KR101030835B1 - Method of manufacturing case for battery and case for battery manufactured by the same - Google Patents

Abstract

According to the present invention, the first side wall portion and the second side wall portion having different thicknesses are simultaneously formed without additional dies and punches by a drawing process using a die and a punch having an inclined surface. The present invention relates to a method for manufacturing a battery case capable of reducing a drawing process and a battery case manufactured thereby.

To this end, the method for manufacturing a battery case according to the present invention comprises a case material preparation step of preparing a case material; A first sidewall portion having a first thickness and a first sidewall portion which is bent and extended to the bottom portion by carrying out a drawing process such that the case material extends along a central axis, the sidewall portion being bent and extending from the bottom portion; A stepped portion extending obliquely at an end of the first sidewall portion so as to move away from the first sidewall portion by being bent from the stepped portion so as to be parallel to the first sidewall portion and having a second thickness thicker than the first sidewall portion; A columnar container forming step of forming a columnar container to include a second sidewall portion projecting outwardly from the central axis; And performing a drawing process such that an inner surface of the second sidewall portion protrudes in the central axis direction relative to the first sidewall portion to deform the stepped container and the second sidewall portion in the central axis direction. In the forming of the columnar container, the first sidewall part and the second sidewall part may be simultaneously formed in the sidewall part by using a die and a punch having an inclined surface.

Die, punch, drawing, thickness, case

Description

Method of manufacturing a battery case and a battery case manufactured by the same {Method of manufacturing case for battery and case for battery manufactured by the same}

According to the present invention, the first side wall portion and the second side wall portion having different thicknesses are simultaneously formed without additional dies and punches by a drawing process using a die and a punch having an inclined surface. The present invention relates to a method for manufacturing a battery case capable of reducing a drawing process and a battery case manufactured thereby.

In general, a rechargeable battery refers to a battery that can be charged and discharged, unlike a primary battery that is not rechargeable, and is widely used in advanced electronic devices such as a cellular phone, a notebook computer, and a camcorder. In particular, lithium secondary batteries have an operating voltage of 3.6V, which is three times higher than nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as electronic equipment power sources, and are rapidly increasing in terms of high energy density per unit weight.

Such lithium secondary batteries mainly use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials. Moreover, although a lithium secondary battery is manufactured in various shapes, typical shapes include cylindrical shape, square shape, and pouch type.

Among these, the cylindrical secondary battery includes an electrode assembly, a cylindrical case accommodating the electrode assembly, and a cap assembly coupled to the upper portion of the case.

The electrode assembly has a cathode and a cathode, and a separator interposed between the two electrodes is wound in a cylindrical shape to form a jelly roll, and the positive and negative electrode tabs are drawn out from the positive and negative electrodes, respectively. Normally, the positive electrode tab is upward and the negative electrode tab is pulled out downward.

The case is a metal container having a substantially cylindrical shape in a cylindrical secondary battery, and is formed by a processing method such as deep drawing. Therefore, it is also possible that the case itself serves as a terminal.

The cap assembly is coupled to the open top of the case, with a gasket insulated between the cap assembly and the case. The cap assembly may include several component elements, such as safety vents, current blocking means, PTCs, and cap ups.

On the other hand, in order to increase the capacity of the battery while at the same time increasing the strength of the part where the case, gasket and cap assemblies are in contact, the thickness of the upper part of the side wall of the case is thinner except the upper part of the side wall of the case. There is a trend to manufacture cases.

By the way, in order to thicken the upper end part of the side wall of a case and to thin the part except the upper end part of a case side wall, the deep drawing process using many die and punch is performed many times. Accordingly, there is a problem that the manufacturing process of the secondary battery is increased and the manufacturing time of the secondary battery is long.

SUMMARY OF THE INVENTION An object of the present invention is to simultaneously form the first sidewall portion and the second sidewall portion having different thicknesses without additional dies and punches by a drawing process using a die and a punch having an inclined surface, without additional dies and punches. The present invention provides a method for manufacturing a battery case that can reduce the drawing process according to the present invention, and a battery case manufactured thereby.

In order to achieve the above object, a manufacturing method of a battery case according to an embodiment of the present invention comprises the case material preparation step of preparing a case material; A first sidewall portion having a first thickness and a first sidewall portion which is bent and extended to the bottom portion by carrying out a drawing process such that the case material extends along a central axis, the sidewall portion being bent and extending from the bottom portion; A stepped portion extending obliquely at an end of the first sidewall portion so as to move away from the first sidewall portion by being bent from the stepped portion so as to be parallel to the first sidewall portion and having a second thickness thicker than the first sidewall portion; A columnar container forming step of forming a columnar container to include a second sidewall portion projecting outwardly from the central axis; And performing a drawing process such that an inner surface of the second sidewall portion protrudes in the central axis direction relative to the first sidewall portion to deform the stepped container and the second sidewall portion in the central axis direction. In the forming of the columnar container, the first sidewall part and the second sidewall part may be simultaneously formed in the sidewall part by using a die and a punch having an inclined surface.

The forming of the columnar container may include forming a columnar container having a first height from the case material by performing a drawing process using a cup-shaped first die having a first depth and a first punch.

In the forming of the columnar container, a drawing process using a cup-shaped second die and a second punch having a second depth deeper than the first depth is performed, so that the columnar container having the first height has a second height. The method may further include forming a columnar container.

The second die has a second die bottom bottomed from the inside; A second die side surface connected perpendicular to the second die bottom surface; A second die inclined surface inclinedly connected to the second die side to be farther from the central axis than the distance between the second die side; And a second connection surface connected to the second die inclined surface parallel to the second die side.

The second punch has a bottom from the outside and a second punch bottom parallel to the second die bottom; A second punch side surface perpendicular to the second punch bottom surface and parallel to the second die side surface; A second punch inclined surface connected to the second punch side and parallel to a second die inclined surface; And a second punch connection surface connected to the second punch inclined surface so as to be parallel to the second punch side surface.

The vertical distance between the second die side and the second die connecting surface may be greater than the first thickness.

In the forming of the columnar container, the distance between the inner surface of the first side wall portion and the central axis may be shorter than the distance between the inner surface of the second side wall portion and the central axis.

In the deforming of the columnar container, a drawing process using a third die having a cup shape and a third punch having the second depth is performed, and the distance between the central axis and the outer surface of the first sidewall portion, the central axis, and the The distance between the outer surfaces of the two side wall portions can be the same.

The third die may include a third bottom surface that forms a bottom from the inside and a third die side surface that is perpendicularly connected to the third bottom surface.

The third punch has a bottom from the outside and a third punch bottom parallel to the third die bottom; And a third punch side surface connected perpendicular to the third punch bottom surface and parallel to the third die side surface.

In the columnar container deformation step, the distance between the inner surface of the first side wall portion and the central axis may be longer than the distance between the inner surface of the second side wall portion and the central axis.

In addition, the columnar container deformation step uses a cup-shaped fourth die and a fourth punch having the second depth before drawing with respect to the columnar container using the third die and the third punch. It may include a step of performing an auxiliary drawing process for the columnar container.

The fourth die has a fourth die bottom bottomed from the inside; A fourth die sidewall connected perpendicularly to the fourth die; And inclinedly connected to the fourth die side to be farther from the central axis than the distance between the fourth die side, and than an outer angle of the first sidewall portion and the stepped portion formed by the drawing process using the second die and the second punch, The fourth die may include a fourth die inclined surface inclined such that an outer angle of the first sidewall portion and the stepped portion formed by the drawing process using the fourth die and the fourth punch is increased.

The fourth punch has a bottom from the outside and a fourth punch bottom parallel to the fourth die bottom; A fourth punch side surface connected perpendicular to the fourth punch bottom surface and parallel to the fourth die side surface; And a fourth die inclined surface connected to the fourth punch side surface and parallel to the fourth die inclined surface.

By the method for manufacturing a battery case as described above, a battery case which can increase the bonding strength with other components while increasing the capacity of the battery can be produced.

In the manufacturing method of the battery case according to the embodiment of the present invention, the first side wall portion and the second side wall portion having different thicknesses from the side wall portion of the battery case by a drawing process using a die and a punch having an inclined surface without additional die and punch It can be formed at the same time. Accordingly, the manufacturing method of the battery case according to the embodiment of the present invention can reduce the manufacturing process according to the additional die and punch, it is possible to reduce the manufacturing process and manufacturing time of the secondary battery.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a flowchart illustrating a method of manufacturing a battery case according to an exemplary embodiment of the present invention, and FIGS. 2A to 2C are cross-sectional views illustrating a method of manufacturing the battery case of FIG. 1.

Referring to FIG. 1, the method for manufacturing a battery case according to an embodiment of the present invention includes a case material preparing step S1, a columnar container forming step S2, and a columnar container deformation step S3.

First, referring to FIG. 2A, the case material preparation step S1 is a step of preparing the case material 10.

The case material 10 may be prepared in a substantially plate form so as to form a columnar container by drawing. The case material 10 may be formed of a metal material, for example, aluminum and an aluminum alloy, so that the finished battery case has polarity. In the embodiment of the present invention, the planar shape of the case material 10 is formed in a circular shape, so that the battery case of the cylindrical secondary battery will be described as an example. In FIGS. 2A to 2D, since the plate-like case material 10 and the finished battery case 11 have a symmetrical shape with respect to the central axis C, only a portion on the left side from the central axis C is displayed. It was.

Next, referring to FIGS. 2B and 2C, the columnar container forming step S2 may be performed by a drawing process such that the case material 10 extends along the central axis C, thereby providing a bottom portion 12. And a columnar container 11 having sidewalls 13.

Specifically, the columnar container forming step S2 may be performed after disposing the case material 10 between the cup-shaped first die 1 having the first depth D1 and the first punch 2. As shown in FIG. 2B, the punch 2 is moved downward relative to the first die 1. The case material 10 is then transformed into a columnar container 11 having a first height H1 and having a bottom portion 12 and a side wall portion 13. Here, the first depth D1 of the first die 1 is made low, so that the case material 10 is not stretched long along the central axis C by force. Subsequently, the columnar container forming step S2 moves the first punch 2 upward with respect to the first die 1, and has a columnar container 11 having the first height H1. Is removed from the first die 1.

The columnar container forming step S2 then has a first height H1 of FIG. 2B between the cup-shaped second die 3 and the second punch 4 having a second depth D2. After arranging the columnar container 11, the second punch 4 is moved downward with respect to the second die 3 as shown in FIG. 2C. Then, the columnar container 11 having the first height H1 is further extended in the vertical direction to be transformed into the columnar container 11 having the second height H2. Here, the side wall portion 13 of the columnar container 11 having the second height H2 is bent to the bottom portion 12 and extends, and the first side wall portion 13a having the first thickness T1. ), A stepped portion 13b extending inclined at an end of the first sidewall portion 13a away from the central axis C, and bent from the stepped portion 13b in parallel with the first sidewall portion 13a. And a second sidewall portion 13c protruding outward from the central axis C relative to the first sidewall portion 13a to have a second thickness T2 thicker than the first thickness T1. Is formed. In addition, the side wall portion 13 of the columnar container 11 having the second height H2 further includes a cutting portion 13d extending from the second side wall portion 13 and cut in a subsequent process. Can be formed. Here, the distance R1 between the inner surface of the first side wall portion 13a of the side wall portion 13 and the central axis C is between the inner surface of the second side wall portion 13c and the central axis C. Is shorter than the distance R2. Meanwhile, an outer angle formed by the first sidewall portion 13a and the stepped portion 13b will be defined as θ1.

Looking specifically at the second die 3 and the second punch 4 used to form the columnar container 11 having the second height H2, the second die 3 is inward. And a second die bottom surface 3a, a second die side surface 3b, a second die inclined surface 3c, and the second die connecting surface 3d formed therein, and the second punch 4 A second punch bottom surface 4a, a second punch side surface 4b, the second punch inclined surface 4c, and the second punch connection surface 4d are formed on the outside.

The second die bottom 3a bottoms inside the second die 3. The second die side 3b is connected perpendicularly to the second die bottom 3a. The second die inclined surface 3c is connected to the second die side 3b and is formed to be inclined further away from the distance between the central die C and the second die side 3b. The second die connecting surface 3d is connected with the second die inclined surface 3c so as to be parallel to the second die side surface 3b. In addition, a distance L1 vertically connecting the second die side surface 3b and the second die connecting surface 3d may be greater than the first thickness T1. This means that if the distance L1 is smaller than the first thickness T1, a second thicker sidewall portion 13 of the columnar container 11 having the second height H2 is thicker than the first thickness T1. This is because the second thickness T2 of the side wall portion 13c cannot be formed. Meanwhile, the distance L2 vertically connecting the second punch side surface 4b of the second punch 4 corresponding to the second die 3 and the second punch connection surface 4d is also equal to the first thickness ( It can be made larger than T1).

The second punch bottom face 4a forms a bottom on the outside of the second punch 4 and is parallel to the second die bottom face 3a. The second punch side 4b is connected perpendicular to the second punch bottom 4a and is parallel to the second die side 3b. The second punch inclined surface 4c is connected to the second punch side 4b, and is inclined to be further away from the center axis C than the distance between the second punch side 4b (ie, the second die inclined surface Parallel to (3c)). The second punch connection surface 4d is connected with the second punch inclined surface 4c so as to be parallel to the second punch side surface 4b.

As described above, the columnar container forming step S2 includes drawing using a second die 3 including a second die inclined surface 3c and a second punch 4 including a second punch inclined surface 4c. By the process, the first side wall portion 13a having the first thickness T1 and the second thickness T2 different from each other in the side wall portion 13 of the columnar container 11 having the second height H2 and The second sidewall portion 13c can be formed simultaneously without additional die and punch.

Thereafter, the columnar container forming step S2 moves the second punch 4 upward with respect to the second die 3, and has a columnar container 11 having the second height H2. ) Is taken out from the second die 3.

Next, referring to FIG. 2D, the columnar container deformation step S3 is such that an inner surface of the second sidewall portion 13c projects in the direction of the central axis C rather than the first sidewall portion 13a. It is a step of pushing the step portion 13b and the second side wall portion 13c in the direction of the central axis C by using.

Specifically, the columnar container deformation step S3 places the columnar container 11 of FIG. 2C between the cup-shaped third die 5 and the third punch 6 having the second depth D2. Then, as shown in FIG. 2D, the third punch 6 is moved downward with respect to the third die 5. Then, the columnar container 11 of FIG. 2C is transformed into the columnar container 11 including the step part 13b and the 2nd side wall part 13c which protruded in the said central axis C direction.

The third die 5 and the third punch 6 used to form the stepped portion 13b and the second side wall portion 13c protruding from the columnar container 11 in the direction of the central axis C. Specifically, the third die 5 includes a third die bottom surface 5a and a third die side surface 5b formed on the inner side, and the third punch 6 is formed on the outer side. And a third punch bottom face 6a and a third punch side face 3b.

The third die bottom 5a bottoms inside the third die 5. The third die side 5b is connected perpendicular to the third die bottom 5a.

The third punch bottom 6a forms a bottom outside the third punch 6 and is parallel to the third die bottom 5a. The third punch side 6b is connected perpendicular to the third punch bottom 6a and is parallel to the third die side 5b.

Thus, the columnar container deformation step S3 uses a third die 5 comprising a third die side 5b and a third punch 6 comprising a third punch side 6b, In the columnar container 11, the center axis C is opposed to the step portion 13b and the second side wall portion 13c protruding outward from the central axis C in comparison with the first side wall portion 13a. Push in to project. In other words, the columnar container forming step S3 is a distance between the central axis C and the outer surface of the first sidewall portion 13a and the outer surface of the central axis C and the second sidewall portion 13c. The distance between them is equal to R3. Subsequently, the columnar container forming step S3 moves the third punch 6 upward with respect to the third die 5 and moves the columnar container 11 of FIG. 2D into the third die ( 5) Take out from

In addition, although not shown, the columnar container deformation step S3 includes a process of cutting the cutting portion 13d. Through this process, a battery case 11 (see FIG. 3) in which the cutting portion 13d is cut from the side wall portion 13 is manufactured.

As described above, the method for manufacturing a battery case according to an embodiment of the present invention, the second die 3 and the second punch inclined surface 4c having the second die inclined surface 3c in the columnar container forming step S2. The first side wall portion 13a having the first thickness T1 and the second thickness T2 differing from each other in the side wall portion 13 of the battery case 11 by a drawing process using the second punch 4 having a diameter. ) And the second sidewall portion 13c can be formed simultaneously without additional die and punch. Accordingly, the manufacturing method of the battery case according to an embodiment of the present invention can reduce the manufacturing process and manufacturing time of the secondary battery by reducing the drawing process according to the additional die and punch.

Next, a battery case 11 manufactured by a method for manufacturing a battery case according to an embodiment of the present invention will be described.

3 is a cross-sectional view of a battery case manufactured by the method for manufacturing a battery case of FIG. 1, and FIG. 4 is an enlarged cross-sectional view of a portion 'A1' of FIG. 3.

3 and 4, the battery case 11 manufactured by the method for manufacturing a battery case according to an embodiment of the present invention has a cylindrical shape, and includes a bottom portion 12 and a sidewall portion 13. It is done by

The bottom part 12 faces the opening formed in the upper part of the battery case 11.

The side wall 13 is connected to the bottom 12 and forms a side wall of the battery case 11. The side wall portion 13 is connected to the first side wall portion 13a having a first thickness T1, the stepped portion 13b connected to the first sidewall portion 13a, and the stepped portion 13b. A second side wall portion 13c having a second thickness T2 that is thicker than one thickness T1 is included. Here, the stepped portion 13b is a portion formed by the thickness difference ΔT between the first sidewall portion 13a and the second sidewall portion 13c.

Looking at the relationship between the first side wall portion 13a and the second side wall portion 13b, the distance between the outer surface of the first side wall portion 13a and the central axis C, and the second side wall portion 13c The distance between the outer surface and the central axis C is equal to each other as R3. However, the distance R1 between the inner surface of the first side wall portion 13a and the central axis C is greater than the distance R4 between the inner surface of the second side wall portion 13c and the central axis C. That is, the second sidewall portion 13c protrudes from the first sidewall portion 13a by a distance difference R3-R4 in the central axis C direction.

Next, a cylindrical secondary battery to which the battery case 11 is applied will be described.

FIG. 5 is a perspective view of a cylindrical secondary battery manufactured using the battery case of FIG. 4, and FIG. 6 is an enlarged cross-sectional view of a portion 'A2' of FIG. 5.

5 and 6, the cylindrical battery 100 to which the battery case 11 is applied includes an electrode assembly 20 disposed inside the battery case 11 and an upper portion of the battery case 11. It includes a cap assembly 30 coupled to the opening, and a gasket 40 installed between the battery case 11 and the cap assembly 30.

Although not shown in detail, the electrode assembly 20 has a positive electrode and a negative electrode, and a separator interposed between the two electrodes is wound in a cylindrical shape to form a jelly roll, and the positive and negative electrode tabs are drawn out from the positive and negative electrodes, respectively. Normally, the positive electrode tab is upward and the negative electrode tab is pulled downward.

Since the battery case 11 has been described in detail above, a detailed description thereof will be omitted. However, the battery case 11 applied to the cylindrical secondary battery 100 further includes a beading part 13e and a crimping part 13f.

The beading part 13e inserts the electrode assembly 20 into the battery case 11 and arranges the upper insulating plate 21 on the electrode assembly 20 during the manufacturing process of the cylindrical secondary battery 100. It is formed by pressing the battery case 11 immediately above the upper insulating plate 21 from the outside to the inside. The beading portion 13e can prevent the up and down flow of the electrode assembly 100.

The crimping portion 13f inserts a gasket 40 between the battery case 11 and the cap assembly 30 during the manufacturing process of the cylindrical secondary battery 100, and the upper portion (ie, the upper portion of the battery case 11). It is formed by bending the end portion of the second side wall portion 13c. The crimping portion 13f has a form surrounding the cap assembly 30 and the gasket 40 to closely contact the battery case 11, the cap assembly 30, and the gasket 40. Since the part of the second sidewall portion 13c having the second thickness T2 thicker than the first thickness T1 is formed by the crimping portion 13f by pressing, the battery case 11 is formed. The bonding strength of the contact area where the cap assembly 30 and the gasket 40 contact may be improved.

The cap assembly 30 includes a safety vent 31, a current blocking means 32, a secondary protective element 33, and a cap up 34.

The safety vent 31 is positioned below the cap assembly 30 in a plate shape, and deforms or ruptures when the pressure rises inside the battery case 11 to damage the current blocking means 32. .

The current blocking means 32 is positioned above the safety vent 310, and breaks when the safety vent 310 is deformed to block current.

The secondary protection element 33 is formed of, for example, a positive temperature element (PTC) and is positioned above the current interruption means 32. The positive temperature element is formed in accordance with an increase in temperature of the secondary battery. As the conductivity decreases, it cuts off the current.

The cap up 34 is positioned on the secondary protection element 33 to cover the upper portion of the secondary battery and serves to provide a positive voltage or a negative voltage to the outside.

As described above, in the cylindrical secondary battery 100 to which the battery case 11 is applied, the upper portion of the battery case 11 (that is, the end of the second sidewall portion 13c) is formed thicker than other portions, and the crimping portion 13f is formed. Even if the end portion of the second side wall portion 13c is bent to form, the bonding strength of the contact region where the battery case 11, the cap assembly 13 and the gasket 40 contact each other in the crimping portion 13f can be improved. Can be.

In addition, in the cylindrical secondary battery 100 to which the battery case 11 is applied as described above, the first sidewall portion 13a is formed to be thinner than the second sidewall portion 13c to form an electrode assembly at the first sidewall portion 13a. The space in which 20 is housed can be secured widely. Accordingly, the cylindrical secondary battery 100 to which the battery case 11 is applied can increase the capacity of the battery.

Next, a method of manufacturing a battery case according to another embodiment of the present invention will be described.

7 is a flowchart illustrating a method of manufacturing a battery case according to another exemplary embodiment of the present invention, and FIGS. 8 and 9 are cross-sectional views for explaining the columnar container deformation step of FIG. 7.

Referring to FIG. 7, the method for manufacturing a battery case according to another embodiment of the present invention includes preparing a case material (S1), forming a columnar container (S2), and transforming a columnar container (S13).

The manufacturing method of the battery case according to another embodiment of the present invention is compared to the manufacturing method of the battery case according to an embodiment of the present invention in the fourth step (7) and the fourth punch (7) in the column container deformation step (S13) The only difference is the addition of carrying out the drawing process using 8) and have the same steps. Accordingly, in the manufacturing method of the battery case according to another embodiment of the present invention, duplicated description will be omitted and will be mainly described for the columnar container deformation step (S13).

Referring to FIGS. 8 and 9, the columnar container deformation step S13 is similar to the columnar container deformation step S3 of the second sidewall portion 13c of the columnar container 11 shown in FIG. 2C. The stepped portion 13b and the second sidewall portion 13c are moved in the direction of the central axis C by using a drawing process so that an inner surface thereof protrudes in the direction of the central axis C rather than the first sidewall portion 13a. It's a push step.

However, the columnar container deformation step S13 may be performed before the drawing process is performed on the columnar container 11 of FIG. 2C using the third die 5 and the third punch 6 of FIG. 2D. And a preliminary drawing process on the columnar container 11 of FIG. 2C using the fourth die 7 and the fourth punch 8. This is because when the stepped portion 13b and the second side wall portion 13c of the columnar container 11 shown in FIG. 2B are pushed in the direction of the central axis C at a time by a drawing process, the columnar container 11 is moved into the columnar container 11. Because of the crowd.

Specifically, the columnar container deformation step S13 is performed between the cup-shaped fourth die 7 and the fourth punch 8 having the second depth D2, as shown in FIG. 8. After arranging the columnar container 11, the fourth punch 8 is moved downward with respect to the fourth die 7. Then, the step portion 13b and the second side wall portion 13c of the columnar container 11 shown in FIG. 2B are partially pushed in the direction of the central axis C. As shown in FIG. Here, an outer angle formed by the first sidewall portion 13a and the stepped portion 13b will be defined as θ2.

The fourth die 7 and the fourth punch used to partially push the stepped portion 13b and the second sidewall portion 13c of the columnar container 11 shown in FIG. 2B in the direction of the central axis C. 8, the fourth die 7 includes a fourth die bottom surface 7a, a fourth die side surface 7b, and a fourth die inclined surface 7c formed therein. The fourth punch 8 includes a fourth punch bottom face 8a, a fourth punch side face 8b and a fourth punch inclined face 8c on the outside.

The fourth die bottom surface 7a bottoms inside the fourth die 7. The fourth die side 7b is connected perpendicularly to the fourth die bottom 7a. The fourth die inclined surface 7c is inclinedly connected to the fourth die side 7b so as to be farther from the center axis C than the distance between the fourth die side 7b and the second die 3 ) Using the fourth die 7 and the fourth punch 8 rather than the outer angle θ1 of the first sidewall portion 13a and the stepped portion 13b formed by the drawing process using the second punch 4. It is inclined so that the outer angle (theta) 2 of the 1st side wall part 13a and the step part 13b formed by the drawing process may become large.

The fourth punch bottom face 8a forms a bottom on the outside of the fourth punch 8 and is parallel to the fourth die bottom face 7a. The fourth punch side face 8b is connected perpendicular to the fourth punch bottom face 8a and is parallel to the fourth die side face 7b. The fourth punch inclined surface 8c is connected to the fourth punch side surface 8b and is parallel to the fourth die inclined surface 7c.

Thereafter, the columnar container forming step S13 moves the fourth punch 8 upward with respect to the fourth die 7 and moves the columnar container 11 shown in FIG. 4 Remove from die (7).

Then, the columnar container deforming step S13 is performed by placing the columnar container 11 of FIG. 8 between the third die 5 and the third punch 6, and then as shown in FIG. 9. 3 The third punch 6 is moved downward with respect to the die 5. Then, the columnar container 11 of FIG. 8 is transformed into the columnar container 11 in which the step portion 13b and the second side wall portion 13c are further pushed into the central axis C. As shown in FIG.

As described above, the columnar container deforming step S13 is performed by preliminarily drawing the columnar container 11 by using the fourth die 7 and the fourth punch 8, thereby completing the bunching of the columnar container 11. In the columnar container 11, the stepped portion 13b and the second sidewall portion 13c may be pushed to protrude in the direction of the central axis C.

In this way, the battery case manufacturing method according to another embodiment of the present invention by preliminarily drawing the columnar container 11 by using the fourth die 7 and the fourth punch 8, Compared to the method for manufacturing a battery case according to an embodiment, the stepped portion 13b and the second sidewall portion 13c are oriented in the central axis C in the columnar container 11 without the burden of the columnar container 11. Can be pushed out to protrude.

Although the present invention has been described with reference to the embodiments illustrated in the accompanying drawings, it is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Could be. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

1 is a flow chart showing a manufacturing method of a battery case according to an embodiment of the present invention.

2A to 2D are cross-sectional views illustrating a method of manufacturing the battery case of FIG. 1.

3 is a cross-sectional view of a battery case manufactured by the method for manufacturing a battery case of FIG. 1.

4 is an enlarged cross-sectional view of a portion 'A1' of FIG. 2.

5 is a perspective view of a cylindrical secondary battery manufactured using the battery case of FIG. 4.

6 is an enlarged cross-sectional view of a portion 'A2' of FIG. 5.

7 is a flowchart illustrating a method of manufacturing a battery case according to another embodiment of the present invention.

8 and 9 are cross-sectional views for explaining the columnar container deformation step of FIG.

* Description of the symbols for the main parts of the drawings *

1, 3, 5, 7: Die 2, 4, 6, 8: Punch

11: battery case 12: bottom

13: side wall portion 13a: first side wall portion

13b: step portion 13c: second side wall portion

Claims (13)

A case material preparation step of preparing the case material; A first sidewall portion having a first thickness and a first sidewall portion which is bent and extended to the bottom portion by carrying out a drawing process such that the case material extends along a central axis, the sidewall portion being bent and extending from the bottom portion; A stepped portion extending obliquely at an end of the first sidewall portion so as to move away from the first sidewall portion by being bent from the stepped portion so as to be parallel to the first sidewall portion and having a second thickness thicker than the first sidewall portion; A columnar container forming step of forming a columnar container to include a second sidewall portion projecting outwardly from the central axis; And And performing a drawing process so that the inner surface of the second sidewall portion protrudes in the central axis direction relative to the first sidewall portion, and deforming the columnar container to push the stepped portion and the second sidewall portion in the central axis direction. , In the forming of the columnar container, the first and second sidewall portions are simultaneously formed in the sidewall portion by using a die having a slanted surface and a punch. The method of claim 1, The columnar container forming step And forming a columnar container having a first height from the case material by performing a drawing process using a cup-shaped first die having a first depth and a first punch. The method of claim 2, The columnar container forming step Performing a drawing process using a cup-shaped second die having a second depth deeper than the first depth and a second punch to form a columnar container having the first height as a columnar container having a second height More, The second die A second die bottom bottomed from the inside; A second die side surface connected perpendicular to the second die bottom surface; A second die inclined surface inclinedly connected to the second die side to be farther from the central axis than the distance between the second die side; And a second connection surface connected to the second die inclined surface so as to be parallel to the second die side surface. The method of claim 3 The second punch is A second punch bottom bottoming outward and parallel to the second die bottom face; A second punch side surface perpendicular to the second punch bottom surface and parallel to the second die side surface; A second punch inclined surface connected to the second punch side and parallel to a second die inclined surface; And  And a second punch connection surface connected to the second punch inclined surface so as to be parallel to the second punch side surface. The method of claim 3, wherein And a vertical distance between the second die side surface and the second die connecting surface is greater than the first thickness. The method of claim 1, In the column container forming step The distance between the inner surface of the first side wall portion and the central axis is shorter than the distance between the inner surface of the second side wall portion and the central axis. The method of claim 3, wherein The columnar container deformation step A drawing process using the third die having a cup shape and the third punch having the second depth is performed, and the distance between the center axis and the outer surface of the first side wall portion and the distance between the center axis and the outer surface of the second side wall portion. To be the same, The third die is A method for manufacturing a battery case comprising: a third bottom surface forming a bottom at an inner side thereof, and a third die side surface connected perpendicularly to the third bottom surface. The method of claim 7, wherein The third punch is A third punch bottom bottoming outward and parallel to the third die bottom; And And a third punch side surface connected perpendicular to the third punch bottom surface and parallel to the third die side surface. The method of claim 1, In the column container deformation step, The distance between the inner surface of the first side wall portion and the central axis is longer than the distance between the inner surface of the second side wall portion and the central axis. The method of claim 7, wherein The columnar container deformation step Before performing a drawing on the columnar container using the third die and the third punch, an auxiliary drawing on the columnar container using the cup-shaped fourth die and the fourth punch having the second depth. Method for manufacturing a battery case comprising the step of performing a step. 11. The method of claim 10, The fourth die is A fourth die bottom bottomed from the inside; A fourth die sidewall connected perpendicularly to the fourth die; And The first side wall portion and the stepped portion which are inclinedly connected to the fourth die side to be farther from the central axis than the distance between the fourth die side, and formed by a drawing process using the second die and the second punch; And a fourth die inclined surface inclined such that the outer sides of the first sidewall portion and the step portion formed by the drawing process using the fourth die and the fourth punch are increased. The method of claim 11, The fourth punch is A fourth punch bottom bottoming outward and parallel to the fourth die bottom face; A fourth punch side surface connected perpendicular to the fourth punch bottom surface and parallel to the fourth die side surface; And And a fourth die inclined surface connected to the fourth punch side surface and parallel to the fourth die inclined surface. A case material preparation step of preparing the case material; A first sidewall portion having a first thickness and a first sidewall portion which is bent and extended to the bottom portion by carrying out a drawing process such that the case material extends along a central axis, the sidewall portion being bent and extending from the bottom portion; A stepped portion extending obliquely at an end of the first sidewall portion so as to move away from the first sidewall portion by being bent from the stepped portion so as to be parallel to the first sidewall portion and having a second thickness thicker than the first sidewall portion; A columnar container forming step of forming a columnar container to include a second sidewall portion projecting outwardly from the central axis; And And performing a drawing process so that the inner surface of the second sidewall portion protrudes in the central axis direction relative to the first sidewall portion, and deforming the columnar container to push the stepped portion and the second sidewall portion in the central axis direction. , The pillar case forming step is a battery case manufactured by a method of manufacturing a battery case for simultaneously forming the first side wall portion and the second side wall portion in the side wall portion using a die and a punch having an inclined surface.

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