JP2018142607A - Electrochemical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical device which is superior in productivity, and which allows a pre-doping state of a negative electrode to be uniformized.SOLUTION: An electrochemical device 100 comprises: a first electrode unit 101; a second electrode unit 102; a third electrode unit 103; a first lithium ion supplying source 104; a second lithium ion supplying source 105; a first sheet member 171; a second sheet member 172; and an electrolyte solution. The first lithium ion supplying source includes a first current collector composed of a piece of porous metal foil having a first principal face on a first electrode unit side. The second lithium ion supplying source includes a second current collector composed of a piece of porous metal foil having a third principal face on a second electrode unit side. The first sheet member separates the first lithium ion supplying source from the third electrode unit and arranged so that a lithium ion is allowed to pass therethrough. The second sheet member separates the second lithium ion supplying source from the third electrode unit and arranged so that a lithium ion is allowed to pass therethrough.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrochemical device composed of a plurality of electrode units.

  High-capacity capacitors are increasingly used in fields that require repeated charging and discharging with large power, such as energy regeneration and load leveling. Conventionally, electric double layer capacitors have been widely used as large-capacity capacitors, but in recent years, the use of lithium ion capacitors having a high energy density has been studied.

  Lithium ion capacitors require pre-doping in which lithium ions are previously doped into the negative electrode, but it is important to make the pre-doped state of the negative electrode uniform in order to stably use the lithium ion capacitor for a long period of time.

  Here, pre-doping of lithium ions is performed by immersing metallic lithium electrically connected to the negative electrode in the electrolytic solution. Since lithium ions move through the electrolyte and reach the negative electrode, the pre-doping state is affected by the positional relationship between the negative electrode and the lithium ion supply source.

  For example, Patent Document 1 discloses a configuration in which lithium ions are supplied to the negative electrode by disposing a lithium ion supply source between a plurality of electrode units constituting the cell and on the outermost part.

International Publication No. 2006/111068

  However, in the configuration described in Patent Document 1, it is necessary to produce three types of lithium ion supply sources arranged at the uppermost portion, the lowermost portion, and between the electrode units, and there is a problem that the types of components and the number of components are large. There is. In addition, a porous metal foil can be used as a current collector for a lithium ion supply source, and the doping amount of lithium ions can be adjusted by the pore diameter and the aperture ratio, but there is a problem with long-term reliability.

  In view of the circumstances as described above, an object of the present invention is to provide an electrochemical device that is excellent in productivity and can make the pre-doped state of the negative electrode uniform.

To achieve the above object, an electrochemical device according to an aspect of the present invention includes a first electrode unit, a second electrode unit, a third electrode unit, a first lithium ion supply source, 2 lithium ion supply sources, a first sheet member, a second sheet member, and an electrolytic solution.
In the first electrode unit, positive electrodes and negative electrodes are alternately stacked via separators.
In the second electrode unit, positive electrodes and negative electrodes are alternately stacked via separators.
In the third electrode unit, positive electrodes and negative electrodes are alternately stacked via separators, and are positioned between the first electrode unit and the second electrode unit.
The first lithium ion supply source is disposed between the first electrode unit and the third electrode unit, the first main surface on the first electrode unit side, and the third electrode unit. A first current collector that is a porous metal foil having a second main surface on the side.
The second lithium ion supply source is disposed between the second electrode unit and the third electrode unit, and has a third main surface on the second electrode unit side, and the third electrode unit. And a second current collector that is a porous metal foil having a fourth main surface on the side.
The first sheet member is disposed between the first lithium ion supply source and the third electrode unit, separates the first lithium ion supply source and the third electrode unit, and releases lithium ions. Transparent.
The second sheet member is disposed between the second lithium ion supply source and the third electrode unit, separates the second lithium ion supply source and the third electrode unit, and releases lithium ions. Transparent.
The electrolyte solution includes the first electrode unit, the second electrode unit, the third electrode unit, the first lithium ion supply source, the second lithium ion supply source, and the first sheet member. And the said 2nd sheet | seat member is immersed.
The negative electrode included in the first electrode unit, the second electrode unit, and the third electrode unit is attached to the first metal lithium affixed to the first main surface and the third main surface. The second metal lithium is pre-doped with lithium ions.

  According to this configuration, a large amount of lithium ions released from the first lithium ion supply source is supplied to the first electrode unit facing the first metal lithium, and a part thereof is the porous metal foil. Is supplied to the third electrode unit through the through hole of the current collector. In addition, a large amount of lithium ions released from the second lithium ion supply source is supplied to the second electrode unit facing the second metal lithium, and a part of the second current collector is a porous metal foil. Is supplied to the third electrode unit through the through hole. The amount of lithium ions supplied from the first lithium ion source to the third electrode unit is less than the amount of lithium ions supplied to the first electrode unit, and the third electrode from the second lithium ion source The amount of lithium ions supplied to the unit is less than the amount of lithium ions supplied to the second electrode unit, but the third electrode unit includes a first lithium ion source and a second lithium ion source. Since lithium ions are supplied from both, the pre-doping amount of lithium ions can be made approximately the same among the first electrode unit, the second electrode unit, and the third electrode unit. Further, by providing the first sheet member and the second sheet member, between the first lithium ion supply source and the third electrode unit and between the second lithium ion supply source and the third electrode unit. Lithium ions that are separated and transmitted through the first current collector and the second current collector can be uniformly distributed in the negative electrode included in the third electrode unit.

  The first sheet member and the second sheet member may be separators.

  By using the separator as the first sheet member and the second sheet member, it is possible to reduce the types of components constituting the electrochemical device.

  The first sheet member and the second sheet member may be configured by laminating a plurality of separators.

  By stacking a plurality of separators, it is possible to further separate the first lithium ion supply source and the third electrode unit and the second lithium ion supply source and the third electrode unit.

  The thickness of the first sheet member may be 25 μm or more, and the thickness of the second sheet member may be 25 μm or more.

  By setting the thickness of the first sheet member and the second sheet member to 25 μm or more, the first sheet member and the second sheet member improve the diffusibility of lithium ions, and the distribution of lithium ions in the negative electrode is uniform. It is possible to

  In the first sheet member, the distance between the negative electrode closest to the first lithium ion supply source among the negative electrodes included in the third electrode unit and the first current collector is 50 μm or more. The first lithium ion supply source and the negative electrode are separated from each other, and the second sheet member includes a negative electrode closest to the second lithium ion supply source among the negative electrodes provided in the third electrode unit. The second lithium ion supply source and the negative electrode may be separated so that the distance between the second current collectors is 50 μm or more.

  By making the total thickness of the separator and the first sheet member or the second sheet member included in the third electrode unit 50 μm or more, the diffusibility in the main surface direction of lithium ions is improved, and the lithium ions in the negative electrode It is possible to make the distribution uniform.

  The positive electrode included in the first electrode unit, the second electrode unit, and the third electrode unit includes a positive electrode current collector that is a porous metal foil, a positive electrode active material, and both front and back surfaces of the positive electrode current collector The negative electrode provided in the first electrode unit, the second electrode unit, and the third electrode unit includes a negative electrode current collector that is a porous metal foil, and a negative electrode active material. And a negative electrode active material layer laminated on both front and back surfaces of the negative electrode current collector.

  According to this configuration, the lithium ions released from the first lithium ion supply source and the second lithium ion supply source can move in each electrode unit without being blocked by the positive electrode, the negative electrode, and the separator, It becomes possible to make the dope amount of lithium ions uniform in the electrode unit.

  The first electrode unit, the second electrode unit, and the third electrode unit may have the same thickness.

  According to this configuration, the electrode units having the same structure can be used as the first electrode unit, the second electrode unit, and the third electrode unit, and the doping amount of lithium ions is uniform in each electrode unit. Can be realized.

  The electrochemical device may be a lithium ion capacitor.

  As described above, according to the present invention, it is possible to provide an electrochemical device that is excellent in productivity and can make the pre-doped state of the negative electrode uniform.

1 is a perspective view of an electrochemical device according to an embodiment of the present invention. It is sectional drawing of the same electrochemical device. It is sectional drawing of the electrode unit with which the same electrochemical device is provided. It is an enlarged view of the same electrochemical device. It is a schematic diagram of the 1st sheet | seat member with which the same electrochemical device is provided. It is a schematic diagram of the 2nd sheet member with which the same electrochemical device is provided. It is a schematic diagram which shows the aspect of the lithium ion pre dope in the same electrochemical device. It is a schematic diagram which shows the aspect of the diffusion of lithium ion when the 1st sheet member does not exist. It is a schematic diagram which shows the aspect of a lithium ion diffusion when a 1st sheet | seat member exists. It is a table | surface which shows the number of separators and cycle life of the electrochemical device which concerns on the Example of this invention.

  The electrochemical device according to this embodiment will be described.

[Structure of electrochemical device]
FIG. 1 is a perspective view of an electrochemical device 100 according to this embodiment, and FIG. 2 is a cross-sectional view of the electrochemical device 100. 2 is a cross-sectional view taken along line AA in FIG.

  The electrochemical device 100 is an electrochemical device that requires pre-doping of lithium ions, and can be a lithium ion capacitor. The electrochemical device 100 may be another electrochemical device that requires lithium ion pre-doping, such as a lithium ion battery. In the following description, it is assumed that the electrochemical device 100 is a lithium ion capacitor.

  As shown in FIGS. 1 and 2, the electrochemical device 100 includes a first electrode unit 101, a second electrode unit 102, a third electrode unit 103, a first lithium ion supply source 104, a second lithium ion supply source 105, An exterior film 106, a positive electrode terminal 107, a negative electrode terminal 108, a first sheet member 171 and a second sheet member 172 are provided.

  Hereinafter, a laminated body of the first electrode unit 101, the second electrode unit 102, the third electrode unit 103, the first lithium ion supply source 104, the second lithium ion supply source 105, the first sheet member 171 and the second sheet member 172. Is an electrode body 109.

  Each of the first electrode unit 101, the second electrode unit 102, and the third electrode unit 103 is a unit capable of storing electricity. The first electrode unit 101, the second electrode unit 102, and the third electrode unit 103 may have the same structure.

  FIG. 3 is a schematic diagram of an electrode unit 110 that can be used as the first electrode unit 101, the second electrode unit 102, and the third electrode unit 103. As shown in the figure, the electrode unit 110 includes a positive electrode 120, a negative electrode 130, and a separator 140.

  The positive electrode 120 includes a positive electrode current collector 121 and a positive electrode active material layer 122. The positive electrode current collector 121 is a porous metal foil in which a large number of through holes are formed, for example, an aluminum foil. The thickness of the positive electrode current collector 121 is, for example, 0.03 mm.

  The positive electrode active material layer 122 is formed on both the front and back surfaces of the positive electrode current collector 121. The positive electrode active material layer 122 may be a mixture of a positive electrode active material and a binder resin, and may further include a conductive additive. The positive electrode active material is a material that can adsorb lithium ions and anions in the electrolytic solution, such as activated carbon or polyacene carbide.

  The binder resin is a synthetic resin that joins the positive electrode active material. For example, styrene butadiene rubber, polyethylene, polypropylene, aromatic polyamide, carboxymethyl cellulose, fluorine rubber, polyvinylidene fluoride, isoprene rubber, butadiene rubber, and ethylene propylene rubber. Etc. may be used.

  The conductive auxiliary agent is a particle made of a conductive material, and improves the conductivity between the positive electrode active materials. Examples of the conductive assistant include carbon materials such as graphite and carbon black. These may be single and multiple types may be mixed. The conductive auxiliary agent may be a metal material or a conductive polymer as long as it is a conductive material.

  The negative electrode 130 includes a negative electrode current collector 131 and a negative electrode active material layer 132. The negative electrode current collector 131 is a porous metal foil in which a large number of through holes are formed, for example, a copper foil. The thickness of the negative electrode current collector 131 is, for example, 0.015 mm.

  The negative electrode active material layer 132 is formed on both the front and back surfaces of the negative electrode current collector 131. The negative electrode active material layer 132 may be a mixture of a negative electrode active material and a binder resin, and may further include a conductive additive. The negative electrode active material is a material that can occlude lithium ions in the electrolyte, such as non-graphitizable carbon (hard carbon), carbon-based materials such as graphite and soft carbon, alloy-based materials such as Si and SiO, or those These composite materials can be used.

  The binder resin is a synthetic resin that joins the negative electrode active material. For example, styrene butadiene rubber, polyethylene, polypropylene, aromatic polyamide, carboxymethyl cellulose, fluorine rubber, polyvinylidene fluoride, isoprene rubber, butadiene rubber, and ethylene propylene rubber. Etc. may be used.

  The conductive auxiliary agent is a particle made of a conductive material, and improves the conductivity between the negative electrode active materials. Examples of the conductive assistant include carbon materials such as graphite and carbon black. These may be single and multiple types may be mixed. The conductive auxiliary agent may be a metal material or a conductive polymer as long as it is a conductive material.

  Separator 140 separates positive electrode 120 and negative electrode 130 and transmits ions contained in the electrolytic solution. The separator 140 can be a woven fabric, a nonwoven fabric, a synthetic resin microporous film, or the like, and can be made of, for example, an olefin resin as a main material.

  As shown in FIG. 3, the positive electrode 120, the negative electrode 130, and the separator 140 are stacked so that the positive electrode 120 and the negative electrode 130 are alternately arranged with the separator 140 interposed therebetween. It is configured as follows. The number of stacked layers of the positive electrode 120 and the negative electrode 130 is not particularly limited. For example, the positive electrode 120 can have nine layers, the negative electrode 130 can have ten layers, and the like.

  The electrode unit 110 having the above structure can be used as the first electrode unit 101, the second electrode unit 102, and the third electrode unit 103. The positive electrode current collector 121 of each electrode unit is electrically connected to the positive electrode terminal 107 directly or via wiring (not shown), and the negative electrode current collector 131 of each electrode unit is electrically connected to the negative electrode terminal 108 directly or via wiring (not shown). Connected.

  The first lithium ion supply source 104 is disposed between the first electrode unit 101 and the third electrode unit 103, and supplies lithium ions to the negative electrode 130 of each electrode unit. FIG. 4 is an enlarged view of the electrode body 109. As shown in the figure, the first lithium ion supply source 104 includes a lithium current collector 151 and a metallic lithium 152.

  The lithium current collector 151 is a porous metal foil in which a large number of through holes (h in the figure) are formed, and is a copper foil, for example. The through hole h is formed through the lithium current collector 151, and the diameter of the hole can be about several tens to several hundreds μm. The lithium current collector 151 is electrically connected to the negative electrode current collector 131 of each electrode unit directly or via the negative electrode terminal 108.

  As shown in FIG. 4, of the main surfaces of the lithium current collector 151, the surface on the first electrode unit 101 side is a first main surface 151 a, and the surface on the third electrode unit 103 side is a second main surface. 151b.

  The metallic lithium 152 is affixed to the first main surface 151a by pressure bonding or the like. The metal lithium 152 preferably has a uniform thickness over the entire surface of the first main surface 151a.

  The second lithium ion supply source 105 is disposed between the second electrode unit 102 and the third electrode unit 103, and supplies lithium ions to the negative electrode 130 of each electrode unit. As shown in FIG. 4, the second lithium ion supply source 105 includes a lithium current collector 161 and a metal lithium 162.

  The lithium current collector 161 is a porous metal foil in which a large number of through holes (h in the figure) are formed, and is a copper foil, for example. The through hole h is formed so as to penetrate the lithium current collector 161, and the hole diameter can be about several tens to several hundreds of μm. The lithium current collector 161 is electrically connected to the negative electrode current collector 131 of each electrode unit directly or via the negative electrode terminal 108.

  As shown in FIG. 4, among the main surfaces of the lithium current collector 161, the surface on the second electrode unit 102 side is the third main surface 161 a, and the surface on the third electrode unit 103 side is the fourth main surface. 161b.

  The metallic lithium 162 is attached to the third main surface 161a by pressure bonding or the like. It is preferable that the metallic lithium 162 has a uniform thickness over the entire third main surface 161a.

  The first sheet member 171 is disposed between the first lithium ion supply source 104 and the third electrode unit 103, separates the first lithium ion supply source 104 and the third electrode unit 103, and transmits lithium ions. The first sheet member 171 only needs to have ion permeability, and can be a woven fabric, a nonwoven fabric, a synthetic resin microporous membrane, or the like, for example, an olefin resin as a main material. Can do. The first sheet member 171 may be a sheet member made of the same material as the separator 140.

  FIG. 5 is a schematic diagram showing the first sheet member 171. Although the thickness of the 1st sheet | seat member 171 is not specifically limited, 25 micrometers or more are suitable. The first sheet member 171 may be a laminate of a plurality of sheet members made of the same material as the separator 140.

  As shown in FIG. 5, a separator 140 is provided on the outermost layer of the third electrode unit 103. Therefore, by providing the first sheet member 171, the distance between the negative electrode 130 closest to the first lithium supply source 104 in the third electrode unit 103 and the lithium current collector 151 (the first separation in FIG. 5). The distance t1) is the sum of the thicknesses of the first sheet member 171 and the separator 140. The first separation distance t1 is preferably 50 μm or more.

  The second sheet member 172 is disposed between the second lithium ion supply source 105 and the third electrode unit 103, separates the second lithium ion supply source 105 and the third electrode unit 103, and transmits lithium ions. The second sheet member 172 only needs to have ion permeability, and can be a woven fabric, a nonwoven fabric, a synthetic resin microporous membrane, or the like, for example, an olefin resin as a main material. Can do. The second sheet member 172 may be a sheet member made of the same material as the separator 140.

  FIG. 6 is a schematic diagram showing the second sheet member 172. The thickness of the second sheet member 172 is not particularly limited, but is preferably 25 μm or more. The second sheet member 172 may be a laminate of a plurality of sheet members made of the same material as the separator 140.

  As shown in FIG. 6, a separator 140 is provided on the outermost layer of the third electrode unit 103. Therefore, by providing the second sheet member 172, the distance between the negative electrode 130 closest to the second lithium supply source 105 of the third electrode unit 103 and the lithium current collector 161 (the second separation distance in FIG. 6). t2) is the sum of the thicknesses of the second sheet member 172 and the separator 140. The second separation distance t2 is preferably 50 μm or more.

  The exterior film 106 forms a storage space for storing the electrode body 109 and the electrolytic solution. The exterior film 106 is a laminate film in which a metal foil such as an aluminum foil and a resin are laminated, and is fused and sealed around the electrode body 109. Instead of the exterior film 106, a can-like member that can seal the accommodation space may be used.

Although the electrolyte solution accommodated in the accommodation space together with the electrode body 109 is not particularly limited, for example, a solution containing LiPF ₆ or the like as a solute can be used.

  The positive electrode terminal 107 is an external terminal of the positive electrode 120 and is electrically connected to the positive electrode 120 of each electrode unit. As shown in FIG. 1, the positive terminal 107 is drawn from between the exterior films 106 to the outside of the accommodation space. The positive electrode terminal 107 may be a foil or a wire made of a conductive material.

  The negative electrode terminal 108 is an external terminal of the negative electrode 130 and is electrically connected to the negative electrode 130 of each electrode unit. As shown in FIG. 1, the negative electrode terminal 108 is drawn from between the exterior films 106 to the outside of the accommodation space. The negative electrode terminal 108 may be a foil or a wire made of a conductive material.

[About lithium ion pre-doping]
In the manufacturing stage of the electrochemical device 100, when the electrode body 109 is immersed in the electrolytic solution in a state where the lithium current collector 151, the lithium current collector 161 and the negative electrode current collector 131 are electrically connected, the metallic lithium 152 Then, the lithium metal 162 is dissolved and lithium ions are released into the electrolyte. The lithium ions move in the electrolytic solution and are doped (pre-doped) into the negative electrode active material layer 132 of the negative electrode 130 included in each electrode unit.

  FIG. 7 is a schematic diagram showing pre-doping of lithium ions. As shown in the figure, most of the lithium ions released from the metal lithium 152 are doped into the first electrode unit 101 facing the metal lithium 152 (arrow A in the figure). A part of the lithium ions diffuses through the through hole h of the lithium current collector 151 and the first sheet member 171, and the third electrode unit 103 is doped with a predetermined amount (arrow B in the figure).

  Since the metallic lithium 152 and the third electrode unit 103 are separated by the lithium current collector 151 except for the through hole h, the amount of lithium ions doped from the metallic lithium 152 into the third electrode unit 103 is The amount of lithium ions doped from the metallic lithium 152 into the first electrode unit 101 is smaller.

  Further, as shown in FIG. 7, most of the lithium ions released from the metallic lithium 162 are doped into the second electrode unit 102 facing the metallic lithium 162 (arrow C in the figure). Further, a part of the lithium ions diffuses through the through hole h of the lithium current collector 161 and the second sheet member 172, and the third electrode unit 103 is doped with a predetermined amount (arrow D in the figure).

  Since the metallic lithium 162 and the third electrode unit 103 are separated by the lithium current collector 161 except for the through hole h, the amount of lithium ions doped from the metallic lithium 162 to the third electrode unit 103 is This is less than the amount of lithium ions doped from the metallic lithium 162 into the second electrode unit 102.

  However, since lithium ions are supplied to the third electrode unit 103 from both the metal lithium 152 and the metal lithium 162, the amount of pre-doped lithium ions is equal to that of the first electrode unit 101 and the second electrode unit 102. . Thereby, the dope amount of lithium ions becomes uniform among the first electrode unit 101, the second electrode unit 102, and the third electrode unit 103, and the long-term stability of the electrochemical device 100 can be ensured.

  Further, since the first lithium ion supply source 104 and the second lithium ion supply source 105 have the same structure, it is not necessary to make both separately, and the manufacturing cost can be reduced.

  Further, as described above, the first sheet member 171 is provided between the first lithium ion supply source 104 and the third electrode unit 103, and between the second lithium ion supply source 105 and the third electrode unit 103. A second sheet member 172 is provided.

  8 and 9 are schematic views showing the effects of the first sheet member 171. FIG. As shown in FIG. 8, if the first sheet member 171 is not provided, the lithium current collector 151 and the negative electrode 130 approach each other, and lithium ions (which reach the third electrode unit 103 through the through hole h) ( An arrow in the figure has a non-uniform distribution in the negative electrode 130.

  In contrast, when the first sheet member 171 is provided as shown in FIG. 9, the lithium current collector 151 and the negative electrode 130 are separated from each other, and lithium ions (that reach the third electrode unit 103 through the through holes h) ( The arrows in the figure are uniformly distributed in the main surface direction of the negative electrode 130.

  Similarly, for the second sheet member 172, the lithium current collector 162 and the negative electrode 130 are separated from each other, and the distribution of lithium ions in the main surface direction of the negative electrode 130 is made uniform.

  Thereby, the distribution of lithium ions in the negative electrode 130 of the third electrode unit 130 becomes uniform, and the long-term stability of the electrochemical device 100 can be further ensured.

  As described above, the metal lithium 152 and the metal lithium 162 are dissolved in the pre-dope, and the metal lithium 152 and the metal lithium 162 do not exist when the electrochemical device 100 is used. However, the arrangement of the metallic lithium before pre-doping can be determined by the metallic lithium residue and the like present in the lithium current collector 151 and the lithium current collector 161.

[Modification]
As described above, the electrochemical device 100 includes the first electrode unit 101, the second electrode unit 102, the third electrode unit 103, the first lithium ion supply source 104 and the second lithium ion supply source 105, the first sheet member 171 and the first sheet member 171. An electrode body 109 in which two sheet members 172 are stacked is provided. Here, the electrochemical device 100 may have a structure in which a plurality of electrode bodies 109 are stacked and accommodated in an accommodation space. Even in this case, it is possible to make the doping amount of lithium ions uniform between the electrode units provided in the respective electrode bodies 109.

  Moreover, in the above-mentioned embodiment, although the thickness of one separator was 25 micrometers, it is good also as the same thickness by using several separators thinner than it.

  Metal lithium was affixed to a copper foil having a through-hole (hole diameter: 100 μm, opening ratio: 30%) to produce a lithium ion supply source. The amount of metallic lithium was such that the negative electrode SOC (state of charge) was about 60%.

  The positive electrode and the negative electrode were laminated via a separator to produce the electrode unit described above. A lithium ion supply source and a separator (a first sheet member and a second sheet member) were arranged between the electrode units, and three electrode units were laminated to produce the above-described electrode body. A positive electrode terminal and a negative electrode terminal were connected to the electrode body and sealed in a laminate film together with the electrolyte. As a result, a lithium ion capacitor having a capacity of 2000F was manufactured. A plurality of types of lithium ion capacitors having different numbers of separators inserted between the electrode unit and the lithium ion supply source were prepared.

  About the produced lithium ion capacitor, the 100C cycle test was implemented in the high temperature environment, and the cycle life was measured. FIG. 10 is a table showing the cycle life of various lithium ion capacitors. “Cycle life” is the number of cycles when the DCR (direct current resistance) is 200% of the initial ratio.

  The “number of separators” is the number of separators used as the first sheet member and the second sheet member, and the thickness of one separator is 25 μm. The “current collector-closest negative electrode distance” is the sum of the thicknesses of the separators included in the first sheet member or the second sheet member and the electrode unit.

  As shown in the figure, when the number of separators was 0, the cycle life was 44800 cycles. On the other hand, when the number of separators was 1, the cycle life was improved to 53400 cycles. Similarly, it was confirmed that the cycle life was improved when the number of separators was similarly increased.

  As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, Of course, a various change can be added.

DESCRIPTION OF SYMBOLS 100 ... Electrochemical device 101 ... 1st electrode unit 102 ... 2nd electrode unit 103 ... 3rd electrode unit 104 ... 1st lithium ion supply source 105 ... 2nd lithium ion supply source 106 ... Exterior film 109 ... Electrode body 110 ... Electrode Unit 120 ... Positive electrode 121 ... Positive electrode current collector 122 ... Positive electrode active material layer 130 ... Negative electrode 131 ... Negative electrode current collector 132 ... Negative electrode active material layer 140 ... Separator 151, 161 ... Lithium current collector 152, 162 ... Metal lithium 171 ... 1st sheet member 172 ... 2nd sheet member

Claims (8)

A first electrode unit in which positive and negative electrodes are alternately stacked via separators;
A second electrode unit in which positive and negative electrodes are alternately stacked via separators;
A positive electrode and a negative electrode are alternately stacked via a separator, and a third electrode unit positioned between the first electrode unit and the second electrode unit;
The first electrode unit is disposed between the first electrode unit and the third electrode unit, and has a first main surface on the first electrode unit side and a second main surface on the third electrode unit side. A first lithium ion source comprising a first current collector that is a porous metal foil;
It is arrange | positioned between the said 2nd electrode unit and the said 3rd electrode unit, and has the 3rd main surface by the side of the 2nd electrode unit, and the 4th main surface by the side of the 3rd electrode unit. A second lithium ion source comprising a second current collector that is a porous metal foil;
A first sheet member that is disposed between the first lithium ion supply source and the third electrode unit, separates the first lithium ion supply source and the third electrode unit, and transmits lithium ions. When,
A second sheet member disposed between the second lithium ion supply source and the third electrode unit, separating the second lithium ion supply source and the third electrode unit and transmitting lithium ions; When,
The first electrode unit, the second electrode unit, the third electrode unit, the first lithium ion supply source, the second lithium ion supply source, the first sheet member and the second electrode unit An electrolyte solution in which the sheet member is immersed,
The negative electrode included in the first electrode unit, the second electrode unit, and the third electrode unit is attached to the first metal lithium attached to the first main surface and the third main surface. An electrochemical device in which lithium ions are pre-doped from the formed second metal lithium. The electrochemical device according to claim 1,
The electrochemical device according to claim 1, wherein the first sheet member and the second sheet member are separators. The electrochemical device according to claim 2,
An electrochemical device in which the first sheet member and the second sheet member are configured by laminating a plurality of separators. The electrochemical device according to any one of claims 1 to 3,
The thickness of the first sheet member is 25 μm or more,
The electrochemical device wherein the thickness of the second sheet member is 25 μm or more. The electrochemical device according to any one of claims 1 to 4,
In the first sheet member, the distance between the negative electrode closest to the first lithium ion supply source among the negative electrodes included in the third electrode unit and the first current collector is 50 μm or more. And separating the first lithium ion source and the negative electrode,
In the second sheet member, a distance between the negative electrode closest to the second lithium ion supply source among the negative electrodes included in the third electrode unit and the second current collector is 50 μm or more. And an electrochemical device for separating the second lithium ion supply source from the negative electrode. The electrochemical device according to any one of claims 1 to 5,
The positive electrode included in the first electrode unit, the second electrode unit, and the third electrode unit includes a positive electrode current collector that is a porous metal foil, a positive electrode active material, and both front and back surfaces of the positive electrode current collector A positive electrode active material layer laminated on
The negative electrodes included in the first electrode unit, the second electrode unit, and the third electrode unit include a negative electrode current collector that is a porous metal foil, and a negative electrode active material, and both front and back surfaces of the negative electrode current collector An electrochemical device comprising a negative electrode active material layer laminated on a substrate. The electrochemical device according to any one of claims 1 to 6,
The electrochemical device, wherein the first electrode unit, the second electrode unit, and the third electrode unit have the same thickness. The electrochemical device according to any one of claims 1 to 7,
An electrochemical device that is a lithium ion capacitor.

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