Art
[1]
This application claims the benefit of priority based on a 224 day year and the Korea Patent Application No. 10-2016-0021618 No. 11 dated May 28, 2016 Korea Patent Application No. 10-2016-0158987 January 2016, and of the Korea Patent Application everything described in the literature comprises a part of this specification.
[2]
The present invention relates to an electrode assembly for a lithium secondary battery, a lithium secondary battery and a battery module including the same that has an improved cathode structure.
BACKGROUND
[3]
Application of electronics, communications, computer, industrial energy-saving technology to the rapid development of camcorders, mobile phones, notebooks, PC, go electric vehicles is being expanded. As a result, light can be long, and there is ongoing development of a reliable high-performance rechargeable batteries.
[4]
The lithium secondary cell is spotlighted as a battery that meets these demands.
[5]
The lithium secondary battery is configured by being having an electrode assembly is wound or laminated structure comprising a separator interposed between the positive and negative electrodes with these, an electrode assembly is built into the battery case, the electrolytic solution is injected therein. The lithium secondary battery is a lithium ion to produce electrical energy by oxidation and reduction reaction when the intercalation / deintercalation at the positive and negative electrodes.
[6]
A negative electrode of a lithium secondary battery is a lithium sheet is laminated on a copper foil generally forms house. When the cathode is in contact with a liquid electrolyte is an intensive corrosion reaction takes place in an electrolytic solution is penetrated between the lithium sheet / a negative electrode current collector surface. The corrosion due to the reaction stability of the lithium is reduced, a problem arises, such as a cathode to form a layer structure of the crystalline or amorphous, or due to the exothermic reaction, a localized temperature rise.
[7]
As proposed for solving the problem in the Republic of Korea Patent Publication No. 2006-0125852 No. lithium nitrate (LiNO on the surface of the electrode 3 proposes a technique of forming a protective layer containing an additive such as a). This method led to more increase the weight of the cell and thus increase in cost of the process according to the result of a separate protection layer is formed on the electrode but is possible to solve the problem presented above.
[8]
In a method of adding a non-functional layer, such as the protective layer using an insulating tape to the existing structure it has been proposed. Typically the negative electrode collector is larger production than the lithium sheet to the corrosion reaction is lithium sheet / a negative electrode current collector and at the interface between the full especially occurs seriously consider yirwojim, lithium sheet and does not contact the anode current collector outer peripheral surface of an insulating tape a method of fixing or forming the insulating layer has been proposed. However, the formation of the insulating tape / insulating layer also could never ignore the cost aspect according to a further process.
[9]
On the other hand, in a lithium secondary battery, a battery, which is the recent interest in soybean, lithium using a sulfur-based material as a positive electrode active material has a sulfur battery. Lithium-sulfur cell is the theoretical discharge capacity of 1672mAh / g-sulfur, the theoretical energy density as 2,600Wh / kg, theoretical energy density of the other battery systems that are currently studies (Ni-MH cells: 450Wh / kg, Li-FeS battery: 480Wh / kg, Li-MnO 2 has been noted as a very high due to high cell density in the energy characteristics compared to 800Wh / kg): cell: 1,000Wh / kg, Na-S cells.
[10]
However, the actual lithium Achieving this theoretical value during use of the sulfur battery has a limitation in several ways.
[11]
A lithium-sulfur battery of the major problems is due to the inherently unique shuttle mechanism by polysulfide dissolution leading to the inert reaction for the reduction of sulfur oxide (shuttle mechanism). In other words, when the water-soluble intermediate consisting of a sulfur chain having a lithium distally polysulfide (polysulfide) is frequently occur without utilizing and spread between the positive and negative shuttle developer consumed in the cell, a current flows continuously in the cell this is caused, or the discharge product therefrom deposit on the surface of the electrode, the dissolved polysulfide can be recycled to the sulfur (sulfur) not as a result causes a decrease in the discharge capacity. This phenomenon is called self-discharge (self-discharge), which has attracted attention as an important challenge to be addressed as one of the major causes lowering the efficiency of the battery.
[12]
The lithium-sulfur battery of self and various attempts are underway to improve the discharge.
[13]
Eon Sung Shin et sulfur (or poly reduce the wetting characteristics of the anode by applying a high concentration of salt (common ion effect) or the polymer electrolyte as part of a method of changing the composition of the electrolyte and through the common ion effect (Common ion effect) reducing the solubility of the sulfide) has disclosed that they can inhibit the self-discharge. This method, however, a new problem was caused by the use of high levels of electrolyte that are reactive with sulfur cathode active material decreases.
[14]
Also, Nasim Azimi the like was to suppress the self-discharge by reducing the solubility of the sulfur (or polysulfide) by applying a fluorine-containing ether and an ionic liquid as an electrolyte composition. Thus changing the composition of the electrolyte lithium-but secured either the self-discharge suppressing / inhibiting effect of sulfur battery level, there is a disadvantage that must be applied to the specific electrolyte component.
[15]
Thus, in a battery using a lithium anode lithium sheet / a negative electrode collector corrosion reaction at the interface with, but sulfur self-in battery using sulfur for the positive electrode minimizing the discharge reaction, competitive in terms of the process is of a relatively simplified and cost the development of methods that can be urgently secured.
[16]
[17]
[Prior art document]
[18]
[Patent Document]
[19]
Republic of Korea Patent Publication No. 2006-0125852 call, (12.06.2006), an electrolyte for lithium-sulfur batteries (Electrolytes for Lithium Sulfur Cells)
[20]
Republic of Korea Patent Publication No. 2005-0096926 call, (06.10.2005), the current collector sheet and electrochemical device
[21]
Non-patent literature;
[22]
Eon Sung Shin et al., Polysulfide dissolution control: the common ion effect, Chem. Commun., 2013,49, 2004-2006
[23]
Nasim Azimi, et al, Fluorinated Electrolytes for Li-S Battery: Suppressing the Self-Discharge with an Electrolyte Containing Fluoroether Solvent, J. Electrochem. Soc., 162 A64 (2015)
Detailed Description of the Invention
SUMMARY
[24]
The present applicant is blocking the contact of the lithium metal / anode current collector surface and the electrolyte in view of the corrosion reaction and the idea that he can be fundamentally prevented by the discharge time for the electrode, forming a functional layer on the electrode, or the composition of the electrolyte changes were only changes the form of the negative electrode collector without. As a result, the charging and discharging characteristics of the lithium secondary battery is improved, to confirm the production of a lithium secondary battery is possible in a cost-effective way and completed the present invention.
[25]
Accordingly, it is an object of the present invention is to provide a lithium secondary battery, the electrode assembly newly change the structure of the negative electrode collector.
[26]
Another object of the present invention is to provide a lithium secondary battery comprising the lithium secondary battery, the electrode assembly.
[27]
Further, another object of the present invention to provide a battery module and a battery pack provided with the lithium secondary battery, the electrode assembly.
Problem solving means
[28]
To achieve the above object, the present invention provides a plurality of the negative electrode mixed material laminated on both sides of the negative electrode current collector is a negative electrode; A plurality of positive electrode The positive electrode material mixture is laminated on both sides of the positive electrode collector; And the electrode assembly consisting of a separator interposed between the cathode and the anode,
[29]
The negative electrode material mixture is a lithium metal sheet and provides a lithium secondary battery, an electrode assembly, characterized in that the negative electrode current collector having a larger area than the total area.
[30]
At this time, the whole of the negative electrode current collector is characterized by having an area greater than 0 to less than 100% compared to the area of ​​the lithium negative electrode material mixture.
[31]
Further, the present invention provides a lithium secondary battery comprising the lithium secondary battery, the electrode assembly.
[32]
At this time, the lithium secondary battery is a lithium-sulfur battery is characterized in that.
[33]
The present invention also provides a battery module and a battery pack which the lithium is provided with whether battery.
Effects of the Invention
[34]
Electrode assembly for a lithium secondary battery proposed in the present invention has the advantage that no corrosion reactions take place, the use of sulfur as an anode in accordance with the self-discharge will not occur improved charging and discharging characteristics of the battery.
[35]
In particular, the ease of the application associated with the manufacturing steps of the advantages by simply changing only the shape of the negative electrode collector without the addition of a new functional layer or the composition economical, conventional lithium secondary battery, in the electrode assembly.
Brief Description of the Drawings
[36]
1 is a cross-sectional view of an electrode assembly according to one embodiment of the present invention.
[37]
Figure 2 is a schematic view showing a cathode structure in accordance with one embodiment of the invention.
[38]
Figure 3 is a schematic view showing the size change of the negative electrode collector.
[39]
Figure 4 is a schematic diagram for explaining a lithium metal sheet and the anode current between the total length and width according to the present invention.
[40]
5 is a schematic view showing a joined state of the lithium metal sheet and the negative electrode current collector in accordance with various embodiments of the present invention.
[41]
Figure 6 is a schematic diagram for explaining the spacing of the negative electrode collector to the lithium metal sheet according to the present invention.
[42]
Figure 7 is a lithium produced in Comparative Example 1 and Example 1 of the present invention is a comparison of the charge-discharge cycle characteristics of the sulfur battery graph.
Best Mode for Carrying Out the Invention
[43]
With reference to the drawings the present invention will be described in more detail.
[44]
1 is a cross-sectional view of the electrode assembly 100 according to one embodiment of the present invention. 1, the electrode assembly 100 is provided with a separator 30 interposed between the cathode 10 and anode 20, and mixtures thereof.
[45]
Cathode 10, and are stacked, that this structure is stacked a plurality pieces anode mix (13a, 13b) on both sides of the negative electrode current collector 11.
[46]
Further, the anode 20 is a is laminated, such a structure is stacked a plurality pieces cathode mix (23a, 23b) on both sides of a cathode current collector (21).
[47]
At this time, the electrode separator 30 between the cathode 10 and the anode 20 of the assembly 100 is interposed, inside the electrode assembly 100 is filled with electrolyte (not shown).
[48]
[49]
In the electrode assembly 100 also has the structure of 1, the present invention is the cathode 10, in particular anode current collector in the form of body 11, sikidoe Among them, changing the area of ​​the negative electrode material mixture (13a, 13b) area of ​​the contrast predetermined range It is fundamentally blocked by the corrosion reaction and the self-discharge time for the electrode with the change.
[50]
The cathode current collector 11 to present according to the present invention is not particularly limited, if the material and shape of the well-known bar can be any one.
[51]
Specifically, the anode current collector 11 so long as it has suitable conductivity without causing chemical changes in the fabricated battery is not particularly limited, for example, copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel It can be a cadmium alloy and the like to be used - the surface carbon, nickel, titanium, a is one of the treatment surface, such as aluminum.
[52]
In addition, the anode current collector 11 may be used in various forms, such as having a minute unevenness on a surface / non-formed films, sheets, foils, nets, porous structures, foams and non-woven fabrics. To the most preferable as the negative electrode current collector 11 uses a copper foil.
[53]
The negative electrode material mixture (13a, 13b) presented in this invention may be a lithium metal or a lithium alloy. A lithium alloy containing an element is lithium and the alloy making available, at which time the elements Si, Sn, C, Pt, Ir, Ni, Cu, Ti, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Sb, Pb, in, Zn, Ba, Ra, Ge, Al, may be Sn or an alloy thereof.
[54]
In addition, the negative electrode material mixture (13a, 13b) may be a lithium metal sheet.
[55]
Area change of the negative electrode material mixture (13a, 13b) against the anode current collector 11 may be described, as shown in Figs.
[56]
2 and 3 are schematic diagrams showing the structure of a negative electrode 10 in accordance with one embodiment of the invention. 2, the cathode 10 is interposed between the anode current collector 11, tab 15 is provided for supplying current to one side is disposed a negative electrode material mixture (13a, 13b) on both sides.

Claims
[Claim 1]
A plurality of negative electrode with a negative electrode mixed material laminated on both sides of the negative electrode current collector; A plurality of positive electrode The positive electrode material mixture is laminated on both sides of the positive electrode collector; And a lithium secondary battery having an electrode assembly, characterized in that the negative electrode and the electrode assembly consisting of a separator interposed between the positive electrode, the negative electrode material mixture is a lithium metal sheet, a larger area than the area of ​​the entirety of the negative electrode current collector.
[Claim 2]
The method of claim 1, wherein the anode current collector is an electrode assembly for a lithium secondary battery, characterized in that having an area of ​​less than 100% excess compared to the area 0 of the lithium negative electrode material mixture.
[Claim 3]
The method of claim 1, wherein the negative electrode material mixture on both sides is laminated on the electrode assembly for a lithium secondary battery characterized in that in contact with each other at a predetermined area.
[Claim 4]
The method of claim 1, wherein the anode current collector is an electrode assembly for a lithium secondary battery, characterized in that the spaced apart inward from the outer circumferential surface of the negative electrode material mixture.
[Claim 5]
The method of claim 1, wherein the lithium secondary battery, the electrode assembly characterized in that arranged to match the center point of the anode current collector and the center of the negative electrode material mixture.
[Claim 6]
The method of claim 1, wherein the lithium secondary battery, an electrode assembly, which satisfy the above negative electrode current collector and to have a horizontal width of the negative electrode material mixture Equation 1. [Equation 1] 0