JP7155850B2 - Storage element - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric storage element having an electrode assembly formed by laminating a positive electrode plate, a negative electrode plate, and a separator.

2. Description of the Related Art A power storage element having an electrode assembly formed by laminating a positive electrode plate, a negative electrode plate, and a separator is widely known. For example, Patent Document 1 discloses an electrode laminate (electrode assembly) formed by stacking or winding a positive electrode plate, a negative electrode plate, and a separator. A secondary battery (power storage element) is disclosed in which two ends protrude beyond the positive electrode plate.

JP 2012-43752 A

In the above-described conventional energy storage device, the electrode assembly is formed so that the ends of the separator protrude beyond the electrode plates. For this reason, the conventional energy storage element has a configuration in which the size of the electrode plate in the electrode body is restricted. Improvements are desired.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric storage device capable of improving energy density.

In order to achieve the above object, a power storage element according to one aspect of the present invention is a power storage element including an electrode assembly formed by laminating a positive electrode plate, a negative electrode plate, and a separator, wherein the positive electrode plate and the negative electrode A first plate, which is one of the plates, has a first body portion and a first tab protruding from the first body portion, and a second plate, which is the other of the positive plate and the negative plate, has a , a second body portion, and a second tab projecting from the second body portion, wherein the first body portion projects from a first separator edge, which is an edge of the separator on the first direction side. The second body portion has a protruding portion arranged to protrude from the first separator edge.

According to this, in the electric storage element, the first body portion of the first electrode plate, which is one of the positive electrode plate and the negative electrode plate of the electrode body, does not protrude from the edge of the first separator on the first direction side. The second main body portion of the second electrode plate, which is the other of the negative electrode plates, has a projecting portion projecting from the edge of the first separator. By projecting the second body portion of the second plate from the edge of the first separator in this manner, the size of the second plate can be increased. As a result, the proportion of the electrode plate in the electrode body can be increased, so that the energy density of the storage element can be improved.

Further, the first tab is arranged to protrude from a second separator edge, which is an edge of the separator on the second direction side different from the first direction, and the second main body portion is arranged to protrude from the second separator edge. It may be arranged at a position that does not protrude from the edge.

According to this, in the electrode body, the first tab of the first electrode plate is arranged to protrude from the edge of the second separator on the second direction side different from the first direction, and the second body portion of the second electrode plate are positioned so as not to protrude from the edge of the second separator. In this way, the second main body part does not protrude from the second separator edge, which is the edge of the separator on the first tab side, so that the second main body part comes into contact with the first tab and the first electrode plate and the first electrode plate are separated from each other. It is possible to suppress the occurrence of a short circuit with the bipolar plate. As a result, it is possible to improve the energy density of the storage element while suppressing the occurrence of a short circuit between the electrode plates in the electrode assembly.

Moreover, the projecting portion may be arranged so as to extend along the edge of the first separator.

According to this, in the electrode body, the projecting portion of the second main body portion of the second electrode plate is arranged to extend along the edge of the first separator. By arranging the protruding portion of the second electrode plate so as to extend along the edge of the first separator, the size of the second electrode plate can be increased. can be improved.

In addition, the distance between the edge of the first body portion on the first direction side and the edge of the first separator is the same as the edge of the projecting portion on the first direction side and the edge of the first separator. may be larger than the distance between

According to this, in the electrode assembly, the distance between the edge of the first body portion of the first electrode plate on the first direction side and the edge of the first separator is It is formed larger than the distance between the side edge and the first separator edge. Here, if the first body portion of the first electrode plate protrudes from the edge of the first separator due to contraction of the separator or expansion of the first electrode plate, the first body portion and the second electrode plate A short circuit may occur due to contact with the projecting portion. For this reason, the distance between the edge of the first main body and the edge of the first separator is made larger than the distance between the edge of the projecting portion and the edge of the first separator. As a result, it is possible to prevent the first main body portion from protruding from the edge of the first separator, so that the first main body portion and the projecting portion come into contact with each other to prevent a short circuit between the first electrode plate and the second electrode plate. occurrence can be suppressed.

Further, a restricting member attached to the projecting portion and restricting the movement of the second main body portion may be provided.

According to this, a restricting member is provided which is attached to the projecting portion of the second electrode plate of the electrode body and restricts the movement of the second body portion of the second electrode plate. In this way, the restricting member is attached to the projecting portion to restrict the movement of the second main body, thereby suppressing the displacement of the second electrode plate. As a result, it is possible to suppress the occurrence of a short circuit due to contact between the first electrode plate and the second electrode plate.

Further, the restricting member may be attached so as to straddle the protruding portion and the end portion of the separator on the first direction side.

According to this, the regulating member is attached across the projecting portion of the second electrode plate of the electrode body and the end portion of the separator on the first direction side. As a result, the movement of the second electrode plate with respect to the separator can be restricted, and the displacement of the second electrode plate can be suppressed. can be suppressed.

Moreover, the projecting portion may be arranged so as to project in a direction opposite to the projecting direction of the second tab.

According to this, the protruding portion of the second electrode plate of the electrode body is arranged to protrude in the direction opposite to the direction in which the second tab of the second electrode plate protrudes. Here, in the electrode body, when the second tabs are bundled and joined, the second tabs are pulled together, and when the second tabs are joined to the current collector, the second tabs are pulled. You may be pulled. In this case, since the second main body is pulled toward the second tab, it tends to move toward the second tab. Therefore, in the second electrode plate, the projecting portion to which the restricting member is attached is arranged on the side opposite to the second tab. As a result, the restricting member restricts the movement of the projecting portion, thereby effectively restricting the movement of the second main body portion toward the second tab, thereby further suppressing the displacement of the second electrode plate. can do.

Further, the restricting member may be attached to the protruding portion while being inclined with respect to the first direction.

According to this, the regulating member is attached to the projecting portion in a state of being inclined with respect to the projecting direction of the projecting portion of the second electrode plate. As a result, the contact area between the restricting member and the protruding portion can be increased, so that the movement of the second electrode plate can be more strongly restricted, and the displacement of the second electrode plate can be further suppressed. .

In addition, the present invention can be realized not only as such an electric storage element, but also as an electrode body or a regulating member included in the electric storage element.

ADVANTAGE OF THE INVENTION According to this invention, the electrical storage element which can aim at improvement in energy density can be provided.

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 an exploded perspective view showing a positive electrode plate, a negative electrode plate, and a separator included in an electrode assembly according to an embodiment; FIG. 1 is a plan view showing configurations of a positive electrode plate, a negative electrode plate, and a separator according to an embodiment; FIG. 1 is a cross-sectional view showing the positional relationship between a positive electrode plate, a negative electrode plate, and a separator according to an embodiment; FIG. FIG. 10 is a plan view showing configurations of an electrode body and a regulating member according to Modification 1 of the embodiment; FIG. 7 is a cross-sectional view showing the configuration of an electrode body and a restricting member according to Modification 1 of the embodiment; FIG. 10 is a plan view showing the configuration of an electrode body and a restricting member according to Modification 2 of the embodiment; FIG. 10 is a plan view showing the configuration of an electrode body and a restricting member according to Modification 2 of the embodiment;

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.

Also, in the following description and drawings, the direction in which a pair of electrode terminals (positive electrode side and negative electrode side) of a storage element is arranged, the direction in which a pair of current collectors are arranged, the direction in which a pair of tab bundles of an electrode body are arranged, Alternatively, the direction facing the short sides of the container is defined as the X-axis direction. Also, the facing direction of the long sides of the container, the widthwise direction of the short sides of the container, the thickness direction of the container, or the stacking direction of the electrode plates of the electrode assembly is defined as the Y-axis direction. The direction in which the electrode terminals, current collectors, and electrode bodies are arranged, the direction in which the container body and lid of the storage element are arranged, the longitudinal direction of the short sides of the container, 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.

(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 the storage element 10 may be a laminated storage element.

As shown in FIG. 1 , the energy storage device 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 an electrode body 600 are provided. , is housed. 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 components described above, a spacer arranged on the side of the electrode assembly 600, an insulating film wrapping the electrode assembly 600, and 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 . The container main body 110 is a rectangular cylindrical member that constitutes the main body of the container 100 and has a bottom. The lid 120 is a rectangular plate-like member that constitutes the lid of the container 100 . Further, the lid 120 is provided with a gas discharge valve 121 and the like for discharging the gas inside the container 100 when the internal pressure of the container 100 rises. With such a configuration, the container 100 has a structure in which the interior can be hermetically sealed by, for example, welding the container body 110 and the lid body 120 after the electrode body 600 and the like are accommodated 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. Further, the container 100 may be formed with an injection part for injecting an electrolytic solution therein.

The electrode body 600 is a power storage element (power generation element) that includes a positive electrode plate (positive electrode plate 610 described later), a negative electrode plate (negative electrode plate 620 described later), and a separator (separator 630 described later) and can store electricity. . Specifically, the electrode body 600 is formed in layers so that the separator 630 is sandwiched between the positive electrode plate 610 and the negative electrode plate 620 . Thereby, in the electrode body 600, the positive electrode tab 612 of the positive electrode plate 610 is laminated, and the negative electrode tab 622 of the negative electrode plate 620 is laminated. A detailed description of the configuration of the electrode body 600 will be given later.

Further, the electrode body 600 is provided with a restricting member 640 that fixes the positive electrode plate 610, the negative electrode plate 620, and the separator 630 to each other and restricts their movement. In the present embodiment, two regulation members 640 are arranged on both sides of the electrode body 600 in the X-axis direction, and the positive electrode plate 610, the negative electrode plate 620, and the separator 630 are arranged in the stacking direction (Y direction). axial direction). Specifically, the regulating member 640 is an insulating tape wrapped around the ends of the electrode body 600 in the X-axis direction in a U-shape so as to surround the ends.

The restricting member 640 may be arranged at one position on each side of the electrode body 600 in the X-axis direction, or at three or more positions on both sides of the electrode body 600 in the X-axis direction. Also, the insulating tape used for the regulation member 640 is not particularly limited in material as long as it is a tape having insulating properties. Moreover, the restricting member 640 is not limited to an insulating tape, and a conductive tape may be used as long as the insulation between the positive electrode plate 610 and the negative electrode plate 620 can be secured by an insulating sheet or the like. Also, the restricting member 640 may be, for example, a rigid plate-like member instead of the tape.

The electrode terminal 200 is an electrode terminal electrically connected to the electrode assembly 600 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 (rivet portion) extending downward (the negative direction of the Z axis), and this shaft portion includes the upper gasket 300, the lid body 120, the lower gasket 400, and the current collector. It is inserted into the through hole of the body 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-shaped member that is arranged between the electrode body 600 and the lid body 120 and electrically connects the electrode body 600 and the electrode terminal 200 . Specifically, the current collector 500 on the positive electrode side is joined to the plurality of stacked positive electrode tabs 612 of the electrode assembly 600 by welding or the like, and as described above, is joined to the electrode terminal 200 on the positive electrode side by crimping or the like. be done. 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. In addition, as a method for connecting (joining) the current collector 500 and the positive electrode tab 612 and the negative electrode tab 622, any welding such as ultrasonic bonding, laser welding, or resistance welding may be used. Mechanical joining such as screw fastening may also be used.

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 an insulating material such as polypropylene (PP), polyethylene (PE), or polyphenylene sulfide resin (PPS).

[2 Description of the configuration of the electrode assembly 600]
Next, the configuration of the electrode assembly 600 will be described in detail. FIG. 3 is an exploded perspective view showing the positive electrode plate 610, negative electrode plate 620, and separator 630 included in the electrode assembly 600 according to this embodiment. FIG. 4 is a plan view showing configurations of the positive electrode plate 610, the negative electrode plate 620, and the separator 630 according to this embodiment. Specifically, (a) of FIG. 4 is a plan view showing a state in which the positive electrode plate 610 is stacked on the separator 630, and (b) of FIG. It is a top view which shows the state which carried out. FIG. 5 is a cross-sectional view showing the positional relationship among the positive electrode plate 610, the negative electrode plate 620 and the separator 630 according to this embodiment. Specifically, FIG. 5 is a cross-sectional view showing the configuration when the end portion of the electrode body 600 shown in FIG. 2 on the Z-axis negative direction side is cut along a plane parallel to the YZ plane.

[2.1 Description of Configurations of Positive Electrode Plate 610, Negative Electrode Plate 620, and Separator 630]
As shown in FIG. 3, the electrode assembly 600 is formed by alternately stacking a positive electrode plate 610 and a negative electrode plate 620 with a separator 630 interposed therebetween. In other words, the electrode assembly 600 has the positive electrode plate 610, the separator 630, the negative electrode plate 620, and the separator 630 repeatedly arranged in this order such that the separators 630 are arranged at both ends in the Y-axis direction, and the negative electrode plate 620 is arranged inside the separators 630. Laminated and formed.

By stacking a plurality of positive electrode plates 610 and a plurality of negative electrode plates 620 in this manner, a plurality of positive electrode tabs 612 are stacked and a plurality of negative electrode tabs 622 are stacked. As a result, as shown in FIG. 2, the electrode body 600 is formed with a positive electrode side tab bundle including a plurality of positive electrode tabs 612 and a negative electrode side tab bundle including a plurality of negative electrode tabs 622 . The positive electrode side tab bundle and the negative electrode side tab bundle are joined to the positive electrode side and negative electrode side current collectors 500 by welding or the like, and are electrically connected to the positive electrode side and the negative electrode side electrode terminals 200 . The configurations of the positive electrode plate 610, the negative electrode plate 620, and the separator 630 will be described in more detail below.

As shown in FIGS. 4A and 5, the positive electrode plate 610 has a positive electrode body portion 611 and a positive electrode tab 612 . The positive electrode main body 611 is a rectangular, flat plate-like portion that constitutes the main body of the positive electrode plate 610 and is elongated in the X-axis direction, and has a positive electrode base material 614a and a positive electrode mixture layer 614b. The positive electrode tab 612 is a rectangular tab that protrudes in the positive Z-axis direction from a portion of the positive electrode main body 611 on the negative X-axis direction and the positive Z-axis direction, and is formed integrally with the positive electrode substrate 614a. That is, the positive electrode base material 614a and the positive electrode tab 612 are collector foils made of aluminum or an aluminum alloy, and the positive electrode mixture layer 614b is arranged on the surfaces (both sides) of the positive electrode base material 614a. The positive electrode plate 610 is an example of a first electrode plate, the positive electrode body portion 611 is an example of a first body portion, and the positive electrode tab 612 is an example of a first tab.

As current collector foils constituting the positive electrode substrate 614a and the positive electrode tab 612, appropriately known materials such as nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, and Al—Cd alloy are used. can also be used. Also, the positive electrode mixture layer 614b contains a positive electrode active material, a conductive aid, and a binder. As the positive electrode active material used for the positive electrode mixture layer 614b, any known material can be appropriately used as long as it is a positive electrode active material capable of intercalating and deintercalating lithium ions. 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. The type of conductive aid used in the positive electrode mixture layer 614b is not particularly limited, and may be metallic or non-metallic. As the binder used for the positive electrode mixture layer 614b, any material that is stable against the solvent and electrolytic solution used during electrode production and against oxidation-reduction reactions during charging and discharging can be used. Not restricted.

4B and 5, the negative electrode plate 620 has a negative electrode body portion 621 and a negative electrode tab 622. As shown in FIG. The negative electrode main body 621 is a rectangular and flat plate-like portion that constitutes the main body of the negative electrode plate 620 and is elongated in the X-axis direction, and has a negative electrode base material 624a and a negative electrode mixture layer 624b. The negative electrode tab 622 is a rectangular tab that protrudes in the positive Z-axis direction from a portion of the negative electrode main body 621 on the positive side of the X-axis and the positive side of the Z-axis, and is formed integrally with the negative electrode substrate 624a. That is, the negative electrode base material 624a and the negative electrode tab 622 are collector foils made of copper, copper alloy, or the like, and the negative electrode mixture layer 624b is arranged on the surface (both sides) of the negative electrode base material 624a. The negative electrode plate 620 is an example of a second electrode plate, the negative electrode body portion 621 is an example of a second body portion, and the negative electrode tab 622 is an example of a second tab.

It should be noted that, as the current collector foils forming the negative electrode substrate 624a and the negative electrode tab 622, the same material as the current collector foils forming the positive electrode substrate 614a and the positive electrode tab 612 can be used. In addition, the negative electrode mixture layer 624b contains a negative electrode active material, a conductive aid, and a binder. As the negative electrode active material used for the negative electrode mixture layer 624b, any known material can be appropriately used as long as it is a negative electrode active material capable of intercalating and deintercalating lithium ions. For example, as the negative electrode active material, lithium metal, lithium alloys (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and alloys containing lithium metal such as Wood's alloy) In addition, 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. be done. The conductive aid and binder used for the negative electrode mixture layer 624b are the same as the conductive aid and binder used for the positive electrode mixture layer 614b, and thus detailed description thereof is omitted.

The separator 630 is a flat, rectangular, microporous sheet made of resin, for example, elongated in the X-axis direction. As the material of the separator 630, any known material can be appropriately used as long as it does not impair the performance of the storage element 10. FIG. For example, as the separator 630, a woven fabric, a non-woven fabric, or a synthetic resin microporous film made of a polyolefin resin such as polyethylene, which is insoluble in an organic solvent, can be used. The separator 630 is formed by laminating a plurality of microporous membranes having different materials, weight-average molecular weights, and porosities, and adding additives such as various plasticizers, antioxidants, and flame retardants to these microporous membranes. It may be one containing an appropriate amount, or one coated with an inorganic oxide such as silica on one or both sides of these microporous membranes. In particular, as the separator 630, a synthetic resin microporous film can be preferably used. Polyolefin-based microporous membranes such as polyolefin-based microporous membranes are preferably used in terms of thickness, membrane strength, membrane resistance, and the like.

[2.2 Description of Positional Relationship Between Positive Electrode Plate 610, Negative Electrode Plate 620, and Separator 630]
Here, in the positive electrode body portion 611, the edge on the Z-axis negative direction side is defined as a first positive electrode edge 611a, the edge on the Z-axis positive direction side is defined as a second positive electrode edge 611b, and the edge on the X-axis negative direction side is defined as a first positive electrode edge 611a. The edge is a third positive edge 611c, and the edge on the positive side of the X axis is a fourth positive edge 611d. In the negative electrode body portion 621, the edge on the negative side of the Z-axis is defined as a first negative electrode edge 621a, the edge on the positive side of the Z-axis is defined as a second negative electrode edge 621b, and the edge on the negative side of the X-axis. is a third negative electrode edge 621c, and the edge on the X-axis plus direction side is a fourth negative electrode edge 621d. Furthermore, in the separator 630, the edge on the negative side of the Z axis is a first separator edge 630a, the edge on the positive side of the Z axis is a second separator edge 630b, and the edge on the negative side of the X axis is a second separator edge 630a. A third separator edge 630c is used, and an edge on the X-axis plus direction side is a fourth separator edge 630d. The negative Z-axis direction is an example of a first direction, and the positive Z-axis direction is an example of a second direction different from the first direction.

In such a configuration, the first positive electrode edge 611a is arranged on the Z-axis positive direction side of the first separator edge 630a. In other words, the positive electrode body portion 611 is arranged at a position that does not protrude from the first separator edge 630a that is the edge of the separator 630 on the Z-axis negative direction (first direction) side. Also, the first negative electrode edge 621a is arranged on the Z-axis negative direction side of the first separator edge 630a. That is, the negative electrode body portion 621 is arranged to protrude from the first separator edge 630a. Thus, the negative electrode body portion 621 has a protruding portion 623 protruding from the first separator edge 630a in the negative Z-axis direction.

Specifically, the projecting portion 623 is arranged to extend along the first separator edge 630a. That is, the protruding portion 623 is the end portion of the negative electrode body portion 621 on the negative Z-axis direction side and is an elongated portion extending in the X-axis direction. In other words, the protrusion 623 is arranged to protrude in the direction opposite to the direction in which the negative electrode tab 622 protrudes.

Here, the distance A between the first positive electrode edge 611a and the first separator edge 630a is made larger than the distance B between the first negative electrode edge 621a and the first separator edge 630a. . That is, the distance (distance A) between the edge of the positive electrode body portion 611 on the negative Z-axis direction side and the first separator edge 630a is the same as the edge of the projecting portion 623 on the negative Z-axis direction side and the first separator edge greater than the distance (distance B) to edge 630a.

Note that, as shown in FIG. 5, the first positive electrode edge 611a includes a positive electrode substrate edge 615a, which is the edge of the positive electrode substrate 614a on the negative Z-axis direction side, and and the positive electrode composite material edge 615b, which is the side edge. The first negative electrode edge 621a is the negative electrode substrate edge 625a, which is the edge of the negative electrode substrate 624a on the negative Z-axis direction side, and the negative electrode substrate edge 625a, which is the edge of the negative electrode mixture layer 624b on the negative Z-axis direction side. The composite material edge 625b is configured.

However, when the positive electrode base material edge 615a and the positive electrode composite material edge 615b are not parallel to the Y-axis direction and have a shape protruding in the negative Z-axis direction, the point closest to the negative Z-axis direction (the point closest to the first separator edge 630a in the Z-axis direction) is defined as the first positive electrode edge 611a. For example, when the positive electrode substrate edge 615a and the positive electrode composite material edge 615b are arranged at different positions in the Z-axis direction, the edge on the Z-axis negative direction side is defined as the first positive electrode edge 611a. . When the edge on the negative Z-axis direction is inclined or curved from the Y-axis direction, the edge on the negative Z-axis direction that is closest to the negative Z-axis direction is the first positive edge. Define extreme edge 611a.

Similarly, when the negative electrode base material edge 625a and the negative electrode composite material edge 625b are not parallel to the Y-axis direction and have a shape protruding in the negative Z-axis direction, The location (the location farthest from the first separator edge 630a in the Z-axis direction) is defined as the first negative electrode edge 621a. For example, when the negative electrode substrate edge 625a and the negative electrode composite material edge 625b are arranged at different positions in the Z-axis direction, the edge on the Z-axis negative direction side is defined as the first negative electrode edge 621a. . In addition, when the edge on the negative Z-axis direction side is inclined or curved from the Y-axis direction, the edge on the negative Z-axis direction side that is closest to the negative Z-axis direction is the first negative side edge. Define extreme edge 621a.

Also, the second positive electrode edge 611b is arranged on the Z-axis negative direction side of the second separator edge 630b. In other words, the positive electrode body portion 611 is arranged at a position that does not protrude from the second separator edge 630b that is the edge of the separator 630 on the Z-axis positive direction (second direction) side. In addition, the second negative electrode edge 621b is arranged on the Z-axis negative direction side of the second separator edge 630b, and is arranged on the Z-axis positive direction side of the second positive electrode edge 611b. That is, the negative electrode body portion 621 is arranged at a position that does not protrude from the second separator edge 630b and that protrudes from the second positive electrode edge 611b.

Further, the positive electrode tab 612 is arranged to protrude from the second positive electrode edge 611b, cross the separator 630, and protrude from the second separator edge 630b. The negative electrode tab 622 is arranged to protrude from the second negative electrode edge 621b, cross the separator 630, and protrude from the second separator edge 630b.

Also, the third positive electrode edge 611c is arranged on the X-axis positive direction side of the third separator edge 630c. That is, the positive electrode body portion 611 is arranged at a position that does not protrude from the third separator edge 630c that is the edge of the separator 630 on the negative side of the X axis. Also, the third negative electrode edge 621c is arranged on the X-axis positive direction side of the third separator edge 630c, and is arranged on the X-axis negative direction side of the third positive electrode edge 611c. In other words, the negative electrode body portion 621 is arranged at a position that does not protrude from the third separator edge 630c and at a position that protrudes from the third positive electrode edge 611c. The same applies to the positional relationship among the fourth positive electrode edge 611d, the fourth negative electrode edge 621d, and the fourth separator edge 630d.

[3 Explanation of effects]
As described above, according to the energy storage device 10 according to the embodiment of the present invention, the positive electrode main body portion 611 (first main body portion) of the positive electrode plate 610 (first electrode plate) of the electrode assembly 600 is arranged in the negative Z-axis direction. The negative electrode main body portion 621 (second main body portion) of the negative electrode plate 620 (second electrode plate) does not protrude from the first separator edge 630a on the (first direction) side, and protrudes from the first separator edge 630a. It has a portion 623 . By protruding the negative electrode body portion 621 of the negative electrode plate 620 from the first separator edge 630a in this way, the size of the negative electrode plate 620 can be increased. As a result, the ratio of the electrode plates in the electrode body 600 can be increased, so that the energy density of the storage element 10 can be improved.

Further, in the electrode body 600, the positive electrode tab 612 (first tab) of the positive electrode plate 610 is arranged to protrude from the second separator edge 630b on the Z-axis positive direction (second direction different from the first direction) side, The negative electrode body portion 621 of the negative electrode plate 620 is arranged at a position that does not protrude from the second separator edge 630b. In this way, the negative electrode body portion 621 does not protrude from the second separator edge 630 b , which is the edge of the separator 630 on the positive electrode tab 612 side, so that the negative electrode body portion 621 abuts on the positive electrode tab 612 and contacts the positive electrode plate 610 . It is possible to suppress the occurrence of a short circuit with the negative electrode plate 620 . As a result, it is possible to improve the energy density of the storage element 10 while suppressing the occurrence of a short circuit between the electrode plates in the electrode body 600 .

In the electrode body 600, the projecting portion 623 of the negative electrode body portion 621 of the negative electrode plate 620 is arranged to extend along the first separator edge 630a. By arranging the projecting portion 623 of the negative electrode plate 620 so as to extend along the first separator edge 630a in this manner, the size of the negative electrode plate 620 can be increased. can be improved.

In the electrode body 600, the distance between the edge of the positive electrode body portion 611 of the positive electrode plate 610 on the negative Z-axis direction side and the first separator edge 630a It is formed larger than the distance between the side edge and the first separator edge 630a. Here, if the positive electrode main body portion 611 of the positive electrode plate 610 protrudes from the first separator edge 630a due to contraction of the separator 630 or expansion of the positive electrode plate 610, the positive electrode main body portion 611 and the negative electrode plate 620 protrude. 623, and a short circuit may occur. Therefore, the distance between the edge of the positive electrode body portion 611 and the first separator edge 630a is made larger than the distance between the edge of the projecting portion 623 and the first separator edge 630a. As a result, it is possible to prevent the positive electrode main body 611 from protruding from the first separator edge 630a, so that the positive electrode main body 611 and the projecting portion 623 come into contact with each other, causing a short circuit between the positive electrode plate 610 and the negative electrode plate 620. can be suppressed.

[4 Description of modified example]
(Modification 1)
Next, Modification 1 of the above embodiment will be described. FIG. 6 is a plan view showing configurations of an electrode body 600 and a regulation member 641 according to Modification 1 of the present embodiment. Specifically, FIG. 6 is a front view showing the configuration when the regulation member 641 is attached to the electrode body 600 as seen from the Y-axis negative direction side. FIG. 7 is a cross-sectional view showing configurations of an electrode body 600 and a regulation member 641 according to Modification 1 of the present embodiment. Specifically, FIG. 7 is a cross-sectional view showing the configuration when the electrode body 600 and the regulating member 641 shown in FIG. 6 are cut along the VII-VII cross section, and corresponds to FIG.

As shown in FIGS. 6 and 7, a regulation member 641 is attached to the electrode body 600 in this modification instead of the regulation member 640 in the above embodiment. Other configurations are the same as those of the above embodiment.

The regulating member 641 is a member that is attached to the protruding portion 623 of the negative electrode main body portion 621 of the negative electrode plate 620 to regulate the movement of the negative electrode main body portion 621 . That is, the restricting member 641 is attached to the projecting portion 623 projecting in the direction opposite to the projecting direction of the negative electrode tab 622 . Specifically, the regulating member 641 is attached across the projecting portion 623 and the end portion of the separator 630 on the negative Z-axis direction side.

More specifically, the regulating member 641 extends in the X-axis direction at the end of the electrode body 600 on the negative Z-axis direction, and extends from the X-axis direction to the end so as to surround the end. It is wound and arranged in a U shape when viewed. That is, the regulating member 641 is arranged across the positive electrode plate 610 and the negative electrode plate 620 so as to connect the ends of the separators 630 on both ends in the Y-axis direction on the negative Z-axis direction side in the X-axis direction. ing.

Here, the regulating member 641 is an insulating tape or the like, like the regulating member 640 in the above embodiment. That is, the regulating member 641 is affixed across the protruding portions 623 of the negative electrode plates 620 and the ends of the separators 630 at both ends in the Y-axis direction, and the first negative ends of the plurality of negative electrode plates 620 arranged in the Y-axis direction. It is attached to the edge 621a. Note that the regulating member 641 does not have to be attached to the first negative electrode edges 621a of all the negative electrode plates 620 because the protrusions 623 of the negative electrode plates 620 have different protrusion amounts. Also, the restricting member 641 may not be attached across the protrusion 623 and the end of the separator 630 at one end of the Y-axis direction ends.

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, a restricting member 641 is provided which is attached to the projecting portion 623 of the negative electrode plate 620 of the electrode body 600 to restrict the movement of the negative electrode body portion 621 of the negative electrode plate 620 . In this way, the restricting member 641 is attached to the protruding portion 623 to restrict the movement of the negative electrode body portion 621, thereby suppressing the negative electrode plate 620 from shifting. As a result, it is possible to suppress the occurrence of a short circuit due to contact between the positive electrode plate 610 and the negative electrode plate 620 .

In addition, the regulation member 641 is attached across the projecting portion 623 of the negative electrode plate 620 of the electrode body 600 and the end portion of the separator 630 on the negative Z-axis direction side. This restricts the movement of the negative electrode plate 620 with respect to the separator 630, thereby suppressing the displacement of the negative electrode plate 620, thereby suppressing the occurrence of a short circuit due to contact between the positive electrode plate 610 and the negative electrode plate 620. be able to.

Also, the protruding portion 623 of the negative electrode plate 620 of the electrode body 600 is arranged to protrude in the direction opposite to the direction in which the negative electrode tab 622 (second tab) of the negative electrode plate 620 protrudes. Here, in the electrode body 600 , when the negative electrode tabs 622 are bundled and joined together, the negative electrode tabs 622 are pulled together by gathering the negative electrode tabs 622 together, and when the negative electrode tabs 622 are joined to the current collector 500 , the negative electrode tabs 622 are pulled. 622 may be pulled. In this case, since the negative electrode main body 621 is pulled toward the negative electrode tab 622 side, it is likely to move toward the negative electrode tab 622 side. Therefore, in the negative electrode plate 620 , the projecting portion 623 to which the restricting member 641 is attached is arranged on the side opposite to the negative electrode tab 622 . As a result, the restriction member 641 restricts the movement of the protruding portion 623 , thereby effectively restricting the movement of the negative electrode body portion 621 toward the negative electrode tab 622 , thereby further preventing the negative electrode plate 620 from being displaced. can be suppressed.

(Modification 2)
Next, Modification 2 of the above embodiment will be described. 8 and 9 are plan views showing configurations of the electrode body 600 and the restricting members 642 to 645 according to Modification 2 of the present embodiment. Specifically, FIGS. 8 and 6 are diagrams corresponding to FIG.

As shown in FIGS. 8 and 9, the electrode body 600 in this modified example is provided with regulating members 642 to 645 instead of the regulating member 641 in the first modified example. Other configurations are the same as those of the above-described embodiment or modification 1. In other words, this modified example shows various forms in which the method of attaching the regulating member to the electrode body 600 is changed. Note that the regulating members 642 to 645 are insulating tapes or the like, like the regulating members 640 and 641 in the above embodiment and modification 1. FIG.

As shown in FIG. 8, the restricting member 642 is formed in a U-shape when viewed from the X-axis direction so as to surround a portion of the end portion of the electrode body 600 on the negative Z-axis direction side. It is wrapped and arranged. That is, the restricting member 642 has a shape obtained by shortening the restricting member 641 in Modification 1 in the X-axis direction.

Moreover, the restricting members 643 and 644 are attached to the projecting portion 623 while being inclined with respect to the Z-axis minus direction (first direction). In other words, the restricting member 643 is obliquely wound around the end of the electrode body 600 in the negative Z-axis direction so as to surround the end. In addition, the restricting member 644 is disposed so as to surround the end portions of the electrode body 600 on the negative Z-axis direction side and the positive X-axis direction side so as to surround the ends. That is, the regulating member 644 is wound around the corner of the electrode body 600 and presses (compresses) the corner of the electrode body 600 in the Y-axis direction.

As a result, the regulating members 642 to 644 are affixed across the projecting portions 623 of the negative electrode plates 620 and the ends of the separators 630 at both ends in the Y-axis direction. It is attached to the one negative electrode edge 621a. Note that the regulating members 642 to 644 do not have to be attached to the first negative electrode edges 621a of all the negative electrode plates 620, as in the first modification. Further, the regulating members 642 to 644 do not need to be attached across the protruding portion 623 and the end of the separator 630 at one end of the Y-axis direction ends.

FIG. 8 shows various forms of regulating members that can be attached to the electrode assembly 600. In what combination are the regulating members 642 to 644 attached to the electrode assembly 600? may In other words, any one of the regulating members 642 to 644 may be attached to the electrode body 600, and the attachment position is not particularly limited. Moreover, a plurality of any of the regulation members 642 to 644 may be attached to the electrode assembly 600 .

Further, as shown in FIG. 9 , the regulation member 645 is wound around the electrode body 600 so as to surround the entire surface of the electrode body 600 . In this modification, the regulating member 645 is wrapped around the electrode body 600 once in the X-axis direction (around the Z-axis) to press (compress) the electrode body 600 in the Y-axis direction. The restricting member 645 may be wound around the electrode body 600 any number of times, or may be wound around the electrode body 600 in the Z-axis direction (around the X-axis).

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, the regulating members 643 and 644 are attached to the protruding portion 623 of the negative electrode plate 620 while being inclined with respect to the protruding direction of the protruding portion 623 . As a result, the contact area between the regulating members 643 and 644 and the projecting portion 623 can be increased, so that the movement of the negative electrode plate 620 can be more strongly regulated, and the displacement of the negative electrode plate 620 can be further suppressed. can be done. In addition, the regulating member 644 is wound around the corner of the electrode body 600 and presses (compresses) the corner, and the regulating member 645 is wrapped around the entire circumference of the electrode body 600 and presses the entire electrode body 600 . (pressing). Therefore, the restricting members 644 and 645 can effectively suppress the expansion (expansion) of the electrode body 600 in the Y-axis direction while suppressing the negative electrode plate 620 from being displaced.

(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 embodiment and its modification, the positive electrode plate 610 of the electrode assembly 600 is an example of the first electrode plate, and the negative electrode plate 620 is an example of the second electrode plate. However, the positive electrode plate 610 may be an example of the second electrode plate, and the negative electrode plate 620 may be an example of the first electrode plate. In this case, the positive electrode body portion 611 is an example of the second body portion, the positive electrode tab 612 is an example of the second tab, the negative electrode body portion 621 is an example of the first body portion, and the negative electrode tab 622 is an example of the first tab. An example.

Further, in the above-described embodiment and its modification, the Z-axis minus direction is used as an example of the first direction, and the Z-axis plus direction is used as an example of the second direction. However, the first direction and the second direction may be any combination of directions as long as they are directions different from each other. For example, if the first direction is the negative direction of the Z-axis, the second direction may be the positive direction of the X-axis or the negative direction of the X-axis. Moreover, when the second direction is the positive direction of the Z-axis, the first direction may be the positive direction of the X-axis or the negative direction of the X-axis. That is, for example, the positive electrode tab 612 or the negative electrode tab 622 may protrude in the positive direction of the X-axis or may protrude in the negative direction of the X-axis. Also, the protruding portion 623 of the negative electrode plate 620 may protrude in the positive direction of the X-axis or may protrude in the negative direction of the X-axis. That is, the protruding portion 623 may be arranged to protrude in at least one of the X-axis positive direction side and the X-axis negative direction side instead of or in addition to the Z-axis negative direction side. . Furthermore, when the positive electrode plate 610 and the negative electrode plate 620 are short-circuited, the first direction and the second direction may be the same direction. In other words, the protruding portion 623 may protrude in the same direction as the positive electrode tab 612 or the negative electrode tab 622 .

In addition, in the above-described embodiment and its modification, all the negative electrode plates 620 have the projecting portion 623 projecting from the first separator edge 630a. However, any one of the negative electrode plates 620 may not protrude from the first separator edge 630a and may not have the projecting portion 623 .

In addition, in the above-described embodiment and its modification, the entire end portion of the negative electrode plate 620 on the Z-axis negative direction side protrudes from the first separator edge 630a and extends along the first separator edge 630a. It is assumed that a projecting portion 623 is formed. However, only a part of the end of the negative electrode plate 620 on the Z-axis negative direction side protrudes from the first separator edge 630a, and the projecting portion 623 does not extend along the first separator edge 630a. can be

Further, in the above embodiment and its modification, the distance A between the first positive electrode edge 611a and the first separator edge 630a is equal to the distance between the first negative electrode edge 621a and the first separator edge 630a. It is assumed to be larger than the distance B. However, the distance A may be the same as the distance B or may be smaller than the distance B.

In addition, in the above-described embodiment and its modifications, all of the negative electrode plates 620 have the negative electrode mixture layers 624b on both sides of the negative electrode substrate 624a. However, the outermost negative electrode plate 620 (the negative electrode plate 620 at the end in the Y-axis direction) of the negative electrode plates 620 may not have the negative electrode mixture layer 624b on the outer surface of the negative electrode substrate 624a. . That is, the negative electrode plate 620 closest to the Y-axis positive direction may not have the negative electrode mixture layer 624b on the surface of the negative electrode substrate 624a facing the Y-axis positive direction, The plate 620 may not have the negative electrode mixture layer 624b on the surface of the negative electrode substrate 624a on the Y-axis negative direction side.

In addition, in the above embodiment and its modification, the electrode assembly 600 has the negative electrode plate 620 as the outermost electrode plate, but the positive electrode plate 610 may be the outermost electrode plate. .

Further, in the above embodiment and its modification, the positive electrode plate 610 and the negative electrode plate 620 have a rectangular shape elongated in the X-axis direction. However, the positive electrode plate 610 and the negative electrode plate 620 may have a rectangular shape elongated in the Z-axis direction, other polygonal shapes, an elliptical shape, an elliptical shape, a circular shape, and the shape thereof is not particularly limited.

Further, in the above-described embodiment and its modification, the positive electrode plate 610 and the negative electrode plate 620 have the rectangular positive electrode tab 612 and negative electrode tab 622 . However, the shapes of the positive electrode tab 612 and the negative electrode tab 622 are not particularly limited, and may be any shape such as a polygonal shape other than a rectangular shape, a semicircular shape, a semielliptical shape, a semielliptical shape, and the like. Also, the positive electrode tab 612 and the negative electrode tab 622 may be tabs in which the entire electrode plate protrudes instead of a tab in which a part of the electrode plate protrudes.

Further, in the modified example, the regulating members 641 to 645 are attached across the projecting portion 623 and the end portion of the separator 630 . However, the regulating members 641 to 645 may be attached to the projecting portion 623 without being attached to the separator 630 .

In the above embodiment and its modification, the electrode body 600 is a stacked electrode body formed by laminating the positive electrode plate 610, the negative electrode plate 620, and the separator 630. As shown in FIG. However, the electrode body 600 may be a bellows-shaped electrode body in which an electrode plate is folded into a bellows shape, or a wound electrode body formed by winding an electrode plate.

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.

In addition, the present invention can be realized not only as such a power storage element, but also as the electrode body 600 or the regulation members 641 to 645 included in the power storage element.

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

10 storage element 600 electrode body 610 positive plate 611 positive electrode body 611a first positive electrode edge 611b second positive electrode edge 612 positive electrode tab 620 negative electrode plate 621 negative electrode body 621a first negative electrode edge 621b second negative electrode edge 622 negative electrode tab 623 protrusion 630 separator 630a first separator edge 630b second separator edge 640, 641, 642, 643, 644, 645 regulating member

Claims (7)

A storage element comprising an electrode body formed by laminating a positive electrode plate, a negative electrode plate, and a separator,
a first electrode plate, which is one of the positive electrode plate and the negative electrode plate, has a first body portion and a first tab projecting from the first body portion;
A second electrode plate, which is the other of the positive electrode plate and the negative electrode plate, has a second body portion and a second tab projecting from the second body portion,
The first main body portion is arranged at a position that does not protrude from the first separator edge, which is the edge of the separator on the first direction side,
The second main body has a protrusion arranged to protrude from the edge of the first separator,
The two separators facing each other with the first electrode plate interposed therebetween are arranged without being joined at their ends on the first direction side,
The distance between the edge of the first body portion on the first direction side and the edge of the first separator is the distance between the edge of the projecting portion on the first direction side and the edge of the first separator. greater than the distance of
storage device. The first tab is arranged to protrude from a second separator edge, which is an edge of the separator on a second direction side different from the first direction,
The electric storage element according to claim 1, wherein the second body portion is arranged at a position not protruding from the edge of the second separator. The electric storage element according to claim 1 or 2, wherein the projecting portion is arranged to extend along the edge of the first separator. moreover,
The electric storage device according to any one of claims 1 to 3 , further comprising a restricting member attached to the protruding portion to restrict movement of the second body portion. The electric storage device according to claim 4 , wherein the regulating member is attached across the projecting portion and the end portion of the separator on the first direction side. The electric storage element according to claim 4 or 5 , wherein the projecting portion is arranged to project in a direction opposite to the projecting direction of the second tab. The electric storage device according to any one of claims 4 to 6 , wherein the regulating member is attached to the projecting portion while being inclined with respect to the first direction.

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