Press molding apparatus and press molding method using same

Abstract

The present invention relates to a press molding apparatus and a press molding method using same. The technical problem to be solved is to provide a press molding method for solving a problem of, if a fracture surface is large during press molding of a cap plate, a welding defect rate increasing when the cap plate and a case are welded. To this end, the present invention provides a press molding apparatus and a press molding method using same, the press molding apparatus comprising: a die mold which is positioned on the lower portion of the press molding apparatus, is fixedly installed so as not to move, and has a workpiece provided at the upper portion thereof; and a punch mold which is positioned on the upper portion of the press molding apparatus, is installed to move with a predetermined gap, moves up and down to be inserted into the die mold, and pressurizes the workpiece provided on the upper portion of the die mold.

Description

Press mold device and press mold method using the same

[0001] The present invention relates to a press mold device and a press mold method using the same, and more particularly, to a press mold device that maintains an extremely small clearance and a press mold method using the same.

[0002]

[0003] Secondary batteries, unlike non-rechargeable primary batteries, are rechargeable and dischargeable. Low-capacity secondary batteries are used in small, portable electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for motor drives and power storage in hybrid and electric vehicles.

[0004] Typically, a secondary battery comprises an electrode assembly comprising a positive and negative electrode, a case housing the electrode assembly, and a cap assembly welded to the upper portion of the case. The cap assembly includes terminals connected to the electrode assembly, a vent for discharging gases generated within the case, and other features. The cap plate of this cap assembly is typically produced using a press molding method, which involves pressing and cutting a workpiece on a die with a punch.

[0005] The above-described information disclosed in the background technology of this invention is only intended to enhance understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0006]

[0007] The cap plate of the cap assembly of a secondary battery is produced by a press molding method. However, during the press molding process, the shear surface is cleanly sheared and the fracture surface is roughly fractured. If the fracture surface is large, the welding defect rate increases when welding the cap plate and the case. Therefore, a press molding method is proposed that maintains an extremely small clearance to minimize the fracture surface during the press molding process.

[0008] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0009]

[0010] According to one embodiment of the present invention for solving the above technical problem, a press mold device may include a die mold that is positioned at the bottom of the press mold device and is fixed so as not to move, and a workpiece is provided at the top; and a punch mold that is positioned at the top of the press mold device and is installed so as to move with a predetermined clearance, and is inserted into the die mold by moving up and down to press the workpiece provided at the top of the die mold.

[0011] And, a press mold method according to another embodiment of the present invention for solving the above technical problem may include the steps of: installing a die mold so as to be fixed so as not to move at the bottom of a press mold device; installing a punch mold so as to move with a predetermined clearance at the top of the press mold device; providing a workpiece at the top of the die mold; and moving the punch mold up and down to insert it into the die mold and pressurizing the workpiece provided at the top of the die mold.

[0012] According to another aspect of the present invention, a cap plate manufactured by a press mold method according to the present invention can be provided.

[0013] According to another aspect of the present invention, a secondary battery including the cap plate described above can be provided.

[0014] According to another aspect of the present invention, a vehicle including a secondary battery pack manufactured using a secondary battery having the above-described configuration can be provided.

[0015]

[0016] According to an embodiment of the present invention, by maintaining an extremely small clearance between a die mold and a punch mold, there is an effect of minimizing the fracture surface during press molding.

[0017] In addition, by minimizing the fracture surface during the press molding of the cap plate of the cap assembly of the secondary battery, there is an effect of reducing the welding defect rate during welding of the cap plate and the case.

[0018] By lowering the welding defect rate during welding of the cap plate and case in this way, process production loss due to defect improvement can be eliminated, and stabilization of mass production of secondary batteries and improvement of mold life can also be expected.

[0019] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0020]

[0021] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0022] Figure 1a is a top perspective view of a square secondary battery.

[0023] Figure 1b is a cross-sectional view II of Figure 1a.

[0024] FIG. 2a is a drawing illustrating an embodiment in which a cap plate and a case of a square secondary battery are combined.

[0025] Figure 2b is an enlarged cross-section of the welded portion of the cap plate and case of a square secondary battery.

[0026] Figure 3 is a drawing showing the structure of a conventional press mold device.

[0027] FIG. 4 is a drawing illustrating the structure of a press mold device according to one embodiment of the present invention.

[0028] FIG. 5 is a drawing illustrating an embodiment of a press mold device according to one embodiment of the present invention having a structure divided into a plurality of molds.

[0029] FIG. 6 is a drawing showing a state in which a punch mold of a press mold device according to one embodiment of the present invention partially presses a workpiece.

[0030] FIG. 7 is a drawing showing a blanking punch of a press mold device according to one embodiment of the present invention completely cutting a workpiece.

[0031] Figure 8 is a diagram showing experimental data of the ratio of the fracture surface to the shear surface according to the size of the clearance.

[0032] Figure 9 is a drawing showing the results of a comparative evaluation of the shear section and the fracture section according to the size of the clearance.

[0033] Figure 10 is a drawing showing the results of a comparative evaluation of the cross-section and fracture surface according to production volume.

[0034] FIG. 11 is an exemplary diagram of a secondary battery module in which secondary batteries including cap plates manufactured using a press mold device according to one embodiment of the present invention are arranged.

[0035] FIG. 12 is an example diagram of a secondary battery pack including the secondary battery module illustrated in FIG. 11.

[0036]

[0037] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of a term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as substitutes for them at the time of filing this application.

[0038] Additionally, when used herein, the terms "comprise", "include" and / or "comprising", "including" specify the presence of stated features, numbers, steps, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, elements and / or groups thereof.

[0039] Additionally, to facilitate understanding of the invention, the attached drawings may not be drawn to scale and some components may be exaggerated in size. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0040] The statement that two compared objects are "identical" means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may imply uniformity on average.

[0041] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0042] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0043] Any configuration being placed "on (or under)" or "above (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0044] Additionally, when a component is described as being "on," "connected to," or "coupled to" another component, it should be understood that the components may be directly connected or coupled to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through other components.

[0045] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, the use of "may" when describing embodiments of the present invention refers to "one or more embodiments of the present invention." Expressions such as "one or more" and "one or more" preceding a list of elements modify the list as a whole and do not modify individual elements within the list.

[0046] When reference is made throughout the specification to “A and / or B,” this means A, B, or A and B, unless otherwise stated, and when reference is made to “C through D,” this means C or more and D or less, unless otherwise stated.

[0047] When phrases such as "at least one of A, B, and C," "at least one of A, B, or C," "at least one selected from the group A, B, and C," or "at least one selected from A, B, and C," are used to specify a list of elements A, B, and C, the phrases can refer to any suitable combination.

[0048] The term "use" may be considered synonymous with the term "utilize." As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than degrees, and are intended to take into account inherent variations in measured or calculated values ​​that would be recognized by those skilled in the art.

[0049] Although terms such as first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or cross-section from another element, component, region, layer, or cross-section. Thus, a first element, component, region, layer, or section discussed below could also be termed a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0050] For ease of description, spatially relative terms such as "beneath," "below," "lower," "above," "upper," and the like may be used in the specification to describe the relationship of one element or feature to other element(s) or features as depicted in the drawings. It will be understood that spatially relative positions encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if the device in the drawings is turned over, other elements are understood to be "beneath" or "below," and the depicted elements are understood to be "above" or "above" other elements. Thus, the term "beneath" can encompass both the above and below orientations.

[0051] The terms used herein are for the purpose of describing embodiments of the invention and are not intended to limit the invention.

[0052]

[0053] Secondary batteries come in coin, cylindrical, square, and pouch shapes. Since the present invention is fundamentally applicable to square secondary batteries, a brief overview of square secondary batteries will be provided before describing embodiments of the present invention.

[0054] Figure 1a is a top perspective view of a square secondary battery, and Figure 1b is a cross-sectional view taken along line II' of Figure 1a.

[0055] First, the appearance of the square secondary battery illustrated in Fig. 1a is described.

[0056] The case (51) forms the overall appearance of the square secondary battery and may be formed of a conductive metal such as aluminum, an aluminum alloy, or nickel-plated steel. In addition, the case (51) may provide a space in which an electrode assembly is accommodated.

[0057] The cap assembly (60) may include a cap plate (61) covering the opening of the case (51), and the case (60) and the cap plate (61) may be made of a conductive material. Here, the first terminal (63) and the second terminal (62) may be installed to protrude outward by penetrating the cap plate (61) and being electrically connected to the positive or negative pole inside.

[0058] An electrolyte injection port (64) into which a sealing plug can be installed can be formed in the cap plate (61), and a vent (66) having a notch (65) formed therein can be installed. The vent (66) is for degassing gas generated inside the battery.

[0059] Referring to Fig. 1b, the internal structure of the square secondary battery and the bonding structure with the cap assembly (60) are described.

[0060] The square secondary battery illustrated in FIG. 1b may basically include an electrode assembly (40), a first current collector (41), a first terminal (62), a second current collector (42), a second terminal (63), and a cap assembly (60).

[0061] The electrode assembly (40) may be formed by winding or stacking a laminate of a first electrode plate, a separator, and a second electrode plate formed in a plate shape or a film shape. When the electrode assembly (40) is a rolled laminate, the winding axis may be parallel to the longitudinal direction of the case. In addition, the electrode assembly (40) may be a stack type rather than a rolled type, but the shape of the electrode assembly (40) is not limited in the present invention. In addition, the electrode assembly (40) may be a Z-stack electrode assembly in which the first electrode plate and the second electrode plate are inserted on both sides of a separator folded in a Z-stack shape. In addition, the electrode assembly (40) may be housed inside the case by stacking one or more electrode assemblies so that their long sides are adjacent to each other, and the number of electrode assemblies is not limited in the present invention. The first electrode plate of the electrode assembly (40) may function as a cathode and the second electrode plate may function as an anode, and vice versa.

[0062] The first electrode plate is formed by applying a first electrode active material such as graphite or carbon to a first electrode current collector plate formed of a metal foil such as copper, copper alloy, nickel or nickel alloy, and may include a first electrode tab (or first uncoated region) which is a region where the first electrode active material is not applied. The first electrode tab (43) may be a passage for current flow between the first electrode plate and the first current collector (41). In some examples, the first electrode tab (43) may be formed by cutting the first electrode plate in advance so as to protrude from one side when manufacturing the first electrode plate, and may protrude further from one side than the separator without separate cutting.

[0063] The second electrode plate is formed by applying a second electrode active material such as a transition metal oxide to a substrate formed of a metal foil such as aluminum or an aluminum alloy, and may include a second electrode tab (or second non-coated portion) (44) which is a region where the second electrode active material is not applied. The second electrode tab (44) may be a passage for current flow between the second electrode plate and the second current collector (42). In some examples, the second electrode tab (44) may be formed by cutting the second electrode plate in advance so as to protrude to the other side when manufacturing the second electrode plate, and may protrude further to the other side than the separator without separate cutting.

[0064] In some embodiments, the first electrode tab (43) may be positioned on the right side of the electrode assembly (40), and the second electrode tab (44) may be positioned on the left side of the electrode assembly (40), or may be positioned on one side in the same direction. Here, left and right are for convenience of explanation based on the secondary battery illustrated in FIG. 1, and their positions may change when the secondary battery rotates left and right or up and down.

[0065] The separator functions to prevent short circuiting between the first and second electrode plates while allowing the movement of lithium ions. The separator may be composed of, for example, a polyethylene film, a polypropylene film, a polyethylene-polypropylene film, or the like.

[0066] A first electrode tab (43) of the first electrode plate and a second electrode tab (44) of the second electrode plate extend from both ends of the electrode assembly (40) as described above. In some embodiments, the electrode assembly (40) may be accommodated in a case (51) together with an electrolyte.

[0067] In the above electrode assembly (40), the first electrode tabs (43) and the second electrode tabs (44) extending from the first electrode plate and the second electrode plate to both sides are respectively connected by welding to the first current collector (41) and the second current collector (42).

[0068] The first collector (41) and the second collector (42) are connected to the first terminal (62) and the second terminal (63) described in Fig. 2a, respectively, through a terminal pin (67). In some embodiments, the outer surface of the terminal pin (67) may be threaded and may be fastened to the first terminal (62) and the second terminal (63) through a screw connection. However, the present invention is not limited thereto, and the terminal pin (67) may be fastened to the first terminal (62) and the second terminal (63) by riveting or welding.

[0069]

[0070] Fig. 2a is a drawing showing an example in which a cap plate and a case of a square secondary battery are combined, and Fig. 2b is an enlarged drawing of a cross-section of a welded portion of a cap plate and a case of a square secondary battery.

[0071] Referring to FIGS. 2A and 2B, the cap plate (61) of the cap assembly (60) of the square secondary battery is joined to the upper part of the case (51) by welding. Welding is a method of joining the same or different types of metal materials by applying heat and pressure to form a direct bond between solids. The cap plate (61) is generally produced by a press molding method in which a workpiece on a die is cut by pressing it with a punch. At this time, the press molding has a shear surface that is cleanly sheared and a fracture surface that is roughly broken. The fracture surface corresponds to the cross-section when the material is broken or cut by bending or pulling, and the fracture surface of the cap plate (61) increases the defect rate during welding with the case (51) due to the rough surface. In fact, it has been shown that there is a correlation between the size of the width of the fracture surface and the defect rate in welding between the cap plate and the case. Therefore, the present invention aims to minimize the fracture surface of the cap plate (61) through a press molding device and a press molding method using the same according to an embodiment of the present invention.

[0072]

[0073] Figure 3 is a drawing showing the structure of a conventional press mold device.

[0074] Referring to FIG. 3, a conventional press mold device includes a die mold (10) having a workpiece (1) provided on the upper portion, a punch mold (20) that moves up and down and is inserted into the die mold (10) to press the workpiece (1) provided on the upper portion of the die mold (10), and an outer guide post (30) that guides the die mold (10) and the punch mold (20).

[0075] At this time, the die mold (10) includes a die plate (11) and a die holder (12) that fixes the die plate (11).

[0076] In addition, the punch mold (20) includes a punch holder (21), a punch plate (22), a back plate (23), and an inner guide post (24) that is fixed to the punch holder (21) and installed by penetrating the punch plate (22) and the back plate (23). In a conventional press mold device, the play (A') between the punch plate (22) and the back plate (23) and the inner guide post (24) is almost non-existent, that is, 7 to 8 μm, so that the punch plate (22) and the back plate (23) are fixed to the inner guide post (24).

[0077] It is generally known that if the clearance between the die mold (10) and the punch mold (20) is made extremely small, the size of the fracture surface can be reduced by the phenomenon in which the configuration of the cross-section is formed in the first and second stages.

[0078] According to the conventional press mold device illustrated in FIG. 3, when both the die mold (10) and the punch mold (20) are fixed, if the clearance between the die mold (10) and the punch mold (20) is not accurately adjusted, the punch mold (20) cannot pass through the die mold (10). Therefore, the clearance between the die mold (10) and the punch mold (20) must be determined, but it is very difficult to accurately adjust it, so it is inevitable to artificially leave some margin in the clearance, making it difficult to make the clearance very small.

[0079] Referring to FIG. 4 below, a press mold device according to one embodiment of the present invention that can minimize the fracture surface by making the clearance very small will be described.

[0080]

[0081] FIG. 4 is a drawing illustrating the structure of a press mold device according to one embodiment of the present invention.

[0082] Referring to FIG. 4, a press mold device (100) according to one embodiment of the present invention includes a die mold (110) that is positioned at the bottom of the press mold device and fixedly installed so as not to move, and a workpiece (1) provided at the top thereof, and a punch mold (120) that is positioned at the top of the press mold device (100) and installed so as to move with a predetermined clearance, and is inserted into the die mold (110) so as to move up and down to press the workpiece (1) provided at the top of the die mold (110).

[0083] The difference between the press mold device (100) illustrated in FIG. 4 and the conventional press mold device illustrated in FIG. 3 is that the die mold (110) is installed in a fixed manner, and the punch mold (120) is installed to move with a predetermined clearance. In the press mold device (100) according to one embodiment of the present invention, since the punch mold (120) has a predetermined clearance, it moves downwards, finds its own center when the workpiece (1) is pressed, and is inserted into the die mold (110).

[0084] In the case of a conventional press mold device, since the punch mold (20) is fixed, if the clearance is made very small, it is very difficult to align the center, and if the center is slightly off, the punch mold (20) cannot be inserted into the die mold (10). In contrast, in the press mold device (100) according to an embodiment of the present invention, since the punch mold (120) can move within a predetermined range of play, even if it moves downward with a slight center off, the punch mold (20) finds the center by itself and is inserted into the die mold (10). Therefore, the press mold device (100) according to an embodiment of the present invention can make the clearance very small. In one embodiment, the clearance between the punch mold (120) and the die mold (110) of the press mold device (100) according to an embodiment of the present invention may be 0.5% or less of the thickness of the workpiece (1).

[0085] A die mold (110) of a press mold device (100) according to one embodiment of the present invention includes a die plate (111) and a die holder (112) that fixes the die plate (111). In one embodiment, both the die plate (111) and the die holder (112) can be fixed.

[0086] A punch mold (120) of a press mold device (100) according to one embodiment of the present invention includes a punch holder (121), a punch plate (122) that directly presses a workpiece (1), a back plate (123) installed at the rear end of the punch plate (122), and an inner guide post (124) that is fixed to the punch holder (121) and installed to penetrate the punch plate (122) and the back plate (123). At this time, a predetermined clearance (B') exists between the punch plate (122) and the back plate (123) and the inner guide post (124). Here, the predetermined clearance (B') is intended to allow the punch plate (122) and the back plate (123) to move around the inner guide post (124) without being fixed to the inner guide post (124), and may be about 50 μm. The punch mold (120) of the press mold device (100) according to one embodiment of the present invention has such a structure that it can move with a predetermined clearance when moving up and down, and can be inserted into the die mold (110) by finding the center even if the clearance is very small.

[0087] The outer guide post (130) serves to guide the die mold (10) and punch mold (20) by fixing the die holder (112) and the punch holder (121).

[0088] The press mold device (100) according to one embodiment of the present invention can minimize the fracture surface by making the clearance very small. Accordingly, the cap plate (61) produced by the press mold device (100) according to one embodiment of the present invention can have a minimized fracture surface, thereby reducing the defect rate when welding the cap plate (61) and the case (51).

[0089]

[0090] FIG. 5 is a drawing illustrating an embodiment of a press mold device according to one embodiment of the present invention having a structure divided into a plurality of molds.

[0091] Referring to FIG. 5, a press mold device according to an embodiment of the present invention may have a structure (1000) divided into a plurality of molds. This may be used in a progressive mold that enables a plurality of processing processes to be sequentially performed while transporting a workpiece (1). Generally, a progressive mold is performed as an integrated mold, but the press mold device according to an embodiment of the present invention has a structure (1000) divided into a plurality of molds, so that a user can freely perform a processing process by adding, changing, or removing a mold for a desired process.

[0092] In one embodiment, the molds 1 to 10 in FIG. 5 may be conventional molds such as lower die forging, piercing, upper die forging, and chamfering. The die mold (110) and the punch mold (120) of the press mold device (100) according to one embodiment of the present invention may be positioned at mold No. 11. The die mold (110) and the punch mold (120) of the press mold device (100) according to one embodiment of the present invention may pressurize the workpiece (1) to cut the workpiece (1) at once, or may pressurize it partially and then cut it in the next mold. This will be described with reference to FIGS. 6 and 7.

[0093]

[0094] FIG. 6 is a drawing showing a state in which a punch mold of a press mold device according to one embodiment of the present invention partially presses a workpiece.

[0095] Referring to FIG. 6, the punch mold (120) of the press mold device (100) according to one embodiment of the present invention can partially pressurize the workpiece (1). In one embodiment, the punch mold (120) can pressurize the workpiece (1) to 90% or more and less than 100% of the thickness of the workpiece (1). The reason for partially pressing the workpiece (1) in this way is that when the workpiece (1) is thick, for example, 3 mm or more, it is not easy for the punch mold (120) of the press mold device (100) according to one embodiment of the present invention to cut the workpiece (1) at once, and if it is forced to cut at once, a large fracture surface may be generated.

[0096]

[0097] FIG. 7 is a drawing showing a blanking punch of a press mold device according to one embodiment of the present invention completely cutting a workpiece.

[0098] Referring to FIG. 7, a press mold device (100) according to one embodiment of the present invention may further include a blanking punch (120') that pressurizes and completely cuts a workpiece (1) that is pressed to 90% or more and less than 100% of the thickness of the workpiece. FIG. 7 illustrates a workpiece (1) that is completely cut by a blanking punch (120'). In one embodiment, since the blanking punch (120') only needs to perform a cutting operation, it may be fixed, unlike the punch mold (120), and since there is no need to reduce the clearance, the size of the pressing surface of the blanking punch (120') may be smaller than the size of the pressing surface of the punch mold.

[0099] Returning to FIG. 5 again, in the structure (1000) divided into a plurality of molds, the blanking punch (120') may be included in the last mold among the plurality of molds, i.e., mold number 12, and the punch mold (120) may be included in the mold preceding the last mold, i.e., mold number 11.

[0100]

[0101] Figure 8 is a diagram showing experimental data of the ratio of the fracture surface to the shear surface according to the size of the clearance.

[0102] Referring to Fig. 8, when the clearance between the die mold and the punch mold is 0.01 mm, the fracture surface is large, at 70% to 80% of the shear surface, whereas as the clearance decreases, the fracture surface gradually decreases, and when the clearance is made extremely small, at 0.003 mm, i.e., 3 μm, the fracture surface becomes very small, at 0 to 5%.

[0103] As previously discussed, in the press mold device (100) according to one embodiment of the present invention, since the punch mold (120) can move within a predetermined range of clearance, even if it moves downward with a slight misalignment of the center, the punch mold (20) finds its own center and is inserted into the die mold (10). Accordingly, the press mold device (100) according to one embodiment of the present invention can make the clearance very small.

[0104]

[0105] Figure 9 is a drawing showing the results of a comparative evaluation of the shear section and the fracture section according to the size of the clearance.

[0106] Referring to Fig. 9, when the clearance was 0.04 mm, the first shear surface was 0.878 mm and the fracture surface was 0.918. When the clearance was 0.003 mm, the first shear surface increased to 1.643 mm, showing an improvement effect of 0.765 mm, and the fracture surface decreased to 0.137, showing an improvement effect of 0.781 mm. In addition, when the clearance was 0.04 mm, it was confirmed that the second shear surface partially had a mixed shape of the shear surface and the fracture surface, but when the clearance was 0.003 mm, a mixed shape of the shear surface and the fracture surface occurred overall.

[0107]

[0108] Figure 10 is a drawing showing the results of a comparative evaluation of the cross-section and fracture surface according to production volume.

[0109] Referring to FIG. 10, when comparing the results of producing 100 (0.1K), 5,000 (5.0K), and 10,000 (10.0K) pieces with a clearance of 0.003 mm, it can be seen that there is almost no difference in the shear surface and the fracture surface, so that even if cap plates are mass-produced through the press mold device (100) according to one embodiment of the present invention, cap plates with almost no difference in quality can be produced.

[0110]

[0111] A press mold method using a press mold device (100) having the same structure as described above is described.

[0112] According to one embodiment of the press mold method, a die mold (110) is installed so as to be fixed so as not to move at the bottom of a press mold device (100), and a punch mold (120) is installed so as to move with a predetermined clearance at the top of the press mold device (100). At this time, a clearance between the punch mold (120) and the die mold (110) may be 0.5% or less of the thickness of the workpiece (1). Then, the workpiece (1) is provided at the top of the die mold (110). Then, the punch mold (120) is moved up and down and inserted into the die mold (110) to press the workpiece (1) provided at the top of the die mold (110).

[0113] In one embodiment, the workpiece (1) is pressed to a thickness of 90% or more and less than 100% of the thickness of the workpiece (1), and a blanking punch is provided so that the workpiece (1) pressed to a thickness of 90% or more and less than 100% of the thickness of the workpiece (1) can be completely cut. At this time, the size of the pressing surface of the blanking punch may be smaller than the size of the pressing surface of the punch mold.

[0114]

[0115] As described above, the press mold device (100) according to one embodiment of the present invention can be used to manufacture a cap plate (61), and the cap plate (61) manufactured in this way can have a minimized fracture surface, thereby reducing the defect rate when welding the cap plate (61) and the case (51). Accordingly, the secondary battery including the cap plate (61) manufactured by the press mold device (100) according to one embodiment of the present invention can prevent liquid or gas such as an internal electrolyte from leaking due to a strong weld joint between the cap plate (61) and the case (51), thereby improving safety.

[0116]

[0117] Hereinafter, a material that can be used in a secondary battery including a cap plate manufactured using a press mold device according to the present invention will be described.

[0118] A compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) can be used as a cathode active material. Specifically, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0119] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0120] As an example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c About 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c About 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0121] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al, or a combination thereof.

[0122] A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0123] The content of the positive electrode active material may be 90 wt% to 99.5 wt% with respect to 100 wt% of the positive electrode active material layer, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0124] The above-mentioned collector may be made of Al, but is not limited thereto.

[0125] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0126] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0127] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiOx (0 <x<2), Si계 합금, 또는 이들의 조합일 수 있다.

[0128] The above silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0129] The silicon-carbon composite may further comprise crystalline carbon. For example, the silicon-carbon composite may comprise a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core.

[0130] A negative electrode for a lithium secondary battery includes a current collector and a negative electrode active material layer positioned on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder and / or a conductive material.

[0131] For example, the negative electrode active material layer may include 90 to 99 wt% of the negative electrode active material, 0.5 to 5 wt% of the binder, and 0 to 5 wt% of the conductive material.

[0132] The above binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof. When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0133] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0134] An electrolyte for a lithium secondary battery contains a non-aqueous organic solvent and a lithium salt.

[0135] The above non-aqueous organic solvent acts as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0136] The above non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof, and may be used alone or in combination of two or more thereof.

[0137] Additionally, when using a carbonate solvent, a mixture of cyclic carbonate and chain carbonate can be used.

[0138] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. Such separators may be polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film comprising two or more layers of these materials.

[0139] The separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof, positioned on one or both sides of the porous substrate.

[0140] The above organic material may include a polyvinylidene fluoride-based antibody or a (meth)acrylic polymer.

[0141] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include inorganic particles selected from, but not limited to, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0142] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0143]

[0144] FIG. 11 is an exemplary diagram of a secondary battery module in which secondary batteries including cap plates manufactured using a press mold device according to one embodiment of the present invention are arranged.

[0145] Referring to FIG. 11, a secondary battery module is illustrated in which secondary batteries are arranged, including a cap plate (61) manufactured using a press mold device (100) according to one embodiment of the present invention. In accordance with the need for high capacity secondary batteries for driving electric vehicles, a secondary battery module is manufactured by arranging and connecting a plurality of secondary battery cells in a horizontal and / or vertical direction.

[0146] A plurality of secondary batteries are arranged in a space formed by a pair of opposing end plates (71a, 71b) and a pair of opposing side plates (72a, 72b). The arrangement of the secondary batteries can be designed in terms of arrangement direction and number to obtain desired voltage and current specifications.

[0147]

[0148] FIG. 12 is an example diagram of a secondary battery pack (80) configured to apply the secondary battery module illustrated in FIG. 11 to an actual product (e.g., an automobile).

[0149] A secondary battery pack can be manufactured by embedding multiple secondary battery modules into a pack housing designed to be installed in an actual product. The pack housing may include fasteners and electrical connectors necessary for installation in the product. For convenience of illustration, related components such as bus bars for electrical connection between the secondary batteries, a cooling unit, and external terminals are omitted in Figure 12.

[0150]

[0151] Secondary battery packs can be installed in automobiles. Examples of automobiles include electric vehicles, hybrid vehicles, or plug-in hybrid vehicles. Automobiles include four-wheel drive or two-wheel drive vehicles.

[0152]

[0153] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. In the press mold device, A die mold which is installed so as to be fixed and not to move at the bottom of the above press mold device, and in which a workpiece is provided at the top; and A press mold device characterized by including a punch mold that is positioned on the upper part of the press mold device and is installed to move with a predetermined clearance, and moves up and down to be inserted into the die mold and pressurize the workpiece provided on the upper part of the die mold.

2. In paragraph 1, A press mold device characterized in that the clearance between the punch mold and the die mold is 0.5% or less of the thickness of the workpiece.

3. In paragraph 1, The above punch mold is, punch holder; A punch plate that directly applies pressure to the above-mentioned processing material; A back plate installed at the rear end of the punch plate; and Including an inner guide post fixed to the punch holder and installed through the punch plate and back plate, A press mold device characterized in that a predetermined clearance exists between the punch plate, the back plate, and the inner guide post.

4. In paragraph 1, The above punch mold is, A press mold device characterized in that it pressurizes the above-mentioned workpiece to a thickness of 90% or more and less than 100% of the thickness of the above-mentioned workpiece.

5. In paragraph 4, A press mold device characterized in that it further includes a blanking punch that completely cuts the workpiece by pressing the workpiece to a thickness of 90% or more and less than 100% of the thickness of the workpiece.

6. In paragraph 5, A press mold device characterized in that the size of the pressing surface of the blanking punch is smaller than the size of the pressing surface of the punch mold.

7. In paragraph 5, The above press mold device, It has a structure divided into multiple molds, The above blanking punch is included in the last mold among the plurality of molds, A press mold device characterized in that the punch mold is included in the mold preceding the last mold.

8. A step of installing a die mold so that it is fixed so as not to move at the bottom of the press mold device; A step of installing a punch mold so as to move with a predetermined clearance on the upper part of the press mold device; A step of providing a processing material on the upper part of the die mold; and A press mold method characterized by including a step of moving the punch mold up and down and inserting it into the die mold to pressurize the workpiece provided on the upper portion of the die mold.

9. In paragraph 8, A press mold method, characterized in that the clearance between the punch mold and the die mold is 0.5% or less of the thickness of the workpiece.

10. In paragraph 8, The step of pressurizing the above-mentioned processed material is: A press mold method characterized by including a step of pressurizing the above-mentioned workpiece to a thickness of 90% or more and less than 100% of the thickness of the above-mentioned workpiece.

11. In paragraph 10, Step of providing a blanking punch; A press mold method characterized by including a step of completely cutting the workpiece by pressing the workpiece to a thickness of 90% or more and less than 100% of the thickness of the workpiece through the blanking punch.

12. In paragraph 11, A press mold method, characterized in that the size of the pressing surface of the blanking punch is smaller than the size of the pressing surface of the punch mold.

13. A cap plate manufactured by the method described in any one of claims 8 to 12.

14. A secondary battery comprising the cap plate described in Article 13.

15. In paragraph 14, A secondary battery characterized by its square shape.

16. A vehicle including a secondary battery as described in Article 14.

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