JP2012069360A - Lamination type battery and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lamination type battery and a manufacturing method of the lamination type battery that relate to a manufacturing technology of the lamination type battery and desirably prevents the occurence of internal short circuit caused by displacement of a positive electrode and a negative electrode.SOLUTION: In a lamination type battery 10, a first separator 60 and a second separator 70 formed into a fanfold shape are laminated so as to be overlapped each other between a positive electrode 40 and a negative electrode 50, and the first separator and the second separator are arranged so as to be orthogonal to each other viewed from the lamination direction.

Description

  The present invention relates to a stacked battery and a method for manufacturing a stacked battery.

  In recent years, the development of electric vehicles (EV), hybrid electric vehicles (HEV), and fuel cell vehicles (FCV) has been promoted against the background of the increasing environmental protection movement. As a power source for driving these motors, a multilayer battery that can be repeatedly charged and discharged has attracted attention. In a stacked battery, generally, a positive electrode in which a positive electrode active material is applied on both sides of a positive electrode current collector and a negative electrode in which a negative electrode active material is applied on both sides of a negative electrode current collector include an electrolyte (separation membrane). It has a structure which is connected via a battery and is housed in a battery case.

  In the method for manufacturing a bipolar battery described in Patent Document 1, in order to prevent displacement of the positive electrode and the negative electrode, the positive electrode plate forming the positive electrode current collector and the negative electrode plate forming the negative electrode current collector are formed into a separator by an adhesive. The technology to fix is adopted. By suppressing the displacement between the positive electrode and the negative electrode, the occurrence of an internal short circuit due to the contact between the positive electrode and the negative electrode is prevented.

JP 2001-229979 A

  However, when the adhesive strength of the adhesive is weakened due to secular change or the like, the positive electrode and the negative electrode may be displaced and an internal short circuit may occur. Therefore, it is required for the stacked battery to provide a measure that can prevent the occurrence of an internal short circuit at the time of misalignment, in addition to the measure for preventing the misalignment of the positive electrode and the negative electrode.

  The present invention relates to a manufacturing technique of a stacked battery, and an object thereof is to provide a stacked battery that suitably prevents the occurrence of an internal short circuit that can occur in association with the misalignment of a positive electrode and a negative electrode, and a method for manufacturing the stacked battery. Yes.

  In the multilayer battery according to the present invention, the first and second separators formed in a twisted manner are stacked so as to overlap each other between the positive electrode and the negative electrode. Further, the first and second separators are arranged orthogonal to each other when viewed from the stacking direction.

  According to the present invention, two separators formed in a twisted manner are stacked and stacked in a direction orthogonal to each other, thereby restricting the moving direction of the positive electrode and the negative electrode and moving the positive electrode and the negative electrode closer to each other. This can be prevented. Thereby, generation | occurrence | production of the internal short circuit accompanying the position shift of a positive electrode and a negative electrode can be prevented suitably.

1A and 1B are external views of a stacked battery according to an embodiment, where FIG. 1A is a plan view and FIG. 1B is a perspective view. FIG. 2 is a partial cross-sectional view of the stacked battery as viewed from the arrow 2A side in FIG. It is sectional drawing which follows the arrow 3A-3A line | wire of FIG. 1 (A). It is sectional drawing which follows the arrow 4A-4A line | wire of FIG. 1 (A). It is a conceptual diagram for demonstrating the direction which overlaps a separator. 6A and 6B are cross-sectional views for explaining the operation of the stacked battery according to the embodiment. FIG. 6A is a cross-sectional view taken along the line 6A-6A in FIG. 3 and FIG. It is sectional drawing which follows a 6B-6B line. It is a figure which shows the laminated battery which concerns on a modification, and is partial sectional drawing seen from the arrow 2A side of FIG. 1 (A). It is a figure which shows the laminated battery which concerns on a modification, and is sectional drawing which follows the arrow 3A-3A line | wire of FIG. 1 (A). It is a figure which shows the laminated battery which concerns on a modification, and is sectional drawing which follows the arrow 4A-4A line | wire of FIG. 1 (A).

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  First, the overall structure of the stacked battery according to the embodiment will be described.

  Referring to FIGS. 1A and 1B, a stacked battery 10 configured as a lithium ion secondary battery seals a substantially rectangular power generation element 20 in which a charge / discharge reaction proceeds inside an exterior body 90. It has the structure made to do.

  Referring to FIG. 3, the power generation element 20 includes a positive electrode 40 in which a positive electrode active material layer 43 is formed on a positive electrode current collector 41, and two separators 60 and 70 that form part of an electrolyte layer (not shown). The negative electrode current collector 51 is laminated with a negative electrode 50 having a negative electrode active material layer 53 formed thereon. More specifically, one positive electrode active material layer 43 and one negative electrode active material layer 53 adjacent thereto are arranged so as to face each other with separators 60 and 70 therebetween. The positive electrode 40 and the negative electrode 50 are fixed to the separators 60 and 70 by a known adhesive used for batteries. For easy understanding, a spatial gap is illustrated between the constituent members, but this gap can be omitted as appropriate.

  One unit cell layer 30 is configured by the two separators 60 and 70 and the positive electrode active material layer 43 and the negative electrode active material layer 53 laminated so as to sandwich the two separators 60 and 70 therebetween. The power generation element 20 is configured by electrically connecting the plurality of unit cell layers 30.

  The positive electrode current collector 41 and the negative electrode current collector 51 are provided with a current collector plate 80 for taking out the generated electricity to the outside. The current collector plate 80 is sandwiched by the exterior body 90 so that one end of the current collector plate 90 is led out to the outside.

  Next, each component of the stacked battery will be described.

  As the positive electrode current collector 41 and the negative electrode current collector 51, any member conventionally used as a current collector material for a battery can be appropriately employed. As an example, examples of the positive electrode current collector and the negative electrode current collector include aluminum, nickel, iron, stainless steel (SUS), titanium, and copper. Among these, from the viewpoints of electron conductivity and battery operating potential, aluminum is preferable as the positive electrode current collector, and copper is preferable as the negative electrode current collector.

The positive electrode active material layer 43 includes a positive electrode active material, and if necessary, a conductive additive, a binder, an electrolyte (polymer matrix, ion conductive polymer, electrolytic solution, etc.) for increasing electrical conductivity, and ion conductivity. Electrolyte support salt (lithium salt) and the like. The positive electrode active material is not particularly limited as long as it is a material that can occlude and release lithium, for example, and a positive electrode active material usually used in lithium ion secondary batteries can be used. The positive electrode active material is preferably a lithium-transition metal composite oxide, a Li—Mn composite oxide such as LiMn ₂ O _4, a Li—Ni composite oxide such as LiNiO ₂ , or a Li—Co composite such as LiCoO _2. Examples thereof include oxides and Li—Fe-based composite oxides such as LiFePO ₄ .

The negative electrode active material layer 53 includes a negative electrode active material, and if necessary, a conductive additive, binder, electrolyte (polymer matrix, ion conductive polymer, electrolyte solution, etc.) for increasing electrical conductivity, and ion conductivity are increased. Electrolyte support salt (lithium salt) and the like. The negative electrode active material is not particularly limited as long as it is a material that can occlude and release lithium, for example, and a negative electrode active material usually used in lithium ion secondary batteries can be used. Examples of the negative electrode active material include metals such as Si and Sn, or metal oxides such as TiO, Ti ₂ O ₃ , TiO ₂ , SiO ₂ , SiO, and SnO ₂ , Li _4/3 Ti _5/3 O _4. Or a composite oxide of lithium and transition metal such as Li ₇ MnN, Li—Pb alloy, Li—Al alloy, Li, or graphite, carbon black, activated carbon, carbon fiber, coke, soft carbon, hard carbon, etc. And carbon materials.

  The electrolyte layer functions as a spatial partition (spacer) between the positive electrode active material layer 43 and the negative electrode active material layer 53. In addition, it also has a function of holding an electrolyte that is a lithium ion transfer medium between the positive electrode 40 and the negative electrode 50 during charge and discharge. There is no restriction | limiting in particular in the electrolyte which comprises an electrolyte layer, Polymer electrolytes, such as a liquid electrolyte, a polymer gel electrolyte, and a polymer solid electrolyte, can be used suitably.

  As the separator, a porous sheet separator made of a polymer that absorbs or holds an electrolyte is used. Two separators of a first separator 60 and a second separator 70 made of polyethylene (PE) are prepared. As the separator, other porous sheet separators, nonwoven fabric separators, and the like can be used. Examples of the porous sheet separator include a polyolefin microporous film such as polypropylene, a laminate having a three-layer structure of PP / PE / PP, polyethylene terephthalate (PET), and polyimide. As the material of the nonwoven fabric separator, for example, a conventionally known material such as rayon, acetate, nylon, polyester, polyolefin such as polypropylene or polyethylene, polyimide, or aramid resin can be used.

  As shown in FIG. 5, each separator 60, 70 is formed in a twisted shape by bending a plurality of separator materials as a material prepared in a strip shape. The first separator 60 includes a flat plate portion 61 on which the positive electrode 40 and the negative electrode 50 are laminated, a vertical wall-shaped first bent portion 63 and a second bent portion 65 that regulate the moving direction of the positive electrode 40 and the negative electrode 50. Have. Similarly to the first separator 60, the second separator 70 also has a flat plate portion 71 on which the positive electrode 40 and the negative electrode 50 are stacked, and a vertical wall-shaped first bent portion for regulating the moving direction of the positive electrode 40 and the negative electrode 50. 73 and a second bent portion 75. In the description of the specification, the twisted shape means a shape in which a bent portion and a flat plate portion connected to the bent portion are continuous in a stacking direction.

  As shown in FIG. 3, two separators, a first separator 60 and a second separator 70, are stacked between the adjacent positive electrode 40 and negative electrode 50. For this reason, in consideration of the permeability of the electrolytic solution and the gas discharge property, for example, it is preferable to prepare separators 60 and 70 having a thickness about half that of a normal separator.

  If the current collector is processed in a twisted shape, an internal short circuit may occur due to powder falling off of the electrode. For this reason, it is necessary to take measures such as uncoating the folded portion, and there is a risk of forming a useless space that does not contribute to power generation. In the stacked battery 10, a known type formed in a rectangular shape is used for the positive electrode 40 on which the positive electrode active material layer 43 is formed and the negative electrode 50 on which the negative electrode active material layer 53 is formed. It is possible to do this, and there is no need to prepare a twisted one. There is no risk of powder falling during the production of the positive electrode 40 and the negative electrode 50 and the occurrence of an internal short circuit due to powder falling, and there is no need to form an uncoated portion on the electrode. Therefore, a useless space that does not contribute to power generation is not formed in the positive electrode 40 and the negative electrode 50.

  The separators 60 and 70 can be prepared in a twisted shape in advance, or can be prepared in a twisted shape after manufacturing.

  For the current collector plate 80, for example, a highly conductive member such as aluminum, copper, titanium, nickel, stainless steel, or an alloy thereof can be used.

  The exterior body 90 is a sheet such as a polymer-metal composite laminate film in which a metal (including an alloy) such as aluminum, stainless steel, nickel, or copper is covered with an insulator such as a polypropylene film from the viewpoint of weight reduction and thermal conductivity. A material made of materials can be used. The exterior body 90 is sealed by joining a part of the outer periphery of the sheet material by thermal fusion, and the power generation element 20 is accommodated inside the exterior body 90.

  Next, a stacked form of the stacked battery according to the embodiment will be described.

  As shown in FIGS. 2 to 5, the separators 60 and 70 are stacked such that the flat plate portions 61 and 71 overlap each other between the stacked positive electrode 40 and negative electrode 50. In addition, the direction in which the flat plate portion 61 of the first separator 60 extends to the first bent portion 63 and the second bent portion 65 (the direction of the arrow aa ′ in FIG. 5), and the flat plate portion 71 of the second separator 70. The separator extends so that the direction (arrow bb ′ direction in FIG. 5) extending to the first bent portion 73 and the second bent portion 75 is orthogonal to each other when viewed from the stacking direction (arrow A direction in FIG. 5). Is placed. More specifically, the separators 60 and 70 are stacked and laminated so that the first bent portion 73 of the second separator 70 is positioned between the adjacent flat plate portions 61 of the first separator 60 ( (See FIG. 4).

  As shown in FIG. 6 (A), the first bent portion 63 of the first separator 60 and the first bent portion 73 of the second separator 70 do not face each other and each It arrange | positions so that two adjacent sides of the positive electrode 40 may be enclosed by the one bending parts 63 and 73. FIG. The stacked positive electrode 40 is restricted from moving in the right direction in the drawing by the first bent portion 63 of the first separator 60. Further, the movement of the positive electrode 40 in the downward direction in the figure is restricted by the first bent portion 73 of the second separator 70.

  As shown in FIG. 6B, the second bent portion 65 of the first separator 60 and the second bent portion 75 of the second separator 70 are arranged so that they do not overlap each other. The second bent portions 65 and 75 are arranged so that two adjacent sides of the negative electrode 50 are surrounded. The laminated negative electrode 50 is restricted from moving leftward in the figure by the second bent portion 65 of the first separator 60. Further, the movement of the negative electrode 50 in the upward direction in the figure is restricted by the second bent portion 75 of the second separator 70.

  Thus, according to the multilayer battery 10 according to the embodiment, the moving directions of the positive electrode 40 and the negative electrode 50 are obtained by stacking the two separators 60 and 70 formed in a twisted manner in a direction orthogonal to each other. It is possible to prevent the positive electrode 40 and the negative electrode 50 from moving toward each other. As a result, even when the positive electrode 40 and the negative electrode 50 are misaligned, it is possible to prevent the occurrence of an internal short circuit by preventing contact between the positive electrode 40 and the negative electrode 50 due to the misalignment.

  Further, the movement direction of the positive electrode 40 and the negative electrode 50 can be regulated while stably holding the positive electrode 40 and the negative electrode 50 in the flat plate portion 61 of the first separator 60 and the flat plate portion 71 of the second separator 70. .

  Here, for example, it is considered that the electrode plate itself can be prevented from being displaced by storing the electrode plate in a bag-shaped separator and folding the electrode plate a plurality of times. It is done. However, since the operation | work which accommodates an electrode plate in the separator processed into the bag shape and the operation | work which folds an electrode plate with a separator are needed, a manufacture operation becomes complicated. In the laminated battery 10, since the occurrence of an internal short circuit is prevented by a simple operation in which the positive electrode 40, the negative electrode 50, and the two separators 60 and 70 formed in a twisted manner are stacked and stacked, The complication of the manufacturing work associated with the short-circuit prevention measures can be suppressed.

(Modification)
Next, a modification of the above-described embodiment will be described. In the description, the same members as those in the above-described embodiment are denoted by the same reference numerals, and a part of the description is omitted.

  As shown in FIGS. 7 to 9, in the modification, the flat plate portion 71 of the second separator 70 and the positive electrode 40 or the negative electrode 50 are positioned between the adjacent flat plate portions 61 of the first separator 60. Thus, the first separator 60 and the second separator 70 are laminated. Similarly to the above-described embodiment, the separators 60 and 70 are laminated so that the flat plate portions 61 and 71 overlap each other between the laminated positive electrode 40 and negative electrode 50. The flat plate portion 61 of the first separator 60 extends in the first bent portion 63 and the second bent portion 65, and the flat plate portion 71 of the second separator 70 is connected to the first bent portion 73 and the second bent portion 73. The separators 60 and 70 are arranged so that the direction extending to the bent portion 75 is orthogonal to each other when viewed from the stacking direction.

  By adopting the laminated form shown in the modification, the moving direction of the positive electrode 40 and the negative electrode 50 is regulated by the two separators 60 and 70 laminated in the same manner as in the above-described embodiment, and the positive electrode 40 and the negative electrode 50 approach each other. Can be prevented. Thereby, generation | occurrence | production of the internal short circuit accompanying the position shift of the positive electrode 40 and the negative electrode 50 can be prevented suitably.

  The number of times the separator is folded, the angle at which the separator is folded, and the like can be changed as appropriate, and are not particularly limited to those shown in the embodiment. For example, it is possible to use a folded separator in which the bent portion is bent at a right angle with respect to the flat plate portion.

10 stacked battery,
20 power generation elements,
30 cell layer,
40 positive electrode,
41 positive electrode current collector,
43 positive electrode active material layer,
50 negative electrode,
51 negative electrode current collector,
53 negative electrode active material layer,
60 first separator,
61 flat plate part,
63 1st bending part (bending part),
65 2nd bending part (bending part),
70 second separator,
71 flat plate part,
73 1st bending part (bending part),
75 2nd bending part (bending part),
80 current collector,
90 exterior body.

Claims (3)

  The first and second separators formed in a twisted manner are stacked so as to overlap each other between the positive electrode and the negative electrode, and the first and second separators are orthogonal to each other when viewed from the stacking direction. A laminated battery characterized by being arranged. The twisted shape has a shape in which a bent portion obtained by bending a strip-shaped separator material and a flat plate portion connected to the bent portion are repeated,
The flat plate portion of the first separator and the flat plate portion of the second separator are laminated so as to overlap each other, and the flat plate portion of the first separator extends in the bent portion of the first separator, and 2. The stacked battery according to claim 1, wherein the flat plate portion of the second separator is disposed so that a direction in which the flat plate portion of the second separator extends to the bent portion of the second separator is orthogonal to each other when viewed from the stacking direction.   A multilayer battery comprising a step of laminating first and second separators formed in a twisted manner so as to overlap each other between a positive electrode and a negative electrode and so as to be orthogonal to each other when viewed from the laminating direction. Production method.

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