Patent Application
20150171462
The present invention relates to battery-related technique, and more particularly, to electrode assembly, battery including the same, and method of fabricating the same.
Active researches are being made in battery industry based on expansion of industry related to portable electronic devices due to recent developments in semiconductor fabricating technologies and communication technologies and demands for developing alternative energies based on environment preservation and depletion of natural resources. As the representative example of battery, a lithium primary battery features relatively high voltage and high energy density as compared to conventional aqueous solution based batteries, and thus a lithium primary battery may be easily miniaturized and light weighted. Such a lithium primary battery is used for various purposes, such as the main power supply for a portable electronic device and a backup power supply.
A secondary battery is a battery that is fabricated by using electrode materials with excellent reversibility and may be charged and discharged. The secondary battery may be categorized as cylindrical secondary battery and rectangular secondary battery based on the shape of it and may be categorized into nickel-hydrogen (Ni-MH) battery, lithium (Li) battery, lithium-ion (Li-ion) battery, etc., based on materials constituting a positive electrode and a negative electrode. Application of such a secondary battery is gradually expanding from small batteries for mobile phones, laptop PCs, and portable display devices to mid-size or large batteries, such as a battery for an electric motor vehicle and a battery used in a hybrid vehicle. Therefore, a secondary battery is demanded not only to be light weighted, exhibit high energy density, excellent charging/discharging speed, charging/discharging efficiencies, and cyclic characteristics, but also to exhibit high stability and economic feasibility.
Embodiments of the present invention includes an electrode assembly for battery, which exhibits high energy density, charging/discharging speed, charging/discharging efficiencies, and cyclic characteristics and may further easily be deformed, capacity-adjusted, and wound.
Embodiments of the present invention also include batteries, which include electrode assemblies having the above-stated advantages, may be easily connected to one another in series or in parallel, and exhibit excellent cooling efficiency.
Embodiments of the present invention also include methods of manufacturing batteries having the above-stated advantages.
According to an aspect of the present invention, there is provided an electrode assembly including an electric insulation layer comprising a base unit having a first main surface and a second main surface opposite to the first main surface; a first electrode formed on the first main surface of the electric insulation layer; a first lead electrically connected to the first electrode and extending out of the electric insulation layer; a second electrode formed on the second main surface of the electric insulation layer and having different polarity from that of the first electrode; a second lead electrically connected to the second electrode and extending in a direction opposite from the extending direction of the first lead; and a separator arranged on at least one of the first electrode and the second electrode.
The electric insulation layer may include a first anti-leakage unit formed along an edge of the first main surface of the base unit to have a relatively large thickness; and a second anti-leakage unit formed along an edge of the second main surface of the base unit to have a relatively large thickness. The first anti-leakage unit may be formed outside the first electrode and the first lead.
The first electrode may include a first current collecting layer formed on the first main surface; and a first active material layer formed on the first current collecting layer. The first lead may be directly connected to the first current collecting layer. The first lead may be integrated with the first current collecting layer. The second anti-leakage unit may be formed outside the second electrode and the second lead.
The second electrode may include a second current collecting layer formed on the second main surface; and a second active material layer formed on the second current collecting layer. The second lead may be directly connected to the second current collecting layer. The second lead may be integrated with the second current collecting layer.
The first lead and the second lead may extend out of the separator. The electric insulation layer may include a natural or synthetic flexible resin-based material.
The electrode assembly may be wound, such that the electric insulation layer forms the innermost layer, the intermediate layer, and the outermost layer. The plurality of first leads may be arranged and electrically connected to one another, whereas the plurality of second leads may be arranged and electrically connected to one another.
According to another aspect of the present invention, there is provided a battery including the above-stated electrode assembly; a roll core arranged at an end portion of the electric insulation layer in a direction parallel to the winding axis; and a case for accommodating the electrode assembly and the roll core.
The roll core may have a hollow cylindrical or rectangular shape. Insulating coating layers may be formed on surfaces of the roll core and the case, the surfaces not contacting the electrode assembly.
The battery may further include a first terminal unit arranged at first end portions of the roll core and the case and electrically connected to the first lead. The first terminal unit may include a first cover covering the roll core and the case; a protrusion extending outward from the first cover; and a first terminal attached to the first cover and the protrusion and electrically connected to the first lead.
The battery may further include a second terminal unit arranged at second end portions of the roll core and the case and electrically connected to the second lead. The second terminal unit may include a second cover covering the roll core and the case; a protrusion extending outward from the second cover; and a second terminal attached to the second cover and the protrusion and electrically connected to the second lead.
The battery may further include a first terminal unit arranged at first end portions of the roll core and the case and electrically connected to the first lead; and a second terminal unit arranged at second end portions of the roll core and the case and electrically connected to the second lead, wherein the first terminal unit and the second terminal unit may be inserted and coupled to each other and decoupled from each other.
A voltage sensing unit may be coupled to at least one of the first and second terminal units. A temperature sensing unit may be coupled to at least one of the first and second terminal units.
According to another aspect of the present invention, there is provided a method of fabricating a battery, the method including forming an electrode assembly including an electric insulation layer including a base unit having a first main surface and a second main surface opposite to the first main surface; a first electrode formed on the first main surface of the electric insulation layer; a first lead electrically connected to the first electrode and extending out of the electric insulation layer; a second electrode formed on the second main surface of the electric insulation layer and having different polarity from that of the first electrode; a second lead electrically connected to the second electrode and extending in a direction opposite from the extending direction of the first lead; and a separator arranged on at least one of the first electrode and the second electrode; winding the electrode assembly around a roll core as a winding axis to have a roll structure, such that the first electrode and the second electrode face each other across the separator and form an electrochemical reacting area; and coupling the electrode assembly wound around the roll core to a case.
According to an embodiment of the present invention, since an electrode assembly is provided as a single structure including electrodes having difference polarities and arranged respectively on a first main surface and a second main surface of an electric insulation layer, an electrochemical reacting area may be formed by simply winding the electrode assembly, such that the first electrode and the second electrode face each other via the separator.
Furthermore, according to an embodiment of present invention, since an electric insulation layer, which is thin and flexible unlike a metal, may act as a supporting unit, a metal current collecting layer, of which workability is deteriorated as thickness thereof increases, may be formed as a thin-film, thereby reducing the overall volume of an electrode assembly. As a result, energy density of a battery may be enhanced. Furthermore, since a roll core functions as a winding axis, workability may be improved during formation of an electrode assembly into a roll structure.
Furthermore, according to an embodiment of the present invention, a plurality of leads may be formed at least one of first and second electrodes embodied as rolls, thereby shortening current paths and reducing internal resistance of a battery. As a result, charging/discharging rate and efficiency and cycle characteristics of the battery may be improved.
Furthermore, in a battery according to an embodiment of the present invention, an air-cooling coolant or a liquid-cooling coolant may flow through a roll core having a hollow pipe-like shape, and thus a battery with improved cooling efficiency or heat dissipating efficiency may be provided. Furthermore, such a roll core functions as a center supporting unit or a center structure when a plurality of batteries are connected to one another and constitute a module or a pack, thereby improving mechanical strength of the batteries.
Furthermore, in a battery according to an embodiment of the present invention, a first terminal unit and a second terminal unit are formed to have shapes to be coupled to and/or decoupled from each other, and thus a plurality of batteries may be easily connected in series or in parallel.
Furthermore, in a battery according to an embodiment of the present invention, a voltage sensing unit and/or a cell voltage sensing connector unit is/are coupled to one of first and second terminal units, and thus the battery may be easily connected to a battery monitoring system.
Furthermore, according to an embodiment of the present invention, structure of an electrode assembly may be simplified, a thin and flexible electric insulation layer may become a supporting unit, reduce thickness of a metal current collecting layer, and help winding of a roll core. Therefore, a method of fabricating an electrode assembly that may be easily wound for packaging a battery and may be easily deformed and capacity-adjusted may be provided.
The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.
The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to one of ordinary skill in the art. Meanwhile, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments.
Also, thickness or sizes of layers in the drawings are exaggerated for convenience of explanation and clarity, and the same reference numerals denote the same elements in the drawings. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising” used herein specify the presence of stated features, integers, steps, operations, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof.
It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
Furthermore, the term ‘separator (isolation film)’ used throughout the present specification includes separator generally used in liquid electrolyte batteries using a liquid electrolyte with low compatibility with the separator. Furthermore, the term ‘separator’ used in the present specification includes an intrinsic solid polymer electrolyte and/or a gel solid polymer electrolyte, in which, the electrolyte and the separator may be considered as a same element component since the electrolyte is strongly bounded to the separator. Therefore, it is necessary to define the term ‘separator’ as defined in the present specification.
As shown in
The electric insulation layer 110 may include a base unit 113 including a first main surface 111 and a second main surface 112 opposite to the first main surface 111. As shown in
In an example of the present invention, to form the anti-leakage units 114 and 115 to be integrated with the base unit 113, the base unit 113 and the anti-leakage units 114 and 115 may be simultaneously formed by patterning or molding a material for forming the electric insulation layer 110, or the anti-leakage units 114 and 115 may be formed independently from the base unit 113 by laminating the anti-leakage units 114 and 115 on the base unit 113. The first anti-leakage unit 114 prevents outward leakage of a first active material layer constituting the first electrode 120, whereas the second anti-leakage unit 115 prevents outward leakage of a second active material layer constituting the second electrode 140.
In an example of the present invention, thicknesses of the first anti-leakage unit 114 and the second anti-leakage unit 115 may be greater than the base unit 113 that functions as a mechanical supporting unit and an electric insulator for separating the first electrode 120 and the second electrode 140 described below from each other. The first anti-leakage unit 114 and the second anti-leakage unit 115 may be formed on the other portion of the base unit 113 except the two opposite end portions AA and AB in the winding axis direction A. Detailed descriptions thereof will be given below.
The electric insulation layer 110 may include a flexible material that is suitable to form a roll structure and has sufficient mechanical strength. The flexible material may include natural or synthetic flexible resin-based materials. For example, the flexible resin-based material may be a cellulose-based resin, a polyester resin, such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), a polyethylene resin, a polypropylene resin, a polyvinyl chloride resin, a polycarbonate (PC), polyether sulfone (PES), polyether ether keton (PEEK), polyphenylene sulfide (PPS), polyimide, tri-acetyl cellulose, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, a polyamide-based resin, or a combination thereof, wherein the polyamide-based resin may be nylon 6, nylon 66, nylon 4, or nylon 6-11. However, the above-stated materials are merely examples, and the present invention is not limited thereto. Various other natural or synthetic flexible resin-based materials may also be applied thereto.
Thickness of the electric insulation layer 110 may be determined for the electric insulation layer 110 to have a sufficient strength to support the first electrode 120 and the second electrode 140, and at the same time, to be fabricated into a roll structure. For example, thickness of the electric insulation layer 110 may be from about 1 μm to about 100 μm and may preferably be from about 1 μm to about 10 μm. Since the electric insulation layer 110 has a thickness smaller than or equal to about 100 μm and may still provide excellent mechanical strength and deformability, the electric insulation layer 110 may contribute to reduction of the overall thickness of the electrode assembly 100. Advantages and features of the electric insulation layer 110 will become more clarified in the descriptions below.
The first electrode 120 is formed on the first main surface 111 of the electric insulation layer 110. The first electrode 120 may be an electrically positive electrode or an electrically negative electrode. The first electrode 120 may include a first current collecting layer 121 formed on the first main surface 111 and a first active material layer 122 formed on the first current collecting layer 121. If the first electrode 120 is an electrically positive electrode, the first current collecting layer 121 may contain a metal, such as aluminum, a stainless steel, titanium, or an alloy thereof, and may preferably include aluminum or an alloy thereof.
In other example of the present invention, the first current collecting layer 121 may be formed of a material other than the above-stated metals. For example, the first current collecting layer 121 may be formed of a conductive resin composition. The conductive resin composition may be a composite material including a resin for constituting a matrix and conductive particles dispersed in the matrix, such as metal particles or carbon particles. Alternatively, the conductive resin composition may be any of other resin-based materials known in the art, capable of conducting electrons.
Since the electric insulation layer 110 may support the first current collecting layer 121 and provide mechanical strength for forming a roll structure, the first current collecting layer 121 may be formed as a thin film. Thickness of the first current collecting layer 121 formed as a thin-film may be, for example, from about 0.01 μm to about 20 μm and may preferably be from about 0.01 μm to about 10 μm.
The first current collecting layer 121 including the above-stated metal may be formed by using a vapor deposition method for forming a thin conductive layer, such as pulsed laser deposition (PLD), RF sputtering, RF magnetron sputtering, DC sputtering, DC magnetron sputtering, metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or a combination thereof. However, it is merely an example, and the present invention is not limited thereto. For example, the first current collecting layer 121 may also be formed by using an electroless plating method for forming a thin-film by using an aqueous solution reaction between corresponding metal ions for constituting the first current collecting layer 121 and a reducing agent.
In an example of the present invention, the first current collecting layer 121 containing a metal may be metallic filaments (long fibers) having a thickness from about 1 μm to about 200 μm. The metallic filaments may be fibrously processed to have a suitable fibrous texture, such as a weaved structure, a felt-like structure, or a spiral structure in order to implement the first current collecting layer 121.
In other example of the present invention, if the first current collecting layer 121 contains the above-stated conductive resin composition, the first current collecting layer 121 may be formed by laminating a solid conductive film formed from mixture of a corresponding polymer resin with a conductor, such as metal powders and carbon particles, or by applying a liquid conductive composition and then drying the composition.
As described above, the first electrode 120 includes the first current collecting layer 121 and the first active material layer 122 stacked in the order stated. However, it is merely an example, and the present invention is not limited thereto. For example, a material capable of intercalation and deintercalation of metal ions and exhibiting excellent electric conductivity, such as carbon and carbon nanotubes, may function as both a current collecting layer and an active material layer at the same time. Therefore, when an electrode is formed by using such a material, the first current collecting layer 121 arranged below the first active material layer 122 may be omitted, thereby further reducing thickness of the first electrode 120.
After the first current collecting layer 121 is formed on the first main surface 111 of the electric insulation layer 110, the first active material layer 122 may be formed on the first current collecting layer 121. The first active material layer 122 may be formed on the first main surface 111 of the electric insulation layer 110 by using a method of paste, slurry, print, spray, or dry-coat as stated below. If necessary, a natural drying operation or a drying operation accompanied with a heating operation may be further performed. Furthermore, as described above, if the first current collecting layer 121 is formed to have a fibrous structure of metallic filaments, the first active material layer 122 may be impregnated into the first current collecting layer 121 or a mixture of the first current collecting layer 121 and the first active material layer 122 may be applied on to the electric insulation layer 110, such that the first current collecting layer 121 and the first active material layer 122 substantially form a common layer having a designated thickness.
The first active material layer 122 may include a suitable material based on whether a battery is a primary battery or a secondary battery and based on the corresponding polarity. For example, if the first electrode 120 is a positive electrode, the first active material layer 122 may include manganese oxide, electrolytic manganese dioxide (EMD), nickel oxide, lead oxide, lead dioxide, silver oxide, iron sulfide, or conductive polymer particles.
In a case of a secondary battery, the first active material layer 122 may include a Li compound containing at least one metal selected from a group consisting of Ni, Co, Mn, Al, Cr, Fe, Mg, Sr, V, La, and Ce and at least one non-metal ions selected from a group consisting of O, F, S, P, and combinations thereof. For example, a positive electrode active material layer may have a chemical formula LiaA1-bBbD2, where, in the chemical formula, A may be selected from a group consisting of Ni, Co, Mn, and combinations thereof, B may be selected from a group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare-earth atoms, and combinations thereof, and D may be selected from a group consisting of O, F, S, P, and combinations thereof, 0.95≦a≦1.1, and 0≦b≦0.5.
The first active material layer 122 may be particles having a size from about 0.01 μm to about 100 μm. Preferably, the first active material layer 122 may be particles having a size from about 0.1 μm to about 15 μm. However, it is merely an example, and a size of particles constituting the first active material layer 122 may be suitably selected based on characteristics required to a battery. In one example of the present invention, if the first active material does not contain a carbon-based material, such as graphite, the first active material layer 122 may further contain a conductive material. The conductive material may be added to the first active material layer 122 at a weight ratio of from about 2% to about 15% with respect to the overall weight of the first active material layer 122 mixed with the conductive material. The conductive material may be, for example, carbon black, ultrafine graphite particles, fine carbon like acetylene black, nano metal particle paste, or an indium tin oxide (ITO) paste.
The first lead 130 may be electrically connected to an exposed surface of the first current collecting layer 121, on which the first active material layer 122 is not formed, and may extend and protrude out of the electric insulation layer 110 by a designated length. The first lead 130 may be mechanically attached to, fused to, or welded to the first current collecting layer 121. The fusing or the welding may be performed by using a resistive method, a friction method, a laser method, or other adhering methods known in the art. However, the present invention is not limited thereto.
The first lead 130 may be a rectangular metal thin-film or may have a pattern other than a rectangular shape. Furthermore, the first lead 130 may include aluminum, titanium, a stainless steel, gold, tantalum, niobium, hafnium, zirconium, vanadium, indium, cobalt, tungsten, tin, beryllium, molybdenum, or an alloy thereof. Preferably, the first lead 130 may include aluminum or an aluminum alloy.
In one example of the present invention, the first lead 130 may be integrated with the first current collecting layer 121. For example, a portion of the first current collecting layer 121 may extend and protrude out of the electric insulation layer 110 by a designated length and may function as the first lead 130.
The second electrode 140 is formed on the second main surface 112 of the electric insulation layer 110. The second electrode 140 has a polarity opposite to that of the first electrode 120. The second electrode 140 may include a second current collecting layer 141 formed on the second main surface 112 and a second active material layer 142 formed on the second current collecting layer 141. If the second electrode 140 is an electrically negative electrode, the second current collecting layer 141 may be formed from copper, nickel, a stainless steel, or an alloy thereof and may preferably be formed of copper or a copper alloy.
In other example of the present invention, similar to the first current collecting layer 121 as described above, the second current collecting layer 141 may be formed from a non-metal material. For example, the second current collecting layer 141 may be formed from a conductive resin composition. The second current collecting layer 141 formed from a conductive resin component may be formed similarly as the first current collecting layer 121, and the descriptions related the first current collecting layer 121 given above may be referred to for the second current collecting layer 141.
Thickness of the second current collecting layer 141 may be selected in a same range as the range of thicknesses of the first current collecting layer 121. For example, thickness of the second current collecting layer 141 may be from about 0.01 μm to about 20 μm and may preferably be from about 0.01 μm to about 10 μm. As similar to the first current collecting layer 121, the second current collecting layer 141 including a metal may be a metal foil formed by using any of various deposition methods (e.g., pulsed laser deposition (PLD)), plating methods, and film forming methods (e.g., lamination) or a conductive layer having a weaved structure, a felt-like structure, or a combination thereof including metallic filaments. Furthermore, like the first current collecting layer 121, the second current collecting layer 141 may contain a conductive resin composition.
In other example of the present invention, the second electrode 140 may be formed of a material capable of intercalation and deintercalation of metal ions and exhibiting excellent electric conductivity, such as carbon and carbon nanotubes, and capable of functioning as both a current collecting layer and an active material layer at the same time. For example, the second current collecting layer 141 arranged above the second active material layer 142 may be omitted, thereby further reducing thickness of the second electrode 140.
After the second current collecting layer 141 is formed on the second main surface 112 of the electric insulation layer 110, the second active material layer 142 may be formed on the second current collecting layer 141. The second active material layer 142 may be formed on the second main surface 112 of the electric insulation layer 110 by paste coating a suitable material. If necessary, a natural drying operation or a drying operation accompanied with a heating operation may be further performed.
The second active material layer 142 may contain a suitable material based on whether the second active material layer 142 is for a primary battery or a secondary battery and polarity of thereof. For example, if the second electrode 140 is a negative electrode and a corresponding battery is a primary battery, the second active material layer 142 may include zinc, aluminum, iron, lead, or magnesium particles. Furthermore, if the corresponding battery is a secondary battery, the second active material layer 142 may include a carbon-based material capable of intercalating and deintercalating lithium ions, such as low-crystalline carbon or high-crystalline carbon. The low-crystalline carbon may be soft carbon or hard carbon. The high-crystalline carbon may a high temperature plastic carbon, such as natural graphite, Kish graphite, pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon micro-beads, mesophase pitches, and petroleum or coal tar pitch derived cokes. A negative electrode active material layer may include a binder material, where the binder material may be a polymer material, such as vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidenefluoride, polyacrylonitrile, and polymethylmethacrylate. In other example of the present invention, to provide a high-capacity secondary battery, the second active material layer 142 may contain a metal, such as S, Si, Sn, Sb, Zn, Ge, Al, Cu, Bi, Cd, Mg, As, Ga, Pb, and Fe, or an intermetallic compound, which may be alloyed or dealloyed with lithium. However, it is merely an example, and the present invention is not limited thereto. For example, a lithium foil or a lithium fiber with enhanced stability may be used.
Furthermore, like the first active material layer 122, the second active material layer 142 may be particles having a size from about 0.01 μm to about 100 μm. Preferably, the second active material layer 142 may be particles having a size from about 0.1 μm to about 15 μm. However, it is merely an example, and a size of particles constituting the second active material layer 142 may be suitably selected based on characteristics required to a battery. If the second active material layer 142 does not contain a carbon-based material, such as graphite, the second active material layer 142 may further contain a conductive material. The descriptions related the first active material layer 122 given above may be referred to for the details of weight ratios and types of such conductive materials.
The second lead 150 may be directly and electrically connected to a portion of the second current collecting layer 141, wherein the second active material layer 142 is not formed on the portion of the second current collecting layer 141, and may extend by a designated length out of the electric insulation layer 110 in an outward direction opposite to the first lead 130. The second lead 150 may be mechanically attached, fused, or welded to the second current collecting layer 141. The fusing or the welding may be performed by using a method selected from a resistive method, an ultrasonic method, a laser method, or any other equivalent method. However, the present invention is not limited thereto. In other example of the present invention, the second lead 150 may be integrated with the second current collecting layer 141. For example, the second current collecting layer 141 may extend out of the electric insulation layer 110 by a desired length and function as the second lead 150.
The second lead 150 may be a rectangular metal thin-film, a patterned metal thin film or metallic fibers. Furthermore, the second lead 150 may contain copper, nickel, tantalum, niobium, hafnium, zirconium, vanadium, indium, cobalt, tungsten, tin, beryllium, molybdenum, or an alloy thereof. Preferably, the second lead 150 may contain copper or a copper alloy.
The first and second leads 130 and 150 are entirely and electrically connected to edge portions of current collecting layers 121 and 141 in directions perpendicular to the winding axis direction AA described below, and thus, low-resistant bonding may be obtained based on such a sufficient contacting areas, and internal resistance of a battery may be significantly reduced. In addition, the bonding resistance may be constant regardless of a number of times that a roll structure is wound and thus a high-capacity and highly efficient battery may be implemented.
The separator 160 may be located at and closely contact a selected one of or both the first electrode 120 and the second electrode 140. The separator 160 may contain a fine porous membrane, a woven fabric, nonwoven fabric, an intrinsic solid polymer electrolyte film, a gel solid polymer electrolyte film, a fine porous membrane coated with inorganic ceramic powders, or a combination thereof. The intrinsic solid polymer electrolyte film may contain a linear polymer material or a cross-linked polymer material. The gel solid polymer electrolyte film may be one from a polymer containing a plasticizer including a salt, a polymer containing a filler, and a pure polymer or a combination thereof. The above-stated materials regarding the separator 160 are merely examples, and an arbitrary suitable electroinsulative material that may be easily deformed, exhibits excellent mechanical strength, and is not torn apart or broken due to deformation of the electrode assembly 100 may be used to form the separator 160, where the electroinsulative material may also exhibit a suitable ion conductivity. The separator 160 may be a single layer or multi layers, where the multi layers may be a stack of same single layers or a stack of single layers formed of different materials.
In consideration of durability, shutdown function, and safety of a battery, thickness of the separator 160 is from about 10 μm to about 300 μm, may be from about 10 μm to about 40 μm, and may preferably be from about 10 μm to about 25 μm. An end portion of the separator 160 may further extend in the axial direction of the winding axis A or out of an edge of the electric insulation layer 110 perpendicular thereto, such that length of the separator 160 becomes longer than that of the electric insulation layer 110. As described above, the extra portion of the separator 160 extending out of the electric insulation layer 110 provides a margin for deformation that may occur based on possible contraction-deformation of the electrode assembly 100 during chemical reaction of a battery, thereby preventing a short-circuit between the first and second electrodes 120 and 140. Furthermore, if a single battery is embodied with a plurality of electrode assemblies 100 to increase capacity of the battery, the extra portion of the separator 160 may be arranged between the plurality of electrode assemblies 100 and insulate the plurality of electrode assemblies 100 from one another.
According to the electrode assembly 100 of the above embodiments, compared to a conventional electrode assembly 100 in which electrodes having different polarities are separated and provided as two independent structures, the overall structure may be simplified, because a negative electrode and a positive electrode may be provided as a single structure, and a manufacturing process for aligning two separated electrodes in the conventional two independent electrode structure may be omitted in a process for fabricating battery 200, and thus the overall fabrication process may be simplified.
Furthermore, in case of an electrode assembly in the conventional in which a metal current collecting layer functions as a corresponding electrode, each of metal current collecting layers corresponding to a positive electrode and a negative electrode is generally designed to have a thickness equal to or greater than 20 μm. Considering that thicknesses of active material layers corresponding to a positive electrode and a negative electrode are from about 40 μm to about 100 μm, the overall thickness t1 of the electrode assembly becomes from about 60 μm to about 120 μm. As a result, in an electrode assembly in the related art, thickness ratio of first and second current collecting layers with respect to the overall thickness of the electrode assembly may be from ⅓ to ⅙.
However, according to the above embodiments of the present invention, the separate electric insulation layer 110 functions as a mechanical supporting structure instead of the first and second current collecting layers 121 and 141, thicknesses of the first and second current collecting layers 121 and 141 may be relatively small as compared to those in an electrode assembly in the conventional electrode assembly. For example, if it is assumed that thickness of each of the first and second active material layers 122, 142 is almost identical to thickness of an electrode assembly in the related art, that is, from about 20 μm to about 50 μm, thickness of each of the first and second current collecting layers 121 and 141 is about 0.01 μm, and thickness of the electric insulation layer 110 is about 1 μm, the overall thickness of the electrode assembly 100 may be from about 41 μm to about 101 μm. Therefore, a ratio (t2/t1) of a thickness t2 of each current collecting layer against the overall thickness t1 of the electrode assembly 100 may be from 1/41 to 1/101 and thus may be significantly reduced compared to the conventional electrode assembly. As a result, volume of the wound electrode assembly 100 can be also reduced due to reduced volume of the electrode assembly 100, and thus energy density may be increased with respect to a same volume, as compared to the conventional electrode assembly.
Furthermore, according to embodiments of the present invention, since the thin and flexible electric insulation layer 110 may support the electrode assembly 100, thicknesses of the first and second current collecting layers 121 and 141 may be reduced. Therefore, flexibility of the first and second current collecting layers 121 and 141 may be improved, and thus a winding operation for packaging the electrode assembly may be easily performed.
As shown in
As a result, the first active material layer 122 constituting the first electrode 120 is not leaked at least in the other direction of the winding axis direction A, e.g., a direction AB, other than the direction AA of the winding axis direction A. Furthermore, a portion of the electric insulation layer 110 corresponding to the first lead 130 is opened without the first anti-leakage unit 114, thereby preventing thickness of the electrode assembly 100 from excessively increasing nearby an area of the electrode assembly 100 where the first lead 130 protrudes.
Referring to
In other example of the present invention, although not shown, the second anti-leakage unit 115 may have a shape that surrounds the end AA that is parallel to the winding axis of the base unit 113 and the first anti-leakage unit 114 opens on, while opening the other end that is parallel to the winding axis of the base unit 113 and the first anti-leakage unit 114 closes on. In this case, the first anti-leakage unit 114 may have an L-like shape. In either case, the first lead 130 is formed at the end AA in the winding axis direction A, the second lead 150 is formed at the other end AB, the first anti-leakage unit 114 exists at the other end AB in the winding axis direction A, and the second anti-leakage unit 115 exists at the end AA in the winding axis direction A. Therefore, the first active material layer 122 constituting the first electrode 120 is not leaked via the other end AB in the winding axis direction A, and the second active material layer 142 constituting the second electrode 140 is not liked via the end AA in a winding axis direction A. As a result, despite of strong spinning pressure during fabrication of a roll structure, a short-circuit between the first electrode 120 and the second electrode 140 due to leakage of the active materials may be prevented. The first lead 130 and the second lead 150 as described above extend in directions opposite to each other toward the end AA and the other end AB in the winding axis direction A and protrude from side surfaces of the electric insulation layer 110, respectively. Therefore, if the first lead 130 is connected to a first electrode (120; e.g., a positive electrode) and the second lead 150 is connected to a second electrode (140; e.g., a negative electrode), a positive terminal and a negative terminal for battery may be formed in respective directions opposite to each other. In example of the present invention, the first lead 130 and the second lead 150 may further extend out of the separator 160 and may be electrically connected to terminals described below with ease.
In some examples of the present invention, the first electrode 120 and the second electrode 140 may be apart from end portions of the electric insulation layer 110 parallel to the winding axis direction by different distances. The innermost electrode arranged in a roll structure formed by winding the electric insulation layer 110 around the winding axis direction A may be the farthest distance apart from the winding axis direction A. For example, if a roll structure is formed by winding the electrode assembly 100 in the winding axis direction, such that the second main surface 112 on which the second electrode 140 is formed becomes the inner surface, the second electrode 140 may be farther apart from the winding axis direction A compared to the first electrode 120. As a result, an accurate facing area of the opposite electrodes may be obtained in a roll structure without wasting active materials constituting electrodes.
Referring to
As shown in
In any case of the directions in which the electrode assembly 100 is to be wound, as shown in
According to an embodiment of the present invention, since a winding operation may be easily performed due to the electric insulation layer 110 having excellent flexibility and the first and second current collecting layers 121 and 141 having reduced thicknesses, shape of the roll structure may be diversified. For example, the roll structure may be wound to have a circular cross-section, as shown in
As shown in
In some examples of the present invention, to increase capacity of a battery, the electrode assembly 101 may further include first and second sub electrode assemblies 100_1 and 100_2 facing the respective main surfaces of the electrode assembly 100 having the same configuration as the electrode assembly shown in
The first and second sub electrode assemblies 100_1 and 100_2 face each other via separators 160_1 and 160 on main surfaces of the electrode assembly 100, where polarity of electrodes of the first and second sub electrode assemblies 100_1 and 100_2 differs from that of the electrode on the corresponding main surface of the electrode assembly 100. For example, if an electrode of a main surface of the electrode assembly 100 faced by the first sub electrode assembly 100_1 is a positive electrode, an electrode 120_1 of the first sub electrode assembly 100_1 may be a negative electrode. Similarly, if an electrode of the other main surface of the electrode assembly 100 faced by the second sub electrode assembly 100_2 is a negative electrode, an electrode 140_1 of the second sub electrode assembly 100_2 may be a positive electrode. To this end, the electrodes 120_1 and 140_1 of the first and second sub electrode assemblies 100_1 and 100_2 may have suitable first current collecting layers 121_1 and 141_1 and active materials 122_1 and 142_1, respectively. The descriptions given above may be referred to for descriptions of these materials.
Electric insulation layers 110_1 and 110_2 of the sub electrode assemblies 100_1 and 100_2 may include base units 113_1 and 113_2, respectively, where anti-leakage units 114_1 and 115_1 may be respectively formed on corresponding main surfaces of the base units 113_1 and 113_2. As described above with reference to
The anti-leakage units 114_1 and 115_1 may be formed to open at least portions of edges perpendicular to the winding axis direction A and surround the remaining edges. Corresponding electrode layers and leads may be accommodated inside the anti-leakage units 114_1 and 115_1 formed as described above, and thus the leads may be exposed out of the electric insulation layers 110_1 and 110_2. In an example of the present invention, the anti-leakage units 114_1 and 115_1 may be formed at edge portions of the base units 113_1 and 113_2 to have a U-like shape or an L-like shape, as described above with reference to
The opened portions of the anti-leakage units 114_1 and 115_1 may be alternated inside a roll structure in a direction perpendicular to the winding axis direction A, that is, a diameter-wise direction from the spinning center of the roll structure. As a result, both end portions (or both end portions in the winding axis direction) of the roll structure may include a plurality of lead layers that are formed as leads connected to respective electrodes having a same polarity are successively exposed. A first polarity common lead unit 130A and a second polarity common lead unit 150A may be provided by physically contacting and electrically connecting the lead layers to one another at the respective end portions of a roll structure. The first polarity common lead unit 130A and the second polarity common lead unit 150A may extend outward further than end portions of the roll core 210 and the case 220
The opened portions of the anti-leakage units 114_1 and 115_1 may be alternated inside a roll structure in a direction perpendicular to the winding axis direction A, that is, a radial direction from the spinning center of the roll structure. As a result, a respective lead connected to respective electrodes having a same polarity may be exposed at both end portions (or both end portions in the winding axis direction) of the roll structure in a form of a multi layered structure. The lead in a multi layered structure may be electrically connected to one another, thereby providing the first polarity common lead unit 130A and the second polarity common lead unit 150A. The first polarity common lead unit 130A and the second polarity common lead unit 150A may extend outward further than end portions of the roll core 210 and the case 220.
The first polarity common lead unit 130A and the second polarity common lead unit 150A may be provided by temporarily welding the respective leads (refer to 130 and 150 of FIGS. 2A and 2B)exposed in the upward direction UP and the downward direction DW to each other. The first polarity common lead unit 130A and the second polarity common lead unit 150A may ease packaging of a battery and reduce internal resistance. The temporary welding may be provided via a resistive method, an ultrasonic method, a laser method, any other equivalent fusing, pressing, or clamping method, or an adhesive. However, the present invention is not limited thereto.
In the electrode assembly 101, only the second electrode 140 (or the first electrode 120) is disposed on a surface of the electric insulation layer 110 at a winding starting region (e.g., a region at which the roll core 210 is initially rolled once) and only the first electrode 120 (or the second electrode 140) is disposed on a surface of the electric insulation layer 110 at a winding ending region (e.g., a region at which the roll core 210 is rolled once for the last time), and thus an electrochemical reacting area may be embodied. From other point of view, if the second electrode 140 is arranged at the winding starting region, the first electrode 120 is arranged via the separator 160 on an outer side nearby the second electrode 140. Furthermore, if the first electrode 120 is arranged at the winding ending region, the second electrode 140 is arranged via the separator 160 on an inner side nearby the first electrode 120. Therefore, an electrochemical reacting area may be formed throughout the entire area of the electrode assembly 101 without a wasted electrochemical area.
Lengths (or heights) of the roll core 210 and the case 220 may be identical to or longer than length (or height) of the electrode assembly 101, and thus a first terminal unit and a second terminal unit as described below may be easily attached thereto.
Referring to
The first terminal unit 230 includes a first cover 230A, a protrusion 234, and a first terminal 235. The first terminal 235 may be electrically connected to a first common lead unit (refer to 130A of
The first cover 230A includes an inner cylinder unit 231 connected to the roll core 210 or extending from the roll core 210, an outer cylinder unit 232 connected to the case 220 or extending from the case 220, and a connecting unit 233 interconnecting the inner cylinder unit 231 and the outer cylinder unit 232. The protrusion 234 is formed at the connecting unit 233 and protrudes outward by a desired length, where the protrusion 234 may be formed to have a circular type.
The first terminal 235 is formed to have an approximately U-like shape including one inner wall 235a and two sidewalls 235b, where a first common lead unit (refer to 130A of
In some example of the present invention, the two sidewalls 235b of the first terminal 235 may be formed as bent wires with a linear pattern, a diagonal line pattern, a spiral pattern, or a curve line pattern for highly efficient flow of charging/discharging currents, and thus the sidewalls 235b may function as springs. Furthermore, embossings, protrusions, or other equivalent structures may be formed at the sidewalls 235b. In an example of the present invention, in the first terminal 235, an insulation-finished portion 236 may be formed on the protrusion 234 to maintain insulation in a normal state. However, the present invention is not limited thereto.
In an example of the present invention, the first terminal 235 may contain aluminum, titanium, stainless steel, gold, tantalum, niobium, hafnium, zirconium, vanadium, indium, cobalt, tungsten, tin, beryllium, molybdenum, or an alloy thereof. Preferably, the first terminal 235 may contain aluminum or an aluminum alloy.
The voltage sensing unit 237a and/or the temperature sensing unit 238a may be coupled to the first terminal unit 230. For example, as shown in
As shown in
Accordingly, a voltage detected by the voltage sensing unit 237a and a temperature detected by the temperature sensing unit 238a may be transmitted to a battery managing system or a battery monitoring system (BMS), and thus overcharging, over-discharging, and temperature state of a battery may be efficiently managed. In some examples of the present invention, the voltage sensing connector unit 237b and temperature sensing connector unit 238b or ambient areas may be formed to have different shapes to prevent incorrect insertion of the connectors.
Referring to
The second cover 244 includes an inner cylinder unit 241 connected to the roll core 210 or extending from the roll core 210, an outer cylinder unit 242 connected to the case 220 or extending from the case 220, and a connecting unit (not shown) interconnecting the inner cylinder unit 241 and the outer cylinder unit 242.
The second terminal 245 is formed to have an approximately n-like shape including one inner wall 245a and two sidewalls 245b, where a second common lead unit 150B may be electrically connected to the inner wall 245a. Furthermore, the two sidewalls 245b may closely contact inner walls of the inner cylinder unit 241 and the outer cylinder unit 242 constituting the second cover 244. Therefore, the second terminal 245 may have an overall concave groove-like shape.
In other example of the present invention, the two sidewalls 245b of the second terminal 245 may be formed as bent wires with a linear pattern, a diagonal line pattern, a spiral pattern, or a curve line pattern for highly efficient flow of charging/discharging currents, and thus the sidewalls 245b may function as springs. Furthermore, embossings, protrusions, or other equivalent structures may be formed at the sidewalls 245b.
If the second terminal 245 is an external terminal for a negative electrode, the second terminal 245 may contain copper, nickel, titanium, a stainless steel, gold, tantalum, niobium, hafnium, zirconium, vanadium, indium, cobalt, tungsten, tin, beryllium, molybdenum, or an alloy thereof. Preferably, the second terminal 245 may contain copper or a copper alloy.
Referring to
In an example of the present invention, the first terminal unit 230 and the second terminal unit 240 are formed to have the shape of respective terminal unit as shown in
The protrusion 234 of the first terminal unit 230 is coupled to a concave groove formed at the second terminal unit 240. As a result, as the first terminal 235 and the second terminal 245 contact each other, the first terminal 235 and the second terminal 245 may be electrically connected to each other without a separate bus structure. If necessary, the first terminal 235 and the second terminal 245 are formed to function as springs, mechanical strengths thereof and ease of coupling therebetween may be improved.
In an example of the present invention, the roll core 210 and/or the inner cylinder units 231 and 241 of the first and second terminals 235 and 245 are connected to one another and may have pipe-like shapes. As a result, a flow channel 210H in which an air-cooling coolant or a liquid-cooling coolant may flow for cooling a battery may be provided. Therefore, heat accumulated at the centers of batteries 200 and 300 may be efficiently dissipated, thermal equilibrium of the batteries 200 and 300 may be maintained, and thus heat-resistance of the batteries 200 and 300 may be improved. Furthermore, even if a plurality of batteries are connected in series, as shown in
Furthermore, when the plurality of batteries 200 are connected in series or in parallel and constitute a module or a pack, such a structure may function as a center supporting unit or a center supporting structure even though there is no center pin, and may enhance mechanical strength of the module or the pack.
An region of the roll core 210 and an region of the case 220 that are exposed out of the batteries 200 and 300 may be insulated. If the roll core 210 and the case 220 are formed as conductors, insulating coating layers may be formed at the region of the roll core 210 and the region of the case 220 exposed to outside. However, if the roll core 210 and the case 220 are formed as insulators, such insulating coating layers may be omitted. Accordingly, the batteries 200 and 300 according to the present invention may exhibit reliable electric insulation from an external device or an external system and may prevent an electric short-circuit, and thus it becomes easy to design circuits for an external device or an external system.
In an example of the present invention, an electrolyte may be injected into a space surrounded by the roll core 210, the case 220, the first terminal unit 230, and the second terminal unit 240, e.g., a space of a roll structure in which the electrode assembly 100 is arranged. For example, an aqueous electrolyte including a salt, such as potassium hydroxide (KOH), potassium bromide (KBr), potassium chloride (KCl), zinc chloride (ZnCl2), and sulfuric acid (H2SO4), may be absorbed into a roll structure, thereby activating the batteries 200 and 300. Furthermore, a non-aqueous electrolyte formed by mixing a mixed solvent containing a highly-dielectric carbonate solvent, such as propylene carbonate or ethylene carbonate, and a low viscosity carbonate solvent, such as diethyl carbonate, methyl ethyl carbonate, or a dimethyl carbonate, with a lithium electrolyte, such as LiBF4 and LiPF6, may also be absorbed into a roll structure, thereby activating the batteries 200 and 300. Although not shown, a suitable battery managing system for controlling stability during operation of the batteries 200 and 300 and/or power supply characteristics may be further coupled to the batteries.
Fabrication of the batteries 200 and 300 may be performed by formation of the electrode assembly 100, winding of the electrode assembly 100, coupling of the electrode assembly 100, coupling of the first terminal unit 230, injection of an electrolyte, and coupling of the second terminal unit 240. In the formation of the electrode assembly 100, the electrode assembly 100 including the electric insulation layer 110, which includes the first main surface 111 and the second main surface 112 opposite to the first main surface 111; the first electrode 120 formed on the first main surface 111 of the electric insulation layer 110; the first lead 130 electrically connected to the first electrode 120 and extending out of the electric insulation layer 110; the second electrode 140 formed on the second main surface 112 of the electric insulation layer 110; the second lead 150 electrically connected to the second electrode 140 and extending out of the electric insulation layer 110 in a direction opposite to the extending direction of the first lead 130; and the separator 160 closely contacting at least one of the first electrode 120 and the second electrode 140 may be provided. During the winding of the electrode assembly 100, the electrode assembly 100 may be wound around the roll core 210 as a winding axis, such that the first electrode 120 and the second electrode 140 face each other via the separator 160 and form an electrochemical reacting area.
In the coupling of the electrode assembly 100, the electrode assembly 100 wound around the roll core 210 is coupled to the case 220. In the coupling of the first terminal unit 230, the first terminal unit 230 (or the second terminal unit) may be assembled to first end portions of the roll core 210 and the case 220 and, at the same time, the electrode assembly 100 may be electrically connected to the first terminal unit 230. In the injection of the electrolyte, the electrolyte may be injected into a space defined by the roll core 210, the case 220, and the first terminal unit 230, that is, the internal space in which the electrode assembly 100 is arranged.
In the coupling of the second terminal unit 240, the second terminal unit 240 (or the first terminal unit) is assembled to the other end portions of the roll core 210 and the case 220 and, at the same time, the electrode assembly 100 is electrically connected to the second terminal unit 240. The injection of the electrolyte may be performed by injecting the electrolyte via an injection hole separately arranged at the case 220, the first terminal unit 230, or the second terminal unit 240, after the coupling of the first and second terminal units 230 and 240. In an example of the present invention, if the separator 160 includes an electrolyte, the injection of the electrolyte may be omitted.
Since a battery according to an embodiment of the present invention exhibits improved energy density and workability, the battery according to an embodiment of the present invention may be applied as a small battery for a small electronic device, such as a computer, a display apparatus, and a mobile phone, or may be applied as a mid-sized or large-sized battery as a power supply for an automobile or power storage by enhancing capacity of the battery through increase of volume of the battery. The above embodiments may replace or be combined with one another unless being contradictory to one another. For example, the roll structure of
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2012-0074229 | Jul 2012 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2013/005878 | 7/3/2013 | WO | 00 |
