Lindenberg, Hans-georg (Hannover-Stocken, DT)
Prause, Siegfried (Berenbostel, DT)

05/140531

07/10/1973

05/05/1971

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Varta Aktiengesellschaft (Frankfurt am Main, DT)

29/38R

29/650, 29/564.100, 29/730, 29/718, 29/38B

H01M2/28; H01M10/14; H01M2/26; H01M10/06; H01M35/18; B23P19/04

29/24D,24R,23R,28F

Eager, Thomas H.

We claim

1. A machine for producing electrode-plate subassemblies including electrode-plates, cell connectors, pole bridges, separators and connector lugs for electric storage batteries, comprising a turntable stepwise rotatable about a vertical axis, peripherally distributed axles mounted on said table and protruding radially therefrom, respective cassettes mounted on the outward ends of respective ones of said axles and having the shape of bilaterally open block boxes with cell partitions, said cell partitions including slots for insertion of loose plate subassemblies into said slots, work stations arranged around said table and correlated to said respective cassettes, one of said respective stations having means for aligning said electrode-plate connector lugs, a second one of said stations having means for treating the lugs with a fluxing medium, a third one of said stations having a casting device for joining said cell connectors and pole bridges with the lugs of equipolar electrode-plates of the subassembly, said device having a casting mold for liquid lead, and a work station with a press device for pressing the interconnected plate subassemblies through the cassette into battery boxes arranged beneath the cassette, said battery boxes being provided with cell partitions with recesses, said work station being located after said third station.

2. A machine according to claim 1, comprising an injection molding device and conveying means connecting said injection molding device with said press device, said injection molding device having injection molds comprising two half shells adapted to be pressed against the cell partitions of the battery box, said half shells being shaped to also form undercuts at the sides and top of the cell connectors; a distributor tool device for injecting plastic into said molds to encase the cell connectors while filling the recesses in the cell partitions and forming a protruding member at the top edge of the cell partitions.

3. A machine according to claim 1 comprising a vertical column about which said turntable rotates, a bridge rigidly connected to said column, one end of said bridge being provided with gear segments, one end of said axles having spur gears, said turntable being lifted by said spur gears engaging with said gear segments, said gear segments rotating the cassettes by 180° about the axis of respective axles during the rotation of the turntable before reaching said second station and by an additional 180° before reaching said work station with a press device.

4. A machine according to claim 3, wherein said cassettes comprise mounting devices including mounting fingers projecting into said slots in said cell partition walls.

5. A machine according to claim 4 wherein said press device is provided with claws located above the cassettes, said claws being downwardly movable to communicate with said cell connectors for clamping said cell connectors and said pole bridges for pressing the plate subassemblies through said cassette and into said battery box, said battery box being located below the cassette, said plate subassemblies being pressed through the cassette after the mounting device is released and retracted.

6. A machine according to claim 1 wherein said means for aligning is provided with gauges movable to communicate with said cassettes and to enclose the plage lugs, and a vibrating apparatus.

7. A machine according to claim 6, comprising at least one additional station including means for cleaning the plate lugs, said cleaning means comprising at least one brushing roller for brushing the plate lugs, said additional station being positioned after said station having means for aligning said connector lugs.

8. A machine according to claim 1, comprising an additional station including means for pre-heating the plate lugs and said fluxing medium, said additional station being located after said second station.

9. A machine according to claim 1 wherein said casting mold is shaped to form through strips with uniform cross-section to simultaneously produce said cell connectors and said pole bridges, said mold being heated by means of a resistor coil, said casting device including containers for storing liquid lead located on opposite sides of said casting mold, said containers being movable to be positioned above the casting mold and being provided with valves for filling a predetermined amount of said liquid lead into the molds, and blades for insertion into the casting mold to produce an undercut portion at the lower portion of the cell connectors.

10. A machine according to claim 9, wherein the casting mold is provided with means for gauging the length of the mold and controlling the heating thereof in response thereto.

Our invention relates to an automatic machine for manufacturing plate subassemblies for electric storage batteries and, more particularly, for manufacturing electric storage batteries having a plurality of mutually interconnected cells.

A similar machine is disclosed in the German Published Patent Application 1,162,432. Such a machine, however, is disadvantageous in that only single plate subassemblies can be provided with the cell connectors therein, and the plate subassemblies have to be subsequently manually inserted in plural cell battery boxes and then be interconnected by means of connectors or by welding two adjacent cell connectors to each other.

There is already known a method of production of an electric storage battery having cell connectors passing through the cell partition walls, where the plate subassemblies provided with a system of intercell connectors are pressed into a battery box, made of, for example, polypropylene, and where the partition walls are provided with recesses for accommodating the intercell connector systems. The connectors pass through the partition walls approximately at the elevation of the pole bridges and are provided in the region of the recesses in the partition walls with protrusions, which are each provided with a circumferential groove for accommodating the cell partition wall. The part of the groove which rests upon the cell partition wall is provided in the protrusion in the intercell connector system, and, further, is provided with an undercut portion. Subsequently, an injection mold, which conforms to the partition wall, is attached to at least one intercell connector system and compressed plastic material is injected into the mold, which fills the spaces between the partition wall recess and the connector, as well as the recess of the partition wall of the battery box which is made of plastic. It is advantageous to provide a protrusion in the cell partition wall in the region of the recess, and to provide the protrusion with a circular slot. Preferably, the protrusion is provided, at least partially, along the upper edges of the partition walls simultaneously with the filling of the recesses.

This protrusion simplifies the attachment of the battery lid to the battery box, both of them being made of plastic and, in general, the so-called reflective welding process is used to accomplish the same. In this process, the boundary layers of all box walls are heated by means of a heating apparatus shaped so as to conform to their shape, and the corresponding regions of the lower surface of the battery lid are also heated by a respective heating device, both of them such that the material of the surface portions to be connected is plasticized. In this manner, the parts which are assembled and pressed together after the heating equipment is removed are firmly and tight-fittingly welded together. (German Published Applications 18, 04, 800; 19, 07, 411; and 19, 28, 288.)

It is an object of our present invention to provide an automatic machine for the manufacturing of complete plate subassemblies for an electric storage battery of the above-described kind, wherein the plate subassemblies are provided with cell connectors and are mutually interconnected.

Another object of our invention is to provide a machine for manufacturing complete plate assemblies automatically for plural cell storage batteries.

Still another object of our invention is to provide such an automatic machine which is relatively fast in operation.

Yet another object of our invention is to provide such an automatic machine which securely joins and connects the members of the plate subassembly for easy insertion into a battery box or housing.

Other objects, advantages and features of this invention will become more apparent hereinafter.

In accordance with the invention, these objects are accomplished by providing a stepwise rotating turntable, wherein a plurality of equally spaced cassettes are arranged around the circumference thereof. The cassettes are arranged at the ends of axles supported in journals and have the form of bilaterally open containers with through slots in the cell partition walls in which loose plate subassemblies can be inserted. Work stations are located about the turntable whose number corresponds to the number of the cassettes and which consist of an apparatus for aligning the plate lugs of the electrode plates, apparatus for treating the plate lugs with a fluid, and an apparatus for casting-on all cell connectors and pole bridges on the plate subassemblies, and, finally, a working station for pressing the mutually interconnected plate subassemblies through the cassette and into the battery boxes arranged underneath the cassette.

The invention will be further described with reference to embodiments thereof, illustrated by way of example on the accompanying drawings in which:

FIG. 1 is a diagrammatic representation of the machine according to our invention;

FIG. 2 is a perspective view of a set of mutually interconnected plate blocks with the intercell connectors, as manufactured in our machine;

FIGS. 3.1 to 3.3 show in a greater detail an intercell connector as manufactured by our machine, FIG. 3.1 being a perspective view, FIG. 3.2 a cross-sectional view, and FIG. 3.3 a perspective view of a mold to be used for injection molding of plastic material around the intercell connector;

FIG. 4 is a front view of the turntable of the machine;

FIGS. 5.1 to 5.3 show the cassettes attached to the turntable, with FIG. 5.1 being a top plan view, FIG. 5.2 a partial cross-sectional view, and FIG. 5.3 a perspective view of the cassette;

FIGS. 6.1 and 6.2 show the various work stations located around the turntable in a diagrammatic view;

FIG. 7.1 is a cross-sectional view of the casting apparatus;

FIG. 7.2 is a top view of the casting apparatus;

FIG. 8 is a sectional view of a claw which is used for pushing the plate subassemblies through the cassette;

FIG. 8a is a cross-sectional view of FIG. 8 taken along the line 8a-8a;

FIG. 9 shows a schematic cross-section of the injection molding machine; and

FIG. 10 is an illustrative schematic diagram of electrical circuitry for automatically stepping the turntable through its plurality of working positions.

The assembly according to FIG. 1 comprises a set stacking machine 1, in which the plate subassemblies, (FIG. 2) consisting of electrode plates 12 and separators 13, are stacked. The plate subassemblies are transferred by means of a conveyor belt 1a to a stepwise rotatable turntable 2, and are inserted in cassettes 3 (to be explained below) and to which are attached, in various working steps, pole bridges and cell connectors. The direction of rotation of the turntable is illustrated by arrow 4.

At the last work station X of the turntable, a completed plate subassembly is provided ready to be inserted in the battery boxes, as they are shown in FIG. 2 with the assembled battery including pole bridges 14.1, cell connectors 14, and a slot 15 in the pole bridge connecting system, the pole bridge connecting system projecting above the cell partition wall.

The interconnected plate subassemblies are pressed in the battery housing in work station X the battery housing being provided with suitable recesses in the cell partition walls thereof for receiving the groove 15 (FIG. 2) of the cell connector 14. From there, the battery box, with the inserted plate subassemblies, is transferred to an injection molding machine 9, where the cell connector is encased in a plastic material 16 (FIGS. 3.1 to 3.3). Simultaneously, the recess in the cell partition wall is filled with a plastic material and a protruding member 18 is found along the upper edge of the coil cell partition walls (see FIGS. 3.1 and 3.2).

From the injection molding machine 9, the conveyor belt 1a carries the battery boxes to a welding apparatus 8, in which the top covers are welded to the battery boxes by a welding process, such as mirror welding. After that step, terminal poles are welded to the pole bridges for easy connection to an electrical system, for instance, of a car.

An important part of our invention is the turntable 2, which is shown in FIG. 4 in cross-section, which rotates about a vertical column 21. The turntable 2 is provided with a stepping drive (not shown), by which the turntable is stepwise driven. The control of the rotating movement is exercised by conventional limit switches, which are provided on the turntable in the region of work stations I to X. During the movement of the turntable by one step, a lifting movement always occurs, caused by a lifting drive 22. The lift is obtained by conventional cam assembly (not shown) provided on the column 21.

A bearing assembly 24 is arranged on the turntable 2 (FIG. 4), and axles 23 are journaled therein with cassette 3 being attached to the end of each axle. These axles 23 are provided with spur gear 25 at their other ends. In the lifted position of the turntable 2, the spur gears 25 mesh with gear segments 26, which are rigidly connected to column 21 via a bridge 27 and do not move with the turntable 2. During the rotation of the turntable 2, a rotation of the cassettes 3 by 180° is accomplished by means of the gear segments 26, the position at which the rotation occurs being predetermined by the position of the bridges 27 carrying the gear segments 26. For positional adjustment of the cassettes 3, there is provided a manually operated adjusting device 28 on each of the axles 23.

There are provided ten axles 23 of the above type on the turntable 2, each of them being provided with a cassette 3 as shown in FIG. 1. Accordingly, the turntable 2 is provided with various work stations I to X. In work stations I and II, there is accomplished the insertion of the plate subassembles; in III, the alignment of the plate lugs 11; in IV, a test of completeness; in V and VI, a cleaning of plate lugs; in VII, treatment of the subassembly by a fluxing medium; in VIII, a pre-heating; in IX, the welding operation; and in X, the pressing of the completed plate subassemblies into the battery box or housing. Accordingly, work benches 100 to 800 (FIGS. 6.1 and 6.2) are arranged about the turntable 2, in which position the cassettes 3 rest during the interval between the successive rotational movements of the turntable 2.

The cassette 3 is shown in FIGS. 5.1, 5.2 and 5.3. These cassettes serve to receive the plate subassemblies manufactured in the set stacking machine 1, which subassemblies consist of the conventional positive electrode plates, negative electrode plates and separators, which are manually inserted into the cassettes 3. The shape of these cassettes 3 conforms to the usual shape of an automobile storage battery. Correspondingly, the cassettes are provided with a frame 31 and cell partition walls 32, which are provided with slots 33 at the positions where the cell connectors 14 pass through the partition wall. The insertion of the loose plate subassemblies is accomplished at the work stations I and II, and a work bench 100 is provided at each of these positions.

Referring to FIG. 6.1, the cassettes 3, whose bottoms and tops are open, are arranged above working platforms 101 of the working benches 100. The loose plate subassemblies must be mounted in the open-bottom cassettes 3, and mounting fingers 34 (FIGS. 5.1 and 5.3) which project into the slots 33 in the partition walls 32 of the cassette 3 serve this purpose. These mounting fingers 34 consist of two spring steel tongues 34.1 and 34.2 with an intermediate rubber spring 34.3, and are actuated and inserted by means of a hydraulically controlled lever 35, which may be seen in FIG. 5.2. These mounting fingers are shifted in stations I or II such that the loose plates and separators are secured in the bilaterally open cassette 3.

After the filling of the cassettes 3 and the mounting of the plate subassemblies is accomplished in stations I and II, the turntable is rotated by one step and the cassette reaches the position III. The plate lugs 11, on which the pole bridges 14.1 of the end cells as well as the cell connectors 14 are to be welded, are aligned in position. For this purpose, a work bench 200 is provided, the work platform of which may be a vibration plate 201. In addition, gauges or strips 202 are provided which may be lowered so as to touch the plate lugs 11 of the electrode plates, and the plate lugs and electrode plates are aligned to form a single row thereby. It is important that the separators 13 protrude beyond the ends of the electrode plates 12 uniformly on both sides after the alignment operation is completed.

The mounting of the aligned but only partially mounted plate subassemblies is completed with the mounting fingers 34 projecting in the slots 33 in the cell partition walls 32 of the cassettes and being completely inserted by means of the hydraulically controlled lever 35.

In the next working step of the turntable 2, the cassette 3 reaches the work position IV, where a work bench 300 is provided, which has a testing device 302 which can be lowered to the cassette 3 resting on top of a work platform 301. In this position, the completeness of the electrode plates is tested. This can be done by, for instance, an arrangement of photocells or by means of mechanical testing pins in the testing device 302.

In the following working step, the work position V is reached. There, a cleaning of the plate lugs occurs. However, before that process, the cassette 3 is axially rotated 180° during its movement between the positions IV and V, by means of the spur gears 25 meshing with the gear segments 26 of the bridges 27. This rotation is indicated in FIG. 1 by the arrow 5 between the work stations IV and V.

A rotating brush 402 is provided on a work platform 401 of the work bench 400 in station V for cleaning the plate lugs 11. This brushing roller sweeps over the plate lugs at an angle of approximately 15° with respect to the central axis of the cassette. The cleaning effect is improved by this directional movement, and the plate lugs will not be bent as a result of the cleaning operation.

In station VI, which is reached in the next working step, there is provided a similar cleaning operation, but the brush therein moves at an angle of approximately 30° with respect to the position of the brush in station V, so that a complete cleaning of the plate lugs of the plate blocks is ensured as a result of the two cleaning operations, and all sides are cleaned uniformly.

In station VII, the plate lugs are treated with a fluxing medium, and there is provided a work bench 500 with a work platform 501, on which a container 502 with the fluxing medium is disposed, the plates being immersed therein. This container 502 can be lifted or lowered while cassette 3 is in this station VII, so that the plate lugs do not remain in the fluxing medium for the entire duration of this working step. Additionally, covers can be provided for the fluxing medium container 502 during the period when the medium is not in contact with the plate lugs.

In the next working step, station VIII is reached, where the plate lugs and the fluxing medium are heated to a temperature suitable for optimum performance by the medium. For this purpose, a work platform 601 of the work bench 600 forms a heating plate, so that the heating of the plate lugs may be accomplished by the passage of warm air thereby.

The next rotation of the turntable 2 moves the cassette 3 to the station IX, in which the cell connectors 14 and pole bridges 14.1 are joined to the subassembly. This station is shown in FIGS. 7.1 and 7.2 in greater detail, where FIG. 7.1 shows a cross-section and FIG. 7.2 a top view of the casting apparatus.

The casting device is arranged on the work bench 700 with the work platform 701, and it consists, in general, of a casting mold 702, in which all the cell connectors 14 and the pole bridges 14.1 are formed. In addition, there are provided lead metering and feeding devices 703, the lead feeding devices being connected with a lead supply container 7 by means of supply pipes (not shown in greater detail in FIG. 1). As the cassette 3 arrives at the casting station at the beginning of the work step, the mold 702, in the form of a strip with a uniform cross-section, is heated by a coil by connecting an electric current supply line to contacts 702 and to a connecting bridge 705. The heating duration is shortened significantly by utilizing the coil, and, in addition, the mold cools more rapidly, so that the step time can be significantly shortened as compared to the time required if the casting forms were heated by built-in heating coils or wires. For cooling the mold, there can be provided cooling ribs, and pipes 709 conducting compressed cooling air.

In order to form the lower undercut portion in the cell connector, which is already created during the casting process, and which is specified in FIG. 3.2 by numeral 14.2, which snugly receives the cell partition wall, there are provided blades 707 which can be inserted in the casting mold 702. They are actuated by rack and pinion and by hydraulic means. After the blades 707 are inserted, the casting mold is electrically heated to reach the temperature of 300° to 350°C. After that, liquid lead is poured into the mold, and containers 702 are moved above the casting molds 702. Two needle valves 706 are provided in each such container, and they serve to fill a mold for one cell connector 14, which is composed of two individual pole bridges and one cell connector with a central protruding member. The single containers are connected to the lead supplying container 7 (FIG. 1) by means of supply pipes which are not shown.

The cassette 3 is lowered after the container 703 has been removed, until the plate lugs are submerged in the liquid lead. Following the cooling process, the blades 707, which served the purpose of forming the lower undercut portion of the molded item, are retracted from the casting molds 702, and the cassette 3 can be lifted again, with the molded interconnected electrode assemblies from the casting molds 72 in the form of strips. The needle valves 706 in the lead containers 703 are time-controlled, and in order to ensure a complete filling of the mold, an additional supply of lead can be introduced into the mold after the initial heating and filling of the liquid lead has been completed.

The temperature measuring of the casting molds 702 is accomplished by means of a measuring device 708, which senses the longitudinal expansion thereof, and which simultaneously serves as a switch for the automatic control of the resistance or coil heating process. The plate subassemblies are now provided with cell connectors 14 and the pole bridge connectors 14.1, as well as terminal bolts.

As the turntable 2 moves, the cassette 3 moves to the next station X. During this movement, the cassette is rotated again by 180°, so that the cell connectors and the pole bridge connectors are on the upper side. Battery boxes are arranged on a work platform 801 of work bench 800 in station X, which are supplied from a storage device 6 (FIG. 1) by means of a conveyor belt 6a. The cell assemblies are clamped at the cell connectors and terminal bolts by claws 802. For instance, in case of a six-cell electric storage battery, there are provided six such claws on each side of the electric storage battery, and they are lowered simultaneously. Therefore, the 12 claws form a unitary unit.

An illustrative claw is shown in FIG. 8. It is provided at its lower end with jaws 804, which are driven by means of a torsion bar 805, gear 802 and rack 807, and which grasp the cell connectors or pole bridge connectors, respectively. As soon as the cell connectors or the pole bridge connector is firmly clamped, the mounting device in the cassette 3 is released as the fingers 34 are retracted, and the entire plate assembly supported on the claw is pressed through the cassette 3 and into the battery box positioned just below the cassette. In order to avoid canting of the lower parts of the cell assembly, and to ensure a clean insertion of the plate assemblies in the battery boxes, the cassette 3 is provided at its lower end below the partition walls with V-shaped receiving guiding strips 36.

AFter this step, the battery boxes, with inserted and mutually interconnected plate subassemblies, are transported to an injection molding apparatus 9 by means of a conveyor belt, where encasing of the cell connectors in the cell partition wall region by plastic material, the filling of the recess in the partition wall with plastic and the creation of the rib on top of the cell partition wall are performed.

The injection molding apparatus necessary for accomplishing this objective is shown in FIG. 9. The battery boxes 901 with the plate subassemblies are forwarded to the injection molding machine by means of a conveyor belt (not shown in a greater detail), and molds 902 are attached to the cell partition walls. A perspective view of the mold half is shown in FIG. 3.3. The mold halves are pushed together by means of actuators 905 and levers 903. At the same time, the lower and upper undercut portions of the cell connector 14 are created. The upper undercut portion is shown in FIG. 3.2 and specified as 14.3.

Above the mold, there is provided a distributing tool 906 to which the battery box is lifted by means of a hydraulic cylinder 907. Injection nozzles 908 feed into channels 909 of the molds, and the actual injection process occurs. As a supplement, the injection molding apparatus is provided with a device 910 for preparation of the plastic material, as well as for forwarding and heating this material, and also a controlling device 911.

After the injection molding is finished, the lid is attached to the battery box in an additional machine in accordance with the conventional mirror-welding process.

An advantage of the disclosed automatic machine resides in the fact that all the necessary pole bridge connectors and the cell connectors as well are simultaneously molded on the plate subassemblies, and that these mutually mechanically and electrically interconnected plate subassemblies are directly inserted in the battery box. Shortly thereafter, the encasing of the intercell connectors in plastic material follows, with the simultaneous filling of the recesses in the cell partition walls with plastic, so that a pre-heating of the cell connectors before the encasing may be eliminated as a result of the very short time required for these process steps.

The cassette for accommodating the plate subassemblies, as used in the machine, has the advantage that the plates and separators can be aligned in such a manner that the separator extends uniformly beyond the electrode plates on both sides thereof. All plate subassemblies pass through the various process steps in this mutual alignment of the plates and the separators.

FIG. 10 is a schematic diagram of an illustrative electrical circuit for automatically moving the turntable through its various working positions. Only three limit switches FC, GC, HC, of the three work stations VI, VII, VIII are shown to illustrate the operation of the electrical circuitry. When the work at each station is terminated, a switch is closed and energizes a relay R which closes its contact R1 and thereby energizes a contactor. The contacts C1 and C2 then energize the drive motor DM. A back contact C3 of the contactor C then opens and prevents the relay R from again changing state as long as the motor DM is in operation. The motor drives the table 2 through a step-down transmission SG, and also a cam S which, however, may also be mounted on the column 21 (if this column rotates together with the table 2). The cam closes a switch S1 which then keeps the contactor C picked up for one full rotation of the cam, thus determining the length of each step of table progression. Denoted by SL is a current supply line.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since changes may be made in the above apparatus without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.