CA1070376A - Circulating electrolyte battery system - Google Patents
Circulating electrolyte battery systemInfo
- Publication number
- CA1070376A CA1070376A CA270,862A CA270862A CA1070376A CA 1070376 A CA1070376 A CA 1070376A CA 270862 A CA270862 A CA 270862A CA 1070376 A CA1070376 A CA 1070376A
- Authority
- CA
- Canada
- Prior art keywords
- cell
- electrolyte
- stack
- battery
- plates
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4214—Arrangements for moving electrodes or electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/24—Alkaline accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/70—Arrangements for stirring or circulating the electrolyte
- H01M50/77—Arrangements for stirring or circulating the electrolyte with external circulating path
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/61—Types of temperature control
- H01M10/613—Cooling or keeping cold
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/654—Means for temperature control structurally associated with the cells located inside the innermost case of the cells, e.g. mandrels, electrodes or electrolytes
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Secondary Cells (AREA)
- Hybrid Cells (AREA)
- Filling, Topping-Up Batteries (AREA)
Abstract
CIRCULATING ELECTROLYTE BATTERY SYSTEM
ABSTRACT OF THE DISCLOSURE
A circulating electrolyte battery is made, com-prising: at least one cell containing a stack-up of elec-trode plates; an electrolyte cooling means containing elec-trolyte spaced from said cell; electrolyte pumping means connected to said cooling means; and electrolyte circulation means connected from the pumping means to the cell and from the cell to the cooling means; wherein the sides of the cell electrode stack-up are sealed, and at least one electrode plate per stack-up has at least one channel in its surface, the channel constituting from about 0.5% to 10% of the electrode plate surface area, and wherein pumped circulating electrolyte flows only through the channels in the stack-up rather than around the stack-up.
ABSTRACT OF THE DISCLOSURE
A circulating electrolyte battery is made, com-prising: at least one cell containing a stack-up of elec-trode plates; an electrolyte cooling means containing elec-trolyte spaced from said cell; electrolyte pumping means connected to said cooling means; and electrolyte circulation means connected from the pumping means to the cell and from the cell to the cooling means; wherein the sides of the cell electrode stack-up are sealed, and at least one electrode plate per stack-up has at least one channel in its surface, the channel constituting from about 0.5% to 10% of the electrode plate surface area, and wherein pumped circulating electrolyte flows only through the channels in the stack-up rather than around the stack-up.
Description
BACKGROUND OF THE INVENTION
Secondary electric storage cells, operating at hlgh rates of charge and discharge, require some method of cooling to prevent overheating. This is especially true for electrlc vehlcle applicatlons, where a large number of ln-20 terconnected cells and a tlght packaglng arrangement may be required. One solution is to clrculate electrolyte as a heat exchange medlum through a cell and lnto a coollng reservolr, and then to reclrculate the electrolyte back into the cellO
Imschenetzky recognized this solutlon in UOS.
Patent 400,215, where an electrolyte supply plpe was arranged at the bottom of a galvanic batteryO Thls forced fresh *
electrolyte up and around the electrodes in each cell stack--1- 13~
. ,: , , ~ , . , , : .
~, . . .: ~ . :~ . . . . .. . .
46,215 ~070376 up. Recently, Chiku, in U S. Patent 3,666,561, taught a zinc-air battery, with clrculation of electrolyte through a series of electric battery cellsO The circulation was ~-accomplished by pumping electrolyte into the bottom of each cellO Electrolyte, from an electrolyte chamber, flows up through each cell and is removed from the top of each cell through outlet pipesO The electrode stack-up is not sealed against the container, so that electrolyte may flow around one of the three plates of each cell, and oxygen gas is :-introduced into the electrolyte circulation system to reduce lnternal battery current~ ~
Necessarlly, a circulating electrolyte cooling ~-system for a battery is complicated, and to date not all of the problems associated with such systems have been solved.
Nearly all secondary electric storage cell cases are com-posed of metal, glass, rubber, or plastlc boxesO ~ell stack-ups are inserted into the boxes and then a cover is .
attachedO When it is desired to circulate electrolyte through the cell stack-up for cooling purposes, standard case and electrode stack-up construction has not proved satisfactory Associated wlth circulating electrolyte systems are the problems of: coollng every cell on charge and/or .
discharge to permit high current rates to be used; hermetic Joints between terminals, inlet and outlet tubes and case walls; encapsulation and sealing o~ cell stack-ups, so that ~ -electrolyte will be forced to go through them when going ~ :~
from an inlet to an outlet in the case; electrolyte level maintenance; electrolyte specific gravity control and uni- : -- 30 formity; collection and elimination of explosive hydrogen ~. .
Secondary electric storage cells, operating at hlgh rates of charge and discharge, require some method of cooling to prevent overheating. This is especially true for electrlc vehlcle applicatlons, where a large number of ln-20 terconnected cells and a tlght packaglng arrangement may be required. One solution is to clrculate electrolyte as a heat exchange medlum through a cell and lnto a coollng reservolr, and then to reclrculate the electrolyte back into the cellO
Imschenetzky recognized this solutlon in UOS.
Patent 400,215, where an electrolyte supply plpe was arranged at the bottom of a galvanic batteryO Thls forced fresh *
electrolyte up and around the electrodes in each cell stack--1- 13~
. ,: , , ~ , . , , : .
~, . . .: ~ . :~ . . . . .. . .
46,215 ~070376 up. Recently, Chiku, in U S. Patent 3,666,561, taught a zinc-air battery, with clrculation of electrolyte through a series of electric battery cellsO The circulation was ~-accomplished by pumping electrolyte into the bottom of each cellO Electrolyte, from an electrolyte chamber, flows up through each cell and is removed from the top of each cell through outlet pipesO The electrode stack-up is not sealed against the container, so that electrolyte may flow around one of the three plates of each cell, and oxygen gas is :-introduced into the electrolyte circulation system to reduce lnternal battery current~ ~
Necessarlly, a circulating electrolyte cooling ~-system for a battery is complicated, and to date not all of the problems associated with such systems have been solved.
Nearly all secondary electric storage cell cases are com-posed of metal, glass, rubber, or plastlc boxesO ~ell stack-ups are inserted into the boxes and then a cover is .
attachedO When it is desired to circulate electrolyte through the cell stack-up for cooling purposes, standard case and electrode stack-up construction has not proved satisfactory Associated wlth circulating electrolyte systems are the problems of: coollng every cell on charge and/or .
discharge to permit high current rates to be used; hermetic Joints between terminals, inlet and outlet tubes and case walls; encapsulation and sealing o~ cell stack-ups, so that ~ -electrolyte will be forced to go through them when going ~ :~
from an inlet to an outlet in the case; electrolyte level maintenance; electrolyte specific gravity control and uni- : -- 30 formity; collection and elimination of explosive hydrogen ~. .
-2-46,215 , ~ .
1070376 ~ ~
and oxygen gases at one location, where proper safety pre-cautions can be taken; and maki~g the system simpler, so that cell size changes can be readlly and inexpenslvely accomplished O
To solve all o~ these problems the battery has to have the following ~eatures: leakproof, since electrolyte ls circulating under pressure, all the cell cases and plumblng connections must be of the highest order of hermeticity; low pressure drop, to keep the size of the circulation pump small and for leakage and safety reasons; hi~h resistance in the- electrolyte connections between cells, to minlmize self-discharge; unlform pressure drop among all cells, to allow the cells to be connected in parallel arrangement and stlll achieve uniform flow through each cell; and most lmportantly, uniform flow throughout the cell cross-sectlon, so that all plates receive adequate electrolyte flow and assurance that electrolyte flows through the stack-up of a cell, not around them, so that the most effectlve coollng durlng charglng ls achlevedO
SUMMARY OF THE INVENTION
The battery herein descrlbed solves all of the listed problems and has the requlred features descrlbed above. Electrolyte ls circulated through the battery and a reservoir contalning a coollng mechanism by means of a pump.
Any heat exchanglng means, such as cooling water clrculated through colls ln the reservo~r, can be used to cool the electrolyte~ Electrolyte ls clrculated at rates adequate to remove the heat generated by varlous charge, dlscharge rates. The reservoir and pump are attached to the battery with quick disconnect couplings so the battery may be dls-46,215 :, . . .
~070376 -~ -~ .
charge~ wlth or without them~ Electrolyte le~el and specific ~ ; ., ~ ..
gravity are maintained by adding water to the reservoir to maintain a constant height levelO The battery system is vented to the atmosphere at the reservoir through a barrier venting means, which allows explosive hydro~en and oxygen to escape. All of the listed necessary features for this improved circulating electrolyte battéry are accomplished by the foll-owing means:
a) The cell electrodes of each stack-up are sealed and encapsulated in a molded case3 preferably by means of an epoxy resin sealant filler, whlch adheres to the case wall~, terminals, and electrolyte inlet and exhaust tubes, ;
providlng an effective hermetic seal ln all of these loca-tionsO : ";
b) Low and uniform cell to cell pressure drops, and uniform flow of electrolyte through the cell stack-ups is accomplished by providlng channels in the plates, as by cuttlng or pressing narrow slits in themO The channels are spaced apart for effective cooling and constitute no more than 10% of the plate surface area.
c) Electrolyte ls forced to flow through these channels, and not around the perlphery of the cell stack-ups, by the tight fit between the stack faces and the wide ;
front case walls, and by filling the space between the stack-up edges and the narrow edge case walls with a suit-able sealant filler. The filler can be any number of materials, such as a liquid, curable, plastic resin or rubber, foam in place materials, already foamed material cut to fit, etc.
~30 d) High electrical resistance in the electrolyte 46,215 :' '.
-:
~o70376 , plumbing network is accomplished by the use of long inlet and exhaust tubes. The inlet tube preferably extends from the top to the bottom of the cell, while the exhaust tube is preferably formed in a coil at the top of the cellO The manifolds connecting cells with each other are preferably above the cells, which allows electrolyte to drain back into the cells when circulation StopsD This latter feature re-duces the electrical path between cells to the conductivity of the electrolyte film which clings to the piping wallsO
.
Fl~w of electrolyte through the system can be summarlzed as follows: Reservoir; Pump; Battery manifold Cell inlet manifolds; Cell electrolyte lnlet tubes; Cell reservoirs; Through channels in sealed cell stack-ups; Cell :
electrolyte outlet tubes; Cell exhaust manifold; Battery manifold, and the~ on to the Reservolr for coollng.
This lmproved, cell stack-up electrolyte flow system offers many advantages and benefits over other con-ventlonal systems, some of which are:
a) Effective cooling of the stack-up enables higher charge rates to be employed, thus reducing charge tlmeO A typical cycle of charging/discharging, at the C/2 rate, malntains the temperature at between 30C and 35C
wlth circulationO Without circulation, temperatures would exceed 70C, which severely hampers battery life.
b) The hermeticlty of the system elimlnates many safety hazards such as spllls and mists which lead to short circuit grounding paths and potential failures.
c) The parallel flow arrangement, with associated plumbing, insures each cell of proper malntenance, and ell-~30 minates failures due to over or under filling and improper 46,215 - . .
10~70376 ~ ~
speclflc gravity~ ~ ~
.. .
d) The plumbing also prov-~des for safe gas handling ;~
and lends itself well for elimination of hydrogen and oxygen formed during charg~ng. :
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understandlng of the invention, reference may be made to the preferred embodiment, exemplary of the lnventlon, shown in the accompanying drawings, in whlch:
Flgure 1 ls a three dimensional vlew of a circu-latlng electrolyte battery module containlng flve series :
connected battery cells;
Flgure 2 ls a top view, partlally in sectlon, of the battery module of Figure l; i Figure 3 is a side view, partially in section, of the battery module of Figure 2, along the line III;
Figure 4 is a cross-section of the battery module of Figure 2, along llne IV, showlng an electrode plate, having spaced apart channels, sealed into the container, :.:
20 cell inlet manifold, cell electrolyte inlet tube, cell ~ !:
reservolr, and the cell electrolyte outlet tube;
Figure 5 is a cross-section of the plate stack-up of one embodiment of a cell, showlng the sealed electrode plate sldes and edge~, and the channels ln the plate stack-up prov~ding uniform fIow of electrolyte through the stack-up rather than around the periphery of the stack-up; and Figure 6 is a schematlc vlew of an assembly of battery modules fed by a circulatlng electrolyte system, with associated electrolyte cooling reservoir and pump.
. ...... .. . . . . . - . -~ . .. . .. .
46,215 107(~376 DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Figure 1 of the drawings, a battery module 10 is shown with associated dimensions, which ~ -may vary greatly depending on battery use. The battery ~
module, containing at least one cell, can comprise case 11, :
whlch may be, for example, a metal, rubber or plastic box.
Each cell 12 is in its own case or conta~ner havlng flat ~ront and edge wallsO The battery module case 11 is optional, `
however, as the separate cells may be held together solely by the cell exhaust manifold 13 and cell inlet manifold 14, shown disposed in a parallel arrangementO The cells may also be held together by electrical connections between the terminal studs 150 Of course, any other holding or clamping means can be used to hold the separate cells together, such as a bottom U plate, shown as 17 in the drawing, which would be used without the battery module caseO
Figure 2 shows a top view of the battery module with terminal studs 150 Also shown is the coiled cell electrolyte outlet tube 21, which attaches to the cell exhaust manifold 13 at opening 22. The cell electrolyte lnlet tube is shown as 230 Figure 3 also shows the position o~ these tubes within a cell, where the bottom of the cell electrolyte inlet tube ls shown as 300 Flgure 4 shows a cross-section of a preferred cell 12 of thls inventionO Cell electrolyte circulation means, tubular cell inlet manifold 14 and cell exhaust manlfold 13, are preferably disposed in a parallel arrangementO These electrolyte circulation means are preferably connected above the cells to allow electrolyte to drain back into the cells when clrculation stops~ This reduces the electrical path 46,215 ~
.
~, ,.
between cells when electrolyte is not circulating, to the -:
conductivity of the electrolyte film which clings to the manifold tube wallsO
The inlet and outlet manifold tubes will have a ~.
relatively large internal cross-sectionO This provldes low ,..
fluid flow resistance and minimum pressure drop across the cell, which ls requlred to minimize the pressure necessary ~:
for adequate electrolyte flowO The cell inlet and outlet manifold tubes have a long length for hig~ electrical re- .
10 sistance when filled with electrolyteg which is required to -`
minimize current leakage from cell to cellO
Preferably, electrolyte is pumped up through the electrode stack-up, so that hydrogen and oxygen gases gene-rated during charglng are easily exhausted to the cooling reservoir without dangerous pressure build-up In the cell .
of Figure 4, electrolyte, from the manifold 14, flows from . .
the top of the cell case to the bottom of the cell stack-up, ~.
by means of the cell electrolyte inlet tube 23. Cell elec- ~. :
trolyte inlet tube 23 extends from the top of the electrode :
stack-up down along one edge of the battery cell between the edge side of the stack-up and the edge wall of the cell -caseO Then, the tube bends around the bottom Or the stack-up and extends lnto the bottom cell reservoir 40 The cell stack-up, comprising a series of alternate positive and negatlve electrode plates, one of which is shown as 41, may rest on plastic, rubber or foam blocks 42 to form the bottom reservoir 40O
Thus, electrolyte flowing into the cell case will fill up the bottom electrolyte reservoir formed by the blocks or other suitable stack-up supporting means. The 46,215 1~70376 electrolyte will then be forced up the channels 43 in the -electrode platesO
Referring now to Figure 5, a top cross-section view of electrode plate 41, and other alternating positive and negative plates maklng up one type of cell electrode stack-up 50 is shownO The channels 43 can be formed by cutting narrow slits in the electrode plates, by coining the plates to form narrow channels in the plates, or by any other suitable meansO
The cross-section of the channel can be clrcular as shown, square, or any other configurationO The channels can be on both sides of each plate lf desiredO The channels need not be on both positive and negative plates as shown, but may, for example, be pressed only into the positive or negative plates, so that channels would appear on alternate platesO
The channel should not extend through the electrode plate becau~e thls would substantlally reduce the conduc-tivity of the plateO The channel area can comprise from about 0O5% to 10% of the plate face area. If the channels constitute over 10% of the plate area, excessive active material is lost with a reduction in battery performance.
Usually 1 to 6 channels per plate are adequate for good electrolyte circulation and battery coolingO
Channels on one side of the plate, as shown in F~gure 5, are pre~erred, since this provides a strong elec-trode structure requiring minimal machining or pressingO
Not shown are plate separators, which may be made of a con-tlnuous or perforated film of cellulose, polypropylene, nylon or other suitable insulating material between or _g_ . 46,215 " .,. , , ,~ .
1070376 ~; ~
wrapped in serpenti~e ~ashion around each plate~ ~he se- :~
parators of course should be compattble wlth the electro- .::~
lyteO For adequate cooling it i~ essential that electrolyte flows only along the channels between the electro~e plates -~
in the stack-up, and not around the sides and edges of the stack-up, although there may be minimal electrolyte seepage through the platesO :
To provide a hermetic seal and to assure that no electrolyte flows around the stack-up, the spaces 44 between the edge s~de of the stack-up 45 and the edge wall of the cell case 46, shown in Flgures 4 and 5, are filled with a suitable sealantO The se~lant can be a curable 9 llquid, epoxy resin, or any other plastic resln, rubber or other materlal, such as polypropylene foam or polyethylene foam, effective to hermetically seal the space 44 yet not be chemlcally degraded by the electrolyte Thls sealant ~lller will seal and encapsulate the side edge o~ the stack-up and the middle portlon of the electrolyte lnlet tubeO Preferably the sealant wlll be ;.
curable at about 25C~ Prevention of electrolyte flow between the wide face slde of the cell stack-up and the flat, front cell case walls can be accompllshed by a tlght ~lt and intimate contact between the two, as shown in Flgure 5 at 510 This arrangement seals the sides of the electrode stack-ups, i~e the edge sldes and the wlde face sides but not the top and bottom of the stack-upO
The electrode plates making up the stack-ups in the cells are9 preferably~ flexible, porous plaques of about 75% to 95% porosity, made from dlf~usion bonded meta-l flbers, such as nickel flbers, but preferably steel wool or nlckel --10~
~ 46,215 , , 1~70376 coated steel wool, as descrlbed in UO~O Patent 3,895,~600 ~ ~ :
Other type plates, such as porous slntered nickel powder or cast porous nlckel can be used, but have not been found as effective as the expanslble fiber metal platesO The fiber ~:
metal plates can expand and contract during "formation", to provide superior active material loadingc These plaques contaln active battery materlal distributed upon and disposed within the ~ore volume of the plaqueO When, for example, an iron-nickel cell is to be -:
10 made, the actlve material of the positive electrode plates . ~
may comprise Nl(OH)2, with small effective amounts o~ Co(OH)2 .
actlvating addltlveO The negative electrode plates may comprise an iron oxide, such as FeO, Fe203, Fe304, Fe203 H20 or their mixtures, with small effective amounts of sulfur contalnlng actlvating additives fused thereon or mixed therewith, as described in UOSo Patent 3,853,624. Of course other types of posltive and negative active materials and other additlves can be used~
Each electrode plaque has an electrical lead tab :
spot welded or otherwise attached, generally to a colned top areaO These lead tabs 47 provide means for making electrlcal connectlons to the plates. Termlnal connection lugs 48 are attached to the lead tabs to electrically connect the posi-tive and negative plates to the terminal studs 150 Once the electrolyte flows up through the channels 43 of the stack up, in the preferred embodiment of this invention, it exits from the cell through the cell electro-lyte outlet tube 21 and cell exhaust manlfold 130 The length of the cell electrolyte outlet tube 21 can preferably be increased, to provide high electrical resistance in the 46~215 ,.:
electrolyte plumbing network., by making it in a coiled or ~:
similar configuration to that shown in Figures 2 and 4O
In all cases9 the plumbing in the cell and battery module, such as inlet a.nd outlet tubes and manifolds should be made of a non-conduct~ng tubular material such as poly~ ~ :
propylene, polyethylene, polyvinyl chloride, acrylonitrile .-~
butadiene styrene, nylon or other type plastic or rubber .:.
materlals not degradable by the elect~olyteO These non~
conducting tubes and mani~olds can be attached by a suitable adhesive such as epoxy or polyvinyl chloride adhesiveO
To insure electrolyte exit through the electrolyte exhaust tube 21, the space 49 between the top of the cell case and the top of the exhaust tube entrance may be filled with a suitable sealant similar to that described herein-above~ This would also provide a top for the cell caseO In order to provide such a top, a barrier can be placed over the top of the bottom opening of the cell electrolyte outlet tube, and sealant in~ected or poured on top of the barrier to encapsulate the top of the outlet tube, the top of the ~ .
lnlet tube and the terminalsO
Referring now to Figure 6; a battery is built by conneeting cell inlet manifolds 14 and outlet manifolds 13 preferably in parallelO To facilitate constructing a hlgh power battery, several sets of cells, iOeO sets of battery modules 10, are fa~tened in place with all the fluld flow ln parallel to minlmize the pressure required for the syætem and to provide uniform cell to cell coollngO The battery modules can then be positioned to build a complete high power battery ~ystem for the voltage and space requirements of each individual application Figure 6 shows a high power ` 46,215 battery consisting of three banks of three battery modules.
Each battery module contains five cells.
The modules are connected by common battery mani- ;
fold electrolyte circulation means 60, the length and posi-tion of which are dependent on the battery layoutO The battery manifolds can be detached from the heat exchanger means 61 and the electrolyte pumping means 62 by quick dlsconnect couplings 63, so that the high power battery can -be discharged wlthout the heat exchanger and pumpO The heat exchanger or cooling means can comprise an electrolyte cooling reservoir 64 contaln ng cold water cooling coils 65.
A radiator or other cooling apparatus could be added to the system for air cooling to replace or supplement the cooling colls. Electrolyte will be circulated by the pump at rates effective to remove the heat generated by the various charge, discharge ratesO
Electrolyte level and specific gravity are con-trolled by adding water to the electrolyte cooling reservoir 64 through inlet 66, to maintain a constant height level in the cellsO The battery system is vented to the atmosphere, preferably at the reservoir, by any suitable means, such as, for example, a barrler venting means 67, which can be a slntered ceramic barrler, whlch allows hydrogen and oxygen to escape whlle acting as a flame and explosion barrler A
bubble tube extending from the openlng in the reservoir lnto the bottom of an open container of water can also be used to allow gas to escapeO The alkaline electrolyte generally used will be a 10 wto% to 35 wt.% KOH or NaOH aqueous solu-tion wlth preferably about 2 to 20 grams/liter of Li(OH)2.
No gase~ are added to the electrolyte.
4 6 ~ 2 15 ~070376 -`~
" '' ~, Example 1 An iron-nickel hlgh power battery system sililar ~ -to that shoNn in Figures 1 through 6 was constructedO The battery plates were made .~rom nickel plated steel fibers :,.
~ormed into plaquesO Fibers approximately 0 001 x 00 002 x 0025 inch long were used in the flexible, expansible, fiber metal plaquesO They were then heated, in a protective : ~ :
,., environment, causing metal to metal diffusion bonds to form at fiber contact pointsO There was no melting of fibers so 10 as to assure maximum pore volumeO ~ '`~"`
The "nickel" plaques were then colned to about 8 percent- o~ theoretlcal densityg 92 percent porous, and the "iron" plaque bodie~ were coined to 17 percent of theoretical ~ ~.
density, 83 percent porousO Each nickel plaque had two vertical 1/8" wide pressed channelsO The plaque was about 6.5" wide and ~bout 0O09ll thicko The channels were about 0O08ll deepO The channels comprised about 4% of the plaque surface areaO A steel sheet was then spot welded onto the top coined port.ion of the plaques to form electrical lead 20 tab connections, shown as 47 in Figure 4O ' :
The tron active material comprised sulfurized :~
magnetlc iron oxlde particlesO The magnetic iron oxide, had a compo~ition of about 79 percent Fe2O3, 22 percent FeO and 1 percent impuritiesO Enough sulfur was used to provide a ratio o~ sulfur to iron oxide of about Oo l to 10 percent of the sulfurized iron oxideO This additive helped keep the iron active material surface in the active state The "iron" plaques were loaded with the sulfurized .
magnetic iron oxide by a wet pasting techniqueO These iron .
electrode plates were then sized and driedO They contained ~ 46,215 ~ 07037~ `
about 1.5 to about 1.9 grams/cm3 plaque volume of sulfurized iron active material.
The nickel active material comprised nickel h~-droxide doped with a small amount of cobalt h~droxide. The nickel plaques were loaded b~ an impregnation "formation"
impregnation technique. The~ contained about 0.9 to about 1.3 grams/cm3 of active material. The "iron" and "nickel"
plates were then read~ for the cell stack-up operation.
A batter~ module having dimensions about 7" wide x 10" deep x 10" high, as shown in Figure 1 was used and consisted of five cells. The cell cases, made of high density pol~eth~lene and having an open top, were about 7"
wide x 2" deep x 10" high. The~ would contain the electrode stack-ups.
In the stack-up operation, iron and nickel plates were alternatel~ stacked, insulated from each other with a sexpentine wound polyprop~lene separator, and then the terminal connection lugs, shown as 48 in Figure 4, were iner~ gas welded to the tabs to pro~ide means for making electrical connections to the plates. The cell stack-up, along with a 3/16" inside diameter pol~prop~lene cell elec-trolyte inlet tube, was then inserted into the cell case on top of two pol~eth~lene foam blocks, about 1' wide x 2"
deep x 5/8" high, shown as 42 in Figure 4.
The inlet tube ran down the edge side of the stack-up and next to the narrow edge wall of the cell con-tainer, curving at the bottom to run underneath the cell stack-up. The inlet tube stopped at about the middle of the bottom reservoir, shown as 40 in Figure 4, formed b~ the cell stack-up and foam blocks 42. A groove had been formed 46,215 1~7C~376 ln the foam block whlch the inlet tube ran through so that the inle~ tube would fit around the bottom of the stack~up This provided cells having Lnserted electrode stack-ups supported on the bottom with foam blocks9 having an electrolyte inlet tube running into a reservoir at the bottom of the cellO The space, shown as 44 in Figure 4, be-tween edge sides of the stack-up and the 2" edge walls of the cell contai.ners was unfilledO ~ -A viscous9 room temperature curable epoxy resin was then dispensed, ~rom an in~ection gun, ~nto thls space 44 between each edge side of the stack-ups and each edge wall of the cell case, to act as a hermetic sealant and to encapsulate the stack-up between the foam blocks and the top of the electrode stack-upO The top and bottom of the stack-up remained unsealedO This would force the pumped electro-lyte, from the bottom reservoir, to run through the plate channels 43 to the top of the cell rather than around the plates.
The top of the cell was fitted with a 5/16" inside diameter polypropylene cell electrolyte outlet tubeO This tube, shown as 21 in the drawlngs, is ln a coiled conflgur-ation. It starts Just above the electrode stack-ups, under the cell exhaust manifold and runs across the cell width, coiling around the cell electrolyte lnlet tube, running back across the cell, and fitting into the cell exhaust manifold, as shown in Figures 2, 3 and 4O
In order to ~orm a top on the cell, the cell .
electrolyte outlet tube was held in place, with the outlet opening Just at the top of the cell stack-up, with polyvinyl .. ;
chloride adheslve tapeO The tape had holes for the Dottom ~- 46,215 -,~
portion of the electrolyte outlet tube, the positive and negative interconnection lugs and the top of the electrolyte inlet tube to fit throughO A top reservoir volume was thus formed bekween the tape and the top of the stack-upsO
A vigcous, room temperature curable epoxy resin was then dispensed, from an in~ection gun, on top of the .
tape to encapsulate the top portion of the cell electrolyte outlet and inlet tubes and the intercell connection lugs. `
Thus epoxy resin formed the top of the cellO
The iron plaque in the stack-up was still in un-formed conditionO An electrolyte solution containing 25 wt.% KOH and 15 grams/liter of Li(OH)2 was po~red lnto the cell and "formation" of the iron plaques was accomplsihed by a series of charge-discharge cyclesO ~
Cells were then matched and electrically connected ~-to form a five cell battery moduleO Four modules were placed in series and 1/2" inside diameter polyvinyl chloride cell inlet manlfolds and 3/4" inside diameter cell exhaust manlfolds were connected to the cell electrolyte inlet tubes and cell electrolyte outlet tubes respectively with room temper~ture curable epoxy resin glueO Each module was slmilar to that shown in Figure 1, ~ith the manifolds 13 and 14 in parallel on top of the cellsO The modules were assem- ~
bled as shown in Figure 6, only there were four banks of - ::
modules, each bank contain four connected battery modules, each module containing five cellsO Thusg there were a total of 16 modules or 80 cells to form the high power batteryO
Referring to Figure 6, the cell inlet manifolds 14 and exhaust manifolds 13 were connected to common 1" inside diameter polyvinyl chloride battery manifolds with flexible -17- :, : - .
~ 46,215 :::
.,,i polyvinyl chlorlde hose and hose clamps The pump manifolds were connected to a 1/4 HoPo pump and a 25 gallon electro-lyte reservolr 61 made of polyvinyl chlorideO
The reser~oir had a closed top and a cer~mic flame : ~
arrestor barrier vent 66, to exhaust hydrogen or oxygen ~ ~ `
present in the electrolyte due to charglng, and an inlet 67 for adding water or electrolyteO The cooling coils 65 were made: from 20' of coiled 1/2" lnside diameter stainless steelO Cold water was circulated through the colls to cool 10 the circulating electrolyteO `~.
The electrolyte solutton used. in the system con~
tained 25 wt % KOH and 15 grams/liter of Li(OH)2o No gases were added to the electrolyteO The pump and reservoir were connected to the battery modules through dlsconnect valves in the common pump manlfolds so that the high power battery -could be discharged without themO
The assembled hlgh power battery was then bench :~
tested through several 3 hour charge9 2 hour discharge test cycles to establish a capacity ratingO Best results yielded about 17 KWH, or 20 Wh/pounds of cellO The battery was then operated in several electrical vehicles in excess of 100 cycles O
The 80 cell (96 volt) circulatlng electrolyte battery was charged uslng a C/2 (100 AmpO ) charge rate for 3 hoursO Total electrolyte flow was 9 galO per m~nO, at an average pressure drop across the cell lnlet-exhaust mani-folds of 5 psio The in~tial reservoir electrolyte tempera-ture was 25Co The temperature of the battery after a full charge was 32Co If no electrolyte circulation was pro~ided 30 during charging, the battery temperature after a full charge :
. .
46,215 ., . ~070376 would have been in excess of 70C, which would be very detrimental to the operating life of the electrodes and separators.
In operation, the epoxy resin sealing system at the edge sides of the plates in the stack-up and the top of each cell proved to be leakproofO Uniform and very efficient and ef~ectlve cooling of the cells during charging was accomplished~ No deleterious self-discharge was observed by ~- .
electrlcal conductivity of the electrolyte circulation 10 plumbing systemO There was no excessive increase in pres- ~.
sure drop in a cell after 2,000 charge-discharge cyclesO
This shows evldence of no plugging of the plate channels due to plate swelling or loose active material. The use of 2 channels per nickel plate, constltutlng 4% of one side of ~:~
the nlckel plate surface area, provided adequate cooling ~or thls system. More channel~, up to 10% of plate surface area, could be added where more cooling and le~s active material volume is required~
-19- ' .
, ,,, " " , ~ , ~ " .. , , ,, ", ,",, .,, , .. ". .. . . .. . . ..
1070376 ~ ~
and oxygen gases at one location, where proper safety pre-cautions can be taken; and maki~g the system simpler, so that cell size changes can be readlly and inexpenslvely accomplished O
To solve all o~ these problems the battery has to have the following ~eatures: leakproof, since electrolyte ls circulating under pressure, all the cell cases and plumblng connections must be of the highest order of hermeticity; low pressure drop, to keep the size of the circulation pump small and for leakage and safety reasons; hi~h resistance in the- electrolyte connections between cells, to minlmize self-discharge; unlform pressure drop among all cells, to allow the cells to be connected in parallel arrangement and stlll achieve uniform flow through each cell; and most lmportantly, uniform flow throughout the cell cross-sectlon, so that all plates receive adequate electrolyte flow and assurance that electrolyte flows through the stack-up of a cell, not around them, so that the most effectlve coollng durlng charglng ls achlevedO
SUMMARY OF THE INVENTION
The battery herein descrlbed solves all of the listed problems and has the requlred features descrlbed above. Electrolyte ls circulated through the battery and a reservoir contalning a coollng mechanism by means of a pump.
Any heat exchanglng means, such as cooling water clrculated through colls ln the reservo~r, can be used to cool the electrolyte~ Electrolyte ls clrculated at rates adequate to remove the heat generated by varlous charge, dlscharge rates. The reservoir and pump are attached to the battery with quick disconnect couplings so the battery may be dls-46,215 :, . . .
~070376 -~ -~ .
charge~ wlth or without them~ Electrolyte le~el and specific ~ ; ., ~ ..
gravity are maintained by adding water to the reservoir to maintain a constant height levelO The battery system is vented to the atmosphere at the reservoir through a barrier venting means, which allows explosive hydro~en and oxygen to escape. All of the listed necessary features for this improved circulating electrolyte battéry are accomplished by the foll-owing means:
a) The cell electrodes of each stack-up are sealed and encapsulated in a molded case3 preferably by means of an epoxy resin sealant filler, whlch adheres to the case wall~, terminals, and electrolyte inlet and exhaust tubes, ;
providlng an effective hermetic seal ln all of these loca-tionsO : ";
b) Low and uniform cell to cell pressure drops, and uniform flow of electrolyte through the cell stack-ups is accomplished by providlng channels in the plates, as by cuttlng or pressing narrow slits in themO The channels are spaced apart for effective cooling and constitute no more than 10% of the plate surface area.
c) Electrolyte ls forced to flow through these channels, and not around the perlphery of the cell stack-ups, by the tight fit between the stack faces and the wide ;
front case walls, and by filling the space between the stack-up edges and the narrow edge case walls with a suit-able sealant filler. The filler can be any number of materials, such as a liquid, curable, plastic resin or rubber, foam in place materials, already foamed material cut to fit, etc.
~30 d) High electrical resistance in the electrolyte 46,215 :' '.
-:
~o70376 , plumbing network is accomplished by the use of long inlet and exhaust tubes. The inlet tube preferably extends from the top to the bottom of the cell, while the exhaust tube is preferably formed in a coil at the top of the cellO The manifolds connecting cells with each other are preferably above the cells, which allows electrolyte to drain back into the cells when circulation StopsD This latter feature re-duces the electrical path between cells to the conductivity of the electrolyte film which clings to the piping wallsO
.
Fl~w of electrolyte through the system can be summarlzed as follows: Reservoir; Pump; Battery manifold Cell inlet manifolds; Cell electrolyte lnlet tubes; Cell reservoirs; Through channels in sealed cell stack-ups; Cell :
electrolyte outlet tubes; Cell exhaust manifold; Battery manifold, and the~ on to the Reservolr for coollng.
This lmproved, cell stack-up electrolyte flow system offers many advantages and benefits over other con-ventlonal systems, some of which are:
a) Effective cooling of the stack-up enables higher charge rates to be employed, thus reducing charge tlmeO A typical cycle of charging/discharging, at the C/2 rate, malntains the temperature at between 30C and 35C
wlth circulationO Without circulation, temperatures would exceed 70C, which severely hampers battery life.
b) The hermeticlty of the system elimlnates many safety hazards such as spllls and mists which lead to short circuit grounding paths and potential failures.
c) The parallel flow arrangement, with associated plumbing, insures each cell of proper malntenance, and ell-~30 minates failures due to over or under filling and improper 46,215 - . .
10~70376 ~ ~
speclflc gravity~ ~ ~
.. .
d) The plumbing also prov-~des for safe gas handling ;~
and lends itself well for elimination of hydrogen and oxygen formed during charg~ng. :
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understandlng of the invention, reference may be made to the preferred embodiment, exemplary of the lnventlon, shown in the accompanying drawings, in whlch:
Flgure 1 ls a three dimensional vlew of a circu-latlng electrolyte battery module containlng flve series :
connected battery cells;
Flgure 2 ls a top view, partlally in sectlon, of the battery module of Figure l; i Figure 3 is a side view, partially in section, of the battery module of Figure 2, along the line III;
Figure 4 is a cross-section of the battery module of Figure 2, along llne IV, showlng an electrode plate, having spaced apart channels, sealed into the container, :.:
20 cell inlet manifold, cell electrolyte inlet tube, cell ~ !:
reservolr, and the cell electrolyte outlet tube;
Figure 5 is a cross-section of the plate stack-up of one embodiment of a cell, showlng the sealed electrode plate sldes and edge~, and the channels ln the plate stack-up prov~ding uniform fIow of electrolyte through the stack-up rather than around the periphery of the stack-up; and Figure 6 is a schematlc vlew of an assembly of battery modules fed by a circulatlng electrolyte system, with associated electrolyte cooling reservoir and pump.
. ...... .. . . . . . - . -~ . .. . .. .
46,215 107(~376 DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Figure 1 of the drawings, a battery module 10 is shown with associated dimensions, which ~ -may vary greatly depending on battery use. The battery ~
module, containing at least one cell, can comprise case 11, :
whlch may be, for example, a metal, rubber or plastic box.
Each cell 12 is in its own case or conta~ner havlng flat ~ront and edge wallsO The battery module case 11 is optional, `
however, as the separate cells may be held together solely by the cell exhaust manifold 13 and cell inlet manifold 14, shown disposed in a parallel arrangementO The cells may also be held together by electrical connections between the terminal studs 150 Of course, any other holding or clamping means can be used to hold the separate cells together, such as a bottom U plate, shown as 17 in the drawing, which would be used without the battery module caseO
Figure 2 shows a top view of the battery module with terminal studs 150 Also shown is the coiled cell electrolyte outlet tube 21, which attaches to the cell exhaust manifold 13 at opening 22. The cell electrolyte lnlet tube is shown as 230 Figure 3 also shows the position o~ these tubes within a cell, where the bottom of the cell electrolyte inlet tube ls shown as 300 Flgure 4 shows a cross-section of a preferred cell 12 of thls inventionO Cell electrolyte circulation means, tubular cell inlet manifold 14 and cell exhaust manlfold 13, are preferably disposed in a parallel arrangementO These electrolyte circulation means are preferably connected above the cells to allow electrolyte to drain back into the cells when clrculation stops~ This reduces the electrical path 46,215 ~
.
~, ,.
between cells when electrolyte is not circulating, to the -:
conductivity of the electrolyte film which clings to the manifold tube wallsO
The inlet and outlet manifold tubes will have a ~.
relatively large internal cross-sectionO This provldes low ,..
fluid flow resistance and minimum pressure drop across the cell, which ls requlred to minimize the pressure necessary ~:
for adequate electrolyte flowO The cell inlet and outlet manifold tubes have a long length for hig~ electrical re- .
10 sistance when filled with electrolyteg which is required to -`
minimize current leakage from cell to cellO
Preferably, electrolyte is pumped up through the electrode stack-up, so that hydrogen and oxygen gases gene-rated during charglng are easily exhausted to the cooling reservoir without dangerous pressure build-up In the cell .
of Figure 4, electrolyte, from the manifold 14, flows from . .
the top of the cell case to the bottom of the cell stack-up, ~.
by means of the cell electrolyte inlet tube 23. Cell elec- ~. :
trolyte inlet tube 23 extends from the top of the electrode :
stack-up down along one edge of the battery cell between the edge side of the stack-up and the edge wall of the cell -caseO Then, the tube bends around the bottom Or the stack-up and extends lnto the bottom cell reservoir 40 The cell stack-up, comprising a series of alternate positive and negatlve electrode plates, one of which is shown as 41, may rest on plastic, rubber or foam blocks 42 to form the bottom reservoir 40O
Thus, electrolyte flowing into the cell case will fill up the bottom electrolyte reservoir formed by the blocks or other suitable stack-up supporting means. The 46,215 1~70376 electrolyte will then be forced up the channels 43 in the -electrode platesO
Referring now to Figure 5, a top cross-section view of electrode plate 41, and other alternating positive and negative plates maklng up one type of cell electrode stack-up 50 is shownO The channels 43 can be formed by cutting narrow slits in the electrode plates, by coining the plates to form narrow channels in the plates, or by any other suitable meansO
The cross-section of the channel can be clrcular as shown, square, or any other configurationO The channels can be on both sides of each plate lf desiredO The channels need not be on both positive and negative plates as shown, but may, for example, be pressed only into the positive or negative plates, so that channels would appear on alternate platesO
The channel should not extend through the electrode plate becau~e thls would substantlally reduce the conduc-tivity of the plateO The channel area can comprise from about 0O5% to 10% of the plate face area. If the channels constitute over 10% of the plate area, excessive active material is lost with a reduction in battery performance.
Usually 1 to 6 channels per plate are adequate for good electrolyte circulation and battery coolingO
Channels on one side of the plate, as shown in F~gure 5, are pre~erred, since this provides a strong elec-trode structure requiring minimal machining or pressingO
Not shown are plate separators, which may be made of a con-tlnuous or perforated film of cellulose, polypropylene, nylon or other suitable insulating material between or _g_ . 46,215 " .,. , , ,~ .
1070376 ~; ~
wrapped in serpenti~e ~ashion around each plate~ ~he se- :~
parators of course should be compattble wlth the electro- .::~
lyteO For adequate cooling it i~ essential that electrolyte flows only along the channels between the electro~e plates -~
in the stack-up, and not around the sides and edges of the stack-up, although there may be minimal electrolyte seepage through the platesO :
To provide a hermetic seal and to assure that no electrolyte flows around the stack-up, the spaces 44 between the edge s~de of the stack-up 45 and the edge wall of the cell case 46, shown in Flgures 4 and 5, are filled with a suitable sealantO The se~lant can be a curable 9 llquid, epoxy resin, or any other plastic resln, rubber or other materlal, such as polypropylene foam or polyethylene foam, effective to hermetically seal the space 44 yet not be chemlcally degraded by the electrolyte Thls sealant ~lller will seal and encapsulate the side edge o~ the stack-up and the middle portlon of the electrolyte lnlet tubeO Preferably the sealant wlll be ;.
curable at about 25C~ Prevention of electrolyte flow between the wide face slde of the cell stack-up and the flat, front cell case walls can be accompllshed by a tlght ~lt and intimate contact between the two, as shown in Flgure 5 at 510 This arrangement seals the sides of the electrode stack-ups, i~e the edge sldes and the wlde face sides but not the top and bottom of the stack-upO
The electrode plates making up the stack-ups in the cells are9 preferably~ flexible, porous plaques of about 75% to 95% porosity, made from dlf~usion bonded meta-l flbers, such as nickel flbers, but preferably steel wool or nlckel --10~
~ 46,215 , , 1~70376 coated steel wool, as descrlbed in UO~O Patent 3,895,~600 ~ ~ :
Other type plates, such as porous slntered nickel powder or cast porous nlckel can be used, but have not been found as effective as the expanslble fiber metal platesO The fiber ~:
metal plates can expand and contract during "formation", to provide superior active material loadingc These plaques contaln active battery materlal distributed upon and disposed within the ~ore volume of the plaqueO When, for example, an iron-nickel cell is to be -:
10 made, the actlve material of the positive electrode plates . ~
may comprise Nl(OH)2, with small effective amounts o~ Co(OH)2 .
actlvating addltlveO The negative electrode plates may comprise an iron oxide, such as FeO, Fe203, Fe304, Fe203 H20 or their mixtures, with small effective amounts of sulfur contalnlng actlvating additives fused thereon or mixed therewith, as described in UOSo Patent 3,853,624. Of course other types of posltive and negative active materials and other additlves can be used~
Each electrode plaque has an electrical lead tab :
spot welded or otherwise attached, generally to a colned top areaO These lead tabs 47 provide means for making electrlcal connectlons to the plates. Termlnal connection lugs 48 are attached to the lead tabs to electrically connect the posi-tive and negative plates to the terminal studs 150 Once the electrolyte flows up through the channels 43 of the stack up, in the preferred embodiment of this invention, it exits from the cell through the cell electro-lyte outlet tube 21 and cell exhaust manlfold 130 The length of the cell electrolyte outlet tube 21 can preferably be increased, to provide high electrical resistance in the 46~215 ,.:
electrolyte plumbing network., by making it in a coiled or ~:
similar configuration to that shown in Figures 2 and 4O
In all cases9 the plumbing in the cell and battery module, such as inlet a.nd outlet tubes and manifolds should be made of a non-conduct~ng tubular material such as poly~ ~ :
propylene, polyethylene, polyvinyl chloride, acrylonitrile .-~
butadiene styrene, nylon or other type plastic or rubber .:.
materlals not degradable by the elect~olyteO These non~
conducting tubes and mani~olds can be attached by a suitable adhesive such as epoxy or polyvinyl chloride adhesiveO
To insure electrolyte exit through the electrolyte exhaust tube 21, the space 49 between the top of the cell case and the top of the exhaust tube entrance may be filled with a suitable sealant similar to that described herein-above~ This would also provide a top for the cell caseO In order to provide such a top, a barrier can be placed over the top of the bottom opening of the cell electrolyte outlet tube, and sealant in~ected or poured on top of the barrier to encapsulate the top of the outlet tube, the top of the ~ .
lnlet tube and the terminalsO
Referring now to Figure 6; a battery is built by conneeting cell inlet manifolds 14 and outlet manifolds 13 preferably in parallelO To facilitate constructing a hlgh power battery, several sets of cells, iOeO sets of battery modules 10, are fa~tened in place with all the fluld flow ln parallel to minlmize the pressure required for the syætem and to provide uniform cell to cell coollngO The battery modules can then be positioned to build a complete high power battery ~ystem for the voltage and space requirements of each individual application Figure 6 shows a high power ` 46,215 battery consisting of three banks of three battery modules.
Each battery module contains five cells.
The modules are connected by common battery mani- ;
fold electrolyte circulation means 60, the length and posi-tion of which are dependent on the battery layoutO The battery manifolds can be detached from the heat exchanger means 61 and the electrolyte pumping means 62 by quick dlsconnect couplings 63, so that the high power battery can -be discharged wlthout the heat exchanger and pumpO The heat exchanger or cooling means can comprise an electrolyte cooling reservoir 64 contaln ng cold water cooling coils 65.
A radiator or other cooling apparatus could be added to the system for air cooling to replace or supplement the cooling colls. Electrolyte will be circulated by the pump at rates effective to remove the heat generated by the various charge, discharge ratesO
Electrolyte level and specific gravity are con-trolled by adding water to the electrolyte cooling reservoir 64 through inlet 66, to maintain a constant height level in the cellsO The battery system is vented to the atmosphere, preferably at the reservoir, by any suitable means, such as, for example, a barrler venting means 67, which can be a slntered ceramic barrler, whlch allows hydrogen and oxygen to escape whlle acting as a flame and explosion barrler A
bubble tube extending from the openlng in the reservoir lnto the bottom of an open container of water can also be used to allow gas to escapeO The alkaline electrolyte generally used will be a 10 wto% to 35 wt.% KOH or NaOH aqueous solu-tion wlth preferably about 2 to 20 grams/liter of Li(OH)2.
No gase~ are added to the electrolyte.
4 6 ~ 2 15 ~070376 -`~
" '' ~, Example 1 An iron-nickel hlgh power battery system sililar ~ -to that shoNn in Figures 1 through 6 was constructedO The battery plates were made .~rom nickel plated steel fibers :,.
~ormed into plaquesO Fibers approximately 0 001 x 00 002 x 0025 inch long were used in the flexible, expansible, fiber metal plaquesO They were then heated, in a protective : ~ :
,., environment, causing metal to metal diffusion bonds to form at fiber contact pointsO There was no melting of fibers so 10 as to assure maximum pore volumeO ~ '`~"`
The "nickel" plaques were then colned to about 8 percent- o~ theoretlcal densityg 92 percent porous, and the "iron" plaque bodie~ were coined to 17 percent of theoretical ~ ~.
density, 83 percent porousO Each nickel plaque had two vertical 1/8" wide pressed channelsO The plaque was about 6.5" wide and ~bout 0O09ll thicko The channels were about 0O08ll deepO The channels comprised about 4% of the plaque surface areaO A steel sheet was then spot welded onto the top coined port.ion of the plaques to form electrical lead 20 tab connections, shown as 47 in Figure 4O ' :
The tron active material comprised sulfurized :~
magnetlc iron oxlde particlesO The magnetic iron oxide, had a compo~ition of about 79 percent Fe2O3, 22 percent FeO and 1 percent impuritiesO Enough sulfur was used to provide a ratio o~ sulfur to iron oxide of about Oo l to 10 percent of the sulfurized iron oxideO This additive helped keep the iron active material surface in the active state The "iron" plaques were loaded with the sulfurized .
magnetic iron oxide by a wet pasting techniqueO These iron .
electrode plates were then sized and driedO They contained ~ 46,215 ~ 07037~ `
about 1.5 to about 1.9 grams/cm3 plaque volume of sulfurized iron active material.
The nickel active material comprised nickel h~-droxide doped with a small amount of cobalt h~droxide. The nickel plaques were loaded b~ an impregnation "formation"
impregnation technique. The~ contained about 0.9 to about 1.3 grams/cm3 of active material. The "iron" and "nickel"
plates were then read~ for the cell stack-up operation.
A batter~ module having dimensions about 7" wide x 10" deep x 10" high, as shown in Figure 1 was used and consisted of five cells. The cell cases, made of high density pol~eth~lene and having an open top, were about 7"
wide x 2" deep x 10" high. The~ would contain the electrode stack-ups.
In the stack-up operation, iron and nickel plates were alternatel~ stacked, insulated from each other with a sexpentine wound polyprop~lene separator, and then the terminal connection lugs, shown as 48 in Figure 4, were iner~ gas welded to the tabs to pro~ide means for making electrical connections to the plates. The cell stack-up, along with a 3/16" inside diameter pol~prop~lene cell elec-trolyte inlet tube, was then inserted into the cell case on top of two pol~eth~lene foam blocks, about 1' wide x 2"
deep x 5/8" high, shown as 42 in Figure 4.
The inlet tube ran down the edge side of the stack-up and next to the narrow edge wall of the cell con-tainer, curving at the bottom to run underneath the cell stack-up. The inlet tube stopped at about the middle of the bottom reservoir, shown as 40 in Figure 4, formed b~ the cell stack-up and foam blocks 42. A groove had been formed 46,215 1~7C~376 ln the foam block whlch the inlet tube ran through so that the inle~ tube would fit around the bottom of the stack~up This provided cells having Lnserted electrode stack-ups supported on the bottom with foam blocks9 having an electrolyte inlet tube running into a reservoir at the bottom of the cellO The space, shown as 44 in Figure 4, be-tween edge sides of the stack-up and the 2" edge walls of the cell contai.ners was unfilledO ~ -A viscous9 room temperature curable epoxy resin was then dispensed, ~rom an in~ection gun, ~nto thls space 44 between each edge side of the stack-ups and each edge wall of the cell case, to act as a hermetic sealant and to encapsulate the stack-up between the foam blocks and the top of the electrode stack-upO The top and bottom of the stack-up remained unsealedO This would force the pumped electro-lyte, from the bottom reservoir, to run through the plate channels 43 to the top of the cell rather than around the plates.
The top of the cell was fitted with a 5/16" inside diameter polypropylene cell electrolyte outlet tubeO This tube, shown as 21 in the drawlngs, is ln a coiled conflgur-ation. It starts Just above the electrode stack-ups, under the cell exhaust manifold and runs across the cell width, coiling around the cell electrolyte lnlet tube, running back across the cell, and fitting into the cell exhaust manifold, as shown in Figures 2, 3 and 4O
In order to ~orm a top on the cell, the cell .
electrolyte outlet tube was held in place, with the outlet opening Just at the top of the cell stack-up, with polyvinyl .. ;
chloride adheslve tapeO The tape had holes for the Dottom ~- 46,215 -,~
portion of the electrolyte outlet tube, the positive and negative interconnection lugs and the top of the electrolyte inlet tube to fit throughO A top reservoir volume was thus formed bekween the tape and the top of the stack-upsO
A vigcous, room temperature curable epoxy resin was then dispensed, from an in~ection gun, on top of the .
tape to encapsulate the top portion of the cell electrolyte outlet and inlet tubes and the intercell connection lugs. `
Thus epoxy resin formed the top of the cellO
The iron plaque in the stack-up was still in un-formed conditionO An electrolyte solution containing 25 wt.% KOH and 15 grams/liter of Li(OH)2 was po~red lnto the cell and "formation" of the iron plaques was accomplsihed by a series of charge-discharge cyclesO ~
Cells were then matched and electrically connected ~-to form a five cell battery moduleO Four modules were placed in series and 1/2" inside diameter polyvinyl chloride cell inlet manlfolds and 3/4" inside diameter cell exhaust manlfolds were connected to the cell electrolyte inlet tubes and cell electrolyte outlet tubes respectively with room temper~ture curable epoxy resin glueO Each module was slmilar to that shown in Figure 1, ~ith the manifolds 13 and 14 in parallel on top of the cellsO The modules were assem- ~
bled as shown in Figure 6, only there were four banks of - ::
modules, each bank contain four connected battery modules, each module containing five cellsO Thusg there were a total of 16 modules or 80 cells to form the high power batteryO
Referring to Figure 6, the cell inlet manifolds 14 and exhaust manifolds 13 were connected to common 1" inside diameter polyvinyl chloride battery manifolds with flexible -17- :, : - .
~ 46,215 :::
.,,i polyvinyl chlorlde hose and hose clamps The pump manifolds were connected to a 1/4 HoPo pump and a 25 gallon electro-lyte reservolr 61 made of polyvinyl chlorideO
The reser~oir had a closed top and a cer~mic flame : ~
arrestor barrier vent 66, to exhaust hydrogen or oxygen ~ ~ `
present in the electrolyte due to charglng, and an inlet 67 for adding water or electrolyteO The cooling coils 65 were made: from 20' of coiled 1/2" lnside diameter stainless steelO Cold water was circulated through the colls to cool 10 the circulating electrolyteO `~.
The electrolyte solutton used. in the system con~
tained 25 wt % KOH and 15 grams/liter of Li(OH)2o No gases were added to the electrolyteO The pump and reservoir were connected to the battery modules through dlsconnect valves in the common pump manlfolds so that the high power battery -could be discharged without themO
The assembled hlgh power battery was then bench :~
tested through several 3 hour charge9 2 hour discharge test cycles to establish a capacity ratingO Best results yielded about 17 KWH, or 20 Wh/pounds of cellO The battery was then operated in several electrical vehicles in excess of 100 cycles O
The 80 cell (96 volt) circulatlng electrolyte battery was charged uslng a C/2 (100 AmpO ) charge rate for 3 hoursO Total electrolyte flow was 9 galO per m~nO, at an average pressure drop across the cell lnlet-exhaust mani-folds of 5 psio The in~tial reservoir electrolyte tempera-ture was 25Co The temperature of the battery after a full charge was 32Co If no electrolyte circulation was pro~ided 30 during charging, the battery temperature after a full charge :
. .
46,215 ., . ~070376 would have been in excess of 70C, which would be very detrimental to the operating life of the electrodes and separators.
In operation, the epoxy resin sealing system at the edge sides of the plates in the stack-up and the top of each cell proved to be leakproofO Uniform and very efficient and ef~ectlve cooling of the cells during charging was accomplished~ No deleterious self-discharge was observed by ~- .
electrlcal conductivity of the electrolyte circulation 10 plumbing systemO There was no excessive increase in pres- ~.
sure drop in a cell after 2,000 charge-discharge cyclesO
This shows evldence of no plugging of the plate channels due to plate swelling or loose active material. The use of 2 channels per nickel plate, constltutlng 4% of one side of ~:~
the nlckel plate surface area, provided adequate cooling ~or thls system. More channel~, up to 10% of plate surface area, could be added where more cooling and le~s active material volume is required~
-19- ' .
, ,,, " " , ~ , ~ " .. , , ,, ", ,",, .,, , .. ". .. . . .. . . ..
Claims (10)
1. A circulating electrolyte battery comprising in combination: at least one cell containing a stack-up of electrode plates having a face side and an edge side; an electrolyte cooling means containing electrolyte spaced from said cell; electrolyte pumping means connected to said cooling means, and electrolyte circulation means connected from the pumping means to the cell and from the cell to the cooling means; wherein the improvement comprises sealing the face side and edge side of the stack-up, and providing at least one channel in at least one electrode plate in each stack-up, wherein the channel constitutes from about 0.5% to 10% of the electrode plate surface area, so that pumped electrolyte flows only through the channels in the stack-up.
2. The circulating electrolyte battery of claim 1, wherein the stack-up is disposed within a cell case and comprises at least one flat positive electrode plate and at least one flat negative electrode plate, each containing active material distributed upon the flat surface and dis-posed within the pore volume of the plate, an alkaline electrolyte flows from the bottom to the top of the stack-up, and the channel is on the surface of but not through the electrode plate.
3. The circulating electrolyte battery of claim 2, wherein the plates in each stack-up have a separator therebetween, the stack-up is disposed within a cell case such that the face sides of the stack-up fit in intimate contact with the cell case and the edge sides of the cell stack-up are sealed by a curable sealant, to provide a hermetic seal between the sides of the stack-up and the cell case.
4. The circulating electrolyte battery of claim 2, wherein the electrolyte circulation means comprise paral-lel inlet and exhaust means which are positioned on top of the battery cells and can be detached from the pumping and cooling means.
5. The circulating electrolyte battery of claim 2, wherein the plates comprise 75 to 95 percent porous metal fiber plaques, the negative plates comprising iron oxide active material and the positive plates comprising nickel hydroxide active material.
6. The circulating electrolyte battery of claim 3, wherein the channels are pressed into the surface of the electrode plate, the sealant is an epoxy rosin and the cooling means comprises a reservoir containing means for venting hydrogen and oxygen gas from the electrolyte.
7. A circulating electrolyte battery comprising:
a plurality of connected cells; a cooling reservoir tank containing electrolyte spaced from said cells; pumping means connected to said reservoir tank; and electrolyte circula-tion means connected from the pumping means to the cells and from the cells to the reservoir; wherein each cell comprises a case having flat front walls and edge walls within which is disposed:
A. at least one flat positive electrode plate con-taining active material, B. at least one flat negative electrode plate con-taining active material; wherein the positive and negative plates comprise a cell stack-up having flat face sides and edge sides, said cell stack-up being disposed within the cell case such that the flat face side of the stack-up fits in intimate contact with the flat front cell case walls, and the edge sides of the cell stack-ups do not con-tact the edge walls of the cell case, providing a space which is filled with a sealant, C. an electrolyte inlet tube connected to the pump said inlet tube running from the top of the cell case to the bottom of the cell stack-up, D. an electrolyte outlet tube at the top of the cell stack-up connected to the reservoir, wherein at least one plate has at least one channel, running from the bottom to the top thereof, through which electro-lyte flows from the bottom to the top of the cell stack-up and into the electrolyte outlet tube, said channel being in the plate structure and constituting from about 005% to 10%
of the flat surface area of the plate, the electrolyte being forced to flow only through the channels, in the cell stack-up, and E. means for making electrical connections to the respective plates.
a plurality of connected cells; a cooling reservoir tank containing electrolyte spaced from said cells; pumping means connected to said reservoir tank; and electrolyte circula-tion means connected from the pumping means to the cells and from the cells to the reservoir; wherein each cell comprises a case having flat front walls and edge walls within which is disposed:
A. at least one flat positive electrode plate con-taining active material, B. at least one flat negative electrode plate con-taining active material; wherein the positive and negative plates comprise a cell stack-up having flat face sides and edge sides, said cell stack-up being disposed within the cell case such that the flat face side of the stack-up fits in intimate contact with the flat front cell case walls, and the edge sides of the cell stack-ups do not con-tact the edge walls of the cell case, providing a space which is filled with a sealant, C. an electrolyte inlet tube connected to the pump said inlet tube running from the top of the cell case to the bottom of the cell stack-up, D. an electrolyte outlet tube at the top of the cell stack-up connected to the reservoir, wherein at least one plate has at least one channel, running from the bottom to the top thereof, through which electro-lyte flows from the bottom to the top of the cell stack-up and into the electrolyte outlet tube, said channel being in the plate structure and constituting from about 005% to 10%
of the flat surface area of the plate, the electrolyte being forced to flow only through the channels, in the cell stack-up, and E. means for making electrical connections to the respective plates.
8. The circulating electrolyte battery of claim 7, wherein the plates comprise 75 to 95 percent porous, diffusion bonded, metal fiber plaques, the negative plates comprising iron oxide active material with an effective amount of sulfur containing additive and the positive plates comprising nickel hydroxide active material with an effec-tive amount of cobalt containing additive, and the outlet tube has a coiled configuration.
9. The circulating electrolyte battery of claim 7, wherein the channels are disposed on but not through the surface of the electrode plate, the sealant is an epoxy resin and the bottom surface of the cell stack-up rests on a separated support to provide a reservoir underneath the cell stack-up.
10. The circulating electrolyte battery of claim 8, containing means for venting hydrogen and oxygen gas from the electrolyte.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65534776A | 1976-02-05 | 1976-02-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1070376A true CA1070376A (en) | 1980-01-22 |
Family
ID=24628525
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA270,862A Expired CA1070376A (en) | 1976-02-05 | 1977-02-01 | Circulating electrolyte battery system |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5296326A (en) |
| CA (1) | CA1070376A (en) |
| DE (1) | DE2704314A1 (en) |
| FR (1) | FR2340624A1 (en) |
| GB (1) | GB1576273A (en) |
| IT (1) | IT1080816B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4188462A (en) * | 1978-10-30 | 1980-02-12 | The Continental Group, Inc. | Power module assembly with monopolar cells |
| DE3001732C2 (en) * | 1980-01-18 | 1984-02-16 | Jack Evans Edgmont Holmbury St. Mary Surrey Thompson | Device for generating electrical energy |
| IT1270584B (en) * | 1993-03-09 | 1997-05-06 | Olimpio Stocchiero | QUICK-CHARGE ACCUMULATOR CONTAINER |
| IT1270552B (en) * | 1993-06-09 | 1997-05-06 | Olimpio Stocchiero | QUICK-CHARGE ACCUMULATOR CONTAINER WITH ELECTROLYTE DISTRIBUTION CHANNELS PRINTED ON THE COVER |
| JP2007157675A (en) * | 2005-12-06 | 2007-06-21 | Akira Narisada | Storage battery |
| US9941548B2 (en) * | 2013-06-20 | 2018-04-10 | Landmark Battery Innovations, Inc. | Nickel iron battery |
| KR20250006342A (en) * | 2015-11-18 | 2025-01-10 | 인비니티 에너지 시스템즈 (캐나다) 코포레이션 | Electrode assembly and flow battery with improved electrolyte distribution |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR368474A (en) * | ||||
| DE1771330B2 (en) * | 1968-05-08 | 1973-10-04 | Varta Batterie Ag, 3000 Hannover | Electric battery made of nickel-cadium accumulators with alkaline electrolytes pumped around during charging and / or discharging |
| IT945267B (en) * | 1970-12-09 | 1973-05-10 | Deutsche Automobilgesellsch | GALVANIC CELL WITH DISTRIBUTION DEVICE FOR FLUID CURRENTS |
| US3779813A (en) * | 1972-08-21 | 1973-12-18 | Occidental Energy Dev Co | Manifold system for electrical energy storage systems |
-
1977
- 1977-02-01 CA CA270,862A patent/CA1070376A/en not_active Expired
- 1977-02-02 DE DE19772704314 patent/DE2704314A1/en not_active Withdrawn
- 1977-02-04 JP JP1156877A patent/JPS5296326A/en active Pending
- 1977-02-04 IT IT4153077A patent/IT1080816B/en active
- 1977-02-04 FR FR7703259A patent/FR2340624A1/en active Granted
- 1977-02-04 GB GB4684/77A patent/GB1576273A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1576273A (en) | 1980-10-08 |
| FR2340624B1 (en) | 1982-10-15 |
| FR2340624A1 (en) | 1977-09-02 |
| JPS5296326A (en) | 1977-08-12 |
| IT1080816B (en) | 1985-05-16 |
| DE2704314A1 (en) | 1977-08-18 |
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