Battery with side wall ribs

A lead storage battery with a monobloc container receives plate groups in cell compartments which are adjustable in width using a series of side wall ribs. Each rib includes a cell connector formed on the container wall, which is in turn provided with support portions which extend into the container compartment to define a roughly T-shaped cross-section. Each rib is further joined to the bottom of the container along its cross-section. Since the support portions are aligned with, or substantially aligned with the container wall, a large-surface support is provided for receiving a plate group, preventing the potential for wearing into the outermost electrodes of the plate group during vibrational stress, and the failure of the mass which can then result.

BACKGROUND OF THE INVENTION 
The present invention relates to storage batteries, especially lead storage 
batteries, with a plastic monobloc container having vertical walls with 
separating ribs. 
Monobloc containers for lead storage batteries are conventionally produced 
in several sizes (classes), defining a variety of available battery types. 
For any given battery type, the capacity of the battery can be varied 
responsive to need. The need to accommodate different battery types 
requires the use of different injection molds (for each battery type). Due 
to cost considerations, this has led to a situation where only a few types 
(sizes) of batteries are offered. The result has been that only a few 
standardized outside dimensions are available, with widely differing 
capacities for any given container type. This is achieved by varying the 
number of positive and negative plates (i.e., plate groups) within each 
compartment of the container. This leads to corresponding variations in 
the cell space which is left free by the installed plate groups. These 
free spaces are conventionally filled with filler pieces referred to as 
plug-in separators. 
Another expedient for reducing the free spaces in battery containers, to 
establish the volume required for the plate system to be installed, is to 
provide the intermediate and end walls with vertical ribs. The vertical 
ribs serve as spacers, and at the same time stiffen the intermediate walls 
(i.e., the partitions) while ensuring better electrolyte circulation 
around the outermost electrode plates of the installed plate groups. An 
example of such a construction is disclosed, for example, by EP-OS 
169,179. 
It is also known (for example, from DE-OS 3,117,917 or DE-OS 3,128,224) 
that the stiffening ribs arranged on the end walls and partitions of the 
container can be replaced with elastic, spring-like ribs. These ribs are 
directly formed on the container, extending toward the opposing wall at an 
angle which deviates from 90.degree.. The use of such ribs is advantageous 
in that they permit automatic installation of the plate groups, and can be 
molded to the plate system which is employed. However, a shortcoming is 
that such ribs can cause damage to the outermost electrode plates during 
vibrational stresses of the storage battery. This can be remedied by 
packing spacers against the ribs so that the outermost plates of the plate 
groups are covered. However, the use of spacers tends to complicate the 
installation process (with additional components), and makes automation 
more costly. 
SUMMARY OF THE INVENTION 
It is therefore the primary object of the present invention to provide a 
lead storage battery with a monobloc container having ribs on inside walls 
of the container that permit an automated installation of plate groups in 
the compartments of the container. 
It is also an object of the present invention to provide a lead storage 
battery with a monobloc container having ribs on inside walls of the 
container that ensure a suitably rigid positioning of the plate groups, so 
that the outermost plates are in close contact with the ribs. 
It is also an object of the present invention to provide a lead storage 
battery with a monobloc container having ribs on inside walls of the 
container that are configured to avoid damage to the outermost plates when 
the battery is exposed to vibrational stresses. 
These and other objects are achieved in accordance with the present 
invention by providing the storage battery with a series of ribs including 
a cell connecting portion formed on the wall of the container, and support 
portions extending from the terminating edge of the cell connecting 
portion. The support portions preferably project from both sides of the 
cell connecting portion, into the container, so that a substantially 
T-shaped cross-section is produced. The ribs are preferably joined to the 
bottom of the container along their entire cross-section. 
Such ribs are advantageously formed during injection molding of the 
container, particularly since the ribs are preferably "rooted" to the 
bottom of the container. Rooting of the ribs to the bottom of the 
container is important so that the ribs are essentially rigid, at least at 
their lowermost end. Along their uppermost regions, the ribs are in 
contrast joined to the container along the leg of the cell connecting 
portion (forming the base of the "T") so that the ribs become increasingly 
more flexible along their length (i.e., with height). 
Upon assembly, the plate groups are introduced into the compartments of the 
container in a way which is substantially free of friction. Such assembly 
is further facilitated by tapering the overall profile of the uppermost 
portions of the ribs. To this end, the support portions terminate with 
rounded edges, and the cell connecting portion tapers from the rounded 
edges of the support portions to the container wall. 
The support portions of each rib are preferably aligned substantially 
parallel to the container wall. This permits an installation that offers a 
large-surface support for the electrode plates, which is quite 
advantageous in receiving the outermost plates of the plate group. This is 
to be distinguished from prior support ribs, which conventionally employ 
narrow support surfaces or exposed edges capable of wearing into the 
electrode plates during vibrational stresses on the battery (which 
necessarily leads to failures of the mass). In accordance with the present 
invention, the plate groups are rigidly held by the ribs, remaining 
undamaged under similar conditions. 
For further discussion regarding the improvements of the present invention, 
reference is made to the detailed description which is provided below, 
taken in conjunction with the following illustrations.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
FIG. 1a is a top view, and FIG. 1b is a side view (viewed toward the 
container partition), of a container C having side wall ribs S with a 
cross-sectional shape which is T-shaped. Each of the side wall ribs S 
includes a cell connector 1 extending perpendicularly from the container 
wall 3 and into the container. A pair of support portions 2 project from 
the terminating end of each cell connector 1, forming a second arm of the 
T-shaped ribs. The support portions 2 combine to provide a broad support 
surface, due to their parallel alignment with the container wall 3, for 
effectively receiving a plate group (system not shown for purposes of 
clarity) without the potential for damage due to vibrational stresses of 
the battery. 
As is best seen in FIG. 1b, the support portions 2 are preferably rounded 
along the upper ends of the ribs, at 4. This helps to avoid sharp edges 
for contacting the plate groups, making it easier for the plate groups to 
slide into the cell container upon their assembly. The upper ends of the 
cell connectors 1 are formed as sloping elements which recede to the 
container wall 3, to further avoid sharp edges for contacting the plate 
groups as they are installed. 
FIG. 2 shows another advantageous shape for the side wall ribs of the 
present invention. In this configuration, the support portions 2' are 
angled to develop a Y-shaped cross-section. Upon assembly, the plate 
groups are pressed into the cell container, and are frictionally retained 
in position responsive to the spring-like elastic spreading of the 
slightly angled (Y-shaped) support portions 2' (essentially returning the 
support portions 2' to a T-shape). In practice, the angle between the arms 
of the "Y" should not be less than 150.degree.. FIG. 3 also shows a side 
wall rib of the present invention which has a certain degree of 
elasticity. In this case, a folded (accordion-like) cell connector 1' is 
formed on the container wall 3, which can retract as a plate group is 
received within the cell container to achieve a similar end result. 
Irrespective of their embodiment, the side wall ribs of the present 
invention should combine to define a support surface amounting to at least 
40% of the adjoining plate surface, for proper support to result. It has 
been found to be particularly favorable if about 60% or more of the 
adjoining plate surfaces are covered. Such conditions can be maintained by 
adjusting the lengths of the support portions, and the mutual spacings and 
height of the side wall ribs. 
The cell connector (1, 1') of each rib joined to the container should 
preferably have roughly the same width as the support portions (2, 2'). 
However, this width should be no greater than the thickness of the 
container wall (i.e., for battery containers produced from elastic 
plastics, this thickness should amount to no more than 2 to 5 mm and 
especially about 2.5 mm). The longest possible support portions are 
preferred. However, the thickness of the support portions should 
essentially correspond to the thickness of the cell connectors emerging 
from the cell wall. The thickness of the cell connector is also limited by 
the injection molding process, and in certain cases, by the container 
height. Tall containers will generally require thicker cell connectors 
than low profile containers due to smooth material flow and good 
deformability. The thickest possible cell connectors (i.e., a thickness of 
about 5 mm ) are generally prescribed in cases where the ribs are to 
extend fully to the height of the cover. In such case, the ribs can 
additionally serve to support the cover of the battery and to take up 
forces during overhead fastening of the battery. Preferably, the ribs 
extend farther upwardly toward the upper edge of the container along mid 
regions of the wall than along the side (lateral) regions (see FIG. 1b). 
The side wall ribs of the present invention not only make the storage 
battery container robot-compatible with respect to electrode (plate group) 
insertion, but above all permit storage batteries of different capacities 
to be assembled with correspondingly reduced or increased (in size) plate 
systems in monobloc containers having the same overall outer dimensions. 
This is because only the ribs determine the available width, so that both 
thicker and thinner plate systems can be received without special 
adaptations. The ribs function as spacers and thus secure the plate groups 
in a particularly favorable way so that the electrode plates experience no 
damage during vibration stress. Due to both their material-related and 
structure-related residual elasticity, the ribs are also in a position to 
take up tolerances in thickness, such as can occur in plate systems from 
the same manufacturing lot, or different lots, as well as differences in 
fastening capacity (of the ribs). 
It will be understood that various changes in the details, materials and 
arrangement of parts which have been herein described and illustrated in 
order to explain the nature of this invention may be made by those skilled 
in the art within the principle and scope of the invention as expressed in 
the following claims.