Energy storage element

Abstract

To provide a power storage element capable of suppressing damages of an electrode body.SOLUTION: A power storage element 10 comprises: an electrode body 600 on which a positive electrode board and a negative electrode board are laminated; a first collector body 400 connected to a first electrode board 630 of one polarity of the positive electrode board and the negative electrode board; a second collector body 500 connected to a second electrode board 650 of the other polarity; a first electrode terminal 200 connected to the first collector body 400; and a second electrode terminal 300 connected to the second collector body 500. The electrode body 600 is a connection part of an electrode main body part 601 and the first collector body 400 of the first electrode board 630, and includes: a first connection part 631a projected to a first direction (a Z-axial direction) from the electrode main body part 601; and a second connection part 651a as a connection part with the second collector body 500 of the second electrode board 650 and projected to a second direction (a X-axial direction) crossed to the first direction from the electrode main body part 601. The first electrode terminal 200 and the second electrode terminal 300 are arranged on the same side of the electrode body 600.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an energy storage element including an electrode assembly and a current collector connected to the electrode assembly. [Background technology]

[0002] There is widely known an electric storage element including an electrode body in which positive and negative plates are stacked, and a pair of current collectors connected to the positive and negative plates of the electrode body, respectively. For example, Patent Document 1 discloses a secondary battery (electric storage element) in which a positive conductive member and a negative conductive member (a pair of current collectors) are connected to the positive and negative electrodes (positive and negative plates) of the electrode assembly (electrode body), respectively. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-216119 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described conventional energy storage element, the positive and negative plates of the electrode body are connected to a pair of current collectors above the electrode body, and therefore, although the pair of current collectors above the electrode body have a function of protecting the electrode body, there is a risk of the electrode body being damaged if an external impact is applied to the side of the electrode body.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and has an object to provide an energy storage element capable of suppressing damage to an electrode body. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, an energy storage element according to one embodiment of the present invention comprises an electrode body in which positive and negative electrode plates are stacked, a first current collector connected to a first electrode plate of one polarity among the positive and negative electrode plates, and a second current collector connected to a second electrode plate of the other polarity, a first electrode terminal connected to the first current collector, and a second electrode terminal connected to the second current collector, wherein the electrode body has a main body portion, a first connection portion which is a connection portion of the first electrode plate with the first current collector and protrudes from the main body portion in a first direction, and a second connection portion which is a connection portion of the second electrode plate with the second current collector and protrudes from the main body portion in a second direction intersecting the first direction, and the first electrode terminal and the second electrode terminal are arranged on the same side of the electrode body.

[0007] According to this, in the energy storage element, the electrode body has a first connection part with the first current collector of the first electrode plate protruding in a first direction, and a second connection part with the second current collector of the second electrode plate protruding in a second direction, and the first electrode terminal and the second electrode terminal are arranged on the same side of the electrode body. In this way, the first connection part of the first electrode plate of the electrode body protrudes in the first direction to connect with the first current collector, and the second connection part of the second electrode plate protrudes in the second direction to connect with the second current collector. As a result, since the current collectors are arranged in both the first direction and the second direction of the electrode body, it is possible to improve protection of the electrode body in both the first direction and the second direction. Therefore, even if an impact is applied from the outside to the electrode body in both the first direction and the second direction, damage to the electrode body can be suppressed.

[0008] In addition, the first and second connection parts of the electrode body protrude in different directions, and if the first and second electrode terminals are also arranged in different directions accordingly, problems such as difficulty in connecting the storage element to other devices will occur. For this reason, the first and second electrode terminals are arranged on the same side of the electrode body. This simplifies the system configuration, such as making it easier to connect the storage element to other devices. In this way, problems caused by the first and second connection parts of the electrode body protruding in different directions can be suppressed.

[0009] The first connection portion may protrude from an end of the main body portion opposite to the end of the second connection portion.

[0010] According to this, in the electrode body, the first connection part is protruded from the end of the main body part opposite to the second connection part, so that the first connection part and the second connection part are arranged at positions apart from each other. This makes it possible to reduce the risk of a short circuit occurring due to the first connection part and the second connection part (or the first current collector and the second current collector) coming close to each other even in an abnormal state such as when an external impact is applied.

[0011] In addition, the electrode body may further include a folded separator formed by folding back a single separator, the folded separator having two separator portions that sandwich the first electrode plate and a separator folded portion that connects the ends of the two separator portions, and the second connection portion may be arranged to protrude from the separator folded portion.

[0012] According to this, in the electrode body, the folded separator has a separator folded portion that connects the ends of the two separator portions that sandwich the first electrode plate, and the second connection portion is arranged to protrude from the separator folded portion. In this way, by sandwiching the first electrode plate with one folded separator, the number of parts can be reduced compared to sandwiching the first electrode plate with two separators. In addition, by stacking the second electrode plate with the first electrode plate sandwiched between the folded separator, the stacking work can be easily performed. In addition, by arranging the end of the first electrode plate in contact with the separator folded portion of the folded separator, the positioning of the first electrode plate can be easily performed. Furthermore, by arranging the second connection portion of the second electrode plate connected to the second current collector so as to protrude from the separator folded portion, it is possible to suppress contamination (metal powder such as copper) from the second electrode plate from entering the first electrode plate side by the separator folded portion.

[0013] In addition, the second connection portion may be arranged on a side of the main body portion other than the second electrode terminal, and may be connected to the second collector in a state where it is bent in a third direction that intersects the first direction and the second direction.

[0014] According to this, in the electrode body, the second connection part is arranged on a side different from the second electrode terminal of the main body part, and is connected to the second current collector in a state where it is bent in the third direction. Here, in a configuration in which the second connection part is arranged on a side different from the second electrode terminal of the main body part of the electrode body, it is necessary to protrude the second connection part in a direction different from the second electrode terminal (second direction) and connect it to the second current collector, so that the width of the electric storage element in the second direction may become large. For this reason, the second connection part is connected to the second current collector in a state where it is bent in the third direction. This makes it possible to reduce the width of the electric storage element in the second direction, and to achieve space saving. In addition, by bending the second connection part in the third direction, the second connection part can cover the second direction side of the main body part of the electrode body, and therefore it is possible to suppress the intrusion of contamination into the electrode body.

[0015] At least one of the first connection portion and the second connection portion may be a tab protruding from a portion of the main body portion.

[0016] If the first connection part and the second connection part of the electrode body protrude in different directions, problems such as difficulty in connecting the connection parts (first connection part and second connection part) to the electrode terminals (first electrode terminal and second electrode terminal) via the current collectors (first current collector and second current collector) may occur. For this reason, at least one of the first connection part and the second connection part is made into a tab. The tab allows the length of protrusion and the position of protrusion from the main body part of the electrode body to be flexibly set, and can also be easily bent, allowing for flexible connection work with the current collectors. This makes it possible to suppress problems caused by the first connection part and the second connection part of the electrode body protruding in different directions.

[0017] The energy storage element further comprises an electrode body in which positive and negative electrode plates are stacked, a first current collector connected to a first electrode plate of one polarity among the positive and negative electrode plates, and a second current collector connected to a second electrode plate of the other polarity, the electrode body having a main body portion, a first connection portion which is a connection portion between the first electrode plate and the first current collector and protrudes from the main body portion in a first direction, and a second connection portion which is a connection portion between the second electrode plate and the second current collector and protrudes from the main body portion in a second direction intersecting the first direction, and at least one of the first connection portion and the second connection portion may be a tab protruding from a portion of the main body portion.

[0018] According to this, in the energy storage element, the electrode body has a first connection part with the first current collector of the first electrode plate protruding in a first direction, and a second connection part with the second current collector of the second electrode plate protruding in a second direction, and at least one of the first connection part and the second connection part is a tab. In this way, the first connection part of the first electrode plate of the electrode body protrudes in the first direction to connect with the first current collector, and the second connection part of the second electrode plate protrudes in the second direction to connect with the second current collector. As a result, since the current collectors are arranged in both the first direction and the second direction of the electrode body, it is possible to improve protection in both the first direction and the second direction of the electrode body. Therefore, even when an impact is applied from the outside to the electrode body in both the first direction and the second direction, damage to the electrode body can be suppressed.

[0019] Furthermore, if the first and second connection parts of the electrode body protrude in different directions, problems such as difficulty in connecting the connection parts (first and second connection parts) to the electrode terminals (first and second electrode terminals) via the current collectors (first and second current collectors) may occur. For this reason, at least one of the first and second connection parts is a tab. The tab allows for flexible setting of the protruding length and protruding position from the main body of the electrode body, and can also be easily bent, allowing for flexible connection work with the current collectors. This makes it possible to suppress problems caused by the first and second connection parts of the electrode body protruding in different directions.

[0020] The present invention can be realized not only as such an energy storage element, but also as an electrode body, a combination of an electrode body and an electrode terminal (a first electrode terminal and a second electrode terminal), or a combination of an electrode body and a current collector (a first current collector and a second current collector). Effect of the Invention

[0021] According to the present invention, it is possible to provide an energy storage element capable of suppressing damage to an electrode body. [Brief description of the drawings]

[0022] [Figure 1] 1 is a perspective view showing the appearance of an energy storage element according to an embodiment; [Diagram 2] FIG. 2 is an exploded perspective view showing each component of the energy storage element according to the embodiment. [Diagram 3] 2 is an exploded perspective view showing a first electrode plate, a separator, and a second electrode plate of an electrode assembly according to an embodiment. FIG. [Figure 4] FIG. 2 is a front view showing the configuration of a first electrode plate, a separator, and a second electrode plate according to the embodiment. [Diagram 5] 4 is a front view showing a step of placing a first electrode plate on a separator in a manufacturing method of an electrode assembly according to an embodiment. FIG. [Figure 6] 1 is a front view showing a step of arranging a second electrode plate on a first electrode plate and a separator in a manufacturing method of an electrode assembly according to an embodiment. FIG. [Figure 7] 4 is a cross-sectional view showing a step of joining a separator and a second electrode plate in a manufacturing method of an electrode assembly according to an embodiment. FIG. [Figure 8] 5A to 5C are cross-sectional views showing a step of joining an electrode assembly and a second current collector according to an embodiment. [Figure 9] 10A and 10B are a front view and a cross-sectional view showing the configuration of a first electrode plate and a separator according to a modified example of the embodiment, and a process of arranging the first electrode plate on the separator. [Figure 10] FIG. 11 is a front view showing a state in which a second electrode plate is placed on top of a first electrode plate and a separator according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, with reference to the drawings, a description will be given of an energy storage element according to an embodiment (including modified examples) of the present invention. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, the arrangement and connection forms of the components, manufacturing processes, the order of the manufacturing processes, and the like shown in the following embodiments are merely examples and are not intended to limit the present invention. Also, the dimensions, etc., are not strictly illustrated in each drawing.

[0024] In the following description and drawings, the direction in which the first electrode terminal and the second electrode terminal (positive electrode terminal and negative electrode terminal) are arranged, the direction in which the first current collector and the second current collector (positive electrode collector and negative electrode collector) are arranged, or the direction in which the short side surfaces of the container face each other is defined as the X-axis direction. The direction in which the long side surfaces of the container face each other, the thickness direction of the container, the stacking direction of the first electrode plate and the second electrode plate (positive electrode plate and negative electrode plate) of the electrode body, or the stacking direction of these electrode plates and the separator is defined as the Y-axis direction. The direction in which the first electrode terminal and the second electrode terminal and the electrode body are arranged, the stacking direction of the container body and the lid body, or the up-down direction is defined as the Z-axis direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that intersect each other (orthogonal in this embodiment). Note that, depending on the mode of use, it is possible that the Z-axis direction is not the up-down direction, but for convenience of explanation, the following description will be given assuming that the Z-axis direction is the up-down direction.

[0025] In the following description, for example, the positive X-axis direction indicates the direction of the X-axis arrow, and the negative X-axis direction indicates the opposite direction to the positive X-axis direction. The same applies to the Y-axis direction and the Z-axis direction. In the following, the Z-axis direction may be referred to as the first direction, the X-axis direction may be referred to as the second direction, and the Y-axis direction may be referred to as the third direction. Furthermore, expressions indicating relative directions or attitudes, such as parallel and perpendicular, may be used, but these expressions may not strictly refer to the directions or attitudes. For example, two directions being perpendicular to each other not only means that the two directions are completely perpendicular to each other, but also means that the two directions are substantially perpendicular to each other, that is, that there is a difference of, for example, about several percent.

[0026] (Embodiment) [1 General Description of Energy Storage Element 10] First, an overall description of an energy storage device 10 according to the present embodiment will be given. Fig. 1 is a perspective view showing the external appearance of an energy storage device 10 according to the present embodiment. Fig. 2 is an exploded perspective view showing each component of the energy storage device 10 according to the present embodiment.

[0027] The energy storage element 10 is a secondary battery capable of charging and discharging electricity, specifically a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. For example, the energy storage element 10 is used for power storage or power supply. Specifically, the energy storage element 10 is used as a battery for driving or starting an engine of a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, or a railway vehicle for an electric railway. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a gasoline-powered vehicle. Examples of the railway vehicle for the electric railway include a train, a monorail, and a linear motor car. The energy storage element 10 can also be used as a stationary battery for home use or for a power generator.

[0028] The energy storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 10 may not be a secondary battery, but may be a primary battery that allows the user to use stored electricity without charging it. In this embodiment, the energy storage element 10 is illustrated as having a flattened rectangular parallelepiped (corneral) shape, but the shape of the energy storage element 10 is not limited to a rectangular parallelepiped shape, and may be a polygonal prism shape, an oval cylinder shape, or the like other than a rectangular parallelepiped shape. The energy storage element 10 may be a laminate type energy storage element.

[0029] As shown in FIG. 1, the energy storage element 10 includes a container 100, a first electrode terminal 200, and a second electrode terminal 300. As shown in FIG. 2, the container 100 contains a first current collector 400, a second current collector 500, and an electrode assembly 600. Between the container 100 (a lid 120 described later) and the first and second electrode terminals 200 and 300, and between the first and second current collectors 400 and 500, gaskets and the like are arranged to enhance electrical insulation and airtightness, and an electrolyte (non-aqueous electrolyte) is sealed inside the container 100, but these are not shown. There is no particular limit to the type of electrolyte as long as it does not impair the performance of the energy storage element 10, and various electrolytes can be selected. In addition to the above components, a spacer arranged on the side, above, or below the electrode assembly 600, and an insulating film that wraps the electrode assembly 600, etc. may be provided.

[0030] The container 100 is a rectangular parallelepiped (rectangular or box-shaped) case having a container body 110 with an opening and a lid body 120 that closes the opening of the container body 110. With this configuration, the container 100 has a structure in which the inside can be sealed by, for example, welding the container body 110 and the lid body 120 together after the electrode body 600 and the like are accommodated inside the container body 110. The container 100 (the container body 110 and the lid body 120) is formed of a plate-like member that is relatively thick and rigid. The material of the container 100 (the container body 110 and the lid body 120) is not particularly limited, and can be, for example, a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, but resin can also be used.

[0031] The container body 110 is a rectangular cylindrical member having a bottom that constitutes the main body of the container 100, and has an opening formed on the positive Z-axis direction side. The lid body 120 is a rectangular plate-like member that constitutes the lid of the container 100, and is disposed extending in the X-axis direction on the positive Z-axis direction side of the container body 110. The lid body 120 is provided with a gas exhaust valve 121 that exhausts gas from inside the container 100 when the internal pressure of the container 100 increases. The container 100 may be provided with a liquid injection section for injecting an electrolyte into the container 100.

[0032] The electrode body 600 is an electricity storage element (power generation element) that includes a plurality of first electrodes (first electrodes 630 described below), a plurality of second electrodes (second electrodes 650 described below), and a plurality of separators (separators 640 described below) and can store electricity. The first electrodes 630 are electrodes of one polarity of a positive electrode plate and a negative electrode plate, and the second electrodes 650 are electrodes of the other polarity. In this embodiment, the first electrodes 630 are positive electrodes, and the second electrodes 650 are negative electrodes.

[0033] Specifically, the electrode body 600 is formed by stacking a plurality of first electrode plates 630 (positive electrode plates), a plurality of second electrode plates 650 (negative electrode plates), and a plurality of separators 640 (see FIG. 3). As a result, in the electrode body 600, the parts of the first electrode plates 630 that protrude in the positive direction of the Z axis (first connection part 631a described later) are stacked to form the convergence part 610, and the parts of the second electrode plates 650 that protrude in the positive direction of the X axis (second connection part 651a described later) are stacked to form the convergence part 620. That is, the electrode body 600 has an electrode body main body part 601 that constitutes the main body of the electrode body 600, a positive electrode side convergence part 610 that protrudes from the end of the electrode body main body part 601 in the positive direction of the Z axis, and a negative electrode side convergence part 620 that protrudes from the end of the electrode body main body part 601 in the positive direction of the X axis. A detailed description of the configuration of the electrode body 600 will be given later.

[0034] The first electrode terminal 200 and the second electrode terminal 300 are terminal members electrically connected to the electrode body 600 via the first current collector 400 and the second current collector 500. In this embodiment, the first electrode terminal 200 is a positive electrode terminal, and the second electrode terminal 300 is a negative electrode terminal. That is, the first electrode terminal 200 and the second electrode terminal 300 are metal members for leading out electricity stored in the electrode body 600 to the external space of the energy storage element 10 and for introducing electricity into the internal space of the energy storage element 10 to store electricity in the electrode body 600. The first electrode terminal 200 and the second electrode terminal 300 are formed of a conductive member such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy. The first electrode terminal 200 and the second electrode terminal 300 are connected (joined) to the first current collector 400 and the second current collector 500 by crimping or the like, and are attached to the cover body 120 via a gasket or the like to enhance electrical insulation and airtightness.

[0035] 2, the first electrode terminal 200 is fixed to the cover 120 together with the first current collector 400 via a gasket or the like by inserting the shaft portion 210 into the through hole 122 of the cover 120 and the through hole 410 of the first current collector 400 and crimping the shaft portion 210. Similarly, the second electrode terminal 300 is fixed to the cover 120 together with the second current collector 500 via a gasket or the like by inserting the shaft portion 310 into the through hole 123 of the cover 120 and the through hole 511 of the second current collector 500 and crimping the shaft portion 210.

[0036] As a result, the first electrode terminal 200 and the second electrode terminal 300 are disposed so as to protrude from the cover body 120 in the positive direction of the Z axis. That is, the first electrode terminal 200 and the second electrode terminal 300 are disposed on the same side (the positive direction of the Z axis) of the electrode body 600. Note that the method for connecting (joining) the first electrode terminal 200 and the second electrode terminal 300 to the first current collector 400 and the second current collector 500 is not limited to crimping, and may be welding such as ultrasonic welding, laser welding, or resistance welding, or mechanical joining other than crimping such as rivet joining or screw fastening.

[0037] The first current collector 400 and the second current collector 500 are disposed on both sides of the electrode body 600 in the X-axis direction, and are current collecting members having conductivity and rigidity, which are connected (joined) to the electrode body 600 and the first electrode terminal 200 and the second electrode terminal 300. The first current collector 400 and the second current collector 500 are members having a relatively large thickness and rigidity, unlike lead plates which are thin and easily bent. In this embodiment, the first current collector 400 is a positive electrode current collector, and the second current collector 500 is a negative electrode current collector. Specifically, the first current collector 400 is connected to the convergence portion 610 (the first connection portion 631a of the first electrode plate 630) of the electrode body 600 and the first electrode terminal 200, and the second current collector 500 is connected to the convergence portion 620 (the second connection portion 651a of the second electrode plate 650) of the electrode body 600 and the second electrode terminal 300. As a result, the first current collector 400 and the second current collector 500 electrically connect the electrode body 600 to the first electrode terminal 200 and the second electrode terminal 300. The method for connecting (joining) the first current collector 400 and the second current collector 500 to the focusing portions 610 and 620 may be any type of welding such as ultrasonic welding, laser welding, resistance welding, or the like, or may be mechanical joining such as crimping or screw fastening.

[0038] Specifically, the first current collector 400 is a plate-like member disposed along the lid 120 between the lid 120 and the electrode body 600, and the second current collector 500 is a plate-like member disposed in a bent state along the side wall and the lid 120 from the side wall of the container body 110 to the lid 120. The first current collector 400 and the second current collector 500 are fixedly connected (joined) to the lid 120. The materials of the first current collector 400 and the second current collector 500 are not particularly limited, but for example, the first current collector 400 (positive electrode current collector) is formed of aluminum or an aluminum alloy, and the second current collector 500 (negative electrode current collector) is formed of copper or a copper alloy.

[0039] As shown in FIG. 2, the second current collector 500 has a terminal connection part 510 and an electrode connection part 520 extending from an end part of the terminal connection part 510 in the X-axis direction toward the negative direction of the Z-axis. The terminal connection part 510 is a base part of the second current collector 500 that is connected (joined) to the second electrode terminal 300. That is, the terminal connection part 510 is a rectangular and flat part arranged on the second electrode terminal 300 side (upper side, Z-axis positive direction) of the second current collector 500, and is electrically and mechanically connected to the second electrode terminal 300 as described above. The electrode connection part 520 is a leg part of the second current collector 500 that is connected (joined) to the electrode body 600. That is, the electrode connection part 520 is a part arranged on the electrode body 600 side (lower side, Z-axis negative direction) of the second current collector 500, and is electrically and mechanically connected to the electrode body 600. Specifically, the electrode connection portion 520 is an elongated, flat portion extending in the Z-axis direction, and is joined to the converging portion 620 of the electrode body 600.

[0040] [2. Description of the configuration of the electrode body 600] [2.1 Description of the schematic configuration of the electrode assembly 600] Next, the configuration of the electrode body 600 will be described in detail. First, a schematic configuration of the electrode body 600 will be described. FIG. 3 is an exploded perspective view showing the first electrode plate 630, the separator 640, and the second electrode plate 650 of the electrode body 600 according to the present embodiment. FIG. 4 is a front view showing the configuration of the first electrode plate 630, the separator 640, and the second electrode plate 650 according to the present embodiment. Specifically, FIG. 4(a) is a front view showing the configuration of the first electrode plate 630, FIG. 4(b) is a front view showing the configuration of the separator 640, and FIG. 4(c) is a front view showing the configuration of the second electrode plate 650.

[0041] 3, the electrode body 600 is formed by alternately stacking a first electrode plate 630 (positive electrode plate), a separator 640, and a second electrode plate 650 (negative electrode plate). In other words, the electrode body 600 is formed by repeatedly stacking the first electrode plate 630, the separator 640, and the second electrode plate 650 alternately so that the second electrode plate 650 is arranged at both ends in the Y-axis direction and the first electrode plate 630 is arranged inside the second electrode plate 650. In order to ensure electrical insulation between the container 100 and the electrode body 600, an insulating member such as a separator or an insulating sheet may be arranged on the outside of the second electrode plate 650 at both ends in the Y-axis direction (both side surfaces in the Y-axis direction of the electrode body 600).

[0042] Specifically, the separator 640 is formed by folding back one separator, and the separator 640 sandwiches the first electrode plate 630 and is laminated with the second electrode plate 650. The separator 640 formed by folding back one separator is an example of a folded separator. In other words, it can be said that the multiple separators 640 include folded separators formed by folding back one separator. In this embodiment, all the separators 640 are folded separators. In this way, the separator 640 (folded separator) sandwiches the first electrode plate 630 and is disposed between the two second electrode plates 650.

[0043] As described above, by stacking the first electrode plate 630, the separator 640, and the second electrode plate 650, a positive electrode side convergence portion 610 is formed in the electrode body 600 by stacking the portions of the first electrode plates 630 protruding in the positive direction of the Z axis, and a negative electrode side convergence portion 620 is formed in the electrode body 600 by stacking the portions of the second electrode plates 650 protruding in the positive direction of the X axis, as shown in Fig. 2. The configurations of the first electrode plate 630 (positive electrode plate), the separator 640 (folded separator), and the second electrode plate 650 (negative electrode plate) will be specifically described below.

[0044] As shown in FIG. 4(a), the first electrode plate 630 (positive electrode plate) has a positive electrode substrate 631 and a positive electrode composite layer 632. The positive electrode substrate 631 is a conductive current collector foil made of aluminum or an aluminum alloy, which is substantially rectangular and flat and elongated in the X-axis direction. The positive electrode substrate 631 has a first connection portion 631a which is a rectangular tab protruding in the Z-axis positive direction from the end of the edge in the Z-axis positive direction in the X-axis negative direction. The first connection portion 631a is a connection portion of the first electrode plate 630 with the first current collector 400. Note that, as the positive electrode substrate 631, any known material may be used as long as it is stable against oxidation-reduction reactions during charging and discharging, such as nickel, iron, stainless steel, titanium, baked carbon, conductive polymer, conductive glass, and Al-Cd alloy.

[0045] The positive electrode mixture layer 632 is a positive electrode-side mixture layer provided on the surface (both sides) of the positive electrode substrate 631, and is disposed over the entire surface (from one edge to the other edge in the Z-axis direction and from one edge to the other edge in the X-axis direction) of the positive electrode substrate 631 other than the first connection portion 631a. That is, the first connection portion 631a is a portion exposed from the positive electrode mixture layer 632. In other words, the first connection portion 631a is a mixture layer non-formation portion of the positive electrode substrate 631 where the positive electrode mixture layer 632 is not formed. Note that an edge coat layer (insulating coat layer) containing particles such as inorganic particles and a binder may be provided along the edge of the positive electrode mixture layer 632 in the Z-axis positive direction (at the boundary portion between the first connection portion 631a and the positive electrode mixture layer 632).

[0046] The positive electrode mixture layer 632 contains a positive electrode active material, a conductive additive, and a binder. As the positive electrode active material used in the positive electrode mixture layer 632, any known material can be used as long as it is a positive electrode active material capable of absorbing and releasing lithium ions. For example, LiMPO 4 , LiMSiO 4 , LiMBO 3 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), polyanion compounds such as lithium titanate, LiMn 2 O 4 yaLiMn 1.5 Ni 0.5O 4 Spinel-type lithium manganese oxides such as LiMO 2 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.) or the like can be used. The type of conductive assistant used in the positive electrode mixture layer 632 is not particularly limited, and may be a metal or a nonmetal as long as it is a material that is stable to oxidation-reduction reactions during charging and discharging. The type of binder used in the positive electrode mixture layer 632 is not particularly limited as long as it is a material that is stable to the solvent and electrolyte used in the electrode production and is stable to oxidation-reduction reactions during charging and discharging. An insulating coating layer containing particles such as inorganic particles and a binder may be provided on the positive electrode mixture layer 632.

[0047] The separator 640 is a rectangular, flat, microporous sheet made of, for example, resin, elongated in the X-axis direction. Any known material can be used as the material of the separator 640 as long as it does not impair the performance of the energy storage element 10. For example, the separator 640 can be a woven fabric or nonwoven fabric insoluble in an organic solvent, or a synthetic resin microporous film made of a polyolefin resin such as polyethylene. The separator 640 may be a laminate of a plurality of microporous films having different materials, weight average molecular weights, or porosities, a microporous film containing appropriate amounts of additives such as various plasticizers, antioxidants, and flame retardants, or a microporous film coated with an inorganic oxide such as alumina or silica mixed with a binder on one or both sides of the microporous film. In particular, as the separator 640, a synthetic resin microporous film can be preferably used, and among them, polyolefin-based microporous films such as polyethylene and polypropylene microporous films, polyethylene and polypropylene microporous films composited with aramid or polyimide, or microporous films composited with these are preferably used in terms of thickness, film strength, film resistance, etc.

[0048] As shown in FIG. 4B, the separator 640 has two separator parts 641 and 642 and a separator folded part 643. The separator parts 641 and 642 are two rectangular and flat parts that are elongated in the X-axis direction and sandwich the first electrode plate 630, and are arranged side by side in the X-axis direction. The separator folded part 643 is arranged between the two separator parts 641 and 642 (at the boundary part) and is an elongated part in the Z-axis direction that connects the ends of the two separator parts 641 and 642. In other words, the separator part 642 is folded back in the X-axis direction at the separator folded part 643 with respect to the separator part 641, so that the separator part 641 and the separator part 642 sandwich the first electrode plate 630.

[0049] In this embodiment, separator portion 641 and separator portion 642 have the same shape and size. Separator portion 641 and separator portion 642 are formed so that their lengths in the X-axis direction are greater than the length of first electrode plate 630 in the X-axis direction. Separator portion 641 and separator portion 642 are formed so that their lengths in the Z-axis direction are greater than the length of a portion of first electrode plate 630 other than first connection portion 631a in the Z-axis direction.

[0050] As shown in FIG. 4(c), the second electrode plate 650 (negative electrode plate) has a negative electrode substrate 651 and a negative electrode composite layer 652. The negative electrode substrate 651 is a rectangular, flat, conductive current collector foil made of copper or a copper alloy, and is elongated in the X-axis direction. The negative electrode substrate 651 has a second connection portion 651a which is a rectangular tab protruding in the X-axis positive direction from the end of the edge in the Z-axis positive direction of the edge in the X-axis positive direction. The second connection portion 651a is a connection portion of the second electrode plate 650 with the second current collector 500 (the electrode connection portion 520 of the second current collector 500). Note that the negative electrode substrate 651 can be made of the same material as the positive electrode substrate 631, such as nickel, as long as the material is stable against oxidation-reduction reactions during charging and discharging.

[0051] The negative electrode composite material layer 652 is a composite material layer on the negative electrode side provided on the surfaces (both surfaces) of the negative electrode substrate 651, and is disposed over the entire surface (from one edge to the other edge in the Z-axis direction and from one edge to the other edge in the X-axis direction) of the negative electrode substrate 651 except for the second connection portion 651a. That is, the second connection portion 651a is a portion exposed from the negative electrode composite material layer 652. In other words, the second connection portion 651a is a composite material layer non-formation portion of the negative electrode substrate 651 where the negative electrode composite material layer 652 is not formed.

[0052] In the present embodiment, negative electrode composite layer 652 is formed so that its length in the X-axis direction is greater than the lengths in the X-axis direction of positive electrode composite layer 632, separator portion 641, and separator portion 642. Furthermore, second electrode plate 650 is formed so that its length in the Z-axis direction is greater than the length in the Z-axis direction of positive electrode composite layer 632 and less than the length in the Z-axis direction of separator 640.

[0053] The negative electrode mixture layer 652 contains a negative electrode active material, a conductive assistant, and a binder. As the negative electrode active material used in the negative electrode mixture layer 652, any known material can be used as long as it is a negative electrode active material capable of absorbing and releasing lithium ions. For example, the negative electrode active material may be lithium metal, lithium alloys (lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, Wood's alloy, and other lithium metal-containing alloys), as well as alloys capable of absorbing and releasing 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, commonly called conversion anodes, Co 3 O 4 or Fe 2Examples of the conductive additive and binder include compounds of a transition metal such as P and an element of Groups 14 to 16. The conductive additive and binder used in the negative electrode mixture layer 652 are similar to the conductive additive and binder used in the positive electrode mixture layer 632, and therefore detailed description thereof will be omitted. Note that an insulating coating layer containing particles such as inorganic particles and a binder may be provided on the negative electrode mixture layer 652.

[0054] [2.2 Manufacturing method and detailed configuration of electrode body 600] Next, a more detailed configuration of the electrode assembly 600 will be described while explaining a manufacturing method of the electrode assembly 600. Fig. 5 is a front view showing a step of arranging the first electrode plate 630 on the separator 640 in the manufacturing method of the electrode assembly 600 according to the present embodiment. Specifically, Fig. 5(a) is a front view showing a state in which the first electrode plate 630 is arranged on the separator 640, and Fig. 5(b) is a front view showing a state in which the separator 640 is folded back.

[0055] Fig. 6 is a front view showing a step of arranging a second electrode plate 650 on a first electrode plate 630 and a separator 640 in a manufacturing method of an electrode body 600 according to the present embodiment. Specifically, Fig. 6(a) is a front view showing a state in which the second electrode plate 650 is arranged on the first electrode plate 630 and the separator 640, and Fig. 6(b) is a perspective view showing a state in which the first electrode plate 630, the separator 640, and the second electrode plate 650 are laminated to form the electrode body 600.

[0056] Fig. 7 is a cross-sectional view showing a step of joining the separator 640 and the second electrode plate 650 in the manufacturing method of the electrode assembly 600 according to the present embodiment. Specifically, Fig. 7 is a cross-sectional view showing a configuration in which the end of the electrode assembly 600 in the negative Z-axis direction shown in Fig. 6(b) is cut along a plane parallel to the YZ plane. Fig. 8 is a cross-sectional view showing a step of joining the electrode assembly 600 according to the present embodiment and the second current collector 500. Specifically, Fig. 8 is a cross-sectional view showing a configuration in which the joined state of the electrode assembly 600 and the second current collector 500 is cut along a plane parallel to the XY plane.

[0057] First, as shown in FIG. 5(a), the first electrode plate 630 is placed on the separator portion 641 of the separator 640. Specifically, the first electrode plate 630 is disposed with respect to the separator portion 641 so that the edge of the first electrode plate 630 in the positive X-axis direction overlaps with the edge of the separator portion 641 in the positive X-axis direction (i.e., the separator folded-back portion 643). As a result, the edge of the separator portion 641 in the negative X-axis direction protrudes from the edge of the first electrode plate 630 in the negative X-axis direction. The first connection portion 631a of the first electrode plate 630 protrudes from the edge of the separator portion 641 in the positive Z-axis direction. The portions of the first electrode plate 630 other than the first connection portion 631a are disposed so that the separator portion 641 protrudes in the positive Z-axis direction and the negative Z-axis direction.

[0058] Then, as shown in FIG. 5B, the separator portion 642 of the separator 640 is folded back at the separator folded back portion 643 with respect to the separator portion 641 and placed on the first electrode plate 630. As a result, the separator portion 642 covers the positive electrode composite layer 632 of the first electrode plate 630. That is, the first connection portion 631a is in a state of protruding from the separator 640 in the Z-axis positive direction. The separator folded back portion 643 is disposed on the edge of the separator 640 in the X-axis positive direction. When the first electrode plate 630 is disposed on the separator portion 641 or when the separator portion 642 is disposed on the first electrode plate 630, the first electrode plate 630 may be joined (bonded) to the separator 640 by an adhesive or the like.

[0059] 6(a), second electrode plate 650 is placed on separator 640 sandwiching first electrode plate 630. Specifically, second electrode plate 650 is placed on separator 640 such that negative electrode mixture layer 652 of second electrode plate 650 is positioned to cover positive electrode mixture layer 632 of first electrode plate 630.

[0060] That is, the edge of the negative electrode mixture layer 652 in the X-axis negative direction is disposed further in the X-axis negative direction than the edge of the positive electrode mixture layer 632 in the X-axis negative direction. In this embodiment, the edge of the negative electrode mixture layer 652 in the X-axis negative direction is disposed at a position overlapping the edge of the separator 640 in the X-axis negative direction. Note that the edge of the negative electrode mixture layer 652 in the X-axis negative direction may be disposed further in the X-axis positive direction than the edge of the separator 640 in the X-axis negative direction, or may be disposed in the X-axis negative direction, as long as it is disposed further in the X-axis negative direction than the edge of the positive electrode mixture layer 632 in the X-axis negative direction.

[0061] The edge of the negative electrode mixture layer 652 in the positive X-axis direction is disposed further in the positive X-axis direction than the edge of the positive X-axis direction of the positive electrode mixture layer 632. In the present embodiment, the edge of the negative electrode mixture layer 652 in the positive X-axis direction is disposed further in the positive X-axis direction than the separator folded-back portion 643. This results in a state in which the second connection portion 651a protrudes in the positive X-axis direction from the separator folded-back portion 643. Note that the edge of the negative electrode mixture layer 652 in the positive X-axis direction may be disposed at a position overlapping the separator folded-back portion 643, or may be disposed in the negative X-axis direction than the separator folded-back portion 643, as long as it is disposed further in the positive X-axis direction than the edge of the positive electrode mixture layer 632 in the positive X-axis direction.

[0062] The positive edge of negative electrode mixture layer 652 on the Z axis is positioned further in the positive direction than the positive edge of positive electrode mixture layer 632 on the Z axis, and further in the negative direction than the positive edge of separator 640 on the Z axis.

[0063] The edge of the negative electrode mixture layer 652 in the Z-axis negative direction is disposed further in the Z-axis negative direction than the edge of the positive electrode mixture layer 632 in the Z-axis negative direction. In this embodiment, the edge of the negative electrode mixture layer 652 in the Z-axis negative direction is disposed at a position overlapping with the edge of the separator 640 in the Z-axis negative direction. Note that the edge of the negative electrode mixture layer 652 in the Z-axis negative direction may be disposed further in the Z-axis positive direction than the edge of the separator 640 in the Z-axis negative direction, or may be disposed in the Z-axis negative direction, as long as it is disposed further in the Z-axis negative direction than the edge of the positive electrode mixture layer 632 in the Z-axis negative direction.

[0064] In this manner, the separator 640 and the second electrode plate 650 sandwiching the first electrode plate 630 are stacked to form an electrode body 600 having a substantially rectangular parallelepiped shape, as shown in Fig. 6(b). That is, the first connection portion 631a of the first electrode plate 630 is stacked to form the positive electrode side convergence portion 610, and the second connection portion 651a of the second electrode plate 650 is stacked to form the negative electrode side convergence portion 620.

[0065] The first connection portion 631a is a portion that protrudes in the Z-axis direction (first direction) from the electrode body main body 601, and specifically, is a tab that protrudes in the Z-axis positive direction from a part of the electrode body main body 601 (the end of the electrode body main body 601 in the Z-axis positive direction, in the X-axis negative direction). The second connection portion 651a is a portion that protrudes in the X-axis direction (second direction intersecting with the first direction) from the electrode body main body 601, and specifically, is a tab that protrudes in the X-axis positive direction from a part of the electrode body main body 601 (the end of the electrode body main body 601 in the X-axis positive direction, in the Z-axis positive direction, in the X-axis positive direction).

[0066] The converging portion 610 is a tab bundle protruding in the Z-axis positive direction from the end of the Z-axis positive edge of the electrode body main body 601 in the X-axis negative direction, and the converging portion 620 is a tab bundle protruding in the X-axis positive direction from the end of the Z-axis positive edge of the electrode body main body 601 in the X-axis positive direction. The electrode body main body 601 is a portion constituting the main body of the electrode body 600, and specifically, a portion (a portion where a composite layer is formed) other than the converging portions 610 and 620 (other than the first connection portion 631a and the second connection portion 651a) of the electrode body 600. In other words, the electrode body main body 601 is a flat rectangular parallelepiped portion formed by stacking a portion of the positive electrode substrate 631 other than the first connection portion 631a, the positive electrode composite layer 632, a portion of the negative electrode substrate 651 other than the second connection portion 651a, the negative electrode composite layer 652, and the separator 640.

[0067] With this configuration, the first connection portion 631a is a portion that protrudes from the end of the electrode body main body 601 on the opposite side to the second connection portion 651a. In other words, the first connection portion 631a is a portion that protrudes from the end (end in the negative direction of the X-axis) on the opposite side to the second connection portion 651a at the edge of the electrode body main body 601 in the positive direction of the Z-axis. In contrast, the second connection portion 651a is a portion that protrudes from the end (end in the positive direction of the Z-axis) on the same side as the first connection portion 631a at the edge of the electrode body main body 601 in the positive direction of the X-axis.

[0068] Further, the second connection portion 651a is a portion disposed on a different side of the electrode body main body portion 601 from the second electrode terminal 300. That is, the second electrode terminal 300 is disposed in the Z-axis positive direction of the electrode body main body portion 601, and the second connection portion 651a is disposed in the X-axis positive direction of the electrode body main body portion 601, so that the second connection portion 651a is disposed on a different side of the electrode body main body portion 601 from the second electrode terminal 300. In contrast, the first connection portion 631a is disposed on the same side as the first electrode terminal 200 of the electrode body main body portion 601, that is, both are disposed in the Z-axis positive direction of the electrode body main body portion 601.

[0069] Next, in a state in which the electrode body 600 shown in (b) of Fig. 6 is formed, the separator 640 and the second electrode plate 650 are joined. Specifically, ends of the two separator portions 641 and 642 of the separator 640 are joined to ends of the two second electrode plates 650 sandwiching the separator 640. That is, as shown in Fig. 7, an end 641a of the separator portion 641, an end 642a of the separator portion 642, an end 651b of the negative electrode substrate 651, and an end 652a of the negative electrode composite layer 652 are joined by a joining member 660 such as an adhesive (glue, etc.). Although these ends 641a, 642a, 651b and 652a are ends of the separator 640 and the second electrode plate 650 in the negative Z-axis direction, the ends of the separator 640 and the second electrode plate 650 in the negative X-axis direction are joined in the same manner.

[0070] For example, the bonding member 660 is applied to a plate-shaped member and the electrode body 600 is pressed against the plate-shaped member, so that the bonding member 660 is applied to both ends in the Z-axis direction of the electrode body 600. As a result, the ends of the separator 640 and the second electrode plate 650 of the electrode body 600 in the negative Z-axis direction are bonded, and the ends of the separator 640 and the second electrode plate 650 in the negative X-axis direction are bonded. Here, the binder contained in the adhesive (glue or the like) used in the bonding member 660 is preferably a different type from the binder contained in the negative electrode mixture layer 652 of the second electrode plate 650.

[0071] Note that a configuration may be used in which only either the ends of the separator 640 and the second electrode plate 650 in the negative Z-axis direction or the ends in the negative X-axis direction are joined. The method for joining the separator 640 and the second electrode plate 650 is not limited to applying an adhesive such as a paste, and any adhesive may be used, or instead of an adhesive, an adhesive tape may be attached, or mechanical joining such as welding or crimping may be used.

[0072] The electrode body 600 manufactured in this manner is joined to the first current collector 400 and the second current collector 500. That is, the converging portion 610 on which the first connection portion 631a of the first electrode plate 630 is laminated is joined to the first current collector 400, and the converging portion 620 on which the second connection portion 651a of the second electrode plate 650 is laminated is joined to the second current collector 500.

[0073] 8, the converging portion 620 (second connection portion 651a) is disposed outside the electrode connection portion 520 of the second current collector 500 (the positive X-axis direction side, the opposite side to the electrode body main body portion 601) and is joined to the electrode connection portion 520. In other words, the converging portion 620 is bent in the Y-axis direction so as to wrap around to the outside of the electrode connection portion 520 and is joined to the electrode connection portion 520. In this way, the second connection portion 651a is connected to the second current collector 500 in a state where it is bent in the Y-axis direction (a third direction intersecting the first and second directions).

[0074] Specifically, a backing plate 700 is disposed on the outside of the converging portion 620, and the electrode connection portion 520 and the backing plate 700 are joined together in a state in which the converging portion 620 is sandwiched between the electrode connection portion 520 and the backing plate 700. The backing plate 700 is a flat metal cover that protects the converging portion 620. The material of the backing plate 700 is not particularly limited as long as it is a material that is stable against oxidation-reduction reactions during charging and discharging, and is formed of, for example, copper or a copper alloy.

[0075] The converging portion 610 (first connection portion 631a) is disposed on the inner side of the first current collector 400 (the Z-axis negative direction side, the electrode body main body portion 601 side) and is joined to the first current collector 400. That is, the converging portion 610 is bent so as to follow the inner surface of the first current collector 400 and is joined to the first current collector 400. Specifically, a backing plate (not shown) similar to the backing plate 700 is disposed on the inner side of the converging portion 610, and the first current collector 400 and the converging portion 610 are joined in a state in which the converging portion 610 is sandwiched between the first current collector 400 and the backing plate. The backing plate is formed of, for example, aluminum or an aluminum alloy.

[0076] [3 Explanation of effects] As described above, according to the energy storage element 10 according to the embodiment of the present invention, the electrode body 600 has the first connection portion 631a protruding in the first direction (Z-axis direction) and the second connection portion 651a protruding in the second direction (X-axis direction), and the first electrode terminal 200 and the second electrode terminal 300 are arranged on the same side of the electrode body 600. In this manner, the first connection portion 631a of the first electrode plate 630 of the electrode body 600 protrudes in the first direction to be connected to the first current collector 400, and the second connection portion 651a of the second electrode plate 650 protrudes in the second direction to be connected to the second current collector 500. As a result, since the current collectors are arranged in both the first direction and the second direction of the electrode body 600, it is possible to improve the protection of the electrode body 600 in both the first direction and the second direction. Therefore, even when an impact is applied from the outside to the electrode body 600 in both the first direction and the second direction, damage to the electrode body 600 can be suppressed.

[0077] In addition, the first connection portion 631a and the second connection portion 651a of the electrode body 600 protrude in different directions. If the first electrode terminal 200 and the second electrode terminal 300 are also arranged in different directions accordingly, problems such as difficulty in connecting the energy storage element 10 to other devices will occur. For this reason, the first electrode terminal 200 and the second electrode terminal 300 are arranged on the same side of the electrode body 600. This makes it possible to simplify the system configuration, such as facilitating the connection between the energy storage element 10 and other devices. In this way, it is possible to suppress problems caused by the first connection portion 631a and the second connection portion 651a of the electrode body 600 protruding in different directions.

[0078] In addition, in the electrode body 600, the first connection part 631a is protruded from the end of the electrode body main body part 601 opposite to the second connection part 651a, so that the first connection part 631a and the second connection part 651a are disposed at positions apart from each other. This makes it possible to reduce the risk of a short circuit occurring due to the first connection part 631a and the second connection part 651a (or the first current collector 400 and the second current collector 500) coming close to each other, even in the event of an abnormal state such as an external impact.

[0079] In addition, the first electrode terminal 200 and the second electrode terminal 300 are arranged on the same side of the electrode body 600, but in order to prevent short circuits, it is preferable that the first electrode terminal 200 and the second electrode terminal 300 are arranged at positions separated to some extent. By arranging the first connection portion 631a and the second connection portion 651a at positions separated from each other, it becomes easier to arrange the first electrode terminal 200 and the second electrode terminal 300 at positions separated from each other. As a result, by making the first connection portion 631a protrude from the end portion of the electrode body main body portion 601 opposite to the second connection portion 651a, it is possible to suppress problems caused by arranging the first electrode terminal 200 and the second electrode terminal 300 on the same side of the electrode body 600.

[0080] In the electrode body 600, the separator 640 (folded separator) has a separator folded portion 643 that connects the ends of the two separator portions 641 and 642 that sandwich the first electrode plate 630, and the second connection portion 651a is disposed protruding from the separator folded portion 643. In this way, by sandwiching the first electrode plate 630 with one separator 640, the number of parts can be reduced compared to sandwiching the first electrode plate 630 with two separators. In addition, by stacking the second electrode plate 650 with the first electrode plate 630 sandwiched between the separator 640, the stacking operation can be easily performed. In addition, by arranging the end of the first electrode plate 630 in contact with the separator folded portion 643 of the separator 640, the positioning of the first electrode plate 630 can also be easily performed. Furthermore, since the second connection portion 651a of the second electrode plate 650 is positioned to protrude from the separator folded portion 643, the separator folded portion 643 can prevent contamination (such as metal powder of copper or the like) from the second electrode plate 650 from penetrating into the first electrode plate 630 side.

[0081] In addition, in the electrode body 600, the second connection portion 651a is disposed on a side of the electrode body main body 601 different from the second electrode terminal 300, and is connected to the second current collector 500 in a state of being bent in the third direction (Y-axis direction). Here, in a configuration in which the second connection portion 651a is disposed on a side of the electrode body main body 601 different from the second electrode terminal 300, it is necessary to connect the second connection portion 651a to the second current collector 500 by protruding in a direction (second direction) different from the second electrode terminal 300. For this reason, there is a risk that the width of the energy storage element 10 in the second direction will be large, so the second connection portion 651a is bent in the third direction and connected to the second current collector 500. This makes it possible to reduce the width of the energy storage element 10 in the second direction, thereby enabling space saving. In addition, by bending the second connection portion 651a in the third direction, the second connection portion 651a can cover the second direction side of the electrode body main body 601, and therefore it is possible to suppress the intrusion of contamination into the electrode body 600.

[0082] In addition, when the two connection parts, the first connection part 631a and the second connection part 651a, protrude in different directions, there is a risk of problems such as difficulty in connecting the connection parts to the electrode terminals (the first electrode terminal 200 and the second electrode terminal 300) via the current collectors (the first current collector 400 and the second current collector 500). For this reason, at least one of the first connection part 631a and the second connection part 651a is a tab. The tab can flexibly set the protruding length and protruding position from the electrode body main body part 601, and can also be easily bent, allowing for flexible connection work with the current collectors. This makes it possible to suppress problems caused by the first connection part 631a and the second connection part 651a protruding in different directions.

[0083] In addition, since the second connection part 651a is disposed at the end of the electrode body main body part 601 in the positive direction of the Z axis, a space is generated between the electrode body main body part 601 and the container body 110 at the end side in the positive direction of the Z axis. As a result, a space is provided in the container 100, which can improve the pouring property when pouring the electrolyte into the container 100, and can also be used as a space for storing the electrolyte.

[0084] [4 Explanation of Modifications] Next, a modified example of the above embodiment will be described. FIG. 9 is a front view and a cross-sectional view showing the configuration of the first electrode plate 630 and the separator 640 according to the modified example of the present embodiment, and a process of arranging the first electrode plate 630 on the separator 640. Specifically, FIG. 9(a) is a view corresponding to FIG. 5(a), FIG. 9(b) is a view corresponding to FIG. 5(b), and FIG. 9(c) is a cross-sectional view showing the configuration of joining the separator parts 641 and 642 of the separator 640. FIG. 10 is a front view showing a state in which the second electrode plate 650 is arranged so as to overlap the first electrode plate 630 and the separator 640 according to the modified example of the present embodiment. FIG. 10 is a view corresponding to FIG. 6(a).

[0085] 9(a), the two separator portions 641 and 642 of the separator 640 in this modification are two rectangular, flat portions that are elongated in the X-axis direction and sandwich the first electrode plate 630, as in the above embodiment, but are arranged side by side in the Z-axis direction. Thus, the separator 640 in this modification has a separator folded-back portion 643a that is elongated in the X-axis direction and that is arranged between the two separator portions 641 and 642 (at the boundary portion) and connects the ends of the two separator portions 641 and 642.

[0086] 9(b), separator portion 642 is folded back in the Z-axis direction relative to separator portion 641 at separator folded back portion 643a, whereby first electrode plate 630 is sandwiched between separator portion 641 and separator portion 642. Specifically, first electrode plate 630 is disposed on separator portion 641 so that the edge of first electrode plate 630 in the negative Z-axis direction is disposed at the position of separator folded back portion 643a, and separator portion 642 is folded back relative to separator portion 641. As a result, separator folded back portion 643a is disposed at the edge of separator 640 in the negative Z-axis direction.

[0087] 9(c), the ends of the two separator portions 641 and 642 of the separator 640 in the positive direction along the X-axis are joined together by a joining member 670 such as an adhesive (glue, etc.). Any material may be used as the joining member 670, and the ends of the separator portions 641 and 642 may be joined together by thermal welding, etc., instead of the joining member 670. The ends of the separator portions 641 and 642 are preferably joined and sealed together over their entire length in the Z-axis direction, but may be joined only partially in the Z-axis direction.

[0088] 10, the second electrode plate 650 is placed on the separator 640 sandwiching the first electrode plate 630. That is, similar to the above embodiment, the second electrode plate 650 is placed on the separator 640 so that the negative electrode composite layer 652 of the second electrode plate 650 is positioned to cover the positive electrode composite layer 632 of the first electrode plate 630. In this manner, the separator 640 sandwiching the first electrode plate 630 and the second electrode plate 650 are stacked to form an electrode body 600 as shown in (b) of FIG. 6, similar to the above embodiment. Other configurations are similar to the above embodiment, so detailed description will be omitted.

[0089] As described above, the energy storage element 10 according to this modification can achieve the same effects as those of the above embodiment. In particular, unlike the above embodiment, the separator 640 in this modification has two separator portions 641 and 642 aligned in the Z-axis direction, and sandwiches the first electrode plate 630. In this way, the energy storage element 10 that can achieve the same effects as those of the above embodiment can be manufactured by a method other than that of the above embodiment, and therefore the flexibility of the manufacturing process for the energy storage element 10 can be improved.

[0090] (Other variations) Although the energy storage element 10 according to the embodiment of the present invention (including its modified examples) has been described above, the present invention is not limited to this embodiment. In other words, the embodiment disclosed herein is illustrative in all respects, and the scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

[0091] For example, in the above embodiment, the first electrode terminal 200, the first current collector 400, and the first electrode plate 630 are a positive terminal, a positive current collector, and a positive electrode plate, and the second electrode terminal 300, the second current collector 500, and the second electrode plate 650 are a negative terminal, a negative current collector, and a negative electrode plate. However, the first electrode terminal 200, the first current collector 400, and the first electrode plate 630 may be a negative terminal, a negative current collector, and a negative electrode plate, and the second electrode terminal 300, the second current collector 500, and the second electrode plate 650 may be a positive terminal, a positive current collector, and a positive electrode plate.

[0092] In the above embodiment, the converging portion 610 (first connection portion 631a) of the electrode body 600 protrudes from an end portion of the electrode body main body 601 in the positive Z-axis direction and the negative X-axis direction, and the converging portion 620 (second connection portion 651a) protrudes from an end portion of the electrode body main body 601 in the positive X-axis direction and the positive Z-axis direction. However, the converging portion 610 may protrude from an end portion of the electrode body main body 601 in the positive Z-axis direction and the positive X-axis direction or a central portion in the X-axis direction, and the converging portion 620 may protrude from an end portion of the electrode body main body 601 in the positive X-axis direction and the negative Z-axis direction or a central portion in the Z-axis direction.

[0093] In the above embodiment, the converging portion 610 (first connection portion 631a) protrudes from the electrode body main body 601 in the positive direction of the Z axis, and the converging portion 620 (second connection portion 651a) protrudes from the electrode body main body 601 in the positive direction of the X axis. However, the converging portion 610 may protrude in the negative direction of the Z axis, or the converging portion 620 may protrude in the negative direction of the X axis, or the protruding directions of the converging portion 610 and the converging portion 620 may be reversed, or the converging portion 610 and the converging portion 620 may protrude in a direction inclined from the X axis direction or the Z axis direction. In other words, the converging portion 610 and the converging portion 620 may protrude from the electrode body main body 601 in directions intersecting each other.

[0094] In the above embodiment, the converging portion 610 is a single tab bundle protruding from a part of the end of the electrode body main body 601. However, the converging portion 610 may be a bundle of multiple tabs (a bundle of multiple tabs aligned in the X-axis direction or a bundle of multiple tabs aligned in the Y-axis direction) protruding from the electrode body main body 601. The converging portion 610 may also be a bundle of the ends of the electrode body 600 protruding from the entire end of the electrode body main body 601. In other words, the first connecting portion 631a may not be a tab protruding from a part of the edge of the electrode body main body 601, but may be a portion protruding from the entire edge of the electrode body main body 601. In this case, the form of the connection between the first connecting portion 631a and the first current collector 400 is not limited to the above, and a known configuration may be applied as appropriate. The same applies to the converging portion 620 (the second connecting portion 651a).

[0095] In the above embodiment, the first electrode plate 630, the separator 640, and the second electrode plate 650 have a rectangular shape that is long in the X-axis direction. However, the first electrode plate 630, the separator 640, and the second electrode plate 650 may have a rectangular shape that is long in the Z-axis direction, or other polygonal shapes, ellipses, ovals, circles, and the like, and the shapes are not particularly limited. Furthermore, the size and number of the first electrode plate 630, the separator 640, and the second electrode plate 650 are not particularly limited. In other words, the shape, size, and number of the first electrode plate 630, the separator 640, and the second electrode plate 650 may be any shape, size, and number as long as they do not impair the performance of the energy storage element 10. Similarly, the shape, size, and number of the first connection portion 631a and the second connection portion 651a (converging portions 610 and 620) are not particularly limited.

[0096] In the above embodiment, the separator 640 of the electrode body 600 is a single folded separator having two separator portions 641 and 642 and a separator folded portion. However, the separator 640 may be two separators corresponding to the two separator portions 641 and 642.

[0097] In the above embodiment, the first electrode terminal 200 and the second electrode terminal 300 are both arranged in the positive direction of the Z axis of the electrode body 600. However, the first electrode terminal 200 and the second electrode terminal 300 may both be arranged in the positive direction of the X axis of the electrode body 600, or may both be arranged in the negative direction of the X axis or the negative direction of the Z axis of the electrode body 600. Alternatively, the first electrode terminal 200 and the second electrode terminal 300 may be arranged on different sides of the electrode body 600 (for example, the first electrode terminal 200 in the positive direction of the Z axis of the electrode body 600, and the second electrode terminal 300 in the positive direction of the X axis of the electrode body 600).

[0098] In the above embodiment, all of the first electrode plates 630, the separators 640, and the second electrode plates 650 of the electrode assembly 600 have the above configuration. However, any of these may not have the above configuration.

[0099] Furthermore, the structures of the first electrode terminal 200, the second electrode terminal 300, the first current collector 400, the second current collector 500, and the like are not particularly limited as long as they are within the scope of the present invention. Furthermore, in the above embodiment, the first electrode terminal 200, the second electrode terminal 300, the first current collector 400, the second current collector 500, and the container 100 are electrically insulated via a gasket or the like. However, as long as the insulation between the positive and negative electrodes is ensured and there is no problem with the usage, the first electrode terminal 200, the first current collector 400, and the container 100, or the second electrode terminal 300, the second current collector 500, and the container 100 may be electrically connected.

[0100] In the above embodiment, a spacer or the like may be provided to support the second current collector 500. For example, the electrode connection portion 520 of the second current collector 500 may be extended in the negative direction of the Z axis and may be fitted into a bottom spacer arranged on the bottom side of the container body 110, thereby supporting the second current collector 500.

[0101] Furthermore, any combination of the above-described embodiments and modifications is also included within the scope of the present invention.

[0102] Furthermore, the present invention can be realized not only as such an energy storage element 10, but also as an electrode body 600, a combination of the electrode body 600 and an electrode terminal (first electrode terminal 200 and second electrode terminal 300), or a combination of the electrode body 600 and a current collector (first current collector 400 and second current collector 500). [Industrial Applicability]

[0103] The present invention can be applied to storage elements such as lithium ion secondary batteries. [Explanation of symbols]

[0104] 10 Energy storage element 100 containers 110 Container body 120 Lid 121 Gas exhaust valve 122, 123, 410, 511 Through holes 200 First electrode terminal 210, 310 Shaft 300 Second electrode terminal 400 First current collector 500 Second current collector 510 Terminal connection part 520 Electrode connection part 600 Electrode body 601 Electrode body part 610, 620 Focusing section 630 First plate 631 Positive electrode substrate 631a First connection part 632 Positive electrode composite layer 640 Separator 641, 642 Separator part 641a, 642a, 651b, 652a End 643, 643a Separator fold 650 Second plate 651 Anode Substrate 651a Second connection part 652 Negative electrode composite layer 660, 670 Joint material 700 Backing plate

Claims

1. an electrode body in which positive and negative electrode plates are stacked; a first current collector connected to a first plate having one polarity among the positive electrode plate and the negative electrode plate, and a second current collector connected to a second plate having the other polarity; a first electrode terminal connected to the first current collector and a second electrode terminal connected to the second current collector; The electrode body is A main body portion, a first connection portion that is a connection portion of the first electrode plate with the first current collector and that protrudes from the main body portion in a first direction; a second connection portion that is a connection portion of the second electrode plate with the second current collector and that protrudes from the main body portion in a second direction that intersects with the first direction, the first electrode terminal and the second electrode terminal are disposed on the same side of the electrode body; The first connection portion is a tab provided on the first electrode plate and protrudes in the first direction from a part of an edge of the second electrode plate in the first direction. Energy storage element.

2. The first connection portion protrudes in the first direction from an end portion of the main body portion opposite to the second connection portion. The energy storage element according to claim 1 .

3. The electrode assembly further includes a folded separator formed by folding back a single separator, The folded separator has two separator portions that sandwich the first electrode plate, and a separator folded portion that connects ends of the two separator portions to each other. The energy storage element according to claim 1 or 2.

4. The second connection portion is disposed so as to protrude from the separator folded-back portion. The energy storage element according to claim 3 .

5. The second connection portion is disposed on a side of the main body portion different from the second electrode terminal, and is connected to the second current collector in a state where the second connection portion is bent in a third direction intersecting the first direction and the second direction. The energy storage element according to any one of claims 1 to 4.

6. an electrode body in which positive and negative electrode plates are stacked; a first current collector connected to a first plate having one polarity of the positive electrode plate and the negative electrode plate, and a second current collector connected to a second plate having the other polarity; The electrode body is A main body portion, a first connection portion that is a connection portion of the first electrode plate with the first current collector and that protrudes from the main body portion in a first direction; a second connection portion that is a connection portion of the second electrode plate with the second current collector and that protrudes from the main body portion in a second direction that intersects with the first direction, The first connection portion is a tab provided on the first electrode plate and protrudes in the first direction from a part of an edge of the second electrode plate in the first direction. Energy storage element.

Images