description

TO RUCH

PATENT ADVOCATE

MONKS 5

REICHENBACHSTR. 51

TEL 263251

PM-273 / W
. R / Sch
6th

Leesona Corporation, Warwick, Rhode Island, USA

Metal / oxygen element with consuming anode

The invention relates to a metal / oxygen element with a consuming anode and a cathode consisting of a hydrophobic membrane whose side facing the electrolyte of the element is covered with an electrochemically active catalyst. The cathode such an element may * when it is sealed against the ingress of liquid, under water, for example, in oceanography or in electrical or electronic navigation aids verwandet _a on the one hand prevents the entry of water into the element, but on the other hand, the aqueous in the Medium dissolved oxygen can pass through ..

In many areas of technology, portable sources are required -for electrical energy that also works under water. Metal / air or metal / oxygen elements and batteries have many properties * the prerequisites for such

009838/1515

Uses are, such as robustness, simplicity of construction, Portability, and the ability to deliver low currents over long periods of time, however, it was believed that such Elements for the current-supplying conversion at the cathode require atmospheric oxygen or when using them underwater with a portable source of oxygen must be provided, which is complex and expensive and all the advantages of such an element listed above would weigh out »The charging of such an element or such a battery causes difficulties, because either a suitable direct current source must be available, which is problematic at sea under! The anode must be replaced and made accessible for this purpose, i.e. the element which is watertight during operation must be disconnected.

The object of the invention is therefore a metal / air element that for the stream-supplying conversion in an aqueous medium able to use dissolved oxygen and can therefore be used underwater without its own air or oxygen source and can be easily charged, for example by mechanically replace the anode.

The subject of the invention is a metal / oxygen element with a consuming metallic anode, a cathode on an oxygen-permeable liquid-impermeable hydrophobic membrane, the side of which facing the electrolyte has a layer of an electrochemically active catalystί an electrolyte between anode and cathode and a " .node, cathode and electrolyte enclosing housing, which is characterized in that the housing means »around

BATH ORIGINAL 009838/1515

Anode, catalytic surface of the cathode and electrolyte complete liquid-tight against the environment, as well Means for an oxygen-containing aqueous medium surrounding the element in contact with the hydrophobic surface of the To let the cathode occur, has.

Surprisingly, it was found that the in which the element surrounding aqueous medium, i.e. the water of seas, lakes | and rivers «and through the hydrophobic membrane of the Cathode at the catalytic layer.gelangende amount of oxygen is generally sufficient to supply the energy Implementation at the cathode so that the element is entertained a small current can be drawn over a long period of time.

The oxygen-permeable, water-impermeable membrane of the Cathode is made of a hydrophobic fluorocarbon polymer, such as polytetrafluoroethylene, polyhexafluoropropylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride and copolymers thereof. The electrochemically active catalyst consists of one of the metals known for this purpose and preferably of a metal from group VIII or IB of the period ' systems. The catalytic metal can be polymerized with a hydrophobic fluorocarbon such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polytrifluorochloroethylene Copolymers thereof may be mixed.

The consuming anode can be any metal that is more electropositive than oxygen, such as zinc, magnesium, aluminum, iron, cadmium, lead, or the like. Cadmium and iron work well, and the preferred metal is zinc. The anode may be in the form of a solid plate or a porous microstructure _r * have for example, a. Nejfcjz or ,, sieve covered with spongy metal.

009838/1515 _eAD ORIGINAL

The electrolyte used in the element according to the invention may be an acid, a base or a salt, for example in the form of an aqueous solution or paste, or an ion exchange medium, or it may be contained in a porous structure. Since the element according to the invention is intended to deliver only a small current, practically any ion-conducting medium can be used. Examples of suitable salts are fk ammonium chloride and potassium carbonate. Examples of suitable Acids are phosphoric acid and sulfuric acid »Preferably a basic electrolyte, for example an alkali hydroxide, such as potassium hydroxide used. The use of an electrolyte paste or a porous structure soaked with the electrolyte is known to have advantages over the use of free-flowing liquids, especially if the anode is yours Should keep shape. In order to maintain the shape of the consumable metallic anode, any of the usual Separators are used.

The manufacture of the cathode used in the element according to the invention can be carried out as in the US patent application P Serial Number 533 516 dated March 11, 1966 by Harry G. Oswin described. Preferably, the catalyst, which instead of an element of group VIII or IB also an element of Group IIB, IV, V, VI, VII or an alloy or an oxide such an element or carbon, preferably in finely divided form, for example as metal black, like platinum black, with a finely dispersed hydrophobic polymer mixed, and the mixture is rolled onto the membrane made of the hydrophobic polymer and under slight pressure with or without applying heat attached to it, above the catalytic A hydrophilic membrane, for example a separator, can also be arranged on the layer of the cathode.

009838/1515

2Q09Q63

Of the invention be formed so mu3 ■ The housing of the element or of the battery according that it prevents the ingress of water into the interior of the element or of the battery. It can consist of a hydrophobic polymer or be coated with a layer or a film of such a polymer, and it can be formed in one piece with the hydrophobic membrane of the cathode. For example, the housing can consist of a rigid or deformable watertight frame made of a _{: Ä}

hydrophobic polymer or the like. exist, and in this context can the cathode membrane must be clamped and bound to it in such a way that it is not covered by the catalytic layer Side facing the environment of the element 1st, while the Anode, the electrolyte and the one with the catalytic layer covered side of the cathode are located within "the frame. After the anode is inserted and the electrolyte is filled 1st, the frame can be permanently sealed so that the whole element is enclosed in a waterproof housing is. Such a permanently sealed housing can of course only be used for primary elements while for elements with exchangeable anode housings that have means for opening and resealing are used (

have to. ----

In each pail, however, the housing must be designed in such a way that Water can get to the hydrophobic side of the cathode.

Water can dissolve most gases, and rivers, lakes and Oceans always contain oxygen »The oxygen concentration of sea water is about l4 ~ g / m ^. The air at sea level would contain about 250 g / nP oxygen »It is therefore surprising that the relatively small amount of oxygen dissolved in water has an electrochemical reaction, see below able. The present invention is based on the discovery

00 98 38/1515 -

that the oxygen dissolved in water is able to pass through the hydrophobic side of the cathode used in the elements according to the invention unexpectedly quickly and in unexpectedly large quantities , so that sufficient current densities can be taken from such an element for many technical purposes.

φ If zinc / air batteries according to the invention are under water

Temperatures of 15 ⁵ C to 90 ⁰ C are used, a current density of 1 to 5 mA / cm at a voltage of 1.0 to 1.4 V can be taken from them over a long period of time, which is useful for the operation of various electrical and electronic devices Underwater equipment is sufficient. Good current densities can also be achieved with anodes made of metals other than zinc; However, zinc is the preferred Anodentnetall, in the temperature range of 0 "C to 15 ⁰ C, the achievable current densities are of course less. However, also in the vicinity of ⁰ ° C or current density"! be obtained "the _s particularly when bonded with polytetrafluoroethylene platinum used as a catalyst in the cathode is still sufficient for many purposes

W are.

The effect of the method can be further improved if a current collector, preferably a porous metallic element, for example a metal gas, a metal rod or the like, made for example of nickel, is in contact with the catalytic layer. Tantalum ^ tungsten, fiatin, gold, silver or the like, used,

The elements according to the invention are preferably designed in such a way that that the anode can be replaced. Metal / air EXeTiente Replaceable batteries and batteries are in the "a enth ame Idling P 15 96 J 69 · C irr ^ lsf.ei en applicant dated

009S3 9/1515

Described December 28, 1966. The element described in this earlier application has a seheldenfuxmIge cathode and a replaceable anode inserted and held therein. The element according to the present invention Of course, it must have a housing that prevents entry is sealed from water »for example one with clamps, Has bolts or screws sealed cover. Of the. The frame of the case can be made of rubber, a synthetic resin or another suitable material and formed cylindrical or with a rectangular cross-section be.

In the drawings shows

Figure 1 shows the disassembled parts of an individual element according to the invention with a replaceable anode,

Figure 2 is a cross-section through the assembled element of Figure 1 along line 2-2 of Figure 1 and

Figure 3 shows the partially disassembled parts of a multi-element battery according to the invention.

The preferred embodiment of an element according to the invention shown in FIGS. 1 and 2 has an exchangeable anode to, a cathode 20 and a porous covering 13 comprising the active material 1 * of the anode 10. The enclosure 1> contains the electrolyte of the element that is filled or refilled through the opening 10E. That Anode material 1Λ is porous and can solidify it contain a metal gauze or a metal net embedded.

009838/1515

The upper part 11 of the anode 10 consists of an electrically insulating material and has a handle 15 which makes it easier to remove the anode from the element. The anode connection 12 is formed in one piece with the upper part 11 of the anode and is in electrical contact with the active one Material 14. A conduit 16 is attached to connector 12. The porous envelope 13 consists of glassine, but can also P consist of some other hydrophilic membrane or ion transfer medium.

The anode 10 is the shield-shaped cathode 20 precisely adapted. The structure of the sheath-shaped cathode is shown more clearly in FIG. This cathode consists of two hydrophobic membranes 23 * whose inner surfaces are covered with a catalytic layer 21. A power collector network 24 is in contact with the catalyst 21. The two sides of the sheath-shaped cathode can be electrically insulated from one another or connected to one another by wires. In the embodiment shown in Figures 1 and 2, a wire, not shown, connects the two current collectors "24, so that the cathode connection 26 is electrically connected to both current collectors 24. A line 27 is connected to the connection 26 attached.

The sheath-shaped cathode, which comprises the replaceable anode, is in turn surrounded by a housing 30. The housing 30 is provided with a mesh 31 * which prevents damage to the hydrophobic membrane 23 prevented by objects floating in the water, formed. In Figure 1 is a part of this Mesh 31 is omitted so that the arrangement of the hydrophobic membrane 23 can be seen. The current collector 24 is indeed at the Inside the cathode 20 arranged, but is through the

009838/1515

-Q-

hydrophobic membrane 23 visible through »The one shown in FIG Catalyst 21 cannot be seen in FIG. 3.

The housing 30 has a bottom part 35 on which the protective net 31 and the outer surface of the cathode 20, ä, h. the hydrophobic membrane 23 is attached. The bottom part 35 has means for attaching the battery to an underwater device or the like. The bottom part 35 consists of Polytefcrafluorathylen, {but can also consist of any other electrically insulating and water-impermeable material. It Jsami by any known method, "etching method, for example, a sodium, by Polytetrafluoräthylencopolymerverklebung, metallization, metal bond or Sinterungj_ the cathode _v be bonded 20 to the outer surface. E & need not be gas permeable, such as the hydrophobic membrane. On the upper part 32 of the housing 30 is a flange 33 is provided. This upper part and the side part 37 (Figure i) are connected to the sheath-shaped cathode 20 in the same way as the bottom part 35 Easiest to manufacture as a one-piece unit into which the cathode 20 is inserted and to which it is bound, after which the protective net 3 & is attached.

The flange 33 has holes 34 for receiving bolts. A lid 40 and a seal 41, both also made up are made of an electrically insulating material, also have holes 44 for receiving bolts. Cover 40 and flange 33 with the seal 41 in between are secured by bolts or screws and nuts (not shown) kept together watertight. Before screwing together the lines 16 and 27 are introduced through watertight guides 42 baw «43.

009838/1515

- ίο -

The element assembled in this way is completely watertight. Only oxygen can pass through the hydrophobic membrane 23 get into the interior of the element. However, if the den Lid 40 clamping screws can be loosened, the Anode 10 can easily be removed by means of the handle 15 and a new anode can be inserted.

Figure 3 shows a battery composed of a number of elements. Part of the housing 130 is omitted to show the arrangement of the sheath-shaped cathodes 120. The battery contains six sheath-shaped cathodes i20 and six anodes 100. The six elements are connected to one another by conductors 1.50. Sis are connected in series, but can of course also be connected in parallel. When the conductors 1 '} 0 are removed, the anodes 100 can be pulled out of the cathodes by means of the handles 15. Since the elements are connected in series, the anode terminals 112 are connected to the plastic terminals 126. One of the kafchode connections 126 has a line 127 * and one of the anode connections 112 has a line 116. These lines

™ 127 and % l6 are guided by watertight guides 142 and 143 in the cover l * '* 0. As in the embodiment of an element according to the invention shown in FIGS. 1 and 2, the cover 140 is connected to the flange 133 of the housing 130. The upper part 132 and the lower part 135 of the housing 130 are bonded to the outer surfaces of the cathodes 120. The connection is made as in the embodiment shown in FIGS. When the parts shown in Figure 3 are combined to form a battery, sealed and kept under water, so has the WASR · r- through the network 13 * pass pass the hydrophobic membrane au 123- That is, the water can flow freely through the battery soue &'y constantly fresh oxygen to the Kai-testoden i20-ge TU \ ■■■>;' will.

001838/1515 "

- Ii -

The main features of the battery shown in FIG are of course the same as those of the embodiment of an element or an element shown in FIGS single cell battery according to the invention. Lower housing part 135 »upper housing part 132 and side parts 137 can be combined

be formed in one piece and bound to the sheath-shaped cathodes. The electrolyte can be filled through filling openings LOOE or supplemented, and the upper housing part 32 or 132 and cover ¹ K) or 140 form if they are comparable to each other "screwed" flUsslgkeitsdicht a small sealed space above the cell or row / as 2 and 3. In this space are housed the electrical connections etc. If the element or the battery is "used which is conductive" in salt water, it is of course of particular importance that these connections are not connected to water come into contact or are completely isolated. This space can be filled with a removable polymer or the like. However, it is preferably kept empty so that gases rising from the anode 10 or the anodes 100 can collect therein.

In the embodiments shown in the drawings, the Cathodes 20 or 120 are shielded by nets 31 or 131. Alternatively, oxygen-permeable hydrophilic films can be used instead of such nets. When using such films the amount of water * that reaches the cathodes 20 or 120 can be measured.

The following examples illustrate the invention. example 1

Xn the housing 30 shown in Figures 1 and 2 were as Cathodes two 0.18 mm thick Polycetrafluoräthyleitfolien, the 3on one side with a layer of a mixture of platinum.

009838/1515

black and polytetrafluoroethylene particles, into which a nickel mesh was pressed as a current collector, were "coated," so arranged that the side covered with the catalyst faced the inside of the element. In this way, a sheath-shaped cathode unit was obtained. The amount of platinum

carried 10 mg / cm cathode area. The anode *, a porous zinc foil encased in glassine, was inserted between the two catalytic surfaces of the cathode unit. The glassine was impregnated with a 30% aqueous potassium hydroxide solution as an electrolyte. The anode and cathode connections were passed through the watertight guides in the cover 40, and the cover 40 and seal 41 were screwed to the flange 33 of the housing 30. After sealing, the element was completely immersed in water in a container and put into operation ^{at 25 ° C.} The voltage with an open circuit was 1.44 V. The element had to deliver 0.7 A, corresponding to 3 * 5 mA / cm, over 10 hours. The initial voltage at this load was less than 1.17 V, but rose to 1.23 V within an hour. About two and a half hours later the voltage reached a maximum value of 1.26 V and then slowly began to decrease, but increased at no point in time significantly less than 1.15 V.

Example 2 An element essentially similar to that of Example 1 was used

operated under water at 25Έ at a current density of 0.5 mA / cm. The open circuit voltage was 1.43 V. The initial voltage when current was drawn decreased to 1.21 V and rose rapidly to 1.25 V. Less than two hours later, the voltage peaked at 1.29 V. Neither At this point within ten hours of current consumption, the voltage fell significantly below 1.2 V. After that, the element was at same current consumption in a container with V / water of

009838/1515

held. Under these conditions the tension remained greater than 1.05 V.

0018 387 1515

Claims (11)

Patent to s ρ r Ü c h e (O metal / oxygen element with consuming anode, 'a cathode made of an oxygen-permeable, liquid-impermeable hydrophobic membrane' whose side facing the electrolyte has a layer of an electrochemically active catalyst, an electrolyte between anode and cathode and an anode enclosing the cathode and electrolyte housing, characterized in that the housing means "to anode catalytic surface of the cathode and electrolyte flüssigkeitßdicht complete against the environment, as well as to make contact with the hydrophobic surface of the cathode means van an element surrounding oxygen-containing" äseriges medium comprising . 2. Element according to claim 1, characterized in that the catalyst consists of a metal from group VIII or IB of the periodic table and the oxygen-permeable, liquid-impermeable hydrophobic membrane consists of polytetrafluoroethylene. 2. Element naoh claim 2, characterized in that <sa3 the catalyst is a metal black one Metal of group VIZI of the periodic table and is in intimate combination with foiKÜspersem polytetrafluoroethylene. 4. Element i? Ach one of the preceding claims, that - ά u ν Q h characterized that the see consumable anode is made of zinc. 3 3/1515 20Q9063 5. Element according to any one of the preceding claims, characterized ge k en η ze rejects that the electrolyte is contained in a hydrophilic film. 6. Element according to claim 5, characterized / that the hydrophilic film (10) which is consuming metallic anode (1 * 0 envelops. 7. Element according to claim 1, characterized in that g e fc e η η - | draw t that consumable metallic Anode (14 * 10) within the sheath-shaped and is arranged integrally with the housing coherent cathode (20, 120). 8. Element according to claim 7 «characterized * that the housing is sealed watertight by a removable cover OK), 140) and sealing means (11,41; 133,1 ^{1 H).} 9. Element according to claim 8, characterized in that the anode (10, 14; 100) is exchangeable is. ■ - ■ .- ■ .. ■ "■ .- .; I 10. Process for generating electrical energy, d a -d u r c h g © indicates that a metal / Oxygen element according to one of the preceding claims operates underwater with the oxygen dissolved in the water. 11. The method according to claim 10, characterized g e k e η η -ζ el c h η e t that the element or one of such The existing battery in natural fresh or salt water. 0B9838 / 1515