US3189484A - Process for the drying of negative electrode plates - Google Patents

Process for the drying of negative electrode plates Download PDF

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Publication number
US3189484A
US3189484A US386118A US38611864A US3189484A US 3189484 A US3189484 A US 3189484A US 386118 A US386118 A US 386118A US 38611864 A US38611864 A US 38611864A US 3189484 A US3189484 A US 3189484A
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electrode
water
bath
drying
plate
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US386118A
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English (en)
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Sundman Folke
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Boliden Batteri AB
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Boliden Batteri AB
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    • 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
    • H01M4/14—Electrodes for lead-acid accumulators
    • H01M4/16—Processes of manufacture
    • H01M4/22—Forming of electrodes
    • 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

  • the present invention pertains to a process for the drying of negative electrode plates for a lead accumulator of the dry-charged type retaining water following the forming process.
  • Such negative electrode plates are usually manufactured by first shaping and pasting a grid with lead oxide and then subjecting the plate thus formed to a special electrolytic reduction process in the presence of an aqueous solution of sulfuric acid, whereby the lead oxide is reduced into a highly active finely divided lead metal in the form of sponge. Following this electrolytic treatment, the electrode plate is washed with water to remove the sulfuric acid retained in the pores of the electrode.
  • the invention is concerned with a process for removing this water by a drying process, in which the electrode plate is maintained immersed in a bath consisting of a treament liquid no more than slightly miscible with water While heating this bath to a sufficiently high temperature to expel the water from the electrode and to substitute treatment liquid therefor and in which this treatment liquid is then evaporated with formation of a protective layer on the electrode plate.
  • the negative electrodes to be dried are suspended in a container, whereupon a treatment liquid consisting of a solution of a diflicultiy volatile substance in kerosene is introduced into the container to form a bath surrounding the electrodes.
  • This bath is then heated to a sufficiently high temperature to expel the Water and substitute treatment liquid therefor.
  • the bath is then removed from the container, whereby, due to the own heat of the electrode, the volatile portion of the treatment liquid evaporates partially.
  • the remaining portion of the kerosene retained by the electrode is then removed by permitting a hot gaseous medium to pass outside the flat sides thereof.
  • the protective layer is distributed in such a way that the concentration of the agent is the same throughout the whole mass of the electrode, and, on the other hand, that in planes in parallel with the fiat sides the concentration of the protective agent is higher in the lower portion of the electrode plate than in the upper portion thereof, the term lower being used to indicate that or those parts of the electrode winch were on the lowest level in the bath treatment and the term upper that or those parts which were on the highest level.
  • the experiments used a solution of parafiin in kerosene as a treatment liquid and so-called double electrodes, the lower part of this electrode being thus that part of the electrode which was immersed most deeply into the bath of treatment liquid.
  • the electrodes obtained according to the known process suffer from the disadvantage that, seen in a direction at right angles to the fiat sides of the electrodes, the concentration of the protective agent is constant throughout the whole active mass, which in turn means that the interior of the plate obtains too an effective protection while the surface particles, which are most exposed to the influence of the atmosphere, obtained a reduced protection.
  • the electrode plate freed from water is maintained immersed in a second bath consisting of a solution of a material capable of forming a protective coating or impregnation on the electrode in a volatile liquid not or no more than slightly miscible with water, whereupon the volatile liquid used as a solvent in the coating or impregnating process is evaporated together with the remaining treatment liquid from the water expelling process.
  • the electrode plate has its protective agent uniformly distributed in planes in parallel with the flat sides of the electrode plate.
  • the water1removing process may preferably be plate in the second bath consisting of a solution of paraffin in kerosene, the upper part of the electrode will receive comparatively more solution. However, after taking up the electrode plate from the bath and most probbe equalized throughout the active mass.
  • a treatment liquid As a treatment liquid is used a liquid the predominating 'part of which boils at a'temperature substantially in excess of 100 C., the boiling point of water, such as gasoline, white turpentine, kerosene, esters, ethers, ketones and the like, the water vaporized being condensed and discharged.
  • a non- 1 combustible treatmentliquid e.g. belonging to the class of chlorinated hydrocarbons such as carbon tetrachlo- Jride, .trichloroethylene or perehlorethylene.
  • the electrode plate has now been freed from its water including the water capillary bound and is then to be provided with the protecting agent.
  • the purpose of this agent is to prevent that the particles of active'mass of the electrode will be attacked by the oxygen and the moisture of the atmosphere'during the period in storage.
  • the impregnating process ' is carried out by dipping.
  • the protective agent is applied in the 'form of a solution.
  • dissolving the protective agent may be used, it, however, being necessary that the solvent is a liquid in which ,Water is no more than slightly soluble. It is proper to In principle any solvent capable use the same solvent for the protective agent as for expelling the water from the formed electrode plate in the first stage.
  • a protective agent for theelectrode should be men a tioned products on the basis of mineral oil such as lubricating oil fractions, parafiin wax, asphalt as well as natural and synthetic vresins and plastics for example polyethylene, water repelling salts etc.
  • the protective agent may a either be a substance liquid at room temperature or preferably a substance solid at the normal'temperature of the atmosphere.
  • protective agents should be mentioned substances having a'melting point in excess of -35 C., for example paraflin wax,
  • Suitable protective agents are paraffin wax, parafl'in oil, castor oil and so-called yolk (also called suint, an
  • the protective coating may also be provided by applying one or more polymerizable substances which are caused to polymerize during the heat treatment necessary for driving off the treatment liquid used for removing the water in the first stage.
  • Preferred amounts of the protective agent present in the impregnating solution applied. to the electrode freed from Water are 10400, preferably 10-30 g. of protective agent, for instance, paraflin wax of the melting point out by dipping the electrode/plate in 'a cold solution (temperature not exceeding 50 C.) of the protective agent for a period of time in the range of from 10 sec. to 10 min.
  • the conditions used for applying the protective agent for the electrode plate may easily be controlled to impart a maximum of protective eifect'to the electrode plate without any essential decrease occurring in respect of the ability, of the electrolyte rapidly to get in an intimate contact with the active mass of the electrode.
  • the electrode plate After the protective agent has been supplied. to the electrode plate the latter issubjected to a drying process to drive off the treatment liquid and the solvent used for the protective agent.
  • This drying of the electrode is most preferably eifected by hot air but also other gaseous V mediums such as carbon dioxide may be used. 7
  • the temperature used for driving off the treatment liquid from the electrode plate depends on 'the boiling point or boiling point interval of the treatment liquid. It kerosene or mineral spirit is used as a treatment'liquid and as a solventfor 'the protective agent suitable temperatures for the driving-off process are in the range of from to 190 C., preferably 'in the range from to C. However, also temperatures below 150 C. may be used in extreme cases. Temperatures above C. may be used in certain cases, if a treatment liquid at least mainly consisting of high boiling components is used for the removalof the water in the first stage.
  • suitable temperatures for the driving-off process are in the range of from to 190 C., preferably 'in the range from to C. However, also temperatures below 150 C. may be used in extreme cases. Temperatures above C. may be used in certain cases, if a treatment liquid at least mainly consisting of high boiling components is used for the removalof the water in the first stage.
  • temperature used for driving off the treatment liquid must not be so high as to cause changes in the structure of the lead. In practice temperatures in excess of 250 C. are not suitable in view of these possible changes.
  • the electrode plate For sanitary purposes it may be preferable to cool the electrode plate in a closed chamber also serving as a sluice before taking it out of the drying apparatus.
  • An apparatus for drying formed negative electrode plates may comprise a first vessel adapted to contain a bath consisting of a treatmentliquid not more than slightly soluble in water, heating means in said vessel to keep the temperature of said bath sufiiciently high to drive off a the water retained by the active mass of the electrode after forming and washing, a second vessel adapted to contain an impregnatingsolution comprising a protecting agent for the electrode, cooling'means in this vessel to keep the temperature of the bath'below 50 C.', a drying 1 chamber provided with heatingmeans for a drying medium passing around the electrodesto drive oil the treatment liquidand the solvent used for the protecting agent;
  • the vessels and drying chamber being connected with each other in series by passages arranged therebetween, means for closing and opening these passages, basket elevators arranged in these vessels, respectively, adapted to contain crates with electrode plates, these crates being supported by rolls attached to these basket elevators, and fixed rolls arranged each in the passage between the two vessels, in the passage between the second vessel and the drying chamber, the fixed rolls and the rolls attached to the basket elevators, respectively, forming a path inclining in a direction from the first vessel to the drying chamber, the arrangement enabling the drying process to be carried out semicontinuously.
  • FIGURE 1 is a view of the bath containers.
  • FIGURE 2 is a view of the drying chamber.
  • the apparatus used for the drying process above referred to thus consists of two vessels or containers, the first of which 1 is adapted to receive a bath consisting of kerosene as a treatment liquid and the second one 2 of which is adapted to receive a bath 11 of an impregnating solution consisting of the same kerosene as a solvent and parafiin wax dissolved therein.
  • a chamber 3 in which the electrodes treated in container 1 and impregnated in container 2 are to be freed from kerosene.
  • a cooling chamber 4 connected, wherein the dried electrodes are to be cooled before being taken out of the drying apparatus.
  • heating elements 5 are arranged to maintain-the temperature of the kerosene bath at a sufficiently high temperature to cause an evaporation of the water present in the electrodes to be treated.
  • a cooling tube 6 is arranged to keep the temperature of the bath at a temperature below 50 C. in the impregnation of the electrode plates freed from water in the container 1.
  • a fan 7 is arranged to conduct a stream of hot air around the electrodes to remove the solvent used for the impregnating process.
  • This air is first passed around heating elements 12 in the bottom of the chamber from an inlet (not shown) and the spent drying air containing the vapors of solvent is passed out from the drying chamber through an outlet duct'at the top of the chamber, to which tube the fan 7 is connected to the shaft of the fan (not shown) in a manner obvious to any one skilled in the art.
  • an elevator basket 8 This basket is adapted to contain a crate 9 with electrodes.
  • This crate is supported by rolls 13 attached to the basket, which latter can be elevated and lowered by actuating a piston adapted to slide in a tube by a pressure medium, such as compressed air or a pressure liquid.
  • a pressure medium such as compressed air or a pressure liquid.
  • this piston causes the basket to move either upwardly or downwardly by actuating two ropes 15 and 16, respectively, supported by suitable fixed break rolls 17.
  • the container 1 is provided with an outlet 18 connected to a cooler (not shown) for the water driven off during the dewatering process.
  • the cooling tube 4 connected to the drying chamber 3 is provided with a swingable gate 25 which is mechanically operated in the manner above referred to with reference to the gate 21.
  • a swingable gate 26 at the end of the cooling tube 4, this gate being arranged to open and close the cooling tube when treated electrodes are to be taken out of the drying apparatus.
  • Special stop means (not shown) are arranged in the containers 1 and 2, respectively, in the drying chamber 3 and in the cooling tube 4 to prevent non-intended movement of the basket 8 during its retention in the different treatment vessels. These stop means are of course to be operated from the outside of the apparatus.
  • the apparatus is preferable insofar as it enables a semicontinuous operation of the drying process.
  • EXAMPLE 1 A number of formed lead electrode plates for a motor car battery, containing water (about 10 ml. per plate) from the washing process following the reduction process to remove sulfuric acid is placed in the crate 9 and dipped in the bath 16 consisting of kerosene, which has been preheated to a temperature of C. The bath is then haeted by the heating elements sufiiciently to expel the water from the electrodes (120-130" C.). The water leaving the electrode and accompanying small amounts of light hydrocarbons from the kerosene are condensed in a cooler, the hydrocarbons being returned to the bath.
  • the electrodes are then taken up from the bath by elevating the basket 8 and then allowed to roll through the tube 20 on the rolls 27 to the elevator basket 1? of container 2.
  • This container holds an impregnating solution consisting of kerosene with paraffin wax dissolved therein in an amount of 36 g. per liter of solution.
  • Th electrodes are immersed in this bath for 5 min. at a temperature of 40 C. after which the electrodes are subjected to a temperature of C. in the drying chamber 3 to drive off the kerosene with which the electrodes have been soaked during the dewatering and impregnating steps. After the kerosene has been removed the plates are allowed to cool in the cooling chamber 4, whereupon they are taken out from the drying apparatus.
  • the electrode plates thus treated was examined on distribution of par-afi'in wax by the method described beneath.
  • the paratfin wax had been uniformly distributed throughout the plate, seen in planes in parallel with the flat sides, but seen in a direction at right angles to the flat sides of the electrode plate, the distribution of protection agent was such that the concen tration was higher at the surface and that in the middle part.
  • EXAMPLE 2 For this purpose a pack of electrodes is treated to removed water in the same way as described in Example 1. The electrodes freed from water retaining kerosene having a temperature of about 120 C. are then impregnated by rapidly dipping them in a kerosene solution of paraflin (30 g. per liter) for 3 min. at a temperature of 26 C. and then subjecting them to hot air at a temperature of 180 C. to remove the kerosene.
  • the electrode plates were examined on distribution on parafiin by the method described beneath. In this connec-tion, it was found that the paraifin, as in Example 1, had been uniformly distributed throughout the plate, seen in planes in parallel with the flat sides of the electrode plate, but seen in a direction at right angles to the flat sides of the plate, which had a thickness of 2 mnr, its distribution was such that theconcentration of paraifin wax was considerably higher at the surface than in the middle part ithereof. The total amount of paraflin; wax in the plate which Weighed'ZOO g. was found to be 50 mg.
  • a method for the drying and coating'of a negative electrode plate for lead accumulators of the dry-chargedtype, which plate contains water following the forming process comprising (1) suspending said plate in a'bath consisting of a treatment liquid which is 'no more than slightly miscible with water, said liquid boiling at a temperature high-. er than the boiling point of water and being substantially free of difficulty volatile material, i V

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Battery Electrode And Active Subsutance (AREA)
US386118A 1960-01-14 1964-07-27 Process for the drying of negative electrode plates Expired - Lifetime US3189484A (en)

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US (1) US3189484A (enrdf_load_html_response)
CH (1) CH411063A (enrdf_load_html_response)
DE (1) DE1192718B (enrdf_load_html_response)
DK (1) DK118678B (enrdf_load_html_response)
ES (1) ES263495A1 (enrdf_load_html_response)
GB (1) GB875974A (enrdf_load_html_response)
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110119951A1 (en) * 2002-12-20 2011-05-26 Bsh Bosch Und Siemens Hausgerate Gmbh Device for determining the conductance of laundry, dryers and method for preventing deposits on electrodes

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2747008A (en) * 1952-05-21 1956-05-22 Tudor Ab Method and means for drying accumulator electrodes
US2889388A (en) * 1955-08-09 1959-06-02 Electric Sterage Battery Compa Production of dry-charged battery plates

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR857312A (fr) * 1939-03-27 1940-09-06 Perfectionnements aux accumulateurs électriques
FR1079374A (fr) * 1952-05-21 1954-11-29 Tudor Ab Procédé et dispositif pour sécher les électrodes des accumulteurs
DE961270C (de) * 1952-06-05 1957-04-04 Bosch Gmbh Robert Elektrischer Sammler, dessen formierte negative Elektroden mit einem Schutzueberzug versehen sind

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2747008A (en) * 1952-05-21 1956-05-22 Tudor Ab Method and means for drying accumulator electrodes
GB754136A (en) * 1954-01-25 1956-08-01 Tudor Ab Improvements in or relating to methods for drying battery electrodes
US2889388A (en) * 1955-08-09 1959-06-02 Electric Sterage Battery Compa Production of dry-charged battery plates

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110119951A1 (en) * 2002-12-20 2011-05-26 Bsh Bosch Und Siemens Hausgerate Gmbh Device for determining the conductance of laundry, dryers and method for preventing deposits on electrodes
US7975400B2 (en) * 2002-12-20 2011-07-12 Bsh Bosch Und Siemens Hausgeraete Gmbh Device for determining the conductance of laundry, dryers and method for preventing deposits on electrodes
US8286369B2 (en) * 2002-12-20 2012-10-16 Bsh Bosch Und Siemens Hausgeraete Gmbh Device for determining the conductance of laundry, dryers and method for preventing deposits on electrodes

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ES263495A1 (es) 1961-05-16
DE1192718B (de) 1965-05-13
GB875974A (en) 1961-08-30
NL251427A (enrdf_load_html_response)
NL128271C (enrdf_load_html_response)
DK118678B (da) 1970-09-21
CH411063A (de) 1966-04-15

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