hereinafter , the present invention will be described more fully with reference to the accompanying drawings , in which exemplary embodiments of the invention are shown . as those skilled in the art will realize , the described embodiments may be modified in various different ways , all without departing from the spirit or scope of the present invention . fig1 is a configuration diagram showing a laser cleaning device for an electrode tab of a battery according to an exemplary embodiment . referring to fig1 , a laser cleaning device 100 according to an exemplary embodiment includes a cleaning housing 10 , a laser generator 20 , a laser transmitter 30 , and a laser emitting unit 40 . the operations of each member included in the laser cleaning device 100 are controlled by an integrated controller 11 . the laser generator 20 generates laser beam ( lb ) for removing an electrolyte solution which is a liquid pollutant stuck to the electrode tab 12 . the laser generator 20 includes a laser source 21 which generates the laser beam lb and an output controller 22 which controls the output of the laser beam ( lb ). the output controller 22 is connected to the integrated controller 11 so as to output the laser beam ( lb ) according to a control signal of the integrated controller 11 . as the laser beam ( lb ), a nd : yag pulse laser having a pulse width of 1 , 064 nm may be used . the laser beam ( lb ) vaporizes the electrolyte solution stuck to the electrode tab 12 using thermal energy so as to clean the electrode tab 12 . the laser cleaning does not apply friction to the electrode tab 12 , thereby making it possible to effectively clean the electrode tab 12 having a small thickness . the energy per the pulse of the laser beam ( lb ) may be 14 j to 34 j . if energy per pulse of the laser beam ( lb ) is smaller than 14 j , it is impossible to perform the cleaning using the laser beam ( lb ), and if energy per pulse of the laser beam ( lb ) is larger than 34 j , the electrode tab 12 may be damaged during the cleaning process . the laser generator 20 is positioned outside the cleaning housing 10 , and the laser emitting unit 40 is positioned inside the cleaning housing 10 . the laser transmitter 30 is installed between the laser generator 20 and the laser emitting unit 40 so as to transmit the laser beam ( lb ) generated by the laser generator 20 to the laser emitting unit 40 . the laser transmitter 30 may be formed as an optical fiber cable . the optical fiber cable is configured as an optical fiber transmitting a laser beam and a coating material surrounding the optical fiber . the laser emitting unit 40 emits the laser beam ( lb ) received from the laser transmitter 30 to the electrode tab 12 . the laser emitting unit 40 includes an optical device therein , thereby making it possible to control the size of the laser beam ( lb ), energy density ( j / cm 2 ) per unit area , and the shape of the laser beam ( lb ), etc . fig2 is a configuration diagram showing a laser emitting unit in the laser cleaning device shown in fig1 . referring to fig2 , a magnifying optical unit 42 , a modifying optical unit 43 , and a focusing optical unit 44 are included in the case 41 of the laser emitting unit 40 . the laser emitting unit 40 may use all three optical units or some of three optical units according to the purpose . the magnifying optical unit 42 includes a concave lens 421 and a convex lens 422 , and magnifies the laser beam ( lb ) to a desired magnification by the optical action of the concave lens 421 and the convex lens 422 . the magnifying optical unit 43 includes a laser absorption mask 432 having a center which is formed with an opening 431 . the laser beam ( lb ) provided at the laser absorption mask 432 is outputted in the same shape as the opening 431 while the edge is absorbed in the laser absorption mask 432 . the laser beam ( lb ) may be modified in an advantageous shape for cleaning , such as the shape of a circle , an oval , etc . the focusing optical unit 44 includes a convex lens 441 and focuses the laser beam ( lb ) passing through the modifying optical unit 43 so as to implement an energy density having sufficient intensity to perform the cleaning . the focusing optical unit 44 may include a lens moving unit 442 which changes the position of the convex lens 441 . the size of the laser beam ( lb ) and the energy density of the laser beam ( lb ) reaching the electrode tab 12 can be easily controlled by changing the position of the convex lens 441 using the lens moving unit 442 . referring back to fig1 , the laser cleaning device 100 may include a positional controller 46 which moves the laser emitting unit 40 in a horizontal direction and a vertical direction so as to control the light emitting position of the laser beam ( lb ). the positional controller 46 is installed in an inner wall of the cleaning housing 10 , and moves the laser emitting unit 40 in a direction parallel to the inner wall of the cleaning housing 10 , thereby making it possible to freely control the position of the laser beam ( lb ). the support 14 which supports the battery case 13 is positioned inside the cleaning housing 10 . the battery case 13 includes the electrode group and the electrolyte solution therein . the electrode group includes a positive electrode , a negative electrode , and a separator , wherein a portion of the electrode tab 12 is exposed to the outside of the battery case 13 . the electrode tab 12 may be a positive tab connected to a positive electrode and a negative tab connected to a negative electrode . on the other hand , two electrode tabs ( positive tab and negative tab ) may be exposed to the outside of the battery case 13 . fig1 shows , by way of example , the case where one electrode tab 12 is exposed to the outside of the battery case 13 . after the injection of the electrolyte solution is completed , the electrode tab 12 is in a state wherein it has fallen or is inclined in any one direction . in this state , since the laser beam ( lb ) cannot be irradiated onto the electrode tab 12 , the electrolyte solution stuck to the electrode tab 12 cannot be removed . therefore , the laser cleaning device 100 includes an erect device 50 which erects and spreads the electrode tab 12 and facilitates the laser cleaning device . fig3 is a schematic diagram showing an erect device in the laser cleaning device shown in fig1 . referring to fig3 , the erect device 50 includes a holder unit 51 which fixes the electrode tab 12 by pressing the electrode tab 12 and a holder unit 51 , and a vertical moving unit 52 which moves the holder unit 51 in a vertical direction . the holder unit 51 may be configured of tongs . the vertical moving unit 52 may include a linear motion device connected to the holder unit 51 , and a cam 54 which drives the linear motion device 53 . the vertical moving unit 52 may be formed of a combination of other mechanical devices other than the exemplary embodiment shown in fig3 . when the holder unit 51 fits in the electrode tab 12 and the cam 54 is then driven , the electrode tab 12 fixed to the holder unit 51 is flatly spread while being erected by a backward action . therefore , the surface area of the electrode tab 12 onto which the laser beam ( lb ) is irradiated is expanded , thereby making it possible to improve the cleaning efficiency by the laser beam ( lb ). the electrode tab 12 may maintain an angle of 80 ° to 100 ° with respect to the irradiation direction of the laser beam ( lb ). referring back to fig1 , a plurality of battery cases 13 are included in the cleaning housing 10 , and the plurality of battery cases 13 may move along the defined orbit and reach the cleaning position one by one . the cleaning position is defined as a position which receives the laser beam ( lb ), facing the laser emitting unit 40 . fig4 is a schematic diagram showing a battery case and a support in the laser cleaning device shown in fig1 . referring to fig4 , the support 14 includes a plurality of supporting holders 141 to support the plurality of battery cases 13 at a predetermined distance . the lower portion of the support 14 is provided with the first transferring unit 15 to move the support 14 and the battery case 13 along the defined orbit . the first transferring unit 15 may move the support 14 in a straight direction or it may move the support 14 along an orbit in the shape of a closed curved line , such as a circle , an oval , etc . in this case , the plurality of erect devices 50 are provided in correspondence to the number of battery cases 13 , and the second transferring unit 16 is provided on the upper portions of the erect devices 50 so as to move the plurality of erect devices 50 along the same orbit as the first transferring unit 15 . the first transferring unit 15 and the second transferring unit 16 are configured as a combination of a rack gear , a pinion gear and a motor , or may be configured as a combination of other mechanical devices . the electrode tab 12 of the battery case 13 which is disposed at the cleaning position receives the laser beam ( lb ) so as to perform the cleaning operation . then , the first transferring unit 15 and the second transferring unit 16 are operated , and they dispose and stop the electrode tab 12 of the battery case 13 . then , the electrode tab 12 of the battery case 13 disposed at the cleaning position receives the laser beam ( lb ), thereby performing the cleaning operation . in this case , while the first transferring unit 15 and the second transferring unit 16 are operated , the laser source 21 is turned off so that the laser beam ( lb ) is not emitted . by a repeated process , the plurality of electrode tabs 12 can be continuously cleaned . referring back to fig1 , the laser cleaning device 100 includes a laser absorber 17 which is disposed at the rear of the electrode tab 12 in the cleaning housing 10 . the laser absorber 17 is disposed so as to face the laser emitting unit 40 , putting the electrode tab 12 therebetween , and is formed so as to have a larger area than the electrode tab 12 . a diameter of the laser beam ( lb ) reaching the electrode tab 12 is set to be larger than a width of the electrode tab 12 in order to smoothly clean the electrode tab 12 . thereby , a portion of the laser beam ( lb ) reaches the electrode tab 12 so as to vaporize the electrode solution stuck to the electrode tab 12 , but the remaining portion is diffused to the inside of the cleaning housing 10 . in this case , the laser absorber 17 receives the laser beam ( lb ) which does not reach the electrode tab 12 , thereby absorbing the remaining energy of the laser beam ( lb ). if it is assumed that there is no laser absorber 17 , the laser beam which does not reach the electrode tab 12 , among the laser beam ( lb ) emitted from the laser emitting unit 40 , reaches other members in the cleaning housing 10 , and damages them or diffuses in several directions in the cleaning housing 10 so as to cause the fault of other members . however , the laser cleaning device 100 according to the present exemplary embodiment includes the laser absorber 17 so as to solve the above - mentioned problem . the laser cleaning device 100 include an exhaust unit 60 that safely removes the pollutants generated during the cleaning process . the exhaust unit 60 includes a blower 61 which sucks air including pollutants , a dust collecting device 62 which collects and removes the pollutants , and an exhaust duct 63 which discharges air from which pollutants are removed to the outside of the cleaning housing 10 . the exhaust unit 60 may be disposed just on the battery case 13 and the erect device 50 in order to rapidly remove the pollutants . the pollutants can be safely removed by using the above - mentioned exhaust unit 60 . furthermore , the laser cleaning device 100 includes a monitoring system which monitors and records the cleaning process of the electrode tab 12 . the monitoring system includes a photographing unit 71 which photographs the cleaning process of the electrode tab 12 and a display unit 72 which displays the image information obtained by the photographing unit 71 . the photographing unit 71 may be fixed to the inside of the cleaning housing 10 ( for example , the casing 41 of the laser emitting unit 40 ), and the display unit 72 is disposed outside the cleaning housing 10 . fig5 is a schematic diagram showing an electrode tab and a laser absorber in the laser cleaning device shown in fig1 . an erecting device is omitted for convenience in fig5 . referring to fig5 , the electrode tab 12 has predetermined width w and length l , and is formed so as to have a thickness of approximately 1 mm . for example , the width w of the electrode tab 12 may be approximately 3 mm and the length l of the electrode tab 12 exposed to the outside of the battery case 13 may be approximately 6 mm . the laser beam ( lb ) may be a circle , and the diameter d of the laser beam ( lb ) reaching the electrode tab 12 may be two to three times as large as the width w of the electrode tab 12 . the laser beam ( lb ) is irradiated onto one surface of the electrode tab 12 facing the laser emitting unit 40 , but the electrolyte solution stuck to an opposite surface of the electrode tab 12 is vaporized and removed together by the thermal transfer of the electrode tab 12 . if it is determined that the diameter of the laser beam ( lb ) is two times smaller than the width w of the electrode tab 12 , at least one of the position of the laser beam ( lb ) and the position of the electrode tab 12 should be very precisely controlled , such that additional processes are required . meanwhile , if it is determined that the diameter of the laser beam ( lb ) exceeds three times the width w of the electrode tab 12 , the energy density per unit area of the laser beam ( lb ) is low , such that the cleaning effect is deteriorated . fig6 is a flowchart showing a laser cleaning method for an electrode tab of a battery according to an exemplary embodiment . referring to fig6 , a laser cleaning method for an electrode tab of a battery according to the exemplary embodiment includes : a first step ( s 10 ) of mounting the battery case , from which the electrode tab is exposed , in the cleaning housing ; a second step ( s 20 ) of generating the laser beam for controlling the output by using the generator ; a third step ( s 30 ) of transmitting the laser beam to the laser emitting unit in the cleaning housing by the laser transmitter ; and a fourth step ( s 40 ) of controlling the optical magnification of the laser emitting unit so as to emit the optimized laser beam to the electrode tab . in the first step s 10 , the electrode tab 12 may be straightly erected and spread by using the erect device 50 installed in the cleaning housing 10 . fig7 is a diagram schematically showing the electrode tab at the first step shown in fig6 , wherein the electrode tab 12 may be maintained at an angle θ of 80 ° to 100 ° with respect to the irradiation direction of the laser beam ( lb ). if it is determined that the angle θ of the electrode tab 12 is smaller than 80 ° or exceeds 100 °, the energy density per the unit area of the laser beam ( lb ) is low , such that the cleaning efficiency is deteriorated . in addition , the plurality of battery cases 13 are installed in the cleaning housing 10 and the plurality of battery cases may be sequentially positioned one by one by using the first transferring unit 15 and the second transferring unit 16 . in the second step s 20 , the laser beam may be the nd : yag pulse laser and the energy per pulse of the laser beam ( lb ) may be 14 j to 34 j . in the fourth step , the laser emitting unit 40 uses at least one of the above - mentioned magnifying optical unit 42 , the modifying optical unit 43 , and the focusing optical unit 44 to control the shape and size of the laser beam ( lb ) and the energy density per unit area , and emit the controlled laser beam ( lb ) to the electrode tab 12 . in this case , the size of the laser beam ( lb ) is larger than the area of the electrode tab 12 exposed to the outside of the battery case 13 , and the diameter of the laser beam ( lb ) is set so as to be two to three times larger than the width of the electrode tab 12 . the electrode tab 12 receiving the laser beam ( lb ) is cleaned , while the electrolyte solution stuck to the surface is vaporized by the thermal energy of the laser beam ( lb ). in addition , the laser absorber 17 is positioned at the rear of the electrode tab 12 , thereby absorbing the remaining energy of the laser beam ( lb ). the pollutants , such as fume , generated during the laser cleaning process are collected in the dust collecting device 62 installed in the cleaning housing 10 , and are safely removed . the above - mentioned laser cleaning technology does not apply the friction to the electrode tab 12 , such that it is efficient in cleaning the electrode tab 12 having a small thickness , and the damage or secondary pollution of the electrode tab 12 does not occur . while this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments , it is to be understood that the invention is not limited to the disclosed embodiments , but , on the contrary , is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims .