DE1008798B - Active mass for lead accumulators produced with the addition of hydrophilic substances and process for their production - Google Patents

Description

GERMAN

The invention relates to the active mass for the plates of lead batteries and to a method for their manufacture.

The known methods for the production of lead batteries are that the grid with a Mixture of lead oxide, for example black lead, containing metallic lead, red lead and other additives can be pasted from sulfuric acid. The mixture of black lead and acid forms a plastic one Mass that can be pressed into the gaps in the grid and that forms a hard, cohesive one when it dries Forms material that easily adheres to the grids of the plate.

This plastic mass is created by the chemical reaction between black lead and sulfuric acid, whereby a considerable proportion of lead sulphate is formed. Such a paste has desirable properties in terms of density, consistency and adhesiveness, all of which are required for successful pasting of the plate are. In general, the use of sulfuric acid in making the paste is one of them common practice used in engineering.

The effects of the sulfuric acid and lead sulphate in the paste mixture seem to lead to an increase in the volume of the paste, whereby the density is significantly reduced, the mixture is thickened so that its consistency ensures the desired plasticity, and the adhesiveness of the paste is increased. Such a paste has a density of about 4.27 g / cm ³ .

Efforts have long been made to use sulfuric acid and lead sulfate in the manufacture of the Avoid pastes. To date, such attempts have generally been, and are not, unsuccessful Known attempts which have led to an application on an industrial basis to a significant extent to have. In addition to the fundamental objection based on the corrosive effect of sulfuric acid, speak further essential reasons against the use of sulfuric acid in the manufacture of the paste. The sulfuric acid generates considerable heat in the paste mixture, which is often detrimental to the properties of the paste influenced. In addition, it hardens and sets in a short time without restoring its original properties can be. Furthermore, there has always been a need for simpler, faster and more economical Process in paste production.

Lead sulphate has been added to the active mass in a limited amount, but this is to be rejected, because it gives the paste properties that are inferior to those produced by the use of sulfuric acid are conditional. The use of lead sulfate is of no economic interest; she leads rather, it leads to new problems with regard to admixing and homogeneous distribution.

With the addition of hydrophilic substances

manufactured active mass

for lead batteries

and methods of making them

Applicant:

National Lead Company Inc.,
New York, NY (V. St. A.)

Representative: Dipl.-Ing. J. Pfenning, patent attorney,
Berlin-Charlottenburg 9, Bayernallee 15

Claimed priority:
V. St. v. America December 13, 1952

Bernard Agruss, (East Orange, NJ,
and Frank Bernard Finan, Hicksville, Long Island,

NY (V. St. A.),
have been named as inventors

Using the invention results in a new active mass for the plates of lead batteries, the allows easier control of the physical properties than with the previously known active compositions. The invention ensures an improved production of lead batteries and leads to an active mass of relatively low density, which is characterized by good adhesion and one that is within wide limits controllable consistency of the paste. The invention also results in an active mass that can be used for single-stage Formation of lead batteries is suitable.

The present invention relates to the manufacture of an active composition and is characterized by a lead oxide, which in intimate mixing has a small proportion, in particular 0.1 to 2 percent by weight, of a

709 510/168

contains hydrophilic substance, which has a very high absorbency compared to water. The term absorbency includes all of these Substances have inherent water-absorbing powers, regardless of whether they are of a physical or chemical nature are. This water-absorbing property can be expressed by that of a unit weight the weight of the water taken up or absorbed by the hydrophilic substance.

Oxydmaterials to ensure. The amount of this remedy in the active mass should generally not exceed 2%, as the use of larger amounts - Desired dilution of the active lead oxide mass occurs and the correct capacity and the others for one Accumulator properties are difficult to achieve.

The use of less than 0.1 ° / ₀ hydrophilic

The hydrophilic substances have the ability in io substance satisfactory effect when added relative to their own weight or mass will have large ^v0 "water and do not lead to a paste to include the amounts of water. They soak up the water in ^{the grids of the plates with} satisfactory success that it loses its nature as a liquid and becomes
Part of a plastic or semi-rigid material

can be pasted.

Among the hydrophilic substances that are responsible for active ma-

JLSlO IC3.1J.IX LIsJLJ. V ^ JJJL \ _O LSXOiJ IJL3 ^ i-IV- A JL W1A_> JL AiU.JUI- '^ JL.CiJl i .- \ s ± i J.IJLU, LV ^ J. 4.CViO · ■! Alt 1 TI ·. 1 · TT ill ·

will. Under these conditions, the water is addressed as a tenal of accumulators and for the production of structural water and is used in the present f **? g ^eei f ^{et S1} * ^d> ^ ^hore _r ^n? * f ^{r What} gent CeUudenErnndungimwesentlichenalsein volumenvergrößern- l fdenvate °, in particular Celluloseather as lower dm of the middle. This is expediently imagined as alkyl, oxyalkyl and carboxyalkyl ethers, for example a plastic material made from a hydrophilic substance sodium carboxymethylceous, carboxymethyloxy and water with lead oxide dispersed in it. This ao athylceUulose, methylceUulose and oxycellulose material contains the necessary lead oxide in a cohesive ^. ^{or specific} pf ₊ compounds such as Natrmmbentonit and ground, but at the same time keeps the oxide particles separated starch derivatives such as low substituted em enough to have a relatively low density of strong derivative to ensure the Carbonsaure- and sulfuric acid active composition. So far, the necessary groups have been included. ^ _{1111 r} 1, volume increase achieved by sulfuric acid or 25 *%. F ^he ^ ⁿⁿ ^ carboxymethyl cellulose in a mixture of lead sulfate. According to the present invention, these zinc oxide in pastes made of an active material for electrodes exert hydrophilic substances which contain more than 20 g of water. to use alkaline accumulators ^ can absorb per g of hydrophilic substance, and that. ^B f the water absorption capacity of the water practically the same function for the application. The lead sulfate ^{at r} .J invention advantageous hydrophilic substances in the paste by the economic, volumenver- 30 ^he ^ ^{bt SLCH from the fol} g ^{ends table:} replaced größernde material to 97 or more percent
consists of water and has a density of approximately 1 g / cm ³
owns. Further advantages of the invention emerge from
the following description and examples.

A relatively large number of hydrophilic substances are known per se. It is also already known add gelatine, glutin allergen and gelatinous silicas to the active mass. It is also known Cellulose and cellulose derivatives as hydrophilic

Table I.

Sodium carboxymethyl cellulose
Carboxymethyloxyethyl cellulose

Substance to use. However, these substances have 40 methylcellulose

core satisfactory suitability as hydrophilic substances oxyethyl cellulose

for active masses.

It is also known to add cellulose or cellulose compounds to the active composition. These well-known Cellulose compounds, however, do not have the required Water absorption capacity in order to influence the paste consistency in a favorable manner; they are so far exclusively used to give the paste a porosity to the surface of the using the Paste made to enlarge plate.

According to the invention, only those substances are for the active mass usable, which have a high degree of absorbency or have the ability to very absorb large amounts of water. The for the her-

Sodium bentonite
Starch derivatives

Water absorption capacity (g water / g substance)

45 40 35 30 20 20

Preferably, an intimate dry mixture of the hydrophilic substance with the lead oxide is made; the usual mixing apparatus suitable for such purposes can be used here, but it is not required to work by this preferred method. The hydrophilic substance can also be in a appropriate amount of water incorporated and the lead oxide added; it can also lead oxide and absr

position of lead batteries suitable hydrophilic 55 water mixed into a paste and the hydrophilic Substances are therefore characterized by a water substance to be entered into this paste, capacity of at least 20 g of water per g of the lead oxide used mentioned in the description

hydrophilic substance. This water absorption capacity is generally black lead in large quantities, often up to is defined by the maximum amount of water that can contain 30 or 50% of the finely divided metallic lead. That Hydrophilic material can be added and lead oxide can be made entirely from black lead or from black lead is absorbed by the material, with a half with red lead, spreading agents and other lead oxides,

as they are commonly used in practice.

Before detailed information about the invention is given, it should be pointed out that the paste in general can be characterized by the volume weight or the density and by the paste consistency. The active material commonly used generally has a volume weight or density of

rigid body with properties of a gel is formed. These hydrophilic substances are used in amounts of 0.1 to 2 percent by weight, based on dry lead oxide, applied.

Substances that have a water absorption capacity of less than 20 g per g of substance are suitable for those according to the invention Unsuitable purposes because they cannot absorb enough water to be used when used

the correct plasticity of the lead 70 3.95 to 4.40 g / cm ³ . The consistency is expressed as a penetration

5 6

depth of penetration measured in a penetrometer, the general results for achieving optimal performance and nits are empirical. The penetrometer used is preferable to a lead accumulator,
has sinker (needle), axis and weights in this accumulator was reassembled

a total weight of 240 g. The sinker is and in terms of its performance and its service life 51 mm long and 12.7 mm in diameter; S checked. Its initial capacity was equivalent to that lower end of the sinker in a length of those of the commercially available accumulators with 100 19 mm is tapered and runs in one ampere-hour; its lifespan amounted to blunt tip from which a diameter of 2.38 mm 447 discharges.

owns. The lower end of the sinker is 3.1 mm. For comparison purposes, a 6-volt accumulator was used

suspended above the paste sample. If the sink- io using one made from black lead and sulfuric acid body is released, it penetrates the paste; the existing paste without carboxymethyl cellulose - penetration depth is measured in millimeters. represents. The positive paste material had a density of

A consistency of 8 (8 mm penetration depth) indicates 3.87 g / cm ³ , the negative paste such a density of indicates a paste consistency that is approximately 4.21 g / cm ³ . The assembled accumulator would correspond to a stiff paste consistency, as it is generally intended to be filled with a sulfuric acid of a specific gravity in the pasting machines in the art of 1.324 and used for 40 hours at IS Amp. The number 12 loads a paste. The investigation showed that the surface consistency was marked, which corresponds to that of a paste of the positive plates covered to 40% with lead sulphate, which were used in machines for softer pastes, that is, the plates are not turned over completely formed. The number 20 denotes a paste box of 20 goods. The greater amperage and the longer charging time, which corresponds to that of a paste, as it would have to be used in pasting by hand for a faster and more complete one. Need to lead formation. This comparison represents the

The following examples serve to explain the remarkable ease of shaping the active tion of the invention. Materials according to the invention to prove.

In these examples, the visible area of the white lead sulfate formed on the active material was used as mulators using the usual lead designation for the degree of formation. smooth acid pastes with a density of 3.90 g / cm ³ for a fully formed positive plate has a surface of the positive and a density of 4.39 g / cm ³ for the surface that no longer shows any lead sulfate. The largest proportion of negative plates and the use of two hydrophilic substances is destroyed during the formation of a 30-stage charge, ie a first charge at 13 amps, of the plates, but a small portion remains in the plate for 24 hours with an acid of specific gravity . of 1.080 and a subsequent second charge

5 to 6 amps and 16 hours with an electrolyte of

Example 1 a specific gravity of 1.380. These accumulative

35 gates were made with an acid with a specific

For positive plates, 2722 g of black lead were filled with a weight of 1.280, they had a capacity of a content of about 30% finely divided metallic 100 ampere-hours and a service life of 400 ent-lead and 0.4 percent by weight of a sodium salt of the charges.

Carboxymethyl cellulose in the dry state intimately with- This example shows the volume-increasing properties

mixed together. This composition was in 40 shafts of the active material according to the invention, whether put into a mixer with the addition of 480 cm ^{3 of} water, probably no lead sulfate and no sulfuric acid in the addition, which is 176 cm ³ / kg; the mixture was used for 5 minutes composition of the paste. The mixed in order to play a pasty active mass further shows that the accumulators in which form. The paste had a density of 4.01 g / cm ³ and plates with the active composition according to the invention had a consistency of 9.6; it was turned into the grids, had a longer lifespan, and was pasted and dried. in their manufacture only a single-stage formation

For negative plates, 2722 g of black lead were required. With the one-step formation 2 percent by weight of the usual spreading agents, e.g. B. Soot, becomes twice the fill and twice the load over-barium sulfate and an organic lignin derivative, and liquid, which are generally used in the known lead acid-0.4 Percentage by weight of the sodium salt of the carboxy accumulators is used.

methyl cellulose in the dry state intimately with each other. It has been found that it is useful that

mixed. 420 cm ^{3 of} water, that is 154 cm ³ / kg, was added to the sodium salt of carboxymethyl cellulose in a concentration of this mixture and 0.4 to 0.7 percent by weight, based on the mixture, was permeated for 5 minutes. The corresponding paste had a density of the dry lead oxide material to use. The 4.34 g / cm ³ and a consistency of 14. It was pasted in and dried in Table II shows a list of numerous composition grids. gen active mass according to the invention and their own

These positive and negative plates were compared. Note that the application is using insulating separator in a housing with different percentages of hydrophilic substances a 6 volt accumulator of 100 ampere hours of ka- and the addition of various amounts of water to one capacity composed. 60 wider range of density and consistency of the

The cells of this accumulator were made with sulfur pastes.

acid filled with the specific gravity of 1.320. The compositions according to the invention of the active

The battery was operated at 13 amps for 30 hours. Another advantage of the material is that it is loaded. is that these compositions in mshr or

The accumulator was then dismantled for 65 less extensive thixotropic properties and checked. The surface of the positive plates was show. The paste consistency of the invention completely free of lead sulphate, which means that the complete composition can be extended through the mixing time Formation of the positive plates was indicated. The boundaries are changed. For example, it became a Acid electrolyte had a specific gravity of 1.270. Composition of Barton platinum with 0.4% An electrolyte with this specific gravity is 70 sodium carboxymethyl cellulose by adding

Table II

Active masses consisting of
Lead oxide and the following
hydrophilic substances

cm ^a

Water/

kg

Paste characteristics Consistency mm

density

g / cm mixing time

Condition of the accumulator

lifespan

Formation and time

Discharges

1. Sodium caxboxymethyl cellulose

2. Sodium carboxymethyl cellulose

3. Sodium carboxymethyl cellulose

4. Sodium carboxymethyl cellulose

5. methyl cellulose

6. Sodium Bentonite

7. Sodium salt of an ungelated

nated, low-substituted starch derivatives with a content of carboxylic acid and sulfuric acid groups

8. Sodium carboxymethyl cellulose

0.4

0.4

0.7

220 176 220 220 187 176

3.72 3.98 3.66 3.26 3.78 4.06

10
7.6
4.2
9

8 minutes

8 minutes
8 minutes
8 minutes
3 minutes

100%
90%

100%
90%

100%
60%

in 30 hours in 42 hours in 30 hours in 40 hours in 36 hours in 40 hours

548 513

2 0.4 *)

176

3 minutes

40% in 40 hours 100% in 24 hours

*) Example 8 is the only one that was treated according to the customary two-stage formation method.

220 cm ^{3 of} water per kg of composition formed. Depending on the length of the mixing time, this paste had the following consistencies:

consistency

Mixing time 3 minutes 4 minutes 15 minutes 16 minutes 8 minutes

13th

20th

21

After partial solidification on storage, the paste could become pliable again by appropriate treatment be made so that the desired consistency was achieved again,

The above example shows selected embodiments of the invention. The new invention active mass allows the production of accumulators that have a much longer life and the have the same initial capacity as the accumulators manufactured in a known manner. That in the invention The material used to increase the volume allows the production of lighter pastes, which results in a considerable saving in terms of lead content. While mixing the According to the invention, active composition does not generate any heat, and that when sulfuric acid is used any premature, irreversible solidification of the paste is no longer present here. Active matter pastes according to the invention can be accurate over a wide range of paste characteristics can be controlled, and in the event of an accidental mixing error, the desired density and consistency can be achieved by setting one or all of the variable parameters, namely the hydrophilic substance, the water and the mixing time. In addition, the use of the invention enables active mass a one-step formation and thus avoids unloading, refilling and the second Charge that are required for the plates with the material known and used up to now.

Claims (7)

PATENT CLAIMS: 1. Active mass produced with the addition of hydrophilic substances for pasting the grids of Lead batteries, consisting of an intimate mixture of lead oxide, a proportion of about 0.1 to about 2% by weight of a hydrophilic substance having a water absorbency of at least 20 g per g of hydrophilic substance and water. 2. Active composition according to claim 1, characterized in that a hydrophilic substance is used as the hydrophilic substance Cellulose derivative from the group of lower alkyl, oxyalkyl and carboxyalkyl ethers of cellulose is used, 3. Active composition according to claim 2, characterized in that the hydrophilic cellulose derivative is carboxymethyl cellulose is used. 4. Active composition according to claim 2, characterized in that the hydrophilic cellulose derivative is carboxymethyloxyethyl cellulose is used. 5. Active composition according to claim 2, characterized in that the hydrophilic cellulose derivative is methyl cellulose is used. 6. Active composition according to claim 2, characterized in that the hydrophilic cellulose derivative is oxyethyl cellulose is used. 7. The method for producing the active composition according to claim 1, characterized in that a Paste is formed from water and a dry mixture of lead oxide and hydrophilic substance in which the water in a proportion of 10 to 25 percent by weight of the paste and the hydrophilic substance in is present in an amount of 0.1 to 2 percent by weight of the mixture. Considered publications: German patent specifications No. 52 853, 82 798, 153139, 206,623; U.S. Patent No. 1,432,937; French patent specification No. 1 033 238. © 709 510/168 5. 57