Specification
Title of Invention: Method for manufacturing a pouch-type battery case having a venting induction part and a pouch-type battery case manufactured by the method
technical field
[One]
This application claims the benefit of priority based on Korean Patent Application No. 2019-0140964 on November 6, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[2]
The present invention relates to a method for manufacturing a pouch-type battery case in which a venting induction part is formed and a pouch-type battery case manufactured by the method, specifically, a venting induction part in a part of the pouch-type battery case during the manufacturing process of the pouch-type battery case. It relates to a pouch-type battery case manufacturing method including a molding process and a pouch-type battery case manufactured thereby.
background
[3]
Lithium secondary batteries can be broadly classified into cylindrical secondary batteries, prismatic secondary batteries, and pouch-type secondary batteries according to their appearance. can be
[4]
According to the trend toward miniaturization and weight reduction of wearable devices and mobile devices, the demand for thin prismatic batteries and pouch-type batteries is increasing, and in particular, cylindrical or prismatic secondary batteries using metal cans. Since the weight of the battery case can be significantly reduced, the battery can be reduced in weight, and there is a high interest in pouch-type secondary batteries that can be modified in various shapes. The pouch-type secondary battery is a type in which an electrode assembly is embedded in a battery case made of a laminate sheet including a resin layer and a metal layer in a pouch-type shape.
[5]
In the lithium secondary battery, the temperature of the electrode assembly and the electrical connection member increases due to the heat generated during the continuous charging and discharging process. As described above, when the temperature inside the lithium secondary battery increases, the electrolyte is decomposed and gas is generated to expand the battery case. In addition, since the mid-to-large battery pack has a structure in which a plurality of battery cells are mounted in a fixed state in a certain case, each of the expanded battery cells is further pressurized in the limited case, and the risk of ignition and explosion under abnormal operating conditions is reduced. increases
[6]
Various attempts are being made to reduce the risk of such a lithium secondary battery. Patent Document 1 is coated along the direction in which the case is contracted due to an increase in the internal pressure of the battery so that it is preferentially broken over other parts to discharge the gas to the outside. A lithium polymer battery including a breakable layer formed on the outer surface of a case, wherein the breakable layer is a polymer material coated on the outer surface of the case with a predetermined width, and is a material having excellent elongation.
[7]
Patent Document 2 discloses that physical deformation is induced when a predetermined pressure is applied on a sealing portion of a portion corresponding to an electrode lead having relatively low flexibility among a pair of electrode leads connected to the electrode assembly, thereby causing internal gas. Disclosed is a battery cell in which a weak part is formed.
[8]
However, Patent Document 1 and Patent Document 2 do not suggest a specific method for forming a fracture layer or a weak part.
[9]
On the other hand, Patent Document 3 discloses a method of manufacturing a pouch-type secondary battery comprising the step of installing an inner blocking line and an outer blocking line along the edge of the electrode assembly adjacent to the electrode assembly in the gas pocket portion. However, the inner and outer blocking lines are only a structure to prevent the electrolyte from being discharged together during the degassing process during manufacture of the pouch-type secondary battery, and have not disclosed a technology for securing the safety of the pouch-type secondary battery.
[10]
As such, in the manufacturing process of the pouch-type secondary battery, it is necessary to develop a method for preventing the battery case from explosion by inducing breakage on the outer surface of the pouch-type battery case.
[11]
(Prior art literature)
[12]
(Patent Document 1) Korean Patent Application Laid-Open No. 2003-0035187 (2003.05.09)
[13]
(Patent Document 2) Korean Patent Publication No. 2008-0094602 (October 23, 2008)
[14]
(Patent Document 3) Korean Patent Publication No. 2018-0059373 (2018.06.04)
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[15]
The present invention is intended to solve the above problems, and when the venting induction part is formed during the process of forming the pouch-type battery case, the pouch-type battery case manufacturing process can be simplified, and the pouch-type battery case breaks when the internal pressure increases. An object of the present invention is to provide a method for manufacturing a pouch-type battery case including a structure capable of preventing explosion by being induced, and a pouch-type battery case manufactured by the method.
means of solving the problem
[16]
The method for manufacturing a pouch-type battery case according to the present invention for achieving this object includes the steps of (a) positioning a laminate sheet for a pouch-type battery case on a lower molding frame, (b) pressing the laminate sheet with an upper molding frame to obtain an electrode Forming an assembly receiving part, (c) forming a venting induction part on the bottom of the electrode assembly receiving part, and (d) forming a pouch-type battery case in which the electrode assembly receiving part and the venting inducing part are molded into the lower molding mold It may include the step of removing from.
[17]
In one embodiment, the steps (b) and (c) are performed simultaneously, and the upper molding frame has a size corresponding to that of the bottom of the electrode assembly receiving part, and a groove is formed on the lower surface. The first upper molding frame may be a first lower molding frame in which a protrusion is formed on an upper surface corresponding to the groove of the first upper molding die.
[18]
In another embodiment, the steps (b) and (c) are sequentially performed, and in the step (b), the size of the lower surface is the second upper molding having a size corresponding to the bottom of the electrode assembly receiving part. Using a mold and a second lower molding die, the step (c) is, the size of the lower surface is made of a size corresponding to the bottom of the electrode assembly receiving portion, the first upper molding frame is formed with a groove on the lower surface, and, A first lower molding die having a protrusion formed on an upper surface corresponding to the groove of the first upper molding die may be used.
[19]
The groove may be formed in the center of the first upper mold.
[20]
In addition, as a structure in which the protrusion is inserted into the groove, the groove and the protrusion have sizes and shapes corresponding to each other, and the shape of the protrusion may be any one of a polygonal pyramid, a polygonal truncated pyramid, a cone, a truncated cone, and a hemisphere.
[21]
The protrusion may be formed such that a plurality of protrusions are concentrated in the center of the lower molding frame.
[22]
Step (c) may be performed a plurality of times in order to reduce the thickness of the metal layer of the venting inducing part.
[23]
In addition, the step (c) may include punching the laminate sheet a plurality of times.
[24]
The pouch-type battery case according to the present invention includes an upper case and a lower case including an outer coating layer, a metal layer and an inner adhesive layer, and at least one of the upper case and the lower case has an electrode assembly receiving part formed therein, The electrode assembly accommodating part may have a structure in which a vent induction part is formed.
[25]
A thickness of the metal layer in the venting inducing part may be thinner than a thickness of a bottom of the electrode assembly accommodating part except for the venting inducing part.
[26]
The venting inducing part may be formed in a central portion of the bottom of the electrode assembly accommodating part.
[27]
The venting pressure of the venting induction part is smaller than the venting pressure of the upper case and the lower case sealing part which are heat-sealed.
[28]
The present invention also provides a pouch-type battery cell including the pouch-type battery case.
Brief description of the drawing
[29]
1 is a schematic diagram of a method for manufacturing a pouch-type battery case according to a first embodiment.
[30]
2 is a schematic diagram of a method for manufacturing a pouch-type battery case according to a second embodiment.
[31]
3 is a schematic diagram of a method for manufacturing a pouch-type battery case according to a third embodiment.
[32]
4 is a perspective view of a pouch-type battery case manufactured according to the manufacturing method of FIG. 1 .
Modes for carrying out the invention
[33]
Hereinafter, embodiments in which those skilled in the art can easily practice the present invention will be described in detail with reference to the accompanying drawings. However, when it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention in describing the operating principle of the preferred embodiment of the present invention in detail, the detailed description thereof will be omitted.
[34]
In addition, the same reference numerals are used throughout the drawings for parts having similar functions and functions. Throughout the specification, when it is said that a part is connected to another part, it includes not only a case in which it is directly connected, but also a case in which it is indirectly connected with another element interposed therebetween. In addition, the inclusion of a certain component does not exclude other components unless otherwise stated, but means that other components may be further included.
[35]
Descriptions that limit or add elements are applicable to all inventions unless there are special limitations, and are not limited to specific inventions.
[36]
The present invention will be described along with detailed examples according to the drawings.
[37]
1 is a schematic diagram of a method for manufacturing a pouch-type battery case according to a first embodiment.
[38]
Referring to FIG. 1 , the laminate sheet 110 for a pouch-type battery case includes an outer coating layer 101 , a metal layer 102 and an inner adhesive layer 103 , and in some cases, between the outer coating layer and the metal layer, and between the metal layer and the inside An adhesive layer may be further included between the adhesive layers.
[39]
After the laminate sheet 110 for a pouch-type battery case is placed on the first lower molding die 121, the laminate sheet 110 is pressed with the first upper molding die 131 to vent the electrode assembly receiving part 112. The induction part 113 is molded.
[40]
The first upper molding frame 131 has a size corresponding to the bottom of the electrode assembly receiving part 112 on a lower surface, and a groove 135 is formed on the lower surface. The first lower forming die 121 is a position corresponding to the groove 135 of the first upper forming die 131 , and a protrusion 125 is formed on the upper surface.
[41]
The groove 135 of the first upper forming die 131 is formed in the center of the lower surface of the first upper forming die 131 , and the protrusion 125 of the first lower forming die 121 is formed in the first lower forming die 121 . ) is formed in the center of the upper surface.
[42]
Accordingly, in the pouch-type battery case 111 manufactured through the above process, the venting induction part 113 is formed at the center of the bottom of the electrode assembly accommodating part 112 .
[43]
In general, when the battery case expands due to an increase in the internal pressure of the lithium secondary battery, it is preferable that the venting induction part is formed in the center of the electrode assembly receiving part, considering that venting is made at the portion where the pressure is concentrated. Accordingly, the protrusions 125 may be formed in a plurality of numbers, and in particular, the plurality of protrusions may be formed to be concentrated in the center of the lower molding frame.
[44]
In the present invention, the projection 125 of the lower molding frame is inserted into the groove 135 of the upper molding frame, and the groove 135 and the projection 125 have sizes and shapes corresponding to each other.
[45]
For example, the shape of the protrusion 125 may be any one of a polygonal pyramid, a polygonal truncated cone, a cone, a truncated cone, and a hemisphere, and more specifically, a hemispherical shape.
[46]
The step of forming the venting induction part of the process (c) may proceed as a process of punching the laminate sheet 110 with the first upper molding die 131, and the metal layer 102 of the laminate sheet 110 in the venting induction part. In order to reduce the thickness, the punching process may be repeated a plurality of times.
[47]
As described above, the pouch-type battery case 111 in which the electrode assembly accommodating part and the venting induction part are molded is removed from the first lower molding frame 121 .
[48]
As described above, in the pouch-type battery case according to the present invention, the thickness of the metal layer in the venting induction part is formed thinner than the thickness of the bottom of the electrode assembly accommodating part except for the venting induction part. When the internal pressure of the lithium secondary battery increases, the pressure in the venting induction part As this concentration is concentrated, it can break quickly and release gas.
[49]
Therefore, since the venting induction part is ruptured in advance before an explosion due to an increase in the internal pressure of the lithium secondary battery occurs, the safety of the lithium secondary battery can be secured.
[50]
In addition, when the molding of the electrode assembly accommodating part and the molding of the venting induction part are carried out at the same time as in the pouch-type battery case manufacturing method shown in FIG. can be reduced and productivity can be improved.
[51]
2 is a schematic diagram of a method for manufacturing a pouch-type battery case according to a second embodiment.
[52]
In the pouch-type battery case manufacturing method of FIG. 2, unlike the pouch-type battery case manufacturing method of FIG. 1, the step (b) of forming the electrode assembly receiving part and the step (c) of forming the venting induction part are sequentially performed.
[53]
Specifically, referring to FIG. 2 , after placing the laminate sheet 210 on the second lower molding die 222 , the laminate sheet 210 is pressed with the second upper molding die 232 to receive the electrode assembly. (212) is molded.
[54]
Thereafter, the pouch-type battery case in which the electrode assembly accommodating part 212 is molded is placed on the first lower mold 221 in which the protrusions 225 are formed, and the first upper mold 231 in which the groove 235 is formed. By pressing the pouch-type battery case 211 with a furnace, the venting induction part 213 is molded.
[55]
The molding method of the venting guide part is the same as described in the description of FIG. 1 .
[56]
In addition, each of the first lower forming die 221 and the first upper forming die 231 includes the first lower forming die 121 and the first upper forming die 131 and the groove and protrusion structures described in the description of FIG. Since they are the same in terms of their positions and shapes, their descriptions will be omitted below.
[57]
In the case of sequentially performing the molding of the electrode assembly receiving part and the forming of the venting inducing part as in the pouch-type battery case manufacturing method shown in FIG. 2, the laminate sheet is primarily stretched when the electrode assembly receiving part is formed. Since the venting guide part is formed, the process of punching the laminate sheet with the first upper molding die can be independently performed several times, so that the thickness of the metal layer of the laminate sheet can be formed thinner, and the thickness deviation of the metal layer can be reduced.
[58]
3 is a schematic diagram of a method for manufacturing a pouch-type battery case according to a third embodiment.
[59]
Referring to FIG. 3 , in the method for manufacturing a pouch-type battery case shown in FIG. 3 , as in the method shown in FIG. 1 , the step (b) of forming the electrode assembly receiving part and the step (c) of forming the venting induction part are performed simultaneously. .
[60]
Accordingly, the first lower mold 321 shown in FIG. 3 has a protrusion 325 formed on the upper surface, and the first upper mold 331 has a structure in which the groove 335 is formed on the lower surface.
[61]
In addition, the pouch-type battery case 311 has a structure in which a venting guide part 315 and a venting guide part 314 are formed in each of the upper case 311a and the lower case 311b, and the first lower molding frame 321 is, In the laminate sheet, projections 325 are formed in each of the portions where the upper case scheduled portion and the lower case scheduled portion are disposed, and two first upper molding molds 331 are lowered to form the laminate sheet at positions corresponding to the projections. Punch.
[62]
4 is a perspective view of a pouch-type battery case manufactured according to the manufacturing method of FIG. 1 .
[63]
4, the pouch-type battery cell 100 has a structure in which an electrode assembly accommodating part 112 is formed on either one of an upper case and a lower case, and a venting induction part ( 113) is formed.
[64]
In the venting induction part, since the thickness of the laminate sheet metal layer is formed to be thinner than the thickness of the portion excluding the venting inducing part at the bottom of the electrode assembly receiving part, the venting inducing part, which has weak physical strength, is broken first when the battery case is expanded.
[65]
In addition, the venting pressure of the venting induction part 113 is smaller than the venting pressure of the upper case and lower case sealing parts which are heat-sealed. Therefore, when the internal pressure of the pouch-type battery cell increases, the venting guide part is first broken before the upper case and lower case sealing parts are vented.
[66]
As described above, the pouch-type battery case manufacturing method according to the present invention includes a venting induction part as a structure for securing the safety of the pouch-type battery cell, and since the forming process of the venting inducing part is included in the pouch-type battery case molding process, It is possible to improve the safety of the pouch-type battery cell without increasing the manufacturing step of the pouch-type battery case.
[67]
Those of ordinary skill in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.
[68]
(Explanation of symbols)
[69]
100: pouch-type battery cell
[70]
101: outer coating layer
[71]
102: metal layer
[72]
103: inner adhesive layer
[73]
110, 210, 310: laminate sheet
[74]
111, 211, 311: pouch-type battery case
[75]
112, 212: electrode assembly receiving part
[76]
112a: the bottom of the electrode assembly accommodating part
[77]
113, 213, 314, 315: venting guide part
[78]
121, 221, 321: first lower molding frame
[79]
125, 225, 325: bump
[80]
131, 231, 331: first upper forming mold
[81]
135, 235, 335: Home
[82]
222: second lower forming mold
[83]
232: second upper forming mold
[84]
311a: upper case
[85]
311b: lower case
Industrial Applicability
[86]
As described above, in the pouch-type battery case manufacturing method according to the present invention, the manufacturing process can be simplified because the venting guide part is formed during the process of forming the battery case.
[87]
In addition, when the pouch-type battery case according to the present invention expands due to an increase in internal pressure, since the venting induction part is broken, the explosion of the pouch-type secondary battery can be prevented in advance.

Claims

[Claim 1]
(a) placing a laminate sheet for a pouch-type battery case on the lower molding frame; (b) forming an electrode assembly receiving part by pressing the laminate sheet with an upper molding die; (c) forming a venting induction part on the bottom of the electrode assembly receiving part; and (d) removing the pouch-type battery case in which the electrode assembly accommodating part and the venting induction part are molded from the lower molding frame; A pouch-type battery case manufacturing method comprising a.
[Claim 2]
The method according to claim 1, wherein the steps (b) and (c) are performed simultaneously, and the upper molding frame has a size corresponding to that of the bottom of the electrode assembly receiving part, and a groove is formed on the lower surface. A method of manufacturing a pouch-type battery case, wherein the first upper forming frame is a first lower forming frame with a protrusion formed on an upper surface corresponding to the groove of the first upper forming frame.
[Claim 3]
The second upper molding mold according to claim 1, wherein the steps (b) and (c) are sequentially performed, and in the step (b), the size of the lower surface corresponds to the bottom of the electrode assembly accommodating part. And using a second lower molding die, the step (c), the size of the lower surface is made of a size corresponding to the bottom of the electrode assembly receiving portion, the first upper molding frame is formed with a groove on the lower surface, and, 1 A method for manufacturing a pouch-type battery case using a first lower molding die having a protrusion formed on an upper surface corresponding to a groove of the upper molding die.
[Claim 4]
The method of claim 2 or 3, wherein the groove is formed in the center of the first upper molding frame.
[Claim 5]
[4] The structure of claim 2 or 3, wherein the projection is inserted into the groove, and the groove and the projection have sizes and shapes corresponding to each other, and the shape of the projections is a polygonal pyramid, a polygonal truncated cone, a cone, a truncated cone, and A method of manufacturing a pouch-type battery case in any one of the hemispheres.
[Claim 6]
The method of claim 5, wherein the protrusion is formed such that a plurality of protrusions are concentrated in the center of the lower molding frame.
[Claim 7]
According to claim 1, wherein the step (c) is a pouch-type battery case manufacturing method is performed a plurality of times in order to thin the thickness of the metal layer of the venting induction part.
[Claim 8]
The method of claim 7, wherein step (c) comprises punching the laminate sheet a plurality of times.
[Claim 9]
It consists of an upper case and a lower case including an outer coating layer, a metal layer, and an inner adhesive layer, and at least one of the upper case and the lower case has an electrode assembly receiving part formed therein, and a venting induction part is formed in the electrode assembly receiving part, A pouch-type battery case.
[Claim 10]
The pouch-type battery case according to claim 9, wherein a thickness of the metal layer in the vent induction part is thinner than a thickness of a bottom of the electrode assembly accommodating part except for the vent induction part.
[Claim 11]
The pouch-type battery case according to claim 9, wherein the venting inducing part is formed in the center of the bottom of the electrode assembly accommodating part.
[Claim 12]
The pouch-type battery case according to claim 9, wherein the venting pressure of the venting inducing part is smaller than the venting pressure of the upper case and lower case sealing parts which are heat-sealed.
[Claim 13]
A pouch-type battery cell comprising the pouch-type battery case according to any one of claims 9 to 12.