KR101637896B1 - Electrode Assembly with Liquid Materials Receiver for Insulation - Google Patents

Abstract

The present invention relates to an electrode assembly including two or more unit cells, and more particularly, the unit cell has a structure in which one or more positive electrodes and one or more negative electrodes are stacked with a separator interposed therebetween, The cells are stacked in the height direction with respect to the paper surface, all the unit cells are wound by one sheet type separation film, and in the wound state, at the portion of the sheet type separation film corresponding to at least one of the uppermost and lowermost ends of the electrode assembly And a secondary battery including the electrode assembly is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrode assembly having a liquid-

The present invention relates to an electrode assembly having an insulating liquid material accommodating portion formed by a lamination and folding method.

The secondary battery is classified into a cylindrical battery and a prismatic battery in which the electrode assembly is housed in a cylindrical or rectangular metal can according to the shape of the battery case, and a pouch-shaped battery in which the electrode assembly is housed in a pouch-shaped case of an aluminum laminate sheet .

Also, the secondary battery is classified according to how the electrode assembly having the anode / separator / cathode structure is formed. Typically, the long battery-shaped anodes and cathodes are jelly- A stacked (stacked) electrode assembly in which a plurality of positive electrodes and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator interposed therebetween, a stacked (stacked) electrode assembly in which a predetermined unit of positive and negative electrodes are stacked, A stack / folding type electrode assembly having a structure in which a bicell or a full cell stacked in a state is wound is exemplified.

Recently, due to the high capacity of the battery, much attention has been paid to the large-sized case and the processing of a thin material. Accordingly, a structure in which a stacked or stacked / folded electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet The pouch-shaped battery of the present invention has been gradually increased in usage due to low manufacturing cost, small weight, and easy shape deformation.

However, when a sharp object having electrical conductivity such as a nail penetrates the battery, that is, when the needle-like conductor having a sharp end passes through the battery, the electrochemical energy inside the battery is converted into thermal energy, The positive electrode or the negative electrode material undergoes a chemical reaction by the heat generated from the battery, which may lead to safety problems such as ignition and explosion of the battery. Such a safety problem may also occur when the battery is pressed against a heavy object, subjected to strong impact, or exposed to a high temperature. Such safety problems are becoming more serious as the capacity of lithium secondary batteries is increased and the energy density is increased.

Therefore, it can be manufactured in a small size and light weight while providing a high output large capacity, and it is possible to secure safety against one of the most important problems, especially, external physical impact, and to prevent short- There is a high need for a battery having such a structure that it is more safe to prevent such a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

Specifically, it is an object of the present invention to provide a method for manufacturing a battery, in which when a needle-like conductor penetrates a battery, electrochemical energy inside the battery is converted into thermal energy, and rapid heat generation occurs, and a positive or negative electrode material chemically reacts with the accompanying heat, The present invention provides an electrode assembly having a structure for securing safety by attaching an insulating liquid material storage member to a pouch-shaped battery cell, and a secondary battery including the electrode assembly.

According to an aspect of the present invention, there is provided an electrode assembly comprising:

An electrode assembly comprising two or more unit cells,

The unit cell has a structure in which one or more positive electrodes and one or more negative electrodes are stacked with a separator interposed therebetween,

Wherein the unit cells are stacked in a height direction with respect to the paper surface, all the unit cells are folded by one sheet-

And the insulating liquid-substance-containing portion is provided at a portion of the sheet-like separation film corresponding to at least one of the uppermost and lowermost ends of the electrode assembly in the folded state.

That is, the electrode assembly according to the present invention has a structure in which a sequentially laminated structure of a cathode / separator / anode / separator or a cathode / separator / cathode / separator is a basic unit (radical cell) And a liquid-phase-material-accommodating portion for insulation is provided at the uppermost and lowermost ends of the electrode assembly when stacking / folding the unit cells.

Generally, a unit cell, which is a unit cell, may be a bicycle having the same type of electrodes located on both sides. Bicell has a basic laminated structure of anode (cathode) / separator / cathode (anode) / separator / anode (cathode). That is, a bi-cell is a cell in which the same electrode is located on both sides of a cell, such as a unit structure of a cathode / separator / cathode / separator / anode and a unit structure of a cathode / separator / anode / separator / cathode. In this specification, a cell having a cathode / separator / cathode / separator / anode structure is referred to as a C-type bi-cell, and a cell having a cathode / separator / anode / separator / cathode structure is referred to as an A-type bi-cell. That is, a cell in which an anode is located on both sides is called a C-type bi-cell, and a cell in which a cathode is located on both sides is called an A-type bi-cell. If the electrodes on both sides of the cell have the same structure, the number of the positive electrode, the negative electrode, and the separator constituting the bi-cell are not particularly limited.

In a specific example, when the needle-like conductor penetrates the battery, or when the needle-shaped member, which is a non-conductive sharp end, penetrates the battery, the insulating property that absorbs the liquid substance that prevents sudden heat generation, ignition, The liquid material storage portion may be located at the uppermost end and the lowermost end of the electrode assembly, respectively. Therefore, if the needle-shaped conductor passes through the case of the insulating liquid material receiving portion, the insulating liquid material may be sealed in the insulating liquid material case so as to flow out of the insulating liquid material case and into the electrode assembly.

Accordingly, the insulating liquid material that has entered the electrode assembly reacts with the electrodes and the electrolyte in the electrode assembly, thereby preventing internal shorts, heat generation, ignition, and explosion.

The insulating liquid material may be at least one selected from the group consisting of, for example, a silicone oil, a polymer having a branched hydrocarbon chain, and a perfluorinated material, but is not limited thereto. Specifically, the insulating liquid material stored in the insulating liquid material-containing portion may be a thermosetting resin or a photocurable resin. For example, the insulating liquid material stored in the insulating liquid material-containing portion may be silicone oil.

For example, when the needle-shaped conductor penetrates through the case of the insulating liquid material storage portion, the silicone oil flows out of the insulating liquid material case and enters the electrode assembly to react with the electrode or electrolyte in the battery cell to prevent ignition and explosion.

In addition, the insulating liquid material may be a perfluorinated solution. The perfluorinated material is a material having excellent thermal conductivity and insulation. When the needle-like member penetrates the inside of the pack case, the perfluorinated material flows out from the insulating liquid material receiving portion.

Meanwhile, the case of the insulating liquid-phase-containing portion is formed so that the needle-like member ruptures by the needle-like member when the needle-shaped member passes through the battery case containing the electrode assembly and enters the battery, It can be formed of a material having appropriate rigidity. The case of the liquid material accommodating portion may be formed of various materials, for example, synthetic resin, silicone, etc., but is not limited thereto.

Further, the insulating liquid material receiving portion may have a shape corresponding to the unit cell in plan view. Therefore, if a part of the unit cell is curved, the insulating liquid material accommodating portion can be deformed corresponding to the curved shape.

In one specific example, the insulative liquid material receiving portion of the shape corresponding to the unit cell may be 80% to 120% of the unit cell size in plan view. The thickness of the liquid material receiving portion for insulation may be 50% to 200% of the thickness of the unit cell.

Specifically, it is difficult to protect the unit cell from the needle-shaped conductor if the size or thickness of the insulating liquid material receiving portion is too small or thin as compared with the unit cell size. If the size or thickness of the insulating liquid material receiving portion is too large If it is large or thick, the volume increases as a whole compared to the capacity of the battery, which is not preferable.

The present invention also provides a battery cell having a structure in which the electrode assembly is embedded in a cell case.

The cell case is made of a laminate sheet including a resin layer and a metal layer, and may be a case of various structures such as a rectangular or cylindrical can, a pouch-shaped case of a laminate sheet, but is not limited thereto.

The battery cell may be a secondary battery, and the secondary battery may be a lithium secondary battery.

However, the lithium secondary battery contains various combustible materials, and there is a danger of overheating or explosion due to overcharging, overcurrent, other physical external impact, etc., and thus has a serious safety drawback. Accordingly, a lithium secondary battery is provided with a positive temperature coefficient (PTC) element, a protection circuit module (PCM), or the like as a safety element capable of effectively controlling an abnormal state such as overcharging or overcurrent, Lt; / RTI >

The present invention can also be a battery pack including a battery cell as a unit cell. The battery pack may have a structure in which various safety members or external members are coupled to the battery cells.

The present invention may also be a device including a battery pack. The device may be selected from a cellular phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, have.

The structure and manufacturing method of such a device are well known in the art, so a detailed description thereof will be omitted herein.

INDUSTRIAL APPLICABILITY As described above, the electrode assembly according to the present invention can secure safety against one of the most important problems, in particular, against external physical impact.

Further, the present invention provides an effect of more effectively solving safety problems such as ignition and explosion of cells when the needle-shaped conductors penetrate unit cells.

1 is a perspective view of a conventional pouch-shaped battery cell;
2 is a schematic diagram showing an A-type bi-cell and a C-type bi-cell structure applied to a folding structure of a conventional electrode assembly;
3 is a schematic diagram of a cross-sectional structure in which bi-cells are stacked and folded according to one embodiment of the present invention;
4 is a schematic view of a cross-sectional structure of an A-type bi-cell and a C-type bi-cell structure of an electrode assembly according to another embodiment of the present invention;
5 is a schematic view of a cross-sectional structure of an A-type bi-cell and a C-type bi-cell structure of an electrode assembly according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

Fig. 1 schematically shows a perspective view of a conventional pouch-type battery cell.

1, the pouch-type secondary battery 10 includes an electrode assembly 20 including an anode, a cathode, and a separator disposed between the anode and the cathode, 21, and 22 are electrically connected to each other to be exposed to the outside.

The battery case 11 is composed of a case body 15 including a concave shaped storage portion 13 on which the electrode assembly 20 can be seated and a cover 12 integrally connected to the body 15 have.

The battery case 11 is made of a laminated sheet and is composed of an outermost resin layer forming an outermost layer, a barrier metal layer for preventing penetration of a material, and an inner resin layer for sealing.

In the stacked electrode assembly 20, a plurality of positive electrode tabs 21 and a plurality of negative electrode tabs 22 are fused to each other and are coupled together to the electrode leads 25 and 26. In addition, when the upper end of the case body 15 and the upper end of the cover 12 are thermally fused by a heat sealer (not shown), a short circuit is prevented from occurring between the heat sealer and the electrode leads 25, 26, Insulating films 28 and 29 are attached to the upper and lower surfaces of the electrode leads 25 and 26 in order to secure the sealing properties of the battery case 11 and the battery case 25 and 26.

FIG. 2 is a schematic view showing an A-type bi-cell 30 and a C-type bi-cell 40 structure applied to a folding structure of a conventional electrode assembly.

2 (a) is an A-type bi-cell 30 of a conventional general structure, in which anodes 31 and 35, separators 32 and 34, and a cathode 33 are sequentially stacked, And the lowest layer is a cathode. FIG. 2 (b) is a C-type bi-cell 40 of a conventional general structure in which cathodes 43 and 45, separators 42 and 44 and a cathode 41 are sequentially stacked, And a bi-cell having a structure in which the lowest layer is an anode.

FIG. 3 is a schematic view of a cross-sectional structure in which bi-cells are stacked and folded according to an embodiment of the present invention.

Referring to FIG. 3, a folded state of the electrode assembly 100 according to the present invention is schematically shown. In the stacked state, the unit cells 101, 102, 103, 104, and 105 are stacked and folded at the center of the electrode assembly 100, And a second insulating liquid material receiving portion 120 is disposed under the lowermost bipolar cell. At the end of folding, an insulating tape 160 is added to stably maintain the stacking and folding structure.

Fig. 4 is a schematic view showing a structure of an electrode assembly before folding according to the present invention.

Referring to Fig. 4, unit cells 201, 202, 203, 204, 205, 206, and 207 are arranged at the winding start portion of the electrode assembly sheet before folding. The unit cells 201, 202, 203, 204, 205, 206, and 207 are bi-cells having the same type of electrodes located on both sides. The unit cells 201 are arranged in the winding start portion and the unit cells 202, 203, 204, 205, 206, and 207 are arranged in the folding direction by a width corresponding to one unit cell 201 , And an A-type bi-cell and a C-type bi-cell are arranged in a pair. The first insulating liquid material storage portion 220 and the second insulating liquid material storage portion 240 are arranged in the winding end portion. Insulating materials are contained in the insulating liquid-phase-material accommodating portions 220 and 240.

That is, in a state after the A type bi-cell and the C type bi-cell structure are stacked and folded, a separator is interposed between the anode and the cathode, and the insulating liquid material receiving portion 220 is stacked on the uppermost layer And the insulating liquid material receiving portion 240 is laminated on the lowermost layer.

FIG. 5 is a schematic view showing another structure of the electrode assembly before folding according to the present invention.

Referring to FIG. 5, unit cells 301, 302, 303, 304, 305, 306, and 307 are arranged in the winding start portion on the electrode assembly sheet before folding. The unit cells 302, 303, 304, 305, 306, and 307 are spaced apart from each other by a width corresponding to one unit cell 301 in the folding direction and the A type bi- (302, 303, 304, 305, 306, 307) are arranged in pairs. The insulative liquid-phase-material accommodating portion 320 is arranged at the winding end portion. The insulating liquid-phase-material accommodating portion 320 is also made of a material that folds the electrode assembly one or more times, and has a width that folds the electrode assembly after folding one or more times.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (20)

An electrode assembly comprising two or more unit cells,
The unit cell has a structure in which one or more positive electrodes and one or more negative electrodes are stacked with a separator interposed therebetween,
The unit cells are stacked in the height direction with respect to the paper surface, all the unit cells are wound by one sheet-like separation film,
The insulating liquid material storage portion is provided at a portion of the sheet-like separation film corresponding to at least one of the uppermost and lowermost ends of the electrode assembly in the wound state,
Wherein the insulating liquid material receiving portion is located between the sheet type separating film and the unit cells at the uppermost and lowermost ends of the electrode assembly and the liquid material for insulation is sealed inside the case,
Wherein the insulating liquid material is a thermosetting resin or a photocurable resin. The electrode assembly according to claim 1, wherein the unit cells are bi-cells having the same type of electrodes located on both sides. The electrode assembly according to claim 2, wherein the bi-cell has a basic lamination structure of a cathode (anode) / separator / cathode (anode) / separator / anode (cathode). delete delete delete The electrode assembly according to claim 1, wherein the insulating liquid material is at least one selected from the group consisting of a silicone oil, a polymer having a branched hydrocarbon chain, and a perfluorinated material. The electrode assembly according to claim 1, wherein the case is a pouch-shaped sheet case. The electrode assembly according to claim 1, wherein the case is a box-shaped box case. The electrode assembly of claim 1, wherein the case is made of a rigid material. 11. The electrode assembly of claim 10, wherein the rigid material is synthetic resin or silicone. The electrode assembly according to claim 1, wherein the insulating liquid material receiving portion has a shape corresponding to a unit cell in plan view. The electrode assembly according to claim 1, wherein the insulating liquid material receiving portion has a size ranging from 80% to 120% of the size of the unit cell in plan view. The electrode assembly according to claim 1, wherein the thickness of the insulating liquid material receiving portion is 50% to 200% of the thickness of the unit cell. A battery cell characterized in that the electrode assembly according to claim 1 is embedded in a cell case. 16. The battery cell according to claim 15, wherein the cell case comprises a laminate sheet including a resin layer and a metal layer. The battery cell according to claim 15, wherein the battery cell is a secondary battery. The battery cell according to claim 17, wherein the secondary battery is a lithium secondary battery. A battery pack comprising the battery cell according to claim 15 as a unit cell. A device comprising a battery pack according to claim 19.

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