JP2022116686A - Power storage element and manufacturing method of the same - Google Patents

Abstract

To provide a power storage element which enables improvement of reliability.SOLUTION: A power storage element 10 includes an electrode body 700 in which polar plates (positive electrode plates 740 and negative electrode plates 750) are wound. The electrode body 700 has: a body part 710; multiple tab parts 720, of which a pair protrudes from each of both end surfaces as seen in a wound axis direction (an X axis direction) in the body part 710; and multiple insulation covers 800 which are disposed in at least one of a first outer area 731, which is one outer area of one of each pair of tab parts 720 within both end surfaces of the body part 710, a second outer area 732, which is the other outer area, and an intermediate area 733, which is an area between each pair of tab parts 720, and cover both end surfaces of the body part 710.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to an electric storage element having an electrode body and a method for manufacturing the same.

2. Description of the Related Art Conventionally, an electric storage element is known in which an electrode body formed by winding an electrode plate is housed in a rectangular container (see, for example, Patent Document 1). A pair of tab portions for the positive electrode and the negative electrode protrude from one end face of the electrode body, and these tab portions are joined to the current collectors (the positive electrode lead member and the negative electrode lead member) arranged in the container. ing.

JP 2010-73580 A

In recent years, it has also been studied to protrude a pair of tab portions from both end surfaces of the wound electrode body. However, in an electrode body in which a pair of tab portions protrudes from each of both end surfaces, even if each tab portion and a current collector are welded together, the open portions at the ends of the electrode body are difficult to be closed, and metal powder, etc. contamination (contamination) may enter the electrode body. As a result, there is a possibility that the reliability of the electric storage element is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric storage device capable of improving reliability and a method of manufacturing the same.

To achieve the above object, a power storage device according to one aspect of the present invention is a power storage device including an electrode body around which a plurality of electrode plates are wound, wherein the electrode body includes a main body and windings on the main body. A plurality of tab portions protruding in pairs from both end faces in the rotation axis direction, a first outer region that is one outer region of each pair of tab portions, and the other outer region in both end faces of the body portion and a plurality of insulating covers disposed in at least one of the second outer region and the intermediate region between each pair of tab portions to cover both end surfaces of the body portion.

According to this, since at least one of the first outer region, the second outer region and the intermediate region of each end surface of the main body of the electrode body is covered with the insulating cover, the intrusion of contamination is prevented by the insulating cover. can be blocked by As a result, short circuits or OCV (open circuit voltage) defects caused by contamination can be suppressed. Therefore, it is possible to provide an electric storage device with improved reliability.

A positive electrode tab portion and a negative electrode tab portion may be provided as a pair of tab portions on each of both end surfaces of the main body portion, and the insulating cover may be arranged in the vicinity of the negative electrode tab portion.

Here, the negative electrode plate constituting the negative electrode tab portion is generally made of copper or a copper alloy. Copper or copper alloys are more susceptible to short circuits than aluminum or aluminum alloys used in positive plates. Therefore, by arranging the insulating cover near the negative electrode tab portion, the insulating cover can block contamination originating from the negative electrode tab portion more reliably, and the reliability of the electric storage element can be further improved.

A positive electrode tab portion and a negative electrode tab portion are provided as a pair of tab portions on each of both end surfaces of the main body portion, and the insulating cover is arranged in a region below the negative electrode tab portion when the electric storage element is in use. Yes, you can.

As described above, copper or copper alloys are more susceptible to short circuits than aluminum or aluminum alloys used in positive plates. For this reason, if an insulating cover is placed in the region below the negative electrode tab portion when the storage element is in use, contamination caused by the negative electrode tab portion can be more reliably blocked by the insulating cover, and the storage element can be more reliable. You can increase your sexuality.

Of the two end faces of the main body, the positive electrode tab portion and negative electrode tab portion provided on one end face and the positive electrode tab portion and negative electrode tab portion provided on the other end face may be reversed.

The inventors of the present application have found that the resistance of the electrode body during charge and discharge is higher when the positive electrode tab portion and the negative electrode tab portion are reversed in arrangement between one end surface and the other end surface of the main body portion of the electrode body compared to the case where the positive electrode tab portion and the negative electrode tab portion are not reversed. was found to be reduced. That is, in the main body of the electrode body, if the positive electrode tab portion and the negative electrode tab portion provided on one end surface and the positive electrode tab portion and the negative electrode tab portion provided on the other end surface are reversed and arranged, the electrode body during charging and discharging resistance can be reduced. This is suitable for an electrode body elongated in the direction of the winding axis, which tends to have high resistance.

The insulating cover may be arranged in all of the first outer region, the second outer region and the intermediate region within both end surfaces of the main body.

According to this, since the insulating cover is arranged in all of the first outer region, the second outer region, and the intermediate region, it is possible to reduce the open portions on both end faces of the electrode body as much as possible. As a result, it is possible to more reliably prevent contamination from entering the electrode body. Therefore, the reliability of the electric storage element can be further improved.

A method for manufacturing a power storage element according to an aspect of the present invention is the above-described method for manufacturing a power storage element, wherein the conductive member is welded to the plurality of tab portions while both end surfaces of the main body portion are covered with a plurality of insulating covers. .

According to this, since the conductive member is welded to the plurality of tab portions in a state in which both end surfaces of the main body portion of the electrode body are covered with the plurality of insulating covers, contamination generated during welding does not enter the electrode body. can be blocked with an insulating cover. Thereby, the reliability of the electric storage element can be further improved.

ADVANTAGE OF THE INVENTION According to this invention, the reliability of an electrical storage element can be improved.

1 is a perspective view showing an appearance of a power storage device according to an embodiment; FIG. 1 is an exploded perspective view showing each component by disassembling a power storage device according to an embodiment; FIG. 1 is a perspective view showing the configuration of an electrode body according to an embodiment; FIG. FIG. 5 is a schematic diagram showing an electrode assembly according to Modification 1 of the embodiment; FIG. 10 is a schematic diagram showing an electrode assembly according to Modification 2 of the embodiment;

Hereinafter, an electric storage element according to an embodiment of the present invention (including modifications thereof) will be described with reference to the drawings. It should be noted that the embodiments described below are all comprehensive or specific examples. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, manufacturing processes, order of manufacturing processes, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each figure, the same reference numerals are given to the same or similar components.

In the following description and drawings, the direction along the winding axis of the electrode body, the extending direction of the electrode body, or the facing direction of the short side of the container is defined as the X-axis direction. The direction facing the long side of the container or the thickness direction of the container is defined as the Y-axis direction. The direction in which the bottom surface of the container body and the top surface of the lid of the container are aligned, or the vertical direction is defined as the Z-axis direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that cross each other (perpendicularly in this embodiment). Depending on the mode of use, the Z-axis direction may not be the vertical direction. A case where the axial direction and the Y-axis direction are parallel to the horizontal direction and the Z-axis direction is the vertical direction will be described as an example.

In the following description, for example, the positive direction of the X-axis indicates the arrow direction of the X-axis, and the negative direction of the X-axis indicates the direction opposite to the positive direction of the X-axis. The same applies to the Y-axis direction and the Z-axis direction. Furthermore, expressions indicating relative directions or orientations such as parallel and orthogonal include cases where they are not strictly the directions or orientations. For example, two directions are orthogonal, not only means that the two directions are completely orthogonal, but also substantially orthogonal, that is, for example, a difference of about several percent It is also meant to include

(Embodiment)
[1 General Description of Storage Element]
First, with reference to FIGS. 1 and 2, a general description of the storage device 10 according to the present embodiment will be given. FIG. 1 is a perspective view showing the appearance of a power storage device 10 according to this embodiment. FIG. 2 is an exploded perspective view showing each component by disassembling the electric storage device 10 according to the present embodiment.

The electric storage element 10 is a secondary battery (single battery) capable of charging and discharging electricity, and is specifically a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The power storage element 10 can be used as a battery or the like for driving a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, agricultural machinery, a construction machinery, or a railway vehicle for an electric railway, or for starting an engine, for example. Used. Examples of such vehicles include electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and gasoline vehicles. Examples of railway vehicles for the electric railway include electric trains, monorails, linear motor cars, and hybrid trains having both diesel engines and electric motors. Moreover, the electric storage element 10 can also be used as a stationary battery or the like for home use or business use.

Note that 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 power storage device 10 may be a primary battery that can use stored electricity without being charged by the user, instead of a secondary battery. The storage element 10 may be a pouch-type storage element. In the present embodiment, a flat rectangular parallelepiped (square) power storage element 10 is illustrated, but the shape of the power storage element 10 is not limited to a rectangular parallelepiped shape, and may be a polygonal prism shape other than a rectangular parallelepiped shape, an elongated cylinder shape, or a rectangular parallelepiped shape. It may have an elliptical cylindrical shape, a cylindrical shape, or the like.

As shown in FIGS. 1 and 2, the storage element 10 includes a container 100, two pairs of electrode terminals 300, and two pairs of external gaskets 400. As shown in FIGS. Two pairs of internal gaskets 500 , two pairs of current collectors 600 , and an electrode assembly 700 are accommodated inside the container 100 . Specifically, a pair of members (positive electrode side and negative electrode side) are arranged on one end surface of the container 100 in the positive direction of the X axis, and the remaining pair of members (positive electrode side) are arranged on the other end surface of the container 100 in the negative direction of the X axis. side and negative electrode side) are arranged. More specifically, on one end face of the container 100 in the positive X-axis direction, the positive-side members are arranged in the positive Z-axis direction, and the negative-side members are arranged in the negative Z-axis direction. On the other end face of the container 100 in the negative direction of the X-axis, the members on the negative electrode side are arranged in the positive direction of the Z-axis, and the members on the positive electrode side are arranged in the negative direction of the Z-axis. In other words, on one end surface and the other end surface of the container 100, the positive electrode side members and the negative electrode side members are reversed (upside down) when viewed in the X-axis direction.

An electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100, but illustration thereof is omitted. As the electrolytic solution, the type is not particularly limited as long as it does not impair the performance of the electric storage element 10, and various kinds can be selected. In addition to the components described above, a spacer disposed on the side or below the electrode body 700, an insulating film wrapping the electrode body 700 and the like, and the like may be disposed.

The container 100 is a rectangular parallelepiped (rectangular or box-shaped) case elongated in the X-axis direction. In this container 100 , both end faces facing each other in the X-axis direction are short side faces 101 , and both end faces facing each other in the Y-axis direction are each long side faces 102 . The pair of short side surfaces 101 are one end surface and the other end surface in the X-axis direction on which the above-described positive electrode side members and negative electrode side members are provided. In the container 100 , of the opposite end surfaces in the Z-axis direction, the end surface in the positive Z-axis direction is the top surface 103 , and the end surface in the negative Z-axis direction is the bottom surface 104 .

The container 100 has a container main body 110 and a lid 120, and the container main body 110 and the lid 120 are assembled to form a rectangular parallelepiped shape. The container body 110 defines a pair of long sides 102 and a bottom surface 104 . The lid 120 has a pair of short side surfaces 101 and a top surface 103 .

Specifically, the container body 110 is a substantially U-shaped sheet metal with an open top when viewed in the X-axis direction. The container body 110 has flat rectangular long side walls forming a pair of long side surfaces 102 at both ends in the Y-axis direction, and flat rectangular rectangular bottom surfaces 104 at the ends in the negative Z-axis direction. It has a shaped bottom wall.

The cover 120 is a substantially U-shaped sheet metal with an open bottom when viewed in the Y-axis direction. The lid body 120 has flat and rectangular short side walls forming a pair of short side surfaces 101 at both ends in the X-axis direction, and a flat plate-like and rectangular top surface 103 at the end in the positive Z-axis direction. It has a rectangular ceiling wall.

With such a configuration, the container 100 has a structure in which the inside is hermetically sealed by joining the container body 110 and the lid 120 by welding or the like after the electrode body 700 and the like are housed inside the container body 110 . ing. The material of container 100 (container main body 110 and lid 120) is not particularly limited, but weldable metals such as stainless steel, aluminum, aluminum alloy, iron, and plated steel plate are preferable.

Although illustration is omitted here, the lid 120 is formed with a liquid injection part and a gas discharge valve. The gas discharge valve is a safety valve that releases the pressure when the pressure inside the container 100 rises excessively. The injection part is a part for injecting an electrolytic solution into the inside of the container 100 when the electric storage element 10 is manufactured.

The electrode terminal 300 is a terminal member (a positive electrode terminal 310 and a negative electrode terminal 320) electrically connected to the electrode body 700 via the current collector 600. As shown in FIG. That is, the electrode terminal 300 leads the electricity stored in the electrode body 700 to the external space of the storage element 10 and introduces the electricity into the internal space of the storage element 10 to store the electricity in the electrode body 700 . is a metal member. Although the material of the electrode terminal 300 is not particularly limited, for example, the electrode terminal 300 (the positive terminal 310 and the negative terminal 320) is made of a conductive material such as aluminum, aluminum alloy, copper, or copper alloy. The electrode terminal 300 is connected (joined) to the current collector 600 and attached to the lid 120 by caulking, welding, or the like. In the present embodiment, the electrode terminal 300 is provided with a shaft portion 330, and the shaft portion 330 is crimped while penetrating the outer gasket 400, the inner gasket 500, and the current collector 600, whereby the current collector is 600 is connected (joined).

The current collectors 600 are arranged in pairs on both sides of the electrode assembly 700 in the X-axis direction, and are connected (joined) to the electrode assembly 700 and the electrode terminals 300 to electrically connect the electrode assembly 700 and the electrode terminals 300. They are conductive current collectors (positive electrode current collector 610 and negative electrode current collector 620). Specifically, the current collector 600 includes a first connection portion 630 that is connected (joined) to a tab portion 720 of the electrode body 700 described later by welding or crimping, and as described above, the electrode terminal 300 is crimped. Alternatively, it integrally has a second connection portion 640 that is connected (joined) by welding or the like and fixed to the lid body 120 . The first connection portion 630 and the second connection portion 640 are flat plate-like portions, and are formed by bending a single sheet metal. The material of the current collector 600 is not particularly limited. 620 is formed of a conductive member such as copper or copper alloy, like the negative electrode base material 751 of the electrode body 700 described later.

The external gasket 400 is arranged between the lid 120 of the container 100 and the electrode terminal 300 , and is a plate-shaped and rectangular insulating seal that insulates and seals between the lid 120 and the electrode terminal 300 . It is a stop member. The internal gasket 500 is a plate-shaped rectangular insulating seal disposed between the lid 120 and the current collector 600 to insulate and seal between the lid 120 and the current collector 600 . It is a member. The outer gasket 400 and the inner gasket 500 are made of, for example, 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-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or It is formed of a resin or the like having electrical insulation such as a composite material thereof.

The electrode body 700 is a storage element (power generation element) formed by winding an electrode plate and capable of storing electricity. The electrode body 700 has an elongated shape extending in the X-axis direction, and has an oval shape when viewed from the X-axis direction. The electrode body 700 has a shape extending in the X-axis direction with a length of, for example, 300 mm or more, specifically about 500 mm to 1500 mm. Therefore, the electrode body 700 is longer in the X-axis direction than in the Z-axis direction. The electrode assembly 700 has a body portion 710 and a plurality of tab portions 720 protruding from the body portion 710 , and the tab portions 720 are connected (joined) to the current collector 600 as described above. The plurality of tab portions 720 protrude in pairs from each of both end surfaces of the body portion 710 in the X-axis direction. For example, on one end face of the body portion 710 in the positive direction of the X axis, a positive electrode tab portion 721 is provided at the end in the positive direction of the Z axis, and a negative electrode tab portion 722 is provided at the end in the negative direction of the Z axis. there is On the other hand, on the other end surface of the body portion 710 in the negative direction of the X axis, a negative electrode tab portion 722 is provided at the end in the positive direction of the Z axis, and a positive electrode tab portion 721 is provided at the end in the negative direction of the Z axis. there is That is, on one end surface and the other end surface of the main body portion 710, the positive electrode tab portion 721 and the negative electrode tab portion 722 are reversed (upside down) when viewed in the X-axis direction. The configuration of such electrode assembly 700 will be described in detail below.

[2 Description of Configuration of Electrode Body 700]
FIG. 3 is a perspective view showing the configuration of the electrode assembly 700 according to this embodiment. Specifically, FIG. 3 shows the configuration of the electrode assembly 700 in which the electrode plates are partially unfolded.

As shown in FIG. 3 , the electrode body 700 has a positive plate 740 , a negative plate 750 , and separators 761 and 762 .

The positive electrode plate 740 is an electrode plate (electrode plate) in which a positive electrode active material layer 742 is formed on the surface of a positive electrode base material 741, which is a long strip-shaped metal foil made of aluminum, an aluminum alloy, or the like. The negative electrode plate 750 is an electrode plate (electrode plate) in which a negative electrode active material layer 752 is formed on the surface of a negative electrode base material 751 which is a long belt-shaped metal foil made of copper, copper alloy, or the like. As the positive electrode base material 741 and the negative electrode base material 751, nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, Al—Cd alloy, etc., which are stable against oxidation-reduction reactions during charging and discharging. As long as it is a material, a known material can be used as appropriate. The positive electrode active material used for the positive electrode active material layer 742 and the negative electrode active material used for the negative electrode active material layer 752 are appropriately known materials as long as they are positive electrode active materials and negative electrode active materials capable of intercalating and deintercalating lithium ions. can be used.

For example, as the positive electrode active material, polyanion compounds such as LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, Spinel-type lithium manganese oxides such as LiMn ₂ O ₄ and LiMn _1.5 Ni _0.5 O ₄ , LiMO ₂ (M is one or more transition metals selected from Fe, Ni, Mn, Co, etc. element) and the like can be used. Examples of negative electrode active materials include lithium metal, lithium alloys (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and lithium metal-containing alloys such as Wood's alloys). , alloys that can absorb and release lithium, carbon materials (e.g. graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), silicon oxides, metal oxides, lithium metal oxides ( Li ₄ Ti ₅ O ₁₂ , etc.), polyphosphate compounds, or compounds of transition metals and group 14 to group 16 elements, such as Co ₃ O ₄ and Fe ₂ P, which are generally called conversion negative electrodes. .

The separators 761 and 762 are microporous sheets made of resin. As materials for the separators 761 and 762, known materials can be appropriately used as long as the performance of the electric storage element 10 is not impaired. For example, as the separators 761 and 762, a woven fabric, a non-woven fabric, a synthetic resin microporous film made of a polyolefin resin such as polyethylene, etc., which is insoluble in an organic solvent, or the like can be used.

The electrode assembly 700 is formed by alternately stacking and winding positive electrode plates 740 and negative electrode plates 750 and separators 761 and 762 . That is, the electrode body 700 is formed by laminating the negative electrode plate 750, the separator 761, the positive electrode plate 740, and the separator 762 in this order and winding them. In the present embodiment, the electrode body 700 is a wound (so-called vertically wound) electrode formed by winding a positive electrode plate 740, a negative electrode plate 750, and the like around a winding axis L extending in the X-axis direction. is the body. The winding axis L is a virtual axis that serves as a central axis when the positive electrode plate 740, the negative electrode plate 750, and the like are wound. They are parallel straight lines.

A plurality of protruding pieces 743 protruding outward are arranged in a zigzag pattern in a plan view of the positive electrode plate 740 at both edges of the positive electrode plate 740 in the winding axis direction. Similarly, a plurality of protruding pieces 753 protruding outward are arranged in a zigzag pattern when the negative electrode plate 750 is viewed from above, at both edges of the negative electrode plate 750 in the direction of the winding axis. In the stacked state, the protruding pieces 743 of the positive electrode plate 740 and the protruding pieces 753 of the negative electrode plate 750 are alternately and repeatedly arranged in the longitudinal direction of the positive electrode plate 740 and the negative electrode plate 750, respectively. Each protruding piece 743 and 753 is a portion (active material layer non-formed portion) where the active material containing the active material is not formed and the base layer is exposed.

When the positive electrode plate 740, the negative electrode plate 750, and the separators 761 and 762 are wound, the protruding pieces 743 of the positive electrode plate 740 are overlapped with each other on the one end surface and the other end surface of the main body portion 710, respectively, and the negative electrode plate Each projecting piece 753 of 750 overlaps. A positive electrode tab portion 721 is a portion where the projecting pieces 743 of the positive electrode plate 740 are overlapped with each other. That is, the positive electrode tab portion 721 is formed by stacking a plurality of pieces (protruding pieces 743) of the electrode plates (the positive electrode plate 740) having the same polarity among the plurality of electrode plates (the positive electrode plate 740 and the negative electrode plate 750). It is a part.

Similarly, the portion where the projecting pieces 753 of the negative electrode plate 750 are overlapped with each other is the negative electrode tab portion 722 . That is, the negative electrode tab portion 722 is formed by stacking a plurality of pieces (protruding pieces 753) of the electrode plates (the negative electrode plate 750) having the same polarity among the plurality of electrode plates (the positive electrode plate 740 and the negative electrode plate 750). It is a part.

That is, the electrode body 700 includes a main body portion 710 constituting the main body of the electrode body 700, and a plurality of tab portions 720 (a positive electrode tab portion 721 and a negative electrode tab portion) projecting from each of both end surfaces of the main body portion 710 in the X-axis direction. 722) and .

The body portion 710 is formed by winding a portion of the positive electrode plate 740 and the negative electrode plate 750 on which the positive electrode active material layer 742 and the negative electrode active material layer 752 are formed (coated) and the separators 761 and 762 . This is a cylindrical portion (active material layer forming portion). Thereby, the body portion 710 has a pair of curved portions 711 on both sides in the Z-axis direction, and has a flat portion 712 that is flat as a whole between the pair of curved portions 711 . It can also be said that the pair of curved portions 711 are arranged at positions sandwiching the flat portion 712 in the Z-axis direction.

The curved portion 711 is a curved portion extending in the X-axis direction, curved in a semicircular arc shape so as to protrude in the Z-axis direction when viewed from the X-axis direction. , and the top wall of the lid 120 . That is, the pair of curved portions 711 are portions curved so as to protrude toward both sides in the Z-axis direction toward the bottom wall portion of the container body 110 and the top wall portion of the lid body 120 when viewed from the X-axis direction. The flat portion 712 is a rectangular and flat portion that connects the ends of the pair of curved portions 711 and spreads parallel to the XZ plane facing the Y-axis direction. placed facing the part. 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 or the like, and may be curved in any way. The flat portion 712 is not limited to having a flat outer surface facing the Y-axis direction, and the outer surface may be slightly concave or slightly bulging.

Each tab portion 720 is spaced apart from the curved portion 711 and protrudes from a position continuous with the flat portion 712 on both end surfaces of the main body portion 710 . Here, in both end surfaces of the main body portion 710, one (Z-axis positive direction) outer region of each pair of tab portions 720 is defined as a first outer region 731, and the other (Z-axis negative direction) outer region is defined as a first outer region 731. is called a second outer region 732 . A region between each pair of tab portions 720 is referred to as an intermediate region 733 . As shown in FIG. 2, insulating covers 800 are arranged in the first outer region 731, the second outer region 732, and the intermediate region 733, respectively. It is Specifically, the insulating cover 800 arranged in the first outer region 731 on one end face of the main body portion 710 in the plus direction of the X-axis is arranged near and above the positive electrode tab portion 721 provided on the one end face. there is The insulating cover 800 arranged in the second outer region 732 of the one end face of the main body part 710 is arranged near and below the negative electrode tab part 722 provided on the one end face. The insulating cover 800 arranged in the intermediate region 733 of one end face of the main body part 710 is arranged in the vicinity of the lower part of the positive electrode tab part 721 and in the upper part of the negative electrode tab part 722 provided on the one end face.

Similarly, the insulating cover 800 arranged in the first outer region 731 of the other end surface of the main body portion 710 in the negative direction of the X axis is arranged near and above the negative electrode tab portion 722 provided on the other end surface. The insulating cover 800 arranged in the second outer region 732 of the other end face of the main body part 710 is arranged near and below the positive electrode tab part 721 provided on the other end face. The insulating cover 800 arranged in the intermediate region 733 of the other end surface of the main body part 710 is arranged in the vicinity of the lower part of the negative electrode tab part 722 and in the upper part of the positive electrode tab part 721 provided on the other end surface.

Each insulating cover 800 is an adhesive tape having a rectangular sheet shape in a plan view and formed of a resin or the like having insulating properties similar to that of the outer gasket 400, and an adhesive layer is laminated on one surface thereof. Both ends of each insulating cover 800 are attached to a pair of outer surfaces of the flat portions 712 of the body portion 710 , and an intermediate portion covers the end face of the body portion 710 . Since the insulating cover 800 is an adhesive tape, the insulating cover 800 can be easily fixed to the electrode assembly 700 simply by sticking it. The insulating cover 800 may be, for example, a clip-shaped insulating member that does not have an adhesive layer and engages the electrode body 700 by its own elasticity.

The timing at which the insulating cover 800 is attached to the electrode body 700 in manufacturing the storage element 10 is before the current collector 600 is welded to the plurality of tab portions 720 . Contamination is most likely to occur when each tab portion 720 and the current collector 600 are welded by ultrasonic welding. In order to prevent contamination generated by ultrasonic welding from entering, each insulating cover 800 is preferably attached to the electrode body 700 to cover both end surfaces of the main body 710 before the welding.

In order to reliably suppress a short circuit between the positive electrode tab portion 721 and the negative electrode tab portion 722 due to positional misalignment between the positive electrode tab portion 721 and the negative electrode tab portion 722, the width of the intermediate region 733 (Z-axis direction length) is preferably 20 mm or more. From the viewpoint of ensuring the strength of the tab portion 720 and ensuring the welding width, the width (the length in the Z-axis direction) of the tab portion 720 should be 10 mm or more, and more preferably 20 mm or more.

[3 Explanation of effects]
As described above, power storage device 10 according to the embodiment of the present invention includes electrode body 700 in which a plurality of electrode plates (positive electrode plate 740 and negative electrode plate 750) are wound. The electrode body 700 includes a body portion 710 , a plurality of tab portions 720 projecting from each of both end surfaces of the body portion 710 in the winding axis direction (X-axis direction), Of the first outer region 731 that is one outer region of the tab portion 720, the second outer region 732 that is the other outer region, and the intermediate region 733 that is the region between each pair of tab portions 720 , and a plurality of insulating covers 800 arranged in at least one region and covering both end surfaces of the body portion 710 .

According to this, at least one of the first outer region 731, the second outer region 732, and the intermediate region 733 of each end surface of the main body 710 of the electrode body 700 is covered with the insulating cover 800. Intrusion of contamination can be blocked by the insulating cover 800 . As a result, short circuits or OCV (open circuit voltage) defects caused by contamination can be suppressed. Therefore, it is possible to provide the electric storage device 10 capable of improving reliability.

In particular, in the present embodiment, since the insulating cover 800 is arranged in all of the first outer region 731, the second outer region 732, and the intermediate region 733, the openings on both end surfaces of the electrode body 700 are reduced as much as possible. can do. Therefore, it is possible to more reliably prevent contamination from entering the electrode body 700, and the reliability of the electric storage element 10 can be further enhanced.

A positive electrode tab portion 721 and a negative electrode tab portion 722 are provided as a pair of tab portions 720 on each of both end surfaces of the main body portion 710 , and the insulating cover 800 is arranged near the negative electrode tab portion 722 . .

Here, the negative electrode plate 750 forming the negative electrode tab portion 722 is mainly made of copper or a copper alloy. Copper or copper alloys are more susceptible to short circuits than aluminum or aluminum alloys used for the positive electrode plate 740 . Therefore, if the insulating cover 800 is arranged in the vicinity of the negative electrode tab portion 722, the contamination caused by the negative electrode tab portion 722 can be blocked by the insulating cover 800 more reliably, and the reliability of the electric storage element 10 can be further improved. can be done.

In particular, in the present embodiment, the insulating cover 800 is arranged in the area below the negative electrode tab portion 722 when the power storage element 10 is in use. 800 can be blocked.

Here, from the viewpoint of suppressing entry of contamination, the gap between the negative electrode tab portion 722 and the insulating cover 800 adjacent to the negative electrode tab portion 722 should be smaller than the width of the negative electrode tab portion 722 (the length in the Z-axis direction). It is preferable that the width is half or less of the width of the negative electrode tab portion 722 . More preferably, the insulating cover 800 is in contact with the negative electrode tab portion 722 . This also applies to the positive electrode tab portion 721 .

In addition, the positive electrode tab portion 721 and the negative electrode tab portion 722 provided on one end face of the main body portion 710 and the positive electrode tab portion 721 and the negative electrode tab portion 722 provided on the other end face are reversed.

The inventors of the present application have found that when the positive electrode tab portion 721 and the negative electrode tab portion 722 are inverted between one end surface and the other end surface of the main body portion 710 of the electrode body 700, the charge/discharge time is greater than when they are not inverted. It has been found that the resistance of the electrode assembly 700 is reduced. That is, in the main body portion 710 of the electrode assembly 700, if the positive electrode tab portion 721 and the negative electrode tab portion 722 provided on one end surface and the positive electrode tab portion 721 and the negative electrode tab portion 722 provided on the other end surface are arranged reversely, It is possible to reduce the resistance of the electrode body 700 during charging and discharging. This is suitable for the electrode body 700 elongated in the direction of the winding axis, which tends to have high resistance.

Further, according to the method for manufacturing electric storage element 10 according to the embodiment of the present invention, current collector 600 is attached to tab portions 720 while both end surfaces of main body portion 710 are covered with insulating covers 800 . Weld the (conductive member).

According to this, since the current collector 600 is welded to the plurality of tab portions 720 in a state in which both end surfaces of the main body portion 710 of the electrode body 700 are covered with the plurality of insulating covers 800, contamination generated during welding is reduced. Intrusion into the electrode body 700 can be blocked by the insulating cover 800 . Thereby, the reliability of the electric storage element 10 can be further improved.

[4 Description of modified example]
Modifications of the above embodiment will be described below. In the following description, parts that are the same as those of the above-described embodiment or other modifications may be denoted by the same reference numerals, and descriptions thereof may be omitted.

(Modification 1)
Next, Modification 1 of the above embodiment will be described. FIG. 4 is a schematic diagram showing an electrode body 700a according to Modification 1 of the embodiment. In FIG. 4, the negative electrode tab portion 722 is indicated by dot hatching.

In the above embodiment, the case where the insulating cover 800 is arranged for all of the first outer region 731 , the second outer region 732 and the intermediate region 733 of the electrode body 700 is illustrated. However, if the insulating cover is arranged in at least one region of the first outer region, the second outer region, and the intermediate region on each of both end surfaces of the electrode body, a certain effect of suppressing contamination entry can be obtained. is possible. For example, FIG. 4 shows a case where the insulating cover 800a is attached only to the lower vicinity of the negative electrode tab portion 722 on both end surfaces of the main body portion 710a. In this case, contamination falling from the negative electrode tab portion 722 can be blocked by the insulating cover 800a. In other words, it is possible to effectively obtain the effect of suppressing entry of contaminants while reducing the number of insulating covers 800a to be installed.

(Modification 2)
Next, Modification 2 of the above embodiment will be described. FIG. 5 is a perspective view showing an electrode body 700b according to Modification 2 of the embodiment. Specifically, FIG. 5 is a diagram corresponding to FIG.

As shown in FIG. 5, in the electrode body 700b according to this modification, the positive electrode tab portion 721b and the negative electrode tab portion 722b on both end surfaces of the body portion 710b are not reversed. Specifically, a negative electrode tab portion 722b is provided at an upper end portion of one end surface and the other end surface of the main body portion 710b, and a positive electrode tab portion 721b is provided at a lower end portion thereof. In this case also, the insulating covers 800b are arranged in the first outer region 731, the second outer region 732, and the intermediate region 733 on both end surfaces of the main body portion 710b. are covered on both end faces.

(Other modifications)
Although the storage elements according to the embodiments of the present invention (including modifications thereof; the same applies hereinafter) have been described above, the present invention is not limited to the above embodiments. The embodiments disclosed this time are illustrative in all respects, and the scope of the present invention includes all modifications within the meaning and range of equivalents to the scope of the claims.

For example, in the above-described embodiment, the current collector 600 is exemplified as the conductive member welded to the tab portion 720, but it is also possible to exemplify the electrode terminal as the conductive member welded to the tab portion.

Moreover, in the above-described embodiment, the case where the conductive members are welded to the plurality of tab portions 720 in a state where both end surfaces of the main body portion 710 are covered with the plurality of insulating covers 800 is illustrated. However, the conductive members may be welded to the plurality of tab portions 720 and then both end surfaces of the body portion 710 may be covered with the plurality of insulating covers 800 .

Forms constructed by arbitrarily combining the constituent elements included in the above embodiments and modifications thereof are also included within the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be applied to storage elements such as lithium ion secondary batteries.

10 Storage element 100 Container 101 Short side 102 Long side 103 Top surface 104 Bottom surface 110 Container body 120 Lid 300 Electrode terminal 310 Positive electrode terminal 320 Negative electrode terminal 330 Shaft 400 External gasket 500 Internal gasket 600 Current collector (conductive member)
610 positive electrode current collector 620 negative electrode current collector 630 first connecting portion 640 second connecting portion 700, 700a, 700b electrode bodies 710, 710a, 710b body portion 711 curved portion 712 flat portion 720 tab portions 721, 721b positive electrode tab portion 722 , 722b negative electrode tab portion 731 first outer region 732 second outer region 733 intermediate region 740 positive electrode plate 741 positive electrode substrate 742 positive electrode active material layers 743, 753 projecting piece 750 negative electrode plate 751 negative electrode substrate 752 negative electrode active material layer 761 , 762 separators 800, 800a, 800b insulating covers

Claims (6)

A power storage element comprising an electrode body in which a plurality of electrode plates are wound,
The electrode body is
a main body;
a plurality of tab portions protruding in pairs from each of both end surfaces of the main body portion in the winding axis direction;
In the both end surfaces of the main body, a first outer region that is one outer region of each pair of tab portions, a second outer region that is the other outer region of each pair of tab portions, and and a plurality of insulating covers arranged in at least one region of an intermediate region, which is a region between the two, and covering the both end surfaces of the main body. A positive electrode tab portion and a negative electrode tab portion are provided as a pair of tab portions on each of both end surfaces of the main body portion,
The electric storage element according to claim 1, wherein the insulating cover is arranged in the vicinity of the negative electrode tab portion. A positive electrode tab portion and a negative electrode tab portion are provided as a pair of tab portions on each of both end surfaces of the main body portion,
The electric storage device according to claim 1, wherein the insulating cover is arranged in a region below the negative electrode tab portion when the electric storage device is in use. 2. The positive electrode tab portion and the negative electrode tab portion provided on one end surface of the main body portion and the positive electrode tab portion and the negative electrode tab portion provided on the other end surface of the main body portion are arranged reversely. 4. Or the electric storage element of 3. 5. The insulating cover according to any one of claims 1 to 4, wherein the insulating cover is arranged in all of the first outer region, the second outer region, and the intermediate region in the both end surfaces of the main body. The storage element described. In the method for manufacturing the electric storage element according to any one of claims 1 to 5,
The method of manufacturing an electric storage element, wherein the conductive member is welded to the plurality of tab portions in a state in which the both end surfaces of the main body portion are covered with the plurality of insulating covers.

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