KR20180111324A - Electrode assembly - Google Patents

Abstract

The present invention relates to an electrode assembly. According to the present invention, the electrode assembly comprises: an electrode and a separator alternately stacked and assembled; and a vaporizing agent applied to the electrode and generating gas upon overcharging. The electrode includes an electrode collector and an electrode active material coated on the electrode collector. The vaporizing agent is applied to a non-coated portion to which the electrode active material is not applied in the electrode collector.

Description

ELECTRODE ASSEMBLY

The present invention relates to an electrode assembly.

Unlike primary batteries, rechargeable secondary batteries can be recharged, and they are being researched and developed recently due to their small size and high capacity. As technology development and demand for mobile devices increase, the demand for secondary batteries as energy sources is rapidly increasing.

The secondary battery is classified into a coin type battery, a cylindrical type battery, a square type battery, and a pouch type battery depending on the shape of the battery case. An electrode assembly mounted in a battery case of a secondary battery is a chargeable and dischargeable power generation device having a stacked structure of an electrode and a separation membrane.

The electrode assembly includes a jelly-roll type in which a separator is interposed between a positive electrode and a negative electrode coated with an active material, and a stacked type in which a plurality of positive electrodes and negative electrodes are sequentially stacked with a separator interposed therebetween And a stack / folding type in which stacked unit cells are wound with a long length separating film. The double jelly roll type electrode assembly is widely used because it has an advantage of being easy to manufacture and having high energy density per weight.

Korean Patent Publication No. 10-2016-0010121

One aspect of the present invention is to provide an electrode assembly in which cell performance and capacity are prevented from deteriorating, and carbon dioxide (CO 2) gas is smoothly discharged to enhance cell stability.

Another aspect of the present invention is to provide an electrode assembly capable of preventing a separator or an adjacent electrode from being damaged through a stepped portion.

An electrode assembly according to an embodiment of the present invention includes electrodes alternately stacked and collected, a separator, and a vaporizing agent applied to the electrode and generating a gas upon overcharging, wherein the electrode comprises an electrode collector, And the vaporizing agent may be applied to the non-coated portion of the electrode current collector to which the electrode active material is not applied.

The electrode assembly according to the present invention can prevent deterioration of the performance and capacity of the battery and smoothly discharge the carbon dioxide (CO2) gas during overcharging by applying lithium carbonate, which is a vaporizing agent, to the electrode non-coated portion. Accordingly, the current blocking member is short-circuited by the carbon dioxide discharged during the overcharge to cut off the current, thereby increasing the battery stability.

In addition, the electrode assembly according to the present invention may be formed by applying lithium carbonate to cover the electrode tab to prevent the adjacent separator from being damaged by the step of the positive electrode tab, thereby preventing shorting of the electrode .

In the electrode assembly according to the present invention, lithium carbonate is coated on the non-coated portion of the electrode current collector so as not to generate a step between the electrode current collector and the electrode active material stacked on the electrode current collector, It is possible to prevent the adjacent separation membrane from being damaged by short-circuiting of the electrode.

In addition, the electrode assembly according to the present invention may be coated with the lithium carbonate on the non-coated portion located on the center side of the wound electrode to receive less influence of the tension.

1 is an exploded perspective view of a secondary battery to which an electrode assembly according to a first embodiment of the present invention is applied.
2 is a cross-sectional view illustrating an electrode assembly according to a first embodiment of the present invention.
3 is a plan view showing an exemplary electrode according to the first embodiment of the present invention.
4 is a view showing a state in which the electrode assembly according to the first embodiment of the present invention is unfolded before being wound.
FIG. 5 is a diagram showing an example of the area A in FIG.
FIG. 6 is a diagram showing another example of the area A in FIG.
7 is a view showing a state in which the electrode assembly according to the second embodiment of the present invention is unfolded before being wound.
8 is a view showing an example of a state in which the electrode assembly according to the third embodiment of the present invention is unfolded before being wound.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Furthermore, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In the following description of the present invention, a detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

1 is an exploded perspective view of a secondary battery to which an electrode assembly according to a first embodiment of the present invention is applied.

1, the electrode assembly 100 according to the first embodiment of the present invention includes electrodes 130 and separators 140 and 150 alternately stacked, and a vaporizer 190 is disposed on the non- .

FIG. 2 is a cross-sectional view illustrating an electrode assembly according to a first embodiment of the present invention, FIG. 3 is a plan view illustrating electrodes according to a first embodiment of the present invention, FIG. 4 is a cross- FIG. 2 is a conceptual view showing a state in which the electrode assembly according to the present invention is unfolded.

Hereinafter, an electrode assembly according to a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6. FIG.

Referring to FIGS. 1 and 2, the electrode assembly 100 is a chargeable and dischargeable power generation element. The electrode 130 and the separators 140 and 150 are assembled and alternately stacked. Here, the electrode assembly 100 may have a wound form.

The electrode assembly 100 may be applied to the secondary battery 10 in such a manner that the electrode assembly 100 is inserted into the battery case 11 and covered with the cap assembly 12 to be sealed. The cap assembly 12 includes a top cap 12a on which a discharge port is formed and a safety vent 12b having a rupture portion ruptured when the internal pressure of the secondary battery 10 rises, And a current blocking member 12c that ruptures when the inner pressure of the secondary battery 10 rises and blocks the current.

Referring to FIGS. 1 and 4, the electrode assembly 100 may further include an electrode tab 180 electrically connected to the electrode 130 according to the first embodiment of the present invention. Here, the electrode tab 180 may include a positive electrode tab 170 and a negative electrode tab 160. The secondary battery 10 may include a positive electrode lead 13 electrically connected to the positive electrode tab 170 and a negative electrode lead 14 electrically connected to the negative electrode tab 160.

Referring to FIGS. 2 and 4, the electrode 130 may include an electrode current collector 131 and an electrode active material 132 coated with the electrode current collector 131. Here, the electrode active material 132 may be applied to the electrode current collector 131 such that the electrode current collector 131 has uncoated portions at both ends thereof. At this time, the electrode active material 132 may be applied to the center of the electrode current collector 131, for example, so as to form a uniform width portion at both ends of the electrode current collector 131.

In addition, the electrode 130 may include a cathode sheet 120 and a cathode sheet 110. The separators 140 and 150 separate and electrically isolate the cathode sheet 120 and the cathode sheet 110 from each other.

The positive electrode sheet 120 and the negative electrode sheet 110 may be rolled together with the separators 140 and 150 to be formed into a roll shape. Here, the electrode assembly 100 may be wound in a circular or oval shape. For example, the electrode assembly 100 may be formed as a jelly roll type.

On the other hand, the center portion of the wound electrode assembly 100 may be formed with a predetermined space H. Here, the space portion H of the electrode assembly 100 may be formed to penetrate the center portion of the electrode assembly 100 in a direction parallel to the center axis on which the electrode assembly 100 is wound.

3 and 4, the anode sheet 120 may be formed of a sheet including an aluminum (Al) material. The positive electrode sheet 120 may include a positive electrode collector 121 and a positive electrode active material 122 coated on the positive electrode collector 121.

The anode current collector 121 may be made of, for example, a foil made of aluminum (Al).

The cathode active material 122 may be composed of, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound or mixture thereof containing at least one of the foregoing.

In addition, the cathode active material 122 may be made of a Hi Ni-based cathode material. Here, the Hi Ni-based cathode material may include any one or more of LiNiMnCoO-based, LiNiCoAl-based, and LiMiMnCoAl-based materials. At this time, the content of nickel (Ni) may be 0.5 mol to 0.95 mol.

On the other hand, the positive electrode tab 170 may be provided on the non-coated portion A1 where the positive electrode active material 122 is not applied. At this time, the positive electrode tab 170 may be provided on the non-coated portion A1 positioned on one of the non-coated portions A1 and A2 positioned at both ends of the positive electrode current collector 121. [

Referring to FIG. 4, the negative electrode sheet 110 may be formed of a sheet containing copper (Cu) or nickel (Ni) material. The negative electrode sheet 110 may include a negative electrode collector 111 and a negative electrode active material 112 applied to the negative electrode collector 111.

The anode current collector 111 may be made of, for example, a foil made of copper (Cu) or nickel (Ni).

The anode active material 112 may be made of a material including artificial graphite.

In addition, the negative electrode active material 112 may be made of lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound or an alloy thereof.

Meanwhile, the negative electrode tab 160 may be provided on the non-coated portion where the negative electrode active material 112 is not applied.

Referring to FIGS. 2 and 4, the separators 140 and 150 are made of an insulating material and alternately stacked with the cathode sheet 120 and the cathode sheet 110. Here, the separators 140 and 150 may be positioned between the positive electrode sheet 120 and the negative electrode sheet 110, and on the outer surfaces of the positive electrode sheet 120 and the negative electrode sheet 110.

The separation membranes 140 and 150 may be formed of, for example, a polyolefin-based resin film such as microporous polyethylene, polypropylene or the like.

The vaporizing agent 190 may be applied to the solid portion of the electrode 130. That is, the igniter 190, which generates gas upon overcharging, may be applied to the non-coated portion where the electrode active material 132 is not coated on the electrode current collector 131. At this time, the vaporizing agent 190 may be made of, for example, lithium carbonate (Li 2 CO 3, Li carbonate). As a result, the coating amount of the electrode active material 132 can be maximized, and battery performance and capacity can be increased. That is, if lithium carbonate is mixed with the electrode active material 132 and coated on the portion to which the electrode active material 132 is applied so that lithium carbonate, which is a material for preventing overcharging, is included in the battery, The performance and capacity of the battery will be further reduced.

Accordingly, the present invention can remarkably increase the performance and capacity of the battery even more when compared with the case where the lithium carbonate is mixed with the electrode active material 132 and coated on the area where the electrode active material 132 is applied.

Then, for example, the vaporizing agent 190 may be applied to the non-coated portion of the cathode current collector 121.

When the voltage of the secondary battery is over 4.5 V, the lithium carbonate (Li 2 CO 3) is electrolyzed to generate carbon dioxide (CO 2). At this time, the current interruption device (CID) It can be short-circuited to cut off the current. As a result, the current is cut off during overcharging, and explosion and ignition of the secondary battery 10 due to overcharging can be prevented. Here, lithium carbonate (Li2CO3) can be decomposed into lithium oxide (LiO) and carbon dioxide (CO2) at a voltage of 4,5 V or higher (see Fig. 1)

Further, the vaporizing agent 190 may be applied to the non-coated portion located on the side of the center of the wound electrode 130. That is, the vaporizing agent 190 may be applied to the non-coated portion side of the electrode 130 positioned at the winding center portion when the non-coated portion formed on both sides of the wound electrode 130 is wound. At this time, the vaporizing agent 190 may be applied to the entire surface of the non-coated portion located on the center side of the electrode 130. Here, the vaporizing agent 190 may be applied to the entire surface of the non-coated portion of the positive electrode sheet 120 positioned on the center side of the electrode 130, for example.

The vaporizing agent 190 is applied to the non-coated portion positioned on the side of the central portion when the electrode 130 is wound so that the influence of the tension that may occur on the jelly roll structure in which the electrode 130 and the separating films 140 and 150 are wound Can be minimized. That is, this portion can also solve the problem of tension that may occur in the jelly structure, as compared with the case where lithium carbonate is mixed with the electrode active material 132 and applied to the region where the electrode active material 132 is applied.

The carbon dioxide gas vaporized in the vaporizing agent 190 through the space portion H formed in the center of the wound electrode assembly 100 is easily discharged to the outside of the electrode assembly 100 through the space portion H .

In addition, the vaporizing agent 190 may be applied to the non-coated portion to cover the electrode tabs 180. At this time, the electrode tab 180 is attached to one side of the non-coated portion of the electrode current collector 131, and the vaporizing agent 190 covers one side of the electrode tab 180 positioned on the electrode current collector 131 Can be applied. Accordingly, the vaporizing agent 190 can prevent breakage of the adjacent separation membranes 140 and 150 due to the step of the electrode tabs 180. As a result, the edges of the electrode tabs 180 can prevent the electrodes 130 from being short-circuited due to breakage of the separating films 140 and 150 that isolate the electrodes 130. Here, for example, the vaporizing agent 190 may be applied to the non-coated portion of the cathode current collector 121 so as to cover the cathode tab 170.

The vaporizing agent 190 may be applied to the non-coated portion of the electrode current collector 131 to a portion adjacent to the electrode active material 132 to prevent a step from being formed at the end of the electrode active material 132. That is, the vaporizing agent 190 may be applied up to the boundary between the electrode active material 132 and the non-coated portion.

FIG. 5 is a view showing an example of the area A in FIG. 4, and FIG. 6 is a view showing another example of the area A in FIG.

5, the vaporizing agent 190 may be applied to the electrode collector 131 such that the height b1 of the electrode active material 132 and the height a1 of the vaporizing agent 190 are the same, . At this time, for example, the uppermost surface from the electrode current collector 131 of the vaporizing agent 190 may be located on the same line as the uppermost surface from the electrode current collector 131 of the electrode active material 132.

6, the vaporizing agent 190 'may be formed in such a manner that the height a2 of the vaporizing agent 190' is lower than the height b2 of the electrode active material 132 ). ≪ / RTI > At this time, for example, the uppermost surface from the electrode current collector 131 of the vaporizing agent 190 'may be positioned lower than the uppermost surface from the electrode current collector 131 of the electrode active material 132. Here, the vaporizing agent 190 'may be formed to have a predetermined height lower than that of the electrode active material 132 to form a predetermined space. That is, the vaporized carbon dioxide may be easily separated from the upper surface of the vaporizing agent 190 'and the adjacent separation membranes 140 and 150 by a predetermined distance. For example, the height difference c between the vaporizing agent 190 'and the electrode active material 132 may be 10 to 30% of the height b2 of the electrode active material 132.

7 is a view showing a state in which the electrode assembly according to the second embodiment of the present invention is unfolded before being wound.

7, the electrode assembly 200 according to the second embodiment of the present invention is different from the electrode assembly 100 according to the first embodiment in that electrode active material 132, and the vaporizing agent 290 is applied to the uncoated portions of the electrode current collector 131 on both sides.

More specifically, in the electrode assembly 200 according to the second embodiment of the present invention, the electrode 230 may include an electrode current collector 231 and an electrode active material 232 coated on both surfaces of the electrode current collector 231 have. The positive electrode sheet 220 may include a positive electrode collector 121 and positive electrode active materials 122 and 123 formed on both surfaces of the positive electrode collector 121. The negative electrode sheet 210 may include the negative electrode collector 111 and the negative electrode active materials 112 and 113 coated on both sides of the negative collector 111.

In addition, in the electrode assembly 200 according to the second embodiment of the present invention, the vaporizing agent 290 may be applied to the non-coated portions formed on both sides of the electrode 230. Here, the vaporizing agent 290 may be applied to, for example, a non-coated portion positioned on the center side of the wound electrode 230. That is, the vaporizing agent 290 can be applied to the non-coated portion side of the electrode 230 positioned at the winding center portion when the uncoated portion formed on both sides of the wound electrode 230 is wound.

8 is a view showing an example of a state in which the electrode assembly according to the third embodiment of the present invention is unfolded before being wound.

8, the electrode assembly 300 according to the third embodiment of the present invention is different from the electrode assembly 100 according to the first embodiment described above and the electrode assembly 200 according to the second embodiment , The vaporizing agent 390 is applied to the uncoated portion of the positive electrode sheet 320 and the uncoated portion of the negative electrode sheet 310. [

More specifically, in the electrode assembly 300 according to the third embodiment of the present invention, the vaporizing agent 390 may be applied to the non-coated portion of the positive electrode sheet 320 and the non-coated portion of the negative electrode sheet 310, respectively.

Here, for example, the vaporizing agent 390 may be applied to the non-coated portion located on the side of the central portion when the electrode 330 is wound. At this time, the vaporizing agent 390 may be applied to the non-coated portion located on the side of the center portion of the positive electrode sheet 320 and the negative electrode sheet 310 when wound. That is, on the non-coated portion side of the positive electrode sheet 320 and the non-coated portion side of the negative electrode sheet 310, which are positioned at the winding center portion at the uncoated portions formed on both sides of the wound positive electrode sheet 320 and the negative electrode sheet 310, Topic 390 can be applied.

As another example, the vaporizing agent 390 may be applied to the entire surface of the non-coated portion of the electrode 330. Here, the vaporizing agent 390 can be applied to all portions of the non-coated portion located on both sides of the positive electrode sheet 320 and the negative electrode sheet 310. That is, the uncoated portion side of the positive electrode sheet 320 and the uncoated portion side of the negative electrode sheet 310, which are located at the winding center portion at the time of winding the uncoated portions formed on both sides of the wound positive electrode sheet 320 and the negative electrode sheet 310, A vaporizing agent 390 can be applied to both the non-coated portion side of the positive electrode sheet 320 and the non-coated portion side of the negative electrode sheet 310 located at the outer periphery at the time of winding.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited thereto. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Further, the scope of protection of the invention will be clarified by the appended claims.

10: Secondary battery
11: Battery case
12: cap assembly
12a: Top cap
12b: Safety vents
12c: current blocking member
13: Positive lead
14: cathode lead
100, 200, 300: electrode assembly
110, 210: negative electrode sheet
111: cathode collector
112, 113: anode active material
120, 220: anode sheet
121: positive current collector
122, 123: cathode active material
130, 230:
131, 231: electrode collector
132, 232: electrode active material
140,150: Membrane
160: Negative electrode tab
170: positive tab
180: electrode tab
190, 190 ', 290,390:
H: space portion
A1, A2:

Claims (12)

Alternately stacked and assembled electrodes and separators; And
And a vaporizing agent which is applied to the electrode and generates a gas upon overcharging,
Wherein the electrode includes an electrode current collector and an electrode active material coated on the electrode current collector,
Wherein the vaporizing agent is applied to the non-coated portion of the electrode current collector to which the electrode active material is not applied. The method according to claim 1,
Wherein the vaporizing agent is electrolyzed at a predetermined voltage or higher to generate carbon dioxide (CO2). The method according to claim 1,
Wherein the vaporizing agent is made of lithium carbonate. The method according to claim 1,
Wherein the vaporizing agent is electrolyzed at a voltage of 4.5V or higher to generate gas. The method according to claim 1,
Further comprising: an electrode tab having one side attached to the non-coated portion of the electrode current collector and electrically connected to the electrode,
Wherein the vaporizing agent is applied to the non-coated portion so as to cover the one side portion of the electrode tab. The method according to claim 1,
Wherein the vaporizing agent is applied to a boundary portion between the electrode active material and the non-coated portion. The method of claim 6,
Wherein the vaporizing agent is applied so as to have the same height as the electrode active material and the electrode current collector. The method according to claim 1,
Wherein the vaporizing agent is applied so that the height from the electrode current collector is lower than that of the electrode active material. The method according to any one of claims 1 to 8,
Wherein the electrode and the separator are wound in a circular or oval shape,
The electrode active material is applied to the electrode current collector such that the uncoated portions are formed at both ends of the electrode current collector,
Wherein the vaporizing agent is applied to the non-coated portion located on the side of the central portion when the electrode is wound. The method of claim 9,
Wherein a space portion is formed on the center side of the electrode and the separator when the electrode and the separator are wound. The method of claim 9,
Wherein the electrode comprises a positive electrode sheet and a negative electrode sheet,
Wherein the positive electrode sheet includes a positive electrode collector and a positive electrode active material coated on the positive electrode collector,
Wherein the vaporizing agent is applied to the non-coated portion of the positive electrode current collector to which the positive electrode active material is not applied. The method according to any one of claims 1 to 8,
Wherein the vaporizing agent is applied to the entire surface of the non-coated portion to which the electrode active material is not applied, on one side or both sides of the electrode current collector.

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