JP2016021349A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery which enables the increase in production efficiency, and the cutting in a manufacturing cost.SOLUTION: A nonaqueous electrolyte secondary battery according to an embodiment hereof comprises: an outer container; an electrode group; electrode terminals; leads; and an insulating member. The outer container has a spout for pouring a nonaqueous electrolyte. The electrode group is enclosed in the outer container. The electrode terminals are attached on the outer container and exposed to the outside. The leads connect between the electrode group and the electrode terminals in the outer container. The insulating member is provided between the outer container and the leads. The spout can be opened and closed by a plug member coupled to the insulating member.SELECTED DRAWING: Figure 5

Description

  Embodiments described herein relate generally to a non-aqueous electrolyte secondary battery.

  Conventionally, non-aqueous electrolyte secondary batteries have been widely used as a power source for electric vehicles, hybrid vehicles, electric bicycles, and the like, and a power source for various electric devices. A nonaqueous electrolyte secondary battery is configured such that an electrode group is housed together with a nonaqueous electrolyte in a rectangular parallelepiped or cylindrical outer container.

  By the way, in the non-aqueous electrolyte secondary battery mentioned above, after injecting a non-aqueous electrolyte into an exterior container through a liquid inlet, it charges in the state which sealed the liquid inlet temporarily (henceforth temporary sealing). Then, aging may be performed after that. In this case, after the aging, the injection port is opened, and the gas generated in the outer container by aging (for example, the gas generated from the electrode group or the non-aqueous electrolyte) is released. Thereafter, the sealing plate is fixed to the outer container, whereby the liquid injection port is sealed again (hereinafter referred to as main sealing), and the nonaqueous electrolyte secondary battery is completed.

  However, the non-aqueous electrolyte secondary battery described above still has room for improvement in terms of improving manufacturing efficiency and reducing manufacturing costs.

JP 2000-123875 A JP 2000-353547 A JP 2008-41548 A

  The problem to be solved by the present invention is to provide a non-aqueous electrolyte secondary battery capable of improving the production efficiency and reducing the production cost.

  The nonaqueous electrolyte secondary battery of the embodiment includes an outer container, an electrode group, an electrode terminal, a lead, and an insulating member. The exterior container has a non-aqueous electrolyte injection port. The electrode group is housed in an outer container. The electrode terminal is attached to the exterior container and exposed to the outside. The lead connects between the electrode group and the electrode terminal in the exterior container. The insulating member is disposed between the outer container and the lead. The liquid injection port can be opened and closed by a plug member provided continuously with the insulating member.

The perspective view of the nonaqueous electrolyte secondary battery in an embodiment. The disassembled perspective view of the nonaqueous electrolyte secondary battery in embodiment. The disassembled perspective view of the nonaqueous electrolyte secondary battery in embodiment. The perspective view which expanded a part of electrode group in an embodiment. Sectional drawing equivalent to the AA line of FIG. It is sectional drawing equivalent to the AA line of FIG. 1, Comprising: The figure which shows the state before liquid injection. It is sectional drawing equivalent to the AA line of FIG. 1, Comprising: The figure for demonstrating opening operation | movement of a plug member. It is sectional drawing equivalent to the AA line of FIG. 1, Comprising: The figure for demonstrating the closing operation of a plug member. It is sectional drawing corresponded to the AA line of FIG. 1, Comprising: The figure which shows the state which fractured | ruptured the operation part.

Hereinafter, the nonaqueous electrolyte secondary battery of the embodiment will be described with reference to the drawings.
As shown in FIGS. 1-3, the nonaqueous electrolyte secondary battery 1 of this embodiment is a nonaqueous electrolyte secondary battery, such as a lithium ion battery, for example. Specifically, the non-aqueous electrolyte secondary battery 1 includes a bottomed cylindrical case body 2, an electrode group 3 (see FIG. 2) housed in the case body 2 together with the non-aqueous electrolyte, and an opening of the case body 2. And a sealing member 4 for sealing the part.

  The case body 2 has a flat rectangular parallelepiped shape. The case body 2 is made of, for example, aluminum, aluminum alloy, iron, nickel-plated iron, stainless steel, or the like. In the following description, the height direction of the case body 2 may be simply referred to as the height direction, and the in-plane directions orthogonal to the height direction may be referred to as the longitudinal direction and the short direction.

  As shown in FIG. 4, the electrode group 3 has a sheet-like positive electrode 11 and a negative electrode 12 wound around a separator 13, and has a flat shape matching the inner shape of the case body 2. Specifically, the electrode group 3 is configured such that the positive electrode 11 and the negative electrode 12 are displaced from each other along the winding axis, and are wound with the separator 13 interposed between the overlapping portions. Therefore, in the electrode group 3, the outer peripheral surface of the polymerized portion of the positive electrode 11, the negative electrode 12, and the separator 13 is constituted by the separator 13.

  The positive electrode 11 of the electrode group 3 includes a positive electrode active material layer 11a positioned at a polymerization portion between the negative electrode 12 and the separator 13, and a positive electrode tab 11b protruding toward one side with respect to the polymerization portion. On the other hand, the negative electrode 12 of the electrode group 3 includes a negative electrode active material layer 12a positioned at a polymerization portion with the positive electrode 11 and the separator 13, and a negative electrode tab 12b protruding toward the other side with respect to the polymerization portion. Yes.

The material of the positive electrode 11 is not particularly limited, and various oxides such as lithium-containing cobalt oxide (for example, LiCoO ₂ ), manganese dioxide, lithium manganese composite oxide (for example, LiMn ₂ O _4). , LiMnO ₂ ), lithium-containing nickel oxide (eg, LiNiO ₂ ), lithium-containing nickel cobalt oxide (eg, LiNi _0.8 Co _0.2 O ₂ ), lithium-containing iron oxide, vanadium oxidation including lithium, etc. Or a chalcogen compound containing titanium disulfide, molybdenum disulfide, or the like can be used.
Further, the material of the negative electrode 12 is not particularly limited, and for example, a graphite material or a carbonaceous material (for example, graphite, coke, carbon fiber, spherical carbon, pyrolytic gas phase carbonaceous material, resin fired body, etc. ), Chalcogen compounds (eg, titanium disulfide, molybdenum disulfide, niobium selenide, etc.), light metals (eg, aluminum, aluminum alloys, magnesium alloys, lithium, lithium alloys, etc.), lithium titanium oxides (eg, spinel type titanium) Lithium acid) or the like can be used.

  Furthermore, as a material of the separator 13, for example, a microporous film, a woven fabric, a nonwoven fabric, a laminate of the same material or different materials among these can be used. As a material for forming the separator 13, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, cellulose, or the like can be used.

  As shown in FIG. 2, the electrode group 3 is accommodated in the case body 2 in a state in which the winding axis direction coincides with the longitudinal direction. Therefore, in the case body 2, the electrode group 3 has the positive electrode tab 11 b located on one side in the longitudinal direction and the negative electrode tab 12 b located on the other side in the longitudinal direction. Further, the electrode group 3 is impregnated with a non-aqueous electrolyte in the case body 2. The non-aqueous electrolyte is prepared by dissolving an electrolyte (for example, a lithium salt) in a non-aqueous solvent.

  As shown in FIGS. 2 and 3, in the electrode group 3, leads (positive electrode lead 15 and negative electrode lead 16) made of aluminum, aluminum alloy, or the like are connected to the positive electrode tab 11 b and the negative electrode tab 12 b, respectively. .

The positive electrode lead 15 includes a connection plate 15a and a current collecting portion 15b that bifurcates from an outer end in the longitudinal direction of the connection plate 15a.
The connection plate 15a is positioned closer to the opening than the electrode group 3 (positive electrode tab 11b) in the case main body 2, and is extended in a state where the thickness direction coincides with the height direction.
The current collector 15b extends along the height direction and sandwiches the positive electrode tab 11b from both sides in the short direction.

The negative electrode lead 16 has the same configuration as that of the positive electrode lead 15 described above, and includes a connection plate 16a and a current collecting portion 16b that bifurcates from the outer end in the longitudinal direction of the connection plate 16a.
The connection plate 16a is located closer to the opening than the electrode group 3 (negative electrode tab 12b) in the case body 2.
The current collector 16b extends along the height direction and sandwiches the negative electrode tab 12b from both sides in the short direction.

  Further, the connecting portion between the positive electrode tab 11b and the current collecting portion 15b of the positive electrode lead 15 and the connecting portion between the negative electrode tab 12b and the current collecting portion 16b of the negative electrode lead 16 are individually covered by the vibration absorbing member 21 made of an insulating material. Has been. These vibration absorbing members 21 are fixed to each connection portion by an insulating tape 22 folded in half in the height direction. Thereby, the insulation between each connection part and the case main body 2 is achieved.

  The vibration absorbing member 21 can be any resin as long as it is not easily attacked by the non-aqueous electrolyte. For example, polyethylene, polypropylene, ethylene vinyl acetate copolymer, ethylene vinyl acetate alcohol copolymer, Ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl acrylate copolymer, ethylene methacryl acrylate copolymer, ethylene / methyl methacrylic acid copolymer, Akiho Mer, polyacrylonitrile, polyvinylidene chloride Polytetrafluoroethylene, polychlorotrifluoroethylene, polyphenylene ether, polyethylene terephthalate, polytetrafluoroethylene and the like can be used. Moreover, the resin mentioned above may be used alone or in a mixture of a plurality of types. Among these, it is preferable to use polypropylene or polyethylene.

  The sealing member 4 includes a lid 31 that closes the opening of the case body 2, terminals (a positive terminal 32 and a negative terminal 33) attached to the lid 31, and an inner surface (positioned on the case body 2 side) of the lid 31. And an insulating member 34 disposed on the surface. The case body 2 and the lid body 31 described above constitute the outer container of the present embodiment.

  As shown in FIGS. 3 and 5, the lid 31 is formed in a plate shape made of the same material as that of the case body 2 described above. The lid body 31 is formed with a liquid injection port 36 that penetrates the lid body 31 in the height direction. The liquid injection port 36 is a through-hole for injecting the non-aqueous electrolyte into the non-aqueous electrolyte secondary battery 1. After the non-aqueous electrolyte is injected, the sealing plate 41 is formed from the outside of the lid 31. It is blocked by The sealing plate 41 is joined to the lid 31 by laser welding or the like.

The insulating member 34 includes a base portion 42 disposed between the connection plates 15a and 16a and the lid 31 and an surrounding wall 43 erected from the outer peripheral edge of the base portion 42 toward the inside in the height direction. And have.
The surrounding wall 43 surrounds the periphery of the connection plates 15a and 16a separately.

  The terminals 32 and 33 are respectively attached to the connection plates 15a and 16a described above at the both end portions in the longitudinal direction of the lid body 31 via gaskets 45 at positions overlapping with the connection plates 15a and 16a. Each terminal 32, 33 penetrates through the lid 31, and one end in the height direction is electrically connected to the leads 15, 16 on the inner surface side of the lid 31 (inside the nonaqueous electrolyte secondary battery 1). ing. Further, the other end portions of the terminals 32 and 33 in the height direction are exposed on the outer surface side of the lid body 31 (outside of the nonaqueous electrolyte secondary battery 1).

Specifically, one end portion in the height direction of the positive electrode terminal 32 is caulked and fixed to the cover body 31, the insulating member 34 (base portion 42), and the connection plate 15 a of the positive electrode lead 15. Note that at least a part of the contact portion between the positive electrode terminal 32 and the lid 31 and the contact portion between the positive electrode terminal 32 and the connection plate 15a may be welded.
Further, one end of the negative electrode terminal 33 in the height direction is fixed by caulking to the lid 31, the insulating member 34 (base portion 42), and the connection plate 16 a of the negative electrode lead 16. Note that at least a part of the contact portion between the negative electrode terminal 33 and the lid 31 and the contact portion between the negative electrode terminal 33 and the connection plate 16a may be welded.

  Here, as shown in FIG. 5, a plug member 51 that opens and closes the liquid injection port 36 of the lid 31 from the inside of the nonaqueous electrolyte secondary battery 1 is connected to the insulating member 34 described above. That is, the plug member 51 is integrally formed with the insulating member 34 by resin molding or the like. The insulating member 34 and the plug member 51 can be formed of the same material as that of the vibration absorbing member 21 described above.

The plug member 51 includes a plug body 52 that is fitted to the liquid injection port 36 and a connecting portion 53 that connects the plug body 52 and the insulating member 34.
The connecting portion 53 is cantilevered along the longitudinal direction and is elastically deformable along the height direction. Specifically, the connecting portion 53 has one end portion in the longitudinal direction connected to the inner end portion in the longitudinal direction of the surrounding wall 43 located on one terminal side (in the present embodiment, the positive electrode terminal 32 side). And the connection part 53 is extended in the state which opened the clearance gap between the inner surfaces of the cover body 31 in the height direction. Further, the other end portion in the longitudinal direction of the connecting portion 53 extends to a position overlapping the liquid injection port 36 in the height direction.

  The plug body 52 has an outer peripheral surface shape that matches the inner surface shape of the liquid injection port 36, and is connected to the other end portion of the connecting portion 53. The plug body 52 is located on the inner side in the height direction with respect to the outer opening edge of the liquid injection port 36 in a state of being fitted in the liquid injection port 36.

  As shown in FIG. 6, the plug body 52 has a plug body in a stage before the sealing plate 41 is joined to the lid body 31 in the manufacturing process of the non-aqueous electrolyte secondary battery 1 described later. An operation unit 55 for opening and closing 52 is continuously provided. Specifically, the operation portion 55 is extended along the height direction, and one end portion of the operation portion 55 is connected to the plug body 52 via the thin portion 56 so as to be breakable. Further, the other end of the operation unit 55 is drawn to the outside of the nonaqueous electrolyte secondary battery 1 through the liquid injection port 36. Accordingly, the plug 52 can be opened and closed from the outside of the nonaqueous electrolyte secondary battery 1 through the operation unit 55.

Next, as a function of the nonaqueous electrolyte secondary battery 1 of the present embodiment, a manufacturing process of the nonaqueous electrolyte secondary battery 1 will be briefly described. In the following description, after the sealing member 4 is attached to the case main body 2, a description will be given from the stage before injecting the non-aqueous electrolyte.
First, a nonaqueous electrolytic solution is injected into the nonaqueous electrolyte secondary battery 1. Specifically, as shown in FIG. 7, the plug member 51 is pushed inward in the height direction via the operation unit 55 to open the liquid injection port 36. When the plug member 51 is pushed in, the connecting portion 53 is elastically deformed inward in the height direction starting from one end portion, so that the plug body 52 is separated from the liquid injection port 36. In this state, a nonaqueous electrolytic solution is injected into the case body 2 through the injection port 36.

  After injecting the non-aqueous electrolyte, the injection port 36 of the non-aqueous electrolyte secondary battery 1 is temporarily sealed with a plug 52 as shown in FIG. That is, the plug member 51 is pulled up toward the outside in the height direction via the operation unit 55. Then, the connecting portion 53 is elastically deformed from the one end portion toward the outside in the height direction, so that the plug body 52 approaches the liquid injection port 36. Then, by further pulling up the operation unit 55, the plug body 52 is fitted into the liquid injection port 36, and the liquid injection port 36 is closed from the inside of the nonaqueous electrolyte secondary battery 1.

  Next, the nonaqueous electrolyte secondary battery 1 is charged with the liquid injection port 36 temporarily sealed, and then aging is performed. Then, the gas generated from the electrode group 3 and the non-aqueous electrolyte fills the non-aqueous electrolyte secondary battery 1.

  After the aging is completed, the liquid injection port 36 is once opened, and the gas filled in the nonaqueous electrolyte secondary battery 1 is degassed. Specifically, the liquid injection port 36 is opened by pushing the plug member 51 inward in the height direction via the operation unit 55 as in the opening operation shown in FIG. When the liquid injection port 36 is opened, the gas filled in the nonaqueous electrolyte secondary battery 1 by aging is released to the outside through the liquid injection port 36.

  Then, after degassing, the liquid injection port 36 is closed again. Specifically, the liquid injection port 36 is closed by the plug body 52 by pulling up the plug member 51 toward the outside in the height direction via the operation unit 55 in the same manner as the closing operation described above.

Thereafter, as shown in FIG. 9, the operation portion 55 is broken from the plug body 52 through the thin portion 56.
Finally, as shown in FIG. 5, the liquid injection port 36 is finally sealed. Specifically, the liquid injection port 36 is fully sealed by joining the sealing plate 41 to the lid body 31 by laser welding or the like.
As described above, the above-described non-aqueous electrolyte secondary battery 1 is completed.

  Thus, in the present embodiment, the liquid injection port 36 can be temporarily sealed at the time of aging by the plug member 51 integrally connected to the insulating member 34. Thereby, for example, compared with the case where the liquid injection port 36 is temporarily sealed with a separate plug member, the production efficiency can be improved and the production cost can be reduced.

  Further, the plug member 51 closes the liquid injection port 36 from the inside of the nonaqueous electrolyte secondary battery 1 at the time of temporary sealing, so that the nonaqueous electrolyte due to the gas generated in the nonaqueous electrolyte secondary battery 1 at the time of aging. The increase in internal pressure of the secondary battery 1 acts in the closing direction of the plug body 52. Thereby, the liquid injection port 36 can be sealed more reliably, and for example, volatilization of the non-aqueous electrolyte and unexpected gas release can be suppressed during aging.

In addition, since the operation part 55 for opening and closing the plug member 51 is drawn to the outside of the nonaqueous electrolyte secondary battery 1 through the liquid injection port 36, the operability of the plug member 51 can be improved, and the production efficiency can be improved. Further improvement can be achieved.
Further, since the operation unit 55 is connected to the plug member 51 so as to be ruptured, the operation unit 55 can be removed from the lid 31 during the main sealing by breaking the operation unit 55 before the main sealing. It does not protrude outward. Therefore, the main sealing can be performed by the same method as before without being affected by the addition of the operation unit 55.

  In the above-described embodiment, the configuration in which the plug member 51 opens and closes the liquid injection port 36 from the inside of the nonaqueous electrolyte secondary battery 1 is described. However, the present invention is not limited to this, and the plug member 51 is a nonaqueous electrolyte secondary battery. 1 may be configured to open and close the liquid injection port 36 from the outside. For example, the insulating member 34 and the plug body 52 may be connected by the connecting portion 53 through the liquid injection port 36. In this case, the plug body 52 is formed in a size that can be inserted into the liquid injection port 36, and is drawn out of the nonaqueous electrolyte secondary battery 1 through the liquid injection port 36. In addition, in the plug body 52, an accommodating portion capable of accommodating the press-fitting member is formed. The press-fitting member can be formed integrally with the plug body 52.

  In such a configuration, when manufacturing the non-aqueous electrolyte secondary battery 1, the case body 2 is opened in a state where the plug body 52 is pulled out of the non-aqueous electrolyte secondary battery 1 and the liquid injection port 36 is opened. A non-aqueous electrolyte is injected into the inside. Thereafter, when the liquid injection port 36 is temporarily sealed, the plug body 52 is inserted into the liquid injection port 36 and the press-fitting member is pushed into the accommodating portion of the plug body 52. Then, when the press-fitting member is press-fitted into the housing portion, the plug body 52 is gradually expanded in diameter, and the outer peripheral surface of the plug body 52 is in close contact with the inner peripheral surface of the liquid injection port 36. Thereby, the liquid injection port 36 is temporarily sealed.

  Thereafter, when degassing is performed in the same manner as in the above-described embodiment, the press-fitting member is pulled up from the accommodating portion of the plug body 52. Then, the diameter of the plug body 52 is gradually reduced, and the outer peripheral surface of the plug body 52 is separated from the inner peripheral surface of the liquid injection port 36. Thereafter, the liquid injection port 36 is opened by pulling up the stopper 52. Thereby, similarly to the above-described embodiment, the gas filled in the nonaqueous electrolyte secondary battery 1 by aging is discharged to the outside through the liquid injection port 36.

Furthermore, although embodiment mentioned above demonstrated the structure by which the plug member 51 was continuously provided in the part located in the positive electrode terminal 32 side among the insulating members 34, it is not restricted to this. The design of the connecting portion of the insulating member 34 and the plug member 51 can be changed as appropriate.
Moreover, although the connection part 53 demonstrated the structure extended in linear form in embodiment mentioned above, you may extend in the shape of a curve.

In the above-described embodiment, the configuration in which the liquid injection port 36 is sealed again by the plug 52 after degassing and before the main sealing is described. However, the present invention is not limited to this. As long as the plug body 52 can be temporarily sealed at least during aging, it is not always necessary to close the liquid injection port 36 after degassing.
Further, in the above-described embodiment, the configuration in which the operation portion 55 is broken with respect to the plug body 52 after degassing has been described. That is, when the liquid injection port 36 can be opened and closed by the plug member 51 connected to the insulating member 34 at the time of aging, the plug body 52 is broken with respect to the connecting portion 53 during the main sealing. Alternatively, the plug member 51 may be broken with respect to the insulating member 34.

  According to at least one embodiment described above, the liquid injection port can be temporarily sealed at the time of aging by the plug member integrally connected to the insulating member. Thereby, compared with the case where a liquid injection port is temporarily sealed, for example with a separate plug member, improvement in manufacturing efficiency and reduction in manufacturing cost can be achieved.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Non-aqueous electrolyte secondary battery, 2 ... Case main body (exterior container), 3 ... Electrode group, 15 ... Positive electrode lead (lead), 16 ... Negative electrode lead (lead), 31 ... Lid body (exterior container), 32 ... Positive terminal (terminal), 33 ... Negative electrode terminal (terminal), 34 ... Insulating member, 36 ... Injection port, 51 ... Plug member, 55 ... Operation unit

Claims (3)

An outer container having a non-aqueous electrolyte injection port;
A group of electrodes housed in the outer container;
An electrode terminal attached to the outer container and exposed to the outside;
A lead connecting the electrode group and the electrode terminal in the outer container;
An insulating member disposed between the outer container and the lead,
The liquid injection port can be opened and closed by a plug member connected to the insulating member.
Non-aqueous electrolyte secondary battery. The plug member opens and closes the liquid injection port from the inside of the outer container.
The nonaqueous electrolyte secondary battery according to claim 1. In the plug member, an operation part drawn out toward the outside of the outer container through the liquid injection port is connected to the plug member so as to be breakable.
The nonaqueous electrolyte secondary battery according to claim 2.

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