Electric storage device

Abstract

An electricity storage element is provided with: an electrode body in which an electrode plate and a separator are laminated; an electrolyte; a container that accommodates the electrode body and the electrolyte; and a sheet-like porous body that is disposed between the electrode body and the container, has insulating properties, and has a through-hole formed in the electrode plate, and the air permeability of the porous body is lower than the air permeability of the separator.

Description

Technical Field

[0001] The present invention relates to an electric storage element in which an electrode body and an electrolyte solution are accommodated in a container. Background Art

[0002] Conventionally, a storage element having an electrode body in which a plate and a separator are stacked, an electrolyte, and a container for containing the electrode body and the electrolyte is widely known. For example, Patent Document 1 discloses a wound-type storage device (storage element) in which a positive electrode plate and a negative electrode plate are stacked and wound with a separator interposed therebetween, and an electrolyte is contained in a battery container.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-210031 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In an energy storage element, a structure that allows an electrolyte to easily penetrate into an electrode body is desired. In the energy storage element disclosed in the above-mentioned patent document 1, a plurality of ventilation paths are formed in the electrode body, and it is assumed that the electrolyte can easily penetrate into the electrode body through the ventilation paths. However, in such an energy storage element, in order to insulate the electrode body from the container, an insulating sheet is sometimes arranged between the electrode body and the container. In this case, when vacuuming or injecting the electrolyte into the container, the insulating sheet may block the passage of the electrolyte. As a result, the insulating sheet hinders the penetration of the electrolyte into the electrode body, and the electrolyte may have difficulty penetrating into the electrode body.

[0008] The present invention was made by the inventors of the present application with new attention paid to the above-mentioned problems, and an object of the present invention is to provide an electric storage element capable of insulating an electrode body from a container and allowing an electrolyte solution to easily penetrate into the electrode body.

[0009] Means for solving problems

[0010] A storage element according to one embodiment of the present invention comprises: an electrode body formed by stacking electrode plates and separators; an electrolyte; a container that accommodates the electrode body and the electrolyte; and a sheet-like porous body that is arranged between the electrode body and the container and has insulating properties, wherein through holes are formed in the electrode plates, and the air permeability of the porous body is lower than that of the separator.

[0011] Effects of the Invention

[0012] According to the electric storage device of the present invention, the electrode body and the container can be insulated and the electrolyte can be easily permeated into the electrode body. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing the appearance of the electric storage element according to the embodiment.

[0014] Figure 2 This is an exploded perspective view showing each component by disassembling the power storage device according to the embodiment.

[0015] Figure 3 It is a perspective view showing the structure of an electrode body according to the embodiment.

[0016] Figure 4 It is a perspective view and a cross-sectional view showing the structure of the electrode body according to the embodiment.

[0017] Figure 5 It is a front view and a cross-sectional view which show the structure of the through hole of the electrode body which concerns on embodiment.

[0018] Figure 6 It is a front view and a cross-sectional view showing the structure of the through hole of the electrode body according to Modification 1 of the embodiment. DETAILED DESCRIPTION

[0019] (1) A storage element according to one embodiment of the present invention comprises: an electrode body formed by stacking electrode plates and separators; an electrolyte; a container that contains the electrode body and the electrolyte; and a sheet-like porous body that is arranged between the electrode body and the container and has insulating properties, wherein through holes are formed in the electrode plates, and the air permeability of the porous body is lower than that of the separator.

[0020] According to a storage element of one embodiment of the present invention, in the storage element, an insulating sheet-like member (insulating sheet) is arranged between an electrode body formed by stacking a plate and a separator and a container, a through hole is formed in the plate, and the insulating sheet is set as a porous body, and the air permeability of the porous body is lower than that of the separator. In this way, by forming a through hole in the plate of the electrode body, the through hole can be made into a passage for the electrolyte, so that the electrolyte can easily penetrate into the electrode body. However, if an insulating sheet is arranged between the electrode body and the container, there is a risk that the insulating sheet blocks the passage of the electrolyte to the electrode body when vacuuming or injecting the electrolyte into the container, so that the electrolyte is difficult to penetrate into the electrode body. Therefore, the insulating sheet is made into a porous body, and the air permeability of the porous body is lower than that of the separator. As a result, the electrolyte can pass through the porous body relatively easily, so the electrolyte can easily penetrate into the electrode body. In this way, in the electric storage element, the electrolyte can penetrate into the electrode body through the porous body and the through-holes of the electrode plate. Therefore, the electrolyte can easily penetrate into the electrode body while insulating the electrode body from the container.

[0021] (2) In the energy storage device described in (1) above, the porous body may have an air permeability of 250 sec / 100 mL or less.

[0022] According to the electricity storage device described in (2) above, since the air permeability of the porous body is reduced to 250 sec / 100 mL or less, the electrolyte solution can pass through the porous body relatively easily.

[0023] (3) In the electric storage device described in (1) or (2) above, the porous body may be disposed between the container and the through hole.

[0024] When the porous body is disposed between the container and the through hole of the electrode body, the porous body may be in close contact with the through hole due to deformation of the container when the electrolyte is injected into the container and evacuation is performed. According to the storage element described in (3) above, even in this case, the electrolyte can pass through the porous body by reducing the air permeability of the porous body, thereby preventing the passage of the electrolyte to the electrode body from being blocked.

[0025] (4) In the electric storage element described in any one of (1) to (3) above, the electrode plate may include a positive electrode plate and a negative electrode plate, and the positive electrode plate and the negative electrode plate are respectively provided with a plurality of positive electrode through holes and a plurality of negative electrode through holes as the through holes, and the plurality of positive electrode through holes and the plurality of negative electrode through holes are arranged at overlapping positions when viewed from the through direction of the through holes.

[0026] According to the storage element described in (4) above, a plurality of positive electrode through holes and a plurality of negative electrode through holes are formed in the positive electrode plate and the negative electrode plate, and the plurality of positive electrode through holes and the plurality of negative electrode through holes are arranged at overlapping positions when viewed from the through direction of the through holes. Thus, the plurality of positive electrode through holes and the plurality of negative electrode through holes can be made into passages for the electrolyte, so that the electrolyte can more easily penetrate into the electrode body.

[0027] (5) In the electric storage device according to any one of (1) to (4), the electrode body may be formed by winding the electrode plates, and the container may have a liquid injection portion for the electrolyte in a wall portion extending along a winding axis direction of the electrode body.

[0028] According to the storage element described in (5) above, the storage element has the following structure: the electrode body is a winding type, and an electrolyte injection portion is provided on a wall portion extending along the winding axis direction of the electrode body in the container, so that when the electrolyte is injected into the container, it is difficult for the electrolyte to penetrate from the outside to the inside of the electrode body. In this way, the storage element has a structure in which it is difficult for the electrolyte to penetrate into the electrode body, and the effect brought about by adopting the structure of the present application is obvious.

[0029] (6) In the energy storage device according to any one of (1) to (5) above, the porous body may be formed of a nonwoven fabric.

[0030] According to the electric storage device described in (6), by forming the porous body from nonwoven fabric, a thin, high-strength and inexpensive porous body can be produced. The porous body can be easily arranged by simply placing the nonwoven fabric between the electrode body and the container.

[0031] (7) In the electric storage device according to any one of (1) to (6), the electrode body may be formed by winding the electrode plate, and the separator may have an inorganic coating layer containing inorganic particles.

[0032] According to the storage element described in (7) above, when the electrolyte is injected into the container of the storage element, it is difficult for the electrolyte to penetrate from the outside to the inside of the electrode body in the wound electrode body, and it is difficult for the electrolyte to penetrate into the electrode body. However, by coating the separator with an inorganic coating, the permeability of the electrolyte to the separator can be improved.

[0033] (8) In the electric storage device described in any one of (1) to (7) above, a length of the electrode body in the winding axis direction is 500 mm or more.

[0034] In the case of a long wound electrode body with a length of 500 mm or more in the winding axis direction, it becomes more difficult to make the electrolyte penetrate into the electrode body, but according to the storage element described in (8) above, by coating the separator with an inorganic coating, the effect of improving the permeability of the electrolyte into the separator becomes significant. According to this method, the penetration time of the electrolyte into the electrode body can be shortened, so that the electrolyte can easily penetrate into the electrode body.

[0035] (9) In the electric storage element according to any one of (1) to (8), the electrolyte permeation area of ​​the inorganic coating layer at 300 seconds after the electrolyte is dripped is 80 mm 2 above.

[0036] The electric storage device according to (9) above, wherein the inorganic coating layer of the separator has an electrolyte penetration area of ​​80 mm at 300 seconds after the electrolyte is dropped. 2 The electrolyte can penetrate into the inorganic coating layer with a relatively wide area in a relatively short time. Thus, by using the inorganic coating layer with a relatively wide area in a relatively short time, the permeability of the electrolyte to the separator can be improved.

[0037] (10) In the electric storage device according to any one of (1) to (9) above, the inorganic coating layer may include at least one of barium sulfate and aluminum oxide as the inorganic particles.

[0038] The inventors of the present application have found that when an electrolyte is dripped into an inorganic coating layer containing at least one of barium sulfate and aluminum oxide, the electrolyte can penetrate into a relatively wide area of ​​the inorganic coating layer in a relatively short time. According to the storage element described in (10) above, the permeability of the electrolyte to the separator can be improved by making the inorganic coating layer of the separator contain at least one of barium sulfate and aluminum oxide.

[0039] Hereinafter, the storage element of the embodiment of the present invention (including its modified example) is described with reference to the accompanying drawings. The embodiments described below all represent general or specific examples. The numerical values, shapes, materials, components, configuration positions of components and connection methods, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples and are not intended to limit the present invention. In each figure, dimensions, etc. are not strictly illustrated. In each figure, the same or identical components are marked with the same figure mark.

[0040] In the following description and drawings, the arrangement direction of a pair of terminals (positive and negative, the same below) of the storage element, the arrangement direction of a pair of collectors, the winding axis direction of the electrode body, the extension direction of the electrode body, or the opposite direction of the short side of the container is defined as the X-axis direction. The opposite direction of the long side of the container or the thickness direction of the container is defined as the Y-axis direction. The arrangement direction or the up-down direction of the container body and the cover of the container is defined as the Z-axis direction. These X-axis directions, Y-axis directions, and Z-axis directions are directions that intersect each other (orthogonal in this embodiment). Depending on the usage, the situation where the Z-axis direction is not the up-down direction is also considered, but for the sake of convenience of explanation below, the Z-axis direction is described as the up-down direction.

[0041] In the following description, the positive direction of the X-axis indicates the direction of the arrow of the X-axis, and the negative direction of the X-axis indicates the direction opposite to the positive direction of the X-axis. When simply referred to as the X-axis direction, it indicates both directions or the direction of either one of the positive direction of the X-axis and the negative direction of the X-axis. When referred to as one side and the other side of the X-axis direction, it indicates one side and the other side of the positive direction of the X-axis and the negative direction of the X-axis. The same applies to the Y-axis direction and the Z-axis direction. Expressions such as parallel and orthogonal that indicate relative directions or postures strictly speaking also include situations where they are not the directions or postures. For example, two directions being parallel not only means that the two directions are completely parallel, but also means that they are substantially parallel, that is, for example, containing a difference of about a few percent. In the following description, when expressed as "insulation", it means "electrical insulation".

[0042] (Implementation Method)

[0043] [1. Overall Description of the Electricity Storage Element 10]

[0044] First, use Figure 1 and Figure 2 , the energy storage element 10 of this embodiment will be fully described. Figure 1 It is a perspective view showing the appearance of the energy storage device 10 according to the present embodiment. Figure 2 FIG. 1 is an exploded perspective view showing the components of the energy storage device 10 according to the present embodiment after being disassembled. Figure 2 In FIG. 8 , the porous body 800 is indicated by a dotted line, and the structure of the electrode body 700 is shown in a manner that the porous body 800 is seen through.

[0045] The storage element 10 is a secondary battery (single cell) that can be charged and discharged, more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The storage element 10 is used as a battery for driving or starting an engine of a mobile body such as a car, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, or a railway vehicle for an electric railway. As the above-mentioned car, an electric car (EV), a hybrid electric car (HEV), a plug-in hybrid electric car (PHEV), and a fossil fuel (gasoline, light oil, liquefied natural gas, etc.) car can be exemplified. As the railway vehicle for the above-mentioned electric railway, a tram, a monorail, a maglev train, and a hybrid electric car with both a diesel engine and an electric motor can be exemplified. The storage element 10 can also be used as a fixed battery used in a home or business.

[0046] The storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The storage element 10 may also be a primary battery that can use the stored electricity even if the user does not charge it, rather than a secondary battery. The storage element 10 may also be a bag-type storage element. In the present embodiment, a storage element 10 having a rectangular parallelepiped shape (square) flattened in the Y-axis direction is illustrated, but the shape of the storage element 10 is not limited to a rectangular parallelepiped shape, and may also be a polygonal prism shape, a long cylindrical shape, an elliptical cylindrical shape, or a cylindrical shape other than a rectangular parallelepiped.

[0047] like Figure 1 As shown, the energy storage device 10 includes a container 100, a pair of (positive and negative) terminals 300, and a pair of (positive and negative) upper gaskets 400. Figure 2 As shown, a pair of (positive electrode and negative electrode) lower gaskets 500, a pair of (positive electrode and negative electrode) current collectors 600, an electrode body 700 and a porous body 800 are housed inside the container 100. In addition to the above-mentioned components, a spacer or the like may be arranged on the side or below the electrode body 700 or the porous body 800.

[0048] An electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but the illustration is omitted. As the electrolyte, there is no particular restriction on its type as long as it does not damage the performance of the storage element 10, and various electrolytes can be selected. The electrolyte contains a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. As a non-aqueous solvent, it can be appropriately selected from known non-aqueous solvents. As a non-aqueous solvent, cyclic carbonates such as ethylene carbonate (EC) or propylene carbonate (PC), chain carbonates such as ethyl methyl carbonate (EMC), carboxylates, phosphates, sulfonates, ethers, amides, nitriles, etc. can be cited. As a non-aqueous solvent, a solvent in which a part of the hydrogen atoms contained in these compounds are replaced by halogens can be used. As an electrolyte salt, it can be appropriately selected from known electrolyte salts. As an electrolyte salt, lithium salts such as inorganic lithium salts such as LiPF6, sodium salts, potassium salts, magnesium salts, onium salts, etc. can be cited. Among them, lithium salts are preferred. In addition to non-aqueous solvents and electrolyte salts, the electrolyte may also contain additives such as biphenyl.

[0049] The container 100 is a rectangular parallelepiped (square or box-shaped) shell having a container body 110 and a cover 120, wherein the container body 110 has an opening formed on the positive Z-axis direction side, and the cover 120 closes the opening of the container body 110. The cover 120 is a flat and rectangular member constituting the cover of the container 100, and is arranged in the positive Z-axis direction of the container body 110. The cover 120 is a wall extending in the winding axis direction of the electrode body 700. The winding axis direction of the electrode body 700 refers to the direction in which the winding axis L of the electrode body 700 described later extends (the direction along the winding axis L, in this embodiment, the X-axis direction).

[0050] The container body 110 is a rectangular cylindrical member having a bottom that constitutes the main body of the container 100. The container body 110 has a pair of long side walls 111 on the surfaces (sides) on both sides in the Y-axis direction, a pair of short side walls 112 on the surfaces (sides) on both sides in the X-axis direction, and a bottom wall 113 on the surface (bottom) in the negative Z-axis direction. The long side wall 111 is a flat and rectangular wall extending in the X-axis direction (winding axis direction of the electrode body 700), forming the long side of the container 100. The long side wall 111 is adjacent to the short side wall 112, the bottom wall 113, and the cover 120, and has a larger area than the short side wall 112. The short side wall 112 is a flat and rectangular wall extending in the Z-axis direction, forming the short side of the container 100. The short side wall portion 112 is adjacent to the long side wall portion 111, the bottom wall portion 113, and the cover 120, and has a smaller area than the long side wall portion 111. The bottom wall portion 113 is a flat and rectangular wall portion extending in the X-axis direction (the winding axis direction of the electrode body 700), and forms the bottom surface of the container 100. The bottom wall portion 113 is arranged adjacent to the long side wall portion 111 and the short side wall portion 112.

[0051] After the electrode body 700 and the porous body 800 are housed inside the container body 110, the container body 110 is joined to the cover body 120 by welding or the like, and the inside of the container 100 is sealed. The material of the container 100 (the container body 110 and the cover body 120) is not particularly limited, and can be a metal that can be welded (joined) such as stainless steel, aluminum, aluminum alloy, iron, plated steel plate, etc., but resin can also be used. The container body 110 and the cover body 120 can be formed of the same material or different materials. In the case where the storage element 10 is a bag-type storage element, the container 100 can also be a laminated film composed of multiple layers including a metal layer and a resin layer.

[0052] The container 100 is provided with a liquid injection portion 130 and a gas discharge valve 140. In the present embodiment, the liquid injection portion 130 is formed on the long side wall portion 111 of the container body 110, and the gas discharge valve 140 is formed on the cover 120. That is, the liquid injection portion 130 and the gas discharge valve 140 are formed on a wall portion (different wall portions in the present embodiment) extending in the winding axis direction (X-axis direction) of the electrode body 700. The gas discharge valve 140 is a safety valve that releases the pressure when the pressure inside the container 100 rises excessively. In the present embodiment, the gas discharge valve 140 is arranged at the center portion in the X-axis direction and the center portion in the Y-axis direction of the cover 120, but may be arranged at any position of the cover 120.

[0053] The liquid injection part 130 is a part (liquid injection part of the electrolyte) for injecting the electrolyte into the inner side of the container 100 when manufacturing the storage element 10. The liquid injection part 130 is used to evacuate the container 100, inject the electrolyte into the container 100 to impregnate the electrode body 700 with the electrolyte, or degas the gas from the electrode body 700 when manufacturing the storage element 10. In the present embodiment, the liquid injection part 130 is arranged at the end in the positive direction of the Z axis and the center in the X axis direction of the long side wall part 111 in the negative direction of the Y axis of the container body 110.

[0054] The liquid injection part 130 includes a liquid injection port 131 and a liquid injection plug 132. The liquid injection port 131 is a through hole formed in the container 100 for injecting electrolyte into the inside of the container 100. In the present embodiment, the liquid injection port 131 is a through hole, for example, in a circular shape, arranged at the end of the long side wall portion 111 in the positive direction of the Z axis and the center of the X axis direction of the container body 110 of the container 100 in the negative direction of the Y axis. The liquid injection plug 132 is a member that blocks the liquid injection port 131. Specifically, the liquid injection plug 132 is a blocking member (lid member) that is joined to the long side wall portion 111 to block the liquid injection port 131 after the container 100 is evacuated from the liquid injection port 131 and the electrolyte is injected into the inside of the container 100 when the storage element 10 is manufactured. The material of the liquid injection plug 132 is not particularly limited, and any metal that can be used in the container 100 (container body 110) can be used. In particular, the liquid injection plug 132 is preferably formed of a material that can be welded to the container body 110 , such as the same material as the container body 110 .

[0055] The terminal 300 is a terminal member (positive terminal and negative terminal) electrically connected to the electrode body 700 via the collector 600. That is, the terminal 300 is a metal member for conducting electricity stored in the electrode body 700 to the external space of the storage element 10 and for introducing electricity into the internal space of the storage element 10 in order to store electricity in the electrode body 700. The terminal 300 is formed of a conductive member of a metal such as aluminum, aluminum alloy, copper or copper alloy. The terminal 300 is connected (joined) to the collector 600 by riveting or welding, and is mounted on the cover 120. The terminal 300 is configured in a state protruding from the outer surface (the surface in the positive direction of the Z axis) of the cover 120 in the positive direction of the Z axis. In the present embodiment, the terminal 300 is a welding terminal joined to an external conductive member such as a bus bar by welding, but the terminal 300 may also be a bolt terminal having a bolt portion having an external threaded portion protruding in the positive direction of the Z axis and joined to the conductive member by bolting.

[0056] The current collector 600 is arranged on both sides of the electrode body 700 in the X-axis direction, and is a conductive current collector member (positive electrode current collector and negative electrode current collector) that is connected (joined) to the electrode body 700 and the terminal 300 to electrically connect the electrode body 700 and the terminal 300. The current collector 600 is connected (joined) to the end 720 of the electrode body 700 described later by welding or riveting, and is fixed to the cover 120 by riveting or welding as described above. The material of the current collector 600 is not particularly limited. In the present embodiment, the positive electrode current collector 600 is formed of aluminum or an aluminum alloy, etc., like the positive electrode current collector foil 741 of the electrode body 700 described later, and the negative electrode current collector 600 is formed of copper or a copper alloy, etc., like the negative electrode current collector foil 751 of the electrode body 700 described later.

[0057] The upper gasket 400 is a plate-shaped and rectangular gasket disposed between the cover 120 and the terminal 300 of the container 100 to insulate and seal the cover 120 and the terminal 300. The lower gasket 500 is a plate-shaped and rectangular gasket disposed between the cover 120 and the collector 600 to insulate the cover 120 and the collector 600. The upper gasket 400 and the lower gasket 500 are formed of insulating members such as polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyetheretherketone (PEEK), tetrafluoroethylene-perfluoroalkylvinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyamide (PA), ABS resin, or composite materials thereof.

[0058] The electrode body 700 is a storage element (power generation element) that is formed by stacking electrode plates (positive electrode plates 740 and negative electrode plates 750 described later) and separators (separator 760 described later) and is capable of storing electricity. In the present embodiment, the electrode body 700 is formed by winding the electrode plates and separators. The electrode body 700 is in the shape of an elongated strip extending in the X-axis direction and has an oblong shape (long cylindrical shape) when viewed from the X-axis direction. The electrode body 700 has an electrode body main body 710 and end portions 720 protruding from the electrode body main body 710 on both sides in the X-axis direction. As described above, the end portions 720 are connected (joined) to the collector 600. A through hole 730 is formed in the electrode body main body 710. A detailed description of the structure of the electrode body 700 will be described later.

[0059] The porous body 800 is an insulating sheet-like member (insulating sheet, insulating film) disposed between the electrode body 700 and the container 100. The porous body 800 encloses the electrode body 700 and the collector 600 to ensure the insulation between the container 100 and the electrode body 700 and the collector 600. In order to ensure insulation, the porous body 800 preferably has a resistance of 1MΩ or more when 100V is applied. In the present embodiment, the porous body 800 is an insulating sheet with a bottom rectangular tube configured in a manner covering both sides of the electrode body 700 and the collector 600 in the X-axis direction, both sides of the Y-axis direction, and the negative direction of the Z-axis. That is, the porous body 800 is disposed between a pair of long side walls 111, a pair of short side walls 112, and a bottom wall 113 of the container 100 and the electrode body 700 and the collector 600 to ensure the insulation between the container 100 and the electrode body 700 and the collector 600.

[0060] The porous body 800 is disposed on both sides of the electrode body 700 in the Y-axis direction in a state of contact with the container 100 (long side wall portion 111) and the electrode body 700 (see Figure 5The porous body 800 is disposed between the container 100 (long side wall portion 111 ) and the through hole 730 in the negative direction of the Y axis of the electrode body 700 (see Figure 5 ). The porous body 800 is preferably arranged between at least a portion of the periphery of the through hole 730 and the container 100, but in the present embodiment, it is arranged between the through hole 730 and the entire periphery of the through hole 730 and the container 100 in a manner covering the entire through hole 730. Specifically, the porous body 800 is arranged in a state of contact with the entire periphery of the through hole 730 and the long side wall portion 111 of the container 100. Furthermore, the porous body 800 is arranged between the liquid injection portion 130 provided in the long side wall portion 111 and the electrode body 700. Specifically, the porous body 800 is arranged in a state of contact with the entire periphery of the liquid injection port 131 formed in the long side wall portion 111 and the electrode body 700. In this way, the porous body 800 is arranged between the liquid injection portion 130 and the through hole 730 (the passage of the electrolyte from the liquid injection portion 130 to the through hole 730).

[0061] The porous body 800 is arranged near the short side wall portion 112 of the container 100 or in contact with the short side wall portion 112 on both sides of the electrode body 700 in the X-axis direction. The porous body 800 is arranged near the bottom wall portion 113 of the container 100 or in contact with the bottom wall portion 113 in the negative direction of the Z-axis of the electrode body 700. Thus, the porous body 800 absorbs the excess electrolyte accumulated in the lower part of the container 100. The porous body 800 may be in contact with the electrode body 700 (or the collector 600) on both sides of the electrode body 700 in the X-axis direction and in the negative direction of the Z-axis, or may be arranged separately from the electrode body 700 (or the collector 600).

[0062] The air permeability of the porous body 800 is lower than the air permeability of the later-described separator 760 possessed by the electrode body 700. The porous body 800 is formed with pores (100 μm or more) larger than the pores of the separator 760. The air permeability is also called the Gurley value, which indicates the number of seconds for a certain volume of air to pass through an object of a certain area based on a certain pressure difference, and is a value measured in accordance with JIS-P8117 (2009). Generally speaking, for the air permeability of the separator 760, when the thickness is 30 μm, it is about 540 seconds / 100 mL, when the thickness is 20 μm, it is about 270 seconds / 100 mL, and when the thickness is 20 μm and a ceramic coating is applied, it is about 300 seconds / 100 mL. Therefore, the air permeability of the porous body 800 is preferably less than 250 seconds / 100 mL. In the present embodiment, the air permeability of the separator 760 is 300 seconds / 100 mL.

[0063] The porous body 800 is formed of a non-woven fabric. In the present embodiment, the porous body 800 is a porous body of a polyolefin such as PP (polypropylene), specifically, it is formed of a polymer non-woven fabric made of PP. The air permeability of the PP non-woven fabric is about 10 to 100 seconds / 100 mL. Therefore, the air permeability of the porous body 800 is more preferably less than 100 seconds / 100 mL. The porous body 800 can be formed of other non-woven fabrics such as glass fiber non-woven fabrics, can also be formed of a foam (PP foam sheet, etc.), and can also be formed of an elastomer, etc. The air permeability of glass fiber non-woven fabric (glass fiber paper 100μm) is about 4 seconds / 100mL. The air permeability of the PP foam sheet (continuous pores) is about 10 to 20 seconds / 100mL. Therefore, the air permeability of the porous body 800 is further preferably less than 20 seconds / 100mL.

[0064] [Description of the Structure of the Second Electrode Body 700]

[0065] Next, the structure of the electrode body 700 will be described in detail. Figure 3 It is a perspective view showing the structure of an electrode body 700 according to the present embodiment. Figure 3 The structure of the electrode body 700 is shown in a state where the electrode plates in the electrode body 700 are partially unfolded. Figure 4 It is a perspective view and a cross-sectional view showing the structure of the electrode body 700 of this embodiment. Figure 4 (a) is a perspective view showing the structure of the electrode body 700 after the electrode plates are wound. Figure 4 (b) is a cross-sectional view showing a stacked state of electrode plates by enlarging a portion of the cross section of the electrode body 700 .

[0066] [2.1 Overall Description of Electrode Body 700]

[0067] like Figure 3 and Figure 4 As shown, the electrode body 700 includes a positive electrode plate 740 and a negative electrode plate 750 as two electrode plates, and includes separators 761 and 762 as two separators 760 .

[0068] The positive electrode plate 740 is a plate (electrode plate) in which a positive electrode active material layer 742 is formed on the surface of a long strip-shaped current collector foil (metal foil) made of a metal such as aluminum or an aluminum alloy, that is, a positive electrode current collector foil 741. The negative electrode plate 750 is a plate (electrode plate) in which a negative electrode active material layer 752 is formed on the surface of a long strip-shaped current collector foil (metal foil) made of a metal such as copper or a copper alloy, that is, a negative electrode current collector foil 751. As the positive electrode current collector foil 741 and the negative electrode current collector foil 751, a known material can be used as long as it is a material that is stable to the redox reaction during charging and discharging, such as nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, Al-Cd alloy, etc. Known materials can be used as appropriate. As the positive electrode active material used in the positive electrode active material layer 742 and the negative electrode active material used in the negative electrode active material layer 752, known materials can be used as long as they are positive electrode active materials and negative electrode active materials that can absorb and release lithium ions.

[0069] As the positive electrode active material, polyanion compounds such as LiMPO4, LiMSiO4, LiMBO3 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, LiMn2O4 or LiMn 1.5 Ni 0.5 O4 and other spinel lithium manganese oxides, LiMO2 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) and other lithium transition metal oxides. As negative electrode active materials, in addition to lithium metal, lithium alloys (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium and Wood's alloy containing lithium metal), alloys capable of absorbing and releasing lithium, carbon materials (graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature sintered carbon, amorphous carbon, etc.), silicon oxides, metal oxides, lithium metal oxides (Li4Ti5O 12 etc.), polyphosphate compounds, or compounds of transition metals and elements of Groups 14 to 16, such as Co3O4 or Fe2P, which are commonly referred to as conversion negative electrodes.

[0070] The separator 760 (separators 761 and 762) is a microporous insulating sheet made of resin or the like. As a material for the separator 760, a known material can be used appropriately as long as the performance of the storage element 10 is not impaired. As a form of the separator 760, woven fabric, non-woven fabric, porous resin film, etc. can be cited. Among these forms, porous resin film is preferred from the viewpoint of strength, and non-woven fabric is preferred from the viewpoint of electrolyte retention. As a material for the separator 760, polyolefins such as polyethylene and polypropylene are preferred from the viewpoint of shutdown function, and polyimide, aromatic polyamide, etc. are preferred from the viewpoint of resistance to oxidative decomposition. As the separator 760, a material obtained by compounding these resins can also be used. The separators 761 and 762 can be formed of the same material or different materials.

[0071] The electrode body 700 is formed by alternately stacking and winding the positive electrode plates 740 and the negative electrode plates 750 of the above structure and the separators 761 and 762. That is, the electrode body 700 is formed by stacking and winding the positive electrode plates 740, the separators 761, the negative electrode plates 750 and the separators 762 in this order (see Figure 4 (b) etc.). In the present embodiment, the electrode body 700 is a wound electrode body formed by winding the positive electrode plate 740 and the negative electrode plate 750 around a winding axis L extending in the X-axis direction. The winding axis L is a virtual axis that becomes the central axis when the positive electrode plate 740 and the negative electrode plate 750 are wound, and in the present embodiment, it is a straight line that passes through the center of the electrode body 700 and is parallel to the X-axis direction.

[0072] Specifically, in the electrode body 700, the positive electrode plate 740 and the negative electrode plate 750 are wound with the separators 761 and 762 interposed therebetween in the direction along the winding axis L (winding axis direction, in this embodiment, the X-axis direction). The positive electrode plate 740 and the negative electrode plate 750 have portions (active material layer non-formed portions) where the positive electrode active material layer 742 and the negative electrode active material layer 752 are not formed (coated) and the positive electrode collector foil 741 and the negative electrode collector foil 751 are exposed at the ends of the respective staggered directions. Thus, the electrode body 700 has a positive electrode end 720 where the active material layer non-formed portions of the positive electrode plates 740 are stacked and bundled at one end in the winding axis direction, and has a negative electrode end 720 where the active material layer non-formed portions of the negative electrode plates 750 are stacked and bundled at the other end in the winding axis direction.

[0073] The end portion 720 is a portion where the positive electrode plate 740 or the negative electrode plate 750 is stacked in the stacking direction (Y-axis direction). That is, the electrode body 700 has an electrode body main body 710 constituting the main body of the electrode body 700 and a pair of (positive and negative) end portions 720 protruding from the electrode body main body 710 to both sides in the X-axis direction. The electrode body main body 710 is a long cylindrical portion (active material layer forming portion) formed by winding the portion of the positive electrode plate 740 and the negative electrode plate 750 where the positive electrode active material layer 742 and the negative electrode active material layer 752 are formed (coated) with the separators 761 and 762. Thus, the electrode body main body 710 has a pair of curved portions 711 on both sides in the Z-axis direction and a pair of flat portions 712 on both sides in the Y-axis direction (refer to Figure 4 That is, the electrode body 700 includes a curved portion 711 formed by winding the positive electrode plate 740 and the negative electrode plate 750 around a winding axis L and a flat portion 712 .

[0074] The curved portion 711 is a curved portion extending in the X-axis direction and curved in a semicircular arc shape in a manner protruding in the Z-axis direction when viewed from the X-axis direction, and is arranged opposite to the bottom wall portion 113 and the cover body 120 of the container body 110. That is, the pair of curved portions 711 are curved portions protruding in both sides of the Z-axis direction toward the bottom wall portion 113 and the cover body 120 of the container body 110 when viewed from the X-axis direction. The flat portion 712 is a rectangular and flat portion extending in parallel with the XZ plane toward the Y-axis direction, connecting the ends of the pair of curved portions 711, and is arranged opposite to the long side wall portions 111 on both sides of the Y-axis direction of the container body 110. The curved shape of the curved portion 711 is not limited to a semicircular arc shape, and may be a part of an elliptical shape, etc., and may be curved arbitrarily. The flat portion 712 is not limited to a flat surface facing the Y-axis direction, and the outer surface may be slightly concave or slightly bulging.

[0075] With the above structure, the electrode body 700 has a long (horizontally long) shape with a relatively long length in the winding axis direction (X-axis direction). In the present embodiment, the electrode body 700 has a shape extending in the X-axis direction of about 300 mm, specifically, about 500 mm to 1500 mm. The length of the electrode body 700 in the X-axis direction is not particularly limited, and may be shorter than 300 mm or longer than 1500 mm. Furthermore, one or more through holes 730 are formed in the electrode body 700. That is, one or more through holes 730 are formed in the electrode plates (positive electrode plate 740 and negative electrode plate 750) of the electrode body 700. In the present embodiment, a plurality of (six) through holes 730 are formed in the electrode body main body 710 of the electrode body 700. Hereinafter, the term “through hole” is also used. Figure 5 The structure of the through hole 730 will be described in detail.

[0076] [2.2 Description of Through Hole 730]

[0077] Figure 5 1 and 2 are a front view and a cross-sectional view showing the structure of a through hole 730 of an electrode body 700 according to the present embodiment. Figure 5 (a) is a front view showing the structure of the through hole 730 of the electrode body 700 when viewed from the front (positive direction of the Y axis). Figure 5 (b) means Figure 5 (a) is a cross-sectional view of a section. Figure 5 In order to also show the positional relationship between the electrode body 700 (through hole 730), the porous body 800, and the long side wall portion 111 of the container body 110 of the container 100, the porous body 800 and the long side wall portion 111 are also shown. The plurality of (six) through holes 730 formed in the electrode body 700 have the same structure, and therefore, in Figure 5 In the figure, one through hole 730 is shown, and one through hole 730 is described in detail.

[0078] like Figure 2~Figure 4 As shown, the through hole 730 is formed in the center of the flat portion 712 in the negative direction of the Y axis of the electrode body main body 710 in the X axis direction and the end in the positive direction of the Z axis. That is, the through hole 730 is arranged at a position opposite to the long side wall portion 111 in the negative direction of the Y axis of the container body 110 of the container 100 and close to the injection portion 130. In this embodiment, in the electrode body main body 710, six through holes 730 are arranged at a predetermined interval in the winding axis direction (X axis direction). The distance between two adjacent through holes 730, or the distance between the end edge of the electrode body 700 in the winding axis direction (X axis direction) and the through hole 730 closest to the end edge is 100 mm or more and 300 mm or less. For example, when the length of the electrode body 700 in the X axis direction is about 1400 mm, the six through holes 730 are arranged at intervals of about 200 mm.

[0079] like Figure 4 (b) and Figure 5As shown, the portion of the positive electrode plate 740 where the positive electrode active material layer 742 is formed (coated) on the positive electrode current collector foil 741 is referred to as the positive electrode active material portion 743. The portion of the negative electrode plate 750 where the negative electrode active material layer 752 is formed (coated) on the negative electrode current collector foil 751 is referred to as the negative electrode active material portion 753. That is, the positive electrode current collector foil 741 and the positive electrode active material layer 742 excluding the portion included in the end 720 of the positive electrode are referred to as the positive electrode active material portion 743, and the negative electrode current collector foil 751 and the negative electrode active material layer 752 excluding the portion included in the end 720 of the negative electrode are referred to as the negative electrode active material portion 753. In other words, the portion of the positive electrode plate 740 other than the positive electrode collector foil 741 included in the positive electrode end 720 is called the positive electrode active material portion 743 , and the portion of the negative electrode plate 750 other than the negative electrode collector foil 751 included in the negative electrode end 720 is called the negative electrode active material portion 753 .

[0080] Specifically, in Figure 4 (b) and Figure 5 In the figure, the three layers of the positive electrode active material layer 742 (two layers) formed on both sides of the positive electrode current collector foil 741 (one layer) in the positive electrode plate 740 of the electrode body 700 are referred to as one positive electrode active material portion 743. The three layers of the negative electrode active material layer 752 (two layers) formed on both sides of the negative electrode current collector foil 751 (one layer) in the negative electrode plate 750 of the electrode body 700 are referred to as one negative electrode active material portion 753. That is, by winding the positive electrode plate 740 and the negative electrode plate 750, a plurality of positive electrode active material portions 743 and a plurality of negative electrode active material portions 753 are stacked in a state where the separators 761 and 762 are arranged between the positive electrode active material portions 743 and the negative electrode active material portions 753. The electrode body main body 710 is formed by stacking the plurality of positive electrode active material portions 743, the plurality of negative electrode active material portions 753, and the separators 761 and 762.

[0081] The through hole 730 is formed in at least one of the positive active material portion 743 and the negative active material portion 753 located in the flat portion 712 of the electrode body 710. In this embodiment, the through hole 730 is formed in both the positive active material portion 743 and the negative active material portion 753 and the separators 761 and 762.

[0082] Specifically, if Figure 5As shown, a positive electrode through hole 743a as a through hole 730 is formed in the positive electrode active material portion 743. The positive electrode through hole 743a is a circular through hole that penetrates the positive electrode active material portion 743 in the Y-axis direction. That is, the positive electrode through hole 743a is a circular through hole that penetrates the positive electrode collector foil 741 and the two positive electrode active material layers 742 provided on both sides of the positive electrode collector foil 741 in the Y-axis direction. A negative electrode through hole 753a as a through hole 730 is formed in the negative electrode active material portion 753. The negative electrode through hole 753a is a circular through hole that penetrates the negative electrode active material portion 753 in the Y-axis direction. That is, the negative electrode through-hole 753 a is a circular through-hole that penetrates the negative electrode current collector foil 751 and two negative electrode active material layers 752 provided on both surfaces of the negative electrode current collector foil 751 in the Y-axis direction.

[0083] When viewed from the through direction of the through hole 730 (the arrangement direction of the positive through hole 743a and the negative through hole 753a, the Y-axis direction), the positive through hole 743a and the negative through hole 753a are arranged at a position where at least a portion of them overlap. In this embodiment, when viewed from the Y-axis direction, the negative through hole 753a is arranged at a position where it completely overlaps with the positive through hole 743a. That is, when viewed from the Y-axis direction, the negative through hole 753a has a shape smaller than the positive through hole 743a and is arranged on the inner side of the positive through hole 743a.

[0084] From the viewpoint of suppressing the reduction of the capacity of the storage element 10, the size of the positive electrode through hole 743a and the negative electrode through hole 753a is as small as possible. However, if it is too small, it becomes difficult to process the hole portion, or it is difficult to remove the electrode plate of the hole portion after processing. Therefore, it is preferable that the size is not too small. Specifically, the positive electrode through hole 743a and the negative electrode through hole 753a (through hole 730) are preferably 0.8 mm or more in diameter (opening area is 0.5 mm 2 More preferably, the diameter is 1 mm or more (the opening area is 0.785 mm 2 In this embodiment, the negative electrode through hole 753a is a circular through hole with a diameter (diameter, the same below) of about 0.8mm to 3mm, and the positive electrode through hole 743a is a circular through hole with a diameter of about 1.5mm to 5mm. In this way, one or more through holes 730 include an opening area of ​​0.5mm 2 In this embodiment, the opening area of ​​all the positive electrode through holes 743 a and the negative electrode through holes 753 a (through holes 730 ) is 0.5 mm 2 Above (diameter is 0.8mm or more).

[0085] The positive electrode through hole 743a and the negative electrode through hole 753a can be formed by laser-based processing (laser welding, laser cutting) before winding the positive electrode plate 740 and the negative electrode plate 750. The positive electrode through hole 743a can be formed by forming (coating) the positive electrode active material layer 742 on the positive electrode collector foil 741 with the through hole formed in advance, or by punching the positive electrode collector foil 741 and the positive electrode active material layer 742 after forming (coating) the positive electrode active material layer 742 on the positive electrode collector foil 741. The same is true for the negative electrode through hole 753a. The positive electrode through hole 743a and the negative electrode through hole 753a can also be formed by stamping, but in order to process the small hole at high speed, it is preferably formed by laser-based processing.

[0086] In the present embodiment, by winding the positive electrode plate 740 and the negative electrode plate 750, a plurality of positive electrode active material portions 743 and a plurality of negative electrode active material portions 753 are stacked in the stacking direction. The plurality of positive electrode active material portions 743 and the plurality of negative electrode active material portions 753 are stacked in a direction orthogonal to the flat surface of the flat portion 712 (i.e., the Y-axis direction). At this time, a plurality of positive electrode through holes 743a and a plurality of negative electrode through holes 753a arranged continuously in the stacking direction are formed in the plurality of positive electrode active material portions 743 and the plurality of negative electrode active material portions 753. That is, a plurality of positive electrode through holes 743a and a plurality of negative electrode through holes 753a as through holes 730 are formed in the positive electrode plate 740 and the negative electrode plate 750, respectively. The plurality of positive electrode through holes 743a and the plurality of negative electrode through holes 753a are arranged at overlapping positions when viewed from the through direction of the through hole 730. In this embodiment, the through holes 730 (a plurality of positive electrode through holes 743 a and a plurality of negative electrode through holes 753 a ) are formed in the flat portion 712 , so the through direction of the through holes 730 (the stacking direction of the plurality of positive electrode active material portions 743 and the plurality of negative electrode active material portions 753 ) can be defined as the Y-axis direction.

[0087] The plurality of positive electrode through holes 743a are formed so that the spacing increases from the positive electrode active material portion 743 located in the innermost layer (innermost periphery) of the electrode body 700 toward the positive electrode active material portion 743 located in the outermost layer (outermost periphery) so that the plurality of positive electrode through holes 743a are aligned in position after the positive electrode plate 740 and the negative electrode plate 750 are wound. The same is true for the negative electrode through holes 753a.

[0088] The through holes 730 are also formed in the active material parts arranged in the outermost layer (outermost periphery) among the plurality of positive active material parts 743 and the plurality of negative active material parts 753. When the negative active material part 753 is arranged in the outermost layer (outermost periphery) of the electrode body 700, the negative through holes 753a are also formed in the outermost negative active material part 753. Thus, in the electrode body 700, the plurality of positive through holes 743a and the plurality of negative through holes 753a are continuously formed from the active material part in the outermost layer (outermost periphery) to the active material part in the innermost layer (innermost periphery) of the electrode body 700. That is, when viewed from the Y-axis direction, all the negative through holes 753a formed in the plurality of negative active material parts 753 are arranged inside all the positive through holes 743a formed in the plurality of positive active material parts 743.

[0089] The partition plate 761 is formed with a partition plate through hole 761a as the through hole 730. The partition plate through hole 761a is a circular through hole that penetrates the partition plate 761 in the Y-axis direction. The partition plate through hole 762a is formed with a partition plate through hole 730. The partition plate through hole 762a is a circular through hole that penetrates the partition plate 762 in the Y-axis direction. In the present embodiment, the partition plate through holes 761a and 762a are through holes of the same shape and size, but they may be through holes of different shapes or sizes.

[0090] When viewed from the through-hole 730's through-hole direction (the arrangement direction of the positive electrode through-hole 743a and the negative electrode through-hole 753a, the Y-axis direction), the separator through-holes 761a and 762a are arranged at positions where at least a portion overlaps with the positive electrode through-hole 743a and the negative electrode through-hole 753a. In the present embodiment, when viewed from the Y-axis direction, the separator through-holes 761a and 762a are arranged at positions where all overlap with the positive electrode through-hole 743a and a portion overlaps with the negative electrode through-hole 753a. That is, when viewed from the Y-axis direction, the separator through-holes 761a and 762a have a shape that is smaller than the positive electrode through-hole 743a and larger than the negative electrode through-hole 753a, and are arranged on the inner side of the positive electrode through-hole 743a, and the negative electrode through-hole 753a is arranged on the inner side. The partition through holes 761a and 762a are circular through holes with a diameter of about 1 mm to 4 mm.

[0091] The separator through holes 761a and 762a can be formed by laser processing or stamping before winding the positive electrode plate 740 and the negative electrode plate 750, similarly to the positive electrode through hole 743a and the negative electrode through hole 753a. The separator through holes 761a and 762a can also be processed by irradiating the positions of the positive electrode through hole 743a and the negative electrode through hole 753a with laser after winding the positive electrode plate 740 and the negative electrode plate 750. In this case, the separator through holes 761a and 762a can also be through holes of the same size as the negative electrode through hole 753a, or a size smaller than the negative electrode through hole 753a.

[0092] Thus, on the separators 761 and 762, a plurality of separator through-holes 761a and 762a are continuously formed in the Y-axis direction together with a plurality of positive electrode through-holes 743a and a plurality of negative electrode through-holes 753a. That is, a plurality of separator through-holes 761a and 762a are continuously formed from the separator 761 or 762 located at the outermost layer (outermost periphery) of the electrode body 700 to the separator 761 or 762 located at the innermost layer (innermost periphery). Thus, in the electrode body 700, when viewed from the Y-axis direction, all the separator through-holes 761a and 762a formed in the separators 761 and 762 are arranged inside all the positive electrode through-holes 743a.

[0093] By forming the through hole 730 in the electrode body 700, the effective electrode area of ​​the electrode body 700 is reduced, and the capacity of the storage element 10 is reduced (capacity loss occurs). The effective electrode area of ​​the electrode body 700 is the area of ​​the region where the active material layer is arranged in the electrode plate (specifically, the region where the positive electrode active material layer 742 is arranged in the positive electrode plate 740). The ratio of the reduction in the effective electrode area is called the opening area ratio. The opening area ratio is the ratio of the total opening area of ​​one or more through holes 730 located in the region where the active material layer is arranged in the electrode plate to the area of ​​the region. Specifically, the opening area ratio is the ratio of the total opening area of ​​the positive through holes 743a located in the region where the positive electrode active material layer 742 is arranged in the positive electrode plate 740 to the area of ​​the region. Specifically, the opening area ratio is the ratio of the total opening area of ​​the positive electrode through holes 743a located in the region where the positive electrode active material layer 742 is arranged to the area of ​​the region when the positive electrode sheet 740 is expanded by unfolding the wound state of the electrode body 700 and looking down on the positive electrode sheet 740.

[0094] From the viewpoint of suppressing the reduction in the capacity of the storage element 10, the opening area ratio is preferably 3% or less, more preferably less than 0.1%, and further preferably less than 0.05%. As described above, the opening area ratio can also be said to be the ratio of the capacity reduction (capacity loss) of the storage element 10 caused by the through hole 730. Therefore, the ratio of the capacity reduction (capacity loss) of the storage element 10 is also preferably 3% or less, more preferably less than 0.1%, and further preferably less than 0.05%.

[0095] In the present embodiment, the separator 762 is disposed at the outermost layer (outermost periphery) of the electrode body 700, so that the separator 762 is in contact with the porous body 800. The separator 762 may not be disposed at the outermost layer (outermost periphery) of the electrode body 700. In this case, the negative electrode plate 750 (the outermost negative electrode active material portion 753) is disposed at the outermost layer (outermost periphery) of the electrode body 700, so that the negative electrode plate 750 (the negative electrode active material portion 753) is in contact with the porous body 800.

[0096] [3. Description of the Effect]

[0097] As described above, according to the electric storage element 10 of the embodiment of the present invention, a sheet-like member (insulating sheet) having insulating properties is arranged between the electrode body 700 formed by stacking the electrode plates (positive electrode plate 740, negative electrode plate 750) and the separator 760, and the through hole 730 is formed in the electrode plate. The insulating sheet is set as a porous body 800, and the air permeability of the porous body 800 is set lower than the air permeability of the separator 760. In this way, by forming the through hole 730 in the electrode plate of the electrode body 700, the through hole 730 can be made into a passage of the electrolyte, so that the electrolyte easily penetrates into the electrode body 700. However, if the insulating sheet is arranged between the electrode body 700 and the container 100, when the electrolyte is injected into the container 100, the insulating sheet blocks the passage of the electrolyte to the electrode body 700, and it is possible that the electrolyte is difficult to penetrate into the electrode body 700. Therefore, the insulating sheet is made into a porous body 800, and the air permeability of the porous body 800 is made lower than the air permeability of the separator 760 (the air permeability is improved). As a result, the electrolyte can pass through the porous body 800 relatively easily, so the electrolyte can easily penetrate into the electrode body 700. In this way, in the energy storage element 10, the electrolyte can penetrate into the electrode body 700 through the porous body 800 and the through-hole 730 of the electrode plate, so that the electrolyte can easily penetrate into the electrode body 700 while insulating the electrode body 700 from the container 100.

[0098] When the electrolyte solution permeates the electrode body 700 for a long time, the copper of the negative electrode plate 750 may be dissolved and a short circuit may occur. However, by making the electrolyte solution permeate the electrode body 700 easily and shortening the permeation time of the electrolyte solution into the electrode body 700, the occurrence of the short circuit can be suppressed. Since the remaining electrolyte solution can also be accumulated in the pores of the porous body 800 and the through-holes 730, it is possible to suppress the situation where the electrolyte solution is consumed due to the reduction of the electrolyte solution during charging and discharging (SEI film formation) and the electrolyte shortage. In particular, by configuring the porous body 800 near the bottom wall portion 113 of the container 100 or in contact with the bottom wall portion 113, the remaining electrolyte solution accumulated in the lower part of the container 100 can be accumulated in the pores of the porous body 800. When the gas is discharged from the gas discharge valve 140 to the outside of the storage element 10, the gas in the electrode body 700 can be easily discharged through the through-holes 730 and the pores of the porous body 800. In particular, if the porous body 800 is formed of a material that shrinks due to heat (polyolefin, etc.), the porous body 800 shrinks due to the heat of the gas (about 300 to 600° C.) when the gas is discharged, and the gas passage can be expanded. By forming the through hole 730 in the flat portion 712 of the electrode body main body 710 of the electrode body 700, the through hole 730 is easily formed.

[0099] When using an electrode body 700 that is long in the winding axis direction, it becomes more difficult to make the electrolyte penetrate into the electrode body 700. Therefore, when using such a long electrode body 700, the effect brought by adopting the structure of the present application is significant.

[0100] By reducing the air permeability of the porous body 800 to 250 seconds / 100 mL or less (improving air permeability), the electrolyte can pass through the porous body 800 relatively easily. Generally speaking, the air permeability of the separator 760 is about 270 seconds to 540 seconds / 100 mL, so by reducing the air permeability of the porous body 800 to 250 seconds / 100 mL or less, the electrolyte can pass through the porous body 800 relatively easily.

[0101] When the porous body 800 is disposed between the container 100 and the through hole 730 of the electrode body 700, when the container 100 is injected with electrolyte and vacuum is drawn, the porous body 800 and the through hole 730 are sometimes closely attached due to deformation of the container 100. In this case, by reducing the air permeability of the porous body 800, the electrolyte can pass through the porous body 800, so that the passage of the electrolyte to the electrode body 700 can be suppressed from being blocked. In particular, when the storage element 10 is a bag-type storage element and the container 100 is a laminated film, the container 100 is deformed and the porous body 800 is easily in close contact with the through hole 730, so the effect brought by adopting the structure of the present application is obvious.

[0102] A plurality of positive through holes 743a and a plurality of negative through holes 753a are formed in the positive electrode plate 740 and the negative electrode plate 750, and the plurality of positive through holes 743a and the plurality of negative through holes 753a are arranged at overlapping positions when viewed from the through direction of the through hole 730. Thus, the plurality of positive through holes 743a and the plurality of negative through holes 753a can be made into passages for the electrolyte, so that the electrolyte can more easily penetrate into the electrode body 700.

[0103] The storage element 10 has the following structure: the electrode body 700 is a winding type, and the wall portion (long side wall portion 111) extending along the winding axis direction of the electrode body 700 in the container 100 is provided with an electrolyte injection portion 130, so when the electrolyte is injected into the container 100, the electrolyte is difficult to penetrate from the outside to the inside of the electrode body 700. In this way, the storage element 10 has a structure in which the electrolyte is difficult to penetrate into the electrode body 700, so the effect brought by adopting the structure of the present application is obvious. In particular, the injection portion 130 (injection port 131) is provided on the long side wall portion 111 of the container 100, so when the electrolyte is injected into the container 100 and the vacuum is drawn from the injection port 131, there is a situation where the porous body 800 is closely attached to the injection port 131 of the long side wall portion 111. In this case, since the air permeability of the porous body 800 is reduced, the electrolyte solution can pass through the porous body 800 , and thus it is possible to suppress the passage of the electrolyte solution to the electrode body 700 from being blocked.

[0104] By forming the porous body 800 from a nonwoven fabric, it is possible to produce a thin, high-strength, and inexpensive porous body 800. The nonwoven fabric can be placed between the electrode body 700 and the container 100, so the porous body 800 can be easily placed. In particular, the porous body 800 can be placed by a simple operation such as winding the nonwoven fabric around the electrode body 700, so the porous body 800 can be easily placed between the electrode body 700 and the container 100.

[0105] Since the porous body 800 is arranged to cover the entire electrode body 700 , the above-mentioned effect can be achieved over the entire electrode body 700 .

[0106] [4. Description of Modifications]

[0107] Although the electric storage element 10 according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. The embodiment disclosed herein is illustrative in all respects, and the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

[0108] (Variant 1)

[0109] In the above embodiment, the resin may be applied to or infiltrated into the positive electrode active material layer 742 around the positive electrode through-hole 743 a of the through-hole 730 of the electrode body 700 . Figure 6 1 and 2 are a front view and a cross-sectional view showing the structure of a through hole 730 of an electrode body 700 according to Modification 1 of the present embodiment. Figure 6 is with Figure 5 The corresponding figure.

[0110] like Figure 6 As shown, in this modification, when viewed from the Y-axis direction, the positive electrode through hole 743a is formed to have the same size as the negative electrode through hole 753a, and the positive electrode active material layer 742 around the positive electrode through hole 743a is provided with an insulating portion 744. That is, the positive electrode plate 740 has an insulating portion 744, and the insulating portion 744 is arranged around the positive electrode through hole 743a and the size of the outer periphery 744a thereof is larger than that of the negative electrode through hole 753a. The other structures of this modification are the same as those of the above-mentioned embodiment, so detailed description is omitted.

[0111] The insulating portion 744 is a portion where the positive electrode active material layer 742 around the positive electrode through hole 743a is masked by dissolving an insulating member such as a resin. That is, the insulating portion 744 is a portion where the content of insulating materials such as resin is greater than that of other portions in the positive electrode active material layer 742. The insulating portion 744 can be formed by dissolving a UV-curable epoxy resin that is cured by irradiating ultraviolet rays into the positive electrode active material layer 742, or by dissolving a polyolefin resin such as PE, PP, etc. that is melted by heating. The insulating portion 744 can be easily formed by pressing a resin molding die to allow the resin to flow in. The insulating portion 744 can also be formed by arranging an adhesive modified polyolefin sheet (a sheet member that introduces polar groups into polyolefin to give adhesion to heterogeneous materials) pre-formed into a shape covering the surrounding of the positive electrode through hole 743a on the positive electrode active material layer 742 around the positive electrode through hole 743a, heating, melting, and infiltration. When the insulating material such as the resin permeates into the positive electrode active material layer 742 , the positive electrode active material layer 742 is deactivated (the discharge capacity is reduced).

[0112] As described above, according to the storage element 10 of this modification, the same effect as that of the above-mentioned embodiment can be achieved. In particular, in the case where the positive electrode plate 740 and the negative electrode plate 750 are formed with the positive electrode through hole 743a and the negative electrode through hole 753a, it is preferable to have a structure in which the negative electrode active material layer 752 covers the positive electrode active material layer 742 regardless of the size of the positive electrode through hole 743a and the negative electrode through hole 753a. Therefore, an insulating portion 744 having an outer periphery 744a larger in size than the negative electrode through hole 753a is arranged around the positive electrode through hole 743a in the positive electrode plate 740. Thus, even in the case where the positive electrode through hole 743a is the same size as the negative electrode through hole 753a or smaller than the negative electrode through hole 753a (the same size in this modification), the positive electrode active material layer 742 can be covered by the negative electrode active material layer 752. That is, by inactivating the positive electrode active material layer 742 around the positive electrode through-hole 743 a , the activated positive electrode active material layer 742 can be covered with the negative electrode active material layer 752 , and lithium electrodeposition on the negative electrode plate 750 can be suppressed.

[0113] In this modification, when viewed from the Y-axis direction, the positive electrode through hole 743a may be smaller or larger than the negative electrode through hole 753a, and the size of the outer periphery 744a of the insulating portion 744 may be larger than the negative electrode through hole 753a. The separator through holes 761a and 762a may be the same size as the negative electrode through hole 753a and the positive electrode through hole 743a, or smaller than the negative electrode through hole 753a and the positive electrode through hole 743a.

[0114] (Other variations)

[0115] In the above embodiment, the porous body 800 is configured to cover both sides of the electrode body 700 and the collector 600 in the X-axis direction, both sides of the Y-axis direction, and the negative direction of the Z-axis, but the configuration position and size of the porous body 800 are not particularly limited. The porous body 800 can cover the positive direction of the Z-axis of the electrode body 700 and the collector 600. The porous body 800 may not cover both sides of the X-axis direction of the electrode body 700 and the collector 600, but cover both sides of the Y-axis direction of the electrode body 700 and the collector 600 and the negative direction of the Z-axis, and is a U-shaped insulating sheet when viewed from the X-axis direction. The porous body 800 may only cover a portion of the electrode body 700 and the collector 600 in the Y-axis direction, or only cover a portion of the negative direction of the Z-axis. The porous body 800 may also only cover a single side of the electrode body 700 and the collector 600 in the Y-axis direction. In this way, the porous body 800 may not cover both sides of the electrode body 700 and the current collector 600 in the X-axis direction, both sides of the Y-axis direction, and a part of the negative Z-axis direction. That is, the porous body 800 only needs to be arranged between the electrode body 700 and the container 100, and may not be arranged between the liquid injection part 130 and the through hole 730, between the container 100 and the through hole 730, or between the liquid injection part 130 and the electrode body 700.

[0116] In the above embodiment, the air permeability of the porous body 800 is 250 seconds / 100 mL or less, but the air permeability may be lower than that of the separator 760 of the electrode body 700, and the air permeability of the porous body 800 may be greater than 250 seconds / 100 mL. If the porous body 800 is made of a material with a lower air permeability than the separator 760, it may not be formed of the above materials such as non-woven fabrics, but may be formed of any material.

[0117] In the above embodiment, the liquid injection portion 130 is arranged at the positive end of the long side wall portion 111 in the negative direction of the Y axis and the center in the X axis direction of the container body 110 of the container 100, but the arrangement position of the liquid injection portion 130 is not limited. The liquid injection portion 130 can be arranged at the end of the long side wall portion 111 in the X axis direction, or at the center of the Z axis direction or the end of the negative direction of the Z axis. The liquid injection portion 130 can also be arranged at the long side wall portion 111 in the positive direction of the Y axis. The liquid injection portion 130 can be arranged at the lid 120 of the container 100, or at the bottom wall portion 113 of the container body 110. That is, the liquid injection portion 130 only needs to be arranged at the wall portion extending in the winding axis direction of the electrode body 700. Alternatively, the liquid injection portion 130 can also be arranged at the short side wall portion 112 of the container body 110. The gas discharge valve 140 is arranged at the lid 120, but can also be arranged at any wall portion of the container body 110.

[0118] In the above embodiment, the through hole 730 of the electrode body 700 is formed at the positive Z-axis end of the flat portion 712 in the negative Y-axis direction of the electrode body main body 710, but it can also be formed at any position of the electrode body 700. The through hole 730 can also be formed in the Z-axis center or the negative Z-axis end of the flat portion 712. The through hole 730 can be formed in the flat portion 712 in the positive Y-axis direction of the electrode body main body 710, and can also be formed in the curved portion 711 of the electrode body main body 710. If the through hole 730 is formed in the curved portion 711, the through hole 730 is not easily blocked by the container 100, so it is easy for the electrolyte to penetrate into the electrode body 700. If the through hole 730 is formed at the lower part (the end in the negative direction of the Z axis) of the electrode body 700, the through hole 730 can be arranged at a position close to the bottom wall 113 of the container 100, so that the electrolyte accumulated in the lower part of the container 100 can be easily infiltrated into the electrode body 700. In particular, when the amount of electrolyte in the container 100 is small (such as at the end of life), the electrolyte accumulated in the lower part of the container 100 can also be infiltrated into the electrode body 700. By forming the through hole 730 at the lower part of the electrode body 700, the excess electrolyte accumulated in the lower part of the container 100 can also be accumulated in the through hole 730.

[0119] In the above embodiment, six through holes 730 are formed in the electrode body 700, but the number of through holes 730 is not particularly limited, and may be a plurality other than six, or may be one. The configuration position of the through hole 730 is also not particularly limited, and a plurality of through holes 730 may be arranged in a direction intersecting the X-axis direction, or a plurality of through holes 730 may be randomly configured. In the case where the length of the electrode body 700 in the X-axis direction is further lengthened, it is preferred to further form through holes 730 at different positions in the X-axis direction of the electrode body 700. In the case where the length of the electrode body 700 in the Z-axis direction is lengthened, it is preferred to further form through holes 730 at different positions in the Z-axis direction of the electrode body 700. Thus, the electrolyte can easily penetrate into the electrode body 700.

[0120] In the above embodiment, through holes 730 (positive through holes 743a and negative through holes 753a) are formed in all of the stacked multiple positive active material parts 743 and multiple negative active material parts 753, but this is not limited to this. Through holes 730 may not be formed in any positive active material part 743 or any negative active material part 753. Similarly, with respect to the separators 761 and 762, there may be a portion where the through holes 730 (separator through holes 761a and 762a) are not formed between the outermost separators 761 and 762 and the innermost separators 761 and 762 in the electrode body 700.

[0121] In the above embodiment, through holes 730 (positive electrode through holes 743a and negative electrode through holes 753a) are formed in both the positive electrode active material portion 743 and the negative electrode active material portion 753, but the present invention is not limited thereto. Through holes 730 may be formed in only one of the positive electrode active material portion 743 and the negative electrode active material portion 753. The same is true for the separators 761 and 762. Through holes 730 (separator through holes 761a and 762a) may be formed in only one of the separators 761 and 762, or through holes 730 may not be formed in both the separators 761 and 762.

[0122] In the above embodiment, when viewed from the Y-axis direction, the negative electrode through hole 753a has a shape smaller than the positive electrode through hole 743a and is arranged on the inner side of the positive electrode through hole 743a, but it is not limited to this. The negative electrode through hole 753a may not be arranged on the inner side of the positive electrode through hole 743a, but may be arranged at a slightly deviated position, or may be arranged at a position that does not overlap with the positive electrode through hole 743a. The shape, size relationship and arrangement position of the positive electrode through hole 743a and the negative electrode through hole 753a are not particularly limited. However, even in this case, it is preferred that there is no portion in the positive electrode active material layer 742 (active positive electrode active material layer 742) that is not opposite to the negative electrode active material layer 752. That is, it is preferred that the entire positive electrode active material layer 742 (active positive electrode active material layer 742) is opposite to the negative electrode active material layer 752. The separator through holes 761a and 762a can also be arranged at a position slightly offset from the positive electrode through hole 743a and the negative electrode through hole 753a, or at a position that does not overlap with the positive electrode through hole 743a and the negative electrode through hole 753a. That is, the shape, size relationship and arrangement position of the separator through holes 761a and 762a and the positive electrode through hole 743a and the negative electrode through hole 753a are not particularly limited. However, even in this case, it is preferred that the positive electrode active material layer 742 (active positive electrode active material layer 742) is completely opposite to the separators 761 and 762.

[0123] In the above embodiment, an inorganic coating may also be provided on the partition 760 (partitions 761, 762). The inorganic coating is a coating applied (coated) to the partition. Specifically, the inorganic coating is a coating comprising inorganic particles and an adhesive (adhesive material), and the inorganic coating can be applied (coated) to the entire or a portion of the surface (one side or both sides) of the partition 760 using the adhesive. As the adhesive, a known material can be used appropriately. The inorganic coating preferably comprises at least one of aluminum silicate, barium sulfate and aluminum oxide (boehmite) as inorganic particles, and particularly preferably comprises at least one of barium sulfate and aluminum oxide. The electrolyte penetration area of ​​the inorganic coating at 300 seconds after the electrolyte is added dropwise is preferably 80 mm 2 More than 90 mm is more preferred 2Above. The method for determining the penetration area is as follows. The evaluation sample is placed on a glass plate in a manner that the surface becomes a coating and the back becomes a partition 760, and 0.3cc of electrolyte is dripped onto the center of the sample. When the electrolyte is attached to the organic or inorganic coating, it is set to 0 seconds, and the portion that changes color due to the penetration of the liquid at the 300th second is regarded as the penetration range. When the electrolyte dripped onto the inorganic coating is expanded into a circular shape, the diameter of the penetration range is measured at three locations, and the area of ​​the circle calculated based on the average value of the diameter is used as the penetration area. In the case where it is visually confirmed that the extended shape of the electrolyte is a non-circular deformed shape such as an elliptical shape, the portion that changes color due to the penetration of the liquid is regarded as the penetration range, and image processing is performed to calculate the penetration area. As the electrolyte, propylene carbonate (PC) is used. The larger the particle size of the inorganic particles, the faster the penetration rate, so the average primary particle size of the inorganic substance (inorganic particles) is preferably 1μm or more, and more preferably 3μm or more. The particle size of the inorganic substance (inorganic particles) is less than the thickness of the inorganic coating 760b. The inorganic coating layer may be thicker than the separator 760 (the separators 761 and 762 ). However, when the inorganic coating layer covers one surface of the separator 760 (the separators 761 and 762 ) and is thinner than the separator substrate, it is preferable in that the thickness of the separator 760 can be reduced.

[0124] When the separator 760 (separators 761, 762) is provided with an inorganic coating and the through hole 730 is formed in the electrode body 700, the electrolyte can be infiltrated into the electrode body 700 through the through hole 730 from the separator 760 whose permeability of the electrolyte is improved by the inorganic coating, so that the electrolyte can be infiltrated into the electrode body 700 in a further shorter time. Therefore, it is more preferable to form the through hole 730 in the electrode body 700.

[0125] The longer the length of the electrode body 700 (the length from one end edge to the other end edge in the winding axis direction (X-axis direction) of the electrode body 700), the more difficult it is for the electrolyte to penetrate into the electrode body 700, so the effect of forming an inorganic coating on the separator 760 can be obtained. Therefore, the length of the electrode body 700 is 500 mm or more, preferably longer than 500 mm, more preferably 550 mm or more, and further preferably 600 mm or more. The length of the electrode body main body 710 is 500 mm or more, preferably longer than 500 mm, more preferably 550 mm or more, and further preferably 600 mm or more.

[0126] From the perspective of effectively permeating the electrolyte, when the electrode body 700 does not form the through hole 730, the length of the electrode body 700 (or the length of the electrode body main body 710) is preferably 800 mm or less, and more preferably 700 mm or less. When the electrode body 700 is formed with a through hole 730, the length of the electrode body 700 (or the length of the electrode body main body 710) is preferably 1600 mm or less, and more preferably 1400 mm or less. That is, when the electrode body 700 does not form the through hole 730, the length of the electrode body 700 (or the length of the electrode body main body 710) is preferably 500 mm or more and 800 mm or less, more preferably longer than 500 mm and 800 mm or less, more preferably 550 mm or more and 700 mm or less, and particularly preferably 600 mm or more and 700 mm or less. When the electrode body 700 is formed with a through hole 730, the length of the electrode body 700 (or the length of the electrode body main body 710) is preferably greater than 500 mm and less than 1600 mm, more preferably longer than 500 mm and less than 1600 mm, further preferably greater than 550 mm and less than 1400 mm, and particularly preferably greater than 600 mm and less than 1400 mm.

[0127] As described above, by coating the separator 760 with an inorganic coating, the permeability (liquid wettability and capillary force) of the electrolyte to the separator 760 can be improved. Therefore, the penetration time of the electrolyte to the electrode body 700 can be shortened, so that the electrolyte can easily penetrate into the electrode body 700. When the penetration time of the electrolyte to the electrode body 700 is long, the copper of the negative electrode plate 750 may be dissolved and a short circuit may occur, but since the penetration time of the electrolyte to the electrode body 700 can be shortened, the occurrence of the short circuit can be suppressed. Specifically, if the penetration of the electrolyte to the electrode body 700 takes more than 6 hours, the copper of the negative electrode plate 750 may be dissolved and a short circuit may occur, but by coating the separator 760 with an inorganic coating, the occurrence of the short circuit can be suppressed.

[0128] In the above embodiment, the pair of terminals 300 are both arranged to protrude from the container 100 in the positive direction of the Z axis, but the protruding direction of the terminals 300 is not particularly limited. The pair of terminals 300 may protrude from the container 100 in either direction of the X axis or in both directions of the X axis.

[0129] In the above embodiment, the electrode body 700 is an elongated cylindrical shape (flat shape) having a curved portion 711 and a flat portion 712, but it may also be a cylindrical shape or an elliptical cylindrical shape, etc. In the electrode body 700, the end 720 may also be a pole ear portion (a portion where a plurality of pole ears of a pole plate are stacked) protruding from a portion of the electrode body main body 710. In the above embodiment, the electrode body 700 is a wound electrode body in which the winding axis L is parallel to the cover body 120, but it may also be a wound electrode body in which the winding axis L is perpendicular to the cover body 120. The electrode body 700 may be a stacked (stacked) electrode body formed by stacking a plurality of flat plate-shaped pole plates and separators, or a corrugated electrode body in which the pole plates are folded into a corrugated shape, etc. The electrode body 700 may also not be in a long strip shape along the X-axis direction.

[0130] A configuration in which the components included in the above-described embodiment and its modified examples are arbitrarily combined is also within the scope of the present invention.

[0131] Industrial Applicability

[0132] The present invention can be applied to power storage devices such as lithium ion secondary batteries.

[0133] Description of reference numerals:

[0134] 10 Storage Components

[0135] 100 Containers

[0136] 110 Container body

[0137] 111 Long side wall

[0138] 120 Cover

[0139] 130 Liquid injection part

[0140] 131 Liquid injection port

[0141] 132 Liquid injection plug

[0142] 140 Gas exhaust valve

[0143] 300 terminal

[0144] 600 Current Collector

[0145] 700 Electrode body

[0146] 710 Electrode body

[0147] 711 Bend

[0148] 712 Flat part

[0149] 720 end

[0150] 730 Through hole

[0151] 740 positive plate

[0152] 741 Positive electrode collector foil

[0153] 742 positive electrode active material layer

[0154] 743 Positive electrode active material

[0155] 743a Positive electrode through hole

[0156] 744 Insulation

[0157] 744a Peripheral

[0158] 750 Negative Plate

[0159] 751 Negative electrode collector foil

[0160] 752 Negative electrode active material layer

[0161] 753 Negative electrode active material

[0162] 753a Negative electrode through hole

[0163] 760, 761, 762 Partition

[0164] 761a, 762a Partition plate through hole

[0165] 800 Porous bodies.

Claims

1. A power storage element, wherein: The power storage element comprises: The electrode body is formed by laminating the electrode plates and the separators; Electrolyte; a container that accommodates the electrode body and the electrolyte; and a sheet-like porous body, which is disposed between the electrode body and the container and has insulating properties, The electrode plate has through holes formed therein, and the air permeability of the porous body is lower than that of the separator.

2. The electric storage element according to claim 1, wherein The porous body has an air permeability of 250 sec / 100 mL or less.

3. The electric storage element according to claim 1 or 2, wherein: The porous body is disposed between the container and the through hole.

4. The electric storage element according to claim 1 or 2, wherein: The electrode plate comprises a positive electrode plate and a negative electrode plate. The positive electrode plate and the negative electrode plate are respectively formed with a plurality of positive electrode through holes and a plurality of negative electrode through holes as the through holes. The plurality of positive electrode through holes and the plurality of negative electrode through holes are arranged at overlapping positions when viewed from a penetration direction of the through holes.

5. The electric storage element according to claim 1 or 2, wherein: The electrode body is formed by winding the electrode plate, The container has a liquid injection portion for the electrolyte in a wall portion extending in a winding axis direction of the electrode body.

6. The electric storage element according to claim 1 or 2, wherein: The porous body is formed of a nonwoven fabric.

7. The electric storage element according to claim 1 or 2, wherein: The electrode body is formed by winding the electrode plate, The separator has an inorganic coating layer including inorganic particles.

8. The electric storage element according to claim 7, wherein The length of the electrode body in the winding axis direction is 500 mm or more.

9. The electric storage element according to claim 7, wherein The penetration area of ​​the electrolyte at 300 seconds after the inorganic coating was dripped with the electrolyte was 80 mm 2 above.

10. The electric storage element according to claim 7, wherein The inorganic coating layer includes at least one of barium sulfate and aluminum oxide as the inorganic particles.

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