Secondary battery manufacturing system for forming electrode assembly using unit cells manufactured by laminating

Provided is a secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating, and the secondary battery manufacturing system includes: a unit cell forming device for forming unit cells, in which a separator, an anode cell, a separator, a cathode cell, and a separator are stacked in order, from a separator roll, an anode cell roll, and a cathode cell roll, which are rolled; an inverting device for forming inverted unit cells, in which a separator, a cathode cell, a separator, an anode cell, and a separator are stacked in order, by inverting some of two or more unit cells formed by the unit cell forming device; and a stacking device for stacking a unit cell, an anode cell, an inverted unit cell, and a cathode cell in order, in which the process of manufacturing an electrode assembly is simplified, and the defect rate of the manufactured electrode assembly is lowered.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating, and more specifically, to a secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating which alternately stacks unit cells and inverted unit cells.

Background of the Related Art

Rechargeable secondary batteries are widely used as an energy source of a mobile device. In addition, the secondary batteries are used as an energy storage means of an electric vehicle or the like, which is proposed as a solution for solving the problem of exhaustion gas of internal combustion engines and the problem of fossil fuel depletion.

The secondary batteries are classified into a cylindrical cell, a prismatic cell, and a pouch cell according to external and internal structural features.

An electrode assembly of a structure including a cathode, a separator, and an anode constituting a secondary battery is largely classified as a jelly-roll type (rolling type) or a stack type (stacking type) according to its structure. The jelly-roll type electrode assembly is manufactured by coating, drying and pressing an electrode active material or the like on a metal foil used as a current collector, tailoring the metal foil in the form of a band having a desired width and length, separating the anode from the cathode using a separator, and rolling the metal foil in a spiral form.

Although a jelly-roll type electrode assembly may be preferably used in a cylindrical battery, when it is applied to a prismatic or pouch type battery, the electrode active material is peeled off as the stress is locally concentrated, or deformation of the battery is induced due to the contraction and expansion phenomenon repeated in the charge and discharge process.

On the other hand, a stack type electrode assembly is a structure sequentially stacking a plurality of cathode and anode unit cells, and has an advantage of easily obtaining a prismatic shape. However, it is a disadvantage in that the manufacturing process is complicated, and when an impact is applied, the electrode is pushed, and a short circuit occurs.

To solve this problem, some of prior art techniques have proposed a stack and folding type electrode assembly, which has a structure folding a full cell having a structure of a cathode, a separator and an anode or a bicell having a structure of a cathode (anode), a separator, an anode (cathode), a separator, and a cathode (anode) using a long continuous separation film, as a hybrid electrode assembly combining the jelly-roll type and stack type electrode assemblies.

However, the stack and folding type electrode assembly is disadvantageous in that an internal space or system for the manufacturing process of arranging unit cells in a long sheet-type separator one by one and folding the unit cells and the separator by holding both ends are essentially required, and the process is very complicated, and as a result, the facility investment cost is high. Furthermore, as the number of unit cells increases, the unit cells are difficult to roll as they are arranged in a row, and thus, the defect rate of the electrode assembly may increase.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating, which can simplify the process of manufacturing the electrode assembly, and lower the defect rates of the unit cells manufactured by laminating and the electrode assembly formed of the unit cells.

To accomplish the above object, according to one aspect of the present invention, there is provided a secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating, the system comprising: a unit cell forming device for forming unit cells, in which a separator, an anode cell, a separator, a cathode cell, and a separator are stacked in order, from a separator roll, an anode cell roll, and a cathode cell roll, which are rolled; an inverting device for forming inverted unit cells, in which a separator, a cathode cell, a separator, an anode cell, and a separator are stacked in order, by inverting some of two or more unit cells formed by the unit cell forming device; and a stacking device for stacking a unit cell, an anode cell, an inverted unit cell, and a cathode cell in order.

In addition, the unit cell forming device may include: guides for guiding the separator, the anode cell and the cathode cell unrolled from the separator roll, the anode cell roll, and the cathode cell roll to be overlapped; an anode cell cutter for forming unit anode cells by dividing the anode cell in a unit size, and cutting the anode cell to be arranged at appropriate intervals; a cathode cell cutter for forming unit cathode cells by dividing the cathode cell in a unit size, and cutting the cathode cell to be arranged at appropriate intervals; a laminator for stacking and integrating the separator, the unit anode cells arranged at regular intervals, the separator, the unit cathode cells arranged at regular intervals, and the separator in order; and a unit cell cutter for cutting the separator, the unit anode cells arranged at regular intervals, the separator, the unit cathode cells arranged at regular intervals, and the separator integrated by the laminator in a unit cell size.

In addition, an idle roller for guiding the integrated separator, unit anode cells arranged at regular intervals, separator, unit cathode cells arranged at regular intervals, and separator from the laminator to the unit cell cutter may be located between the laminator and the unit cell cutter.

In addition, the inverting device may include: a conveyor belt continuously supplied with the unit cells; an adhesion drum located on the top surface of the conveyor belt to adhere to the unit cells; a table located at one side on the top of the adhesion drum to receive the unit cells from the adhesion drum in an inverted state; and an upper carrier for receiving and moving the inverted unit cells from the table to magazines.

In addition, a suction unit having one or more suction holes formed in the longitudinal direction parallel to the rotation shaft of the adhesion drum may be formed on the circumferential surface of the adhesion drum.

In addition, the table may be provided with a block for limiting the position of the unit cell on the top surface of the table as the block contacts with an end portion of the unit cell.

In addition, the upper carrier may include: a body unit parallel to the rotation shaft of the adhesion drum and located on the table to reciprocate in the longitudinal direction; and a first adhesion unit and a second adhesion unit disposed on both longitudinal sides of the body unit.

In addition, when the body unit reciprocates in the longitudinal direction, any one of the first adhesion unit and the second adhesion unit may adhere to the inverted unit cell positioned on the table, and another one of the first adhesion unit and the second adhesion unit may transfer the inverted unit cell to the magazine.

In addition, the stacking device may include: a floor for preparing the unit cell at a first position, the anode cell at a second position to face the unit cell, the inverted unit cell at a third position, and the cathode cell at a fourth position to face the inverted unit cell; a stage reciprocating between the unit cell and the anode cell and between the inverted unit cell and the cathode cell; and one or more robot arms for stacking a unit cell, an anode cell, an inverted unit cell, and a cathode cell prepared at the first position to the fourth position in order on the stage.

In addition, the stage can be alternately tilted at a predetermined angle toward the first position, the second position, the third position, and the fourth position.

In addition, the first position and the third position may be located on one side of a path along which the stage moves, and the second position and the fourth position may be located on the other side of the path along which the stage moves.

In addition, the robot arms may be positioned between the first position and the third position and between the second position and the fourth position, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereafter, a secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating according to an embodiment of the invention will be described with reference to the accompanying drawings.

As shown inFIG. 1, a secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating according to an embodiment of the present invention includes: a unit cell forming device1000for forming unit cells U1, in which a separator, an anode cell, a separator, a cathode cell, and a separator are stacked in order, from a separator roll R1, an anode cell roll R2, and a cathode cell roll R3, which are rolled; an inverting device2000for forming inverted unit cells U2, in which a separator, a cathode cell, a separator, an anode cell, and a separator are stacked in order, by inverting some of two or more unit cells U1formed by the unit cell forming device1000; and a stacking device3000for stacking a unit cell, an anode cell, an inverted unit cell, and a cathode cell in order.

The unit cell U1has a structure of a unit full cell formed of a separator, an anode cell, a separator, a cathode cell, and a separator. The anode cell is an electrode having a negative polarity, coated with an anode material on both sides, and the cathode cell is an electrode having a positive polarity, coated with a cathode material on both sides. The inverted unit cell U2has a structure of a unit full cell formed in order of a separator, a cathode cell, a separator, an anode cell, and a separator.

As shown inFIG. 2, the unit cell forming device1000includes: guides1100for guiding the separator, the anode cell and the cathode cell unrolled from the separator roll R1, the anode cell roll R2, and the cathode cell roll R3to be overlapped; an anode cell cutter1200for forming one or more unit anode cells by dividing the anode cell in a unit size, and cutting the anode cell to be arranged at appropriate intervals; a cathode cell cutter1300for forming one or more unit cathode cells by dividing the cathode cell in a unit size, and cutting the cathode cell to be arranged at appropriate intervals; a laminator1400for stacking and integrating the separator, the one or more unit anode cells arranged at regular intervals, the separator, the one or more unit cathode cells arranged at regular intervals, and the separator in order; and a unit cell cutter1500for cutting the separator, the one or more unit anode cells arranged at regular intervals, the separator, the one or more unit cathode cells arranged at regular intervals, and the separator integrated by the laminator1400in a unit cell U1size.

When it is determined that the tension is small as deflection occurs in the separator, the anode cell and the cathode cell unrolled from the separator roll R1, the anode cell roll R2and the cathode cell roll R3, the guides1100compensate for the deflection of the separator, the anode cell and the cathode cell by moving up, down, left and right. A control unit or the like for controlling the operation of various sensors and the guides1000may be provided to sense the deflection.

An adhesive is applied on the surface of the separator. The laminator1400generates heat and pressure to integrate the separator, the one or more unit anode cells arranged at regular intervals, the separator, the one or more unit cathode cells arranged at regular intervals, and the separator.

An idle roller1600for guiding the integrated separator, one or more unit anode cells arranged at regular intervals, separator, one or more unit cathode cells arranged at regular intervals, and separator from the laminator1400to the unit cell cutter1500is located between the laminator1400and the unit cell cutter1500. The unit cell cutter1500cuts gap portions, where a unit anode cell or a cathode cell does not exist, in the vertical direction. The unit cell cutter1500may be provided in a form having blades protruding from the top and the bottom.

As shown inFIG. 3, the inverting device2000includes: a conveyor belt2100continuously supplied with the unit cells U1configuring a full cell; an adhesion drum2200located on the top surface of the conveyor belt2100to adhere to the unit cells U1; a table2300located at one side on the top of the adhesion drum2200to receive the unit cells U1from the adhesion drum2200in an inverted state; and an upper carrier2400for receiving and moving the inverted unit cells U1from the table2300to the magazines M1and M2.

The adhesion drum2200is manufactured in the form of a cylinder. A rotation shaft is located at the center of the adhesion drum2200. The rotation shaft receives rotating force from a gear box located on the side surface of the adhesion drum2200. One or more intake pipes are embedded in the adhesion drum2200. A suction unit2210having one or more suction holes2211formed in the width direction parallel to the rotation shaft of the adhesion drum2200is formed on the circumferential surface of the adhesion drum2200. According to an embodiment, four suction units2210are formed on the circumferential surface of the adhesion drum2200. The four suction units2210are arranged along the circumferential surface of the adhesion drum2200at the intervals of 90 degrees.

According to another embodiment, in addition to the suction unit2210, the adhesion drum2200may be provided with a clamp or a hand for momentarily gripping both longitudinal ends of the unit cell U1. In addition, the adhesion drum2200may be manufactured in the form of a triangular prism or a square prism, not in the form of a cylinder. In particular, the rotation shaft may be eccentric and does not pass through the center of the adhesion drum2200.

Meanwhile, an intake pipe is connected to each suction hole2211or connected to the suction unit2210. One or more intake pipes are connected to a vacuum pump. Valves for adjusting the suction force of the unit cell U1by the suction unit2210are mounted on one or more intake pipes. Operation of the valves is controlled by a control valve. The control valve controls operation of the valves so that the suction unit2210may adhere to the unit cell U1or release adhesion of the unit cell U1by logic, control map, formula or the like prepared in advance. In addition, rubber is applied on the rounded surface of the adhesion drum2200. The unit cell U1is pushed from the adhesion drum2200to the table2300as the unit cell U1is rubbed with the rubber.

The table2300is a plate parallel to the ground. The table2300is provided with a block2310for limiting the position of the unit cell U1on the top surface of the table2300as the block contacts with an end portion of the unit cell U1. The unit cell U1is separated from the table2300and prevented from falling to the conveyor belt2100by the block2310. According to another embodiment, a guide may be provided on the table2300to allow the unit cell U1to be positioned at a right position.

The upper carrier2400includes a body unit2410parallel to the rotation shaft of the adhesion drum2200and located on the table2300to reciprocate in the longitudinal direction, and a first adhesion unit2420and a second adhesion unit2430disposed on both longitudinal sides of the body unit2410.

The body unit2410is manufactured in the form of a beam. A hanging unit of a ‘¬’ shape is provided on the body unit2410, and a roller is provided in the hanging unit. The hanging unit is hung so that the roller is seated on a rail located on the top of the conveyor belt2100. A motor is provided in the roller. The roller is rotated by the motor, and the body unit2410reciprocates in the longitudinal direction. The first adhesion unit2420and the second adhesion unit2430are connected to a vacuum pump. The inverted unit cells U1are adhered by the suction force generated by the vacuum pump.

According to an embodiment, when the body unit2410reciprocates in the longitudinal direction, any one of the first adhesion unit2420and the second adhesion unit2430adheres to the inverted unit cell U1positioned on the table2300, and another one of the first adhesion unit2420and the second adhesion unit2430transfers the inverted unit cell U1to the magazine M1or M2. That is, the first adhesion unit2420and the second adhesion unit2430sequentially adhere to inverted unit cells U1and sequentially transfer the unit cells U1to the magazines M1and M2. The magazines M1and M2are arranged to be symmetrical to each other with respect to the conveyor belt2100.

According to another embodiment, although the magazines M1and M2are separately disposed with intervention of the conveyor belt2100, the height spaced apart from the ground or the separation distance from the conveyor belt2100may be different from each other.

FIG. 4is a flowchart illustrating the operation of the inverting device2000.FIGS. 5 to 11are views showing the states of continuously inverting unit cells U1according to the flowchart ofFIG. 4.

As shown inFIGS. 4 to 11, the operation of the inverting device2000includes the steps of: arriving at an adhesion position, by any one of one or more unit cells U1carried by the conveyor belt2100; adhering to the unit cell U1arriving at the adhesion position, by the adhesion drum2200; inverting the unit cell U1adhered to the adhesion drum2200while moving from the bottom of the adhesion drum2200close to the conveyor belt2100to the top of the adhesion drum2200close to the upper carrier2400according to rotation of the adhesion drum2200; transferring the unit cell U1from the adhesion drum2200to the table2300while the unit cell U1is inverted; and receiving and transferring the inverted unit cell U1from the table2300to the magazine M1or M2, by the upper carrier2400.

As shown inFIG. 5, any one of the one or more unit cells U1carried by the conveyor belt2100is adhered to the adhesion drum2200through the step of arriving at an adhesion position and the adhering step.

As shown inFIG. 6, at the step of moving and inverting the unit cell U1, the unit cell U1adhered to the adhesion drum2200as the adhesion drum2200rotates is moved from the bottom of the adhesion drum2200to the top of the adhesion drum2200. At this point, another unit cell U1arriving at the adhesion position is adhered to the adhesion drum2200.

As shown inFIGS. 7 and 8, at the step of receiving and transferring the inverted unit cell U1from the table2300to the magazine M1or M2by the upper carrier2400, the upper carrier2400moves in the longitudinal direction, after the first adhesion unit2420provided at one longitudinal side adheres to the inverted unit cell U1, so that the first adhesion unit2420may arrive at the magazine M1or M2. When the first adhesion part2420moves in the longitudinal direction to arrive at the magazine M1or M2, another unit cell U1is inverted while moving from the bottom of the adhesion drum2200to the top of the adhesion drum2200, and is transferred from the adhesion drum2200to the table2300.

As shown inFIG. 9, when the first adhesion unit2420arrives at the magazine M1or M2, the second adhesion unit2430adheres to another unit cell U1that is inverted. After the second adhesion unit2430adheres to s another unit cell U1and the first adhesion unit2420transfers the unit cell U1to the magazine M1or M2, the upper carrier2400moves in the longitudinal direction as shown inFIG. 10so that the second adhesion unit2430may move toward the other magazine M1or M2arranged to be symmetrical to the magazine M1or M2with respect to the conveyor belt2100. At this point, as the adhesion drum2200rotates, another inverted unit cell U1adhered to the adhesion drum2200is inverted while moving from the bottom of the adhesion drum2200to the top of the adhesion drum2200, and is transferred from the adhesion drum2200to the table2300.

As shown inFIG. 11, when the second adhesion unit2430arrives at the other magazine M1or M2, the first adhesion unit2420adheres to another inverted unit cell U1positioned on the table2300.

As described above, the adhesion drum2200repeatedly adheres to and inverts unit cells U1while rotating, and transfers the inverted unit cells U1to the table2300. The upper carrier2400moves the inverted unit cell U1positioned on the table2300to any one of the two magazines M1and M2, and transfers the inverted unit cell U1to one of the magazines M1and M2while repeatedly reciprocating in the longitudinal direction.

Therefore, according to the inverting device2000of an embodiment of the present invention configured as described above, since a unit cell U1adhered to the adhesion drum2200is inverted while moving from the bottom of the adhesion drum2200to the top of the adhesion drum2200, the unit cells U1can be easily inverted.

Particularly, since inverted unit cells U1are successively stacked on the magazines M1and M2, preparation of the inverted unit cells U1for manufacturing a secondary battery is convenient.

As shown inFIG. 12, the stacking device3000includes: a floor3100for preparing a unit cell U1at a first position P1, an anode cell NC at a second position P2to face the unit cell U1, an inverted unit cell U2at a third position P3, and a cathode cell PC at a fourth position P4to face the inverted unit cell U2; a stage3200reciprocating between the unit cell U1and the anode cell NC and between the inverted unit cell U2and the cathode cell PC; and one or more robot arms3300for stacking a unit cell, an anode cell, an inverted unit cell, and a cathode cell prepared at the first position P1to the fourth position P4in order on the stage3200.

The first position P1and the third position P3are located on one side of a path3110along which the stage3200moves, and the second position P2and the fourth position P4are located on the other side of the path3110that is formed on the floor3100so that the stage3200may move.

The path3110is formed on the floor3100in the form of a straight line, a curved line, an ellipse or a circle. The first position P1, the second position P2, the third position P3and the fourth position P4are arranged to be perpendicular to the path3110. As shown inFIG. 12, when the path3110is a straight line, the stage3200reciprocates between the first position P1and the second position P2and between the third position P3and the fourth position P4while moving forward or backward. As shown inFIG. 13, when the path3110is a rotation path of an ellipse or a circle, the first position P1and the second position P2, and the third position P3and the fourth position P4are repeatedly formed, and the stage3200moves only in a specific direction along the circumference.

FIG. 14is an exemplary view showing the stage3200. As shown inFIG. 14, the stage3200is manufactured to be alternately tilted at a predetermined angle toward the first position P1, the second position P2, the third position P3, and the fourth position P4. The stage3200includes a body unit3210moving along the path3110, and a tilting seat unit3212positioned on the top surface of the body unit3210and tilted left or right around a hinge3213parallel to the ground.

A wheel3211driven along the path3110and a driver for rotating the wheel3211are mounted on the body unit3210. The tilting seat unit3212is provided with a guide3214for seating a unit cell U1, an inverted unit cell U2, an anode cell NC and a cathode cell PC at right positions. The tilting seat unit3212is provided with a clamping unit3215for fixing the unit cell U1, the inverted unit cell U2, the anode cell NC, and the cathode cell PC seated on the tilting seat unit3212.

Referring toFIG. 12again, stacking the unit cell U1, the anode cell NC, the inverted unit cell U2, and the cathode cell PC on the stage3200is accomplished by the robot arms3300. The robot arms3300may be disposed at one side of the first position P1, the second position P2, the third position P3and the fourth position P4, respectively. According to another example, the robot arms3300may be disposed between the first position P1and the third position P3and between the second position P2and the fourth position P4, respectively. In this case, the robot arms3300may move any one among the unit cell U1, the anode cell NC, the inverted unit cell U2, and the cathode cell PC to the stage3200while moving between the first position P1and the third position P3and between the second position P2and the fourth position P4. When the path3110is a rotation path, the robot arm3300may be mounted on the stage3200.

According to the secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating according to an embodiment of the present invention configured as described above, the process of manufacturing an electrode assembly is simplified, and the defect rate of the manufactured electrode assembly is lowered.

Particularly, since the unit cells U1are manufactured through a laminating method, manufacturing of the unit cells U1is very easy. In addition, since a method of alternately stacking unit cells U1and electrode cells is applied as a method of forming an electrode assembly, the process of preparing the unit cells U1and the electrode cells is simple, and the frequency of rework can be remarkably reduced as defective electrodes are removed in advance in a corresponding preparation process. In addition, the unit cells U1and the electrode cells can be seated at right positions through the tilted stage3200and the robot arms3300. Ultimately, the defect rate of the electrode assembly can be lowered.

According to the secondary battery manufacturing system for forming an electrode assembly using unit cells manufactured by laminating according to an embodiment of the present invention configured as described above, the process of manufacturing an electrode assembly is simplified, and the defect rate of the manufactured electrode assembly is lowered.

Particularly, since the unit cells are manufactured through a laminating method, manufacturing the unit cells is very easy. In addition, since a method of alternately stacking unit cells and electrode cells is applied as a method of forming an electrode assembly, the process of preparing the unit cells and the electrode cells is simple, and the frequency of rework can be remarkably reduced as defective electrodes are removed in advance in a corresponding preparation process.

In addition, the unit cells and the electrode cells can be seated at right positions through the tilted stage and the robot arms. Ultimately, the defect rate of the electrode assembly can be lowered.