Field of the Invention This process relates generally to electrochemical cells and batteries and, more specifically, to a method of manufacturing and otherwise preparing lead-acid battery grids and plates for use in constructing, and assembling, lead-acid batteries and other batteries utilizing plates so prepared.

Background of the Invention

The main method of lead-acid battery manufacturing and its attendant manufacturing steps is well known. The method is the Faure process (pasted plate process) .

To briefly summarize the Faure process, first, the plate frameworks, commonly referred to as grids, are manufactured. The methods most commonly used to manufacture the grids are casting, expansion, or punching operations. Typically the grid is formed of a metallic lead or lead-based alloy.

Second, a leady oxide paste is applied to the grid. Typically the paste contains 55-85 wt—% lead oxide and 45-15 wt% metallic lead. The paste may contain a variety of supplementary agents, such as fibrous bonding materials and the like. The paste usually varies depending on whether the plate is intended to be a negative or a positive plate.

Third, the paste, which has been applied to the grid, is "flash dried," a process which dries the exterior of the paste and is a precursor to the fourth step, curing, which consists of a much longer drying period under carefully controlled environmental conditions. After curing, the pasted plates are insulated with sheets ("leaves") , or envelopes, of an electrically nonconductive material. This separator material insulates the plates from plates of the opposite electrical polarity in the cells.

Fifth, groups of plates are assembled into a cell or battery container. A dilute acid electrolyte solution is then added to the container and an electric current is passed

through the plates to "form" (electrochemically convert the paste to electro-active material) the cell.

This process, especially in the manufacture, pasting and assembly of the grids, requires complex and costly ventilation to confine airborne lead particulates. The process also requires several plate handling steps. Due to the toxicity of lead, rigorous and stringent safety procedures are, therefore, required. Further, many of the steps of the process require complex and costly equipment, especially the manufacture of the grids.

As earlier described, there are three main methods of manufacturing grids. When casting is used, molten lead is poured into molds. Casting provides for complex shapes, but tight quality control, skilled labor, ventilation, high temperatures, and the addition of minor and/or trace elements to the molten lead (e.g., to allow the lead to be properly cast) are required. In the method by punching, there is a large amount of punching scraps produced. A large labor and energy cost is required to recover and refine the scrap, and material is wasted. In the expansion method, although substantially no scrap is produced per se by the process, there is still a high scrap rate due to punching out waste slugs between the grid lugs produced. Also, the process produces grids with sharp projections and/or protrusions which tend to puncture separators, thereby producing short circuits either in production or in use. Each of these three grid manufacturing methods requires expensive machinery.

Of the three manufacturing methods described above, casting is the most batch oriented, although advances have recently been made in the art to overcome this drawback. Adding to -the batch nature of casting is the need for some alloys to age or season prior to further processing. Punching and expanding are more continuous and one patent, U.S. Pat. No. 4,305,187, Iwamura et al, describes a method and apparatus for increasing the continuousness of manufacture by expanding.

Even with increases in continuousness, however, both punching and expanding processes suffer the drawbacks noted above.

A further drawback of prior art battery plate manufacturing processes, as also noted above, is that the steps of pasting, curing, installing the separators, grouping the plates, and placing the groups in containers require handling of the plates. Each handling of the plates increases the likelihood that personnel contact with lead will occur. Lead is a toxic substance, hence the goal is to avoid handling the same.

Typically in the art, immediately after pasting, regardless of the process used to manufacture the grids, the pasted plates are flash dried (optionally) and cured with concomitant drying prior to further handling to facilitate further assembly. This drying step is required due in part to a mechanical handling problem. Wet or damp plates tend to stick/adhere to one another. Also, some wet plates do not have the requisite mechanical rigidity to withstand the downstream manufacturing steps. Therefore, drying is required before subsequent manufacturing is possible. However, it would be desirable to work with the wet plates to eliminate the dangers of lead dust associated with dry plates.

Therefore, there is a need for a method to manufacture battery grids, plates and/or cells/batteries which eliminates the handling of plates, reduces the steps required to cure and form the plates, reduces scrap and lead exposure hazards, eliminates use of molten lead in the manufacturing process, and provides a continuous manufacturing process.

Summary of the Invention The present invention provides a relatively simple process to manufacture and otherwise fabricate battery grids and assemble them into plates for electrochemical cells and batteries. The process reduces scrap associated with conventional battery grid manufacturing processes, while eliminating casting, and thereby eliminating molten lead. The

process also increases the continuous nature of manufacture, reducing the "batch" nature of the several current battery manufacturing methods and minimizing or eliminating hazards from handling dried plates. Further, the process produces batteries with equivalent or increased performance and life expectancy of batteries manufactured using current methods.

The present inventive method for preparing electrochemical batteries comprises the following steps: first _τ optionally rolling a sheet of lead, lead alloy, titanium, tantalum or an alloy thereof (hereafter for convenience referred to in this application as "metal strip" unless otherwise provided) to an approximate uniform thickness. Alternatively, stock rolls of the foregoing materials may be purchased and utilized in the process.

Second, the metal strip is advanced as a sheet about its longitudinal axis to a first station. The first station comprises two counter-rotating opposing rollers. As the sheet of lead alloy moves forward, it is advanced between the two rollers. Each roller carries a series of deforming elevations ("cutter teeth") about its circumference which shape the sheet in an "interrupted corrugation" pattern with deformed portions selectively defining sheared slits. The first roller's cutter teeth intermesh with the second roller's cutter teeth in such a way (i.e., each tooth carried by the first roller is aligned over a spacing zone on the second roller and fully overlaps with at least one tooth carried by the second roller, between which teeth there is a shearing clearance) that the metal strip material is selectively sheared and deformed into a pattern of raised elevations, lowered elevations, and neutral areas with respect to the mean plane defined by the metal strip. (This pattern is herein referred to for convenience as "patterned" or as an "interrupted corrugation" pattern.) Located and formed selectively between the raised and lowered elevations are slits or holes through the strip.

Third, the metal strip is next moved to a pasting station wherein electrochemically active-material-precursor paste is applied to the interrupted, corrugated metal strip. The pasting station comprises a second set of counter-rotating opposing rollers and a supply of paste. The paste is applied to the metal strip in the nip of the rollers as in a roll- coating type operation. The metal strip may have an undeformed portion near its center which is not pasted. Additionally, the metal strip may be pasted (by divided rolls) with either similar or opposite polarities of paste. The set of rollers may be so adjusted as to slightly compress the deformed areas of the metal strip. This ensures that the paste is compressed through the selectively formed slits and that no voids or air pockets are located within the paste or between the paste and the metal strip. A light-weight, unsized paper may be added in the pasting step to the exterior of the paste to reduce lead dust and ensure that paste does not adhere to the rollers.

Fourth, the pasted metal strip is moved to a station comprising a cutting area. Here, the sheet is cut transversely to its longitudinal axis. The transverse cutting is done repeatedly at such intervals as are determined by the width of the plates for the cells to be made. The plates are either moved to a second cutting stage, or additionally cut simultaneously with the first cutting, wherein a series of cuts are made parallel and transverse to the sheet's longitudinal axis. The combined effect of the cutting makes one or more distinct, individual pasted battery plates for each longitudinal portion of metal strip. Preferably, two distinct plates are made for each such longitudinal portion.

Fifth, the plates are wrapped in insulating separator material as they proceed from the cutting stage. The plate's tab extends from the separator material.

Sixth, the plates are immediately assembled in groups without curing. As used herein, a group shall refer to at

least one or more negative plates and one or more positive plates within a cell (with appropriate insulation) .

Seventh, the tabs of the plates of like polarity within a group are combined (by electric, ultrasonic, or flame welding, mechanical crimping, or other means well known in the art) separately to become the cell terminals. The cell terminals may later be connected to adjacent cell(s) and cover(s) may then be applied by means which are well known in the art. Battery terminal inner posts may also be connected as required.

Subsequent to the group being placed in a cell container and connected, the cell may be cured as desired. After curing, the cell is filled with acid and an electric current is passed through the plates to "form" the cell.

Therefore, a feature of the present invention is that it provides for the continuous, conjoined and simultaneous manufacture of battery grids, plates, cells, and/or batteries, with no inherently necessary storage steps. Casting is eliminated. The process also allows working with wet plates to reduce or eliminate lead dust.

According to one aspect of the invention, there is provided a method for making grids for lead-acid storage cells sin a continuous fashion by advancing a metal sheet of lead or lead alloy through a step of forming a patterned array of raised, lowered, and neutral portions in the metal sheet, wherein said raised portion is above the plane formed by said sheet and the lowered portion is below the plane formed by said sheet and said raised, lowered, and neutral portions selectively define holes therebetween.

According to a further aspect of the invention, there is provided a method as recited above wherein the metal is formed by cutting said metal between two sets of toothed cutters. Still further, the raised and lowered portions form rows which are interleaved with rows of neutral areas which lie

substantially in the mean plane formed by the lead alloy sheet.

A further aspect of this invention provides a method of manufacturing lead-acid batteries comprising the steps of deforming and shearing metal in a plane generally perpendicular to its surface, applying a paste to the surface of the metal, applying nonconductive material between the plates either before or after curing said plates, grouping the plates, assembling the plates into a container, and "forming" the plates.

While the invention will be described with respect to a preferred embodiment method and with respect to particular components used therein, it will be understood that the invention is not to be construed as limited in any manner by either such embodiment or components described herein. Further, while a preferred embodiment of the invention will be described in relation to the manufacture of a lead or lead- alloy cell or battery or other fabrication of electrochemical devices, it will be understood that the scope of the invention is not to be limited in any way by the environment in which it is employed. Other devices utilizing a grid structure might include electrolytic capacitors, lightning arresters, and other primary or secondary cells besides the lead acid type. The principles of this invention, however, are particularly well suited to the fabrication of electrochemical cell batteries so as to improve continuity of manufacture, reduce scrap, eliminate the requirement for molten lead, and reduce the handling of plates. These and other variations of the invention will become apparent to those skilled in the art upon a more detailed description of the invention.

Various advantages and features which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objectives obtained by its use, reference should be had to the

Drawings which form a further part hereof and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.

Brief Description of the Drawings

Referring to the Drawing, wherein like numerals represent like parts throughout the several views:

FIGURE 1 is a block diagram identifying the steps of a preferred method configuration that practices the principles of this invention;

FIGURE 2 is a. schematic representation of several of the steps illustrated in Fig. 1;

FIGURE 3 is a perspective view of a deforming and cutting station 30 of Fig. 1;

FIGURE 4 is a perspective partially exploded view of a portion of rollers 300 and 400 of Fig. 3;

FIGURE 5a is cross-sectional view taken in elevation with portions broken way of rollers 300 and 400 of Fig. 2;

FIGURE 5b is a top enlarged view of a portion of rollers 300 and 400 of Fig. 2;

FIGURE 5c is an end elevation view of disks 301, 302, 401 and 402 which comprise rollers 300 and 400 of Fig. 2;

FIGURE 6 is a top view of a pasting station 40 of Fig. 1;

FIGURE 7 is a front view with portions broken away of pasting station 40 of Fig. 6;

FIGURE 8 is a side view taken through line 8-8 of Fig. 6 of pasting station 40 of Fig. 6;

FIGURE 9 is a- top view of a sheet of lead alloy just previous to entering station 50;

FIGURE 10 is a perspective view of several plates 510 interleaved after assembling at station 70 of Fig. 1 (with accompanying separators omitted, for clarity) ;

FIGURE 11 is a perspective view of the several plates 510 of Fig. 10 with portions broken away and with tabs 504 connected;

FIGURE 12 is a side view of a grid 500 manufacture according to the principles of the present invention take through line 12-12 of Fig. 13;

FIGURE 13 is a bottom view of the grid 500 of Fig. 1 taken through line 13-13 of Fig. 12;

FIGURE 14 is a perspective view of a portion of the gri 500 of Fig. 12;

FIGURE 15 is a front view taken in elevation of the grid 500 of Fig. 12;

FIGURE 16 is a perspective view with portions broken away of a battery manufactured according to the principles of the present invention; and

FIGURE 17 is a view of two disks in overlap

Detailed Description of the-Preferred Embodiments As mentioned above, the principles of this invention apply to the manufacture and other fabrication of electrochemical cells and batteries. This invention provides an improvement in the continuousness of the manufacturing process of electrochemical cells and batteries. This invention also reduces scrap in the manufacture of the battery grids, reduces the handling of dry plates, and eliminates the need for molten lead (or molten lead alloy) since casting is not performed. A preferred application for this invention is in the manufacture of lead and lead alloy lead-acid cells and batteries. Such application, however, is typical of only one of innumerable types of applications in which the principles of the present invention can be employed.

Referring first to Figs. 1 and 2 of the Drawings, wherein like numerals represent like parts throughout the several Figures, there is illustrated a continuous method, employing several stations, for the manufacture of lead-acid cells and batteries. First is an optional rolling station 20 (not shown in Fig. 2) , second is an opposing counter-rotating toothed roller deforming and cutting station 30, third is a pasting station 40, fourth is a cutting station 50, fifth is an

enveloping station 60, sixth is an assembling station 70, seventh is an optional curing station 75 (not shown in Fig. 2) and eighth is a formation station 80 (not shown in Fig. 2) . At assembly station 70, the connecting tabs of plates of like polarity are connected by one of several well known methods and placed in containers. At optional curing station 75 the plates are allowed to further dry or cure as is well known in the art. An electric current is then passed through the plates at formation station 80 in order to "form" the cells.

The various stations will first each be described in order to gain an understanding of the present invention. A presentation and description of various test results of a cell and/or battery manufactured according to the principles of the present invention will be deferred until further below. Additionally, the detailed description of a grid manufactured according to the principles of the present invention will similarly be deferred until the manufacturing process is described.

It should also be noted that no attempt will be made to correlate in the Figures each of the disks 301, 302, 401 and 402 or teeth 310, 410 to those represented in the Figures. Those skilled in the art will recognize that the actual number of teeth and disks are design considerations.

The first step in the preferred manufacturing process is an optional rolling station. Optional rolling station 20 may comprise two opposing rollers (not shown) , made of steel or other suitable material, wherein lead, lead alloy stock, or other suitable transition nfetal or transition metal alloy (as noted above referred to herein as "metal strip" 22 for convenience) , may be rolled to an approximate uniform thickness. The stock metal strip 22 provides the material from which the lead-acid cell battery grids are to be manufactured. The stock is rolled to the desired thickness taking into account both the downstream manufacturing steps described below and the expected end use of the cell or

battery. For example, those skilled in the art will recognize that a thicker grid provides greater grid conductivity and longer grid life. Alternatively, a thinner grid provides lighter cell weight.

In the preferred embodiment, the range of grid thickness is approximately 15/1000 to 20/1000 inch. However, this thickness may range from 5/1000 to 30/1000 or more, several of the design considerations being ease of handling in fabrication, end weight, and overall economics. The metal strip 22 is either rolled between the opposing counter- rotating rollers of station 20, or alternatively, the metal strip 22 may be purchased as a uniform thickness stock 21 (best seen in Fig. 2) . Those skilled in the art will recognize that rolling metals and alloys to a uniform thickness is well known in the art and accordingly will not be described further herein. While preferably the metal strip 22 has a uniform thickness or thickness profile, those skilled in the art will recognize that such thickness may be variable within certain ranges. Also, the metal strip 22 may be surface treated or textured as desired.

The metal strip 22, which now comprises a desired cross section and has a predetermined transverse width, is then moved as a sheet from roller station 20 about its longitudinal axis, or rolled as a sheet from stock 21 (as best seen in Fig. 2) , to the second station 30. In the preferred embodiment, this second station 30 forms a matrix or pattern of alternating rows of abutting raised and lowered elevations, or portions, wherein the raised portion is above, and the lowered portion is below the mean plane formed by the metal strip 22 (where the metal strip 22 is horizontal) . Further, slits are selectively formed in the metal strip 22 by second station 30. These slits lie generally normal to the mean plane formed by metal strip 22. A grid embodying these characteristics may best be seen in Figs. 12-15 and further described below.

The metal strip 22 may be considered to form an X-Y plane with the strip's 22 direction of travel being in the X direction and the transverse width being in the Y direction. A Z direction (perpendicular to the X-Y plane) is the direction in which strip 22 is deformed, and the slits are generally aligned parallel to the Z axis. Those skilled in the art will appreciate that the ability to provide slits or holes without producing scrap is a significant benefit.

As illustrated in Figs. 3, 4 and 5, station 30 comprises a selective deforming ans shearing station; the function of which is to selectively deform portions of the metal strip 22 out of the mean plane defined by the metal strip 22 and selectively to shear portions of the metal strip 22 to form slits. In the preferred embodiment, two side-by-side counter- rotating rollers 300 and 400 are used as means for deforming the metal strip 22. The rollers 300 and 400 are preferably comprised of a plurality of steel disks. The periphery of the disks form the roller 300, 400 surfaces. Each of the set of disks which comprise one of the rollers 300, 400 will be referred to herein as a series. Therefore, there is a first series 300 and a second series 400 of disks.

Within each of the series 300 and 400, the disks alternate between support disks 301 and 401 which support the metal strip 22 ("spacers") and deforming/shearing disks 302 and 402 carrying deforming teeth 310, 410 about their circumference ("cutters") .

Referring now to Figs. 5a and 5b, the two series 300 and 400 "intermesh" and overlap such that the first series' 300 spacers 301 are oppositely aligned with the second series' 400 cutters 402. Similarly, spacers 401 on the second series 400 are aligned with cutters 302 on the first series 300. The cutting teeth 310 of the first series 300 overlap and cutting teeth 410 of the second series 400. The cutting teeth 310, 410 do not "mesh" in the usual gear sense, but rather overlap and shear the metal strip 22 as they approach into and recede

from overlap. Overlap, as best seen in Fig. 17, may be defined as the area between the two planes tangent to the support disks 301 and 401 and perpendicular to the line joining the center axes of mandrels 315, 415, the planes formed by the lines of intersection of the teeth 310, 410 with the metal strip 22, and bounded by the end of the mandrels 315, 415. A tooth 310, 410 is in overlap when it intersects this area.

The teeth 310, 410 are not immediately adjacent to one another when in overlap, but instead have a shearing clearance distance between them. The teeth 310, 410 also have an overlap which is the distance J between the tips of the two teeth 310, 410 when fully in overlap. By appropriately determining the overlap between the adjacent cutting teeth 310, 410, slits may be selectively formed in the metal strip 22 by a shearing action as will be further described below.

As best illustrated in Figs. 5a and 5b, it can be seen that, as noted above, each disk of the first series 300 is aligned with a corresponding disk of the second series 400 (e.g., spacer 301a is aligned with cutter 402a, etc.). The alignment between the corresponding disks includes: the disks' radial axes are parallel, the circumference of the disks are in close proximity allowing for the metal strip 22 thickness, and the disks' side radial surface lie nearly within the same plane (the cutters 302, 402 are slightly narrower K, Fig. 5b, typically 0.001-0.002 inch, than the spacers 301, 401 to avoid interfering with one another) . An end elevation view of the two types of disks is provided in Fig. 5c.

Referring still to Fig. 5b, in the preferred embodiment of station 30, the shearing clearance K is the space between the opposing sets of cutters 302, 402. The thickness/face- width L of cutters 302, 402 is approximately 1/8 inch, although varying sizes may be used. The thickness/face-width ^~ M of spacers 301, 401 is also preferably approximately 1/8

inch. The clearance space N between the sets of the tips of cutting teeth 310, 410 and spacers 301, 401, where the peak of the deformed portions of the metal strip 22 is made, is variable, but preferably is no smaller than the thickness of the metal strip.

The two series 300, 400 of disks are carried by mandrels 315 and 415 respectively. The mandrels 315, 415 are rotatably mounted in a supporting frame 31, as further described below. The plurality of disks 301, 302, 401 and 402 are firmly engaged to the mandrel of keyways 316 and 416 and keys 317 and 417 respectively. Preferably the disks have a thickness of 1/8 to 1/2 inch, an interior diameter of 4.906, and pitch circle diameter of 5.000 inches. The teeth 310, 410 on the tooth-carrying disks 302, 402 are located 0.1309 inch apart on the periphery of the disks 305, 306 and are 0.0750 inch in height. The teeth 310, 410 extend somewhat obliquely from their tips (best seen in Fig. 5a) to the periphery of the disks 302, 402 to prevent tearing the metal strip 22, and have a slightly rounded tip. The teeth 310, 410 have a sharp side radial edge to promote shearing.

In an alternate embodiment (not shown) station 30 again comprises a first series and second series of alternating disks/gears. The alternating disks for the purpose of the second embodiment will be referred to herein as full-height gears and half-height gears. In the full-height gear, the dedendu portion of alternate teeth are removed. In the half- height gear, alternate teeth are cut to the pitch circle, while the remaining teeth are removed to the clearance circle. Full-height gears are interleaved in each series with half- height gears. In the two series, the full-height gears of the first series are opposed to the half-height gears in the second series, and conversely. This provides for the full- height gears of the first and second series to overlap side- by-side, thereby deforming a metal strip placed immediately therebetween.

By overlapping the teeth immediately adjacent to one another, the deformed areas alternate immediately adjacent to one another and the metal strip 22 is selectively sheared in these adjacent areas dependent upon the clearance between the meshing gears. Preferably, as noted above, the sheared portions of the metal strip 22 form a hole which is approximately circular, the hole being aligned approximately normal to the _. mean (X-Y) plane of the metal strip. Those skilled in the art will recognize that other arrangements of gears could produce similar patterns.

Using either method, the overlapping action preferably provides an "interrupted corrugated" pattern with raised and lowered deformed areas, neutral areas, and sheared slits or holes selectively defined between the adjacent lowered and raised areas. A copending and commonly assigned application describing a battery grid comprising such characteristics is Serial No. 270,244, entitled "Improved Lead-Acid Storage Cell Grid," which is hereby incorporated by reference. As noted, a brief description of such a gird is also provided below. However, to further describe station 30, a brief correlation between a grid 500 (as illustrated in Figs. 12-15) and the disk sets 300, 400 follows.

Running between the rows of alternating raised 502 and lowered 501 portions of the grid 500, in the preferred embodiment, is an area, or row, 503 which is substantially neutral in elevation with respect to the mean plane defined by the metal strip 22. In the preferred station 30 embodiment, this portion of the grid 500 corresponds to that area of the periphery of cutting-tooth-carrying disk 302, 402 between the teeth 310, 410. In the alternative station 30 embodiment, this portion corresponds to that area where the teeth cut to the pitch circle have meshed. These neutral rows 503 form paths which run transversely to the direction of travel of the metal strip 22. Therefore, the grid 500 matrix or pattern, running transverse to the longitudinal direction of travel,

comprises the interleaved rows of alternating raised 502 and lowered 501 portions (with slits 504 formed selectively therein) and neutral rows 503. These rows are established in the metal strip/grid 500 by the rollers 300, 400.

The above described neutral rows 503 serve the function of acting as current paths in the battery plate, while the raised 502 and lowered 501 portions provide greater surface area, area closer to the electrochemical process to gather the current, and means of securing active-material paste to the grid. It will be appreciated by those skilled in the art that the width of neutral rows 503 may be adjusted by adjusting the distance between cutting teeth 310, 410, while the depth of the raised 502 and lowered 501 portions may be adjusted by adjusting the height of the cutting teeth. Further, those skilled in the art will recognize that the slits 504 might also be located at various intervals or between various elevational portions as a matter of design. Neutral areas 503 might also be interposed between raised 502 and 501 elevations and still remain within the purview of the present invention. The raised 502 and lowered 501 portions might also be deformed by means of a press type process, as those skilled will recognize. Further, those skilled in the art will recognize that, in lieu of disks, a solid roller with protrusions, or an assemblage of multiple-row sub-cutters might also be utilized.

The deformed slits 504 provide means for fibrous bonding material added to the paste 600 to bond the paste 600 on one side of the grid strip 601 to the paste 600 on the other side of the grid strip 601. This bonding between the paste 600 on the two sides of the grid 601 provides a more solidly pasted plate to avoid blistering and shedding during service life. Pasting is further described below.

In the preferred embodiment, a gap 305 and 405 is interposed within each of the two different series of disks 300, 400. The gaps 305, 405 provide for an unworked/undeformed area in the metal strip 22. This enables

the simultaneous manufacture of two grids 500 for each transverse section of the metal strip 22, best seen in Fig. 9. This area later comprises the battery plate tabs 504. However, those skilled in the art will recognize that the gaps 305, 405, providing the unworked area, could be provided for on either side of the battery plate 510, or that a single row of battery plates 510 may be manufactured at one time. The gap could also be a sleeve (not shown) which supports the metal strip 22. Since the strip 22 is being slightly shortened in the X direction by the deformation process, sleeves aid in avoiding the wrinkling of the undeformed portion of strip 22.

The rotation of series 300 and 400 are coordinated by timing gears 306, 406. The series 300, 400 are driven by any suitable form of power (such as a gear head motor 307 and sprocket chain 308) . In the preferred embodiment a 1- horsepower 460-volt motor manufactured by Dayton Electric of Chicago, Illinois, is used. Those skilled in the art will recognize that innumerable power sources might be utilized.

In operation series 300, 400 are driven by motor 307 to counter rotate the series 300, 400 thereby drawing the metal strip 22 therebetween.

The series are mounted in a box shaped steel frame 31 which is open on two sides (i.e., the top and bottom) to allow for the introduction and removal of the metal strip 22. Preferably, the box is made of two U-shaped sections 31a, 31b which may be bolted together. By constructing the box in a U- shape, the overlap (depth of engagement) between the series 300, 400 may be adjusted by inserting shims between the U- sections 31a, 31b. A more detailed description of station 30 is set forth in copending and commonly assigned application Serial No. 270,245, titled "Deforming and Shearing Roller Apparatus", which is hereby incorporated by reference.

The metal strip 22 moves from the deforming station 30 to the pasting station 40 which is best seen in Figs. 6, 7 and 8.

Here, a leady oxide paste 600 is applied to the metal strip 22. The paste may contain a variety of auxiliary agents, such as expanders and the like. Paste 600a and past 600b may be alike or distinct, as required by downstream considerations. In the preferred embodiment the paste consists of leady lead oxide "litharge" (containing 15-25 wt-% metallic lead) , sulfuric acid, and contains approximately 7 to 8.5 wt-% water and, in the case of the negative paste, an "expander" additive of lignosulfonates, carbon black, and barium sulfate. Those skilled in the art will recognize that the composition and making of paste are well known in the art and will not be further described.

The pasting station 40 comprises two counter-rotating opposed steel rollers 41a, 41b between which the "interrupted corrugated" metal strip 22 is drawn. The paste 600 is applied to both sides of the metal strip 22, on those areas which have been corrugated, at the nip area 42 of the counter-rotating rollers 41, by passing the metal strip 22 through a paste supply container 43. The movement of the strip 22 through the paste supply 43 and the squeezing action of the rollers 41a, 41b provide the required turbulence or agitation in the paste 600 such that the paste 600 is uniformly spread over the metal strip 22. In essence, the application of the paste 600 to the sheet 22, in the preferred embodiment, may be considered a form of roll-coating. However, other forms of coating, including blade application and moving-belt pasting, which are well known to those skilled in the art, may be used.

The paste 600 and metal strip move between the rollers 41 and are compressed by the rollers 41, thereby ensuring that the paste 600 is spread uniformly over the corrugated portions of the metal strip 22 and is extended through the slits 505 defined by the sheared sections. In the preferred embodiment, the rollers 41 may slightly compress the corrugated portions of the metal strip 22. The metal strip 22 recovers from the compression of the rollers 41 in a rebound manner, the extent

of the recovery being dependent upon the alloy used and the amount of compression; these functions being design considerations of the battery or cell 511. By judicious use of this compression and adjustment of the clearance between the rollers 41, plates of various thickness can be readily made.

In the preferred embodiment, positive and negative plates 510 may be simultaneously produced by providing differing pastes in the paste supply locations 43a, 43b. As noted, the positive paste is a mixture of leady oxide, water and sulfuric acid. The negative paste is a mixture of leady oxide, water, sulfuric acid and expander material.

The pasting station 40 may be constructed similar to station 30. That is, the frame of station 40 may be box shaped (not shown) with an open top and bottom. The box may be formed by placing two U-shaped pieces together. Further, a motor (not shown) may drive roller 41a and timing gears (not shown) to provide equivalent counter rotation between rollers 41. This drive is described in connection with station 30 above. Similarly, shims (not shown) may be placed between the U-shaped frame pieces to provide the appropriate clearance between the rollers 41. Those skilled in the art will recognize that these details may be modified without changing the scope of the invention.

Paste locations 43 each comprise four paste enclosure walls 44 to act as dividers. The walls are shaped (best seen in Fig. 8) so as to provide paste 600 to the nip 42 of the rollers 41 and maintain the- paste 600 in a supply location 43. Threaded rod 45 and appropriate fastening means such as nuts and washers may act as a support and spacing means for the walls 44.

Additionally, station 40 provides a light-weight unsized paper 47 at four supply roll locations 46 to prevent the paste 600 from sticking to the rollers 41, reduce lead alloy dust and facilitate further handling. Preferably the tissue paper

47 breaks up in the formation acid and settles out. At that time the paper 47 may then be disposed of if so desired. In the preferred embodiment, the paper 47 is an unsized, 8-lb. tissue manufactured by Crystal Tissue Co. , Middleton, Ohio, designated as "Crystex" battery tissue.

The patterned and pasted metal strip 22 (referred to in this condition for convenience as the PAPMS 601) is then moved to the cutting station 50. As best seen in Fig. 9, in this step, the PAPMS 601 is cut transversely to the PAPMS's longitudinal axis (Y direction) to the desired width of the battery plate 510. Preferred cuts are indicated in Fig. 9 with hatched lines. In the preferred embodiment, there is also a series of cuts made to the center portion along the lead alloy's longitudinal axis. This provides for manufacturing two plates 510 in each transverse section of PAPMS 601 alloy. As noted, cutting may be done by a shearing type operation or steel rule die, as is well known in the art.

One or both series of the cut plates are then placed in nonconductive material 602, preferably folded into envelopes. This may be done by conventional means well known to those skilled in the art. An example of such an enveloping machine is a Tek-Max manufactured by the Texmax Co. , Corvallis, Oregon, designated by model number 85. The nonconductive material 602 is preferably a porous polyethylene, but may be of any material which is porous, , nonconductive and does not break down in sulfuric acid. An example of such a material is Grace "Daramic" 200 MR, manufactured by W. R. Grace & Co., Lexington, Mass.

The cut and insulated plates 510 are then assembled with positive 510a and negative plates 510b interleaved with one another. - For example, the adjacent plates 510a and 510b are placed with the face of plate 510a abutting the face of plate 510b. The tabs 504a of one polarity are aligned with one another and away from the tabs 504b of opposite polarity. This may be best seen in Figs. 10 and 11. The tabs 504 of the

plates 510 of like polarity are then combined by electric, ultrasonic or flame welding, mechanical crimping or othe means well known in the art, as shown in Fig. 11. Th connected tabs 504 of one polarity become the cell terminal 512 of that polarity. Cell terminals 512 may then be connected to adjacent cells (not shown) and covers 513 may then be applied by means which are well known in the art. Battery terminal inner posts may also be connected as desired.

Alternatively tabs 510 may be constructed by cutting, partially, the grid along the top edge in the X direction. By then folding the resultant strip down and up, an integral tab results. Those skilled in the art will recognize that other arrangements of cuts and/or folds might be performed to produce tabs 510.

To assemble the cut plates 510 may be removed (parallel to the Y axis) and placed in envelope 602 material. If plates 510 of opposite polarity are being simultaneously made, one need only turn one plate 510 to align its tab 504 prior to assembling. A suitable battery casing on an indexing elevator may then be used for placement of the assembled cell. Preferably prior to interleaving, tab 504 shaping is done to facilitate connection with tabs 504 of like polarity.

The plates 510 are thus assembled in groups and are placed in the cell container before any optional curing at stage 75. Since this invention does not deal with curing per se, but rather with when and where curing occurs, curing will not be discussed in detail. Curing is well known in the art and is described in U.S. Pat. No. 4,713,304; Hand Bode, Lead Acid Batteries. Chapter 3.3, (Interscience Series, Wiley & Sons, 1977) ; and in Nels Hehner, Storage Battery Manufacturing Manual III. (3rd Ed. , Independent Battery Manufacturers Association, Inc.) at pp. 28-30, which are hereby incorporated by reference.

After any such optional curing, the cell is filled with dilute sulfuric acid solution and an electric current is

passed through the plates to "form" the cell. Once the cell is "formed," the dilute acid may be removed and a more concentrated sulfuric acid solution may then be added and the cell fully charged, as is well known in the art.

In another well known method of formation, commonly known as "one-shot," higher concentration sulfuric acid solution is utilized; this solution (which becomes converted into the working battery concentration during formation) remains in the completed cell. Again, this invention does not deal with formation per se and formation is well known in the art. Formation will not be described further herein.

Next, a description of the text results of cells and batteries manufactured according to the preceding process will be described. Such cells and batteries have achieved equivalent or increased performance and life expectancy of batteries manufactured using current manufacturing methods.

The Battery Council International (BCI) has issued storage battery test specifications to provide meaningful measurements of battery performance. The test sequence consists of 5 tests as follows: (1) reserve capacity test, (2) cold cranking test, (3) reserve capacity test, (4) cold cranking test, and (5) reserve capacity test. The reserve capacity test is defined as the number of minutes a new fully charged battery at 80°F. (26.7°C.) can be discharged at 25 amperes and maintain a voltage of 1.75 volts per cell or higher. The cold-cranking test is defined as the discharge load in amperes which a battery at 0 ^C F. (-17.8°C) can deliver for 30 seconds and maintain a voltage of 1.2 volts per cell or higher.

The following table lists illustrative test results of cells and batteries manufactured according to the principles of this invention.

Table l

Each of the above tests denominated by a plate thickness refers to an individual single cell constructed of ten plates, comprising five positive and five negative plates. The foregoing table is set forth for the purpose of illustration and should not be construed as limiting this invention in any way. The grids utilized in the cells were manufactured using 1/4-inch cutting-tooth face width.

Using 1/8 inch (nominal) cutting-tooth face width in ten- plate single cells the following results were achieved:

Table 2 1/8 Inch Tooth-Width Corrugations

R/C Min Cold Crank Corrected Text, (A) 1 1 1 1 !

86.2 92.4 96.2 463 463 93.5 101.2 102.1 569 440

Another test which is used to evaluate batteries is the starting, lighting, ignition battery cycle life test. The test and representative results are as follows for a "corrugated pattern" battery, constructed according to the principles of the present invention, and several other batteries using common construction techniques for comparison purposes.

Table 3

Starting, Lighting, Ignition Battery

Cycle-Life Test Test Steps

(1) Discharge 4.0 sec. at 250 — 1% A

(2) Charge 26 sec at 15.00 — 0.05 V Constant Potential

(3) Repeat steps (1) and (2) , counting the total number of discharges until the end-of-discharge voltage falls below 1.60 V/cell.

Test Results

Expanded Ca Neg/Cast Sb Pos 116,034 cycles

Expanded Ca Neg/Expanded Ca Pos 40,137 cycles

Cast Ca Neg/Cast Ca Pos 96,720 cycles

Predetermined Sheared Patterned Pb Pos 174,456 cycles

The above results are shown for the purposes of illustration and are illustrative samples only. Other batteries constructed according to the principles of this

invention have similarly been tested in this manner and several have achieved greater than or equal to 100,000 cycles.

Each of the above results were obtained using a lead 8 pp w copper alloy.

Next, a grid manufactured according to the principles of the present invention will be more fully described, the grid being best seen in Figs. 11-14. In Fig. 15, a battery grid

500 is illustrated which is created by deforming and shearing station 30 and cutting station 50. Preferably the grid 500 is approximately 4-1/2 inches high by 5-5/8 inches wide with a cross-sectional thickness of 0.015 inches prior to elevating

501 and lowering 502 the deformities. The tab 504 which is formed as an integral portion of the grid 500 as described above is approximately 2-1/2 inches by 3 inches. Each of the foregoing measurements is illustrative only, the tab 504 area being governed in part by current carrying considerations which are well known in the art. This provides for a clearance of 5/8 inch between tabs 504a and 504b (best seen in Fig. 9) from which minimal scrap is generated.

Next, with reference to Fig. 13, there is illustrated a side view of a grid 500 taken in elevation. Each column of raised 502 and/or lowered 501 areas may be viewed as half-wave sinusoidal. The adjacent column of areas are of a half-wave sinusoidal shape as well as shifted one-half wavelength so as to correspond. Other shifts may be used to achieve a zig-zag pattern row as further described below. As used herein, the term sinusoidal is used to generally describe the rounded shape of the raised and lowered areas as they depart perpendicularly from the neutral plane (in Fig. 13 defined by the neutral portions 503) , reach an apex, and return to the neutral plane. Those skilled in the art will recognize that the shape may depend upon several factors including the method of manufacture (i.e., shape of rolling or pressing apparatus utilized) , the tensile strength of the material from which the battery grid 500 is manufactured, and the desired thickness of

the resultant grid and plate. Those skilled in the art will also recognize that the shape may vary from the semi- cylindrical lobes of the preferred embodiment to ovals, squares and other shapes.

In an alternative embodiment (not shown) , other wav shifts, particularly — 90° (i.e., a quarter-wave shift), ma be used. The resulting delimited pattern provides for a zig zag or serpentine row of raised and lowered abutting portions. The current carrying area may similarly zig-zag (o serpentine) so as to correspond, or may form straight rows between the zig-zagged raised and lowered portions.

Referring next to Fig. 12, there is illustrated a botto view of a battery grid 500. It can be easily recognized tha viewing the raised 502, lowered 501 and neutral 503 rows fro this perspective provides a "square wave" type configuration. In this view the section shown is taken along a neutral ro 503.

As noted above, located between the raised 502 an lowered 501 areas are selectively defined slits 504, seen bes in Figs. 13 and 14. Since the slits 504 are defined by semi- cylindrical raised 502 and lowered 501 portions, the slits 504 are actually two generally semi-cylindrical portions place together along their joint diameter.

Use of the process hereinabove described allows use o otherwise intractable alloys. The present inventio especially adds stiffness to such a grid by providing a rigi geometry. Therefore, use of a process according to th principles of the present invention allows use of alloys whic previously could not be used due to mechanical concerns. Further, the solid geometry provides a small distance to meta conductors from the active electrochemical reactants. Thi distance, it is believed, is responsible for the batterie constructed according to the principles of the presen invention to produce equivalent or increased performanc relative to conventionally constructed batteries. Thi

distance has recently been shown to be important. See, e.g., Marimoto et al. Computer Simulation of lead Discharge, 135 J. Electrochemical Society 293 (1987) .

It is to be understood that even though numerou characteristics and advantages of the present invention hav been set forth in the foregoing description, together wit details of the structure and function of the invention, disclosure is illustrative only. Those skilled in the art, for example, will recognize that the process could be adapted to a Plante process. Other modifications and alterations are well within the knowledge of those skilled in the art and are to be included within the broad general meaning of the terms to which the appended claims are expressed. It should be noted that lead and/or lead alloy includes at least lead which is pure, and high-purity, trace-additive, and minor- constituent lead alloys as those terms are known in the art.

It is to be understood that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only and changes may be made in detail, especially in matters of the method of applying the paste, the procedure for manufacturing the matrix of raised, lowered and neutral portions of the grid (matrix should not be constructed as limiting in a two-dimensional sense as used herein) , and the manufacturing of one or more grids/plates, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.