Abstract: An energy storage cell having a flexible envelope, which cell is attached flat to a heat-conducting plate.

Abstract: An electrode terminal 42 is connected to a current collector part 12 of electrodes through a deformation restricting member 3. Between laminate films 2 and 2, a space 15 is formed above and below the current collector part 12. The deformation restricting member 3 is placed close to the inner wall peripheral portion of an outer package including sealing parts 23, thereby forming a deformation-restricting part 22 to restrict the inward deformation of the laminated films 2. In a section extending from the inside end of the deformation restricting member 3 to a battery element 1, the laminated films 2 face the space 15 to allow the deformation of the laminated films 2 in response to the change of internal pressure. At the decrease of internal pressure, the contraction of the laminated films 2 can be localized in the deformation-allowing part 21, thereby reducing the bending stress on an end portion of the sealing parts 23.

Abstract: The present invention provides a stack-type lithium-ion polymer battery wherein: the battery capacity is not being degraded; the generation of the wrinkles and fracture of the separator is being suppressed; the battery has gas releasing paths; the displacement of an electrode stack hardly occurs; and the workability at the time of placing the electrode stack in a package body is improved by fixing the electrode stack. A stack-type lithium-ion polymer battery of the present invention comprises: a cathode 13; an anode 14; a separator 15; and a gel electrolyte; wherein an electrode stack 23 in which the cathode 13 and the anode 14 are stacked through the separator 15 is enclosed and fixed by insulating porous sheets 21 and 24, and is packaged with a laminate material.

Abstract: Disclosed is a cathode material comprising a mixture of an oxide powder (a) defined herein and an oxide powder (b) selected from the group consisting of an oxide powder (b1) defined herein and an oxide powder (b2) defined herein and a combination thereof wherein a mix ratio of the two oxide powders (oxide powder (a): oxide powder (b)) is 50:50 to 90:10. The cathode material uses a combination of an oxide powder (a) and 50% or less of an oxide powder (b) which can exert high capacity, high cycle stability, superior storage stability and high-temperature stability, thus advantageously exhibiting high energy density and realizing high capacity batteries.

Abstract: Disclosed is a secondary battery including a cathode, an anode, a membrane and an electrolyte, wherein the cathode contains a mixture of a first cathode material defined herein and a second cathode material selected from the group consisting of a second-(a) cathode material defined herein and a second-(b) cathode material defined herein, and a combination thereof, wherein a mix ratio of the two cathode materials (first cathode material: second cathode material) is 50:50 to 90:10, and the membrane is an organic/inorganic composite porous membrane including (a) a polyolefin-based membrane substrate and (b) an active layer in which one or more areas selected from the group consisting of the surface of the substrate and a portion of pores of the substrate are coated with a mixture of inorganic particles and a binder polymer, wherein the active layer has a structure in which the inorganic particles are interconnected and fixed through a binder polymer and porous structures are formed by the interstitial volume bet

Abstract: The present invention relates to metal foil encapsulation of an electrochemical device. The metal foil encapsulation may also provide contact tabs for the electrochemical device. The present invention may also include a selectively conductive bonding layer between a contact and a cell structure.

Abstract: A stack type battery has a positive electrode plate (1) having a positive electrode active material layer (1a) formed on at least one side of a current collector made of a metal plate and a positive electrode current collector lead (11) provided in a portion thereof, the positive electrode plate (1) and the positive electrode current collector lead (11) facing a negative electrode plate across a separator (3a). A protective layer (13) made of a material having a lower electron conductivity than the metal of the current collector and being non-insulative is formed at a portion of the positive electrode plate (1) between the positive electrode current collector lead (11) and the separator (3a). The positive, electrode current collector lead (11) and the separator (3a) are joined to each other by the protective layer (13).

Abstract: A battery assembly includes a first cell and a second cell adjacent the first cell. A first insulator and a second insulator extend over and encapsulate first electrode and second electrode. A shell extends over the first and second insulators thereby encapsulating the first and second insulators. A mechanical connection is defined between the first insulator of the fist cell and the second insulator of the second cell.

Abstract: Disclosed is the present invention directed to a process for manufacturing an electrode assembly, including: prior to assembling to electrode, bending a cathode, having an active material layer coated on one major surface of a current collector, and an anode, having an active material layer coated on one major surface of another current collector, in a zigzag fashion in vertical sections; and after the bending of the cathode and the anode, fitting the cathode and the anode to each other, such that the electrode active material layers face each other, while a separator is disposed between the cathode and the anode.

Abstract: An electric storage device 10 has a positive electrode 13, a negative electrode 14 and a separator 15 provided between the positive electrode 13 and the negative electrode 14. The negative electrode surface 14b is formed to be larger than the positive electrode surface 13b in such a manner that a positive electrode outer edge 13c and a negative electrode outer edge 14c are apart from each other by 2 mm or more. By this configuration, an ion restricting section 15b is formed at the outer peripheral portion of the separator 15. Accordingly, the movement of the lithium ions toward the negative electrode end surface 14a can be restricted, when the device is charged with a large current, whereby the deposition of metal lithium on the negative electrode end surface 14a can be prevented.

Abstract: An electrode assembly includes a first electrode member; a second electrode member; a plurality of first guide portions, wherein at least one of the first guide portions is on the first electrode member; a plurality of second guide portions, wherein at least one of the second guide portions is on the second electrode member; and a separator located between the first electrode member and the second electrode member, wherein the electrode assembly has a first region at which the first guide portions are coupled together and a second region at which the second guide portions are coupled together.

Abstract: A secondary battery which can maintain alignment between a first electrode plate and a second electrode plate and can improve the cell stability and life characteristic of the battery, and a manufacturing method thereof. A secondary battery includes an electrode assembly including a first electrode plate; a second electrode plate; a first separator between the first electrode plate and the second electrode plate and including a central portion and an outer portion at a periphery of the central portion; and a second separator at a side of the first electrode plate or the second electrode plate opposite a side facing the first separator, the second separator including a central portion and an outer portion at a periphery of the central portion of the second separator, and the outer portion of the first separator and the outer portion of the second separator contact each other at least at a joining part.

Abstract: Provide an electrochemical device offering a large capacity per current collector and a low internal resistance, which is also easy to assemble. Provided is a laminated sheet body 16S by inserting a negative-electrode continuous body 11BW between an adjacent pair of first current collectors 12a, 12a with their first current collector main units 12a1 connected together, and also between an adjacent pair of first current collectors 12a, 12a with their first tabs 12a2 connected together, with respect to a plurality of positive electrodes 11A arranged in the width direction apart from each other, after which the negative-electrode continuous body of the laminated sheet body is cut to the unit width dimension of an element to obtain a plurality of laminated bodies 16.

Abstract: A method of synthetic imaging comprising the steps of: emitting a first electromagnetic signal having a first frequency from a first radiation source, emitting at least one second electromagnetic signal having a second frequency from a second radiation source, wherein the first and second frequencies are different from each other, substantially simultaneously receiving the first signal and the second signal with a first receiver, substantially simultaneously receiving the first signal and the second signal with at least one second receiver, arranging an object on the path of at least one electromagnetic signal between the radiation sources and the receivers, wherein the signals are reflected by the object before they meet the receivers, and computing an image of the object from the signals received by the receivers and a device for practicing the method.

Abstract: An electrode assembly that includes a positive electrode assembly including a number of positive electrodes each having a positive electrode non-coating portion at a certain position, and a positive electrode tab coupling all the positive electrode non-coating portions, a negative electrode assembly including a plurality of negative electrodes each having a negative electrode non-coating portion at a certain position, and a negative electrode tab coupling all the negative electrode non-coating portions, and a separator disposed between each positive electrode and each negative electrode to insulate a region between the positive electrode and the negative electrode. The positive electrodes of the positive electrode assembly and the negative electrodes of the negative electrode assembly are stacked alternately.

Abstract: An electrode assembly and a secondary battery using the same. In an embodiment, the electrode assembly includes one or more first electrodes each having a first tab provided to one surface thereof, and one or more second electrodes each having a second tab provided to one surface thereof. The second electrodes are alternately stacked with the first electrodes. A separator is interposed between the first and second electrodes and folded a plurality of times so that the same surfaces of the separator face each other. The separator has one or more tab through-holes through which the first and second tabs protrude at folded portions of the separator.

Abstract: The present invention relates to a pouch type case having trimming portions formed on both sides or four corners thereof and a battery pack including the same. The trimming portions are formed on the corners of the pouch type case such that the trimming portions are indented toward an electrode assembly accommodating part to reduce a unit area so as to increase pressure applied to unit cells when a battery pack is assembled, thereby facilitating assembling of the battery pack and increasing cell capacity per unit area. Furthermore, the unit cells can be fixed in the battery pack more stably. The pouch type case reduces the unit area so as to include a relatively large number of cells for pressure applied to the cells when the battery pack is assembled to thereby increase the cell capacity.

Abstract: The present invention provides a lithium-ion secondary battery which can suppress internal resistance to a small value. The lithium-ion secondary battery includes a winding group obtained by winding a positive electrode plate and a negative electrode plate via a separator. An end portion of a positive electrode mixture non-application portion 1 projects at an upper portion of the winding group, while an end portion of a negative electrode mixture non-application portion projects at a lower portion of the winding group. Current collecting disks 7 are disposed on both end faces of the winding group so as to face them, respectively, and materials for the current collecting disks are the same materials as those for a positive electrode current collector and a negative electrode current collector.

Abstract: Disclosed are a plate assembly for a battery, a core and a lithium ion battery. The plate assembly comprises a plate, a conductive terminal and a membrane bag, the plate is encapsulated in the membrane bag, an encapsulation line is formed when the membrane bag is encapsulated, and the conductive terminal is disposed at one end of the plate and protruded out of the membrane bag, wherein the encapsulation line has at least two loops around the periphery of the plate. The core comprises the plate assembly of the present invention. The lithium ion battery comprises the core of the present invention.

Abstract: A secondary battery includes an electrode assembly, an insulation bag, a case, and a cap plate. The electrode assembly includes first and second electrodes, and a separator between the electrodes. The insulation bag has an open top and houses the electrode assembly. The case houses the electrode assembly and the insulation bag. The cap plate seals the case. The insulation bag includes first and second side surface portions, and first and second extending portions. The first and second side surface portions face one another and extend from one side to an opposite side. The first extending portion extends from an upper end of the first side surface portion at the one side. The second extending portion extends from an upper end of the second side surface portion at the opposite side.

Abstract: An electrode system includes one or more separator materials formed into a bag having at least two seams. The seams are positioned so as to define the perimeter of a pocket configured to receive an electrode within the bag. At least one gap is formed between seams adjacent to one another along the perimeter of the pocket. Additionally, at least one of the seams includes a spacer positioned between portions of the one or more separator materials joined by the at least one seam.

Abstract: A pouch type secondary battery having enhanced reliability by protecting the battery from external impacts is described. A reinforcement structure may be installed on a pouch casing and an electrode assembly housed in the pouch casing. Short-circuits inside the pouch casing may be minimized. The pouch type secondary battery has an electrode assembly with positive and negative electrode plates with a separator interposed therebetween, and positive and negative terminal portions extending from the positive and negative electrode plates. A first reinforcement member is closely adhered to one or more planes of the electrode assembly. A second reinforcement member may be adhered to the pouch casing and used with or without the first reinforcement member.

Abstract: A stack type battery has a plurality of positive electrode plates (1) and a plurality of negative electrode plates (2), which are alternately stacked one on the other with separators (3) interposed therebetween. It also has positive electrode leads (11) and negative electrode leads (12) protruding from the respective electrode plates (1, 2) and being stacked and joined to a positive electrode current collector terminal (15) and a negative electrode current collector terminal (16), respectively. Peripheral portions of the separators that face each other across each of the positive electrode plates (1) are welded to form a pouch-type separator (3), and the positive electrode leads (11) are joined to each other at weld points (31W) in a region thereof facing the separator (3).

Abstract: A type of lithium ion secondary battery is disclosed; therein, the positive electrode 1 is formed by smearing an active material on the surface of an aluminum foil body, where said active material is compound oxide(s) comprising transition metals and lithium capable of absorbing and releasing lithium ions; the negative electrode 2 is formed by smearing an active material on the surface of a copper foil body, where said active material includes carbon material capable of absorbing and releasing lithium ions. Both the positive and negative electrodes have conducting strips acting as current conductors 6, 7. The positive and negative electrodes 1, 2 are in plate form and are alternately stacked on both sides of the belt-shaped separator 3 to form the electrode core 4. The separator 3 wraps around said electrode plates and separates the positive and negative electrodes 1, 2.

Abstract: Disclosed herein is a sheet-shaped safety kit that is attached to opposite major surfaces of an electrode assembly for secondary batteries. The safety kit includes a group of metal sheets electrically connected to a cathode terminal of the electrode assembly, another group of metal sheets electrically connected to a cathode terminal of the electrode assembly, and an insulation sheet disposed between the two metal sheet groups. The metal sheets of one of the metal sheet groups are interconnected with each other at lower ends of the metal sheets, the lower-end interconnection part interconnecting the lower ends of the metal sheets has a width less than that of the metal sheets, and lower-end corners of the interconnected metal sheets are larger than lower-end corners of the metal sheets that are not interconnected with each other.

Abstract: This invention provides a lead battery that becomes usable by injecting an electrolyte thereinto. The battery includes: positive and negative electrode plates each having a grid comprising a Pb—Ca based alloy; separators that separate the positive electrode plates from the negative electrode plates; the electrolyte comprising sulfuric acid; and a battery container accommodating the positive and negative electrode plates, the separators, and the electrolyte. The battery container is sealed, and part of the positive and negative electrode plates is immersed in the electrolyte. The height Y0 of the positive and negative electrode plates and the distance Y1 from the bottom of the positive and negative electrode plates to the level of the electrolyte satisfy the relation: 15?Y1/Y0×100?60.

Abstract: An electrochemical cell comprising a cathode material contacted to a perforated current collector having a portion left uncovered and an anode material contacted to an anode current collector is described. A separator sheet segregating the anode from direct contact with the cathode is folded back upon itself along a crease with an upper portion at least partially sealed to a lower portion along an aligned peripheral edge to form an envelope. A first envelope portion houses the cathode having the uncovered portion of the cathode current collector spaced from the crease and a second envelope portion houses the anode. The first envelope portion is sealed to the second envelope portion through the uncovered perforations of the cathode current collector to lock the anode aligned with the cathode. The anode and cathode are then wound into a jellyroll electrode assembly housed in a cylindrical casing and activated with an electrolyte.

Abstract: A power disconnection apparatus includes a soft-shell Li ion battery and a power disconnection device. The soft-shell Li ion battery includes anode pin and a cathode pin and a soft shell enclosing the soft-shell Li ion battery. The power disconnection device includes a panel attaching to the surface of the shell of the soft-shell Li ion battery and a separation unit arranged at topside of the panel and corresponding to one of the anode pin and the cathode pin. The shell has expansion when the soft-shell Li ion battery is over-charged and the panel is move away from the soft-shell Li ion battery. Therefore, the separation unit disconnects power to the anode pin or the cathode pin.

Abstract: A secondary battery includes: an electrode assembly including positive and negative electrodes; a container adapted to receive the electrode assembly; a cap assembly having at least two terminals exposed outside the container, the cap assembly being adapted to be fixed to the container to seal the container; and lead elements adapted to electrically connect the terminals and the electrode assembly. A center of the terminals are aligned with a center of the electrode assembly, and the lead elements are spaced apart from the center of their respective terminals and adapted to be connected to their respective terminals and the electrode assembly.

Abstract: A lithium ion secondary battery in which an abnormal overheat due to a short circuit of a current collecting portion of one electrode and an electrode material mixture of the other is prevented. The lithium ion secondary battery has: a positive electrode including a core material having a current collecting portion and a material mixture carrying portion and a material mixture layer carried thereon; a negative electrode including a core material having a current collecting portion and a material mixture carrying portion and a material mixture layer carried thereon; a separator and a porous electron-insulating layer including an inorganic oxide filler and a binder both interposed between the positive and negative electrodes; and a non-aqueous electrolyte. The insulating layer is carried on a region including surfaces of the positive electrode current collecting portion and material mixture layer, and/or a region including surfaces of the negative electrode current collecting portion and material mixture layer.

Abstract: An electrochemical cell is provided comprising a first electrode and a second electrode. A separator, which includes an expansion joint, surrounds and seals the first electrode. The separator may comprise a first major surface and a second major surface substantially opposite the first major surface, and the expansion joint may be coupled between the first major surface and the second major surface.

Abstract: A stacked-type lithium ion battery, comprising a core, a battery shell, and a cover plate; said core is placed in the battery shell, said cover plate is coupled to the battery shell in a sealed manner; said core comprises a plurality of layers of positive plates, negative plates, and membranes that are stacked together with each other, and the membrane is between the positive plate and the negative plate; wherein at least two membranes are in a 5-175° included angle between their tensile directions. Since the tensile directions of the membranes are different, the overall tensile strengths of the battery in all tensile directions are essentially same; therefore, the phenomenon of short circuit in the battery resulted from membrane rupture in lower tensile strength directions can be prevented, and the battery safety performance is greatly enhanced.

Abstract: An electrode assembly is formed by respectively overlaying a sheet cathode 1, a sheet separator 3 and a double-sided sheet anode 8 to form a stacked structure 10, and subjecting the stacked structure to multiple folds, wherein the initial fold comprises folding the cathode in half around the double-sided anode so as to surround the respective upper and lower active anode surfaces thereof. The multiple folds may comprise one or more subsequent parallel folds made with the fold line D-D extending perpendicular to the original length of the stacked structure such that its overall length is halved at each fold. A pouch battery comprising said electrode assembly has improved safety and performance characteristics. The pouch battery construction has especial application to lithium primary batteries.

Abstract: An electrode assembly 1 for use in a soft packaged cell such as a battery or supercapacitor comprises a stack 2 of single, discrete cathode elements 4 and single, discrete anode elements 3 alternating with and abutting one another, wherein all the elements of one type are each individually encapsulated in discrete separator envelopes 7 and all the elements of the other type are uncovered, and wherein the electrode assembly 1 is sealed in soft packaging. Sensitive or delicate cathodes or anodes 13, for example, lithium anodes used in primary batteries, may be encapsulated to protect them, and this may facilitate assembly by automated handling equipment.

Abstract: A battery having flat, stacked, anode and cathode layers. The battery can be adapted to fit within an implantable medical device.

Abstract: Provided are an electrode assembly with improved active material coatings of electrodes, by which an increase in thickness or distortion in shape can be prevented even after repeated charge and discharge cycling, and a lithium ion cell having the electrode assembly.

Abstract: The separator subassembly includes a spacer layer formed from a film of microporous, non-conductive material joined to a separator by a heating process, wherein the separator is formed from an elongated piece of microporous, non-conductive film. When an anode subassembly is enveloped within the separator subassembly, the spacer aligns with a surface-mounted anode current collector of the alkali metal anode. The spacer serves as an additional protective layer between the cathode material and the anode current collector as the anode depletes.

Abstract: A battery having flat, stacked, anode and cathode layers. The battery can be adapted to fit within an implantable medical device.

Abstract: An alkaline cell having a flat housing, preferably of cuboid shape. The cell can have an anode comprising zinc and a cathode comprising MnO2. The housing can have a relatively small overall thickness, typically between about 5 and 10 mm. Cell contents can be supplied through an open end in the housing and an end cap assembly inserted therein to seal the cell. There can be a gap between separator and cathode for insertion of additional electrolyte. The end cap assembly includes a vent mechanism, preferably a grooved vent, which can activate, when gas pressure within the cell reaches a threshold level typically between about 250 and 800 psig (1724×103 and 5515×103 pascal gage). The cell can have a supplemental vent mechanism such as a laser welded region on the surface of the housing which may activate at higher pressure levels.

Abstract: An anode subassembly for use in an implantable electrochemical cell includes a solid anode current collector and an alkali metal anode pressed onto the solid anode current collector such that the solid anode current collector is located on the outer side of the outermost winding of a coiled electrode assembly formed when the anode subassembly is wound with a cathode subassembly. The anode subassembly may further include a spacer formed from a microporous, non-conductive material pressed onto the alkali metal anode on the opposite side from the solid anode current collector.

Abstract: Disclosed is a non-aqueous electrolyte battery comprising: a flat outer jacket comprising a metal sheet and having two primary flat portions facing each other; two active material layers of a first polarity respectively carried on inner surfaces of the flat portions; an electrode plate of a second polarity disposed in a position facing with each of the active material layers; and a separator layer interposed between each of the active material layers and the electrode plate of a second polarity, with the outer jacket serving as a current collector of the active material layers.

Abstract: A sealed lead-acid battery includes a separator made from hydrophilic treated sheet made from synthetic fiber which wraps at least either one of a positive electrode and a negative electrode. A mat type separator made from fine glass fiber is disposed between the wrapped electrode and its opposite electrode. This structure is adopted in a battery which uses a paste type electrode where an expanded grid having no outer frame on both edges is used, thereby prolonging cycle life even after cycling of charge and deep discharge.

Abstract: A secondary battery with a finishing tape preventing air bubbles from being formed between a jelly roll electrode structure and the finishing tape. The secondary battery includes a wound electrode assembly having a positive electrode sheet, a separator, and a negative electrode sheet, sequentially stacked, and a finishing tape having penetrating holes and adhered to the outer lateral surface of the wound electrode assembly. The penetrating holes permit air to escape, preventing the formation of air bubbles under the tape.

Abstract: The invention relates to a sleeve separator for a lead plate (2) of a lead-acid accumulator. The sleeve separator surrounds the front and rear sides and lower and bottom edges of said lead plate. The invention is characterised in that the separator material (6) on the top edge of the lead plate (2) and the sleeve is folded away from the lead plate on one side approximately at right angles, so that it projects sideways; in that the separator material (8) on the other, opposite sleeve side is also folded over the upper edge of the lead plate at right angles and also projects sideways from the side of the sleeve; and in that the two separator sections which project sideways at approximate right angles from the side of the sleeve and which are superimposed, are interconnected by a joint (7).

Abstract: A pocketed electrode plate for use in a ultra-slim lithium ion secondary battery, its manufacturing method and a lithium ion secondary battery using the same. The pocketed electrode plate comprises an electrode plate which has a coating layer of an electrode active material and a non-coated projection portion. The electrode active material can reversibly insert and extract lithium ions. The electrode plates further includes separating membranes which cover both sides of the electrode plate while exposing only the non-coated projection portion, and an insulating polymer having an adhesive component on both surfaces thereof. The insulating polymer film is placed adjacent to edges of the electrode plate but does not cover any portion of the electrode surface. The insulating polymer film is thermally bonded onto two separating membranes. A plurality of pocketed electrode plates may be produced by using a pressing roll.

Abstract: A metal-gas cell battery, such as a zinc-air cell battery, has one or more metal-gas cells. Each metal-gas cell has a metal anode sandwiched between a pair of gas cathodes. Each gas cathode is disposed within a rigid retaining structure. An expandable soft pocket for holding an electrolyte connects the two retaining structures. The anode is disposed within the soft pocket without being enclosing by a separator bag. The cell is mechanically refueled by expanding the soft pocket to allow replacing easily a spent anode with a fresh anode.

Abstract: A stacked lithium-ion rechargeable battery comprises a plurality of stacked positive and negative electrode couples forming a battery core, each of said couple having a negative electrode, a positive electrode, a separator, and non-aqueous electrolyte, all encased in a battery case. The core is secured by a clamp case and said clamp case is encased in a battery shell. There are thin neck parts (or conducting tabs) extending from the base plates of the positive and negative electrodes to form the current collectors of the positive and negative electrodes. The positive electrodes and negative electrodes are arranged such that the two current collectors are located on the two opposite ends of the core. The current collector at each end of the core is clamped by a clip and connecting to the respective positive and negative terminals. This stacked lithium-ion rechargeable battery has a relatively low impedance, high discharge rate and high safety performance.

Abstract: An alkaline storage battery having excellent self-discharge characteristics even after a number of charge-discharge cycles is provided. The alkaline storage battery is provided with a case and an electrode group enclosed in the case, and a separator that is included in the electrode group retains at least 15 mg/cm2 of an electrolyte at least in a period after assembling the battery, from the time the separator is impregnated with the electrolyte to the time the battery is activated.

Abstract: Battery with a flexible laminate casing includes a means for fixing the electrode assembly (2) within the casing (1, 18). The fixing means may be a frame (19, 33, 38, 50, 54) attached to the periphery of the electrode assembly, or an insulating spacer (59, 69, 70, 77, 78) encased within the casing together with the electrode assembly such as to fill a space between one end of the electrode assembly and the casing. Alternatively, the fixing means may be constructed of a material with which the casing and the electrode assembly are joined together by applying heat and pressure, or may be an abutting surface (87h) provided to the casing (87) itself such as to make contact with one end face of the electrode assembly within the casing.

Abstract: A square shaped battery includes: an electrode plate group including a belt-like positive electrode plate, a belt-like negative electrode plate, and a belt-like separator, the belt-like positive electrode plate, the belt-like negative electrode plate, and the belt-like separator being laminated and rolled up to form the electrode plate group; and a pair of power collectors disposed on sides of the electrode plate group for collecting electric power from the electrode plate group.