阅读说明：本技术 电极组件、包含其的二次电池、用于制造二次电池的方法及电池组 (Electrode assembly, secondary battery including the same, method for manufacturing the secondary battery, and battery pack ) 是由 李菅菩 安昶范 罗胜昊 李修镐 李学受 于 2019-11-27 设计创作，主要内容包括：本发明涉及一种电极组件。电极组件包括：基本单元,该基本单元中交替地层叠有多个电极和多个隔膜,该基本单元具有一个电极层叠在最上端的结构；以及辅助单元,该辅助单元设置有分隔片,该分隔片设置于基本单元的最上端侧,其中,该分隔片包括：分隔部,该分隔部设置于基本单元的最上端侧；以及侧表面保护部,该侧表面保护部与分隔部的每个侧表面连接并折叠以与基本单元的侧部接触,从而覆盖基本单元的侧部。(The present invention relates to an electrode assembly. The electrode assembly includes: a base unit in which a plurality of electrodes and a plurality of separators are alternately stacked, the base unit having a structure in which one electrode is stacked on the uppermost end; and an auxiliary unit provided with a partition sheet provided at an uppermost end side of the base unit, wherein the partition sheet includes: a partition portion provided on the uppermost end side of the base unit; and a side surface protecting part connected to each side surface of the partition part and folded to be in contact with the side of the base unit, thereby covering the side of the base unit.)

1. An electrode assembly, the electrode assembly comprising:

a basic unit in which a plurality of electrodes and a plurality of separators are alternately stacked, the basic unit having a structure in which one electrode is stacked at the uppermost end; and

an auxiliary unit provided with a partition provided at an uppermost end side of the base unit, wherein the partition includes:

a partition portion provided on the uppermost end side of the base unit; and

a side surface protecting part connected to each side surface of the partition part and folded to be in contact with a side of the base unit so as to cover the side of the base unit.

2. The electrode assembly according to claim 1, wherein the side surface protection part is bonded to each side surface of each separator provided in the base unit.

3. The electrode assembly according to claim 2, wherein an adhesive force between the side surface protective part and the side surface of the separator is smaller than an adhesive force between the electrode provided in the base unit and the separator.

4. The electrode assembly according to claim 2, wherein the base unit and the auxiliary unit are adhered to each other with an adhesive force smaller than an adhesive force between the electrode disposed in the base unit and the separator, or are adjacent to each other without the adhesive force.

5. The electrode assembly according to claim 1, wherein the separator further comprises a bottom surface protector connected to lower end surfaces of the side surface protectors and folded to contact the lowermost end surfaces of the base units.

6. The electrode assembly according to claim 5, wherein a part or the entirety of the bottom surface protective part is bonded to the lowermost end surface of the base unit.

7. The electrode assembly according to claim 1, wherein the separator further comprises a surface protector connected to each of two side surfaces of the side surface protector and folded to contact each of front and back surfaces of the base unit.

8. The electrode assembly of claim 1, wherein the separator is made of a synthetic resin material.

9. The electrode assembly according to claim 1, further comprising a fixing band attached in a manner of surrounding the base unit and the auxiliary unit.

10. The electrode assembly according to claim 1, wherein the auxiliary unit further comprises an electrode disposed at an uppermost end side of the separator.

11. The electrode assembly according to claim 1, wherein a cutting line is formed on a boundary between the partition and the side surface protection part.

12. A secondary battery, comprising:

an electrode assembly; and

a battery case configured to receive the electrode assembly,

wherein the electrode assembly includes:

a basic unit in which a plurality of electrodes and a plurality of separators are alternately stacked, the basic unit having a structure in which one electrode is stacked at the uppermost end; and

an auxiliary unit provided with a partition provided at an uppermost end side of the base unit, wherein the partition includes:

a partition portion provided on the uppermost end side of the base unit; and

a side surface protecting part connected to each side surface of the partition part and folded to be in contact with the side of the base unit so as to cover the side of the base unit.

13. The secondary battery according to claim 12, wherein the side surface protection parts are cut off from the partition part when the electrode assembly is received in the battery case.

14. A method for manufacturing a secondary battery, comprising the steps of:

(A) a step of alternately stacking a plurality of electrodes and a plurality of separators to manufacture a basic unit, wherein one electrode is stacked on the uppermost end of the basic unit;

(B) a secondary cell completion step of cutting the separation film to manufacture a secondary cell provided with a partition having a size corresponding to each separator and a side surface protection part connected to each of both side surfaces of the separator to manufacture a separation sheet;

(C) a step of positioning the partition of the auxiliary unit at an uppermost end side of the base unit and folding the side surface protection part with respect to the partition, and then positioning the side surface protection part on each side surface of the base unit to manufacture an unfinished electrode assembly;

(D) a step of simultaneously pressing the uppermost end and the lowermost end of the unfinished electrode assembly to bond the auxiliary unit and the base unit to each other;

(E) a step of attaching a fixing tape in a manner to surround the unfinished electrode assembly and thereby manufacturing a finished electrode assembly; and

(F) a step of accommodating the finished electrode assembly in a battery case and sealing an edge surface of the battery case to manufacture a finished secondary battery.

Technical Field

The present invention relates to an electrode assembly, a secondary battery including the same, a method for manufacturing the secondary battery, and a battery pack, and more particularly, to an electrode assembly having a structure to prevent foreign substances from entering into a side surface, a secondary battery including the electrode assembly, a method for manufacturing the secondary battery, and a battery pack.

Background

In general, a secondary battery refers to a chargeable and dischargeable battery, unlike a primary battery that cannot be charged. Secondary batteries are being widely used in high-tech electronic fields such as mobile phones, notebook computers, and camcorders.

The secondary battery may be variously classified according to the structure of the electrode assembly. For example, the secondary battery may be classified into a laminate type structure, a jelly-roll type structure, or a laminate/folding type structure.

The laminate-type secondary battery includes an electrode assembly and a pouch accommodating the electrode assembly, and the electrode assembly has a structure in which electrodes and separators are separately laminated. In addition, a lamination process is performed on the electrode assembly having the laminate structure as described above to improve the bonding force.

However, in the transfer step of the lamination process, there is a problem in that foreign substances such as electrode powder enter into the side surfaces of the electrode assembly. As a result, quality problems such as low voltage failure may occur due to foreign substances entering into the side surfaces of the electrode assembly.

Disclosure of Invention

Technical problem

An object of the present invention is to provide an electrode assembly that blocks foreign substances and electrode powder from entering into a side surface of the electrode assembly to prevent low-voltage failure, thereby improving quality, a secondary battery including the electrode assembly, a method for manufacturing the secondary battery, and a battery pack.

Technical scheme

An electrode assembly according to a first embodiment of the present invention for achieving the above object includes: a base unit in which a plurality of electrodes and a plurality of separators are alternately stacked, the base unit having a structure in which one electrode is stacked on the uppermost end; and an auxiliary unit provided with a partition sheet provided at an uppermost end side of the base unit, wherein the partition sheet includes: a partition portion provided on the uppermost end side of the base unit; and a side surface protecting part connected to each side surface of the partition part and folded to be in contact with the side of the base unit to cover the side of the base unit.

The side surface protection part may be adhered to each side surface of each diaphragm provided in the base unit.

The adhesive force between the side surface protection part and the side surface of the separator may be less than the adhesive force between the electrode provided in the base unit and the separator.

The base unit and the auxiliary unit may be adhered to each other with an adhesive force smaller than that between the electrode provided in the base unit and the separator, or adjacent to each other without the adhesive force.

The separator may be made of a synthetic resin material. The electrode assembly may further include a fixing band attached in a manner of surrounding the base unit and the auxiliary unit.

The auxiliary unit may further include an electrode disposed at an uppermost end side of the separator.

A cutting line may be formed on a boundary between the partition and the side surface protection part.

The area of the side surface protection part may be larger than the area of the side surface of the base unit.

A secondary battery according to a second embodiment of the present invention includes: an electrode assembly; and a battery case configured to receive the electrode assembly, wherein the electrode assembly includes: a base unit in which a plurality of electrodes and a plurality of separators are alternately stacked, the base unit having a structure in which one electrode is stacked on the uppermost end; and an auxiliary unit provided with a partition sheet provided at an uppermost end side of the base unit, wherein the partition sheet includes:

a partition portion provided on the uppermost end side of the base unit; and a side surface protecting part connected to each side surface of the partition part and folded to be in contact with the side of the base unit to cover the side of the base unit.

A method of manufacturing a secondary battery according to a second embodiment of the present invention includes: (A) a step of alternately stacking a plurality of electrodes and a plurality of separators to manufacture a basic unit, wherein one electrode is stacked on the uppermost end of the basic unit; (B) an auxiliary unit completion step of cutting the separation film to manufacture an auxiliary unit provided with a partition having a size corresponding to each of the separators and a side surface protection part connected to each of both side surfaces of the separator to manufacture a separation sheet; (C) a step of positioning the separation sheet of the auxiliary unit at the uppermost end side of the base unit and folding the side surface protection part with respect to the separation part, and then positioning the side surface protection part on each side surface of the base unit to manufacture an unfinished electrode assembly; (D) a step of simultaneously pressing the uppermost end and the lowermost end of the unfinished electrode assembly to bond the auxiliary unit and the base unit to each other; (E) a step of attaching a fixing tape to surround the unfinished electrode assembly and thereby manufacturing a finished electrode assembly; and (F) a step of accommodating the finished electrode assembly in a battery case and sealing an edge surface of the battery case to manufacture a finished secondary battery.

A battery pack according to a third embodiment of the present invention includes one or more secondary batteries and a battery case configured to accommodate the one or more secondary batteries. Wherein the secondary battery includes an electrode assembly and a battery case configured to accommodate the electrode assembly, wherein the electrode assembly includes: a base unit in which a plurality of electrodes and a plurality of separators are alternately stacked, the base unit having a structure in which one electrode is stacked on the uppermost end; and an auxiliary unit provided with a partition sheet provided at an uppermost end side of the base unit, wherein the partition sheet includes: a partition portion provided on the uppermost end side of the base unit; and a side surface protecting part connected to each side surface of the partition part and folded to be in contact with the side of the base unit to cover the side of the base unit.

The electrode assembly according to the fourth embodiment of the present invention further includes an electrode disposed at the uppermost end of the separator of the auxiliary unit.

An electrode assembly according to a fifth embodiment of the present invention includes a separator, wherein the separator further includes a bottom surface protector connected to a lower end surface of the side surface protector and folded to contact a lowermost end surface of the base unit.

A part or the whole of the bottom surface guard may be bonded to the lowermost end surface of the base unit.

The separator may further include a surface protector connected to each of both side surfaces of the side surface protectors and folded to contact each of the front and back surfaces of the base unit.

The electrode assembly according to the sixth embodiment of the present invention includes side surface protectors, wherein the lower side surface protectors are cut from the partitions when the electrode assembly is received in the battery case.

Technical effects

The electrode assembly of the present invention may include a base unit and an auxiliary unit. The auxiliary unit may include a partition sheet, and the partition sheet may include a partition portion disposed at an uppermost end side of the base unit and a side surface protection portion covering a side portion of the base unit. Therefore, it is possible to block foreign substances and electrode powder from entering the side surfaces of the base unit to prevent low voltage failures from occurring, thereby improving quality.

Drawings

Fig. 1 is a perspective view of an electrode assembly according to a first embodiment of the present invention.

Fig. 2 is a side view of an electrode assembly according to a first embodiment of the present invention.

Fig. 3 is an enlarged view of a portion "a" shown in fig. 2.

Fig. 4 is a side view of an electrode assembly with a fixing tape attached thereto according to a first embodiment of the present invention.

Fig. 5 is a sectional view of a secondary battery according to a second embodiment of the present invention.

Fig. 6 is a flowchart illustrating a method for manufacturing a second battery according to a second embodiment of the present invention.

Fig. 7 is a process diagram illustrating a method for manufacturing a second battery according to a second embodiment of the present invention.

Fig. 8 is a schematic side view of a battery pack according to a third embodiment of the present invention.

Fig. 9 is a sectional view illustrating an auxiliary unit of an electrode assembly according to a fourth embodiment of the present invention.

Fig. 10 is a perspective view of an electrode assembly according to a fifth embodiment of the present invention.

Fig. 11 is a development view of the separator of fig. 10.

Fig. 12 is a front view of fig. 10.

Fig. 13 is a perspective view of an electrode assembly according to a sixth embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in such a manner that those skilled in the art to which the present invention pertains can easily implement the technical idea of the present invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, any unnecessary description of the invention will be omitted for clarity, and like reference numerals in the drawings denote like elements.

[ electrode Assembly according to the first embodiment of the present invention ]

As shown in fig. 1 to 3, an electrode assembly 100 according to a first embodiment of the present invention includes a base unit 110 and an auxiliary unit 120.

Basic unit

In the basic unit having the structure, a plurality of electrodes 111 and a plurality of separators 112 are alternately stacked. Specifically, the base unit 110 has a structure in which electrodes are stacked on the uppermost end.

That is, in the base unit 110, the plurality of electrodes 111 and the plurality of separators 112 are alternately stacked in the vertical direction. Therefore, the basic unit 110 has a structure in which the electrode 111 is stacked at the uppermost end and the separator 112 is stacked at the lowermost end.

Here, the plurality of electrodes 111 includes a first electrode and a second electrode. Therefore, in the basic unit 110, a four-layer structure in which the first electrode, the separator, the second electrode, and the separator are stacked is stacked at once or repeatedly stacked.

Each electrode 111 includes a collector (collector) and electrode active material layers applied to both side surfaces of the collector.

Also, the first electrode may be a negative electrode and the second electrode may be a positive electrode, or vice versa.

Auxiliary unit

The auxiliary unit 120 includes a partition plate 122 disposed at the uppermost end side of the base unit 110. The separation sheet 122 prevents foreign substances from entering the side surfaces of the base unit 110 to prevent the side surfaces of the base unit 110 from being contaminated.

For example, the separator 122 includes: a partition portion 122a provided on the uppermost end side of the base unit 110; and a side surface protecting part 122b connected to each side surface of the partition part 122a and folded to be in contact with the side of the base unit 110, thereby covering the side of the base unit 110. That is, in the separator 122, a partition portion 122a is disposed at the uppermost end side of the base unit 110 to protect the electrode disposed at the uppermost end of the base unit 110, and a side surface protection portion 122b is connected to each of both side surfaces of the partition portion 122 a. The side surface protection part 122b is folded toward each side surface of the base unit 110 to prevent the side surface of the base unit 110 from being exposed to the outside.

Therefore, the auxiliary unit 120 can prevent foreign substances from entering the side surfaces of the base unit through the separation sheet 122, thereby preventing quality problems such as low voltage failures from occurring.

Since the partition plate 122 only needs to prevent foreign substances from entering into the side surface of the base unit 110, the partition plate 122 may be made of an inexpensive material. That is, the separator 122 may be made of a synthetic resin material, particularly, a polyethylene terephthalate (PET) material, to improve the convenience of purchase.

Specifically, the partition portion 122a and the side surface protection portion 122b are integrally formed to easily achieve the manufacturing and prevent the partition portion 122a and the side surface protection portion 122b from being separated from each other due to external impact.

As shown in fig. 3, the side surface protection part 122b may be adhered to the side surface of the diaphragm 112 provided in the base unit 110 to stably protect the side surface of the base unit 110 by the side surface protection part 122 b.

For example, heat is applied to the outer surface (the right surface when viewed in fig. 3) of the side surface protection part 122b in a state where the back surface (the left surface when viewed in fig. 3) of the side surface protection part 122b and the side surface of the diaphragm 112 provided in the base unit 110 are in close contact with each other. As a result, the diaphragm 112 and the side surface protective part 122b can be bonded while the coating having the adhesive force is melted. The diaphragm 112 and the side surface protective part 122b may be adhered to each other by using an adhesive to improve adhesion.

The adhesive force between each side surface of the diaphragm 112 and the side surface protection part 122b may be smaller than the adhesive force between the electrode 111 in the base unit 110 and the diaphragm 112. That is, when the adhesive force between the side surface protection part 122b and the side surface of the diaphragm 112 is equal to or greater than the adhesive force between the electrode 111 and the diaphragm 112 in the base unit 110, the electrode 111 and the diaphragm 112 may be separated from each other when the side surface protection part 122b and the diaphragm 112 adhered to each other are separated from each other, thereby causing product defects. That is, when the finished electrode assembly is manufactured, the side surface protection part 122b may be removed from the separation part 122a of the separator 122 to improve electrolyte impregnation. Here, when the adhesive force between the side surface protection part 122b and the side surface of the diaphragm 112 is equal to or greater than the adhesive force between the electrode 111 and the diaphragm 112 in the base unit 110, the electrode 111 and the diaphragm 112 may also be separated in the base unit 110 to cause a defect.

Accordingly, the adhesive force between the side surface protection part 122b and the side surface of the diaphragm 112 may be smaller than the adhesive force between the electrode 111 and the diaphragm 112 in the base unit 110. Therefore, the side surface protection part 122b can be removed from the side surface of the diaphragm 112 without separating the electrode 111 and the diaphragm 112 in the base unit 110.

The auxiliary unit 120 having the above-described configuration may allow the battery capacity to be increased and also prevent foreign substances from entering into the side surfaces.

The separation sheet 122 of the auxiliary unit 120 and the base unit 110 may be adhered to each other with an adhesive force smaller than that between the electrode 111 and the diaphragm 112 in the base unit 110, or adjacent to each other without the adhesive force. That is, when the separation sheet 122 of the auxiliary unit 120 and the base unit 110, which are repeatedly stacked, are separated from each other, the electrodes and the separators disposed in the base unit 110 may be separated from each other due to the difference in adhesive force. For reference, the adhesion force may be expressed as a peel force. For example, the adhesive force between the electrode and the separator may be expressed as a force required to separate the electrode and the separator from each other. To prevent this, the separator 122 of the auxiliary unit 120 and the base unit 110 may be adhered to each other with an adhesive force smaller than that between the electrode 111 and the separator 112 or adjacent to each other without the adhesive force. Therefore, when the separation sheet 122 of the auxiliary unit 120 and the base unit 110 are separated from each other, it is possible to prevent the electrodes and the separators provided in the base unit from being separated from each other, thereby preventing the occurrence of defects in advance.

Fixing belt

A fixing band attached in a manner of surrounding the base unit 110 and the auxiliary unit 120 may be further provided.

That is, as shown in fig. 4, the fixing band 130 is attached to be connected with the separation sheet 122 of the auxiliary unit 120 and the bottom surface of the diaphragm 112 disposed at the lowermost end of the base unit 110. As a result, the engagement between the base unit 110 and the auxiliary unit 120 can be improved, and the attachment of the side surface protection part 122b of the partition 122 provided in the auxiliary unit 120 can also be improved.

The area of the side surface protection part 122b may be larger than that of the side surface of the base unit 110. Therefore, even if a meandering defect is generated in the side surface protecting part 122b, the side surface protecting part 122b can stably cover the side surface of the base unit 110.

A fine punched hole through which the electrolyte passes without passing foreign matter may be formed in the side surface protection portion 122b of the separator 122. The penetration of the electrolyte into the side surface of the electrode assembly 100, on which the side surface protection part 122b of the separator 122 is disposed, may be improved by punching, and thus, the impregnation of the electrolyte into the side surface of the electrode assembly 100 may be improved.

Therefore, the electrode assembly 100 according to the first embodiment of the present invention includes the auxiliary unit 120 provided with the separator 122. Therefore, it is possible to prevent foreign substances from entering into the side surfaces of the electrode assembly 100, thereby preventing the occurrence of defects in advance.

[ Secondary Battery according to second embodiment of the invention ]

As shown in fig. 5, the secondary battery 10 according to the second embodiment of the present invention includes an electrode assembly 100 and a case 200 accommodating the electrode assembly 100.

Here, the electrode assembly 100 includes: a base unit 110 having a structure in which a plurality of electrodes 111 and a plurality of separators 112 are alternately stacked and one electrode is stacked at the uppermost end; and an auxiliary unit 120 provided with a partition 122 provided at the uppermost side of the base unit 110.

Specifically, the separator 122 includes: a partition portion 122a provided on the uppermost end side of the base unit 110; and a side surface protecting portion 122b connected to each side surface of the partition 122a and folded to be in contact with the side of the base unit 110, thereby covering the side surface of the base unit 110.

The electrode assembly 100 has the same construction and function as the above-described electrode assembly according to the first embodiment of the present invention, and therefore, the same reference numerals are used and repeated description is omitted.

Therefore, the secondary battery 10 according to the second embodiment of the present invention includes the electrode assembly 100 provided with the separator 122. Accordingly, it is possible to prevent foreign substances from entering into the side surfaces of the electrode assembly 100 to prevent the occurrence of defects in advance, thereby improving the commerciality. In particular, the separator 122 may protect the side surface of the electrode assembly 100 to prevent the side surface of the electrode assembly 100 from being damaged.

[ method for manufacturing a secondary battery according to a second embodiment of the invention ]

As shown in fig. 6, a method for manufacturing a secondary battery according to a second embodiment of the present invention includes: (A) a basic unit manufacturing step, (B) an auxiliary unit manufacturing step, (C) an unfinished electrode assembly manufacturing step, (D) an unfinished electrode assembly pressing step, (E) a finished electrode assembly manufacturing step, and (F) a secondary battery manufacturing step.

(A) Basic cell manufacturing step

Referring to (a) in fig. 7, in (a) the base unit manufacturing step, a plurality of electrodes 111 and a plurality of separators 112 are alternately stacked to manufacture a base unit 110. Here, the basic unit 110 has a structure in which one electrode 111 is stacked on the uppermost end and one separator 112 is stacked on the lowermost end. Here, the plurality of electrodes may be a negative electrode and a positive electrode.

That is, the (a) basic cell manufacturing step has a structure in which four layers including a negative electrode as one electrode, a separator 112, a positive electrode as the other electrode, and the separator 112 are stacked once or repeatedly.

(B) Auxiliary unit manufacturing step

Referring to (B) of fig. 7, in the (B) auxiliary unit manufacturing step, the separation film 122A having a predetermined size is cut to manufacture the separation sheet 122 including a separation portion 122A having a size corresponding to the diaphragm 112 and a side surface protection portion 122B connected to each of both side surfaces of the separation portion 122A. Accordingly, the auxiliary unit 120 provided with the separation sheet 122 may be manufactured.

(C) Manufacturing step of unfinished electrode assembly

Referring to (d) and (C) of fig. 7, in the (C) unfinished electrode assembly manufacturing step, the partition 122a of the auxiliary unit 120 is disposed at the uppermost end side of the base unit 110. Next, after being folded along the boundary between the partition 122a and the side surface protection part 122b, the side surface protection part 122b is disposed in contact with the side surface of the base unit 110 to manufacture the unfinished electrode assembly 100A.

(D) Pressing step of unfinished electrode assembly

Referring to (e) of fig. 7, in the (D) unfinished electrode assembly pressing step, the uppermost end and the lowermost end of the unfinished electrode assembly 100A are pressed using the pressing device 30 to engage the base unit 110 and the auxiliary unit 120 provided in the unfinished electrode assembly 100A with each other.

Here, the base unit 110 and the auxiliary unit 120 are adhered to each other with an adhesive force smaller than that between the electrode 111 and the separator in the base unit 110.

Referring to (f), (D) of fig. 7, the pressing step of the unfinished electrode assembly further includes a process of bonding the side surface protection part 122b and the side surface of the separator 112 to each other. That is, when the pressing of the unfinished electrode assembly 100A is completed, the left and right ends of the unfinished electrode assembly 100A are pressed using the pressing device 30 to bond the side surface protection part 122b and the side surface of the separator 112, which are folded with respect to each other, to each other.

Here, the adhesive force between the side surface protection part 122b and the side surface of the diaphragm 112 is smaller than the adhesive force between the electrode 111 in the base unit 110 and the diaphragm 112.

(E) Manufacturing step of finished electrode assembly

Referring to (g) of fig. 7, in the manufacturing step of the finished electrode assembly, the fixing tape 130 is attached to surround the unfinished electrode assembly, thereby manufacturing the finished electrode assembly 100. That is, in the manufacturing step of the finished electrode assembly, one end of the fixing tape 130 is attached to the partition portion 122a of the separator 122 of the auxiliary unit 120, and the other end of the fixing tape 120 is attached to the bottom surface of the separator 122 disposed at the lowermost end of the base unit 110 via the side surface mounting portion 122b of the separator 122. Here, the fixing tape 130 is attached to both side surfaces of the unfinished electrode assembly.

(F) Secondary battery manufacturing step

Referring to (h) of fig. 7, in (F) the secondary battery manufacturing step, the finished electrode assembly 100 and an electrolyte (not shown) are accommodated in the case 200, and then, the edge surface of the case 200 is sealed to manufacture the finished secondary battery 10.

[ electrode group according to third embodiment of the present invention]

As shown in fig. 8, a battery pack 1 according to a third embodiment of the present invention includes one or more secondary batteries 10 and a pack case 20 accommodating the one or more secondary batteries 10. Each of the secondary batteries 10 includes an electrode assembly 100 and a case 200 accommodating the electrode assembly 100.

Also, the electrode assembly 100 includes: a base unit 110 having a structure in which a plurality of electrodes 111 and separators 112 are alternately stacked and one electrode 111 is stacked at the uppermost end; and an auxiliary unit provided with a partition 122, the partition 122 being provided at the uppermost side of the base unit 110. The partition plate 122 includes a partition portion 122a provided on the uppermost end side of the base unit 110; and a side surface protecting part 122b connected to each side surface of the partition part 122a and folded to be in contact with the side of the base unit 110, thereby covering the side of the base unit 110.

The secondary battery 10 has the same configuration and function as those of the above-described secondary battery according to the second embodiment of the present invention, and therefore, the same reference numerals are used for the same configuration, and the repetitive description is omitted.

Therefore, the battery pack 1 according to the third embodiment of the present invention includes the secondary battery 10 provided with the separator to significantly reduce the defect rate.

Electrode assembly according to fourth embodiment of the present invention]

As shown in fig. 9, the electrode assembly 100 according to the fourth embodiment of the present invention includes the auxiliary unit 120 provided with the separation sheet 122, the separation sheet 122 being disposed at the uppermost end side of the base unit 110.

Here, the separator 122 includes: a partition 122a provided on the uppermost side of the base unit 110; and a side surface protecting part 122b connected to each side surface of the partition part 122a and folded to be in contact with the side of the base unit 110, thereby covering the side of the base unit 110.

Specifically, the separator 122 is made of the same material as the diaphragm 112 provided in the base unit 110.

The auxiliary unit 120 may further include an electrode 121 disposed at an uppermost end side of the separator 122.

That is, the auxiliary unit 120 has a structure in which the electrodes 121 and the separators 122 are alternately stacked in the vertical direction. The auxiliary unit 120 in which the electrode 121 and the separator 122 are vertically stacked is stacked on the top surface side of the electrode 111 disposed on the uppermost end side of the base unit 110.

Here, the electrode 121 of the auxiliary unit 120 and the electrode 111 disposed at the uppermost end of the base unit 110 have different polarities. That is, when the electrode 111 disposed at the uppermost end of the basic unit 110 is the first electrode, the electrode 121 of the auxiliary unit 120 may be the second electrode. On the other hand, when the electrode 111 disposed at the uppermost end of the basic unit 110 is the second electrode, the electrode 121 of the auxiliary unit 120 may be the first electrode.

For example, the separator 122 includes: a partition 122a disposed on the uppermost end side of the base unit 110; and a side surface protecting part 122b connected to each side surface of the partition part 122a and folded to be in contact with the side of the base unit 110, thereby covering the side of the base unit 110. That is, in the separator 122, the partition 122a is disposed at the uppermost end side of the base unit 110 to separate the electrode 121 of the auxiliary unit 120 from the electrode 111 disposed at the uppermost end of the base unit 110, and the side surface protection part 122b is connected to each of both side surfaces of the partition 122 a. Here, the side surface protection part 122b is folded toward the side surface of the base unit 110 to prevent the side surface of the base unit 110 from being exposed to the outside. The side surface protection part 122b blocks the side surface of the base unit 110 from being exposed to the outside.

Therefore, the electrode assembly 100 according to the fourth embodiment of the present invention can block foreign materials from entering the side surface, and simultaneously secure a large battery capacity.

The electrode 121 has a structure in which an electrode active material layer is provided only on one surface facing the separator 122. That is, the electrode 121 includes an electrode collector 121a and an electrode active material layer 121b applied to an inner surface (a bottom surface of the electrode collector 121a when viewed in fig. 9) of the electrode collector 121a facing the separator 122.

Therefore, the electrode assembly 100 according to the fourth embodiment of the present invention can prevent unnecessary waste of the electrode active material layer, thereby significantly reducing costs.

Electrode assembly according to fifth embodiment of the present invention]

As shown in fig. 10 to 12, an electrode assembly 100 according to a fifth embodiment of the present invention includes a base unit 110 and an auxiliary unit 120. The auxiliary unit 120 includes a partition 122, and the partition 122 is disposed at the uppermost side of the base unit 110.

For example, the separator 122 includes: a partition portion 122a provided on the uppermost end side of the base unit 110; and a side surface protecting part 122b connected to each side surface of the partition part 122a and folded to be in contact with the side of the base unit 110, thereby covering the side of the base unit 110.

The partition plate 122 further includes a bottom surface protector 122c connected to the lower end surface of the side surface protector 122b and folded to contact the lowermost end surface of the base unit 110 to prevent foreign substances from entering between the lowermost end surface of the base unit 110 and the side surface protector 122b by the bottom surface protector 122 c.

Specifically, a part or the whole of the bottom surface guard 122c may be adhered to the lowermost end surface of the base unit 110. Accordingly, the fixing force of the separation sheet 122 may be increased to improve the adhesive force between the side surface protection part 122b and the diaphragm 112 of the base unit 110.

The partition sheet 122 further includes a surface protector 122d that is connected to each of two side surfaces (front and back surfaces of the side surface protector when viewed in fig. 10) of the side surface protector 122b and folded to be in contact with each of the front and back surfaces of the base unit 110, so as to effectively prevent foreign substances from entering the front and back surfaces of the base unit 110 by the surface protector 122 d.

In summary, referring to fig. 11, the separator 122 includes a partition 122a, a side surface protector 122b provided on each of both side surfaces of the partition 122a, a bottom surface protector 122c provided on each of both side surfaces of the side surface protector 122b, and a surface protector 122d provided on each of front and back surfaces of the side surface protector 122 b.

Therefore, the electrode assembly 100 according to the fifth embodiment of the present invention can prevent foreign substances from entering the front and back surfaces and the side surfaces of the electrode assembly.

Electrode assembly according to sixth embodiment of the present invention]

As shown in fig. 13, in the electrode assembly 100 according to the sixth embodiment of the present invention, the separator 122 includes a partition part 122a and a side surface protection part 122 b. When the manufacture of the electrode assembly is completed, the side surface protection part may be removed from the partition part 122 a. As a result, when manufacturing a secondary battery, the side surfaces of the electrode 100 may be opened to improve impregnation of the electrode assembly 100 and the electrolyte.

That is, since a large amount of foreign materials are generated when manufacturing the electrode assembly, the side surface of the electrode assembly 100 may be protected by the side surface protection part 122b of the separator 122, and when manufacturing of the electrode assembly 100 is completed, the side surface protection part 122b of the separator 122 may be removed to open the side surface of the electrode assembly 100.

As shown in fig. 13, a cutting line 122a may be formed on a boundary between the partition 122a and the side surface guard 122b, so that the side surface guard 122b may be easily cut along the cutting line 122 a.

Accordingly, the scope of the invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein. Variations that come within the meaning of equivalents of the claims and within the claims are to be regarded as being within the scope of the invention.