KR101446677B1 - All-soid litium secondary battery and method for fabracating the same - Google Patents

Abstract

The present invention provides a pre-solid lithium secondary battery capable of improving the capacity of a thin film battery by using a powdery crystalline cathode active material in place of the anode produced through a deposition process. One embodiment of the pre-solid lithium secondary battery includes a first current collector, a crystalline electrode active material in the form of a powder, a first electrode disposed on the first current collector, A solid electrolyte on the electrode, and a second electrode disposed on the solid electrolyte.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state lithium secondary battery,

The present invention relates to a pre-solid lithium secondary battery and a method of manufacturing the same.

Unlike a primary battery, which can not be charged, a secondary battery is a battery capable of charging and discharging, and is widely used in high-tech electronic devices such as mobile phones, notebook computers, and camcorders. In particular, the lithium secondary battery has a working voltage of 3.6 V, which is three times higher than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for electronic equipment, and is rapidly growing in terms of high energy density per unit weight.

The lithium ion secondary battery includes an electrode assembly, a case accommodating the electrode assembly, and a cap assembly coupled to the case. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator interposed therebetween. The positive electrode plate and the negative electrode plate are manufactured by coating the current collector with the electrode active material, respectively. However, the conventional lithium ion secondary battery uses an electrolyte in liquid or polymer form, and the lithium ion battery expands due to repeated charge / discharge reactions, and has a risk of exploding.

A problem to be solved by the present invention is to provide a pre-solid lithium secondary battery capable of improving the capacity of a thin film battery by using a crystalline cathode active material in powder form instead of the anode produced through a deposition process.

Another object of the present invention is to provide a method for manufacturing the pre-solid lithium secondary battery.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a pre-solid lithium secondary battery comprising a first current collector, a first electrode including a crystalline active material in the form of a powder and disposed on the first current collector, A solid electrolyte on the first electrode, and a second electrode disposed on the solid electrolyte.

In order to solve the above-described problems, a method for manufacturing a full-solid lithium secondary battery according to the present invention comprises forming a first electrode including a crystalline active material in the form of a powder on a first current collector and forming a solid electrolyte, And forming a second current collector on the first electrode sequentially.

Other specific details of the invention are included in the detailed description and drawings.

Since the pre-solid lithium secondary battery according to an embodiment of the present invention uses a crystalline powdery active material, the thickness of the cathode active material can be thicker than that of a thin film battery by using a deposition process, .

In the method for manufacturing a pre-solid lithium secondary battery according to an embodiment of the present invention, a high-temperature heat treatment process can be omitted in manufacturing a positive electrode, thereby providing diversity in substrate selection of a pre-solid lithium secondary battery.

1 is a cross-sectional view illustrating a pre-solid lithium secondary battery according to an embodiment of the present invention.
2 is a cross-sectional view illustrating a pre-solid lithium secondary battery according to another embodiment of the present invention.
3 is a cross-sectional view illustrating a pre-solid lithium secondary battery according to another embodiment of the present invention.
4 is a flowchart illustrating a method for manufacturing a pre-solid lithium secondary battery according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Although the first, second, etc. are used to describe various elements, components and / or sections, it is needless to say that these elements, components and / or sections are not limited by these terms. These terms are only used to distinguish one element, element or section from another element, element or section. Therefore, it goes without saying that the first element, the first element or the first section mentioned below may be the second element, the second element or the second section within the technical spirit of the present invention.

It is to be understood that when an element or layer is referred to as being "on" or " on "of another element or layer, All included. On the other hand, when a device is referred to as "directly on" or "directly above ", it does not intervene another device or layer in the middle.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figure, an element described as " below or beneath "of another element may be placed" above "another element. Thus, the exemplary term "below" can include both downward and upward directions. The elements can also be oriented in different directions, in which case spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

Hereinafter, a pre-solid lithium secondary battery according to an embodiment of the present invention will be described with reference to FIG.

1 is a cross-sectional view illustrating a pre-solid lithium secondary battery according to an embodiment of the present invention.

1, the pre-solid lithium secondary battery 10 includes a first current collector 100, a first electrode 200, a solid electrolyte layer 300, a second electrode 400, a second current collector (500) and a packaging resin (600). The first electrode 200, the solid electrolyte layer 300, the second electrode 400, and the second current collector 500 may be sequentially stacked on the first current collector 100. The solid electrolyte membrane 300 is disposed between the first electrode 200 and the second electrode 400 and is in contact with the first electrode 200, the second electrode 400, and the packaging resin 600. In the description according to the embodiment of the present invention, the solid electrolyte membrane 300 is shown as not contacting with the first current collector 100 and the second current collector 500, but is not limited thereto.

Specifically, the first current collector 100 may be, for example, a positive current collector. The first current collector 100 may be, for example, a metal foil such as an alloy made of Pt, Au, Al, Ti, or a combination thereof, or carbon paper, but is not limited thereto. In the embodiments of the present invention, the first current collector 100 is described as Al foil. In the pre-solid lithium secondary battery according to an embodiment of the present invention, the first current collector 100 may not only transfer electrons generated by the oxidation-reduction reaction, but may also serve as a substrate. For example, the first current collector 100 may be a cathode current collector including the function of a substrate.

Referring to FIG. 1, the first electrode 200 is disposed on the first current collector 100. The first electrode 200 includes a hollow 210s formed between the crystalline active materials 210. The first electrode 200 may be, for example, a powdery crystalline material 210, specifically a powdery crystalline cathode material. However, the present invention is not limited thereto. If the first current collector 100 is, for example, a cathode current collector, the crystalline active material 210 included in the first electrode may be, for example, a negative active material Of course.

The first electrode 200 may further include a binder and a conductive material 220. At least some of the binder and conductive material 220 may be disposed, for example, in the hollows 210s included within the first electrode 200. [ The reason why at least a part of the binder and the conductive material 220 can be disposed in the hollows 210s in the first electrode 200 will be described with reference to FIG. 4 for explaining a method of forming the first electrode 200. FIG. The thickness of the first electrode 200 may be, for example, from 5 mu m to 1000 mu m, preferably from 10 mu m to 50 mu m, but is not limited thereto. The thickness of the first electrode 200 and the size of the crystalline active material 210 may be the same, but are not limited thereto. That is, since the crystalline active material 210 can be formed on the first current collector 100, a plurality of layers can be formed. The capacity of the pre-solid lithium secondary battery 10 can be increased by using the thick first electrode 200 including the crystalline active material 210.

For example, the crystalline active material 210, which may be a cathode active material, may be, for example, LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ LiMnO ₂ , LiNi _x Co _y Mn _z O ₂ y≤1,0≤z≤1, x + y + z = 1), LiFePO 4, xLi 2 MnO 3 and _{(1-x) LiMnO 2 (} 0 <x <1), Li 2 FeSiO 4, Li 2 FePO ₄ F, and combinations thereof. The crystalline active material 210 may have a powder form, and thus may include a hollow 210s between the crystalline active materials.

The binder may help the crystalline active material 210, the conductive material, and the first current collector 100 to bond to each other. The conductive material can improve the conductivity of the crystalline active material 210. The binder may be, for example, a binder such as polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro May include ethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluorine rubber and various copolymers thereof. The conductive material may also include, for example, carbon black, conductive fibers, metal powders, conductive whiskers, conductive metal oxides, conductive materials, and combinations thereof. Specifically, the carbon black may include, for example, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black and the like, and the conductive fiber includes, for example, carbon fiber or metal fiber can do. The metal powder may include, for example, carbon fluoride, aluminum, nickel powder and the like. The conductive whisker may include, for example, zinc oxide, potassium titanate and the like, and the conductive metal oxide may be titanium oxide or the like And the conductive material may include a polyphenylene derivative or the like.

Referring to FIG. 1, the solid electrolyte layer 300 is disposed on the first electrode 200 and separates the first electrode 200 and the second electrode 400 from each other. The upper surface of the solid electrolyte membrane 300 and the first electrode 200 may be entirely covered. The solid electrolyte layer 300 serves as a passage through which ions generated by the oxidation-reduction reaction in the first electrode 200 and the second electrode 400, that is, lithium ions Li ⁺ move. By using a solid electrolyte without using a liquid electrolyte or a polymer electrolyte, the risk that the entire solid lithium secondary battery 10 is exploded during operation can be reduced or eliminated. The solid electrolyte membrane 300 may be, for example, an inorganic solid electrolyte membrane or a polymer solid electrolyte membrane, and may be specifically LiPON, but is not limited thereto.

The second electrode 400 may be, for example, a cathode. The width of the second electrode 400 disposed on the solid electrolyte membrane 300 may be smaller than, for example, the width of the solid electrolyte membrane 300, but is not limited thereto. The second electrode 400 may include at least one of Li, Li ₄ Ti ₅ O ₁₂ , TiO ₂ , Si, Si alloy, Sn, Sn alloy, SiO, Si ₃ N ₄ , SnO ₂ and SnO .

The second current collector 500 may be, for example, a cathode current collector. The width of the second current collector 500 disposed on the second electrode 400 may be smaller than the width of the second electrode 400, for example. The width from the solid electrolyte membrane 300 to the second current collector 500 may be sequentially decreased, but is not limited thereto. The second current collector 500 may comprise at least one of, for example, Cu, Ni, V, Cr, Fe, Zr, Ta, Mn and combinations thereof. However, as in the case of the first current collector 100 and the first electrode 200, when the second electrode 400 is, for example, an anode, the second current collector 500 includes a positive current collector Of course.

The packaging resin 600 can fill the inside of the battery case 610. In other words, the packaging resin 600 surrounds the first current collector 100, the first electrode 200, the solid electrolyte film 300, the second electrode 400 and the second current collector 500 . The first current collector 100, the first electrode 200, the solid electrolyte membrane 300, the second electrode 400, and the second current collector 500 may be disposed in the battery case 610. As the packaging resin 600, for example, a resin having a low water absorption rate can be used.

The first terminal 700a and the second terminal 700b may be electrically connected to the first current collector 100 and the second current collector 500, respectively. The first terminal 700a and the second terminal 700b have the first terminal 700a and the second terminal 700b respectively connected to the first current collector 100 and the second current collector 500, Or may be electrically connected to an external electronic device. The first terminal 700a and the second terminal 700b may protrude from the battery case 610, for example.

Referring to FIG. 2, a full solid lithium secondary battery according to another embodiment of the present invention will be described. The present embodiment is substantially the same as the above embodiment except that it further includes a substrate below the first current collector. Therefore, the same reference numerals are used for the parts overlapping with the above embodiment, It is assumed to be abbreviated or omitted.

2 is a cross-sectional view illustrating a pre-solid lithium secondary battery according to another embodiment of the present invention.

2, the pre-solid lithium secondary battery 10 includes a substrate 100s, a first current collector 100, a first electrode 200, a solid electrolyte layer 300, a second electrode 400, A second current collector 500 and a packaging resin 600. [ The first current collector 100, the first electrode 200, the solid electrolyte film 300, the second electrode 400 and the second current collector 500 may be sequentially stacked on the substrate 100s have. The packaging resin 600 includes a substrate 100s, a first current collector 100, a first electrode 200, a solid electrolyte film 300, a second electrode 400, and a second current collector 500 It can be surrounded.

The substrate 100s may be disposed under the first current collector 100 and may be, for example, a flexible flexible substrate. The substrate 100s may be formed of, for example, polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), poly methyl methacrylate (PMMA), polycarbonate But is not limited to, flexible plastic substrates such as polycarbonate (PC), polyether sulfone (PES), and polyester. The substrate 100s may be connected to the first current collector 100 through, for example, an adhesive layer (not shown). Alternatively, the first current collector 100 may be formed on the substrate 100s by, for example, a deposition method, but the manner in which the substrate 100s and the first current collector 100 are bonded is not limited thereto Do not.

3, a full solid lithium secondary battery according to another embodiment of the present invention will be described. In the present embodiment, parts that are the same as those in the above-described embodiment are denoted by the same reference numerals, and a description thereof will be simplified or omitted.

3 is a cross-sectional view illustrating a pre-solid lithium secondary battery according to another embodiment of the present invention.

Referring to FIG. 3, the pre-solid lithium secondary battery 10 may include a separation pattern 110 for electrically separating the first current collector 100 and the second electrode 400. 1, the solid electrolyte layer 300 may be in contact with the first electrode 200, the second electrode 400, and the second current collector 500. The separation pattern 110 may comprise, for example, a rigid material. Also, the region of the separation pattern 110 in contact with the first current collector 100 and the first electrode 200 includes an insulating material.

Specifically, the second current collector 500 is disposed on the separation pattern 110. The first electrode 200 may be disposed on the first current collector 100. However, the first electrode 200 may be in contact with the side surface of the separation pattern 110, but not on the upper surface of the separation pattern 110. This is for electrically separating the second current collector 500 disposed on the upper surface of the separation pattern 110 from the first electrode 200. The height of the first electrode 200 is shown to be lower than the height of the separation pattern 110, but is not limited thereto. The solid electrolyte membrane 300 is disposed on the first electrode 200 and the second current collector 500. The solid electrolyte membrane 300 not only covers the first electrode 200 and the second current collector 500 but also spatially separates the first electrode 200 and the second current collector 500. The second electrode 400 may be disposed on the solid electrolyte layer 300 and the second current collector 500. The second electrode 400 may partially overlap the upper surface of the second current collector 500.

The first electrode 200, the solid electrolyte film 300, the second electrode 400, and the second current collector 500 may be formed of the same material as that of the first electrode 200, 1 current collector 100 in this order.

FIG. 3 shows that the second current collector 500 is formed on the separation pattern 110, but the present invention is not limited thereto. That is, the second current collector 500 and the first electrode 200 may be disposed with the separation pattern 110 therebetween. In order to electrically isolate the second current collector 500 from the first current collector 100, an insulating material must be formed between the second current collector 500 and the first current collector 100 .

1 and 4, a method for manufacturing a pre-solid lithium secondary battery according to an embodiment of the present invention will be described.

4 is a flowchart illustrating a method for manufacturing a pre-solid lithium secondary battery according to an embodiment of the present invention. 4 is a flowchart showing a method of manufacturing the pre-solid lithium secondary battery 10 of FIG.

Referring to FIGS. 1 and 4, a first current collector 100 is provided (S10). In the manufacturing method according to the embodiment of the present invention, the first current collector 100 is described as a positive current collector. The first current collector 100 may be, for example, a metal foil such as an alloy made of Pt, Au, Al, Ti, or a combination thereof, or carbon paper, but is not limited thereto. In one embodiment of the present invention, the first current collector 100 serves also as a substrate, so that the first current collector 100 can be provided alone without different kinds of substrate materials.

Referring to FIGS. 1 and 4, a first electrode 200 is formed on a first current collector 100 (S20). The first electrode 200 includes a crystalline active material 210 in the form of a powder. In one embodiment of the present invention, the crystalline active material 210 may be a cathode active material.

Specifically, first, a pre-electrode material to be used as the first electrode 200 is formed. In the method of forming the free electrode material, a binder, a conductive material 220, and a powdery crystalline active material 210 are put into a solvent to prepare a fluid slurry. The slurry having this fluidity is a pre-electrode material. The ratio of the materials included in the pre-electrode material excluding the solvent may be X, the conductive material Y, and the binder Z by mixing the crystalline active material 210, the conductive material, and the binder. The ratio X in which the crystalline active material 210 is included may be, for example, 60 to 98% by weight. The ratio Y in which the conductive material is contained may be, for example, 1 to 20% by weight. The ratio Z in which the binder is contained may be a value excluding the crystalline active material and the conductive material, that is, 100-X-Y, specifically, 1 to 39% by weight.

The solvent may be, for example, N-methyl pyrrolidone (NMP), and the solvent serves to mix the crystalline active material 210, the binder, and the conductive material 220. The crystalline active material 210 may be a powdery material. The crystalline active material 210 may be, for example, LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ LiMnO ₂ , LiNi _x Co _y Mn _Z O ₂ , LiFePO ₄ , xLi ₂ MnO ₃ (1-x) LiMO ₂ , Li ₂ FeSiO ₄ , Li ₂ FePO ₄ F, and combinations thereof. The binder may be, for example, a binder such as polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro May include ethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluorine rubber and various copolymers thereof. The conductive material may also include, for example, carbon black, conductive fibers, metal powders, conductive whiskers, conductive metal oxides, conductive materials, and combinations thereof. Specifically, the carbon black may include, for example, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black and the like, and the conductive fiber includes, for example, carbon fiber or metal fiber can do. The metal powder may include, for example, carbon fluoride, aluminum, nickel powder, etc. The conductive whisker may include, for example, zinc oxide, potassium titanate and the like, and the conductive metal oxide may be titanium oxide or the like And the conductive material may include a polyphenylene derivative or the like.

The prepared pre-electrode material is applied on the first current collector 100. Since the pre-electrode material is a fluid slurry, the pre-electrode material can be dried to fix it on the first current collector 100. Further, the interval between the crystalline active materials 210 included in the pre-electrode material is wide, and then the electrons may not move smoothly during the operation of the pre-solid lithium secondary battery. Accordingly, the interval of the crystalline active material 210 included in the pre-electrode material can be narrowed through the rolling process. In other words, the first electrode 200 is formed on the first current collector 100 by drying and rolling the pre-electrode material applied to the first current collector 100.

The first electrode 200 formed through such a process may include a hollow 210s therein. In other words, a pre-electrode material is formed using the crystalline powder 210 in the form of a powder. By rolling these free electrode materials, the space between the crystalline active materials 210 can be reduced to narrow the gap, but the hollows 210s between the crystalline active materials are not completely removed. That is, the hollow 210s is a space surrounded by the crystalline active material 210. [

1 and 4, a solid electrolyte membrane 300 is formed on the first electrode 200 (S30). A second electrode 400 is formed on the solid electrolyte layer 300 in step S40 and a second current collector 500 is formed on the second electrode 400 in step S50. That is, the solid electrolyte layer 300, the second electrode 400, and the second current collector 500 may be sequentially formed on the first electrode 200. The first current collector 100, the first electrode 200, the solid electrolyte film 300, the second electrode 400, and the second current collector 500 are formed by using the packaging resin 600, And packaging is performed (S60).

Specifically, the solid electrolyte membrane 300 may be, for example, LiPON, and may be formed by, for example, a sputtering method. The second electrode 400 may be, for example, a cathode, and may be made of, for example, Li, Li ₄ Ti ₅ O ₁₂ , TiO ₂ , Si, Si alloy, Sn, Sn alloy, SiO, Si ₃ N ₄ , SnO _2, and SnO. The second electrode 400 may be formed by, for example, sputtering or evaporation, but is not limited thereto. In the manufacturing method according to an embodiment of the present invention, the second electrode 400 may be formed of a metal rather than a metal oxide. Accordingly, a heat treatment process for crystallizing the second electrode 400 may be unnecessary. The second current collector 500 may be, for example, a cathode current collector and may include at least one of Cu, Ni, V, Cr, Fe, Zr, Ta, Mn, . The second current collector 500 may be formed by, for example, a sputtering method, but is not limited thereto.

The above-described method for manufacturing a pre-solid lithium secondary battery may not include a heat treatment process. This is because the active material contained in the first electrode 200 uses a powdery crystalline material having crystallinity already. As a result, it is possible to use a substrate which is weak in heat, which has been limited in use in conventional thin film batteries, under the first current collector 100.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: first current collector 100s: substrate
200: first electrode 210: crystalline active material
300: solid electrolyte membrane 400: second electrode
500: second current collector

Claims (10)

A first current collector;
A first electrode formed on the first current collector and made of a crystalline active material powder layer including one layer of crystalline active material powder particles and having a thickness equal to that of the crystalline active material powder particles;
A solid electrolyte membrane disposed directly on the first electrode; And
And a second electrode disposed on the solid electrolyte membrane. delete delete The method according to claim 1,
Wherein the crystalline active material powder layer comprises a binder and a conductive material. 5. The method of claim 4,
Wherein the crystalline active material powder layer includes a hollow between the crystalline particles of the active material and at least a part of the binder and the conductive material are disposed in the hollow. The method according to claim 1,
Wherein the crystalline active material powder particle is a cathode active material,
Wherein the crystalline active material powder particles are selected from the group consisting of LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ LiMnO ₂ , LiNi _x Co _y Mn _z O ₂ (0≤x≤1, 0≤y≤1, 0≤z≤1, x + y + z = 1), LiFePO ₄ , xLi ₂ MnO ₃ (1-x) LiMnO ₂ (0 <x <1), Li ₂ FeSiO ₄ , Li ₂ FePO ₄ F, Solid state lithium secondary battery. Forming a first electrode on the first current collector, the first electrode being made of a crystalline active material powder layer containing one layer of crystalline active material powder particles and having a thickness equal to that of the crystalline active material powder particles;
A solid electrolyte membrane is disposed directly on the first electrode,
And forming a second current collector and a second current collector on the solid electrolyte film in this order. 8. The method of claim 7,
The formation of the first electrode
Comprising the crystalline active material powder particles, producing a pre-electrode material having fluidity,
Applying the pre-electrode material on the first current collector,
And drying and rolling the applied pre-electrode material. 9. The method of claim 8,
The formation of the pre-electrode material
A method for producing a pre-solid lithium secondary battery, which comprises forming a slurry by putting a binder, a conductive material and the crystalline active material powder particles in a solvent. 8. The method of claim 7,
Wherein the solid electrolyte layer, the second electrode, and the second current collector are deposited by a sputtering method.

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