Sealing device

Abstract

The present invention relates to a sealing device including an upper sealing block and a lower sealing block, a sealing gap measuring unit coupled to the upper sealing block, and a reference block coupled to the lower sealing block opposite the sealing gap measuring unit, the sealing gap measuring unit including: a probe housing coupled to the upper sealing block; a probe having both ends protruding from an upper portion and a lower portion of the probe housing, respectively, and penetratingly installed within the probe housing so as to be movable relative to the probe housing; and a sensing unit for sensing a height or a change in height of the probe protruding from the upper portion of the probe housing.

Description

[Technical Field]

[0001] The present invention relates to a sealing apparatus for sealing pouch-type battery cells.

[0002] More particularly, the present invention relates to a sealing apparatus capable of real-time measuring, even during sealing of a battery cell in a mass production process, a sealing gap that is a gap between an upper sealing block and a lower sealing block and is directly related to the sealing quality of the battery cell.

[0003] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0098002 filed on August 5, 2022, and all contents disclosed in the document of the said Korean patent application are incorporated as a part of the present specification. [Background Art]

[0004] Along with the increasing technological development and demand in the fields of mobile devices, automobiles and energy storage devices, the demand for rechargeable secondary batteries as an energy source is increasing rapidly. Among such secondary batteries, lithium secondary batteries with high energy density and discharge voltage are most widely used.

[0005] Particularly, when high output and large capacity are required such as for automobiles and energy storage devices, medium and large-sized battery packs in which a large number of battery cells are electrically connected are used. Medium and large-sized battery packs can be stacked with a high degree of integration, and pouch-type secondary batteries, which are light weight relative to their capacity, are mainly used. The above-mentioned pouch-type secondary battery is a secondary battery having a structure in which an electrode assembly is accommodated in a pouch-type case having a laminated structure.

[0006] Figure 1 is a schematic diagram showing the structure of a general pouch-type battery cell, Figure 2 is a schematic diagram showing a part for measuring the sealing thickness in a pouch-type battery cell, and Figure 3 is a flow chart showing a conventional process of adjusting the sealing thickness of a battery cell.

[0007] As shown in Figure 1, the pouch-type battery case 20 includes an upper case 20A and a lower case 20B. The upper case 20A and the lower case 20B are each provided with electrode assembly housing spaces 21A and 21B, respectively. The electrode assembly 10 is housed in these electrode assembly housing spaces, and after the electrolyte is poured into the housing spaces, the upper case 20A and the lower case 20B are closed to seal the edges of the battery case 20. In other words, the edges of the battery case are the parts to be sealed.

[0008] The electrode assembly 10 is made up of multiple stacked positive electrodes, separator membranes, and negative electrodes, with electrode leads 11 and 12 leading out from both ends or one end.

[0009] As shown in Figure 2, the electrode assembly 10 is housed in the pouch-type battery case 20, and the edges of the case are sealed. The pouch-type battery case 20 forms the overall appearance of the secondary battery and is made of a ductile material. The pouch-type battery case 20 includes a gas barrier layer, a surface protection layer, and a sealant layer. The gas barrier layer is for blocking the entry and exit of gas and contains metal; for example, aluminum foil may be used. The surface protection layer is located on the outermost layer of the battery case 20, and a polymer such as nylon resin or PET, which has abrasion resistance and heat resistance, may be used. The sealant layer is located on the innermost layer, and a polymer such as polypropylene (PP) may be used. The pouch-type battery case 20 is manufactured by processing a film in which the above layers are laminated into a pouch. Specifically, the upper case 20A and the lower case 20B are brought into contact with each other, and when the edges are heat-pressed, the sealant layers are bonded together, thereby sealing the battery case 20.

[0010] However, conventionally, it was not possible to measure the sealing gap (the distance between the upper and lower sealing blocks that seal the edge of the battery case) or changes in the sealing gap in real time while the sealing process was actually underway. Because the upper and lower sealing blocks are sealed at a high temperature heated by a heating block, it was difficult to place a sensor for measuring the sealing gap near that high-temperature sealing area. This was because there was a high possibility that temperature-sensitive sensors would have their measurement sensitivity altered or be damaged by the high temperature. Furthermore, because the above sealing gap changes in real time during sealing, it was extremely difficult to place a sensor near the sealing area and directly measure the gap in response to the changes in the sealing gap.

[0011] Therefore, conventionally, in order to confirm the sealing thickness of the sealing target portion of the battery cell 1, a sample was selected as shown in Figures 2 and 3, and a sampling inspection was performed in which the sealing thickness of the sample was directly measured at multiple locations P. In other words, it was difficult to survey the sealing thickness of all battery cells.

[0012] In this case, the production line had to be stopped for sampling inspection, which reduced actual production time and lowered productivity. Furthermore, productivity was further reduced because it was necessary to adjust the sealing gap through sampling inspection, and then re-introduce the sample to reconfirm the sealing thickness to confirm whether the sealing quality was good with the adjusted sealing gap.

[0013] Thus, conventionally, the sealing gap, which determines the sealing thickness, was not measured in real time. As a result, the detection of sealing defects due to the sealing gap or changes in that gap was delayed, and defective battery cells were sometimes shipped as is. Therefore, there was a risk to quality control. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] Korean Published Patent Publication No. 10-2021-0085975 [Overview of the project] [Problems that the invention aims to solve]

[0015] The present invention aims to solve the above-mentioned problems and to provide a sealing device that can measure the sealing gap between upper and lower sealing blocks in real time even during the sealing of a pouch-type battery case. [Means for solving the problem]

[0016] A sealing device according to one embodiment of the present invention for solving the above problems includes an upper sealing block and a lower sealing block arranged vertically with a battery cell in between, which move relative to each other to seal the portion of the battery cell to be sealed; a sealing gap measuring unit coupled to the upper sealing block; and a reference block coupled to the lower sealing block opposite the sealing gap measuring unit. The sealing gap measuring unit includes a probe housing coupled to the upper sealing block; a probe whose ends protrude from the upper and lower parts of the probe housing, respectively, and which is installed penetrating the probe housing so as to be movable relative to the probe housing; and a sensing unit that senses the height or height change of the probe protruding from the upper part of the probe housing. When the upper sealing block and the lower sealing block pressurize and seal the battery cell while moving relative to each other, the lower end of the probe rises due to pressure from the reference block, and the sealing gap between the upper sealing block and the lower sealing block can be measured based on the amount of height rise of the probe sensed by the sensing unit.

[0017] The upper sealing block and the lower sealing block described above may each include a heating block for heating the part to be sealed and a sealing part coupled to the lower part of the heating block.

[0018] The above-mentioned sealing gap measuring section may be installed on both sides of the upper sealing block with the sealing portion of the upper sealing block in between, and the above-mentioned reference block may be installed on both sides of the lower sealing block with the sealing portion of the lower sealing block in between.

[0019] The sensing unit described above may be a non-contact displacement sensor that measures the height change of the probe, or a non-contact position sensing sensor that senses the upper position of the probe.

[0020] The sensing unit can measure the height increase of the probe at the end of a predetermined set sealing time for each battery cell, and measure the sealing gap based on the height increase of the probe at the end of that time.

[0021] The probe housing may include a through hole for housing the probe, and the probe may include a main body having a first end and a second end protruding from the upper and lower parts of the probe housing, respectively, and a probe diameter expansion portion having a larger diameter than the main body, which is housed in the through hole of the probe housing between the first end and the second end.

[0022] The probe further comprises an elastic member wound around the main body, and the probe can be moved downward relative to the probe housing by the elastic force of the elastic member and upward relative to the probe housing by the pressure applied by the reference block.

[0023] The sealing device described above further includes: a first guide member coupled to an upper inner circumferential surface of the through-hole and including a first guide hole into which the probe is inserted; and a second guide member coupled to a lower inner circumferential surface of the through-hole and including a second guide hole into which the probe is inserted, wherein the elastic member is wound around the probe section between a lower end of the first guide member and an enlarged diameter portion of the probe, and can be positioned between an outer circumferential surface of the probe and an inner circumferential surface of the through-hole.

[0024] The first guide member includes: a guide main body portion coupled to the upper inner circumferential surface of the through-hole; and a guide enlarged diameter portion fixedly coupled to an upper surface of the probe housing at an upper part of the guide main body portion, wherein the guide main body portion and the guide enlarged diameter portion can be provided with the first guide hole into which the probe is inserted.

[0025] The elastic member has an elastic force set to bias downward, the probe moves downward when the enlarged diameter portion of the probe is pressed downward by the elastic force of the elastic member, and the enlarged diameter portion is blocked by an upper end surface of the second guide member, so that further downward movement of the probe can be restricted.

[0026] When the lower end portion of the probe is pressed against the reference block, and the enlarged diameter portion of the probe and the probe move upward against the elastic force of the elastic member, the elastic member can be compressed between the lower end of the first guide member and the enlarged diameter portion of the probe.

[0027] Before measuring the sealing gap, an ascending position of the probe corresponding to a sealing gap that achieves favorable sealing is obtained by relatively moving an upper sealing block and a lower sealing block, the obtained ascending position is set as a zero point position, and thereafter, when a plurality of battery cells are actually sealed by relatively moving the upper and lower sealing blocks, the height ascending amount of the probe or a change in the ascending amount is compared with the zero point position, so that the sealing gap or a change in the sealing gap during actual battery cell sealing can be measured in real time with reference to the zero point position.

[0028] The above-mentioned zero point position may be the raised position of the probe when the stoppers provided on the upper and lower sealing blocks, respectively, come into contact.

[0029] The system may further include a determination unit that measures the sealing gap at the time of detection by comparing the height increase of the detected probe with the corresponding sealing gap data, and determines whether or not there is a sealing defect by comparing the measured sealing gap with the sealing gap data corresponding to a sealing defect.

[0030] The sealing gap measuring section can be connected to the upper sealing block with a cover member interposed between the heating block and the sealing gap measuring section of the upper sealing block, which insulates against the heat of the heating block. [Effects of the Invention]

[0031] According to the present invention, the sealing gap between the upper and lower sealing blocks can be measured in real time even during the sealing of the battery case, which has the advantage of being easily applicable to the mass production process of actual battery cells.

[0032] Furthermore, by measuring the sealing gap in real time, it is possible to quickly detect battery cells with poor sealing quality, making quality control of sealing thickness extremely easy.

[0033] Furthermore, since the measured sealing gap can be digitized and linked to the sealing quality, it is easy to manage the history of sealing quality, and quality control can be easily managed digitized. [Brief explanation of the drawing]

[0034] [Figure 1] This is a schematic diagram showing the structure of a typical pouch-type battery cell. [Figure 2]This is a schematic diagram showing the area for measuring the sealing thickness in a pouch-type battery cell. [Figure 3] This is a flowchart illustrating the process for adjusting the sealing thickness of conventional battery cells. [Figure 4] This is a schematic diagram showing the state of the sealing device of the present invention before the start of sealing. [Figure 5] This is a schematic diagram showing the state of the sealing device of the present invention at the start of sealing and during sealing. [Figure 6] This is a schematic diagram showing the state of the sealing device of the present invention at the end of the sealing process. [Figure 7] This is a cross-sectional view showing the positional relationship between the sealing gap measurement section and the reference block before sealing begins. [Figure 8] This is a cross-sectional view showing the positional relationship between the sealing gap measurement section and the reference block at the start and during sealing. [Figure 9] This is a cross-sectional view showing the positional relationship between the sealing gap measurement section and the reference block at the end of the sealing process. [Figure 10] This is a schematic diagram showing the main parts of a sealing device according to another embodiment of the present invention. [Modes for carrying out the invention]

[0035] The present invention will become more apparent by describing preferred embodiments in detail with reference to the accompanying drawings. The embodiments described herein are illustrative to aid in understanding the invention, and the present invention may be carried out in various modified ways different from the embodiments described herein. Furthermore, the accompanying drawings provided to aid in understanding the invention are not drawn to actual scale, and the dimensions of some components may be exaggerated.

[0036] A sealing device according to one embodiment of the present invention includes an upper sealing block and a lower sealing block arranged vertically with a battery cell in between, which move relative to each other to seal the portion of the battery cell to be sealed; a sealing gap measuring unit coupled to the upper sealing block; and a reference block coupled to the lower sealing block opposite the sealing gap measuring unit. The sealing gap measuring unit includes a probe housing coupled to the upper sealing block; a probe whose ends protrude from the upper and lower parts of the probe housing, respectively, and which is installed penetrating the probe housing so as to be movable relative to the probe housing; and a sensing unit that senses the height or height change of the probe protruding from the upper part of the probe housing. When the upper sealing block and the lower sealing block pressurize and seal the battery cell while moving relative to each other, the lower end of the probe is pressed against the reference block and rises, and the sealing gap between the upper sealing block and the lower sealing block can be measured based on the amount of height rise of the probe sensed by the sensing unit.

[0037] The present invention will be described in detail below.

[0038] (First Embodiment) Figures 4 to 6 are schematic diagrams showing the state of a sealing device according to one embodiment of the present invention before sealing begins, during sealing, and at the end of sealing, respectively.

[0039] Figures 7 to 9 are cross-sectional views showing the positional relationship between the sealing gap measurement section and the reference block before sealing begins, during sealing, and after sealing is complete.

[0040] The sealing device 1000 of the present invention includes an upper sealing block 100 and a lower sealing block 200 arranged vertically with a battery cell in between, which move relative to each other to seal the portion of the battery cell to be sealed; a sealing gap measuring unit 300 coupled to the upper sealing block 100; and a reference block 400 coupled to the lower sealing block 200 opposite the sealing gap measuring unit 300.

[0041] The upper sealing block 100 and the lower sealing block 200 described above are the parts that heat and pressurize the sealing target portion of the pouch-type battery case to directly seal it. For this purpose, the upper sealing block 100 and the lower sealing block 200 may each include heating blocks 120 and 220 for heating the sealing target portion, and sealing portions 130 and 230 coupled to the lower part of the heating blocks 120 and 220. However, the coupling relationship between the heating blocks 120 and 220 and the sealing portions 130 and 230 is not limited to this, and for example, a heating coil may be included in the sealing portions 130 and 230, and the heating blocks 120 and 220 and the sealing portions 130 and 230 may be integrated into one form. The battery cell is positioned between the sealing portions 130 and 230 of the upper sealing block 100 and the lower sealing block 200, and sealing of the battery cell is performed by the relative movement of the upper sealing block 100 and the lower sealing block 200, that is, by the movement of the upper sealing block 100 and the lower sealing block 200 toward each other.

[0042] Relative movement includes both cases where one of the upper ceiling block 100 and the lower ceiling block 200 (for example, the lower ceiling block) is stationary while the other block (for example, the upper ceiling block 100) moves, or where the upper ceiling block 100 and the lower ceiling block 200 move in a manner that allows them to access and separate from each other simultaneously.

[0043] The embodiment shown in Figure 4 assumes a case where the upper sealing block 100 and the lower sealing block 200 move simultaneously. For this purpose, the upper sealing block 100 and the lower sealing block 200 are equipped with drive units 110 and 210, respectively. Examples of drive units 110 and 210 include a pressure source and a cylinder movement mechanism of a pneumatic or hydraulic cylinder connected to the pressure source. Alternatively, a linear movement mechanism such as a servo motor (drive source) and a ball screw mechanism connected thereto can also be used as a drive unit. Since such drive units or drive mechanisms are publicly known, a detailed explanation will be omitted.

[0044] Figure 4 shows the state before the sealing ring begins, with the upper sealing block 100 and the lower sealing block 200 separated.

[0045] As shown in Figure 5, sealing begins when the upper sealing block 100 and the lower sealing block 200 are brought close together and positioned at a predetermined distance apart, due to the drive units 110 and 210 provided in the upper sealing block 100 and the lower sealing block 200. More precisely, sealing of the battery cells begins when the sealing portion 130 of the upper sealing block 100 and the sealing portion 230 of the lower sealing block 200 are positioned at a predetermined distance G1. This predetermined distance G1 is called the sealing gap. However, the sealing gap is not a fixed value, but gradually decreases as the upper sealing block 100 and the lower sealing block 200 move relative to each other from the start to the end of sealing.

[0046] As illustrated in Figure 6, the sealing gap G2 is minimized at the end of the set sealing time, and the thickness of the area being sealed at this time becomes the sealing thickness. In other words, the sealing gap and the sealing thickness are proportional, and therefore the sealing gap is closely related to the uniformity of the sealing thickness, i.e., the uniformity of the sealing quality.

[0047] The upper sealing block 100 and the lower sealing block 200 are each equipped with stoppers (121, 221) protruding from both sides. The upper sealing block 100 and the lower sealing block 200 move relative to each other even during sealing of the area to be sealed, and relative movement stops when the stoppers (121, 221) of the upper and lower sealing blocks (100, 200) come into contact. Because the protruding height of the stoppers (121, 221) provided on each sealing block is higher than the surface of the sealing portion (130, 230) of the upper and lower sealing blocks (100, 200), a gap is formed between the sealing portion 130 of the upper sealing block 100 and the sealing portion 230 of the lower sealing block 200 even when the stoppers (121, 221) come into contact. That is, this gap becomes the smallest sealing gap G2, and the thickness of the area to be sealed within this sealing gap becomes the smallest sealing thickness.

[0048] Typically, the sealing gap G1, which is a predetermined interval at which sealing begins, is determined by the design specifications for manufacturing the target product. For example, when the upper and lower sealing blocks (100, 200) are moved by a servo motor, the servo motor's servo value is set so that the sealing portion 130 of the upper sealing block 100 and the sealing portion 230 of the lower sealing block 200 are positioned at a predetermined distance from each other. Therefore, when the servo values ​​of the servo motors, which are the drive units 110 and 210 of the upper sealing block 100 and the lower sealing block 200, reach the set value, the control unit of the drive unit recognizes that the distance between the upper sealing block 100 and the lower sealing block 200 has reached the predetermined distance, and sealing begins. After sealing has started and the set sealing time has elapsed, the control unit issues a movement instruction to each drive unit so that the upper sealing block 100 and the lower sealing block 200 move away from each other. For reference, the heating blocks 120 and 220 provided in the upper sealing block 100 and lower sealing block 200 are already heated before sealing begins, i.e., in the state shown in Figure 4. Therefore, when the sealing start position is reached as shown in Figure 5, sealing of the target portion of the battery cell is performed at the set temperature and pressure.

[0049] As described above, the sealing gap changes during sealing because the upper sealing block 100 and the lower sealing block 200 move relative to each other and are pressurized. Furthermore, the sealing gap at the end of sealing is not necessarily the smallest sealing gap when the stoppers 121 and 221 are in contact. As shown in Figure 6, it is ideal for the stoppers of the upper sealing block 100 and the lower sealing block 200 to be in contact to achieve the smallest sealing thickness, but in reality, the sealing gap may not be the smallest at the end of sealing due to the melting manner of the sealant on the inner surface of the case of the part to be sealed, the applied pressure, the heating temperature, etc. What is important is that the sealing gap at the end of sealing must be controlled to a range that does not result in a sealing defect in the part to be sealed. For example, if the sealing gap at the end of sealing is large and the sealing thickness is excessively large, it will result in a sealing defect.

[0050] However, as shown in Figure 3, conventional methods have made it extremely difficult to measure the fluctuating sealing gap in real time during the mass production process in which multiple battery cells 1 are continuously sealed. Therefore, the only option was to sample the battery cells, directly measure the sealing thickness of only the sampled samples using a micrometer or similar instrument, and then readjust the sealing gap to the interval that would result from a good sealing thickness—a complex process that had to be followed.

[0051] The present invention aims to solve these problems and includes a sealing gap measuring unit 300 coupled to the upper sealing block 100 for measuring the sealing gap in real time, and a reference block 400 coupled to the lower sealing block 200 opposite the sealing gap measuring unit 300.

[0052] Referring to Figures 4 to 6, the sealing gap measuring units 300 are installed on both sides of the upper sealing block 100, with the sealing portion 130 of the upper sealing block 100 in between. Similarly, the reference blocks 400 are installed on both sides of the lower sealing block 200, with the sealing portion 230 of the lower sealing block 200 in between. It is also possible to measure the sealing gap measuring units 300 and reference blocks 400 on either one side of the sealing block. However, since it is preferable to evaluate the flatness of the sealing surface or the sealing thickness of the sealing target area over the entire sealing target area, it is preferable to install the sealing gap measuring units 300 and reference blocks 400 symmetrically on both sides of the upper sealing block 100 and the lower sealing block 200, as shown in Figures 4 to 6. In this case, by measuring and comparing the sealing gaps on both the left and right sides in real time, the sealing quality of the sealing target area of ​​the battery cell can be comprehensively grasped.

[0053] The sealing gap measuring section 300 is fixedly connected to both sides of the upper sealing block 100. Therefore, the sealing gap measuring section 300 moves together with the upper sealing block 100 when it moves. Referring to Figure 4, the sealing gap measuring section 300 is connected to the side of the upper sealing block 100 via mounting bracket B. The reference block 400 is fixedly connected to the lower sealing block 200 and moves together with the lower sealing block 200 when it moves. The reference block 400 is installed on the lower sealing block 200 opposite the sealing gap measuring section 300. Therefore, when the upper sealing block 100 and the lower sealing block 200 move closer together, the sealing gap measuring section 300 and the reference block 400 also move closer together.

[0054] When sealing begins, as shown in Figure 5, the probe 320 installed in the sealing gap measuring section 300 will come into contact with the upper surface of the reference block 400.

[0055] The above-mentioned sealing gap measuring unit 300 includes a probe housing 310 coupled to the upper sealing block 100, a probe 320 installed inside the probe housing 310, and a sensing unit 330 that senses the height or height change of the probe 320.

[0056] The probe housing 310 is the location where the probe 320 is housed and installed, and is fixedly connected to the upper sealing block 100. Therefore, when the upper sealing block 100 is moved, the probe housing 310 is also moved. The probe housing 310 may be rectangular prism-shaped as shown in the figure. However, it is not limited to this and may be cylindrical or other shapes.

[0057] The probe 320 has both ends protruding from the upper and lower parts of the probe housing 310, respectively, and is installed penetrating the probe housing 310 so as to be movable relative to the probe housing 310. In other words, the probe is also installed inside the probe housing 310 and moves along with the movement of the probe housing 310. Therefore, when the upper moving block moves relative to the lower moving block and approaches it, the probe 320 also moves down and approaches the reference block 400 of the lower moving block.

[0058] As shown in Figure 5, when the upper sealing block 100 and the lower sealing block 200 are positioned at a predetermined sealing gap where sealing of the battery cells begins, the probe 320 also comes into contact with the upper surface of the reference block 400 and is pressurized by its upper surface. In this case, from the start to the end of sealing, as the upper sealing block 100 and the lower sealing block 200 move relative to each other to pressurize and seal the battery cells, the lower end of the probe is also continuously pressurized against the reference block 400. As a result, the upper part of the measuring probe moves relative to the probe housing 310 and protrudes (rises) further above the probe housing 310. Based on the amount of height rise of this protruding probe 320, the sealing gap between the upper sealing block 100 and the lower sealing block 200 can be measured.

[0059] A sensing unit 330 is installed on the upper part of the probe housing 310 to sense the height or height change of the probe 320 that protrudes from the upper part of the probe housing 310. The sensing unit 330 may be a non-contact displacement sensor that measures the height change of the probe 320, or a non-contact position sensing sensor that senses the upper position of the probe 320. For example, the sensing unit 330 may be an optical sensor equipped with a light emitter and a light receiver. When the probe 320 is positioned between the light emitter and the light receiver, and multiple light emitters are arranged on both sides of the probe 320 along the height direction of the probe 320, the height of the probe 320 (i.e., the length protruding from the probe housing 310) and the height change can be measured. That is, the height or height change of the probe 320 can be sensed by the light receiver receiving the light that is reflected by the probe after being transmitted from the light emitter. In this case, the optical sensor is a non-contact displacement sensor. Alternatively, a magnet can be placed on the upper end of the probe 320 or an adjacent portion, and the upper position of the probe 320 or a change in its position can be detected by sensing the position of this magnet. As such a position sensing sensor, for example, a Hall sensor using the Hall effect can be used. The sensor as the sensing unit 330 that senses the height or height change of the probe 320 is not limited to the above, but other suitable sensors can be applied as long as they can accurately measure the height change or rise of the probe 320 in accordance with the height of the probe 320.

[0060] The probe 320 is installed so that both ends protrude from the upper and lower parts of the probe housing 310, respectively. Only when the lower end of the probe 320 protrudes from the lower part of the probe housing 310 can it contact and pressurize the reference block 400 at the start of sealing. Also, only when the upper end of the probe 320 protrudes from the upper part of the probe housing 310 at the start of sealing can the change (increase) in its protrusion height from the initial protrusion height to the end of sealing be measured.

[0061] Furthermore, the probe 320 is installed penetrating the probe housing 310 so as to be movable relative to the probe housing 310. If the probe 320 is fixedly coupled to the probe housing 310, it cannot rise even when pressurized by the reference block 400. Therefore, the probe 320 needs to be installed so as to be movable relative to the probe housing 310. That is, when the probe housing 310 descends, the lower end of the probe 320 is pressurized by the reference block 400 and installed so as to be displaced upward relative to the probe housing 310.

[0062] Specifically, the probe 320 is installed so as to be able to move up and down while being restricted from the probe housing 310. For this purpose, a predetermined restricting member is installed between the probe housing 310 and the probe 320. The restricting member allows the probe 320 to move up and down within a limited range within the probe housing 310.

[0063] Figures 7 to 9 disclose an example of a probe vertical movement mechanism or regulating mechanism.

[0064] As shown in Figure 7, the probe housing 310 is provided with a through hole 311 for housing the probe 320. The probe 320 may comprise a main body portion 321 having a first end 321a and a second end 321b protruding from the upper and lower parts of the probe housing 310, respectively, and a probe diameter expansion portion 322 having a larger diameter than the main body portion 321, which is housed in the through hole 311 of the probe housing 310 between the first end 321a and the second end 321b. The upper and lower surfaces of the diameter expansion portion 322 may serve as restricting surfaces that restrict the vertical movement of the probe 320, as will be described later.

[0065] To achieve restricted vertical movement of the probe 320 within the probe housing 310, an elastic member 340 is wound around the main body 321 of the probe 320 as a first restricting member. As an example, the probe 320 may be moved downward relative to the probe housing 310 by the elastic force of the elastic member 340, and moved upward relative to the probe housing 310 by the pressure applied by the reference block 400.

[0066] A first guide member 350 and a second guide member 360 are provided in the probe housing 310 as second and third restricting members for limiting the extension and contraction of the elastic member 340 and the movement of the probe 320. In other words, the elastic member 340, the first guide member 350, and the second guide member 360 become the first, second, and third restricting members for the restricted vertical movement of the probe.

[0067] As shown in Figure 7, the first guide member 350 has a guide body portion 351 that is coupled to the upper inner circumferential surface of the through hole 311, and a guide diameter expansion portion 352 that is fixedly coupled to the upper surface of the probe housing 310 at the upper part of the guide body portion 351. Furthermore, the guide body portion 351 and the guide diameter expansion portion 352 are provided with a first guide hole 351a into which the probe 320 is inserted. Therefore, the first guide member 350 simultaneously achieves the function of guiding the movement of the probe 320 within the first guide hole 351a while restricting its upward movement.

[0068] On the other hand, a second guide member 360 is connected to the lower inner circumferential surface of the through hole 311. The second guide member 360 has a second guide hole 361 into which the probe 320 is inserted, and simultaneously achieves the function of guiding the movement of the probe 320 within the second guide hole 361 while restricting its downward movement.

[0069] Preferably, at least one of the first guide member 350 and the second guide member 360 may be composed of a ball bushing. The ball bushing has a ball bearing installed in the guide hole of the guide member. When the guide member is composed of such a ball bushing, the probe 320 can move smoothly while minimizing friction as it repeatedly moves up and down within the guide hole. Since the specific form of the ball bushing is publicly known, a detailed description thereof will be omitted. In this embodiment, the second guide member 360 consists of a ball bushing mechanism, allowing the probe 320 to move stably within the probe housing 310.

[0070] The elastic member 340 is wound around the probe portion between the lower end of the first guide member 350 and the probe diameter expansion portion 322, and is positioned between the outer circumferential surface of the probe 320 and the inner circumferential surface of the through hole 311. As shown in Figures 7 to 9, the dimensions or diameter of the elastic member 340 can be set such that the upper end of the elastic member 340 contacts the lower end surface of the guide body portion 351 of the first guide member 350, and the lower end of the elastic member 340 contacts the upper surface of the probe diameter expansion portion 322 of the probe 320. Therefore, when the probe 320 rises, the upper surface of the probe diameter expansion portion 322 becomes a pressurizing surface that pressurizes the elastic member 340, and when the probe 320 descends, the upper surface of the probe diameter expansion portion 322 becomes a pressure-receiving surface that receives the pressure of the elastic member 340. If necessary, the upper end of the elastic member 340 can be fixed to the lower end of the first guide member 350, or the lower end of the elastic member 340 can be fixed to the upper surface of the probe diameter expansion portion 322. This allows the elastic member 340 to stably expand and contract between the probe diameter expansion portion 322 and the first guide member 350.

[0071] The diameter of the probe diameter enlargement portion 322 is set such that the lower surface of the probe diameter enlargement portion 322 contacts and is restricted by the upper end surface of the second guide member 360.

[0072] The operation process of the probe 320 of the sealing gap measuring unit 300 and the reference block 400 when sealing of the battery cell is performed by the relative movement of the upper sealing block 100 and the lower sealing block 200 described above will be explained.

[0073] First, as shown in Figure 4, in the state before sealing begins, when the upper sealing block 100 and the lower sealing block 200 are separated, as shown in Figure 7, the lower end of the probe 320 of the sealing gap measuring unit 300 is separated from the reference block 400 which is coupled to the lower sealing block 200.

[0074] In this state, the elastic force of the elastic member 340 is set so that it is biased downward. Therefore, the upper surface of the probe's enlarged diameter portion 322 is pressed downward by the elastic force of the elastic member 340. As a result, the probe 320 is moved downward, and the lower end of the probe protrudes from the bottom of the probe housing 310. This state is the state of the upper sealing block 100 and the lower sealing block 200 before sealing.

[0075] The probe 320 is moved downward by the force exerted by the elastic member 340, but the probe's enlarged diameter portion 322 is blocked by the upper end surface of the second guide member 360, limiting further downward movement of the probe 320. In Figure 7, the probe's enlarged diameter portion 322 is in contact with the upper end surface of the second guide member 360. However, due to the length of the probe 320, the elastic force of the elastic member 340, and its extension stroke, the probe's enlarged diameter portion 322 may remain in contact with the upper end surface of the second guide member 360, and this state may be the state before sealing.

[0076] In this state, the upper part of the probe 320 protrudes from the probe housing 310. The sensing unit 330 measures the length or height of the protrusion of the part of the probe 320 and records it as the probe height before sealing.

[0077] As the upper sealing block 100 and the lower sealing block 200 move relative to each other, and the sealing gap becomes a predetermined distance G1 as shown in Figure 5, sealing of the area to be sealed begins. In this state, as shown in Figure 8, the lower end of the probe 320 coupled to the upper sealing block 100 contacts the reference block 400 coupled to the lower sealing block 200. As sealing is performed, the probe 320 is pressed against the reference block 400 and moves upward through the through hole 311 of the probe housing 310, the first guide hole 351a of the first guide member 350, and the second guide hole 361 of the second guide member 360. At this time, the expanded diameter portion 322 of the probe moves upward against the elastic force of the elastic member 340. As a result, the protruding height of the probe 320 gradually increases. That is, the amount of upward movement of the probe gradually increases. Since the upper end of the elastic member 340 is restricted by the lower end surface of the first guide member 350, as the probe diameter expansion portion 322 rises, the elastic member 340 is compressed between the lower end of the first guide member 350 and the probe diameter expansion portion 322. Referring to Figure 8, it can be seen that the probe 320 rises and its protruding height becomes higher. That is, the probe 320 rises by a distance Y from the initial protruding height X to a protruding height Z. The sensing unit 330 can measure the changed protruding height Z, or the rise amount Y, which is the amount of change in protruding height. Z or Y is inversely proportional to the sealing gap, which is the distance between the sealing portions of the upper sealing block 100 and the lower sealing block 200. Therefore, by measuring the height rise of the probe 320, the sensing unit 330 can measure the sealing gap. Since the sealing gap is proportional to the sealing thickness, the sealing gap or sealing thickness can be quantitatively measured by measuring the height rise.

[0078] For the sake of explanation, the protrusion height of the probe 320 at the point when its lower end begins to contact the reference block 400 was defined as the protrusion height at the start of sealing. However, depending on the sealing gap, the protrusion height at the start of sealing can also be defined as the protrusion height at the point when the probe 320 has risen by a certain length after contacting and being pressurized by the reference block 400. In this case, the sealing gap can be measured by measuring the additional rise from the initial protrusion height as sealing progresses.

[0079] On the other hand, when the set sealing time is completed from the start of sealing, the upper sealing block 100 and the lower sealing block 200 are in their closest proximity. In this state, the probe 320 is in its maximum upward position, and the upward movement Y is also at its maximum. The distance between the sealing portions of the upper sealing block 100 and the lower sealing block 200 at this maximum upward movement is the minimum sealing gap G2. Since this minimum sealing gap indicates the sealing thickness of the area to be sealed, it is necessary to accurately measure this sealing gap. In the present invention, the minimum sealing gap can be measured by measuring the maximum height Z or maximum upward movement Y of the probe 320 at the maximum upward movement.

[0080] The sealing thickness of the battery cell is determined to be good when it corresponds to the minimum sealing gap set by the maximum height or maximum rise. If it falls below the minimum sealing gap set by the maximum height or maximum rise, the battery cell may be determined to have poor sealing.

[0081] However, in practice, it is difficult to precisely control the above-mentioned sealing gap with pinpoint accuracy. Therefore, it is preferable to perform range control so that the sealing gap is judged as acceptable when the protruding height of the probe 320 falls within a predetermined upper or lower limit range set from the maximum height or maximum rise amount. In other words, the quality of the sealing gap or sealing thickness can be judged as acceptable if it falls within a predetermined upper or lower limit range from the target maximum rise amount (corresponding to the minimum sealing gap), and unacceptable if it falls outside that range.

[0082] As shown in Figure 6, the sealing device 1000 or the control units of the drive units 110 and 210 may move the upper sealing block 100 and the lower sealing block 200 closer together until the stopper 121 of the upper sealing block 100 and the stopper 221 of the lower sealing block 200 come into contact. That is, the control unit may control the drive units of the upper sealing block 100 and the lower sealing block 200 so that the smallest sealing gap is achieved when the stoppers come into contact. Theoretically, the protrusion height of the probe 320 is maximized in this case.

[0083] However, even when the drive unit moves the upper sealing block 100 and the lower sealing block 200 according to the set servo value, the stopper may not actually make contact. This is because, depending on the melting manner of the sealant on the inner surface of the battery cell case, the applied pressure, the heating temperature, etc., the sealing gap may not be minimized even at the end of sealing. Therefore, in such cases, even though the sealing is not actually performed with a sealing thickness corresponding to the minimum sealing gap, the sealing thickness may be judged as acceptable, and a poorly sealed battery cell may be released to the outside. In this case, it is necessary to adjust the minimum sealing gap. Conventionally, because the sealing gap could not be measured in real time, there were cases where a battery cell was judged as acceptable even when it was not sealed with the minimum sealing gap mentioned above.

[0084] According to the present invention, the change in the sealing gap can be measured in real time according to the amount the probe 320 rises, thus preventing the above-mentioned problems. Specifically, the raised position of the probe 320 corresponding to the sealing gap that results in good sealing due to the relative movement of the upper sealing block 100 and the lower sealing block 200 can be determined in advance, and this raised position can be set as the zero point position. When setting the zero point position, it is not necessarily required to install a battery cell between the upper and lower sealing blocks. The above zero point position may be the raised position of the probe 320 when the stoppers provided on the upper sealing block 100 and the lower sealing block 200, respectively, come into contact. In this way, setting the zero point position prevents the above-mentioned cases where sealing defects are not detected.

[0085] After setting the zero point position, the height increase or change of the probe 320 when the upper sealing block 100 and the lower sealing block 200 are moved relative to each other to actually seal multiple battery cells can be compared with the zero point position to measure the sealing gap or change in the sealing gap during actual battery cell sealing in real time. For example, suppose the servo values ​​of the drive units of the upper and lower sealing blocks are set so that the stoppers of the upper sealing block 100 and the lower sealing block 200 come into contact with each other at the end of the set sealing time, and the height of the probe 320 at the time of stopper contact is set to the zero point position. When the set sealing time ends and the upper sealing block 100 and the lower sealing block 200 begin to move away from each other, if the height of the probe 320 is less than the zero point position or less than the lower limit range set from the zero point position, the sealing gap between the upper sealing block 100 and the lower sealing block 200 needs to be adjusted. In other words, according to the present invention, by comparing the rise of the probe 320 with the above-mentioned zero point position as a reference and measuring the sealing gap or change in the sealing gap in real time, the timing for adjusting the sealing gap can be determined. This makes it possible to quickly detect sealing defects such as excessive sealing thickness, thereby improving the reliability of sealing quality control.

[0086] Furthermore, by saving data on the height and / or height changes of the probe 320 and managing it numerically, the history of the sealing gap and / or sealing thickness represented by the probe height can be quantitatively managed. This makes it possible to track whether a defect in a semi-finished or finished battery cell was caused by sealing quality by checking the history of the sealing data.

[0087] On the other hand, Figure 9 shows the maximum upward limit of the probe 320. When the lower end 321b of the probe is pressurized by the reference block 400 due to the relative movement of the upper sealing block 100 and the lower sealing block 200, the probe's enlarged diameter portion 322 pressurizes the elastic member 340 as it rises. Since the upper end of the elastic member 340 is restricted by the lower end surface of the first guide member 350, the probe 320 cannot rise any further above the probe housing 310 when the elastic member 340 is compressed to its maximum extent between the first guide member 350 and the enlarged diameter portion 322. The probe's raised position at this time becomes the theoretical maximum upward limit. For example, as shown in Figure 6, the maximum upward position of the probe at the smallest sealing gap where the stoppers of the upper and lower sealing blocks make contact can be set to the maximum upward limit position in Figure 9.

[0088] However, Figure 9 shows the theoretical limit of the probe 320's upward movement, and the maximum upward movement of the probe 320 corresponding to the smallest sealing gap at stopper contact does not necessarily have to be at the position shown in Figure 9. In other words, the maximum upward movement of the probe 320 can be determined within the range between Figure 8 and Figure 9.

[0089] (Second Embodiment) As described above, the sealing gap is inversely proportional to the rise of the probe 320. However, the degree of this inverse proportionality can vary slightly depending on the type and condition of the battery cell, the amount of sealant, the sealing temperature and pressure, or the movement speed of the upper sealing block 100 and the lower sealing block 200. For example, data on the sealing gap corresponding to the height rise of the probe 320 can be obtained in advance for each type of battery cell or for each sealing temperature and pressure, and the actual height rise detected can be compared with this sealing gap data to measure (confirm) the sealing gap of the upper sealing block 100 and the lower sealing block 200 in real time. Furthermore, the measured sealing gap can be compared with sealing gap data corresponding to a sealing defect to determine whether or not the sealing is defective.

[0090] The sealing device 1000 of this embodiment further includes a determination unit 500 that measures the sealing gap at the time of sensing by comparing the height increase of the sensed probe 320 with sealing gap data corresponding to that height increase, and determines whether or not there is a sealing defect by comparing the measured sealing gap with sealing gap data corresponding to a sealing defect.

[0091] If necessary, the present invention may further include a data storage unit 600 in which data relating to the sealing gap corresponding to the height increase of the probe 320 and data relating to the sealing gap corresponding to a sealing defect are pre-stored. Alternatively, the correlation between the height increase of the probe 320 and the sealing gap (i.e., the correlation regarding the degree of inverse proportion) can be determined in advance and stored in the data storage unit 600. Once such a specific correlation is determined, the height increase of the probe can be sensed by the sealing device 1000 of the present invention, and the sealing gap can be immediately determined in real time from the correlation.

[0092] Therefore, the determination unit 500 can measure the sealing gap at the time of detection by the sensing unit 330 from the height increase of the probe and the corresponding sealing gap data or correlation data between the height increase and the sealing gap, and compare it with sealing gap data corresponding to a sealing defect to determine whether or not there is a sealing defect.

[0093] (Third embodiment) Figure 10 is a schematic diagram showing the main parts of a sealing device according to another embodiment of the present invention.

[0094] The sensing unit 330 may include heat-sensitive electronic components such as a light sensor or a position sensor.

[0095] The sealing gap measuring unit 300 is coupled to the upper sealing block 100, which is equipped with a heating block 120. Therefore, the sensing unit 330 of the sealing gap measuring unit 300 may be damaged by the heat from the heating block 120, or its measurement sensitivity may be affected.

[0096] In this embodiment, in order to protect the sensing unit 330, a cover member 370 is installed between the heating block of the upper sealing block 100 and the sealing gap measuring unit 300 to block the heat from the heating block.

[0097] As shown in Figure 10, the sealing gap measuring section 300 is coupled to the upper sealing block 100 via the cover member 370. Preferably, the cover member 370 is configured as a cover that covers the front of the sealing gap measuring section 300, particularly the sensing section 330. The cover member 370 may be a heat sink made of metal or plastic. If necessary, heat dissipation fins capable of dissipating heat may be arranged on at least one side of the cover member 370.

[0098] The cover member described above may be installed integrally with or separately from the mounting bracket B described above.

[0099] On the other hand, the upper surface of the reference block 400 that contacts the lower end of the probe must be a flat surface. Also, since the probe 320 is repeatedly in contact with and pressurized by the reference block 400, the probe 320 and the reference block can be made of a highly rigid material, such as titanium or a titanium alloy.

[0100] Furthermore, in the embodiments described above, it was explained that both the upper and lower sealing blocks move. However, the sealing device of the present invention is also applicable when the upper sealing block is fixed and the lower sealing block moves, or when the lower sealing block is fixed and the upper sealing block moves.

[0101] The above description is merely illustrative of the technical concept of the present invention, and a person with ordinary skill in the art to which the present invention belongs can make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the drawings disclosed herein are for illustrative purposes only, not to limit the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by such drawings. The scope of protection of the present invention should be interpreted by the claims, and all technical concepts within an equivalent scope should be interpreted as being included in the scope of rights of the present invention. [Explanation of Symbols]

[0102] 100: Upper sealing block 110: Drive unit 120: Heating Block 121: Stopper 130: Sealing section 200: Lower sealing block 210: Drive unit 220: Heating Block 221: Stopper 230: Sealing section B: Mounting bracket 300: Sealing gap measurement section 310: Probe Housing 311: Through hole 320: Probe 321: Main body 322: Probe diameter expansion section 330: Sensing part 340: Elastic material 350: First guide member 351: Main body 352: Guide diameter expansion section 360: Second guide member 400: Reference Block 500: Judgment section 600: Data storage unit G1, G2: Sealing gap

Claims

1. An upper sealing block and a lower sealing block are positioned above and below the battery cell, and move relative to each other to pressurize and seal the portion of the battery cell to be sealed. The sealing gap measuring section to which the upper sealing block is connected, It includes a reference block coupled to the lower sealing block opposite to the sealing gap measuring portion, The sealing gap measuring unit includes a probe housing coupled to the upper sealing block, a probe whose ends protrude from the upper and lower parts of the probe housing, respectively, and which is installed penetrating the probe housing so as to be movable relative to the probe housing, and a sensing unit that senses the height or height change of the probe protruding from the upper part of the probe housing. The probe comprises a main body and a probe diameter expansion portion having a larger diameter than the main body. An elastic member is provided within the probe housing, with one end supported on the probe housing side and the other end supported on the probe's enlarged diameter portion, thereby applying downward pressure to the probe. A sealing device wherein, when the sealing gap, which is the distance between the upper sealing block and the lower sealing block, changes from the sealing start time when the upper sealing block and the lower sealing block approach each other and pressurized sealing of the battery cell begins, to the sealing end time, the probe is pressed downward by the elastic force of the elastic member, and the lower end of the probe is kept in constant contact with the reference block throughout the entire sealing period from the sealing start time to the sealing end time, and the probe rises relative to the probe housing as the lower end of the probe is pressed against the reference block in accordance with the change in the sealing gap, and the sealing gap or the change in the sealing gap during sealing of the battery cell is measured from the sealing start time to the sealing end time, in accordance with the change in the sealing gap, based on the amount of height rise of the probe sensed by the sensing unit.

2. The sealing device according to claim 1, wherein the upper sealing block and the lower sealing block each include a heating block for heating the part to be sealed and a sealing part coupled to the lower part of the heating block.

3. The sealing gap measuring units are installed on both sides of the upper sealing block, with the sealing portion of the upper sealing block in between. The sealing device according to claim 2, wherein the reference block is installed on both sides of the lower sealing block with the sealing portion of the lower sealing block in between.

4. The sealing device according to claim 1, wherein the sensing unit is a non-contact type displacement sensor for measuring changes in the height of the probe, or a non-contact type position sensing sensor for sensing the upper position of the probe.

5. The sensing unit measures the height rise of the probe at the end of a predetermined set sealing time for each individual battery cell. The sealing device according to claim 1, wherein the sealing gap is measured based on the amount of height rise of the probe at the aforementioned termination point.

6. The probe housing is provided with a through hole for housing the probe, The sealing device according to claim 1, wherein the main body of the probe comprises a first end and a second end that protrude from the upper and lower parts of the probe housing, respectively, and the enlarged diameter portion of the probe is housed in the through hole of the probe housing between the first end and the second end.

7. The elastic member is wound around the main body, The sealing device according to claim 6, wherein the probe is moved downward relative to the probe housing by the elastic force of the elastic member and moved upward relative to the probe housing by the pressure applied by the reference block.

8. A first guide member is coupled to the upper inner circumferential surface of the through hole and has a first guide hole into which the probe is inserted, The present invention further includes a second guide member coupled to the lower inner circumferential surface of the through hole and having a second guide hole into which the probe is inserted, The sealing device according to claim 7, wherein the elastic member is wound around the probe portion between the lower end of the first guide member and the probe diameter enlargement portion, and is positioned between the outer circumferential surface of the probe and the inner circumferential surface of the through hole.

9. The first guide member has a guide body portion that is coupled to the upper inner circumferential surface of the through hole, and a guide diameter enlargement portion that is fixedly coupled to the upper surface of the probe housing at the upper part of the guide body portion. The sealing device according to claim 8, wherein the guide body and the guide diameter expansion portion are provided with a first guide hole into which the probe is inserted.

10. The elastic member has an elastic force set to be biased downward, The sealing device according to claim 8, wherein the probe moves downward as the probe's enlarged diameter portion is pressed downward by the elastic force of the elastic member, but the probe's enlarged diameter portion is blocked by the upper end surface of the second guide member, thereby restricting further downward movement of the probe.

11. The sealing device according to claim 8, wherein when the lower end of the probe is pressed against the reference block, the probe's enlarged diameter portion and the probe move upward against the elastic force of the elastic member, and the elastic member is compressed between the lower end of the first guide member and the probe's enlarged diameter portion.

12. Before measuring the sealing gap, the upper sealing block and the lower sealing block are moved relative to each other to determine the raised position of the probe corresponding to the sealing gap where good sealing is achieved, and the determined raised position is set as the zero point position. The sealing device according to claim 1, wherein the height increase or change in the height increase of the probe when the upper and lower sealing blocks are moved relative to each other to actually seal multiple battery cells is compared with the zero point position, and the sealing gap or change in the sealing gap during actual battery cell sealing is measured in real time with respect to the zero point position.

13. The sealing device according to claim 12, wherein the zero point position is the raised position of the probe when the stoppers provided on the upper sealing block and the lower sealing block, respectively, come into contact.

14. The height increase of the probe detected is compared with the corresponding ceiling gap data to measure the ceiling gap at the time of detection. The sealing apparatus according to claim 1, further comprising a determination unit that determines whether or not there is a sealing defect by comparing the measured sealing gap with sealing gap data corresponding to a sealing defect.

15. The sealing device according to claim 2, wherein the sealing gap measuring portion is coupled to the upper sealing block with a cover member interposed between the heating block and the sealing gap measuring portion of the upper sealing block to block the heat of the heating block.

Images