KR20170048932A - Rechargeable battery having gasket - Google Patents

Abstract

Provided is a secondary battery capable of reducing moisture permeation. The secondary battery according to one aspect of the present invention comprises: an electrode assembly including a first electrode, a separator, and a second electrode; a first outer member disposed opposite to an outer surface of one side of the electrode assembly; a second outer member disposed opposite to an outer surface of the other side of the electrode assembly; a gasket attached to the first outer member and the second outer member while covering a side end of the electrode assembly; and a moisture-proof layer formed on an outer surface of the gasket.

Description

[0001] RECHARGEABLE BATTERY HAVING GASKET [0002]

The present invention relates to a secondary battery having a gasket.

With the development of technology for mobile devices, the demand for secondary batteries is increasing as an energy source. A rechargeable battery is a battery which repeatedly performs charging and discharging unlike a primary battery.

A small secondary battery is used in portable electronic equipment such as a mobile phone, a notebook computer, and a camcorder, and a large secondary battery can be used as a motor driving power source for hybrid vehicles and electric vehicles.

For example, the pouch type secondary battery includes a stacked electrode assembly for charging and discharging, a pouch for accommodating the electrode assembly and the electrolyte, and an electrode tab for pulling out the electrode assembly to the outside of the pouch. The stacked electrode assembly is formed by repeatedly stacking unit stacked units composed of a negative electrode, a separator, a positive electrode and a separator, and is drawn out to the outside of the pouch by an electrode tab welded to the uncoated portion of the positive electrode.

The present invention provides a secondary battery capable of reducing moisture permeation.

A secondary battery according to an aspect of the present invention includes: an electrode assembly including a first electrode, a separator, and a second electrode; a first outer member disposed opposite to one outer surface of the electrode assembly; A second casing member, a gasket attached to the first casing member and the second casing member to surround the side of the electrode assembly, and a moisture-proof layer formed on the outer surface of the gasket.

Here, the moisture-proof layer may extend to the outer surface of the first exterior material, and the moisture-proof layer may extend to the outer surface of the second exterior material.

In addition, the moisture-proof layer may be made of a photocurable resin, and the secondary battery may further include an inner electrolyte layer formed on an inner surface of the gasket and having resistance to an electrolyte solution.

In addition, the electrode assembly may include an alignment groove, and the gasket may include an alignment guide that is partially coupled to the alignment groove.

The first electrode tab and the second electrode tab may further include a first electrode tab and a second electrode tab connected to the first electrode and the second electrode and spaced apart from the one end of the case and spaced apart from the first electrode tab, As shown in FIG.

The alignment grooves may include first grooves, second grooves, and third grooves formed in the first electrode, the second electrode, and the separator to be stacked, respectively, and corresponding to the alignment guide.

The gasket may include a first guide protruding in the lengthwise direction of the first electrode tab and a second guide spaced apart from the first guide and protruding from the side wall of the gasket.

Further, the first groove of the first electrode is formed so as to be parallel to the first guide, the first electrode includes a protruding unoccupied portion forming the first groove, and the protruded unoccupied portion includes the first And may be coupled between the guide and the second guide.

Further, the second groove of the second electrode may be formed corresponding to the first groove, the third groove of the separator is formed corresponding to the first groove of the first electrode, and the separator And a protruding support portion forming the third groove and supporting the protruding uncoated portion of the first electrode.

As described above, according to the embodiment of the present invention, a moisture-proof layer can be formed to reduce moisture penetration.

1 is a perspective view illustrating a secondary battery according to a first embodiment of the present invention.
2 is an exploded perspective view showing the secondary battery of FIG.
3 is an exploded perspective view showing an electrode assembly applied to FIG.
4 is a cross-sectional view taken along the line IV-IV in FIG.
5 is an exploded perspective view showing a gasket according to a second embodiment of the present invention.
6 is a cross-sectional view illustrating a secondary battery according to a second embodiment of the present invention.
7 is an exploded perspective view illustrating a secondary battery according to a third embodiment of the present invention.
8 is an exploded perspective view showing the electrode assembly applied to Fig.
9 is a partial plan view showing the alignment of the gasket and the electrode assembly of Fig. 7;
FIG. 10 is a sectional view cut in a state where the members shown in FIG. 7 are coupled.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

FIG. 1 is a perspective view illustrating a secondary battery according to a first embodiment of the present invention, and FIG. 2 is an exploded perspective view illustrating the secondary battery of FIG. 1. Referring to FIG.

1 and 2, the secondary battery 1 of the first embodiment includes an electrode assembly 110 for charging and discharging a current, a gasket 203 for covering a side end of the electrode assembly 110, A first outer casing member 201 and a second outer casing member 202 attached to the gasket, and a moisture-proof layer 31 formed on the outer surface of the gasket. The gasket 203, the first casing member 201, and the second casing member 202 constitute the casing 120.

The first casing member 201 is disposed on the outer surface of one side of the electrode assembly 110, and may be formed of a film. The second casing member 202 may be disposed on the other side of the electrode assembly and may be a film. For example, the first casing member 201 may be formed in a multi-layered sheet structure and may include an inner sheet 201a, an outer sheet 201b, and a metal sheet 201c.

The inner sheet 201a forms an inner surface of the case 120 and functions as an insulation and a heat seal, and may be formed of a polymer sheet. The outer sheet 201b forms an outer surface of the case 120 and acts as a protective member. The outer sheet 201b may be formed of a PET (polyethyleneterephthalate) sheet, a nylon sheet, or a PET-nylon composite sheet. The metal sheet 201c is provided between the inner and outer sheets 201a and 201b to provide the mechanical strength of the case 120. [ For example, the metal sheet 201c may be formed of an aluminum sheet. Also, the second casing member 202 may have a multi-layered sheet structure including an inner sheet, an outer sheet and a metal sheet in the same manner as the first casing member 201.

The gasket 203 is made of a polymer. Preferably, the secondary battery 1 may be made of a flexible polymer so that it can be easily bent. The gasket 203 is formed in a rectangular ring shape to wrap the side of the electrode assembly 110. The first casing member 201 is attached to one side of the gasket 203 and the second casing member 202 is attached to the other side of the gasket 203. The first casing member 201 and the second casing member 202 may be attached to the gasket 203 by thermal welding.

FIG. 3 is an exploded perspective view of the electrode assembly of FIG. 2, and FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 2 to 4, the electrode assembly 110 is formed by laminating a first electrode 11 (for example, an anode) and a second electrode 12 (for example, a cathode) with a separator 13 interposed therebetween And are stacked. The separator 13 may be formed of a polymer film that allows lithium ions to pass therethrough.

The electrode assembly 110 further includes a first electrode tab 14 and a second electrode tab 15 connected to the first and second electrodes 11 and 12, respectively. The first and second electrode tabs 14 and 15 are drawn out from one end of the case 120 and spaced apart from each other. However, the present invention is not limited thereto, and the electrode assembly 110 may have a structure in which the strip-shaped first electrode and the second electrode are wound with the separator interposed therebetween.

The first and second electrodes 11 and 12 through the separator 13 are connected to the first and second electrode tabs 14 and 15 to be fixed to the case 120 and form a free end on the opposite side. That is, when the electrode assembly 110 is bent, the first and second electrodes 11 and 12 and the separator 13 are slipped to the free ends on the sides of the first and second electrode tabs 14 and 15 It is possible to maintain the state.

The first electrode 11 includes a coating part 11a coated with an active material on a current collector of a thin metal plate and a non-coated part 11b set as an exposed part exposed without applying the active material. For example, the current collector of the first electrode 11 and the first electrode tab 14 may be formed of aluminum (Al).

The second electrode 12 includes a coating portion 12a coated with a current collector of a thin metal plate and an active material different from the active material of the first electrode 11 and an uncoated portion 12b set as an exposed current collector ). For example, the current collector of the second electrode 12 and the second electrode tab 15 may be formed of copper (Cu).

In the laminated state, the first and second electrodes 11 and 12 alternately arrange the non-coated portions 11b and 12b on both sides in the width direction (y-axis direction). 3, the non-printed portion 11b of the first electrode 11 is disposed on the right side and the non-printed portion 12b of the second electrode 12 is disposed on the left side.

1 and 2, the first electrode tab 14 is connected to the non-coated portion 11b of the first electrode 11 and the second electrode tab 15 is connected to the non-printed portion 11b of the second electrode 12, And is connected to the part 12b. Therefore, the first and second electrode tabs 14 and 15 are spaced apart from each other at one side of the case 120. The first and second electrode tabs 14 and 15 may be welded to the non-coated portions 11b and 12b.

The gasket 203 may have fixing grooves 141 and 151 for fixing the first and second electrode tabs 14 and 15. The first and second electrode tabs 14 and 15 are covered with insulating members 16 and 17 to be fixed to the fixing grooves 141 and 151 and are pulled out of the case 120 through the fused portion.

As shown in FIG. 4, a moisture-proof layer 31 is formed on the outer surface of the gasket 203. The moisture-proof layer 31 may be formed by coating a photo-curable material. The moisture-proof layer 31 is made of a material having water resistance, and may include a polyester-based, epoxy-based, urethane-based, polyether-based or polyacrylic resin.

The moisture-proof layer 31 may extend from the outer surface of the first casing member 201 to the outer surface of the second casing member 202. The moisture-proof layer 31 may include a first portion 31a contacting the gasket 203, A second portion 31b that extends from the first portion 31a to abut the first enclosure 201 and a third portion 31c that continues from the first portion 31a and abuts the second enclosure 202 .

If the outer surface of the gasket 203 is covered with the moisture-proof layer 31, moisture can be prevented from penetrating into the interior of the secondary battery 1 through the gasket 203. In addition, since the moisture-proof layer 31 is formed to extend to the first casing member 201 and the second casing member 202, not only the bonding force between the gasket 203 and the first casing member 201 and the second casing member 202 can be improved It is possible to prevent moisture from penetrating into the gap between the gasket 203 and the first casing member 201 and into the gap between the gasket 203 and the second casing member 202. [

Hereinafter, a secondary battery according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG.

FIG. 5 is an exploded perspective view illustrating a gasket according to a second embodiment of the present invention, and FIG. 6 is a cross-sectional view illustrating a secondary battery according to a second embodiment of the present invention.

5 and 6, the secondary battery 2 according to the second embodiment has the structure of the moisture-proof layer 32 and the structure of the secondary battery according to the first embodiment described above except that the electrolyte- The same structure as that of the battery is provided, and a duplicate description thereof will be omitted.

The secondary battery 2 according to the second embodiment includes a case 130 surrounding the electrode assembly 110 and the electrode assembly 110. The case 130 includes a first casing member 201, 202, and a gasket 204.

The gasket 204 is made of a material having elasticity so as to be bent in a rectangular annular shape. The gasket 204 may include fixing grooves 152 and 142 into which the first and second electrode tabs 14 and 15 are inserted.

A moisture-proof layer 32 may be formed on the outer surface of the gasket 204 and a moisture-proof layer 32 may be formed along the outer surface of the gasket 204. In the second embodiment, the moisture-proof layer 32 may be formed only on the gasket 204. [ The moisture-proof layer 32 may be formed of a coating or a film. The moisture-proof layer 32 may be made of a photo-curable material. The photo-curable material may be coated on the gasket 204 and then cured by irradiating light to form the moisture-proof layer 32.

On the other hand, the inner electrolyte layer 34 is formed on the inner surface of the gasket 204. The inner electrolyte layer 34 may be made of a material having low reactivity with the electrolyte solution. The electrolyte layer 34 may be formed by coating a material containing a fluororesin. In addition, the electrolyte layer 34 may include polytetrafluoroethylene or ethylene tetrafluoroethylene. The electrolyte layer 34 may be coated directly on the surface of the gasket 204 and attached to the inner surface of the gasket 204 via the adhesive layer.

When the inner electrolyte layer 34 is formed on the inner surface of the gasket 204 as in the second embodiment, the gasket 204 having elasticity is used, and the gasket 204 does not react with the electrolyte solution, so that a stable structure can be maintained.

Hereinafter, a secondary battery according to a third embodiment of the present invention will be described.

FIG. 7 is an exploded perspective view illustrating a secondary battery according to a third embodiment of the present invention, and FIG. 8 is an exploded perspective view illustrating the electrode assembly of FIG.

7 and 8, the secondary battery 3 according to the third embodiment includes the secondary battery 3 according to the first embodiment, except for the structure of the gasket 205 and the electrode assembly 310. [ The description of the same configuration will not be repeated.

The secondary battery 3 according to the third embodiment includes an electrode assembly 310 and a case 140. The case 140 includes a first casing member 201, a second casing member 202, and a gasket 205 ).

The electrode assembly 310 is stacked by stacking a first electrode 41 (for example, an anode) and a second electrode 42 (for example, a cathode) with a separator 43 interposed therebetween. The separator 43 may be formed of a porous polymer film that allows lithium ions to pass therethrough.

The electrode assembly 310 further includes a first electrode tab 44 and a second electrode tab 45 connected to the first and second electrodes 41 and 42, respectively. The first and second electrode tabs 44 and 45 are drawn out from one end of the case 140 and spaced apart from each other at an interval.

The first and second electrodes 41 and 42 with the separator 43 interposed therebetween are connected to the first and second electrode tabs 44 and 45 to be fixed to the case 140 and form a free end on the opposite side. That is, when the electrode assembly 310 is bent, the first and second electrodes 41 and 42 and the separator 43 are slipped to the free ends on the sides of the first and second electrode tabs 44 and 45 It is possible to maintain the state.

The first electrode 41 includes a coating portion 41a coated with an active material on a current collector of a thin metal plate and an uncoated portion 41b set as an exposed object without applying the active material. The second electrode 42 includes a coating portion 42a formed by coating a current collector made of a thin metal plate and an active material different from the active material of the first electrode 41 and an uncoated portion 42b set as an exposed current collector ).

In the laminated state, the first and second electrodes 41 and 42 alternately arrange the non-printed portions 41b and 42b on both sides in the width direction (y-axis direction). The non-printed portion 41b of the first electrode 41 is disposed on the right side and the non-printed portion 42b of the second electrode 42 is disposed on the left side.

The first electrode tab 44 is connected to the non-printed portion 41b of the first electrode 41 and the second electrode tab 45 is connected to the non-printed portion 42b of the second electrode 42. Therefore, the first and second electrode tabs 44 and 45 are spaced apart from each other at one side of the case 140. The first and second electrode tabs 44 and 45 may be welded to the non-coated portions 41b and 42b.

The gasket 205 may include fixing grooves 143 and 153 for fixing the first and second electrode tabs 44 and 45. The first and second electrode tabs 44 and 45 are covered with insulating members 46 and 47 to be fixed to the fixing grooves 143 and 153 and are drawn out of the case 140 through the fused portions.

The electrode assembly 310 has an aline groove G on one side and the case 140 has an aligning guide 51 protruding toward the aligning groove G so as to be partially engaged with the aligning groove G, .

FIG. 9 is a partial plan view showing an alignment state of the gasket and the electrode assembly of FIG. 7, and FIG. 10 is a sectional view cut in a state where the members shown in FIG. 7 are coupled.

Referring to FIGS. 7 and 10, the gasket 205 is formed in the shape of a square ring to wrap the side of the electrode assembly 310. The first casing member 201 is attached to one side of the gasket 205 and the second casing member 202 is attached to the other side of the gasket 205.

A moisture-proof layer 35 is formed on the outer surface of the gasket 205. The moisture-proof layer 35 may be formed by coating a photo-curable material. The moisture-proof layer 35 may extend to the outer surface of the first casing member 201 and the outer surface of the second casing member 202.

7, an alignment guide 51 is formed in the gasket 205, and the alignment guide includes a first guide 511 and a second guide 512 formed on one side of the gasket 205 do. The first guide 511 is inserted into the alignment groove G which is linearly protruded from the gasket 205 in the direction of change of the length of the electrode assembly 310 in the x axis direction and formed in a straight line, The primary position of the electrode assembly 310 is set. The first guide 511 protrudes from the gasket 205 in the direction toward the first electrode tab 44 at the opposite end of the end where the first electrode tab 44 is provided and the longitudinal direction of the first guide 511 And may be parallel to the longitudinal direction of the one-electrode tab 44.

The second guide 512 may protrude from the side wall of the gasket 205 so as to be spaced apart from the first guide 511. When the first guide 511 is inserted into the alignment groove G, the second guide 512 supports the side edge of the electrode assembly 310 forming the alignment groove G, The outermost position of the side end of the electrode assembly 310 is set.

The electrode assembly 310 maintains the interval C2 (in the y-axis direction) between the inner side wall of the case 140 and the second guide 512 in the case 140 by the second guide 512, The electrode assembly 310 is smoothly slipped in the case 140 when the electrode assembly 310 is bent.

8 and 9, the alignment groove G includes a first groove G1 and a second groove G2 formed in the first and second electrodes 41 and 42 and the separator 43, respectively, And a third groove G3. The first, second and third grooves (G1, G2, G3) are partly joined corresponding to the alignment guide (51).

The first groove (G1) of the first electrode (41) is formed to be parallel to the first guide (511). The first electrode 41 is formed with a protruded unoccupied portion 41c which is separated from the coated portion 41a while forming a first groove G1. The protruding uncoated portion 41c is coupled between the first guide 511 and the second guide 512. [ The first groove G1 is guided by the first guide 511 and the protrusion uncovered portion 41c is guided by the first and second guides 511 and 512 do.

The second groove G2 of the second electrode 42 is formed corresponding to the first groove G1 and the protruded uncoated portion 41c of the first electrode 41. [ The second electrode 42 is formed larger than the first electrode 41 and the first groove G1 of the first electrode 41 is formed larger than the second groove G2 of the second electrode 42 The entire area of the coating portion 41a of the first electrode 41 may correspond to the coating portion 42a of the second electrode 42. [ Therefore, the capacity performance of the secondary battery 3 can be determined by the size of the first electrode 41.

The third groove (G3) of the separator (43) is formed corresponding to the first groove (G1) of the first electrode (41). The separator 43 is formed with a protruding support portion 43c for forming a third groove G3 while the protruding support portion 43c supports the protruding uncooled portion 41c of the first electrode 41, 511 and the second guide 512. [ The third groove G3 is guided by the first guide 511 and the projecting support portion 43c is guided between the first and second guides 511 and 512 when the length of the electrode assembly 310 changes .

The third groove G3 is formed to be smaller than the first and second grooves G1 and G2 at the portion where the first and second grooves G1 and G2 face each other. That is, since the separator 43 is formed to be larger than the first and second electrodes 41 and 42, the first and second electrodes 41 and 42 can be electrically isolated. 9, the width (y-axis direction) of the separator 43 is equal to the width of the second electrode 42, and the length (x-axis direction) of the third groove G3 is longer than the length of the second groove G2 It is smaller.

An end of the electrode assembly 310 where the alignment groove G is formed is spaced apart from the gasket 205 and a margin C3 is formed between the electrode assembly 310 and the inner surface of the gasket 205. The margin portion C3 accommodates a change in length of the electrode assembly 310 when the electrode assembly 310 is bent.

The length of the electrode assembly 310 increases in the case 140 as the case 140 and the electrode assembly 310 are bent while the bending stress acts on the secondary battery 3, Respectively.

At this time, the first and second electrodes 41 and 42 and the separator 43 are slipped as the length increases, and the first, second and third grooves G1, G2 and G3 are formed by the first guide 511 Slip guidance. Therefore, even when the electrode assembly 310 is bent, the first and second electrodes 41 and 42 and the separator 43 can maintain the alignment state. The first and second electrodes 41 and 42 and the separator 43 are in a more stable state because the protruding uncoated portion 41c and the protruding support portion 43c are guided by the second guide 512 And can be guided while maintaining.

The electrode assembly 310 and the secondary battery 3 can be bent to a degree corresponding to the bending stress as the length is increased by the action of the bending stress and the increased length is accommodated and aligned in the margin portion C3. Therefore, when the secondary battery 3 is bent, no breakage occurs in the secondary battery 3 and an internal short-circuit is not generated.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

1, 2, 3: secondary battery 110, 310: electrode assembly
11: first electrode 12: second electrode
11a, 41a: Coating portion 11b, 41b:
12a, 42b: Coating portion 12b, 42b:
13, 43: separator 14, 44: first electrode tab
15, 45: second electrode tabs 16, 17, 46, 47: insulating member
41c: protruding and non-projecting portion 43c:
120, 130, 140: case 141, 142, 143, 151, 152, 153:
201: First exterior material 201a: Inner sheet
201b: outer sheet 201c: metal sheet
202: second outer casing 203, 204, 205:
31, 32, 35: a moisture-proof layer 31a: a first portion
31b: second part 31c: third part
34: inner electrolyte layer 51: alignment guide
511: first guide 512: second guide
G: Aligned home G1: First home
G2: second groove G3: third groove

Claims (12)

An electrode assembly including a first electrode, a separator, and a second electrode;
A first casing facing the one outer surface of the electrode assembly;
A second outer casing disposed opposite to the other outer surface of the electrode assembly;
A gasket attached to the first casing and the second casing while covering a side end of the electrode assembly; And
A moisture-proof layer formed on an outer surface of the gasket;
And a secondary battery. The method according to claim 1,
Wherein the moisture-proof layer extends to an outer surface of the first casing member. 3. The method of claim 2,
And the moisture-proof layer extends to an outer surface of the second casing. The method according to claim 1,
Wherein the moisture-proof layer is made of a photocurable resin. The method according to claim 1,
And an inner electrolyte layer formed on an inner surface of the gasket and having resistance to an electrolytic solution. The method according to claim 1,
Wherein the electrode assembly includes an alignment groove,
And the gasket includes an aline guide partially coupled to the alignment groove. The method according to claim 6,
Further comprising a first electrode tab and a second electrode tab connected to the first electrode and the second electrode and spaced apart from the first electrode tab at one end of the case,
And the alignment groove is formed in the longitudinal direction of the first electrode tab. 8. The method of claim 7,
Wherein the alignment grooves are respectively formed in the first electrode, the second electrode and the separator to be laminated, and the first groove, the second groove and the third groove corresponding to the alignment guide. 9. The method of claim 8,
The alignment guide
A first guide protruding from the gasket in the longitudinal direction of the first electrode tab,
And a second guide spaced apart from the first guide and protruding from a side wall of the gasket. 10. The method of claim 9,
Wherein the first groove of the first electrode comprises:
The first guide being formed in parallel with the first guide,
Wherein the first electrode includes a protruding uncoated portion forming the first groove, and the protruded uncoated portion is coupled between the first guide and the second guide. 11. The method of claim 10,
And the second groove of the second electrode is formed corresponding to the first groove. 12. The method of claim 11,
Wherein the third groove of the separator is formed in correspondence with the first groove of the first electrode and the separator forms the third groove and has a protruding support portion for supporting the protruding solid portion of the first electrode, .

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