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
  • H01M4/66—Selection of materials
  • H01M4/68—Selection of materials for use in lead-acid accumulators
  • H01M4/685—Lead alloys
• • 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

• Lead is used in lead-acid batteries to manufacture the oxide that is used in making the positive and negative active material.
• Lead is also used as the supporting and conducting structures, i.e., the positive and negative grid plates, for the active material. In its pure form, however, lead is too soft for the manufacturing processes entailed in making the plates, and for the subsequent assembly into the final battery product.
• conventional automotive lead-acid batteries employ grids made from an antimony-lead alloy in which the antimony content ranges from about 3 to 42% by weight of the alloy composition. These alloys are capable of being formed at acceptable commercial rates into battery grids by gravity casting techniques. When a lead-antimony alloy is used, however, it causes gassing and subsequent water loss. Moreover, as the percentage of antimony increases, the gassing rate increases.
• a hybrid battery consists of a low antimony lead positive grid alloy (generally about 1.3%- 1.6% antimony), and a calcium lead negative grid alloy. Since the amount of antimony in the negative grid affects gassing, the change to a calcium lead negative grid alloy lowers the gassing rate. It is, however, important to note that during the life of the battery, antimony will transfer from the positive plate to the negative plate, so that some gassing will occur, even though it is much lower than it would be if the negative grid were made of antimony.
• the positive grid alloy was changed to a lead-calcium alloy composition.
• These alloys often include additional elements such as tin and silver.
• various other additives are used to help in grain refining, such as arsenic, sulfur and copper. While batteries with this grid plate configuration still experience gassing, it is at a rate of only approximately 30% to 40% of a lead-antimony alloy battery.
• Various lead-calcium alloys for battery grid plates are disclosed in U.S. Patent Nos. 4,125,690; 2,860,969; 3,287,165; and 5,298,350. Problems remain, however, as further described below.
• the engine compartment area in the typical automobile has also shrunk, thus forcing all of the components closer to the engine.
• close-coupled catalytic converters, EGR valves or other components that create high heat are located adjacent the exhaust manifold, and the intense heat of such converters results in the engine compartment becoming even hotter.
• the Battery Council International (BCI) periodically conducts an analysis of a large number of batteries under warranty.
• BCI Battery Council International
• One such analysis has shown that the areas of the country with the average highest mean temperatures also have the lowest battery life.
• short battery life due to gassing and attendant water loss (which increases positive grid corrosion and growth) is one of the primary failure modes.
• the change to an all lead-calcium battery has extended the life of the battery in these areas of the country by reducing gassing and hence water loss, but further improvements are constantly sought.
• lead-calcium alloy positive grids There are currently two ways to make lead-calcium alloy positive grids. The first is by the use of book mold casting. The other is with an expanded metal process, using both wrought and cast strip. These techniques are entirely different and require two slightly different lead-calcium alloys.
• the grid produced is relatively rigid with full borders along each side, top and bottom. This lends rigidity to the grid and helps prevent vertical grid growth. Since the structure is basically rigid, a lower calcium content (which tends to help hardness) can be used in order to give it strength during the high temperatures the battery will experience. Silver is added to provide strength. The most important part to the alloy, however, is the tin content. At the quantities used in accordance with this invention, the tin provides another measure of strength at temperatures by providing resistance to intergranular corrosion and grid growth over time. The tin also serves to help in recharging batteries from extremely low depths of discharging, particularly those that are due to low current (typically milliamps) draw.
• Expanded metal provides a grid with a top border but with no side frames and no substantial bottom border. Because the grid is expanded, the pattern itself inherently has grid growth problems. In order to overcome this, the alloy needs to be modified vis-a-vis the alloy produced by the book mold process. Specifically, a higher calcium content provides the necessary hardness, while the tin remains substantially the same. The silver content is lowered, however, because its use in higher concentrations would make the grid material too hard. Within the expanded metal processes, both wrought and cast strip may be used, and the alloy in accordance with this invention would remain essentially the same for both types of expanded metal processes.
• the invention relates to a battery grid plate composition comprising by percent weight: Calcium .035 - .085
• the invention relates to a battery grid plate formed by a book mold process consisting essentially of, by percent weight: Calcium .035 - .055
• the invention relates to a battery grid plate formed by an expanded metal process consisting essentially of, by percent weight: Calcium .045 - .085
• FIGURE 1 is a side elevation of a conventional grid plate formed by a book mold process
• FIGURE 2 is a side elevation of a conventional grid plate formed by a metal expansion process.
• a positive grid 10 is illustrated, of the type generally produced by a conventional book mold system.
• the grid 10 is formed with full top, bottom and side border portions 12, 14, 16 and 18, respectively, along with an interior grid 20 formed by mutually perpendicular webs or grid members 22, 24.
• a positive grid 26 is illustrated, and which is of the type formed by a conventional expanded metal process.
• the grid 26 is formed with a top border 28 and a bottom border 30, but there are no discrete side borders.
• the lower or bottom border 30 has a lesser thickness or width than the top border 28.
• the interior grid 32 is formed by a plurality of oppositely oriented, diagonal webs or grid members 34 and 36.
• a positive grid plate for a battery has the following composition by percent weight:
• aluminum in the amount of .005% by weight may be included.
• the positive grid plate formed by the conventional book mold process has the following composition by percent weight: % Calcium .035 - .055
• the positive grid formed by an expanded metal process has the following composition, by percent weight:

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

Priority Applications (5)

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Publications (1)

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Cited By (2)

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Citations (5)

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• 1997
  • 1997-04-18 US US08/839,302 patent/US5834141A/en not_active Expired - Lifetime
• 1998
  • 1998-03-19 WO PCT/US1998/005276 patent/WO1998048468A1/en active IP Right Grant
  • 1998-03-19 PL PL330554A patent/PL190918B1/pl not_active IP Right Cessation
  • 1998-03-19 DE DE69819468T patent/DE69819468T2/de not_active Expired - Lifetime
  • 1998-03-19 EP EP98910471A patent/EP0947015B1/en not_active Expired - Lifetime
  • 1998-03-19 ES ES98910471T patent/ES2212826T3/es not_active Expired - Lifetime
  • 1998-03-19 CA CA002259634A patent/CA2259634C/en not_active Expired - Lifetime
  • 1998-03-19 PT PT98910471T patent/PT947015E/pt unknown
  • 1998-03-19 BR BR9804853A patent/BR9804853A/pt not_active IP Right Cessation

Patent Citations (5)

Non-Patent Citations (3)

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