Source: https://patents.google.com/patent/JPWO2006120959A1/en
Timestamp: 2020-01-29 00:00:51
Document Index: 681203368

Matched Legal Cases: ['art 1', 'art 2', 'art 8', 'art 16', 'art 9', 'art 10', 'art 17', 'art 11', 'art 8', 'art 10', 'art 8', 'art 26', 'art 26', 'art 4', 'art 5', 'art 1', 'art 2']

JPWO2006120959A1 - Battery - Google Patents
JPWO2006120959A1
JPWO2006120959A1 JP2006535882A JP2006535882A JPWO2006120959A1 JP WO2006120959 A1 JPWO2006120959 A1 JP WO2006120959A1 JP 2006535882 A JP2006535882 A JP 2006535882A JP 2006535882 A JP2006535882 A JP 2006535882A JP WO2006120959 A1 JPWO2006120959 A1 JP WO2006120959A1
JP2006535882A
JP3993223B2 (en
岡崎　禎之
美濃　辰治
宇賀治　正弥
平本　雅祥
雅祥 平本
2005-05-10 Priority to JP2005137656 priority Critical
2005-05-10 Priority to JP2005137656 priority
2006-05-01 Application filed by 松下電器産業株式会社 filed Critical 松下電器産業株式会社
2006-05-01 Priority to PCT/JP2006/309096 priority patent/WO2006120959A1/en
2007-10-17 Publication of JP3993223B2 publication Critical patent/JP3993223B2/en
2008-12-18 Publication of JPWO2006120959A1 publication Critical patent/JPWO2006120959A1/en
In the battery of the present invention, the separator is folded in a zigzag manner, and is alternately arranged. The laminated body having at least one first electrode housing portion and at least one second electrode housing portion, and the first electrode housing portion. The first electrode accommodated and the second electrode accommodated in the second electrode accommodating portion are provided. At least one of the first electrode and the second electrode has at least one protrusion. The first electrode is connected to the first terminal, and the second electrode is connected to the second terminal.
The present invention relates to a battery that can sufficiently secure a connection between a current collector and an external terminal.
As electronic devices and electric devices become smaller, lighter, or thinner, electrochemical elements such as secondary batteries that are used as power sources are also required to be smaller, lighter, or thinner. For example, a lithium secondary battery was obtained by laminating a positive electrode in which a positive electrode active material layer was formed on a current collector and a negative electrode in which a negative electrode active material layer was formed on a current collector with a separator interposed therebetween. A roll-type electrode plate group obtained by winding a sheet having a three-layer structure or an electrode plate group having a laminated structure in which the three-layer structure sheet is folded in multiple stages is used. Furthermore, a plurality of positive electrode sheets and a plurality of negative electrode sheets are alternately stacked via separators, and an electrode plate group folded in a zigzag manner so that the separators are sewn between the positive electrode sheets and the negative electrode sheets. It has been proposed (see, for example, Patent Document 1).
On the other hand, in order to increase the volume energy density, for example, it is proposed to stack a positive electrode active material or a negative electrode active material on a separator and form a thin internal electrode layer (current collector) on the active material. (For example, refer to Patent Document 2). Thus, a thin and high energy density battery can be realized by reducing the thickness of the current collector and increasing the volume energy density.
Furthermore, in order to improve the output characteristics, reliability and capacity of the battery, it has been proposed to use a current collector sheet comprising a resin sheet and a conductive layer having a predetermined shape pattern provided on both surfaces thereof. (For example, refer to Patent Document 3).
JP 2002-329530 A JP-A-8-138726 JP 2004-253340 A
However, in a battery having a structure as described in Patent Document 1, when the current collector becomes very thin, the current collectors included in the plurality of positive electrode sheets or the plurality of negative electrode sheets are connected to the external terminals. It becomes difficult.
In Patent Document 2, a unit having a separator, an active material layer formed on the separator, and an internal electrode layer formed on the active material layer is folded in two with the internal electrode layer inside. Yes. In the unit folded in half, the thickness of the separator is doubled. For this reason, although the internal electrode layer is thinned, the thickness of the battery may not be thinned. Therefore, the volume energy density cannot be significantly improved. Further, as described above, since the internal electrode layer is very thin, it is difficult to connect the internal electrode layer included in the unit to the external terminal.
When a current collector having a conductive layer made of a metal thin film on a resin sheet is used as in Patent Document 3, the battery includes a resin sheet that is not related to the battery reaction, so that the energy density is reduced. In the case of using a current collector made of only a metal thin film, the current density does not decrease because the current collector does not include a resin sheet. However, when the current collector made of a metal thin film has a thickness of 5 μm or less, it becomes difficult to handle the current collector unless it is supported by the support.
Accordingly, an object of the present invention is to provide a battery that can sufficiently secure the connection between the current collector and the external terminal even when the current collector is as thin as 5 μm or less.
The battery of the present invention includes at least one first electrode, at least one second electrode, and a strip-shaped separator. The separator constitutes a laminate having at least one first electrode housing portion and at least one second electrode housing portion that are folded in a zigzag manner and are alternately arranged. The laminated body has a first end surface on which at least one first bent portion is disposed and a second end surface on which at least one second bent portion is disposed. The first end face is located on the opposite side of the second end face. The first electrode housing part has an open part on the first end face side, and the second electrode housing part has an open part on the second end face side. A first electrode is accommodated in the first electrode accommodating portion, and the second electrode is accommodated in the second electrode accommodating portion. Each of the first electrode and the second electrode has two electrode parts including a current collector and an active material layer carried on one side thereof, and the two electrode parts are arranged such that the current collectors are in contact with each other. Has been placed. In at least one of the first electrode and the second electrode, at least one of the two electrode portions has a protrusion protruding toward the open portion of the end face. The protrusion includes a current collector and an active material layer. The first end surface includes a first terminal connected to the first electrode, and the second end surface includes a second terminal connected to the second electrode. Each of the first terminal and the second terminal is preferably made of a metal film. In addition, each of the first terminal and the second terminal preferably includes a lead.
In at least one of the first electrode and the second electrode, the two electrode portions include a current plate made of a current collector and an active material layer supported on one surface thereof, and an active material layer of the current collector. You may comprise by bending so that the surfaces which are not carry | supported may contact. Alternatively, the two electrode portions are arranged such that two surfaces of the current collector and the active material layer supported on one surface thereof are in contact with the surfaces of the current collector not supporting the active material layer. You may comprise by laminating | stacking.
When two electrode portions are formed by bending one electrode plate, when the electrode plate is bent, the positions of the two sides parallel to the bending axis of the electrode plate are set in the length direction of the electrode plate. By shifting, it is preferable that the protrusion is provided on only one of the two electrode portions over the entire width direction of the electrode portion.
In at least one of the first electrode and the second electrode, each of the two electrode portions is preferably provided with a protrusion having the same area. The thickness of the current collector contained in at least one of the first electrode and the second electrode is preferably 0.1 μm to 5 μm.
The electrode accommodated in each electrode accommodating portion at both ends of the laminate is composed of one electrode plate including a current collector and an active material layer supported on one surface thereof, and the active material layer is adjacent to the electrode accommodating It is preferable to face the active material layer of the electrode accommodated in the part via the separator.
The present invention also relates to a battery including two first electrodes, a second electrode, and a strip-shaped separator. The separator is folded in a zigzag manner to form a laminated body having two first electrode housing portions and one second electrode housing portion arranged therebetween. The laminate has a first end surface on which one first bent portion is disposed and a second end surface on which two second bent portions are disposed, and the first end surface is located on the opposite side of the second end surface. Yes. The first electrode housing part has an open part on the first end face side, and the second electrode housing part has an open part on the second end face side. The first electrode is accommodated in the first electrode accommodating portion, and the second electrode is accommodated in the second electrode accommodating portion. The first electrode has one electrode portion including a current collector and an active material layer carried on one surface thereof. The second electrode has two electrode portions including a current collector and an active material layer carried on one surface thereof, and the two electrode portions are arranged so that the current collectors are in contact with each other. Each of the first electrodes has an active material layer facing the active material layer of the second electrode via a separator. At least one of the two electrode portions of the second electrode and the electrode portion of the first electrode has at least one protrusion protruding toward the open portion of the end face, and the protrusion includes a current collector and an active material layer Including. The first end surface includes a first terminal connected to the first electrode, and the second end surface includes a second terminal connected to the second electrode.
In the battery of the present invention, at least one of the first electrode and the second electrode has a protrusion protruding toward the open portion. Furthermore, each of the first electrode and / or each of the second electrodes included in the battery is connected to a terminal via a protrusion. Therefore, even when the current collector is thin, it is possible to reliably collect current from the current collector by providing the terminal on the end surface from which the protrusion protrudes.
It is a longitudinal cross-sectional view which shows roughly the electrode group used for the battery concerning one Embodiment of this invention. It is a longitudinal cross-sectional view which shows roughly the electrode group used for the battery concerning another embodiment of this invention. It is a top view which shows roughly the 1st electrode contained in the battery concerning one Embodiment of this invention. It is a bottom view which shows roughly the 1st electrode contained in the battery concerning one Embodiment of this invention. The longitudinal cross-sectional view when the 1st electrode of FIG. 2 is cut off by line AA is shown. The longitudinal cross-sectional view when the 1st electrode of FIG. 2 is cut off by line BB is shown. It is a figure which shows the 1st positive electrode part and 2nd positive electrode part which comprise the 1st electrode of FIG. 2 in the separated state. It is a top view which shows roughly an example of the 2nd electrode contained in the battery concerning one Embodiment of this invention. It is a bottom view which shows roughly an example of the 2nd electrode contained in the battery concerning one Embodiment of this invention. The longitudinal cross-sectional view when the 2nd electrode of FIG. 7 is cut off by line CC is shown. The longitudinal cross-sectional view when the 2nd electrode of FIG. 7 is cut off by line DD is shown. It is a top view which shows roughly the 1st electrode contained in the battery concerning another embodiment of this invention. It is a top view which shows roughly the 2nd electrode contained in the battery concerning another embodiment of this invention. It is a top view which shows roughly the electrode contained in the battery concerning another embodiment of this invention. It is a figure for demonstrating the preparation methods of an electrical power collector and the active material layer carry | supported on it. It is a top view which shows arrangement | positioning of the 1st electrode and 2nd electrode in the electrode group contained in the battery concerning one Embodiment of this invention. The longitudinal cross-sectional view in line EE of FIG. 14 is shown. The longitudinal cross-sectional view in line FF of FIG. 14 is shown. It is a top view which shows arrangement | positioning of the 1st electrode and 2nd electrode in the electrode group contained in the battery concerning another embodiment of this invention. FIG. 18 is a longitudinal sectional view taken along line GG in FIG. 17. FIG. 18 is a longitudinal sectional view taken along line HH in FIG. 17. It is a longitudinal cross-sectional view of the electrode group which laminated | stacked the some 1st electrode and the some 2nd electrode through one separator. It is a longitudinal cross-sectional view which shows schematically the electrode group of FIG. 22 in which the 1st terminal and 2nd terminal which were each provided in a different end surface were provided. It is a figure which shows four surfaces used as a bottom face in a drop test.
The battery of the present invention includes at least one first electrode, at least one second electrode, and a strip-shaped separator. The separator constitutes a laminate having at least one first electrode housing portion and at least one second electrode housing portion that are folded in a zigzag manner and are alternately arranged. The laminated body has a first end surface on which at least one first bent portion is disposed and a second end surface on which at least one second bent portion is disposed. The first end face is located on the opposite side of the second end face. The first electrode housing part has an open part on the first end face side, and the second electrode housing part has an open part on the second end face side. The first electrode is accommodated in the first electrode accommodating portion, and the second electrode is accommodated in the second electrode accommodating portion. Each of the first electrode and the second electrode has two electrode parts including a current collector and an active material layer carried on one side thereof, and the two electrode parts are arranged such that the current collectors are in contact with each other. Has been placed. In at least one of the first electrode and the second electrode, at least one of the two electrode portions has a protrusion protruding toward the open portion of the end face. The protrusion includes a current collector and an active material layer. The first end surface includes a first terminal connected to the first electrode, and the second end surface includes a second terminal connected to the second electrode.
FIG. 1 shows an electrode plate group used in a battery according to an embodiment of the present invention. In this embodiment, the case where the battery of the present invention is a lithium ion secondary battery will be described. Note that the present invention is also applicable to other secondary batteries.
The electrode plate group shown in FIG. 1 includes four first electrodes 3, three second electrodes 6, and one strip-shaped separator 7. In the following description, the first electrode is a positive electrode and the second electrode is a negative electrode. Note that the first electrode may be a negative electrode and the second electrode may be a positive electrode.
Each positive electrode 3 includes two electrode portions, that is, a first positive electrode portion 1 and a second positive electrode portion 2. The first positive electrode portion 1 includes a strip-shaped first positive electrode current collector 1a and a first positive electrode active material layer 1b supported on one surface thereof. The second positive electrode portion 2 includes a strip-shaped second positive electrode current collector 2a and a second positive electrode active material layer 2b supported on one surface thereof.
Similarly, each negative electrode 6 includes a first negative electrode portion 4 and a second negative electrode portion 5. The first negative electrode portion 4 includes a strip-shaped first negative electrode current collector 4a and a first negative electrode active material layer 4b supported on one surface thereof. The second negative electrode portion 5 includes a strip-shaped second negative electrode current collector 5a and a second negative electrode active material layer 5b supported on one surface thereof.
In the positive electrode 3, the first positive electrode part 1 and the second positive electrode part 2 support the surface where the active material layer of the first positive electrode current collector 1 a is not supported and the active material layer of the second positive electrode current collector 2 a. It is laminated so that the surface that does not overlap. Also in the negative electrode 6, the first negative electrode portion 4 and the second negative electrode portion 5 include a surface on which the active material layer of the first negative electrode current collector 4 a is not carried and an active material layer of the second negative electrode current collector 5 a. It is laminated so that the non-supported surface overlaps.
The separator 7 constitutes a laminated body having first electrode housing portions 8 and second electrode housing portions 10 that are folded in a zigzag manner and are alternately arranged. In FIG. 1, the laminate includes four first electrode (positive electrode) accommodating portions 8 and three second electrode (negative electrode) accommodating portions 10. In addition, the laminate has a first end surface on which three first bent portions 11 are arranged and a second end surface on which four second bent portions 9 are arranged. The first end face is located on the opposite side of the second end face.
The 1st electrode accommodating part 8 has the open part 16 in the 1st end surface side, and has the 2nd bending part 9 in the 2nd end surface side. The 2nd electrode accommodating part 10 has the open part 17 in the 2nd end surface side, and has the 1st bending part 11 in the 1st end surface side. The positive electrode 3 is housed in the first electrode housing portion 8, and the negative electrode 6 is housed in the second electrode housing portion 10. The active material layer of the positive electrode 3 and the active material layer of the negative electrode 6 are opposed to each other through the separator 7.
In addition, in FIG. 1, the cross section of the 1st electrode accommodating part 8 and the 2nd electrode accommodating part 10 is U-shaped. The cross section of each electrode housing portion does not have to be a shape that is strictly composed of only a straight line and a curve, and the curved portion may be a U-shape that is a straight line. Alternatively, the curved line portion may be formed of a plurality of straight line portions. Further, the cross section of the electrode housing portion may be V-shaped. In actual batteries, if the separator is slack, its cross section may be U-shaped, and when the separator is tensioned, its cross-section becomes V-shaped or U-shaped. Sometimes.
In the present invention, in at least one of the first electrode and the second electrode, at least one of the two electrode portions has at least one protrusion. FIG. 1 shows a case where each of the two electrode portions has one protrusion in both the positive electrode and the negative electrode.
Each of the two electrode portions of the positive electrode 3 has a protrusion that protrudes toward the open portion 16 located on the first end face of the first electrode housing portion 8. The two electrode portions of the negative electrode 6 each have a protrusion that protrudes toward the open portion 17 located on the second end face of the second electrode housing portion 10. These protrusions are composed of a current collector and an active material layer. In FIG. 1, a protrusion 2 c provided on the second positive electrode piece 2 and a protrusion 4 c provided on the first negative electrode piece 4 are shown.
A first terminal (positive electrode current collecting terminal) 12 is formed on a first end face from which a protrusion provided on the positive electrode protrudes. A second terminal (negative electrode current collecting terminal) 13 is formed on the second end face from which the protrusion provided on the negative electrode protrudes. The protrusion provided on each positive electrode is connected to the first terminal 12, and the protrusion provided on each negative electrode is connected to the second terminal 13.
Thus, the positive electrode and the negative electrode are each provided with protrusions, so that the current collector is reliably supported by the active material layer even when the current collector is as thin as 0.1 to 5 μm. In addition, the connection area between the current collector and the terminal increases. For this reason, it is possible to reliably connect the current collector and the terminal. In the present invention, since the current collector is supported by the active material layer, the thickness of the current collector can be reduced to 0.1 to 5 μm. Note that when the thickness of the current collector is thinner than 0.1 μm, the specific resistance of the current collector may increase.
The thicknesses of the first terminal and the second terminal in the direction perpendicular to the thickness direction of the separator stack are preferably 0.1 mm to 1 mm, respectively.
Further, a first lead 14 is connected to the first terminal 12, and a second lead 15 is connected to the second terminal 13. The first terminal is connected to all positive electrodes, and the second terminal is connected to all negative electrodes. For this reason, even when there are a plurality of positive electrodes and negative electrodes, the lead terminals may be connected to the first terminal and the second terminal, respectively. Therefore, it is not necessary to connect a lead terminal to each of all the electrodes.
As shown in FIG. 1, the first terminal 12 and the second electrode 6 do not contact each other because the first bent portion 11 of the separator 7 is interposed therebetween. The second terminal 13 and the first electrode 3 are not in contact with each other because the second bent portion 9 of the separator 7 is interposed therebetween.
The positive electrode active material layer includes a positive electrode active material. In the case of a lithium ion secondary battery, for example, a lithium-containing transition metal oxide can be used as the positive electrode active material. Examples of the lithium-containing transition metal oxides, for example, Li x CoO z, Li x NiO z, Li x MnO z, Li x Co y Ni 1-y O z, Li x Co f V 1-f O z, Li x Ni 1-y M y O z (M = Ti, V, Mn, Fe), Li x Co a Ni b M c O z (M = Ti, Mn, Al, Mg, Fe, Zr), Li x Mn 2 O 4 , Li x Mn 2 (1-y) M 2y O 4 (M = Na, Mg, Sc, Y, Fe, Co, Ni, Ti, Z, Cu, Zn, Al, Pb, Sb) and the like. It is done. However, the x value varies in the range of 0 ≦ x ≦ 1.2 depending on the charge / discharge of the battery. Also, 0 ≦ y ≦ 1, 0.9 ≦ f ≦ 0.98, 1.9 ≦ z ≦ 2.3, a + b + c = 1, 0 ≦ a ≦ 1, 0 ≦ b ≦ 1, 0 ≦ c <1 is there. These may be used alone or in combination of two or more.
Note that the positive electrode active material to be used is appropriately changed depending on the type of battery to be manufactured.
The negative electrode active material layer includes a negative electrode active material. In the case of a lithium ion secondary battery, examples of the negative electrode active material include lithium, lithium alloys, intermetallic compounds, carbon materials, silicon (Si), silicon oxide (SiO x ), tin (Sn), and lithium ions. A releasable organic compound, inorganic compound, metal complex, and organic polymer compound can be used. These may be used alone or in combination of two or more.
Carbon materials include coke, pyrolytic carbon, natural graphite, artificial graphite, mesocarbon microbeads, graphitized mesophase microspheres, vapor grown carbon, glassy carbon, carbon fibers (polyacrylonitrile, pitch, cellulose, Vapor phase growth system), amorphous carbon, and organic compound fired body. Of these, natural graphite and artificial graphite are particularly preferable.
If the negative electrode active material is Si, comprising at least one SiO x and Sn, the negative electrode active material layer may be a deposited film containing these elements.
Note that the type of the negative electrode active material is appropriately changed depending on the type of the battery to be manufactured.
The positive electrode active material layer and the negative electrode active material layer may contain a conductive material and / or a binder as necessary. In the case of a lithium ion secondary battery, as the conductive material, for example, carbon black such as acetylene black and graphite can be used. As the binder, for example, fluororesin such as polyvinylidene fluoride and polytetrafluoroethylene, acrylic resin, styrene butadiene rubber, and ethylene propylene terpolymer can be used.
The types of the conductive material and the binder are also appropriately changed according to the type of battery.
As the positive electrode current collector and the negative electrode current collector, a sheet or a thin film made of a metal material known in the art can be used. In the case of a lithium ion secondary battery, the material constituting the positive electrode current collector includes aluminum. An example of the material constituting the negative electrode current collector is copper.
As a material constituting the positive electrode current collecting terminal which is the first terminal, a material known in this field can be used. For example, a metal aluminum film or a porous film made of metal aluminum can be used as the positive electrode current collecting terminal. As a material constituting the negative electrode current collecting terminal which is the second terminal, a material known in this field can be used. For example, a copper metal film or a porous film made of copper can be used as the negative electrode current collecting terminal. When the first electrode is a negative electrode and the second electrode is a positive electrode, the first terminal is a negative electrode current collector terminal and the second terminal is a positive electrode current collector terminal.
The first terminal and the second terminal can be formed by vacuum deposition, sputtering, thermal spraying, or the like. Moreover, you may form a 1st terminal and a 2nd terminal by apply | coating the electrically conductive paste containing a metal particle to each end surface, and making it dry.
By using the first terminal and the second terminal as described above, these terminals and the current collector can be reliably connected.
For the separator, for example, an olefin polymer such as polyethylene or polypropylene, or a woven or non-woven fabric made of glass fiber can be used.
As the positive electrode lead 14 and the negative electrode lead 15, those known in the art can be used. As a material constituting the positive electrode lead, for example, metallic aluminum can be used. As a material constituting the negative electrode lead, for example, metallic nickel can be used. When the first electrode is a negative electrode and the second electrode is a positive electrode, the first lead is a negative electrode lead and the second lead is a positive electrode lead.
Further, the first lead and the second lead may be embedded in the first terminal and the second terminal, respectively. Thereby, the lead can be more reliably connected to the terminal.
In FIG. 1, first electrode housing portions 8 a and 8 b are positioned at both ends of the separator stack in the thickness direction. The positive electrodes accommodated in the first electrode accommodating portions 8a and 8b are preferably composed of one electrode plate 18 and 19 each including a current collector and an active material layer carried on one side thereof. At this time, the positive electrode active material layer accommodated in the first electrode accommodating portions 8a and 8b is opposed to the negative electrode active material layer accommodated in the adjacent second electrode accommodating portion via the separator.
As shown in FIG. 1, the current collector surface is not covered with a separator so that at least a part of the positive electrode current collector surface of the positive electrode housed in the first electrode housing portions 8a and 8b is exposed to the outside. It is preferable to do. This makes it possible to reliably collect current from the electrode plates at both ends in the stacking direction of the electrode plate group. The electrodes accommodated in the first electrode accommodating portions 8a and 8b may or may not have protrusions. In addition, FIG. 1 has shown the electrode group which the electrode accommodated in 1st electrode accommodating part 8a and 8b does not have a protrusion.
Next, an electrode plate group in which one second electrode is sandwiched between two first electrodes will be described with reference to FIG. In FIG. 2, the same components as those in FIG.
The electrode plate group shown in FIG. 2 includes two first electrodes 21 and 22, one second electrode 23, and a strip-shaped separator 7. The separator 7 is folded in a zigzag manner to form a laminated body having two first electrode housing portions 26a and 26b and one second electrode housing portion 27 disposed therebetween. The 1st electrode 21 accommodated in the 1st electrode accommodating part 26a consists of one electrode plate containing the electrical power collector 21a and the active material layer 21b carry | supported on it. Similarly, the 1st electrode 22 accommodated in the 1st electrode accommodating part 26b consists of one electrode plate containing the electrical power collector 22a and the active material layer 22b carry | supported on it. That is, in the electrode plate group of FIG. 2, the first electrode has only one electrode portion.
The second electrode 23 has two electrode portions 24 and 25. The electrode portion 24 includes a current collector 24a and an active material layer 24b supported on one surface thereof. The electrode portion 25 includes a current collector 25a and an active material layer 25b supported on one surface thereof. The electrode portion 24 and the electrode portion 25 are disposed so that the current collector 24a and the current collector 25a are in contact with each other.
In the electrode plate group of FIG. 2, the active material layer 21 b of the first electrode 21 faces the active material layer 24 b of the second electrode 23 through the separator 7, and the active material layer 22 b of the first electrode 22 is The second electrode 23 faces the active material layer 25b with the separator 7 interposed therebetween.
Each of the two electrode portions of the second electrode has a protrusion that protrudes toward the open portion of the second end surface. In FIG. 2, the protrusion 24c of the electrode portion 24 of the second electrode 23 is shown. In FIG. 2, the electrode portion of the first electrode does not have a protrusion. Similarly to the second electrode, the electrode portion of the first electrode may have a protrusion that protrudes toward the open portion of the first end face. Note that the number of protrusions provided on each electrode portion may be one, or two or more.
Next, each of the positive electrode 3 and the negative electrode 6 will be described with reference to the drawings. In the following drawings, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.
FIG. 3 shows a top view of the positive electrode 3, and FIG. 4 shows a bottom view of the positive electrode 3. FIG. 5 shows a vertical cross-sectional view when the positive electrode of FIG. 3 is cut along line AA, and FIG. 6 shows a vertical cross-sectional view when the positive electrode of FIG. 3 is cut along line BB. FIG. 7 shows each of the first positive electrode portion 1 and the second positive electrode portion 2 constituting the positive electrode of FIG.
As shown in FIGS. 3 to 6, in the positive electrode, the first positive electrode portion 1 and the second positive electrode portion 2 have a surface on which the active material layer of the current collector 1 a is not supported and an active material layer of the current collector 2 a. It is laminated so that the non-supported surface is in contact. The first positive electrode portion 1 has a protrusion 1c, and the second positive electrode portion 2 has a protrusion 2c. As shown in FIG. 5, even when the first positive electrode portion 1 and the second positive electrode portion 2 are stacked so that the current collector surfaces are in contact with each other, by providing the protrusion 1 c, the positive electrode of the first positive electrode portion 1 The current collector surface is exposed. Further, as shown in FIG. 6, by providing the protrusion 2c, the positive electrode current collector surface of the second positive electrode portion 2 is exposed. It is preferable that the protrusion 1c and the protrusion 2c do not overlap each other.
The shape of the protrusion is not particularly limited as long as the connection between the protrusion and the terminal is reliably performed. For example, the shape of the protrusion may be, for example, a rectangle, a triangle, or a trapezoid.
The relationship between the length Wt of the side parallel to the width direction of the protrusion 1c, the length Wu of the side parallel to the width direction of the protrusion 2c, and the length Ws of the side parallel to the width direction of the positive electrode is Ws. It is preferable that ≧ Wt + Wu, and it is particularly preferable that Ws> Wt = Wu. Thereby, the connection between each positive electrode and the first terminal can be made more reliable.
Moreover, it is preferable that the exposed area Su of the current collector in the protrusion 1c and the exposed area St of the current collector in the protrusion 2c have the same area. As a result, the first positive electrode portion 1 and the second positive electrode portion 2 can have the same connection resistance.
The protrusion length of the protrusion may be 0.5 mm to 1 cm. Thereby, the effect of this invention can fully be acquired.
The negative electrode 6 will be described with reference to FIGS.
FIG. 8 shows a top view of the negative electrode 6, and FIG. 9 shows a bottom view of the negative electrode 6. FIG. 10 shows a longitudinal sectional view when the negative electrode of FIG. 8 is cut along line CC, and FIG. 11 shows a longitudinal sectional view when the negative electrode of FIG. 8 is cut along line DD.
8-11, in the negative electrode 6, the 1st negative electrode part 4 and the 2nd negative electrode part 5 are the surface which does not carry the active material layer of the collector 4a, and the active material of the collector 5a. The layers are stacked so that the surfaces not carrying the layers are in contact with each other. The first negative electrode portion 4 has a protrusion 4c, and the second electrode portion 5 has a protrusion 5c. As shown in FIG. 10, even when the first negative electrode portion 4 and the second negative electrode portion 5 are stacked so that the current collector surfaces are in contact with each other, the protrusion 4 c is provided to provide the negative electrode of the first negative electrode portion 4. The current collector surface is exposed. Further, as shown in FIG. 11, by providing the protrusion 5 c, the negative electrode current collector surface of the second negative electrode portion 5 is exposed. Similarly to the above, it is preferable that the protrusion 4c and the protrusion 5c do not overlap each other.
The relationship between the length Wy of the side parallel to the width direction of the protrusion 4c, the length Wx of the side parallel to the width direction of the protrusion 5c, and the length Wf of the side parallel to the width direction of the negative electrode is Wf ≧ Wx + Wy is preferable, and Wf> Wx = Wy is particularly preferable. The exposed area Sy of the current collector in the protrusion 4c and the exposed area Sx of the current collector in the protrusion 5c are preferably the same area. These reasons are the same as in the case of the positive electrode.
As shown in FIGS. 12 and 13, each of the two electrode portions may have two protrusions.
For example, in the positive electrode, as shown in FIG. 12, two protrusions 1 c provided on the first positive electrode part 1 and two protrusions 2 c provided on the second positive electrode part 2 are arranged in the width direction of the positive electrode. It is preferable to arrange them alternately. Moreover, it is preferable that each protrusion does not mutually overlap.
Also in the negative electrode, as shown in FIG. 13, it is preferable to arrange the two protrusions 4c and the two protrusions 5c alternately in the width direction of the negative electrode, and the protrusions may not overlap each other. preferable.
In FIGS. 12 and 13, two protrusions are provided in each electrode portion, but the number of protrusions provided in each electrode portion may be three or more.
The two electrode parts included in the positive electrode are composed of a single electrode plate including a positive electrode current collector and a positive electrode active material layer supported on one side of the positive electrode current collector. You may comprise by bending so that it may contact. Alternatively, as shown in FIG. 1, the two electrode portions carry two electrode plates including a positive electrode current collector and a positive electrode active material layer carried on one side thereof, and carry the active material layer of the current collector. You may be comprised by overlapping so that the surfaces which are not touching.
When the positive electrode is configured by bending one electrode plate, the protrusion is provided on each of two sides parallel to the bending axis of the electrode plate. At this time, these protrusions are arranged so as not to overlap each other when the electrode plate is bent. The number of protrusions provided on each side may be one or two or more.
Or you may provide a protrusion over the whole width direction of an electrode plate only in one electrode part of a positive electrode. FIG. 14 shows a case where the positive electrode has only the protrusion 2c and the protrusion 2c is provided over the entire width direction of the electrode plate.
When the positive electrode is composed of one electrode plate, when the one electrode plate is bent, the position of two sides parallel to the bending axis of the electrode plate is determined in the length direction of the electrode plate. It can be produced by shifting to
When the positive electrode is composed of two electrode plates, protrusions are provided at the same end portions of the electrode plates, and the protrusions are not overlapped with each other.
The same applies to the negative electrode.
In a lithium ion secondary battery, if the size of the positive electrode is larger than the size of the negative electrode, lithium dendrite may be generated on the negative electrode side during charge and discharge. For this reason, the positive electrode is preferably smaller than the negative electrode. That is, the total Ls of the side parallel to the length direction of the positive electrode and the length of the protrusion shown in FIG. 4 is the length Lf of the side parallel to the length direction of the negative electrode shown in FIG. It is preferable to make it shorter. Further, the length Ws of the side parallel to the width direction of the positive electrode is preferably shorter than the length Wf of the side parallel to the width direction of the negative electrode.
In the positive electrode and the negative electrode, the thickness of the active material layer supported on the current collector is appropriately changed according to the capacity design of the battery. For example, the thickness of the active material layer can be 1 μm to 150 μm.
Next, an example of a method for producing the electrode plate group shown in FIG. 1 will be described.
First, an example of a method for manufacturing a positive electrode and a negative electrode will be described with reference to FIGS.
(A) Production of positive electrode A resin sheet 31 having a predetermined size and having a release agent (release agent) 32 as shown in FIG. As the mold release agent, a melanin-based one containing no Si is desirable. This is because if Si is contained, it may be difficult to peel the metal film from the resin sheet.
Next, a mask having a predetermined shape and an opening of a predetermined size is placed on the release agent 32 of the resin sheet 31. A predetermined metal is deposited on the portion exposed from the opening of the resin sheet 31 to form the positive electrode current collector 33 made of a metal thin film (FIG. 15B). At this time, the metal can be deposited using an evaporation method or the like.
Next, the positive electrode mixture paste is applied to the entire surface of the positive electrode current collector 33 and dried. Thereafter, the dried coating film is rolled to form the positive electrode active material layer 34 on the current collector (FIG. 15C). Rolling of a coating film can be performed using a roller, for example. In addition, since the coating film after drying is rolled, the density of an active material layer is raised.
The positive electrode mixture paste can be prepared by mixing a positive electrode active material, a conductive material, a binder, and the like with a dispersion medium at a predetermined ratio.
When the battery to be manufactured is a lithium ion secondary battery, the above positive electrode active material, conductive material, and binder can be used. The dispersion medium is appropriately selected according to the type of active material, conductive material, and binder used.
The method for applying the positive electrode mixture paste to the current collector is not particularly limited, and methods known in the art can be used. For example, screen printing and pattern coating can be used.
Next, the obtained laminated sheet is cut into a predetermined size and shape to obtain an electrode plate precursor. At this time, the electrode plate precursor is provided with at least one protrusion.
Next, the resin sheet 31 including the release agent 32 is peeled from the current collector 33 (FIG. 15D). Thereby, the electrode plate including the positive electrode current collector and the positive electrode active material layer carried thereon and having the protrusions formed can be obtained. In addition, the protrusion is not shown in FIG.
Thus, a positive electrode can be obtained by producing two electrode plates and laminating them so that the current collector surfaces are in contact with each other. At this time, the two electrode plates are laminated so that the protrusion is located at the same end of the positive electrode.
Alternatively, a positive electrode can be obtained by preparing one electrode plate having at least one protrusion at each end and bending the electrode plate so that the current collectors overlap each other. Also in this case, the protrusion is located only at one end of the positive electrode.
(B) Production of negative electrode The negative electrode can be produced basically in the same manner as the positive electrode.
A resin sheet with a release agent having a predetermined size is prepared. A mask having a predetermined shape and an opening of a predetermined size is placed on the release agent of the resin sheet. A predetermined metal is deposited on a portion exposed from the opening of the resin sheet to form a negative electrode current collector.
Next, the negative electrode mixture paste is applied to the entire surface of the negative electrode current collector and dried. Thereafter, the dried coating film is rolled to form a negative electrode active material layer on the current collector.
The negative electrode mixture paste can be prepared by mixing a negative electrode active material, a binder, and, if necessary, a conductive material with a dispersion medium at a predetermined ratio.
When the battery to be manufactured is a lithium ion secondary battery, the above negative electrode active material, conductive material, and binder can be used. The dispersion medium is appropriately selected according to the type of active material, conductive material, and binder used.
When the negative electrode active material contains at least one of Si, SiOx, and Sn, the negative electrode active material layer may be a deposited film containing at least one element. The deposited film can be produced by, for example, a sputtering method and a vapor deposition method.
Next, the resin sheet provided with the release agent is peeled from the current collector. Thereby, the electrode plate including the negative electrode current collector and the negative electrode active material layer carried thereon and having the protrusions formed can be obtained.
As in the case of the positive electrode, the negative electrode can be obtained by laminating two electrode plates so that the current collector surfaces are in contact with each other. Alternatively, a negative electrode can be obtained by preparing one electrode plate having at least one protrusion at each end and bending the electrode plate so that the current collectors overlap each other.
Note that the positive electrode and the negative electrode can also be produced using a current collector made of a metal foil that has been generally used.
(C) Assembly of electrode plate group One strip-shaped separator is folded in a zigzag manner to obtain a laminated body in which the first electrode housing portions and the second electrode housing portions are alternately arranged. The obtained laminated body has four first electrode housing portions and three second electrode housing portions.
The obtained positive electrode and negative electrode are disposed in the first electrode housing portion and the second electrode housing portion as shown in FIGS. 16 to 18 or as shown in FIGS. At this time, the positive electrode active material layer of the positive electrode and the negative electrode active material layer of the negative electrode are opposed to each other via the separator.
16-18 and 19-21, in the positive electrode 3, the positions of the protrusion 1c provided on the first positive electrode portion and the protrusion 2c provided on the second positive electrode portion are opposite to each other. ing.
FIG. 16 is a top view when one positive electrode and one negative electrode are stacked via a separator. 17 is a longitudinal sectional view taken along line EE in FIG. 16, and FIG. 18 is a longitudinal sectional view taken along line FF in FIG.
FIG. 19 is a top view when one negative electrode and one positive electrode having a protruding portion different from the positive electrode in FIG. 16 are stacked via a separator. 20 is a longitudinal sectional view taken along line GG in FIG. 19, and FIG. 21 is a longitudinal sectional view taken along line HH in FIG.
In FIGS. 16 and 19, the separator is not shown.
As described above, the four positive electrodes 3 and the three negative electrodes 6 can be alternately stacked via separators to obtain a structure as shown in FIG.
One electrode plate including a positive electrode current collector and a positive electrode active material layer carried on one surface thereof is disposed in each of the first electrode housing portions at both ends in the thickness direction of the separator laminate. The positive electrode active material layers disposed in the electrode housing portions at both ends are opposed to the negative electrode active material layers accommodated in the adjacent second electrode housing portions via the separators.
Next, the whole structure is pressed in the stacking direction of the positive electrode and the negative electrode to obtain an aggregate composed of a plurality of positive electrodes, negative electrodes, and separators. In addition, what is necessary is just to implement this press as needed.
The positions of the positive electrode and the negative electrode may be interchanged. In that case, the negative electrode which consists of one negative electrode part is each arrange | positioned in the accommodating part of the both ends of the lamination direction of the said assembly.
Next, as shown in FIG. 23, a first terminal (positive electrode current collecting terminal) 12 is formed in a region (first end surface) where the protrusion of the positive electrode 3 is exposed, and the respective positive electrodes are connected in parallel. The first terminal 12 can be manufactured, for example, by spraying a predetermined metal in a molten state or a semi-molten state on the first end surface.
Similarly, the 2nd terminal (negative electrode current collection terminal) 13 is formed in the 2nd end surface which the protrusion part of the negative electrode 6 exposes, and each negative electrode is connected in parallel. The second terminal 13 can be produced, for example, by spraying a metal different from the metal constituting the first terminal in a molten state or a semi-molten state on the second end surface.
The molten or semi-molten metal can be sprayed, for example, by blowing the molten or semi-molten metal from a nozzle using compressed air.
Next, the positive electrode lead 14 is attached to the first terminal 12, and the negative electrode lead 15 is attached to the second terminal 13, whereby an electrode group as shown in FIG. 1 can be configured.
In addition, the other area | region which does not have the 1st terminal and 2nd terminal of an electrode group may be as it is, and may be coat | covered with the insulating material.
The positive electrode lead 14 can be provided on the first terminal 12 by spraying metal aluminum or the like. Alternatively, a metal lead made of metal aluminum or the like may be welded to the first terminal, and this may be used as a positive electrode lead. Similarly, the negative electrode lead 15 can be provided on the second terminal 13 by spraying metallic nickel or the like. Alternatively, a metal lead made of metallic nickel or the like may be welded to the second terminal, and this may be used as the negative electrode lead.
The positive electrode lead 14 and the negative electrode lead 15 may be embedded in the first terminal 12 and the second terminal 13, respectively. For example, the embedding of the positive electrode lead can be performed by forming the first terminal, placing the positive electrode lead on the first terminal, and again spraying the metal constituting the first terminal from the first terminal, for example. it can. The same applies to the embedding of the negative electrode lead.
The electrode group as shown in FIG. 1 is usually housed in a predetermined case together with the electrolytic solution, and the opening of the case is sealed to produce a battery.
The shape and material of the case are not particularly limited. For example, as the case, a case where a stainless steel plate, an aluminum plate or the like is processed into a predetermined shape, a case made of an aluminum foil (aluminum laminate sheet) having a resin coating on both sides, a resin case, or the like is used.
The electrolyte solution document used is changed as appropriate according to the type of battery. For example, an electrolytic solution used for a lithium ion secondary battery includes a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent. In this case, the concentration of the lithium salt dissolved in the electrolytic solution is preferably 0.5 to 1.5 mol / L.
Nonaqueous solvents include, for example, cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl propyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, etc. Acyclic carbonate, aliphatic carboxylic acid ester such as methyl formate, methyl acetate, methyl propionate, ethyl propionate, γ-lactone such as γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, 1,2 -Acyclic ether such as diethoxyethane and ethoxymethoxyethane, cyclic ether such as tetrahydrofuran and 2-methyl-tetrahydrofuran, dimethyls Sulfoxide, 1,3-dioxolane, trimethyl phosphate, triethyl phosphate, may be used alkyl phosphates such as trioctyl phosphate, and their fluorides. These may be used alone or in combination of two or more. Among these, a mixture containing a cyclic carbonate and an acyclic carbonate, a mixture containing a cyclic carbonate, an acyclic carbonate, and an aliphatic carboxylic acid ester are preferable.
Examples of the lithium salt include LiPF 6 , LiBF 4 , LiClO 4 , LiAlCl 4 , LiSbF 6 , LiSCN, LiCl, LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiN (CF 3 SO 2 ) 2 , Li 2. B 10 Cl 10, LiN (C 2 F 5 SO 2) 2, LiPF 3 (CF 3) 3, and LiPF 3 (C 2 F 5) 3 can be used. These may be used alone or in combination of two or more. Lithium salt preferably includes at least LiPF 6.
With the manufacturing method as described above, for example, an electrode plate group of an arbitrary size can be efficiently manufactured as long as it is in the range of 10 to 300 mm in length, 10 to 300 mm in width, and 0.1 to 5 mm in thickness. it can.
Hereinafter, the present invention will be described based on examples. In this example, a lithium ion secondary battery was produced. In the fabricated battery, the first electrode was a positive electrode and the second electrode was a negative electrode. In addition, the following examples do not limit the present invention.
(Battery A)
(A) Production of positive electrode A polyethylene terephthalate (PET) film with a release agent having a predetermined length was prepared. The PET film had a width of 100 mm and a thickness of 7 μm.
An Al vapor deposition film as a positive electrode current collector was formed on the surface of the PET film provided with a release agent using a predetermined vapor deposition apparatus and a mask having an opening having a size of 80 mm × 50 mm. The formed Al deposited film had a width of 80 mm, a length of 1 m, and a thickness of 1 μm.
Lithium cobaltate (LiCoO 2) 100 parts by weight of the positive electrode active material, and 3 parts by weight of acetylene black as a conductive material, and polyvinylidene fluoride 7 parts by weight as a binder, a suitable amount of aqueous carboxymethyl cellulose solution as a dispersion medium Were mixed to prepare a positive electrode mixture paste. This paste was applied to the entire surface of the Al vapor deposition film to form a coating layer having a width of 80 mm and a length of 1 m. Thereafter, the coating layer was dried and rolled with a roller until the thickness reached 70 μm to obtain a positive electrode active material layer.
Subsequently, a laminated sheet composed of a PET film with a release agent, a positive electrode current collector, and a positive electrode active material layer was punched out to obtain an electrode plate precursor. The electrode plate precursor had a shape in which two protrusions were provided on a rectangle having a length of 150 mm and a width of 45 mm. The shape of the protrusion was rectangular. Here, the first protrusion was provided on one of the sides parallel to the width direction of the rectangle, and the second protrusion was provided on the other side. The protrusion length of the protrusion was 3 mm, and the width of the protrusion was 10 mm. Note that the side parallel to the protruding direction of the protrusion was parallel to the length direction of the rectangle. The side parallel to the width direction of the protrusion was parallel to the width direction of the rectangle.
The center position of the side parallel to the width direction of the first protrusion and the center position of the side parallel to the width direction of the second protrusion are mutually from the center position of the side parallel to the width direction of the rectangle. It was shifted by 5 mm in the reverse direction.
From the electrode plate precursor, the PET film with a release agent was peeled off to obtain a positive electrode plate comprising a positive electrode current collector having two protrusions and a positive electrode active material layer carried thereon.
Bend the obtained electrode plate in the direction in which the current collector surfaces are in contact with each other with the bending axis parallel to the side parallel to the width direction passing through the center of the side parallel to the length direction of the electrode plate. A positive electrode having a size of 3 mm) × 45 mm was obtained. At this time, since the positions of the first and second protrusions are shifted in opposite directions, they did not overlap each other.
In this way, four positive electrodes were prepared.
Further, two positive electrode current collectors and two electrode plates each including the positive electrode current collector were prepared. These electrode plates can be obtained by cutting the positive electrode plate obtained as described above.
(B) Production of negative electrode A PET film with a release agent having a predetermined length was prepared. The width of the PET film was 100 mm and the thickness was 7 μm.
Next, a Cu vapor deposition film as a negative electrode current collector was formed on the surface of the PET film provided with a release agent using a predetermined vapor deposition apparatus and a mask having an opening having a size of 80 mm × 50 mm. The width of the Cu deposited film was 80 mm, the length was 1 m, and the thickness was 1 μm.
By mixing 100 parts by weight of spherical graphite (graphitized mesophase spherules) as a negative electrode active material, 10 parts by weight of styrene butadiene rubber as a binder, and an appropriate amount of carboxymethyl cellulose aqueous solution as a dispersion medium, a negative electrode mixture A paste was prepared.
This paste was applied to the entire surface of the Cu vapor-deposited film to form a coating layer having a width of 80 mm and a length of 1 m. Thereafter, the coating layer was dried and rolled with a roller until the thickness became 73 μm to obtain a negative electrode active material layer.
Subsequently, a laminated sheet composed of a PET film with a release agent, a negative electrode current collector, and a negative electrode active material layer was punched out to obtain the electrode plate body. The electrode plate precursor had a shape in which two protrusions were provided on a rectangle 160 mm long × 47 mm wide. As in the case of the positive electrode, the shape of the protrusion was rectangular. The first protrusion was provided on one of the sides parallel to the width direction of the rectangle, and the second protrusion was provided on the other side parallel to the width direction of the rectangle. The protrusion length of the protrusion was 3 mm, and the width of the protrusion was 10 mm. Note that the side parallel to the protruding direction of the protrusion was parallel to the length direction of the rectangle. The side parallel to the width direction of the protrusion was parallel to the width direction of the rectangle.
From the electrode plate precursor, the PET film with a release agent was peeled off to obtain a negative electrode plate composed of a negative electrode current collector having two protrusions and a negative electrode active material layer carried thereon.
It was obtained so that the current collector surfaces were in contact with each other at a bending axis passing through the center of the side parallel to the length direction of the electrode plate (side of 160 mm) and parallel to the side parallel to the width direction (side of 47 mm). The electrode plate was bent to obtain a negative electrode having a size of (80 mm + projection 3 mm) × 47 mm. At this time, as described above, the protrusions did not overlap each other because their positions were shifted in the opposite directions.
In this way, four negative electrodes were prepared.
(C) Production of electrode plate group A separator having a width of 50 mm, a length of 814 mm, and a thickness of 0.016 mm was prepared. As the separator, a separator having a three-layer structure of a polypropylene layer, a polyethylene layer, and a polypropylene layer was used.
The separator was bent at a position of 75 mm in length from one end. Next, it was bent in the opposite direction at a position advanced by 83 mm, and then bent in a direction opposite to the previous bent direction at a position advanced by 83 mm. Thus, the separator was bent 9 times to obtain a laminate. When this laminate was viewed from the direction of folding, the size was 50 mm wide × 83 mm long. Here, the length of the separator located outside the uppermost part and the lowermost part was shortened to 75 mm so that the current collector surface of the protruding part of the electrode was exposed.
The laminate obtained by folding the separator had a first end surface on which four first bent portions were arranged and a second end surface on which five second bent portions were arranged. In the laminate, the first side surface was located on the opposite side of the second end surface.
Of the five first electrode housing portions, the housing portion other than the housing portion located at the uppermost portion and the housing portion located at the lowermost portion is respectively provided with a positive electrode composed of two electrode portions, and the projecting portion of the first end surface. It arranged so that it might protrude in the open part side. One electrode plate composed of a positive electrode current collector and a positive electrode active material layer carried on one side thereof was disposed in the uppermost and lowermost housing parts. At this time, the positive electrode active material layer was opposed to the negative electrode active material layer through a separator.
In each of the four second electrode housing portions, the negative electrode was disposed so that the protrusion protruded toward the second end face.
Subsequently, the whole structure obtained was pressed to obtain an aggregate.
In the longitudinal section of the obtained assembly, in order from the top, the separator, the positive electrode current collector, the positive electrode active material layer, the separator, the negative electrode active material layer, the negative electrode current collector, the negative electrode active material layer, the separator, the positive electrode active material layer, Positive electrode current collector, positive electrode active material layer, separator, negative electrode active material layer, negative electrode current collector, negative electrode active material layer, separator, positive electrode active material layer, positive electrode current collector, positive electrode active material layer, separator, negative electrode active material layer , Negative electrode current collector, negative electrode active material layer, separator, positive electrode active material layer, positive electrode current collector, positive electrode active material layer, separator, negative electrode active material layer, negative electrode current collector, negative electrode active material layer, separator, positive electrode active material A layer, a positive electrode current collector, and a separator were disposed.
In the assembly, the positive electrode, the separator, and the negative electrode were arranged so that the negative electrode was inside the separator and the positive electrode was inside the negative electrode when viewed from the stacking direction.
Next, Al fine particles in a semi-molten state were sprayed onto the first end face where the protrusions of the positive electrode were exposed to form first terminals made of an Al metal porous film. Thus, the protrusion of each positive electrode was connected to the first terminal. The thickness of the first terminal was 0.5 mm.
Similarly, a second terminal made of a porous film of Cu metal was formed by spraying semi-molten Cu fine particles onto the second end face where the negative electrode protrusion was exposed. Thus, the protrusion of each negative electrode was connected to the second terminal. The thickness of the second terminal was 0.5 mm.
Next, a positive electrode lead made of metallic aluminum was welded to the first terminal, and a negative electrode lead made of metallic nickel was welded to the second terminal. The lead was welded to the terminal by ultrasonic welding. The bonding area between the first terminal and the positive electrode lead and the bonding area between the second terminal and the negative electrode lead were each 0.5 cm 2 . In this way, an electrode plate group was obtained.
Next, the obtained electrode plate group was immersed in a predetermined electrolyte solution, and the electrode plate group was sufficiently impregnated with the electrolyte solution. The electrolytic solution contained a mixed solvent containing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) at a volume ratio of 30:70, and LiPF 6 dissolved in the mixed solvent at a concentration of 1 mol / L.
Next, the electrode group impregnated with the electrolytic solution was put into a bag made of an aluminum laminate sheet, and the opening of the bag was fused and sealed with the positive electrode lead and the negative electrode lead exposed to the outside. In this way, a lithium ion secondary battery was produced. The obtained battery was designated as battery A.
(Battery B)
The positive electrode plate used in the battery A was cut along the center of the side parallel to the length direction (excluding protrusions), that is, along the bending axis to obtain two electrode plates. The two electrode plates were overlapped so that the current collector surfaces overlapped to form a positive electrode having two electrode portions. Similarly, the negative electrode plate used in Battery A was cut along the bending axis to obtain two electrode plates. The two electrode plates were overlapped so that the current collector surfaces overlapped to produce a negative electrode having two electrode portions. Except for these, a lithium ion secondary battery was produced in the same manner as the battery A was produced. The obtained battery was designated as battery B. The battery B and the battery shown in FIG. 1 are the same except that the number of the first electrode housing portions and the second electrode housing portions are different.
(Battery C)
A battery C was produced in the same manner as the battery A, except that the positive electrode as shown in FIG. 12 and the negative electrode as shown in FIG. 13 were used.
A positive electrode was produced as follows.
In the positive electrode plate used in Battery B, two protrusions (length 3 mm × width 5 mm) were provided on each side parallel to the width direction. Specifically, a first protrusion and a second protrusion were provided on the first side parallel to the width direction of the positive electrode plate. The center position of the side parallel to the width direction of the first protrusion was arranged at a position shifted by 2.5 mm from the center position of the first side. The center position of the side parallel to the width direction of the second protrusion is opposite to the position where the first protrusion is provided from the center position of the first side and from the center position of the first side. It was arranged at a position displaced by 7.5 mm.
Similarly, a third protrusion and a fourth protrusion were provided on the second side parallel to the width direction of the positive electrode plate. The center position of the side parallel to the width direction of the third protrusion was arranged at a position shifted by 2.5 mm from the center position of the second side. The center position of the side parallel to the width direction of the fourth protrusion is opposite to the position where the third protrusion is provided from the center position of the second side and from the center position of the second side. It was arranged at a position displaced by 7.5 mm.
The direction in which the first protrusion is provided from the center position of the first side and the direction in which the third protrusion is provided from the center position of the second side are opposite directions.
Using such a positive electrode plate, a positive electrode as shown in FIG. 12 was produced.
The negative electrode was produced as follows.
In the negative electrode plate used in Battery B, two protrusions (length 3 mm × width 5 mm) were provided on each side parallel to the width direction. Specifically, a first protrusion and a second protrusion were provided on the first side parallel to the width direction of the negative electrode plate. The center position of the side parallel to the width direction of the first protrusion was arranged at a position shifted by 2.5 mm from the center position of the first side. The center position of the side parallel to the width direction of the second protrusion is opposite to the position where the first protrusion is provided from the center position of the first side and from the center position of the first side. It was arranged at a position displaced by 7.5 mm.
Similarly, a third protrusion and a fourth protrusion were provided on the second side parallel to the width direction of the negative electrode plate. The center position of the side parallel to the width direction of the third protrusion was arranged at a position shifted by 2.5 mm from the center position of the second side. The center position of the side parallel to the width direction of the fourth protrusion is opposite to the position where the third protrusion is provided from the center position of the second side and from the center position of the second side. It was arranged at a position displaced by 7.5 mm.
Using such a negative electrode plate, a negative electrode as shown in FIG. 13 was produced.
(Battery D)
A positive electrode lead made of aluminum was bonded to the first terminal by blowing semi-molten Al fine particles, and a negative electrode lead made of nickel was bonded to the second terminal by blowing semi-molten Cu fine particles. A battery D was made in the same manner as the battery A, except for the above.
(Battery E)
Battery E was produced in the same manner as Battery A, except that the thickness of the positive electrode current collector was 0.1 μm and the thickness of the negative electrode current collector was 0.1 μm.
(Battery F)
A battery F was produced in the same manner as the battery A, except that the thickness of the positive electrode current collector was 5 μm and the thickness of the negative electrode current collector was 5 μm.
(Battery G)
As the positive electrode current collector, an Al foil sheet having a thickness of 10 μm was used instead of the Al vapor deposition film, and as the negative electrode current collector, a Cu foil sheet having a thickness of 10 μm was used instead of the Cu vapor deposition film. A battery G was produced in the same manner as the battery A, except for the above.
Battery H was produced in the same manner as Battery A, except that the thickness of the positive electrode current collector was 0.05 μm and the thickness of the negative electrode current collector was 0.05 μm.
(Comparison battery I)
Comparative battery I was produced in the same manner as battery A, except that a positive electrode and a negative electrode having no protrusions were used.
The batteries A to H and the comparative battery I obtained as described above were charged with a current value of 0.2C until the battery voltage reached 4.2V. Next, the charged battery was discharged at a current value of 0.2 C until the battery voltage dropped to 3.0V. The battery capacity at this time was determined and used as the initial battery capacity.
Next, a drop test was performed in which each battery after measuring the initial discharge capacity was dropped from a height of 75 cm onto a predetermined plate. At this time, as shown in FIG. 24, each battery was dropped so that the four surfaces indicated by the arrows were the bottom surfaces. The dropping was performed 5 times for each surface. After this drop test, charging and discharging were performed under the same conditions as when the initial discharge capacity was determined, and the battery capacity was determined. Table 1 shows the initial battery capacity and the battery capacity after the drop test. Table 1 also shows the thickness (mm) and volume energy density (Wh / L) of each battery.
As shown in Table 1, in the batteries A to H, no change in the battery capacity was observed even after the drop test. On the other hand, in the comparative battery I, the battery capacity was greatly reduced after the drop test.
The comparative battery I after evaluation was disassembled and cut, and the cross section was observed with a scanning electron microscope (SEM). As a result, several places where the joint part between the terminal and the current collector was cut were recognized.
Moreover, it turned out that the volume energy density becomes small as the thickness of a collector becomes thick from the result of the charge / discharge capacity at 0.2 C of the batteries E to G.
Battery H had a slightly lower initial battery capacity than the other batteries. The thickness of the positive electrode current collector made of an Al vapor deposition film and the thickness of the negative electrode current collector made of a Cu vapor deposition film are each 0.05 μm, and the thickness of the current collector is thin enough to transmit light. It has become. In addition, the current collector has pinholes and is considered to be somewhat porous. For this reason, it is considered that the resistance of the current collector increases, and as a result, the polarization of the electrode increases and the capacity decreases.
According to the present invention, even when the current collector is thin, it is possible to provide a battery with improved current collecting performance. By using such a battery, it is possible to provide a highly reliable device such as a mobile phone, a portable information terminal device, a camcorder, a personal computer, a PDA, a portable audio device, an electric vehicle, and a load leveling power source. Become.
As electronic devices and electric devices become smaller, lighter, or thinner, electrochemical elements such as secondary batteries that are used as power sources are also required to be smaller, lighter, or thinner. For example, a lithium secondary battery was obtained by laminating a positive electrode in which a positive electrode active material layer was formed on a current collector and a negative electrode in which a negative electrode active material layer was formed on a current collector with a separator interposed therebetween. A roll-type electrode plate group obtained by winding a sheet having a three-layer structure, or an electrode plate group having a laminated structure in which the three-layer structure sheet is folded in multiple stages is used. Furthermore, a plurality of positive electrode sheets and a plurality of negative electrode sheets are alternately stacked via separators, and an electrode plate group folded in a zigzag manner so that the separators are sewn between the positive electrode sheets and the negative electrode sheets. It has been proposed (see, for example, Patent Document 1).
The positive electrode active material layer includes a positive electrode active material. In the case of a lithium ion secondary battery, for example, a lithium-containing transition metal oxide can be used as the positive electrode active material. Examples of the lithium-containing transition metal oxides, for example, Li x CoO z, Li x NiO z, Li x MnO z, Li x Co y Ni 1-y O z, Li x Co f V 1-f O z, Li x Ni 1-y M y O z (M = Ti, V, Mn, Fe), Li x Co a Ni b M c O z (M = Ti, Mn, Al, Mg, Fe, Zr), Li x Mn 2 O 4 , Li x Mn 2 (1-y) M 2y O 4 (M = Na, Mg, Sc, Y, Fe, Co, Ni, Ti, Zr, Cu, Zn, Al, Pb, Sb) It is done. However, the x value varies in the range of 0 ≦ x ≦ 1.2 depending on the charge / discharge of the battery. Also, 0 ≦ y ≦ 1, 0.9 ≦ f ≦ 0.98, 1.9 ≦ z ≦ 2.3, a + b + c = 1, 0 ≦ a ≦ 1, 0 ≦ b ≦ 1, 0 ≦ c <1 is there. These may be used alone or in combination of two or more.
The negative electrode active material layer includes a negative electrode active material. In the case of a lithium ion secondary battery, examples of the negative electrode active material include lithium, lithium alloy, intermetallic compound, carbon material, silicon (Si), silicon oxide (SiO x ), tin (Sn), and occlusion of lithium ions. A releasable organic compound, inorganic compound, metal complex, and organic polymer compound can be used. These may be used alone or in combination of two or more.
When the negative electrode active material contains at least one of Si, SiO x and Sn, the negative electrode active material layer may be a deposited film containing these elements.
Examples of the lithium salt include LiPF 6 , LiBF 4 , LiClO 4 , LiAlCl 4 , LiSbF 6 , LiSCN, LiCl, LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiN (CF 3 SO 2 ) 2 , Li 2. B 10 Cl 10 , LiN (C 2 F 5 SO 2 ) 2 , LiPF 3 (CF 3 ) 3 , and LiPF 3 (C 2 F 5 ) 3 can be used. These may be used alone or in combination of two or more. The lithium salt preferably contains at least LiPF 6 .
100 parts by weight of lithium cobaltate (LiCoO 2 ) as a positive electrode active material, 3 parts by weight of acetylene black as a conductive material, 7 parts by weight of polyvinylidene fluoride as a binder, and an appropriate amount of carboxymethylcellulose aqueous solution as a dispersion medium Were mixed to prepare a positive electrode mixture paste. This paste was applied to the entire surface of the Al vapor deposition film to form a coating layer having a width of 80 mm and a length of 1 m. Thereafter, the coating layer was dried and rolled with a roller until the thickness reached 70 μm to obtain a positive electrode active material layer.
It was obtained so that the current collector surfaces were in contact with each other with a folding axis passing through the center of the side parallel to the length direction of the electrode plate (side of 160 mm) and parallel to the side parallel to the width direction (side of 47 mm). The electrode plate was bent to obtain a negative electrode having a size of (80 mm + projection 3 mm) × 47 mm. At this time, as described above, since the positions of the protrusions are shifted in the opposite directions, they did not overlap each other.
The battery of the present invention includes at least one first electrode, at least one second electrode, and a strip-shaped separator. The separator constitutes a laminate having at least one first electrode housing portion and at least one second electrode housing portion that are folded in a zigzag manner and are alternately arranged. The laminated body has a first end surface on which at least one first bent portion is disposed and a second end surface on which at least one second bent portion is disposed. The first end face is located on the opposite side of the second end face. The first electrode housing part has an open part on the first end face side, and the second electrode housing part has an open part on the second end face side. A first electrode is accommodated in the first electrode accommodating portion, and the second electrode is accommodated in the second electrode accommodating portion. Each of the first electrode and the second electrode has two electrode parts including a current collector and an active material layer carried on one side thereof, and the two electrode parts are arranged such that the current collectors are in contact with each other. Has been placed. In at least one of the first electrode and the second electrode, one of the two electrode portions in contact with the current collector has a protrusion protruding toward the open portion of the end face as compared with the other . Projection includes said active material layer and the current collector. The first end surface includes a first terminal connected to the first electrode, and the second end surface includes a second terminal connected to the second electrode. The current collector contained in at least one of the first electrode and the second electrode has a thickness of 0.1 to 5 μm. Each of the first terminal and the second terminal is preferably made of a metal film. In addition, each of the first terminal and the second terminal preferably includes a lead.
In at least one of the first electrode and the second electrode, each of the two electrode portions, not preferable that the area is equal projections are provided.
The present invention also relates to a battery including two first electrodes, a second electrode, and a strip-shaped separator. The separator is folded in a zigzag manner to form a laminated body having two first electrode housing portions and one second electrode housing portion arranged therebetween. The laminate has a first end surface on which one first bent portion is disposed and a second end surface on which two second bent portions are disposed, and the first end surface is located on the opposite side of the second end surface. Yes. The first electrode housing part has an open part on the first end face side, and the second electrode housing part has an open part on the second end face side. The first electrode is accommodated in the first electrode accommodating portion, and the second electrode is accommodated in the second electrode accommodating portion. The first electrode has one electrode portion including a current collector and an active material layer carried on one surface thereof. The second electrode has two electrode portions including a current collector and an active material layer carried on one surface thereof, and the two electrode portions are arranged so that the current collectors are in contact with each other. Each of the first electrodes has an active material layer facing the active material layer of the second electrode via a separator. In the second electrode, one of the two electrode portions in contact with the current collector, than the other, has at least one projection projecting into the open portion side of the end surface, the projection, the and a and collector the active material layer. The first end surface includes a first terminal connected to the first electrode, and the second end surface includes a second terminal connected to the second electrode. The current collector contained in at least one of the first electrode and the second electrode has a thickness of 0.1 to 5 μm.
Comprising at least one first electrode, at least one second electrode, and a strip-shaped separator;
The separator constitutes a laminate having at least one first electrode housing portion and at least one second electrode housing portion, which are folded in a zigzag and are alternately arranged, and the laminate has at least 1 A first end surface provided with one first bent portion and a second end surface provided with at least one second bent portion, wherein the first end surface is located on the opposite side of the second end surface;
The first electrode housing portion has an open portion on the first end surface side, the second electrode housing portion has an open portion on the second end surface side, and the first electrode housing portion includes the first electrode housing portion. An electrode is housed in the second electrode housing portion, the second electrode is housed,
Each of the first electrode and the second electrode has two electrode parts including a current collector and an active material layer supported on one surface of the current collector, and the two electrode parts are formed of the current collector. It is arranged so that the electrical objects touch each other,
In at least one of the first electrode and the second electrode, at least one of the electrode portions has a protrusion protruding toward the open portion of the end face, and the protrusion includes a current collector and an active material layer. Including
The battery, wherein the first end surface includes a first terminal connected to the first electrode, and the second end surface includes a second terminal connected to the second electrode.
The battery according to claim 1, wherein each of the first terminal and the second terminal is made of a metal film.
In at least one of the first electrode and the second electrode, the two electrode portions include a current collector and a single electrode plate made of an active material layer supported on one surface of the current collector, The battery according to claim 1, wherein the battery is configured to bend so that surfaces of the current collector that do not carry the active material layer are in contact with each other.
When the one electrode plate is bent, the position of two sides parallel to the bending axis of the electrode plate is shifted in the length direction of the electrode plate, so that only one of the two electrode portions protrudes. The battery according to claim 3, wherein the portion is provided over the entire width direction of the electrode portion.
In at least one of the first electrode and the second electrode, the two electrode portions include two electrode plates each comprising a current collector and an active material layer carried on one surface of the current collector, The battery of Claim 1 comprised by laminating | stacking so that the surfaces which are not carry | supporting the active material layer of an electrical power collector may contact.
2. The battery according to claim 1, wherein, in at least one of the first electrode and the second electrode, each of the two electrode portions is provided with the protrusion having the same area.
The battery according to claim 1, wherein each of the first terminal and the second terminal includes a lead.
The battery according to claim 1, wherein a thickness of the current collector included in at least one of the first electrode and the second electrode is 0.1 μm to 5 μm.
The electrode housed in each electrode housing portion at both ends of the laminate is composed of a current collector and one electrode plate including an active material layer carried on one side of the current collector, and the active material layer The battery according to claim 1, which is opposed to an active material layer of an electrode accommodated in an adjacent electrode accommodating portion via the separator.
Comprising two first electrodes, a second electrode, and a strip-shaped separator;
The separator is folded in a zigzag manner to form a stacked body having two first electrode housing portions and one second electrode housing portion disposed between the first electrode housing portions, A first end surface provided with one first bent portion and a second end surface provided with two second bent portions, the first end surface being located on the opposite side of the second end surface;
The first electrode has one electrode portion including a current collector and an active material layer carried on one side of the current collector,
The second electrode has two electrode portions including a current collector and an active material layer carried on one side of the current collector, and the two electrode portions are arranged such that the current collector is in contact with each other. Are located in
Each of the first electrodes has an active material layer facing the active material layer of the second electrode through the separator,
At least one of the two electrode portions of the second electrode and the electrode portion of the first electrode has at least one protrusion that protrudes toward the open side of the end face, and the protrusion includes a current collector and an active portion. Including a material layer,
JP2006535882A 2005-05-10 2006-05-01 battery Expired - Fee Related JP3993223B2 (en)
JP2005137656 2005-05-10
PCT/JP2006/309096 WO2006120959A1 (en) 2005-05-10 2006-05-01 Battery
JP3993223B2 JP3993223B2 (en) 2007-10-17
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JP2006535882A Expired - Fee Related JP3993223B2 (en) 2005-05-10 2006-05-01 battery
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