JP2018060699A - Manufacturing method for laminated secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a manufacturing method for a laminated secondary battery having excellent short-circuit prevention and volume energy density.SOLUTION: A manufacturing method for a laminated secondary battery configured by laminating a positive electrode and negative electrode, the positive electrode including a positive electrode terminal part and positive electrode lamination part, the negative electrode including a negative electrode terminal part and negative electrode lamination part, the positive electrode lamination part and negative electrode lamination part having different sizes, the positive electrode or negative electrode having a separator formed thereon, the positive electrode terminal part and negative electrode terminal part being formed at different positions when viewed from the lamination direction, includes: a process for setting a lamination jig having a lamination jig recess; a process for setting an upper surface direction or side surface direction of the positive electrode terminal part or negative electrode terminal part of the positive electrode or negative electrode on which the separator is formed, so as to fit the lamination jig recess; and a process for laminating the positive electrode and negative electrode to manufacture the laminated secondary battery.SELECTED DRAWING: Figure 3

Description

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

  Examples of the shape of a secondary battery used in a battery car or the like include a wound cylindrical type, a wound square type, and a stacked type. As a technique related to the stacked secondary battery, for example, Patent Document 1 discloses the following technique. A positive electrode positioning member 40 and a negative electrode positioning member 50 were provided in the case of the secondary battery. The positive electrode positioning member 40 and the negative electrode positioning member 50 have a pair of support portions 41 and 51 disposed on both sides of the tab portions 12f and 13f in the extending direction of the sides 121e and 131e of the metal sheets 121 and 131. Yes. Then, the contact portions 42 and 52 having shapes that are in contact with the outer edge portions of the tab portions 12f and 13f and conform to the outer edge portions of the tab portions 12f and 13f are formed on the pair of support portions 41 and 51. Patent Document 2 discloses the following technique. In the electrode assembly 14 of the secondary battery 10, the positive electrode current collecting tab 31 and the negative electrode current collecting tab 32 are respectively laminated on the electrode assembly 14, and the outermost positive electrode current collecting tab 31 and negative electrode current collecting member in the stacking direction. A positive electrode conductive member 35 and a negative electrode conductive member 36 are welded to the tab 32. Through-holes penetrating in the stacking direction on the tip side from the positions where the conductive members 35 and 36 are electrically connected to all the stacked positive electrode current collecting tabs 31 and all the stacked negative electrode current collecting tabs 32 31a and 32a are formed.

JP 2013-187141 A

  In Patent Document 1, in addition to the positive electrode plate 12 and the negative electrode plate 13, one edge portion 141 of the separator 14 is replaced with a pair of third contact portions 42 c of the positive electrode positioning member 40 and a pair of third electrodes of the negative electrode positioning member 50. Since the separator 14 is positioned at a predetermined position with respect to the positive electrode plate 12 and the negative electrode plate 13 in contact with the contact portion 42c, there is a possibility that a short circuit occurs due to the displacement of the electrode plate.

  On the other hand, in Patent Document 2, the separator 23 is formed in a bag shape, and the positive electrode sheet 21 is accommodated in the separator 23 in a state where the positive electrode current collecting tab 31 protrudes from the upper portion of the bag. Although the sheet 21 is not displaced in the direction along the surface of the positive electrode sheet 21 with respect to the separator 23, the size of the electrode current collecting tab is adjusted because the position of the electrode is adjusted using the through hole. May increase and the volumetric energy density may decrease.

  An object of the present invention is to prevent a short circuit and to improve volume energy density of a stacked secondary battery.

  The features of the present invention for solving the above problems are as follows, for example.

  A method for manufacturing a laminated secondary battery in which a positive electrode and a negative electrode are laminated, wherein the positive electrode has a positive electrode terminal portion and a positive electrode laminate portion, the negative electrode has a negative electrode terminal portion and a negative electrode laminate portion, The size of the positive electrode laminate portion and the negative electrode laminate portion is different, and a separator is formed on the positive electrode or the negative electrode. When viewed from the lamination direction, the positive electrode terminal portion and the negative electrode terminal portion are formed at different positions. A step of setting a laminated jig having a separator, a step of setting the positive electrode terminal portion or the negative electrode terminal portion of the positive electrode or negative electrode on which the separator is formed in accordance with the indentation for the laminated jig, and the positive electrode and the negative electrode are laminated. And a step of producing a laminated secondary battery, and a method for producing a laminated secondary battery.

  According to the present invention, it is possible to improve short-circuit prevention and volume energy density of a stacked secondary battery. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a plane schematic diagram which shows an example of the laminated type secondary battery which concerns on one Embodiment of this invention. FIG. 2 is a cross-sectional structure diagram of the A-A ′ plane of FIG. 1. It is a plane schematic diagram which shows the lamination | stacking procedure using the jig | tool of the laminated type secondary battery concerning one Embodiment of this invention. It is a plane schematic diagram which shows the notch shape of the terminal part concerning one Embodiment of this invention. It is a plane schematic diagram which shows an example of the laminated type secondary battery concerning one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various modifications by those skilled in the art are within the scope of the technical idea disclosed in this specification. Changes and modifications are possible. In all the drawings for explaining the present invention, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

  In the present invention, embodiments of the structure of a lithium ion secondary battery will be mainly described. However, the present invention is not limited to a lithium ion secondary battery, but a nickel hydrogen battery, a nickel cadmium battery, a lead battery, a lithium ion battery, a sodium ion battery, or the like. Any secondary battery or primary battery can be used as long as it uses a solid electrolyte.

  FIG. 1 is a schematic plan view showing an example of a stacked secondary battery according to an embodiment of the present invention. FIG. 2 is a cross-sectional structural view taken along the plane A-A ′ of FIG. 1, and is a schematic cross-sectional view illustrating an example of a stacked secondary battery according to an embodiment of the present invention. The upper surface direction and the side surface direction are defined as shown in FIG. The stacking direction and the in-plane direction are defined as shown in FIG.

  In FIG. 1, the stacked secondary battery 10 includes a positive electrode 101 and a negative electrode 201. The positive electrode 101 has a positive electrode laminate portion 102 and a positive electrode terminal portion 103, and the negative electrode 201 has a negative electrode laminate portion 202 and a negative electrode terminal portion 203. The positive electrode 101 and the negative electrode 201 may be referred to as electrodes, the positive electrode laminate portion 102 and the negative electrode laminate portion 202 may be referred to as electrode laminate portions, and the positive electrode terminal portion 103 and the negative electrode terminal portion 203 may be referred to as electrode terminal portions. When viewed from the stacking direction, the positive terminal portion 103 and the negative terminal portion 203 are formed at different positions when viewed from the stacking direction. An electrode terminal portion is formed in the upper surface direction of the electrode laminated portion.

In FIG. 1, the sizes of the positive electrode 101 and the negative electrode 201 are different. Specifically, the positive electrode laminate 102 and the negative electrode laminate 202 are different in size. In the in-plane direction of the stacked secondary battery 10, the negative electrode stacking portion 202 is made larger than the positive electrode stacking portion 102, but may be made smaller. By making the negative electrode laminate portion 202 larger than the positive electrode laminate portion 102, lithium deposition from the positive electrode active material in the positive electrode 101 can be suppressed. Moreover, although the positive electrode 101 and the negative electrode 201 are each one sheet, you may laminate | stack an electrode, combining an electrode terminal part for every plurality.
In FIG. 2, the positive electrode 101 and the negative electrode 201 are illustrated as being spatially separated, but in an actual battery, there is almost no space between them, and they are in contact in a plane. In FIG. 2, the positive electrode 101 includes a positive electrode current collector foil 104, a positive electrode mixture layer 105, and a positive electrode separator 106. The negative electrode 201 includes a negative electrode current collector foil 204, a negative electrode mixture layer 205, and a negative electrode separator 206. The positive electrode current collector foil 104 and the negative electrode current collector foil 204 may be referred to as an electrode current collector foil, the positive electrode mixture layer 105 and the negative electrode mixture layer 205 may be referred to as an electrode mixture layer, and the positive electrode separator 106 and the negative electrode separator 206 may be referred to as separators. Each of the positive electrode 101 and the negative electrode 201 has the positive electrode separator 106 and the negative electrode separator 206, but only one of them may have a separator. In FIG. 2, the size of the positive electrode separator 106 and the size of the positive electrode mixture layer 105, the size of the negative electrode separator 206, and the size of the negative electrode mixture layer 205 are the same, but they may not be the same. When producing a separator by application | coating, both magnitude | sizes may become the same. In FIG. 2, in the stacking direction, two sets of the positive electrode 101 and the negative electrode 201 are stacked in this order, but may be one set or three or more sets.

  A positive electrode mixture layer 105 and a positive electrode separator 106 are formed on both surfaces of the positive electrode current collector foil 104 excluding the lowermost part in the stacking direction. A negative electrode mixture layer 205 and a negative electrode separator 206 are formed on both surfaces of the negative electrode current collector foil 204 excluding the lowermost part in the stacking direction.

  In the lowermost positive electrode 101 in the stacking direction, the positive electrode mixture layer 105 and the positive electrode separator 106 are formed only on one surface of the positive electrode current collector foil 104 (the surface on which the negative electrode 201 is disposed). In the uppermost negative electrode 201 in the stacking direction, the negative electrode mixture layer 205 and the negative electrode separator 206 are formed only on one surface of the negative electrode current collector foil 204 (the surface on which the positive electrode 101 is disposed).

  The unit cell 20 includes a positive electrode current collector foil 104, a positive electrode composite material layer 105, a positive electrode separator 106, a negative electrode separator 206, a negative electrode composite material layer 205, and a negative electrode current collector foil 204. Further, the unit cells 20 are arranged while repeating bust image inversion in the stacking direction. In this embodiment, it is composed of three sets of unit cells.

  The auxiliary line 800 is a boundary between the electrode laminated portion and the electrode terminal portion. The positive electrode stacking unit 102 includes a positive electrode current collector foil 104, a positive electrode mixture layer 105, and a positive electrode separator 106. The positive electrode terminal portion 103 is also configured by the positive electrode current collector foil 104, the positive electrode mixture layer 105, and the positive electrode separator 106, but may be configured by only the positive electrode current collector foil 104. Even when the positive electrode terminal portion 103 is constituted by the positive electrode current collector foil 104, the positive electrode mixture layer 105, and the positive electrode separator 106, the positive electrode terminal portion 103 is disposed on the positive electrode current collector foil 104 for connection with an external connection terminal. There are places where the positive electrode mixture layer 105 and the positive electrode separator 106 are not formed.

  The negative electrode laminate 202 is composed of a negative electrode current collector foil 204, a negative electrode mixture layer 205, and a negative electrode separator 206. The negative electrode terminal portion 203 is also composed of the negative electrode current collector foil 204, the negative electrode mixture layer 205, and the negative electrode separator 206, but may be composed of only the negative electrode current collector foil 204. Even when the negative electrode terminal portion 203 includes the negative electrode current collector foil 204, the negative electrode mixture layer 205, and the negative electrode separator 206, the negative electrode terminal portion 203 is disposed on the negative electrode current collector foil 204 for connection with an external connection terminal. There is a portion where the negative electrode mixture layer 205 and the negative electrode separator 206 are not formed.

<Positive electrode current collector foil 104>
As the positive electrode current collector foil 104, an aluminum foil, an aluminum perforated foil having a pore diameter of 0.1 to 10 mm, an expanded metal, a foamed aluminum plate, or the like is used. As the material, stainless steel, titanium, or the like can be applied in addition to aluminum. The thickness of the positive electrode current collector foil 104 is preferably 10 nm to 1 mm. About 1-100 micrometers is desirable from a viewpoint of the energy density of a secondary battery and the mechanical strength of an electrode.

<Positive electrode mixture layer 105>
The positive electrode mixture layer 105 contains at least a positive electrode active material capable of inserting and extracting Li. Examples of the positive electrode active material include LiCo composite oxides, LiNi composite oxides, LiMn composite oxides, Li—Co—Ni—Mn composite oxides, LiFeP composite oxides, and the like. In the positive electrode mixture layer 105, a conductive material responsible for electronic conductivity in the positive electrode mixture layer 105, a binder that secures adhesion between the materials in the positive electrode mixture layer 105, and further in the positive electrode mixture layer 105 A solid electrolyte for ensuring ionic conductivity may be included.

  As a method for producing the positive electrode mixture layer 105, a material contained in the positive electrode mixture layer 105 is dissolved in a solvent to form a slurry, which is applied onto the positive electrode current collector foil 104. The coating method is not particularly limited, and for example, a conventional method such as a doctor blade method, a dipping method, or a spray method can be used. Further, a plurality of positive electrode mixture layers 105 may be laminated on the positive electrode current collector foil 104 by performing a plurality of times from application to drying. Thereafter, the positive electrode mixture layer 105 is formed through a drying process for removing the solvent and a pressing step for ensuring electron conductivity and ion conductivity in the positive electrode mixture layer 105.

  The thickness of the positive electrode mixture layer 105 is designed according to the energy density, rate characteristics, and input / output characteristics of the all-solid-state battery, but generally has a size of several μm to several hundred μm. The particle size of a material such as a positive electrode active material included in the positive electrode mixture layer 105 is defined to be equal to or less than the thickness of the positive electrode mixture layer 105. When the positive electrode active material powder includes coarse particles having a particle size equal to or larger than the thickness of the positive electrode mixture layer 105, the coarse particles are previously removed by sieving classification, wind classification, etc. Prepare the particles.

<Negative electrode current collector foil 204>
For the negative electrode current collector foil 204, a copper foil, a copper perforated foil having a hole diameter of 0.1 to 10 mm, an expanded metal, a foamed copper plate, or the like is used. In addition to copper, stainless steel, titanium, nickel, or the like can be applied. The thickness of the negative electrode current collector foil 204 is preferably 10 nm to 1 mm. About 1-100 micrometers is desirable from a viewpoint of the energy density of an all-solid-state battery and the mechanical strength of an electrode.

<Negative electrode mixture layer 205>
The negative electrode mixture layer 205 contains at least a negative electrode active material capable of inserting and extracting Li. Examples of the negative electrode active material include carbon-based materials such as natural graphite, soft carbon, and amorphous carbon, Si metal, Si alloy, lithium titanate, and lithium metal. In the negative electrode mixture layer 205, a conductive material responsible for electronic conductivity in the negative electrode mixture layer 205, a binder that ensures adhesion between the materials in the negative electrode mixture layer 205, and further in the negative electrode mixture layer 205 A solid electrolyte for ensuring ionic conductivity may be included.

  The thickness of the negative electrode mixture layer 205 is designed in accordance with the energy density, rate characteristics, and input / output characteristics of the all-solid-state battery, but generally has a size of several μm to several hundred μm. The particle size of the material such as the positive electrode active material included in the negative electrode mixture layer 205 is defined to be equal to or less than the thickness of the negative electrode mixture layer 205. When the positive electrode active material powder has coarse particles having a particle size equal to or larger than the thickness of the negative electrode mixture layer 205, the coarse particles are previously removed by sieving classification, wind classification, etc. Prepare the particles.

<Separator>
The positive electrode separator 106 and the negative electrode separator 206 contain a solid electrolyte. As the solid _{electrolyte, Li 10 Ge 2 PS 12,} Li2S-P 2 S sulfide such as _{5, Li-La-Zr-} O oxide system such as, organic polymer and ionic liquid or ionic liquid and inorganic particles Examples thereof include materials that do not exhibit fluidity within the operating temperature range of a secondary battery, such as a polymer type supported on a semi-solid electrolyte, a semi-solid electrolyte, and the like. The solid electrolyte layer is formed by compressing powder, mixing with a binder, applying the slurryed solid electrolyte layer to a release material, or impregnating a carrier. The thickness of the solid electrolyte layer is a size of several nm to several mm from the viewpoint of ensuring the energy density of the secondary battery, ensuring electronic insulation, and the like.
FIG. 3 is a schematic plan view illustrating a stacking procedure using a jig for a stacked secondary battery according to an embodiment of the present invention. The lamination jig 300 is a jig used for laminating electrodes without deviation in the manufacturing process of the laminated secondary battery 10.

  The lamination jig 300 has a depression 310 for a lamination jig. The stacking jig 300 has a shape that defines only the side in the upper surface direction and the side in the side surface direction of the positive electrode terminal portion 103 and the negative electrode terminal portion 203, and has a structure that does not contact the positive electrode stack portion 102 and the negative electrode stack portion 202. Have. In other words, it is designed such that the length in the upper surface direction of the laminated jig recess 310 is shorter than the length in the upper surface direction of the electrode terminal portion. The lamination jig 300 may be brought into contact with the positive electrode lamination part 102 and the negative electrode lamination part 202. By adopting a structure in which the laminated jig 300 is not in contact with the positive electrode laminated portion 102 and the negative electrode laminated portion 202, even when the laminated jig 300 for alignment at the electrode terminal portion is used, the upper surface of the electrode laminated portion is made of an electrode. The electrodes can be aligned without being aligned.

  In addition, since the electrode having a size different from that of the positive electrode and the negative electrode and having the separator formed on the electrode is set in the laminated jig 300, a short circuit due to the displacement of the electrode can be reduced. In addition, since the electrodes are positioned on the side in the upper surface direction and the side in the side surface direction of the positive electrode terminal portion 103 and the negative electrode terminal portion 203, the size of the positive electrode terminal portion 103 and the negative electrode terminal portion 203 is reduced, so The volume energy density of the secondary battery can be improved.

  In FIG. 3A, the laminated jig 300 is set. In FIG. 3B, the positive electrode 101 is set so that the positive electrode terminal portion 103 is aligned with the lamination jig recess 310 of the lamination jig 300. In FIG. 3C, the negative electrode 201 is set so that the negative electrode terminal portion 203 is aligned with the lamination jig recess 310 of the lamination jig 300. 3B and 3C are repeated to form an electrode group in which a plurality of positive electrodes 101 and a plurality of negative electrodes 201 are stacked.

  In FIG. 3D, the electrode terminal portions of the positive electrodes 101 and the negative electrodes 201 are connected. Specifically, after the positive electrode 101 and the negative electrode 201 are stacked on the lamination jig 300, the positive electrode terminal portion 103, the negative electrode terminal portion 203, and the external connection terminal 400 in a state where the positive electrode 101 and the negative electrode 201 are accommodated in the lamination jig 300. Are joined. In that case, positional displacement can be further prevented by connecting the external connection terminal 400 to the electrode terminal portion in a state of being set on the laminated jig 300. Furthermore, when the external connection terminal 400 is connected to the electrode terminal portion, the positive electrode terminal portion 103 or the negative electrode terminal portion 203 and the external connection terminal 400 are joined at two or more locations, thereby preventing electrode displacement. it can.

The electrode terminal portion can be notched in order to improve alignment accuracy. FIG. 4 is a schematic plan view showing a notch shape of the terminal portion according to the embodiment of the present invention.
In FIG. 4A, two semicircular cutouts 320 are provided on the upper side of the electrode terminal portion. By forming the opposite shape of the notch 320 in the laminated jig 300, the alignment accuracy can be improved with the notch 320 as a mark.

  In FIG. 4B, triangular cutouts 320 are provided on the left and right sides of the electrode terminal portion. Similar to FIG. 4A, not only the alignment accuracy can be improved, but also the alignment accuracy can be further improved by making the shape of the notch 320 an acute angle. Further, the positions of the left and right cutouts are shifted in order to reduce the breakage of the electrode current collector foil when the electrodes are set on the lamination jig 300 in order to laminate the electrodes. The electrode current collector foil is likely to be cut from an acute angle portion, and when the positions of the notches 320 are aligned, the width of the acute angle portion is shortened, so that the electrode current collector foil is easily cut. In order to alleviate the cutting of the electrode current collector foil, the positions of the left and right cutouts are shifted.

  In FIG. 4C, semi-hexagonal notches 320 are provided on the left and right sides. It is a shape that gives the highest priority to reducing the breakage of the electrode current collector foil when the electrode is set on the lamination jig 300 for laminating the electrodes, and can be preferably applied when the electrode terminal portion becomes narrow.

  By using the positioning exterior material 500 of the stacked secondary battery 10 instead of the stacked jig 300, the accuracy of electrode alignment can be improved without using the stacked jig 300. FIG. 5 is a schematic plan view showing an example of a stacked secondary battery according to an embodiment of the present invention. The positive electrode 101 and the negative electrode 201 are accommodated in the positioning exterior material 500 and the facing exterior material 501.

  In FIG. 5, the positioning accuracy of the electrode can be improved by attaching the exterior material recess 510 to the positioning exterior material 500 to define the storage position of the electrode terminal portion. At this time, the exterior material recess 510 formed in the positioning exterior material 500 is substantially the same as the electrode terminal portion, or the exterior material recess 510 has a structure that does not contact the positive electrode laminate portion 102 and the negative electrode laminate portion 202. Alignment at the electrode terminal portion is possible without using the laminated jig 300. In order to increase the alignment accuracy of the electrodes, it is desirable that the corners of the exterior material recess 510 formed in the positioning exterior material 500 are at right angles. In this case, an exterior material recess 510 for accommodating the electrode stack portion may be provided, but the corner of the exterior material recess 510 in the region for storing the electrode stack portion need not be a right angle.

DESCRIPTION OF SYMBOLS 10 ... Stack type secondary battery 20 ... Unit cell 101 ... Positive electrode 102 ... Positive electrode laminated part 103 ... Positive electrode terminal part 104 ... Positive electrode collector foil 105 ... Positive electrode compound material layer 106 ... Positive electrode separator 201 ... Negative electrode 202 ... Negative electrode laminated part 203 ... Negative electrode terminal portion 204 ... Negative electrode current collector foil 205 ... Negative electrode composite material layer 206 ... Negative electrode separator 300 ... Lamination jig 310 ... Lamination 320 for lamination jig ... Notch 400 ... External connection terminal 500 ... Positioning exterior material 501 ... Facing exterior material 510 ... Exterior Recess for material 800 ... Auxiliary line

Claims (6)

A method for producing a laminated secondary battery in which a positive electrode and a negative electrode are laminated,
The positive electrode has a positive electrode terminal part and a positive electrode laminate part,
The negative electrode has a negative electrode terminal portion and a negative electrode laminate portion,
The positive electrode laminate and the negative electrode laminate are different in size,
A separator is formed on the positive electrode or the negative electrode,
When viewed from the stacking direction, the positive terminal portion and the negative terminal portion are formed at different positions,
A step of setting a lamination jig having a depression for the lamination jig;
A step of setting the upper surface direction and the side surface direction of the positive electrode terminal portion or the negative electrode terminal portion of the positive electrode or the negative electrode on which the separator is formed according to the depression for the laminated jig;
Laminating the positive electrode and the negative electrode to produce a laminated secondary battery. In the manufacturing method of the lamination type secondary battery of Claim 1,
The method of manufacturing a laminated secondary battery, wherein the length of the depression for the laminated jig is smaller than the length of the positive electrode terminal or the negative electrode terminal portion of the positive electrode or the negative electrode on which the separator is formed. In the manufacturing method of the lamination type secondary battery of Claim 1,
A method of manufacturing a stacked secondary battery, wherein the size of the positive electrode or the negative electrode on which the separator is formed and the positive electrode stack or the negative electrode stack is the same when viewed from the stacking direction. In the manufacturing method of the lamination type secondary battery of Claim 1,
After the positive electrode and the negative electrode are laminated on the laminated jig, the positive electrode terminal portion, the negative electrode terminal portion and the external connection terminal are joined in a state where the positive electrode and the negative electrode are housed in the laminated jig. A method for manufacturing a stacked secondary battery. In the manufacturing method of the lamination type secondary battery of Claim 1,
A method for manufacturing a laminated secondary battery, wherein the positive electrode terminal portion or the negative electrode terminal portion and the external connection terminal are joined at two or more locations. In the manufacturing method of the lamination type secondary battery of Claim 1,
A method for manufacturing a laminated secondary battery, wherein the laminated jig is a positioning exterior material that houses the positive electrode and the negative electrode.

Images