Method for sealing secondary battery

Abstract

According to the present invention, the method for sealing a secondary battery is a method for sealing a battery case and an electrode lead of the secondary battery, the method comprising the steps of: providing a heater on a front surface of a sealer; disposing an electrode lead between an upper sealer and a lower sealer included in the sealers; heating an electrode lead by using the heater; sealing the electrode lead and the battery case with the sealer; shooting a sealer around the heater with a camera disposed on a front surface of the heater to obtain shape information; measuring the temperature of a sealer around the heater by using a temperature sensor to obtain temperature information; acquiring temperature-related thermal expansion data of the sealer using the shape information, temperature information, and material information of the sealer; and measuring the temperature of the electrode lead with a temperature sensor, and then using the thermal expansion data to predict a thermal expansion value of the sealer at the electrode lead covered by the heater.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0002] This application claims priority and the benefit of Korean Patent Application No. 10 - 2023 - 0137564, filed on October 16, 2023, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

[0003] The present disclosure relates to a method for sealing a secondary battery, and more particularly, to a method for sealing a secondary battery that can predict the thermal deformation amount of the gap of a sealer in an invisible region during the sealing process, thereby adjusting the gap of the sealer. Background Art

[0004] The critical - to - quality (CTQ) parameter of a secondary battery includes the sealing thickness of an electrode lead, and the critical - to - process (CTP) parameter related to the sealing thickness includes the gap adjustment of a sealer. That is, in order to seal the electrode lead of a secondary battery to an appropriate thickness, it is important to adjust the gap between an upper sealer and a lower sealer included in the sealer.

[0005] Conventionally, as shown in Figure 1 , the sealed secondary batteries 10 are sampled at regular intervals, and frequent inspections are performed to measure the thickness at multiple points on the bag - sealing portion around the electrode lead 11 and adjust the gap of the sealer. However, in the case of this method, a process of inspecting the product quality through a comprehensive inspection is required when a defect occurs, and losses of materials, labor, and time are caused during the process of inspecting the product quality. Thus, as there is an increasing need for a method of measuring and managing the gap of a sealer on an in - line basis during the sealing process without separating the sample from the process, research has been conducted on this method.

[0006] Even conventionally, attempts have been made to introduce an intelligent camera into the in - line process, but since the position of the sealer as a measurement reference is covered by a heater, there is a problem that it is difficult to take a front - view photograph using the camera. At the rear surface where the heater is not installed, it is difficult to take a photograph using the camera due to the problem of tray transportation.

[0007] Therefore, there is a need to develop a method that can measure and manage the gap of a sealer when the position of the sealer as a measurement reference is in an invisible region. Summary of the Invention

[0008] [Technical Problem]

[0009] An object of the present disclosure is to provide a sealing method that predicts the thermal deformation amount of a seal in an invisible area on an on-line basis and adjusts the gap of the seal.

[0010] An object of the present disclosure is to provide a sealing method that adjusts the gap of a seal on an on-line basis to improve reliability.

[0011] [Technical Solution]

[0012] According to the present disclosure, there is provided a method for sealing a secondary battery, the method sealing electrode leads and a battery case of the secondary battery, the method comprising the steps of: setting a heater on a front surface of a seal; setting the electrode leads between an upper seal and a lower seal of the seal; heating the electrode leads by the heater; sealing the electrode leads and the battery case by the seal; photographing the seal around the heater by a camera disposed in front of the heater to obtain shape information; measuring a temperature of the seal around the heater by a temperature sensor to obtain temperature information; using the shape information, the temperature information, and related material information of the seal to obtain thermal expansion data related to the temperature of the seal; and measuring a temperature of the electrode leads by the temperature sensor and then using the thermal expansion data to predict a thermal expansion value of the seal at the electrode leads covered by the heater.

[0013] In one embodiment, the method may further comprise the step of adjusting a gap between the upper seal and the lower seal according to the predicted thermal expansion value.

[0014] In one embodiment, the camera, the heater, and the seal are arranged in a first direction, and the seal may extend in a second direction perpendicular to the first direction.

[0015] In one embodiment, when predicting the thermal expansion value, the temperature sensor measures a temperature at a central position of the electrode leads, and the central position may be a central position of the electrode leads in the second direction.

[0016] In one embodiment, the camera may be disposed in front of the seal.

[0017] In one embodiment, the shape information may be obtained by measuring a height of the seal along a length direction of the seal.

[0018] In one embodiment, the temperature sensor may include any one of a resistance temperature detector (RTD) sensor, a thermocouple temperature sensor, and an infrared temperature sensor.

[0019] In one embodiment, the steps of heating the electrode lead and sealing the electrode lead may be performed simultaneously.

[0020] In one embodiment, the sealer may include at least one of BeCu, WC, AlBe, Inconel718, and Ni-Be.

[0021] In one embodiment, the secondary battery includes an electrode assembly accommodated in the battery case, and the electrode leads may protrude from the electrode assembly at both ends of the battery case.

[0022] [Advantageous Effects]

[0023] According to the present disclosure, it is possible to reliably predict the amount of thermal deformation of the sealer at the measurement position in the invisible region.

[0024] When applying the sealing method described in the present disclosure, it is possible to measure and manage the gap of the sealer on an on-line basis during the sealing process, thereby providing a sealing method with improved reliability and process efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a view showing a conventional method for evaluating the sealing thickness.

[0026] Figure 2 is a perspective view showing the front surface of a sealer according to an embodiment.

[0027] Figure 3 is a plan view showing the front surface of a sealer according to an embodiment.

[0028] Figure 4 is a view showing a step in a sealing method according to an embodiment.

[0029] Figure 5 is a perspective view showing a secondary battery according to an embodiment.

[0030] Figure 6 is a graph showing the results of a thermal expansion simulation according to an embodiment. DETAILED DESCRIPTION

[0031] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement them. The present disclosure can be modified in various different ways and is not limited to the embodiments described herein.

[0032] Parts not related to the description will be omitted to clearly describe the present disclosure, and throughout the description, like reference numerals denote like elements.

[0033] In addition, in the drawings, for ease of description, the dimensions and thicknesses of each element are arbitrarily shown, but the present disclosure is not necessarily limited to the dimensions and thicknesses shown in the drawings. In the drawings, for clarity, the thicknesses of layers, regions, etc. are enlarged. In the drawings, for ease of description, the thicknesses of some layers and regions are enlarged.

[0034] In addition, it can be understood that when an element such as a layer, film, region, or plate is referred to as being "on" or "above" another element, the element can be directly on the other element or there can be an intermediate element. In contrast, when an element is referred to as being "directly on another element", this means that there are no other intermediate elements. In addition, the terms "on" or "above" mean being arranged on or below the reference part, and do not mean being arranged on the upper end of the reference part in the direction opposite to gravity.

[0035] In addition, throughout the specification, when a part is referred to as "comprising" or "including" a specific component, this means that the part can further include other components without excluding other components, unless otherwise stated.

[0036] In addition, throughout the specification, when referred to as a "plane", this means when observing the target part from the upper side, and when referred to as a "cross-section", this means observing the target part from one side of a cross-section cut vertically.

[0037] Terms representing directions such as the front side, rear side, left side, right side, upper side, and lower side have been used, but the terms used are provided only for ease of description and can vary depending on the position of the object, the position of the observer, etc.

[0038] Hereinafter, preferred embodiments are presented to better understand the present disclosure. However, the following embodiments are only for illustrating the present disclosure, and the present disclosure is not limited to or restricted by these embodiments.

[0039] Figure 2 is a perspective view showing the front surface of a sealant according to an embodiment.

[0040] Figure 3 is a plan view showing the front surface of a sealant according to an embodiment.

[0041] Figure 4 is a view showing a step in a sealing method according to an embodiment.

[0042] Refer together to Figure 2 、 Figure 3 and Figure 4, a sealing device 1000 of an embodiment includes a camera 100, a sealer 200, a heater 300, a lead device 400, and a temperature sensor 500. In addition, the sealing device 1000 further includes a first rail 101, a second rail 102, and a frame portion 103 for moving the camera 100.

[0043] The camera 100 used can be a known camera including a vision sensor. The camera 100 can directly measure the measured values of the object to be photographed. Specifically, the camera 100 can reflect the intervals on the field of view by converting the intervals on the field of view (FOV) into actual measured values. In addition, the camera 100 measures the object to be photographed at multiple points, and distance conversion software for the camera 100, lens, lighting, and number of pixels can be used.

[0044] The camera 100 can stably photograph the sealer 200 as the object to be photographed from the front. As an example, the camera 100 can be stably fixed by being accommodated in the frame portion 103, or can adjust its position while moving stably on the rail.

[0045] In the present disclosure, it is shown that the camera 100 can be accommodated in the frame portion 103 and can move on the first rail 101 or the second rail 102. The first rail 101 extends in a first direction DR1, and the second rail 102 extends in a second direction DR2 perpendicular to the first direction DR1. The second direction DR2 is defined as the direction parallel to the extending direction of the sealer 200.

[0046] The camera 100 can move along the first rail 101 and move along the transportation direction of the secondary battery inside the sealer 200. In addition, the camera 100 can adjust the distance from the sealer 200 as the heat source, and can adjust the focus on the field of view (FOV) while moving along the second rail 102.

[0047] The first rail 101 and the second rail 102 can be, for example, linear motion rails in the form of long rods. However, the types of the first rail 101 and the second rail 102 are not limited to this.

[0048] The sealer 200 includes an upper sealer 210 and a lower sealer 220 facing each other, and is mounted on a heating block 230. The upper sealer 210 and the lower sealer 220 are symmetric to each other, and the distance between the upper sealer 210 and the lower sealer 220 is defined as the gap of the sealer. The sealer 200 can extend along the second direction DR2.

[0049] Meanwhile, the lead wire device 400 can be arranged between the upper sealer 210 and the lower sealer 220. When the secondary battery is mounted on the sealer 200, the electrode leads of the secondary battery can be disposed on the lead wire device 400. The electrode leads of the secondary battery are disposed on the lead wire device 400 and are heated and sealed. Specifically, the electrode leads of the secondary battery are heated by the heater 300 so that the electrode leads of the secondary battery can be heated to a uniform temperature. For example, the heater 300 can heat the electrode leads to the same temperature as the sealer 200, thereby minimizing heat loss caused by the temperature difference between the sealer 200 and the electrode leads during the sealing process. In addition, the heater 300 is located on the front surface of the sealer 200 to minimize heat loss from the electrode leads. In this specification, the front surface of the sealer 200 is defined as the surface of the sealer 200 when viewed from the camera 100.

[0050] The heater 300 can include an upper heater 310 and a lower heater 320 that face each other. The upper heater 310 is disposed on the front surface of the upper sealer 210, and the lower heater 320 is disposed on the front surface of the lower sealer 220. When the sealing device 1000 operates, the upper heater 310 and the lower heater 320 move up and down together with the sealer 200. In this case, the upper heater 310 and the lower heater 320 move up and down to have a negative deviation (i.e., the upper heater 310 and the lower heater 320 overlap each other), so that the heater 300 covers the lead wire device 400 and the sealer 200 within the region AA. The region AA is the region where the lead wire device 400 is disposed and is the region for measuring the gap of the sealer 200 that determines the sealing thickness.

[0051] That is, in the camera 100, the lead wire device 400 and the sealer 200 within the region AA are placed in an invisible region by the heater 300, so that they cannot be directly photographed and measured.

[0052] Therefore, the present disclosure provides a method for sealing a secondary battery that can reliably predict the gap of the sealer 200 placed in the region AA and improve the process efficiency.

[0053] The method for sealing a secondary battery according to the present disclosure is used to seal the electrode leads and the battery case of the secondary battery, and the method includes the following steps:

[0054] Setting a heater on the front surface of the sealer;

[0055] Place the electrode lead between the upper seal and the lower seal of the sealer;

[0056] Heat the electrode lead using the heater;

[0057] Seal the electrode lead and the battery case using the sealer;

[0058] Take an image of the sealer around the heater using a camera disposed in front of the heater to obtain shape information;

[0059] Measure the temperature of the sealer around the heater using a temperature sensor to obtain temperature information;

[0060] Use the shape information, the temperature information, and relevant material information of the sealer to obtain thermal expansion data related to the temperature of the sealer; and

[0061] Measure the temperature of the electrode lead using the temperature sensor, and then use the thermal expansion data to predict the thermal expansion value of the sealer at the electrode lead covered by the heater.

[0062] Next, each step of the method for sealing a secondary battery according to the present disclosure will be specifically described. The same content as above applies to the same configuration as above, and its detailed description will be omitted.

[0063] In a method for sealing an electrode lead and a battery case of a secondary battery, reference will be made to Figure 5 Describe the secondary battery.

[0064] Figure 5 is a perspective view of a secondary battery showing an embodiment.

[0065] In Figure 5 it is shown that the secondary battery of the present disclosure is a pouch-type battery cell as an example, but the type of the secondary battery of the present disclosure is not limited thereto.

[0066] Reference Figure 5, the secondary battery 110 has the following structure: Among them, two electrode leads 111 and 112 protrude from one end 114a and the other end 114b of the monomer main body 113 in opposite directions. The secondary battery 110 can be manufactured in the following manner: with the electrode assembly (not shown) accommodated in the monomer housing 114, the two ends 114a, 114b of the monomer housing 114 and one side surface 114c connecting the two ends are combined. In other words, the secondary battery 110 according to this embodiment has a total of three sealing portions 114sa, 114sb, and 114sc, where the sealing portions 114sa, 114sb, and 114sc have a structure sealed by a method such as heat fusion, and the remaining other side portion can be constituted by a connecting portion 115.

[0067] The connecting portion 115 is a region extending along one edge of the secondary battery 110, and a protruding portion 110p of the secondary battery 110 can be formed at the end of the connecting portion 115. The protruding portion 110p can be formed on at least one of the two ends of the connecting portion 115 and can protrude in a direction perpendicular to the extending direction of the connecting portion 115. The protruding portion 110p can be located between the connecting portion 115 and one of the sealing portions 114sa and 114sb of the two ends 114a and 114b of the monomer housing 114.

[0068] The monomer housing 114 is generally formed into a laminated structure of resin layer / metal thin film layer / resin layer.

[0069] The method for sealing a secondary battery described in the present disclosure is used to form the sealing portions 114sa and 114sb at both ends of the above-mentioned secondary battery 110. Specifically, the method for sealing a secondary battery described in the present disclosure can be applied to seal the two ends 114a and 114b of the battery housing 114 and the electrode leads 111 and 112 to form the sealing portions 114sa and 114sb. However, the application examples of the present disclosure are not limited thereto.

[0070] As an example, the secondary battery described below is understood as the secondary battery 110 described above with reference to Figure 5 description.

[0071] In the method for sealing the electrode leads and the battery housing of a secondary battery, the step of setting a heater on the front surface of the sealer is as follows: setting a heater 300 on the front surface of the sealer 200 to reduce heat loss in the electrode leads. The upper heater 310 of the heater 300 is set on the front surface of the upper sealer 210, and the lower heater 320 of the heater 300 is set on the front surface of the lower sealer 220.

[0072] The step of disposing the electrode lead between the upper sealer and the lower sealer of the sealer is as follows: The electrode lead of the secondary battery is disposed on a lead device 400 that is placed between the upper sealer 210 and the lower sealer 220.

[0073] The secondary battery is disposed on the rear surface of the sealer 200, and the electrode lead of the secondary battery can be disposed on the lead device 400. Meanwhile, the provided secondary battery is transported along a second direction DR2 of the sealer 200.

[0074] The step of heating the electrode lead using the heater is as follows: The heater 300 is used to heat the electrode lead disposed on the lead device 400. The heater 300 heats the electrode lead to a uniform temperature to ensure uniform sealing. In addition, the heater 300 heats the electrode lead to the same temperature as the sealer 200, thereby being able to prevent heat loss due to the temperature difference between the electrode lead and the sealer 200.

[0075] The step of sealing the electrode lead and the battery case using the sealer includes the following steps: Sealing Figure 5 both ends 114a and 114b of the above battery case 114 and the electrode leads 111 and 112 to form the sealing portions 114sa and 114sb. Referring together to Figure 3 and Figure 4 , in the sealing step, the distance between the upper sealer 210 and the lower sealer 220 becomes narrower, and the upper heater 310 and the lower heater 320 come into contact, so that when viewed from the front, the lead device 400 is covered. At this time, the sealer 200 in the area AA where the lead device 400 is disposed is also covered by the heater 300. Meanwhile, the sealing step is performed simultaneously with the above heating step.

[0076] The step of using a camera disposed in front of the heater to photograph the seal around the heater to obtain shape information includes the following steps: using camera 100 to photograph seal 200 in area BB to obtain its shape information. Since camera 100 cannot directly photograph and measure lead device 400 and seal 200 in area AA, camera 100 photographs seal 200 in area BB adjacent to area AA to obtain the shape information on area BB. At this time, area BB may be an area adjacent to area AA in the second direction DR2. For example, area BB may be an area adjacent to both sides of area AA in the second direction DR2. In one embodiment, the shape information is a value obtained by measuring the height of seal 200 within area BB along the length direction. The shape of seal 200 may change according to temperature. Specifically, as seal 200 undergoes thermal deformation, the shape of seal 200 may change according to temperature. Camera 100 is capable of photographing the shape of seal 200 at a specified temperature to provide shape information. The shape information obtained as above is used together with the temperature information and the relevant material information of seal 200 described below to perform thermal expansion simulation and predict the shape of area AA at a specific temperature. Specific details related thereto are described below.

[0077] The step of using a temperature sensor to measure the temperature of the seal around the heater to obtain temperature information is as follows: using temperature sensor 500 to measure the temperature of the sealed area of seal 200. There is a temperature difference between the unsealed area and the sealed area within seal 200. For example, the temperature of the unsealed area in seal 200 may be 180°C to 190°C or less, while the temperature of the sealed area may be 200°C to 250°C or less. In the above step, the temperature of seal 200 in area BB within the sealed area may be measured to obtain temperature information. Specifically, the temperature is measured at two or more points on seal 200 in area BB, and the average value is used as the temperature information. Temperature sensor 500 may be disposed on the upper part of seal 200, as Figures 2 to 4 shown. However, the embodiment is not limited thereto. For example, temperature sensor 500 may be disposed separately from seal 200. Temperature sensor 500 may be a contact-type temperature sensor or a non-contact-type temperature sensor. For example, temperature sensor 500 may include any one of a resistance temperature detector (RTD) sensor, a thermocouple temperature sensor, and an infrared temperature sensor. However, the examples of temperature sensor 500 are not limited thereto.

[0078] The steps of obtaining thermal expansion data related to the temperature of the seal using the shape information, temperature information, and relevant material information of the seal include the following steps: performing a thermal expansion simulation using the above shape information, temperature information, and material information of the seal 200. The temperature information of the seal 200 above is the temperature measured according to the material of the seal 200. For example, the seal 200 may include at least one of BeCu, WC, AlBe, Inconel718, and Ni-Be. Specifically, the seal 200 may include any one of BeCu, WC, AlBe, Inconel718, and Ni-Be. For example, the seal 200 may include BeCu. However, the material of the seal 200 is not limited thereto.

[0079] Similar to the above method, a thermal expansion simulation is performed on the seal of an embodiment by integrating the shape information, material information, and temperature information related to the material. The results are shown in Figure 6 shown.

[0080] Figure 6 is a graph showing the results of the thermal expansion simulation of an embodiment.

[0081] In Figure 6 shown are the results of the thermal expansion simulation for the seals of Examples 1 to 4 and the reference example. The seals of Examples 1 to 4 have the same shape but are made of different materials.

[0082] Example 1 is a seal containing BeCu, Example 2 is a seal containing AlBe, Example 3 is a seal containing Inconel718, Example 4 is a seal containing a super-light alloy (WC, tungsten carbide), and the reference example is a seal containing BeCu. At the same time, the materials correspond to the material information of the above seals.

[0083] In addition, the temperature of the seal in the reference example is 23 °C. The seals of Examples 1 to 4 are heated at an initial temperature of 23 °C and simulated at the following temperatures. Example 1 is 210.6 °C, Example 2 is 210.6 °C, Example 3 is 210.2 °C, and Example 4 is 210.2 °C. In this case, the average natural convection heat transfer coefficient is calculated to be 20 W / m 2 ·°C.

[0084] That is, the seals of Examples 1 to 4 are simulated at approximately the same temperature. At the same time, the temperature corresponds to the above temperature information. Specifically, the temperature is a value obtained by measuring the temperature at two or more points in the sealed area of each seal and averaging these temperatures.

[0085] The sealers of Examples 1 to 4 and the reference example acquire shape information at the above temperatures, and the shape information is displayed on Figure 6 the graph of

[0086] In the graph of Figure 6 , the x-axis represents the length information of the sealer. Specifically, the x-axis is measured in the second direction (DR2, see Figure 2 ) starting from 0 mm as the starting point of the sealing area until 210 mm.

[0087] In the graph of Figure 6 , the y-axis represents the height information of the lower sealer 220. Specifically, the y-axis takes 0 mm as the reference for the height of the end of the lower sealer 220 in the direction perpendicular to the first direction DR1 (see Figure 2 ) and the second direction DR2 (see Figure 2 ).

[0088] When performing simulation using the above shape information, temperature information, and the material information of the sealer, the expected thermal expansion data of the sealer 200 in the area AA can be obtained, and the area AA is the Figure 6 invisible area shown. Based on this, for the sealers with the materials of Examples 1 to 4, even at temperatures different from each temperature information, the thermal expansion values of the sealer 200 in the area AA can be predicted.

[0089] In the above manner, the following steps can be performed: By using the shape information, temperature information, and the relevant material information of the sealer, the thermal expansion data related to the temperature of the sealer can be obtained.

[0090] The steps of measuring the temperature of the electrode lead using the temperature sensor and then predicting the thermal expansion value of the sealer at the electrode lead covered by the heater using the thermal expansion data include the following steps: Using the Figure 6 thermal expansion data of the area AA obtained to predict the thermal expansion value of the sealer 200 at the electrode lead. In order to manage the gap of the sealer 200, it is necessary to measure the thermal expansion value of the sealer 200 at the electrode lead covered by the heater 300 and reflect it in the process. That is, for the sealer 200 in the area AA, the following steps are performed: Predict the thermal expansion value at the electrode lead temperature.

[0091] This step includes the following steps: Measuring the temperature of the electrode lead using the temperature sensor 500, and according to the data obtained from Figure 6The thermal expansion value related to the temperature of the region AA obtained therefrom is used to predict the thermal expansion value of the region AA at the measured temperature of the electrode lead. At this time, the temperature sensor 500 measures the temperature at the central position of the electrode lead, and the central position means the central position of the electrode lead in the second direction DR2.

[0092] The method for sealing a secondary battery according to the present disclosure can predict the thermal expansion value of the seal 200 in the invisible region by performing the above steps.

[0093] Subsequently, the following steps can be further performed: reflecting the predicted thermal expansion value in the process and adjusting the gap of the seal 200 (i.e., the gap between the upper seal 210 and the lower seal 220).

[0094] By using the above method, the present disclosure can reliably predict the gap of the seal in the invisible region on an on-line basis during the sealing process and can manage the sealing thickness which is extremely critical for the quality parameters. Therefore, a method for sealing a secondary battery with high reliability and high efficiency can be provided.

[0095] Although the present invention has been shown and described in detail with reference to the preferred embodiments of the present invention, those skilled in the art will understand that the scope of the present disclosure is not limited thereto, and various modifications and improvements can be made in these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined in the appended claims and their equivalents.

Claims

1. A method for sealing a secondary battery, the method sealing electrode leads and a battery case of the secondary battery, the method comprising the following steps: Setting a heater on a front surface of a sealer; Setting the electrode leads between an upper sealer and a lower sealer of the sealer; Heating the electrode leads by using the heater; Sealing the electrode leads and the battery case by using the sealer; Taking a picture of the sealer around the heater by using a camera disposed in front of the heater to obtain shape information; Measuring a temperature of the sealer around the heater by using a temperature sensor to obtain temperature information; Obtaining thermal expansion data related to a temperature of the sealer by using the shape information, the temperature information, and relevant material information of the sealer; And Measuring a temperature of the electrode leads by using the temperature sensor, and then predicting a thermal expansion value of the sealer at the electrode leads covered by the heater by using the thermal expansion data.

2. The method for sealing a secondary battery according to claim 1, further comprising the following step: adjusting a gap between the upper sealer and the lower sealer according to the predicted thermal expansion value.

3. The method for sealing a secondary battery according to claim 1, wherein, The camera, the heater, and the sealer are arranged in a first direction, and the sealer extends in a second direction perpendicular to the first direction.

4. The method for sealing a secondary battery according to claim 3, wherein, When predicting the thermal expansion value, the temperature sensor measures a temperature at a central position of the electrode leads, and the central position is a central position of the electrode leads in the second direction.

5. The method for sealing a secondary battery according to claim 3, wherein, The camera is disposed in front of the sealer.

6. The method for sealing a secondary battery according to claim 1, wherein, The shape information is obtained by measuring a height of the sealer along a length direction of the sealer.

7. The method for sealing a secondary battery according to claim 1, wherein, The temperature sensor includes any one of a resistance temperature detector (RTD) sensor, a thermocouple temperature sensor, and an infrared temperature sensor.

8. The method for sealing a secondary battery according to claim 1, wherein, The step of heating the electrode leads and the step of sealing the electrode leads are performed simultaneously.

9. The method for sealing a secondary battery according to claim 1, wherein, The sealer includes at least one of BeCu, WC, AlBe, Inconel718, and Ni-Be.

10. The method for sealing a secondary battery according to claim 1, wherein, The secondary battery includes an electrode assembly accommodated in the battery case, and the electrode leads protrude from the electrode assembly at both ends of the battery case.

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