|Title of Invention||
A VENT VALVE FOR A BIPOLAR BATTERY
|Abstract||The present invention relates to a vent valve for a bipolar battery wherein the primary channel is of a predetermined shape and the secondary channel is provided in the frame to provide access for the gases to the valve either along the length or width of the frame; the primary channel is provided completely in one frame and secondary channel has an inclination formed when two adjacent frames are combined to avoid acid pools in vent channel for the gases; the electrolyte filling ports (vacuum point and acid pressurizing point) with spaces provided at the top and bottom of the frame.|
|Full Text||This invention relates to a vent valve for a bipolar battery.
A thin, bipolar, lead-acid battery includes a number of cells, each of which is provided with one-way vent valve for allowing the gases generated inside to vent before the pressure inside the battery exceeds a certain design value.
The bipolar batteries are gaining increasing importance due to their advantages of weight reduction, effective material utilization, low internal resistance and increased life. In particular, they are suitable for automotive applications (starting, lighting and ignition) due to their high rate discharge capabilities. A bipolar battery consists of a number of bipolar plates, two end plates and required number of separators stacked in a particular order. Each bipolar plate has a positive active material pasted on one side and a negative active material pasted on the other side with a common conducting base. The end plates consist of either positive active material or negative active material with a conducting base and a current collector. The active material is supported with the help of either a plastic mesh or an acid resistant metallic mesh.
This invention is about providing an individual vent valve for each and every cell of a bipolar battery in order to utilize the concept of oxygen recombination to generate water within the system. Then it becomes a maintenance free battery.
This invention will now be described with reference to the accompanying drawings which illustrate by way of example and not by way of limitation embodiments of this invention wherein
FIG. 1 is a top view of a single frame showing the two different channels for the valve and also electrolyte filling ports. Two sectional views (S-S and F-F) of the same frame are also shown with a detailed sectional view (C) of valve channels.
FIG. 2 is a top view of the battery with two sectional views; one sectional view along the width (Section E-E) and the other one along the length (A-A) with detailed sectional views (B, C, D, F and G).
FIG. 3 shows the top view of the battery with two sectional views of the frame walls along the length (Section A-A and Section B-B) and the top view of a selected frame 28.
FIG. 4 is a concept drawing to illustrate how the valves can be better accommodated (in the case of single valve battery of the type embodiment
FIG. 5 is a concept drawing to illustrate how the valves can be better accommodated. A top view 5(B), side views 5(A) and 5(C) are shown, (in the case of dual valve battery of the type embodiment 1)
FIG.l depicts the top view of a frame 9 with two sectional views A-A and B-B and a detailed view C. Frame 9 is a rectangular frame with an internal groove on all the four sides of the battery to accommodate either a bipolar plate or an end plate. This frame is exactly same as the one described in VS Patent 4900643. The frame has two ports 1 & 2 to fill electrolyte in the separator. In the above patent these ports are provided on the sides along the length of the frame due to which pressure drop will be more in the channel itsdf. To avoid this problem the two ports are provided one at top and the other at the bottom to eliminate unnecessary pressure drop in these channels. Vacuum is applied at the port 1 and the electrolyte is pressurized at port 2 to fill the separator with electrolyte, The spaces 7 St 8 are provided to ensure a better pressure distribution across the width (absorbent glass matrix / any other suitable separator) at the both ends of the separator. This arrangement is to avoid dead zones at the corners. Here dead zone refers to a zone where separator is inadequately filled with the electrolyte. The separator length is chosen such that two spaces in addition to 7 & 8 at both the ends of the separator are formed for the same objective. Channel 3 is a primary channel (square/ rectangular/ circular), which provides access to the gases to reach the vent valve from the separator through a secondary channel. Basically 4 and 5 are grooves cut in one frame such that when two such frames are placed apart form a complete secondary channel. Channel 3 and grooves 4 & 5 are clearly depicted in the detail sectional view C. The grooves 4 and 5 are cut such that the secondary channel has an inclination upwards as shown in figure 2-detailed sectional view C. The objective of this arrangement is, if any acid that reaches the primary or secondary channel during electrolyte filling stage comes back to the separator, as it is getting less saturated on discharge of the battery. This arrangement avoids the formation of acid
reservoirs/ pools in the primary channels and avoids additional difficulties and leakage of acid. As the gases can access the venting channel at any point along the length of the channel, even if the channel gets blocked at a few locations the valve 6 does not fail. Single/ dual valves can be provided at the two ends of the primary channel as shown in the figure 1, if demanded by the design requirement. Since the valve dimensions are smaller, especially at higher charging currents single valve may not meet the design requirement. Then one can provide dual valve.
FIG 2 depicts the top view of the embodiment 1 with two sectional views; one along the width (section E-E) and the other one along the length (section A-A) with five detailed sectional views (B, C, D, F, & G). Detail C clearly shows the primary channel 3, secondary channel 4 & 5, the valve 6, frame 9, positive electrode 10, negative electrode 11, common base conductor 12, plastic mesh 13, separator 14, positive end plate 15, and top cover plate 17. Detail sectional view B shows the negative end plate 16. Sealing plastic caps IS and terminal 19 are shown in detail G. The valve cover plate 21 and corresponding groove 22 for the gases to escape are shown in detail D. The embodiment 1 describes the arrangement of single/ dual valve provided in parallel to the electrode plane (cell plane) along with two additional ports to fill the electrolyte.
FIG .3 illustrates the embodiment 2 with single/ dual valve provided on the top frame on a perpendicular plane with respect to the cell plane. As demanded by the battery layout in vehicle the cell plane is positioned horizontally. Then valves will be placed vertically. The objective of providing vertical valves is to eliminate the acid entrainmemV leakage and also to maintain the designed operating parameters of the valve (The presence of acid at the interface of rubber valve and plastic stem may affect the compression pressure and operating pressure (opening pressure) of the valve) In figure 3, top view of the embodiment I and two sectional views to describe the current art and the top view of one particular frame 28 are shown. The sectional view clearly depicts how the primary channel 24 is connected to the valves 26a and 26b on the top frame 27 with help of two vertical channels 25a and 25b. In the second embodiment all the frames are to be identified separately as they are different from one other unlike embodiment 1. The same frame that was discussed in embodiment 1 can be used with certain modifications. Hie length of the primary channel is different for every frame. So the grooves are to be provided accordingly on all the frames to meet the channel length requirements. In addition to that
every frame should consists of additional slots such that when all the frames are arranged one above the other, these slots form vertical channels that connects the primary channel to the valve. One such frame 28 is shown in figure 3. In this frame 28b are the slots on one side and 28c are me slots on other side and 28a is the horizontal primary channel. The valves and routing of gases for the alternative cells are provided on the other side as shown in the top view of the embodiment 2 in figure 3.
FIG.4 illustrates the accommodation of valves on the battery. In vertical valve concept (embodiment 2), since the valves are provided along the length, valves can be accommodated with no difficulty. This accommodation problem appears it: the case of embodiment I only. If it is a single valve battery, the alternative valves 29a & 31a can be provided at one end while the intermediate one 30b is provided at the other end as shown in figure 4. If it is a dual valve battery, the channel 32 and both the valves 32a, 32b of a cell are provided on one side and the same components for the next cell are provided on the other side which was shown by hidden line in the figure 5 A and the figure 5 B is the top view of the same of the figure 5 Au
The terms and expressions herein are of description and not of limitation, having regard to the scope and ambit of this invention.
1. A vent valve for a bipolar battery wherein the primary channel is of a
predetermined shape and the secondary channel is provided in the frame to
provide access for the gases to the valve either along the length or width of
the frame; the primary channel is provided completely in one
frame and secondary channel has an inclination formed when two adjacent frames are combined to avoid acid pools in vent channel for the gases; the electrolyte filling ports (vacuum point and acid pressurizing point) with spaces provided at the top and bottom of the frame.
2. A vent valve as claimed in Claim 1 wherein single/dual valves are
provided at single/ both ends of the primary channel.
3. A vent valve as claimed in Claim 1 wherein valves are provided on the
top frame at the end of the vertical channel connecting the primary channel
with the said valve; slots that are made in all the frames to form vertical
4. A vent valve as claimed in Claim I wherein alternative valves are
provided at one end and the remaining at the other end.
5.A vent valve as claimed in Claim 1 wherein single/ dual valves are provided on the top frame to the single/ pair of vertical channels coming from a particular primary channel, the valves being either provided on one side or the other side.
6 .A vent valve as claimed in Claim I wherein the valves and the channels for alternative cells are provided at one side while the remaining are on the other side.
|Indian Patent Application Number||851/CHE/2007|
|PG Journal Number||08/2011|
|Date of Filing||20-Apr-2007|
|Name of Patentee||TVS MOTOR COMPANY LIMITED|
|Applicant Address||JAYALAKSHMI ESTATES NO.24 (OLD NO.8) HADDOWS ROAD, CHENNAI 600 006|
|PCT International Classification Number||H01M2/00|
|PCT International Application Number||N/A|
|PCT International Filing date|