KR890002673B1 - Secondary electrical energy storage device and electrode therefor - Google Patents

Abstract

A diamensionally stable electrode for use in a secondary electrical energy storage device comprises an electrode body of an electrically conductive carbonaceous material, having a skeletal orientation of oriented fused benzenoidal structure moieties, at least at or near the surface, and a current collector electrically associated therewith, wherein the carbonaceous material has a Youngs modulus of form 1,000,000 to 55,000,000 psi and undergoes a physical dimensional change of less than 5% during repeated electrical charge and discharge cycling.

Description

Secondary electric energy storage device and its electrode

1, 2 and 3 show the relationship between the discharge amount and the voltage.

4 shows the relationship between maximum power density versus state of charge.

5 is a relationship diagram of time-phase voltage at the high rate power discharge.

The present invention relates to a carbonaceous material associated with an electron collector as an electrode for a secondary electrical energy storage device.

Carbonaceous electrodes are very stable in electrolyte systems containing anions such as perchlorate and hexafluoroacetate when used under normal operating temperatures or atmospheres.

In other words, the carbonaceous material does not cause a noticeable irregular expansion and contraction that may occur during operation of the secondary electrical energy accumulator during overelectrical discharge and charging.

As electrode materials, many patents and technical papers have been published for electrical energy storage devices using carbonaceous materials such as carbon or graphite. Nearly the first was a Lacranche type battery in 1866, where carbon was used as the electron collector in the primary battery of Zn / NH ₄ Cl / MnO ₂ . Since then, carbon has been widely used as an electrode component of primary batteries, primary fuel cells, secondary fuel cells, secondary batteries and capacitors. The function of carbon or graphite in these above mentioned devices mainly works with current collectors or reactive materials to form new fluorine compounds, which have different structures and properties from the original carbon / graphite, and in recent years It acts to form a base with the ions of the electrolyte. Examples of such prior art devices include the following. Coliman Primary Battery, Panasonic Lithium Battery Document, US Patent Nos. 4,271,242, 3,700,502 and 4,224,389, Fuel Cells of Japanese Patent Publication No. 54-082043, US Patent No. 4,037,025, published in US Patent No. 2,597,451. Some rechargeable secondary fuel cells from DuCie, rechargeable fuel cells using active graphite, Hart's US Patent No. 4,251,568 using graphite as current collector and Mr. Buddy Ruth's US patent using high-area carbon (graphite) Capacitors in US Pat. No. 3,700,975 or West German Patent No. 3,231,243, and rechargeable secondary batteries disclosed in Vinion's US Pat. Nos. 3,844,837 and 4,009,323. Some of these devices use ionic salts that are soluble in non-conductive solvents.

The carbonaceous material described in the patent is a material that is graphitized or carbonized until it is electrically conductive.

These materials are produced from polyacetylene, polypheninyl, polyacrylonitrile, and petroleum, which has a slight conductivity by carbonizing or graphitizing heating preliminary materials. Graphite used in the prior art includes RPG (thermally strengthened graphite), R-1 reactor graphite, PGCP (hot graphite graphite), GRAFOIL (Union Carbide Corporation trademark) equipped with expanded and compressed graphite, and the like.

Doping of similar carbonaceous materials is published in the "Conductive Polymer R & D Continuous Growth Method", published on April 19, 1982, published in Chemical and Engineering News Volume 60, page 16, page 29, page 33, Journal of the Journal of Electrochemistry and Electrochemical Science, Vol. 118, No. 12, pp. 1886 to 1890, published in December 1971, and No. 59, 41, pp. 34 to 34, published October 12, 1981. Published on page 35, "Classic Low Weight Polymer Cells."

The problem with the above-described battery is that the carbonaceous material deteriorates when the electric charge and discharge are repeated, thereby shortening the lifetime of the electrode made of the material.

For example, U.S. Patent No. 3,844,837 (Vinion C) is used to inject Li ₂ O into a chip from a LiCF ₃ SO ₃ -dimethylsulfite (DMSU) electrolyte to make a positive electrode and copper as a negative electrode. Storage batteries are described. The graphite electrode is made of R-1 nuclear graphite (commercially available from Great Lakes Carbon Company) and is to be peeled off after nine charge and discharge cycles. The patentee of this patent concluded that he was not hit by a test with graphite.

Many other graphites have been used, but thermally-enhanced graphite has not yielded more than 33 failures. The alumni of D.C. and below were formed by forming a hole in which a chemical reaction occurred in a high area carbon or graphite material, but the conductivity was low due to lack of continuity of the carbon surface. Moreover, these materials did not maintain the perfect structure and the standard stability necessary for the formation of the carbon composites required to prolong the recharge life of secondary batteries.

In the experiments according to the present invention using GRAFOIL (trade name), the first electric charge and the RPG (ultra high temperature) graphite electrode also failed. Therefore, more than 20% of the anode made of RPG graphite was lost due to peeling of chips and powders by 27 electric charges and discharges.

In addition to damage to the electrode as a result of the expansion and contraction of the electrode body, this expansion and contraction caused the graphite plate to peel off, thereby increasing the twisting of the charge and discharge. Through these experiments, it was confirmed that the peeling of the graphite plate during the development of the present invention occurs as the graphite material is repeatedly charged and discharged.

According to one aspect of the present invention, there is provided a secondary electric energy storage device having an electrode body of electrically conductive carbonaceous material having a skeletal orientation at least in the vicinity or on the surface thereof and a current collector associated therewith, wherein the carbonaceous material Has a Young's modulus of more than 1 million (6.9 GPa) and can make the physical specification fluctuation less than 5% even during repeated electric charge and discharge.

According to another feature of the invention, there is provided a housing having an electrical non-conductive inner surface and a secondary electrical energy accumulator having at least one battery in the housing and having an outer surface or a thin film body through which moisture does not pass, wherein each battery It is provided with a pair of electrically conductive electrodes insulated from each other and said housing actually contains a nonaqueous electrolyte, and at least one electrode of each battery is an electrode of the present invention.

According to still another aspect of the present invention, there is provided a secondary electrical energy storage device including a housing having an electrical non-conductive inner surface and an outer surface or a thin film body having at least one battery in the housing and through which moisture does not pass. The cell has at least a pair of electrically conductive electrodes insulated from each other, the housing actually contains a non-aqueous electrolyte and each electrode of each cell is an electrode as claimed in claims 1, 2 and 3 Each of the electrodes does not require the selection of the polarity upon recharging, and some or all of the electrodes can be reversed without damage.

The electrodes can be separated by distances or by electrically nonconductive materials.

[Physical properties]

It is preferable that the electrical conductivity of the carbonaceous electrode falls within the following physical properties.

(1) The Young's modulus is 1,000,000 psi (6.9 GPa) or more, preferably 10,000,000 psi (69 GPa) to 55,000,000 psi (380 GPa), and most preferably 20,000,000 to 45,000,000 psi (138 Gpa to 311 GPa).

(2) The aspect ratio is preferably 100: 1 or higher. The aspect ratio is the ratio of the length-to-diameter ratio l / d of the fibers or filament strands of the carbonaceous material or the length to depth when the carbonaceous material is formed of the flat sheet.

(3) All structural and mechanical properties, which can be made of carbonaceous material (non-woven or man-made fibers or films from knit, knit or burned filaments), have the desired sheet or plate-like carbon upon at least 100 charge and discharge cycles. It should be such that it does not require a support such as a pressure plate (cotton film or meso) in order to maintain the material.

(4) The surface area associated with activated carbon should be at least 0.1 m 2 / g, preferably at least 50 m 2 / g or at most 10 m 2 / g and more preferably at most 5 m 2 / g.

(5) Morphological integrity of the carbonaceous material may be obtained without the use of a metal current collector frame or other support that forms the edge of the electrode when the size of the carbonaceous material is 6.45 cm ² (1 in ² ) or more than 930 cm ² (144 in ² ). It should be possible to maintain the sheet form.

(6) The secondary electric energy storage device which embodies the electrode of this invention has virtually only 100 ppm or less of moisture. Suitably the water content is best at 20 ppm or less and at most 10 ppm. The device of the present invention can be operated even when the moisture content is 300 ppm or more, but its life is shortened slightly. In addition, if the moisture content level becomes burdened, the device may be decomposed and dried, and then manufactured, and such a dry state may prevent damage during continuous operation.

[Performance category]

(7) Carbon-based electrodes shall be capable of at least 100 charge / discharge cycles without damage due to wear of the carbonaceous material. Suitably, no damage should occur after more than 500 charge / discharge cycles, and the discharge capacity should be at least 150coulombs per gram of carbonaceous material of the electrode.

(8) Capacitive efficiency of carbonaceous electrode should be 70% or more, suitably 80% or more, and 90% or more is best.

(9) The low electrode made of carbonaceous material must overcome the overdischarge, and the charge capacity should be 70% or more even after 100 times of charge and discharge, and the charge capacity should be 80% or more even after 500 times or more. Should be good.

Therefore, the carbon-based electrode having the above-mentioned physical properties has the ability to discharge and recharge 100 times or more with a discharge capacity of 150coulombs or more per 1g of the carbonaceous material of the electrode, without any change in specifications (standard change of less than about 5%). More than 70% of the total efficiency will be.

In general, the carbonaceous material may be obtained by heating the preliminary material at a temperature of 850 ° C. until it becomes conductive. Carbonaceous preliminary starting materials that are capable of forming the electrically conductive carbonaceous material portion of the electrode are pitch (petroleum or collal), polyacetylene, polyacrylonitrile, polyphenyryl, saran (trademark) and the like. Elastomeric prestart materials should have some skeletal orientation. That is, most of these materials should have a concentrated orientated benzenoid structure or be able to be heated and converted to the same skeletal orientation or benzenoid on or near the surface. This is because the starting material has skeletal orientation.

Suitable carbonaceous preliminary materials that exhibit this skeletal orientation upon heating are assemblies of multiple or single filament strands of fibers prepared from petroleum pitch or polyacrylonitrile. Such multiple or single filament strands or fibers can be readily converted into yarns and made into a textile product. One technique for properly forming such monofilament fibers is described in US Pat. No. 4,005,183, wherein the fibers are made of yarn and woven into a fabric. The fabric is generally heated to a temperature of 1000 ° C., sufficiently carbonized to become an electrically conductive carbonaceous material and a material having the physical properties and properties described in (1) to (6) above. Such a fabric is suitable for use as an electrode of the secondary electrical energy accumulator of the present invention in connection with an electron collector.

The carbonaceous preparatory material is preferably in the form of continuous filament fibers or yarns or discontinuous fiber tows made of continuous filaments, and in particular formed into flat members such as woven, nonwoven or knit assemblies or man-made fibers, such as textiles, papers or felts. It is preferred that the assembly can be as layered as possible. However, it may be acceptable when yarns of short fibers 1 to 10 cm in length are woven into textile products (as short fibers having the desired physical properties described in (1) to (6) above in heat treatment). Of course, the preforms can be stably formed (as obtained by oxidation) in the desired form (such as knit, knit or felt) prior to carbonization, while these structures have a Young's modulus of 55,000,000 psi (380 GPa) or less. It should be less than 39,000,000 psi (269 GPa). It goes without saying that the carbonaceous material may be formed of a film preliminary material.

The degree of carbonization or graphitization does not act as a control factor for the material performance as an electrode element of the electrical accumulator, only the material is sufficient to be electrically conductive, and must also have the physical and mechanical properties mentioned above under the specified mode of use. Should be. The carbonaceous material about 90% carbonized is referred to in the literature as some carbon material and the carbonaceous material 91 to 98% carbonized is called carbonaceous material. On the other hand, more than 98% carbonaceous material is called graphitized material. It has been found that the carbonaceous material carbonized to 90 to 99% does not have the desired standard stability during electric charge and discharge and is not suitable as an electrode material. For example, RPG graphite, GRAFIOIL, etc., which have the necessary carbonization grade, conductivity and surface area, do not have the Young's modulus and the aspect ratio in the above-mentioned physical properties, and thus are unsuitable for electrode materials.

According to the present invention, a rechargeable and polarity inverting electrical accumulator is provided by disposing at least one pair of electrodes having the above-described carbonaceous material and an electronic current collector (which is electrically conductive) associated therewith. The housing has a non-conductive inner surface and is insensitive to moisture. The electrode is immersed in a nonaqueous solution (containing water of about 100 or less) in the housing. The solution itself must contain or be able to form a soluble metal salt that can be ionized. Each electrode is composed of an associated electronic current collector insulated from contact with the carbonaceous heat treatment material of the present invention and the electrolyte solution.

The secondary electrical energy accumulator of the present invention is composed of an electrically conductive carbonaceous fiber assembly, such as a fabric, and a metal, such as lithium or a metal alloy, as described above, so that the electrode can be precipitated in a non-aqueous solution and replaced with a cathode. It may consist of an electron collector of the positive electrode and without polarity inversion capability, and the solution itself may contain or form a soluble metal salt that can be at least ionized to provide electrolyte ions.

In the structure of a suitable embodiment of the secondary electrical energy storage device of the present invention, conventional fiberglass porous separators, polymers or composites of polymers and the like may be used to separate the positive and negative electrodes from each other. Most suitably, a nonwoven polypropylene sheet was used as the separator. This is because it has a desired degree of multiprocessing, which has a sufficient bend path to prevent the escape of carbonaceous fibers and thus prevent electrical shorts (porous separators are also used as lipid or rigid bodies for electrodes).

Electrical energy devices packaged in sealed housings are well known in the art. Such a housing may be implemented in the present invention as long as the housing material is electrically nonconductive or does not allow gas and moisture (moisture or vapor) to pass through.

Chemically usable materials for the housing materials include polyvinylchloride, polyethylene, polypropylene, polytrifluoroethylene and related perfluorinate polymers, instant polymer sets (ISPs), rapid curing urethane mixtures, aramids, eg Examples include DER 331 (registered trademark) or DERAKANE (registered trademark), ZETABON (registered trademark) and metal clads containing epoxy or non-conductive polymer such as glass or metal oxides. Propylene carbonate systems containing acrylic or polycarbonate and nylon are not suitable as housing materials. Propylene carbonate systems, including acyl or polycarbonate and nylon, are not suitable as housing materials. Acrylics and polycarbonates are extremely fragile and nylons (except aramids) are likely to react chemically.

The housing material shall provide a complete moisture barrier of less than 0.2 g H ₂ O / Y _Y / ft ² (2.15 grams of H ₂ O / Y _Y / m 2) which shields water vapor from the environment outside the housing. Currently known thermo plastics materials are useful thicknesses for battery housings and are incapable of independently blocking the above moisture. At present, for example, only metals such as aluminum or mild steel have no choice but to completely block moisture even with a thin thickness. Aluminum foil can prevent the passage of water vapor at a thickness of 0.038 mm or more. In addition, when thinned with other materials, a thin aluminum foil of 0.009 mm can adequately provide water vapor blocking. Suitable housings made of metallic plastic foil, CED-epoxy coated metal (negative electron deposition), plastic or metal with glass applied therein meet the demand for chemical and moisture barrier effects. Most batteries and accumulators on the market today are tested in dry boxes with levels below 5 ppm, or in double-walled housings with active molecules of 5A zeolite between the walls.

The electrolyte is preferably composed of a salt in which a salt which can be ionized in a solvent is dissolved or a non-conductive, chemically stable non-aqueous solvent for the ionization salt. Such composites may be used, for example, composites having oxygen, sulfur and nitrogen atoms which are generally known in the art, for example, bonded to carbon atoms in an electrochemically unreacted state. It is also possible to use nitriles such as acetonitrile, amides such as dimethylformamide, ethers such as tetrahydrofuran, sulfur complexes such as dimethyl sulfite and other complexes such as propylene carbonate. Of course, the solvent itself is ionized in use to supply the ions required for the solvent. Thus, some of the ionized salt must be dissolved or ionized when it is dissolved and proceeds into solution into the solvent or upon liquefaction. Some meltable salts may be used but the electrical charge and discharge rates may be adversely affected by the low concentration of these salts.

Some of the ionized salts that may be used in the present invention are sublimed in the present technology and include the following. For example, active bromide salts such as acali metal salts, suitably perchlorate (ClO ₄ =), tetra fluoroborate (BF ₄ =), hexafluoroarsenate (AsF ⁽ =), hexafluoroantimo Lithium, sodium or potassium or a mixture thereof containing a stable anion such as nate (SbF ⁽ =) or hexafluorophosphate (PF ₆ =)) may be used.

The electrolyte (solvent and salt) should be almost free of water, ie contain less than 100 ppm water, preferably less than 20 ppm water, more preferably less than 10 ppm water. Of course, the electrolyte may be dried, for example, having more than the required amount of water in the active zeolite 5A powder itself. Such agents can also be incorporated into finished batteries to maintain low water requirements. The electrolyte allows the ions (cations and anions) of the ionic salt to move freely through the solvent so that the electrical potential of charge and discharge moves ions to and from their respective poles (electrodes).

When made of fabric or sheet, the electrode includes a current collector that is electrically associated with at least one edge of the carbonaceous fiber or sheet. The edge is well protected as a material for insulating the current collector and protecting the current collector from contact with the fluid and its electrolytic ions. Of course the protective material should not be affected by fluid or electrolytic ions.

When the carbonaceous material is in the form of an assembly, such as a flat cloth, sheet or felt, the current collector is in close contact with the carbonaceous material of the electrode along at least one edge and preferably on all four edges. It is also contemplated that the electrodes may be made in other forms, such as fibers or threads, of cylindrical or tubular bundles having current collectors at the ends of the bundles. It is also evident that the plate-shaped cloth, sheet or felt-shaped electrode can be connected to the current collector by being rolled into the porous separator between the layers of carbonaceous material and the opposite edge of the curled material. Copper metal is used as the current collector, and any electrically conductive metal or alloy may be used, for example silver, gold, platinum, cobalt, palladium and alloys thereof. Similarly, when electrodeposition is used to bond metals or alloys to carbonaceous materials, the edges or ends of the electrodes, including most fiber ends, at the edges of the carbonaceous material are sufficiently large to provide a low resistive electrical contact and current path. As long as it is wet, other coating techniques (including melting) or electroless plating may be used.

Current collectors made of non-noble metals, such as copper, nickel, silver or alloys of such metals, must be protected from electrolytes and therefore synthetic resin materials or oxides which are not corroded by electrolytes and are not subject to significant degradation under the operating conditions of the battery, It is well coated as something like fluoride.

The electrode of the present invention made of an electrically conductive carbonaceous material and a current collector thereof can be used as the anode in the secondary energy tracking device. Repeated charging at a capacity of 150coulombs or more per 1g of activated carbonaceous material, and when the electrode is overdischarged to 80% of the total capacity at a fast or slow rate of charge discharge, the electrode itself or an electrolyte of solvent and ionic salt Little damage is observed.

Alternatively, the electrode of the present invention, which is made of an electrically conductive carbonaceous material and a current collector, may be used for both the positive electrode and the negative electrode in a secondary battery similar to the above-described operating characteristics.

The surface area of at least 0.5 m 2 per gram and the low resistivity of less than 0.05 ohm / cm of the carbonaceous material used for the electrode of the present invention is a desirable property. Therefore, the battery of the carbonaceous material electrode of the present invention has a very low internal resistance and a very high capacitance effect of usually 80% or more.

During the investigation period to limit the present invention, it has been found that the initial current density during charging of 100 to 200 mA / in ² (15.5 to 31 mA / cm 2) or more may damage the carbonaceous material of the electrode.

Example 1

A pair of electrodes, each having an area of 11 in ₂ (71 cm _s ), was heat-treated at a temperature of 1000 ° C. or higher by Panex® PWB-6 cloth (manufacturer manufactured by Stackple Fiber Co., Ltd. Prepared). The fabric was fabricated with a polyacrylonitrile (PAN) precursor material made of yarn from discrete filaments (artificial fibers) having an average length of about 2 inches (5 cm), a diameter of 7 to 8 micrometers, and an aspect ratio of about 700: 1. The fabric was then heat treated with a maker. In order to provide a current collector, the edges of the heat treated fabric were coated with copper as an electrodeposition method. Wires were soldered to one end of the copper-coated edge. All four edges of each electrode (current collector and wire connector) were coated with The Dow Chemical Company's amine curable epoxy resin, DER® 331, to protect the metal from the corrosive effects of the electrolyte in use. The electrode was immersed in an electrolyte solution containing a 15% LiClO ₄ solution in propylene carbonate contained in a polyvinyl chloride (PVC) housing. The electrode was made less than 0.25 inch (0.6 cm). Assembly of the electrodes into the housing was carried out in a dry box. The housing was sealed and the wires drooped out of the housing in the drying box.

The water content in the assembled housing was less than 10 ppm, the fibers had an Young's modulus of about 33,000,000 psi (230 GPa) and the ratio of area to weight was 0.6 to 1.0 m 2 / g. The charger capacity of the active carbonaceous material of the electrode was determined to be about 250 coulomb / g.

The cell prepared as above was electrically charged at a maximum voltage of 5.3 volts with a current not exceeding an electrode area of 35 mA (5.4 milliamps / cm 2) per inch ² .

The cell was charged and discharged 1250 times over 11 months, exhibiting a capacitive effect of more than 90%, and performed at a discharge capacity of more than 85%. At this time, the battery was disassembled and the fibers were observed under a microscope at 1000 times magnification from each of the cloth electrodes. As far as measurable, the fibers had the same diameter as the fibers of the same lot that were not used in the cell. The cell was reassembled and tested continuously in the same manner as described above. The cell underwent 2800 charge and discharge cycles over 23 months without a reduction in the capacitive effect, and continued to have a 90% total effect.

Example 2

Six electrodes similar to those of Example 1 were prepared and connected to three battery units such that each pair of electrodes was sealed in a separate polyethylene pocket (bag). Connect the electrodes in series Three battery units were operated in the same manner as in Example 1 except that the voltage was about 16 volts. The initial open circuit voltage was about 13.5 volts. After 228 electrical charges and discharges, the discharge was performed over 78% of the total capacity and overdischarge, and the cell was disassembled to remove the electrode from the pocket and to investigate the signs of degradation, ie, flaking of fibers, excessive expansion and contraction. Upon investigation it was not used to prepare the electrodes of this example. No significant change in fiber diameter was found with the fibers measured in the same lot of fabric. The measurement was performed with a laser interferometer.

Example 3

Several plate-shaped sheets were cut out of a woven fabric made from a petroleum pitch and made from an essential continuous single filament precursor fiber. The fibers are manufactured by Union Carbide Company and marketed as Doornell®. A cloth was woven from a short yarn of precursor fiber having an aspect ratio of about 800: 1 and heat treated at a temperature of 2000 ° C. or higher. Each of the plate-shaped sheets has an area of about 1 ft ² (930 cm ² ). The fiber has a Young's modulus of 45,000,000 psi (351 GPa) and a surface area of about 1 m 2 / gm after heat treatment. The sheet is coated with copper metal along its four edges so that all the fibers are electrically connected to form the current collector frame. An insulated copper wire was attached by soldering to one edge of the current collector near the corner and coated with Derakan (trade name of The Dow Chemical Company) of curable vinyl ester resin. Each pair of sheets is aligned parallel to each other with the soldered lines at opposite ends of the mating edges and separated into 5 millimeter (0.1 mm) thick porous, nonwoven fibrous polypropylene composition sheets.

Polyethylene pockets (bags) of about 1 ft ² (930 cm ² ) were used as battery containers. The three cells were assembled in a dry box by placing a pair of carbon fiber sheets and their separators in three pockets each and 500 g of an electrolyte of 15 weight percent LiClO ₄ solution in polypropylene carbonate in each pocket. The electrolyte level in the pocket was determined to provide 21 g of active fiber per electrode (area of electrode exposed to electrolyte). The remainder of the carbon fiber of each electrode was either from solution or covered with a Deracan® resin / copper frame.

The battery assembly in the dry box maintained a water capacity of less than 20 ppm of the electrolytic solution. Each pocket is sealed in a dry box, such that the welded wire ends exit through the seal at opposite ends of the sealed edges. A jar of active zeolite 5A parental body (to absorb moisture) was added on top of the cell and the assembly was removed from the dry box. The two end plates of the battery connected the end lines to the terminal through the lid or the lid for the box, and the lid was urgently sealed in the box.

The assembly was charged for 45 minutes at 15-16 volts potential and a current of 1.8 to 2 amps. The device was then discharged through a 12 volt automotive headlight drawing an average current of 2.0 to 2.5 amps. The device was discharged at 90% of its capacity for 30 minutes. The electrical, charge and discharge cycles were performed 850 times. At this time, the cell was disassembled and the fiber was examined as a microscope at 1000 times magnification, and no sign of deterioration or expansion by flaking was found. The device passed electrical charging and overdischarge at 90% of its capacity during each cycle.

Example 4

PAN main ingredient (precursor fiber) cloth was obtained from R.K. textile company of Hitton Moore United Kingdom. The cloth is commercially available from Panox®, and is a non-conductive carbon fiber woven from a cloth having an aspect ratio of 250: 1 or more and is not heated to a temperature of 400 ° C or more. The fabric was heat treated at a temperature of about 1000 ° C. for a sufficient time to give the fabric electrical conductivity. The heat treated fabric has a Young's modulus of 23,000,000 psi (160 GPa) and a surface area of about 1 m 2 / gm. Two sample fabrics of 2 person (5 cm) in width and 4 in ² (26 cm 2) in area are cut out from the heat treated fabric, and the four edges of each fabric are made of copper metal to form a current collector for the electrode. Coated A wire was soldered to one corner of the current collector of each electrode. The braze and copper current collectors were coated with a Deracan® vinyl ester resin coating composition. A nonwoven polypropylene composition sheet, Celgard® 5511, is placed between the two electrodes and the electrode is placed in a plastic pocket (enclosed body). This assembly was placed in a dry box at which the water content was kept below 20 ppm of the electrolyte. A 10 wt.% Solution of LiClO _{4 in} propylene carbonate solution was used to fill the enclosure until both electrodes were immersed in the electrolyte.

The leads from each electrode are connected to a dipole twin-two switch where one terminal is connected to an 5.3 volt electrical voltage source. The other terminal is connected to a 10 ohm electrical resistive load. The battery discharges at least 80% of the total charge and operates at least 800 times of electrical charge and discharge with a capacity efficiency of 80% or more. This battery capacity is about 70% of the capacity of the PAN experiment (Example 1) at the charge of the charging electrode.

It has been found that the battery constructed by the present invention has an internal resistance of not more than 0.41 ohm / m ² (0.038 ohm / ft ² ) of the electrode surface area of the six-pole battery. Initially measured below 1 ohm, this value was measured including the leads connected to a discharge system about 6 m long. When the resistance of the lead wire was measured and the resistance from the battery to the system was re-measured, the resistance of the battery (second battery) was measured to 0.41 ohm / m 2 (0.038 ohm / ft ² ).

The data of the experiment was confirmed by the highway experimenter, and the two-electrode terminals were made of "Thronel" and VCB-45 fabrics having a Young's modulus of 315 GPa (45 million psi), a surface area of 1 m2 / g, and an aspect ratio of 10,000 or more. Each cloth has a size of 15.2 cm x 15.2 cm. The copper edges plate all four edges of the fabric to form a current collector. Thus, the current collector is covered with DERAKANE® 470-36. The edge of the current collector has a width of about 2.6 cm leaving about 10 cm x 10 cm of active carbonaceous material area. The 100 cm 2 area of each electrode contains about 6 g of carbon fiber. The electrodes were separated by placing one electrode in a heat-sealed bag of "Celgard®" 5511 microporous polypropylene membrane.

The assembly of the electrode and separator is placed in a polyethylene bag, filled with 15% by weight of a dry electrolyte of LiClO ₄ in propylene carbonate (about 100 cc), the assembly containing two plastics supporting the sides of the bag containing the electrolyte. It is pressed between the edge platens. The thickness of the DERAKANE-coated copper current collector is maintained at the initial separation distance from each other by compressing the fiber sections of the two electrodes. Finally, a 10 cm × 10 cm spacer is inserted into the corner pressing pin to join the electrode-separator combination more firmly together. This drops the battery resistance from about 0.9 ohms to about 0.7 ohms.

Discharge data for various discharge rates were obtained with the two batteries of the shapes mentioned above. In the case of a 0.9 ohm cell, the current collector was limited to about 4 mm epoxy coating. In the case of a 0.7 ohm cell, the electrode was pressurized with a perforated polypropylene separation between the two electrodes (about 1 mm or less) at about the center.

In the graph of the figure, curve I shows the terminal voltage discharge amount (coulomb / gm) of a 0.9 ohm cell at various discharge rates from 6 hours to 3/4 hours. This discharge amount corresponds to the so-called first frato (2 volt blocking). Assuming that the total capacity of the first plateau is 180 coulomb / gm with respect to the secondary cut-off voltage, the value on the graph can be replaced with "% discharge" and "180 coulomb / gm" corresponds to "100% discharge".

At some loads, the total energy recovered over three hours is approximately equal to the energy over six hours. It is ineffective at a fast 3/4 hour discharge due to cell resistance and polarization of the electrodes. The electrode current density with respect to this discharge amount is as follows.

Rate (hours) Average current density at constant load (ma / cm 2)

6 0.5

13 1.0

1.5 2.0

0.75 4.2

1 coulomb / gm is based on the weight of activated carbonaceous material at one electrode. Curve (III) is from 0.7 ohm cell. Clearly, low resistance electricity can use more energy. Curve III compares two cells at high discharge rate (3/4 hour ratio).

A lithium metal reference electrode is inserted into the cell to determine that the electrode is polarized. The voltage drop between each electrode and the reference electrode is determined by opening the circuit during charging and discharging.

When the circuit is opened, the voltage between the electrode and the reference electrode is less than 100 mv and is charged instantaneously. When measured between the + and reference electrodes, the voltage changes instantaneously, decreases after each charge, and decreases after each discharge.

The maximum power capacity of the batteries at different stages of charging was determined by + discharging the cells at the load giving the terminal voltage of the open circuit voltage. "+" Was for 10 seconds and power was measured as the average power for 10 seconds.

The cell was first charged to 344coulomb / gm of activated carbonaceous material on one electrode. It was treated as 100% charged. The maximum current obtained from a 10 cm x 10 cm electrode cell at 100% state of charge was 2.5 to 3.0 A. After that, power determinations were made at values of 247 coulomb / gm (75% charge) and 224 coulomb / gm (65%). Curve V shows the result.

The maximum power from this cell was about 0.48 w / gm of fiber at 100% charge and dropped to about 0.31 w / gm of fiber at 75% charge. After that, the voltage drops and polarization takes place, so the power capacity drops quickly. Positive discharges of more than 10 seconds do not sufficiently reduce the final power. Curve VI is the voltage trajectory of the maximum power discharge for 40 seconds. After the first 10 seconds, the voltage drop is small.

Example 5

The tri-battery battery consisted of 12 plates in total, 4 plates per cell of the Thormel brand fiber shown in Example 3. Each plate is 25.5 cm x 25.5 cm (12 in x 12 in) and each edge is copper plated. Soft copper plating is coated with the Derakane® brand of curable vinyl ester resins. The plate has a reaction area of about 852 cm ² (132 in ² ). Four plates of each cell were assembled with perforated polypropylene scrim separators between each plate. The pairs of plates of each battery are connected in parallel so that the plates are alternately +,-, +, and-during charging and discharging. Four plates and each separator are placed in a polypropylene bag, which is 33 cm x 33 cm (13 in x 13 in) and filled with 600 cc of 15 wt% LiClO ₄ electrolyte in propylene carbonate. The electrolyte in each bag is sufficient to provide about 37 gm of active fibers per electrode plate.

The battery was initially charged for 1000 minutes to a capacity of 1.9 A hours at a potential of 14 to 16 volts. The battery then discharges an average capacitance of 6.2 A hours through a 12 volt automotive headlight for 200 minutes, resulting in more than 80% discharge. Recharging was carried out for 800 minutes, and the average total efficiency of the charge discharge cycle was found to be about 90%.

Claims (22)

An electrode for secondary electrical energy accumulators, the electrode body having an electrically conductive carbonaceous material having a skeletal orientation on its surface or its vicinity, and an electrode having a current collector, wherein the Young's modulus of the carbonaceous material is 1,000,000 psi ( 6.9 GPa) or more, and the electrode is characterized in that the physical specification variation is 5% or less during repeated electric charging and discharging. The electrode of claim 1, wherein the Young's modulus of the carbonaceous material assembly is between 1,000,000 psi and 55,000,000 psi (6.9 GPa to 380 GPa), and is produced from a preliminary material selected from pliacroronitrile or pitch. The electrode according to claim 2, wherein the elastic modulus of elasticity of the carbonaceous material is 1,000,000 psi to 55,000,000 psi (6.9 GPa to 380 GPa). The electrode according to claim 2, wherein the elastic modulus of elasticity of the carbonaceous material is 20,000,000 psi to 45,000,000 psi (138 GPA to 211 GPA). The electrode according to any one of claims 1 to 4, wherein the surface area of the carbonaceous material is 0.1 to 50 m 2 / g. The electrode of claim 5, wherein the surface area of the carbonaceous material is 0.1 to 10 m 2 / g. The electrode according to claim 5, wherein the surface area of the carbonaceous material is 0.1 to 6 m 2 / g. The electrode according to claim 1, wherein an assortment ratio (1 / d) or an equivalent ratio of the carbonaceous material is 100: 1 or more. The electrode according to claim 1, wherein the carbonaceous material has a structure of 6.45 cm 2 to 930 cm 2 or more. The electrode of claim 1, wherein the carbonaceous material is in the form of a fabric, film, feeder or felt flat sheet or assembly thereof. The electrode of claim 1, wherein the carbonaceous material is in the form of a woven or felt fabric or sheet having an assembly of artificial fibers or continuous filament yarn of 1 to 10 cm in length. The electrode according to claim 1, wherein the carbonaceous material is a knitted or knitted fabric made of an assembly of 1 to 10 cm long artificial fibers or continuous filament yarns. The electrode according to claim 1, wherein the carbonaceous material is a fabric or felt fabric or sheet of an assembly of artificial fibers or continuous filament yarn. The method of claim 1, wherein the electron collector is an electrically conductive metal flattened on at least one edge of the carbonaceous material, wherein the flattened edge is coated with a protective material exhibiting non-conductive or non-reactance. Electrode. The electrode of claim 1, wherein the carbonaceous material is capable of maintaining a total efficiency of 70% or more without damaging the structure of the material during 100 or more electrical discharges in an overdischarge state of 70% or more. A secondary electrical energy accumulator comprising a housing having an electrically nonconductive inner surface and a moisture impermeable outer surface or a thin film body, and having at least one cell disposed in the housing, wherein each cell is electrically connected from contact with each other. Wherein the housing contains a non-aqueous electrolyte, wherein at least one electrode of each cell is an electrode as claimed in any one of claims 1-15. Secondary electrical energy storage device characterized in that. 17. The secondary electrical energy accumulator according to claim 16, wherein the electrolyte solution contains a non-conductive, chemically stable non-aqueous solvent and a dissolved ionization salt. 18. The secondary electric machine according to claim 16 or 17, wherein the electrolyte solvent is selected from a complex having oxygen, sulfur and nitrogen atoms bonded to carbon atoms in an electrochemically unreacted state, wherein the salt is an alkali metal. Energy accumulator. 19. The secondary electrical energy storage device according to claim 18, wherein the electrolyte solvent is propylene carbonate and the alkali metal salt is lithium perchlorate. In a secondary electrical energy accumulator comprising a housing having an electrically nonconductive inner surface and a moisture impermeable outer surface or a thin film body, the secondary electrical energy accumulator having at least one cell disposed in the housing, wherein each cell is electrically connected from contact with each other. A pair of insulated battery conductive electrodes, wherein said housing contains a non-aqueous electrolyte, wherein each electrode of each battery is an electrode as claimed in any of claims 1-15. Secondary electrical energy storage device characterized in that. 21. The secondary electrical energy storage device according to claim 20, wherein each electrode of the battery is free to select polarity upon recharging and that some or all of the electrodes can be reversed in polarity without damage. 22. The secondary electrical energy storage device of claim 20 or 21, having a maximum power density of at least 0.31 watts per gram of activated carbon anode for a 40 second pulse period upon full charge.

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