Patent Description:
Such a secondary battery is configured so that an electrode assembly is embedded in a battery case (for example, a pouch, a can, and the like). The electrode assembly mounted in the battery case is repeatedly chargeable and dischargeable because of a structure in which a positive electrode/a separator/a negative electrode are repeatedly stacked. The electrode assembly is manufactured in various manners. However, generally, the electrode assembly may be manufactured in a manner in which, after a unit cell is prepared in advance, a plurality of unit cells are stacked to manufacture the electrode assembly.

The process of manufacturing the unit cell comprises a laminating process for bonding a separator to an electrode. In the laminating process, a negative electrode, a separator, and a positive electrode, each of which is wound in the form of a roll, are continuously unwound to be supplied. Here, two or more separators are normally supplied continuously, and the positive electrode and the negative electrode are supplied to be stacked between the separators and on the uppermost separators. That is, each of the positive electrode and the negative electrode is cut by a predetermined size and then put so that the positive electrodes and the negative electrodes are alternately stacked with the separators therebetween.

Also, the separators are continuously connected to each other to pass through the laminating device in the state in which the positive electrode and the negative electrode are alternately stacked between the separators. In the laminating device, heat and a pressure are applied to bond the positive electrode, the separator, and the negative electrode to each other. Also, after passing through the laminating device, the separator is cut to be manufactured into individual unit cells.

Here, the laminating device comprises a pressing roll device in which the positive electrode, the separator, and the negative electrode pass between two rolls and thus are pressed.

Referring to <FIG> that illustrates a state (a) in which an upper roll and a lower roll contact each other and a state (b) in which the upper roll and the lower roll are spaced apart from each other in the pressing roll device according to the related art, the pressing roll device according to the related art comprises an upper roll 2a and a lower roll 1a, which are disposed vertically when a positive electrode, a separator, and a negative electrode pass through the pressing roll device in a state of being stacked. The lower roll 1a is rotatably mounted on a lower mount <NUM>, and the upper roll 2a is rotatably mounted on an upper mount <NUM>. Here, the lower mount <NUM> is fixed in movement, but the upper mount <NUM> is connected to a motor <NUM> through a bracket <NUM> and a screw <NUM> to ascend and descend according to a rotation direction of the motor <NUM>.

However, in such a structure, it is difficult to maintain a constant distance between the upper roll 2a and the lower roll 1a due to vibration (and an impact) generated by mechanical devices during the laminating process. In addition, when deviation in thickness occurs, there is a risk of damage or deformation due to an excessive pressure applied to the positive electrode and the negative electrode, which are stacked.

In order to solve the above problems, if the upper roll 2a and the lower roll 1a are spaced too far apart from each other, a pressure for the pressing is reduced to deteriorate bonding force.

Further prior art is described in <CIT>, <CIT> and <CIT>.

Therefore, a main object of the present invention is to provide a pressing roll device which is capable of solving or at least improving the above problems that may occur in the pressing roll device according to the related art.

A pressing roll device, in which a unit cell passes between an upper roll and a lower roll, according to the present invention which is given precisely in the claims, for achieving the above object comprises:
the lower roll; the upper roll; a lower mount on which the lower roll is mounted and which is fixed in movement; an upper mount on which the upper roll is mounted and which is restricted by a bracket so as to ascend and descend by the bracket; and a stopper disposed between the lower mount and the upper mount so that the lower roll and the upper roll are spaced apart from each other, wherein a damping member that buffers an impact when the upper mount is seated is mounted on the stopper, wherein the stopper has a bar shape that is vertically erected from the lower mount and is expandable and contractible in a longitudinal direction to adjust a spaced distance between the lower mount and the upper mount.

Here, the upper mount may comprise a head part protruding from a top surface of the upper mount, the head part may comprise a body portion protruding vertically from the top surface of the upper mount and an expansion portion of which a diameter increases at an upper end of the body portion, and the head part may be coupled so that separation of the expansion portion is restricted by a clamping portion of the bracket, wherein, in a state in which the bracket is fixed, the upper mount may ascend and descend in the state in which the head part is restricted within a range in which a bottom surface of the clamping portion contacts the top surface of the upper mount, or a top surface of the clamping portion contacts the expansion portion.

When the upper mount is seated on the stopper, a gap may occur between the clamping portion and the expansion portion and between the clamping portion and the top surface of the upper mount.

The bracket may be connected to a motor to ascend and descend according to a rotation direction of the motor.

The stopper may comprise: a fixed part fixedly disposed on the lower mount; and a sliding part that is slidable to ascend and descend in the longitudinal direction from the fixed part.

In the present invention which is precisely given in the claims, having the configuration as described above, the stopper that is capable of ascending and descending is disposed between the lower mount and the upper mount to more easily and reliably maintain the distance between the upper roll and the lower roll, and the stopper is adjustable in length to adjust the distance between the upper roll and the lower roll.

Here, when the upper mount is seated on the stopper, the upper mount may be seated so that the gap occurs between the clamping portion and the expansion portion and between the clamping portion and the top surface of the upper mount. Thus, the stopper supports only the loads of the upper mount and the upper roll to minimize the damage of the electrode when the electrode passes therethrough. That is, in the structure according to the related art, the fixing force between the upper mount and the motor may act as the pressure on the electrode. However, in the present invention, the initial pressure applied to the electrode may be lowered, and if necessary, the pressure transmitted by the motor may be added.

Also, the damping member that buffers the impact when the upper mount is seated may be mounted on the stopper to prevent the durability from being deteriorated due to the impact.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings in such a manner that the technical idea of the present invention may easily be carried out by a person with ordinary skill in the art to which the invention pertains.

The present invention relates to a pressing roll device, which is provided in a laminating device for manufacturing a unit cell so that the unit cell passes between an upper roll and a lower roll. Hereinafter, an embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

The present invention provides a pressing roll device for passing a unit cell between an upper roll <NUM> and a lower roll <NUM> as an embodiment.

<FIG> is a view illustrating a state in which an upper mount <NUM> descends to the lowermost side in a pressing roller device according to the present invention, and <FIG> is a view illustrating a state in which the upper mount <NUM> ascends in <FIG>.

Referring to <FIG> and <FIG>, the pressing roll device of the present invention comprises an upper mount <NUM> and a lower mount <NUM> to which an upper roll <NUM> and a lower roll <NUM> are coupled, respectively.

Each of the upper roll <NUM> and the lower roll <NUM> is made of a material having stiffness that is enough to apply an appropriate pressure to an electrode and a separator and has a cylindrical shape. Also, the upper mount <NUM> and the lower mount <NUM> are mounted so that the upper roll <NUM> and the lower roll <NUM> are rotatable at centers of both surfaces of the upper and lower mounts <NUM> and <NUM>, respectively.

That is, the lower mount <NUM> is fixed in movement so that the lower roll <NUM> is mounted to be rotatable. On the other hand, likewise, the upper roll <NUM> is mounted on the upper mount <NUM> so as to be rotatable. Here, the upper mount <NUM> is restricted in behavior and separation by a bracket <NUM> and also may ascend and descend by the bracket <NUM>.

Also, a stopper <NUM> is disposed between the lower mount <NUM> and the upper mount <NUM> so that the lower roll <NUM> and the upper roll <NUM> are spaced apart from each other.

In the present invention, a head part <NUM> protrudes from a top surface of the upper mount <NUM>. The head part <NUM> comprises a body portion <NUM> protruding vertically from the top surface of the upper mount <NUM> and an expansion portion <NUM> of which a diameter increases at an upper end of the body portion <NUM>. Also, the bracket <NUM> is provided with a clamping portion <NUM> facing a lower side, and the head part <NUM> is coupled so that the separation of the expansion portion <NUM> is restricted by the clamping portion <NUM> of the bracket <NUM>. As illustrated in the drawings, the bracket <NUM> has a space in which the head part <NUM> is accommodated, and the clamping portion <NUM> supports the head part <NUM> so that the head part <NUM> is not separated downward when the head part <NUM> enters the space.

Here, in a state in which the bracket <NUM> is fixed, the upper mount <NUM> may ascend and descend in the state in which the head part <NUM> is restricted within a range in which a bottom surface of the clamping portion <NUM> contacts the top surface of the upper mount <NUM>, or a top surface of the clamping portion <NUM> contacts the expansion portion <NUM>. That is, the range of the ascending and descending is proportional to a length of the body portion <NUM>.

When the upper mount <NUM> is seated on the stopper <NUM> according to the length of the stopper <NUM> in the state in which the height of the bracket <NUM> is fixed, the clamping portion <NUM> is disposed so that a gap occurs between the clamping portion <NUM> and the expansion portion <NUM> and between the clamping portion <NUM> and the top surface of the upper mount <NUM>.

That is, in the case of the above arrangement, when the electrode and the separator pass through the upper roll <NUM> and the lower roll <NUM>, only weights of the upper roll <NUM> and the upper mount <NUM> act as a pressure. Also, when the bracket <NUM> descends to allow the clamping portion <NUM> to press the top surface of the upper mount <NUM>, force transmitted through the bracket <NUM> is further added to act as a pressure on the electrode and the separator.

The bracket <NUM> is configured to ascend and descend by the motor <NUM>. The motor <NUM> and the bracket <NUM> are connected to each other through a screw <NUM> that converts rotational force of the motor <NUM> into an ascending and descending motion of the bracket <NUM>. Thus, the bracket <NUM> ascends and descends according to the rotation direction of the motor <NUM>. For reference, instead of the motor <NUM>, the bracket <NUM> may be configured to ascend and descend by a pneumatic or hydraulic pressure. However, it is preferable that the bracket <NUM> is configured to ascend and descend by the rotation of the motor <NUM> so as to more precisely and quickly control a rotation rate.

Furthermore, when the upper mount <NUM> is seated on the stopper <NUM>, a damping member <NUM> is mounted on the stopper <NUM> so as to suppress an occurrence of impact noise and improve mechanical durability. That is, as illustrated in <FIG>, which illustrates a state in which the damping member <NUM> is mounted on an upper end of the stopper <NUM>, the damping member <NUM> for buffering an impact is additionally provided at one or more ends of the upper end and the lower end of the stopper <NUM>.

Also, in the present invention, the stopper <NUM> may be expanded and contracted in a longitudinal direction to adjust a distance between the upper mount <NUM> and the lower mount <NUM>. That is, as illustrated in <FIG>, which illustrates a state in which the stopper <NUM> increases in length due to the ascending of a sliding part <NUM> from the fixed part <NUM> of the stopper <NUM>, the stopper <NUM> of the present invention may comprise a fixed part <NUM> and a sliding part <NUM>.

The fixed part <NUM> has a bar shape that is vertically erected from the lower mount <NUM> and is fixedly coupled to the lower mount <NUM>. Also, the sliding part <NUM> is configured to be slidable so as to ascend and descend in the longitudinal direction from the fixed part <NUM>. The sliding part <NUM> and the fixed part <NUM> may be configured so that the sliding part <NUM> ascends and descends by injecting compressed air into an inner space between the sliding part <NUM> and the fixed part <NUM> or by mounting a rack gear and a pinion gear in the inner space to allow the rack gear and the pinion gear to rotate by a motor.

In the pressing roll device of the present invention having the above configuration, as illustrated in <FIG>, in which the pressing roll device (left) according to the related art and the pressing roll device (right ) according to the present invention are compared, when an unit cell U passes through the upper roll <NUM> and the lower roll <NUM>, a clearance in which the upper mount <NUM> is capable of ascending may be provided to prevent an electrode provided in the unit cell U from being damaged and separated from its regular position.

In a pressing method for pressing a unit cell U by allowing the unit cell U to pass between an upper roll <NUM> and a lower roll <NUM>. The pressing method comprises a step of allowing the unit cell U to pass between the lower roll <NUM> mounted on a lower mount <NUM> that is fixed in movement and the upper roll <NUM> mounted on an upper mount <NUM> which is capable of ascending and descending in a state in which separation from the bracket <NUM> is restricted.

Here, when the unit cell U passes between the upper roll <NUM> and the lower roll <NUM>, the upper roll <NUM> and the lower roll <NUM> are spaced a predetermined distance from each other. That is, in the method according to the related art, the upper roll and the lower roll may contact each other, and when the electrode of the unit cell passes, a load is concentrated into edge portions of the negative electrode and the positive electrode, which are stacked in the unit cell, to cause the damage of the positive electrode and the negative electrode or the separation of each of the positive electrode and the negative electrode from the seated position thereof. However, here, since the upper roll <NUM> and the lower roll <NUM> are spaced apart from each other, an amount of impact that is initially applied to the negative electrode and the positive electrode may be reduced.

Here, since the upper mount <NUM> is restricted by the bracket <NUM> and capable of ascending and descending within a predetermined range (by a gap occurring between the clamping portion and the expansion portion and between the clamping portion and the top surface of the upper mount), the pressure applied to the unit cell acts as self-weight of each of the upper mount <NUM> and the upper roll <NUM>.

When the unit cell having a predetermined thickness passes between the upper roll <NUM> and the lower roll <NUM>, only the self-weights of the upper mount <NUM> and the upper roll <NUM> may act as the pressure applied to the unit cell. If the unit cell having a thickness greater than the predetermined thickness passes between the upper roll <NUM> and the lower roll <NUM>, force applied from the bracket <NUM> in addition to the self-weights of the upper mount <NUM> and the upper roll <NUM> may be added to act as the pressure applied to the unit cell.

Therefore, there is a step of mounting a stopper <NUM> between the lower mount <NUM> and the upper mount <NUM> before the unit cell passes therethrough so that the lower roll <NUM> and the upper roll <NUM> are spaced apart from each other.

Having the configuration as described above, the stopper <NUM> that is capable of ascending and descending may be disposed between the lower mount <NUM> and the upper mount <NUM> to more easily and reliably maintain the distance between the upper roll <NUM> and the lower roll <NUM>, and the stopper <NUM> may be adjustable in length to adjust the distance between the upper roll <NUM> and the lower roll <NUM>.

Here, when the upper mount <NUM> is seated on the stopper <NUM>, the upper mount <NUM> is seated so that the gap occurs between the clamping portion <NUM> and the expansion portion <NUM> and between the clamping portion <NUM> and the top surface of the upper mount <NUM>. Thus, the stopper <NUM> supports only the loads of the upper mount <NUM> and the upper roll <NUM> to minimize the damage of the electrode when the electrode passes therethrough. That is, in the structure according to the related art, the fixing force between the upper mount and the motor acts as the pressure on the electrode. However, in the present invention, the initial pressure applied to the electrode is lowered, and if necessary, the pressure transmitted to the motor may be added.

Claim 1:
A pressing roll device for laminating unit cells (U), in which a unit cell (U) passes between an upper roll (<NUM>) and a lower roll (<NUM>), the pressing roll device comprising:
the lower roll (<NUM>);
the upper roll (<NUM>);
a lower mount (<NUM>) on which the lower roll (<NUM>) is mounted and which is fixed in movement;
an upper mount (<NUM>) on which the upper roll (<NUM>) is mounted and which is restricted by a bracket (<NUM>) so as to ascend and descend by the bracket (<NUM>); and
a stopper (<NUM>) disposed between the lower mount (<NUM>) and the upper mount (<NUM>) so that the lower roll (<NUM>) and the upper roll (<NUM>) are spaced apart from each other,
characterized in that a damping member (<NUM>) that buffers an impact when the upper mount (<NUM>) is seated is mounted on the stopper (<NUM>),
wherein the stopper (<NUM>) has a bar shape that is vertically erected from the lower mount (<NUM>) and is expandable and contractible in a longitudinal direction to adjust a spaced distance between the lower mount (<NUM>) and the upper mount (<NUM>).