This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0112395 dated September 19, 2018, and all contents disclosed in the documents of the corresponding Korean patent applications are incorporated as a part of this specification.
[2]
The present invention relates to an electrode assembly embedded in a secondary battery, and more particularly, to solve the problem occurring in the electrode assembly fixed with a tape after being manufactured by the conventional lamination and stacking method. It relates to an electrode assembly fixed by an extension extending from a separator or an extension extending from a current collector.
[3]
background
[4]
Secondary batteries, unlike primary batteries, are rechargeable, and have been widely researched and developed in recent years due to their small size and large capacity. As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing.
[5]
A secondary battery is configured by embedding an electrode assembly in a battery case (pouch, can, etc.). The electrode assembly mounted inside the battery case has a stacked structure of positive electrode/separator/negative electrode, so that repeated charging and discharging is possible.
[6]
1A is a side view illustrating a process of making an electrode assembly by a lamination & stacking process among conventional electrode assemblies, and FIG. 1B is a positive electrode 1, a separator 3, a negative electrode 2, a separator ( 3) is a side view showing a state in which a plurality of monocells 4 are stacked and then fixed by a tape 5, FIG. 1c is an electrode assembly manufactured by stacking a plurality of monocells on the tape 5 ) is a plan view of the fixed figure.
[7]
1A to 1C , in the lamination and stacking method, the positive electrode 1, the separator 3, the negative electrode 2, and the separator 3 are continuously unwound and supplied while being wound in a roll shape, and the separator In (3), the positive electrode (1) and the negative electrode (2) are cut to a certain size and moved, and passed through the laminating device. The positive electrode 1 and the negative electrode 2 are a positive electrode active material and a negative electrode active material on both sides of a positive electrode current collector (a portion marked with a slanted line in the center) and a negative electrode current collector (a portion marked with an x ​​in the center), respectively, as shown in FIG. 1B . This is the coated state.
[8]
While passing through the laminating device, the positive electrode 1, the separator 3, and the negative electrode 2 are bonded by heat and pressure, and the adjacent positive electrode 1 and the positive electrode 1 are adhered. One monocell (4) stacked in the order of anode (1), separator (3), cathode (2), separator (3) from the top by cutting between (between the adjacent cathode (2) and cathode (2)) It is produced continuously.
[9]
The monocells 4 are stacked by a predetermined number to manufacture an electrode assembly, and when the stacking is completed, each end of the tape 5 is adhered to each of the monocell of the uppermost layer and the monocell of the lowermost layer so as to be fixed.
[10]
However, in the fixing method of the monocells 4 using the tape 5 as described above, the ends of the tape 5 are additionally protruded from the uppermost layer and the lowermost layer to generate a thickness difference. In addition, when the tape 5 is attached, there may be a problem that a part of the edge of the negative electrode 2 (which is cut relatively larger than the positive electrode for stability) is folded.
[11]
Such a difference in thickness and folding of the cathode could increase the internal resistance and accelerate the degradation of the electrodes.
[12]
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[13]
Therefore, the main object of the present invention is to provide an electrode assembly in which the stacked monocells are stably fixed and the problems of folding and resistance increase of the negative electrode can be solved.
[14]
means of solving the problem
[15]
The present invention for achieving the object as described above, in an electrode assembly in which a negative electrode having a negative electrode active material coated on the surface of a negative electrode current collector, a separator, and a positive electrode coated with a positive electrode active material on the surface of the positive electrode current collector are repeatedly laminated, the positive electrode , a separator, a negative electrode, monocells stacked in the separator order; includes, wherein at least two or more monocells are stacked. And, it is characterized in that the fixing of the stacked monocells is made by surrounding the stacked monocells so that the extended part of the separator is placed on the outermost layer.
[16]
In an embodiment of the present invention, the monocell with the extension is a monocell stacked on the uppermost layer or the lowermost layer, and the separator with the extension is a separator placed between the cathode and the anode in the monocell (not a separator placed under the cathode).
[17]
The monocell has a rectangular shape, wherein the positive electrode tab extending from the positive electrode and the negative electrode tab extending from the negative electrode protrude in opposite directions, and the extended portion of the separator is perpendicular to the direction in which the positive electrode tab or the negative electrode tab protrudes. is expanded to
[18]
The monocell is adhered between the positive electrode and the separator and between the separator and the negative electrode.
[19]
As another embodiment, a monocell having a separator having an extension formed thereon is a monocell stacked on the uppermost layer, an anode is stacked on the separator in which an extension is formed, and the extension surrounds the entire electrode assembly so that the end of the separator is formed with the extension. If the top of the overlying anode is covered, a cathode is additionally stacked on it.
[20]
As another embodiment, a monocell having a separator having an extension formed thereon is a monocell stacked on the uppermost layer, and an anode is stacked on the separator in which an extension is formed, and a separator is additionally stacked on the anode stacked on the separator in which the extension is formed. An anode is additionally stacked thereon. That is, in this structure, the negative electrode is placed on the uppermost layer is the same as in the above embodiment, but there is a difference in that the separator is additionally stacked together.
[21]
As another embodiment, a monocell having a separator having an extension formed thereon is a monocell stacked on the uppermost layer, and a positive electrode is stacked on the separator in which an extension is formed, and the positive electrode stacked on the separator in which the extension is formed is only on one side of the positive electrode current collector. It is a single-sided positive electrode coated with a positive electrode active material, and is disposed so that the side on which the positive electrode active material is not applied faces upward.
[22]
In addition, the present invention additionally provides an embodiment that can be easily applied to a conventional electrode assembly. In this embodiment, a positive electrode, a separator, a negative electrode, and a separator include monocells stacked in this order, wherein at least two or more monocells are stacked, and a separator and a cathode are additionally stacked on top of the monocell stacked on the uppermost layer. In this case, the separator additionally stacked with the negative electrode is formed with an extended part extending to one side, and the extended part is fixed by surrounding the stacked monocells and the additionally stacked negative electrode.
[23]
As described above, the electrode assembly in which the extended part is formed and fixed to the separator surrounds the monocells on which the extended part is stacked, and then the ends are bonded and fixed at a predetermined point by applying heat and pressure. In addition, the expanded portion may be formed to have a thickness different from that of other portions of the separator in contact with the positive electrode or the negative electrode. Alternatively, the expanded portion may be manufactured to have a composition different from that of other portions of the separator in contact with the positive electrode or the negative electrode.
[24]
In addition, the expanded portion of the separator may surround the positive electrode and the negative electrode in a state in which a flat plate is inserted into one or both sides of the positive electrode and the negative electrode to stand vertically in the stacking direction.
[25]
At this time, the flat plate is made of a non-electrically conductive material, and when sealing is performed after the electrode assembly is inserted into the pouch, it is possible to prevent the separator from being rolled or pressed into the narrow portion of the pouch.
[26]
Alternatively, the expanded portion of the separator surrounds the monocells twice, and the flat plate is disposed such that the expanded portion is inserted between the first surrounding layer and the second surrounding layer, and is made of a metal material having thermal conductivity. In this case, the flat plate may function as a cooling plate that lowers the temperature by absorbing heat generated by the electrodes.
[27]
In addition, the present invention provides an extended portion (separately from the positive electrode tab and the negative electrode tab) formed on the current collector of the negative electrode and/or positive electrode constituting the unit cell instead of the extended portion of the separator, and fixed by bonding the extension portions. An electrode assembly is additionally provided.
[28]
That is, the electrode assembly of this embodiment is an electrode assembly in which a negative electrode having a negative electrode active material applied to the surface of the negative electrode current collector, a separator, and a positive electrode coated with a positive electrode active material on the surface of the positive electrode current collector are repeatedly stacked, the positive electrode, the separator, A negative electrode, monocells in which a separator is stacked in this order; includes, wherein at least two or more monocells are stacked, and at least two of the monocells each have a positive electrode extension part in which a positive electrode current collector is extended to one side. and a negative electrode extension in which the negative electrode current collector extends to the other side is formed, and the positive electrode extension portion and the negative electrode extension portion are bonded to each of the positive electrode extension portion and the negative electrode extension portion of another monocell, thereby fixing the stacked monocells.
[29]
In this case, each of the positive electrode extension part and the negative electrode extension part is formed separately from the positive electrode tab extended from the positive electrode and the negative electrode tab extended from the negative electrode.
[30]
The monocell has a rectangular shape, wherein the positive electrode tab and the negative electrode tab protrude in opposite directions, and the portion where the positive electrode extensions are joined and the portion where the negative extension portions are bonded protrude in opposite directions to each other, the positive electrode tab and It protrudes in a direction perpendicular to the negative electrode tab.
[31]
In another embodiment, the monocells in which the positive electrode extension part and the negative electrode extension part are formed are all stacked monocells, and in all monocells, the positive electrode extension part is bonded to the positive electrode extension parts and the negative electrode extension part is made to the negative extension parts.
[32]
As another embodiment, an anode is positioned on the uppermost layer of the monocell stacked on the uppermost layer, and a separator and a cathode are additionally stacked in order on the cathode positioned on the uppermost layer.
[33]
As another embodiment, the monocell in which the positive electrode extension part and the negative electrode extension part are formed is a monocell stacked on the uppermost layer and a monocell stacked on the lowermost layer, and a plurality of monocells are stacked between the monocell stacked on the uppermost layer and the monocell stacked on the lowermost layer. A sub-electrode assembly constructed by stacking mono cells is inserted, and in any one of the mono cells constituting the sub-electrode assembly, an extended part extended to one side is formed in one of the separators, and the extended part of the separator is a sub-electrode assembly It is characterized in that it surrounds all the monocells of the sub-electrode assembly so as to be placed on the outermost layer.
[34]
In the electrode assemblies in which the extension portion is additionally formed on the current collector as described above, the positive electrode extension portion in the positive electrode current collector is formed to have a thickness different from the portion coated with the positive electrode active material, and the negative electrode extension portion in the negative electrode collector portion is formed with the negative electrode active material coated portion and Different thicknesses may be formed.
[35]
In another embodiment, the monocell has a rectangular shape, a positive electrode tab extending from the positive electrode current collector is integrally formed with the positive electrode extension part, and the negative electrode tab extending from the negative electrode current collector is integrally formed with the negative electrode extension part, and the positive electrode The extension part has a shape protruding from two sides of the monocell, and the cathode extension part has a shape protruding from two opposite sides of the two sides from which the anode extension part protrudes.
[36]
In this case, a pattern groove recessed in a direction in which the positive electrode and the negative electrode are stacked may be formed in the portion where the positive electrode extension portions are bonded to each other and the negative electrode extension portions are bonded to each other.
[37]
In this case, the pattern groove formed in the portion where the anode electric parts are bonded to each other is disposed at a position symmetrical with the pattern groove formed in the portion where the cathode electric length parts are bonded to each other.
[38]
In addition, the above monocells may be bonded between the positive electrode and the separator and between the separator and the negative electrode.
[39]
Effects of the Invention
[40]
In the present invention having the above-described configuration, the expansion of the separator surrounds the stacked monocells, so that the stacked monocells are fixed, so the conventional tape is deleted, increasing the internal resistance due to the thickness difference and the folding of the cathode problem and electrode degradation problem can be solved.
[41]
Since the expanded portion is bonded at a predetermined point by applying heat and pressure, a smooth surface may be formed.
[42]
The expanded portion of the separator may be formed to have a thickness and/or composition different from other portions to improve adhesion and electrolyte impregnation.
[43]
The monocell has high stability due to adhesion between the positive electrode and the separator and between the separator and the negative electrode.
[44]
In addition, a flat plate is selectively inserted into the region surrounded by the extension to prevent the separator from being damaged when the pouch is sealed, and when the flat plate is made of a metal material, it is possible to increase the heat dissipation area to increase the cooling efficiency.
[45]
In addition, since the electrode assembly in which the positive electrode current collector and the negative electrode current collector are extended and fixed instead of the separator, the conventional tape is deleted, the problem of increasing the internal resistance due to the thickness difference and folding of the negative electrode and the electrode deterioration problem can be solved.
[46]
Brief description of the drawing
[47]
1A is a side view illustrating a process of manufacturing a monocell constituting an electrode assembly by a lamination and stacking process in a conventional electrode assembly;
[48]
1b is a side view showing a state in which a plurality of monocells 4 stacked in the order of a positive electrode 1, a separator 3, a negative electrode 2, and a separator 3 are stacked and then fixed by a tape 5;
[49]
1c is a plan view showing a state in which the electrode assembly manufactured by stacking a plurality of monocells in FIG. 1b is fixed by a tape 5;
[50]
Figure 2 is a side view showing a state in which an anode and a cathode are respectively stacked on the upper and lower sides of a separator in which an extension is formed to constitute a monocell.
[51]
3a is a view showing that a plurality of monocells are stacked according to Example 1 of the present invention, and the monocell 100 shown in FIG. 2 is stacked on the uppermost layer, and the separation membrane extension of the uppermost monocell surrounds all of the monocells. Side view shown.
[52]
Fig. 3B is a plan view of the state of Fig. 3A as viewed from the top down;
[53]
Figure 3c shows a plurality of monocells are stacked according to Example 3 of the present invention, the monocell 100 shown in FIG. 2 is stacked on the uppermost layer, and the separation membrane extension of the uppermost monocell surrounds all of the monocells and then tops it A side view showing that the negative electrode is additionally stacked.
[54]
Figure 3d shows a plurality of monocells 101 having no extension part are stacked according to Example 4 of the present invention, a separator having an extension part is stacked thereon, and a separator having an extension part and a negative electrode are additionally stacked as auxiliary units. A side view showing a state in which the expanded part of the separator surrounds the entire monocells after the negative electrode is stacked on the separator having the expanded part as a structure in which the expanded part is stacked.
[55]
FIG. 4a is a view showing that flat plates are inserted on both sides of monocells in the space surrounded by the expansion part in the state of FIG. 3a in accordance with the fifth embodiment of the present invention, in which the corners in the pouch come into contact with the pouch. side view.
[56]
FIG. 4b is a state in which the extension part rotates around the entire monocells two turns in the state of FIG. 3a according to the sixth embodiment of the present invention, and the flat plate is inserted between the overlapping parts of the extension part on both sides of the monocells; FIG. side view.
[57]
Figure 5a is a side view showing a state in which the positive electrode formed on one side of the anode extension portion, the separator, the negative electrode formed on the other side of the negative electrode extension portion, and the separator are stacked to form a monocell.
[58]
5B is a side view showing the stacked monocells of FIG. 5A, in which positive electrode extensions are bonded and fixed on one side, and negative electrode extensions are bonded and fixed on the other side according to Example 7 of the present invention.
[59]
Figure 5c shows a state in which the monocells of Figure 5a are stacked, according to Example 8 of the present invention, on one side the positive electrode extensions are bonded to each other and fixed, and on the other side, the negative electrode extensions are bonded and fixed, and then the separator and the uppermost layer A side view showing the additionally stacked anodes.
[60]
Figure 5d shows a state in which the monocells of Figure 5a are stacked on the uppermost layer and the lowermost layer, according to Example 9 of the present invention, the monocells stacked on the uppermost layer and the lowest layer are fixed by bonding the anode extensions from one side to the other. On the side, the negative electrode extensions are bonded to each other and fixed, and a sub-electrode assembly having the same structure as the electrode assembly shown in FIG. 3A is inserted between the monocells of the uppermost layer and the lowermost layer.
[61]
Fig. 6 is a plan view of the state of Fig. 5b from top to bottom;
[62]
7 is a plan view showing a deformed shape of an anode extension part and a cathode extension part;
[63]
8 is a plan view showing a state in which pattern grooves are formed in each of the anode extension part and the cathode extension part;
[64]
Modes for carrying out the invention
[65]
Hereinafter, based on the accompanying drawings, the present invention will be described in detail so that those of ordinary skill in the art can easily implement it. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.
[66]
In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar elements throughout the specification.
[67]
In addition, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor appropriately defines the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention based on the principle that it can be done.
[68]
The present invention relates to a negative electrode 20 coated with a negative active material 22 on the surface of a negative electrode current collector 21 , a separator 30 , and a positive electrode 10 coated with a positive electrode active material 12 on the surface of the positive electrode collector 11 . ) relates to an electrode assembly stacked repeatedly, so that the conventional fixing tape 5 can be deleted, either by a separator having an extension provided in one of the stacked monocells or by a separator having an extension on the current collector It is characterized in that the stacked structure is fixed by combining the cells. Hereinafter, embodiments according to the present invention will be described in more detail with reference to the accompanying drawings.
[69]
[70]
[Fixed by separator]
[71]
[72]
The present invention provides an electrode assembly that can be fixed by a separator (30) having an extension (31).
[73]
2 shows that the positive electrode 10 and the negative electrode 20 are respectively stacked on the upper side and the lower side of the separator 30 in which the extended part 31 is formed, and the separator 30 (of a conventional size) is stacked at the bottom. It is a side view showing the configuration of the monocell 100 . The electrode assembly fixed by the separator 30 includes one or more separators 30 in which the expansion part 31 is formed.
[74]
[75]
(Example 1)
[76]
3a is a view showing a plurality of monocells 100 and 101 are stacked according to Example 1 of the present invention, the monocell 100 shown in FIG. 2 is stacked on the uppermost layer, and the separation membrane extension of the uppermost monocell 100 is Reference numeral 31 is a side view showing the entire surrounding of the monocells 100 and 101, and FIG. 3B is a plan view of the state of FIG. 3A as viewed from the top down. As shown in FIGS. 3A and 3B, the electrode assembly according to Example 1 of the present invention is manufactured by stacking a plurality of monocells 100 and 101, except for the uppermost monocell 100, the remaining monocells ( 101) is stacked in the order of the positive electrode 10, the separator 30, the negative electrode 20, and the separator 30 from top to bottom, and heat and/or pressure are applied to the surfaces in contact with each other to form bonding. However, in the monocell 100 stacked on the uppermost layer, the positive electrode 10, the separator 30, the negative electrode 20, and the separator 30 are bonded in the same manner, but as shown in FIG. It has a structure in which the extended part 31 extending in length to one side is formed.
[77]
The extension part 31 is formed to have a length sufficient to surround the monocells 101 and the uppermost monocell 100 when all the monocells 100 and 101 of a predetermined number are stacked. In this embodiment, the monocell 100 having the extension 31 is shown to be stacked on the uppermost layer when stacked as an electrode assembly, but it is also possible to stack on the middle layer as well as the lowermost layer.
[78]
After the corresponding monocell (monocell having an expanded part) is stacked on the uppermost layer, the expanded part 31 is placed on the outermost layer as shown in FIG. It surrounds all of the stacked monocells 100 and 101 (so as to be placed on the uppermost monocell). And, the end thereof is adhered by applying heat and pressure to the upper surface of the uppermost monocell 100 (ie, the upper surface of the anode in the drawing) as shown in FIGS. 3A and 3B .
[79]
At this time, according to the thickness of the extension part 31, the end position of the extension part 31 may be adjusted to minimize or eliminate the height difference from the top surface. For example, if the thickness of the extended part 31 is very thin, the end of the extended part 31 may be configured to cover only half of the positive electrode placed on the uppermost layer, as shown in FIG. 3A , and the extended part 31 ), if the height difference according to the thickness occurs at a significant level, it will be preferable that the end of the extension part 31 is configured to cover the entirety of the positive electrode 10 placed on the uppermost layer or the coating portion of the positive electrode active material 12 (at this time, If the monocell is placed on the lowermost layer, the end of the extended portion 31 may be configured to cover the entire negative electrode 20 or the active material 22 coating portion of the negative electrode 20 placed on the uppermost layer).
[80]
On the other hand, the separator 30 is required to have an appropriate level of thickness to separate the anode 20 and the anode 10 . However, since the extended part 31 outside between the positive electrode 10 and the negative electrode 20 does not need to have the required thickness of the separator 30, in the separator 30 in which the extended part 31 is formed, the positive electrode 10 Alternatively, the portion in contact with the cathode 20 and the extension 31 may be formed to have different thicknesses.
[81]
Alternatively, the portion in contact with the positive electrode 10 or the negative electrode 20 and the expanded portion 31 in the separator 30 in which the expanded portion 31 is formed may be manufactured to have different compositions from each other. For example, the expanded portion 30 has the same thickness as the portion in contact with the positive electrode 10 or the negative electrode 20 , but is tougher, and additives added during manufacturing may be different to facilitate thermal bonding.
[82]
The uppermost monocell 100 has a rectangular or square shape as shown in FIG. 3b when viewed from above, a positive electrode tab 10a extending from the positive electrode 10 and a negative electrode tab 20a extending from the negative electrode 20 ) protrudes in opposite directions, and the extension 31 of the separator 30 extends in a direction perpendicular to the direction in which the positive electrode tab 10a or the negative electrode tab 20a protrudes (see FIGS. 3A and 3B ). ).
[83]
[84]
(Example 2)
[85]
On the other hand, in the electrode assembly, it is preferable to exclude the arrangement of the double-sided positive electrode on the outermost layer to minimize the precipitation of lithium (Li) contained in the positive electrode active material. In more detail, it is common that a single-sided anode or anode is disposed on the outermost layer to prevent the cathode active material from being exposed on the outermost layer. Accordingly, in the present invention, the configuration in which the cross-sectional anode is disposed on the outermost layer is provided as the second embodiment, and the configuration in which the cathode 20 is disposed on the outermost layer is provided as the second embodiment.
[86]
That is, in the electrode assembly according to the second embodiment, as in the electrode assembly of the first embodiment, the monocell 100 having the separator 20 in which the extension part 31 is formed is stacked on the uppermost layer, and the separator in which the extension part 31 is formed. The positive electrode 10 is stacked on the 30, and the uppermost positive electrode 10 stacked on the separator 30 on which the expansion part 31 is formed is the positive electrode active material 12 only on one surface of the positive electrode current collector 11. This is the coated single-sided anode. At this time, the positive electrode 10 of the uppermost layer is disposed so that the side on which the positive electrode active material 12 is not applied faces upward. That is, the electrode assembly according to Example 2 has the same configuration as the electrode assembly shown in FIG. 3A , but has a structure in which the positive electrode active material 12 above the positive electrode current collector 11 is deleted from the positive electrode stacked on the top.
[87]
[88]
(Example 3)
[89]
In the electrode assembly according to Example 3 of the present invention, the cathode 20 is additionally stacked in the electrode assembly of Example 1 so that the cathode 20 is positioned on the uppermost layer.
[90]
That is, FIG. 3c shows that a plurality of monocells 100 and 101 are stacked according to the second embodiment of the present invention, the monocell 100 shown in FIG. 2 is stacked on the uppermost layer, and the separation membrane of the uppermost monocell 100 is expanded. It is a side view showing a state in which the negative electrode 20 is additionally stacked thereon after the part 31 surrounds the entire monocells 100 and 101 . As shown, in the electrode assembly according to Example 3, in the structure of Example 1, the end of the extended part 31 of the separator 30 is wrapped so as to cover the uppermost anode 10 all over the cathode 20. This is further laminated. Optionally, in Example 3, if the end of the extended part 31 of the separator does not cover the uppermost anode 10 at all, the separator 30 is additionally stacked on the uppermost anode 10 and then the cathode 20 is stacked thereon It can also be configured to be
[91]
[92]
(Example 4)
[93]
In addition, the present invention provides a structure that can be more easily applied to a conventional (lamination and stacking method) electrode assembly as a fourth embodiment. Figure 3d shows a plurality of monocells 101 having no extension according to Example 4 of the present invention are stacked, and then expanded (instead of the monocells stacked on top in Examples 1, 2, and 3). Only the separator 30 having the portion 31 is stacked, and the negative electrode 20 is additionally stacked on the separator 30 having the expanded portion 31, and then the expanded portion 31 of the separator 30 is a monocell. It is a side view showing a state surrounding the entire field (101).
[94]
That is, in this embodiment, instead of removing the tape 5 from the electrode assembly shown in FIG. 1B , the separator 30 having the extended part 31 is additionally laminated on the uppermost layer, and the negative electrode 20 is laminated thereon. Next, the extension 31 is configured to enclose all of the monocells 101 and the additionally stacked uppermost negative electrode 20 to secure it.
[95]
[96]
(Example 5)
[97]
In addition, the present invention configures the structure of the electrode assembly more robustly, and the electrode assembly is embedded in the pouch 50 and the separator 30 is inserted into a narrow space when sealing (sealing) of the pouch 50 is made. In order to prevent damage, the structure in which the flat plate 40 is built is additionally provided as Examples 5 and 6.
[98]
That is, the electrode assembly according to the fifth embodiment is characterized in that the flat plate 40 is additionally mounted in the inner space surrounded by the expansion part 31 . Figure 4a is a view showing that the flat plate 40 is inserted on both sides of the monocells in the space surrounded by the expansion part 31 in the state of Figure 3a in accordance with the fifth embodiment of the present invention, the corner portion in the pouch 50 It is a side view showing a state in contact with the pouch 50 . Referring to the drawings, since the flat plate 40 is fixed in a vertically upright direction from the negative electrode 20 and the positive electrode 10, it can support the force pressed in the vertical direction when the pouch 50 is collected, and the extension part ( 31) can provide a function as a support when surrounded. Since the flat plate 40 has a flat plate shape, when it has such a shape, an effect of better alignment of the electrode assembly occurs.
[99]
On the other hand, in this embodiment, the flat plate 40 is made of a material without electrical conductivity to prevent a short circuit. That is, it may be formed of a kind of insulating plate. Occasionally, the inner aluminum of the pouch is exposed from the sealing part. When such an insulating plate is present, an issue in which the exposed aluminum and the electrode assembly come into contact with each other can be prevented.
[100]
[101]
(Example 6)
[102]
The electrode assembly provided in Example 6 in the present invention is the same as that of Example 5 in that a flat plate 40 is provided, but the flat plate 40 is made of a metal material having thermal conductivity, and the cathode 20 and the anode (10) provides the same function as a cooling plate that lowers the temperature by absorbing the heat generated by it. In addition, the flat plate 40 is disposed separately from the positive electrode 10 and the negative electrode 20 so as to prevent a short circuit caused by the flat plate 40 .
[103]
FIG. 4b is a state in which the extended part 31 wraps the entire monocells by two turns in the state of FIG. 3a according to the sixth embodiment of the present invention, and both sides of the monocells between the overlapping parts of the extended part 31 It is a side view showing a state in which the flat plate 40 is inserted. As shown, the expanded part 31 has a structure that wraps twice so that the flat plate 40 is disposed in a space separated from the positive electrode 10 and the negative electrode 20, and the flat plate 40 has the expanded part 31 It is located in the space created by the rotation of
[104]
In the structure of this embodiment, the flat plate 40 can increase the cooling performance of the negative electrode 20 and the positive electrode 30 without increasing the height of the electrode assembly.
[105]
When the flat plate 40 is vertically disposed in this way, the positive electrode current collector 11 and the negative electrode current collector 21 made of a metal material (even though they are separated by a separator, they are placed close to each other) so that heat is conducted to the flat plate 40 . Therefore, heat dissipation efficiency can be increased compared to a structure in which the flat plates 40 are stacked in the same direction as the electrodes. That is, the structure in which the flat plates 40 are stacked in the same direction as the electrode cannot absorb heat except the electrodes of the upper and lower layers, but the vertically erected structure has the ends of all the positive electrode current collectors 11 and the negative electrode current collector 21 . The cooling performance can be improved because they can be arranged in contact with each other.
[106]
[107]
[Fixed by current collector]
[108]
[109]
In addition, in the present invention, the positive electrode current collector 11 and the negative electrode current collector 21 are extended instead of the extended part 31 of the separator 30 to extend the extended portions 11a of the positive electrode current collectors 11 . A structure is provided in which the extended portions 21a of the negative electrode current collectors 21 are bonded to each other and fixed. 5a is a monocell 200 in which the positive electrode 10 having the positive electrode extension portion 11a formed on one side, the separator 30, the negative electrode 20 having the negative electrode extension portion 21a formed on the other side, and the separator 30 are stacked. The configuration is shown. That is, the electrode assembly having such a structure is characterized in that at least two monocells 200 having a positive electrode extension portion 11a and a negative electrode extension portion 21a are stacked, and the positive electrode extension portions 11a are bonded to each other and The negative electrode current collectors 21a are bonded to each other to be fixed.
[110]
At this time, the positive electrode extension portion 11a and the negative electrode extension portion 21a are formed separately from the positive electrode tab 10a and the negative electrode tab 20a as shown in FIG. 6 or are integrally integrated as shown in FIG. However, even when integrally formed, by increasing the widths of the positive electrode tab 10a and the negative electrode tab 20a (that is, by increasing the area in which the fastening is performed), a more stable fixing force can be provided.
[111]
[112]
(Example 7)
[113]
Figure 5b shows a state in which the monocells of Figure 5a are stacked, according to Example 7 of the present invention, on one side the positive extension parts 11a are bonded to each other and fixed, and on the other side, the negative extension parts 21a are bonded to each other and fixed This is a side view showing the
[114]
As shown, the electrode assembly in this embodiment is configured by stacking a plurality of monocells 200 in which the positive electrode 10, the separator 30, the negative electrode 20, and the separator 30 are stacked in this order. . And, in each of the monocells 200 of at least the uppermost layer and the lowermost layer of the monocells, the positive electrode extension portion 11a in which the positive electrode current collector 11 is extended to one side and the negative electrode current collector 21 are extended to the other side. and a negative electrode extension portion 21a, wherein the positive electrode extension portion 11a and the negative electrode extension portion 21a are laminated by bonding to each of the positive electrode extension portion 11a and the negative electrode extension portion 21a of another monocell 200 The fixed monocells are made. At this time, in this embodiment, each of the positive electrode extension portion 11a and the negative electrode extension portion 21a extends from the positive electrode tab 10a and the negative electrode 20 extended from the positive electrode 10 as shown in FIG. 6 . It is formed separately from the negative electrode tab 20a.
[115]
That is, in this embodiment, the monocell 200 has a rectangular shape, the positive electrode tab 10a and the negative electrode tab 20a protrude in opposite directions to each other, and the positive electrode extension portions 11a are joined to each other. The portion joined to the negative electrode extension portion 21a protrudes in opposite directions to each other and protrudes in a direction perpendicular to the positive electrode tab 10a and the negative electrode tab 20a.
[116]
In this embodiment, at least the monocells stacked on the uppermost layer and the lowermost layer are the monocells 200 in which the positive electrode extension portion 11a and the negative electrode extension portion 21a are formed. That is, in all of the stacked monocells 200 , a positive electrode extension portion 11a and a negative electrode extension portion 21a are formed, and all the positive electrode extension portions 11a are positive electrode extension portions 11a and all negative electrode extension portions 21a. ) may be configured such that the negative electrode extension portions 21a are bonded to each other.
[117]
On the other hand, the bonding of the positive electrode extension portion (11a) and the negative electrode extension portion (21a) is made by welding, but laser welding may also be possible, but depending on the thickness of the positive electrode current collector (11a) and the negative electrode current collector (21a) (usually a positive electrode) It would be preferable to proceed with ultrasonic welding (used as a welding method for the tab and the cathode tab).
[118]
[119]
(Example 8)
[120]
On the other hand, as described above, in the electrode assembly, the separator 30 and the negative electrode 20 are on the uppermost layer in this embodiment to exclude the arrangement of the double-sided positive electrode on the outermost layer for the purpose of minimizing the precipitation of lithium (Li) contained in the positive electrode active material. This is additionally placed.
[121]
Figure 5c shows a state in which the monocells of Figure 5a are stacked, on one side the positive electrode extensions 11a are bonded to each other and fixed, and on the other side, the negative electrode extension portions 21a are bonded to each other and fixed, and then the separator 30 on the uppermost layer ) and the negative electrode 20 are additionally stacked side view. As shown, the electrode assembly according to this embodiment has the same configuration as in Embodiment 7, but has a configuration in which a separator 30 and a cathode 20 are added one by one on top. That is, in this embodiment, the positive electrode 10 is located on the uppermost layer of the monocell 200 stacked on the uppermost layer, and the separator 30 and the negative electrode 20 are additionally stacked in order on the positive electrode 10 located on the uppermost layer. .
[122]
For this purpose, an auxiliary unit may be used. It may be a method of making an auxiliary unit in which one negative electrode and one separator are combined, and further stacking the auxiliary unit on the uppermost layer of the stacked monocells 200 .
[123]
[124]
(Example 9)
[125]
In addition, the present invention provides a structure in which the fixing method through the extension of the current collector and the fixing method through the extension of the separator are combined as a ninth embodiment. Figure 5d shows a state in which the monocells 200 of Figure 5a are stacked on the uppermost layer and the lowermost layer, the monocells 200 stacked on the uppermost layer and the lowermost layer are fixed by bonding the anode extensions 11a from one side to each other A side view showing a sub-electrode assembly having the same structure as that of the electrode assembly shown in FIG. 3A is inserted between the uppermost and lowermost monocells 200 of the uppermost and lowermost monocells 200 am.
[126]
In this embodiment, the monocell in which the positive electrode extension portion 11a and the negative electrode extension portion 21a are formed is a monocell 200 stacked on the uppermost layer and a monocell 200 stacked on the lowermost layer, and is stacked on the uppermost layer. A sub-electrode assembly formed by stacking a plurality of mono-cells is inserted between the mono-cell 200 and the mono-cell 200 stacked on the lowermost layer, and the sub-electrode assembly has the same configuration as the electrode assembly of Embodiment 1.
[127]
That is, in the sub-electrode assembly, the extended part 31 in which the separator 30 stacked on the uppermost layer is extended to one side is formed, and the extended part 31 of the separator 30 is formed in the sub-electrode assembly. All monocells of the sub-electrode assembly are surrounded so as to be placed on the outermost layer. In this configuration, the positive electrode extension 11a or the negative electrode extension portion 21a can be prevented from coming into contact with the individual electrodes (positive electrode or negative electrode) inside the electrode assembly. When the anode extension part 11a or the cathode extension part 21a comes into contact with individual electrodes inside the electrode assembly, a short-circuit accident may occur, which can be prevented.
[128]
On the other hand, in the electrode assembly provided in Examples 7 to 9, which is fixed by the extension formed on the current collector, each of the positive electrode extension portion 11a and the negative electrode extension portion 21a is the same, so that the same ones are collected and joined. , it is possible to provide a fixing force separately from the positive electrode tab 10a and the negative electrode tab 20a that are individually collected and bonded as described above.
[129]
In addition, in the above embodiments, the positive electrode current collector 11 and the negative electrode current collector 21 are designed according to the thickness and characteristics of the applied active materials 12 and 22 and are manufactured according to the required conditions of the electrode assembly. was not easy to change. However, the positive electrode extension portion 11a and the negative electrode extension portion 21a to which the respective positive electrode active material 12 and negative electrode active material 22 are not applied are relatively less in terms of thickness constraint.
[130]
Therefore, in the present invention, in the positive electrode current collector 11 and the negative electrode current collector 21, each of the positive electrode extension portion 11a and the negative electrode extension portion 21a is formed to have a different thickness from the portion to which the active materials 12 and 22 are applied. can That is, the positive electrode extension portion 11a and the negative electrode extension portion 21a may be made thinner than the portion to which the active material is applied so that the portion to be joined is thin or bent in the vertical direction after bonding. Conversely, it may be manufactured to be thicker than the portion coated with the active material so as to more strongly support the movement of the stacked monocells.
[131]
6 is a plan view of the state of FIG. 5 viewed from the top down, FIG. 7 is a plan view showing a deformed shape of the positive electrode extension part and the negative electrode extension part, and FIG. 8 is a pattern groove in each of the positive electrode extension part and the negative electrode extension part This is a plan view showing the formed state.
[132]
As shown, the monocells 200 according to Embodiments 7 to 9 also have a rectangular or square shape like the monocell 100 of Embodiment 1.
[133]
At this time, as shown in FIG. 6 , the positive electrode tab 10a extended from the positive electrode 10 and the negative electrode tab 20a extended from the negative electrode protrude in opposite directions, and the positive electrode extension portions 11a are bonded to each other. The portion joined to the negative electrode extension portion 21a protrudes in opposite directions to each other, and protrudes in a direction perpendicular to the positive electrode tab 10a and the negative electrode tab 20a. Like the positive electrode tab 10a and the negative electrode tab 20a, the positive electrode extension portion 11a and the negative electrode extension portion 21a also extend from the positive electrode current collector 11 and the negative electrode current collector 21, so that the positive electrode extension portion 11a and the negative electrode current collector 21 are extended. The part 11a and the negative electrode extension part 21a may also function as terminals through which a current moves as an electrode assembly. That is, the positive electrode extension portion 11a and the negative electrode extension portion 21a may be electrically connected to an external device instead of the positive electrode tab 10a and the negative electrode tab 20a.
[134]
In addition, since the positive electrode tab 10a and the negative electrode tab 20a and the positive electrode extension part 11a and the negative electrode extension part 21a may provide the same function, they may be integrated into one without separate distinction. That is, as shown in FIG. 7 , the positive electrode tab 10a extended from the positive electrode current collector 11 and the positive electrode extension portion 11a are integrally formed, and the negative electrode tab 20a extended from the negative electrode current collector 21 is It may be formed integrally with the negative electrode extension portion 21a (conversely, any one of the positive electrode tab and the positive electrode extension portion and any one of the negative electrode tab and the negative electrode extension portion may be omitted).
[135]
At this time, in this embodiment, the anode extension 11a has a shape protruding from two sides of the monocell 200 to ensure the fixing force of each monocell 200 (to provide sufficient fastening force), and the cathode extension portion Reference numeral 21a has a shape in which the anode extension portion 11a protrudes from two opposite sides of the protruding side.
[136]
In addition, in the portion where the positive electrode extension portions 11a are bonded to each other and the negative electrode extension portions 21a are bonded to each other, a pattern groove is dented along the direction in which the positive electrode 10 and the negative electrode 20 are stacked (ie, the thickness direction). (11b, 21b) may be formed. That is, as shown in FIG. 8 , a plurality of pattern grooves 11b and 21b may be formed in a portion where the positive electrode extension portions 11a are bonded to each other and a portion where the negative electrode extension portions 21a are bonded to each other. These pattern grooves 11b and 21b may be used as spaces into which devices providing additional functions, such as coolant, are inserted before the electrode assembly is embedded in the pouch. In this embodiment, the pattern groove 11b formed in the portion where the positive electrode electric length parts 11a are bonded to each other is disposed at a position symmetrical with the pattern groove 21b formed in the portion where the negative electrode extension parts 21a are bonded to each other. can
[137]
[138]
The present invention having the above-described technical characteristics is a configuration in which the extended part 31 of the separator 30 surrounds the stacked monocells so that the stacked monocells are fixed, and each anode extension part 11a and Since the negative electrode extension portions 21a are coupled to each other to provide a configuration in which the monocells are fixed, the conventional tape is deleted to solve the problem of increasing the internal resistance due to the thickness difference and folding of the negative electrode and the electrode deterioration problem.
[139]
Since the expanded part 31 is adhered at a predetermined point by applying heat and pressure, a smooth surface may be formed.
[140]
The extended part 31 of the separator may be formed differently from other parts in thickness and/or composition to improve adhesion and electrolyte impregnation, and the anode extension part 11a and the cathode extension part 21a are each It is configured to have a different thickness from other parts (the part to which the active material is applied), so that the welding performance and the size of the part to be welded can be variously configured as needed.
[141]
The monocell has high stability due to adhesion between the positive electrode and the separator and between the separator and the negative electrode.
[142]
In addition, the flat plate 40 may be selectively inserted in the region surrounded by the expansion part 31 to increase cooling efficiency and supporting power. In addition, since the coolant can be selectively inserted into the portion where the pattern grooves 11b and 21b are formed, the cooling efficiency can be increased.
[143]
In addition, as the electrode assembly having the above technical characteristics is provided, the present invention may additionally provide a secondary battery in which the electrode assembly according to the present invention is embedded in a pouch and a secondary battery module mounted so that a plurality of the secondary batteries are electrically connected. have.
[144]
In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is described below with the technical idea of ​​the present invention by those of ordinary skill in the art to which the present invention pertains. Various implementations are possible within the scope of equivalents of the claims to be made.
Claims
[Claim 1]
In an electrode assembly in which a negative electrode coated with a negative electrode active material on the surface of a negative electrode current collector, a separator, and a positive electrode coated with a positive electrode active material on the surface of a positive electrode collector are repeatedly stacked, monocells stacked in the order of a positive electrode, a separator, a negative electrode, and a separator Including, wherein at least two or more monocells are stacked, one of the monocells has an extended part extended to one side is formed in one of the separators, and the extended part of the separator is stacked so that the extended part is placed on the outermost layer An electrode assembly in which the stacked monocells are fixed by surrounding the monocells.
[Claim 2]
The electrode assembly according to claim 1, wherein the monocell with the extended part is a monocell stacked on the uppermost layer or the lowest layer, and the separator with the extended part is a separator placed between the cathode and the anode in the monocell.
[Claim 3]
The method of claim 1, wherein the monocell has a rectangular shape, the positive electrode tab extending from the positive electrode and the negative electrode tab extending from the negative electrode protrude in opposite directions, and the extended portion of the separator has a positive electrode tab or a negative electrode tab protruding. An electrode assembly, characterized in that extended in a direction perpendicular to the direction.
[Claim 4]
The electrode assembly according to claim 1, wherein the monocell is bonded between the positive electrode and the separator and between the separator and the negative electrode.
[Claim 5]
The separator according to claim 1, wherein the monocell having a separator having an extension formed thereon is a monocell stacked on the uppermost layer, a positive electrode is stacked on the separator having an extension formed thereon, and the extension part surrounds the entire electrode assembly so that an end thereof is a separator in which the extension is formed. When covering the top of the positive electrode placed on top of the electrode assembly, characterized in that the negative electrode is additionally laminated thereon.
[Claim 6]
According to claim 1, wherein the monocell having a separator formed with an extension is a monocell stacked on the uppermost layer, and an anode is stacked on the separator on which the extension is formed, and a separator is additionally stacked on the anode stacked on the separator on which the extension is formed. and an electrode assembly, characterized in that an anode is additionally stacked thereon.
[Claim 7]
According to claim 1, wherein the monocell having a separator formed with an extension is a monocell stacked on the uppermost layer, and a positive electrode is stacked on the separator on which the extension is formed, and the positive electrode stacked on the separator on which the extension is formed is one surface of the positive electrode current collector. An electrode assembly, characterized in that it is a single-sided positive electrode coated with a positive electrode active material only on the surface, and the side on which the positive electrode active material is not applied faces upward.
[Claim 8]
In an electrode assembly in which a negative electrode coated with a negative electrode active material on the surface of a negative electrode current collector, a separator, and a positive electrode coated with a positive electrode active material on the surface of a positive electrode collector are repeatedly stacked, monocells stacked in the order of a positive electrode, a separator, a negative electrode, and a separator Including, wherein at least two or more monocells are stacked, and a separator and a negative electrode are additionally stacked in this order on the monocell stacked on the uppermost layer, and the separator additionally stacked with the negative electrode is formed with an extended extended to one side, and , An electrode assembly in which the extension is fixed by enclosing the stacked monocells and the additionally stacked negative electrode.
[Claim 9]
[10] The electrode assembly according to any one of claims 1 to 9, wherein the extension part surrounds the stacked monocells, and then the ends are attached and fixed at a predetermined point by applying heat and pressure.
[Claim 10]
The electrode assembly according to any one of claims 1 to 9, wherein the expanded portion is formed to have a thickness different from that of other portions of the separator in contact with the positive electrode or the negative electrode.
[Claim 11]
The electrode assembly according to any one of claims 1 to 9, wherein the expanded portion is manufactured to have a composition different from that of other portions of the separator in contact with the positive electrode or the negative electrode.
[Claim 12]
10. The method of any one of claims 1 to 9, wherein the expanded portion of the separator is surrounded by a flat plate inserted into one or both sides of the positive electrode and the negative electrode so as to stand vertically in the stacking direction in which the positive and negative electrodes are stacked. Electrode assembly, characterized in that.
[Claim 13]
The electrode assembly according to claim 12, wherein the flat plate is made of a non-electrically conductive material.
[Claim 14]
13. The method of claim 12, wherein the expanded part of the separator surrounds the monocells twice, and the flat plate is disposed such that the expanded part is inserted between the first and second surrounding layers, and is made of a metal material having thermal conductivity. Electrode assembly, characterized in that.
[Claim 15]
In an electrode assembly in which a negative electrode coated with a negative electrode active material on the surface of a negative electrode collector, a separator, and a positive electrode coated with a positive electrode active material on the surface of a positive electrode collector are repeatedly stacked, a monocell in which a positive electrode, a separator, a negative electrode, and a separator are sequentially stacked Including; wherein at least two or more of the monocells are stacked, and at least two of the monocells each have a positive electrode extension in which a positive electrode current collector extends to one side and a negative electrode current collector in an extended direction to the other side. An electrode assembly in which a negative electrode extension portion is formed, and the anode extension portion and the negative electrode extension portion are bonded to each of the positive electrode extension portion and the negative electrode extension portion of another monocell, whereby the stacked monocells are fixed.
[Claim 16]
The electrode assembly according to claim 15, wherein each of the positive electrode extension portion and the negative electrode extension portion is formed separately from the positive electrode tab extending from the positive electrode and the negative electrode tab extending from the negative electrode.
[Claim 17]
The method according to claim 16, wherein the monocell has a rectangular shape, wherein the positive electrode tab and the negative electrode tab protrude in opposite directions, and the portion bonded to the positive electrode extension portions and the portion bonded to the negative electrode extension portions are opposite to each other An electrode assembly, characterized in that it protrudes in a direction perpendicular to the positive electrode tab and the negative electrode tab.
[Claim 18]
[16] The method of claim 15, wherein the monocells in which the positive electrode extension part and the negative electrode extension part are formed are all stacked monocells, and in all monocells, the positive electrode extension part is bonded to the positive electrode extension part and the negative electrode extension part to the negative electrode extension parts. electrode assembly.
[Claim 19]
The electrode assembly according to claim 15, wherein an anode is positioned on the uppermost layer of the monocell stacked on the uppermost layer, and a separator and a cathode are additionally stacked in order on the cathode positioned on the uppermost layer.
[Claim 20]
[16] The method of claim 15, wherein the monocell with the positive electrode extension and the negative electrode extension is formed with a monocell stacked on the uppermost layer and a monocell stacked on the lowermost layer, and a plurality of monocells are stacked between the monocell stacked on the uppermost layer and the monocell stacked on the lowermost layer. A sub-electrode assembly composed of stacked monocells is inserted, and in any one of the monocells constituting the sub-electrode assembly, an extended part extending to one side is formed in one of the separators, and the extended part of the separator is a sub-electrode An electrode assembly, characterized in that it surrounds all the monocells of the sub-electrode assembly so as to be placed on the outermost layer in the assembly.
[Claim 21]
The method according to claim 15, wherein the positive electrode extension portion of the positive electrode current collector is formed to have a thickness different from that of the portion coated with the positive electrode active material, and the negative electrode extension portion of the negative electrode current collector is formed to have a different thickness from the portion coated with the negative electrode active material. electrode assembly
[Claim 22]
16. The method of claim 15, wherein the monocell has a rectangular shape, a positive electrode tab extending from the positive electrode current collector is integrally formed with the positive electrode extension portion, and the negative electrode tab extending from the negative electrode current collector is formed integrally with the negative electrode extension portion, wherein the An electrode assembly, characterized in that the positive electrode extension portion has a shape protruding from two sides of the monocell, and the negative electrode extension portion has a shape projecting from two opposite sides of the two sides from which the positive electrode extension portion protrudes.
[Claim 23]
23. The electrode according to any one of claims 15 to 22, wherein a pattern groove recessed in a direction in which the positive electrode and the negative electrode are stacked is formed in the portion where the positive electrode extension portions are bonded to each other and the negative electrode extension portions are bonded to each other. assembly.
[Claim 24]
24. The electrode assembly according to claim 23, wherein the pattern groove formed in the portion where the anode electric parts are joined to each other is disposed at a position symmetrical with the pattern groove formed in the portion where the cathode electric length parts are joined to each other.
[Claim 25]
The electrode assembly according to claim 23, wherein the monocell is bonded between the positive electrode and the separator and between the separator and the negative electrode.
[Claim 26]
A secondary battery in which the electrode assembly according to any one of claims 1, 8, and 15 is embedded in a pouch.
[Claim 27]
A secondary battery module mounted so that a plurality of secondary batteries according to claim 26 are electrically connected.