JP2018137244A - Nonaqueous battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate lamination of separator or to improve lamination accuracy of the separator, while improving external-force tolerance of a battery separator, in a nonaqueous battery laminating a positive electrode plate, a negative electrode plate and a separator.SOLUTION: A square or rectangular separator 43 having four sides, by being cut in the parallel direction and the perpendicular direction to the MD direction, is formed. The sides 61a, 61b in the perpendicular direction to the MD direction are applied with heat, and the sides 62a, 62b in the parallel direction with the MD direction are not applied with heat. As a result, the sides 61a, 61b in the perpendicular direction to the MD direction are melted with heat to close a hole, and thereby external force resistance is improved thus restraining breakdown. The sides 62a, 62b not applied with heat become linear, and since alignment can be carried out with reference to the sides 62a, 62b, lamination of the separators 43 can be facilitated or lamination accuracy of the separators 43 can be improved.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a non-aqueous battery using a battery separator.

  Using a laminate film in which a synthetic resin layer is laminated on the surface of a metal layer as an exterior body, an electrode laminate formed by laminating a plurality of positive plates, negative plates and separators together with an electrolytic solution is formed into a flat shape. Aqueous batteries are known.

  The separator which comprises an electrode laminated body is what was formed by cut | disconnecting the microporous resin film comprised from polyolefin etc. is known.

JP 2006-287176 A

  However, the battery separator has high tensile strength in the unwinding direction (MD direction: Machine Direction), but low tensile strength in the TD (Transverse Direction) direction (perpendicular to the MD direction). That is, when the separator is mechanically cut in the TD direction, the side is easily torn.

  When this separator is stored in, for example, a battery, it means that the side is less resistant to external forces. A separator that has been torn by external force cannot sufficiently fulfill the role of an insulator, and the performance as a non-aqueous battery may be reduced.

  As described above, it is an object to provide a non-aqueous battery using a battery separator having excellent external force resistance.

  The present invention has been devised in view of the conventional problems, and one aspect thereof is a nonaqueous battery in which a positive electrode plate, a negative electrode plate, and a separator are laminated, and the separator is made of a microporous resin film. Cut in parallel and perpendicular to the MD direction and formed into a square or rectangle having four sides, the sides perpendicular to the MD direction are heated, and the sides parallel to the MD direction Is characterized in that no heat is applied.

  In a preferred embodiment, the side parallel to the MD direction is formed by mechanical cutting, and the side perpendicular to the MD direction is thermal cutting.

  In another preferred aspect, the side parallel to the MD direction is formed by mechanical cutting, and the side perpendicular to the MD direction is heated after cutting.

  In a preferred embodiment, heat is applied to the sides in the direction perpendicular to the MD direction until the sides become transparent.

Furthermore, in a preferred embodiment, a laminated electrode body as a power generation element is configured by laminating a plurality of separators, a positive electrode plate and a negative electrode plate, and the electrode laminated body is stored inside an exterior body made of a laminate film. Furthermore, in one preferable aspect, the positive electrode terminal connected to the positive electrode plate and the negative electrode terminal connected to the negative electrode plate are drawn out from one side of the exterior body, and the lead-out direction of the terminal is the same direction as the MD direction. It is characterized by.

  ADVANTAGE OF THE INVENTION According to this invention, in the non-aqueous battery using the battery separator, it becomes possible to facilitate the lamination of the battery separator or improve the lamination accuracy of the battery separator and improve the external force resistance of the battery separator.

It is a perspective view which shows the non-aqueous battery in embodiment. It is sectional drawing which shows the non-aqueous battery in embodiment. It is a schematic sectional drawing which shows the separator in embodiment.

  Hereinafter, an embodiment in a non-aqueous battery using a battery separator (hereinafter referred to as a separator) according to the present invention will be described in detail with reference to FIGS.

  In the following embodiments, the “electrode laminate” means a laminate in which a plurality of positive and negative electrode plates are laminated.

  Further, in the present invention, the "square or rectangular microporous resin film" includes not only those in which the shape when the microporous resin film is viewed from the thickness direction of the film is strictly square or rectangular, The shape when the microporous resin film is viewed from the thickness direction, such as when there is a convex or concave part at the end, there is a dimensional error, or there is a fine notch, is approximately square or rectangular including.

[Embodiment]
First, an example of the nonaqueous battery 1 according to the present invention will be described with reference to FIGS. 1 and 2. The nonaqueous battery 1 is, for example, a lithium ion secondary battery, and has a flat rectangular external shape as shown in FIG. 1 and a pair of positive electrodes made of conductive metal foil at one end in the longitudinal direction. Terminal 2 and negative electrode terminal 3 are provided.

  As shown in FIG. 2, the nonaqueous battery 1 is a battery in which an electrode laminate 4 as a power generation element having a rectangular shape is accommodated in an exterior body 5 made of a laminate film together with an electrolytic solution. The electrode laminate 4 includes a plurality of positive plates 41 and negative plates 42 that are alternately stacked with separators 43 interposed therebetween. For example, the three negative plates 42, the two positive plates 41, and the gap therebetween. The four separators 43 are included. That is, in this example, the negative electrode plates 42 are located on both surfaces of the electrode laminate 4. However, a configuration in which the positive electrode plate 41 is located on the outermost layer of the electrode laminate 4 is also possible. Note that the dimensions of each part in FIG. 2 are not necessarily accurate, but are exaggerated for the sake of explanation.

The positive electrode plate 41 is obtained by forming positive electrode active material layers 41b and 41c on both surfaces of a rectangular positive electrode current collector 41a. The positive electrode current collector 41a is made of an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil. The positive electrode active material layers 41b and 41c are formed of a positive electrode active material made of a lithium composite oxide such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), or lithium cobaltate (LiCoO ₂ ). The binder is mixed and applied to the main surface of the positive electrode current collector 41a.

  The negative electrode plate 42 is obtained by forming negative electrode active material layers 42b and 42c on both surfaces of a rectangular negative electrode current collector 42a. The negative electrode current collector 42a is made of, for example, an electrochemically stable metal foil such as nickel foil, copper foil, stainless steel foil, or iron foil. The negative electrode active material layers 42b and 42c are, for example, negative electrode active materials that occlude and release lithium ions of the positive electrode active material, such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. The binder is mixed and applied to the main surface of the negative electrode current collector 42a.

  A part of the longitudinal edge of the negative electrode current collector 42 a extends as an extended portion 42 d that does not include the negative electrode active material layers 42 b and 42 c, and the tip thereof is joined to the negative electrode terminal 3. Further, although not shown in FIG. 2, similarly, a part of the longitudinal edge of the positive electrode current collector 41a extends as an extension 41d that does not include the positive electrode active material layers 41b and 41c. The tip is joined to the positive terminal 2.

  Further, the electrolyte solution is not particularly limited, but for example, a non-aqueous electrolyte solution in which a lithium salt is dissolved in an organic solvent can be used as an electrolyte generally used in a lithium ion secondary battery. .

The exterior body 5 that houses the electrode laminate 4 configured as described above together with the electrolytic solution is composed of a heat fusion layer 51, a metal layer 52, and a protective layer 53, as shown in FIG. It consists of a laminate film having a layer structure. The intermediate metal layer 52 is made of, for example, an aluminum foil, and the heat-sealing layer 51 that covers the inner surface thereof is made of a synthetic resin that can be heat-fused, for example, polypropylene (PP), and is a protection that covers the outer surface of the metal layer 52. The layer 53 is made of a synthetic resin having excellent durability, such as polyethylene terephthalate (PET). A laminate film having a larger number of layers can also be used. In the above example, the synthetic resin layers (the heat-sealing layer 51 and the protective layer 53) are laminated on both surfaces of the metal layer 52. However, the synthetic resin layer (the protective layer 53) outside the metal layer 52 is not necessarily required. The exterior body 5 may be arranged on the lower surface side of the electrode laminate 4 in FIG. 2 in one example, and may be configured to have a synthetic resin layer (heat-sealing layer 51) only on the inner surface. The two sheets of the laminated film and the other laminated film arranged on the upper surface side are made into a two-sheet structure, and the four sides around the two laminated films are superposed and heat-sealed to each other. It has a configuration. The illustrated example shows such a two-layer exterior body 5. In another example, the outer package 5 is made of a single relatively large laminate film, and the electrode laminate 4 is arranged inside in a folded state, and the surrounding three sides are overlapped. And it is the structure which mutually heat-seal | fused.

  A pair of positive electrode terminal 2 and negative electrode terminal 3 positioned on the short side of the non-aqueous battery 1 having a rectangular shape are drawn out through the bonding surface of the laminate film when the laminate film is heat-sealed.

  The manufacturing procedure of the non-aqueous battery 1 is as follows. First, the negative electrode plate 42, the separator 43, the positive electrode plate 41, and the separator 43 are sequentially laminated, and the positive electrode current collector 41a and the extensions 41d and 42d of the negative electrode current collector 42a are spot welded to the positive electrode terminal 2 and the negative electrode terminal 3, respectively. The electrode laminate 4 is configured by attaching by, for example. Next, this electrode laminate 4 is covered with a laminate film to be the outer package 5, and the surrounding four sides (three sides in the case of the above-mentioned double fold) are heat-sealed leaving a relatively small filling port. Next, the exterior body 5 is filled with the electrolytic solution through the filling port, and then the filling port is heat-sealed to make the exterior body 5 sealed. Thereby, the nonaqueous battery 1 is completed.

  Here, the separator 43 will be described. The separator 43 has a function of preventing a short circuit between the positive electrode plate 41 and the negative electrode plate 42 and simultaneously holding an electrolyte, and is made of, for example, polyolefin such as polyethylene (PE) or polypropylene (PP). A microporous resin film. The separator 43 is not limited to a single-layer film such as polyolefin, but may be a three-layer structure in which a polypropylene film is sandwiched with a polyethylene film or the like, which dissolves when heat cutting or heat described below is applied.

  The separator 43 in the present embodiment is cut in a predetermined interval parallel to the MD direction and formed in a strip shape, and then cut in a predetermined interval perpendicular to the MD direction. As shown in FIG. 3, a rectangular or square separator 43 is formed.

  Here, as shown in FIG. 3, the cutting in the direction parallel to the MD direction is mechanical cutting. For example, a cutter or the like is used for this mechanical cutting. On the other hand, cutting in the direction perpendicular to the MD direction is thermal cutting. For example, a laser or the like is used for this thermal cutting, and the temperature is set to about 170 ° when the separator 43 is a polyolefin type.

  Thus, the side parts 62a and 62b become linear by making the cutting in the direction parallel to the MD direction mechanical cutting. As a result, when the electrode laminate 4 is laminated, the alignment can be performed with reference to the mechanically cut sides 62a and 62b, the electrode laminate 4 can be easily laminated, and the positive electrode and the positive electrode By improving the stacking accuracy of the negative electrode, it is possible to suppress a decrease in battery capacity due to stacking shift.

  Further, the cutting in the direction perpendicular to the MD direction is not mechanical cutting but thermal cutting, whereby the side portions 61a and 61b of the separator 43 are melted by heat to close the holes. Therefore, the resistance to the external force of the side portions 61a and 61b is improved, and damage to the side portions 61a and 61b can be suppressed. As a result, the separator 43 maintains a role as an insulator, and the non-aqueous battery 1 using the separator 43 can suppress a decrease in performance as a battery.

  Further, in the case of a winding type non-aqueous battery, since the cut side of the separator 43 is generally stopped with a tape, resistance to external force with respect to the cut side is not necessary. Therefore, when the separator 43 in the present embodiment is used for the nonaqueous battery 1 using the laminated electrode body 4, the effect becomes remarkable.

  Further, for example, when the positive electrode terminal 2 is drawn from the side portion 61a perpendicular to the MD direction and the negative electrode terminal 3 is drawn from the side portion 61b, the electrode laminate 4 is fixed on both sides. Movement of body 4 is restricted. However, in the present embodiment, since the positive electrode terminal 2 and the negative electrode terminal 3 are drawn out from the side portion 61a in one direction among the side portions 61a and 61b in the direction perpendicular to the MD direction, the electrode stack 4 has the side portion 61a. It is fixed only to the side exterior body 5. As a result, the electrode laminate 4 is restricted from moving in the direction of the side 61b in the exterior body 5, but is not restricted to move in the direction of the side 61a.

  Therefore, for example, when an external force is applied from the side portion 61b, the electrode laminate 4 moves in the direction of the side portion 61 in the exterior body 5, and the electrode laminate 4 comes into contact with the positive electrode terminal 2 and the negative electrode terminal 3, There is a possibility that the side part 61a of 43 may be damaged. However, in this embodiment, the side portion in the direction perpendicular to the stretching direction, particularly 61a, is improved in resistance to external force by being thermally cut, and thus is damaged by contact with the positive electrode terminal 2 and the negative electrode terminal 3. It is suppressed. As a result, the separator 43 can maintain the role as an insulator and suppress the performance deterioration of the nonaqueous battery 1.

  Regarding the sides 61a and 61b perpendicular to the MD direction in the embodiment, the method of applying heat when cutting the sides has been described, but heat may be applied after cutting. Alternatively, the separator 43 may be laminated with the MD direction aligned, and heat may be applied to a side perpendicular to the MD direction with a heater or the like with respect to the laminated electrode laminate 4. Further, before cutting, heat may be applied to a cutting portion in a direction perpendicular to the MD direction of the separator 43, and the cutting may be performed after applying heat. Moreover, when applying heat, it is good to carry out to such an extent that the edge | side perpendicular | vertical to MD direction becomes transparent. By applying heat to such an extent that it becomes transparent, it is sufficiently melted and resistance to external force is improved.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... Non-aqueous battery 2 ... Positive electrode terminal 3 ... Negative electrode terminal 4 ... Laminated electrode body 5 ... Exterior body 41 ... Positive electrode plate 42 ... Negative electrode plate 43 ... Battery separator 61a, 61b, 62a, 62b ... Side part

Claims (3)

A non-aqueous battery having an electrode laminate in which a plurality of positive plates, a plurality of negative plates and a plurality of separators are laminated,
The plurality of separators are formed in a square or rectangle having four sides cut in a direction parallel to and perpendicular to the MD direction of the microporous resin film,
Sides perpendicular to the MD direction are formed by applying heat when cutting, and sides parallel to the MD direction are not heated.
The electrode laminate is formed by laminating the plurality of positive plates, the plurality of negative plates, and the plurality of separators in a state where the separators are not heat-sealed in any of the four sides.
The positive electrode plate has a positive electrode current collector and a positive electrode active material layer, and a part of the longitudinal edge of the positive electrode current collector is a positive electrode current collector extension portion that does not include the positive electrode active material layer. The negative electrode plate has a negative electrode current collector and a negative electrode active material layer, and a part of the longitudinal edge of the negative electrode current collector is a negative electrode active material layer. As a negative electrode current collector extension portion not including a negative electrode active material layer, the negative electrode active material layer extends in the same direction as the MD direction, and is connected to the positive electrode current collector extension portion and the negative electrode current collector extension portion. The non-aqueous battery is characterized in that the negative electrode terminal is drawn out from one side of the exterior body, and the longitudinal direction of the positive electrode current collector, the negative electrode current collector, and the lead-out direction of both terminals are the same as the MD direction.   The nonaqueous battery according to claim 1, wherein heat is applied to a side perpendicular to the MD direction until the side becomes transparent.   The non-aqueous battery according to claim 1 or 2, wherein the outer package is a laminate film, and the positive electrode terminal and the negative electrode terminal protrude from a side where the laminate films are heat sealed.

Images