NO753515L - - Google Patents

Description

Method and apparatus for produc-

position of battery plates

The invention relates to the manufacture of battery plates, especially of the tube type, and relates in particular to the filling of the tubes for such plates, a new apparatus for carrying out the method and a new material for paste of active material.

Tube sheets can be made from a range of different pipe materials and have a number of different pipe designs and can be made up of pipes which are connected to each other or formed as separate pipes which are separately placed on the skeletons or spines.

An example of such an arrangement of separated pipes is a pipe made of woven cloth with a thin, outer plastic sheath with perforations with a diameter of 1 - 2 mm and at a distance of 1 - 2 mm from each other. The piast mantle has a thickness of 0.1 - 0.2 mm.

The invention will, however, although not limited to such devices, be described with particular reference to tube devices where the tubes constitute a single pre-formed assembly, as this facilitates the assembly of the tubes on the spines of the plate.

A common method of making tubesheets involves impregnating cloth tubes with a resin to make them stiff but still permeable, placing the tubes on a series of lead alloy spines, with one spine for each tube, and filling the space between the tubes' interior and the spines with active material, e.g. lead oxide powder from a funnel, and shaking the assembly to compact the powder in the tube. This process presents considerable problems, including loss of lead oxide powder, uneven fill weight and uneven filling, and the active material tends to become too strongly compacted at the bottom of the tubes during the fill which forms the top of the tubes in use.

In British patent document no. 947 796, in order to reduce these problems, it is proposed to extrude a paste of active material containing a water-soluble thickening agent into the tubes under high pressure. However, this method leads to plates that have unpredictable, varying electrical properties. The paste is also prone to break down and lose its fluidity under pressure and also to solidify in the machinery if there were time gaps or delays during the production sequence.

In German specification no. 2 243 377 it is proposed to inject a measured volume corresponding to the inner volume of the tube plate of an acidic car accumulator paste. in the pipes within a very short time, e.g. under 1.5 s. The pasta contains a certain added amount of additional water. This is claimed to result in the formation of a suspension, but the mixture is in reality a thick paste which is not self-leveling. The described pastes contain 3 parts by weight of gray lead oxide, 1 part by weight of red lead oxide, 2.95 parts by weight of oxides per parts by weight of acid and water and 0.06 parts by weight of sulfuric acid with a specific gravity of 1.4 for each part by weight of oxide, i.e. 12.6% of the gray lead oxide was sulphated. It is described in the specification that the paste has a dynamic viscosity of 3000 - 4000 centipoise. There is no indication as to which method of measuring the viscosity or the measuring device to be used.

The inventors behind the present invention have measured the viscosity of the paste described in the German specification no. 2 243 377 using a viscometer with a rotating blade,

as described below using the measurement method described below.

It turned out that this paste had a torsion value (as defined herein) measured in a rotating blade viscometer of 10.595 kg-cm.' The paste is not self-levelling, i.e. when a mass is deposited as a lump on a flat surface, it does not obtain a flat leveled surface within 24 hours, even if small amounts of liquid separate from the solids during this time.

The method has the disadvantages that it requires a precise dosage of the paste volume to be injected and the paste has such a high viscosity that it has to be forced in. in the pipes below

high pressure.

This need to apply high pressure causes the paste to have a different specific gravity along the length of the tubes, and the paste tends to be too...strongly compacted at the inlet of the tubes which forms the bottom of the tubes during use. Moreover, known methods entail difficulties in getting the paste to penetrate over the full length of the tube, especially when using a deep plate. This implies a strong limitation of the size of the plate that can be filled. Thereby, further problems arise when producing accumulators from the paste and when using the accumulators.

According to the invention, it has been shown that these problems can be individually and collectively reduced by using a very different active material, an apparatus and a method where a • pourable liquid slurry with very low viscosity is poured into or fed into the pipes under the influence of gravity, after which when the pipes have been filled, it is preferably compacted by allowing the back pressure to build up. By regulating the value of the back pressure that is allowed to build up, the degree of compaction can be varied as desired and a very even compaction achieved.

According to the invention, the aim is to provide a method for the production of sheathed ~. mixture for active material with such a water content that active material is filtered out of the porous casing and a layer of active material is built up in the casing, the layer being built up from the end which is located farthest from the end through which the mixture is introduced' and back to the end through which the mixture is introduced, and liquid is emitted through the walls of the casing during the entire time that the layer is being built up.

The active material is preferably an active lead oxide material, and the weight ratio between solids and water in the mixture is preferably 2.5:1-0.4:1.

The term "sheathing" is intended to cover rows of separate tubes as well as rows of tubes which are interconnected or formed from sheets of material, as well as any sheath which will form a bag or pocket around the plate's current collecting element or elements and which effectively filters out active material in the form of a layer around the flowing element or elements.

According to a preferred embodiment of the present invention, this relates to a method for filling sheathed plates, preferably tube plates, for batteries, preferably lead/acid accumulators, where a mixture for active material is introduced into the porous sheath for a sheathed plate, e.g. the pipes, when the pipes are arranged on the plate's current-conducting element, e.g. the spines, and the method is characterized by the fact that the mixture for the active material is introduced into the casing in the form of an aqueous slurry when the casing is arranged in an essentially vertical plane, so that the solids can be deposited towards the bottom of the casing under the influence of gravity, and the aqueous slurry contains a weight ratio between active material and water of 2.5:1 - 0.4:1 and the material for the casing is chosen so that active material will be filtered out while liquids will be able to pass through, and as the solids are thus at least partially retained in the casing and the liquid at least partially passes out<i>through the walls of the casing, and the introduction of the slurry into the casing is continued until the casing is filled with active material, after which the pressure in the feed material to the casing is allowed to rise to above 0.35 kg/cm 2 , but not to more than 7.03 kg/cm 2 , and the pressure is then released.

To facilitate the description of the present method, this will be described essentially with reference to tube sheets.

The ratio between the slurry volume supplied to the pipes and the pipes' total internal free volume in the plates is preferably at least 2:1, more preferably at least 3:1, 4:1 or 5:1, preferably 5:1 - 15:1, and preferably 6 :1 -10:1.

The internal free volume of the pipes is the volume within the internal diameter of the pipes that is not occupied by the current-conducting elements.

The aqueous slurry comprises a mixture of water and particulate active material. The slurry may be free of added acid and it may be substantially free of sulfate. The weight ratio between solids and liquids in the slurry within the above-mentioned range that can best be used depends on the particular active material used and on the permeability of the pipes being filled.

The aqueous slurry preferably comprises a mixture of particulate active material, e.g. lead oxide, and water in a weight ratio of 0.5:1 - 1.5:1 or 2.0:1, preferably 1:1 - 1.8:1 or approx. 1.5:1.

A slurry with an oxide ratio of 0.1:1 had a specific gravity of 1.lg/cm , with an oxide ratio of 0.5:1 a specific gravity of 1.4, with an oxide ratio of 1:1 a specific gravity of 1.7 , with an oxide ratio of 1.5:1 a specific gravity of 2.15 and an oxide ratio of 2.0:1

a specific weight of 2.35 g/cm. The slurry preferably has a specific gravity of less than 2.5 g/cm<3>.

The solid particles in the slurry were such that less than 1% by weight thereof had a size above 200 um and less than 1% by weight thereof had a size below 0.001 um, incl. 95% by weight thereof with a size of less than 50 ym. These particle size-. see was determined using sieving.

With the non-woven fabric described below, it is preferred

to use ike-acidified slurries with a solid:liquid ratio of 2.0:1 - 0.5:1, e.g. 1.5:1-0.7:1.

With non-acidified slurries, it is more specifically preferred to use slurry mixtures containing gray lead oxide or red lead oxide or mixtures of gray lead oxide and red lead oxide containing up to 70% by weight of red lead oxide, and preferably mixtures of gray lead oxide and red lead oxide with a weight ratio of 66: 34 - 33:67.

With the spun-woven fabric described below, it is preferred to use non-acidified slurries with a solids:liquid ratio of 2.5:1, - 1:1.

With the woven cloth described below it is preferred

to use non-acidified slurries with a solids:liquid ratio greater than 2.0:1, e.g. 2.4:1 - 2.5:1.

The slurries that can be used according to the invention have viscosities that are essentially the same as for water, i.e. as compared to normal accumulator pastes and the pastes described in German specification document 224 337. The viscosity of the slurries according to the invention cannot be measured using a Brookfield -viscometer due to the fact that the solids settle out on standing.

Slurries that can be used according to the invention are easy to pour, and the solids separate quickly from the liquid phase, i.e. within less than 15 minutes when allowed to stand.

The mixtures are distinctive in that they have a torsion value (as defined herein) iv.measured with a viscometer with a rotating blade of less than 0.082 kg--cm, preferably not more than 0.055 kg-cm, at 20°C.

The suspension half-life (as defined herein) of the slurries is preferably no more than 15 minutes, preferably 1-10 minutes.

The slurries have viscosities which are essentially independent of the shear rate, i.e. they are not isotropic gels, and although the viscosities increase with increased shear rate, this drop is not predominant, and a gel is not formed when the shear force is removed.

The slurry may contain usual fillers and additives for the active material, such as hydrophobic or hydrophilic silicon dioxide, e.g. 0.1 - 0.5% by weight, based on the oxide. The introduction of the slurry into the pipes is preferably carried out under the influence of gravity, i.e. at zero pressure, or at a pressure of less than 0.35 kg/cm<2> until the pipes have been filled with the mixture, after which the pressure is allowed to rise to a value not exceeding 7 .03 kg/cm and the pressure is then released.

According to one device, the pipes are essentially filled by the influence of gravity, after which the pressure is allowed to increase to apply a pressure against the active material in the filled pipe in only a fraction of the time it takes to fill the pipe. The pressure can thus be 0.35 - 3.52 kg/cm<2>, e.g. 0.70 - 2.11 kg/cm<2>, used e.g. i l/.'^ tii 1/2 of the time it takes to fill the pipe, or a time equal to the time it takes to fill the pipe. The tube can thus require 5 - 15 s to fill, and the pressure can be applied for 1 - 5 s.

According to another embodiment, the pressure is applied for a longer time. In this embodiment, the pipes are essentially filled under the influence of gravity by the slurry being pumped into the pipes under a back pressure of zero, and as soon as the pipes have been filled, pumping is continued and the back pressure is allowed to build up to a value not exceeding 4, 92 kg/cm. The pressure can thus be '0.35 3.52 kg/cm<2>, e.g. 0.70 - 2.11 kg/cm<2>. The weight of the oxide in the tubes can be regulated by regulating the increase in pressure, as indicated in the examples. The pressure is usually only allowed to build up to one set value, and when this has been reached, the pressure is lifted.

It was surprising and contrary to the previous proposals where the entire filling is carried out under high pressure, which leads to the formation of layers in the active material as the paste has a higher specific gravity near the inlet, that with this embodiment the specific weight of the active material in the pipe can is increased evenly over the entire pipe without stratification occurring.

The pipe material is selected, as indicated above, so that it will filter the active material used. However, this does not mean that the entire amount of the active material is removed from the liquids emitted from the pipes, but only a relative amount of it is retained in the pipes.

As mentioned above, the ratio between active material and liquids to be used will depend on a number of variables, including the type of material from which the pipes are made.

There must be a balance between the need for the material to have a high permeability to water in order to achieve good conductivity when using the electric accumulator, and the need for the material to provide good filtration so that filling can be carried out quickly and the active material is retained in the pipes for a long time during use and when exposed to shocks and vibrations. A suitable material is made from a non-woven sheet of polyester fibers with a thickness of 0.5 - 0.7 mm and a weight of 120 - 160 g/cm, This is not perforated because its porosity is written from the different distances between the fibers of which it is made. It has a nitrogen permeability (as defined below) of 8.0 l/cm per minute and a water permeability (as defined below) of 1.5 l/cm 2pr. minute.

It is more generally preferred to use a material

with a nitrogen permeability of .0.5 - 20, preferably 1-10, or preferably 3-9, l/cm 2 per minute. It should preferably also have a water permeability of at least 0.01, preferably 0.1 or 0.5 to 1, 2 or 5, l/cm 2 per minute.

As indicated below, it is preferred to use a slurry mixture in which the particles of active material have an average size of 5 - 20 um.

A material with an average particle size of 1 - 30 or 50 or 100 um can, however, just as well be used, provided that the pipe material still has a sufficient filtering capacity. Active material with a larger particle size, such as a granular material, e.g. with a particle size of 0.1 - 1.0 mm can be used, and if desired, mixtures of active material with different particle sizes can be used.

The active material may be any desired for the: special electric batteries - to be manufactured, and although the invention is described with reference to lead/acid accumulators, the teachings set forth in accordance with the invention regarding the necessary requirements of the mixture for the active material and to the material for the sheath, whereby the filtration filling is achieved and a layer of active material is built up from the bottom of the sheath (the top in use), is applied to other electrochemical systems.

With reference to the lead/acid tanks, the lead oxide will preferably have particles, essentially all of which have a size of less than 100 ym, e.g. that less than 1% by weight thereof has a diameter of over 200 ym. Also, less than 1% by weight. hence particles with a diameter of less than 0.001 ym. Typically has at least 50% by weight, e.g. 9 5% by weight, of the particles with a diameter of less than

50 ym, 50% by weight has a diameter of less than 10 ym, and 5% by weight has a diameter of less than 1 ym. The oxide can be made up of a mixture

of gray lead oxide with an average particle size of

20 ym and red lead oxide with an average particle size of 5 - 10 ym. The ratio of gray lead oxide to red lead oxide can be 95:5 - 5:95, although 90:10 - 50:50, e.g. 33:67, is preferred.

The pipes are preferably clamped at the top and bottom so that the liquids can escape from the entire area of the pipes.

It is advantageous that a supply of the slurry mixture is continuously mixed during the filling and that a relatively smaller quantity of the slurry supply is introduced from this continuously mixed supply into each tube plate.

The supply of the slurry mixture is preferably dispensed by means of a pump which gives a uniform delivery and which keeps the slurry suspended, and in the spaces between the introduction into a tube plate the slurry is recycled from the pump's outlet back to its inlet, e.g. via a recirculation pipe that is connected to the pump's outlet, and a stirred storage tank from which a supply pipe runs to the pump's inlet.

According to a first embodiment of the present method, the slurry is introduced from a pump into a tube plate, and when this plate has been filled, the slurry is continuously recycled from the pump's outlet to the pump's inlet and then introduced into another tube plate.

The apparatus for carrying out the present method preferably comprises at least one filling station comprising a device for supporting the casing for a plate arranged on its flow end element in a substantially vertical plane, and a filling manifold which is arranged for introducing slurry into the casing for a plate arranged in the support device, the apparatus also comprising a slurry storage tank with a stirring device and arranged to contain a supply of slurry of active material, and a delivery device for delivering the slurry from the storage tank to the manifold for a selected filling station.

The delivery device preferably comprises a recycling device to recycle the slurry to the storage tank when the slurry is not delivered to a filling station..'

The delivery device may comprise a pump with an inlet pipe which is connected to the storage tank and a valve device, i.e. the circulation valve, which is connected to the pump's outlet for delivery preferably to a selected station, or when more than one station is used, to a selected station , or to recycle the slurry to the storage tank.

The device for supporting the plates is pre-

gradually arranged so that it will support tube sheets, and

t

comprises a frame which is rigidly attached to the filling manifold and which is provided with upper and lower clamps arranged to releasably clamp the plate to the frame.

The clamps can be provided with teeth and adjusted in relation to the outer surface profile for the bottom and top of the tube plate.

At least the upper clamp is preferably provided

with a compliant sealing liner.

The manifold is preferably adapted for use in connection with tube sheets, and is then preferably provided with an outlet nozzle device consisting of rigid filling tubes arranged at a distance from each other along a straight line with their centers on the centers of the tubes of the sheet and having outer diameters corresponding to the internal diameters for the plate's tubes. The pipes are thus preferably vertically arranged so that the slurry fills the pipes under the influence of gravity.

The supply pipes can run through a resilient gasket, and the dimensions of the frame in relation to the plate are such that the end of the plate must be forced up into the gasket to place the plate in the support device.

A pressure-sensitive valve is preferably arranged so that it. is in connection with the inlet side of each filling mainfold.

Preferably at least two are used. filling stations for each pump and slurry storage tank, and the recirculation valve is a three-way valve.

The pressure-sensitive valve or each pressure-sensitive valve may be so arranged that it will automatically affect the setting of the recirculation valve or of the valve assembly connecting the manifold or each manifold to the common supply line, to its recirculation position, and so as to relieve the pressure against the plate immediately in advance certain pressures have been reached.

The pump preferably comprises a rotor in the form of a single starting spiral armature in a cylinder in the form of a double-starting spiral with twice the pitch of the rotor, where the rotor rotates around its own axis in one direction while its axis rotates around the axis of the cylinder in the opposite' direction at the same speed.

According to a further embodiment of the invention not

the present method is limited to the filling of sheathed tube sheets. Other wrapping forms can thus be used, e.g. envelope-shaped enclosures, and in this case the grid does not have to be a comb of spines, but can be made of a normal cast grid or of a net-shaped plate, e.g. a metal sheet or sheet with punched-out openings, and it can even be made up of a solid sheet if necessary

ge current collection function is carried out satisfactorily.

The sheath can be made of a flexible material or of a rigid material, but at least when the sheath is flexible, it is preferred to support its surfaces with porous support devices, e.g. rigid, perforated plates, tablecloths or grids, during filling to thereby hold the sides of the plate

essentially parallel, while the fluids can pass through.' the plate.

With this device, the inlet manifold must also change

res so that instead of a row of tubes forming plugs at the ends of the casing's individual tubes, a single or double tube slot is arranged to form a plug at the open lower end of the casing.. A double slot device extending over the end of the grid and providing a pair of slits extending along each side of the grid qg can be clamped to this can offer advantages compared to a single slit device.

The end of the casing can be sealed with a long bottom bar or infill. This can consist of an internal plug that stands

in engagement with the end of the grid, and by an outer clip or an integral flange on the plug which is adapted to engage.

grasp the underside of the casing and hold it against the plug.

According to another embodiment, retractable filling pipes that extend down into the casing can be used instead of an inlet manifold with fixed pipe outlets or fixed slots.

With this device, the filling pipes will first extend completely

down into the casing around the spines (which now do not need to have centering fins as the filling pipes perform this function). After the active material emerges from the ends of the tubes, the tubes are drawn back up along the sheath and finally stop at the open upper end of the sheath where they can be instantly clamped and then released to completely fill the plate.

However, this device is clearly more complicated

than the device where the slurry is simply introduced at the top of the tubes, and this simple device is far preferred.

The invention can be practiced in various ways, and

two special embodiments with certain changes will below-

to be described as an example with reference to . the drawings, of which

fig. 1 is a schematic side view of an embodiment

of an apparatus according to the invention,

fig. 2 is a schematic perspective sketch on an enlarged scale of the filling box shown in fig...1,

fig. 3 is a schematic view of a part of that in fig.

2 showed the lower clamp in the open position, and where only part of the plate's tube is shown,

fig. 4 is a horizontal cross section taken along the line

IV - IV in fig. 3,

fig. 5 is a partial cross-section through part of the upper clamp in the open position, as shown in fig. 3,

fig. 6 is a general front elevation of the viscometer

with rotating blades used to measure the viscosities of the slurries used according to the invention,

fig. 7 is a detailed front elevation of the vane assembly for that of FIG. 6 displayed viscometer,

fig. 8 is a horizontal view of the container to be used together with that of fig. 6 showed viscometer for receiving

look at the sample whose viscosity is to be measured,

fig. 9 is a horizontal view based on a photomicrograph. fi of the non-woven fabric described below that is used in the examples,

fig. 10 is a front elevation of a preferred embodiment of a satellite filling station for use in connection with another embodiment of the invention, where slurry is supplied from a central preparation station for slurry to a number of satellite filling stations,

fig. 11 is a side view of the one in fig. 10 shown sate-littif yllningsstation,

fig. 12 is a horizontal view of the one in fig. 10 showed

satellite filling station,

fig. 13 is a horizontal view of the central one

station for preparation of slurry mentioned above in connection with fig. 10,

fig. 14 is a side view of the one in fig. 13 displayed station,

fig. 15 is a front elevation of a preferred embodiment of the filling manifold and the upper clamp as used in connection with the one in fig. 10 showed filling station,

fig. 16 is a horizontal view of the one in fig. 15 showed filling manifold,

fig. 17 is a cross-sectional view taken along the line XVII - XVII in fig. 15,

fig. 18 is a front elevation of a preferred embodiment of a bottom clamp as used in connection with the one in fig. 10 showed a filling station, and

fig. 19 is a vertical cross section taken along the line

XIX- - XIX in fig. 18.

The apparatus consists of a slurry tank 10 in which the slurry to be filled in the plate pipes is stored. The tank is provided with a stirring paddle 11 arranged at the bottom of the tank and which is driven by means of a belt and drum drive device 12

which is driven by means of a motor 13 with variable speed.

A vertical supply pipe 15 extends upwards from just above the bucket 11 to the inlet for a supply pump 16 which is also driven, by means of a belt and drum device 17 which is driven by a motor 18 with. variable speed. The outlet of the pump 16 is vertically downwards in connection with a plate filling station 20 by means of a supply line 19. The supply line runs through a manometer 22, a two-way valve 23 and a fishtail manifold 24. The valve 23 is adjusted so that the slurry can flow vertically downwards to the station 20, or it is set so that the slurry will be led to the tank 10 via a recirculation pipe 26 which projects downwards to just above the stirring paddle 11. The pipes 15 and 26 preferably have the same cross-sectional area.

The quantity of the slurry supply is preferably kept at approx. 150 kg, or more generally of 100 - 200 kg, and the amount of slurry introduced into each tube plate, i.e. the individual filling weight, is 400 - 1000 g. The weight ratio of active material, e.g. 75 kg in the continuously mixed slurry feed in relation to the individual fill weight is more generally 200:1 - 25:1, e.g. 160:1 - 100:1.

The station 20 comprises a frame 29 which is rigidly fixed in relation to the manifold 24 and which has upper and lower clamps 30 and 31.

The clamps 30 and 31 are provided with teeth and adjusted in relation to it. outer surface profile of the bottom and top of the tube plate, as the plate is inserted into the clamps with its open bottom facing the manifold 24. The manifold has an outlet nozzle device consisting of 6.35 mm long copper tubes or other rigid supply tubes with outside diameters corresponding to the inner diameters of the plate tubes and which are arranged at a distance from each other along a straight line, the centers of the supply pipes being located. on the centers of the plating tubes,

in

The open ends of the plate pipes thus fit tightly over the supply pipes and are attached to these by means of the upper clamp 30 which can be provided with a flexible sealing liner.

The lower clamp 31 holds the plate in position and presses the tubes against a thickened end section of the spines. The plate's surfaces are completely free.

The spines are made of a common lead alloy and have a common design and are arranged on an upper rail at centers that correspond to the centers of the tubes with which they will be used. They are preferably provided with short axial fins which are used to center the spines in the tubes and to prevent the spines from becoming. distorted during handling before 'filling.

The station 20 will now be described in more detail with reference to fig. 2-5.

As mentioned above, the station 20 comprises a frame 29 which is rigidly fixed in relation to the manifold 24. This frame is divided into two parts 32 and 33 which are hingedly connected to each other along the left edge/and it is the part 33 which is rigid attached to the manifold 24. ~ The upper and lower clamps are both in two parts 30A .and 30B and 31A and 31B..The parts 30A and 31A are supported by the movable part 32 of the frame 29, and the parts 30B and 31B are supported by the fixed part 33 of the frame 29 .

The attached part 33 is also provided with upper and lower locking bars 36 and 37 which are arranged for engagement with upper and lower handles 38 and 39 on the movable frame part 32 and keep the filling station closed.

The attached part 33 of the frame 29 also carries a lower support rail 42 with an opening 43 through which a cam 44 on a plate 45 can pass and which helps to place the plate in the correct position on the filling station.

The upper and lower clamps 30 and 31 have a toothed profile

which are matched in relation to the outer, enveloped dimensions of the plate, and the two parts of each clamp delimit in the closed state a row of cylindrical holes 4 8 which are connected to each other by means of slots 49 with a thickness that is twice as thick than the wrapping cloth's 47, thereby preventing the wrapping from being cut into pieces by the clamps.

The lower clamp 31 presses the wrapping cloth 47 against the wider shoulders 51 of the plate's safety rows 52 to achieve a tight seal (see fig. 3 and 4).

In fig. 5 shows the clamping arrangement at the manifold 24. A manifold plate 54 is provided with a row of supply pipes 55 which extend downwards through the manifold and have tapered ends 56 which protrude through openings in a rubber packing ring 58.

flexible and can be compressed by finger pressure to only approx. half of its thickness.in the uncompressed mixture which is approx. 3.18 mm. In fig. 5, the casing 4 7 is shown placed over the ends 56 of the supply pipes. However, this arrangement is in reality such that the gasket 58 must be pressed together approx. 1.59 mm of the jacket 47 which is forced up into the gasket, so that the plate's Upper. rail must be placed on the frame's lower rail. 42 (This compression is not shown in the drawing). The clamp 30 presses the wrapping cloth 47 around the ends 56 of the supply pipes 55 to achieve a good upper seal. The pipes are then filled while vertically arranged and with their upper rail at the bottom.

The pump 16 provides an even delivery and is of the well-known

tea type, such as is sold under the trademark "MONOPUMP", which comprises a rotor in the form of a single-start spiral armature in a cylinder in the form of a double-start spiral armature of twice the pitch of the rotor, and in which the rotor rotates about its own axis in one direction while its axis rotates around the axis of the cylinder in the opposite direction at the same speed. This pump-

type provides a positive displacement with uniform flow and prevents

that liquids and solids separate from each other in the slurry.

According to another embodiment (not shown), the filling station 20 is formed with a twin manifold arranged, each manifold being filled by means of the pump 16. The two-way valve 23 is replaced by a three-way valve, and each line from the valve 23 to a manifold contains a pressure sensitive valve 70.

This valve 70 is preferably a pressure reduction valve which can be set to any desired pressure, e.g. 1.05 kg/cm2,, and which, once this pressure has been reached, will maintain the pressure of 1.05 kg/cm2 until operated, e.g. manually.

The procedure that will then be followed is that a plate is introduced into a manifold and that the position of the valve 23 is changed from recirculation or from the other manifold. The plate will be filled e.g. during 5 s and then the pressure will be increased to 1.05 kg/cm 2 and maintained for 5 s. During this time the operator will have removed the filled plate from the second manifold and inserted a new plate. He can then change the position of the valve 23 for immediate recirculation or to immediately fill the new plate.

According to another embodiment, the pressure reduction valve 70 is arranged in such a way that the pump supply will change to recirculation and cancel the pressure against the plate as soon as the predetermined pressure has been reached.

The filling process is carried out in practice as follows.

The slurry is prepared with the desired composition in the tank 10 using the stirring paddle 11. A pipe plate 50 is mounted, the non-woven fabric pipes 47 are placed on the metal spines 52, and the plate is brought against the clamps 30B and 31B on the station 20

with its open lower ends pushed up against the gasket 58 and over ends 56 of the manifold 24 supply pipe 55. The frame part 32 is then swung close to the part 33, and the clamps 30 and 31 are thereby closed and the locking rods 36 and 37 are fastened over the handles 38 and 39. The pipe scoop 11 is kept in operation, and the valve 23 is set in the recirculation position so that the pump 16 is connected to the pipe 28, and the pump 16 is started. Recirculation - is carried out until the current has become steady. The pressure indicator 22 indicates zero pressure while the recirculation is taking place.

The valve 23 is then changed to the position where the pump 16 will be connected to the manifold 24. The slurry flows down through the station 20, and part of the active material will be separated inside the pipes, while excess liquid and active material is drawn off through the pipes' fabric 47 and back to the tank 10. The valve 23 is held in this position until the pipes have been filled with active material, and at this point the pressure indicator indicates a relatively sudden increase in pressure. The valve 23 is then set in the position where the slurry will be recycled to the tank 10 via the line 26.

The clamps 30 and 31 are then opened, and the filled plate is removed and the plate is subjected to the further treatments, such as the introduction of a bottom rail, pickling, drying and electrolytic multiplication.

The excess of slurry in the manifold 24 falls down

in the tank 10.

During continuous operation, the pressure increase indicated by the indicator 22 can be used to regulate the filling cycle, e.g. to actuate the valve 23 and open the clamps 30 and 31 to release them from the manifold 24 and to introduce a new plate in the clamped position. Limit switches can be used which can be affected by the new plate which engages with the manifold 24,

to shift the valve 23 back to the filling position.

In the embodiment shown in fig. 10 - 19, two or more are added, e.g. three, satellite filling devices, as shown in fig. 1-5, slurry from a central slurry reservoir and from a replenishment tank which is arranged on a scale so that it can be continuously weighed. The reservoir is continuously stirred and supplied with a float-regulated water supply to keep the slurry volume constant. The slurry initially has an oxide:water ratio of 1.5:1. Each satellite filling device is supplied with a slurry by means of a variable speed pump. As soon as the reservoir quantity has fallen by 544 kg and the oxygen:water ratio to 1.2:1, the pumps to the satellites are closed. 362.9 kg of red oxide and 181.5 kg of gray oxide are added. The ratio bxyd:water in the satellites falls to approx. 1:1 while doing this. When the supply from the reservoir to the satellites is restarted, the solid:liquid ratio is restored.

With this device, it is preferred to increase the volume of the tank 10 in the satellite filling device so that when the supply from the main tank is shut off during refilling, the oxygen: water ratio will not drop too much. The amount of slurry is thus preferably 500 - 625 kg, and the weight ratio between the active material in the slurry and the individual filling weight (e.g. 200 - 1200 g) is thus 1300:1 - 200:1, e.g. 1000:1 - 250:1. The mixing of the slurry continues in the reservoir during the oxygen addition, and as soon as this is finished, the pumps for the satellites are started again.

The central station 100 for making slurry is shown in fig. 13 and 14. The preferred embodiment of the satellite filling apparatus 130 is shown in fig. 10 - 12 and 15 - 19.

Three such identical filling devices 130 are preferably supplied with a slurry from the central station 100 by means of a supply line .101 under pump pressure and a return line 102 under pump pressure or by the influence of gravity.

The central station comprises a circular slurry tank 103 which is arranged on a bottom plate 10-4 via a weight cell 105 and a pair of transverse spring suspensions 106. The weight cell and the suspensions are placed at the corners of an isosceles triangle. A vertical stirring paddle 107 is arranged for rotation about a vertical axis in a horizontal plane at the bottom of the tank 103 and is driven by a motor 108 to keep the solids suspended in the tank 103. The tank has a lid 109 with a shielded opening 110 (not shown) through which a powder supply mechanism 111 can tip powder into the tank 103.

The powder supply mechanism 111 consists of an elevator 112 with a cradle 113 which can engage a drum 114 of active material and lift this up and around a circular path and tip this into the tank at the position 115 shown by means of dash-dotted lines on fig. 14. The mechanism 111 is surrounded by a screen 116 as indicated by dash-dotted lines in fig. 14. The tank 103 is kept filled with water using a ball valve 117.

The preferred embodiment of the filling apparatus as shown in fig. 10 - 12 will now be described in more detail. This closely resembles the general embodiment of the apparatus shown in fig. 1 - 5, and the same reference numbers will be used for the same parts.

The slurry tank is thus provided with a stirring paddle 11 arranged at the bottom of the tank and driven by means of a motor

13 with variable speed via a gearbox 131. A vertical

supply line 15 with a filter at its lower end extends upwards from just above the mixing paddle 11 to the inlet for a supply pump 16 of the "MONOPUMP" type which is driven by a motor 18 with variable speed.

The outlet 132 of the pump 16 is connected to a common supply line 133 which extends past a pair of inlet valves 134 and 135 to a pair of filling manifolds 136 and 137 and to a recirculation line 138 which extends down into the

the naughty tank 10.

The valve 134 is regulated by a pneumatic cylinder 141 and a crank 14 2 and is arranged in such a way that it will always be open to the manifold or to the by-pass. The valve 135 is arranged in a similar way. The valve 135 is regulated by a similar cylinder 143 and crank 144.

The valves 134 and 135 are used for supply to the manifolds 136 and 137 via the lines 146 and 147 which extend. up from the valves to the manifolds so that any deposits in these lines will tend to occur in the area of valves 134 and 135 and can be easily flushed out. The pressure gauges 148 and 149 are placed in the lines 146 and 147 and are provided with pressure cut-off devices so that as soon as the pressure in the lines 146 or 147 reaches a predetermined value, which can be determined as desired, the cylinder 141 or 143 is automatically affected, and the supply from the pump is switched over to the bypass line and returned to the tank 10 via the lines 133 and 138.

The cylinders 141 and 143 are also arranged so that they are controlled by switches which are affected by a door 150 (although it can be bypassed if desired). When the door is closed over a manifold, e.g. 15.1 on fig. 12, the valve 134 is changed from the by-pass position to the supply position, and the slurry is supplied to the manifold 136. When the pressure rises and is shut off, the door can then be swung to the other side to actuate the valve 14 3 for the second filling manifold 137.

The filling manifolds 136 and 137 are connected to bottom clamps 152, only one of which is shown in fig. 10 to make the drawing easier. The manifolds and bottom clamp are placed on a support plate 155 (see fig. 11) which leans backwards at a small angle in relation to the vertical, so that it is easy to put the plates in place, in the clamps and to prevent the plates from falling out sooner. the clamps are closed.

The filling manifolds. is shown in more detail in fig. 18

and 19.

According to fig. 15 - 17, the manifolds consist of a manifold main part 160 which was bolted to the mounting plate 155 and which provides a rectangular, horizontal slurry distribution cavity 161 to which the slurry is supplied from the rear through a central opening 162 to which the line 146 or 147 is connected. At the center of the upper surface of the cavity 161 is an opening 163 in which the pressure gauge 148 or 149 is placed.

A row of nozzles 167 extends downwards from the lower surface of the cavity 161 and out through the main part 160, and it is over these short nozzles that the cloth tube is brought up and to which it is clamped. The clamping is achieved by means of a movable front clamping surface 170 which is carried in a frame 230 which is attached to the main part 160 by means of vertical bolts 171. The inner surface of the clamp is made up of a series of rounded teeth, as shown in fig. 5, but the teeth are chamfered as shown at 172 in fig. 17 . '

The front clamp 170 acting by a movable rear clamp 175, and the two clamps are actuated by a pair of pneumatic cylinders 176 which are arranged on the piston attached to the front clamp 170.

The cylinders 176 are attached to the rear clamp 175, and when actuated to force out the pistons 177, they will thus drive the clamping surface 175 backwards towards the support plate 155 and at the same time drive the front clamp 170 forward. The distance thus covered can be varied using the adjustable stop nuts 178. The clamp 175 has a round, toothed upper edge 180 which clamps the rear edge of the cloth against the nozzles 167, and this edge 180 is also slightly beveled , as shown in fig. 17. The clamp 175 also has a grooved skirt 181 to facilitate placement of the plate in the clamp. The plate can thus rest against the skirt 181 in the correct grooves and then slide. upwards into the clamp. ,

In fig. 18 and 19, the bottom clamp 152 consists of a back frame 190 which is bolted to the support plate 155, but separated from this by means of a spacer 191 so that liquids coming from a plate in the clamp can flow downwards behind this. ■ A pair of side flanges 192 are bolted to the back frame 190, and a front frame 193 is hinged to these flanges by means of pivot pins 194. At least one of the flanges also carries a stop nut 195 to prevent the front frame 193 from moving more than 90° from the closed position. The front frame is held in the closed position or in the open position by means of an over-centered link from these through an overflow line device 231 which is in connection with the return line 102.

The weight of the slurry in the tank 103 is measured continuously or periodically by the weight cell 105, and when it has fallen to a predetermined value, a warning signal is given to the operator.

The slurry in the tanks 10 is continuously mixed and pumped by means of the pump 16 through the circuit: line 15, pump 16, line 132, valve 134 set for bypass, line 135 set for bypass and line 138.

A plate comprising fabric tubes arranged on the conductive spines and of suitable dimensions for the upper and lower clamps used is placed in a filling manifold, e.g. 136, and , the upper and lower clamps are tuned. The door 150 is now closed, and if the automatic device is used, the cylinders 141 change the position of the valve 134 so that the pump 16 is connected to the manifold 136. The plate is filled, the pressure in the manifold cavity 161 increases and at the predetermined value affects the pressure gauge 148 which in turn affects the cylinder 141 which changes the position of the valve 134 back to bypass.

As soon as the door 150 had been closed, the operator could have put another plate in place in the manifold 137. As soon as the first plate has been filled, he can thus start filling the next plate before or after the first plate has been removed. The cycle can be continued until the main tank 103 needs refilling, and this can, if necessary, be carried out by another plant operator.

At the end of a shift or when the filling station is to be left behind, it is important that the slurry is pumped from tank 10 back to tank 103 and that the filling station is cleaned carefully and its line flushed with water.

For the description of the preferred embodiment of the invention, it has been shown to plates which are filled in an essentially vertical plane, and although according to fig. 1-5 the plates are filled while they are vertically arranged, the plates, as shown in fig. 10 - 19 and on fig. 11, are just as well filled when they are arranged with an angle of approx. 5° in relation to the vertical plane.

It will therefore be understood that as long as the layer of active material can be built up evenly from the end furthest away from the inlet end and the space between the backbone and the sheath is sufficiently evenly filled on both sides so that it will not exceed the electrical properties, is the exact angle that the plate has when the filtration filling takes place, not of decisive importance.

Although it is thus clearly important that the plates are held in place with a large angle of inclination, there is considerable leeway for variations. The angle will clearly vary depending on the length and diameter of the plate and the size of the spine. A very narrow, annular space is thus filled, and as long as the largest horizontal distance from side to side above the inclined pipe is not

several times, e.g. not more than 10 times, the smallest transverse dimension of the pipe or casing, it can be expected that no . significant adverse impact on the uniformity of the filling will occur.

It may therefore generally be possible to fill the pipes when

■they are inclined at an angle of as much as 60° to the vertical plane, although angles of up to only 20° to the vertical plane are probably better.

In terms of the device, the invention relates to a number of further embodiments.

According to an alternative embodiment, there are thus arranged at least two filling stations for each pump and slurry storage tank, and the manifolds are supplied with the slurry from a common supply line which connects the pump's outlet with the recycling line., and valve devices are used to selectively connect each manifold with the supply line.

According to another embodiment of the present apparatus, the upper clamp comprises a fixed, toothed surface and a movable, cooperating, toothed surface which is adapted to be moved away from the fixed surface while remaining parallel to it, by means of pneumatic or hydraulic devices. Also, to facilitate the flow of liquid from the pipes, at least one, preferably both, of the opposing surfaces of the lower edge of the upper clamp or the upper edge of the lower clamp, or preferably both clamps, are chamfered.

The rear surface of the upper clamp carries, preferably, a slotted part which hangs down therefrom to facilitate the placement of a plate in the clamp.

According to one embodiment of the present apparatus, the lower clamp has a front clamping surface hingedly suspended from a rear clamping surface, and biasing devices are used to force the front plate to a closed position or to a fully open position.

The invention also relates to a plant for filling sheathed accumulator plates, comprising a central station for manufacturing and slurrying and at least one filling apparatus in accordance with the previously described embodiments of the invention, and a device for supplying slurry from the central station to the filling apparatus.

The device for supplying slurry preferably includes a device for continuous supply of slurry to the filling device or each filling device and a return device for returning slurry to the central station so that the slurry can be continuously circulated.

The slurry production station preferably comprises a tank, a weighing device for weighing the tank, a stirring device for keeping the slurry suspended, and a supply device for active material and a supply device for liquid.

The weighing device preferably comprises a weight cell

arranged under the tank.

The stirring device preferably comprises a paddle which can rotate at the bottom of the tank. The invention also relates to a method using the plant, where slurry is continuously supplied from the central production tank to each filling device and back to the central tank in such an amount that the contents of the filling device's slurry tank are replaced at least every hour, preferably at least every half hour, and preferably every 5-15 minutes.

According to another embodiment (not shown), the three filling devices are arranged around the central station for making slurry, instead arranged along a straight line with the central station at the end of the line or on the line between neighboring filling devices. Up to six filling devices can be supplied with slurry from a central station. The supply line 101 and the return line 102 are both supplied in this case

slurry from a pump, e.g. a "MONOPUMP", and may be made of a stocking or wire with an inside diameter of 1 inch.

The viscosities stated herein are used to characterize the slurries as easily pourable and with low viscosity. The viscosities given in Tables 4, 7, 10 and 15 are the observed viscosities and not the torsion values (as defined herein) used to characterize the preferred slurries. It will be understood that in order to convert the observed torsion values according to Tables 4, 7, 10 and 15 to the torsion values (as defined herein), the background value of 0.055 kg-cm must be subtracted from the observed values. Certain examples, e.g. 2 and 24 in table 4 and 17, 26 , 34 , 54 , 55 and 56 in table 15,. have values that are the same as the background values. Their observed torsion values are thus not greater than the background value for the measurements carried out, and they satisfy the preferred viscosity characteristic that they have a torsion value (as defined herein) of less than 0.083

. kg-cm at 20° C.

An example will now be given of a particular method of producing a plate. This example was carried out using the apparatus described with reference to fig. 1-5.

The plates were positive plates with fifteen tubes each with a length of 22.9 cm. The tubes were made of non-woven polyethylene terephthalate fibres. These are made as follows: A thin web (1.5 m wide) of fibers with an average length of 11.4 cm is produced by carding, and a fur . produced by adding approx. 10 webs on top of each other to produce a continuous web of non-woven cloth (also with a width of 1.5 m).

The fibers generally extend along the web which is pleated in a zig-zag pattern as it is removed from a conveyor running in the same direction as the length of the web and to a conveyor running at right angles to the length of the web . The fibers thus extend essentially across the longitudinal direction of the fur, but due to the direction of movement of the second conveyor, the fibers in the neighborhood are oppositely inclined at a small angle in relation to the transverse direction.

This material is then impregnated with 50% by weight of a polyacrylic binder. It has a thickness of 0.5 - 0.7 mm and weighs 120 - 160 g/cm<2>

This material is then converted into a series of tubes by passing two layers of the material through a multi-stitch machine to fasten the layers together along parallel lines (eg spaced 2 per 2.54 cm apart) to form pockets or .stir in the usual way.

This material is then dipped into a phenolic resin and dried. The material absorbs 30% phenolic resin, based on the dry weight of the unwoven material. After dividing the material into proper lengths, circular mandrels with a diameter of 0.729 cm are inserted between the rows of stitches to form the pockets. The material has an air permeability of 8.0 l/cm<2>per minute and a water permeability of o 1.5 l/cm 2pr. minute. Its structure is shown in fig. 9.

It appears from fig. 9 that this non-woven cloth is made of arbitrarily entangled single fibres'. The fibers have a diameter of approx. 25 ym, or more generally 20 - 50 ym. The distance between the individual fibers is usually below 250 ym, and as a rule below 100 ym, and as the material also has a thickness of 0.5 - 0.7 mm, it has a three-dimensional structure that enables the overlapping of a number of individual fibers along any path from surface to surface of the plate. The material has an excellent filtering ability for use in carrying out the present method as, although in the form of a tube it enables the passage of both liquids and solids, it quickly fills with active material when this is added to or poured into the tubes under the influence of the weight.

Air permeability was measured as follows:

A sample with a diameter of 2.8 cm (an effective cross-sectional area of 6.16 cm<2>.) was clamped, and the time it took for 50 L of dry nitrogen to flow through the sample at 20° C under

a pressure difference of 1.5 cm water column was noted.

The material is too permeable for the use of mercury porosimetry or measurement of the air flow through an alcohol-saturated sample to be accurate measurement methods.

However, air permeability is known to accurately indicate a material's filtering ability, and materials suitable for carrying out the present method can thus be selected by measuring their air permeability.

The water permeability was measured for the same sample by measuring the time it took for a column of water with an initial height of 4 2 cm and a volume of 1 liter to flow through the sample under the action of gravity.

The downstream end of the column below the sample was closed, the water network was introduced over the sample, and the downstream end below the sample was then opened to the atmosphere.

The slurry used in this example 1 was made from a mixture of 1 part by weight of gray lead oxide (with an average particle size of 20 ym) and 2 parts by weight of red lead oxide (with an average particle size of 5 - 10 ym) mixed with tap water in a weight ratio of 1 ,5:1.

The tank 10 contained 150 kg of slurry, and the stirring paddle 11 with a size of 76.2 x 3.8 cm was rotated with 30 - 70 revolutions per minute. minute (rpm) to keep the solids suspended. The pump 16 was set to a volume capacity of 9.5, or more generally 4-10, l/min., and during the recirculation the pressure indicator 22 showed zero pressure. Using the same stirring and pumping conditions, the valve 23 was set in the filling position. The indicator 22 showed zero pressure for 5 s, and 1.05 kg/cm<2> after a further 1 s, when the valve 23 was again set in the recirculation position. The internal volume of the tubes was 105 cm 3.

The volume of the slurry that passed through the plate was 0.8 1, i.e. the ratio between the volume of the slurry and the internal volume of the plate was 1.6:1.

Flow rates of less than 4 l/min. proved to give relatively slow filling rates, and this reduced the production capacity of the process, while flow rates of over 13 l/min. using these special cells proved to give relatively low filling weights for the plates.

-While the slurry is thus introduced into the upper ends

of the tubes, these are filled up from the bottom, an oxide layer is built up evenly in the tube, and water and partial oxides come out through the tube cloth mainly, at the level of the upper surface of the active material in the tube. However, liquid is also released over the total filled length of the pipe, and it is assumed that additional liquid is forced out over the total length of the pipe as soon as the back pressure begins to increase.

The plate was then dried. The plates were weighed, and the weight was 450 + 20 g. The plates were then stained in the usual way. A . Large numbers of plates were produced in this way. Some were cut open and weighed, and there was no significant weight variation between the top, middle and bottom of the tubes. For other plates, the electrical properties were measured and compared with plates shaken with dry powder using the same active material. These plates were designated as standard plates.

The plates produced according to the present method had essentially the same discharge duration at the first and also at the tenth discharge by a standard charge/discharge method in the same way as the standard plates.

Plates with separated tubes with internal volumes of 50 - 250 cm 3 can be easily filled.

However, it has been shown according to the invention, mentioned . above, that the degree of compaction and thus the total dry fill weight for the pipes can be regulated by regulating the pressure that is allowed to build up at the end of the filling period.

It has thus been shown, using the same slurry and the same tubes as described above, that if the pressure is only allowed to rise to 0.35 or 0.49 kg/cm2, the weight becomes 420

g + 5%. If the pressure is allowed to rise to 1.05 kg/cm 2 , the weight becomes 450 g + 5%, and if the pressure is allowed to rise to 2.46 kg/cm 2 , the weight becomes 500 g + 5 %.

Moreover, the pipes are still evenly filled without stratification when using these filling weights.

The active material in the tubes at a fill weight of 450 g has a specific gravity of 4.3 g/cm.

When this example was repeated using a paste of 3 parts by weight of oxide per 1 part by weight of water (as the pastes had a specific gravity of 3.5 g/cm 3 ), the material was essentially extruded into the tubes which were filled in less than 1 s. No significant amount of liquid passed out through the tubes, and at examination, the plates had a significant layer formation due to the self-weight in the pipes.

Example 2- 27

These examples were carried out using that in connection with fig. 1-5 described apparatus and using the method described in example 1.

The tubes were made in the same way as described for the non-woven tubes according to example 1, but with the exception that they had a length of 36.8 cm instead of 22.9 cm.

The tubes of non-woven fabric according to example 1 were used for certain of the examples, as indicated by the letters N-W in the following tables IA and IB and 2A and 2B. Two other cloths were also used.

One was a spun-woven cloth, designated S.W. in

the tables IA and IB and 2A and 2B below, and had an air permeability (as defined herein) of 6.0 l/cm 2 per minute. It had 18 weft threads per cm and 22 warp threads per cm. The warp threads had a diameter of approx. 250<y>m and the weft threads a diameter of approx. 375 etc. An examination under the microscope showed that the distance between neighboring warp threads and neighboring weft threads was approx. 250 ym x 250 ym, but these distances were crossed by bridges of a large number of loose fibers protruding from the threads. It. effective filtering capacity of the fabric is thereby greatly improved.

The other cloth was a woven cloth designated by W. in the following tables IA and IB and 2A and 2B, and had an air permeability (as defined herein) of 15.2 l/cm 2pr. minute.

It had 18 weft threads per cm and 22 warp threads per

cm. The warp and weft threads had a diameter of approx. 250 etc. An examination under the microscope showed that the distances between neighboring warp threads and neighboring weft threads were approx. 250 ym x .250 ym and that they were not crossed by fibers protruding from the threads. The filtering capacity for this fabric was thus far less than

for the spun-woven cloth..

The materials used are listed below

tables IA and IB and 2A. and 2B.

The slurry was made from mixtures of gray lead oxide (with an average particle size of 20 ym) and red lead oxide (with an average particle size of .5 - 10 ym) mixed with tap water in various weight ratios.

Of the solid particles in the slurry, less than 1% by weight had a diameter of over 200 µm, less than 1% by weight had a diameter of less than 0.001 µm, and 95% by weight had a diameter of less than 50 µm. These particle sizes were determined by sieving.

The tank 10 contained 150 kg of slurry, and the stirring paddle

.11 with a size of 76.2 x 3.8 cm was rotated at 30 - 70 rpm to keep the solids suspended.. Pump 16 was used with different volume capacities, as indicated in Tables IA and 2A. During recirculation, the pressure indicator showed 22 zero pressure. Using the same stirring and pumping conditions, the valve 23 was set in the filling position, and the time when the indicator 22 showed zero pressure was noted, and the total time until the valve 23

again was set in recirculation position and the highest pressure reached, noted. These are reproduced in tables IA and 2A. The pipes

.total internal free volume was 170 cm 3.

In Table 3 below, the layer formation results for certain of the examples and measurements of the porosity of the active material for certain of these examples are indicated.

Example 7 applies to the woven tube W. Examples 6, 9, 12, 15, 16, 19, 22 and 23 apply to the spun-woven tube SW, and the other examples apply to the non-woven tube NW. The pipes in all examples were filled in the manner described in example 1, i.e. that the solids are filtered out and the solids level gradually rises along the pipes, with the main quantity of the liquids being discharged from the pipes at the level which at the time in question was taken up by the solids.

Footnotes to Tables IA and IB and 2A and 2B and Table 3.

1) Ratio of solids to liquids. :

a) . The weight of solids removed with the samples of the filtrate has not been included as the weights of these samples were relatively small and there was no way to easily determine the ratio between solids and liquids in the filtrates. b) The ratios have been calculated without taking into account the amount of liquids that were removed with the paste in the tubes. These conditions yield

therefore a slightly too low content of solids in the slurries.

2) Ratio gray oxide/ red oxide.. These have been assumed to

remain constant, with the exception of when extra amount of gray

oxide or red oxide is added.

3) Wet pasta in a plate. The weight of the fabric pipe, the lead spines

and a bottom rail was 654 g. The values given apply to it

. wet filled plate plus a loose bottom rail minus 654.

4) % excretion from the sample. This is the height A of the solids in the container divided by the height B of the liquids from the bottom of the container, expressed as a percentage after the sample has been thoroughly shaken for 0.5 minutes and then allowed to settle in a vertical position for 24 hours.

The container is a test tube with a round bottom and an internal diameter of 1.5 cm, and at least 9 cm of slurry is filled into the test tube. 5) 1/2 lifetime of the suspension. This is the time that

takes the sample's solids level in the container described under 5) above to drop to halfway between B and A.

The examination is carried out by placing a rubber band with its lower edge at the level halfway from the bottom of the test tube, i.e. (B + A)/2 cm, vigorously shaking the test tube for at least 1/2 minute or until all solids have been displaced from the bottom of the test tube, and then setting up the test tube and measuring the time from this time to the time when. light is first visible under the rubber band.

6) Pump speed. This is simply a setting. The volume of the slurry pumped through the manifold was measured at different settings by collecting the slurry. as it emerged from the manifold. Two measurements were carried out for each pump setting. The volume of the slurry was measured.

A curve was then plotted of volume at pump settings 0, 20, 30 and 40 against time in seconds (using a stopwatch). An approximately straight line curve was obtained. 7) Time before the start of pressure increase. This is the time between the inlet valve measurement and when the pressure gauge actually starts to move instead of just fluttering. 8) Theoretical volume pumped before the start of pressure increase. This is the time given in column eight from the left of tables IA, 2A, 11A, 12A and 13A multiplied by the volume reading in column 7 from the left of tables IA, 2A, 11A, 12A and 13A and is. purely theoretical. 9) Layer formation. (Table 3) This is determined by pickling the plates in sulfuric acid with a specific gravity of 1.40 for 6 hours, followed by drying for 12 hours at 82°C.

The upper rail and the lower rail were then cut out of the plate and the remainder cut into four equal horizontal strips designated A, B, C and D, A being cut out at the end of the plate's lower rail. These were then weighed. The horizontal strips were •. then divided into four sections of three tubes omitting every fourth tube and designated 1 to 4, with a 1 at the cam side of the plate. The four sections 1 from each of the horizontal strips were then weighed, and the value given under 1 in table 6 is this value. The other vertical sections 2,

3 and 4 were weighed in the same way.

10) Pencil porosity. (Table 5) This is determined using

of the well-known mercury intrusion porosity measurement and is carried out for the same samples as in Table 3. Details regarding this measurement method are given in British Patent Document No. 1 331 257.

The viscosity values for certain of the slurries used in the above examples, as measured in the viscometer with a rotating blade, are reproduced in table 4 below.

The viscometer used is shown in fig. 6, 7 and 8.

The apparatus consists of a frame 110 which carries an electric motor 111 which drives a paddle device 120 via a gearbox 112

and a. torsion transducer 119. The speed in the gearbox 112 is registered by a tachogenerator 113 with an output which is fed to a digital voltmeter 113A. The voltage signal is emitted by the torsion transformer, and is transferred to a map printer 114. The printer has a variable map speed and a variable scale.

A sample container 130 is clamped onto a suitable table 115 which can be raised and lowered along guide rails 116 by means of a pneumatic cylinder 117. The sample container' 130 has a removable lid over the paddle assembly 120. The lid can be attached to the container using an external bayonet lock ( not shown).

The bucket arrangement 120 is removably attached to the output shaft 118 of the gearbox 112 and consists of a central rod 121 with a lower knob 122 which, during use, rests in a hole 132 in the container 130 bottom. The rod-121 has a diameter D5 of 1.3 cm and carries 3 pairs of blades 123, 124 and 125. The blades 123 and 125 are located in . same plane and has a right angle in relation to the vanes 124'. All vane blades are vertical and thus parallel to the rod's 121 axis. The vanes are carried on arms 126, 27 and 28. The distance D6 from the center of the arm 126 to the knob 122 is 6.5 cm, the distance D.7 from the center of the arm 127 to the knob 122 is .3.9 cm, and the distance from the center of arm 128 to knob 122 is 1.6 cm. The width of each vane D3 is 1.2 cm, and a column D2 is 1.2 cm and its thickness 0.1 cm. The distance D4 from the inner edge of each vane to the surface of the stand 121 is 1.5 cm.

The distance Dl between the outer edges of the vanes i

a pair of blades is 6.8 cm.

The inside height of the container 130 is 8.2 cm and its inside diameter is 8.8 cm. There are four internal screens 135 arranged at the ends of diameters at right angles to each other. The thickness D10 of h<y>er blade 135 is 0.3, and it extends a distance inside D9 of 0.5 cm. The distance Dll. between the vanes along a diameter is 7.6 5 cm. Each vane extends the full height of the container.

The container and paddles are made of smooth stainless steel.

The device is used as follows:

The container is filled to a depth of 8.2 cm with the material to be examined, and raised to a position where it is clamped to the table 115, and the lid 131 is attached.

The chart recorder 114 is started, and the motor 111 is then started with the gear set to a low shear speed, e.g. 6 up. The initial torsion and the steady state torsion are sensed by the torsion transducer 119. and the motor and printer are kept running until a constant torque value has been recorded for at least 2 minutes. This is the torque value under steady state. The torsion value under steady state is noted, and if an original peak was present, this fact is noted.- The sample is then removed and shaken with the rest of the material to be measured, and the container is refilled. The measurement is then repeated at a higher shear rate, e.g. 18 p.m. The cycle is repeated for as many cutting speeds as desired.

The background torsion value, i.e. med. container 130 empty, was found to be 0.055 kg-cm at all shear rates listed in Table 2. The same value was obtained when the meter was filled with water.

The torsion value, as defined herein, measured by the rotating blade viscometer, is the value of the steady-state torsion value of the sample measured in the above-described manner with the above-described machine at a shear rate of 6 revolutions of the vanes per minute at an ambient temperature of

20° C, minus the background value at 20° C. ' .

According to the invention, it has been shown that with a ratio between oxides and water of more than 2.5:1, the filtration process does not occur, and the process is far more difficult to control. Thus there is a tendency for the plates to become overfilled and too dense and for the tubes to be filled unevenly, and large pockets and gaps are apt to occur and also areas of lower specific gravity distributed unevenly through the plate.

With a ratio between oxides and water of less than 0.4:1, the time it takes to fill the plate becomes very long, and the oxide weight that can be introduced into the tubes tends to fall to unacceptably low values.

It is thus preferred that the weight of the wet paste in the plates used in examples 2-27 is at least 800 g, preferably 800 - 950 g.

It appears from table 4 that the viscosity of the aqueous slurries used according to the invention is very low and essentially the same as for water compared to the viscosity of ordinary accumulator pastes and the paste according to example 1 in German specification no. 2 243 377. Compared to a torsion value determined by a viscometer with a rotating blade of 48.3 kg-cm according to the German specification thus typical pourable self-levelling slurries used according to the invention have values below... 0.138 kg-cm, and more specifically not above 1.104 kg-cm Examples' 28 - 33

These are examples of high viscosity mixtures and are given for comparison purposes only and are not exhaustive of the present invention.

These are examples of the use of mixtures having a torsion value (as defined herein) determined with a rotating blade viscometer of 0.083 kg-cm and above. Examples 2-8 - 32 were carried out with that in fig. 1-5 shown apparatus. Example 33

was carried out by that in fig. 10 - 19 showed apparatus. This appliance is different from the previous one, appliance only with it off

quantity of slurry delivered by the monopump, when using a pre-set pressure-sensitive switch that automatically shuts off the supply of slurry as soon as the pressure in the supply pipes to

the manifold reaches a predetermined value, and with certain design features..

The relative quantities of components and the conditions used in the examples are reproduced in the tables 6A and 6B below.

The viscosities for the mixtures used are given in

table 7 and the stratification results for example 33 in table 8.

None of these mixtures gave fill by the filter-fill method. They all gave a fill from the inlet end downwards. Some mixtures, such as the mixture according to Example 30, were even too thick to be pumped into the pipes. In example 31, not all pipes were properly filled. It appears from table 8 that the specific gravity of the active material in the plate according to example 33 varied considerably, i.e. by + 20%, compared to the highest variation according to table 3 of + 4%.

It was also found that the use of these higher viscosity pastes was prone to introduce problems due to occasional blocking of the machinery during use.

It has been mentioned above that other electrochemically active materials besides lead/acid active materials can be used for carrying out the present method.

The components used in such alternative embodiments must of course be compatible with each other. When, for example, alkaline, negative, active materials are to be used, the spines must be made of a metal with sufficient corrosion resistance to the alkaline environment, and e.g. current collection spines of round steel or strip steel can be used and these can be nickel-plated, and the polyester fabric tubes can be replaced with polyamide fabric tubes, e.g. of nylon. Preferred examples of alkaline electrochemically active materials include nickel hydroxide for the positive plate and cadmium hydroxide for the negative plate. These typically contain a relative amount of an electrically conductive material, e.g. graphite, which is sufficient to ensure a satisfactory conductivity, preferably 5-15% by weight of graphite. Steel can be used as the current collection element,

<p>g it can also be used as an enclosure for the active material in a suitable porous state so that filtration can be achieved. Other alkaline, electrochemically active materials include iron oxide as the negative, active material.

The nickel hydroxide may also contain distributed nickel particles or flakes to improve its electrical conductivity. The iron oxide may also contain a conductive material to improve the conductivity of the iron oxide.

The electrolyte typically consists of aqueous potassium hydroxide which

may contain a small amount of lithium hydroxide.

A number of different electrochemically active lead/acid materials have already been discussed, including gray lead oxide and red lead oxide. Gray lead oxide is sold in a number of different qualities with different contents of lead and lead monoxide (PbO) and different particle sizes, depending on the method of production. Hardinge oxide, which is produced by grinding lead blanks in a ball mill, has a lead content of 20-40% by weight, e.g. 30% by weight, and a PbO content of 80-60% by weight, e.g. 70% by weight.

It is sorted using air, and the coarser particles are returned for renewed grinding. It has an average particle size of 15-25 µm, preferably 20 µm.

Tudor oxide is another oxide produced by grinding down, but it is not sorted by air and has an average particle size of 30-50 / o^ m, preferably .4 0yum.

Oxide produced by the roasting process (eg the Barton boiler process) has an average particle size of 12-15JUA<\.

Although the invention has made it possible to use chemically inert casings, this does not exclude that the tubes can be filled with the active materials in a metallic state which can be chemically or electrolytically converted into electrochemically active form in the casing, and the invention therefore also includes such execution form. The term "mixture for active material" thus includes materials that can be converted into electrochemically active form in the porous casing before or after installation in the cell.

A number of other electrochemically active pairs exist which have been proposed for use in electric batteries.

The method has so far been described with reference to secondary or rechargeable systems. However, it can equally well be used for primary battery systems in which the active materials or one of these can be enveloped by a porous envelope and can be introduced into the envelope as a suspension in a liquid, preferably aqueous, slurry.

The liquid used as a suspending agent in the slurry. is most simply aqueous, and this is clearly preferred due to costs, safety and inertness. If, however, an aqueous carrier should cause problems, it can be replaced with other liquid carriers that are suitable for the active material used.

Examples of other battery systems for which the present method is applicable are indicated in the table 9 below.

The active materials specified below will be used in the form of particles of a suitable size to achieve filtration filling together with the porous casing used.

Experiments have shown that non-woven tube sheets can be filled with the help of

of the filter filling process using a positive alkaline active material or a negative alkaline active material.

It has thus been shown according to the invention that an ordinary negative, alkaline, active material (containing 76% by weight cadmium hydroxide, 5% by weight metallic cadmium, 15% by weight iron oxide, 2% by weight graphite and 2% by weight paraffin) can be introduced only under the influence of the weight in the same nonwoven, NW, tubesheets used in Examples 2-27. According to the invention, it has been shown that a ratio between active material and water of 0.75:1-0.2:1 produces slurries that are filled from the lower end of the pipes up to the inlet with a good, even distribution of active material in the pipes. The solids in

these slurries separate relatively quickly in a similar way to the lead/acid slurries described above and are all easily pourable liquids.

Similarly, a common positive alkaline active material (containing 85% by weight nickel hydroxide and 15% graphite in the form of a mixture of powdered graphite and graphite flakes) when used in the same solids-to-liquids ratio will give slurries that are filled from the tubes lower ends up to the inlet with a good, even distribution of the active material in the pipes.

The solids in these slurries are also separated relatively quickly in a similar way to the lead/acid slurries described above, and these slurries are all easily pourable liquids.

Experiments with the application of pressure against the slurry have shown

that the amount of active material introduced into the pipes can be increased by applying pressure in a similar way as shown above in connection with active materials of lead/acid.

Another factor that must be taken into account if a satisfactory filtration fill is to be achieved is the relationship between the particle sizes in the slurry and the permeability, structure and pore dimensions, i.e. filtering capacity, of the material from which the porous casing is made. Thus, with a highly porous wrap, such as the woven wrap described in connection with Examples 2-27, especially Example 7, the mixture of gray Hardinge oxide and; red lead oxide in a ratio of 33:67 and with a relatively low particle size and a ratio of solids to liquids of only 1.35:1, as used in Example 7, not filling the woven plate as the layer of active material was not built up inside in the pipes.

However, when 100% gray Tudor oxide with an average particle size of 40yitm and at a solids to liquids ratio of 2.5:1-2.0:1 is used, these woven tubes, W,

filtration is satisfactorily filled. These tubes can too. is filled satisfactorily-using the ratios between solids and liquids for slurries where the ratios between the Tudor oxide and red lead oxide are 80:20, 60:40, 40:60 and 20:80.

These tubes can also be filled with Hardinge oxide and with mixtures of Hardinge oxide and red lead oxide in a ratio of 80:20 and at these ratios between solids and liquids.

The invention has so far been described with reference to active materials of non-acidified lead/acid. However, active lead/acid materials can also be used after acid has been added to the materials to at least partially sulphate them.

According to the invention, it has been shown that the addition of acid has a clear effect on the viscosity of the slurry for certain degrees of sulfate concentration.

The reason for this effect is not completely known, and although the invention is not dependent on a particular theory, it is assumed that this may be due to variations in the degree of hydration and thus intramolecular or intraparticle interactions with variation in the amount of sulphate intermediates. which are present in the acidified slurries. The figures for torsion values obtained by measurement with a viscometer with rotating blades and indicated in the table 10 below clearly show this variation in viscosity with variation in the degree of sulphation.

It must therefore be ensured that a system is used in which the ratio between solids and liquids is kept sufficiently low, so that the percentage sulphation used will not cause the slurry not to provide filtration filling when it is used

together with the particular covering cloth in question.

It has been found according to the invention that, at least when using the above-described nonwoven fabric, NW, along with a wide range of lead/acid slurries, slurries appear to have a torsion value (as defined herein) determined by a rotary blade viscometer of less than 0.083 kg-cm at 20°C will fill by filtration filling, while slurries with such a torsion value of 0.083 kg-cm and above will fill by injection filling. Although the invention is thus not limited to the use of slurries with torsion values below 0.083 kg-cm, the use of such slurries is strongly preferred.

Below are given certain non-complaining examples of acidified slurries which provide filter fill in the examples 34-42 below.

g of lead oxide requires 0.4 ml of sulfuric acid with a specific gravity of

1.4 to achieve 100% sulphation.

For gray lead oxide containing 30% lead and 70% lead oxide, the sulphation degree Y can be expressed using the following equation:

Y 216.4 X the volume of 1.4 specific gravity H^ SO^ in liters

weight of gray lead oxide in kilograms

Examples, 34-42

These examples were carried out using the apparatus described with reference to Figs. 1-5.

The relative amounts and the conditions used and the results obtained are reproduced in the following tables 11A and 11B. For all these examples, 100% Hardinge was used. oxyd, ratio between solids and liquids of 1.28:1-0.43:1 and non-woven pipes.

It appears that with these acidified slurries somewhat lower values were obtained for the wet paste in the plate, compared to the non-acidified slurries according to examples 1-27. However, it appears from the table 14 below that the active material in the tubes only has a lower specific gravity and that it has a good distribution and no harmful layer formation.

The viscosity of the slurries used in examples 34 and 38 is reproduced in table 15.

Examples 43-50

These examples were carried out using the apparatus described with reference to Figs. 1-5.

The relative quantities and conditions used and the results obtained according to the examples are reproduced in the following tables 12A and 12B. In these examples, high relative amounts of red lead oxide were used, a ratio between solids and liquids of approx. 1.6:1 and non-woven tubes, NW.

The layer formation results are reproduced in table 14.

The viscosities for those used in Examples 44, 47, 48 and 50

slurries are given in table 15.

The degree of sulfation shown in Table 12A was obtained simply by substituting the weight of gray lead oxide for the weight of red lead oxide. The slurries according to examples 47-50 were made by adding gray lead oxide to the slurry according to example 46.

Examples 51-56

These examples were carried out using the apparatus described with reference to Figs. 10-19.

The relative quantities and conditions used and the results obtained in these examples are reproduced in the following tables 13A and 13B. In these examples, high relative amounts of gray lead oxide and higher degrees of sulphation than in examples 34-42, and non-woven pipes were used. o

Layering results are given in Table 14, and the viscosities for the slurries used in Examples 51, 54, 55 and 56 are given in Table 15.

Footnote: Regarding the viscosity values, see the general information before the examples.

A comparison of the layer formation results according to table 8 and according to table 14 makes it clear that plates which are filled by filtration (table 14) have significantly less layer formation than plates which are filled by injection (table 8) ..

Footnotes, to take bells 11A and 11B- 13A and 13B

!)■'% suifating. It was assumed that all acid is absorbed by and reacts with the excess of oxide at the stage when it is first added, and thus that the % suifation remains constant until more acid is added, i.e. a proportion of the acid is removed with each paste sample that is removed .

2) Ratio of solids/liquids.

These are calculated to include the entire amount of any

acid that is added.as a liquid.

The effect of a presulphation of the active lead/acid material has been described with reference to three parts of the possible theoretical range for the composition of the slurries. These are 100% gray lead oxide with a solids/liquids ratio of 1.3:1-0.4:1

and sulfation degrees of 1.5-4.0% (Examples 34-42). Ratio between gray lead oxide and red lead oxide of 0:100-20:80 with solids/liquids ratios of 1.5:1-1.7:1 and sulphation degrees of 0.05-0.8% (examples 43-50). Gray lead oxide:red lead oxide ratio of 100:0-55:45 with solids/liquids ratios of 0.4:1-0.8:1 and sulphation rates of 1.0-17% (Examples 51-56).

It is believed that there are several other presulfated lead/acid active material compositions that will provide an effective filter fill, and one skilled in the art will, based on the teachings provided herein, regarding the effect of acid on viscosity and the effect of varying the ratio of solids to liquids, and the effect of acid on the viscosity, and the effect of a variation in the ratio of gray lead oxide to red lead oxide, and the effect of a variation in the permeability of the porous casing, could easily select a suitable composition and a suitable material for the porous casing.

Claims (54)

1. Procedure for the production of coated plates for electric batteries, - where a mixture for an active material containing liquids is introduced into the plate's porous coating when the coating has been arranged on the plate's current-conducting element, characterized by using a mixture for active material with such liquid content that active material is filtered out of the porous casing and a layer of active material is built up in the casing, the layer being built up from the end furthest away from the end where the mixture is introduced, and back to the end where the mixture is introduced, and liquid emitted through the enclosure walls while the layer is being built up. 2. Method according to claim 1 when filling coated plates for electric batteries-, where a mixture for active material is introduced into the plate's porous coating when the coating is arranged on the plate's current-conducting element, characterized 'by that the mixture for the active material is introduced into the casing in the form of an aqueous slurry, while the casing is essentially vertically arranged so that solid substances can be deposited on the bottom of the casing under the influence of gravity, using an aqueous slurry containing a weight ratio of active material and water of 0.4:.1-2.5:1 and a material is used for the casing - which is able to filter out active material, but like. allows liquids to pass so that the solids are at least partially retained in the casing and the liquids at least partially pass out through the walls of the casing, and as the introduction of the slurry into the casing is continued until the casing has been filled with active material, after which the pressure in the supply until the envelope is allowed to rise to above 0.35 kg/cm <2> , but not to above 7.03 kg/cm 2 , and then canceled. 3. Method according to claim 1, characterized in that a number of pipes arranged next to each other and with a current-conducting element placed in each pipe are used as casing. 4. Method according to claim 3, characterized in that the slurry is introduced into the tubes with such a volume that the ratio between the volume of the slurry and the total internal free volume for the tubes in the plate is at least 2:1. 5. Method according to claim 4, characterized in that the ratio is 3:1-15:1. 6. Method according to claims 1-5, characterized in that an aqueous slurry comprising an aqueous mixture of particulate, active material and liquids is used, the weight ratio between the solids and liquids being 1:1-1.8:1. 7. Method according to claims 1-6, characterized in that a slurry with a specific gravity of less than 2.5g/3 cm is used 8. Method according to claims 1-7, characterized in that a slurry is used with a torsion value (as defined herein) determined with a viscometer with a rotating blade of less than 0.083 kg-cm at 20°C. 9. Method according to claims 1-8, characterized in that the back pressure in the supply of slurry to the enclosure is allowed to rise to a pressure of 0.35-3.52 kg/cm 2 after the enclosure has been filled. 10. Method according to claim 9, characterized by . that the pressure is allowed to increase iyl^lO of the time it takes to fill the enclosure,' up to a time corresponding to that which it takes to fill the enclosure. . 11. Method according to claim 10, characterized in that the envelope is filled within 5-15 s and that the pressure is allowed to • increase for 1-15 s. 12. Method according to claims 1-11. characterized . in that a material with a nitrogen permeability of 0.5-20 l/cm 2 per minute. 13. Method according to claim 10, characterized in that a material with a permeability for nitrogen of 3-10 l/cm 2 per minute. 14. Method according to claim 13, characterized in that material in the form of a non-woven sheet of polyester fibers is used for the wrapping • which is 0.5-0.7 mm thick and weighs 120-160 g/cm 2 and has a permeability for nitrogen of 8.0 1/ 2 2 cm per minute and a permeability for. water of 1.5 l/cm per minute. 15. Process according to claim 14, characterized in that a non-acidified slurry mixture is used which contains gray lead oxide and red lead oxide in a weight ratio of 66:34 - 33:67 and with a weight ratio between solids and liquids of 2.0:1 -0.5:1. 16. Method according to claim 15, characterized in that the weight ratio between solids and liquids is 1.5:1 - 0.7:1. 17. Method according to claim 12, characterized in that a material of single-spin woven cloth with 15-25 weft threads per cm and 15-25 warp threads per cm and with a nitrogen permeability of 5 l/cm 2 per minute. 18. Method according to claim 17, characterized in that a non-acidified slurry mixture is used which contains gray lead oxide and red lead oxide in the weight ratio 66:34-33:67 and with a weight ratio between solids and liquids of 2.5:1-0, 9:1. 19. Method according to claims 1-14, characterized in that an active lead/acid material is used as active material which is at least partially sulfated before it is introduced into the porous casing of the plates. 20. Method according to claim 19, characterized in that an active material with a sulphation degree of less than 17% by weight is used. 21. Method according to claim 20, characterized in that an active material with a sulphation degree of 0.05-16.7% is used. 22. Method according to claim 19, characterized in that an active material is used which consists of gray lead oxide and which has a degree of sulphation of up to 4% and a weight ratio between solids and liquids of 1.3:1 - 0.4:1. 23. Method according to claim 19, characterized in that the active material used is gray lead oxide containing up to 45% by weight of red lead oxide and which has a sulphation degree of 10-17% and a weight ratio between solids and liquids of less than 0.8 :1. 24. Method according to claim 19, characterized in that the active material used is red lead oxide containing up to 20% by weight of gray lead oxide and which has a sulphation degree of up to 0.8% and a weight ratio between solids and liquids of no more than 1 ,7:1. 25. Method according to claim 1-18, characterized in that an active material with an average particle size of 1-100 o^ m is used. 26. Method according to claim 25, characterized in that an active material with an average particle size of 5-20 µm is used. 27. Method according to claims 2-26, characterized in that the casing is clamped firmly at the top and bottom while the slurry is introduced into the pipes, so that liquids can escape from the entire area of the casing. 2-8. Method according to claim 2-27, characterized in that a supply of the slurry mixture is continuously mixed during the filling and that a smaller proportional proportion of the slurry supply is introduced into each casing plate from this ■continuously mixed supply. 29. Method according to claim 28, characterized • in that the weight ratio between the active material in the continuously mixed slurry supply and the individual filling weight is 1300:1 - 25:1. 30. Method according to claims 2-29, characterized in that the supply of the slurry mixture is delivered by a pump to a filling manifold for supply to a plate, from an agitated supply of slurry in a storage tank, using a pump which provides a uniform delivery and keeps the slurry suspended, and the slurry in the intervals between introduction into a shrouded plate via the filling manifold is recirculated from the pump's outlet via a recirculation pipe which is connected to the pump's outlet, to the storage tank and from there via a supply pipe to the pump's inlet. 31. Apparatus for carrying out the method according to claims 1-30 when filling sheathed batteries in plates, characterized in that it comprises at least one filling station which comprises a device for supporting a plate's sheath arranged on its current-conducting element in an essentially vertical plane . the storage tank of the manifold for a selected filling station. 32. Apparatus according to claim 31, characterized in that the delivery device comprises a recycling device for recycling the slurry to the storage tank when the slurry is not delivered to a filling station. 33.. Apparatus according to claim 31 or 32, characterized in that the delivery device to the manifold comprises a pump with an inlet line which. is in connection with the storage tank, and a valve device, i.e. the recirculation valve, which is connected to the pump outlet for directing the slurry from the pump outlet to a filling station or for recycling of the slurry to the storage tank. 34. Apparatus according to claims 31-33, characterized in that the support device for the plate is designed to support pipe plates and comprises a frame which is rigidly attached to the filling manifold and carries upper and lower clamps for releasably clamping the plate to the frame. 35. Apparatus according to claim 34, characterized by . that the clamps are provided with teeth and adapted to the outer surface profile of the bottom and top of the tube sheet. 36. Apparatus according to claim 34 or 35, characterized in that at least the upper clamp is provided with a flexible sealing liner. 37. Apparatus according to claims 31-36, characterized in that it is arranged for use in connection with tube sheets and where the manifold has an outlet nozzle device consisting of rigid supply tubes arranged at a distance from each other along a straight line at their centers on the centers of the sheet tubes and with external diameters that correspond to the internal diameters of the sheet metal pipes. 38. Apparatus according to claim 37, characterized in that the supply pipes 'extend through a pliable seal, the dimensions of the frame in relation to the plate being such that the end of the plate must be forced up into the seal to place the plate in the support device. 39. Apparatus according to claims 33-38, characterized in that a pressure-sensitive valve is arranged in connection with each filling manifold's inlet side. 40. Apparatus according to claims 33-39, characterized in that at least two filling stations are arranged for each pump and slurry storage tank and that the circulation valve is a three-way valve. 41. Apparatus according to claims 33-39, characterized in that at least two filling stations are arranged for each pump and slurry storage tank and that the manifolds are supplied with slurry from a common supply line which is connected to the pump's outlet and the recycling line, and that a valve device is arranged to selectively connect each manifold to the supply the cord. 42. Apparatus according to claims 39-41, characterized in that the pressure-sensitive valve is a pressure reduction valve. 43. Apparatus according to claims 39-41, characterized in that the pressure-sensitive valve or each pressure-sensitive valve is arranged for initiating an automatic setting of the recirculation valve or of the valve arrangement which connects the manifold or each manifold with the common supply line, in recirculation position. canceling the pressure in the supply line to the plate as soon as a predetermined pressure has been reached. 44. Apparatus according to claims 31-43, characterized in that the pump comprises a rotor in the form of a single-start spiral spring armature in a cylinder in the form of a double-start spiral spring with twice the pitch of the rotor, and where the rotor rotates around its axis in one direction while its axis revolves around the axis of the cylinder in the opposite direction and at the same speed. 45. Apparatus according to claims 34-44, characterized in that the upper clamp has a fixed toothed surface and a movable cooperating toothed surface which can be removed from the fixed surface while it is held parallel to it, by means of a pneumatic or hydraulic device. 46. Apparatus according to claims 34-44, characterized by . that at least one of the opposite surfaces of the lower edge of the upper clamp or the upper edge of the lower clamp is chamfered. 47. Apparatus according to claims 34-46, characterized in that the rear surface of the upper clamp carries a grooved part to facilitate the placement of a plate in the clamp. 48. Apparatus according to claims 34-47, characterized in that the lower clamp has a front clamping surface to which the hinge is connected and is located lower than a rear clamping surface, and in that biasing devices are arranged to move the front plate to the closed position or for a completely open position. 49. Plant for filling sheathed battery plates, characterized in that it comprises a central station for preparation of slurry and at least one filling apparatus according to claims 31-48 and a device for supplying slurry from the central station to the filling apparatus. 50. Plant according to claim 49, characterized in that the device for supplying slurry comprises a device for continuous supply of slurry to the filling device or each filling device and a return device for returning slurry to the central station, whereby the slurry can be continuously 'circulated' . 51. Plant according to claim 49 or 50, characterized in that the slurry preparation station comprises a tank, a weighing device for weighing the tank, a stirring device for keeping the slurry suspended, a device for supplying active material and a device for supplying of liquid. 52. Plant according to claim 51, characterized in that the weighing device comprises a load cell arranged below the tank. 53. Plant according to claim 51 or 52, characterized in that the stirring device comprises a stirring arm which is arranged for rotation near the bottom of the tank. 54. Procedure when using the facility according to claim 49-. 53/characterized by the fact that slurry is continuously supplied from the central preparation tank to each filling device and back to the central tank at such a speed that the contents of the filling device's slurry tank are replaced at least every hour.