Patent Description:
The present invention relates to an electrode running roller and a notching device comprising the same.

With increasing technological development and demand for mobile devices, a rechargeable secondary battery is widely used as energy sources for various mobile devices. In addition, the secondary battery is attracting attention as an energy source for an electric vehicle, a hybrid vehicle and the like, which are proposed as a solution to air pollution caused by existing a gasoline vehicle and a diesel vehicle.

The secondary battery is classified into a coin-shaped battery, a cylindrical battery, a prismatic battery, and a pouch-shaped battery according to the shape of the battery case in which the electrode assembly is incorporated. In general, the electrode assembly incorporated in the battery case is classified into a jelly-roll type in which a separation membrane is interposed and wound up between an anode and a cathode, a stack type in which a plurality of unit cells with the separation membrane interposed between the anode and the cathode are stacked, and a stack/folding type in which the unit cells are wound with a separation film.

Such a secondary battery can be manufactured by coating an electrode mixture, which is a mixture of an electrode active material, a conductive material, a binder, etc., on an electrode current collector and then drying it to manufacture an electrode, laminating the manufactured electrode together with the separation membrane to form an electrode assembly, and then embedding and sealing in a battery case together with an electrolyte. The electrode assembly is classified into a stack type, a folding type, a stack-folding type, etc. depending on the manufacturing methods. In the case of a stack type or stack-folding type electrode assembly, the unit assemblies have a structure in which an anode and a cathode are sequentially laminated with a separation film interposed therebetween. In order to manufacture such an electrode assembly, it is first necessary to manufacture the anode and the cathode having electrode tabs formed thereon.

That is, in order to manufacture a unit electrode having electrode tabs, first, a notching process is required to form the electrode tabs on a continuous electrode sheet coated with an electrode active material on one or both sides thereof. The notching process generally consists of a process of placing an electrode sheet on a die and punching out a part of the electrode sheet using a press. Here, the electrode sheets are conveyed by running rollers that run in synchronism with the operation of the press, and are sequentially punched to form electrode tabs.

The surface of the electrode sheet is made up of a coating portion coated with an electrode active material, and a non-coating portion coated with no electrode active material, and the running roller is formed in a cylindrical shape. The electrode sheet moves in close contact with an outer peripheral surface of the running roller. When the electrode sheet runs on the electrode running roller, since the coating portion and the non-coating portion on the surface of the electrode sheet have different coefficients of friction, a difference occurs in a tension with the electrode running roller. Therefore, there are problems such as breakage of the non-coating portion and breakage at the boundary between the coating portion and the non-coating portion.

Therefore, there is a great need for a technology that can solve the above problems.

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

An object of the present invention is to provide an electrode running roller that can solve the problem of occurrence of breakage at the boundary between a coating portion and a non-coating portion of an electrode sheet, when the electrode sheet is conveyed by the electrode running roller.

Another object of the present invention is to provide a notching device comprising the electrode running roller.

In order to achieve the above object, the present invention provides an electrode running roller designed to cause an electrode sheet including a current collector which is coated with an electrode active material to run,.

In an embodiment of the invention, a ratio of the length of the cylindrical section to a length of the tapered section may be <NUM>:<NUM> to <NUM>:<NUM>.

In an embodiment of the invention, the tapered section may have a truncated conical form.

In an embodiment of the present invention, the electrode sheet may have a coating portion coated with an electrode active material, and a non-coating portion not coated with the electrode active material, and
the electrode running roller may be dimensioned such that the non-coating portion is positioned in the tapered section of the electrode running roller.

In an embodiment of the present invention, the electrode running roller may be dimensioned such that the coating portion of the electrode sheet extends up to a boundary between the cylindrical section and the tapered section of the electrode running roller.

In an embodiment of the present invention, the cylindrical section of the running roller may be dimensioned such that a portion of the electrode sheet, except the non-coating portion, may be in contact with the outer peripheral surface of the cylindrical section.

Also, the present invention provides a notching device for forming an electrode tab on a continuous electrode sheet in which an electrode active material is coated on one side or both sides of a current collector in a manufacturing process of a battery cell.

The electrode running roller of the present invention includes a tapered section extending from one side end of a cylindrical section, and by disposing the non-coating portion of the electrode sheet in the tapered section, it is possible to reduce breakages that occur at the boundary between the coating portion and the non-coating portion of the electrode sheet when the electrode is running.

Hereinafter, the present invention will be described in detail based on the accompanying drawings so that a person having ordinary knowledge in the technical field to which the present invention belongs can easily carry it out. This invention may, however, be embodied in many different forms and is not limited to the embodiments set forth herein.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

Furthermore, terms or words used in the specification and claims should not be construed as being limited to its customary or dictionary meaning, and should be interpreted by the inventors as a meaning and concept consistent with the technical idea of the present invention, based on the principle that the concepts of the terms can be properly defined to describe their invention in the best possible manner.

<FIG> is a perspective view showing an electrode running roller according to an embodiment of the present invention.

Referring to <FIG>, an electrode running roller <NUM> according to an embodiment of the present invention is an electrode running roller <NUM> which causes an electrode sheet <NUM> in which a current collector <NUM> is coated with an electrode active material to run, and the electrode running roller <NUM> includes a cylindrical section <NUM> and a tapered section <NUM> extending from one end portion of the cylindrical section <NUM>. The tapered section <NUM> is configured such that the outer diameter gradually decreases toward the distal end portion of the tapered section <NUM>.

Here, referring to <FIG>, the electrode sheet <NUM> includes a coating portion <NUM> coated with an electrode active material on one side or both sides of a current collector <NUM> and a non-coating portion <NUM> not coated with the electrode active material.

Specifically, the coating portion <NUM> of the electrode sheet <NUM> is continuously coated with the electrode active material along the running direction of the electrode running roller <NUM>. Further, the non-coating portion <NUM> may not be coated with the electrode active material on the side portion in the running direction of the electrode running roller <NUM>.

Further, in the electrode running roller <NUM>, the non-coating portion <NUM> of the electrode sheet <NUM> is disposed to be positioned in the tapered section <NUM> of the electrode running roller <NUM>.

<FIG> is a perspective view showing an electrode running roller according to a conventional embodiment.

Referring to <FIG>, the conventional electrode running roller <NUM> includes a cylindrical section <NUM> and a variable section <NUM> having a smaller diameter than the cylindrical section <NUM> so that a step S1 is formed on the outer peripheral surface of the cylindrical section.

At this time, the coating portion <NUM> of the electrode sheet <NUM> can be disposed at a position where it is in contact with the outer peripheral surface of the cylindrical section <NUM>, and the non-coating portion <NUM> can be disposed to be positioned in the variable section <NUM> of the electrode running roller <NUM>. In addition, the boundary between the coating portion <NUM> and the non-coating portion <NUM> can be in contact with the outer peripheral surface of the cylindrical section <NUM>. Therefore, when the electrode running roller <NUM> runs, because the cylindrical section <NUM> directly abuts on the boundary between the coating portion <NUM> and the non-coating portion <NUM> and acts as an external force, the effect of blocking and dispersing stress is minimal. Therefore, when the electrode sheet <NUM> is conveyed by the electrode running roller <NUM>, there is a problem that the electrode sheet <NUM> is broken.

Therefore, the present invention attempts to solve the above problem by providing the electrode running roller <NUM> comprising the tapered section <NUM> extending from one side end portion of the cylindrical section <NUM>.

Hereinafter, the electrode running roller <NUM>, which is an embodiment of the present invention, will be described in more detail with reference to <FIG>.

In an embodiment of the invention, the ratio of the length (C) of the cylindrical section and the length (L) of the tapered section may be between <NUM>:<NUM> and <NUM>:<NUM>, preferably between <NUM>:<NUM> and <NUM>:<NUM>. Since it is possible to reduce the stress generated at the boundary between the coating portion <NUM> and the non-coating portion <NUM> of the electrode sheet <NUM>. Within the above ratio range, occurrence of the breakage of the electrode sheet <NUM> can be prevented. Specifically, if the maximum effective stress generated at the boundary between the coating portion <NUM> and the non-coating portion <NUM> of the electrode sheet <NUM> is <NUM> MPa or more, the electrode sheet <NUM> may break. However, if the ratio of the length C of the cylindrical section to the length L of the tapered section is <NUM>:<NUM> to <NUM>:<NUM>, the maximum effective stress generated at the boundary between the coating portion <NUM> and the non-coating portion <NUM> of the electrode sheet <NUM> is less than <NUM> MPa, and it is possible to solve the problem of breakage of the electrode sheet <NUM> accordingly. If the ratio of the length C of the cylindrical section to the length L of the tapered section is out of the range of <NUM>:<NUM> to <NUM>:<NUM>, the stress is generated at <NUM> MPa or more, and the effect of improving the breakage problem generated in the electrode sheet <NUM> is low.

Also, in an embodiment of the present invention, the tapered section <NUM> has a truncated conical shape, and forms an outer peripheral surface that is inclined at an angle of <NUM> to <NUM> degrees, preferably, an angle of <NUM> to <NUM> degrees, toward the central axis P. In the above angle range, the contact between the non-coating portion <NUM> of the electrode sheet <NUM> and the tapered section <NUM> can be minimized, and the breakage of the electrode sheet <NUM> can be prevented.

<FIG> is a perspective view showing a state in which electrode running rollers according to an embodiment of the present invention are applied.

Referring to <FIG>, in the electrode running roller <NUM> according to an embodiment of the present invention, the non-coating portion <NUM> of the electrode sheet <NUM> is positioned in the tapered section <NUM>, and in the electrode running roller <NUM>, the coating portion <NUM> of the electrode sheet <NUM> can be disposed at the boundary between the cylindrical section <NUM> and the tapered section <NUM>. In addition, in the electrode sheet <NUM>, the portion except for the non-coating portion <NUM> can be in contact with the outer peripheral surface of the cylindrical section <NUM>.

Therefore, in the electrode running roller <NUM> according to the embodiment of the present invention configured as described above, by forming the tapered section <NUM> at one end portion of the cylindrical section <NUM> in which the electrode sheet <NUM> is in close contact with the outer peripheral surface when the electrode sheet <NUM> runs, since the portion of the electrode sheet <NUM> except for the non-coating portion <NUM> not coated with the electrode active material can be brought into close contact with the outer peripheral surface of the cylindrical section <NUM>, it is possible to prevent breakage that occurs in the boundary between the non-coating portion <NUM> and the coating portion <NUM>.

Hereinafter, a notching device according to an embodiment of the present invention will be described below.

<FIG> is a front view showing a notching device comprising the electrode running rollers according to an embodiment of the present invention.

Referring to <FIG>, a notching device <NUM> according to an embodiment of the present invention comprises electrode running rollers <NUM> which causes the electrode sheet <NUM> to run.

More specifically, the notching device <NUM> according to an embodiment of the present invention is made up of a press <NUM>, a die <NUM> and an electrode running roller <NUM>, and the continuous electrode sheet <NUM>, in which the electrode active material is applied to one or both sides of a current collector, runs on the electrode running roller <NUM> of the notching device <NUM>.

The press <NUM> punches the electrode sheet <NUM> at regular intervals so that electrode tabs are formed on the electrode sheet <NUM>, and the electrode running roller <NUM> functions to convey the electrode sheet <NUM> by the press <NUM> in synchronization with the operation of the press <NUM>.

Further, the die <NUM> is formed with an opening <NUM> having a shape corresponding to the press <NUM> so that scrap punched by the press <NUM> can be discharged.

The electrode running roller <NUM> is according to an embodiment of the present invention described above.

Claim 1:
An electrode running roller (<NUM>) designed to cause an electrode sheet (<NUM>) including a current collector (<NUM>) which is coated with an electrode active material to run,
wherein the running roller (<NUM>) comprises a cylindrical section (<NUM>), and a tapered section (<NUM>) extending from one end portion of the cylindrical section (<NUM>), and
the tapered section (<NUM>) has a shape in which an outer diameter gradually decreases toward a distal end portion of the tapered section (<NUM>),
characterized in that the tapered section (<NUM>) forms an outer peripheral surface inclined at an angle of <NUM> to <NUM> degrees toward a central axis (P) on the basis of an outer peripheral surface of the cylindrical section (<NUM>).