Patent Publication Number: US-2022214164-A1

Title: Alignment inspection apparatus for electrode assembly and alignment inspection method for electrode assembly using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. Ser. No. 16/636,244, filed Feb. 3, 2020, which is a national phase application of PCT/KR2019/003406, filed Mar. 22, 2019, and claims the priority of Korean Patent Application No. 10-2018-0036851, filed on Mar. 29, 2018, in the Korean Intellectual Property Office, the disclosure of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an alignment inspection apparatus for an electrode assembly and an alignment inspection method, and more particularly, to an alignment inspection apparatus for an electrode assembly, which inspects alignment quality of an internal electrode laminated in the form of a sandwich between separators in a mono cell, and an align inspection method for an electrode assembly using the same. 
     BACKGROUND ART 
     Batteries (cells) that generate electric energy through physical or chemical reaction to supply the generated electric energy to the outside are used when AC power to be supplied to the building is not obtained, or DC power is required according to the living environments surrounded by various electric and electronic devices. 
     Among such batteries, primary batteries and secondary batteries, which are chemical batteries using chemical reaction, are being generally used. The primary batteries are consumable batteries which are collectively referred to as dry batteries. Also, secondary batteries are rechargeable batteries that are manufactured by using a material in a redox process between current and a substance is repeatable several times. When the reduction reaction is performed on the material by the current, power is charged, and when the oxidation reaction is performed on the material, power is discharged. Such the charging-discharging is repeatedly performed to generate electricity. 
     A lithium ion battery of the secondary batteries is manufactured through the following processes. An active material is applied to each of a positive electrode conductive foil and a negative electrode conductive foil at a predetermined thickness, and a separator is disposed between the positive electrode conductive foil and the negative electrode conductive foil, and then, an electrode assembly, in which the positive electrode conductive foil, the separator, and the negative electrode conductive foil are wound several times in a jelly-roll or cylindrical shape, is accommodated into a cylindrical or prismatic can, a pouch, and the like to seal the resultant product, thereby manufacturing the lithium ion battery. 
     An electrode assembly according to the related art is disclosed in Korean Patent Publication No. 10-2017-0057778. 
     There is a method, in which mono cells are produced to be laminated so as to manufacture a finished cell, as one method for manufacturing an electrode assembly according to the related art. 
     In the mono cell, the two outermost electrodes have polarities different from each other. When the plurality of electrodes are laminated with a separator therebetween, there is a problem in that it is difficult to inspect alignment quality of the internal electrode disposed at an intermediate layer because the separator is laminated on each of top and bottom surfaces of the internal electrode. 
     DISCLOSURE OF THE INVENTION 
     Technical Problem 
     Therefore, the present invention has been made to solve the abovementioned problem, and an object of the prevent invention is to provide an alignment inspection apparatus for an electrode assembly, which inspects alignment quality of a mono cell, and an alignment inspection method for an electrode assembly using the same. 
     Technical Solution 
     An alignment inspection apparatus for an electrode assembly including a laminate, in which a separator, an internal electrode, a separator, and an upper electrode are sequentially laminated, according to an embodiment of the present invention includes a camera unit disposed above a central portion of the electrode assembly to photograph and inspect the electrode assembly and a side lighting unit obliquely irradiating light onto each of both ends of the upper electrode, which are symmetrical to each other with respect to the central portion of the electrode assembly. 
     The alignment inspection apparatus may further include a low lighting unit disposed below the electrode assembly to irradiate light onto a bottom surface of the electrode assembly. 
     The alignment inspection apparatus may further include a control unit measuring an aligned (alignment) state of the electrode assembly through photographed information of the electrode assembly observed through the camera unit. 
     The control unit may measure a distance between one end of an internal electrode tab and one end of the upper electrode of the electrode assembly. 
     An alignment inspection method for an electrode assembly through the alignment inspection apparatus of claim  1  according to an embodiment of the present invention includes an upper light irradiation step of obliquely irradiating light onto each of both ends of the electrode assembly, which are symmetrical to each other with respect to a central portion of the electrode assembly, by using a side lighting unit and a photographing step of photographing the electrode assembly through a camera unit disposed above the central portion of the electrode assembly. 
     The alignment inspection method may further include a measurement step of transmitting information observed through the camera unit to the control unit to allow the control unit to measure a distance between one end of an internal electrode tab and one end of an upper electrode. 
     An alignment inspection method for an electrode assembly through the alignment inspection apparatus of claim  1  according to another embodiment of the present invention includes an upper light irradiation step of obliquely irradiating light onto each of both ends of the electrode assembly, which are symmetrical to each other with respect to a central portion of the electrode assembly, by using a side lighting unit, a lower light irradiation step of irradiating light onto a bottom surface of the electrode assembly by using a lower lighting unit, and a photographing step of photographing the electrode assembly through a camera unit disposed above the central portion of the electrode assembly. 
     The alignment inspection method may further include a measurement step of transmitting information observed through the camera unit to the control unit to allow the control unit to measure a distance between one end of an internal electrode, which is projected to a separator by the lower lighting unit, and one end of upper electrode. 
     Advantageous Effects 
     According to the present invention, the alignment inspection of the internal electrode of the mono cell may be enabled by using the distance between the internal electrode tab and the upper electrode. 
     According to the present invention, the lighting is illuminated onto each of both ends and the bottom surface of the mono cell to measure the distance between the ends of the internal electrode and the upper electrode, thereby performing the alignment inspection of the internal electrode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view illustrating an inspection apparatus for an electrode assembly according to an embodiment of the present invention. 
         FIG. 2  is a plan view of only the electrode assembly of  FIG. 1 . 
         FIG. 3  is a side view of an inspection apparatus for an electrode assembly according to another embodiment of the present invention. 
         FIG. 4  is a plan view of only the electrode assembly of  FIG. 3 . 
         FIG. 5  is a flowchart sequentially illustrating an inspection method for an electrode assembly according to an embodiment of the prevent invention. 
         FIG. 6  is a flowchart sequentially illustrating an inspection method for an electrode assembly according to another embodiment of the prevent invention. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, an alignment inspection apparatus for an electrode assembly according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
     Terms or words used in the specification and claims should not be construed as limited to a lexical meaning, and should be understood as appropriate notions by the inventor based on that he/she is able to define terms to describe his/her invention in the best way to be seen by others. Therefore, embodiments and drawings described herein are simply exemplary and not exhaustive, and it will be understood that various equivalents may be made to take the place of the embodiments. 
     In the drawings, the dimension of each of components or a specific portion constituting the component is exaggerated, omitted, or schematically illustrated for convenience in description and clarity. Thus, the dimension of each element does not entirely reflect an actual size. Moreover, detailed descriptions related to well-known functions or configurations will be ruled out in order not to unnecessarily obscure subject matters of the present invention. 
       FIG. 1  is a side view illustrating an inspection apparatus for an electrode assembly according to an embodiment of the present invention, and  FIG. 2  is a plan view of only the electrode assembly of  FIG. 1 . 
     As illustrated in  FIGS. 1 to 2 , an inspection apparatus for an electrode assembly according to an embodiment of the present invention relates to an alignment inspection apparatus for an electrode assembly  10  including a laminate in which a separator  11 , an internal electrode  13 , a separator  11 , and an upper electrode  15  are sequentially laminated. The inspection apparatus for the electrode assembly according to an embodiment of the present invention includes a camera unit disposed above a central portion of the electrode assembly  10  to photograph and inspect the electrode assembly  10  and a side lighting unit  30  that obliquely irradiates light onto both ends of the upper electrode  15 , which are symmetrical to each other with respect to a central portion of the electrode assembly  10 . 
     The electrode assembly  10  may be a mono cell. The internal electrode  13  may be a positive electrode, and the upper electrode  15  may be a positive electrode having an opposite polarity to the internal electrode  13 . When the internal electrode  13  is the positive electrode, the upper electrode  15  may be the negative electrode having an opposite polarity to the internal electrode. 
     The internal electrode  13  may be disposed between the separators  11  in the form of a sandwich in which the separators are laminated on top and bottom surfaces of the internal electrode  13 . Also, since each of the separators  11  has a size greater than that of the internal electrode  13 , the internal electrode  13  may be completely covered by the separators disposed on the top and bottom surfaces of the internal electrode  13  when viewed in the plan view of  FIG. 2 . 
     The upper electrode  15  may have a size less than that of the internal electrode  13 . 
     An electrode tab extending from each of opposite ends of the internal electrode  13  and the upper electrode  15  may be formed on each of the ends. 
     The camera unit  20  may be installed above a central portion of the electrode assembly  10  so as to be spaced a predetermined distance from the electrode assembly  10  to photograph the electrode assembly  10  from an upper side of the central portion of the electrode assembly  10 . 
     The side lighting unit  30  is installed above each of both ends of the electrode assembly  10  so as to be spaced upward from th electrode assembly  10 . A spaced distance between the side lighting unit  30  and the electrode assembly  10  may be less than that between the camera unit  20  and the electrode assembly  10 . The reason in which the camera unit  20  is installed to have a longer distance from the electrode assembly  10  than the side lighting unit  30  may be for photographing the entire shape of the electrode assembly  10 . 
     The side lighting unit  30  may be provided in a pair on the ends of the electrode assembly, on which the electrode tab is not formed, of the ends of the electrode assembly  10  so that the pair of side lighting units  30  are symmetrical to each other with respect to the central portion of the electrode assembly  10 . Thus, the side lighting units  30  may obliquely irradiate light toward both the ends of the upper electrode  15  at a predetermined angle. 
     The side lighting units  30  may be spaced a predetermined distance from the electrode assembly  10  so as to be symmetrical to each other with respect to the central portion of the electrode assembly  10 , thereby obliquely irradiating light onto both the ends of the upper electrode  15 . Thus, the light may be irradiated onto an area A of the electrode assembly  10 , on which the light irradiated from the pair of side lighting unit  30  overlap each other. As a result, the shaded portion by the irradiation may be removed on the electrode assembly  10  photographed by the camera that disposed above the central portion to photograph the electrode assembly to maximize brightness of the lighting that irradiates the electrode assembly  10 . 
     The camera unit  20  may photograph the electrode assembly  10  to transmit photographed image information to a control unit  50 . 
     For example, the control unit  50  may be a central processing unit (CPU). The control unit  50  may measure a length d 1  between one end of an internal electrode tab  13   a  of the internal electrode  13  and one end of the upper electrode  15  of the electrode assembly  10  from the image information transmitted from the camera unit  20 . An alignment state between the upper electrode  15  and the internal electrode  13  may be inspected through the measured value. 
     Since the internal electrode tab  13   a  is a component that is attached to the internal electrode  13 , when the internal electrode moves, the internal electrode tab  13   a  may also move. Thus, a position of the internal electrode  13  may be grasped through a position of the internal electrode tab  13   a.    
       FIG. 3  is a side view illustrating an inspection apparatus for an electrode assembly according to another embodiment of the present invention, and  FIG. 4  is a plan view of only the electrode assembly of  FIG. 3 . 
     Referring to  FIGS. 3 and 4 , an inspection apparatus for an electrode assembly according to another embodiment of the present invention may include a low lighting unit  40  that is installed below the electrode assembly  10  to irradiate light to a bottom surface of the electrode assembly  10 . 
     The low lighting unit  40  may irradiate light to a separator  11  that forms the bottom surface of the electrode assembly  10  to project the internal electrode  13  laminated in the form of a sandwich between the two separators  11  to the separator  11 . A boundary line of the internal electrode, which is hidden by the separator, may be seen on an upper surface of the separator due to the lower lighting unit  40 . 
     Here, the camera unit  20  may photograph the electrode assembly  10  from an upper side of a central portion of the electrode assembly  10  to transmit photographed image information to the control unit  50 , and the control unit  50  may measure a distance d 2  between one end of the internal electrode  13  and one end of the upper electrode  15  on the basis of the transmitted image information. The distance d 2  may be a distance that is measured in a width direction. Also, a distance d 3  may be measured in a length direction. 
     An alignment state between the upper electrode  15  and the internal electrode  13  may be inspected through the measured value. When the distances are measured through the above-described manner, the distances may be more precisely measured when compared to the measurement through the internal electrode tab  13   a  according to an embodiment. 
     Hereinafter, an inspection method for an electrode assembly will be described in detail with reference to the accompanying drawings. 
       FIG. 5  is a flowchart sequentially illustrating an inspection method for an electrode assembly according to an embodiment of the prevent invention. 
     As illustrated in  FIG. 5 , an inspection method for an electrode assembly according to an embodiment of the present invention includes an upper light irradiation step (S 1 ) and a photographing step (S 2 ). 
     The upper light irradiation step (S 1 ) may be a step of irradiating light by using a side lighting unit  30  installed to be spaced upward from the electrode assembly  10 . Particularly, the upper light irradiation step (S 1 ) may be a step of installing the side lighting unit  30  on each of both ends, which are symmetrical to each other with respect to a central portion of the electrode assembly  10 , to obliquely irradiate light to both ends of the upper electrode  15 . 
     The photographing step (S 2 ) may be a step of photographing the electrode assembly  10  through a camera unit  20  disposed above the central portion of the electrode assembly  10  when light of the side lighting unit  30  is irradiated onto the electrode assembly  10  in the upper light irradiation step (S 1 ). 
     The inspection method may further include a measurement step of transmitting information of an image photographed by the camera unit  20  to a control unit  50  in the photographing step (S 2 ) to allow the control unit  50  to measure a distance d 1  between one end of an internal electrode tab  13   a  and one end of an upper electrode  15  from the image information transmitted from the camera unit  20 . 
       FIG. 6  is a flowchart sequentially illustrating an inspection method for an electrode assembly according to another embodiment of the prevent invention. 
     As illustrated in  FIG. 6 , an inspect method for an electrode assembly according to another embodiment of the present invention may include an upper light irradiation step (S 1 ), a lower light irradiation step (S 1 - 1 ), and a photographing step (S 2 ). 
     The upper light irradiation step (S 1 ) may be a step of irradiating light by using a side lighting unit  30  installed to be spaced upward from the electrode assembly  10 . Particularly, the upper light irradiation step (S 1 ) may be a step of installing the side lighting unit  30  on each of both ends, which are symmetrical to each other with respect to a central portion of the electrode assembly  10 , to obliquely irradiate light to both ends of the upper electrode  15 . 
     The lower light irradiation step (S 1 - 1 ) may be a step of irradiating light onto a bottom surface of the electrode assembly by using the lower lighting unit  40  installed below the central portion of the electrode assembly  10 . 
     The photographing step (S 2 ) may be a step of photographing the electrode assembly  10  by using a camera unit  20  disposed above the central portion of the electrode assembly  10  when light of the side lighting unit  30  is irradiated onto the electrode assembly  10  in the upper light irradiation step (S 1 ), and light of the lower lighting unit  40  is irradiated onto a bottom surface of the electrode assembly  10  in the lower light irradiation step (S 1 - 1 ) so that an internal electrode  13  is projected to a separator  11 . 
     The inspection method may further include a measurement step of transmitting information of an image photographed by the camera unit  20  to a control unit  50  in the photographing step (S 2 ) to allow the control unit  50  to measure a distance d 2  between one end of the internal electrode  13 , which is projected to the separator  11 , and one end of the upper electrode  15  from the image information transmitted from the camera unit  20 . 
     As described above, according to an embodiment of the present invention, the alignment inspection of the internal electrode of the mono cell may be enabled by using the distance between the internal electrode tab and the upper electrode. 
     Also, according to another embodiment of the present invention, the lighting is illuminated onto each of upper sides of both ends and the bottom surface of the mono cell to measure the distance between the ends of the internal electrode and the upper electrode, thereby performing the alignment inspection of the internal electrode. 
     Although the alignment inspection apparatus for the electrode assembly and the alignment inspection method for the electrode assembly using the same according to the present invention have been described above with reference to the exemplary drawings, various changes and modifications may be made thereto by one skilled in the art without departing from the scope and spirit of the invention as set forth in the appended claims.