Patent Description:
The present invention relates to an electrode cutting device and an electrode manufacturing apparatus including the same. More particularly, the present invention relates to an electrode cutting device capable of monitoring a gripper configured to fix an electrode sheet, thereby preventing poor electrode cutting, and an electrode manufacturing apparatus including the same.

With acceleration in capacity increase and energy density improvement of a lithium secondary battery, the lithium secondary battery has been used as an energy source for medium and large devices, such as a vehicle or a power storage system, as well as small devices, such as a portable electronic device.

The lithium secondary battery may be manufactured using a method of receiving an electrode assembly, configured to have a structure in which a positive electrode, a separator, and a negative electrode are sequentially stacked, in a battery case and hermetically sealing the battery case.

The electrode assembly includes a single-cell configured to have a structure in which a first electrode and a separator are stacked, a mono-cell configured to have a structure in which a first electrode, a separator, and a second electrode are stacked, and a bi-cell configured to have a structure in which a first electrode, a separator, a second electrode, a separator, and a third electrode are stacked.

Each of the electrodes constituting the electrode assembly is manufactured by applying an electrode mixture to one surface or opposite surfaces of a thin electrode sheet made of copper, aluminum, or nickel, drying the same, pressing the same, and cutting the electrode sheet into a unit electrode.

A positive electrode and a negative electrode, each of which is the unit electrode thus manufactured, are stacked and laminated in the state in which a separator is interposed therebetween, whereby a unit cell is manufactured.

If the positive electrode and the negative electrode are not cut so as to have uniform sizes in a process of cutting the electrode sheet into the unit electrode, peripheries of the positive electrode and the negative electrode stacked in the state in which the separator is interposed therebetween may not be parallel to each other.

In addition, if poor cutting occurs when a certain unit electrode is cut from the electrode sheet, continuous poor electrode cutting may occur. In this case, it is necessary for a worker to interrupt the electrode cutting process and to take a measure for correction of poor cutting.

Such poor cutting may occur when air leaks from a cylinder that drives a gripper configured to fix the electrode sheet, whereby a pressing force of the gripper is reduced. Conventionally, a method of checking air leakage from the cylinder through worker's touch was used.

This method increases dead time during a battery manufacturing process, whereby yield is reduced.

In connection therewith, Patent Document <NUM> discloses an electrode cutting device configured to form an electrode tab, wherein the electrode cutting device includes a first cutting unit and a second cutting unit configured to move while crossing each other in order to cut a tab formation portion.

Patent Document <NUM> discloses that the first cutting unit disposed under the tab formation portion moves upwards, a stripper disposed above the tab formation portion moves downwards so as to come into tight contact with an upper surface of the tab formation portion, and the second cutting unit moves downwards, wherein the cutting units cross each other to form an electrode tab, but does not disclose technology for adjusting the force of the stripper that fixes the electrode tab.

Accordingly, there is a need for technology capable of easily checking the pressing force of a gripper configured to fix an electrode sheet when cutting the electrode sheet into a unit electrode, thereby preventing poor electrode cutting.

(Patent Document <NUM>) <CIT>)
The prior art relevant to the present invention are given by <CIT>, <CIT> and <CIT>.

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 cutting device capable of stably fixing an electrode sheet such that electrodes stacked in a lamination process are aligned with each other and an electrode manufacturing apparatus including the same.

Particular embodiments of the present invention are given by the additional features of the appended dependent claims. An electrode cutting device according to the present invention to accomplish the above object includes a cutting unit configured to cut an electrode sheet and a fixing unit configured to fix the electrode sheet, wherein the cutting unit includes a cutter configured to cut the electrode sheet by shearing and a cutter lifting portion configured to move the cutter so as to be perpendicular to a surface of the electrode sheet, and the fixing unit includes a gripper configured to press the electrode sheet so as to be fixed, a driving portion configured to drive the gripper so as to be moved, and a sensor configured to monitor the driving portion.

In the electrode cutting device according to the present invention, the cutter may have a double-edged structure in which the height of the cutter is gradually increased from the middle to opposite ends thereof in a lateral direction.

In the electrode cutting device according to the present invention, the cutter may include an upper cutter configured to be located above the electrode sheet and a lower cutter configured to be located under the electrode sheet, the lower cutter being configured to cut the electrode sheet while crossing the upper cutter moved downwards.

In the electrode cutting device according to the present invention, the driving portion is driven by a cylinder.

In the electrode cutting device according to the present invention, the width of the gripper may be greater than the width of the electrode sheet.

In the electrode cutting device according to the present invention, a protrusion may be formed on a pressing surface of the gripper.

In the electrode cutting device according to the present invention, a rubber coating layer may be added to the pressing surface of the gripper.

In the electrode cutting device according to the present invention, the sensor is a pneumatic gauge sensor, and the sensor is configured to continuously or periodically monitor the pressure of the cylinder.

In the electrode cutting device according to the present invention, the sensor may be detachably attached to the driving portion.

In addition, the present invention provides an electrode manufacturing apparatus including the electrode cutting device. Specifically, the electrode manufacturing apparatus includes the electrode cutting device, a separator supply unit configured to supply a separator, on which a cut positive electrode and a cut negative electrode is disposed, a lamination device configured to laminate the positive electrode and the negative electrode attached to the separator, a separator cutting unit configured to cut the separator of a laminated stack, and an inspection unit configured to inspect alignment of a unit cell, and the electrode cutting device includes a positive electrode cutting device and a negative electrode cutting device.

In the electrode manufacturing apparatus according to the present invention, when the alignment of the unit cell inspected by the inspection unit is not correct, the pressure of the driving portion may be checked using the sensor of the positive electrode cutting device and the sensor of the negative electrode cutting device.

In addition, the present invention may provide various combinations of the above solving means.

As is apparent from the above description, an electrode cutting device according to the present invention includes a sensor capable of monitoring the pressure of a cylinder, which is a means that drives a gripper configured to fix an electrode sheet, and therefore it is possible to check whether air leaks from the cylinder without worker intervention.

In addition, it is possible to check the pressure of the cylinder in real time using the sensor, whereby it is possible to prevent continuous poor electrode cutting, and therefore it is possible to reduce a defect rate.

In addition, anti-slip treatment is performed on a lower surface of the gripper that is brought into contact with the electrode sheet, whereby it is possible to increase fixing force of the electrode sheet.

<FIG> is a side view of an electrode cutting device according to the present invention, and <FIG> is a perspective view of the electrode cutting device.

Referring to <FIG>, an electrode sheet <NUM> is transferred to an upper surface of a support portion <NUM>, and the electrode sheet <NUM> is fixed by a fixing unit <NUM>, whereby transfer of the electrode sheet is stopped. In this state, the electrode sheet <NUM> is cut by a cutting unit <NUM>, whereby an electrode <NUM> is discharged.

Electrodes <NUM> are disposed on a separator <NUM> so as to be spaced apart from each other.

The electrode cutting device according to the present invention includes a cutting unit <NUM> configured to cut an electrode sheet <NUM> and a fixing unit <NUM> configured to fix the electrode sheet <NUM>.

The cutting unit <NUM> includes a cutter <NUM> configured to cut the electrode sheet <NUM> by shearing while being moved downwards so as to be perpendicular to the electrode sheet and a cutter lifting portion <NUM> configured to move the cutter <NUM> so as to be perpendicular to a surface of the electrode sheet <NUM>.

The fixing unit <NUM> includes a gripper <NUM> configured to press the electrode sheet <NUM> so as to be fixed, a driving portion <NUM> configured to drive the gripper <NUM> so as to be moved, and a sensor <NUM> configured to monitor the driving portion <NUM>.

The gripper <NUM> is moved upwards and downwards so as to be perpendicular to the electrode sheet <NUM>. That is, when the gripper is moved downwards, the electrode sheet <NUM> is fixed onto the support portion <NUM>, and when the gripper <NUM> is moved upwards, the fixed state of the electrode sheet <NUM> is released, and the electrode sheet <NUM> is transferred.

Alternatively, the gripper may be moved upwards and downwards, and at the same time or subsequently may be moved forwards and rearwards in a direction parallel to a transfer direction M of the electrode sheet.

The driving portion <NUM> is driven by a cylinder, and the gripper may be driven by increasing or decreasing the air pressure of the cylinder.

In addition, the cutter lifting portion <NUM> may be driven by increasing or decreasing the air pressure of the cylinder.

The sensor <NUM> may be a pneumatic gauge sensor, and the sensor <NUM> may continuously monitor the pressure of the cylinder. Alternatively, measurement time may be set such that the sensor <NUM> can periodically monitor the pressure of the cylinder.

In general, the cutting unit and the fixing unit are disposed so as to be adjacent to each other, or are integrally assembled with each other. Air may leak from the cylinder due to vibration generated from the cutting unit, whereby the air pressure of the cylinder may be reduced. In this case, the force of the fixing unit applied to the electrode sheet may be lower than a predetermined value, whereby the electrode sheet may not be stably fixed, and therefore the electrode sheet may move in the movement direction thereof.

If the cutting unit cuts the electrode sheet in this state, poor cutting, in which deviation occurs in length of the electrode sheet in the transfer direction M thereof, may occur. As a result, misalignment between electrodes may occur when the electrodes are stacked so as to be laminated.

In addition, poorly cut electrodes may be continuously manufactured as long as the electrode cutting device is not stopped, whereby yield may be reduced.

When such poor cutting occurs, therefore, it is important to rapidly detect the same and to take an appropriate measure.

In the present invention, therefore, the sensor <NUM> configured to measure the air pressure of the driving portion <NUM> may be attached to the driving portion <NUM>, whereby it is possible to rapidly and accurately detect whether the air pressure of the driving portion is changed.

In the present invention, the width a1 of the gripper <NUM> may be greater than the width a2 of the electrode sheet in order to secure stability in fixing the electrode sheet <NUM>.

The driving portion <NUM> is added to each of opposite ends of the gripper <NUM> in a lateral direction so as to evenly press the gripper.

In a concrete example, the sensor <NUM> may be detachably attached to the driving portion <NUM>, and it is possible to check whether a large number of driving portions are defective using a single sensor.

<FIG> is a side view sequentially showing a process of cutting an electrode using the cutter, which includes an upper cutter and a lower cutter.

Referring to <FIG>, a process of cutting the electrode sheet <NUM> using the electrode cutting device, which includes the cutting unit <NUM> and the fixing unit <NUM> including the sensor <NUM>, is shown.

However, the cutter <NUM> shown in <FIG> includes an upper cutter <NUM> located above the electrode sheet <NUM> and a lower cutter <NUM> located under the electrode sheet <NUM>, the lower cutter being configured to cut the electrode sheet <NUM> while crossing the upper cutter <NUM> moved downwards and to discharge an electrode <NUM>.

It is preferable for the distance between the upper cutter <NUM> and the lower cutter <NUM> to be approximately <NUM>. The left surface of the upper cutter <NUM> and the right surface of the lower cutter <NUM> are slid relative thereto, whereby the electrode sheet <NUM> is cut.

<FIG> is a perspective view of the cutter.

Referring to <FIG>, the cutter <NUM>, which is used as an upper cutter, is configured to have a double-edged structure in which the height H of the cutter is gradually increased from the middle to opposite ends thereof in a lateral direction W.

Unlike this, if the height of the cutter is uniform, cutting force is reduced, and it is difficult to achieve parallelism with the lower cutter as the width of the electrode sheet is increased. As shown in <FIG>, therefore, the double-edged structure is used in order to increase cutting force.

<FIG> is a perspective view of the gripper.

Referring to <FIG>, the gripper <NUM> performs a function of stably fixing the electrode sheet. In order to effectively perform this function, a protrusion <NUM> may be formed on a pressing surface of the gripper that is brought into tight contact with the electrode sheet. Alternatively, a rubber coating layer <NUM> may be formed on the pressing surface of the gripper.

<FIG> is a schematic view of an electrode manufacturing apparatus.

Referring to <FIG>, the electrode manufacturing apparatus includes a positive electrode cutting device <NUM> configured to cut a positive electrode sheet in order to discharge a positive electrode, a negative electrode cutting device <NUM> configured to cut a negative electrode sheet in order to discharge a negative electrode, a separator supply unit <NUM> configured to supply a separator <NUM>, on which the cut positive electrode <NUM> and the cut negative electrode <NUM> is disposed, a lamination device <NUM> configured to laminate the positive electrode and the negative electrode attached to the separator, a separator cutting unit <NUM> configured to cut the separator of the laminated stack, and an inspection unit <NUM> configured to inspect alignment of a unit cell <NUM>.

The positive electrode cutting device <NUM> and the negative electrode cutting device <NUM> include sensors <NUM> and <NUM> configured to monitor the pressure of grippers <NUM> and <NUM>, respectively. When the positive electrode and the negative electrode of the unit cell <NUM> inspected by the inspection unit <NUM> are misaligned, the pressure of the driving portion may be checked using the sensor <NUM> of the positive electrode cutting device <NUM> and the sensor <NUM> of the negative electrode cutting device <NUM>.

If the pressure of the driving portion deviates from a predetermined range, an electrode manufacturing process may be immediately interrupted in order to stop production of defective electrodes.

In the present invention, as described above, the sensor configured to monitor the pressure of the cylinder, which drives the gripper, is included such that the electrode sheet is cut in the state in which the electrode sheet is stably fixed, whereby it is possible to rapidly and accurately check whether defective electrodes are produced without worker intervention.

Claim 1:
An electrode cutting device (<NUM>, <NUM>) comprising:
a cutting unit (<NUM>) configured to cut an electrode sheet (<NUM>); and
a fixing unit (<NUM>) configured to fix the electrode sheet (<NUM>), wherein the cutting unit (<NUM>) comprises:
a cutter (<NUM>, <NUM>) configured to cut the electrode sheet (<NUM>) by shearing; and
a cutter lifting portion (<NUM>) configured to move the cutter (<NUM>, <NUM>) so as to be perpendicular to a surface of the electrode sheet (<NUM>), and
wherein the fixing unit (<NUM>) comprises:
a gripper (<NUM>, <NUM>, <NUM>) configured to press the electrode sheet (<NUM>) so as to be fixed; and
a driving portion (<NUM>) configured to drive the gripper (<NUM>, <NUM>, <NUM>) so as to be moved, wherein the driving portion (<NUM>) is driven by a cylinder;
characterized in that the fixing unit comprises
a sensor (<NUM>, <NUM>, <NUM>) configured to monitor the driving portion (<NUM>), wherein the sensor (<NUM>, <NUM>, <NUM>) is a pneumatic gauge sensor, and wherein the sensor (<NUM>, <NUM>, <NUM>) is configured to continuously or periodically monitor a pressure of the cylinder.