CA2187583A1 - Deep-dishcharge battery separator - Google Patents
Deep-dishcharge battery separatorInfo
- Publication number
- CA2187583A1 CA2187583A1 CA002187583A CA2187583A CA2187583A1 CA 2187583 A1 CA2187583 A1 CA 2187583A1 CA 002187583 A CA002187583 A CA 002187583A CA 2187583 A CA2187583 A CA 2187583A CA 2187583 A1 CA2187583 A1 CA 2187583A1
- Authority
- CA
- Canada
- Prior art keywords
- separator
- battery
- tubular
- deep
- active material
- 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.)
- Abandoned
Links
- 239000000919 ceramic Substances 0.000 claims abstract description 27
- 239000000463 material Substances 0.000 claims description 20
- 239000011149 active material Substances 0.000 claims description 9
- 239000007774 positive electrode material Substances 0.000 claims description 9
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 claims description 5
- 229910052863 mullite Inorganic materials 0.000 claims description 5
- 238000010276 construction Methods 0.000 description 13
- 210000004027 cell Anatomy 0.000 description 11
- 239000002253 acid Substances 0.000 description 10
- 238000013461 design Methods 0.000 description 9
- SAPGTCDSBGMXCD-UHFFFAOYSA-N (2-chlorophenyl)-(4-fluorophenyl)-pyrimidin-5-ylmethanol Chemical compound C=1N=CN=CC=1C(C=1C(=CC=CC=1)Cl)(O)C1=CC=C(F)C=C1 SAPGTCDSBGMXCD-UHFFFAOYSA-N 0.000 description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- 239000010439 graphite Substances 0.000 description 7
- 229910002804 graphite Inorganic materials 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 230000001351 cycling effect Effects 0.000 description 6
- 239000003792 electrolyte Substances 0.000 description 5
- 239000000835 fiber Substances 0.000 description 5
- 239000004020 conductor Substances 0.000 description 4
- 238000001125 extrusion Methods 0.000 description 4
- 239000004033 plastic Substances 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 239000004927 clay Substances 0.000 description 3
- 239000002270 dispersing agent Substances 0.000 description 3
- 239000000945 filler Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229920000609 methyl cellulose Polymers 0.000 description 3
- 239000001923 methylcellulose Substances 0.000 description 3
- 235000010981 methylcellulose Nutrition 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000003365 glass fiber Substances 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000004580 weight loss Effects 0.000 description 2
- 239000005995 Aluminium silicate Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000002991 molded plastic Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000000979 retarding effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/14—Electrodes for lead-acid accumulators
- H01M4/16—Processes of manufacture
-
- 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
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
- H01M50/434—Ceramics
-
- 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
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M50/491—Porosity
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Ceramic Engineering (AREA)
- Inorganic Chemistry (AREA)
- Cell Separators (AREA)
- Secondary Cells (AREA)
Abstract
A tubular, rigid, porous, ceramic separator for a rechargeable, deep-discharge battery assembly, the separator having a porosity greater than 40%. A plurality of battery cells, each embodying such separators, are assembled with a common terminal to form the positive electrode in a motive traction battery.
Description
P00030/Gardner et al.
DEEP-DISCHARGE BATTERY SEPARATOR
FELD OF THE INVENTION
Deep-discharge batteries and tubular, porous, ceramic battery separators for such batteries.
BACKGROUND OF THE INVENTION
The oldest and best known type of rechargeable battery is the lead-acid battery.The present invention is primarily concerned with heavy duty batteries of this type designed to provide deep-discharge. In particular, it is directed to tubular separators for use in such batteries.
Heavy duty, lead-acid batteries are commonly used as the power source in fork trucks, golf carts, other electrically powered road and service vehicles and in marine applications, such as boats, ships and submarines. Both tubular and flat plate battery designs are used for this type battery. The present application is concerned with the former design, that is, the tubular design. In particular, it is directed at tubular separators for use as a component in such deep-discharge batteries.
Presently, the positive plates in a tubular battery consist of a series of parallel, porous tubes. Each tube has a centralized lead conductor surrounded by active material.
The tubes are presently made from woven, braided, or felted fibers. Such materials are resistant to acid attack and to the oxidizing environment of lead-acid batteries. However, they lack structural integrity and do not lend themselves to convenient, automated m~nllf~cture.
DEEP-DISCHARGE BATTERY SEPARATOR
FELD OF THE INVENTION
Deep-discharge batteries and tubular, porous, ceramic battery separators for such batteries.
BACKGROUND OF THE INVENTION
The oldest and best known type of rechargeable battery is the lead-acid battery.The present invention is primarily concerned with heavy duty batteries of this type designed to provide deep-discharge. In particular, it is directed to tubular separators for use in such batteries.
Heavy duty, lead-acid batteries are commonly used as the power source in fork trucks, golf carts, other electrically powered road and service vehicles and in marine applications, such as boats, ships and submarines. Both tubular and flat plate battery designs are used for this type battery. The present application is concerned with the former design, that is, the tubular design. In particular, it is directed at tubular separators for use as a component in such deep-discharge batteries.
Presently, the positive plates in a tubular battery consist of a series of parallel, porous tubes. Each tube has a centralized lead conductor surrounded by active material.
The tubes are presently made from woven, braided, or felted fibers. Such materials are resistant to acid attack and to the oxidizing environment of lead-acid batteries. However, they lack structural integrity and do not lend themselves to convenient, automated m~nllf~cture.
An integrated cell for a heavy duty, deep-discharge battery normally consists ofseveral tubes. These may be employed individually, or, alternatively, they may be joined together in what is known as a gauntlet construction. This construction integrates several individual tubes into a single structure. The tubes are mounted at their base with a plastic 5 bottom bar. Conventional negative electrodes and separators may be used to complete the tubular design battery.
The important consideration for deep-discharge, deep-cycling batteries for traction applications is maximum cycle life with high energy density. However, light weight is not always desirable in certain applications. For example, a forklift battery must be heavy, 10 because the weight of the battery is generally used to counterbalance the payload. The life of these batteries is increased by employing thick plates with high paste density, a high temperature cure with high humidity, low electrolyte density, high quality, organic-based s,eparators, and one or more layers of glass fiber matting.
The flat pasted (Faure) positive plate is typical for deep cycling batteries in the 15 United States. However, some cycling batteries in the United States, and most cycling batteries in the rest of the world, are built with tubular or gauntlet type positives. the tubular construction minimi7es both grid corrosion and shedding of active material. Flat-pasted negative plates are used in conjunction with these positives, and the cells are of the outside-negative design. Batteries for traction and deep-cycle applications have similar 20 performance with either pasted or tubular positive plates. However, the tubular or gauntlet plates show lower polarization losses because of the larger active surface area, better retention of the positive active material, and reduced loss on idle or stand.
The present invention provides an extruded, ceramic, tubular separator to replace the current woven fiber gauntlet and the glass mat separator.
SUMMARY OF THE INV~NTION
The present invention resides in a porous, rigid, ceramic, tubular separator for a tubular, deep-discharge (deep cycling) battery. It further resides in a deep-discharge 30 tubular battery embodying such tubular bodies as separators.
The important consideration for deep-discharge, deep-cycling batteries for traction applications is maximum cycle life with high energy density. However, light weight is not always desirable in certain applications. For example, a forklift battery must be heavy, 10 because the weight of the battery is generally used to counterbalance the payload. The life of these batteries is increased by employing thick plates with high paste density, a high temperature cure with high humidity, low electrolyte density, high quality, organic-based s,eparators, and one or more layers of glass fiber matting.
The flat pasted (Faure) positive plate is typical for deep cycling batteries in the 15 United States. However, some cycling batteries in the United States, and most cycling batteries in the rest of the world, are built with tubular or gauntlet type positives. the tubular construction minimi7es both grid corrosion and shedding of active material. Flat-pasted negative plates are used in conjunction with these positives, and the cells are of the outside-negative design. Batteries for traction and deep-cycle applications have similar 20 performance with either pasted or tubular positive plates. However, the tubular or gauntlet plates show lower polarization losses because of the larger active surface area, better retention of the positive active material, and reduced loss on idle or stand.
The present invention provides an extruded, ceramic, tubular separator to replace the current woven fiber gauntlet and the glass mat separator.
SUMMARY OF THE INV~NTION
The present invention resides in a porous, rigid, ceramic, tubular separator for a tubular, deep-discharge (deep cycling) battery. It further resides in a deep-discharge 30 tubular battery embodying such tubular bodies as separators.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, FIGURE 1 is a side view in cross-section of a single, tubular battery cell in accordance with the invention.
FIGURE 2 is a partial side view of an integrated positive cell for a deep-discharge battery in accordance with the invention.
FIGURE 3 is an exploded side view depicting a modified form of the invention.
FIGURE 4 is a perspective view of the modified form of FIGURE 3 .
DESCR~PTION OF TH[E INVENTION
Our present invention adopts the basic structural features of current heavy duty?
deep-discharge, tubular cell batteries. In such batteries, the positive plates consist of a series of parallel porous tubes. Each tube has a centralized lead conductor surrounded by active material. The tubes are presently made from woven, braided, or felted fibers which are resistant to the acid electrolyte and to the oxidizing environment of lead-acid batteries.
The tubes may be used individually. Alternatively, they may be stitched together, (gauntlet construction) to produce a single structure with several tubes. The tubes are sealed at their base with a plastic bottom bar. Conventional negative electrodes and separators are used to complete the tubular design battery.
The present invention is primarily concerned with providing an improved tubular separator for a deep-discharge battery. Therefore, reference is made to the prior art for details regarding construction and operating characteristics for this type of battery. A
typical description may be found at pages 219-227 of a text by Clive D. S. Tuck entitled "Modern Battery Technology" and published by Ellis Horwood (1991).
Our invention arises from the concept of employing porous, ceramic, tubular bodies as separators in deep-discharge batteries. These ceramic separators are substituted for the fibrous tubes and porous separators currently used for this purpose in deep-discharge batteries. They provide for ease of assembly compared with the non-rigid, tubular separators.
-In producing such ceramic, tubular separators, we adopt and modify practices andprocedures from the art of ceramic body extrusion. Thus, a batch of raw materials is mixed to provide a homogeneous mass of suitable viscosity for extrusion. This mass is fed through an extruder with a die designed to extrude a continuous length of ceramic 5 tubing.
Our preferred ceramic materials for ceramic separator purposes are composed of alumina or mullite alone or mixed with each other. Sources of these materials in powder form are mixed with methylcellulose, a dispersant, graphite and water to form extrudable mixtures. The mixtures are extruded in tubular form having a desired wall thickness, and 10 are fired to produce porous, tubular separators.
Chemical durability is necessary since the separator is exposed to the electrolyte.
The industry test used for a lead-acid battery separator involves exposure of the material to sulfuric acid solution of 1.28 specific gravity for 72 hours at 70~C. The material must exhibit a weight loss that is less than 5% to be acceptable. For convenience in 15 coordin~tin~ testing, we have adopted a more stringent test that involves exposure to 40% sulfuric acid for 96 hours at 95~C. Further, we have required that weight loss in this more stringent test not exceed about 2%.
Finally, a porous material must have good wickability. This is a measure of the ability for the pores to take up electrolyte by capillary action. For example, a glass fiber 20 mat separator typically will allow a sulfuric acid electrolyte to rise to a height of 7. 5 cm (3") in a period of 3 minlltes.
The ceramic material in the walls of an extruded separator has an inherent porosity of about 30-40%. However, a greater value is generally considered necessary to provide a sufficiently low impedance to produce a viable battery. A porosity greater than about 25 50% is preferred.
In order to enhance the porosity in an extruded ceramic, the batch prepared for extrusion may incorporate a combustible or evanescent filler in amounts up to about 75%.
We prefer powdered graphite as the filler. When a body is extruded, it is fired to remove the filler, thereby enhancing the porosity of the body to values greater than 40%, 30 preferably greater than 60%.
-An electrical circuit, such as a battery, contains resistance (R), capacitance (C) and inductance (L). An impedance Z is defined to calculate the overall retarding effect on current of components with R, L or C. The impedance is critical to operation of a battery and expresses the system's slow response to a stimulus, namely the effect on current flow 5 upon application of a stimulus (charging and discharging). Power (E in watts) in the direct current (DC) mode of batteries is defined as the product of the current (I in amperes) and the impedance (Z in ohms) for the DC components of the battery only.
Impedance invariably reduces the theoretical voltage of a battery to a lower working voltage.
Successful battery performance requires ability to accept and maintain a charge.To this end, the impedance value must be relatively low. During battery formation a total energy input is targeted in terms of a fixed ampere-hours/pound (Ah/Ib). This input must occur with the voltage in any cell not exceeding a certain level. Normal practice is to provide a total energy input of 185 Ah/lb while maintaining the impressed voltage below 15 2. 7 volts. If the porosity of a separator is too low, the impressed voltage will exceed the permissible limit. This necessitates cutting back the energy input level, a situation that interferes with proper formation of the battery and increases manufacturing time and cost.
Heavy duty, lead-acid batteries are used as the power source in fork trucks, golf carts, other electrically powered road and service vehicles and marine applications. The 20 primary requirement for these heavy duty batteries is to have good cycling capability.
Most types of traction battery are guaranteed for 1200 cycles or five years service. Two types of battery design are widely used for this application, i.e. tubular and flat plate construction.
The positive plates in the tubular cell consist of a series of parallel porous tubes 25 each having a centralized lead conductor surrounded by active material. The tubes are presently made from woven, braided, or felted fibers which are resistant to acid and the oxidizing environment of lead-acid batteries. The tubes may be used individually or stitched together (gauntlet construction) to produce a single structure with several tubes.
The tubes are sealed at the base with a plastic bottom bar. Conventional negative 30 electrodes and separators are used to complete the tubular design battery.
-In the tubular battery cell design, the extruded, ceramic, tubular separators replace the current woven fiber gauntlet and the glass mat separator. An electrode construction is formed in the center of the extruded ceramic body. The exterior of the extruded body acts as the separator between the electrodes. The ceramic gauntlet/separator may be 5 processed in a one piece construction to provide an active positive electrode using existing tubular battery technology.
The ceramic tubular construction can also be made in two pieces with channels which are pasted with active materials. The pasted halves are joined together and a centralized lead conductor spline incorporated to produce a tubular positive 10 electrode/separator. Plastic holders may be used to cap and fasten the tubular body together. The ceramic body is tailored to the desired porosity and impedance to produce a battery with the desired deep-discharge characteristics.
Ceramic separators provide significant advantages for use in heavy duty commercial batteries. The materials can be processed into a variety of shapes and sizes 15 with a wide range of porosity and pore sizes. These can be tailored to each battery's requirements.
The materials are strong and do not shred or break apart during normal use of the battery. The materials do not break while under compression and prevent active material from falling off the electrodes extending the life of the battery. The materials exhibit 20 tortuous porosity which deters the ability of dendrites from moving through the separator and shorting the cell. The strength of the ceramic separators makes the materials ideal for automated processing and for use in either vertical or horizontal positions. The ceramic tubes also supply structural strength to the battery.
The use of the ceramic, tubular construction potentially revolutionizes the 25 fabrication process of deep-discharge batteries. It significantly mechanizes the process of m~nllf~cturing, and improves performance by increasing energy and power densities.
FIGURE 1 in the accompanying drawing is a side view in cross-section of a singletubular component 10 of a battery cell illustrating the invention. Component 10 embodies porous tubular body 12 which functions as a separator. Separator 12 is filled with a 30 positive active material 14. This may be the material commonly employed as a porous coating for a positive electrode or grid. A metal wire or rod 16 is then inserted in the -active material 14 of component 10 to function as the positive electrode. Normally, a complete cell in a battery will have a negative electrode on each side of component 10 or a series of such components.
Typically, a series of components 10 are combined to form an integrated electrode. The series may, for example, number 15-20. The individual electrodes 16 may be connected in known manner to form the integrated electrode.
FIGURE 2 is a schematic, partial view of an integrated electrode. The FIGURE
shows three components 10 electrically connected by a metal bar 18 to produce integrated electrode 20. The opposite ends ofthe components 10 may be held in a support member, for example, a molded plastic holder 22.
FIGURE 3 is an exploded side view illustrating an alternative, two-piece construction for an individual tubular component 30. In component 30, the ceramic separator takes the form of channeled, semi-cylindrical bodies 32 which may be identical in shape and material. Channels 34 of bodies 32 are filled with positive active material 36 corresponding to that shown in FIGURE 1 at 14. Likewise, metal electrode member 38 is embedded in material 36. Bodies 32 are then sealed together to form a component 30 corresponding to component 10.
A series of components 30 may then be assembled to form an integrated electrode in the manner described above. It will be appreciated that a gauntlet-type construction may be produced by molding bodies having multiple, parallel channels, rather than a single channel as shown.
FIGURE 4 is a perspective view showing tubular component 30 as a unitary body formed by sealing together bodies 32.
SPECIFIC EMBODIMENTS
Development work has been largely carried out with our preferred materials, extruded alumina, mullite, or alumina/mullite mixtures. These materials have been mixed with graphite prior to extrusion. As noted earlier, the graphite burns out of the extruded 30 material to provide bodies with improved porosities.
2~ 87583 TABLE I shows batch compositions in parts by weight for a series of mixtures which, when extruded and fired, provide bodies composed of 33% mullite and 67%
alumina.
TABLE I
Batch Materials 1 2 3 4 5 6 7 Platelet clay 16.6614.13 11.63 9.14 7.80 5.82 4.16 Stacked clay 5.544.71 3.88 3.05 2.49 1.94 1.39 Calcined clay 27.6123.47 19.34 15.19 12.42 9.66 6.90 Alumina 50.7342.67 35.16 27.63 22.6017.58 12.56 Graphite -- 15 30 45 55 65 75 Methyl cellulose 3 3 3 3 3 3 3 Dispersant 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Water 27.5 27.5 27.5 27.5 27.5 27.5 27.5 The basic batches, prior to addition of graphite, were originally designed for preparation of support substrates exposed to temperature cycling. Accordingly, 20 combinations of platelet, stacked and calcined clays (kaolin) were employed to control expansion effects by crystal orientation. The therrnal expansion e~ects of the different clays, not of significance here, are explained in detail in United States PatentNo. 3,885,977 (Lachman et al.) TABLE II shows batch compositions in parts by weight for a similar series of 25 materials which, when extruded and fired, produce alumina bodies of varying porosity.
g TABLE II
Batch Materials 8 9 10 11 Alumina 100 75 50 25 Graphite -- 25 50 75 Methyl cellulose 3 3 3 3 Dispersant 0 7 0.7 0 7 0 7 Water 27 5 27 5 27 5 27 5 TABLE III shows properties for fired, porous bodies produced from the batches shown in TABLES I and II.
TABLE III
MOR Porosity Pore Size ExampleMpa(psi) (%) (Microns) 1 51 2 (7400) 40 4 0 49 2 276(4010) 507 060 3 14 9 (2160) 58.6 1.17 4 6 7 ( 973) 68.6 3.88 3 0 ( 431) 72.5 5.30 6 1 75(253) 768 664 7 1.6 ( 232) 82.1 8.43 8 28 7 (4180) 40 3 1.07 9 7.4 (1080) 57.1 1.91 3.1 (456) 602 10.21 11 <0.7 (<100) 85.0 13.93
In the accompanying drawings, FIGURE 1 is a side view in cross-section of a single, tubular battery cell in accordance with the invention.
FIGURE 2 is a partial side view of an integrated positive cell for a deep-discharge battery in accordance with the invention.
FIGURE 3 is an exploded side view depicting a modified form of the invention.
FIGURE 4 is a perspective view of the modified form of FIGURE 3 .
DESCR~PTION OF TH[E INVENTION
Our present invention adopts the basic structural features of current heavy duty?
deep-discharge, tubular cell batteries. In such batteries, the positive plates consist of a series of parallel porous tubes. Each tube has a centralized lead conductor surrounded by active material. The tubes are presently made from woven, braided, or felted fibers which are resistant to the acid electrolyte and to the oxidizing environment of lead-acid batteries.
The tubes may be used individually. Alternatively, they may be stitched together, (gauntlet construction) to produce a single structure with several tubes. The tubes are sealed at their base with a plastic bottom bar. Conventional negative electrodes and separators are used to complete the tubular design battery.
The present invention is primarily concerned with providing an improved tubular separator for a deep-discharge battery. Therefore, reference is made to the prior art for details regarding construction and operating characteristics for this type of battery. A
typical description may be found at pages 219-227 of a text by Clive D. S. Tuck entitled "Modern Battery Technology" and published by Ellis Horwood (1991).
Our invention arises from the concept of employing porous, ceramic, tubular bodies as separators in deep-discharge batteries. These ceramic separators are substituted for the fibrous tubes and porous separators currently used for this purpose in deep-discharge batteries. They provide for ease of assembly compared with the non-rigid, tubular separators.
-In producing such ceramic, tubular separators, we adopt and modify practices andprocedures from the art of ceramic body extrusion. Thus, a batch of raw materials is mixed to provide a homogeneous mass of suitable viscosity for extrusion. This mass is fed through an extruder with a die designed to extrude a continuous length of ceramic 5 tubing.
Our preferred ceramic materials for ceramic separator purposes are composed of alumina or mullite alone or mixed with each other. Sources of these materials in powder form are mixed with methylcellulose, a dispersant, graphite and water to form extrudable mixtures. The mixtures are extruded in tubular form having a desired wall thickness, and 10 are fired to produce porous, tubular separators.
Chemical durability is necessary since the separator is exposed to the electrolyte.
The industry test used for a lead-acid battery separator involves exposure of the material to sulfuric acid solution of 1.28 specific gravity for 72 hours at 70~C. The material must exhibit a weight loss that is less than 5% to be acceptable. For convenience in 15 coordin~tin~ testing, we have adopted a more stringent test that involves exposure to 40% sulfuric acid for 96 hours at 95~C. Further, we have required that weight loss in this more stringent test not exceed about 2%.
Finally, a porous material must have good wickability. This is a measure of the ability for the pores to take up electrolyte by capillary action. For example, a glass fiber 20 mat separator typically will allow a sulfuric acid electrolyte to rise to a height of 7. 5 cm (3") in a period of 3 minlltes.
The ceramic material in the walls of an extruded separator has an inherent porosity of about 30-40%. However, a greater value is generally considered necessary to provide a sufficiently low impedance to produce a viable battery. A porosity greater than about 25 50% is preferred.
In order to enhance the porosity in an extruded ceramic, the batch prepared for extrusion may incorporate a combustible or evanescent filler in amounts up to about 75%.
We prefer powdered graphite as the filler. When a body is extruded, it is fired to remove the filler, thereby enhancing the porosity of the body to values greater than 40%, 30 preferably greater than 60%.
-An electrical circuit, such as a battery, contains resistance (R), capacitance (C) and inductance (L). An impedance Z is defined to calculate the overall retarding effect on current of components with R, L or C. The impedance is critical to operation of a battery and expresses the system's slow response to a stimulus, namely the effect on current flow 5 upon application of a stimulus (charging and discharging). Power (E in watts) in the direct current (DC) mode of batteries is defined as the product of the current (I in amperes) and the impedance (Z in ohms) for the DC components of the battery only.
Impedance invariably reduces the theoretical voltage of a battery to a lower working voltage.
Successful battery performance requires ability to accept and maintain a charge.To this end, the impedance value must be relatively low. During battery formation a total energy input is targeted in terms of a fixed ampere-hours/pound (Ah/Ib). This input must occur with the voltage in any cell not exceeding a certain level. Normal practice is to provide a total energy input of 185 Ah/lb while maintaining the impressed voltage below 15 2. 7 volts. If the porosity of a separator is too low, the impressed voltage will exceed the permissible limit. This necessitates cutting back the energy input level, a situation that interferes with proper formation of the battery and increases manufacturing time and cost.
Heavy duty, lead-acid batteries are used as the power source in fork trucks, golf carts, other electrically powered road and service vehicles and marine applications. The 20 primary requirement for these heavy duty batteries is to have good cycling capability.
Most types of traction battery are guaranteed for 1200 cycles or five years service. Two types of battery design are widely used for this application, i.e. tubular and flat plate construction.
The positive plates in the tubular cell consist of a series of parallel porous tubes 25 each having a centralized lead conductor surrounded by active material. The tubes are presently made from woven, braided, or felted fibers which are resistant to acid and the oxidizing environment of lead-acid batteries. The tubes may be used individually or stitched together (gauntlet construction) to produce a single structure with several tubes.
The tubes are sealed at the base with a plastic bottom bar. Conventional negative 30 electrodes and separators are used to complete the tubular design battery.
-In the tubular battery cell design, the extruded, ceramic, tubular separators replace the current woven fiber gauntlet and the glass mat separator. An electrode construction is formed in the center of the extruded ceramic body. The exterior of the extruded body acts as the separator between the electrodes. The ceramic gauntlet/separator may be 5 processed in a one piece construction to provide an active positive electrode using existing tubular battery technology.
The ceramic tubular construction can also be made in two pieces with channels which are pasted with active materials. The pasted halves are joined together and a centralized lead conductor spline incorporated to produce a tubular positive 10 electrode/separator. Plastic holders may be used to cap and fasten the tubular body together. The ceramic body is tailored to the desired porosity and impedance to produce a battery with the desired deep-discharge characteristics.
Ceramic separators provide significant advantages for use in heavy duty commercial batteries. The materials can be processed into a variety of shapes and sizes 15 with a wide range of porosity and pore sizes. These can be tailored to each battery's requirements.
The materials are strong and do not shred or break apart during normal use of the battery. The materials do not break while under compression and prevent active material from falling off the electrodes extending the life of the battery. The materials exhibit 20 tortuous porosity which deters the ability of dendrites from moving through the separator and shorting the cell. The strength of the ceramic separators makes the materials ideal for automated processing and for use in either vertical or horizontal positions. The ceramic tubes also supply structural strength to the battery.
The use of the ceramic, tubular construction potentially revolutionizes the 25 fabrication process of deep-discharge batteries. It significantly mechanizes the process of m~nllf~cturing, and improves performance by increasing energy and power densities.
FIGURE 1 in the accompanying drawing is a side view in cross-section of a singletubular component 10 of a battery cell illustrating the invention. Component 10 embodies porous tubular body 12 which functions as a separator. Separator 12 is filled with a 30 positive active material 14. This may be the material commonly employed as a porous coating for a positive electrode or grid. A metal wire or rod 16 is then inserted in the -active material 14 of component 10 to function as the positive electrode. Normally, a complete cell in a battery will have a negative electrode on each side of component 10 or a series of such components.
Typically, a series of components 10 are combined to form an integrated electrode. The series may, for example, number 15-20. The individual electrodes 16 may be connected in known manner to form the integrated electrode.
FIGURE 2 is a schematic, partial view of an integrated electrode. The FIGURE
shows three components 10 electrically connected by a metal bar 18 to produce integrated electrode 20. The opposite ends ofthe components 10 may be held in a support member, for example, a molded plastic holder 22.
FIGURE 3 is an exploded side view illustrating an alternative, two-piece construction for an individual tubular component 30. In component 30, the ceramic separator takes the form of channeled, semi-cylindrical bodies 32 which may be identical in shape and material. Channels 34 of bodies 32 are filled with positive active material 36 corresponding to that shown in FIGURE 1 at 14. Likewise, metal electrode member 38 is embedded in material 36. Bodies 32 are then sealed together to form a component 30 corresponding to component 10.
A series of components 30 may then be assembled to form an integrated electrode in the manner described above. It will be appreciated that a gauntlet-type construction may be produced by molding bodies having multiple, parallel channels, rather than a single channel as shown.
FIGURE 4 is a perspective view showing tubular component 30 as a unitary body formed by sealing together bodies 32.
SPECIFIC EMBODIMENTS
Development work has been largely carried out with our preferred materials, extruded alumina, mullite, or alumina/mullite mixtures. These materials have been mixed with graphite prior to extrusion. As noted earlier, the graphite burns out of the extruded 30 material to provide bodies with improved porosities.
2~ 87583 TABLE I shows batch compositions in parts by weight for a series of mixtures which, when extruded and fired, provide bodies composed of 33% mullite and 67%
alumina.
TABLE I
Batch Materials 1 2 3 4 5 6 7 Platelet clay 16.6614.13 11.63 9.14 7.80 5.82 4.16 Stacked clay 5.544.71 3.88 3.05 2.49 1.94 1.39 Calcined clay 27.6123.47 19.34 15.19 12.42 9.66 6.90 Alumina 50.7342.67 35.16 27.63 22.6017.58 12.56 Graphite -- 15 30 45 55 65 75 Methyl cellulose 3 3 3 3 3 3 3 Dispersant 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Water 27.5 27.5 27.5 27.5 27.5 27.5 27.5 The basic batches, prior to addition of graphite, were originally designed for preparation of support substrates exposed to temperature cycling. Accordingly, 20 combinations of platelet, stacked and calcined clays (kaolin) were employed to control expansion effects by crystal orientation. The therrnal expansion e~ects of the different clays, not of significance here, are explained in detail in United States PatentNo. 3,885,977 (Lachman et al.) TABLE II shows batch compositions in parts by weight for a similar series of 25 materials which, when extruded and fired, produce alumina bodies of varying porosity.
g TABLE II
Batch Materials 8 9 10 11 Alumina 100 75 50 25 Graphite -- 25 50 75 Methyl cellulose 3 3 3 3 Dispersant 0 7 0.7 0 7 0 7 Water 27 5 27 5 27 5 27 5 TABLE III shows properties for fired, porous bodies produced from the batches shown in TABLES I and II.
TABLE III
MOR Porosity Pore Size ExampleMpa(psi) (%) (Microns) 1 51 2 (7400) 40 4 0 49 2 276(4010) 507 060 3 14 9 (2160) 58.6 1.17 4 6 7 ( 973) 68.6 3.88 3 0 ( 431) 72.5 5.30 6 1 75(253) 768 664 7 1.6 ( 232) 82.1 8.43 8 28 7 (4180) 40 3 1.07 9 7.4 (1080) 57.1 1.91 3.1 (456) 602 10.21 11 <0.7 (<100) 85.0 13.93
Claims (10)
1. A tubular, rigid, porous, ceramic separator for a rechargeable, deep-discharge battery assembly, the separator having a porosity greater than 40%.
2. A tubular separator in accordance with claim 1 comprising two annular, semi-cylindrical bodies of porous ceramic sealed together at their side peripheries.
3. A battery cell comprising a tubular, rigid, porous, ceramic separator having a porosity of greater than 40%, a positive active material filling the interior of the separator, and a positive electrode embedded and extending from the positive active material.
4. A battery cell in accordance with claim 3 wherein the separator is formed as two annular, semi-cylindrical bodies, each body is filled with a positive active material, a positive electrode is embedded in the active material and the two bodies are sealed together.
5. A battery cell in accordance with claim 3 wherein the electrode is connected to a terminal common to a plurality of individual cells.
6. In a deep-discharge battery comprising a plurality of individual, tubular battery cells held in a mounting and having a common terminal, each individual battery cell comprising a tubular, rigid, porous, ceramic separator having a porosity of greater than 40%, a positive active material filling the interior of the separator, and a positive electrode embedded and extending from the positive active material.
7. A deep-discharge battery in accordance with claim 6 wherein at least one individual cell is formed as two annular, semi-cylindrical bodies, each body is filled with a positive active material, a positive electrode is embedded in the active material and the two bodies are sealed together.
8. A deep-discharge, light weight battery, in accordance with claim 6, where therigid, porous, ceramic separator provides a structural support that replaces the structural support provided by the lead grid material.
9. A battery cell in accordance with claim 1, 3 or 6 wherein the ceramic separator is composed of a material selected from alumina, mullite, and mixtures thereof.
10. A battery cell in accordance with claim 1, 3, or 6 wherein the separator has a porosity greater than 60%.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US583495P | 1995-10-23 | 1995-10-23 | |
| US60/005,834 | 1995-10-23 | ||
| US08/679,693 | 1996-07-11 | ||
| US08/679,693 US5738955A (en) | 1995-10-23 | 1996-07-11 | Deep-discharge battery separator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2187583A1 true CA2187583A1 (en) | 1997-04-24 |
Family
ID=21717987
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002187583A Abandoned CA2187583A1 (en) | 1995-10-23 | 1996-10-10 | Deep-dishcharge battery separator |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5738955A (en) |
| EP (1) | EP0771039A1 (en) |
| JP (1) | JPH09167607A (en) |
| BR (1) | BR9605151A (en) |
| CA (1) | CA2187583A1 (en) |
| MX (1) | MXPA96005057A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL131842A (en) * | 1999-09-09 | 2007-03-08 | Unibat Ltd | Chargeable electrochemical cell |
| US6211652B1 (en) | 2000-02-04 | 2001-04-03 | Milwaukee Electric Tool Corporation | Discharge protection apparatus for a battery-powered device and a method of preventing overdischarge of a battery |
| US8372545B2 (en) | 2007-03-05 | 2013-02-12 | Advanced Membrane Systems, Inc. | Separator for non-aqueous lithium-ion battery |
| US8304113B2 (en) * | 2007-03-05 | 2012-11-06 | Advanced Membrane Systems, Inc. | Polyolefin and ceramic battery separator for non-aqueous battery applications |
| US20100239899A1 (en) * | 2009-03-23 | 2010-09-23 | Joe Brown | Gauntlet motive battery |
| US8808914B2 (en) | 2012-01-13 | 2014-08-19 | Energy Power Systems, LLC | Lead-acid battery design having versatile form factor |
| US9595360B2 (en) | 2012-01-13 | 2017-03-14 | Energy Power Systems LLC | Metallic alloys having amorphous, nano-crystalline, or microcrystalline structure |
| US9263721B2 (en) | 2012-01-13 | 2016-02-16 | Energy Power Systems LLC | Lead-acid battery design having versatile form factor |
| NL2035013B1 (en) * | 2023-06-06 | 2024-12-12 | Real Scientists Ltd | A ceramic separator for energy storage device and method of manufacture the same |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USRE15067E (en) * | 1921-03-22 | Battery and separator therefor | ||
| US3489610A (en) * | 1964-06-30 | 1970-01-13 | Mc Donnell Douglas Corp | Battery having a porous insoluble hydrous inorganic oxide separator |
| US3379570A (en) * | 1965-10-21 | 1968-04-23 | Mc Donnell Douglas Corp | Battery containing a sintered aluminosilicate separator |
| US3446668A (en) * | 1966-04-01 | 1969-05-27 | Mc Donnell Douglas Corp | Inorganic battery separator and battery |
| US3446669A (en) * | 1966-06-07 | 1969-05-27 | Mc Donnell Douglas Corp | Sintered metal oxide battery separator and battery |
| US3647542A (en) * | 1966-12-19 | 1972-03-07 | Mc Donnell Douglas Corp | Solid-fluid battery |
| US3661644A (en) * | 1966-12-19 | 1972-05-09 | Mc Donnell Douglas Corp | Battery construction having a honeycomb matrix with cells filled with different electrode materials |
| US3607403A (en) * | 1968-11-15 | 1971-09-21 | Mc Donnell Douglas Corp | Self-charging battery incorporating a solid-gas battery and storage battery within a honeycomb matrix |
| US3885977A (en) | 1973-11-05 | 1975-05-27 | Corning Glass Works | Anisotropic cordierite monolith |
| US4160068A (en) * | 1978-11-21 | 1979-07-03 | Ford Motor Company | Storage battery |
| JPS59139560A (en) * | 1983-01-28 | 1984-08-10 | Matsushita Electric Ind Co Ltd | Electrode for lead storage battery |
| US4648177A (en) * | 1983-10-21 | 1987-03-10 | Gates Energy Products, Inc. | Method for producing a sealed lead-acid cell |
| US5126218A (en) * | 1985-04-23 | 1992-06-30 | Clarke Robert L | Conductive ceramic substrate for batteries |
| US5112703A (en) * | 1990-07-03 | 1992-05-12 | Beta Power, Inc. | Electrochemical battery cell having a monolithic bipolar flat plate beta" al |
| US5208121A (en) * | 1991-06-18 | 1993-05-04 | Wisconsin Alumni Research Foundation | Battery utilizing ceramic membranes |
| SE510853C2 (en) * | 1991-07-01 | 1999-06-28 | Volvo Technology Transfer Ab | Bipolar battery |
| JPH062822A (en) * | 1992-06-23 | 1994-01-11 | Koatsu Gas Kogyo Co Ltd | Flame diminishing element |
-
1996
- 1996-07-11 US US08/679,693 patent/US5738955A/en not_active Expired - Lifetime
- 1996-10-10 CA CA002187583A patent/CA2187583A1/en not_active Abandoned
- 1996-10-17 BR BR9605151A patent/BR9605151A/en not_active Application Discontinuation
- 1996-10-21 EP EP96116871A patent/EP0771039A1/en not_active Ceased
- 1996-10-22 MX MXPA96005057A patent/MXPA96005057A/en unknown
- 1996-10-23 JP JP8280677A patent/JPH09167607A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| BR9605151A (en) | 1998-07-14 |
| US5738955A (en) | 1998-04-14 |
| EP0771039A1 (en) | 1997-05-02 |
| MXPA96005057A (en) | 2002-05-23 |
| JPH09167607A (en) | 1997-06-24 |
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| Date | Code | Title | Description |
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| FZDE | Discontinued |
Effective date: 20001010 |