Patent Description:
The present invention relates to a method for manufacturing a secondary battery. Also, the disclosure relates to a secondary battery and a pressing block for manufacturing the secondary battery.

Rechargeable batteries are rechargeable unlike primarily batteries, and also, the possibility of compact size and high capacity is high. Thus, recently, many studies on rechargeable batteries are being carried out. As technology development and demands for mobile devices increase, the demands for rechargeable batteries as energy sources are rapidly increasing.

Rechargeable batteries are classified into coin type batteries, cylindrical type batteries, prismatic type batteries, and pouch type batteries according to a shape of a battery case. In such a secondary battery, an electrode assembly mounted in a battery case is a chargeable and dischargeable power generating device having a structure in which an electrode and a separator are stacked.

The electrode assembly may be approximately classified into a jelly-roll type electrode assembly in which a separator is interposed between a positive electrode and a negative electrode, each of which is provided as the form of a sheet coated with an active material, and then, the positive electrode, the separator, and the negative electrode are wound, a stacked type electrode assembly in which a plurality of positive and negative electrodes with a separator therebetween are sequentially stacked, and a stack/folding type electrode assembly in which stacked type unit cells are wound together with a separation film having a long length.

Recently, the pouch-type battery in which a stack/ folding type electrode assembly is built in a pouch-type battery case provided as an aluminum lamination sheet is attracting much attention due to its low manufacturing cost, small weight, easy shape deformation, and the like, and thus, its usage is gradually increasing.

<FIG> is a perspective view of a secondary battery according to a related art.

Referring to <FIG>, there has been a problem in that a wrinkle <NUM> is generated on an outer shell <NUM> of a battery case <NUM> and in the vicinity of the outer shell <NUM> while a secondary battery according to the related art is manufactured.

In more detail, there has been a problem in that a wrinkle <NUM> having a bat-ear shape is generated on the outer shell <NUM> of the battery case <NUM> and in the vicinity of the outer shell <NUM> while vacuum is applied to discharge an internal gas of the battery case <NUM> to the outside.

Also, there has been a problem in that interference occurs between the stacked secondary battery <NUM> when a plurality of secondary batteries <NUM> are stacked to be modularized because the wrinkle <NUM> is generated on the battery case <NUM>. Additionally, <CIT> relates to battery case having anti-wrinkle pattern. <CIT> relates to a pouch type secondary battery aimed at preventing the loss of electrolyte or the permeation of moisture. <CIT> relates to a method of manufacturing a secondary battery including sealing a side portion of the first case and a side portion of the second case using a jig.

One aspect of the present invention is to provide a secondary battery, which is capable of preventing a wrinkle from being generated on an outer shell of a battery case in the secondary battery, and a method for manufacturing the same, and a pressing block for manufacturing the secondary battery.

In a secondary battery and a method for manufacturing the secondary battery according to an embodiment of the present invention, the method for manufacturing the secondary battery as defined in claim <NUM> comprises: a forming step of forming a pouch sheet to form an accommodation part in which an electrode assembly is accommodated, a folding step of folding the pouch sheet with respect to a folding part so that the electrode assembly is accommodated in the accommodation part, and the accommodation part is blocked from the outside to form a battery case, and an anti-wrinkle step of forming an anti-wrinkle bending part on an outer shell to prevent wrinkles from being generated on the outer shell of the folded pouch sheet.

Also, a secondary battery is disclosed. It comprises: an electrode assembly in which electrodes and separators are alternately combined and stacked on each other and a battery case formed by folding a pouch sheet to accommodate an electrode assembly, wherein an anti-wrinkle bending part is formed on an outer shell to prevent wrinkles from being generated on the outer shell of the battery case.

Furthermore, a pressing block for a secondary battery is disclosed. It comprises a plurality of pressing blocks moving in a direction facing each other to press and compress an outer shell of a pouch sheet in which an electrode assembly is accommodated and a bending formation part formed on each of pressing surfaces of the plurality of pressing blocks so that an anti-wrinkle bending part is formed on the outer shell when the outer shell of the pouch sheet is pressed by the plurality of pressing blocks.

According to the present invention, the anti-wrinkle bending part may be formed on the outer shell of the battery case in the secondary battery to prevent the wrinkle from being generated on the outer shell. Particularly, when the vacuum is applied to discharge the internal gas of the battery case to the outside, the wrinkle having the bat-ear shape may be prevented from being generated on the outer shell of the battery case and in the vicinity of the outer shell. Here, the anti-wrinkle bending part may be disposed on the opposite side of the gas pocket part, through which the internal gas is discharged, in the outer shell of the battery case to support the opposite side of the gas pocket part when the vacuum is applied, thereby effectively preventing the wrinkle from being generated on the opposite side of the gas pocket part and the vicinity of the opposite side.

The objectives, specific advantages, and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. It should be noted that the reference numerals are added to the components of the drawings in the present specification with the same numerals as possible, even if they are illustrated in other drawings. Also, the present invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In the following description of the present invention, the detailed descriptions of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

<FIG> is a flowchart illustrating a method for manufacturing a secondary battery according to an embodiment of the present invention, and <FIG> is a plan view illustrating a forming step in the method for manufacturing the secondary battery according to a first embodiment of the present invention.

Referring to <FIG> and <FIG>, a method for manufacturing a secondary battery <NUM> according to a first embodiment of the present invention comprises a forming step (S10) of forming a pouch sheet <NUM>, a folding step (S20) of folding the pouch sheet <NUM>, and an anti-wrinkle step (S30) of forming an anti-wrinkle bending part <NUM> on an outer shell <NUM> of the pouch sheet <NUM>. Also, the method for manufacturing the secondary battery according to the first embodiment of the present invention may further comprise a sealing step of sealing the outer shell <NUM> of the pouch sheet <NUM> after the folding step (S20) (see <FIG>).

<FIG> is a cross-sectional view taken along line A-A' of <FIG>.

Hereinafter, the method for manufacturing the secondary battery according to the first embodiment of the present invention will be described in more detail with reference to <FIG>.

Referring to <FIG>, in the forming step (S10), the pouch sheet <NUM> is formed to form an accommodation part <NUM> in which an electrode assembly <NUM> is accommodated. Here, the accommodation part <NUM> may comprise a first accommodation part <NUM> and a second accommodation part <NUM>.

Also, in the forming step (S10), the first accommodation part <NUM> and the second accommodation part <NUM> may be formed symmetrically on both sides with respect to the folding part <NUM> of the pouch sheet <NUM>.

Furthermore, in the forming step (S10), one surface of the pouch sheet <NUM> may be pressed to form a groove having an opened top surface, thereby forming the accommodation part <NUM>.

The electrode assembly <NUM> may be a chargeable and dischargeable power generation element and have a structure in which electrodes (not shown) and separators (not shown) are combined and alternately stacked.

The electrodes may comprise a positive electrode and a negative electrode. Also, each of the separators separates the positive electrode from the negative electrode to electrically insulate the positive electrode from the negative electrode.

The positive electrode may comprise a positive electrode collector (not shown) and a positive electrode active material (not shown) applied to the positive electrode collector, and the negative electrode may comprise a negative electrode collector (not shown) and a negative electrode active material (not shown) applied to the negative electrode collector.

For example, the positive electrode collector may be provided as foil made of an aluminum (Al) material.

The positive electrode active material may comprise, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound containing at least one of these and mixtures thereof.

For example, the negative electrode collector may be provided as foil made of a copper (Cu) or nickel (Ni) material.

The negative electrode active material may comprise synthetic graphite, lithium a metal, a lithium alloy, carbon, petroleum coke, activated carbon, graphite, a silicon compound, a tin compound, a titanium compound, or an alloy thereof.

The separator is alternately stacked with the positive electrode and the negative electrode, which are made of insulation materials. Here, the separator may be disposed between the positive electrode and the negative electrode and outer surfaces of the positive electrode and the negative electrode. Also, the separator may be provided as, for example, a polyolefin-based resin film such as polyethylene or polypropylene having micropores.

One side of an electrode tab <NUM> is provided on the electrode and then electrically connected to the electrode. Here, the electrode tab <NUM> may comprise a positive electrode tab and a negative electrode tab. The positive electrode tab may be electrically connected to the positive electrode, and the negative electrode tab may be electrically connected to the negative electrode.

<FIG> is a plan view illustrating the folding step (S20) in the method for manufacturing the secondary battery according to the first embodiment of the present invention.

Referring to <FIG>, <FIG>, and <FIG>, in the folding step (S20), the electrode assembly <NUM> may be accommodated in the accommodation part <NUM> of the pouch sheet <NUM>, and then, the pouch sheet <NUM> may be folded to form the battery case <NUM>.

Here, in the folding step (S20), the pouch sheet <NUM> may be folded with respect to a folding part <NUM> of the pouch sheet <NUM> so that the accommodation part <NUM> of the pouch sheet <NUM> is blocked from the outside.

Also, in the folding step (S20), a bending part for folding may be formed along a virtual line of the folding part <NUM>, and the pouch sheet <NUM> may be bent to be folded along the bending part for the folding.

Furthermore, in the folding step (S20), the first accommodation part <NUM> and the accommodation part <NUM> in the pouch sheet <NUM> may be folded to face each other. The battery case <NUM> is formed to comprise the accommodation part <NUM> and a gas pocket part <NUM> having a passage extending from the accommodation part <NUM> through the forming step (S10) and the folding step (S20).

<FIG> is a plan view illustrating a sealing step and an anti-wrinkle step in the method for manufacturing the secondary battery according to an embodiment of the present invention.

Referring to <FIG> and <FIG>, in the sealing step (S20), the outer shell of the pouch sheet <NUM> may be sealed so that a portion of the accommodation part <NUM> except for a direction of the gas pocket part <NUM> after the folding step (S20) to form the battery case <NUM>.

Here, in the sealing step, the outer shell of the pouch sheet <NUM> may be thermally fused to form a first sealing part <NUM> and a second sealing part <NUM>. Here, according to the invention, the folding part <NUM> is formed at a first side 110a, the gas pocket part <NUM> is formed at a fourth side 110d that is opposite to the folding part <NUM>, the first sealing part <NUM> is formed at a second side 110b, and the second sealing part <NUM> is formed at a third side 110c in four directions on the outer shell of the battery case <NUM>.

The sealing step may be performed before an anti-wrinkle step (S30) after the folding step (S20).

Furthermore, for another example, the sealing step may be performed together with the anti-wrinkle step (S30) after the folding step (S20).

<FIG> is a plan view illustrating the sealing step and the anti-wrinkle step in the method for manufacturing the secondary battery according to the first embodiment of the present invention, and <FIG> is a side view illustrating the anti-wrinkle step in the method for manufacturing the secondary battery according to the first embodiment of the present invention.

Referring to <FIG>, <FIG>, and <FIG>, in the anti-wrinkle step (S30), the outer shall of the pouch sheet <NUM> may be thermally pressed to form an anti-wrinkle bending part <NUM>.

Here, the outer shell may be thermally pressed to form the anti-wrinkle bending part <NUM>.

Also, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent to have a plurality of bent portions. Here, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent in a zigzag shape.

Also, in the anti-wrinkle step (S30), for example, the anti-wrinkle bending part <NUM> may be bent in a bent shape. Here, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent to have a first bent part 115a and a second bent part 115b. Here, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be formed to have an "N"-shaped cross-section.

Furthermore, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be formed so that the bent portion is vertically formed with respect to the outer shell that is horizontally formed on one side surface of the battery case <NUM>.

In the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> is formed at a folding part-side of each of the first sealing part <NUM> and the second sealing part <NUM> on the outer shell of the battery case <NUM>. That is, the anti-wrinkle bending part <NUM> is formed at a portion of each of the first sealing part <NUM> and the second sealing part <NUM>, which is in the vicinity of the folding part <NUM>. Here, in the anti-wrinkle step (S30), for example, the anti-wrinkle bending part <NUM> may be formed to have length of <NUM>% to <NUM>% of a length of each of the first sealing part <NUM> and the second sealing part <NUM>. The anti-wrinkle bending part <NUM> may be formed to have a length equal to or greater than <NUM>% of the length of each of the first sealing part <NUM> and the second sealing part <NUM> to effectively realize the anti-wrinkle effect at the first sealing part <NUM> and the second sealing part <NUM>. The anti-wrinkle bending part <NUM> may be formed to have a length equal to or less than <NUM>% of each of the length of each of the first sealing part <NUM> and the second sealing part <NUM> to improve workability. Here, in the anti-wrinkle step (S30), for example, the anti-wrinkle bending part <NUM> may be formed to have a length corresponding to <NUM>% of the length of each of the first sealing part <NUM> and the second sealing part <NUM>. Here, in the anti-wrinkle step (S30), when the anti-wrinkle bending part <NUM> is bent, a bending line may be formed from the first sealing part <NUM> and the second sealing part <NUM> toward the gas pocket part <NUM>. That is, in the anti-wrinkle step (S30), a bending line may be formed in a parallel to a gas discharge direction G on the gas pocket part <NUM>.

Also, in the anti-wrinkle step (S30), for another example, the anti-wrinkle bending part <NUM> may be formed over the entire first and second sealing parts <NUM> and <NUM> on the outer shell of the battery case <NUM>.

Furthermore, in the anti-wrinkle step (S30), for another example, the anti-wrinkle bending part <NUM> may be formed at the folding part <NUM> on the outer shell of the battery case <NUM>.

Also, in the anti-wrinkle step (S30), for another example, the anti-wrinkle bending part <NUM> may be formed at the first sealing part <NUM>, the second sealing part <NUM>, and the folding part <NUM> on the outer shell of the battery case <NUM>.

In the anti-wrinkle step (S30), a shape retaining part <NUM> may be further formed on an outer surface of the anti-wrinkle bending part <NUM> to retain a shape of the anti-wrinkle bending part <NUM>. Here, the shape retaining part <NUM> may prevent the anti-wrinkle bending part <NUM> from being deformed and also prevent the anti-wrinkle effect of the pouch sheet <NUM> from being deteriorated due to the deformation of the anti-wrinkle bending part <NUM>. Here, in the anti-wrinkle step (S30), the shape retaining part <NUM> may be applied to the outer surface of the anti-wrinkle bending part <NUM>.

Also, the shape retaining part <NUM> may be made of an insulating material and a heat-resistance material. Here, the shape retaining part <NUM> may be made of, for example, silicone. Thus, the shape retaining part <NUM> may retain the shape of the anti-wrinkle bending part <NUM> without being damaged by heat having a high temperature.

<FIG> is a plan view illustrating the sealing step in the method for manufacturing the secondary battery according to the first embodiment of the present invention.

Referring to <FIG>, <FIG>, and <FIG>, in the sealing step, the cut portion of the gas pocket part may be sealed to seal the accommodation part <NUM> after the anti-wrinkle step (S30).

Here, in the sealing step, the cut portion of the gas pocket part <NUM> may be thermally fused to form a third sealing part <NUM>, thereby safely sealing the battery case <NUM>.

Thus, referring to <FIG>, <FIG>, and <FIG>, in the method for manufacturing the secondary battery according to the first embodiment of the present invention, the anti-wrinkle bending part <NUM> may be formed on the outer shell of the battery case <NUM> of the secondary battery through the anti-wrinkle step (S30) to prevent the wrinkles from being generated over the outer shell and the vicinity of the outer shell. Particularly, when the vacuum is applied to discharge the internal gas of the battery case <NUM> to the outside, the wrinkle having the bat-ear shape may be prevented from being generated on the outer shell of the battery case <NUM> and in the vicinity of the outer shell. Here, the anti-wrinkle bending part <NUM> may be disposed at the opposite side of the gas pocket part <NUM>, through which the internal gas is discharged, on the outer shell of the battery case <NUM>. Thus, when the vacuum is applied, the anti-wrinkle bending part <NUM> may support the opposite side of the gas pocket part <NUM> and effectively prevent the wrinkles from being generated on the folding part <NUM> that is the opposite side of the gas pocket part <NUM> and the surrounding portion of the folding part-side on the first and second sealing parts <NUM> and <NUM>, which are in the vicinity of the folding part <NUM>. Also, after the secondary battery <NUM> is manufactured, even when a gas generated during the use (charging and discharging) is discharged, the wrinkles of the battery case <NUM> and the occurrence of the wrinkle may be significantly reduced.

Here, the process of discharging the internal gas of the battery case <NUM> may be, for example, performed for discharging the internal gas generated while the charging/discharging of the secondary battery to activate the secondary battery in the process of manufacturing the secondary battery or performed for discharging the internal gas generated while the charging/discharging of the secondary battery during the use of the secondary battery.

Also, the anti-wrinkle bending part <NUM> may be formed on the outer shell of the battery case <NUM>, and the shape retaining part <NUM> may be applied to the outer surface of the anti-wrinkle bending part <NUM> to more effectively prevent the anti-wrinkle bending part <NUM> from being deformed. Thus, the occurrence of the wrinkles on the outer shell and the portion of the battery case <NUM>, which is in the vicinity of the outer shell, may be prevented, and the deformation of the outer appearance of the battery case <NUM> and the occurrence of cracks in the battery case <NUM> due to the occurrence of the wrinkles may be prevented.

<FIG> is a side view illustrating an anti-wrinkle step in a method for manufacturing a secondary battery according to a second embodiment of the present invention.

Referring to <FIG> and <FIG>, a method for manufacturing a secondary battery <NUM> according to a second embodiment of the present invention comprises a forming step (S10) of forming a pouch sheet <NUM>, a folding step (S20) of folding the pouch sheet <NUM>, and an anti-wrinkle step (S30) of forming an anti-wrinkle bending part <NUM> on an outer shell of the pouch sheet <NUM>. Also, the method for manufacturing the secondary battery according to the second embodiment of the present invention may further comprise a sealing step of sealing an outer circumferential surface of the pouch sheet <NUM> after the folding step (S20).

The method for manufacturing the secondary battery according to the second embodiment of the present invention is the same as the method for manufacturing the secondary battery according to the first embodiment of the present invention except for an anti-wrinkle bending part <NUM> formed through an anti-wrinkle step (S30).

Thus, contents of this embodiment, which are duplicated with those according to the first embodiment, will be briefly described, and also, differences therebetween will be mainly described. In detail, in the method for manufacturing the secondary battery according to the second embodiment of the present invention, in the anti-wrinkle step (S30), a first sealing part <NUM> and a second sealing part of a pouch sheet <NUM> may be thermally compressed to form an anti-wrinkle bending part <NUM>.

Also, in the anti-wrinkle step (S30), for example, the anti-wrinkle bending part <NUM> may be bent in a bent shape. Here, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent to have a first bent part 215a, a second bent part 215b, and a third bent part 215c. Here, for example, the anti-wrinkle bending part <NUM> may be formed to have an "W"-shaped cross-section.

In the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be formed so that the bent portion is vertically formed with respect to the first sealing part <NUM> and the second sealing part, which are horizontally formed on one side of the battery case <NUM>. Here, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be formed at a folding part-side of each of the first sealing part <NUM> and the second sealing part, which are adjacent to the folding part.

Also, the shape retaining part <NUM> may be made of an insulating material and a heat-resistance material. Here, the shape retaining part <NUM> may be made of, for example, silicone.

<FIG> is a side view illustrating an anti-wrinkle step in a method for manufacturing a secondary battery according to a third embodiment of the present invention.

Referring to <FIG> and <FIG>, a method for manufacturing a secondary battery <NUM> according to a third embodiment of the present invention comprises a forming step (S10) of forming a pouch sheet <NUM>, a folding step (S20) of folding the pouch sheet <NUM>, and an anti-wrinkle step (S30) of forming an anti-wrinkle bending part <NUM> on an outer shell of the pouch sheet <NUM>. Also, the method for manufacturing the secondary battery according to the third embodiment of the present invention may further comprise a sealing step of sealing an outer circumferential surface of the pouch sheet <NUM> after the folding step (S20).

The method for manufacturing the secondary battery according to the third embodiment of the present invention is the same as the method for manufacturing the secondary battery according to the first and second embodiments of the present invention except for an anti-wrinkle bending part <NUM> formed through an anti-wrinkle step (S30).

Thus, contents of this embodiment, which are duplicated with those according to the forgoing embodiments, will be briefly described, and also, differences therebetween will be mainly described.

In detail, in the method for manufacturing the secondary battery according to the third embodiment of the present invention, in the anti-wrinkle step (S30), a first sealing part <NUM> and a second sealing part of a pouch sheet <NUM> may be thermally compressed to form an anti-wrinkle bending part <NUM>.

Also, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent to have a plurality of bent portions.

Furthermore, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent in a semicircular shape. Here, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be formed so that convex portions of a plurality of semicircles are alternately arranged in an upward and downward direction. Here, for example, the anti-wrinkle bending part <NUM> may have a cross-section having a semicircular pulse shape.

Also, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent to have a first bent part 315a and a second bent part 315b. Here, in the anti-wrinkle step (S30), for example, the anti-wrinkle bending part <NUM> may be formed to have an "S"-shaped cross-section.

<FIG> is a side view illustrating an anti-wrinkle step in a method for manufacturing a secondary battery according to a fourth embodiment of the present invention.

Referring to <FIG> and <FIG>, a method for manufacturing a secondary battery <NUM> according to a fourth embodiment of the present invention comprises a forming step (S10) of forming a pouch sheet <NUM>, a folding step (S20) of folding the pouch sheet <NUM>, and an anti-wrinkle step (S30) of forming an anti-wrinkle bending part <NUM> on an outer shell of the pouch sheet <NUM>. Also, the method for manufacturing the secondary battery according to the fourth embodiment of the present invention may further comprise a sealing step of sealing an outer circumferential surface of the pouch sheet <NUM> after the folding step (S20).

The method for manufacturing the secondary battery according to the fourth embodiment of the present invention is the same as the method for manufacturing the secondary battery according to the first to third embodiments of the present invention except for an anti-wrinkle bending part <NUM> formed through an anti-wrinkle step (S30).

In detail, in the method for manufacturing the secondary battery according to the fourth embodiment of the present invention, in the anti-wrinkle step (S30), a first sealing part <NUM> and a second sealing part of a pouch sheet <NUM> may be thermally compressed to form an anti-wrinkle bending part <NUM>.

Also, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent to have a plurality of bent portions. Here, in the anti-wrinkle step (S30), for example, the anti-wrinkle bending part <NUM> may be bent in a bent shape. Furthermore, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent in a rectangular shape. Here, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be formed so that convex portions of a plurality of rectangular shapes are alternately arranged in an upward and downward direction. Here, for example, the anti-wrinkle bending part <NUM> may have a cross-section having a rectangular pulse shape.

Also, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be bent to have a first bent part 415a and a second bent part 415b. Here, for example, the first bent part 415a may be formed as a convex portion, and the second bent part 415b may be formed as a concave portion.

In the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be formed so that the bent portion is vertically formed with respect to the first sealing part <NUM> and the second sealing part, which are horizontally formed on one side and the other side surface of the battery case <NUM>. Here, in the anti-wrinkle step (S30), the anti-wrinkle bending part <NUM> may be formed at a folding part-side of each of the first sealing part <NUM> and the second sealing part, which are adjacent to the folding part.

Referring to <FIG> and <FIG>, the secondary battery <NUM> according to the first embodiment of the present invention comprises an electrode assembly <NUM> and a battery case <NUM> which accommodates the electrode assembly <NUM> therein and on which the anti-wrinkle bending part <NUM> is formed on an outer shell thereof.

The secondary battery <NUM> according to the first embodiment of the present invention relates to the secondary battery <NUM> manufactured through the method of manufacturing the secondary battery according to the foregoing first embodiment of the present invention, and thus, duplicated contents will be briefly described, and differences will be mainly described.

In the electrode assembly <NUM>, electrodes and separators may be alternately combined and stacked on each other.

The battery case <NUM> is formed by folding a pouch sheet <NUM> to accommodate the electrode assembly <NUM>.

Referring to <FIG>, an anti-wrinkle bending part <NUM> may be formed on an outer shell to prevent wrinkles from being generated on the battery case <NUM>.

Also, the anti-wrinkle bending part <NUM> may be bent to have a plurality of bent portions through thermal compression, thereby preventing the wrinkles from being generated on the outer shell of the battery case and portions that are in the vicinity of the outer shell. Here, the anti-wrinkle bending part <NUM> may be bent, for example, in a zigzag shape.

A folding part <NUM> may be formed at a first side 110a in a fourth direction on the outer shell of the battery case <NUM>, a first sealing part <NUM> and a second sealing part <NUM> may be formed at a second side 110b and a third side 110c in both directions of the folding part <NUM>, and the anti-wrinkle bending part <NUM> may be formed on the first sealing part <NUM> and the second sealing part <NUM>.

Also, the anti-wrinkle bending part <NUM> may be, for example, formed on the folding part <NUM> of each of the first sealing part <NUM> and the second sealing part <NUM> on the outer shell of the battery case <NUM>. That is, the anti-wrinkle bending part <NUM> may be formed at a portion of each of the first sealing part <NUM> and the second sealing part <NUM>, which is in the vicinity of the folding part <NUM>. Here, the anti-wrinkle bending part <NUM> may have, for example, a length corresponding to <NUM>% to <NUM>% of a length of each of the first sealing part <NUM> and the second sealing part <NUM>. Particularly, the anti-wrinkle bending part <NUM> may have, for example, a length corresponding to <NUM>% of a length of each of the first sealing part <NUM> and the second sealing part <NUM>.

Also, the anti-wrinkle bending part <NUM> may be formed over the entire first and second sealing parts <NUM> and <NUM> on the outer shell of the battery case <NUM>.

For another example, the anti-wrinkle bending part <NUM> may be formed at the folding part <NUM> on the outer shell of the battery case <NUM>.

Also, for another example, the anti-wrinkle bending part <NUM> may be formed at the first sealing part <NUM>, the second sealing part <NUM>, and the folding part <NUM> on the outer shell of the battery case <NUM>.

The anti-wrinkle bending part <NUM> may be bent to have a first bent part 115a and a second bent part 115b. Here, the anti-wrinkle bending part <NUM> may have, for example, an "N"-shaped cross-section.

The secondary battery <NUM> according to the first embodiment of the present invention may further comprise a shape retaining part <NUM> provided on an outer surface of the anti-wrinkle bending part <NUM> to retain a shape of the anti-wrinkle bending part <NUM>. Here, the shape retaining part <NUM> may prevent the anti-wrinkle bending part <NUM> from being deformed and also prevent the anti-wrinkle effect of the pouch sheet <NUM> from being deteriorated due to the deformation of the anti-wrinkle bending part <NUM>.

The shape retaining part <NUM> may be formed to be applied to the outer surface of the anti-wrinkle bending part <NUM>.

Here, the shape retaining part <NUM> may be made of an insulating material and a heat-resistance material. Here, the shape retaining part <NUM> may be made of, for example, silicone.

Referring to <FIG>, the secondary battery <NUM> according to the second embodiment of the present invention comprises an electrode assembly <NUM> and a battery case <NUM> which accommodates the electrode assembly <NUM> therein and on which the anti-wrinkle bending part <NUM> is formed on an outer shell thereof (see <FIG>).

The secondary battery <NUM> according to the second embodiment of the present invention is the same as the secondary battery according to the first embodiment of the present invention except for a bent shape of the anti-wrinkle bending part <NUM>.

Here, in the secondary battery <NUM> according to the second embodiment of the present invention, the anti-wrinkle bending part <NUM> may be bent in a bent shape.

Here, the anti-wrinkle bending part <NUM> may be bent to have a first bent part 215a, a second bent part 215b, and a third bent part 215c. Here, the anti-wrinkle bending part <NUM> may have, for example, a "W"-shaped cross-section.

The secondary battery <NUM> according to the second embodiment of the present invention may further comprise a shape retaining part <NUM> provided on an outer surface of the anti-wrinkle bending part <NUM> to retain a shape of the anti-wrinkle bending part <NUM>. Here, the shape retaining part <NUM> may prevent the anti-wrinkle bending part <NUM> from being deformed and also prevent the anti-wrinkle effect of the pouch sheet <NUM> from being deteriorated due to the deformation of the anti-wrinkle bending part <NUM>.

Referring to <FIG>, the secondary battery <NUM> according to the third embodiment of the present invention comprises an electrode assembly <NUM> and a battery case <NUM> which accommodates the electrode assembly <NUM> therein and on which the anti-wrinkle bending part <NUM> is formed on an outer shell thereof (see <FIG>).

The secondary battery <NUM> according to the third embodiment of the present invention is the same as the secondary batteries according to the first and second embodiments of the present invention except for a bent shape of an anti-wrinkle bending part <NUM>.

In detail, in the secondary battery according to the third embodiment of the present invention, the anti-wrinkle bending part <NUM> may be formed to have a plurality of bent portions.

Furthermore, the anti-wrinkle bending part <NUM> may be bent in a plurality of semicircular shapes. Here, the anti-wrinkle bending part <NUM> may be formed so that convex portions of a plurality of semicircles are alternately arranged in an upward and downward direction. Here, for example, the anti-wrinkle bending part <NUM> may have a cross-section having a semicircular pulse shape.

Also, the anti-wrinkle bending part <NUM> may be bent to have a first bent part 315a and a second bent part 315b. Here, the anti-wrinkle bending part <NUM> may be formed to have an "S"-shaped cross-section.

The secondary battery <NUM> according to the third embodiment of the present invention may further comprise a shape retaining part <NUM> provided on an outer surface of the anti-wrinkle bending part <NUM> to retain a shape of the anti-wrinkle bending part <NUM>. Here, the shape retaining part <NUM> may prevent the anti-wrinkle bending part <NUM> from being deformed and also prevent the anti-wrinkle effect of the pouch sheet <NUM> from being deteriorated due to the deformation of the anti-wrinkle bending part <NUM>.

Referring to <FIG>, the secondary battery <NUM> according to the fourth embodiment of the present invention comprises an electrode assembly <NUM> and a battery case <NUM> which accommodates the electrode assembly <NUM> therein and on which the anti-wrinkle bending part <NUM> is formed on an outer shell thereof (see <FIG>).

The secondary battery <NUM> according to the fourth embodiment of the present invention is the same as the secondary batteries according to the first to third embodiments of the present invention except for a bent shape of an anti-wrinkle bending part <NUM>.

In detail, in the secondary battery according to the fourth embodiment of the present invention, the anti-wrinkle bending part <NUM> may be formed to have a plurality of bent portions.

Also, the anti-wrinkle bending part <NUM> may be, for example, bent in a bent shape. Here, the anti-wrinkle bending part <NUM> may be bent in a plurality of rectangular shapes. Here, the anti-wrinkle bending part <NUM> may be formed so that convex portions of a plurality of rectangles are alternately arranged in an upward and downward direction. Here, for example, the anti-wrinkle bending part <NUM> may have a cross-section having a rectangular pulse shape.

Also, the anti-wrinkle bending part <NUM> may be formed to comprise a first bent part 415a and a second bent part 415b. Here, for example, the first bent part 415a may be formed as a convex portion, and the second bent part 415b may be formed as a concave portion.

The secondary battery <NUM> according to the fourth embodiment of the present invention may further comprise a shape retaining part <NUM> provided on an outer surface of the anti-wrinkle bending part <NUM> to retain a shape of the anti-wrinkle bending part <NUM>. Here, the shape retaining part <NUM> may prevent the anti-wrinkle bending part <NUM> from being deformed and also prevent the anti-wrinkle effect of the pouch sheet <NUM> from being deteriorated due to the deformation of the anti-wrinkle bending part <NUM>.

Here, the shape retaining part <NUM> may be applied to the outer surface of the anti-wrinkle bending part <NUM>.

<FIG> is a side view illustrating a state before pressing through a pressing block for the secondary battery according to the first embodiment of the present invention, <FIG> is a side view illustrating a state during the pressing through the pressing block for the secondary battery according to the first embodiment of the present invention, and <FIG> is a side view illustrating a state after the pressing through the pressing block for the secondary battery according to the first embodiment of the present invention.

Referring to <FIG>, a pressing block <NUM> for the secondary battery according to the first embodiment of the present invention may be provided in plurality, and the plurality of pressing blocks <NUM> may move in a direction facing each other to press an outer shell of the pouch sheet <NUM> in which the electrode assembly <NUM> is accommodated. Here, the pressing block <NUM> may comprise a first pressing block <NUM> and a second pressing block <NUM>, which move in the direction facing each other to press the outer shell (see <FIG>).

Also, when the pressing block <NUM> presses the outer shell of the pouch sheet <NUM>, bending formation parts <NUM> and <NUM> are formed on a pressing surface of the pressing block <NUM> so that an anti-wrinkle bending part <NUM> is formed on the outer shell.

Here, the bending formation parts <NUM> and <NUM> may comprise convex parts <NUM> and <NUM> and concave parts <NUM> and <NUM> to form the anti-wrinkle bending part <NUM> on the outer shell when pressing. Here, the convex parts <NUM> and <NUM> may protrude from the pressing surface, and the concave parts <NUM> and <NUM> may be formed as grooves that are recessed from the pressing surface. Here, to form the anti-wrinkle bending part <NUM> on the outer shell by using the convex parts <NUM> and <NUM> and the concave parts <NUM> and <NUM>, each of the convex parts <NUM> and <NUM> may protrude in a triangular shape, and each of the concave parts <NUM> and <NUM> may be recessed in a triangular shape.

Also, the bending formation parts <NUM> and <NUM> formed in the first pressing block <NUM> and the second pressing block <NUM> may be formed in shapes corresponding to each other in the direction facing each other.

Also, each of the bending formation parts <NUM> and <NUM> may have, for example, an "N"-shaped cross-section.

The pressing block <NUM> for the secondary battery according to the first embodiment of the present invention may further comprise heaters <NUM> and <NUM> for transferring heat to the plurality of pressing blocks <NUM>. Thus, the heat may be applied to the outer shell of the pouch sheet <NUM> to perform thermal compression through the plurality of pressing blocks <NUM>.

<FIG> is a side view illustrating a state during pressing through a pressing block for the secondary battery according to the second embodiment of the present invention, and <FIG> is a side view illustrating a state after the pressing through the pressing block for the secondary battery according to the second embodiment of the present invention.

Referring to <FIG>, a pressing block <NUM> for the secondary battery according to the second embodiment of the present invention may be provided in plurality, and the plurality of pressing blocks <NUM> may move in a direction facing each other to press a first sealing part <NUM> and a second sealing part of the pouch sheet <NUM> in which the electrode assembly is accommodated. Here, the pressing block <NUM> may comprise a first pressing block <NUM> and a second pressing block <NUM>, which move in a direction facing each other to press a first sealing part <NUM> and a second sealing part.

The pressing block <NUM> for the secondary battery according to the second embodiment of the present invention is the same as the pressing block for the secondary battery according to the first embodiment of the present invention except for a shape of each of bending formation parts <NUM> and <NUM>.

Here, in the pressing block <NUM> for the secondary battery according to the second embodiment of the present invention, the bending formation parts <NUM> and <NUM> may comprise convex parts <NUM>, <NUM>, and <NUM> and concave parts <NUM>, <NUM>, and <NUM> to form an anti-wrinkle bending part <NUM> on a first sealing part <NUM> and a second sealing part when pressing. Here, the convex parts <NUM>, <NUM>, and <NUM> may protrude from the pressing surface, and the concave parts <NUM>, <NUM>, and <NUM> may be formed as grooves that are recessed from the pressing surface. Here, to form the anti-wrinkle bending part <NUM> on the first sealing part <NUM> and the second sealing part by using the convex parts <NUM>, <NUM>, and <NUM> and the concave parts <NUM>, <NUM>, and <NUM>, each of the convex parts <NUM>, <NUM>, and <NUM> may protrude in a triangular shape, and each of the concave parts <NUM>, <NUM>, and <NUM> may be recessed in a triangular shape.

Also, each of the bending formation parts <NUM> and <NUM> may have, for example, a "W"-shaped cross-section.

<FIG> is a side view illustrating a state after pressing through a pressing block for the secondary battery according to the third embodiment of the present invention.

Referring to <FIG>, a pressing block <NUM> for the secondary battery according to the third embodiment of the present invention may be provided in plurality, and the plurality of pressing blocks <NUM> may move in a direction facing each other to press a first sealing part <NUM> and a second sealing part of the pouch sheet <NUM> in which the electrode assembly is accommodated. Here, the pressing block <NUM> may comprise a first pressing block <NUM> and a second pressing block <NUM>, which move in a direction facing each other to press a first sealing part <NUM> and a second sealing part.

The pressing block <NUM> for the secondary battery according to the third embodiment of the present invention is the same as the pressing block for the secondary battery according to the first embodiment of the present invention except for a shape of each of bending formation parts <NUM> and <NUM>.

In more detail, in the pressing block <NUM> for the secondary battery according to the third embodiment of the present invention, the bending formation parts <NUM> and <NUM> may comprise convex parts <NUM> and <NUM> and concave parts <NUM> and <NUM> to form an anti-wrinkle bending part <NUM> on a first sealing part <NUM> and a second sealing part when pressing.

The convex parts <NUM> and <NUM> may protrude from the pressing surface, and the concave parts <NUM> and <NUM> may be formed as grooves that are recessed from the pressing surface. Also, to form the anti-wrinkle bending part <NUM> on the first sealing part <NUM> and the second sealing part by using the convex parts <NUM> and <NUM> and the concave parts <NUM> and <NUM>, each of the convex parts <NUM> and <NUM> may protrude in a semicircular shape, and each of the concave parts <NUM> and <NUM> may be recessed in a semicircular shape. Here, for example, each of the bending formation parts <NUM> and <NUM> may have a cross-section having a semicircular pulse shape. Here, each of the bending formation parts <NUM> and <NUM> may have, for example, an "S"-shaped cross-section.

<FIG> is a side view illustrating a state after pressing through a pressing block for the secondary battery according to the fourth embodiment of the present invention.

Referring to <FIG>, a pressing block <NUM> for the secondary battery according to the fourth embodiment of the present invention may be provided in plurality, and the plurality of pressing blocks <NUM> may move in a direction facing each other to press and compress a first sealing part <NUM> and a second sealing part of the pouch sheet <NUM> in which the electrode assembly is accommodated. Here, the pressing block <NUM> may comprise a first pressing block <NUM> and a second pressing block <NUM>, which move in a direction facing each other to press a first sealing part <NUM> and a second sealing part.

The pressing block <NUM> for the secondary battery according to the fourth embodiment of the present invention is the same as the pressing block for the secondary battery according to the first to third embodiments of the present invention except for a shape of each of bending formation parts <NUM> and <NUM>.

In more detail, in the pressing block <NUM> for the secondary battery according to the fourth embodiment of the present invention, the bending formation parts <NUM> and <NUM> may comprise convex parts <NUM> and <NUM> and concave parts <NUM> and <NUM> to form an anti-wrinkle bending part <NUM> on a first sealing part <NUM> and a second sealing part when pressing.

The convex parts <NUM> and <NUM> may protrude from the pressing surface, and the concave parts <NUM> and <NUM> may be formed as grooves that are recessed from the pressing surface. Also, to form the anti-wrinkle bending part <NUM> on the first sealing part <NUM> and the second sealing part by using the convex parts <NUM> and <NUM> and the concave parts <NUM> and <NUM>, each of the convex parts <NUM> and <NUM> may protrude in a rectangular shape, and each of the concave parts <NUM> and <NUM> may be recessed in a rectangular shape. Here, each of the bending formation parts <NUM> and <NUM> may have, for example, a cross-section having a rectangular pulse shape.

Electrodes and separators were alternately combined with each other to manufacture an electrode assembly.

A pouch sheet was formed to form an accommodation part so that the electrode assembly is accommodated and then was folded after the manufactured electrode assembly is accommodated in the accommodation part to form a battery case.

Here, an anti-wrinkle bending part having a "W" shape was formed on an outer shell to prevent wrinkles from being generated on the outer shell of the battery case. Here, the anti-wrinkle bending part was formed on a first sealing part and a second sealing part on the outer shell of the battery case so that the anti-wrinkle bending part is formed on a position of each of the first sealing part and the second sealing part, which is disposed at an opposite side of a portion through which a gas is discharged.

Thereafter, an electrolyte was accommodated in the battery case that is formed by forming and folding the pouch sheet, and then, the battery case was sealed to manufacture the secondary battery.

A secondary battery was manufactured through the same method as the manufacturing example except for the anti-wrinkle bending part having the "W" shape is not formed on the outer wall of the battery case.

<FIG> is a planar image of a secondary battery manufactured according to a comparative example, and <FIG> is a planar image of a secondary battery manufactured according to a manufacturing example.

In the battery case of the secondary battery, it was seen that bat-ear type wrinkles are generated on the outer shell and in the vicinity of the outer shell.

Referring to <FIG>, according to the results, in the comparative example, the bat-ear type wrinkles <NUM> were generated on the outer shell <NUM> of the battery case <NUM>. On the other hand, referring to <FIG>, in the manufacturing example, it was observed that no bat-ear type wrinkles are generated on the sides of the first sealing part <NUM> and the second sealing part, on which the anti-wrinkle bending part <NUM> is formed. Particularly, as the results of repetitive experiments, it was observed that the bat-ear type wrinkles of about <NUM> or more in comparison with the comparative example were reduced in the manufacturing examples.

As a result, it may be seen that the generation of the wrinkles in the battery case in the manufacturing example is remarkably reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, this is for the purpose of specifically describing the present invention, and thus, the secondary battery, the method for manufacturing the same, and the pressing block for manufacturing the secondary battery according to the present application are not limited thereto. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the invention.

Claim 1:
A method for manufacturing a secondary battery (<NUM>), the method comprising:
a forming step of forming a pouch sheet (<NUM>) to form an accommodation part (<NUM>) in which an electrode assembly (<NUM>) is accommodated;
a folding step of folding the pouch sheet (<NUM>) with respect to a folding part (<NUM>) so that the electrode assembly (<NUM>) is accommodated in the accommodation part (<NUM>), and the accommodation part (<NUM>) is blocked from the outside to form a battery case; and
an anti-wrinkle step of forming an anti-wrinkle bending part (<NUM>) on an outer shell to prevent wrinkles from being generated on the outer shell of the folded pouch sheet (<NUM>),
wherein, in the anti-wrinkle step, the anti-wrinkle bending part (<NUM>) is bent to have a plurality of bent portions,
wherein the battery case comprises the accommodation part (<NUM>) and a gas pocket part (<NUM>) having a passage extending from the accommodation part (<NUM>),
the folding part (<NUM>) is formed at a first side (110a), the gas pocket part (<NUM>) is formed at a fourth side (110d) that is opposite to the folding part (<NUM>), a first sealing part (<NUM>) is formed at a second side (110b), and a second sealing part (<NUM>) is formed at a third side (110c) in four directions on the outer shell of the battery case, and
in the anti-wrinkle step, the anti-wrinkle bending part (<NUM>) is formed at a portion of each of the first sealing part (<NUM>) and the second sealing part (<NUM>), which is in the vicinity of the folding part (<NUM>).