Manufacturing device of battery case having improved manufacturing processability and manufacturing method using the same

Abstract

The present invention provides a manufacturing device of a battery case including a first mold including a first space part having a shape corresponding to a storage part formed therein; a second mold including a second space part having a shape corresponding to the storage part and a through-hole communicating with the second space part formed therein, and coupled to the first mold with a laminate sheet interposed therebetween; and an air pressure regulator mounted in the through-hole in a state in which the first space part and the second space part are isolated from the outside, and increasing or decreasing an air pressure of the second space part through the through-hole to stretch and modify the laminate sheet into a shape corresponding to the first space part or the second space part.

Claims

1. An assembly comprising: a laminate sheet composed of an upper layer of a polymer resin, an intermediate layer of a barrier metal, and a lower layer of a polymer resin; and a manufacturing device of a battery case in which a storage part for mounting an electrode assembly for a secondary battery is formed on the laminate sheet, the manufacturing device comprising: a first mold including a first space part having a first shape corresponding to the storage part; a second mold including a second space part having a second shape matching the first shape and corresponding to the storage part, the second mold including a through-hole communicating with the second space part formed therein, and the second mold being coupled to the first mold, wherein a vertical cross-sectional area of the through-hole through which air flows has a size of 0.01% to 5% compared to a total area of the laminate sheet positioned in the second space part before a decrease in air pressure; and an air pressure regulator connected to the through-hole and configured to increase and decrease the air pressure of the second space part through the through-hole to stretch and modify the laminate sheet into a shape corresponding to the first space part and the second space part, respectively.

2. The assembly of claim 1, wherein: the first mold includes first fixing parts that are configured to be in close contact with a lower surface of the laminate sheet along an outer periphery adjacent to a portion for forming the storage part in the laminate sheet; the second mold includes second fixing parts that are configured to be in close contact with an upper surface of the laminate sheet along an outer periphery adjacent to a portion for forming the storage part in the laminate sheet; and the first space part and the second space part are isolated from the outside in a state in which the laminate sheet is fixed between the first fixing parts and the second fixing parts.

3. The assembly of claim 2, wherein: the first space part and the second space part are isolated from the each other by the laminate sheet in a state in which the laminate sheet is fixed between the first fixing parts and the second fixing parts.

4. The assembly of claim 1, wherein: the air pressure regulator sucks air with a pressure of 10×10.sup.5 dyn/cm.sup.2 to 99×10.sup.5 dyn/cm.sup.2 to decrease the pressure.

5. The assembly of claim 1, wherein: the air pressure regulator introduces air with a pressure of 10×10.sup.5 dyn/cm.sup.2 to 99×10.sup.5 dyn/cm.sup.2 to increase the pressure.

6. The assembly of claim 1, wherein: a coating layer for reducing frictional force with the laminate sheet is added to an inner surface of the first and second space parts.

7. The assembly of claim 6, wherein: the coating layer is a resin having a friction coefficient of 0.03 to 0.04.

8. An assembly comprising: a laminate sheet composed of an upper layer of a polymer resin, an intermediate layer of a barrier metal, and a lower layer of a polymer resin; and a manufacturing device of a battery case in which a storage part for mounting an electrode assembly for a secondary battery is formed on the laminate sheet, the manufacturing device comprising: a first mold including a first space part having a first shape corresponding to the storage part formed therein; a second mold including a second space part having a second shape matching the first shape and corresponding to the storage part, the second mold including a through-hole communicating with the second space part formed therein, and the second mold being coupled to the first mold, wherein a vertical cross-sectional area of the through-hole through which air flows has a size of 0.01% to 5% compared to a total area of the laminate sheet positioned in the second space part before a decrease in air pressure; a coating layer for reducing frictional force with the laminate sheet added to an inner surface of the first and second space parts; and an air pressure regulator connected to the through-hole and configured to increase or decrease the air pressure of the second space part through the through-hole to stretch and modify the laminate sheet into a shape corresponding to the first space part or the second space part.

9. The assembly of claim 8, wherein: the coating layer is a resin having a friction coefficient of 0.03 to 0.04.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of a manufacturing device according to an exemplary embodiment of the present invention;

(2) FIGS. 2 and 3 are vertical cross-sectional views of the manufacturing device;

(3) FIG. 4 is a flow chart of a manufacturing method according to an exemplary embodiment of the present invention; and

(4) FIG. 5 is a schematic view showing a manufacturing device according to another exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) Hereinafter, the present invention will be described with reference to the drawings according to Examples of the present invention, which is provided for a better understanding of the present invention, and thus, the scope of the present invention is not limited thereto.

(6) FIG. 1 is a schematic view of a manufacturing device according to an exemplary embodiment of the present invention, and FIGS. 2 and 3 are vertical cross-sectional views of the manufacturing device.

(7) Referring to these drawings, the manufacturing device includes a first mold 110, a second mold 120, and an air pressure regulator 150 connected to the second mold 120.

(8) The first mold 110 includes a first space formed in a shape corresponding to a shape of the storage part 12 in the battery case. The first mold 110 includes first fixing parts 114 that are in close contact with a lower surface of the laminate sheet 10 along an outer periphery adjacent to a portion for forming the storage part 12 in the laminate sheet 10. The laminate sheet 10 is composed of an upper layer 10a of a polymer resin, an intermediate layer 10b of a barrier metal, and a lower layer 10c of a polymer resin.

(9) The second mold 120 includes a second space formed in a shape corresponding to a shape of the storage part 12 in the battery case.

(10) The second mold 120 includes second fixing parts 124 that are in close contact with an upper surface of the laminate sheet 10 along an outer periphery adjacent to a portion for forming the storage part 12 in the laminate sheet 10.

(11) The second mold 120 further includes a through-hole 126 communicating with the second space part 122 and has a structure in which the air pressure regulator 150 is connected to the through-hole 126.

(12) A coating layer 118, 128 having a low friction coefficient is coated on inner surfaces of the first space and the second space so that the frictional force with respect to the laminate sheet 10 is reduced in the first space and the second space in the present invention.

(13) The laminate sheet 10 is disposed between the first mold 110 and the second mold 120, and when the first fixing parts 114 and the second fixing parts 124 are coupled to face each other, and the laminate sheet 10 is fixed between the first mold 110 and the second mold 120 while being in close contact with the first fixing parts 114 and the second fixing parts 124.

(14) Although not shown in the drawings, the coupling between the first mold 110 and the second mold 120 may be achieved by mechanical fastening means, such as a male or female fastening structure or a threaded fastening structure.

(15) When the first mold 110 and the second mold 120 are coupled as described above, the first space part 112 and the second space part 122 are isolated from the outside, and only the second space communicates with the air pressure regulator 150 via the through-hole 126.

(16) In addition, in the state in which the laminate sheet 10 is fixed between the first fixing parts 114 and the second fixing parts 124, the first space part 112 and the second space part 122 are isolated from each other based on the laminate sheet 10.

(17) In this state, the laminate sheet 10 may be modified while being stretched in a direction of the first space part 112 or the second space part 122 according to a change in air pressure in the second space part 122.

(18) In this regard, 3, FIGS. 2 and 3 schematically show a series of processes of forming the storage part 12 in the laminate sheet 10 using the change in air pressure in the second space part 122.

(19) First, referring to FIG. 2A, the air pressure regulator 150 sucks air in the second space part 122 through the through-hole 126 to decrease the air pressure of the second space part 122.

(20) In this state, the air pressure of the second space part 122 is lower than the air pressure of the first space part 112, and the laminate sheet 10 is slowly stretched while moving in the direction of the second space part 122 based on the first space part 112.

(21) When the decrease in pressure is performed for a predetermined time, as shown in FIG. 2B, the laminate sheet 10 is molded in a state of being closely attached to the inner surface of the second space part 122 to form the storage part 12 having the shape of the second space part 122.

(22) In FIG. 2, the second space part 122 has a rectangular structure on a vertical cross section, but may have an amorphous structure including a round shape or a protrusion and depression shape so that the storage part 12 is molded in various forms.

(23) FIG. 3 shows a process of forming the storage part 12 by increasing the air pressure of the second space part 122, on the contrary to FIG. 2.

(24) Referring to FIG. 3A′, the air pressure regulator 150 introduces air into the second space part 122 through the through-hole 126 to increase the air pressure of the second space part 122.

(25) In this state, the air pressure of the second space part 122 is higher than the air pressure of the first space part 112, and the laminate sheet 10 is slowly stretched while moving in the direction of the first space part 112 based on the second space part 122.

(26) When the decrease in pressure is performed for a predetermined time, as shown in FIG. 2B′, the laminate sheet 10 is molded in a state of being closely attached to the inner surface of the first space part 112 to form the storage part 12 having the shape of the first space part 112.

(27) In FIG. 3, the first space part 112 has a rectangular structure on a vertical cross section, but may have an amorphous structure including a round shape or a protrusion and depression shape so that the storage part 12 is molded in various forms.

(28) Further, although not shown separately in the drawing, when the laminate sheet 10 is stretched to the first space part 112, an opening through which air existing in the first space part 112 may be exhausted to the outside may be formed in the first space part 112.

(29) FIG. 4 is a flow chart of a manufacturing method according to an exemplary embodiment of the present invention

(30) Referring to FIG. 4, first, in a process 210, the laminate sheet 10 is disposed between the first mold 110 and the second mold 120, and the first mold 110 and the second mold 120 are coupled in a form in which the first space part 112 formed in the first mold 110 and the second space 122 part formed in the second mold 120 are isolated from each other.

(31) Here, the through-hole 126 communicating with the second space part 122 may be connected to the air pressure regulator 150, and thus the air pressure of the second space part 122 may be changed by the air pressure regulator 150. In the present invention, the air pressure regulator 150 is not particularly limited as long as it is a device capable of modifying the air pressure, and for example, may have a structure in which an air compressor and a vacuum motor are combined.

(32) Thereafter, in a process 220, the pressure of the second space part 122 is changed by the air pressure regulator 150 to induce the stretching of the laminate sheet 10.

(33) Here, the pressure change may be performed by selecting the process of decreasing a pressure by sucking air in the second space part 122 by the air pressure regulator 150, or the process of increasing the pressure by introducing air into second space part 122 by the air pressure regulator 150.

(34) When the method of decreasing in pressure by sucking air in the second space part 122 is selected in the process 220, a primary decrease in pressure with a pressure of about 60×10.sup.5 dyn/cm.sup.2 at an atmospheric pressure, and a secondary decrease in pressure with a pressure of 90×10.sup.5 dyn/cm.sup.2 corresponding to about 150% compared to the pressure of the primary decrease in pressure may be gradationally performed.

(35) In contrast, when the method of increasing in pressure by introducing air into the second space part 122 is selected in the process 220, a primary increase in pressure with a pressure of about 60×10.sup.5 dyn/cm.sup.2 at an atmospheric pressure, and a secondary increase in pressure with a pressure of 90×10.sup.5 dyn/cm.sup.2 corresponding to 150% compared to the pressure of the primary increase in pressure may be gradationally performed.

(36) The gradational change in pressure may gradually induce the stretching of the laminate sheet 10 to increase dimensional accuracy of the storage part 12, and simultaneously, to prevent defects such as cracks and pinholes that may occur when the laminate sheet 10 is stretched in a short time.

(37) Further, the gradational change in pressure may induce relatively uniform stretching of each portion of the laminate sheet 10, for example, a portion that is positioned in the first space and the second space and is directly pressurized by the air pressure, and a portion engaged between the first mold 110 and the second mold 120, and thus the thickness of the storage part 12 may be uniformly formed.

(38) In the process 230, the laminate sheet 10 is stretched in a form corresponding to the first space part 112 or the second space part 122 in response to the pressure change of the second space part 122, and is molded in the storage part 12.

(39) Meanwhile, FIG. 5 is a schematic view showing a manufacturing device according to another exemplary embodiment of the present invention.

(40) The manufacturing device 200 shown in FIG. 5 has a structure similar to that of the manufacturing device shown in FIGS. 1 to 3, and has the same stretching process for the laminate sheet 20 as that of the manufacturing device. However, the manufacturing device is different in that a plurality of through-holes 226 are perforated in the second mold 220.

(41) Specifically, the second mold 220 includes the plurality of through-holes 226 communicating with the second space part (not shown) and has a structure in which an outer surface of the second mold 220 except the through-holes 226 is isolated, and thus the second mold and the air pressure regulator 150 may be coupled to each other, and in some cases, each through-hole 226 may be connected to the air pressure regulator 150.

(42) The vertical cross-sectional area of each through-hole 226 may have a size of about 1% or less compared to a total area of the laminated sheet 20 positioned in the second space part before the decrease in pressure.

(43) This structure allows the suction pressure to be dispersed into the plurality of through-holes without concentrating on any one of the through-holes, thereby preventing the laminate sheet from being stretched through the through-hole or preventing excessive suction pressure from being formed with respect to each of the through-holes, and thus the laminate sheet is capable of being molded in a desired shape.

(44) Hereinafter, the manufacturing device according to the present invention is described in detail with reference to Examples and Comparative Examples.

Example 1

(45) In a state in which a laminate sheet having an area of 400 mm.sup.2 was disposed between the first mold and the second mold, the laminate sheet was molded by decreasing an air pressure in the second mold using an air pressure regulator connected to a through-hole formed in the second mold.

(46) Here, the air pressure regulator decreased the pressure with a pressure of 50×10.sup.5 dyn/cm.sup.2, a vertical cross-sectional area of the through-hole was 19.5 mm.sup.2, a thickness of the laminate sheet was 30 micrometers, and a barrier metal of the laminate sheet was 15 micrometers.

Example 2

(47) A laminate sheet was molded in the same manner as in Example 1 except that the air pressure regulator decreased the pressure with a pressure of 99×10.sup.5 dyn/cm.sup.2.

Example 3

(48) A laminate sheet was molded by using the manufacturing device having the same structure and the same method as in Example 1 except that the vertical cross-sectional area of the through-hole was 3 mm.sup.2.

Comparative Example 1

(49) A laminate sheet was molded in the same manner as in Example 1 except that the air pressure regulator decreased the pressure with a pressure of 9×10.sup.5 dyn/cm.sup.2.

Comparative Example 2

(50) A laminate sheet was molded in the same manner as in Example 1 except that the air pressure regulator decreased the pressure with a pressure of 110×10.sup.5 dyn/cm.sup.2.

Comparative Example 3

(51) A laminate sheet was molded by using the manufacturing device having the same structure and the same method as in Example 1 except that the vertical cross-sectional area of the through-hole was 30 mm.sup.2.

Experimental Example

(52) Depths of storage parts of the laminated sheets molded in Examples 1 to 3 and Comparative Examples 1 to 3 were measured, and results are shown in Table 1 below.

(53) TABLE-US-00001 TABLE 1 Depth of storage part Example 1  9.5 mm Example 2 10.2 mm Example 3 10.7 mm Comparative Example 1  2.7 mm Comparative Example 2 Not measurable Comparative Example 3 Not measurable

(54) As shown in Table 1, when the laminate sheet was molded using the manufacturing device under the conditions according to Examples 1 to 3, the storage part was formed to have a depth at which the electrode assembly was capable of being stored.

(55) On the other hand, in Comparative Example 2, a portion of the laminate sheet was torn and the depth was not measurable. It was thought that the tear of the laminate sheet occurred since the decrease in pressure was performed under relatively high pressure, resulting in excessive stretching of the laminate sheet.

(56) Further, in Comparative Example 3, since the laminate sheet was hardly molded, the depth was not measurable. It was thought that the laminate sheet was hardly molded since sufficient vacuum pressure was not applied to the laminate sheet due to the relatively wide through-hole.

(57) In Comparative Example 1, the depth of the storage part that was actually usable was not formed. Thus, it could be appreciated that the laminate sheet was not stored in a desired form under low pressure as in Comparative Example 1.

(58) It will be understood by those skilled in the art that various modifications and change can be made in the scope of the present invention based on the above description.

INDUSTRIAL APPLICABILITY

(59) As described above, since the manufacturing device and the manufacturing method according to the present invention induces stretching of the laminate sheet in accordance with increase or decrease in air pressure, the frictional force applied to the laminate sheet during the stretching process may be remarkably low as compared to a structure in which the laminate sheet is pressed in a direct contact state, for example, a deep drawing method using a punch, thereby preventing defects such as cracks and pinholes and stretching the laminate sheet in the form of a storage part having a deeper depth.