Method for manufacturing a secondary battery, manufacturing apparatus, and secondary battery manufactured thereby

Abstract

The present invention relates to a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured thereby, and relates to a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured thereby, in which no defects such as damage or disconnection of an electrode tab occur during the process of connecting the electrode tab and the electrode lead of an electrode assembly by welding, and excellent quality is realized by preventing welding defects such as weak welding or over-welding.

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2022 - 0093537 filed on July 27, 2022, and Korean Patent Application No. 10 - 2023 - 0093435 filed on July 18, 2023, and all the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference in their entirety.

[0002] The present invention relates to a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured thereby, and relates to a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured thereby, in which no defects such as damage or disconnection of an electrode tab occur during the process of connecting the electrode tab and the electrode lead of an electrode assembly by welding, and excellent quality is achieved without occurrence of welding defects such as weak welding or over - welding.

Background Art

[0003] Recently, due to the depletion of fossil fuels, the price of energy sources has increased, and concerns about environmental pollution have amplified. The demand for environmentally friendly alternative energy sources has become an essential and indispensable factor for future life. Therefore, research on various power generation technologies such as solar power, wind power, and tidal power has continued, and power storage devices such as batteries for more efficiently using the electrical energy produced in this way have also received great and continuous attention.

[0004] Furthermore, with the development of technologies and the increase in demand for electronic mobile devices and electric vehicles using batteries, the demand for batteries as an energy source has increased rapidly, and accordingly, many studies have been conducted on batteries that can meet various requirements.

[0005] Secondary batteries have received much attention as an energy source in a variety of product groups such as mobile devices and electric vehicles. Such secondary batteries are excellent energy resources that can replace the use of existing products that use fossil fuels, and are in the spotlight as environmentally friendly energy sources that do not generate by-products due to energy use.

[0006] FIG. 1 is a side view showing a process of connecting an electrode tab and an electrode lead in a conventional method for manufacturing a secondary battery.

[0007] Referring to FIG. 1, in a conventional method for manufacturing a secondary battery, the process of connecting an electrode tab and an electrode lead was performed through a pre-welding stage (see (1) in FIG. 1) first, and then through a main welding stage (see (2) in FIG. 1).

[0008] The pre-welding stage (see (1) in FIG. 1) is a stage of collecting a plurality of electrode tabs extending from the electrodes of the electrode assembly and joining them to each other through ultrasonic welding. Through this, an electrode tab assembly can be formed. The pre-welding was a method in which a plurality of electrode tabs were arranged between an upper horn and a lower anvil, and ultrasonic vibration B was applied to the horn while physically pressing through the horn and the anvil.

[0009] The main welding stage (see (2) in FIG. 1) is a stage of joining an electrode lead to the collected electrode tab assembly. In this stage, laser welding was performed with a laser welder to connect the electrode tab and the electrode lead.

[0010] In such a conventional method, there were the following problems. First, in the pre-welding method, since physical pressure is applied to the electrode tab with a horn and anvil, and ultrasonic vibration is applied to the horn, there was inevitably a problem of damaging the electrode tab. And, during ultrasonic welding, there were problems such as poor welding such as weak welding and over-welding due to abnormalities in welding conditions such as energy, power, welding time, and pressing force. Also, there were problems of poor welding and disconnection failure of the electrode tab due to the horizontal deviation of the horn and anvil or abnormal lamination during welding.

[0011] And, there was an inevitable problem that occurred due to using the horn and anvil for ultrasonic welding. Specifically, there was a problem that it was necessary to manage the replacement cycle due to wear of the horn and anvil, and there was a risk of disconnection of the electrode tab due to the radius of curvature (edge R) of the edges of the horn and anvil. Also, there was a risk of poor welding due to poor condition of the ultrasonic welder.

[0012] And, in the main welding stage, when the electrode lead overlaps the electrode tab, there is a problem that the corner of the electrode lead presses the electrode tab and damages the electrode tab, and there is also a problem that a pressing mark is generated on the electrode tab by a laser mask jig during laser welding.

Summary of the Invention

Problems to be Solved by the Invention

[0013] The present invention has been devised to solve the above problems, and the object of the present invention is to prevent defects such as damage or disconnection of the electrode tab during the process of connecting the electrode tab and the electrode lead of the electrode assembly by welding, and to provide a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured thereby, in which excellent quality is realized without occurrence of welding defects such as weak welding or over-welding.

Means for Solving the Problems

[0014] The method for manufacturing a secondary battery according to the present invention relates to a method for manufacturing a secondary battery in which a plurality of electrode tabs extending from one end of an electrode assembly formed by laminating an electrode and a separator are welded to an electrode lead, and includes: (a) preparing a tape having a required size and shape; (b) collecting a plurality of electrode tabs to form an electrode tab laminate; (c) taping the tape to the electrode tab laminate; and (d) welding the electrode tab laminate to which the taping has been completed to the electrode lead.

[0015] Between step (c) and step (d), it may further include a cutting step of cutting one side end of the electrode tab laminate to which the taping has been completed.

[0016] The step of preparing the tape may be a step of preparing the tape by cutting the tape into a required size and shape.

[0017] The step of forming the electrode tab laminate may be a step of collecting the electrode tabs by pressing or guiding a plurality of electrode tabs from above and below the electrode tabs to form the electrode tab laminate.

[0018] In the step of taping, the tape may be attached to both side ends of the electrode tab laminate with reference to the width direction of the electrode tab laminate.

[0019] In the step of taping, the tape may be attached while surrounding the upper surface, side surface, and lower surface of the electrode tab laminate.

[0020] In the step of taping, the tape may not be attached to the portions where the electrode lead is welded on the upper surface and the lower surface of the electrode tab laminate.

[0021] The step of taping may be to attach the tape to both side ends of the electrode tab laminate with reference to the width direction of the electrode tab laminate, and attach the tape to the electrode tab laminate so that a surplus portion protruding further outside the width direction end of the electrode tab laminate is formed.

[0022] (c) In the taping step, the surplus portion may be formed so as to have a form in which a part of the tape located further outside than the widthwise end of the electrode tab laminate and the other part of the tape face each other and are adhered.

[0023] (b) and (c) steps may proceed together.

[0024] (d) The step of welding the electrode lead may be to weld the electrode tab laminate and the electrode lead by laser welding.

[0025] (d) The step of welding the electrode lead may be to hold the surplus portions located on both sides of the electrode tab laminate with a clamping device and weld the electrode tab laminate and the electrode lead while pulling on both sides with reference to the width direction of the electrode tab laminate.

[0026] The manufacturing apparatus for a secondary battery according to the present invention relates to a manufacturing apparatus for a secondary battery that welds a plurality of electrode tabs extending from one end of an electrode assembly formed by laminating an electrode and a separator membrane to an electrode lead, and includes a tape cutting unit that cuts a tape into a required size and shape, a tab guide that collects a plurality of electrode tabs to form an electrode tab laminate, a tape applicator that tapes the tape cut to the electrode tab laminate, and a laser welder that welds the electrode tab laminate after taping and the electrode lead.

[0027] The tape applicator may tape the tape to the electrode tab laminate and be adhered while surrounding the upper surface, side surface, and lower surface of the electrode tab laminate.

[0028] The tape applicator can tape the tape to the electrode tab laminate and adhere the tape to the electrode tab laminate so that a surplus portion protruding further outside than the widthwise end of the electrode tab is formed.

[0029] The manufacturing apparatus may further include a clamping device that pulls the surplus portions located on both sides of the electrode tab laminate to both sides with reference to the width direction of the electrode tab laminate.

[0030] It can further include a cutter for cutting one side end of the electrode tab laminate on which taping has been completed by a tape applicator.

[0031] The secondary battery according to the present invention includes an electrode assembly formed by laminating an electrode and a separator, a pouch that houses the electrode assembly in an internal space, a plurality of electrode tabs that extend from one side end of the electrode assembly and are collected inside the pouch to form an electrode tab laminate, a tape that surrounds the electrode tab laminate; and an electrode lead having one side connected to the electrode tab laminate and the other side protruding outside the pouch.

[0032] The tape may be attached to both side ends of the electrode tab laminate with reference to the width direction of the electrode tab laminate.

[0033] The tape may be attached to both side ends of the electrode tab laminate with reference to the width direction of the electrode tab laminate, and may include an excess portion that protrudes further outside than the width direction W end of the electrode tab laminate.

[0034] The excess portion may have a form in which a part of the tape located further outside than the width direction W end of the electrode tab laminate and another part of the tape face each other and are adhered.

Advantages of the Invention

[0035] In the manufacturing method, manufacturing apparatus, and secondary battery manufactured thereby according to the present invention, defects such as damage or disconnection of the electrode tabs do not occur during the process of connecting the electrode tabs and the electrode leads of the electrode assembly by welding, and excellent quality can be realized by preventing welding defects such as weak welding or over-welding.

Brief Description of the Drawings

[0036]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0037] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention may be realized in various different forms and is not limited or restricted by the following embodiments.

[0038] To clearly explain the present invention, detailed descriptions of parts not related to the explanation or known technologies related that may obscure the gist of the present invention are omitted. When assigning reference numerals to the components of each drawing in this specification, the same or similar reference numerals are assigned to the same or similar components throughout the specification.

[0039] In addition, the terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings. The inventors should interpret them according to the principle that they can appropriately define the concept of the terms in order to explain their invention in the best way, and should interpret them in meanings and concepts consistent with the technical idea of the present invention.

[0040] Example 1 FIG. 2 is a side view showing a step of connecting an electrode tab and an electrode lead by a method for manufacturing a secondary battery according to Example 1 of the present invention. FIG. 3 is a side view showing a step of connecting an electrode tab and an electrode lead according to a modified example of Example 1 of the present invention. FIG. 4 is a perspective view showing a state where a tape is attached to an electrode tab laminate. FIG. 5 is a perspective view showing a state where one end portion of the electrode tab laminate is cut.

[0041] Referring to FIG. 2, the method for manufacturing a secondary battery according to Example 1 of the present invention may relate to a method for manufacturing a secondary battery in which a plurality of electrode tabs 20 extending from one end of an electrode assembly 10 formed by laminating an electrode and a separator are welded to an electrode lead 40. The electrode assembly 10 is formed by alternately laminating an electrode and a separator, and the electrode tab 20 may be a metal tab connected to the electrode and protruding from one side of the electrode. Therefore, the plurality of electrode tabs 20 may have a structure extending from one end of the electrode assembly 10. A secondary battery may be manufactured by bonding the laminate formed by combining the plurality of electrode tabs 20 to the electrode lead 40 again.

[0042] The method for manufacturing a secondary battery according to Example 1 of the present invention as described above may include (a) a step of preparing a tape, (b) a step of forming an electrode tab laminate, (c) a step of taping the tape, and (d) a step of welding the electrode lead.

[0043] (a) The step of preparing the tape may be a step of preparing the tape 31 having a required size and shape. The (a) drawing of FIG. 2 shows this step. In this step, the tape 31 can be cut using a tape cutting unit (not shown) that cuts the tape 31. The tape 31 can be prepared by cutting the tape 31 into a required size and shape using the tape cutting unit.

[0044] The (a) drawing of FIG. 2 shows the tape 31 after cutting is completed. Here, the tape 31 having a required size and shape can be meant to be the size and shape required for attaching the tape 31 so that the electrode tabs 20 are gathered in a lump in a state where the electrode tabs 20 are gathered. On the other hand, the step of cutting and preparing the (a) tape 31 does not necessarily have to be performed first, and may be performed at any stage as long as it is performed before the step of (c) taping the tape described below.

[0045] (b) The step of forming the electrode tab laminate may be a step of gathering a plurality of electrode tabs 20 to form the electrode tab laminate 30. The (b) drawing of FIG. 2 shows this step. This step may be performed using a tab guide 110 that gathers a plurality of electrode tabs 20 to form the electrode tab laminate 30. Referring to the (b) drawing of FIG. 2, the tab guide 110 can gather the electrode tabs 20 by descending from above and below the electrode tabs 20 in the direction of the electrode tabs 20. The tab guide 110 can form the electrode tab laminate 30 by applying pressure or guiding a plurality of electrode tabs 20 above and below the electrode tabs 20 to gather the electrode tabs 20.

[0046] And the end of the tab guide 110 can have a round shape. Such a shape can prevent damage to the electrode tabs 20 from occurring during the process of the tab guide 110 applying pressure from above and below to a plurality of electrode tabs 20 to gather the electrode tabs 20.

[0047] (c) The taping step may be a step of taping the tape 31 to the electrode tab laminate 30. This step may be a step of maintaining a stable shape so that the collected electrode tab laminate 30 does not move or collapse. This may be a step of collecting the electrode tabs 20 so that welding is easy in a subsequent step of welding the electrode leads 40.

[0048] Drawing (c) of FIG. 2 shows this step. And FIG. 4 shows a state in which the tape 31 is attached to the electrode tab laminate 30 in step (c). Referring to drawing (c) of FIG. 2 and FIG. 4, in the step of (c) taping, with reference to the width direction W of the electrode tab laminate 30, the tape 31 may be attached to both side ends of the electrode tab laminate 30. And being attached to both side ends, and the tape 31 may be attached while surrounding the upper surface, side surface, and lower surface of the electrode tab laminate 30. It may be attached in a taut state with tension applied to firmly collect the electrode tabs 20, or may be attached with an appropriate strength so as not to be too tight. Referring to FIG. 4, the tape 31 may be attached to the horizontal portion among the portions where the electrode tabs 20 are collected, and may also be partially attached to the inclined portion connecting from the horizontal portion in the direction of the electrode assembly.

[0049] And in the step of (c) taping, the tape 31 is attached to the upper surface or the lower surface of the electrode tab laminate 30, but may not be attached to the portion where the electrode lead 40 is welded. Thus, a welding region A may be formed where the electrode lead 40 is welded at a portion where the tape 31 is not attached (see FIG. 6). Since the surface where the tape 31 is present becomes a surface where welding is not suitable, it may be that the tape 31 is not attached to the surface where welding is performed. When attaching the tape 31, a tape applicator 120 for taping the tape 31 cut to the electrode tab laminate 30 can be used.

[0050] Here, the tape applicator 120 may basically function to attach the cut tape 31 to the electrode tab 20, but it can also be configured to have the function of cutting the tape 31. In this case, the tape applicator 120 can also function as a tape cutting unit. When using the tape applicator 120 that also functions as a tape cutting unit in this way, the operation can be simplified and made more efficient. That is, when the cutting of the tape 31 is completed, there is no need to separately move the tape 31 to another location, and it is possible to perform the operation of attaching it to the electrode tab 20 while holding it up as it is, which can be significantly more efficient.

[0051] On the other hand, the steps (b) and (c) may proceed separately, or they may proceed together. That is, when the steps of (b) forming the electrode tab laminate and (c) taping the tape are performed simultaneously, a more efficient and effective process may be possible. That is, as shown in the drawing (c) of FIG. 2, when the tape applicator 120 attaches the tape 31 to the electrode tab laminate 30 where the electrode tabs 20 are pressurized, collected, and fixed by the tab guide 110, more accurate taping may be possible.

[0052] The step of (d) welding the electrode tab laminate and the electrode lead may be a step of welding the electrode tab laminate 30 and the electrode lead 40 that are overlapped with a welding machine after the taping of the electrode tab laminate 30 is completed. It may be a step of joining the electrode tab laminate 30 and the electrode lead 40 by welding. Specifically, the step of (d) welding the electrode lead 40 may be a step of laser-welding the electrode tab laminate 30 and the electrode lead 40 by laser welding. The drawing (d) of FIG. 2 shows this step. This step may be performed using a laser welding machine 130, which is a device for irradiating the electrode tab laminate 30 and the electrode lead 40 with a laser for welding.

[0053] The state in which the electrode lead 40 is joined to the electrode tab laminate 30 by laser welding is shown in FIG. 6. Referring to FIG. 6, the welding region A where the laser welding is performed may be a region where the tape 31 is not attached. That is, as shown in FIG. 6, the welding region A may be the central region on the upper surface of the electrode tab laminate 30. Of course, the electrode lead 40 is not limited to being welded to the upper surface of the electrode tab laminate 30, and the electrode lead 40 may be welded to the lower surface of the electrode tab laminate 30.

[0054] Thus, according to the manufacturing method and manufacturing apparatus of the secondary battery according to Example 1 of the present invention, since the tape 31 is used unlike the conventional pre-welding method, the manufacturing of the secondary battery can proceed without damaging the electrode tab 20. And since ultrasonic welding itself is not performed, problems such as welding defects due to ultrasonic welding can be basically solved. For example, welding defects due to the level deviation between the horn and the anvil or lamination abnormalities during welding, and disconnection defects of the electrode tab 20 can be prevented from occurring. Of course, since ultrasonic welding is not used, various problems caused by the use of an ultrasonic welder can also be prevented from occurring.

[0055] When the method of collecting the electrode tabs 20 using the tape 31 according to Example 1 of the present invention is adopted, the electrode tabs 20 can be collected quickly and efficiently, and the main welding between the electrode lead 40 and the electrode tab 20 can be performed efficiently and easily. Also, the electrode tabs 20 can be collected to ensure a good length margin of the electrode tabs 20.

[0056] And in the main welding stage, when the electrode lead 40 overlaps the electrode tab 20, the problem that the corner of the electrode lead 40 presses the electrode tab 20 and causes damage to the electrode tab 20 can be reduced. Since the tape 31 covers and protects the surface of the electrode tab 20, no damage can occur even if the corner touches that part. Also, the problem of indentation damage to the electrode tab 20 caused by a laser mask jig during laser welding can be prevented.

[0057] On the one hand, Example 1 of the present invention may be implemented in a further modified form. FIG. 3 is a side view showing the step of connecting the electrode tab 20 and the electrode lead 40 according to a modification of Example 1 of the present invention.

[0058] Referring to FIG. 3, in a modification of Example 1 of the present invention, a (c-1) cutting step may be further included between the (c) step and the (d) step.

[0059] Specifically, the (c-1) cutting step may be a step of cutting one side end of the electrode tab laminate 30 on which the taping is completed. Drawing (c-1) of FIG. 3 shows this step. The modification of Example 1 of the present invention is the same as Example 1 of FIG. 2 in the remaining steps, except that there is a difference in that a (c-1) cutting step is further included between the (c) step of taping the tape and the (d) step of welding the electrode tab laminate and the electrode lead. The (c-1) cutting step may be performed using a cutter 140. At this time, the cutter 140 can cut one side end of the electrode tab laminate 30 on which the taping is completed by the tape applicator 120 to an appropriate length.

[0060] When cutting the electrode tab laminate 30 to an appropriate length, the efficiency of the laser welding operation can be increased by making it an appropriate length for laser welding. There is also an effect that the length of the electrode tab laminate 30 can be adjusted to fit the size of the final product of the secondary battery. Also at this time, the method of fixing the electrode tab 20 with the tape 31 of the present invention can fix the electrode tab 20 so that the cutting of the electrode tab 20 is easy.

[0061] FIG. 5 shows a state in which one side end of the electrode tab laminate 30 is cut by the cutter 140. FIG. 5 shows a shape in which the electrode tab laminate 30 is neatly cut along the cutting line L. In FIG. 5, the central region of the upper surface of the electrode tab 20 to which the tape 31 is not attached can be the laser welding region A where the electrode lead 40 is welded. After the cutting operation, welding can be accurately performed on this welding region A.

[0062] On the one hand, a manufacturing apparatus for a secondary battery may be required to implement the method for manufacturing a secondary battery according to Example 1 of the present invention. This manufacturing apparatus for a secondary battery may be a manufacturing apparatus for a secondary battery that welds a plurality of electrode tabs 20 extending from one end of an electrode assembly 10 formed by laminating an electrode and a separator to an electrode lead 40.

[0063] The manufacturing apparatus for a secondary battery for implementing the method for manufacturing a secondary battery according to Example 1 of the present invention may include a tape cutting unit (not shown), a tab guide 110, a tape applicator 120, and a laser welder 130.

[0064] The tape cutting unit may be configured to cut the tape 31 into a required size and shape. The tab guide 110 may be configured to collect a plurality of electrode tabs 20 to form an electrode tab laminate 30. The tape applicator 120 may be configured to tape the cut tape 31 to the electrode tab laminate 30. And the laser welder 130 may be configured to weld the electrode tab laminate 30 with the tape applied thereto and the electrode lead 40. Here, the tape applicator 120 may have the function of the tape cutting unit. And according to a modification of Example 1 of the present invention, the manufacturing apparatus for a secondary battery may further include a cutter 140 that cuts one side end of the electrode tab laminate 30 that has been taped by the tape applicator 120.

[0065] Example 2 FIG. 6 is a perspective view showing the internal form of a secondary battery according to Example 2 of the present invention.

[0066] Example 2 of the present invention differs from Example 1 in that it relates to a secondary battery manufactured by the method for manufacturing a secondary battery of Example 1.

[0067] The content common to Example 1 will be omitted as much as possible, and Example 2 will be described centering on the differences. That is, it is self-evident that when the content not described in Example 2 is required, it may be supplemented through the content of Example 1.

[0068] Referring to FIG. 6, the secondary battery according to Embodiment 2 of the present invention may include an electrode assembly 10, a pouch, an electrode tab laminate 30, an electrode lead 40, and a tape 31.

[0069] The electrode assembly 10 may have a laminate structure in which electrodes and a separator are laminated. The pouch (not shown) may be configured to accommodate the electrode assembly 10 in an internal space. The electrode tab laminate 30 may be formed by collecting a plurality of electrode tabs 20 that extend from one end portion of the electrode assembly 10 and are located inside the pouch. The tape 31 may be configured to surround the electrode tab laminate 30. Here, the tape 31 may be attached to both end portions of the electrode tab laminate 30 with reference to the width direction W of the electrode tab laminate 30.

[0070] Attached to both end portions, and the tape 31 may be attached while surrounding the upper surface, side surface, and lower surface of the electrode tab laminate 30. It may be attached in a taut state with tension applied to firmly collect the electrode tabs 20, or may be attached with an appropriate strength so as not to be too tight. Based on the side view, the tape 31 may be attached to the horizontal portion among the portions where the electrode tabs 20 are collected, and may also be partially attached to the inclined portion connected in the electrode direction from the horizontal portion. That is, the thickness of the electrode tab laminate 30 may be constant in the horizontal portion but may become thicker in the inclined portion, and the tape 31 may be attached to a part of the horizontal portion and the inclined portion.

[0071] And the tape 31 may not be attached to the portions where the electrode lead 40 is welded on the upper and lower surfaces of the electrode tab laminate 30. In this way, a welding region A where the electrode lead 40 is welded may be formed at a portion where the tape 31 is not attached (see FIG. 6). Since the place where the tape 31 is attached should be a surface where welding is incompatible, the tape 31 is not attached to the surface where welding is performed.

[0072] The electrode lead 40 may be configured such that one side is connected to the electrode tab laminate 30 and the other side protrudes outside the pouch (not shown). One side of the electrode lead 40 may be laser-welded to the electrode tab laminate 30 in the welding region A. Then, welding can be performed excluding the region where the lead film 41 is attached.

[0073] And, the secondary battery according to Embodiment 2 of the present invention as described above may be a secondary battery with excellent quality by exhibiting various effects of the invention described in Embodiment 1.

[0074] Embodiment 3 FIG. 7 is a side view showing a process of connecting an electrode tab and an electrode lead by a method for manufacturing a secondary battery according to Embodiment 3 of the present invention. FIG. 8 is a perspective view showing a state in which a tape is attached to an electrode tab laminate in Embodiment 3 of the present invention. FIG. 9 is a cross-sectional view showing the principle of forming an excess portion of the tape in Embodiment 3 of the present invention. FIG. 10 is a perspective view showing a state in which one end portion of an electrode tab laminate is cut in Embodiment 3 of the present invention.

[0075] Embodiment 3 is different from Embodiments 1 and 2 in that when attaching a tape to the electrode tab laminate, the tape is attached so that excess portions are formed on both sides of the electrode tab.

[0076] The content common to Embodiments 1 and 2 will be omitted as much as possible, and Embodiment 3 will be described centering on the differences. That is, it is obvious that if the content not described in Embodiment 3 is necessary, it may be supplemented through the content of Embodiments 1 and 2.

[0077] Referring to FIG. 7, the method for manufacturing a secondary battery according to Embodiment 3 of the present invention may also relate to a method for manufacturing a secondary battery in which a plurality of electrode tabs 20 extending from one end of an electrode assembly 10 formed by laminating an electrode and a separator are welded to an electrode lead 40.

[0078] The electrode assembly 10 may be formed by alternately laminating electrodes and separator membranes, and the electrode tab 20 may be a metal tab connected to the electrode and protruding from one side of the electrode. Therefore, the plurality of electrode tabs 20 may have a structure extended from one end of the electrode assembly 10. A secondary battery may be manufactured by bonding the laminate formed by combining the plurality of electrode tabs 20 to the electrode lead 40 again.

[0079] Such a method for manufacturing a secondary battery according to Embodiment 3 of the present invention may include (a) a step of preparing a tape, (b) a step of forming an electrode tab laminate, (c) a step of taping the tape, and (d) a step of welding an electrode lead.

[0080] Of course, in the case of Embodiment 3, a (c-1) cutting step may be further included between steps (c) and (d).

[0081] Steps (a) and (b) in FIG. 7 may be as described in the aforementioned Embodiment 1.

[0082] The step of (c) taping the tape may be a step of taping the tape 31 to the electrode tab laminate 30. This step may be a step of maintaining a stable shape so that the collected electrode tab laminate 30 does not move or collapse. This may be to collect the electrode tabs 20 so that welding is easy in the subsequent step of welding the electrode lead 40.

[0083] The (c) drawing in FIG. 7 shows this step. And FIG. 8 shows a state where the tape 31 is attached to the electrode tab laminate 30 in step (c). Referring to the (c) drawing in FIG. 7 and FIG. 8, in the step of (c) taping, the tape 31 may be attached to both end portions of the electrode tab laminate 30 with reference to the width direction W of the electrode tab laminate 30.

[0084] In the method for manufacturing a secondary battery according to Embodiment 3 of the present invention, the tape 31 may be attached to the electrode tab laminate 30 such that an excess portion 31-1 protruding further outside than the end portion in the width direction W of the electrode tab laminate 30 is formed.

[0085] In the cross-sectional view of FIG. 9, the principle of forming the surplus portion 31-1 is shown. First, referring to the drawing on the left side of the arrow in FIG. 9, the tape 31 can be attached while surrounding the side portion of the electrode tab laminate 30 such that there is a portion remaining further outside the end of the electrode tab with reference to the width direction W of the electrode tab laminate 30. Then, after attaching the tape 31 in this way, a process of applying forces (E1, E2) from above and below to the remaining portion on the outside and attaching the upper tape and the lower tape to each other can be passed through. In this case, as shown on the right side of the arrow in FIG. 9, the form of the tape can be formed. Here, the surplus portion 31-1 may be formed to have a form in which a part of the tape 31 located further outside the width direction end of the electrode tab laminate 30 and another part of the tape 31 face each other and are adhered.

[0086] The surplus portion 31-1 of the tape 31 can be formed in such a manner. When the formation of the surplus portion 31-1 is completed in this way, the shape of the electrode assembly as shown in FIG. 8 can be obtained.

[0087] Tension may be applied to firmly gather the electrode tabs 20 and the tape may be attached in a taut state, or it may be attached with an appropriate strength so as not to be too tight. Referring to FIG. 8, the tape 31 may be attached to the horizontal portion among the portions where the electrode tabs 20 are gathered, and may also be partially attached to the inclined portion connecting from the horizontal portion in the direction of the electrode assembly.

[0088] And in the (c) taping step, the tape 31 is attached to the upper surface or the lower surface of the electrode tab laminate 30, but does not have to be attached to the portion where the electrode lead 40 is welded. In this way, a welding region A where the electrode lead 40 is welded may be formed at the portion where the tape 31 is not attached (see FIG. 11). Since the surface where the tape 31 is located becomes a surface where welding is not suitable, the tape 31 may not be attached to the surface where welding is performed. When attaching the tape 31, a tape applicator 120 for taping the cut tape 31 to the electrode tab laminate 30 can be used.

[0089] Here, the tape applicator 120 may tape the tape 31 to the electrode tab laminate 30 and may be attached to the upper surface, side surface, and lower surface of the electrode tab laminate 30. However, in Example 3 of the present invention, the tape applicator 120 can attach the tape 31 to the electrode tab laminate 30 such that a surplus portion 31-1 protruding further outside the widthwise end of the electrode tab is formed.

[0090] Furthermore, a clamping device 150 that pulls the surplus portions 31-1 located on both sides of the electrode tab laminate to both sides with reference to the width direction W of the electrode tab laminate 30 can be included. This clamping device 150 can be mainly used at the stage of welding the electrode lead 40 described below, but can also be used at the (c) taping stage in order to tightly attach the tape 31.

[0091] On the other hand, the (b) stage and the (c) stage may proceed separately, or may proceed together. That is, when the (b) stage of forming the electrode tab laminate and the (c) stage of taping are performed simultaneously, a more efficient and effective process may be possible.

[0092] On the other hand, referring to FIG. 7, in Example 3 of the present invention, a (c-1) cutting stage can be further included between the (c) stage and the (d) stage.

[0093] Specifically, the (c-1) cutting stage may be a stage of cutting one end of the electrode tab laminate 30 on which taping has been completed. Drawing (c-1) in FIG. 7 shows this stage.

[0094] The (c-1) cutting stage may be performed using a cutter 140, and the cutter 140 can cut one end of the electrode tab laminate 30 on which taping has been completed by the tape applicator 120 to an appropriate length. In Example 3 of the present invention, the surplus portion 31-1 of the tape may also be cut during the cutting stage.

[0095] When cutting the electrode tab laminate 30 to an appropriate length, it is possible to then make it an appropriate length for laser welding to improve the efficiency of the laser welding operation. Further, there is also an effect that the length of the electrode tab laminate 30 can be adjusted to conform to the size of the final product of the secondary battery. Also at this time, the method of fixing the electrode tab 20 with the tape 31 of the present invention can fix the electrode tab 20 so that the cutting of the electrode tab 20 is easy.

[0096] In FIG. 10, a state in which one side end portion of the electrode tab laminate 30 is cut by the cutter 140 is shown. In FIG. 10, a shape in which the electrode tab laminate 30 and the surplus portion 31-1 of the tape are neatly cut along the cutting line L is shown. The central region of the upper surface of the electrode tab 20 to which the tape 31 is not attached in FIG. 10 can become the laser welding region A where the electrode lead 40 is welded. Welding can be accurately performed on this welding region A after the cutting operation.

[0097] (d) The step of welding the electrode tab laminate and the electrode lead may be a step of welding with a welding machine in a state where the electrode tab laminate 30 and the electrode lead 40 to which taping has been completed are overlapped. It may be a step of joining the electrode tab laminate 30 and the electrode lead 40 by welding. And specifically, (d) the step of welding the electrode lead 40 may be a step of laser welding the electrode tab laminate 30 and the electrode lead 40 by laser welding.

[0098] Drawing (d) of FIG. 7 shows this step. This step may be performed using a laser welding machine 130 which is a device for irradiating a welding laser to the electrode tab laminate 30 and the electrode lead 40.

[0099] And in Example 3 of the present invention, (d) in the step of welding the electrode lead 40, the surplus portions 31-1 located on both sides of the electrode tab laminate 30 are grasped by the clamping device 150, and while pulling on both sides with reference to the width direction W of the electrode tab laminate 30 (see F1, F2 in FIG. 7), the electrode tab laminate 30 and the electrode lead 40 can be welded.

[0100] In this case, the gap between the electrode tabs 20 can be eliminated. That is, the electrode tabs 20 can be in a more closely adhered state. When welding is performed in a state where such tension is applied, the welding quality between the electrode tab laminate 30 and the electrode lead 40 can be further improved.

[0101] When the method of collecting the electrode tabs 20 using the tape 31 according to Example 3 of the present invention is adopted, the electrode tabs 20 can be quickly and effectively collected, and the main welding between the electrode lead 40 and the electrode tabs 20 can be remarkably and effectively facilitated.

[0102] Example 4 FIG. 11 is a perspective view showing the internal configuration of the secondary battery according to Example 4 of the present invention.

[0103] Example 4 of the present invention is different from Examples 1 to 3 in that it relates to a secondary battery manufactured by the method for manufacturing a secondary battery of Example 3.

[0104] The content common to Examples 1 to 3 will be omitted as much as possible, and Example 4 will be described centering on the differences. That is, it is obvious that when the content not described in Example 4 is necessary, it may be complemented through the content of Examples 1 to 3.

[0105] Referring to FIG. 11, the secondary battery according to Example 4 of the present invention can include an electrode assembly 10, a pouch, an electrode tab laminate 30, an electrode lead 40, and a tape 31.

[0106] The electrode assembly 10 may be configured as a laminate formed by laminating electrodes and a separator membrane. The pouch (not shown) may be configured to accommodate the electrode assembly 10 in an internal space. The electrode tab laminate 30 may be configured such that a plurality of electrode tabs 20 extending from one end portion of the electrode assembly 10 and positioned inside the pouch are collected. The tape 31 may be configured to surround the electrode tab laminate 30. Here, the tape 31 may be attached to both end portions of the electrode tab laminate 30 with reference to the width direction W of the electrode tab laminate 30.

[0107] The tape 31 may be attached to both end portions of the electrode tab laminate 30, and the tape 31 may include an excess portion 31-1 that protrudes further outside than the end portions in the width direction W of the electrode tab laminate 30.

[0108] This excess portion 31-1 may have a form in which a part of the tape 31 located further outside than the end portions in the width direction W of the electrode tab laminate 30 and another part of the tape 31 face each other and are adhered. The tape 31 may be attached to the upper and lower surfaces of the electrode tab laminate 30. Also, the tape may be attached to at least a part of the side surfaces of the electrode tab laminate 30 (see FIG. 9). By applying tension to the electrode tab laminate 30 by the tape 31, the state in which the electrode tabs 20 are in close contact can be maintained.

[0109] Then, the tape 31 may be attached in a taut state with tension applied to firmly collect the electrode tabs 20, and may be attached with an appropriate strength so as not to be too tight. Based on the side view, the tape 31 may be attached to the horizontal portion among the portions where the electrode tabs 20 are collected, and may also be partially attached to the inclined portion connected to the direction of the electrodes from the horizontal portion. That is, the thickness of the electrode tab laminate 30 may be constant in the horizontal portion but may become thicker in the inclined portion, and the tape 31 may be attached to a part of this horizontal portion and the inclined portion.

[0110] Then, the tape 31 does not have to be attached to the portions where the electrode leads 40 are welded on the upper and lower surfaces of the electrode tab laminate 30. A welding region A where the electrode leads 40 are welded may be formed at a portion where the tape 31 is not attached (see Fig. 11). Since the place where the tape 31 is attached should be a surface where welding is not suitable, the tape 31 is not attached to the surface where welding is performed.

[0111] One side of the electrode lead 40 may be connected to the electrode tab laminate 30, and the other side may protrude outside the pouch (not shown). One side of the electrode lead 40 may be connected to the electrode tab laminate 30 by laser welding in the welding region A.

[0112] And, the secondary battery according to Example 4 of the present invention as described above can be a secondary battery with excellent quality by exhibiting various effects of the inventions described in Examples 1 and 3.

[0113] As described above, although the present invention has been described with reference to limited examples and drawings, the present invention is not limited thereto, and various implementations are possible within the equivalent scope of the technical idea of the present invention and the claims described below by those having ordinary knowledge in the technical field to which the present invention pertains.

Explanation of Reference Numerals

[0114] 10 Electrode assembly 20 Electrode tab 30 Electrode tab laminate 31 Tape 31-1 Surplus portion 40 Electrode lead 41 Lead film 110 Tab guide 120 Tape applicator 130 Laser welder 140 Cutter 150 Clamping device L Cutting line

Claims

1. A method for manufacturing a secondary battery, comprising welding a plurality of electrode tabs extending from one end of an electrode assembly formed by laminating an electrode and a separator to an electrode lead, the method comprising: (a) preparing a tape having a required size and shape; (b) collecting the plurality of electrode tabs to form an electrode tab laminate; (c) taping the tape to the electrode tab laminate; and (d) welding the electrode tab laminate, to which the taping has been completed, to the electrode lead.

2. Between the step (c) and the step (d), the method for manufacturing a secondary battery according to claim 1, further comprising a cutting step of cutting one side end portion of the electrode tab laminate, to which the taping has been completed.

3. The step (a) of preparing the tape is a step of preparing the tape by cutting the tape to a required size and shape, the method for manufacturing a secondary battery according to claim 1.

4. The step (b) of forming the electrode tab laminate is a step of forming the electrode tab laminate by collecting the plurality of electrode tabs by pressing or guiding the plurality of electrode tabs from above and below the electrode tabs, the method for manufacturing a secondary battery according to claim 1.

5. In the step (c) of taping, with reference to the width direction of the electrode tab laminate, the tape is attached to both side end portions of the electrode tab laminate, the method for manufacturing a secondary battery according to claim 1.

6. In the step (c) of taping, the tape is attached while surrounding the upper surface, side surface, and lower surface of the electrode tab laminate, the method for manufacturing a secondary battery according to claim 5.

7. In the step (c) of taping, the tape is not attached to portions of the upper surface and the lower surface of the electrode tab laminate where the electrode lead is welded, the method for manufacturing a secondary battery according to claim 6.

8. The step (c) of taping is a step of attaching the tape to both side end portions of the electrode tab laminate with reference to the width direction of the electrode tab laminate, and attaching the tape to the electrode tab laminate such that a surplus portion protruding further outside than the width direction end portions of the electrode tab laminate is formed, the method for manufacturing a secondary battery according to claim 1.

9. In the step (c) of taping, The manufacturing method of a secondary battery according to claim 8, wherein the surplus portion is formed to have a configuration in which a part of the tape located further outside than the widthwise end of the electrode tab laminate and the other part of the tape face each other and are adhered.

10. The manufacturing method of a secondary battery according to claim 1, wherein both the step (b) and the step (c) proceed simultaneously.

11. The step of welding the (d) electrode lead The manufacturing method of a secondary battery according to any one of claims 1 to 10, wherein the electrode tab laminate and the electrode lead are welded by laser welding.

12. The step of welding the (d) electrode lead The manufacturing method of a secondary battery according to claim 8 or 9, wherein the surplus portions located on both sides of the electrode tab laminate are grasped by a clamping device, and while pulling both sides with reference to the width direction of the electrode tab laminate, the electrode tab laminate and the electrode lead are welded.

13. A manufacturing apparatus for a secondary battery that welds a plurality of electrode tabs extending from one end of an electrode assembly formed by laminating an electrode and a separator membrane to an electrode lead, A tape cutting unit that cuts a tape into a required size and shape; A tab guide that collects the plurality of electrode tabs to form an electrode tab laminate; A tape applicator that tapes the cut tape to the electrode tab laminate; and A laser welder that welds the electrode tab laminate with the tape applied thereon and the electrode lead; The manufacturing apparatus of the secondary battery containing these.

14. The tape applicator tapes the tape to the electrode tab laminate and The manufacturing apparatus of the secondary battery according to claim 13, which adheres while surrounding the upper surface, side surface, and lower surface of the electrode tab laminate.

15. The tape applicator tapes the tape to the electrode tab laminate and The manufacturing apparatus of the secondary battery according to claim 13, which attaches the tape to the electrode tab laminate so that a surplus portion protruding further outside than the widthwise end of the electrode tab is formed.

16. The manufacturing apparatus of the secondary battery according to claim 15, further including a clamping device that pulls the surplus portions located on both sides of the electrode tab laminate to both sides with reference to the width direction of the electrode tab laminate.

17. The manufacturing apparatus of the secondary battery according to any one of claims 13 to 16, further including a cutter that cuts one side end of the electrode tab laminate taped by the tape applicator.

18. An electrode assembly formed by laminating an electrode and a separator membrane; A pouch that houses the electrode assembly in an internal space; An electrode tab laminate formed by collecting a plurality of electrode tabs that extend from one end portion of the electrode assembly and are located inside the pouch; A tape surrounding the electrode tab laminate; and An electrode lead having one side connected to the electrode tab laminate and the other side protruding outside the pouch; A secondary battery comprising.

19. The tape is The secondary battery according to claim 18, which is attached to both end portions of the electrode tab laminate with reference to the width direction of the electrode tab laminate.

20. The tape is The secondary battery according to claim 18, which is attached to both end portions of the electrode tab laminate with reference to the width direction of the electrode tab laminate and includes an excess portion protruding further outside the width direction W end portion of the electrode tab laminate.

21. The secondary battery according to claim 20, wherein the excess portion has a form in which a part of the tape located further outside the width direction W end portion of the electrode tab laminate and another part of the tape face each other and are adhered.

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