Energy storage cell

Abstract

To provide a power storage cell that can suppress both the contact of a lid with an electrode body when an external force acts on the lid and a shortage of electrolyte above the electrode body.SOLUTION: A power storage cell 1 includes an electrode body 100 consisting of a wound body wound such that a plurality of positive electrode tabs 110P and a plurality of negative electrode tabs 110N protrude upward, a cell case 200, and an insulating member 500. The cell case 200 includes a case body 210 and a lid 220. The insulating member 500 includes a covering portion 530 that covers the upper surface of the electrode body 100, and the covering portion 530 has a holding portion 532 that holds the electrolyte that seeps out from the electrode body 100.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] JP 2016-152117 A discloses an electricity storage device including an electrode assembly and a case that contains the electrodes together with an electrolyte. The electrode assembly is a wound body in which a positive electrode and a negative electrode are wound in a state in which they are insulated from each other. The case has a case body that opens upward and a cover plate that closes the opening of the case body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-152117 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the secondary battery described in JP 2016-152117 A, there is a concern that the lid may come into contact with the electrode body when an external force acts on the lid from above. In addition, since the electrolyte seeps out of the electrode body when the electrode body expands and flows toward the bottom of the case, the electrolyte is likely to be insufficient, particularly in the upper part of the electrode body, when the electrode body contracts.

[0005] An object of the present disclosure is to provide an energy storage cell that can suppress both contact of the lid with the electrode body when an external force acts on the lid and a shortage of electrolyte above the electrode body. [Means for solving the problem]

[0006] A storage cell according to one aspect of the present disclosure comprises an electrode body consisting of a wound body wound so that a plurality of positive electrode tabs and a plurality of negative electrode tabs protrude upward, a cell case that houses the electrode body, and an insulating member that provides insulation between the electrode body and the cell case, wherein the cell case has a case body that houses the electrode body and has an opening that opens upward, and a lid connected to the case body so as to close the opening of the case body, and the insulating member has a covering portion that covers an upper surface of the electrode body, and the covering portion has a holding portion that holds electrolyte that seeps out from the electrode body. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a storage cell that can suppress both contact of the lid with the electrode body when an external force acts on the lid and a shortage of electrolyte above the electrode body. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view illustrating a storage cell according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is an exploded perspective view of the power storage cell shown in FIG. [Diagram 3] FIG. 2 is a cross-sectional view of the storage cell shown in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of the vicinity of the positive electrode connecting pin. [Diagram 5] FIG. 4 is a plan view illustrating a schematic view of a part of the covering portion. [Figure 6] FIG. 13 is a plan view illustrating a schematic modification of the covering portion. [Figure 7] FIG. 13 is a plan view illustrating a schematic modification of the covering portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will now be described with reference to the accompanying drawings, in which the same or corresponding components are designated by the same reference numerals.

[0010] Fig. 1 is a perspective view that shows a schematic diagram of a storage cell according to an embodiment of the present disclosure. Fig. 2 is an exploded perspective view of the storage cell shown in Fig. 1. Fig. 3 is a cross-sectional view of the storage cell shown in Fig. 1.

[0011] As shown in FIGS. 1 to 3, the energy storage cell 1 includes an electrode assembly 100, a cell case 200, an external terminal 300, a connecting member 400, and an insulating member 500. The electrode assembly 100 includes an electrode body 100, a cell case 200, an external terminal 300, a connecting member 400, and an insulating member 500.

[0012] The electrode assembly 100 has a plurality of unit electrode bodies 111, 112 and an insulating film 120. In this embodiment, the plurality of unit electrode bodies includes two unit electrode bodies 111, 112. Each unit electrode body 111, 112 includes a plurality of tabs, i.e., a plurality of positive electrode tabs 110P and a plurality of negative electrode tabs 110N. The unit electrode bodies 111, 112 have the same structure. Therefore, hereinafter, only the unit electrode body 111 will be described.

[0013] The electrode unit 111 includes a positive electrode sheet, a separator, and a negative electrode sheet. The positive electrode sheet, the negative electrode sheet, and the separator are formed into a long rectangular shape.

[0014] The positive electrode sheet includes a metal foil and a positive electrode composite layer provided on the metal foil. An uncoated portion where the positive electrode composite layer is not formed is formed on the upper long side of the metal foil, and the positive electrode tabs 110P are formed at intervals from each other in the uncoated portion.

[0015] The negative electrode sheet includes a metal foil and a negative electrode composite layer formed on the metal foil. An uncoated portion where the negative electrode composite layer is not formed is formed on the upper long side of the metal foil, and the negative electrode tabs 110N are formed at intervals from each other on the uncoated portion.

[0016] Each sheet is wound so that the positive electrode tabs 110P and the negative electrode tabs 110N protrude upward, thereby forming a unit electrode body 111. That is, the unit electrode body 111 is composed of a wound body wound so that the positive electrode tabs 110P and the negative electrode tabs 110N protrude upward. In the state where each sheet is wound, the positive electrode tabs 110P are arranged in the thickness direction (the direction perpendicular to the paper surface in FIG. 3), and the negative electrode tabs 110N are arranged in the thickness direction. The positive electrode tabs 110P and the negative electrode tabs 110N are arranged at intervals in the width direction (the direction perpendicular to both the thickness direction and the height direction).

[0017] The insulating film 120 has a shape that collectively covers the peripheral and bottom surfaces of the plurality of unit electrode bodies 111 and 112 .

[0018] The cell case 200 houses the electrode assembly 100. The cell case 200 also houses an electrolyte (not shown). The cell case 200 is sealed. The cell case 200 has a case body 210 and a lid 220.

[0019] The case body 210 has an opening 211 that opens upward. The case body 210 is made of a metal such as aluminum. The case body 210 has a bottom wall 212 and a peripheral wall 214. The bottom wall 212 is formed in a rectangular, flat plate shape. The peripheral wall 214 stands up from the bottom wall 212. The peripheral wall 214 is formed in a rectangular tube shape. The length of the peripheral wall 214 in the width direction is longer than the length of the peripheral wall 214 in the thickness direction. The length of the peripheral wall 214 in the height direction is longer than the length of the peripheral wall 214 in the thickness direction.

[0020] The lid 220 closes the opening 211 of the case body 210. The lid 220 is connected to the opening 211 by welding or the like. The lid 220 is formed in a flat plate shape. The lid 220 is made of a metal such as aluminum. The lid 220 has a lid body 222 and an inversion plate 224.

[0021] The lid body 222 is connected to the case body 210 by welding or the like. The lid body 222 is formed with a pressure release valve 222a, a liquid injection hole 222b, a sealing member 222c, and a pair of pin insertion holes 222d.

[0022] The pressure release valve 222a is formed in the center of the lid body 222. The pressure release valve 222a is formed to break when the internal pressure of the cell case 200 reaches or exceeds a predetermined pressure. When the pressure release valve 222a breaks, gas within the cell case 200 is released to the outside of the cell case 200 through the pressure release valve 222a, and the internal pressure of the cell case 200 decreases.

[0023] The liquid injection hole 222b is a through hole for injecting an electrolyte into the cell case 200 during the manufacturing process of the energy storage cell 1.

[0024] The sealing member 222c is a member that seals the liquid injection hole 222b. After the electrolyte is injected into the case body 210, the liquid injection hole 222b is sealed with the sealing member 222c.

[0025] The pair of pin insertion holes 222d are formed at an interval from each other in the width direction. Each of the pin insertion holes 222d is a through hole for inserting a connecting pin 420 described later.

[0026] The reversal plate 224 is connected to the lid body 222 by welding or the like. The reversal plate 224 has a shape that is curved so as to be convex from the outside toward the inside of the lid body 222. When the internal pressure of the cell case 200 reaches or exceeds a predetermined pressure, the reversal plate 224 deforms into a shape that is curved so as to be convex from the inside of the cell case 200 toward the outside.

[0027] The external terminal 300 is fixed to the upper surface of the cell case 200. A bus bar (not shown) is connected by welding or the like to the external terminal 300. The external terminal 300 has a positive electrode member 300P and a negative electrode member 300N.

[0028] The positive electrode member 300P is connected by welding or the like to the upper surface of the cell case 200. The positive electrode member 300P has a positive electrode terminal plate 310 and a terminal block 320.

[0029] The positive electrode terminal plate 310 is formed in a rectangular parallelepiped shape and is made of a metal such as aluminum.

[0030] The terminal block 320 is formed in a rectangular parallelepiped shape. The terminal block 320 is made of a metal (such as iron) different from the metal constituting the positive electrode terminal plate 310. The terminal block 320 is connected to the upper surface of the lid body 222 by welding, and the positive electrode terminal plate 310 is connected to the upper surface of the terminal block 320 by welding or the like. In other words, the case body 210 and the lid 220 are electrically connected to the positive electrode terminal plate 310 via the terminal block 320, and are charged with the same polarity as the positive electrode terminal plate 310. Each of the positive electrode terminal plate 310 and the terminal block 320 has a through hole formed therein for inserting a positive electrode connecting pin 420P described later.

[0031] The negative electrode member 300N is connected to the upper surface of the cell case 200 by welding or the like. The negative electrode member 300N is disposed at a distance in the width direction from the positive electrode member 300P. The negative electrode member 300N has a negative electrode terminal plate 330 and an insulating plate 340.

[0032] The negative electrode terminal plate 330 is formed in a substantially rectangular parallelepiped shape. The negative electrode terminal plate 330 is disposed above the reversal plate 224. As shown in Fig. 4, the negative electrode terminal plate 330 has a facing portion 332 that faces the reversal plate 224. When the internal pressure of the cell case 200 is less than a predetermined pressure (normal), the reversal plate 224 is spaced apart from the facing portion 332.

[0033] The insulating plate 340 is fixed to the upper surface of the lid 220. The insulating plate 340 holds the negative electrode terminal plate 330. The insulating plate 340 provides insulation between the lid 220 and the negative electrode terminal plate 330. A through hole for inserting a negative electrode connecting pin 420N described below is formed in each of the negative electrode terminal plate 330 and the insulating plate 340. As shown in FIG. 4, the insulating plate 340 has an exposure opening 342 that exposes the facing portion 332.

[0034] The connecting member 400 connects the plurality of tabs 110P, 110N to the external terminal 300. The connecting member 400 has a current collecting plate 410 and a connecting pin 420.

[0035] The current collector 410 is connected to a plurality of tabs. The current collector 410 includes a positive current collector 410P and a negative current collector 410N.

[0036] The positive electrode current collector 410P is connected to the multiple positive electrode tabs 110P by welding, etc. The positive electrode current collector 410P has a first flat plate portion 411 and a second flat plate portion 412.

[0037] A plurality of positive electrode tabs 110P are connected to the first flat plate portion 411 by ultrasonic welding or the like. Through holes are formed in the first flat plate portion 411. The plurality of positive electrode tabs 110P are connected to the lower surface of the first flat plate portion 411. However, the plurality of positive electrode tabs 110P may be connected to the upper surface of the first flat plate portion 411.

[0038] The second flat plate portion 412 is disposed on the outer side of the first flat plate portion 411 in the width direction. A connecting hole 412h and a fuse portion 412a are formed in the second flat plate portion 412. The fuse portion 412a is configured as a through hole that penetrates the second flat plate portion 412 in the thickness direction. As shown in Figs. 3 and 4, a thin portion may be formed between the second flat plate portion 412 and the first flat plate portion 411.

[0039] The negative current collector 410N is connected to a plurality of negative electrode tabs 110N by welding, etc. The configuration of the negative current collector 410N is substantially the same as the configuration of the positive current collector 410P.

[0040] The connecting pins 420 connect the current collector plate 410 and the external terminal 300. The connecting pins 420 include a positive electrode connecting pin 420P and a negative electrode connecting pin 420N.

[0041] The positive electrode connecting pin 420P connects the positive electrode current collector plate 410P and the positive electrode terminal plate 310. The positive electrode connecting pin 420P is formed in a cylindrical shape. The lower end of the positive electrode connecting pin 420P is connected to the second flat plate portion 412 in a state where it is inserted into the connecting hole 412h. The upper end of the positive electrode connecting pin 420P is crimped to the positive electrode terminal plate 310.

[0042] The negative electrode connecting pin 420N connects the negative electrode current collector plate 410N and the negative electrode terminal plate 330. The negative electrode connecting pin 420N is formed in a cylindrical shape. The lower end of the negative electrode connecting pin 420N is connected to the second flat plate portion 412 in a state where it is inserted into the connecting hole 412h. The upper end of the negative electrode connecting pin 420N is crimped to the negative electrode terminal plate 330.

[0043] The insulating member 500 provides insulation between the connecting member 400 and the cell casing 200. The insulating member 500 also provides insulation between the electrode body 100 and the cell casing 200. The insulating member 500 has an insulating sheet 510, an insulator 520, and a covering portion 530.

[0044] The insulating sheet 510 is connected to the lower surface of the lid main body 222. Through holes are formed in the insulating sheet 510 at a portion overlapping the pressure release valve 222a in the height direction, a portion overlapping the liquid injection hole 222b, a portion overlapping each pin insertion hole 222d, and a portion overlapping the reversal plate 224.

[0045] The insulator 520 has a shape that surrounds the connecting pin 420, and provides insulation between the connecting pin 420 and the cell case 200. The insulator 520 has a positive electrode side insulator 520P and a negative electrode side insulator 520N.

[0046] The positive electrode side insulator 520P covers the positive electrode connecting pin 420P. The positive electrode side insulator 520P is formed in a cylindrical shape. The positive electrode side insulator 520P insulates between the positive electrode connecting pin 420P and the lid main body 222.

[0047] The negative electrode side insulator 520N covers the negative electrode connecting pin 420N. The structure of the negative electrode side insulator 520N is the same as the structure of the positive electrode side insulator 520P.

[0048] The covering portion 530 covers the upper surface of the electrode body 100. The covering portion 530 is formed in a substantially flat plate shape. The covering portion 530 is fixed at a position where a small gap is formed between the lower surface of the covering portion 530 and the upper surface of the electrode body 100. The covering portion 530 has a holding portion 532 that holds the electrolyte solution seeping out from the electrode body 100. As shown in FIG. 5, the holding portion 532 is composed of lattice-like ribs that can hold the electrolyte solution by capillary action.

[0049] In the energy storage cell 1 described above, when the internal pressure of the cell case 200 rises to or above the predetermined pressure due to the occurrence of an abnormality in the electrode assembly 100, the reversal plate 224 is reversed (deformed into a curved shape that is convex upward) and comes into contact with the opposing portion 332 of the negative electrode terminal plate 330. As a result, the external terminal 300, the connecting member 400, and the electrode assembly 100 form a closed circuit via the lid 220, and a large current flows through this circuit. Then, the fuse portion 412a formed in the second flat plate portion 412 melts. As a result, the electrical connection between the electrode assembly 100 and the cell case 200 is cut off.

[0050] As described above, in the energy storage cell 1 of this embodiment, the covering portion 530 covers the upper surface of the electrode assembly 100, so that when an external force acts on the lid 220, the lid 220 is prevented from coming into contact with the electrode assembly 100. Furthermore, the electrolyte that seeps out from the electrode assembly 100 due to the expansion of the electrode assembly 100 during charging is held by the holding portion 532 in the covering portion 530, and is supplied from the holding portion 532 to the upper portion of the electrode assembly 100 when the electrode assembly 100 contracts during discharging. This prevents a shortage of electrolyte in the upper portion of the electrode assembly 100.

[0051] In the above embodiment, the retaining portion 532 may be formed of a honeycomb rib as shown in Fig. 6. Alternatively, as shown in Fig. 7, the retaining portion 532 may be formed of a rib in which a plurality of triangles are arranged such that one hexagon is formed by six triangles arranged in a ring shape spaced apart from one another.

[0052] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0053] [Aspect 1] an electrode assembly including a wound body wound so that a plurality of positive electrode tabs and a plurality of negative electrode tabs protrude upward; A cell case that accommodates the electrode assembly; an insulating member for insulating the electrode body from the cell casing; The cell casing comprises: a case body that houses the electrode body and has an opening that opens upward; a lid connected to the case body so as to close the opening of the case body, The insulating member has a covering portion that covers an upper surface of the electrode body, The covering portion has a holding portion that holds the electrolyte that has seeped out from the electrode body.

[0054] In this energy storage cell, the covering portion covers the upper surface of the electrode body, so that the lid is prevented from coming into contact with the electrode body when an external force acts on the lid. Furthermore, the electrolyte that seeps out from the electrode body due to expansion of the electrode body during charging is retained by the retaining portion in the covering portion, and is supplied from the retaining portion to the upper part of the electrode body when the electrode body contracts during discharging, so that a shortage of electrolyte in the upper part of the electrode body is suppressed.

[0055] [Aspect 2] 2. The energy storage cell according to claim 1, wherein the holding portion is formed of lattice-like ribs capable of holding the electrolyte by capillary action.

[0056] In this embodiment, the rigidity of the covering portion is effectively ensured by the lattice-shaped ribs, so that contact of the lid with the electrode body when an external force is applied to the lid is more reliably prevented.

[0057] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0058] 1 storage cell, 100 electrode body, 110N negative electrode tab, 110P positive electrode tab, 111, 112 unit electrode body, 120 insulating film, 200 cell case, 210 case body, 211 opening, 220 lid, 222 lid body, 224 reversal plate, 300 external terminal, 300N negative electrode member, 300P positive electrode member, 310 positive electrode terminal plate, 320 terminal block, 330 negative electrode terminal plate, 340 insulating plate, 400 connecting member, 410 current collector, 410N negative electrode current collector, 410P positive electrode current collector, 420 connecting pin, 420N negative electrode connecting pin, 420P positive electrode connecting pin, 422 coating portion, 422a fuse portion, 500 insulating member, 510 insulating sheet, 520 Insulator, 520N negative electrode side insulator, 520P positive electrode side insulator, 530 covering part, 532 holding part.

Claims

1. an electrode assembly including a wound body wound so that a plurality of positive electrode tabs and a plurality of negative electrode tabs protrude upward; A cell case that accommodates the electrode assembly; an insulating member for insulating the electrode body from the cell casing; The electrode body is Two unit electrode bodies arranged adjacent to each other; an insulating film having a shape covering the peripheral surfaces and bottom surfaces of the two unit electrode bodies collectively; The cell casing comprises: a case body that houses the electrode body and has an opening that opens upward; a lid connected to the case body so as to close the opening of the case body, the insulating member is in contact with the case body in a direction perpendicular to both the direction in which the two unit electrode bodies are adjacent to each other and the up-down direction, and has a covering portion that covers both an upper surface of the electrode body and an upper surface of the insulating film, The covering portion has a retaining portion that retains the electrolyte solution exuded from the electrode body, The holding portion includes a portion located above a portion between the unit electrode body and the insulating film.

2. The energy storage cell according to claim 1 , wherein the holding portion is formed of lattice-like ribs capable of holding the electrolyte by capillary action.

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