Dry cell whose separator includes/understands a composition of paste.

The present invention relates to enhancing register? the dry-type.^H to paste " in order to address the shortcomings: severe discharges. and long-lasting, generally involuntary, excludes prejudice major hardware containing batteries,

It is known that a dry cell, subjected to a short circuit, or strong discharge until the voltage reaches zero, "cast". According to a type connu.de dry cell, it comprises in its general structure; a cylindrical cup made of zinc, constituting, the anode, a cathode formed by a depolarizing mixture base.de manganese dioxide, a collector and a separator paper impregnated or-IRA àtoase paste of flour and d!. starch. An electrolyte is: immobilized in the separator and in the depolarizing mixture.

During a normal discharge, - the products of chemical reactions diffuse towards the anode. the cathode (Zn-c12 in solution). Under discharge fortemepî. compelling, the. forming desired d'électrodes,-is faster than diffusion thereof, and. this, the more

It is•. shape, sputtering the interface, insoluble products cqlnpajants who interfere with this diffusion. Therefore, the concentration: in zn, c12 increases in-such, amount S than the pH decreases worm? very low values (g 2.5).. the components constituting 4a " grams $tee (freeze) are hydrolyzed. They become viscous liquids, entrapping the offgases 1 1 ℮ΐ Εηο ε, (2 Η). Furthermore, the electrolyte increasingly acid, zinc and gives off more and more. pjus hydrogen. Under the effect of gas, pressure, the electrolyte and the paste (as applicable) are expelled.

-, Expulsion results in an upward, toward the free space above the

the cathode -, j is optional. beyond the plug closing the cylindrical cup of the stack. It is also the. along the vertical wall, zinc has completely disappeared by location. The member surrounding the cup D. © Zn. (pipe cardboard, foil) does absorbeuen general that low. quantities, otherwise nothing. The surplus ^'d ' 4th or electrolyte paste and Nutrition to flow, and to. atteiridi ' is greatly accelerated, and in partieliaute. low, the, cups covering the cup of the stack which do, not protected, these are then badly damaged. When these various phenomena occur, referred that the stack "cast" -.

. Also many searches was to remedy this defect " numerous patents have been granted, whose purpose, either collected - absprber or the electrolyte which is expelled ., of preventing it from passing through the plug, soitsoit.d ' provide, an improved ventilation could both. Various techniques for safeguarding the coupcllefimetaliic background or higher, particularly by means of plastic rings crimped. Finally, it is possible to improve Ijemballage by providing cpuches of intercalation of waterproof, the electrolyte or the dough, e.g. simple or heat shrinkable films combined absorbent diapers generally multi-layer paper or board.

In the case of dry cells to "paste", gel blocking which becomes viscous can be caused, according to a first method, by additions of products. The latter react with zinc chloride to form insoluble compounds that promote retention of the paste. One another. method, it is proposed. selecting starches or. flours. - pretreated (to the épichiorohydrine) for which there is blocking after making; the stack, with certain precautions to be taken at the time of preparation of the paste before introduction into the bucket zinc.

It is noted, ; currently still, a variety of yields ranged from the cell. the dough godgod.et zinc serves as container, up to stacks "motorcars, pentaligne" aigodet. protected by a shell therrnorétraçtable under metal jacket. All these varieties, does. not have the best efficiency with respect to the tightness. The improvements, from: these various stages, will support on the protective layers, the rings, the sealing plugs, . like ;. It is found on the one hand, that these, using assemblies by crimping and contact, by pressure. of two materials, cannot give full enjoyment.., sealed arrangement of against liquids, on the other hand, they pose of changes - -

- important installations and multiplying peers in manufacture. In the_; case of

previously evoked paste - cell, the method comprising first - add^- reaction products with le zinc chloride, is not sure; as to the second method ' using starches or flours preprocessed, it is implementing delicate. -••. :?

. The present invention provides the locking of the dough, after gelling.. in-the usual conditions. For celadon incorporates, in the composition. the paste, an insolubilizing flour and starch. The insolubilizing is preferably a derivative of methylol melamines éthérifiê: a methyl ether of methylol melamine. This product has the advantage of condense rapidly and completely;, even at low condensing temperatures. In addition to these there the good stability at bay warehouse and its compatibility avecavec.d'other components, appearing above all in the viscosity. The rheological babies■properties. are not compromised. The groups métmét.hylol allow reaction. with the amino groups and with the groups hÿdroxyles starch and the ' to-flour, as well as with other elements, melamine. As a result of insoluble three-dimensional large molecules and a canting founded sensitive.' the the presence of zinc chloride and ammonium chloride is not a disadvantage, they play a role of the contrary - catalyst. The cross-linking is relatively fast the first two days, then slower, obtained therefrom the full efficiency after two weeks of storage.

: - A, composition for paste serving as separator. in the dry cells, as rinyerition, can respond th la - following general formula, wherein the percentages are based on the weight of the PGCs coropositioji wet..

C/o Emdults

Flour 10 - 15

Starch - 1 ., .... 3 - 6

Ammonium chloride........ 15 - 25

Zinc chloride 10 - 20

Water.... 42 - 48

Inhibitor, insolubilizing...........

The composition decomposes, typically in two mixtures prior to introduction

•covering. A first mixture includes flour - especially - panel-wheat flour, starch, amrnonium chloride and water, and a second-mixture comprises ammonium chloride, zinc chloride, water and an inhibitor. These two mixtures are injected

- " simultaneously in the ' stack two pumps on the assembly line. The conjunction of the two mixtures results the gelling conditions depending on conditions.. outer.

. In this scheme, it is advantageous to incorporate the L.' ether methyl. méîbylolméiamine in the mixture lacking the flour and t'amidon,-to-.c'est e. in. the second, to pull the. best advantage of the insolubilisarit, the content of [' is 5 to 12% insolubilizing relative solid content weight of flour and starch, either. 0.5 to 2.5% in the formula described above.

The preparation of these mixtures does not have a particular modifications with respect to what is normally formed in the battery industry. Examples SUI provides follow illustrate a number, non-limiting, dough compositions for dry cells according to the invention, it will be possible to adapt as circumstances dictate.

Products: * the composition in %

Example 1 example 2 example 3

Methyl méthylomélamine ether compounds, such as: - Liofix CHNs Pergaprint has or

CIBA-GEIGY (HM)