KR101846748B1 - Method for continuous preparation of positive electrode for all solid battery - Google Patents

Abstract

The present invention relates to a method for a continuous preparation method of a positive electrode for an all solid battery, and more specifically, to a method for a continuous preparation method of a positive electrode for an all solid battery, which forms a reinforcing layer including a through-hole first on a current collector, and forms a positive electrode layer by coating the through-hole with positive electrode slurry to continuously manufacture a positive electrode. Therefore, the alignment between the reinforcing layer and the positive electrode layer compared to a conventional process is very good, thereby preventing the occurrence of short circuit of the battery and greatly improving the energy density.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for continuously manufacturing a positive electrode for a solid-

More particularly, the present invention relates to a method for continuously manufacturing a positive electrode for a full-solid battery, and more particularly, to a method for continuously manufacturing a positive electrode for a full-solid battery, comprising: forming a reinforcing layer including a through- The present invention relates to a method for continuously manufacturing a positive electrode for an all-solid-state battery, wherein the positive electrode layer and the reinforcing layer are aligned with each other to prevent short-circuiting of the battery due to the difference in area between electrodes,

A secondary battery is a battery in which chemical energy and electrical energy are converted and recharged and discharged repeatedly through chemical reaction of oxidation and reduction. In general, the secondary battery includes four basic elements: anode, cathode, separator, and electrolyte. The positive electrode and the negative electrode are collectively referred to as an electrode, and among the constituent elements of the electrode material, a material that actually causes a reaction may be referred to as an active material.

 A typical lithium ion secondary battery uses an electrolyte including a liquid electrolyte and a liquid. However, liquid electrolytes are volatile, and there is a risk of explosion and thermal stability is also deteriorated.

 On the other hand, all solid state batteries using a solid electrolyte have low explosion risk and excellent thermal stability. In addition, a high operating voltage can be achieved by stacking electrodes with a bi-polar plate to allow serial connection. In this case, a higher energy density can be achieved than in a parallel connection method of a liquid electrolyte-applied battery.

As a method of stacking the batteries, generally, there is a parallel type and a serial type. In the parallel type, the positive electrode and the negative electrode are laminated with the electrode material of the same polarity positioned on both sides of the current collector. In the series method, a bipolar electrode having a positive electrode composite material on one surface of a current collector (bipolar plate) and a negative electrode composite material on the opposite surface is stacked.

 Here, the positive electrode mixture refers to a layer containing at least a positive electrode active material and further containing a conductive material, a binder and an electrolyte. Likewise, the negative electrode mixture refers to a layer containing at least an anode active material and further containing a conductive material, a binder and an electrolyte.

Unlike a battery using a conventional liquid electrolyte, a problem of contact between the electrode and the electrolyte is very large in forming the entire solid electrolyte. Since all solid-state batteries transmit lithium ions through solid-solid contact, separate pressurization or heat treatment processes between the electrodes and the electrolyte are essential to improve the contact between the electrodes and the electrolyte when stacking the batteries.

In particular, as the pressing force is increased, the contact between the electrode and the electrolyte is improved to improve the battery characteristics. However, in this case, a short circuit occurs more frequently in the battery. Also, in the case of a laminated battery other than a single battery, a short circuit of the battery due to stress unevenness due to area mismatch occurs more frequently.

Korean Unexamined Patent Publication No. 10-1577881 discloses a bipolar pre-solid battery in which a reinforcing layer is disposed between an end of an electrode active material layer and a surface of a current collector. However, there is a problem in that energy loss occurs due to reduced anode current collecting area. This is because cracks are frequently generated in the solid electrolyte layer at the anode / electrolyte boundary due to the difference in area between the anode and the solid electrolyte membrane rather than cracks in the current collector, so that the limit of preventing the battery short circuit at the thickness of 50 탆 or less of the solid electrolyte layer .

As described above, the entire solid-state battery is mainly caused by the difference in area between the positive electrode and the negative electrode, and cracks and short-circuiting occur mainly in the solid electrolyte layer contacting the positive electrode interface portion when the battery is pressurized. Therefore, it is required to develop a technique for solving the problem of battery short circuit of the all solid battery.

Korean Patent Publication No. 10-1577881

In order to solve the problems as described above, the present invention is characterized in that a reinforcing layer including through-holes having the same size as the anode area is first formed on the current collector, and then the positive electrode slurry is coated on the through- It was found that the alignment of the reinforcing layer and the anode layer with respect to the conventional process is very excellent, thereby preventing the short circuit of the battery due to the difference in area between the electrodes and greatly improving the stability and energy density of the battery.

Accordingly, it is an object of the present invention to provide a method for continuously manufacturing a positive electrode for an all-solid-state battery in which stability and energy density of a battery are greatly improved.

According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising: attaching a mask layer and a reinforcing layer including a plurality of through holes on one surface of a current collector; Coating a positive electrode slurry on the through hole with one surface of the current collector to form a positive electrode layer; Removing the mask layer; And a step of forming a positive electrode layer on the current collector by sputtering the current collector to obtain a positive electrode having a structure in which the reinforcing layer surrounds the positive electrode layer, to provide.

The method for continuously manufacturing the positive electrode for a full-solid battery according to the present invention is characterized in that a positive electrode layer is formed by first forming a reinforcing layer including through-holes having the same size as the anode area on the current collector, The process can be easily performed by manufacturing the positive electrode continuously, and the alignment of the reinforcing layer and the positive electrode layer is very excellent, thereby preventing the short circuit of the battery due to the difference in area between the electrodes and greatly improving the energy density of the battery.

Also, by making the entire solid battery using the same, the interface between the anode layer and the solid electrolyte layer can be densely formed to prevent cracking of the solid electrolyte layer and to prevent a short circuit in the battery.

FIG. 1 is a schematic view illustrating a method of manufacturing a positive electrode for a full-solid battery according to a first embodiment of the present invention.
FIG. 2 is a process diagram illustrating a method of manufacturing a positive electrode for a full-solid battery of Comparative Example 1 according to the present invention.
FIG. 3 is a photograph of the boundary between the anode and the solid electrolyte membrane taken from the top in the all-solid-state cell manufactured using the anode prepared in Example 1 and Comparative Example 1 according to the present invention.
4 is a SEM photograph showing a cross-section of a pre-solid battery manufactured using the anode for all solid-state batteries manufactured in Example 1 according to the present invention.
FIG. 5 is a graph showing the charging / discharging of all solid-state cells manufactured using the positive electrode according to Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail with reference to one embodiment.

The present invention is characterized in that a reinforcing layer 2 is first formed on a current collector 1 and then a positive electrode layer 4 is formed so that the structure of the positive electrode layer 4 and the reinforcing layer 2 is very aligned, And a method of manufacturing the anode.

More specifically, the method for continuously manufacturing a positive electrode for a full-solid battery of the present invention comprises the steps of: attaching a reinforcing layer 2 and a mask layer 3 including a plurality of through holes to one surface of a current collector 1; Coating a positive electrode slurry on the through hole with a surface of the current collector 1 to form a positive electrode layer 4; Removing the mask layer (3); And a positive electrode layer (4) formed on the current collector (1) by punching the current collector (1), and a positive electrode having a structure in which the reinforcing layer (2) surrounds the positive electrode layer ;

According to a preferred embodiment of the present invention, the reinforcing layer 2 and the mask layer 3 may each be in the form of a film including a plurality of through holes. At this time, the plurality of through holes may be spaced apart at a predetermined distance. The through hole may be circular or rectangular, but is not limited thereto.

According to a preferred embodiment of the present invention, the reinforcing layer (2) having through holes of the same size can be attached to the current collector (1) by a heat fusion method. That is, in Comparative Example 1, after the anode layer 4 was formed, the anode layer 4 was surrounded by the reinforcing layer 2, but in the present invention, The reinforcing layer 2 and the mask layer 3 including a plurality of through holes can be attached first. If the reinforcing layer 2 and the mask layer 3 are attached to the current collector 1, a positive electrode having a very good alignment between the reinforcing layer and the positive electrode layer can be obtained. Such an anode can minimize the stress uniformity in the subsequent cell pressurization process so that the thin electrolyte membrane can be maintained without cracks even at high pressure.

In addition, in the positive electrode for an all-solid-state battery of the present invention, the reinforcing layer 2 prevents an electrolyte membrane from being broken due to stress unevenness as an insulator between the current collector 1 and the positive electrode layer 4, And serves to prevent short-circuiting of the cell due to contact between the anode and the cathode.

In addition, the mask layer 3 may be formed in the same position as the reinforcing layer 2 with the same area so that the reinforcing layer and the anode layer are very well aligned.

According to a preferred embodiment of the present invention, it is preferable that the material of the reinforcing layer (2) is a material which is stable at the electrode drying temperature during the coating of the positive electrode slurry. A material having a coefficient of thermal expansion similar to that of the current collector 1 may be used, and a material that does not react with the solvent used in the positive electrode slurry may be used. Further, when the anode is pressed, a flexible material having mechanical behavior similar to the shrinkage ratio of the anode layer can be used. Specifically, it is at least one selected from the group consisting of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE) and polyimide (PI) But is not limited thereto.

The thickness of the reinforcing layer 2 may be thinner than the coating thickness of the positive electrode slurry, and the thickness of the reinforcing layer 2 may be similar or small after the positive electrode is formed.

According to a preferred embodiment of the present invention, the material of the mask layer 3 may be a material which does not react with the solvent used in the positive electrode slurry. Specifically, it is preferable to use at least one selected from the group consisting of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE) and polyimide (PI) A polymer membrane or one or more metal films selected from the group consisting of aluminum (Al), nickel (Ni), and stainless steel (SUS).

According to a preferred embodiment of the present invention, when the reinforcing layer 2 and the mask layer 3 are adhered onto the current collector 1, heat can be applied between the current collector 1 and the reinforcing layer 2 The first adhesive layer may further include a second adhesive layer between the reinforcing layer 2 and the mask layer 3.

Specifically, when the positive electrode slurry is coated, the first adhesive layer may be made of a material stable to the electrode drying temperature, and preferably, a stable material may be used for the positive electrode slurry solvent. Preferably, one or more thermoplastic adhesives selected from the group consisting of polyimide, polystyrene and polyvinyl chloride which are fused by heat can be used. The first adhesive layer serves to bond the positive electrode slurry to the current collector 1 and the reinforcing layer 2 so that the positive electrode slurry is not penetrated. The thermoplastic adhesive may be coated on the reinforcing layer 2 to a thickness of 1 to 10 탆.

The second adhesive layer serves to adhere the positive electrode slurry between the reinforcing layer 2 and the mask layer 3 so that the positive electrode layer 4 is not penetrated. It is good. Preferably, a silicone system having pressure sensitive adhesive (PSA) characteristics is used.

According to a preferred embodiment of the present invention, the positive electrode layer 4 may be formed by coating the positive electrode slurry on the through hole with a surface of the current collector 1. In the above step, the cathode slurry may be cast directly on the through-hole of the current collector 1 and continuously coated by a roll-to-roll continuous process to form the anode layer 4.

The positive electrode slurry can be prepared by mixing an active material, a conductive material, a solid electrolyte and a binder in an organic solvent. The organic solvent is not particularly limited as long as it dissolves the binder and is not reactive with the other cathode slurry material.

Specifically, as the active material, for example, _{LiCoO 2, LiNi 1/3 Co} 1/3 Mn 1/3 O 2, LiMnO 2, LiVO 2, LiCrO 2, Li 2 NiMn 3 O 8, LiFePO 4, LiCoPO 4 , and LiNiO ₂ may be used.

Further, the positive electrode slurry may contain a conductive material to improve the electronic conductivity in the electrode. As the conductive material, for example, at least one selected from the group consisting of Ketjen black, acetylene black, carbon fiber and graphene can be used.

In addition, the positive electrode slurry may contain a solid electrolyte to improve the ion conductivity in the electrode. As the solid electrolyte, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, or a polymer electrolyte may be used. Specifically, the oxide-based solid electrolyte may be at least one selected from the group consisting of LiPON, Lithium phosphorous oxynitride, garnet, perovskite and NASICON (Na-super ionic conductor) A solid electrolyte may be used.

The garnet includes Li _{7 - y} La _{3 - x} A _x Zr _{2 - y} M _y O _l2 A is one kind selected from the group consisting of Y, Nd, Sm and Gd, and M is Nb or Ta. The perovskite system is a Li _{0 .5-3 x} La _{0 .5 + x} TiO ₃ structure and the NASICON (Na-super ionic conductor) system is Li _{1 + x} Al _x Ti _{2- x} (PO ₄ ) ₃ may be used to (LATP), and _{Li 1 + x Al x Ge 2} -x (PO 4) 3 (LAGP) structure, Other _{Li 1 + xy Al x Ti 2} -x Si y P 3-y O _12, the structure .

The sulfide-based solid electrolyte may include a variety of materials including an Argyrodite structure composed of Li ₂ SP ₂ S ₅ , Thio-LISICON and Li-PS, and an inorganic material composed of elements of Li-MPS (M = Si, Ge, Sn) Structure and components are known, and it is not particularly limited as long as it is a solid electrolyte containing sulfur (S).

The polymer solid electrolyte is composed of a polymer and a lithium salt. As the polymer, a form including or modified with PEO (poly ethylene oxide) is generally used. Examples of the lithium salt include lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroantimonate (LiSbF ₆ ), lithium hexafluoroacetate (LiAsF ₆ ), lithium difluoromethane sulfoxide (LiC ₄ F ₉ SO ₃ ), lithium perchlorate (LiClO ₄ ), lithium aluminate (LiAlO ₂ ), lithium tetrachloroaluminate (LiAlCl ₄ ), lithium chloride (LiCl), lithium iodide reyito borate _{(LiB (C 2 O 4)} 2), and lithium trifluoro methane sulfonyl imide _{(LiN (C x F 2x +1} SO 2) (CyF 2y +1 SO 2), where x and y are natural ), Or a combination of two or more species selected from the group consisting of

In addition, the positive electrode slurry may contain a binder to improve the binding force in the electrode. As the binder, for example, a rubber such as NBR (Nitrile butadiene rubber) or SBR (Styrene butadiene rubber), a polymer including acetonitrile, or poly vinylidene fluoride (PVDF) may be used. An ion conductive polymer such as PEO (Ethyllene oxide) containing a lithium salt may also be used.

According to a preferred embodiment of the present invention, it is preferable to remove the mask layer 3 to remove the active material layer formed outside the through hole after the anode layer 4 is formed, It can be removed by the desorption method.

According to a preferred embodiment of the present invention, the positive electrode is manufactured by forming the positive electrode layer (4) on the current collector (1) by forming the positive electrode for the whole solid battery by punching the current collector (1) It is preferable that the reinforcing layer (2) surrounds the periphery of the reinforcing layer (4).

According to another aspect of the present invention, there is provided a method of manufacturing a bipolar electrode, comprising: forming a cathode layer by coating an anode slurry on a rear surface of a collector 1 of a cathode for a front solid battery; The bipolar electrode can be manufactured by coating a solid electrolyte slurry on the cathode layer to form a solid electrolyte layer.

In addition, the method for manufacturing a pre-solid battery of the present invention includes the steps of: preparing a pre-solid electrolyte battery anode; Preparing the bipolar electrode; And an anode coated with a solid electrolyte and a cathode coated with a solid electrolyte are respectively provided at both ends and two or more bipolar electrodes are formed between the anode layer 4 of one bipolar electrode and the solid electrolyte layer of another bipolar electrode, And laminating the entire solid electrolyte.

According to a preferred embodiment of the present invention, the negative electrode layer necessarily contains at least the negative electrode active material and may contain at least one of a conductive material, a solid electrolyte and a binder, if necessary. As the negative electrode active material, for example, a carbon material such as artificial graphite, natural graphite, soft carbon, and hard carbon, or a metal active material such as Al, Sn, Si, Mg, In, Li or an alloy containing the same may be used.

In the step of forming the negative electrode layer, when Li is used as a negative electrode, a lithium foil having a thickness of 10 to 1000 mu m may be attached to the current collector 1 and used. In addition, when the negative electrode active material is used, the positive electrode layer 4 may be formed in the same manner as described above.

According to a preferred embodiment of the present invention, the solid electrolyte layer is applied on the cathode layer or the anode layer 4, and is preferably continuously applied on the cathode layer. The solid electrolyte layer is preferably formed by preparing and applying a solid electrolyte slurry, followed by drying. The solid electrolytic layer can also be formed by applying a solid electrolyte slurry to a separate film, drying it, and then pressing it together with the electrode to transfer the solid electrolyte to the electrode layer.

As the solid electrolyte slurry, an inorganic electrolyte such as an oxide-based solid electrolyte or a sulfide-based solid electrolyte may be used, or a polymer electrolyte may be used as a solid electrolyte. As the solid electrolyte used in the present invention, the above-mentioned materials may be used. Such a solid electrolyte is characterized by improving the ion conductivity in the electrode.

Therefore, in the continuous production method of a positive electrode for a full-solid battery of the present invention, a reinforcing layer including through-holes having the same size as the anode area is first formed on the current collector as compared with the existing process, and then the positive electrode slurry is coated on the through- And the anode and the anode are laminated together to form a positive electrode. Thus, the process is easy, and the alignment of the reinforcing layer and the anode layer is very excellent, thereby preventing short-circuiting of the battery due to the difference in area between the electrodes.

Also, by making the entire solid battery using the same, the interface between the anode layer and the solid electrolyte layer can be densely formed to prevent cracking of the solid electrolyte layer and to prevent a short circuit in the battery.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

[Preparation of materials]

The collector 1 was made of nickel foil.

The stiffener and the mask are made of a structure in which a plurality of through holes each having a diameter of 14 cm are patterned, and a reinforcing material and a mask in the form of a film are prepared. Here, polyethylene naphthalate (PEN) was used as the material of the reinforcing material and the mask, respectively. A polyimide thermoplastic adhesive was used as the first adhesive and a silicone pressure sensitive adhesive was used as the second adhesive.

The cathode slurry was prepared by mixing NCM622 active material, SuperC conductive material, NBR binder, and LiPSCl electrolyte in a xylene organic solvent, and then preparing a cathode slurry prepared by a conventional method.

≪ Preparation of positive electrode for all solid battery &

The mask layer 3, the second adhesive layer, the reinforcing layer 2 and the first adhesive layer were attached in order to produce an integral film. At this time, the second adhesive layer is coated on the mask layer 3, and is attached to the reinforcing layer 2 like a kind of post mouth, and is physically separated from the reinforcing layer 2. The first adhesive layer is coated on the reinforcing layer (2). Then, the film was simultaneously punched with a 14 cm diameter punching machine, and the first adhesive layer of the through-hole-opened film was placed on the current collector 1. Then, the film including the mask layer and the reinforcing layer was bonded by thermal welding at a temperature of 140 캜.

Next, the positive electrode slurry was coated on the through hole formed on one surface of the current collector 1 by a doctor blade casting method, and the mask layer 3 (including the second adhesive layer) formed on the reinforcing layer was removed by a physical tearing method.

And then dried at 110 DEG C for 24 hours to form an anode layer (4). Then, the reinforcing layer region in which the anode layer 4 was not formed was made to have a diameter of 15 cm, and a cathode was prepared by using a rubbing machine to prepare a cathode for all solid-state batteries.

1 is a schematic view showing a method of manufacturing a positive electrode for a full solid battery according to the first embodiment. As can be seen from FIG. 1, it can be seen from photographs that the reinforcing layer 2 including a plurality of through holes on the current collector 1 and the mask layer 3 are sequentially attached. Then, the cathode slurry is coated on the plurality of through holes to form the anode layer 4, and then the mask layer 3 is removed. 1 shows a series of processes for manufacturing a positive electrode having a structure in which the reinforcing layer 2 surrounds the positive electrode layer 4 by pressing the current collector 1 as shown in FIG.

Comparative Example 1

As the reinforcing layer 2 and the mask layer 3, the same PEN material as that in Example 1 was used as described below. A positive electrode for an all solid-state battery was prepared in the same manner as in Example 1, except that the order of adhering the reinforcing layer 2 and the mask layer 3 was changed.

Specifically, a mask having a structure in which a plurality of through holes each having a diameter of 14 cm was patterned was attached to one surface of a current collector 1 made of nickel foil to form a mask layer 3. The mask layer 3 and the reinforcing layer were made of the same PEN material as in Example 1. [

Then, a positive electrode slurry was coated on the through holes of the current collector 1 to form an anode layer 4, and then the mask layer 3 was removed. Then, a portion where the anode layer 4 was not formed was punched out on the current collector 1. Then, a reinforcing layer was attached on the current collector 1 so as to surround the periphery of the anode layer 4, and then pressed to produce a positive electrode for a full solid battery having a reinforcing layer 2 formed thereon.

FIG. 2 is a process diagram showing a method of manufacturing a positive electrode for a full-solid battery of Comparative Example 1. FIG. As shown in FIG. 2, first, a mask having a plurality of through holes formed on a current collector 1 is attached, and then a cathode slurry is coated on the through holes to form a cathode layer 4. Next, after the mask layer 3 is removed, an electrode is punched out as shown in FIG. 2, and a reinforcing layer 2 is formed so as to surround the periphery of the anode layer 4.

Experimental Example  One: All solids  Battery SEM  Measure

All the solid batteries were prepared in the usual manner by using the positive electrode for positive electrode prepared in Example 1 and Comparative Example 1, respectively.

≪ Preparation of all solid batteries &

Specifically, the negative electrode slurry was prepared by mixing graphite, an acrylate binder, and LiPSCl electrolyte in a solvent of xylene. The solid electrolyte slurry was prepared by mixing NBR binder and LiPSCl electrolyte in a xylene solvent.

The negative electrode current collector was coated with a negative electrode slurry by a doctor blade coating method and dried at 110 ° C to form a negative electrode layer. Then, a solid electrolyte slurry was coated on the PEN film and dried, and then the solid electrolyte layer was pressed against the negative electrode active material layer and then the PEN film was removed to form a solid electrolyte layer on the negative electrode active material. Next, the positive electrode for all the solid batteries prepared in Example 1 and Comparative Example 1 was brought into contact with the solid electrolyte layer and pressurized at 4 tons to prepare all the solid batteries. After pressurization, the solid electrolyte of Example 1 and Comparative Example 1 had a thickness of 26 mu m.

SEM measurement was carried out to confirm the cross section of each pre-solid battery thus manufactured. The results are shown in Figs.

FIG. 3 is a photograph of the boundary between the positive electrode and the solid electrolyte membrane taken from the top in the all-solid-state cell manufactured using the positive electrode prepared in Example 1 and Comparative Example 1. FIG. In FIG. 3, the collector and the reinforcing layer were separated in order to check the cracks of the all-solid-state cells manufactured in Example 1 and Comparative Example 1, and the boundary between the anode and the solid electrolyte membrane was photographed from the top.

In the case of applying the positive electrode prepared in Comparative Example 1, stress unevenness occurred at the boundary of the positive electrode / solid electrolyte contacting the positive electrode and the solid electrolyte layer at the time of pressing the cell, and cracks frequently occurred.

On the other hand, in the case of applying the positive electrode prepared in Example 1, it was confirmed that the solid electrolyte membrane is stably present even when the cell is pressurized because a well-aligned reinforcing layer exists at the rim of the anode area.

FIG. 4 is a SEM photograph showing a cross-section of a pre-solid battery manufactured using the anode prepared in Example 1. FIG. As shown in FIG. 4, it was confirmed that the solid electrolyte layer had a thickness of 30 μm or less. In this case, it was confirmed that the battery was charged / discharged stably.

On the other hand, in the case of the all-solid-state battery prepared in Comparative Example 1, when the thickness of the solid electrolyte became thinner than 50 탆, the cell resistance dropped to zero and an internal short-circuit occurred.

This makes it possible to align the reinforcing layer 2 and the anode layer 4 with each other by forming the anode layer 4 after first introducing the reinforcing layer 2 and the mask layer 3 onto the current collector 1 It was confirmed that cracking of the solid electrolyte layer at the boundary portion where the positive electrode layer 4 and the solid electrolyte layer abutted against each other and the occurrence of a short circuit within the battery could be prevented.

Experimental Example  2: All solids  The volume energy density of the battery and Charging and discharging  evaluation

All the solid batteries were produced in the same manner as in Experimental Example 1 using the positive electrodes prepared in Example 1 and Comparative Example 1 except that the solid electrolyte layers were formed to have different thicknesses as shown in Table 1 below.

Each of the prepared solid electrolytic capacitors was subjected to charge / discharge evaluation, and the volume energy density according to the change in the solid electrolyte thickness was shown in Table 1 and FIG. 5, respectively. Charging and discharging evaluation conditions were an applied current of 40 ㎂ and a voltage range (V) of 2.5 to 4.2 (CC-CV).

division Anodic loading (mg / cm ² ) Cathode loading (mg / cm ² ) Solid electrolyte thickness
(탆) Bulk energy density
(kWh / l) Example 1 10.4 5.7 26 121 Example 2 10.2 5.7 33 118 Example 3 10.2 5.7 75 103 Comparative Example 1 10.4 5.7 26 Paragraph (not evaluated) Comparative Example 2 10.2 5.7 42 Paragraph (not evaluated) Comparative Example 3 10.2 5.7 75 103

According to the results of Table 1, it can be seen that as the thickness of the solid electrolyte is decreased, the volume energy density is improved. In the case of Examples 1 to 3, the reinforcing layer and the anode layer are aligned well, It was confirmed that short-circuiting of the battery does not occur as in Comparative Examples 2 and 3 even when the thickness of the battery is thinner than 50 占 퐉.

Particularly, in the case of the all solid battery manufactured by applying the anode of Example 1, the battery was operated stably even when the thickness of the solid electrolyte was 26 μm, and the volume energy density was improved to 121 kWh / l due to the reduction in thickness. The thickness of the solid electrolyte of 26 ㎛ was similar to the thickness of the separator in the battery using the conventional liquid electrolyte, and it was found that the energy density of the unit cell, which was a problem of the conventional solid electrolyte, can be remarkably increased.

On the other hand, in the case of the all solid batteries manufactured by applying the positive electrodes of Comparative Examples 2 and 3, when the solid electrolyte thickness was less than 42 탆, the battery resistance dropped to 0, and the charge / discharge evaluation could not be performed due to the short circuit of the battery.

FIG. 5 is a graph showing the charging / discharging of all solid-state cells manufactured using the positive electrode according to Example 1 of the present invention. As shown in FIG. 5, the alignment between the reinforcing layer and the anode layer was very good, and the interface between the anode layer and the solid electrolyte layer was densely formed, thereby confirming that the charge and discharge could be stably performed.

1: Home
2: reinforced layer
3: Mask layer
4: anode layer

Claims (10)

Attaching a mask layer and a reinforcing layer including a plurality of through holes on one surface of the current collector;
Coating a positive electrode slurry on the through hole with one surface of the current collector to form a positive electrode layer;
Removing the mask layer; And
Obtaining a positive electrode having a structure in which a positive electrode layer is formed on the current collector by sputtering the current collector and the reinforcing layer surrounds the positive electrode layer;
Wherein the positive electrode comprises a positive electrode and a negative electrode.
The method according to claim 1,
Wherein the plurality of through holes are spaced apart at a predetermined distance from each other.
The method according to claim 1,
Wherein the reinforcing layer is thermally fused and adhered onto the current collector.
The method according to claim 1,
The material of the reinforcing layer may be one selected from the group consisting of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and polyimide Or more of the total weight of the positive electrode.
The method according to claim 1,
The material of the mask layer is selected from the group consisting of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and polyimide Wherein the metal film is at least one kind of polymer film or at least one metal film selected from the group consisting of aluminum (Al), nickel (Ni) and stainless steel (SUS).
The method according to claim 1,
Wherein the positive electrode further comprises a first adhesive layer between the current collector and the reinforcing layer.
The method according to claim 6,
Wherein the material of the first adhesive layer is at least one thermoplastic adhesive selected from the group consisting of polyimide, polystyrene, and polyvinyl chloride.
The method according to claim 1,
And a second adhesive layer between the reinforcing layer and the mask layer.
9. The method of claim 8,
Wherein the material of the second adhesive layer is silicon-based.
The method according to claim 1,
Wherein the positive electrode slurry includes an active material, a conductive material, a solid electrolyte, and a binder.

Images