阅读说明：本技术 锂二次电池 (Lithium secondary battery ) 是由 严惠悧 李承栽 崔率 韩大运 于 2018-03-26 设计创作，主要内容包括：本发明涉及一种锂二次电池,该锂二次电池包括电极,该电极包括：集流体,该集流体包括其中纤维束是交叉编织的织物形式的结构,其中每个纤维束由纤维纱线组形成,每个纤维纱线包括聚合物纤维和围绕聚合物纤维的金属层；以及设置在集流体的至少一个表面上的活性物质层。(The present invention relates to a lithium secondary battery including an electrode including: a current collector comprising a structure in which fiber bundles are in the form of a cross-woven fabric, wherein each fiber bundle is formed from a set of fiber yarns, each fiber yarn comprising a polymer fiber and a metal layer surrounding the polymer fiber; and an active material layer disposed on at least one surface of the current collector.)

1. A lithium secondary battery comprising an electrode, the electrode comprising:

a current collector comprising a structure in which fiber bundles are in the form of a cross-woven fabric,

wherein each of said fiber bundles is formed from a set of fiber yarns,

the fiber yarn includes a polymer fiber and a metal layer surrounding the polymer fiber; and

an active material layer disposed on at least one surface of the current collector.

2. The lithium secondary battery according to claim 1, wherein the structure has an elongation of 5% to 45%.

3. The lithium secondary battery according to claim 1, wherein a volume ratio of the polymer fiber with respect to an entire volume of the structure is 50% to 90%.

4. The lithium secondary battery according to claim 3, wherein the volume ratio is 60% to 80%.

5. The lithium secondary battery according to claim 1, wherein the diameter of the fiber bundle is 15 to 30 μm.

6. The lithium secondary battery according to claim 1, wherein the polymer fiber is selected from the group consisting of polyethylene terephthalate, polypropylene, polyethylene, and combinations thereof.

7. The lithium secondary battery according to claim 1, wherein the thickness of the metal layer is 150nm to 1500 nm.

8. The lithium secondary battery according to claim 1, wherein the metal layer comprises nickel, cobalt, iron, or silver; and copper or aluminum.

9. The lithium secondary battery according to claim 8, wherein the metal layer includes a first metal layer surrounding the polymer fiber and a second metal layer surrounding the first metal layer,

the first metal layer comprises nickel, cobalt, iron or silver, and

the second metal layer comprises copper or aluminum.

10. The lithium secondary battery according to claim 9, wherein the metal layer further comprises a third metal layer surrounding the second metal layer,

each of the first metal layer and the third metal layer comprises nickel, cobalt, iron, or silver, and

the second metal layer comprises copper or aluminum.

11. The lithium secondary battery according to claim 10, wherein the thickness of the second metal layer is greater than the thickness of each of the first metal layer and the third metal layer.

12. The lithium secondary battery according to claim 10, wherein the thickness of the second metal layer is 100nm to 1000 nm.

13. The lithium secondary battery according to claim 10, wherein a thickness ratio of the thickness of the second metal layer to the thickness of each of the first metal layer and the third metal layer is greater than 1 and less than or equal to 6.

Technical Field

The present invention relates to a lithium secondary battery.

Background

Recently, many flexible electronic products such as flexible displays, flexible RFIDs, flexible organic solar cells, flexible transistors, flexible sensors, etc. have proliferated and become commercially available. Further, in order to operate such electronic devices while utilizing the flexible characteristics, a battery having good flexibility is inevitably required. However, some flexible batteries have been developed at the research level at present, but the cycle life characteristics or capacity of the batteries are insufficient for the actual industry. As a result of research on flexible batteries, such as flexible batteries using fabrics, flexible batteries using metal mesh screens or Carbon Nanotubes (CNTs) as current collectors, etc., is being conducted in various ways, but they have not been greatly developed in terms of battery performance.

Accordingly, efforts have been made to develop a flexible battery for a flexible secondary battery having excellent performance.

Disclosure of Invention

Technical problem

Drawings

Fig. 1 is a schematic view illustrating a structure in a current collector according to an embodiment.

Fig. 2 is a schematic view illustrating a lithium secondary battery according to an embodiment.

Fig. 3 is a graph illustrating cycle-life characteristics of a lithium secondary battery according to an embodiment.

< description of symbols >

100: lithium secondary battery

10: electrode assembly 20: battery case

13: electrode lug

1 polymer fiber 2 Metal layer containing Nickel

3: copper/aluminum containing metal layer

201: fiber bundle 101: structure of the product

301: fiber yarn

Embodiments provide a lithium secondary battery including a current collector that improves output characteristics of the battery by improving flexibility and metal strength while reducing the outermost irreversible capacity of a stacked lithium secondary battery, and expanding the interface area of an electrode and the current collector to facilitate electron transfer.

Technical scheme

An embodiment of the present invention provides a lithium secondary battery including an electrode including: a current collector comprising a structure in which fiber bundles are in the form of a cross-woven fabric, wherein each fiber bundle is formed from a set of fiber yarns comprising polymer fibers and a metal layer surrounding the polymer fibers; and an active material layer disposed on at least one surface of the current collector.

The elongation of the structure may be 5% to 45%.

The volume ratio of the polymer fibers relative to the overall volume of the structure may be 50% to 90%.

The volume ratio may be 60% to 80%.

The diameter of the fiber bundle may be 15 μm to 30 μm.

The polymer fibers may be selected from the group consisting of polyethylene terephthalate, polypropylene, polyethylene, and combinations thereof.

The thickness of the metal layer may be 150nm to 1500 nm.

The metal layer may comprise nickel, cobalt, iron or silver; and copper or aluminum.

The metal layer may include a first metal layer surrounding the polymer fiber and a second metal layer surrounding the first metal layer, the first metal layer may include nickel, cobalt, iron, or silver, and the second metal layer may include copper or aluminum.

A third metal layer surrounding the second metal layer may also be included, each of the first and third metal layers may include nickel, cobalt, iron, or silver, and the second metal layer may include copper or aluminum.

The thickness of the second metal layer may be greater than the thickness of each of the first metal layer and the third metal layer.

The thickness of the second metal layer may be 100nm to 1000 nm.

A thickness ratio of the thickness of the second metal layer to the thickness of each of the first metal layer and the third metal layer may be greater than 1 and less than or equal to 6.

Advantageous effects

By using a current collector having both improved flexibility and metal strength, the outermost irreversible capacity in the stacked lithium secondary battery can be reduced, and the interfacial area between the current collector and an active material layer applied on the current collector can be enlarged to facilitate electron transfer, thereby providing a lithium secondary battery having improved battery output characteristics.