JP7259261B2 - Storage element - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric storage element that includes an electrode body, spacers arranged on the sides of the electrode body, and a container that accommodates the electrode body and the spacer.

2. Description of the Related Art Conventionally, an electric storage element is widely known that includes an electrode body, spacers arranged on the sides of the electrode body, and a container that accommodates the electrode body and the spacer. For example, in Patent Document 1, by providing a buffer sheet (spacer) in contact with the electrode assembly (electrode body) and the battery case in the battery case (container), the buffer sheet cushions the electrode assembly. , a secondary battery (capacity storage element) that prevents severe impact from being transmitted to the electrode assembly is disclosed.

JP 2011-82162 A

However, in the above-described conventional electric storage device, there is a possibility that the electrode assembly may be damaged. In other words, the inventors of the present application have found that the electric storage element disclosed in Patent Document 1 includes a wound electrode body, but the wound electrode body has a curved surface on the outer surface, so that the electrode body is It has been found that when expanded, stress concentrates on the edge of the curved surface (the boundary between the curved surface and the flat surface), and the edge of the curved surface is easily damaged. However, just placing a buffer sheet between the electrode body and the container as in the electric storage device disclosed in Patent Document 1 cannot prevent the end of the curved surface from being damaged.

The present invention has been made with a new focus on the above problem, and an object of the present invention is to provide an electric storage element capable of suppressing damage to an electrode assembly.

To achieve the above object, a power storage device according to an aspect of the present invention includes an electrode assembly, a spacer arranged on the first direction side of the electrode assembly, and a container accommodating the electrode assembly and the spacer. a first wall portion arranged on the first direction side of the spacer; and a second direction adjacent to the first wall portion and intersecting the first direction. and a second wall portion and a third wall portion facing each other at a position where the electrode body protrudes in the first direction when viewed from a third direction that intersects the first direction and the second direction. The spacer is disposed in contact with the first wall portion and at least one of the second wall portion and the third wall portion, and extends in the third direction. When viewed from above, it is arranged in continuous contact with the curved surface from a position facing the second wall portion to a position facing the third wall portion of the curved surface.

According to this, in the electric storage element, the spacer is disposed in contact with the first wall portion of the container and at least one of the second wall portion and the third wall portion, and is arranged to contact the electrode when viewed from the third direction. It is arranged in contact with the curved surface of the body from a position facing the second wall portion to a position facing the third wall portion. In this way, since the curved surface of the electrode body is in continuous contact with the spacer from the position facing the second wall portion to the position facing the third wall portion, when the electrode body expands In addition, the stress can be dispersed by pressing the curved surface with a relatively wide surface of the spacer. As a result, it is possible to prevent damage to the ends of the curved surface of the electrode assembly due to concentration of stress on the ends of the curved surface of the electrode assembly, thereby suppressing damage to the electrode assembly.

Further, the spacer may be arranged in contact with the curved surface continuously from one end to the other end of the portion facing the curved surface in the third direction.

According to this, the spacer is arranged in contact with the curved surface from one end to the other end of the portion facing the curved surface of the electrode body in the third direction. In this way, since the spacer is in continuous contact with the curved surface from one end to the other end of the portion facing the curved surface, the curved surface is pressed by the wider surface of the spacer, Stress can be distributed. As a result, it is possible to further suppress damage to the ends of the curved surface due to concentration of stress on the ends of the curved surface of the electrode body, so that it is possible to further suppress damage to the electrode body.

Moreover, the length of the electrode body in the first direction may be longer than the length in the third direction.

According to this, the electrode body is formed such that the length in the first direction (projection direction of the curved surface) is longer than the length in the third direction. Thus, in the electrode body, since the length in the first direction is long, a large stress is generated in the first direction. Therefore, the effect of dispersing the stress in the first direction by the spacer is large. Thereby, even if the electrode body expands and a large stress is generated in the first direction, the stress can be dispersed by the spacer, so that damage to the electrode body can be suppressed.

Further, the electrode body may have a main body portion having the curved surface, and a tab portion arranged to protrude from a part of the main body portion in the third direction and connected to a current collector. .

According to this, the electrode body has a configuration in which a curved surface is formed on the main body portion, and the current collector is connected to the tab portion protruding from the main body portion. Here, for example, in the case of an electrode body configured such that the end portion of the curved surface of the electrode body serves as the active material layer non-formed portion and is connected to the current collector, the curved surface is likely to be dented and deformed. It is difficult to bring the spacer into close contact with the curved surface. Therefore, by forming a curved surface on the body portion of the electrode body and connecting the current collector to the tab portion of the electrode body, even if the current collector is connected to the electrode body, the curved surface is deformed. and the curved surface is easily brought into close contact with the spacer. As a result, the curved surface can be easily pressed by the spacer, so stress concentration on the edge of the curved surface can be suppressed, and damage to the edge can be suppressed, thereby suppressing damage to the electrode assembly. can do.

Further, the spacer may be arranged in continuous contact with an area of 50% or more and 90% or less of the curved surface when viewed from the third direction.

According to this, the spacer is arranged in continuous contact with an area of 50% or more and 90% or less of the curved surface of the electrode body when viewed from the third direction. By arranging the spacer in contact with an area of 50% or more of the curved surface of the electrode body in this manner, the curved surface can be pressed by the relatively wide surface of the spacer, so that the electrode body expands. can also distribute stress. Moreover, if the contact area of the spacer with the curved surface is made too large, the tip of the spacer may become sharp and damage the electrode body. Form to touch. By these, it can suppress that an electrode body is damaged.

Further, the spacer may have an extending portion extending in a direction opposite to the first direction from a contact portion with the curved surface.

According to this, since the spacer has the extending portion extending in the direction opposite to the first direction (projection direction of the curved surface) from the contact portion with the curved surface of the electrode body, the electrode body Even if the electrode expands, the stress from the electrode body can be received by the extended portion. As a result, the stress from the electrode body can be distributed to the extended portion, so that damage to the electrode body can be suppressed.

Further, the spacer may be formed with an electrolytic solution passageway penetrating in the third direction.

According to this, the electrolyte passage is formed in the spacer, penetrating in the third direction. In other words, when the spacers are placed in contact with the three walls of the container and the curved surface of the electrode body, the electrolyte cannot pass through the spacers, and the electrolyte may not pass through the spacers. The spacer is formed with an electrolyte passageway. Thereby, the liquid permeability of the electrolytic solution can be improved.

Further, the liquid passage may have a plurality of through holes radially extending from the curved surface when viewed from the third direction.

According to this, the passage for the electrolytic solution formed in the spacer has a plurality of through holes radially extending from the curved surface of the electrode body. In other words, if the electrolyte passage is formed in the spacer, the spacer may not be able to sufficiently receive the stress caused by the expansion of the electrode body in the portion of the passage. In particular, since the stress when the electrode body expands radially spreads from the curved surface, forming a through-hole extending in a non-radial direction from the curved surface, such as along the curved surface of the electrode body, as the liquid passage, can reduce the stress. The area that cannot receive enough is enlarged. On the other hand, by forming a plurality of through holes radially extending from the curved surface, the strength against the stress can be increased. For this reason, a plurality of through holes radially extending from the curved surface are formed as the liquid passages. As a result, even if the electrode body expands, the stress can be received by the spacer and dispersed, so that the electrode body can be prevented from being damaged while improving the liquid permeability of the electrolytic solution. .

The present invention can be realized not only as such an electric storage element, but also as a spacer included in the electric storage element.

According to the electric storage element of the present invention, damage to the electrode assembly can be suppressed.

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. 3A and 3B are a perspective view and a cross-sectional view showing the configuration of a spacer according to an embodiment; FIG. FIG. 4 is a perspective view showing a positional relationship among a spacer, an electrode assembly, and a container body of the container according to the embodiment; FIG. 4 is a cross-sectional view showing the positional relationship among the spacer, the electrode assembly, and the container body of the container according to the embodiment; FIG. 4 is a cross-sectional view showing the positional relationship among the spacer, the electrode assembly, and the container body of the container according to the embodiment; 8A and 8B are a perspective view and a cross-sectional view showing a configuration of a spacer according to a modification of the embodiment; FIG.

Hereinafter, an electric storage device according to an embodiment (and a modification thereof) of the present invention 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, components, arrangement positions and connection forms of components, 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 addition, among the constituent elements in the following embodiments, constituent elements that are not described in independent claims representing the highest concept will be described as arbitrary constituent elements. Also, in each drawing, dimensions and the like are not strictly illustrated.

Further, in the following description and drawings, the direction in which a pair of electrode terminals (on the positive electrode side and the negative electrode side) of a storage element are aligned, the direction in which a pair of current collectors are aligned, the direction in which a pair of tab portions of an electrode body are aligned, The direction in which the pair of spacers are arranged or the direction in which the short sides of the container face each other is defined as the X-axis direction. The Y-axis direction is defined as the facing direction of the long sides of the container, the widthwise direction of the short sides of the container, or the thickness direction of the container. The direction in which the electrode terminal, current collector, and electrode body are arranged, the direction in which the container body and lid of the storage element are arranged, the longitudinal direction of the short side of the container, the winding axial direction of the electrode body, the extending direction of the spacer, 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). Although the Z-axis direction may not be the vertical direction depending on the mode of use, the Z-axis direction will be described below for convenience of explanation. Further, in the following description, for example, 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 opposite direction to the positive direction of the X-axis. The same applies to the Y-axis direction and the Z-axis direction. Furthermore, hereinafter, the X-axis direction (or the X-axis minus direction) is also called the first direction, the Y-axis direction is also called the second direction, and the Z-axis direction (or the Z-axis plus direction) is also called the third direction. do.

(Embodiment)
[1 General Description of Electricity Storage Element 10]
First, 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 storage element 10 is a secondary battery capable of charging and discharging electricity, and specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The power storage element 10 can be used, for example, in automobiles such as electric vehicles (EV), hybrid electric vehicles (HEV) or plug-in hybrid electric vehicles (PHEV), motorcycles, watercraft, snowmobiles, agricultural machinery, construction machinery, or trains. , monorails, linear motor cars, and other electric railway vehicles.

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. Also, the storage device 10 may be a primary battery that allows the stored electricity to be used without being charged by the user, instead of a secondary battery. In addition, in the present embodiment, a 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 columnar shape or an oval columnar shape other than a rectangular parallelepiped shape. etc., or a laminate-type electric storage device.

As shown in FIG. 1 , the storage element 10 includes a container 100 , a pair of electrode terminals 200 (positive electrode side and negative electrode side), and a pair of upper gaskets 300 (positive electrode side and negative electrode side). As shown in FIG. 2, inside the container 100, a pair of lower gaskets 400 (positive electrode side and negative electrode side), a pair of current collectors 500 (positive electrode side and negative electrode side), and a buffer sheet 600 are provided. , an electrode body 700 and a pair of spacers 800 (positive electrode side and negative electrode side) are accommodated. Also, an electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100, but is omitted from the drawing. 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 above components, a spacer arranged above the electrode assembly 700, or an insulating film or the like that wraps the electrode assembly 700 or the like may be arranged.

The container 100 is a rectangular parallelepiped (box-shaped) case having a container body 110 with an opening and a lid 120 closing the opening of the container body 110 . With such a configuration, the container 100 has a structure that can hermetically seal the interior by welding the container body 110 and the lid body 120 together after the electrode body 700 and the like are housed inside the container body 110 . ing. Although the materials of the container body 110 and the lid 120 are not particularly limited, they are preferably weldable metals such as stainless steel, aluminum, aluminum alloys, iron, and plated steel plates.

The container main body 110 is a rectangular tubular member that constitutes the main body of the container 100 and has a bottom, and an opening is formed in the positive direction of the Z axis. That is, the container main body 110 has a pair of short side walls 111 and 112 on both sides in the X-axis direction, and a pair of long side walls 113 and 114 on both sides in the Y-axis direction. It has a bottom wall portion 115 at the bottom. The short side walls 111 and 112 are rectangular flat walls forming the short side surfaces of the container 100 , and the long side walls 113 and 114 are rectangular flat wall portions forming the long side surfaces of the container 100 . The bottom wall portion 115 is a rectangular flat wall portion that forms the bottom surface of the container 100 . The short side wall portion 111 or 112 is an example of a first wall portion, and the long side wall portions 113 and 114 are adjacent to the first wall portion and face each other in the Y-axis direction (second direction). It is an example of a second wall portion and a third wall portion.

The lid body 120 is a rectangular plate-like member that constitutes the lid portion of the container 100 , and is arranged to extend in the X-axis direction on the Z-axis plus direction side of the container body 110 . Further, the cover 120 is formed with a liquid injection port 121 which is a circular through hole for injecting the electrolytic solution into the container 100 . A liquid injection plug 130 is arranged to block the 121 . Further, the lid 120 is provided with a gas discharge valve 122 for discharging the gas inside the container 100 when the internal pressure of the container 100 rises.

The electrode body 700 is a power storage element (power generation element) that includes a positive electrode plate, a negative electrode plate, and a separator, and can store electricity. Specifically, the electrode body 700 is formed by winding a positive electrode plate and a negative electrode plate, which are arranged in layers so that a separator is sandwiched between them. Thus, a plurality of tabs of the positive electrode plate are laminated to form a positive electrode side tab portion 720 , and a plurality of negative electrode plate tabs are laminated to form a negative electrode side tab portion 730 . That is, the electrode body 700 has an electrode body body portion 710 and tab portions 720 and 730 that protrude from a part of the electrode body body portion 710 in the positive Z-axis direction (third direction) and extend in the positive Y-axis direction. ing. In this embodiment, the cross-sectional shape of the electrode assembly 700 is illustrated as an elliptical shape, but it may be an elliptical shape or the like. A detailed description of the configuration of this electrode body 700 will be given later.

The electrode terminal 200 is an electrode terminal electrically connected to the electrode body 700 via the current collector 500 . The electrode terminal 200 is connected to the current collector 500 and attached to the lid 120 by caulking or the like. Specifically, the electrode terminal 200 has a shaft portion 201 (rivet portion) extending downward (Z-axis negative direction). Then, the shaft portion 201 is inserted into the through hole 301 of the upper gasket 300, the through hole 123 of the lid 120, the through hole 401 of the lower gasket 400, and the through hole 501 of the current collector 500, and crimped. . Thereby, the electrode terminal 200 is fixed to the lid 120 together with the upper gasket 300 , the lower gasket 400 and the current collector 500 . In addition, the electrode terminal 200 is formed of a conductive member such as a metal such as aluminum, an aluminum alloy, copper, or a copper alloy.

The current collector 500 is a rectangular plate-like member that electrically connects the electrode body 700 and the electrode terminal 200 . Specifically, the current collector 500 on the positive electrode side is connected (joined) to the tab portion 720 on the positive electrode side of the electrode body 700 by welding or the like, and as described above, the electrode terminal 200 on the positive electrode side is crimped or the like. spliced. The same applies to the negative electrode side. The current collector 500 is made of a conductive member such as metal such as aluminum, aluminum alloy, copper or copper alloy. The method of connecting (joining) the current collector 500 and the electrode terminal 200 is not limited to caulking, and welding such as ultrasonic joining, laser welding, or resistance welding, or other than caulking such as screw fastening. Mechanical bonding or the like may also be used. As a method for connecting (bonding) the current collector 500 and the tab portions 720 and 730, any welding such as ultrasonic bonding, laser welding, resistance welding, or the like may be used. A mechanical bond such as a bonding may be used.

The spacers 800 are arranged to extend in the Z-axis direction between both side surfaces of the electrode body 700 in the X-axis direction (first direction) and the inner surface of the container 100 , and adjust the position of the electrode body 700 in the container 100 . It is a pillar-shaped side spacer that regulates. The spacer 800 is made of, for example, polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), polyethylene terephthalate (PET), polyetheretherketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), It is made of resin such as polytetrafluoroethylene (PTFE), polybutylene terephthalate (PBT), polyethersulfone (PES), and composite materials thereof. A detailed description of the configuration of this spacer 800 will be given later.

The upper gasket 300 is a flat insulating sealing member arranged between the lid 120 of the container 100 and the electrode terminal 200 . The lower gasket 400 is a planar insulating sealing member arranged between the lid 120 and the current collector 500 . The upper gasket 300 and the lower gasket 400 are made of insulating material such as PP, PE, PPS, etc., like the spacer 800, for example. The cushioning sheet 600 is made of a highly flexible porous material such as foamed polyethylene, and is a member that functions as a cushioning material that protects the electrode body 700 .

[2 Description of Configuration of Electrode Body 700]
Next, the configuration of electrode assembly 700 will be described in detail. FIG. 3 is a perspective view showing the configuration of the electrode assembly 700 according to this embodiment. Specifically, (a) of FIG. 3 shows a configuration in which the wound state of the electrode body 700 shown in FIG. 2 is partially unfolded, and (b) of FIG. Body 700 is shown enlarged.

As shown in (a) of FIG. 3, the electrode assembly 700 is formed by alternately stacking and winding a positive electrode plate 740, a negative electrode plate 750, and separators 760a and 760b. That is, the electrode body 700 is formed by laminating the positive electrode plate 740, the separator 760a, the negative electrode plate 750, and the separator 760b in this order and winding them.

The positive electrode plate 740 is an electrode plate (electrode plate) in which a positive electrode active material layer is formed on the surface of a positive electrode base material layer, 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 is formed on the surface of a negative electrode base material layer, which is a long belt-shaped metal foil made of copper, a copper alloy, or the like. As the positive electrode active material used for the positive electrode active material layer and the negative electrode active material used for the negative electrode active material layer, any positive electrode active material and negative electrode active material capable of intercalating and deintercalating lithium ions can be appropriately known materials. can be used. The separators 760a and 760b are microporous sheets made of resin. As the material for the separators 760a and 760b, known materials can be used as appropriate as long as the performance of the storage element 10 is not impaired.

Here, the positive electrode plate 740 has a plurality of rectangular tabs 741 projecting outward from one end in the direction of the winding axis. Similarly, the negative electrode plate 750 has a plurality of rectangular tabs 751 protruding outward at one end in the winding axial direction. The plurality of tabs 741 and the plurality of tabs 751 are not formed with an active material layer (are not coated with an active material) and are exposed portions of the substrate layer (active material layer non-formed portion or active material uncoated portion). ). The shape of the tabs 741 and 751 is not particularly limited. It does not have to have a shape. Further, the winding axis 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. is a straight line parallel to

The plurality of tabs 741 and the plurality of tabs 751 are arranged at the end on the same side in the winding axial direction (the end on the positive side of the Z-axis in FIG. 3), and the positive electrode plate 740 and the negative electrode plate 750 are laminated. By doing so, they are laminated at predetermined positions of the electrode body 700 . As a result, as shown in FIG. 3B, the electrode body 700 has a tab portion 720 formed by stacking a plurality of tabs 741 and a tab portion 720 formed by stacking a plurality of tabs 751 . A tab portion 730 is formed. The tab portions 720 and 730 are gathered toward the center in the stacking direction (the Y-axis direction in FIG. 3), for example, and joined to the current collector 500 by welding or the like.

Here, when the tab portions 720 and 730 are joined to the current collector 500, the tab portions 720 and 730 are bent in the positive Y-axis direction as shown in FIG. Specifically, the tab portions 720 and 730 are joined to the current collector 500 in a state of protruding in the positive Z-axis direction from a portion of the electrode main body portion 710, and after joining, are bent in the positive Y-axis direction, It is in a state of being extended in the Y-axis plus direction. Therefore, after the bonding, the tab portions 720 and 730 are laminated in the Z-axis direction with a plurality of tabs 741 and 751 projecting in the positive Z-axis direction from a part of the electrode body main portion 710 and extending in the positive Y-axis direction. It becomes the part where it was done. Note that the tab portions 720 and 730 may be configured so as not to be bent even after being joined to the current collector 500 .

Electrode body main portion 710 is a portion that constitutes the main body of electrode body 700 , specifically, a portion of electrode body 700 other than tab portions 720 and 730 (other than tabs 741 and 751 ). In other words, the electrode body main body 710 has an oblong cylindrical shape formed by winding the portions of the positive electrode plate 740 and the negative electrode plate 750 on which the active material layers are formed (coated with the active material) and the separators 760a and 760b. It is a part (active material layer forming part or active material coating part). Thus, the electrode body main portion 710 has a pair of electrode body curved surfaces 711 and 712 on both sides in the X-axis direction, and a pair of electrode body flat surfaces 713 and 714 on both sides in the Y-axis direction.

The electrode body curved surface 711 is a curved surface extending in the Z-axis direction, curved in a semicircular arc shape so as to protrude in the X-axis negative direction when viewed from the Z-axis direction, and is a container body of the container 100 . The short side wall portion 111 of 110 and the ends of the long side wall portions 113 and 114 on the negative direction side of the X axis are arranged so as to face each other. The electrode body curved surface 712 is a curved surface extending in the Z-axis direction, curved in a semicircular arc shape so as to protrude in the X-axis positive direction when viewed from the Z-axis direction. It is arranged to face the side wall portion 112 and the ends of the long side wall portions 113 and 114 on the positive side of the X axis. The electrode body flat surface 713 is a rectangular flat surface extending parallel to the XZ plane oriented in the positive Y-axis direction, and is arranged to face the long side wall portion 113 of the container body 110 . The electrode body flat surface 714 is a rectangular flat surface extending parallel to the XZ plane oriented in the negative Y-axis direction, and is arranged to face the long side wall portion 114 of the container body 110 .

Moreover, the electrode body 700 is formed such that the length in the X-axis direction (first direction) is longer than the length in the Z-axis direction (third direction). That is, the distance (maximum distance) between the electrode body curved surfaces 711 and 712 is longer than the length of the electrode body curved surfaces 711 and 712 in the Z-axis direction. In this case, the length of the electrode body flat surfaces 713 and 714 in the X-axis direction may be shorter than the length of the electrode body flat surfaces 713 and 714 in the Z-axis direction. It is preferably formed to be long.

[3 Description of Configuration of Spacer 800]
Next, the configuration of spacer 800 will be described in detail. 4A and 4B are a perspective view and a cross-sectional view showing the configuration of the spacer 800 according to this embodiment. Specifically, (a) of FIG. 4 is an enlarged perspective view showing the spacer 800 on the negative direction side of the X axis shown in FIG. 2, and (b) of FIG. ) is a cross-sectional view showing the configuration of the spacer 800 cut along the IVb-IVb cross section. In FIG. 2, the spacer 800 on the positive side of the X-axis and the spacer 800 on the negative side of the X-axis have the same configuration, so the explanation of the spacer 800 on the positive side of the X-axis is omitted. do.

As shown in FIG. 4( a ), the spacer 800 has a spacer body portion 810 and spacer end portions 820 . The spacer main body portion 810 is a columnar portion extending in the Z-axis direction and having a surface on the X-axis positive direction side that is recessed in a curved shape toward the X-axis negative direction. placed on the direction side. The spacer end portion 820 is a rectangular plate-shaped wall portion located at the end portion of the spacer 800 on the Z-axis positive direction side, and is located on the Z-axis positive direction side of the end portion of the electrode body 700 on the X-axis negative direction side. placed.

Here, as shown in FIG. 4B, the spacer body portion 810 includes a spacer curved surface 811, a spacer first surface 812, a spacer second surface 813, a spacer third surface 814, and a spacer corner portion. 815.

The spacer curved surface 811 is a side surface on the X-axis positive direction side of the spacer main body portion 810, and is curved in a semicircular arc shape so as to protrude in the X-axis negative direction side when viewed from the Z-axis direction. It is a curved surface extending to the The spacer first surface 812 is a side surface of the spacer main body 810 on the negative X-axis direction side, and is a flat surface (flat surface) parallel to the YZ plane and extending in the Z-axis direction. The spacer second surface 813 is a side surface of the spacer main body portion 810 on the Y-axis plus direction side, and is a flat surface (plane) parallel to the XZ plane and extending in the Z-axis direction. The spacer third surface 814 is a side surface of the spacer main body 810 on the Y-axis negative direction side, and is a flat surface (plane) that is parallel to the XZ plane and extends in the Z-axis direction.

The spacer corners 815 are the corners of the spacer body 810 located between the spacer first surface 812 and the spacer second surface 813 and between the spacer first surface 812 and the spacer third surface 814. . In this embodiment, spacer corner 815 has a rounded (curved) shape.

Next, the arrangement position of the spacer 800 within the power storage element 10 (specifically, the positional relationship among the spacer 800, the electrode assembly 700, and the container body 110 of the container 100) will be described in detail. In FIG. 2, the configuration around the spacer 800 on the X-axis plus direction side and the configuration around the spacer 800 on the X-axis minus direction side have the same configuration. Therefore, the configuration around the spacer 800 on the negative side of the X-axis will be described below, and the configuration around the spacer 800 on the positive side of the X-axis will be omitted.

FIG. 5 is a perspective view showing the positional relationship among the spacer 800, the electrode assembly 700, and the container body 110 of the container 100 according to this embodiment. Specifically, FIG. 5 is a perspective view showing components other than the spacer 800, the electrode body 700, and the container body 110 in the energy storage device 10 shown in FIG. 6 and 7 are cross-sectional views showing the positional relationship among the spacer 800, the electrode body 700, and the container body 110 of the container 100 according to this embodiment. Specifically, FIG. 6 is a cross-sectional view showing the configuration when the configuration shown in FIG. 5 is cut along the VI-VI cross section, and FIG. FIG. 10 is a cross-sectional view showing the configuration when cut by .

As shown in these figures (especially FIG. 6), the spacer body portion 810 of the spacer 800 is arranged on the X-axis minus direction side (first direction side) of the electrode body body portion 710 of the electrode body 700 . The short side wall portion 111 (first wall portion) is arranged on the X-axis minus direction side (first direction side) of the spacer body portion 810 of the spacer 800 . Further, the long side wall portion 113 (second wall portion) and the long side wall portion 114 (third wall portion) are adjacent to the short side wall portion 111 (first wall portion) and They are arranged opposite each other. The spacer 800 is arranged in contact with the short side wall portion 111 (first wall portion), the long side wall portion 113 (second wall portion), and the long side wall portion 114 (third wall portion). Furthermore, the electrode body curved surface 711 of the electrode body main portion 710 has a curved shape protruding in the X-axis negative direction side (first direction side) when viewed from the Z-axis direction (third direction). there is

The spacer 800 is arranged in contact with the short side wall portion 111 (first wall portion) and at least one of the long side wall portion 113 (second wall portion) and the long side wall portion 114 (third wall portion). All you have to do is That is, the spacer 800 does not have to be in contact with the long sidewall portion 113 or the long sidewall portion 114 . For example, the spacer 800 may not be in contact with the long side wall portion 113 when the power storage element 10 is manufactured, but may be in contact with the long side wall portion 113 as the electrode body 700 expands. The same applies to the long side wall portion 114 .

The spacer curved surface 811 faces the electrode body curved surface 711 and is disposed in contact with the electrode body curved surface 711 . Specifically, the spacer curved surface 811 extends from a position facing the long side wall portion 113 (second wall portion) of the electrode body curved surface 711 to the long side wall portion 114 when viewed from the Z-axis direction (third direction). It is arranged in continuous contact with the electrode body curved surface 711 up to a position facing the (third wall portion). That is, the spacer curved surface 811 is arranged in continuous contact with the electrode body curved surface 711 from the position P1 facing the long side wall portion 113 to the position P2 facing the long side wall portion 114 .

Here, when viewed from the Z-axis direction (third direction), the spacer curved surface 811 is arranged in continuous contact with an area of 1/2 (50%) or more of the electrode body curved surface 711. Preferably, it is arranged in continuous contact with 2/3 or more of the area, and more preferably in continuous contact with 3/4 or more of the area. This is because the spacer curved surface 811 is preferably placed in contact with a wide area of the electrode body curved surface 711 so that the spacer 800 receives the stress generated when the electrode body 700 expands.

In addition, the spacer curved surface 811 is preferably arranged in continuous contact with an area of 90% or less of the electrode body curved surface 711 when viewed from the Z-axis direction (third direction). It is more preferable to be in continuous contact with the area, and more preferably to be in continuous contact with 80% or less of the area. If the end of the spacer curved surface 811 is extended too much so that the spacer curved surface 811 abuts on many areas of the electrode body curved surface 711 , the end of the spacer main body 810 becomes sharp and damages the electrode body 700 . There is a risk of For this reason, the spacer curved surface 811 is preferably formed so as to abut on a not-too-wide area of the electrode body curved surface 711 .

With such a configuration, the spacer 800 has a shape such that, on the X-axis positive direction side of the contact portion with the electrode body curved surface 711, the distance from the electrode body 700 increases in the X-axis positive direction. That is, the spacer 800 has spacer extension portions 816 and 817 extending in the X-axis plus direction (the direction opposite to the first direction) from the contact portion with the electrode body curved surface 711 .

Spacer extension portion 816 is disposed between long side wall portion 113 and electrode body curved surface 711, contacts long side wall portion 113, and gradually separates from electrode body curved surface 711 in the positive direction of the X axis. It is a part. That is, the spacer extension portion 816 has a cross-sectional shape on the XY plane in which the surface on the Y-axis plus direction side extends parallel to the XZ plane, and the Y-axis minus direction side surface is inclined in the Y-axis direction with respect to the XZ plane. It is a substantially triangular part. Spacer extension portion 817 is arranged between long side wall portion 114 and electrode body curved surface 711, contacts long side wall portion 114, and gradually separates from electrode body curved surface 711 in the positive direction of the X axis. It is a part. That is, the spacer extension portion 817 has a cross-sectional shape on the XY plane in which the surface on the negative Y-axis direction extends parallel to the XZ plane, and the surface on the positive Y-axis direction is inclined in the Y-axis direction with respect to the XZ plane. It is a substantially triangular part.

Further, as shown in FIG. 7, the spacer curved surface 811 continuously extends from one end to the other end of the portion facing the electrode body curved surface 711 in the Z-axis direction (third direction). It is arranged in contact with the surface 711 . That is, since the spacer curved surface 811 has the same length as the electrode body curved surface 711 in the Z-axis direction, the entire spacer curved surface 811 from one end to the other end in the Z-axis direction is the electrode body curved surface 711. It is arranged in contact with the whole from one end to the other end in the Z-axis direction. If the spacer curved surface 811 is shorter than the electrode body curved surface 711 in the Z-axis direction, the entire spacer curved surface 811 from one end to the other end in the Z-axis direction and the electrode body curved surface 711 Z A portion from one end to the other end in the axial direction comes into contact with each other. Further, when the spacer curved surface 811 is longer than the electrode body curved surface 711 in the Z-axis direction, a portion of the spacer curved surface 811 from one end to the other end in the Z-axis direction and the electrode body curved surface 711 All of them from one end to the other end in the Z-axis direction are in contact with each other.

The spacer first surface 812 faces the short side wall portion 111 of the container body 110 of the container 100 and is disposed in contact with the short side wall portion 111 . In this embodiment, the spacer first surface 812 is arranged so that the entire surface is in contact with the short side wall portion 111 . That is, the spacer first surface 812 is arranged in contact with the short side wall portion 111 continuously from one end to the other end of the portion facing the short side wall portion 111 in the Y-axis direction. Furthermore, the spacer first surface 812 is arranged in continuous contact with the short side wall portion 111 from one end to the other end of the portion facing the short side wall portion 111 in the Z-axis direction.

The spacer second surface 813 faces the long side wall portion 113 of the container body 110 and is disposed in contact with the long side wall portion 113 . In the present embodiment, the spacer second surface 813 is arranged so that the entire surface is in contact with the long side wall portion 113 . That is, the spacer second surface 813 is arranged in contact with the long side wall portion 113 continuously from one end to the other end of the portion facing the long side wall portion 113 in the X-axis direction. Furthermore, the spacer second surface 813 is arranged in continuous contact with the long side wall portion 113 from one end to the other end of the portion facing the long side wall portion 113 in the Z-axis direction.

The spacer third surface 814 faces the long side wall portion 114 of the container body 110 and is disposed in contact with the long side wall portion 114 . In this embodiment, the spacer third surface 814 is arranged so that the entire surface is in contact with the long side wall portion 114 . That is, the spacer third surface 814 is arranged in contact with the long side wall portion 114 continuously from one end to the other end of the portion facing the long side wall portion 114 in the X-axis direction. Furthermore, the spacer third surface 814 is arranged in continuous contact with the long side wall 114 from one end to the other end of the portion facing the long side wall 114 in the Z-axis direction.

The spacer corner portion 815 is arranged to face the container corner portion 116 (see FIG. 6) that is the corner portion of the container body 110 of the container 100 . In this embodiment, spacer corner 815 does not abut container corner 116 . That is, the spacer corner portion 815 is not in contact with the container corner portion 116 from one end to the other end of the portion facing the container corner portion 116 in the Z-axis direction. Note that the spacer corner portion 815 may have any shape such as a chamfered shape or a recessed shape. Also, the spacer corner 815 may be arranged wholly or partially in contact with the container corner 116 .

In addition, the spacer end portion 820 is arranged in contact with the end portion of the electrode body 700 on the negative X-axis direction on the positive Z-axis direction side.

[4 Explanation of effects]
As described above, according to the energy storage device 10 according to the embodiment of the present invention, the spacer 800 is formed between the first wall portion (the short side wall portion 111 or 112), the second wall portion, and the third wall portion ( It is arranged in contact with at least one of the long side walls 113 and 114). In addition, the spacer 800 extends from a position of the curved surface (electrode body curved surface 711 or 712) of the electrode body 700 facing the second wall to the third wall when viewed from the third direction (Z-axis direction). They are arranged in contact with each other up to the opposing positions. As described above, the curved surface of the electrode body 700 is in continuous contact with the spacer 800 from the position facing the second wall portion to the position facing the third wall portion. When expanded, the relatively wide surface of the spacer 800 can press against the curved surface to distribute the stress. This prevents the stress from concentrating on the edge of the curved surface of the electrode body 700 (the boundary between the curved electrode body surface 711 or 712 and the electrode body flat surface 713 or 714) and damaging the edge of the curved surface. Since it can be suppressed, damage to the electrode assembly 700 can be suppressed.

In addition, the spacer 800 is arranged in contact with the curved surface of the electrode body 700 from one end to the other end of the portion facing the curved surface in the third direction. In this way, the spacer 800 is in continuous contact with the curved surface from one end to the other end of the portion facing the curved surface, so that the wider surface of the spacer 800 presses the curved surface. can distribute the stress. As a result, it is possible to further suppress damage to the ends of the curved surface caused by concentration of stress on the ends of the curved surface of the electrode assembly 700 , thereby further suppressing damage to the electrode assembly 700 . can.

Further, the electrode body 700 is formed such that the length in the first direction (the X-axis direction, the projecting direction of the curved surface) is longer than the length in the third direction. Specifically, the distance (maximum distance) between the electrode body curved surfaces 711 and 712 is longer than the length of the electrode body curved surfaces 711 and 712 in the Z-axis direction. Thus, in the electrode body 700, since the length in the first direction is long, a large stress is generated in the first direction. Therefore, the effect of dispersing the stress in the first direction by the spacer 800 is large. . In particular, when the length of the electrode body flat surfaces 713 and 714 in the X-axis direction is longer than the length in the Z-axis direction, a larger stress is generated in the first direction. The effect of distributing the stress in one direction is greater. Accordingly, even if the electrode body 700 expands and a large stress is generated in the first direction, the stress can be dispersed by the spacers 800, so that damage to the electrode body 700 can be suppressed.

Further, the electrode body 700 has a configuration in which an electrode body body portion 710 is formed with a curved surface, and the current collector 500 is connected to tab portions 720 and 730 protruding from the electrode body body portion 710 . Here, for example, in the case of an electrode body having a configuration in which the end portion of the curved surface of the electrode body serves as an active material layer non-formed portion and is connected to the current collector 500 (so-called vertically wound electrode body), the curved surface is It is difficult to bring the spacer 800 into close contact with the curved surface because it is likely to be dented and deformed. For this reason, a curved surface is formed on the electrode body body portion 710 of the electrode body 700, and the current collector 500 is connected to the tab portions 720 and 730 of the electrode body 700 (so-called horizontally wound electrode body). With this configuration, even when the current collector 500 is connected to the electrode assembly 700 , the curved surface is less likely to be deformed, and the curved surface can be brought into close contact with the spacer 800 . As a result, the curved surface can be easily pressed by the spacer 800, stress concentration on the edge of the curved surface can be suppressed, and damage to the edge can be suppressed, and the electrode body 700 can be prevented from being damaged. can be suppressed.

Moreover, the spacer 800 is arranged in continuous contact with an area of 50% or more and 90% or less of the curved surface of the electrode body 700 when viewed from the third direction. By arranging the spacer 800 in contact with an area of 50% or more of the curved surface of the electrode body 700 in this way, the curved surface can be pressed by the relatively wide surface of the spacer 800, so that the electrode body 700 expands, the stress can be distributed. Moreover, if the contact area of the spacer 800 with the curved surface is made too large, the tip of the spacer 800 may become sharp and damage the electrode body 700 . It is formed so as to abut on the following areas. These can suppress damage to the electrode body 700 .

In addition, since the spacer 800 has the spacer extending portions 816 and 817 extending in the direction opposite to the first direction (projection direction of the curved surface) from the contact portion with the curved surface of the electrode body 700, , the stress from the electrode body 700 can be received by the spacer extending portions 816 and 817 even when the electrode body 700 expands. As a result, the stress from the electrode body 700 can be distributed to the spacer extending portions 816 and 817, so that damage to the electrode body 700 can be suppressed.

[5 Description of Modifications]
(Modification)
Next, a modification of the above embodiment will be described. 8A and 8B are a perspective view and a cross-sectional view showing the configuration of a spacer 801 according to a modification of this embodiment. Specifically, FIG. 8 is a diagram corresponding to FIG.

As shown in FIG. 8, a spacer 801 according to the present modification is the same as the spacer 800 according to the above-described embodiment, but has a liquid passage 830 formed therein. Other configurations are the same as those of the above embodiment.

The liquid passage 830 is a liquid passage for an electrolytic solution penetrating in the Z-axis direction (third direction), and has a plurality of through holes 831 radially extending from the spacer curved surface 811 when viewed from the Z-axis direction. there is In other words, the liquid passage 830 has a plurality of through holes 831 radially extending from the electrode body curved surface 711 when viewed from the Z-axis direction (third direction).

The through-hole 831 penetrates the spacer end portion 820 of the spacer 801 and the spacer body portion 810 in the Z-axis direction. That is, the through holes 831 are formed in the spacer 801 without forming openings in the spacer curved surface 811 , the spacer first surface 812 , the spacer second surface 813 , the spacer third surface 814 and the spacer corners 815 of the spacer body 810 . passes through.

In this modified example, the liquid passage 830 has ten through-holes 831, but the number of through-holes 831 is not limited, and may be one or more than ten. . The arrangement position of the through-holes 831 is not particularly limited either. The size and shape of the through hole 831 are also not particularly limited.

As described above, according to the power storage device according to this modification, the same effects as those of the above-described embodiment can be obtained. In particular, in this modified example, an electrolytic solution passage 830 is formed through the spacer 801 in the third direction (Z-axis direction). In other words, if the spacers 801 are placed in contact with the three walls of the container 100 and the curved surface of the electrode body 700, the electrolytic solution may not pass through the spacers 801, resulting in poor electrolyte permeability. Therefore, an electrolytic solution passage 830 is formed in the spacer 801 . Thereby, the liquid permeability of the electrolytic solution can be improved. In other words, by causing the electrolyte to flow into the liquid passage 830 , the electrolyte can easily move within the container 100 and excess electrolyte can be stored in the liquid passage 830 .

Further, the electrolyte passage 830 formed in the spacer 801 has a plurality of through holes 831 radially extending from the curved surface of the electrode body 700 . In other words, if the electrolyte passage 830 is formed in the spacer 801 , the spacer 801 may not be able to sufficiently receive the stress when the electrode body 700 expands in the portion of the passage 830 . In particular, the stress when the electrode assembly 700 expands radially spreads from the curved surface. The area that cannot receive sufficient stress becomes large. On the other hand, by forming a plurality of through holes 831 radially extending from the curved surface, the strength against the stress can be increased. Therefore, a plurality of through holes 831 radially extending from the curved surface are formed as the liquid passages 830 . As a result, even if the electrode assembly 700 expands, the stress can be received by the spacers 801 and dispersed, so that the electrode assembly 700 can be prevented from being damaged while improving the electrolyte permeability. be able to.

(Other modifications)
As described above, the power storage device according to the embodiment and its modification of the present invention has been described, but the present invention is not limited to this embodiment and its modification. In other words, the embodiments disclosed this time and their modifications are examples in all respects, and the scope of the present invention is indicated by the scope of claims rather than the above description, and the scope of claims and equivalent meanings and All changes within the scope are included.

For example, in the above-described embodiment and its modification, the spacer curved surface 811 extends continuously from one end to the other end of the portion facing the electrode body curved surface 711 in the Z-axis direction. It was assumed that it was placed in contact with the However, a part of the spacer curved surface 811 facing the electrode body curved surface 711 in the Z-axis direction may not be arranged in contact with the electrode body curved surface 711 . However, the spacer curved surface 811 is preferably placed in contact with the central portion of the electrode body curved surface 711 in the Z-axis direction.

Further, in the above-described embodiment and its modified example, the spacer first surface 812 is arranged so that the entire surface is in contact with the short side wall portion 111 . However, a part of the spacer first surface 812 facing the short side wall portion 111 in the Y-axis direction may not be arranged in contact with the short side wall portion 111 . However, the spacer first surface 812 is preferably disposed in contact with the central portion of the short side wall portion 111 in the Y-axis direction. A part of the spacer first surface 812 facing the short side wall portion 111 in the Z-axis direction may not be placed in contact with the short side wall portion 111 . However, the spacer first surface 812 is preferably disposed in contact with the central portion of the short side wall portion 111 in the Z-axis direction. Similarly, for the spacer second surface 813 , a portion of the portion facing the long side wall portion 113 in the X-axis direction or a portion of the portion facing the long side wall portion 113 in the Z-axis direction is attached to the long side wall portion 113 . It may be arranged that they are not in contact with each other. However, the spacer second surface 813 is preferably disposed in contact with the central portion of the long side wall portion 113 in the Z-axis direction. The same is true for spacer third surface 814 .

In addition, in the above-described embodiment and its modification, the electrode body curved surface 711 has a semicircular arc shape that protrudes in the X-axis direction when viewed from the Z-axis direction. However, the electrode body curved surface 711 can take various shapes such as an arc shape other than a semicircle, or a part of an oval or an ellipse. In this case, the spacer curved surface 811 also has a shape corresponding to the electrode body curved surface 711 .

Further, in the above embodiment and its modified example, the electrode body 700 is formed so that the length in the X-axis direction is longer than the length in the Z-axis direction. However, the electrode body 700 is formed so that the length in the X-axis direction and the length in the Z-axis direction are the same, or the length in the X-axis direction is shorter than the length in the Z-axis direction. may

In the above-described embodiment and its modification, the electrode body 700 is a so-called horizontally wound electrode body that has a winding axis in the Z-axis direction and is formed by winding electrode plates. I decided to However, the configuration of the electrode body 700 is not particularly limited as long as it has a shape having the electrode body curved surface 711. For example, the electrode body 700 may be a so-called vertically wound electrode body having a winding axis in the X-axis direction. Alternatively, the curved surface may be formed by bending a bellows-type electrode body in which the electrode plate is folded into a bellows shape, or a stack-type electrode body in which a plurality of flat plate-like electrode plates are laminated.

Moreover, in the above embodiment and its modification, both the positive electrode side and the negative electrode side have the above configuration. However, the positive electrode side or the negative electrode side may not have the above configuration.

In addition, the form constructed by arbitrarily combining the above embodiment and the above modification is also included in the scope of the present invention.

Moreover, the present invention can be realized not only as such an electric storage element, but also as a spacer included in the electric storage element.

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

10 storage element 100 container 110 container main body 111, 112 short side wall portion 113, 114 long side wall portion 500 current collector 700 electrode body 710 electrode body main body portion 711, 712 electrode body curved surface 713, 714 electrode body flat surface 720, 730 tab Part 740 Positive electrode plate 741, 751 Tab 750 Negative electrode plate 760a, 760b Separator 800, 801 Spacer 810 Spacer main body 811 Spacer curved surface 812 Spacer first surface 813 Spacer second surface 814 Spacer third surface 816, 817 Spacer extension part 830 Liquid passage 831 through hole

Claims (8)

A power storage element comprising an electrode body, a spacer arranged on the first direction side of the electrode body, and a container accommodating the electrode body and the spacer,
The container has a first wall portion disposed on the first direction side of the spacer, and a second wall adjacent to the first wall portion and facing each other in a second direction intersecting the first direction. and a third wall portion,
the electrode body has a curved surface that is curved so as to protrude in the first direction when viewed from a third direction that intersects the first direction and the second direction;
The spacer is
arranged in direct contact with the first wall portion and at least one of the second wall portion and the third wall portion;
When viewed from the third direction, the curved surface is arranged in continuous contact with the curved surface from a position facing the second wall portion to a position facing the third wall portion. storage element. A power storage element comprising an electrode body, a spacer arranged on the first direction side of the electrode body, and a container accommodating the electrode body and the spacer,
The container has a first wall portion disposed on the first direction side of the spacer, and a second wall adjacent to the first wall portion and facing each other in a second direction intersecting the first direction. and a third wall portion,
the electrode body has a curved surface that is curved so as to protrude in the first direction when viewed from a third direction that intersects the first direction and the second direction;
The spacer is
arranged in contact with the first wall portion and at least one of the second wall portion and the third wall portion;
When viewed from the third direction, the curved surface is arranged in continuous contact with the curved surface from a position facing the second wall portion to a position facing the third wall portion. ,
The spacer has an extension portion extending in a direction opposite to the first direction from a contact portion with the curved surface,
The electric storage device, wherein the extending portion has a flat surface facing the curved surface. A power storage element comprising an electrode body, a spacer arranged on the first direction side of the electrode body, and a container accommodating the electrode body and the spacer,
The container has a first wall portion disposed on the first direction side of the spacer, and a second wall adjacent to the first wall portion and facing each other in a second direction intersecting the first direction. and a third wall portion,
the electrode body has a curved surface that is curved so as to protrude in the first direction when viewed from a third direction that intersects the first direction and the second direction;
The spacer is
arranged in contact with the first wall portion and at least one of the second wall portion and the third wall portion;
When viewed from the third direction, the curved surface is arranged in continuous contact with the curved surface from a position facing the second wall portion to a position facing the third wall portion. ,
The energy storage element, wherein the spacer is formed with an electrolytic solution passageway penetrating in the third direction. The electric storage device according to claim 3 , wherein the liquid passage has a plurality of through holes radially extending from the curved surface when viewed from the third direction. 5. The spacer is arranged in contact with the curved surface continuously from one end to the other end of the portion facing the curved surface in the third direction. The storage device according to . The electric storage device according to any one of claims 1 to 5 , wherein the electrode body has a length in the first direction that is longer than a length in the third direction. 7. The electrode assembly according to any one of claims 1 to 6 , comprising: a main body portion having the curved surface; and a tab portion arranged to protrude from a part of the main body portion in the third direction and connected to a current collector. 1. The storage device according to 1. The electric storage device according to any one of claims 1 to 7 , wherein the spacer is arranged in continuous contact with an area of 50% or more and 90% or less of the curved surface when viewed from the third direction.

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