Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/70—Carriers or collectors characterised by shape or form
  • H01M4/72—Grids
  • H01M4/73—Grids for lead-acid accumulators, e.g. frame plates
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• This invention relates to battery plate grids particularly, but not exclusively, for lead-acid batteries for use in electrically driven vehicles.
• a battery plate grid for a lead-acid battery comprises a generally rectangular framework which encloses a lattice structure defined by a set of parallel strands intersecting a set of parallel ribs to define inter stices for receiving the paste of electro-chemically active material, normally of rectangular or diamond configuration.
• the ribs normally extend at right angles to the strands and are of increased cross-sectional area as compared with the strands .
• Lead-acid battery plate grids are normally cast from lead or a lead alloy but with the conventional construction described above, and particularly vith grids cast from lead/antimony alloys, it ie found that the intersections between the strands and the ribs of positive plates define sites for rapid anodic corrosion which reduces the working life of the grid in deep cycling applications such as those experienced in electrically driven vehicles. This problem results from the fact that the interconnections between the strands and ribs are relatively massive and hence have a high heat capacity.
• An object of the present invention is therefore to overcome or alleviate the above-mentioned disadvantages experienced with conventional battery plate grids.
• the invention resides in a battery plate grid for a lead-acid battery comprising an external framework surrounding a lattice structure defining interstices for receiving electro-chemically active material the lattice stnicture including a plurality of non-intersecting strands, vith each strand extending non-rectilinearly between a pair of opposite frame members of the grid so that longitudinally spaced portions of the strands are alternately located proximate to, and spaced from, an adjacent strand, proximate portions of adjacent strands being physically interconnected by webs of reduced cross-sectional area as compared with said proximate portions.
• the webs are intended merely to provide sufficient support for the strands during production of the grids, introduction of electrochemically active paste into the interstices of the grids, and assembly of the plates into a battery box.
• the webs are not required to contribute to the electrical performance of the grid and, although the webs corrode during formation and charging, this does not impair the electrical properties of the grid since the strands remain connected to the frame members of the grid.
• the webs are of reduced cross-sectional area as compared with the remainder of the strands, they substantially avoid shrinkage porosity and its attendant problems outlined above encountered with the intersections of conventional grids.
• the support imparted to the strands by the webs is found to be sufficient to allow the elimination of the ribs normally employed to assist in supporting the strands of conventional lead-acid battery grids thereby allowing a saving in weight and hence in improved energy density as compared with conventional battery plates.
• the non-rectilinear nature of the strands it is possible, for a given size and weight of grid, to reduce the dimensions of the lattice interstices and hence the amount of active material contained in each interstice. This not only improves the paste-retaining properties of the plate by also ensures better paste utilization and provides the plate with enhanced current collecting properties and hence improved performance.
• each strand extends in serpentine form between said opposite frame members.
• the accompanying drawing is a.plan view of part of a battery plate grid according to one example of the invention.
• the grid includes a generally rectangular, external framework 11 provided on one frame member 12 with an integral, projecting terminal lug 13 through which, in use, external electrical connections can be made to the grid.
• a lattice structure 14 including a plurality of non-intersecting strands 15 which extend in serpentine form in the plane of the framework 11 between a pair of opposite frame members 16, 17 of the grid.
• each strand 15 is of generally sinusoidal form, although it is to be appreciated that as an alternative the strands could be of sawtooth configuration.
• each strand 15 By virtue of its serpentine form, longitudinally spaced portions of each strand 15 are alternately located proximate to, and spaced from, an adjacent strand 15 or, in the case of the uppermost and lowermost strands, an adjacent frame member of the grid. Adjacent strands thereby define the interstices required to receive the electrochemically active material of the grid.
• each web is 2.4mm wide by 0.1mm thick and hence has a cross-sectional area of 0.24mm 2 .
• the webs 18 serve to physically support the strands during manufacture and subsequent handling of the grid without the need for additional strengthening ribs.
• the webs 18 and strands 15 are found to be non-porous when the grid is produced by casting.
• the webs in the positive plates tend to corrode rapidly during formation and charging it is found that this does not impair the electric properties of the grid since the strands 15 remain connected to the frame members 16, 17.
• the grid described above may be cast from conventional lead/antimony alloy in which case it will enable the production of positive plates having improved corrosion resistance as compared vith plates of equal weight having a conventional grid construction.
• the grid may be cast in other materials, for example lead/calcium/aluminium and lead/arsenic/selenium alloys having a greater resistance to anodic corrosion, in which case the grid construction described above will enable lighter grids to to be produced having the same strength as their conventional counterparts. This will in turn improve the energy density of the finished battery plates.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Cell Electrode Carriers And Collectors (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10516539

Family Applications (1)

Country Status (4)

Cited By (1)

Citations (5)

• 1981
  • 1981-10-05 JP JP56503155A patent/JPS57501555A/ja active Pending
  • 1981-10-05 GB GB08215664A patent/GB2100918A/en not_active Withdrawn
  • 1981-10-05 WO PCT/GB1981/000217 patent/WO1982001277A1/en active Application Filing
  • 1981-10-05 DE DE813152388A patent/DE3152388A1/de active Pending

Patent Citations (5)

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