Patent Publication Number: US-2023163342-A1

Title: Battery Cell Manufacturing Device and Battery Cell Manufacturing Method

Description:
CROSS CITATION WITH RELATED APPLICATION(S) 
     This application claims the benefit of Korean Patent Application No. 10-2021-0012232 filed on Jan. 28, 2021 and Korean Patent Application No. 10-2022-0012372 filed on Jan. 27, 2022 in the Korean Intellectual Property Office, the contents of which are incorporated herein by reference in their entirety. 
     The present disclosure relates to a battery cell manufacturing device and a battery cell manufacturing method, and more particularly, to a battery cell manufacturing device and a battery cell manufacturing method in which the amount of electrolyte loss is reduced and the quality is made uniform. 
     BACKGROUND 
     Along with the technology development and increased demand for mobile devices, demand for secondary batteries as energy sources has been increasing rapidly. Among these secondary batteries, a lithium secondary battery having high energy density and a high voltage, a long cycle lifespan, and a low self-discharge rate is commercially available and widely used. 
     A pouch for a secondary battery is mainly used as an exterior material for packaging such a secondary battery. The pouch is generally a pouch film having a structure of an outer layer, an adhesive layer, an aluminum layer, an adhesive layer, and an inner layer. However, the pouch-type secondary battery may be damaged in various processes. As an example, there is a problem that a part of the electrolyte in the pouch is pushed out to the outer peripheral surface in the process of sealing the outer peripheral surface of the pouch after the electrode assembly is incorporated into the pouch. 
       FIG.  1    is a flowchart showing a conventional battery cell manufacturing process.  FIG.  2    is a diagram showing a battery cell after the pre-sealing step of  FIG.  1   .  FIG.  3    is a diagram showing a battery cell after the sealing step of  FIG.  1   . 
     Referring to  FIG.  1   , the conventional battery cell manufacturing process includes a pre-sealing step (S 10 ) and a sealing step (S 20 ). Referring to  FIG.  2   , the pre-sealing step (S 10 ) is a step of forming a pre-sealing part  12  at the end part of an outer peripheral surface  11  of a battery cell  10 . Further, referring to  FIGS.  2  and  3   , the sealing step (S 20 ) is a step of forming the sealing part  15  on the outer peripheral surface  11  of the battery cell  10  by a first sealing tool  51  and a second sealing tool  55 . 
     Here, the pre-sealing part  12  prevents a part of the electrolyte in the pouch from leaking to the outside before the sealing step (S 20 ). However, by the pre-sealing step (S 10 ), a pocket part  11   p  may be formed between the pre-sealing part  12  and the central part of the battery cell  10  on the outer peripheral surface  11  of the battery cell  10 . In particular, a part of the electrolyte in the pouch may be contained in the pocket part  11   p . 
     However, referring to  FIG.  3   , in the conventional battery cell manufacturing process, the sealing step (S 20 ) is performed in a state in which the electrolyte in the pocket part  11   p  is not sufficiently removed, so that the electrolyte can remain in the pocket part  11   p  located between the pre-sealing part  12  and the sealing part  15 . That is, there is a problem that a part of the electrolyte to be contained in the battery cell  10  may be lost, and the quality of the battery cell  10  is not made uniform. Therefore, there is a need to develop a battery cell manufacturing device and a battery cell manufacturing method in which the amount of electrolyte loss is reduced and the quality is made uniform. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     It is an object of the present disclosure to provide a battery cell manufacturing device and a battery cell manufacturing method in which the amount of electrolyte loss is reduced and the quality is made uniform. 
     The objects of the present disclosure are not limited to the aforementioned objects, and other objects which are not described herein should be clearly understood by those skilled in the art from the following detailed description and the accompanying drawings. 
     Technical Solution 
     According to one aspect of the present disclosure, there is provided a battery cell manufacturing device comprising a battery case in which an electrode assembly and an electrolyte are incorporated, with a pocket part and a pre-sealing part being formed on the outer peripheral surface of the battery case, and the device including a jig for pressing the pocket part, wherein the jig includes a first jig located at the upper part and a second jig located at the lower part with respect to the pocket part, and wherein pressing and releasing of the first jig and the second jig to the pocket part are repeated at least once to press the pocket part. 
     The jig may be extended along the pocket part. 
     A width of the jig may be equal to or smaller than a length of the pocket part. 
     At least one of the first jig and the second jig may have a surface in contact with the pocket part that is covered with a soft member. 
     The soft member may be formed of a POM (polyoxymethylene) pad. 
     The soft member bottom part facing the pocket part may have a structure in which the thickness changes. 
     The soft member bottom part has a first end part and a second end part, and the thickness of the soft member may decrease as it goes from the first end part adjacent to the pre-sealing part toward the second end part farther from the pre-sealing part relative to the first end part. 
     The battery cell manufacturing device further includes a sealing tool including a first sealing tool located at an upper part and a second sealing tool located at a lower part, with respect to the pocket part, wherein the sealing tool may heat-seal at least a part of the pocket part pressed by the jig to form a sealing part on the outer peripheral surface of the battery case. 
     A width of the sealing tool may be equal to or smaller than a length of the jig. 
     According to another aspect of the present disclosure, there is provided a battery cell manufacturing method comprising a battery case in which an electrode assembly and an electrolyte are incorporated, the method comprising: a pre-sealing step of forming a pocket part and a pre-sealing part on the outer peripheral surface of the battery case; and a pressing step of pressing and bonding the pocket part with a jig, wherein the jig includes a first jig located at the upper part and a second jig located at the lower part, with respect to the pocket part, and wherein in the pressing step, pressing and releasing of the first jig and the second jig to the pocket part may be repeated at least once. 
     The pressing step may be repeated until the thickness of the pocket part is similar to the thickness of the end part of the outer peripheral surface of the battery case. 
     The battery cell manufacturing method further includes a sealing step that is performed after the pressing step, wherein in the sealing step, at least a part of the pocket part may be heat-sealed by a sealing tool to form a sealing part on the outer peripheral surface of the battery case. 
     Advantageous Effects 
     A battery cell manufacturing device and a battery cell manufacturing method according to an embodiment of the present disclosure presses the pocket part with a jig before sealing the pocket part formed on the outer peripheral surface of the battery case, thereby being able to reducing the amount of electrolyte loss and make the quality uniform. 
     The effects of the present disclosure are not limited to the effects mentioned above and additional other effects not described above will be clearly understood from the description of the appended claims by those skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a flowchart showing a conventional battery cell manufacturing process; 
         FIG.  2    is a diagram showing a battery cell after the pre-sealing step of  FIG.  1   ; 
         FIG.  3    is a diagram showing a battery cell after the sealing step of  FIG.  1   ; 
         FIG.  4    is a flowchart showing a battery cell manufacturing process according to an embodiment of the present disclosure; 
         FIG.  5    is a diagram showing a battery cell after the pre-sealing step of  FIG.  4   ; 
         FIGS.  6  to  8    are diagrams each showing a battery cell in a process in which the pressing step of  FIG.  4    is repeated; 
         FIG.  9    is a diagram showing a battery cell after the pressing step of  FIG.  4   ; 
         FIG.  10    is a diagram showing a battery cell after the sealing step of  FIG.  4   ; and 
         FIG.  11    is a diagram showing a modification of the battery cell manufacturing device shown in  FIG.  5   . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out them. The present disclosure may be modified in various different ways, and is not limited to the embodiments set forth herein. 
     A description of parts not related to the description will be omitted herein for clarity, and like reference numerals designate like elements throughout the description. 
     Further, throughout the description, when a portion is referred to as “including” a certain component, it means that the portion can further include other components, without excluding the other components, unless otherwise stated. 
       FIG.  4    is a flowchart showing a battery cell manufacturing process according to an embodiment of the present disclosure.  FIG.  5    is a diagram showing a battery cell after the pre-sealing step of  FIG.  4.0     
     Referring to  FIGS.  4  and  5   , a battery cell manufacturing device according to an embodiment of the present disclosure is a battery cell manufacturing device comprising a battery case  100  in which an electrode assembly and an electrolyte are incorporated, with a pocket part  110   p  and a pre-sealing part  120  being formed on the outer peripheral surface  110  of the battery case  100 , and the device including a jig  300  for pressing the pocket part  110   p . 
     Here, the jig  300  includes a first jig  310  located at the upper part and a second jig  350  located at the lower part, with respect to the pocket part  110   p . More specifically, the first jig  310  and the second jig  350  may be formed of the same material and shape. However, the present disclosure is not limited thereto, and can be appropriately deformed according to the shape of the battery case  100 . 
     Additionally, the first jig  310  and the second jig  350  can each perform upward and downward movements. As another example, one of the first jig  310  and the second jig  350  is fixed in a state in contact with the pocket part  110   p , and the remaining one can perform upward and downward movements. However, the present disclosure is not limited thereto, and can be appropriately deformed according to the shape of the battery case  100 . 
     Further, the jig  300  may be extended along the pocket part  110   p . In other words, the width of the jig  300  may be extended along the pocket part  110   p . As an example, the width of the jig  300  may be equal to or smaller than the length of the pocket part  110   p . 
     Thereby, in the battery cell manufacturing device according to an embodiment of the present disclosure, the jig  300  can relatively uniformly press the pocket part  110   p , and the quality of the battery cell can be further improved. 
     Further, in the jig  300  of the present embodiment, at least one of the first jig  310  and the second jig  350  may have a surface in contact with the pocket part  110   p  that is covered with a soft member  310 P. As an example, referring to  FIG.  5   , a surface of the first jig  310  in contact with the pocket part  110   p  may be covered with a soft member. 
     As an example, the soft member  310 P may be formed of a POM (polyoxymethylene) pad. However, the soft member  310 P is not limited thereto, and any material that can be sufficiently pressed without damaging the pocket part  110   p  can be applied. 
     Thereby, in the battery cell manufacturing device according to an embodiment of the present disclosure, a part of the jig  300  has a surface in contact with the pocket part  110   p  that is covered with a soft member  310 P, whereby the pocket part  110   p  can be uniformly pressed without overlapping each other, and can prevent sealing defects such as wrinkles during sealing from occurring on a part of the pocket part  110   p  that is subsequently pressed. 
       FIGS.  6  to  8    are diagrams each showing a battery cell in a process in which the pressing step of  FIG.  4    is repeated. 
     In the jig  300  of the present embodiment, the first jig  310  and the second jig  350  can repeatedly press and release the pocket part  110   p  at least once to press the pocket part  110   p . More specifically, referring to  FIG.  5   , the first jig  310  and the second jig  350  can each move toward the pocket part  110   p . Further, referring to  FIG.  6   , the first jig  310  and the second jig  350  may be in contact with the pocket part  110   p . Here, at least a part of the electrolyte contained in the pocket part  110   p  may move toward the inside of the battery case  100 . 
     Additionally, referring to  FIGS.  7  and  8   , the first jig  310  and the second jig  350  can move again to the pressed pocket part  110   p  and press the pocket part  110   p  again. Here, the remaining part of the electrolyte contained in the pocket part  110   p  may move toward the inside of the battery case  100 . If necessary, as shown in  FIGS.  7  and  8   , the pressing and releasing of the pocket part  110   p  can be repeated several times according to the movement of the first jig  310  and the second jig  350 . 
     Thereby, in the battery cell manufacturing device according to an embodiment of the present disclosure, the jig  300  can allow the electrolyte contained in the pocket part  110   p  to move toward the inside of the battery case  100  and thus, can reduce the amount of electrolyte loss in the battery case  100 . Further, the jig  300  may be repeatedly pressed and released on the pocket part  110   p , whereby the electrolyte remaining in the pocket part  110   p  can be minimized, and the quality of the battery cell can be further improved. 
       FIG.  9    is a diagram showing a battery cell after the pressing step of  FIG.  4   .  FIG.  10    is a diagram showing a battery cell after the sealing step of  FIG.  4   . 
     Referring to  FIGS.  9  and  10   , in the battery cell manufacturing device according to another embodiment of the present disclosure, the above-mentioned battery cell manufacturing device may further include a sealing tool  500  together with the jig  300 . 
     Here, the sealing tool  500  includes a first sealing tool  510  located at the upper part and a second sealing tool  550  located at the lower part, with respect to the pocket part  110   p . Here, the first sealing tool  510  and the second sealing tool  550  can heat-seal at least a part of the pocket part  110   p  pressed by the jig  300  to form a sealing part  150  on the outer peripheral surface  110  of the battery case  100 . 
     Thereby, in the battery cell manufacturing device according to an embodiment of the present disclosure, the sealing tool  500  can allow the battery case  100  to be sealed in a state in which the electrolyte contained in the pocket part  110   p  located between the pre-sealing part  130  and the sealing part  150  is minimized. That is, the battery case  100  can reduce the amount of electrolyte loss and improve the quality of the battery cell. 
     Further, the first sealing tool  510  and the second sealing tool  550  may be formed of the same material and shape. However, the present disclosure is not limited thereto, and can be appropriately deformed according to the shape of the battery case  100 . 
     Further, the first sealing tool  510  and the second sealing tool  550  may each perform upward and downward movements. As another example, one of the first sealing tool  510  and the second sealing tool  550  is fixed in contact with the pocket portion  110   p , and the remaining one can perform upward and downward movements. However, the present disclosure is not limited thereto, and can be appropriately deformed according to the shape of the battery case  100 . 
     Further, the width of the sealing tool  500  may be equal to or smaller than the width of the jig  300 . As an example, with respect to the pocket portion  110   p , the sealing tool  500  can be disposed adjacently at a position close to the inside of the battery case  100 . 
     Thereby, in the battery cell manufacturing device according to an embodiment of the present disclosure, the sealing tool  500  can allow the sealing part  150  to form at a position close to the inside of the battery case  100  in the pocket part  110   p , whereby a part of the electrolyte in the battery case  100  can be prevented from being leaked to the outer peripheral surface  110  of the battery case  100  in the subsequent charging/discharging process of the battery cell, and the quality of the battery cell can also be improved. 
     Referring to  FIG.  4   , a battery cell manufacturing method according to another embodiment of the present disclosure is a battery cell manufacturing method comprising a battery case  100  in which an electrode assembly and an electrolyte solution are incorporated, the method comprising: a pre-sealing step (S 100 ), a pressing step (S 200 ) and a sealing step (S 300 ). 
     Referring to  FIGS.  4  and  5   , the pre-sealing step (S 100 ) may be a step of forming the pre-sealing part  120  on the outer peripheral surface  110  of the battery case  100 . Here, the pre-sealing part  120  may be formed by heat-sealing the upper and lower parts of the outer peripheral surface  110  of the battery case  100  using a pre-sealing tool (not shown). 
     Thereby, in the battery cell manufacturing method according to an embodiment of the present disclosure, a part of the outer peripheral surface  110  of the battery case  100  is sealed by the pre-sealing step (S 100 ), so that the electrolyte in the battery case  100  cannot be leaked to the outside. 
     Additionally, the pre-sealing part  120  may be formed at a position spaced apart from the inside of the battery case  100  by a predetermined distance even on the outer peripheral surface  110  of the battery case  100 . Particularly, on the outer peripheral surface of the battery case  100 , a pocket part  110   p  may be formed between the inside of the battery case  100  and the pre-sealing part  120 . Here, the pocket part  110   p  may include at least a part of the electrolyte in the battery case  100 , as described above. 
     Referring to  FIGS.  4 , and  6  to  8   , the pressing step (S 200 ) may be a step in which pressing is performed on the pocket part  110   p  of the outer peripheral surface  110  of the battery case  100 . More specifically, the pressing step (S 200 ) can be performed by the above-mentioned first jig  310  and second jig  350 . Further, in the pressing step (S 200 ), the pressing and releasing of the first jig  310  and the second jig  350  to the pocket part  110   p  can be repeated at least once. 
     Thereby, in the battery cell manufacturing method according to an embodiment of the present disclosure, at least a part of the electrolyte contained in the pocket part  110   p  can move toward the inside of the battery case  100  by the pressing step (S 200 ). 
     As an example, the pressing step (S 200 ) may be repeated until the thickness of the pocket part  110   p  is similar to the thickness of the end part of the outer peripheral surface  110  of the battery case  100 . Here, the thickness of the end part of the outer peripheral surface  110  of the battery case  100  may mean the total thicknesses of the pouch film of the upper case and the pouch film of the lower case constituting the battery case  100 . However, the time point at which the repetition of the pressing step (S 200 ) ends is not limited thereto, and can be appropriately adjusted according to the production model and the process conditions of the battery cell  100 . 
     Thereby, in the battery cell manufacturing method according to an embodiment of the present disclosure, the pressing step (S 200 ) can be repeated until reaching the above-described thickness, and the electrolyte contained in the pocket part  110   p  can be sufficiently moved into the battery case  100 . That is, the electrolyte remaining in the pocket part  110   p  can be minimized, and the quality of the battery cell can also be further improved. 
     Further, referring to  FIGS.  4 ,  9 , and  10   , a sealing step (S 300 ) can be performed after the pressing step (S 200 ). Here, in the sealing step (S 300 ) may be a step in which at least a part of the pocket part  110   p  is heat-sealed by the above-mentioned sealing tool  500  to form the sealing part  150  on the outer peripheral surface of the battery case. 
     Thereby, in the battery cell manufacturing method according to an embodiment of the present disclosure, the sealing step (S 300 ) can heat-seal the pocket part  110   p  in a state in which the electrolyte contained in the pocket part  110   p  is minimized. That is, in the sealing step (S 300 ), the battery case  100  can be sealed with the sealing part  150  in a state in which the amount of electrolyte loss inside the battery case  100  is reduced, thereby further improving the quality of the battery cell. 
       FIG.  11    is a diagram showing a modification of the battery cell manufacturing device shown in  FIG.  5   . 
     Referring to  FIG.  11   , in the jig  300  of the present embodiment, at least one of the first jig  310  and the second jig  350  has a surface in contact with the pocket part  110   p  that is covered with a soft member  310 P. At this time, the bottom part of the soft member  310 P′ facing the pocket part  110   p  may have a structure in which the thickness changes. The soft member ( 310 P′) bottom part may have a first end part (P 1 ) and a second end part (P 2 ), and the thickness of the soft member  310 P′ increases as it goes from the first end part P 1  adjacent to the pre-sealing part  200  toward the second end part P 2  farther from the pre-sealing part  200  relative to the first end part P 1 . 
     By having a structure in which the thickness of the bottom portion of the soft member  310 P in contact with the pocket part  110   p  according to the present embodiment changes, in particular, a structure in which the thickness decreases as it moves away from the pre-sealing part  200 , the electrolyte can be moved much more efficiently toward the inside of the battery case  100  at the time of pressing the pocket part  110   p . Thereby, the electrolyte remaining in the pocket part  110   p  can be minimized, and the quality of the battery cell can be further improved. 
     Although the preferred embodiments of the present disclosure have been shown and described above, the scope of the present disclosure is not limited thereto, and numerous changes and modifications can be devised by those skilled in the art using the principles of the invention defined in the appended claims, which also falls within the spirit and scope of the present disclosure.  
     
       
         
           
               
               
             
               
                 Description of Reference Numerals 
               
             
            
               
                   100 : 
                 battery case 
               
               
                   110 : 
                 outer peripheral surface of battery case 
               
               
                   110   p : 
                 pocket part 
               
               
                   120 : 
                 pre-sealing part 
               
               
                   150 : 
                 sealing part 
               
               
                   300 : 
                 jig 
               
               
                   500 : 
                 sealing tool