Power storage device

Abstract

To provide a power storage device in which a space between a current collector connected to an electrode terminal and an electrode body is reduced and a volumetric energy density is higher.SOLUTION: A power storage device includes: an electrode body having a first electrode body element and a second electrode body element; an exterior body housing the electrode body; a lid closing an opening of the exterior body; electrode terminals electrically connected to the electrode body; current collectors electrically connecting a first side first electrode plate and a second side first electrode plate of the electrode body to the electrode terminals; and insulating members disposed between the current collectors and the lid. The lid has a liquid injection hole for injecting an electrolyte into the exterior body, a first tab of the first side first electrode plate is bent toward the second electrode body element, a second tab of the second side first electrode plate is bent toward the first electrode body element, and the opening facing the lid in a hole formed in the insulating member is larger than the opening facing the electrode body, of the liquid injection hole.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a power storage device.

Background Art

[0002] A power storage device is used as a power source for driving electric vehicles (EVs), hybrid electric vehicles (HEVs, PHEVs), etc., and for electronic devices. As this power storage device, for example, an alkaline secondary battery, a non-aqueous electrolyte secondary battery, or the like is used.

[0003] These power storage devices include, for example, an electrode body, an exterior body (case) that houses the electrode body, a lid that closes an opening of the exterior body, an electrode terminal, a liquid injection hole that is a through hole provided in the lid, and a sealing member that closes the liquid injection hole. The electrode body includes a positive electrode plate, a negative electrode plate, and a separator. The electrode terminal is connected to one of the positive electrode plate and the negative electrode plate of the electrode body and penetrates through an insertion hole provided in the lid.

[0004] Patent Document 1 discloses a power storage device in which an electrolytic solution is supplied into a case from a liquid injection hole in a lid, and after the supply of the electrolytic solution is completed, the liquid injection hole is closed with a sealing member.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the power storage device as described above, it is desired to increase the volume energy density to increase the battery capacity. For this purpose, it is conceivable to reduce the distance between the lid and the electrode body.

[0007] An object of the present disclosure is to provide a power storage device with a smaller space between a current collector connected to an electrode terminal and an electrode body and a higher volume energy density.

Means for Solving the Problems

[0008] A power storage device according to an aspect of the present disclosure includes a first electrode body element including a first-side first electrode plate, a first-side second electrode plate, and a first-side separator interposed between the first-side first electrode plate and the first-side second electrode plate, an electrode body having a second electrode body element including a second-side first electrode plate, a second-side second electrode plate, and a second-side separator interposed between the second-side first electrode plate and the second-side second electrode plate, an exterior body housing the electrode body, a lid closing an opening of the exterior body, an electrode terminal electrically connected to the electrode body and having a part exposed outside the exterior body from the lid, a current collector electrically connecting the first-side first electrode plate and the second-side first electrode plate of the electrode body to the electrode terminal, and an insulating member disposed between the current collector and the lid. The first electrode body element and the second electrode body element are arranged in the short-side direction of the lid. The lid has a liquid injection hole for injecting an electrolytic solution into the exterior body. The first-side first electrode plate of the first electrode body element has a first tab connected to a first region of the current collector. The second-side first electrode plate of the second electrode body element has a second tab connected to a second region of the current collector. The first tab is bent toward the second electrode body element, and the second tab is bent toward the first electrode body element. In the insulating member, a hole is formed in a region overlapping the liquid injection hole on the surface facing the lid, and an opening of the hole facing the lid is larger than an opening of the liquid injection hole facing the electrode body. It is a power storage device.

Advantages of the Invention

[0009] According to an aspect of the present disclosure, the space between the current collector connected to the electrode terminal and the electrode body can be reduced, and a power storage device with a higher volume energy density can be obtained.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2A

Figure 2B

Figure 2C

Figure 2D

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0011] Hereinafter, the power storage device of the embodiment will be described. The drawings referred to in the description of the embodiment are schematically drawn, and the dimensional ratios of the components drawn in the drawings may be different from the actual ones. In this specification, the description of "substantially ~" is intended to include not only exactly the same but also those recognized as substantially the same, taking substantially the same as an example. Also, the term "end portion" means the end of the object and its vicinity. In addition, the shapes, materials, numbers, etc. described below are examples for explanation, and can be changed according to the specifications of the power storage device. In the following, the same components will be described with the same reference numerals.

[0012] The power storage device described below is used, for example, as a drive power source for an electric vehicle or a hybrid vehicle, or as a stationary power storage system for peak shifting of grid power.

[0013] Hereinafter, with reference to FIGS. 1 to 8, a power storage device 10 according to an example of an embodiment will be described in detail. FIG. 1 is a perspective view of the power storage device 10. FIG. 2A is a cross-sectional view taken along line A-A of FIG. 1. FIG. 2B is a view showing the positive electrode plate 13 constituting the power storage device 10, FIG. 2C is a view showing the negative electrode plate 16 constituting the power storage device 10, and FIG. 2D is a view showing the electrode body elements 12a and 12b constituting the power storage device 10. FIG. 3 is a view of the right-end portion of FIG. 1 as seen from above. FIG. 4 is a cross-sectional view taken along line B-B of FIG. 3. In FIGS. 1 to 4, the longitudinal direction (lateral direction) of the exterior body 80 is indicated by X, the thickness direction is indicated by Y, and the vertical direction, which is the height direction, is indicated by Z. X, Y, and Z are orthogonal to each other. Hereinafter, in the power storage device 10, the opening side of the exterior body 80 will be regarded as the top and the bottom side of the exterior body 80 will be regarded as the bottom for description. Top and bottom are terms used for convenience of explanation.

[0014] As shown in FIG. 1, the power storage device 10 is a rectangular non-aqueous electrolyte secondary battery, and includes an electrode body 12 (FIG. 2A) as a power generation element, an exterior body 80, and a lid 20. The electrode body 12 includes a positive electrode plate 13 (FIG. 2B), a negative electrode plate 16 (FIG. 2C), and a separator (not shown) interposed between the positive electrode plate 13 and the negative electrode plate 16. The positive electrode plate 13 corresponds to the first electrode plate, and the negative electrode plate 16 corresponds to the second electrode plate.

[0015] The outer package 80 houses the electrode body 12 together with an electrolytic solution (not shown) corresponding to a non-aqueous electrolyte, and has a bottomed substantially rectangular parallelepiped shape with an opening 81 at the upper end. An insulating sheet 82 (Fig. 2A) is interposed between the electrode body 12 and the outer package 80. The lid 20 closes the opening 81 of the outer package 80. The lid 20 is a rectangular plate having a longitudinal direction and a width direction, that is, a rectangular plate. The longitudinal direction of the lid 20 coincides with the longitudinal direction X of the outer package 80, and the width direction of the lid 20 coincides with the thickness direction Y of the outer package 80. A positive electrode terminal 30 and a negative electrode terminal 32, which are partially exposed from the lid 20 to the outside of the outer package 80, are fixed to the lid 20 and are arranged apart from each other in the longitudinal direction X of the lid 20. In the lid, a liquid injection hole 21 and an exhaust valve 25 are formed in the middle part in the longitudinal direction. The liquid injection hole 21 is arranged on the positive electrode terminal 30 side with respect to the exhaust valve 25. The liquid injection hole 21 is a hole for injecting the electrolytic solution into the outer package 80. The outer package 80 and the lid 20 are preferably each made of metal, for example, preferably made of aluminum or an aluminum alloy.

[0016] As shown in Fig. 4, the electrode body 12 includes two electrode body elements 12a and 12b arranged adjacent to each other. Each of the electrode body elements 12a and 12b has a plurality of positive electrode plates 13 and a plurality of negative electrode plates 16 laminated one by one alternately with a separator interposed therebetween. Thereby, in each of the electrode body elements 12a and 12b, the positive electrode plates 13 and the negative electrode plates 16 are laminated with a separator interposed therebetween. In the electrode body 12, the lamination direction of the positive electrode plates 13, the separator, and the negative electrode plates 16 is a direction orthogonal to the direction from the electrode body 12 toward the lid 20, and is the thickness direction Y which is orthogonal to the vertical direction.

[0017] A porous sheet having ion permeability and insulation is used as the separator. A preferred example of the power storage device 10 is a lithium ion battery.

[0018] As shown in FIG. 2B, the positive electrode plate 13 has a main body portion 14 in which active material agent layers are formed on both surfaces of a rectangular core made of, for example, aluminum foil. A positive electrode tab 15 is provided on the positive electrode plate 13. On one side in the longitudinal direction of the main body portion 14 of the positive electrode plate 13 (the right side in FIG. 2B), the positive electrode core extends from the upper end which is one end, and this extended core constitutes the extended positive electrode tab 15. The positive electrode tab 15 is electrically connected to a positive electrode terminal 30 fixed to the lid 20 via a positive electrode current collector 40 (FIG. 4) described later.

[0019] Note that the positive electrode tab may be a part of the core in this way, but other members may be connected to the core of the main body portion 14 of the positive electrode plate 13 to form an extended positive electrode tab. Further, as shown in FIG. 2B, it is preferable that a protective layer 15a having a higher electrical resistance than the active material agent layer is provided at a portion of the positive electrode tab 15 adjacent to the active material agent layer. This protective layer 15a preferably contains ceramic particles such as alumina, silica, and zirconia, and a binder. Further, it is more preferable that the protective layer 15a contains conductive particles such as a carbon material.

[0020] The active material agent layer of the positive electrode plate 13 contains, for example, an active material, a conductive agent, and a binder. Lithium nickel cobalt manganese composite oxide can be used as the active material of the positive electrode plate 13, polyvinylidene fluoride (PVdF) can be used as the binder, a carbon material can be used as the conductive agent, and N-methylpyrrolidone (NMP) can be used as the dispersion medium.

[0021] Next, a method for manufacturing the positive electrode plate 13 will be described. First, a slurry containing the above-mentioned active material, conductive agent, binder, and dispersant is prepared. This slurry is applied to both surfaces of the core of the positive electrode plate. Then, by drying this, the dispersion medium in the slurry is removed, and an active material agent layer is formed on the core. Thereafter, the active material agent layer is subjected to a compression treatment so as to have a predetermined thickness. The positive electrode plate 13 thus obtained is cut into a predetermined shape.

[0022] As shown in FIG. 2C, the negative electrode plate 16 has a main body portion 17 in which active material binder layers are formed on both surfaces of a rectangular core made of, for example, copper foil. A negative electrode tab 18 is provided on the negative electrode plate 16. On the other side in the longitudinal direction of the main body portion 17 of the negative electrode plate 16 (the left side in FIG. 2C), the core of the negative electrode extends from the upper end which is one end, and this extended core constitutes the extended negative electrode tab 18. The negative electrode tab 18 is electrically connected to the negative electrode terminal 32 fixed to the lid 20 via a negative electrode current collector 50 (FIG. 2A) described later.

[0023] Note that the negative electrode tab may be a part of the core in this way, or other members may be connected to the core of the main body portion 17 of the negative electrode plate 16 to form an extended negative electrode tab.

[0024] The active material binder layer of the negative electrode plate 16 contains, for example, an active material, a conductive agent, a binder, and a thickener. As the active material of the negative electrode plate 16, graphite can be used, as the binder styrene-butadiene rubber (SBR), as the thickener carboxymethyl cellulose (CMC), and as the dispersion medium water can be used respectively.

[0025] Next, a method for manufacturing the negative electrode plate 16 will be described. First, a slurry containing the above-mentioned active material, conductive agent, binder, and thickener is prepared. This slurry is applied to both surfaces of the core of the negative electrode plate. Then, by drying this, the dispersion medium in the slurry is removed to form an active material binder layer on the core. Thereafter, the active material binder layer is subjected to a compression treatment so as to have a predetermined thickness. The negative electrode plate 16 thus obtained is cut into a predetermined shape.

[0026] A plurality of positive electrode plates 13 (for example, 50 pieces) and a plurality of negative electrode plates 16 (for example, 51 pieces) are manufactured by the above method, and these positive electrode plates and negative electrode plates are laminated via a rectangular separator made of polyolefin to produce two laminated electrode body elements 12a and 12b (Fig. 2D). The two electrode body elements 12a and 12b are manufactured such that the positive electrode tabs 15 are laminated on one side in the longitudinal direction X of the upper end portion of each electrode body element, and the negative electrode tabs 18 are laminated on the other side in the longitudinal direction X of the upper end portion of each electrode body element. Separators are arranged on both side surfaces in the thickness direction Y of the two electrode body elements 12a and 12b, and the positive electrode plates 13, negative electrode plates 16, and separators can be fixed in a laminated state by means of a tape or the like. Alternatively, an adhesive layer may be provided on the separator so that the separator is adhered to the positive electrode plate 13 and the separator is adhered to the negative electrode plate 16, respectively. In Fig. 4, only some of the plurality of positive electrode tabs 15 are shown.

[0027] As shown in Figs. 2A and 4, the power storage device 10 further includes a positive electrode terminal 30 and a negative electrode terminal 32 that respectively penetrate through two holes in the lid 20, a positive electrode current collector 40 and a negative electrode current collector 50, a current collector holder 60, and a safety device 90. The positive electrode terminal 30 and the negative electrode terminal 32 correspond to electrode terminals. The positive electrode current collector 40 electrically connects the positive electrode terminal 30 to the electrode body 12 via the safety device 90. The negative electrode current collector 50 (Fig. 2A) electrically connects the negative electrode terminal 32 to the electrode body 12.

[0028] At the upper end portion, which is the end portion of the electrode body 12 on the lid 20 side, a plurality of positive electrode tabs 15 and a plurality of negative electrode tabs 18 are respectively stacked and connected to the positive electrode current collector 40 and the negative electrode current collector 50. The positive electrode tab 15 is connected to the positive electrode current collector 40, and the negative electrode tab 18 is connected to the negative electrode current collector 50.

[0029] As shown in Fig. 2A, the positive electrode current collector 40 includes a first current collecting plate 41 connected to the positive electrode tab 15 and a second current collecting plate 45 connected to the first current collecting plate 41 and the safety device 90. The first current collecting plate 41 and the second current collecting plate 45 are connected by overlapping and welding their respective edges.

[0030] The negative electrode current collector 50 includes a first current collector plate 51 connected to the negative electrode tab 18 and a second current collector plate 54 connected to the first current collector plate 51 and the negative electrode terminal 32. The first current collector plate 51 and the second current collector plate 54 are connected by overlapping and welding their respective edges together.

[0031] The positive electrode tab 15 is connected to the lower surface of the first current collector plate 41 of the positive electrode current collector 40, which is the surface facing the electrode body 12, and the positive electrode tab 15 is in a curved state. Also, the negative electrode tab 18 is connected to the lower surface of the first current collector plate 51 of the negative electrode current collector 50, which is the surface facing the electrode body 12, and the negative electrode tab 18 is in a curved state. Thereby, the space between each current collector 40, 50 and the electrode body 12 can be reduced, and a secondary battery with a higher volume energy density can be realized.

[0032] The current collector holder 60 is disposed and provided between the first current collector plate 41 of the positive electrode current collector 40 and the lid 20. The current collector holder 60 corresponds to an insulating member. The current collector holder 60 includes a cylindrical body 66 formed at a position that coincides with the positive electrode tab 15 in the longitudinal direction X and surrounds the opening of the liquid injection hole 21 on the lower surface, which is the surface of the lid 20 on the electrode body 12 side. The cylindrical body 66 extends from the lid 20 toward the electrode body 12. Further, a shielding portion 70 interposed between the electrode body 12 and the lid 20 is connected to the end of the cylindrical body 66 on the electrode body 12 side. Thereby, as will be described later, a power storage device 10 with a high volume energy density and high reliability can be obtained. The current collector holder 60 will be described in detail later.

[0033] The positive electrode terminal 30 is fixed to the lid 20 via a resin-made outer insulating member 100. A through hole 31 is formed in the positive electrode terminal 30, and this through hole 31 is sealed by a sealing member 33. The negative electrode terminal 32 is fixed to the lid 20 via a resin-made outer insulating member 101. The positive electrode terminal 30 and the negative electrode terminal 32 are made of metal, for example. The positive electrode terminal 30 is made of, for example, aluminum or an aluminum alloy. The negative electrode terminal 32 is made of, for example, copper or a copper alloy. It is more preferable that the negative electrode terminal 32 has a portion made of copper or a copper alloy on the inner side of the exterior body 80 and a portion made of aluminum or an aluminum alloy on the outer side of the exterior body 80.

[0034] Also, it is preferable that nickel plating or the like is applied to the surface of the negative electrode terminal 32. A hole 55 is formed in the second current collector plate 54 of the negative electrode current collector 50, and the lower end portion of the negative electrode terminal 32 is inserted into this hole 55, and the second current collector plate 54 is fixed to the lid 20 by caulking the lower end portion thereof. At this time, the second current collector plate 54 is fixed to the lid 20 with an insulating plate 102 interposed between the lid 20 and the second current collector plate 54. This insulating plate 102 extends toward the first current collector plate 51 so as to be also interposed between the first current collector plate 51 of the negative electrode current collector 50 and the lid 20.

[0035] The safety device 90 shown in FIG. 2A is, for example, a current interruption mechanism that operates when the pressure inside the exterior body 80 becomes a predetermined value or more and interrupts the conduction path between the positive electrode plate 13 (FIG. 2B) of the electrode body 12 and the positive electrode terminal 30.

[0036] The safety device 90 has a bowl-shaped conductive member 91 fixed to a portion of the lower end of the positive electrode terminal 30 that protrudes below the lid 20, and a reversing plate 93. The conductive member 91 has a hole 92 in the bottom portion of the bowl shape, and the lower portion of the positive electrode terminal 30 is inserted into this hole 92, and the conductive member 91 is fixed to the lid 20 together with the positive electrode terminal 30 by caulking this lower portion. At this time, the conductive member 91 is fixed to the lid 20 with an insulating plate 103 interposed between the lid 20 and the conductive member 91.

[0037] The inversion plate 93 is a disk having a protrusion at its center. The inversion plate 93 is arranged to close the opening below the conductive member 91, and the peripheral edge of the inversion plate 93 and the opening end of the conductive member 91 are joined by welding. The protrusion at the center of the inversion plate 93 is connected to the second current collector plate 45 of the positive current collector 40 in a state of being fitted into the hole provided in the second current collector plate 45. Thereby, the inversion plate 93 is electrically connected to the conductive member 91 and the second current collector plate 45. Note that the protrusion at the center of the inversion plate 93 does not necessarily need to be fitted into the hole of the second current collector plate, and the protrusion may be electrically connected to the surface of the second current collector plate 45 facing the lid 20 by joining.

[0038] The safety device 90 may be provided in the conductive path between the negative electrode plate 16 and the negative electrode terminal 32 of the electrode body 12. The conductive member 91 and the inversion plate 93 are made of metal. When connected to the positive electrode terminal 30, the conductive member 91 and the inversion plate 93 are made of, for example, aluminum or an aluminum alloy. When the conductive member and the inversion plate are connected to the negative electrode terminal 32, the conductive member and the inversion plate are made of, for example, copper or a copper alloy.

[0039] In the power storage device 10, it is preferable to include a safety device. However, in the present disclosure, it is not essential to include a safety device, and the safety device may be omitted.

[0040] Furthermore, the lid 20 is provided with an exhaust valve 25 that breaks when the pressure inside the outer casing 80 becomes a predetermined value or more and discharges the gas inside the outer casing 80 to the outside of the outer casing 80. Note that the operating pressure of the exhaust valve 25 is set to a value larger than the operating pressure of the safety device 90.

[0041] The lid 20 is further provided with a liquid injection hole 21 (FIG. 4). After injecting the electrolytic solution into the outer casing 80 through the liquid injection hole 21, the liquid injection hole 21 is sealed with a plug 26 (FIG. 2A) that is a rivet. At the time of injecting the electrolytic solution, a straw-shaped (tubular) nozzle 105 (FIG. 4) is inserted into the liquid injection hole 21, and the electrolytic solution is injected into the outer casing 80 through this nozzle 105.

[0042] As shown in FIGS. 2A, 4, and 8, the power storage device 10 further includes a resin current collector holder 60 having a first insulating portion 61 and a second insulating portion 64. FIG. 5 is a perspective view of the current collector holder 60. FIG. 6 is a view seen from above FIG. 5. FIG. 7 is a cross-sectional view taken along line C-C of FIG. 6. FIG. 8 is a view corresponding to an enlarged view of a D portion of FIG. 2A showing a state in which electrolyte is supplied into the exterior body 80 through the liquid injection hole 21.

[0043] The first insulating portion 61 of the current collector holder 60 is interposed between the second current collecting plate 45 of the positive electrode current collector 40 and the inversion plate 93. The second insulating portion 64 of the current collector holder 60 is interposed between the first current collecting plate 41 of the positive electrode current collector 40 and the lid 20. In FIGS. 5 to 7, the longitudinal direction of the current collector holder 60 is indicated by a, the width direction is indicated by b, and the height direction is indicated by c. a, b, and c are orthogonal to each other. The current collector holder 60 is disposed below the lid 20 in a state where the longitudinal direction a coincides with the longitudinal direction X of the power storage device 10, the width direction b coincides with the thickness direction Y of the power storage device 10, and the height direction c coincides with the vertical direction Z.

[0044] A second current collector plate 45 (FIG. 2A) is supported below the first insulating portion 61. The first insulating portion 61 is locked to the outside of a cylindrical body 104 formed on an insulating plate 103. A bowl-shaped conductive member 91 is fitted inside the cylindrical body 104. Thereby, the positive electrode current collector 40 is fixed to the lid 20. Specifically, on the back surface (the upper surface in FIG. 2A, the lower surface in FIG. 5), which is the surface of the first insulating portion 61 opposite to the surface facing the second current collector plate 45, claws (not shown) are formed at a plurality of positions. Each of the plurality of claws sandwiches an outer peripheral flange portion (not shown) formed at the lower end portion of the conductive member 91 or the outer peripheral portion of the inversion plate 93 from both the upper and lower sides with a portion different from the claws on the upper surface of the first insulating portion 61. Also, in the first insulating portion 61, wall-shaped locking portions 63 (FIG. 5) standing upright toward the lid 20 are formed at both side edges in the width direction b of the back surface. Then, the outer side surface of the cylindrical body 104 of the insulating plate 103 is locked to the locking portions 63 by protrusions (not shown) formed on the inner side surfaces of these locking portions 63. Thereby, the current collector holder 60 is fixed to the lid 20 via the insulating plate 103. A hole 61a (FIGS. 5 and 6) penetrating in the height direction c is further formed in the first insulating portion 61, and the protrusion at the center of the inversion plate 93 and the second current collector plate 45 are connected through the hole 61a.

[0045] Furthermore, a plurality of cylindrical protrusions 61b provided around the hole 61a are formed on the side surface of the electrode body of the first insulating portion 61. The plurality of protrusions 61b are inserted into a plurality of holes 46 (FIG. 2A) provided in the second current collector plate 45. After the plurality of protrusions 61b are inserted into the plurality of holes 46 of the second current collector plate 45, the portion of the protrusion 61b penetrating the hole 46 is deformed by heat caulking, whereby the second current collector plate 45 is fixed to the first insulating portion 61.

[0046] As shown in FIG. 8, the second insulating portion 64 of the current collector holder 60 and the first current collecting plate 41 of the positive current collector 40 are arranged in the vicinity of the peripheral edge of the liquid injection hole 21 of the lid 20. The first current collecting plate 41 has a through hole 42 penetrating in the vertical direction Z on the surface facing the second insulating portion 64. Further, as shown in FIGS. 6 and 8, the second insulating portion 64 has a hole 65 penetrating in the height direction c and the vertical direction Z at a position aligned with the through hole 42 of the first current collecting plate 41. This hole 65 is an ellipse long in the longitudinal direction a of the current collector holder 60. And on the surface of the second insulating portion 64 on the electrode body 12 side, a cylindrical body 66 extending from the lid 20 side toward the electrode body 12 side is formed at the opening peripheral edge of the hole 65. The cylindrical body 66 has two flat portions 67 parallel to the outer peripheral surface according to the shape of the hole 65, and the cross-sectional shape is an ellipse long in the longitudinal direction a. Thereby, the cylindrical body 66 extends downward in the direction from the lid 20 toward the electrode body 12 so as to surround the opening of the liquid injection hole 21 on the lower surface which is the surface of the lid 20 on the electrode body side. Also, the cylindrical body 66 is disposed between the upper surface which is the outer surface of the lid 20 and the electrode body 12. Further, this cylindrical body 66 is inserted into the through hole 42 of the first current collecting plate 41. When the positive tab 15 is joined to the surface of the first current collecting plate 41 facing the electrode body 12, the tip of the positive tab 15 faces the flat portion 67 on the outer peripheral surface which is the side surface of the cylindrical body 66.

[0047] With such a cylindrical body 66, when the positive tab 15 is joined to the first current collecting plate 41, it is possible to suppress the tip of the positive tab 15 from being erroneously arranged to enter below the through hole 42 of the first current collecting plate 41. And it is possible to suppress the positive tab 15 from closing the lower sides of the through hole 42 and the liquid injection hole 21.

[0048] In the above-mentioned cylindrical body 66, a shielding portion 70 interposed between the electrode body 12 and the liquid injection hole 21 is connected to the opening end portion on the side of the electrode body 12. Specifically, two substantially parallel plate-shaped protrusions 68 are formed at two positions on the side of the electrode body 12 with different 180-degree phases at the end on the side of the electrode body 12 of the cylindrical body 66, which are portions extending downward on the side of the electrode body 12. And at the tips of these two protrusions 68, both ends in the width direction b, which is the first direction, of the elongated flat plate-shaped shielding portion 70 are connected, and the shielding portion 70 is composed of a plate linearly extending in the width direction b. The width direction b is parallel to the width direction of the lid 20 (FIGS. 1 and 2A) and corresponds to the first direction. Thereby, the shielding portion 70 is formed on the end side on the side of the electrode body 12 among both ends in the direction from the lid 20 toward the electrode body 12 in the cylindrical body 66. Also, between the end on the side of the electrode body 12 of the cylindrical body 66 and the shielding portion 70, two openings 73 are formed. Each opening 73 is an outlet for ejecting the electrolyte flowing from the side of the lid 20 to the side of the electrode body 12 into the cylindrical body 66. As shown in FIGS. 4 and 8, in a state where the current collector holder 60 is assembled below the lid 20, both side surfaces of the shielding portion 70 in the vertical direction Z are parallel to a plane orthogonal to the vertical direction Z. The shielding portion 70 is a portion that changes the flow of the electrolyte colliding from above, which is the side of the lid 20, to a direction different from the directly downward direction, which is the side of the electrode body 12.

[0049] When supplying the electrolyte into the exterior body 80 through the liquid injection hole 21, for example, as shown in FIG. 8, the nozzle 105 is inserted into the liquid injection hole 21 from above the lid 20. At this time, the lower end of the nozzle 105 faces the upper surface of the shielding portion 70 with a gap. In this state, the electrolyte is flowed through the nozzle 105 from above in the direction indicated by the arrow α in FIG. 8. The electrolyte ejected from the lower end of the nozzle 105 collides with the upper surface of the shielding portion 70, and the flow of the electrolyte is changed from the direction of the arrow α in FIG. 8 to the direction of the arrow β in FIG. 8, which is the substantially longitudinal direction X, and after being ejected to the outside of the cylindrical body in the substantially longitudinal direction X through the two openings 73, it flows down.

[0050] Next, a method of attaching the positive electrode terminal 30, the safety device 90, and the positive electrode current collector 40 to the lid 20 will be described with reference to FIG. 2A. The positive electrode terminal 30 is inserted into the hole of the lid 20 through the outer insulating member 100, and the portion of the positive electrode terminal 30 on the electrode body 12 side is inserted into the holes 92 of the insulating plate 103 and the conductive member 91. Then, the end of the positive electrode terminal 30 on the electrode body 12 side is caulked to fix the positive electrode terminal 30 to the lid 20. Then, the periphery of the reversing plate 93 is joined to the open end of the conductive member 91. Thereafter, the conductive member 91 is fixed to the first insulating portion 61 by the claws of the first insulating portion 61 of the current collector holder 60. At the same time, the locking portion 63 (FIG. 5) of the first insulating portion 61 is locked to the insulating plate 103. Further, after the protrusion 61b of the first insulating portion 61 is inserted into the hole 46 of the second current collecting plate 45 of the positive electrode current collector 40, heat caulking is performed on the tip of the protrusion 61b. Then, the protrusion of the reversing plate 93 is fitted into the hole of the second current collecting plate 45, and the interface between these holes and the protrusion is joined by laser welding.

[0051] Furthermore, a positive electrode tab 15 is joined to the surface of the first current collecting plate 41 of the positive electrode current collector 40 facing the electrode body 12. With the cylindrical body 66 of the current collector holder 60 inserted into the through hole 42 of the first current collecting plate 41, the first current collecting plate 41 to which the positive electrode tab 15 is joined is disposed on the second insulating portion 64. At this time, a part of the edge of the first current collecting plate 41 overlaps with a part of the edge of the second current collecting plate 45, and this overlapping portion is joined by welding. Thereafter, a cover (not shown) can be provided so as to cover the surface of the second current collecting plate 45 facing the electrode body 12.

[0052] As shown in FIG. 4, the electrode body 12 is composed of electrode body elements 12a and 12b divided into two, and each electrode body element 12a, 12b is connected to the positive electrode current collector 40 and the negative electrode current collector 50 (FIG. 2A). Thereby, in the first current collecting plate 41, the positive electrode tabs 15 extending from each of the electrode body elements 12a, 12b are joined to the surface of the first current collecting plate 41 on the electrode body 12 side with the cylindrical body 66 disposed between the positive electrode tabs 15.

[0053] According to the above-described power storage device 10, when the electrolytic solution is supplied into the exterior body 80 through the liquid injection hole 21, the electrolytic solution can flow toward the electrode body 12 within the exterior body 80 in a state where the flow velocity is decreased by colliding with the shielding portion 70. For this reason, it is possible to reduce the flow velocity of the electrolytic solution when the electrolytic solution collides with the upper end of the electrode body 12 within the exterior body 80. Therefore, it is possible to suppress the occurrence of damage, peeling, and slipping of the material of the electrode body 12. Furthermore, the distance between the lid 20 and the electrode body can be reduced. As a result, a power storage device 10 with a high volume energy density and high reliability can be obtained.

[0054] Furthermore, in the electrode body 12, the positive electrode plate 13 and the negative electrode plate 16 are laminated via a separator, and the lamination direction of the positive electrode plate 13, the separator, and the negative electrode plate in the electrode body 12 is a direction orthogonal to the vertical direction Z from the electrode body toward the lid. As a result, the electrolytic solution tends to collide with the overlapping portion of the edges of the positive electrode plate 13, the separator, and the negative electrode plate 16. Even in this case, however, peeling and slipping of the material can be suppressed, so that the effect according to the present disclosure becomes remarkable. For example, in a configuration where the lamination direction of the positive electrode plate 13, the negative electrode plate 16, and the separator is orthogonal to the vertical direction Z, the edges of the laminated positive electrode plate, negative electrode plate, and separator are located at the upper end of the electrode body 12. In such a configuration, if the electrolytic solution collides with the edge of the electrode body 12 at a high speed, the separator adhered to the electrode plate may peel off from the electrode plate, or the active material layer of the electrode plate may slip off. According to the configuration of the present disclosure, such inconveniences can be suppressed. Therefore, the electrode body used in the power storage device of the present disclosure is not a laminated electrode body, and even if it is a wound electrode body arranged such that the winding axis extends from the electrode body toward the lid, since the lamination direction of the positive electrode plate, the negative electrode plate, and the separator is a direction orthogonal to the vertical direction Z, the effect of suppressing damage to the electrode body can be sufficiently obtained.

[0055] Also, in the above-described shielding portion 70, the portion facing the electrode body 12 and the liquid injection hole 21 is plate-shaped, and the first direction in which this facing portion extends is parallel to the width direction of the lid 20. Thereby, the ejection direction of the electrolytic solution from the lower side of the cylindrical body 66 becomes the substantially longitudinal direction X in the inner space of the rectangular parallelepiped-shaped exterior body 80 according to the shape of the lid 20, so that the electrolytic solution can be ejected toward a wider space within the exterior body 80. For this reason, the flow velocity of the electrolytic solution when it collides with the electrode body 12 can be further reduced.

[0056] Furthermore, the two openings 73 formed at the end of the cylindrical body 66 on the electrode body 12 side are separated in the longitudinal directions X and a by the shielding portion 70. With this configuration, the electrolytic solution flowing toward the electrode body 12 within the exterior body 80 can be dispersed, and damage, peeling, and slippage of the electrode body 12 can be further suppressed. At this time, by making a part of the edge of each opening 73 higher than the upper surface of the shielding portion 70, the electrolytic solution ejected from the opening 73 can be spread and dispersed over a wider range and then flowed toward the electrode body 12, so that the flow velocity of the electrolytic solution when it collides with the electrode body 12 can be more easily reduced.

[0057] Also, the shielding portion 70 does not necessarily have to be constituted by only one, and it may be in a shape in which a plurality of them are connected to the cylindrical body 66. At this time, the plurality of shielding portions may be provided at different height positions in the cylindrical body 66. For example, the shielding portion may be connected at both ends in the width direction, which is the first direction, at two positions of the cylindrical body and may extend in the width direction. Also, the end of the cylindrical body 66 on the electrode body 12 side may be closed with a plate-shaped shielding portion 70, and openings for ejecting the electrolytic solution may be formed at at least one or more positions on the outer peripheral surface of the cylindrical body 66.

[0058] Furthermore, the shielding portion 70 may be provided at the lower end side, for example, a position close to the lower end among both upper and lower ends in the vertical direction in which the cylindrical body 66 extends. With this configuration, the nozzle of the supply source for supplying the electrolytic solution into the cylindrical body 66 can be inserted through the liquid injection hole 21. Therefore, it is possible to suppress the electrolytic solution supplied from the nozzle from scattering outside the exterior body 80. Furthermore, it is easy to prevent the nozzle from hitting the shielding portion, and it becomes easy to secure the distance between the nozzle and the shielding portion. For this reason, it becomes easy to secure the flow path of the electrolytic solution from the nozzle toward the shielding portion, and it is possible to suppress the supply of the electrolytic solution from the nozzle into the exterior body 80 from being obstructed.

[0059] Further, the cylindrical body 66 has an elliptical cross-section having two flat portions 67 parallel to the outer peripheral surface, and when joining the positive electrode tab 15 to the first current collector plate 41 of the positive electrode current collector 40, the positive electrode tab 15 before joining can be brought into contact with the flat portion 67 of the cylindrical body 66. Thereby, the arrangement of the positive electrode tab 15 before joining can be stabilized. Also, after the cylindrical body 66 is inserted into the through hole 42 of the first current collector plate 41, it is possible to suppress the first current collector plate 41 from rotating around the cylindrical body 66.

[0060] FIG. 9 and FIG. 10 are views corresponding to part E of FIG. 8 in another example of the embodiment of the present disclosure. In the configuration of the alternative example shown in FIG. 9, the shielding portion 70a connected to the cylindrical body 66 of the current collector holder 60a has a protruding portion 74 on the upper surface which is the surface on the side facing the liquid injection hole 21 (FIG. 8). The protruding portion 74 has a substantially mountain-shaped cross-section having an intermediate flat portion 75a parallel to the vertical direction on the upper surface and two outer flat portions 75b adjacent to both sides of the intermediate flat portion 75a and inclined with respect to the vertical direction. Each outer flat portion 75b corresponds to an inclined surface. Thereby, the protruding portion 74 has a trapezoidal shape in the cross-section perpendicular to the first direction (width direction b). For this reason, the flow of the electrolytic solution flowing through the nozzle 105 is changed from the downward arrow α direction to the obliquely downward arrow γ direction, and is ejected into the exterior body 80 (FIGS. 2A and 8) through the two openings 73.

[0061] In the configuration of another example shown in FIG. 10, the shielding portion 70b connected to the cylindrical body 66 of the current collector holder 60b has a protruding portion 76 on the upper surface, which is the surface on the side facing the liquid injection hole 21 (FIG. 8). The protruding portion 76 has a cross-sectional mountain shape having two flat portions 76a inclined in the direction opposite to the vertical direction on the upper surface. As a result, the protruding portion 76 has a triangular shape in a cross-section perpendicular to the first direction (width direction b). Each flat portion 76a corresponds to an inclined surface. For this reason, the flow of the electrolytic solution flowing through the nozzle 105 is changed from the downward arrow α direction to the obliquely downward arrow δ direction, and is ejected into the exterior body 80 (FIGS. 2A and 8) from the two openings 73.

[0062] Also, the end portion in the first direction (width direction b), which is the extending direction, of the shielding portion 70 may be arranged so as to face the positive electrode tab 15 or the negative electrode tab 18. With this configuration, the electrolytic solution ejected from the opening 73 is likely to be ejected parallel to the surface of the tab facing the shielding portion 70, and it is possible to suppress the electrolytic solution from being ejected toward the tab. Further, since the ejection of the electrolytic solution from the cylindrical body 66 toward the tab is suppressed, it becomes easy to arrange the tab and the cylindrical body 66 to face each other. Thereby, when the tab and the cylindrical body 66 are opposed to each other, particularly in the tab, damage to the electrode plate connected to the tab (the tab closest to the cylindrical body 66 among the plurality of tabs) opposed to the cylindrical body 66 is suppressed. In particular, damage to the active material layer on the surface of the electrode plate facing the cylindrical body 66 or the separator facing the active material layer can be reduced.

[0063] The shapes of the shielding portions 70, 70a, and 70b constituting the structure of the present disclosure are not limited to the configurations of the above examples. For example, the shielding portion may have a protruding portion on the upper surface, and the protruding portion may have a curved surface such as a curved surface in which the upper surface bulges upward along a curve. For example, the protruding portion may have a curved surface in which the shape of a cross-section perpendicular to the first direction, which is the extending direction of the shielding portion, is an arc shape, for example, a semi-circle.

[0064] In the above description, the case where the electrode body 12 is composed of the electrode body elements 12a and 12b divided into two, and the positive electrode tab 15 and the negative electrode tab 18 extend from each electrode body element was explained. On the other hand, the electrode body 12 can also be composed of only one electrode body element having a positive electrode tab and a negative electrode tab.

[0065] In addition, in the above-described embodiment, the case where the cylindrical body 66 and the shielding portions 70, 70a, 70b are part of the current collector holders 60, 60a, 60b was explained, but the power storage device of the present disclosure is not limited to this configuration. For example, the second insulating portion 64 of the current collector holder and the first current collector plate 41 may not be located in the vicinity of the peripheral portion of the liquid injection hole 21, and the second insulating portion 64 and the first current collector plate 41 may be separated from the peripheral portion of the liquid injection hole 21. In this case, a current collector holder having no cylindrical body and shielding portion and an insulating member having a cylindrical body and a shielding portion may be provided, and the power storage device of the present disclosure may be configured by arranging the insulating member in the vicinity of the liquid injection hole 21. Also in this case, the cylindrical body is disposed between the outer surface of the lid and the electrode body. Further, a part of the insulating plates 102, 103 may be extended to the vicinity of the liquid injection hole 21, and the cylindrical body 66 may be fixed to the extended portion. Furthermore, the cylindrical body does not necessarily have to be made of an insulating material. For example, it may be composed of a metal cylindrical body and a shielding portion. Therefore, the cylindrical body may be provided on the electrode body side integrally with the lid, disposed between the outer surface of the lid and the electrode body, and extend from the lid toward the electrode body so as to surround the opening of the liquid injection hole on the surface of the lid on the electrode body side. Thus, the cylindrical body may be provided as a separate member from the lid or as a part integral with the lid.

Description of Reference Numerals

[0066] 10 Energy storage device, 12 Electrode body, 12a, 12b Electrode body elements, 13 Positive electrode plate, 14 Body part, 15 Positive electrode tab, 15a Protective layer, 16 Negative electrode plate, 17 Body part, 18 Negative electrode tab, 20 Cover, 21 Liquid injection hole, 24 Exhaust valve, 25 Exhaust valve, 26 Plug, 30 Positive electrode terminal, 32 Negative electrode terminal, 33 Sealing member, 40 Positive electrode current collector, 41 First current collecting plate, 42 Through hole, 45 Second current collecting plate, 46 Hole, 50 Negative electrode current collector, 51 First current collecting plate, 54 Second current collecting plate, 55 Hole, 60, 60a, 60b Current collector holder, 61 First insulating part, 61a Hole, 61b Projection, 63 Locking part, 64 Second insulating part, 65 Hole, 66 Cylindrical body, 67 Flat part, 68 Projection, 70, 70a, 70b Shielding part, 73 Opening, 74 Protrusion, 75a Intermediate flat part, 75b Outer flat part, 76 Projection, 76a Flat part, 80 Exterior body, 81 Opening, 82 Insulating sheet, 90 Safety device, 91 Conductive member, 92 Hole, 93 Reversing plate, 100, 101 Outer insulating member, 102, 103 Insulating plate, 104 Cylindrical body, 105 Nozzle.

Claims

【Claim 1】 A first electrode body element including a first first-side electrode plate, a first second-side electrode plate, and a first-side separator interposed between the first first-side electrode plate and the first second-side electrode plate; and a second electrode body element including a second first-side electrode plate, a second second-side electrode plate, and a second-side separator interposed between the second first-side electrode plate and the second second-side electrode plate; an electrode body having the same; An exterior body housing the electrode body; A lid closing an opening of the exterior body; An electrode terminal electrically connected to the electrode body and having a part exposed outside the exterior body from the lid; A current collector electrically connecting the first first-side electrode plate and the second first-side electrode plate of the electrode body to the electrode terminal; An insulating member disposed between the current collector and the lid; The first electrode body element and the second electrode body element are arranged in the short side direction of the lid; The lid has a liquid injection hole for injecting an electrolytic solution into the exterior body; The first first-side electrode plate of the first electrode body element has a first tab connected to a first region of the current collector; The second first-side electrode plate of the second electrode body element has a second tab connected to a second region of the current collector; The first tab is bent toward the second electrode body element; The second tab is bent toward the first electrode body element; In the insulating member, a hole is formed in a region overlapping the liquid injection hole on the surface facing the lid; An opening of the hole facing the lid is larger than an opening of the liquid injection hole facing the electrode body; A power storage device.

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