Electrical energy storage device

Abstract

This invention relates to an electrical energy storage device comprising: high surface area fibers (e.g., fibers and / or microfibers with a shape) coated with carbon (graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, CNTs, or graphite-coated CNTs); an electrolyte; and / or an electrode active material (e.g., lead oxide) located in an electrode. The electrode is used to form an electrical storage device such as an electrochemical cell, an electrochemical double-layer capacitor, or an asymmetric capacitor.

Description

[0001] This application is a divisional application of the invention patent application filed on November 18, 2009, with application number 201610006277.4, entitled "Electric Energy Storage Device". Furthermore, the invention patent application filed on November 18, 2009, with application number 201610006277.4, entitled "Electric Energy Storage Device", is a divisional application of the invention patent application filed on November 18, 2009, with international application number PCT / US2009 / 064992 and national application number 200980146053.1, entitled "Electric Power Storage Device".

[0002] Related applications

[0003] This application claims priority to U.S. Provisional Application No. 61 / 115,815, filed November 18, 2008, and U.S. Provisional Application No. 61 / 150,987, filed February 9, 2009, both of which are incorporated herein by reference. Technical Field

[0004] This invention relates to the use of fibers (e.g., capillary fibers) in electrochemical cells, electrochemical double-layer capacitors, and asymmetric capacitors. Background Technology

[0005] Electrical energy storage devices, such as electrochemical batteries and capacitors, are known to be used in vehicles such as automobiles. For example, lead-acid batteries are already used in start-up, ignition, and spark-ignition (SLI) applications.

[0006] The two most common electrical energy storage devices are batteries and capacitors. Conventional lead-acid battery electrodes are formed by producing a lead paste that can also be used as a substrate (e.g., a grid, plate, or wire mesh) applied to it. As the lead paste dries, openings form within it where the battery electrolyte can enter, increasing the grid's reaction area and its charge capacity. However, excessive porosity reduces the electrode's structural integrity. Furthermore, due to the limited porosity of conventional electrodes, a significant amount of active material cannot access the electrolyte and is underutilized or essentially wasted because it is unusable for the reaction. Typically, about half of the lead in a conventional lead-acid electrode is unusable or unused. Throughout its lifespan, the battery undergoes multiple charge-discharge cycles, which also degrades the electrode due to repeated reverse reduction-oxidation reactions with the supplied current. Over time, a portion of the electrode may become electrically disconnected from the rest. The structural integrity of the electrode also deteriorates over time. To hold the electrode material in place, a scrim layer (e.g., a fibrous mesh) can be used. A veil can be placed on the charge collector before applying the active material paste and / or placed on the paste after applying the active material adhesive. The veil can help hold the electrodes together, but it does not improve porosity or increase reactivity.

[0007] A capacitor stores energy in the form of an electric field between two conductors. Typical capacitors use stacks of thin plates (alternating capacitor plates and dielectric) or rolls of thin sheets (alternating capacitor and dielectric sheets rolled together). Energy is typically stored as charges of equal magnitude and opposite polarity in adjacent plates or sheets separated by a dielectric material. In a typical capacitor, current flows from the capacitor surface through the entire capacitor plates, requiring the plates to be conductive to reduce resistance losses and thick enough not to overheat and melt. Such requirements impose undesirable limitations on the energy storage-to-weight ratio of a capacitor. Capacitance (i.e., the amount of charge stored on each plate) is directly proportional to the surface area of ​​the plates and inversely proportional to the distance between the plates. Therefore, increasing the energy storage capacity of a capacitor typically requires increasing the plate size and / or decreasing the distance between the plates. However, increasing the plate size increases resistance and overheating problems, while decreasing the plate spacing increases the risk of charge passing directly between the plates (i.e., short-circuiting), burning them out and rendering the capacitor unable to retain charge.

[0008] Electrochemical double-layer capacitors (“EDLCs”) are energy storage devices capable of storing more energy per unit weight and per unit volume than conventional electrostatic capacitors. Furthermore, EDLCs are typically able to transfer the stored energy at a higher power rating than conventional rechargeable batteries. Conventional EDLCs use carbon as the active material in the electrodes. A conventional EDLC comprises two porous electrodes isolated from electrical contact by a porous separator. Both the separator and the electrodes are immersed in an electrolyte solution. This allows ionic current to flow between the electrodes through the separator but prevents current short-circuiting of the battery. A current-collecting grid is coupled to the back of each electrode. EDLCs store electrostatic energy in a polarized liquid layer formed when a potential exists between the two electrodes immersed in the electrolyte. When a potential is applied across the electrodes, a double layer of positive and negative charges forms at the electrode-electrolyte interface due to the polarization of electrolyte ions by the polarization of electrolyte ions, resulting from charge separation under the applied electric field and also due to the bipolar orientation and arrangement of electrolyte molecules across the entire surface of the electrodes. No reduction-oxidation reaction is involved in the charge storage mechanism.

[0009] Asymmetric electrochemical capacitors use a cell electrode as one of the electrodes. This cell electrode has a large capacity compared to a carbon electrode, making its voltage not significantly change with charge. This allows for a higher overall cell voltage. Examples of asymmetric capacitor materials include PbO2 (containing carbon) and NiOOH (containing carbon).

[0010] Overview of basic and other advantageous features

[0011] There is a significant need for electrical energy storage devices with greater energy storage capacity, reduced weight, and / or improved recyclability. It is desirable to provide an energy storage device, such as that disclosed in this application, comprising one or more of these or other advantageous features, including batteries, capacitors, asymmetric capacitors, etc.

[0012] 1. Electrodes used in energy storage devices have increased permeability without reducing the overall structural integrity;

[0013] 2. Electrodes used in energy storage devices exhibit increased structural integrity without reducing magnetic permeability;

[0014] 3. Energy storage devices that use fewer active materials without reducing energy capacity;

[0015] 4. Energy storage devices, including electrodes used as electrodes to store energy in electrochemical cells and capacitors;

[0016] 5. Energy storage devices with a higher energy-to-size ratio than conventional energy storage devices; Summary of the Invention

[0017] An exemplary embodiment relates to an energy storage device including at least one positive electrode, at least one negative electrode, and at least one partition separating the positive electrode from the negative electrode, wherein at least one of the at least one negative electrode or at least one positive electrode comprises fibers with a high specific surface area.

[0018] Another exemplary embodiment relates to an electrode comprising a charge collector grid, an electrode active material coated on the charge collector grid, and fibers with a high specific surface area.

[0019] Another exemplary embodiment relates to an electrode comprising a charge collector comprising a felt made of fibers with a high specific surface area and an electrode active material coated on the felt.

[0020] These and other features and advantages of the various embodiments of the systems and methods according to the invention are described in the following detailed description of various exemplary embodiments of the various devices, structures and / or methods according to the invention, and these features and advantages will become apparent from the detailed description. Attached Figure Description

[0021] Exemplary embodiments of the systems and methods according to this disclosure will be described in detail with reference to the accompanying drawings, in which:

[0022] Figure 1 This is a perspective view of a vehicle including a battery module according to an exemplary embodiment;

[0023] Figure 2 This is an exploded cross-sectional view of a battery module according to an exemplary embodiment;

[0024] Figure 3 This is a cross-sectional view of an exemplary embodiment of the trilobal fiber according to the present invention;

[0025] Figure 4 This is a cross-sectional view of a four-lobed fiber according to an exemplary embodiment;

[0026] Figure 5 This is a cross-sectional view of a circular fiber according to an exemplary embodiment;

[0027] Figure 6 This is a cross-sectional view of a trilobal fiber loaded with carbon and coated with battery electrode active material according to an exemplary embodiment;

[0028] Figure 7 This is a partial perspective view of an electrode having a felt capillary fiber according to a first exemplary embodiment;

[0029] Figure 8This is a cross-sectional view of a trilobal fiber loaded with carbon and electrolyte and coated in a battery electrode active material according to a second exemplary embodiment;

[0030] Figure 9 This is a cross-sectional view of a fiber having an electrode active material coated on the interior of the fiber and permeated with an electrolyte, according to an exemplary embodiment.

[0031] Figure 10 It is used according to the exemplary embodiments. Figure 9 A front view of the fiber-based dual electrochemical cell and EDLC of the embodiment;

[0032] Figure 11A This is a front view of the solar panel grid according to an exemplary embodiment;

[0033] Figure 11B It is covered by high specific surface area fibers according to an exemplary embodiment. Figure 11A A front view of the solar panel grid;

[0034] Figure 11C It is covered by electrode active material according to an exemplary embodiment. Figure 11B A front view of the solar panel grid;

[0035] Figure 12A This is a cross-sectional view of a fiber with a shape coated with an electrode active material according to an exemplary embodiment;

[0036] Figure 12B According to an exemplary embodiment, it is coated with a permeable insulator. Figure 12A A cross-sectional view of the fiber;

[0037] Figure 12C According to the exemplary embodiments, by Figure 12B A perspective view of felt made of fibers;

[0038] Figure 13 This is an end view of a dual-component filament according to a first exemplary embodiment;

[0039] Figure 14 This is a perspective view of a dual-component filament according to a second exemplary embodiment;

[0040] Figure 15 This is a perspective view of a dual-component filament according to a third exemplary embodiment;

[0041] Figure 16 This is a side view of a dual-component filament according to a fourth exemplary embodiment; and

[0042] Figure 17 This is a side view of a dual-component filament according to a fifth exemplary embodiment.

[0043] It should be understood that the accompanying drawings are not necessarily drawn to scale. In some instances, details that are not necessary for understanding the invention or that make other details difficult to understand have been omitted. It should also be understood that the invention is not limited to the specific embodiments described herein. Detailed Implementation

[0044] refer to Figure 1 The vehicle 160 shown includes an electric energy storage device 100 according to an exemplary embodiment. Although the vehicle 160 is shown as an automobile, according to various alternative embodiments, the vehicle may include various types of vehicles, including automobiles, buses, recreational vehicles, ships, etc. According to an exemplary embodiment, the vehicle 160 uses an internal combustion engine (not shown) for locomotive purposes.

[0045] Figure 1 The illustrated energy storage device 100 is configured to provide at least a portion of the energy required to start or operate the vehicle 160 and / or various vehicle systems (e.g., start, ignition, and spark-ignition (SLI) systems). Furthermore, it should be understood that the energy storage device 100 can be utilized in various applications not involving a vehicle, and all such applications are intended to be within the scope of this disclosure.

[0046] Figure 2 An electric energy storage device 100 according to an exemplary embodiment is shown. In various embodiments, the electric energy storage device 100 includes several battery elements disposed in separate compartments containing an electrolyte container or housing 110. Figure 2 The embodiments relate to automotive applications, wherein groups of 12-16 plates 104 and 105 are used in each of six stacks 107 to generate a standard automotive 12-volt battery. It will be apparent to those skilled in the art, upon reading this specification, that the size and number of individual plates 104 and 105, the size and number of plates 104 and 105 in any particular stack 107, and the number of stacks 107 used to construct the energy storage device 100 can vary widely depending on the desired end use.

[0047] In various embodiments, the housing 110 includes a box-like base or container and is at least partially made of moldable resin. Multiple stacks 107 or plates are connected in series according to the capacity of the electrical energy storage device and are housed together with an electrolyte, typically aqueous sulfuric acid, within the container or housing 110.

[0048] In various embodiments, the energy storage device 100 includes compartments having a front wall, end walls, a rear wall, and a bottom wall. In various embodiments, five battery dividers or partitions are disposed between the end walls, creating six compartments, a feature typically found in 12-volt automotive batteries. In other embodiments, the number of dividers and compartments can be varied to create energy storage devices with different voltages. In various embodiments, a plate group or stack 107 is located in each compartment, each plate group or stack 107 including one or more positive plates 104 and negative plates 105, each plate having at least one handle 103 and a partition 106 placed or disposed between each positive plate 104 and negative plate 105. In various exemplary embodiments, the positive plate 104 and negative plate 105 include grids 101 and 102 with attached handles 103, the grids 101 and 102 being coated with a positive electrode active material or a negative electrode active material or paste, respectively.

[0049] A cover 111 is provided for the housing 110, and in various embodiments, the cover 111 includes a terminal bushing and a filling tube to allow electrolyte to be added to the battery and to allow for servicing. To prevent undesirable leakage of electrolyte from the filling tube and to allow the release of gases generated during the electrochemical reaction, the energy storage device may also include one or more filler orifice caps and / or vent cap assemblies.

[0050] At least one positive terminal post 108 and a negative terminal post 109 may be found on or around the top or front compartment of the energy storage device. Depending on the design of the energy storage device, such terminal posts 108 and 109 typically include portions that can extend through the front of the cover 111 and / or housing 110. In various embodiments, terminal posts 108 and 109 also extend through a terminal post sealing assembly (not shown) to help prevent acid leakage. It should be appreciated that various terminal arrangements are possible, including top, side, or corner configurations known in the art.

[0051] Figure 2 Also shown is a conventional cast connector 112 comprising a rectangular elongated body portion having a length sufficient for each handle in the electrical coupling plate assembly, and an upwardly extending portion having rounded corners. Figure 2 The cast-fit connector handle for coupling to the negative terminal post is also shown. (See diagram.) Figure 2 As shown, according to various embodiments, the cast connector includes the main body portion of each handle in the coupling end compartment and a post formed therewith to protrude through the cover.

[0052] Each battery element or segment includes at least one positive plate 104, at least one negative plate 105, and a separator 106 located between each positive plate 104 and negative plate 105. The separator 106 is disposed between the plates to prevent short circuits and unwanted electron flows during reactions in the energy storage device 100.

[0053] As mentioned above, the reactivity of conventional solar panels or electrodes increases with increasing porosity (related to the amount of vacant space). However, the structural integrity or strength, as well as the internal conductivity, of conventional electrodes decreases with increasing porosity. Furthermore, the structural strength and internal conductivity of conventional electrodes tend to deteriorate with battery discharge and recharge time.

[0054] The plates or electrodes described herein have greater porosity and / or structural integrity than conventional electrodes. In various exemplary embodiments, small, high specific surface area fibers (e.g., fibers and / or microfibers with a specific shape) capable of transporting electrolyte solution via capillary action are incorporated into various components or portions of the electrode, or otherwise utilized together with various components or portions of the electrode. These high specific surface area fibers can reinforce the electrode and / or create pathways for the electrolyte to better permeate the electrode active material. The resulting electrodes require less active material to generate the same current and retain their charge capacity through more discharge-recharge cycles than conventional electrodes. They also better maintain their structural integrity and / or internal conductivity. In various exemplary embodiments, non-capillary conductive fibers can also be used to reinforce the electrode active material and increase internal electrode conductivity.

[0055] In various exemplary embodiments, the disclosed electrodes can also be used in electrochemical double-layer capacitors (“EDLCs”). Capacitance is enhanced by incorporating various forms of carbon, such as graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, and carbon nanotubes (CNTs), or any combination of these materials. Carbon can be incorporated into capillary fibers (e.g., coated or infused) and / or mixed with active materials. Adding carbon to the fibers helps increase their effective surface area and conductivity. Conductive fibers help prevent a portion of the electrode from becoming electrically isolated (e.g., by physical and / or conductive disconnection of a portion of the electrode and / or by the formation of a poor conductor within the electrode). It should be understood that the term “electrode” as used herein refers to a device for storing charge in an electrochemical cell cell, EDLC, and / or asymmetric capacitor (e.g., a dual-cell / EDLC).

[0056] In various exemplary embodiments, the disclosed energy storage device includes an asymmetric capacitor. An asymmetric capacitor is an electrochemical capacitor in which one plate is replaced by a battery electrode. In various exemplary embodiments, the electrodes in the disclosed energy storage device store charge as both electrochemical battery electrodes and electrochemical capacitor electrodes.

[0057] As an example, Figure 3-5 Three fiber shapes within the scope of this invention are shown. Figure 3 An exemplary embodiment of the trilobal fiber 241 is shown. Figure 4 An exemplary embodiment of the four-leaf shaped fiber 242 is shown. Figure 5 An exemplary embodiment of the circular fiber 243 is shown. These and other shapes have the ability to retain the material coated therein without the use or need of adhesives. Other fiber shapes now known or to be studied in the future may also be used.

[0058] In various exemplary embodiments, depending on the processing method, the fiber has a cross-sectional diameter of about 1 micrometer to about 100 micrometers and a length of 0.02-20 mm. The manufacture of capillary fibers with high specific surface area is known. For example, Largman et al. (US 5,057,368) solved the manufacture of trefoil and tetralobed fibers, the entirety of which is disclosed and incorporated herein by reference.

[0059] Individual fibers can be straight or non-straight. Non-straight fibers can have one or more shapes, such as, but not limited to, coiled fibers, looped fibers, crimped fibers, and air-jet interlocked fibers. These are provided by way of example, and individual fibers can have one or more of these or other forms of cross-section.

[0060] In various exemplary embodiments, the fibers are formed from polymers (e.g., polyester, polypropylene, polyethylene, and / or polyethylene terephthalate). The polymer may be used in conjunction with additional materials (e.g., carbon, metals, and metal oxides) before or after fiber formation. The fibers can be formed from a variety of organic and / or inorganic materials, including, for example, polypropylene, polyethylene, polyethylene terephthalate (PET), and / or glass. The fibers may also be formed from conductive polymers (e.g., redox polymers) that, depending on their configuration, can be used as type I, II, or III capacitors. The choice of materials may be influenced by the environment in which they are placed or utilized (e.g., materials resistant to the corrosive effects of acids used in batteries). Fibers may be formed in a single step or multiple steps to provide different material layers with various mechanical, chemical, electrical, and / or "fluid" transport properties. The capillary behavior of the fibers can be tuned or modified by selecting hydrophilic or hydrophobic fiber materials.

[0061] In various exemplary embodiments, the fibers may be used in their "prototype," carbonized, and / or preloaded form with engineered materials (e.g., metals, carbon black, silicon, tin oxides, graphite, and / or acids). In various exemplary embodiments, the fibers are pretreated using various methods and / or approaches. The preloaded materials may include nanoscale materials, such as nanofibers and multi-walled nanotubes. Coatings may be applied by any suitable method, such as by deposition via diffusion and solvents in slurry form (e.g., by water, acid, or other solvents), by spraying, or by immersion in the fibers (e.g., in a conductive metal). For example, many materials that can be used to make fibers have higher melting points than lead-based electrode active materials. Thus, lead-based active materials can be applied to the fibers by immersing them in molten active material and allowing the active material to harden, solidify, and / or in other forms related to the fibers.

[0062] In various exemplary embodiments, the EDLC is integrated with an electrochemical battery (e.g., a lead-acid or lithium-ion battery). In various embodiments, the battery electrode also serves as the EDLC electrode. The electrode may include a battery electrode active material and carbon. In various embodiments, the electrolyte contains sufficient ions to chemically react with the battery active material and form a charged layer for the EDLC.

[0063] The fibers can be made of various materials, including conductive and / or dielectric materials. In various embodiments, the fibers are made of two or more materials (e.g., a conductive core and a dielectric surface). The fibers may be conductive in or within their core (e.g., internally) and non-conductive on or outside their surface, which would allow the core to be, or serve as, a current collector for a capacitor formed of a dielectric material. This can be achieved at least in part by, for example, coextruding the fibers or by coating the conductive fibers with a dielectric.

[0064] like Figure 6 As shown, in various exemplary embodiments, the exemplary trefoil fiber 241 is coated or loaded with carbon additive 245 (e.g., graphite, expanded graphite, activated carbon, carbon black, carbon nanotubes, and / or CNTs). Carbon materials can be loaded into regions or surfaces of the fiber in their original form (i.e., without any binder material) or in a combined form, in which a known amount of binder is added to the carbon to form a stable porous composite (e.g., within the fiber). CNTs, carbon nanofibers, and carbon whiskers can be grown on various substrates. One method of achieving this is disclosed in International Patent Application No. PCT / US2007 / 011577, the entire contents of which are incorporated herein by reference.

[0065] In each exemplary embodiment, such as Figure 6As shown, fiber 241 (e.g., inner surface) is coated with carbon and surrounded by electrode active material (e.g., coated on or mixed with the fiber).

[0066] In each exemplary embodiment, such as Figure 7 As shown, capillary fibers are disposed or otherwise formed into a felt 222 (e.g., woven, non-woven, or dot-bonded). In various embodiments, an active material 223 (e.g., lead oxide) is disposed (e.g., coated) on the felt 222 to form an electrode 220 for an electrical energy storage device (e.g., an electrochemical cell). In various embodiments, as Figure 6 As shown, the fibers may also be coated with carbon (e.g., graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, and / or CNTs), and in some embodiments, the fibers are used as EDLCs. Such embodiments can help increase lifetime, generate a high interfacial area thereby increasing the bilayer capacitance of the active electrode, help optimize charge acceptance and / or high-speed discharge, and / or improve the conversion efficiency (e.g., initial charge) of the active material.

[0067] In each exemplary embodiment, except or instead Figure 7 The longer fibers shown are dispersed, mixed, or otherwise arranged with the active material as short fiber sheets. The mixture of short fiber sheets and active material can be arranged on conventional charge collectors (e.g., grids, plates, or wire mesh) or on fiber felts. In various exemplary embodiments, short-length fibers can be adhered to the surface of the charge collector to facilitate the formation of a flocking structure to support the active material. Including short fiber sheets in the active material helps increase the porosity and / or reactivity of the electrode, which helps reduce the amount of active material required to form the electrode. If the fiber sheets are coated in carbon, the resulting plate can also be used as an EDLC.

[0068] In various exemplary embodiments, a veil layer (not shown) comprising a fibrous mesh is included in the electrode. The veil layer may be included between the active material and the charge collector, and / or located above the active material or at least partially embedded in the active material. In various embodiments, the veil layer is formed of capillary fibers of the type discussed above. The fibers comprising the veil layer may be preloaded with materials such as electrode active materials, carbon (e.g., graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, and / or CNTs), silicon, and / or acids. In various exemplary embodiments, the veil layer is formed of carbon and / or coated or infused with carbon to help improve capacitance and conductivity (e.g., in sponge lead and carbon capacitor electrodes). In other embodiments, the veil layer is coated or infused with carbon and lead oxides to form a dual electrochemical cell electrode and an EDLC. The veil layer may be formed of a patterned woven or non-woven mesh to adjust the veil's ability to adhere to and / or support the active material. In various exemplary embodiments, the gauze layer may be used as part of the collector grid, with fibers directly coupled or connected to or otherwise forming or contributing to the formation of the plate connector.

[0069] Figure 8 A cross-sectional view is shown of an exemplary fiber 241 at least partially disposed (e.g., coated) with carbon 245 (e.g., graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, or CNTs) and electrolyte 224 on at least some of its surface (e.g., internal surfaces). In various embodiments, the fiber 241 is also infused with electrolyte and is at least partially surrounded by electrode active material 223. In various embodiments, the average distance between the shaped fibers 241 is approximately half the thickness of the battery electrode. However, other spacing may be used.

[0070] According to various exemplary embodiments, the battery cell includes an electrode having capillary fibers (e.g., high specific surface area fibers) extending into and / or through the electrode. In various exemplary embodiments, the capillary fibers facilitate the siphoning of electrolyte into the electrode (e.g., into the interior of the electrode) to help improve porosity and increase the effective surface area of ​​the electrode. In various exemplary embodiments, the fibers also help maintain the structural integrity of the electrode (e.g., to prevent structural degradation due to battery cycling) by acting as adhesive or reinforcing fibers.

[0071] According to various exemplary embodiments, the battery cell 230 includes an array 225 of capillary fibers loaded with electrode active material (e.g., lead-based paste). Figure 9 A cross-section of an exemplary fiber is shown. In various embodiments, the fiber array 225 is substantially immersed in the electrolyte solution 224. The fiber array 225 can be of any form (e.g., loose fibers, woven or non-woven felt, bundles, etc.). In various embodiments, for example, as shown... Figure 10 As shown, the fiber array 225 can be used as a current collector for the electrode, with some loaded with anodic active material and others loaded with cathodic active material. In various exemplary embodiments, electrodes made using such fibers can help reduce the amount of lead required, shorten or eliminate the drying process, eliminate the need for adhesives, and / or increase conductivity.

[0072] According to the various exemplary embodiments, carbon (e.g., graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, and / or CNTs) can be added to the fibers in any of the illustrated embodiments to obtain the EDLC effect from the fibers. The carbon additives contribute to the formation of a carbon-electrolyte interface for EDLC. In the various exemplary embodiments, adding CNTs to the fibers also increases conductivity along the fibers. In the various exemplary embodiments, the fibers contain carbon and are part of the electrochemical cell electrode to form an asymmetric capacitor.

[0073] According to various exemplary embodiments, Figure 11A-11C The electrode construction is illustrated. In various embodiments, capillary fibers are disposed (e.g., loaded) with electrode active material. Carbon additives may also be loaded onto the fibers. The fibers may also at least partially cover the battery separator. In various exemplary embodiments, as shown... Figure 11A As shown, a charge collector 201 (e.g., a grid, plate, or wire mesh) is provided. The charge collector is at least partially provided with or coated with electrode fibers 222, such as... Figure 11B As further illustrated, fibers can be disposed on one or both sides of the charge collector and / or coupled to the terminals. In various embodiments, such as Figure 11C As shown, fiber 222 is at least partially provided with electrode active material 223 on its outer surface in contact with the charge collector (e.g., the outer electrode active material may have the opposite polarity to the electrode active material loaded inside the fiber). The charge collector shown is a positive collector in the form of a lead plate grid or wire mesh, but it can be any charge collector or substrate. In some embodiments, the charge collector is a felt made at least partially of conductive capillary fibers. Any suitable or appropriate separator material can potentially be used. In various exemplary embodiments, the active material disposed inside the fiber is different from that coated on the outside (e.g., cathode active material versus anode active material).

[0074] In various alternative embodiments, except or instead Figure 11B and 11C The long fibers shown can be replaced by short fiber sheets disposed on one or more solar panel grids. In various embodiments, the fibers can also be disposed or applied in a “floating structure” to help support the active material.

[0075] like Figure 12AAs shown, according to various exemplary embodiments, the battery cell includes capillary fibers 241 coated with an anode or cathode active material 223. Figure 12B As shown, fiber 241 is at least partially insulated from the protective shell or outer casing 206 of the battery separator. In various exemplary embodiments, as Figure 12C As shown, the fiber 241 is formed into a felt 222 (e.g., woven or non-woven) comprising substantially equal or similar amounts of anode and cathode. In other exemplary embodiments, the battery cell may be formed with separate anode-only felt and cathode-only felt.

[0076] According to some exemplary embodiments, the electrode active material paste is provided (e.g., mixed) with carbon, such as graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, CNTs, or graphite-coated CNTs, to facilitate the formation of a carbon matrix within the electrode. Carbon fibers may be provided, for example, to increase the structural strength of the electrode active material, the porosity of the electrode, and / or the electrode's ability to function as an EDLC. According to various exemplary embodiments, the electrode is manufactured by producing a masterbatch of carbon nanofibers or CNTs (single-walled or multi-walled) and water (e.g., ultrasonic diffusion) or lead powder (e.g., diffusion via an extruder) and providing (e.g., mixing or fusing) a masterbatch of electrode active materials having an electrode active material mixture paste for forming the electrode active material mixture paste. In various embodiments, the paste is applied or otherwise disposed on at least a portion of an electrode substrate and dried and / or allowed to dry to form an electrode plate. This can be achieved by various methods, such as including rolling the mixture onto the substrate. In various exemplary embodiments, carbon is diffused substantially uniformly throughout the electrode. The carbon fibers can have various sizes and are used in various concentrations (e.g., approximately 0.05 to 5% by weight of the electrode mixture). In each exemplary embodiment, the addition of carbon fibers increases the capacitance of the EDLC without reducing its electrochemical cell capacity. In each exemplary embodiment, carbon fibers also improve the structural integrity of the electrode.

[0077] In various embodiments, the fibers may be made of conductive or conductive polymers that have undergone electrochemical doping (e.g., P-doping or N-doping) to serve as electrolyte capacitors. In various embodiments, both types of electrodes (e.g., anode and cathode) may be constructed from the same material capable of P-doping or N-doping (e.g., Type III) to serve as electrolyte capacitors. In various embodiments, a veil formed of fibers at least partially formed from conductive polymers may be added to the electrodes to provide EDLC functionality.

[0078] In various exemplary embodiments, microfibers are used to form energy storage devices. For the purposes of this disclosure, "microfiber" is any fiber having a denier per filament (dpf) of about 1.5 or less. This type of fiber is sometimes also referred to as "microdenier". Microfibers can have any cross-sectional shape, including circular. Microfibers can be used in any of the above embodiments in addition to or instead of fibers with a shape. Microfibers are particularly effective for capillary fluids due to their large surface area relative to their volume. Microfibers can be made of polymers such as polyester, polypropylene, polyethylene, and / or polyethylene terephthalate.

[0079] The use of microfibers in fabrics is known. Exemplary microfibers are disclosed, for example, in U.S. Patents 6,627,025, 7,160,612, and 7,431,869 and in John F. Hagewood, Ultra Microfibers: Beyond Evolution, http: / / www.hillsinc.net / Ultrabeyond.shtml, the entire contents of which are incorporated herein by reference. These types of microfibers can be used in the disclosed energy storage devices, whether or not they are formed as fibers or felt.

[0080] In some exemplary embodiments, microfibers are formed by stretching and processing a bicomponent filament in the range of 2-4 dpf and then dividing the filament into microfibers having 0.1 or lower dpf. Figure 13 A bicomponent filament with approximately 3 dpf is shown. 64 microfibers from the first component are present within the matrix of the second component. In this embodiment, the bicomponent filament is approximately 80% microfibers and 20% matrix. Since the bicomponent filament has a dpf of 3, the elongation can be the same as that used for standard copolymer fibers. Separating the microfibers from the matrix component by decomposing the matrix component can be performed before or after the filaments and / or microfibers are formed into a felt or other energy storage device structure. Figure 14 A bicomponent filament with 1120 microfibers per filament, formed using the above-described technique of decomposing matrix components, is shown, wherein a portion of the bicomponent filament is separated into microfibers.

[0081] In each exemplary embodiment, microfibers are formed by stretching 2-4 dpf bicomponent yarn filaments, the stretching being performed using conventional techniques. In each exemplary embodiment, a neutral corrosive agent is applied to the yarn to separate the individual microfibers from the bicomponent yarn filaments. Figure 15 Microfibers with a density of approximately 0.1 dpf, manufactured according to this technology, are shown.

[0082] In some exemplary embodiments, yarn filaments are separated into microfibers without the use of a corrosive agent. This separation can be achieved, for example, by... Figure 16 The diagram shows divisible hollow fibers. In each exemplary embodiment, polyester / polypropylene filaments are drawn and then divided. Figure 15 A filament having 198 3-dpf filaments prior to processing is shown. In various exemplary embodiments, the filament is mechanically extracted to produce 3168 microfibers having approximately 0.2 dpf.

[0083] In each exemplary embodiment, and as Figure 17 As shown, the microfibers are formed from bicomponent filaments having a first polymer core and a smaller amount of a second polymer at the tip of the filament in a trefoil or delta cross-section. Figure 17 In the illustrated embodiment, the core polymer is a melt-stretchable polyurethane and the tip is polypropylene. The ratio of the two polymers is approximately 70% polyurethane to 30% polypropylene. As shown, the filament is manufactured using a standard fully oriented yarn stretching / drawing process and the filament has a dpf of approximately 3. After stretching, in each exemplary embodiment, the filament is twisted and subjected to a hydrothermal treatment to facilitate the production of, for example,... Figure 17 The filaments shown are spirally arranged around a core that separates from the core forming microfibers with a dpf of approximately 0.2 or less. The filament core can also shrink during heat treatment.

[0084] In various exemplary embodiments, microfibers are used in their "initial form," carbonized, and / or pre-coated with engineered materials (e.g., metals, carbon (e.g., graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, and / or CNTs), silicon, tin oxides, and / or acids). In various exemplary embodiments, the microfibers are pretreated using various methods and approaches. The pre-coated materials may include nanoscale materials, such as nanofibers and nanotubes. The coating can be applied via diffusion and deposition in the form of solvents (e.g., water, acid, or other solvents), by spraying, or by immersion in the microfibers (e.g., in a conductive metal). For example, many materials that can form microfibers have higher melting points than lead-based electrode active materials. Thus, lead-based active materials can be applied to microfibers by immersing them in molten active material and allowing the active material to harden, solidify, and / or in other forms related to the microfibers.

[0085] Microfibers can be made of various materials, including conductive and / or dielectric materials. In various embodiments, the microfibers are made of two or more materials (e.g., a conductive core and a dielectric surface). The microfibers may be conductive in or inside their core and non-conductive on or outside their surface, which would allow the core to function as a current collector for a capacitor formed of a dielectric material. This can be achieved at least in part by, for example, coating the conductive microfibers with a dielectric.

[0086] In various exemplary embodiments, the microfibers are coated with carbon (e.g., graphite, expanded graphite, activated carbon, carbon black, carbon nanofibers, and / or CNTs). The carbon material may be coated or otherwise disposed on microfibers in their original form (i.e., without any binder material) or in the form of a composite with a known amount of binder added to the carbon, to form a stable porous composite on the microfibers. CNTs, carbon nanofibers, and carbon whiskers can also be grown on various microfiber substrates.

[0087] In various embodiments, microfiber segments (e.g., short microfiber sheets) are disposed on one or more solar panel grids. In various embodiments, the microfibers thus manufactured are configured as a “floating structure” that can help support the active material.

[0088] In various exemplary embodiments, microfibers are used to form battery electrodes, wherein the microfibers are carbonized or graphitized and coated or otherwise disposed with active material. In various embodiments, the microfibers are made of polymers (e.g., polyolefins). In various exemplary embodiments, metal particles (e.g., nickel, iron, cobalt, molybdenum) are disposed (e.g., applied to their surface), which can be achieved by any suitable means, such as spraying. In various embodiments, the metal particles are a substrate or seed on which carbon fibers (e.g., CNTs) can be formed or grown. In various exemplary embodiments, the active material is disposed or applied around the carbon microfiber / nanotube bundle and / or through the carbon microfiber / nanotube bundle by pressing or rolling the active material. In various exemplary embodiments, the bundle is moistened using an electrolyte solution. At any point in the process, individual microfibers can be formed into bundles or felts, which can be woven or non-woven.

[0089] Individual microfibers can be straight or non-straight. In various exemplary embodiments, the microfibers can be coiled fibers, loop fibers, crimped fibers, air-jet interlocked fibers, or combinations of these and other shapes.

[0090] In various exemplary embodiments, the microfibers are disposed or otherwise formed as a felt (e.g., woven, non-woven, or dot-bonded). In various embodiments, an active material (e.g., lead oxide) is disposed (e.g., coated) on the microfiber felt to form an electrode for an electrochemical battery. The microfibers may also be coated with carbon or nanotubes (and in at least some embodiments, thus serving as EDLCs). Such embodiments can contribute to increased lifetime, generate a high interfacial area thereby increasing the bilayer capacitance for the active electrode, help optimize charge acceptance and / or high-speed discharge, and / or improve the conversion efficiency (e.g., initial charge) of the active material.

[0091] In various exemplary embodiments, sheets (e.g., short sheets) of microfibers are inserted, mixed, or otherwise disposed together with the active material. A mixture of short microfiber sheets and active material can be disposed (e.g., coated) on a conventional charge collector (e.g., a grid, plate, or mesh) or on a fiber felt. In various exemplary embodiments, short-length microfibers can be adhered to the surface of the charge collector to form a flocked structure to support the active material. Including short microfiber sheets in the active material helps increase the porosity and / or reactivity of the electrode, which helps reduce the amount of active material required to form the electrode. Electrodes can also be used in EDLCs if the microfiber sheets are coated in carbon.

[0092] In various exemplary embodiments, a veil layer comprising a microfiber mesh is included in the electrode. The veil layer may be included between the active material and the charge collector, and / or located above the active material or at least partially embedded in the active material. In various embodiments, the veil layer is formed from microfibers of the type discussed above. The microfibers comprising the veil layer may be pre-coated with materials such as the active material, carbon, silicon, graphite, and / or acids. In various exemplary embodiments, the veil layer is formed of carbon and / or coated or infused with carbon to help improve capacitance and conductivity (sponge lead and carbon capacitor electrodes). In other embodiments, the veil layer is coated or infused with carbon and lead oxides to form a dual electrochemical cell electrode and an EDLC. The veil layer may be formed from woven or non-woven meshes of various patterns to adjust the veil's ability to adhere to and / or support the active material. In various exemplary embodiments, the veil layer may serve as a collector grid having microfibers directly coupled to or connected to, or otherwise formed or facilitated in forming a plate connector.

[0093] According to various exemplary embodiments, the battery cell includes an electrode having microfibers extending into and / or through the electrode. In various exemplary embodiments, the microfibers facilitate the drawing of electrolyte into (e.g., into the interior of the electrode) the electrode (e.g., the active material) to help improve porosity and increase the effective surface area of ​​the electrode. In various exemplary embodiments, the microfibers also help maintain the structural integrity of the electrode (e.g., during battery charging and discharging) by acting as transporting or reinforcing fibers.

[0094] According to various exemplary embodiments, the battery cell includes an array of microfibers coated with an active material (e.g., paste). In various embodiments, the microfibers are substantially immersed in an electrolyte solution. The microfiber array can be of any form (e.g., loose fibers, woven or non-woven felt, bundles, etc.). In various embodiments, the microfibers serve as electrodes (e.g., conducting current), with some microfiber arrays coated in an anode active material and others coated in a cathode active material.

[0095] In various embodiments, the microfibers may be made of conductive or conductive polymers that have undergone electrochemical doping (e.g., P-doping or N-doping) to serve as electrolyte capacitors. In various embodiments, both electrode types may be made of the same material capable of P-doping or N-doping (e.g., Type III) to serve as electrolyte capacitors. In various embodiments, a veil formed of microfibers made of conductive polymers may be added to the electrode to provide EDLC functionality to the electrode.

[0096] As used herein, the terms “generally,” “approximately,” “substantially,” and similar terms are intended to have a broad meaning consistent with common and acceptable use by one of ordinary skill in the art to which the subject matter of this disclosure pertains. Those of ordinary skill in the art who peruse this disclosure will understand that these terms are intended to allow for the description of certain features described and claimed, rather than limiting the scope of these features to the precise numerical ranges provided. Therefore, these terms should be interpreted as indicating that non-substantial or unnecessary modifications or variations to the described and claimed subject matter are considered to fall within the scope of the invention as cited in the appended claims.

[0097] For the purposes of this disclosure, the term "coupled" means that two components are directly or indirectly joined to each other. This joining can be inherently static or movable. This joining can be achieved using two components, or two components and any additional intermediate component integrally formed with each other, or two components and any additional intermediate component attached to each other. This joining can be inherently permanent, or inherently removable or detachable. The term "coupled" includes creating a connection between two components that allow current to flow between them.

[0098] It is equally important to note that the construction and arrangement of the electrical energy storage devices, as illustrated in the various exemplary embodiments, are merely illustrative. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art will readily recognize that many modifications are possible (e.g., variations in size, scale, structure, shape and proportion of various elements, parameter values, mounting configuration, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described herein. For example, an element represented as integrally formed may be composed of multiple parts or elements, the position of elements may be reversed or otherwise altered, and the nature and number or position of discrete elements may be modified or changed. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. Other substitutions, modifications, alterations, and omissions may be made to the design, operating conditions, and construction of the various exemplary embodiments without departing from the scope of the invention.

Claims

1. An electrode comprising: a charge collector; an electrode active material coated on the charge collector; and carbonized fibers formed into a felt, wherein the felt is disposed on the charge collector; wherein the carbonized fibers are at least partially embedded in the electrode active material; wherein the felt comprises a plurality of shaped fibers, wherein at least a portion of the fibers are at least one of coiled fibers, looped fibers, and air-laid interlaced fibers, and have at least one of a trilobal cross-section, a substantially circular cross-section, and a quadrilobal cross-section; wherein the shaped fibers are formed from polypropylene, polyethylene, and / or polyethylene terephthalate; and wherein the shaped fibers have a cross-sectional diameter of 1 micron to 100 microns.

2. The electrode of claim 1, wherein the felt is formed from a pattern of woven or non-woven mesh to adjust the ability of the felt to adhere and / or support the active material.

3. The electrode of claim 1, wherein the felt is woven.

4. The electrode of claim 1, wherein the felt is a woven or non-woven mesh.

5. An electrode comprising: a charge collector; an electrode active material coated on the charge collector; and carbonized microfibers formed into a felt, wherein the felt is disposed on the charge collector; wherein the carbonized microfibers are at least partially embedded in the electrode active material; wherein the felt comprises carbonized microfibers, wherein the carbonized microfibers have a denier per filament of 1.5 or less; and wherein the carbonized microfibers are formed from polypropylene, polyethylene, and / or polyethylene terephthalate.

6. An electrode comprising: a charge collector; an electrode active material coated on the charge collector; and shaped fibers formed into a felt and coated with a carbon additive, the felt disposed on the charge collector, the carbon additive selected from the group consisting of graphite, activated carbon, carbon black, carbon nanofibers, and carbon nanotubes, the shaped fibers at least partially embedded in the electrode active material, wherein the felt comprises a plurality of the shaped fibers, wherein at least a portion of the fibers are at least one of coiled fibers, looped fibers, and air-laid interlaced fibers, and have at least one of a trilobal cross-section, a substantially circular cross-section, and a quadrilobal cross-section; wherein the shaped fibers are formed from polypropylene, polyethylene, polyethylene terephthalate, and / or glass; and wherein the shaped fibers have a cross-sectional diameter of 1 micron to 100 microns.

7. The electrode of claim 6, wherein the felt is a woven or non-woven mesh.

8. The electrode of claim 6, wherein the felt is formed from a pattern of woven or non-woven mesh to adjust the ability of the felt to adhere and / or support the active material.

9. The electrode of claim 6, wherein the graphite comprises expanded graphite.

10. An electrode comprising: a charge collector; an electrode active material coated on the charge collector; and ​ ​ ​ ​ microfibers, the microfibers being formed into a mat and coated with a carbon additive, the mat being disposed on the charge collector, the carbon additive being selected from the group consisting of graphite, activated carbon, carbon black, carbon nanofibers, and carbon nanotubes, the microfibers being at least partially embedded in the electrode active material, wherein the mat includes a plurality of the microfibers, wherein the microfibers have a denier per filament of 1.5 or less; wherein the microfibers are formed from polypropylene, polyethylene, and / or polyethylene terephthalate.

11. The electrode of claim 10, wherein the graphite comprises expanded graphite.

12. A battery having the electrode of claim 1 or claim 5.

13. A battery having the electrode of claim 6 or claim 10.

14. An electrode, comprising: a charge collector; an electrode active material coated on the charge collector; and the charge collector includes fibers, the fibers being formed into a mat and having a carbon additive, the carbon additive being selected from the group consisting of graphite, activated carbon, carbon black, carbon nanofibers, and carbon nanotubes, the fibers being at least partially embedded in the electrode active material, wherein at least a portion of the fibers are at least one of a cabled fiber, a looped fiber, and a spunlaced fiber, and have at least one of a trilobal cross-section, a substantially circular cross-section, and a quadrilobal cross-section; wherein the fibers are formed from polypropylene, polyethylene, polyethylene terephthalate, and / or glass; and wherein the fibers have a cross-sectional diameter of 1 micron to 100 microns.

15. An electrode, comprising: a charge collector; an electrode active material coated on the charge collector; and the charge collector includes microfibers, the microfibers being formed into a mat and having a carbon additive, the carbon additive being selected from the group consisting of graphite, activated carbon, carbon black, carbon nanofibers, and carbon nanotubes, the microfibers being at least partially embedded in the electrode active material, wherein the microfibers have a denier per filament of 1.5 or less; wherein the microfibers are formed from polypropylene, polyethylene, and / or polyethylene terephthalate.

16. A lead acid battery, comprising: a positive electrode and a negative electrode, the positive electrode and the negative electrode being housed within a casing having an electrolyte; and the negative electrode includes a mat of fibers, the fibers including a carbon additive, the carbon additive being selected from the group consisting of graphite, activated carbon, carbon black, carbon nanofibers, and carbon nanotubes, wherein the fibers are loaded with an electrode active material, and, further, wherein at least a portion of the fibers are selected from the group consisting of a trilobal cross-section fiber and a quadrilobal cross-section fiber, each cross-section fiber having a radial portion and an end portion, the end portion extending from the radial portion and being at least substantially orthogonal to the radial portion; wherein the fibers are formed from polypropylene, polyethylene, polyethylene terephthalate, and / or glass.

17. The battery of claim 16, wherein the graphite comprises expanded graphite.

18. The battery of claim 16, further comprising a separator between the positive electrode and the negative electrode. ​ ​ 19. The battery of claim 16, wherein the fibers have a cross-sectional diameter of 1 micron to 100 microns; and / or wherein the fibers are shaped fibers, the shaped fibers being at least one of coiled fibers, looped fibers, and air-laid interlaced fibers; and / or wherein the fibers are microfibers, wherein the microfibers have a denier per filament of 1.5 or less.

20. The battery of claim 16, wherein the mat is formed of a pattern of woven or nonwoven mesh to achieve at least one of adhesion and support of the electrode active material.

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