KR20210106095A - Secondary battery case manufacturing method having a improved edge and the secondary battery case manufactured thereby - Google Patents

Abstract

The present invention relates to a manufacturing method for a secondary battery case with a bent edge, which prevents a cut line from being mismatched or a bonded edge from protruding outward by rounding corners formed by bonding a cut plate-shaped raw material without the need for a separate rounding structure, and a secondary battery case manufactured thereby. The loss of raw materials can be minimized, and the edges of the case can be naturally bent during bonding by cutting appropriately the same to the bent shape, and problems that occur when cutting and bonding plate-shaped raw materials can be solved.

Description

A secondary battery case manufacturing method having improved edges and a secondary battery case manufactured thereby

The present invention cuts the plate-shaped raw material constituting the battery case, and the corners generated by joining the cut plate-shaped raw material without the need to include a separate rounding structure are rounded together with the joint, so that the incision line is mismatched or joined. The present invention relates to a method for manufacturing a case for a secondary battery having a bent corner that prevents the corner from protruding outward, and a case for a secondary battery manufactured thereby.

Through this, the loss of raw materials can be minimized, and the edges of the case are naturally bent during bonding by cutting appropriately for the bent shape, and problems that occur when cutting and joining plate-shaped raw materials can be solved.

A secondary cell battery refers to a battery that can be used semi-permanently by charging electricity generated in the process of causing oxidation and reduction reactions of materials between an anode and a cathode by an electric current supplied from an external power source. These secondary batteries have the advantage that they can be recharged multiple times, and are expected to expand further along with the growth of the electric vehicle market in the future as a core material for electric vehicles as well as portable electronic devices.

A secondary battery case for protecting the secondary battery may be divided into a pouch-type case and a can-type case.

The double can case has advantages in that it is more durable than the pouch-type battery case and can be mass-produced, and the process steps are smaller than that of the pouch-type battery case during mass production, so the cost reduction is relatively large.

On the other hand, in order to produce such a can-type battery case, it is produced using the deep drawing method. Therefore, there is a problem that the manufacturing cost is high.

In addition, the "impact molding apparatus for manufacturing a battery case" described in Korean Patent No. 10-1430711 is described, but since the case is manufactured through a single pressing operation, precision is required in the pressing operation of the punch. There is also the inconvenience that it is difficult to solve the problem or that a separate technology development is required to increase the precision even if it is solved.

In order to solve the problems of the prior art, it is possible to have a case for a secondary battery by cutting and welding an aluminum plate constituting the case.

That is, as shown in FIG. 8 , after cutting in a “Y” shape that can minimize material loss, the battery case in the shape of a square can can be produced by joining them.

However, a problem arises that the incision line does not form a straight line at the part where the "Y"-shaped incision method meets, and the edge protrudes.

Specifically, as the edge portions forming the case are joined, the edge thickness is increased and sharply protrudes outward, which may cause inconvenience in installation.

In this case, a small gap or crack occurs at the edge of the case, and a separate process is required to solve it. There is a hassle that a separate process for cutting it is required.

Republic of Korea Patent Publication No. 10-1430711 (2014.08.14. Announcement) Republic of Korea Patent Publication No. 10-1600929 (2016.03.21.Announcement) Republic of Korea Patent Publication No. 10-0879895 (2009.01.21.Announcement)

The present invention has been devised to solve the above problems, and the edge produced by cutting the plate-shaped raw material constituting the battery case and joining the cut plate-shaped raw material without the need to include a separate rounding structure is junction and It is an object of the present invention to provide a secondary battery case manufacturing method and a secondary battery case manufactured by the rounding process having an improved edge that prevents the inconsistency of incision lines or the protrusion of the joined edges to the outside.

In addition, it is possible to minimize the loss of raw materials, cut the raw materials to suit the bending shape so that the edges of the case are naturally bent when joining, and improved corners that can solve the problems that occur when the plate-shaped raw materials are cut and joined after cutting It is an object of the present invention to provide a secondary battery case manufacturing method having a, and a secondary battery case manufactured thereby.

In addition, since it can be completed by joining the cut raw materials or by single pressing the joined case, the manufacturing process is simple, rapid production is possible, and a method for manufacturing a case for secondary batteries having improved edges that has a cost reduction effect; It is an object of the present invention to provide a case for a secondary battery manufactured thereby.

As a means for achieving the object of the present invention, the side surface is folded in a Y-shape by cutting the raw material in the shape of a plate, and the upper surface produced by joining the side surfaces by laser welding is a secondary having an improved edge in the hexagonal shape. In the battery case manufacturing method,

A raw material cutting step of cutting the raw material to form a joint surface and a cross-section, and bending the cut raw material to vertically bend the cross-section formed on both sides around the scene at the bottom, and perpendicular to the cross-section around the scene A bending step in which the lower end of the joint surface and the upper end of the cross-section are in close contact by bending the opposite ends to be vertically upward to form a side surface, and vertically bending the joint surface formed at both ends around the side surface to the side where the cross-section is located And, a bonding step of bonding through welding so that the bent bonding surface lower end and the cross-sectional upper end are in close contact and fixed in a hexahedral shape, and pressing the raw material having a hexahedral shape by pressing the scene in close contact with the mold. includes steps.

In addition, in the raw material cutting step, a cut surface is formed by cutting in a vertical direction toward the center of the raw material, and the cut surface is separated from the raw material to form the bonding surface and the cross section.

At this time, the incision surface is formed with an inclined incision line that gradually narrows in width as it goes toward the center of the raw material from both sides around the vertically depressed part, and at the end of the inclined incision line, the scene and the cross section are in contact. A horizontal incision is formed horizontally with the

In addition, both sides of the inclined incision line have the same inclination so that the cross section has an isosceles triangular shape, and the upper end of the cross section formed by cutting the inclined incision line and the lower end of the bonding surface precisely abut against each other in the bending step.

In addition, in the bending step, a portion in which the side surface and the bonding surface contact is bent to form a vertical edge, and the scene and the side contact portion are bent to form a scene edge, and the scene and the cross-section contact portion are bent to form a cross-sectional edge, and the vertical edge, the scene edge and the cross-sectional edge are bent and abutted to form a curved edge.

In addition, the mold is composed of a pad having a shape corresponding to the flat surface of the scene and a die installed in four directions around the pad, and the inside of the die is recessed into a shape corresponding to the curved edge of the scene. When the secondary battery case is introduced into the mold, a gap is not generated with the mold.

In addition, it is possible to provide a case for a secondary battery having an improved edge manufactured through the above-described method for manufacturing a case for a secondary battery.

The method for manufacturing a case for a secondary battery having a bent edge according to the present invention and the case for a secondary battery manufactured thereby cut the plate-shaped raw material constituting the battery case, and the cut-out plate-shaped raw material without including a separate rounding structure It has a remarkable effect that it can prevent the inconsistency of the incision line or the protrusion of the joined edge to the outside by rounding the edges together with the joint.

In addition, the present invention can minimize the loss of the raw material, cut the raw material to suit the bending shape so that the edge of the case is naturally bent during bonding, and the bending that can solve the problems that occur when the plate-shaped raw material is cut and then joined It has the remarkable effect of being able to have a curved edge.

In addition, since it can be completed by joining the cut raw materials or by single pressing the joined case, the manufacturing process is simple, rapid production is possible, and the production cost can be reduced.

1 shows the appearance of a case for a secondary battery having an improved edge according to the present invention.
2 is a flowchart illustrating a method for manufacturing a case for a secondary battery having an improved edge according to the present invention.
3 to 6 show a sequence of a method for manufacturing a case for a secondary battery having an improved edge according to the present invention.
7 is a view showing the conventional step of pressing the case for a secondary battery and the step of pressing the case for a secondary battery according to the present invention.
8 shows a related art in the prior art.

Hereinafter, it will be described in detail with accompanying drawings so that those skilled in the art can easily implement the present invention, a method for manufacturing a case for a secondary battery having a bent edge and a case for a secondary battery manufactured by the method.

1 shows the appearance of a case for a secondary battery having improved corners according to the present invention, FIG. 2 is a flowchart of a method for manufacturing a case for a secondary battery having an improved corner according to the present invention, and FIGS. 3 to 6 are Shows the sequence of a method for manufacturing a case for a secondary battery having an improved edge according to the present invention, and FIG. 7 shows the conventional step of pressing the case for a secondary battery and the pressing step of the case for a secondary battery according to the present invention.

The plate-shaped raw material constituting the secondary battery case 100 according to the present invention is cut, and the edge produced by joining the cut plate-shaped raw material without the need to include a separate rounding structure is rounded with the joint. The present invention relates to a method for manufacturing a case for a secondary battery having bent corners in which incision lines are mismatched or joined edges are prevented from protruding outward, and a case for secondary batteries manufactured thereby.

The case 100 for a secondary battery according to the present invention is manufactured through a raw material cutting step (S10), a bending step (S20), a bonding step (S30) and a pressing step (S40).

Prior to the description, the vertical edge 120, the scene edge 130, and the cross-sectional edge 140 that are bent in the raw material 100a are indicated with lines, but this is to easily indicate the position where they are formed, and the bending step (S20) It is revealed in advance that it is an accurate manufacturing method to have a fine width so that it can be bent and bent easily.

1) Raw material cutting step (S10)

The raw material 100a having a plate shape as shown in FIG. 3 has a rectangular shape, and the side having a relatively short length is positioned to face the lateral direction, and then the cut surface 100b is formed by the cut line 110 in the center of the side end. Cut and separate.

On the other hand, it is revealed in advance that the cut line 110 has been processed so as to be separated from the shape of the raw material 100a by displaying it with a thick line. In addition, the cut-off line 110 is cut in the same shape in the up-and-down direction around the center of the side, but it is not cut in a simple straight line, so it will be described with reference to FIG. 3A, which is an enlarged portion of part A of FIG. 3 .

First, the cut-off line 110 is vertically recessed toward the center side of the side end of the raw material 100a equal to the horizontal length of the bonding surface 104 of the secondary battery case 100, and may have a triangular cross-section 102. As the both ends are recessed inward, the incised width has a slope that becomes narrower.

At this time, the degree of being vertically depressed toward the center of the side end of the raw material 100a should be depressed to correspond to the upper end of the inclined one side of the cross section 102 .

Accordingly, the cross section 102 in the shape of an isosceles triangle is formed by the inclined incision lines 110a on both sides that are narrowed because the upper and lower ends are cut in parallel.

In the portion where the inclined incision line 110a is in contact with each other, the horizontal incision line 110 is formed with the scene 101 and the section ( 102) is formed horizontally with the abutting part. Therefore, the horizontal width of the horizontal incision line 110 formed in the portion where the inclined incision line 110a abuts corresponds to the portion where the scene edge 130 is bent, and the raw material 100a is not formed in the bending step (S20). ) in which the inclined incision line 110a is folded to prevent the raw material 100a from being agglomerated.

At this time, the inclined cut line 110a has the same inclination and is cut so that the inclined cut line 110a and the upper both sides of the end face 102 have the same length in the bending step (S20) so that they can abut seamlessly.

In addition, since the inclined cut line 110a and the horizontal cut line 110 are formed to be spaced apart corresponding to the scene edge 130 and the cross section edge 140, respectively, when bending in the bending step (S20), the vertex of the scene 101 Also, they are bent together to have a bending angle 101a. Through this, all lower vertices of the secondary battery case 100 are manufactured in a bent state to have an improved corner shape.

Since the cross-section 102 is also vertically folded in the bending step S20, it may be formed spaced apart by the cross-sectional edge 140 from the position where the scene 101 is to be formed. That is, the part in contact with the scene 101 having the maximum width in the horizontal incision line 110 and the cross section 102 is folded in the bending step (S20) by forming the section edge 140, so that of the length of the scene 101 It is formed to be spaced apart as much as it corresponds to the short part and the cross-sectional edge 140 .

In this way, the cut surface 100b cut along the cut line 110 is separated from the raw material 100a in the raw material cutting step S10 and discarded, and as described above, in order to manufacture the case 100 for secondary batteries, the minimum The effect of cost reduction can also be obtained by discarding only a part.

2) Banding step

In the bending step (S20), the raw material (100a) cut in the raw material cutting step (S10) is respectively formed by bending along the vertical edge 120, the scene edge 130 and the sectional edge 140, and the vertical edge 120 , the part where the scene edge 130 and the cross-sectional edge 140 abut is a step in which the bending edge 150 is formed by bending.

First, as shown in FIG. 4 , the end of the portion cut in the direction perpendicular to the center of the raw material 100a by the cut-off line 110 (shown by the dashed-dotted line) is the vertical edge 120 of the secondary battery case 100 is formed. As a part to be, it is bent along the distal end so that the bonding surface 104 is formed on both sides.

Thereafter, as shown in FIG. 5 , the long side is bent around the part where the scene 101 is to be formed so that the scene edge 130 is formed along the part where the side surface 103 is to be formed, and the scene 101 is centered on the The cut-out portion where the cross-section 102 is to be formed is bent to form a cross-sectional edge 140 .

Therefore, when the scene edge 130 and the cross-sectional edge 140 of FIG. 5 are bent, they have a case shape as in FIG. The lower end of the 104 and the upper end of the cross-section 102 abut and are joined to have an inverted "Y" shape.

In addition, the vertical edge 120, the scene edge 130, and the sectional edge 140 are bent, respectively, to form a curved edge 150, wherein the scene edge 130 and the sectional edge 140 are respectively as shown in FIG. 3 Since it is cut apart by a portion corresponding to the edge of the , it is possible to prevent aggregation of the raw material 100a by minimizing the portion joined to each other during bending. In addition, by cutting so as to be spaced apart from the corresponding portions, it is possible to prevent the occurrence of gaps due to excessive incision, thereby preventing the occurrence of holes on the curved edge 150 side.

3) bonding step

As shown in FIG. 6 , the raw material 100a after the bending step S20 has the shape of a case 100 for a secondary battery, and the portion where the pair of bonding surfaces 104 are in contact and the end face 102 and the bonding surface 104 are in contact. The case 100 for a secondary battery is manufactured by bonding the edge portion of the “Y” shape through welding.

In this case, it is most preferable to use laser welding or the like for welding, but the present invention is not limited thereto.

4) Compression step

On the other hand, the case 100 for a secondary battery joined through welding in the bonding step (S30) can be manufactured, but may occur in the finishing process and the raw material cutting step (S10), the bending step (S20) and the bonding step (S30) The raw material 100a may protrude outside the shape of the secondary battery case 100 due to an error.

Therefore, in the present invention, the secondary battery case 100, which has completed the bonding step (S30), is compressed through the mold 200 so that the corner constituting the secondary battery case 100 can be bent.

In the conventional compression process, dies 210 spaced apart from each other are provided on both sides as shown in FIG. , in this case, since the inner cross section of the mold 200 is formed in a rectangular shape, a gap is generated between the mold 200 and the secondary battery case 100 .

Therefore, in the case of the case 100 for a secondary battery having a curved edge, it is very difficult to compress the edge, and rather, if excessive pressing pressure is applied during the compression process, the secondary battery case 100 is pushed toward the pad 220 and the curved edge is There is also the risk of sharp formation.

In the present invention in order to solve the above problems, the pad 220 is a flat part in the scene in close contact with the pad 220, that is, the scene edge 130 and the sectional edge 140 in contact with the scene 101. Scene ( 101) to be formed in a shape corresponding to the portion, the die 210 is installed in each of four directions centering on the pad 220, and the inner surface of the die 210 has a vertical edge 120 and a scene edge 130. , the cross-sectional edge 140 and the curved edge 150 have a shape that is recessed inward to accommodate the curved edge 150 as shown in FIG. can be

Therefore, it is possible to solve the problem of the bent corner 150 that may occur (agglomeration of materials, sharp corners, etc.), and it is possible to manufacture the case 100 for the secondary battery having the bent corner desired by the manufacturer.

The case 100 for secondary batteries manufactured through the raw material cutting step (S10), the bending step (S20), the bonding step (S30) and the pressing step (S40) described above is a work for creating a separate curved edge through a minimum incision Curved edges can be formed only by bending without bending, and when cutting, the distance corresponding to each edge is precisely calculated, and then curved and curved edges are formed at the same time as bending by cutting and bending. It is possible to prevent material aggregation and the like.

The case 100 for secondary batteries manufactured by the above-described method has an open top surface as shown in FIG. 1 , has a hexahedral shape with a hollow inside, and can accommodate a secondary battery therein.

Therefore, unlike the method of forming a hollow inside the case through the conventional deep drawing method, etc., it is possible to solve the problem of an increase in production cost caused by the deep drawing method by manufacturing so that the hollow is formed through bending and welding.

On the other hand, FIG. 6a is a partially enlarged side sectional view showing a portion in which a curved edge 150 is formed while the scene edge 130 and the cross-sectional edge 140 are bent in the bonding step.

As such, in the bending step, the outside of the bending edge 150 is bent to have an outside bending angle 101a. The outside bending angle 101a is the scene edge 130 and the cross-sectional edge 140 according to the thickness of the raw material 100a. ) and the outward bending angle 101a are different.

In the present invention, it is optimal to prevent cracks in the protruding shape or curved edges due to aggregation of the raw material 100a during bending, and to prevent leakage of the battery to be included because a gap is generated when each component is excessively spaced apart. By deriving the manufacturing cost of the experimentally and applying it during manufacturing, the case 100 for a secondary battery is effectively manufactured.

The experiment and production costs for this are as follows.

First, the thickness T of the raw material 100a is arbitrarily set to 0.6 mm, and the width of the cross-sectional edge 140 is obtained based on the thickness T of the raw material 100a.

At this time, in the case of the cross-sectional edge 140, if it is formed larger than the thickness of the raw material 100a, there is a risk that the cross-section 102 and the bonding surface 104 do not come into contact, so the width of the cross-sectional edge 140 is the raw material 100a ), the experiment was carried out within a range less than the thickness of the comparison group, and the banding step was performed by manufacturing 9 comparison groups in 10% increments centered on the thickness (T) of the raw material 100a, respectively, and the scene edge 130. The width of the cross-sectional edge 140 was set to twice the width. This is shown in Table 1 below.

Comparative group 1 Comparative group 2 Comparative group 3 Comparative group 4 Comparative group 5 Comparative group 6 Comparative group 7 Comparative group 8 Comparative group 9 width
(mm) 0.06 0.12 0.18 0.24 0.3 0.36 0.42 0.48 0.54 with raw materials
thickness ratio
10%
20%
30%
40%
50%
60%
70%
80%
90%
note
micro-cracks
micro-cracks
more
does not exist
micro-cracks
micro-cracks
micro-cracks
crack
generation
crack
generation
large cracks

As shown in Table 1 above, when the thickness ratio with the raw material 100a was 10 to 20% and 40 to 60%, the end face 102 and the bonding surface 104 were not sufficiently joined, resulting in microcracks. When it is 90%, a problem such as a large amount of cracks occurring in the bent edge 150 has occurred.

Through this, it was possible to derive through an experiment that the width of the cross-sectional edge 140 is most preferably corresponding to 30% of the thickness of the raw material 100a.

On the other hand, the cross-sectional edge 140 is cut in a drawing method to form a predetermined width.

In addition, when the width of the section edge 140 is manufactured in a ratio of 0.3:1 to the thickness of the raw material 100a, an experiment was conducted as shown in Table 2 below to determine the optimal width of the scene edge 130 .

In the case of the width of the scene edge 130, since the inclined incision line 110a formed in the cross section 102 and the bonding surface 104 is folded in the bonding step as shown in FIG. 6, the bending edge 150 formed through the folding step. It will affect the lateral angle. That is, when the width of the scene edge 130 is narrow while bonding, the cross-section 102 and the bonding surface 104 abut excessively, resulting in material aggregation, and when the scene edge 130 is wide, the cross-section 102 And the bonding surface 104 is not sufficiently bonded to generate a gap, there is a risk that the battery leakage (leak) occurs.

Therefore, the above-mentioned problem does not occur, and in order to obtain the curved edge 150 that does not protrude outward, it must be manufactured with the optimal width of the scene edge 130 .

The width of the scene edge 130 is divided by the width ratio between the scene edge 130 and the section edge 140 based on the width of the section edge 140 from 1:1 to 1:2.5, and the difference between the comparison groups is each Comparative groups a ~ were produced by giving 2.5 each, and the state of the bending edge 150 during the bonding step is shown in Table 2 below.

control group a control group b control group c control group d control group e control group f control group g width ratio 1:1 1:1.25 1:1.5 1:1.75 1:2 1:2.25 1:2.5 note Large amount of material agglomeration material agglomeration Material agglomeration micro-occurrence Material agglomeration micro-occurrence more
does not exist small gaps
crevice

As shown in Table 2, in the case of comparative groups a to d, material aggregation occurred on the curved edge 150 side, and in particular, in the case of comparative group a, the material aggregation occurred excessively and protruded outward.

In addition, in the case of the comparative groups f and g, it is not sufficiently joined, a fine gap is generated on the bent edge side, and a leak problem occurs.

Therefore, the width ratio of the scene edge 130 and the section edge 140 is 1:2, that is, it is most preferable that the width of the scene edge 130 is made twice as large as the width of the section edge 140, and the above-mentioned It was confirmed that no problems occurred.

On the other hand, when the width ratio between the scene edge 130 and the cross-sectional edge 140 goes down to 1:1 or less, it can be determined that material aggregation can occur even with the naked eye, and when it exceeds 1:2.5, the bonding surface 104 ) and the cross-section 102 were excessively spaced apart, so it was easily determined that they would not be sufficiently joined, so the width ratio of the comparative group was limited to 1:1 to 1:2.5.

Therefore, the width of the scene edge 130 and the cross-sectional edge 140 according to the thickness of the above-described raw material 100a, and the outer bending angle 101a are manufactured by limiting the corner of the secondary battery case 100 is curved shape It is possible to solve problems that may occur due to the existing angled edges and at the same time prevent aggregation, cracks, and gaps between the raw materials 100a during the bending step, so that a more complete case 100 for secondary batteries can be obtained. have the advantage of being

In addition, according to the thickness of the raw material 100a, the width of the scene edge 130 and the cross-sectional edge 140 and the curvature of the outer bending angle 101a change, so that it can be effectively manufactured according to the various materials and thickness of the raw material 100a. have.

A scene 101 is formed on the lower surface corresponding to the open upper surface, and a scene edge 130 is formed on the part in contact with the side surface 103 on the long edge side with respect to each scene 101, and the length is relatively long. A cross-sectional edge 140 is formed at a portion in contact with the cross-section 102 on the short edge side.

The scene edge 130 and the cross-sectional edge 140 have a curved shape while being bent inward along with bending.

First, the side 103 connected to the scene 101 around the scene edge 130 is vertically bent around the upper side of the scene 101, and both sides of the side 103 are formed during the raw material cutting step (S10). A bonding surface 104 is provided, respectively.

The bonding surface 104 and the side surface 103 are bent in a form in which the bonding surface 104 is perpendicular to the side surface 103 around the vertical edge 120, and thus has a curved shape.

The four bonding surfaces 104 respectively provided on the pair of side surfaces 103 are vertically bent in the direction in which the end surface 102 is positioned in a form orthogonal to the side surface 103 to each other.

In addition, the cross-section 102 connected to the scene 101 around the cross-sectional edge 140 has a triangular shape that becomes narrower as it is spaced apart from the scene 101 in the raw material cutting step (S10), such a cross-section 102 is bent upwards around the cross-sectional edge 140 .

Accordingly, the upper end of the cross section 102 vertically bent upward is in contact with the lower surface of the bonding surface 104 provided on both sides, respectively, and is abutted in an inverted "Y" shape.

At this time, the vertical edge 120, the scene edge 130, and the section edge 140 are bent in three directions as the bent corner 150 is formed to have a shape bent in three directions. Case 100 for secondary batteries ) of the scene 101 is formed by bending all vertices.

Therefore, in the process of folding the raw material 100a without a separate bending process, the corner has a bent shape, and through this, the problems such as hole generation or material aggregation, which are problems with the vertices of the conventional hexahedral secondary battery case. can be solved, and it is possible to prevent the external configuration from being caught in or damaged by the case 100 for secondary batteries because the edges are not sharp.

On the other hand, what has been described using FIGS. 1 to 7 above describes only the main points of the present invention, and as many designs are possible within the technical scope, the present invention is not limited to the configuration of FIGS. 1 to 7 is self-evident

100: secondary battery case 100a: raw material
100b: cut plane 101: scene
101a: lateral bending angle 102: cross section
103: side 104: joint surface
110: incision line 120: vertical edge
130: scene edge 140: section edge
150: curved edge 200: mold
210: die 220: pad

Claims (8)

In the method for manufacturing a case for a secondary battery of a hexagonal shape with an open upper surface produced by cutting a plate-shaped raw material, the side is folded in a Y-shape, and the side is joined by laser welding,
a raw material cutting step of cutting the raw material to form a joint surface and a cross section;
By bending the cut raw material, the cross-section formed on both sides of the scene at the bottom is vertically bent, and both ends perpendicular to the cross-section are bent vertically upwards around the scene to form a side surface, and the a bending step in which a lower end of the joint surface and an upper end of the cross-section are in close contact by vertically bending the joint surface formed at both ends around the side surface to the side where the cross-section is located;
a joining step of joining through welding so that the bent lower end of the joint surface and the upper end of the cross-section are in close contact and fixed in a hexahedral shape; and
A method of manufacturing a case for a secondary battery having an improved edge, comprising: a pressing step of pressing the joined raw material having a hexahedral shape by pressing the scene to be in close contact with the mold.
According to claim 1,
In the raw material cutting step, a cut surface is formed by cutting in a vertical direction toward the center of the raw material, and the cut surface is separated from the raw material to form the joint surface and the cross-section. A method for manufacturing a battery case.
3. The method of claim 2,
The incision surface has an inclined incision line whose width gradually narrows toward the center of the raw material from both sides around the vertically depressed portion;
A method for manufacturing a case for a secondary battery having improved corners, characterized in that at the end of the inclined incision line, a horizontal incision line formed horizontally with a portion where the scene and the cross section meet is formed.
3. The method of claim 2,
The inclined incision line has the same slope on both sides so that the cross section has an isosceles triangle shape,
The method for manufacturing a case for a secondary battery having an improved edge, characterized in that the upper end of the cross section formed by cutting the inclined incision line and the lower end of the bonding surface precisely contact each other in the bending step.
According to claim 1,
The banding step
A portion in contact with the side surface and the joint surface is bent to form a vertical edge,
A portion where the scene and the side are in contact is bent to form a scene edge,
A portion where the scene and the cross-section are in contact is bent to form a cross-sectional edge,
A method for manufacturing a case for a secondary battery having an improved edge, characterized in that the vertical edge, the scene edge, and the section edge are bent and abutted to form a curved edge.
6. The method of claim 5,
The ratio between the width of the cross-sectional edge and the thickness (T) of the raw material is 0.3:1,
A method for manufacturing a case for a secondary battery having an improved edge, characterized in that the width of the scene edge is manufactured to be twice the width of the cross-sectional edge.
According to claim 1,
The mold is composed of a pad having a shape corresponding to the flat surface of the scene; and a die installed in four directions around the pad;
The inner side of the die is recessed into a shape corresponding to the curved edge of the scene, so that when the secondary battery case is drawn into the mold, a gap with the mold is not generated. Way.
A case for a secondary battery having an improved edge manufactured by the method for manufacturing a case for a secondary battery according to claim 1 .

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