Patent Description:
Secondary batteries refer to batteries that are chargeable and dischargeable unlike primary batteries that are not chargeable. Such a secondary battery is widely used not only for portable devices such as a mobile phone, a notebook, and a camcorder but also for transportation such as an electric vehicle. As a result, the secondary battery is gradually expanding in a range of application.

In general, the secondary battery has a structure comprising an electrode assembly having a structure in which electrodes (a negative electrode and a positive electrode) and a separator are alternately stacked, an electrolyte allowing ions to move to the electrodes, and a case in which the electrode assembly and the electrolyte are accommodated. The electrode assembly is manufactured so that the positive electrode, the negative electrode, and the separator are alternately stacked to form a plurality of layers.

Also, a process of manufacturing the secondary battery is largely classified into an electrode plate process of manufacturing a positive electrode plate and a negative electrode plate, an assembly process of inserting an electrode together with an electrolyte into a case after the electrode assembly is manufactured by using the positive electrode plate and the negative electrode plate, and a formation process of activating movement of ions of the electrode assembly. Each of the electrode plate process, the assembly process, and the formation process is divided into detailed processes.

Here, the electrode plate process comprises a mixing process of mixing a conductive material and a binder into an active material, a coating process of applying the mixed active material on a collector, a press process of pressing the active material onto a surface of the collector, and a process of shearing the electrode so that the electrode in which the active material adheres to the surface of the collector is cut to a proper size to form an electrode tab. Here, a slitting process for cutting the electrode (with the active material applied on the surface of the collector) to the proper size and a notching process of shearing the electrode to form the electrode tab may be performed sequentially or simultaneously.

Although the notching process belongs to the electrode plate process or the assembly process, the notching process may comprise a processing process of shearing the electrode into a predetermined pattern, but a separate drying process is required. Since a lamination process of continuously bonding the electrode to the separator is performed after the processing process, the drying process is necessarily required to dry the moisture that remains on the surface of the electrode to interfere with the bonding.

However, the drying process according to the related art is performed in a manner in which the notched electrode manually moves and is stored and then is put into a vacuum drying device (a vacuum dryer (VD)) in a unit of a certain quantity, and hot air is blown in a state in which a negative pressure is applied to dry the moisture.

However, the drying method has a problem that it takes a considerable time for the movement and storage of the electrode. This problem has become a main cause of delay of an entire production process time as a production amount of products increases. <CIT> and <CIT> disclose a notching apparatus.

Thus, to solve the conventional problem in which the processing process and the drying process of the notching process are individually performed to increase in process time, a main object of the present invention is to provide a notching apparatus and method for a secondary battery, in which a process time is reduced, and drying is performed through infrared radiation instead of hot air to improve drying efficiency and reduce a defect occurrence rate.

To achieve the above object, the present invention is defined in the appended set of claims and comprises: a notching unit shearing an electrode that is continuously supplied; a drying unit drying the electrode while the electrode discharged from the notching unit passes therethrough; and a collecting unit of collecting the electrode discharged from the drying unit, wherein the drying unit comprises a heating body provided with a drying space that is a passage, through which the electrode passes, therein and lamp parts mounted on the heating body to irradiate infrared rays onto a surface of the electrode while the electrode moves through the drying space.

Each of the lamp parts according to the present invention comprises: a housing of which a side facing the electrode is opened and which is fixed and mounted on the drying unit; a heating lamp mounted on the housing to generate the infrared rays according to applying of power; and a reflection plate mounted on the housing to reflect the infrared ray irradiated from the heating lamp to the opened side of the housing.

Also, the heating lamp may have a straight shape and is mounted in parallel to a longitudinal direction of the housing or may have a bulb shape according to a process or a design of the apparatus. Also, the reflection plate may have a concave shape to reflect the infrared rays irradiated by the heating lamp to the opened side.

According to the present invention, the electrode may have a structure in which an active material is applied to a surface of a collector made of a metal material, and the infrared rays irradiated from the heating lamp may have a wavelength in which an absorption rate of the infrared rays into the active material is higher than that of the infrared rays into the collector. That is, the irradiated infrared rays may be reflected by the collector and absorbed into the active material.

The lamp parts facing each other are continuously disposed or disposed with an interval therebetween, and spaces between the lamp parts facing each other are connected to each other to form the drying space.

The drying space has a horizontal section formed in a horizontal direction and a vertical section formed in a vertical direction within the drying unit. A transfer roller for switching a transfer direction may be disposed at a portion at which the electrode is switched between the horizontal section and the vertical section.

Furthermore, an auxiliary frame having a vertical surface of which both side surfaces are vertically erected and a horizontal top surface may be built in the heating body, and a portion of the lamp parts may be mounted on the vertical surface and the horizontal surface of the auxiliary frame, wherein the vertical section of the drying space may be formed at a position at which the electrode passes through the vertical surface of the auxiliary frame, and the horizontal section may be formed at a position at which the electrode passes through the horizontal surface of the auxiliary frame.

Also, the collecting unit may comprise a collecting roller winding the electrode so as to be wound therearound, and an exhaust device for discharging moisture evaporated in the heating body to the outside may be mounted in the heating body.

The present invention additionally provides an electrode notching method for a secondary battery. The method according to the present invention comprises: a notching step of shearing an electrode, which is continuously supplied, into a predetermined electrode pattern; a drying step of irradiating infrared rays onto a surface of the notched electrode to dry the electrode; and a collecting step of collecting the dried electrode, wherein, in the drying step, the electrode is dried while passing through a drying space into which the infrared rays are irradiated, the infrared rays are reflected by a reflection plate, so that the infrared rays are concentrated onto the surface of the electrode, and the drying space has a portion formed in a horizontal direction parallel to the ground and a portion formed in a vertical direction perpendicular to the ground.

A transfer roller may be disposed between the portion formed in the horizontal direction and the portion formed in the vertical direction in the drying space, and a transfer direction of the electrode may be changed through the transfer roller.

The electrode notching apparatus for the secondary battery according to the present invention comprises the notching unit, the drying unit, and the collecting unit. The drying unit may be configured so that the notched electrode is continuously dried to quickly dry the moisture remaining on the electrode, thereby reducing the entire process time and improving the productivity. That is, the productivity may be improved when compared to the conventional process in which the notched electrode manually moves and is stored so as to be dried in the unit of the certain quantity.

The drying unit according to the present invention comprises a plurality of heating lamps. Thus, the heating lamps may dry the surface of the electrode by irradiating the infrared rays, and thus, the drying rate may be excellent, the surface of the electrode may be dried more uniformly than the conventional hot air drying, and the drying time may be reduced. Particularly, the heating lamps of the present invention may irradiate the infrared rays having the wavelength, in which the absorption rate of the infrared rays into the active material is higher than that of the infrared rays into the collector (that is to say, infrared rays having a specific wavelength, which are reflected by the collector that is the metal material and are absorbed into the active material, are irradiated), to generate the heat in only the active material of the electrode. That is, the drying may be performed in the manner, in which the molecular motion is activated in only the active material, to prevent the collector from being thermally deformed, and also, the temperature rise inside the drying chamber may be suppressed to improve the durability of the peripheral devices.

Also, since the lamp part is manufactured by mounting the heating lamps on the housing with the reflection plate mounted, the infrared rays of the heating lamps may be concentrated into one point without scattering the infrared rays, and if necessary (the case in which the heating lamps have different breakage lifetimes or product lifetimes, or the case in which the heating lamps having a higher output are required), the heating lamps may be easily replaced. Furthermore, each of the heating lamps may have the rod shape, and thus, the number of heating lamps to be mounted may be reduced when compared to the number of lamps, each of which has a bulb shape, and the wider area may be dried.

In addition, according to the present invention, the drying space in which the electrode is dried has the horizontal section formed in the horizontal direction and the vertical section formed in the vertical direction in the drying unit, and the transfer roller for switching the direction of the electrode may be disposed at the point, at which the horizontal section and the vertical section are switched, to increase in length of the drying space within the heating body, thereby improving the drying performance.

The present invention relates to an electrode notching apparatus and method for a secondary battery and may have an effect in which a process time is reduced, and drying is performed through infrared radiation instead of hot air to improve drying efficiency and reduce a defect occurrence rate.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings.

According Embodiment <NUM> of the present invention, an electrode notching apparatus for a secondary battery, which comprises a notching unit <NUM>, a drying unit <NUM>, and a collecting unit <NUM>, is provided.

Referring to <FIG>, the notching unit <NUM> provided in th notching apparatus is configured to shear an electrode, in which a coating portion coated with an electrode active material on a surface of a collector provided as metal foil and a non-coating portion that is distinguished from the coating portion and is not coated with the electrode active material are formed at a certain interval, to form a tab. That is, according to the present invention, the electrode is provided to the notching unit <NUM> in a state in which the electrode active material is continuously applied to one surface or both surfaces of the collector that has a constant width and is continuously provided and then is continuously discharged after being notched.

The notching unit <NUM> according to the present invention is configured so that the electrode <NUM> wound in a roll shape is transferred through a plurality of rollers. A processing device is disposed on the transfer path so that the processing device continuously shears the electrode into a predetermined pattern. A vision device and a sensor for monitoring whether the shearing is normally performed may be additionally disposed in the notching unit <NUM>.

The electrode <NUM> processed in and discharged from the notching unit <NUM> is transferred to the drying unit <NUM>. The electrode <NUM> continuously passes through the drying unit <NUM> so as to be dried. That is, the drying unit <NUM> is disposed between the notching unit <NUM> and the collecting unit <NUM> so that the electrode <NUM> is dried while continuously moving.

As illustrated in <FIG>, the drying unit comprises a heating body <NUM> having an inlet through which the electrode <NUM> is introduced and an outlet through the electrode <NUM> is discharged and provided with a drying space <NUM> (see <FIG>) that is a passage, through which the electrode <NUM> passes, therein and lamp parts <NUM> mounted on the heating body <NUM> to irradiate infrared rays onto a surface of the electrode <NUM> while the electrode <NUM> moves through the drying space <NUM>. Moisture contained in the surface of the electrode <NUM> is dried by the infrared rays irradiated from the lamp parts <NUM>, and the electrode <NUM> discharged from the drying unit <NUM> is wound and collected by the collecting unit <NUM>.

As illustrated in <FIG> and <FIG>, an auxiliary frame <NUM> having a vertical surface of which both side surfaces are vertically erected and a horizontal top surface is built in the heating body <NUM>. Also, the lamp parts <NUM> are mounted on the vertical surface and the horizontal surface of the auxiliary frame <NUM>, and the lamp parts <NUM> are respectively installed on a wall surface within the heating body <NUM>, which face the lamps mounted on the auxiliary frame <NUM>.

Thus, the lamp parts <NUM> are continuously disposed so that the lamp parts <NUM> mounted on the auxiliary frame <NUM> and the lamp parts <NUM> installed on the wall surface within the heating body <NUM> are paired with each other. Also, the drying space <NUM> serving as the drying space through which the electrode <NUM> passes is formed between the pair of lamps <NUM> facing each other. The drying space <NUM> has one side connected to the inlet <NUM> of the heating body <NUM> and the other side connected to the outlet <NUM> of the heating body <NUM>. Thus, the electrode <NUM> is introduced into the notching unit <NUM> to pass through the drying unit <NUM> and then is discharged to the collecting unit <NUM>.

The drying space <NUM> may be divided into a horizontal section <NUM> formed in a horizontal direction and a vertical section <NUM> formed in a vertical direction so that the path onto which the infrared rays are irradiated increases to improve a drying rate of the electrode. Also, a transfer roller for switching a direction is disposed at a point at which the electrode <NUM> is switched between the horizontal section <NUM> and the vertical section <NUM>.

Thus, as illustrated in the drawing, the vertical section <NUM> of the drying space <NUM> is formed at a position at which the electrode <NUM> passes through the vertical surface of the auxiliary frame <NUM>, and the vertical section <NUM> is formed at a position at which the electrode <NUM> passes through the horizontal surface of the auxiliary frame <NUM>. For reference, although two vertical sections <NUM> are connected to one horizontal section <NUM> in the drawing, the horizontal section <NUM> and the vertical sections <NUM> may be disposed in various shapes according to sizes and an arranged structure of the lamp parts <NUM>.

As illustrated in the cross-sectional view of <FIG> and the perspective view of <FIG>, the lamp part <NUM> according to the present invention has a structure in which a heating lamp <NUM> and a reflection plate <NUM> are mounted on a housing <NUM>.

The housing <NUM> has a structure of which one side is opened so that light of the heating lamp <NUM> is irradiated toward the electrode <NUM>, and an opposite side is mounted on one of the horizontal surface and the vertical surface of the auxiliary frame <NUM> and the inner wall surface of the heating body <NUM>. Cables for supplying power to the heating lamp <NUM> may be additionally installed in the housing <NUM>, and safety devices for preventing overheating may be selectively installed in the housing <NUM>.

The heating lamp <NUM> mounted in the housing <NUM> is a lamp for irradiating infrared rays according to the applying of power. Although the heating lamp <NUM> has a straight shape (e.g., a circular rod shape having a predetermined diameter such as a rod-type fluorescent light) and is mounted in parallel to a longitudinal direction of the housing <NUM> in an embodiment of the present invention, the heating lamp <NUM> having a bulb shape may be mounted according to a process design. The infrared rays irradiated from the heating lamp <NUM> according to the present invention are infrared rays having a wavelength within a specific range (more specifically, in a range of <NUM> to <NUM>). Thus, moisture remaining on the surface of the electrode <NUM> absorbs the infrared rays irradiated from the heating lamp <NUM>, and the absorbed infrared rays stimulate electrons of the moisture to evaporate the moisture from a liquid state into a gas state. That is, the heating lamps according to the present invention irradiate infrared rays having a wavelength in a specific range in which the infrared rays are reflected more smoothly than absorption in the collector and smoothly absorbed into the active material to generate heat in only the active material of the electrode. That is, the drying may be performed in a manner, in which a molecular motion is activated in only the active material, to prevent the collector from being thermally deformed, and also, a temperature rise inside the drying chamber may be suppressed to improve durability of the peripheral devices. Here, an optimal wavelength range required for the drying may vary depending materials, surface gloss, and the like of the collector and the active material. However, when the optimal wavelength range may be determined through repeated experiments during the drying process. However, when the wavelength of the infrared rays is <NUM> or more, an absorption rate may be reduced to deteriorate drying efficiency. When the wavelength of the infrared rays is <NUM> or less, a reflectance of the collector may be reduced, and thus, the collector may also be heated. Thus, in this embodiment, it is preferable that the infrared rays have the wavelength within a range of <NUM> to <NUM>.

Furthermore, the reflection plate <NUM> which reflects the infrared rays irradiated from the heating lamp <NUM> toward the opened side of the housing <NUM> is mounted at an opposite side of the opened side with respect to the point at which the heating lamp <NUM> is installed in the housing <NUM>. The reflection plate <NUM> is made of a material having a high infrared reflectance and formed in a concave shape having a predetermined curvature so that the infrared rays are concentrated onto the surface of the electrode in consideration of reflection characteristics.

Since the heating lamp <NUM> having the straight shape (the rod shape) is used, and the infrared rays are concentrated by the reflection plate <NUM>, the lamp part <NUM> according to the present invention may more quickly heat the surface of the electrode when compared to the structure in which the heating lamp having the bulb shape is used.

<FIG> is a comparison graph illustrating a variation in temperature according to a heating time when the heating lamp having the bulb shape is used and when the heating lamp having the rod shape (a straight shape) is used. Here, a horizontal axis represents a moving speed (a heating time), and a vertical axis represents a surface temperature (°C) of the electrode. <FIG> is a comparison graph illustrating moisture (ppm) per unit area of a surface of a dried electrode when the heating lamp having the bulb shape is used and when the heating lamp having the rod shape (the straight shape) is used. As illustrated in <FIG>, since the infrared rays are concentrated onto the surface of the electrode <NUM> without being scattered, the heating lamp <NUM> according to the present invention may more quickly heat the surface of the electrode. That is, it is confirmed that the heating lamp <NUM> having the rod shape according to the present invention has heating efficiency that is improved by about two times compared to the heating lamp having the bulb shape. Also, as illustrated in <FIG>, even when the electrodes having different specifications are dried, the heating lamp <NUM> according to the present invention may provide a drying rate that is similar to that (similar to a final moisture content) when using the heating lamp having the bulb shape. That is, since the heating lamp <NUM> having the straight shape more quickly heats the electrode than the heating lamp having the bulb shape, a transfer speed of the electrode <NUM> may further increase to improve the drying rate while achieving the same level of drying performance.

For reference, although the heating body <NUM> illustrated in the drawing has a rectangular box shape, the heating body <NUM> may have a dome shape according to design requirements, and also, a transparent window may be attached to the heating body <NUM> so that a worker visually confirms the processes from the outside. Furthermore, an openable door or cover may be installed to facilitate replacement, equipment inspection, repair, and the like of the lamp parts <NUM>.

An interval between the lamp parts <NUM> and an arranged structure of the lamp parts <NUM> may be tuned according to moisture absorption of the electrode <NUM>, and the heating lamps <NUM> may be replaced with the heating lamps <NUM> that irradiate the optimum infrared rays according to the necessity of the process. For example, the interval between the lamp parts <NUM> may be regularly formed or irregularly formed so that a specific section is more concentratedly dried.

Although the heating lamps <NUM> are mounted one by one to the housings <NUM> in the drawing, two or more heating lamps <NUM> may be mounted if necessary. In this case, the reflection plate <NUM> may also be changed in shape. The housing <NUM> may be permanently coupled through welding or the like but may be detachably mounted through bolt coupling or an exclusive bracket (not shown). Here, the exclusive bracket may be able of slide the housing in up/down and left/right directions as well as adjust an angle thereof (within an allowed range), and it may be acceptable to mount several kinds of conventional housings <NUM> having different sizes and shapes.

Furthermore, an exhaust device <NUM> for discharging the moisture evaporated in the heating body <NUM> to the outside is mounted in the heating body <NUM>. The exhaust device <NUM> may comprise a device that absorbs the gaseous moisture evaporated in the heating body <NUM>, and an air conditioner (not shown) for properly maintaining a temperature and humidity within the heating body <NUM> may be used together. The air conditioner may discharge heat to the outside when the temperature within the heating body <NUM> abnormally increases to prevent electric device comprising the lamp part <NUM> from being damaged. Here, the air conditioner may be configured to be interlocked with a cooling device that may be mounted together with the individual lamp parts <NUM>.

Also, although the transfer direction is switched by the transfer rollers when the electrode <NUM> passes through the vertical section <NUM> and the horizontal section <NUM> in the drawing, an alternative device providing the same function may be used in place of the transfer rollers, and the transfer rollers may be connected to additional rotating devices to maintain proper tension and speed while the electrode <NUM> passes.

The electrode <NUM> passing through the above-described drying unit <NUM> is wound in the collecting unit <NUM>. As illustrated in <FIG>, the collecting unit <NUM> further comprises a collecting roller <NUM> winding the electrode <NUM> so as to be wound therearound and a plurality of small rollers that determine a winding position of the electrode <NUM> before winding the electrode <NUM> around the collecting roller <NUM> to maintain proper tension.

Hereinafter, a notching method using the electrode notching apparatus for the secondary battery according to Embodiment <NUM> of the present invention will be described according to Embodiment <NUM>.

As illustrated in <FIG>, an electrode notching method for a secondary battery according to an embodiment of the present invention comprises: a notching step (S10) of shearing an electrode <NUM> into a predetermined electrode pattern through a notching unit <NUM>; a drying step (S20) of directly heating a surface of the electrode <NUM> processed in the notching step by using the drying unit <NUM> to dry moisture remaining on the electrode <NUM>; and a collecting step (S30) of collecting the electrode <NUM> dried in the drying step into the collecting unit <NUM>.

In the notching step (S10), when an non-processed electrode <NUM> wound in a roll shape is supplied through a plurality of rollers, a processing device shears the electrode into a predetermined electrode pattern, and whether the shearing is faulty is detected through a vision device and a sensor.

In the drying step (S20), while the electrode <NUM> on which the notching step (S10) is performed passes through a heating body <NUM> of the drying unit <NUM>, infrared rays are irradiated onto the electrode <NUM> by a lamp part <NUM>, and the absorbed infrared rays stimulate molecules of the moisture to evaporate the moisture, thereby drying the electrode <NUM>. Here, the electrode <NUM> passes through a vertical section formed in a vertical direction perpendicular to the ground and a horizontal section <NUM> formed in a horizontal direction parallel to the ground so that a path on which the infrared rays are irradiated is lengthened.

In the collecting step (S30), the electrode discharged through an outlet of the heating body is wound and collected into the collecting unit <NUM>.

In the electrode notching apparatus for the secondary battery according to the present invention, the drying unit may be configured so that the notched electrode <NUM> is continuously dried to quickly dry the moisture remaining on the electrode <NUM>, thereby reducing the entire process time and improving the productivity. That is, the productivity may be improved when compared to the conventional process in which the notched electrode <NUM> moves and is stored so as to be dried in the unit of the certain quantity.

The drying unit <NUM> may comprise the plurality of heating lamps <NUM>. Thus, the heating lamps <NUM> may dry the surface of the electrode <NUM> by irradiating the infrared rays, and thus, the drying rate may be excellent, the surface of the electrode may be dried more uniformly than the conventional hot air drying, and the drying time may be reduced.

In addition, since the lamp part <NUM> is manufactured in the manner in which the heating lamp <NUM> is mounted in the housing <NUM> with the reflection plate <NUM> mounted, the infrared rays may be concentrated into one point on the surface of the electrode <NUM> without being scattered, and the heating lamp <NUM> may be easily replaced when the lamp is damaged, or the lifetime of the lamp is over, or if the heating lamp having a higher output is required.

Also, according to the present invention, the drying space <NUM> in which the electrode <NUM> is dried has the horizontal section <NUM> formed in the horizontal direction and the vertical section <NUM> formed in the vertical direction perpendicular to the horizontal section <NUM> within the drying unit <NUM>, and the transfer roller for switching the transfer direction of the electrode <NUM> may be disposed at the point at which the horizontal section <NUM> and the vertical section <NUM> are switched. Thus, the drying space may increase in length within the heating body <NUM> to improve the drying performance.

Claim 1:
A notching apparatus for a secondary battery, the notching apparatus comprising:
a notching unit (<NUM>) shearing an electrode (<NUM>) that is continuously supplied;
a drying unit (<NUM>) drying the electrode while the electrode discharged from the notching unit passes therethrough; and
a collecting unit (<NUM>) of collecting the electrode discharged from the drying unit,
wherein the drying unit (<NUM>) comprises a heating body (<NUM>) provided with a drying space (<NUM>) that is a passage, through which the electrode passes, therein and lamp parts (<NUM>) mounted on the heating body to irradiate infrared rays onto a surface of the electrode while the electrode moves through the drying space,
wherein each of the lamp parts (<NUM>) comprises:
a housing (<NUM>) of which a side facing the electrode is opened and which is fixed and mounted on the drying unit;
a heating lamp (<NUM>) mounted on the housing to generate the infrared rays according to applying of power; and
a reflection plate (<NUM>) mounted on the housing to reflect the infrared ray irradiated from the heating lamp to the opened side of the housing,
wherein the lamp parts (<NUM>) facing each other are continuously disposed or disposed with an interval therebetween, and
spaces between the lamps facing each other are connected to each other to form the drying space, and
wherein the drying space has a horizontal section (<NUM>) formed in a horizontal direction and a vertical section (<NUM>) formed in a vertical direction within the drying unit.