KR101905168B1 - Bipolar All Solid-State Battery And Fabricating Method Thereof - Google Patents

Abstract

The present invention provides a bipolar pre-solid battery capable of operating a manufacturing process more efficiently and improving electrical characteristics and to a manufacturing method thereof. For example, the bipolar pre-solid battery comprises: a bipolar current collector having one surface and the other surface opposite to the one surface; a first active material coated on one surface of the bipolar current collector; a second active material formed on the other surface of the bipolar current collector; and a unit cell including a pre-solid electrolyte formed between the first active material and the second active material, and the second active material is formed by depositing lithium foil on the other surface of the bipolar current collector.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a bipolar all-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bipolar pre-solid battery capable of operating a manufacturing process more efficiently and improving electrical characteristics, and a manufacturing method thereof.

Generally, a lithium ion secondary battery has higher energy density than other secondary batteries and can operate at a high voltage. Therefore, secondary batteries which are liable to be reduced in size and weight are mainly used for information devices such as cellular phones and the like, and demand for large-sized power such as electric vehicles and hybrid vehicles is recently increasing.

Such a lithium ion secondary battery includes a positive electrode layer, a negative electrode layer, and an electrolyte layer disposed therebetween. As the electrolyte, for example, a non-aqueous liquid or a solid is used. When a liquid (hereinafter referred to as " electrolyte ") is used in the electrolyte, the electrolyte easily penetrates into the anode layer or the cathode layer. Therefore, the interface resistance between the active material contained in the positive electrode layer and the negative electrode layer (hereinafter referred to as " electrode layer ") and the electrolyte is small, and battery performance is easily improved. However, since the electrolyte is flammable, various additional complicated systems are required to secure safety. On the other hand, since the solid electrolyte (hereinafter referred to as " solid electrolyte ") is incombustible, the complicated system can be simplified. Therefore, a lithium ion secondary battery (hereinafter referred to as a "solid battery") in which a layer containing a non-combustible solid electrolyte (hereinafter referred to as a "solid electrolyte layer") is provided.

The above-described information disclosed in the background of the present invention is only for improving the understanding of the background of the present invention, and thus may include information not constituting the prior art.

The present invention provides a bipolar pre-solid battery capable of operating a manufacturing process more efficiently and improving electrical characteristics, and a method of manufacturing the same.

A bipolar pre-solid battery according to the present invention includes: a bipolar current collector having one surface and a surface opposite to the one surface; A first active material coated on one surface of the bipolar current collector; A second active material formed on the other surface of the bipolar current collector; And a whole solid electrolyte formed between the first active material and the second active material. The second active material may be formed by depositing a lithium foil on the other surface of the bipolar current collector.

Here, the bipolar current collector may be formed of stainless steel (SUS), nickel, nickel alloy, or aluminum / copper clad metal.

The area of the first active material may be larger than the area of the second active material.

In addition, the total solid electrolyte may be formed to have a larger area than that of the first active material and the second active material.

The bipolar current collector may further include an insulation film formed on the top surface of the bipolar current collector to surround the second active material when the unit cell is stacked.

Also, the insulating film may be composed of any one selected from polyimide (PI), polyethylene (PE), and polypropylene (PP).

In addition, a method of manufacturing a bipolar pre-solid battery according to the present invention includes: winding a bipolar current collector having a first active material on one surface thereof and a second active material on the other surface thereof; Winding all solid electrolytes on rolls; And supplying the bipolar current collector and the pre-solid electrolyte between the two rotating rollers and pressing them through the rollers.

Here, the second active material may be formed by depositing a lithium foil on the other surface of the bipolar current collector.

The bipolar pre-solid battery according to the present invention includes a bipolar current collector having active materials on both surfaces thereof, and a unit cell including a pre-solid electrolyte formed between the active material. When the unit cells are connected in series, The bipolar pre-solid battery structure can be easily formed.

Further, in forming the negative electrode active material, by attaching the lithium foil to the bipolar current collector, it is possible to easily and easily produce the all solid battery.

Further, a structure in which a bipolar current collector has an active material formed on a roll at the time of forming the unit cell and a pre-solid electrolyte is also wound around a roll, and these structures are pressed between the two rollers, All solid batteries can be produced.

In addition, by forming the coating area of the cathode active material larger than the coating area of the anode active material, and by forming the coating area of the entire solid electrolyte to be larger than the coating area of the active materials, the movement of lithium, which is fluid, It is possible to prevent the deterioration of the electrical characteristics caused by the above.

In addition, an insulating film is formed between the stacks of the unit cells to prevent the electrical characteristics from deteriorating due to the contact between all the solid electrolytes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a stack of a bipolar pre-solid battery according to an embodiment of the present invention; FIG.
FIG. 2 is a view showing a process of laminating all solid electrolytes of a bipolar pre-solid electrolyte according to an embodiment of the present invention.
3 is a view illustrating a stack of a bipolar pre-solid battery according to another embodiment of the present invention.
4 is a view showing a stack of a bipolar pre-solid battery according to another embodiment of the present invention.
5 is a plan view showing a film sheet used in a bipolar pre-solid battery according to another embodiment of the present invention.
6A and 6B are plan views showing front and rear bipolar current collectors in which a film sheet is laminated in a bipolar pre-solid battery according to another embodiment of the present invention.
FIG. 7 is a graph showing a performance evaluation result of a bipolar pre-solid battery according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

In the following drawings, thickness and size of each layer are exaggerated for convenience and clarity of description, and the same reference numerals denote the same elements in the drawings. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. In the present specification, the term " connected "means not only the case where the A member and the B member are directly connected but also the case where the C member is interposed between the A member and the B member and the A member and the B member are indirectly connected do.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise, " and / or "comprising, " when used in this specification, are intended to be interchangeable with the said forms, numbers, steps, operations, elements, elements and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

Although the terms first, second, etc. are used herein to describe various elements, components, regions, layers and / or portions, these members, components, regions, layers and / It is obvious that no. These terms are only used to distinguish one member, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

It is to be understood that the terms related to space such as "beneath," "below," "lower," "above, But may be utilized for an easy understanding of other elements or features. Terms related to such a space are for easy understanding of the present invention depending on various process states or use conditions of the present invention, and are not intended to limit the present invention. For example, if an element or feature of the drawing is inverted, the element or feature described as "lower" or "below" will be "upper" or "above." Thus, "lower" is a concept encompassing "upper" or "lower ".

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a stack of a bipolar pre-solid battery according to an embodiment of the present invention; FIG.

Referring to FIG. 1, a bipolar pre-solid electrolyte cell stack 10 according to an embodiment of the present invention includes a bipolar current collector 110, a first active material 120, a second active material 130, and a solid electrolyte 140 ) May be stacked. In addition, a first outline current collector 150 and a second outline current collector 160 may be formed at the outermost portion of the stack 10.

Further, in order to reduce the electrical resistance when the surface of the bipolar current collector 110, particularly the surface exposed to the outside of the unit cell, is brought into contact with neighboring unit cells, any one of platinum, silver, gold, An adhesive or paste composed of a metal may be further formed.

The first active material 120 is formed on one surface of the bipolar current collector 110. When the first active material 120 operates as a positive electrode, the first active material 120 is coated on a well-known conventional cathode active material such as nickel cobalt manganese (NCM), lithium cobalt oxide (LCO), and nickel cobalt aluminum (NCA) And perovskite, and garnet-type sulfide-based solid electrolytes such as oxide and binary sulfide, and ion conductive and binder-functional polymers such as PEO and PPO, Super P, and CNT. However, the present invention is not limited to the material of the first active material 120.

The second active material 130 is formed on one surface of the bipolar current collector 110, that is, on the other surface of the bipolar current collector 110 on which the first active material 120 is not applied. That is, the second active material 130 is formed symmetrically with respect to the first active material 120 with respect to the bipolar current collector 110.

The second active material 130 may be formed of a material such as silicon oxide (SiO ₂ ) or tin oxide (SnO ₂ ), which is a lithium ion storage material based on a graphite based material. The second active material 130 may include a first active material 120 Similarly, a composite electrode using an ion and an electron conductive material, a binder and a conductive agent may be used, or lithium metal may be used.

However, the second active material 130 may be formed by attaching a thin foil made of lithium to the other surface of the bipolar current collector 110 instead of using the graphite or graphite. That is, the second active material 130 can be easily formed by attaching a lithium foil to the bipolar current collector 110 instead of applying a separate material. Particularly, in this case, the second active material 130 has an advantage that the ion capacity can be increased as compared with conventional graphite or graphite.

The solid electrolyte 140 is prepared by mixing an ion conductive LLZO (Li _x La _y Zr _z O ₁₂ ), an ion conductive binder (for example, PEO) and a lithium salt in an organic solvent (for example, ACN) May be formed. Here, x = 6 to 9 moles, y = 2 to 4 moles, and z = 1 to 3 moles. The lithium salt may be, for example, LiClO ₄ , though it is not limited thereto. In addition, the lithium salt is _{LiCl, LiBr, LiI, LiClO 4} , LiBF 4, LiB10Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF 3 SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, chloroborane lithium, lithium lower aliphatic carboxylate and lithium tetraphenylborate, or a mixture of two or more thereof.

The first sub-current collector 150 may serve as a current collector constituting the unit cell located at the lowermost part. In this case, the second active material 130 may be formed on one surface of the first outer current collector 150. On the other hand, the active material may not be coated on the other side of the first outer collector 150. Therefore, the first sub-collector 150 does not have to be a bipolar current collector, and thus may be formed of copper or a copper alloy for efficiency.

The second sub-current collector 160 may serve as a current collector constituting the uppermost unit cell. In this case, the first active material 120 may be formed on one surface of the second outer current collector 160. On the other hand, no active material may be applied to the other surface of the second outer collector 160. Therefore, the second outer current collector 160 does not need to be a bipolar current collector, and thus may be formed of aluminum or an aluminum alloy for efficiency.

The battery stack 10 includes the bipolar current collector 110, the first active material 120, the second active material 130, and the second active material 130 between the first outer current collector 150 and the second outer current collector 160. [ And the pre-solid electrolyte 140 are repeatedly stacked, so that they can be connected in series.

Particularly, in the battery stack 10, the first solid electrolyte 120 and the second active material 130 are formed on both surfaces of the bipolar current collector 110, As shown in FIG. The cell stack 10 is stacked on the final cell stack 10 based on a unit cell in which a pre-solid electrolyte 140 is formed between the first active material 120 and the second active material 130 10).

Hereinafter, a method of manufacturing a bipolar pre-solid battery according to an embodiment of the present invention will be described in more detail.

FIG. 2 is a view showing a process of laminating all solid electrolytes of a bipolar pre-solid electrolyte according to an embodiment of the present invention.

2, a bipolar pre-solid battery according to an embodiment of the present invention has a structure in which a first active material 120 and a second active material 130 are formed on both surfaces of the bipolar current collector 110, Alternatively, the entire solid electrolyte 140 may be provided. That is, the bipolar current collector 110, the first active material 120, and the second active material 130 may be separately wound on one roll, and the entire solid electrolyte 140 may be wound on another separate roll As shown in FIG.

2, the structure of the bipolar current collector 110, the first active material 120 and the second active material 130 and the structure of the entire solid electrolyte 140 Can be supplied from the rolls while being unwound, and these structures can be squeezed with the rollers (A, B). According to this method, the structures of the bipolar current collector 110, the first active material 120 and the second active material 130 and the pre-solid electrolyte 140 are provided in advance, The basic structure of the unit cell can be easily manufactured in a large amount. Therefore, it is possible to reduce the cost and process required for manufacturing the bipolar pre-solid battery 10 according to an embodiment of the present invention.

Hereinafter, the structure of a bipolar pre-solid battery according to another embodiment of the present invention will be described.

3 is a view illustrating a stack of a bipolar pre-solid battery according to another embodiment of the present invention.

3, a battery stack 20 of a bipolar pre-solid battery according to another embodiment of the present invention includes a bipolar current collector 210, a first active material 220, a second active material 230, 240). In addition, a first sub-collector 250 and a second sub-collector 260 may be provided at the outermost portion of the cell stack 20. Here, the material of each structure can be configured in the same manner as each of the battery stacks 10 in the above-described embodiment, and will not be described separately for the sake of explanation.

The area of the bipolar current collector 210 and the first active material 220 applied to the bipolar current collector 210 may be larger than the area of the second active material 230 applied to the bipolar current collector 210 .

3, the size of the first active material 220 is larger than that of the second active material 230 in the stacked cell 20 in which the unit cells 200 are stacked, . In this case, it is possible to prevent the flowing lithium from flowing into the first active material 220 in the components of the second active material 230, particularly, the negative active material. Accordingly, the bipolar pre-solid battery according to another embodiment of the present invention has a structure capable of preventing a decrease in electrical characteristics such as a short circuit due to the movement of the active material in the structure of the stacked battery 20.

Referring to FIG. 3, the entire solid electrolyte 240 may have a larger area than other structures. This configuration can effectively prevent the active material, particularly lithium of the second active material 230, from being transferred to the first active material 220 of the unit cell located below.

Hereinafter, the structure of a bipolar pre-solid battery according to another embodiment of the present invention will be described.

4 is a view showing a stack of a bipolar pre-solid battery according to another embodiment of the present invention. 5 is a plan view showing a film sheet used in a bipolar pre-solid battery according to another embodiment of the present invention. 6A and 6B are plan views showing front and rear bipolar current collectors in which a film sheet is stacked in a bipolar pre-solid battery according to another embodiment of the present invention. Parts having the same configuration and operation as those of the previous embodiment are denoted by the same reference numerals, and differences from the preceding embodiment will be mainly described below.

4, the stacked battery 30 of a bipolar pre-solid battery according to another embodiment of the present invention includes a bipolar current collector 210, a first active material 220, a second active material 230, The first outer collector 250, and the second outer collector 260 may be provided in the same manner as the stack battery 20 of the previous embodiment. The stacked battery 30 may further include an insulating film 370 to surround the second active material 230 on the upper portion of the bipolar current collector 210 located below.

The insulating film 370 is basically made of an insulating material such as polyimide (PI), polyethylene (PE), or polypropylene (PP), and has a through hole 371 therein. Through the through holes 371, contact between the second active material 230 and the stacked pre-stacked solid electrolytes 240 in the stack structure becomes possible, thereby enabling serial connection of the unit cells.

The insulating film 370 may remain attached to the upper and lower second active materials 230 and the entire solid electrolyte 240 through a spray adhesive, though not separately shown. The spray adhesive can be formed as a material having electrochemical stability with high potential.

Due to the attachment of the insulating film 370, the contact between the entire solid electrolyte 240 in the stacked battery 30 can be fundamentally cut off, thereby preventing deterioration of electrical characteristics such as a short circuit.

Hereinafter, characteristics of the bipolar pre-solid battery according to an embodiment of the present invention will be described.

FIG. 7 is a graph showing a performance evaluation result of a bipolar pre-solid battery according to an embodiment of the present invention.

Referring to FIG. 7, in a bipolar pre-solid battery according to an embodiment of the present invention, three unit cells were stacked in series, and then a test was conducted through a prototype product finally assembled with a pouch case.

7, the open-circuit voltage OCV of the battery stack 10 after charging is about 12.3 V and the average discharge voltage is about 11.1 V. When applied to one unit cell, about 3.7 [ The discharge capacity of the prototype according to the present invention was about 105 [mAh / g] as a result of discharging at a current density of 0.05 [C] at 70 [ Was confirmed. These characteristics show almost the same level as the discharge capacity of a unit cell, and excellent reversibility can be confirmed even in a charge / discharge cycle. Therefore, it is confirmed that the entire solid battery cell / stack according to the present invention can be manufactured easily by the bipolar structure, and the quality problem such as short circuit is largely controlled.

The present invention is not limited to the above-described embodiment, but may be modified in various ways within the spirit and scope of the present invention as set forth in the following claims. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

10, 20, 30; Battery stack
110, 210; Bipolar current collector 120, 220; The first active material
130, 230; A second active material 140, 240; All solid electrolytes
150, 250; A first outer housing 160, 260; The second outer housing
370; Insulating film

Claims (8)

A bipolar current collector having one surface and the other surface opposite to the one surface;
A first active material coated on one surface of the bipolar current collector;
A second active material formed on the other surface of the bipolar current collector; And
A unit cell including a sheet-like pre-solid electrolyte formed between the first active material and the second active material,
The second active material is formed by attaching a lithium foil to the other surface of the bipolar current collector,
Wherein the area of the first active material is larger than the area of the second active material when stacking the unit cells, and the total solid electrolyte is formed larger than the area of the first active material and the second active material. The method according to claim 1,
Wherein the bipolar current collector is formed of a stainless metal (SUS), a nickel, a nickel alloy, or an aluminum / copper clad metal. delete delete The method according to claim 1,
And an insulating film formed on the upper surface of the bipolar current collector to surround the second active material when stacking the unit cells. 6. The method of claim 5,
Wherein the insulating film is made of any one selected from polyimide (PI), polyethylene (PE), and polypropylene (PP). Winding a bipolar current collector having a first active material on one surface and a second active material on the other surface;
Winding all solid electrolytes on rolls;
Supplying the bipolar current collector and the sheet-like pre-solid electrolyte between the two rotating rollers and pressing them through the rollers,
Wherein the area of the first active material is larger than the area of the second active material and the total solid electrolyte is formed larger than the area of the first active material and the second active material. 8. The method of claim 7,
Wherein the second active material is formed by attaching a lithium foil to the other surface of the bipolar current collector.

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