Patent Description:
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. The secondary battery accommodates an electrode assembly and an electrolyte. 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.

In an activation process in the process of manufacturing the secondary battery, a solid electrolyte interface (SEI layer) is generated through an electrochemical reaction between an electrode active material and an electrolyte, and as a result, an activation gas is generated as a by-product.

The generated activation gas is removed through a degassing process, but if the gas remains in a cell due to degassing defects, a gasp trap is generated. Thus, the gas trap causes a problem in which lithium precipitation occurs in a subsequent charging/discharging process.

[Prior Art Document] (Patent Document) <CIT>.

Documents <CIT> and <CIT> relate to the degassing of battery cells.

One aspect of the present invention is to provide a method and apparatus for manufacturing a secondary battery, which are capable of effectively removing an internal gas.

To this end, the invention relates to a method for manufacturing a secondary battery, according to claim <NUM>.

The method after the invention may present one or more of the features of dependent claims <NUM> to <NUM>, in any combination allowed by the claims.

The invention also relates to an apparatus for manufacturing a secondary battery, according to claim <NUM>.

The apparatus after the invention may present one or more of the features of dependent claims <NUM> to <NUM>, in any combination allowed by the claims.

According to the present invention, the body of the pouch may be pressed through the pressing process. Here, the body of the pouch may be pressed through the pressing roll in the full-length direction of the cell, and thus, the internal gas of the electrode assembly accommodated in the body may be easily discharged to the outside of the electrode assembly.

In addition, when the portion except for the edge of the body is pressed through the pressing roll, the internal gas between the electrode and the separator at the central portion in the electrode assembly may be easily discharged to the outside of the electrode assembly through the edge of the electrode assembly. Therefore, the phenomenon in which the gas within the electrode assembly remains to form the gas trap may be prevented from occurring to prevent the lithium from being precipitated in the subsequent charge/discharge process. In addition, the edge of the electrode assembly, which are capable of being easily ruptured or damaged, may not be pressed to prevent the electrode assembly from being damaged due to the pressing process.

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. 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 plan view illustrating an accommodation process in a method for manufacturing a secondary battery according to an embodiment of the present invention, <FIG> is a plan view illustrating an accommodation process in the method for manufacturing the secondary battery according to an embodiment of the present invention, <FIG> is a perspective view illustrating a pressing process in the method for manufacturing the secondary battery according to an embodiment of the present invention, and <FIG> is a perspective view illustrating a pressing process in the method for manufacturing the secondary battery according to an embodiment of the present invention. Here, <FIG> is a perspective view when viewed in a direction different from that in <FIG>.

Referring to <FIG>, a method for manufacturing a secondary battery according to an embodiment of the present invention comprises an accommodation process of accommodating an electrode assembly <NUM> in a pouch <NUM> to form a cell <NUM>, an activation process of activating the cell <NUM>, a pressing process of roll-pressing the cell <NUM>, and a degassing process of discharging an internal gas of the cell <NUM>. In addition, the method for manufacturing the secondary battery according to an embodiment of the present invention may further comprise an aging process of allowing the cell <NUM> to elapse for a predetermined time and a sealing process of sealing the pouch <NUM>.

In more detail, referring to <FIG>, the cell <NUM> comprises a pouch <NUM> and an electrode assembly <NUM> accommodated in an accommodation part <NUM> of the pouch <NUM>. Here, the electrode assembly <NUM> may comprise electrode leads <NUM> and <NUM> electrically connected to electrodes.

The electrode assembly <NUM> may be a chargeable and dischargeable power generation element and be formed by alternately stacking electrodes and separators.

The electrodes may be constituted by a positive electrode and a negative electrode. At this time, the electrode assembly <NUM> may have a structure in which the positive electrode/separator/negative electrode are alternately stacked.

For example, in the plan view, the positive electrode may be formed to be larger than the negative electrode. Here, for example, the negative electrode may be formed to have a length and width, each of which is larger by <NUM> to <NUM> than each of those of the positive electrode. Here, more specifically, for example, the negative electrode may be formed to have a length and width, each of which is larger by about <NUM> than each of those of the positive electrode. That is, when the positive electrode, the separator, and the negative electrode are stacked, an end of the negative electrode in a lateral direction may further protrude by about <NUM> than an end of the positive electrode.

Also, the electrode leads <NUM> and <NUM> may comprise a positive electrode lead <NUM> connected to the positive electrode and a negative electrode lead <NUM> connected to the negative electrode.

The positive electrode may comprise a positive electrode collector and a positive electrode active material stacked on the positive electrode collector.

The positive electrode collector may be made of an aluminum foil.

The positive electrode active material may comprise lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound or mixture containing at least one of the above-described materials.

The negative electrode may comprise a negative electrode collector and a negative active material stacked on the negative electrode collector.

The negative electrode collector may be made of, for example, a foil made of a copper (Cu) material.

The negative active material may be a compound or a mixture containing a graphite-based material.

The separator is made of an insulating material to electrically insulates the positive electrode and the negative electrode from each other. Here, the separator may be made of a polyolefin-based resin film such as polyethylene or polypropylene having microporosity.

Referring to <FIG> and <FIG>, in the accommodation process, the electrode assembly <NUM>, the electrolyte, and one side portion of each of the electrode leads <NUM> and <NUM> connected to the electrodes may be accommodated in the accommodation part <NUM> formed in the pouch <NUM> to form the cell <NUM>.

In addition, in the accommodation process, the other side portion of each of the electrode leads <NUM> and <NUM> may be accommodated to protrude to the outside of the pouch <NUM>.

Here, the pouch <NUM> comprises a body <NUM> in which the accommodation part <NUM>, in which the electrode assembly <NUM> is accommodated, is formed, and a gas pocket part <NUM> extending from the accommodation part <NUM> to collect a gas generated in the accommodation part <NUM>. In addition, the gas pocket part <NUM> may extend in a full-width direction W of the cell <NUM>. Here, the full-width direction W of the cell <NUM> may be perpendicular to a full-length direction T, which is a protrusion direction of the electrode leads <NUM> and <NUM> in the plan view. In this case, the electrode assembly <NUM> may have, for example, a length greater than a width. That is, the electrode assembly <NUM> may be formed so that the length of the cell <NUM> in the full-length direction T is greater than the width in the full-width direction W of the cell <NUM>.

In the activation process, the cell <NUM> is charged to be activated. Here, in the activation process, the cell <NUM> may be charged by connecting electricity to the electrode leads <NUM> and <NUM> of the cell <NUM>.

<FIG> is a front view illustrating a pressing process in the method for manufacturing the secondary battery according to an embodiment of the present invention.

Referring to <FIG>, in the pressing process, after the activation process, the cell <NUM> is sequentially pressed through pressing rolls <NUM> to perform a roll press.

In addition, in the pressing process, the cell <NUM> may be roll-pressed in the full-length direction T of the cell <NUM>, which is the protrusion direction of the electrode leads <NUM> and <NUM>.

In the pressing process, the body <NUM> of the pouch <NUM> is pressed.

In the pressing process, after disposing the cell <NUM> between the pair of pressing rolls <NUM>, the pair of pressing rolls <NUM> may sequentially press both surfaces of the cell <NUM>. Here, the pressing roll <NUM> may be in line contact with the cell <NUM>. Thus, when the cell <NUM> is pressed through the pressing rolls <NUM> while being rolled, a linear pressure is sequentially applied to an outer surface of the cell <NUM>. Thus, the gas disposed inside the electrode assembly <NUM> may be easily discharged to the outside of the electrode assembly <NUM>.

Here, the pair of pressing rolls <NUM> may comprise a first roll <NUM> for pressing an upper portion of the cell <NUM> and a second roll <NUM> for pressing a lower portion of the cell <NUM>. In addition, the first roll <NUM> and the second roll <NUM> may be supported by supports <NUM> and <NUM>. At this time, in the pressing process, the support <NUM> supporting the first roll <NUM> may move vertically by a moving means, and thus, the upper portion of the cell <NUM> may be pressed through the first roll <NUM>. Here, the moving means may be, for example, a pneumatic or hydraulic actuator.

In the pressing process, for example, a tab or the pouch <NUM> of the cell <NUM> may be held and fixed through a fixing means to press the cell <NUM> while the pressing roll <NUM> moves. In this case, the fixing means may be, for example, a fixing jig.

In addition, as another example of the pressing process, the cell <NUM> may be input between the pair of pressing rolls <NUM> so as to be pressed.

Furthermore, in the pressing process, the pair of pressing rolls <NUM> may be provided as one roll set, and also, one or more roll sets may be provided.

In the pressing process, the pair of pressing rolls <NUM> may be provided at a horizontal position.

In addition, in the pressing process, a gap between the pair of pressing rolls <NUM> may be adjusted. Here, in the pressing process, a distance between the pair of pressing rolls <NUM> may be maintained within a predetermined gap range.

Furthermore, in the pressing process, pressing force applied to the cell <NUM> through the pressing rolls <NUM> may be adjusted. Here, in the pressing process, the pressing force applied to the cell <NUM> may be maintained within a predetermined pressure range. At this time, the pressing process may be performed so that the pressing force of the pressing roll <NUM> for pressing the cell <NUM> ranges of <NUM> kgf to <NUM> kgf. In addition, a load pressed to the cell <NUM> may be detected through a load cell <NUM> provided on the support <NUM> supporting the pressing roll <NUM>. Here, for example, the load cell <NUM> may be provided on the support <NUM> supporting the second roll <NUM> disposed below the cell <NUM>.

In the pressing process, a portion except for an edge of the body <NUM> in the pouch <NUM> may be pressed in the full-width direction W of the cell <NUM>.

In addition, in the pressing process, the pressing roll <NUM> may be formed to have a diameter of each of both side portions 11d and 12d, which is smaller than a diameter of each of central portions 11a and 12a.

In this case, in the pressing process, a length b of the central portion of the pressing roll <NUM> may be provided to be smaller than a width a of the body <NUM>. That is, in the pressing process, the length b of the central portion of the pressing roll <NUM>, which is parallel to the full-length direction T of the cell <NUM>, may be provided to be smaller than the width a of the body <NUM> of the pouch <NUM>, which is parallel to the full-length direction T of the cell <NUM> so that the portion except for the edge of the body <NUM> is pressed. At this time, the width a of the body <NUM> may be, for example, a width of a bottom surface of the accommodation part <NUM> in the pouch <NUM>. Here, the width a of the body <NUM> in the pouch <NUM> may correspond to, for example, a width of the electrode assembly <NUM>.

Here, both side portions 11d and 12d of the pressing roll <NUM> may comprise one side portion 11b disposed at one side in the full-width direction W of the cell <NUM> and the other side portion 11c disposed at the other side.

In addition, in the pressing process, each of both side portions 11d and 12d of the pressing roll <NUM> may be formed to have a diameter that is gradually smaller toward an end thereof.

Here, in the pressing process, an outer surface of each of both the side portions 11d and 12d of the pressing roll <NUM> may have a curvature that is rounded from each of the central portions 11a and 12a toward each of the ends. That is, in the pressing roller <NUM>, the curvature may be formed at a corner of each of both the side portions 11d and 12d in the full-width direction W of the cell <NUM>. Thus, in the electrode assembly <NUM> accommodated in the body <NUM>, a central portion except for the edge in the full-length direction T of the cell <NUM> may be pressed by the central portions 11a and 12a of the pressing roll <NUM>. Thus, the gas disposed in the central portion of the electrode assembly <NUM> may move to the edge of the electrode assembly <NUM> and then be discharged to the outside of the electrode assembly <NUM>. Here, the gas discharged to the outside of the electrode assembly <NUM> may be disposed in the accommodation part <NUM> or the gas pocket part <NUM> inside the pouch <NUM> and then be discharged to the outside of the pouch <NUM> through the degassing process.

At this time, the rounded curvature formed on the outer surfaces of each of both the side portions 11d and 12d in the pressing roll <NUM> may be formed to have a curvature radius R of <NUM> to <NUM>.

Thus, the curvature radius R is formed to be <NUM> or more, which is a lower limit value to prevent press marks on the battery and also prevent the battery from being damaged by the edge of the pressing roll <NUM>. In addition, since the curvature radius R is formed to be less than <NUM> or less, which is an upper limit value, and thus. the pressing effect for removing the gas at the outer shell of the battery may not be deteriorated.

In the aging process, after the activation process, the cell <NUM> may elapse for a predetermined time. Here, in the aging process, the cell <NUM> may elapse for a predetermined time at room temperature and a high temperature. In this case, the aging process may be performed before the degassing process.

The pressing process may be performed during the aging process.

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

Referring to <FIG>, in the sealing process, after the degassing process, an outer circumferential surface of the pouch <NUM> may be sealed to manufacture a secondary battery <NUM>'.

In this case, in the sealing process, the gas pocket part <NUM> may be cut to be removed, and then, the removed portion may be sealed through thermal fusion to seal the pouch <NUM>.

Referring to <FIG> and <FIG>, in the method for manufacturing the secondary battery according to an embodiment of the present invention, which is configured as described above, the body <NUM> of the pouch <NUM> may be pressed through the pressing process Here, the body <NUM> may be pressed through the pressing rolls <NUM> in the full-length direction T of the cell <NUM> to easily discharge the internal gas of the electrode assembly <NUM> accommodated in the body <NUM> to the outside of the electrode assembly <NUM>.

Here, when the portion except for the edge of the body <NUM> is pressed through the pressing rolls <NUM>, the central portion of the electrode assembly <NUM> accommodated in the body <NUM> may be pressed, and thus, the internal gas between the electrode and the separator at the central portion in the electrode assembly <NUM> may be easily discharged to the outside of the electrode assembly <NUM> through the edge of the electrode assembly <NUM>. Therefore, the phenomenon in which the gas within the electrode assembly <NUM> remains to form the gas trap may be prevented from occurring to prevent the lithium from being precipitated in the subsequent charge/discharge process. In addition, the edge of the electrode assembly <NUM>, which are capable of being easily ruptured or damaged, may not be pressed to prevent the electrode assembly <NUM> from being damaged due to the pressing process.

Hereinafter, a method for manufacturing a secondary battery according to another embodiment of the present invention will be described.

<FIG> is a front view illustrating a pressing process in a method for manufacturing a secondary battery according to another embodiment of the present invention.

Referring to <FIG>, <FIG>, and <FIG>, a method for manufacturing a secondary battery according to another embodiment of the present invention comprises an accommodation process of accommodating an electrode assembly <NUM> in a pouch <NUM> to form a cell <NUM>, an activation process of activating the cell <NUM>, a pressing process of roll-pressing the cell <NUM>, and a degassing process of discharging an internal gas of the cell <NUM>.

In addition, the method for manufacturing the secondary battery according to another embodiment of the present invention may further comprise an aging process of allowing the cell <NUM> to elapse for a predetermined time and a sealing process of sealing the pouch <NUM>.

The method for manufacturing the secondary battery according to another embodiment of the present invention is different from the method for manufacturing the secondary battery according to the foregoing embodiment of the present invention in embodiment of a pressing process. Thus, contents of this embodiment, which are duplicated with those according to the forgoing embodiment, will be omitted or briefly described, and also, differences therebetween will be mainly described.

In more detail, in the method for manufacturing the secondary battery according to another embodiment of the present invention, in an accommodation process, an electrode assembly <NUM>, an electrolyte, and one side portion of each of the electrode leads <NUM> and <NUM> connected to the electrodes may be accommodated in an accommodation part <NUM> formed in a pouch <NUM> to form a cell <NUM>.

Here, the pouch <NUM> may comprise a body <NUM> in which the accommodation part <NUM>, in which the electrode assembly <NUM> is accommodated, is formed, and a gas pocket part <NUM> extending from the accommodation part <NUM> to collect a gas generated in the accommodation part <NUM>. In addition, the gas pocket part <NUM> may extend in a full-width direction W of the cell <NUM>.

In the pressing process, after the activation process, the cell <NUM> is sequentially pressed through pressing rolls <NUM> to perform a roll press.

In addition, in the pressing process, the cell <NUM> may be roll-pressed in a full-length direction T of the cell <NUM>, which is the protrusion direction of the electrode leads <NUM> and <NUM>. Here, in the pressing process, the body <NUM> of the pouch <NUM> may be pressed.

Furthermore, in the pressing process, after disposing the cell <NUM> between the pair of pressing rolls <NUM>, the pair of pressing rolls <NUM> may sequentially press both surfaces of the cell <NUM>. Here, the pressing roll <NUM> may be in line contact with the cell <NUM>. Thus, when the cell <NUM> is pressed through the pressing rolls <NUM> while being rolled, a linear pressure is sequentially applied to an outer surface of the cell <NUM>. Thus, the gas disposed inside the electrode assembly <NUM> may be easily discharged to the outside of the electrode assembly <NUM>. Here, the pair of pressing rolls <NUM> may comprise a first roll <NUM> for pressing an upper portion of the cell <NUM> and a second roll <NUM> for pressing a lower portion of the cell <NUM>.

Also, in the pressing process, a portion except for an edge of the body <NUM> in the pouch <NUM> may be pressed in the full-width direction W.

In addition, in the pressing process, a length c of the pressing roll <NUM> may be provided to be smaller than a width a of the body <NUM>.

That is, in the pressing process, the length c of the pressing roll <NUM>, which is parallel to the full-length direction T of the cell <NUM>, may be provided to be smaller than the width a of the body <NUM> in the pouch <NUM>, which is parallel to the full-length direction T of the cell <NUM> so that the portion except for the edge of the body <NUM> is pressed.

Thus, in the electrode assembly <NUM> accommodated in the body <NUM>, a central portion except for the edge in the full-length direction T of the cell <NUM> may be pressed by the pressing roll <NUM>. Thus, the gas disposed in the central portion of the electrode assembly <NUM> may move to the edge of the electrode assembly <NUM> and then be discharged to the outside of the electrode assembly <NUM>.

The length c of the pressing roll <NUM> may be formed, for example, to be smaller by <NUM> to <NUM> than the width a of the body <NUM> in the pouch <NUM>.

Thus, the length c of the pressing roll <NUM> may be formed to be smaller by <NUM> or more, which is a lower limit value, than the width a of the body <NUM> to prevent an outer shell of the electrode assembly <NUM> from being damaged. That is, when the electrode assembly <NUM> in which a negative electrode is formed to be larger than a positive electrode is pressed in a stacking direction, the negative electrode may be prevented from being damaged by an edge of the positive electrode. In addition, the length c of the pressing roll <NUM> may be formed to be smaller by <NUM> or less, which an upper limit value, than the width a of the body <NUM> to prevent a gas removal effect at an outer shell-side of the battery from being deteriorated.

Hereinafter, a method for manufacturing a secondary battery according to further another embodiment of the present invention will be described.

<FIG> is a front view illustrating a pressing process in a method for manufacturing a secondary battery according to further another embodiment of the present invention.

Referring to <FIG>, a method for manufacturing a secondary battery according to further another embodiment of the present invention comprises an accommodation process of accommodating an electrode assembly <NUM> in a pouch <NUM> to form a cell <NUM>, an activation process of activating the cell <NUM>, a pressing process of roll-pressing the cell <NUM>, and a degassing process of discharging an internal gas of the cell <NUM>.

In addition, the method for manufacturing the secondary battery according to further another embodiment of the present invention may further comprise an aging process of allowing the cell <NUM> to elapse for a predetermined time and a sealing process of sealing the pouch <NUM>.

The method for manufacturing the secondary battery according to further another embodiment of the present invention is different from the method for manufacturing the secondary battery according to the foregoing embodiments of the present invention in embodiment of a pressing process. Thus, contents of this embodiment, which are duplicated with those according to the forgoing embodiment, will be omitted or briefly described, and also, differences therebetween will be mainly described.

In more detail, in the method for manufacturing the secondary battery according to further embodiment of the present invention, in the accommodation process, the electrode assembly <NUM>, the electrolyte, and one side portion of each of electrode leads <NUM> and <NUM> connected to electrodes may be accommodated in an accommodation part <NUM> formed in the pouch <NUM> to form the cell <NUM>.

In addition, in the pressing process, the pair of pressing rolls <NUM> may be provided at a horizontal position.

In addition, in the pressing process, each of both side portions 31d and 32d of the pressing roll <NUM> may be formed to have a diameter that is gradually smaller toward an end thereof. Here, both side portions 31d and 32d of the pressing roll <NUM> may comprise one side portion 31b disposed at one side in the full-width direction W of the cell <NUM> and the other side portion 31c disposed at the other side. In this case, in the pressing process, a length d of each of central portions 31a and 32a of the pressing roll <NUM> may be provided to be smaller than a width a of the body <NUM>.

Furthermore, in the pressing process, each of both the side portions 31d and 32d of the pressing roll <NUM> may be chamfered. That is, in the pressing process, a corner of an outer circumferential surface of each of both the side portions 31d and 32d of the pressing roll <NUM> may be formed to have an inclined surface having a diameter that is gradually smaller toward an end thereof.

Hereinafter, an apparatus for manufacturing a secondary battery according to an embodiment of the present invention will be described.

Referring to <FIG> and <FIG>, an apparatus for manufacturing a secondary battery according to an embodiment of the present invention comprises a pressing roll <NUM> pressing a cell <NUM>, in which an electrode assembly <NUM> and an electrolyte are accommodated in a pouch <NUM>, and a support supporting the pressing roll <NUM>. The pressing roll <NUM> performs roll press on the cell <NUM> in a full-length direction T of the cell <NUM> to manufacture a secondary battery.

The apparatus for manufacturing the rechargeable battery according to an embodiment of the present invention relates to an apparatus for manufacturing a secondary battery that is applied to the method for manufacturing the secondary battery according to the foregoing embodiment. Thus, contents according to this embodiment, which are duplicated with the method for manufacturing the secondary battery according to the foregoing embodiment, will be omitted or briefly described, and also, differences therebetween will be mainly described.

In more detail, the pressing roll <NUM> may sequentially press the cell <NUM>, in which the electrode assembly <NUM> and the electrolyte are accommodated in the pouch <NUM>, before a degassing process after an activation process to perform roll press.

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

One side portion of each of electrode leads <NUM> and <NUM> connected to the electrodes may be accommodated in the pouch <NUM>, and the other side may protrude to the outside of the pouch <NUM>. At this time, the pressing roll <NUM> may perform the roll press in a full-length direction T of the cell <NUM> which is a protrusion direction of the electrode leads <NUM> and <NUM>.

Also, the pouch <NUM> may comprise a body <NUM> in which the accommodation part <NUM>, in which the electrode assembly <NUM> is accommodated, is formed, and a gas pocket part <NUM> extending from the accommodation part <NUM> to collect a gas generated in the accommodation part <NUM>. In addition, the gas pocket part <NUM> may extend in a full-width direction W of the cell <NUM>. Here, the full-width direction W of the cell <NUM> may be perpendicular to a full-length direction T, which is a protrusion direction of the electrode leads <NUM> and <NUM> in the plan view.

Also, the pressing roll <NUM> may be provided in a pair. After disposing the cell <NUM> between the pair of pressing rolls <NUM>, the pair of pressing rolls <NUM> may sequentially press both surfaces of the cell <NUM>. Here, the pressing roll <NUM> may be in line contact with the cell <NUM>. Thus, when the cell <NUM> is pressed through the pressing rolls <NUM> while being rolled, a linear pressure is sequentially applied to an outer surface of the cell <NUM>. Thus, the gas disposed inside the electrode assembly <NUM> may be easily discharged to the outside of the electrode assembly <NUM>.

Here, the pair of pressing rolls <NUM> may comprise a first roll <NUM> for pressing an upper portion of the cell <NUM> and a second roll <NUM> for pressing a lower portion of the cell <NUM>.

The pressing roll <NUM> may press a portion except for an edge of the body <NUM> in the pouch <NUM> in the full-width direction W of the cell <NUM>. For this, the pressing roll <NUM> may be formed to have a diameter of each of both side portions 11d and 12d, which is smaller than a diameter of each of central portions 11a and 12a.

Here, a length b of the central portion of the pressing roll <NUM> may be provided to be smaller than a width a of the body <NUM>. That is, the length b of the central portion of the pressing roll <NUM>, which is parallel to the full-length direction T of the cell <NUM>, may be provided to be smaller than the width a of the body <NUM> of the pouch <NUM>, which is parallel to the full-length direction T of the cell <NUM> so that the portion except for the edge of the body <NUM> is pressed.

In addition, each of both the side portions 11d and 12d of the pressing roll <NUM> may be formed to have a gradually smaller diameter toward an end thereof.

Thus, in the electrode assembly <NUM> accommodated in the body <NUM>, a central portion except for the edge in the full-length direction T of the cell <NUM> may be pressed by the central portions 11a and 12a of the pressing roll <NUM>. Thus, the gas disposed in the central portion of the electrode assembly <NUM> may move to the edge of the electrode assembly <NUM> and then be discharged to the outside of the electrode assembly <NUM>. Here, the gas discharged to the outside of the electrode assembly <NUM> may be disposed in the accommodation part <NUM> or the gas pocket part <NUM> inside the pouch <NUM> and then be discharged to the outside of the pouch <NUM> through the degassing process. Here, an outer surface of each of both the side portions 11d and 12d of the pressing roll <NUM> may have a curvature that is rounded from each of the central portions 11a and 12a toward each of the ends. That is, in the pressing roller <NUM>, the curvature may be formed at a corner of each of both the side portions 11d and 12d in the full-width direction W of the cell <NUM>.

Thus, in the electrode assembly <NUM> accommodated in the body <NUM>, a central portion except for the edge in the full-length direction T of the cell <NUM> may be pressed by the central portions 11a and 12a of the pressing roll <NUM>. Thus, the gas disposed in the central portion of the electrode assembly <NUM> may move to the edge of the electrode assembly <NUM> and then be discharged to the outside of the electrode assembly <NUM>. Here, the gas discharged to the outside of the electrode assembly <NUM> may be disposed in the accommodation part <NUM> or the gas pocket part <NUM> inside the pouch <NUM> and then be discharged to the outside of the pouch <NUM> through the degassing process.

The supports <NUM> and <NUM> may support the pressing rolls <NUM>. In addition, the supports <NUM> and <NUM> may support a first roll <NUM> and a second roll <NUM> of the pressing roll <NUM>, respectively. At this time, the support <NUM> supporting the first roll <NUM> may move vertically by a moving means, and thus, the upper portion of the cell <NUM> may be pressed through the first roll <NUM>. Here, the moving means may be, for example, a pneumatic or hydraulic actuator.

A load cell <NUM> may be provided on each of the supports <NUM> and <NUM> to detect a load pressed to the cell <NUM>. Here, for example, the load cell <NUM> may be provided on the support <NUM> supporting the second roll <NUM> disposed below the cell <NUM>.

Hereinafter, an apparatus for manufacturing a secondary battery according to another embodiment of the present invention will be described.

Referring to <FIG>, <FIG>, and <FIG>, an apparatus for manufacturing a secondary battery according to another embodiment of the present invention comprises a pressing roll <NUM> pressing a cell <NUM>, in which an electrode assembly <NUM> and an electrolyte are accommodated in a pouch <NUM>, and a support supporting the pressing roll <NUM>. The pressing roll <NUM> performs roll press on the cell <NUM> in a full-length direction T of the cell <NUM> to manufacture a secondary battery.

The apparatus for manufacturing the electrode assembly according to another embodiment of the present invention is different from the apparatus for manufacturing the electrode assembly according to the foregoing embodiment of the present invention in configuration of the pressing roll <NUM>. Thus, contents of this embodiment, which are duplicated with those according to the forgoing embodiment, will be omitted or briefly described, and also, differences therebetween will be mainly described.

In more detail, in the apparatus for manufacturing the secondary battery according to another embodiment of the present invention, the pressing roll <NUM> may sequentially press the cell <NUM>, in which the electrode assembly <NUM> and the electrolyte are accommodated in the pouch <NUM>, before a degassing process after an activation process to perform roll press.

The pressing roll <NUM> may press a portion except for an edge of the body <NUM> in the pouch <NUM> in the full-width direction W of the cell <NUM>.

Also, a length c of the pressing roll <NUM> may be provided to be smaller than a width a of the body <NUM>.

That is, the length c of the pressing roll <NUM>, which is parallel to the full-length direction T of the cell <NUM>, may be provided to be smaller than the width a of the body <NUM> of the pouch <NUM>, which is parallel to the full-length direction T of the cell <NUM> so that the portion except for the edge of the body <NUM> is pressed.

Thus, the length c of the pressing roll <NUM> may be formed to be smaller by <NUM> or more, which is a lower limit value, than the width a of the body <NUM> to prevent an outer shell of the electrode assembly <NUM> from being damaged. When the electrode assembly <NUM> in which a negative electrode is formed to be larger than a positive electrode is pressed in a stacking direction, the negative electrode may be prevented from being damaged by an edge of the positive electrode. In addition, the length c of the pressing roll <NUM> may be formed to be smaller by <NUM> or less, which an upper limit value, than the width a of the body <NUM> to prevent a gas removal effect at an outer shell-side of the battery from being deteriorated.

The supports <NUM> and <NUM> may support the pressing rolls <NUM>. In addition, the supports <NUM> and <NUM> may support a first roll <NUM> and a second roll <NUM> of the pressing roll <NUM>, respectively. At this time, the support <NUM> supporting the first roll <NUM> may move vertically by a moving means, and thus, the upper portion of the cell <NUM> may be pressed through the first roll <NUM>.

Hereinafter, an apparatus for manufacturing a secondary battery according to further another embodiment of the present invention will be described.

Referring to <FIG>, <FIG>, and <FIG>, an apparatus for manufacturing a secondary battery according to further another embodiment of the present invention comprises a pressing roll <NUM> pressing a cell <NUM>, in which an electrode assembly <NUM> and an electrolyte are accommodated in a pouch <NUM>, and a support supporting the pressing roll <NUM>. The pressing roll <NUM> performs roll press on the cell <NUM> in a full-length direction T of the cell <NUM> to manufacture a secondary battery.

The secondary battery <NUM> according to further another embodiment of the present invention is different from the secondary batteries according to the foregoing embodiments in configuration of the pressing roll <NUM>. Thus, contents of this embodiment, which are duplicated with those according to the forgoing embodiment, will be omitted or briefly described, and also, differences therebetween will be mainly described.

In more detail, in the apparatus for manufacturing the secondary battery according to further another embodiment of the present invention, the pressing roll <NUM> may sequentially press the cell <NUM>, in which the electrode assembly <NUM> and the electrolyte are accommodated in the pouch <NUM>, before a degassing process after an activation process to perform roll press.

In addition, each of both side portions 31d and 32d of the pressing roll <NUM> may be formed to have a diameter that is gradually smaller toward an end thereof. Here, both side portions 31d and 32d of the pressing roll <NUM> may comprise one side portion 31b disposed at one side in the full-width direction W of the cell <NUM> and the other side portion 31c disposed at the other side. At this time, a length d of each of central portions 31a and 32a of the pressing roll <NUM> may be provided to be smaller than a width a of the body <NUM>. Here, the length d of each of the central portions 31a and 32a of the pressure roll <NUM> corresponding to a pressing length for pressing the body <NUM> of the pressure roll <NUM> may be formed, for example, to be smaller by <NUM> to <NUM> than the width a of the body <NUM> in the pouch <NUM>. Furthermore, each of both the side portions 31d and 32d of the pressing roll <NUM> may be chamfered. That is, a corner of an outer circumferential surface of each of both the side portions 31d and 32d of the pressing roll <NUM> may be formed to have an inclined surface having a diameter that is gradually smaller toward an end thereof.

An accommodation process of accommodating an electrode assembly, in which electrodes and separators are alternately stacked, an electrolyte, and one side portion of an electrode lead connected to the electrode, in a pouch to form a cell, an activation process of charging the cell to activate the cell, and a pressing process of sequentially pressing the cell through a pressing roll after the activation process to press the cell were performed to manufacture a secondary battery. Here, in the accommodation process, the other side portion of the electrode lead was accommodated to protrude to the outside of the pouch, and in the pressing process, roll press was performed in a full-length direction of the cell, which is a protrusion direction of the electrode lead.

The same process as in Manufacturing Example <NUM> except that the roll press is performed in a full-width direction of the cell was performed in the pressing process.

The same process as in Manufacturing Example <NUM> except that the pressing process is performed after a degassing process was performed.

<FIG> is a plan view illustrating a state in which a gas within a secondary battery manufactured through a method for manufacturing a secondary battery according to Manufacturing Example <NUM> of the present invention is removed, <FIG> is a plan view illustrating a state in which a gas within a secondary battery manufactured through a method for manufacturing a secondary battery according to Comparative Example <NUM> of the present invention is removed, and <FIG> is a plan view illustrating a state in which a gas within a secondary battery manufactured through a method for manufacturing a secondary battery according to Comparative Example <NUM> of the present invention is removed.

Ultrasonic waves were applied to the secondary battery to measure a residual amount of gas inside the secondary battery through a degree of ultrasonic transmission.

In <FIG>, a region displayed with a red color is an ultrasonic transmission region, and a region displayed with a blue color is an ultrasonic non-transmission region. That is, the region through which the ultrasonic waves are transmittable is a region from which a gas is removed, and the region through which the ultrasonic waves are not transmittable is a region in which an internal gas is disposed.

Referring to <FIG>, in the case of Manufacturing Example <NUM>, a ratio of the ultrasonic non-transmission region was <NUM>%, and referring to <FIG>, a ratio of the ultrasonic non-transmission region in Comparative Example <NUM> was <NUM>%, and referring to <FIG>, a ratio of the ultrasonic non-transmission region in Comparative Example <NUM> was <NUM>%.

Therefore, it is seen that, in the case of Manufacturing Example <NUM>, a ratio of the ultrasonic non-transmission region is <NUM>%, and thus, only a very small amount of internal gas is present, whereas in the case of Comparative Example <NUM>, a ratio of the ultrasonic non-transmission region is <NUM>%, and thus, a significant amount of internal gas is present, and in the case of Comparative Example <NUM>, a ratio of the ultrasonic non-transmission region is <NUM>%, and thus, a significant amount of internal gas is present.

As a result, it is seen that, in the technology of performing the rolling and pressing in the full-length direction of the cell according to Manufacturing Example <NUM>, a residual amount of internal gas is remarkably reduced when compared to the technology of performing the rolling in the full-width direction of the cell according to Comparative Example <NUM>.

Claim 1:
A method for manufacturing a secondary battery, the method comprising:
an accommodation process of accommodating an electrode assembly (<NUM>), in which electrodes and separators are alternately stacked, an electrolyte, and one side portion of electrode leads (<NUM>, <NUM>) connected to the electrodes, in a pouch (<NUM>) to form a cell (<NUM>);
an activation process of charging the cell (<NUM>) to activate the cell (<NUM>);
a pressing process of sequentially pressing the cell (<NUM>) through pressing rolls (<NUM>, <NUM>, <NUM>) after the activation process to roll press the cell (<NUM>); and
a degassing process of discharging an internal gas of the cell (<NUM>) to the outside after the pressing process,
characterized in that, in the pressing process, a body (<NUM>) of the pouch (<NUM>), in which the electrode assembly (<NUM>) is accommodated, is pressed so that a portion except for an edge of the body (<NUM>) is pressed.