Note: Descriptions are shown in the official language in which they were submitted.
816
The invention relates to a multi-cell lead storage battery
with electrode stacks positioned within a block casing. In particular, -
the invention relates to a battery intended for vehicular use, e.g. as
starter battery.
In the storage battery technology, most advances have
; preferentially benefitted the final product. For example~ most recently
; it has proven possible to achieve considerable product-related advances
and quality improvements through development of a low-maintenance lead
battery~ or through the introduction of a lightweight synthetic casing
for starter batteries in place of the previously conventional hard
rubber casing.
In contrast, the manufacturing process still remains composed
largely of the conventional manufacturing stages, such as grid casting,
pasting, forming, assembling, and insertion of the plate stacks, etc.
Despite machine assistance~ many process steps must still be performed
by hand, and even on individual electrodes, so that the manufacturing
process has generally remained discontinuous, thereby placing a ceiling
upon increases in productivity.
More rational manufacturing techniques have found application
only for the so-called smaIl batteries~ which~ in any event, were more
readily adapted for mass production. This includes the frequently
utilized equipping of both small alkaline batteries and s~aIl lead
battery cells with wrapped electrode stacks. In these, a positive and
a negative electrode strip are wrapped into an electrode spiral ~ith
interposition of a s~parator, and then inserted into the cell container.
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The edges of the electrodes are provided with connectors leading to the out-
side of the container. Because of the complexity of the connector lead-
throughs, such wrapped electrode stacks are generally used only for single-
cell batteries.
For electrode plates, too, there must not be overlooked a definite
trend toward replacement of the heavy mass supports, i.e. the cast lead grids,
by means of lighter structural frameworks, such as expanded metal. Moreover,
expanded metal can be manufactured as a continuous strip.
However, in and of themselves, electrode plates which are manufac-
tured using expanded metal, and which are packaged in stacks and then are
inserted in conventional manner into the upwardly open block casings that must
then be covered in conventional manner, do not represent a breakthrough in
progress toward smooth continuous work flow.
Accordingly, it is a purpose of this invention to provide a lead
storage battery which is more suitable than heretofore for rational mass
production. It is another purpose to provide the manufacturing process for
such a storage battery.
These and other objects which will appear are accomplished in
accordance with the invention by effecting the block casing closure by means
of a side wall.
This invention relates to a multi-cell storage battery having
electrode stacks comprising positive and negative strip electrodes with
intervening separator folded in a zig-zag configuration into a package,
wherein the adjacent individual cells are electrically connected via an
electrode support frame of one of the strip electrodes extending by means of a
large-surface portion across a cell separating partition, and the block casing
closure is formed by a side wall perpendicular to the plane of the electrodes.
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This invention further relates to the method of manufacturing,
which method comprises introducing the electrode stacks made of strip elec-
trodes folded in zig-zag configuration into a multicell block casing through
openings in the side of the casing, and closing this side of the block casing
in liquid-tight manner by welding a side wall to said block casing.
In a preferred embodiment of the storage battery embodying the
invention, each plate stack forming part of a cell consists of positive and
negative strip electrodes with interposed strip-like separators which have
been folded into a package with zig-zag configuration. Both the connection of
the cells to each other as well as the external electrical connection is
provided by means of large-surface portions of one of the
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two electrode support frames extending across the cell separating partitions
or the casing walls. These portions are positioned in the plane of closure of
the block casing, which is closed in liquid-tight manner by means of a side
wall, using mirror welding.
Further details concerning the invention and the process
embodying the invention are presented in what follows and in the accompanying
single figure of drawing.
This drawing schematically illustrates a two-cell storage
batterybaock casing 1, lying on its side, with an electrode stack according
to the invention~ which consists of strip electrode 12~ strip electrode 13
and the interposed separator strip 4 with ribs or lands 5. These are
folded in zig-zag configuration into packages and~ so packaged, are in-
troduced into the storage battery cells from the side. The folded edges 6
of the electrode packages are perpendicular to the bottom surface of the
storage battery, so that gas bubbles can rise unimpeded between the
electrodes.
In accordance with the invention, both the connection of
the cells to each other and also the external connection takes place by
means of large-surface portion 9 of the electrode support frame of one of
the strip electrodes, extending across the cell separating partition 7 or
the outer wall 8, respectively, of the block casing. For example, in the
drawing the external connections (16) and (17) are formed by the support
frame of the strip electrode (2), whereas the connection between the cells
is effected by the support frame (3) of the strip electrode (13).
The respective electrode strip may also be wrapped at its
end over a lead rod (not shown)~ and may be connected thereto in electrically
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conductive manner, e.g. by pressure welding. Starting from this rod, a
pole lead-through can then be provided in known manner.
The counter electrode and separator are interrupted in the
connecting region between cells, as indicated by dotted lines in the
drawing.
To manufacture a zig-zag folded electrode package according
to the invention for a multi-cell storage battery, one preferably starts
with electrode support frames 2, 3 which are wound as continuous strips
upon spools 10~ 11. They take the form of conventional lead support frames
; 10 or they may also consist of lead expanded metal. If desired~ each electrode
strip may have a land extending along its edge. Into these electrode
support frames, a unitary mass is pasted as the active material. This
is advantageous because the finished strip electrodes alternate in
~ polarity from cell to cell during battery operation. Thus~ the electrode
- support frames 2, 3 are transformed into strip eaectrodes 12, 13.
With interposition~ of a separator strip 4, which is highly por-
ous but largely insensitive to pressure, and which is unrolled from spool
14, the electrode strips are then brought together while passing over turn-
- about roller 15, after which they can be folded.
Just before the folding procedure, there will be excized over
predetermined distances those portions 9 from the strip electrodes (12), (13)
and from the separator (4) which after insertion into the block casing would
extend across one of the cell-separating partitions (7) or (8) where they
would be superfluous. Removal of the active mass can be accomplished by
air blast~ by rinsing, or if desired, already during the pasting process by
leaving an appropriate portion of the electrode frame free of pasted mass.
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The same measures!may of course, be taken with respect to
the strip portions which extend across the end walls 8 of the block casing
after insertion, so that here, too, only the support frame 2 of strip
electrode 12 remains to provide the external electrical connections 16, 17
beyond end walls 8.
To complete the storage batteryl~ it then only remains to
close the casing. Surprisingly~ this can be done ~ery simply by welding
on a side wall 18~ by means of the known mirror wehding process. ~ue to
the heating effect~ the synthetic material of the cell separating partition
7 and of the end walls 8 of the casing~ as well as of the mating extensions
19 and 20 in side wall 18, penetrates through the framework of the electrode,
so that a strong and liquid-tight joint results. Before this mirror welding
of a lid is performed, it may be desirable to urge the electrode frame
against the separating partition by means of a ram and, if desired, to also
provide additional heating during that process step in order to achieve a
certain penetration of the electrode frame into the edge of cell separating
partition 7 even before the ultimate mirror welding of the lid. The top of
the block casing, which coincides with the plane of the drawing, is then
provided with the conventional filler and gas escape apertures.
Also paraIlel to the plane of the drawing is the plane of
the electrolyte surface, whereas the closure plane designated by the
phantom lines AA is perpendicular to the electrolyte surface.
The necessary terminal post connections for such a storage
battery may be formed inside or outside the cell from the protruding
electrode frame portion, by pressing on and, if desired, welding on of a
terminal post.
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It is apparent that the conventional manufacturing steps
of curing, forming, preserving (e g. by treatment with boric acid) may be
accomplished outside the block casing. For the continuousness of the
manufacturing process it is particularly desirable that these steps be
performed within the block casing itself, after insertion of the electrode
packages therein.
The advantage of the storage battery which has been described
is that its manufacturing process exhibits a particularly desirable material
flow.
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