Patent Description:
The present invention relates to an electrode sheet rewinding apparatus including position-changeable idle roller capable of automatically connecting a PET film that is coupled to an electrode sheet to the electrode sheet rewinding apparatus before rewinding the electrode sheet in order to form a roll path.

With technological development of mobile devices, such as smartphones, laptop computers, and digital cameras, and an increase in demand therefor, research on secondary batteries, which are capable of being charged and discharged, has been actively conducted. In addition, secondary batteries, which are energy sources substituting for fossil fuels causing air pollution, have been applied to an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (P-HEV), and an energy storage system (ESS).

There are a lithium secondary battery, a nickelcadmium battery, a nickel-hydride battery, and a nickel-zinc battery as secondary batteries that are widely used at present. In particular, research and development of the lithium secondary battery, which has high operating voltage and high energy density per unit weight, have been actively conducted.

Such a secondary battery includes an electrode assembly configured to have a structure in which electrodes and separators are alternately stacked and a case configured to receive the electrode assembly. The electrode assembly, which is a power generation element configured to have a structure in which a positive electrode and a negative electrode are stacked in the state in which a separator is interposed therebetween, is classified as a jelly-roll type electrode assembly, which is configured to have a structure in which a long sheet type positive electrode plate having an active material applied thereto and a long sheet type negative electrode plate having an active material applied thereto are wound in the state in which a separator is interposed therebetween, or a stacked type electrode assembly, which is configured to have a structure in which a plurality of positive electrode plates having a predetermined size and a plurality of negative electrode plates having a predetermined size are sequentially stacked in the state in which separators are interposed therebetween.

A stacked and folded type electrode assembly, which is configured to have a structure in which mono-cells each having a positive electrode/separator/negative electrode structure having a predetermined unit size or bicells each having a positive electrode (negative electrode)/separator/negative electrode (positive electrode)/separator/positive electrode (negative electrode) structure are folded using a long continuous separation film, has been developed as an electrode assembly having an advanced structure, which is a combination of the jelly-roll type electrode assembly and the stacked type electrode assembly.

In addition, a laminated and stacked type electrode assembly, which is configured to have a structure in which unit cells, in each of which electrodes and separators are laminated with each other in a state of being alternately stacked, are stacked, has also been developed in order to improve processability of a conventional stacked type electrode assembly and to satisfy demand for various kinds of secondary batteries.

The positive electrode used in the electrode assembly is manufactured by applying a mixture of a positive electrode active material, a conductive agent, and a binder to a positive electrode current collector, such as metal foil, and drying the mixture. A filler may be further added to the mixture as needed.

In addition, the negative electrode is manufactured by applying a negative electrode material to a negative electrode current collector and drying the negative electrode material. The components described in connection with the positive electrode may be optionally further included as needed.

After passing through a portion of the electrode manufacturing process, such as a notching process or a drying process, the electrode sheet is stored or transported in a state of being rewound around a bobbin.

The electrode sheet rewound around the bobbin is unwound so as to be used in a subsequent process. At this time, in order to solve a problem in that a portion of the innermost part of the electrode sheet cannot be used, a predetermined length of PET film is wound around the bobbin in the state in which the bobbin is empty before the electrode sheet is rewound therearound.

In the case in which the electrode sheet is not directly rewound around the empty bobbin but is rewound around the empty bobbin in a state of being connected to the PET film, it is possible to remedy a disadvantage in that a portion of the end part of the electrode sheet cannot be used when the electrode sheet wound around the bobbin is unwound.

In order to rewind the electrode sheet using the PET film, however, it is necessary to perform a process of unwinding the PET film from the bobbin before the electrode sheet is rewound to maintain a tangential line to the electrode sheet together with a touch roll located above the bobbin and supplying the PET film to an idle roller configured to enable rewinding of the electrode sheet to be easily performed, thereby forming a roll path.

Conventionally, such a PET film supply process is manually performed by a worker, whereby work efficiency is lowered and foreign matter is generated due to movement of the worker.

The prior art relevant to the present invention is given by <CIT> and <CIT>. It is known from the prior art a hoop material cut by a slitter device into a minor width is held by a press roller and a drive roller, having a speed higher than the feed-in speed of the slitter, and wound on a bobbin in the condition with no slippage. In the case the hoop material is free from slack and elongation, individual winding is made by bobbin having respective slip mechanism in the takeup part while a constant tension is held. In the case any elongation or slack is generated, only the hoop material portion situated in the applicable part of generation is taken up at the takeup speed of the takeup bobbin, and the generated slack or elongation is absorbed within a certain period of time.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an electrode sheet rewinding apparatus configured to have a structure in which the position of an idle roller is changeable by a first driving means and a second driving means such that a PET film that is coupled to an electrode sheet is automatically connected to the electrode sheet rewinding apparatus before rewinding the electrode sheet in order to form a roll path.

In order to accomplish the above object, an electrode sheet rewinding apparatus according to the present invention includes a bobbin having a PET film wound therearound, a bobbin holder configured to hold the bobbin, a base plate located under the bobbin holder, the base plate configured to support the bobbin holder, a roller type touch roll configured to press an electrode sheet rewound around the bobbin above the bobbin to prevent meandering of the electrode sheet, a vertical plate located at one side of the base plate, the touch roll attached to the vertical plate, and an idle roller unit configured to form a tangential line to the electrode sheet rewound around the bobbin together with the touch roll, wherein the idle roller unit includes an idle roller configured to maintain tension of the electrode sheet that is rewound and to form a tangential line to the electrode sheet and a first driving means and a second driving means configured to change the position of the idle roller.

Also, in the electrode sheet rewinding apparatus according to the present invention, the idle roller unit may further include a guide roller configured to maintain the tension of the electrode sheet together with the idle roller.

Also, in the electrode sheet rewinding apparatus according to the present invention, the idle roller unit may further include an upper frame, the first driving means provided above the upper frame, the second driving means being provided under the upper frame.

Also, in the electrode sheet rewinding apparatus according to the present invention, the idle roller unit may further include a lower frame located under the second driving means, the lower frame configured to fix the idle roller unit to the base plate.

Also, in the electrode sheet rewinding apparatus according to the present invention, the first driving means may include a driving shaft, a first gear connected to the driving shaft, and an idle roller support having one side rotatably connected to the driving shaft and the other side connected to the idle roller, whereby the first driving means may be configured to rotate the idle roller from a position perpendicular to a floor to a position parallel to the floor.

Also, in the electrode sheet rewinding apparatus according to the present invention, the upper frame may include a second gear engaged with the first gear, the second gear configured to rotate the first gear.

Also, in the electrode sheet rewinding apparatus according to the present invention, the second driving means may be located between the upper frame and the lower frame to straightly move the idle roller in a direction parallel to the floor.

Also, the electrode sheet rewinding apparatus according to the present invention may further include a PET film sensor.

Also, in the electrode sheet rewinding apparatus according to the present invention, the PET film sensor may be attached to the base plate or the bobbin holder.

In addition, a battery cell may be manufactured using the electrode sheet rewinding apparatus according to the present invention.

In addition, a battery module may include the battery cell.

An electrode sheet rewinding apparatus according to the present invention has an advantage in that the position of an idle roller is changeable through rotation and straight movement thereof, whereby it is possible to automatically form a PET film roll path.

In addition, the electrode sheet rewinding apparatus according to the present invention has an advantage in that the PET film roll path is automatically formed, whereby it is possible to prevent deterioration in work efficiency and generation of foreign matter due to movement of a worker.

Hereinafter, an electrode sheet rewinding apparatus according to the present invention will be described with reference to the accompanying drawings.

<FIG> is a front view schematically showing an electrode sheet rewinding apparatus according to an embodiment of the present invention.

When describing the electrode sheet rewinding apparatus <NUM> according to the present invention in detail with reference to <FIG>, the electrode sheet rewinding apparatus <NUM> includes an idle roller unit <NUM>, a bobbin <NUM>, a bobbin holder <NUM>, a base plate <NUM>, a vertical plate <NUM>, a touch roll <NUM>, and a PET film sensor <NUM>.

First, a predetermined length of PET film P is wound around the bobbin <NUM> in the state in which the bobbin <NUM> is empty before an electrode sheet is rewound therearound.

As previously described, the PET film P is provided in order to use the entirety of the electrode sheet without waste upon unwinding the electrode sheet wound around the bobbin.

Next, the bobbin holder <NUM> is located on the base plate <NUM> to hold the bobbin <NUM>.

In addition, the vertical plate <NUM>, which is upright in a vertical direction in a state of being spaced apart from the bobbin holder <NUM> by a predetermined distance, is located on the base plate <NUM>.

The touch roll <NUM> may be attached to one side of the vertical plate <NUM>.

The touch roll <NUM>, which is configured in the shape of a roller, presses the electrode sheet that is rewound around the bobbin <NUM> above the bobbin <NUM> in order to prevent meandering of the electrode sheet and to prevent introduction of air between electrode sheet layers.

Meanwhile, the PET film sensor <NUM> is coupled to the base plate <NUM> or the bobbin holder <NUM> to sense the position of the PET film P that is unwound from the bobbin <NUM>, thereby providing data necessary to set a movement range of the idle roller unit <NUM>.

A laser sensor, an ultrasonic sensor, or an optical sensor may be used as the PET film sensor <NUM>. However, the present invention is not limited thereto, and any of various known sensors capable of detecting the PET film P may be used.

<FIG> is a perspective view of an idle roller unit according to an embodiment of the present invention.

When describing the position-changeable idle roller unit <NUM> according to the present invention in detail with reference to <FIG>, the idle roller unit <NUM> includes an idle roller <NUM>, a first driving means <NUM>, an upper frame <NUM>, a second driving means <NUM>, a lower frame <NUM>, and a guide roller <NUM>.

First, the idle roller <NUM> contacts the PET film P or the electrode sheet together with the touch roll <NUM> to maintain tension of the PET film P or the electrode sheet and to form a tangential line to the PET film or the electrode sheet such that the electrode sheet can be easily rewound. The idle roller is a roller having a width greater than the width of the electrode sheet or the PET film P.

Next, the first driving means <NUM> includes a driving shaft <NUM>, a first gear <NUM>, and an idle roller support <NUM>.

Here, the idle roller support <NUM> is connected to opposite ends of the driving shaft <NUM>, which extends through the first gear <NUM>. The driving shaft <NUM> is rotated together with the first gear <NUM> when the first gear <NUM> is rotated in order to rotate the idle roller support <NUM> connected thereto from a position perpendicular to the floor to a position parallel to the floor or from the position parallel to the floor to the position perpendicular to the floor.

In addition, one end of the idle roller support <NUM> is connected to the driving shaft, and the other end of the idle roller support is connected to the idle roller <NUM>. Consequently, the idle roller <NUM> is also rotated with rotation of the idle roller support <NUM>, whereby the position of the idle roller <NUM> is changed.

Meanwhile, the upper frame <NUM> includes an upper frame body <NUM> and a second gear <NUM>.

The first driving means <NUM> is fastened to the upper frame body <NUM>, and the second gear <NUM> is engaged with the first gear <NUM> of the first driving means <NUM> in order to drive the first gear <NUM>.

The gear ratio of the first gear <NUM> to the second gear <NUM> and the rotational speed of the second gear <NUM> may be appropriately adjusted to control the position change speed of the idle roller <NUM>.

Next, the second driving means <NUM> is located under the upper frame <NUM>.

The second driving means <NUM>, which is configured to straightly move the upper frame <NUM> in a direction parallel to the floor, may be a combination of a linear motion (LM) guide and a motor. However, the present invention is not limited thereto, and any of various known devices capable of performing straight reciprocation may be used.

The upper frame <NUM> is straightly reciprocated by the second driving means <NUM>, and therefore the first driving means <NUM> coupled to the upper frame <NUM> and the idle roller <NUM> coupled to the first driving means <NUM> may be straightly reciprocated.

Meanwhile, the lower frame <NUM> is coupled to the base plate <NUM>, and second driving means <NUM> is provided on the lower frame <NUM>. The lower frame <NUM> serves to fix and support the idle roller unit <NUM>.

In addition, the guide roller <NUM> may be coupled to one side of the lower frame <NUM>.

The guide roller <NUM> is a roller that serves to maintain tension of the electrode sheet together with the idle roller <NUM>.

<FIG> are schematic views showing a process of automatically connecting the PET film to the electrode sheet rewinding apparatus using the idle roller unit according to the embodiment of the present invention.

When describing a process of automatically connecting the PET film P to the electrode sheet rewinding apparatus to form a roll path for rewinding of the electrode sheet with reference to <FIG>, first, the bobbin <NUM> having only the PET film P wound therearound is mounted to the electrode sheet rewinding apparatus <NUM>.

Subsequently, as shown in (a) of <FIG>, the position of the PET film P is sensed by the PET film sensor <NUM>, and the first driving means <NUM> is driven based on sensed data in order to rotate the idle roller <NUM> so as to be located under the PET film P.

Subsequently, as shown in (b) of <FIG>, the idle roller <NUM> is straightly moved in the direction parallel to the floor using the second driving means <NUM> in order to accurately adjust the position of the idle roller.

Claim 1:
An electrode sheet rewinding apparatus (<NUM>) for rewinding an electrode sheet that has passed through a portion of a secondary battery electrode manufacturing process, the electrode sheet rewinding apparatus (<NUM>) comprising:
a bobbin (<NUM>) having a PET film (P) wound therearound;
a bobbin holder (<NUM>) configured to hold the bobbin (<NUM>);
a base plate (<NUM>) located under the bobbin holder (<NUM>), the base plate configured to support the bobbin holder (<NUM>);
a roller type touch roll (<NUM>) configured to press an electrode sheet rewound around the bobbin (<NUM>) above the bobbin (<NUM>) to prevent meandering of the electrode sheet;
a vertical plate (<NUM>) located at one side of the base plate (<NUM>), the touch roll (<NUM>) attached to the vertical plate; and
an idle roller unit (<NUM>) configured to form a tangential line to the electrode sheet rewound around the bobbin (<NUM>) together with the touch roll (<NUM>), wherein
the idle roller unit (<NUM>) comprises:
an idle roller (<NUM>) configured to maintain tension of the electrode sheet that is rewound and to form a tangential line to the electrode sheet; and
a first driving means (<NUM>) and a second driving means (<NUM>) configured to change a position of the idle roller (<NUM>).