Penetration test apparatus including zero-point adjustment apparatus and penetration test method using same

Abstract

The present invention relates to a penetration test apparatus and a penetration test method using same, wherein the penetration test apparatus comprises: an upper surface pressure plate that presses the upper surface of a battery cell; a lower surface pressure plate that presses the lower surface of the battery cell; a through-hole provided in the upper surface pressure plate; a nail that penetrates the battery cell through the through-hole; and a zero-point adjustment unit that protrudes outward from one outer periphery of the upper surface pressure plate. Accordingly, a zero-point that serves as a reference point for a position where the nail is inserted can be accurately set.

Description

Penetration test device including a zero-point adjustment device and a penetration test method using the same

[0001] This application claims the benefit of priority to Korean Patent Application No. 2023-0180150, filed December 12, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a penetration test device including a zero-point adjustment device and a penetration test method using the same. Specifically, the present invention relates to a penetration test device including a zero-point adjustment device for setting the zero-point position of a nail during a penetration test of a pouch-type battery cell, and a penetration test method using the same.

[0003]

[0004] Explosions of lithium secondary batteries can have a serious impact on the lives of users, making safety assessment testing essential. Internal short circuits, overcharging, and overdischarging are major factors affecting the safety of lithium secondary batteries. Penetration testing, which identifies the impact of internal short circuits, is considered the most critical of all assessment tests.

[0005] A penetration test is a method of observing whether a nail, a pointed metal needle-shaped conductor, penetrates a battery cell or induces an internal short circuit in the battery to a certain depth, resulting in ignition or explosion. The depth of the nail inserted from the surface of the battery cell to the inside is quantified to a certain value, and ignition or explosion is confirmed when the nail is inserted to this depth. However, it is not easy to accurately measure the depth of the nail inserted through a penetration hole formed at the center of a plate-shaped member.

[0006] Patent Document 1 discloses an indentation test device configured to place a zero-point auxiliary jig having a reference height between the upper surface of a battery and a nail, move the attachment of the nail to the upper end of the zero-point auxiliary jig placed on the battery to measure the position of the nail, compensate the reference height for the measured position to set a zero value, and use the zero value during an indentation test so that the attachment of the nail is positioned on the surface of the battery.

[0007] Patent Document 1 describes a method for conducting a press-fit test by inserting and securing a battery within a test jig formed as a box structure with a predetermined internal space. If a pouch-type battery cell is not pressed with a consistent force, the battery case and electrode assembly may not be in close contact. This can result in a discrepancy between the nail insertion depth and the preset depth.

[0008] Patent Document 1 does not have the same degree of deformation in its external appearance as a pouch-type battery, as it is a square battery inserted into a metal case, and thus does not require a jig to pressurize the battery beyond a certain pressure. Patent Document 1 also discloses that the zero-point auxiliary jig, which determines the zero point position, is a cylindrical object, and if this is used with a pouch-type battery, problems may arise if the laminate sheet of the pouch-type battery is not completely flat.

[0009] Patent document 2 relates to an all-solid-state battery cell penetration test device, comprising: a pressurizing portion that pressurizes a battery cell; a penetration member that is inserted through a penetration hole formed in the pressurizing portion and penetrates the battery cell; and an auxiliary pressurizing portion that is disposed between the pressurizing portion and the battery cell and transmits the pressure applied by the pressurizing portion to the battery cell, wherein the auxiliary pressurizing portion is disposed between the penetration hole and the battery cell in a manner that blocks the penetration hole.

[0010] Patent Document 2 is difficult to use for a penetration test to cause an internal short circuit because the auxiliary pressurizing part blocks the penetration hole in the pressurizing part, making it difficult to insert the penetration member into the battery cell.

[0011] In Patent Document 2, the voltage measurement is performed to measure the voltage between the positive terminal of the battery and the nail during the penetration test, unlike the measurement of the exact position of the zero point performed in the present invention, and this is to determine the characteristics of the penetration step.

[0012] As a penetration test device for artificially causing an internal short circuit, Fig. 1 illustrates a perspective view of a conventional penetration test device.

[0013] Referring to FIG. 1, the penetration test device includes an upper pressure plate (110) disposed on an upper surface of a battery cell (10), a lower pressure plate (210) disposed on a lower surface of the battery cell (10), and a nail (300) that penetrates the battery cell (10). The battery cell (10) is fixed in a state of being pressed at a predetermined pressure by the upper pressure plate (110) and the lower pressure plate (210), and a through hole (130) for the nail (300) to pass through is formed in the center of the upper pressure plate (110). An insulating film (111) is attached to the lower surface of the upper pressure plate (110) and the upper surface of the lower pressure plate (210) to prevent short circuiting of the battery cell (10).

[0014] The nail (300) is inserted into the hole (130), and the structure is such that it is difficult for the worker to confirm the zero point, which is the position where the nail (300) comes into contact with the surface of the battery cell (10) and serves as the reference for the insertion depth.

[0015] In order to solve this problem, a method was used in which a plastic hexahedron (20) having a thickness corresponding to or thinner than the thickness of the battery cell (10) was inserted between the upper pressure plate (110) and the lower pressure plate (210), and a nail (300) was brought into contact with the upper surface of the plastic hexahedron (20) to set the zero point. Since the surface of the plastic hexahedron (20) is not flat, and the position where the nail (300) is judged to have come into contact with the surface of the plastic hexahedron (20) is set as the zero point depending on the eyes and feel of the worker, the zero point reference may vary depending on the worker.

[0016] The upper pressure plate (110) has an insulating film (111) attached to the lower surface. If the insulating film (111) is not attached to the position where the plastic hexahedron (20) is interposed, the height of the plastic hexahedron (20) does not take into account the thickness of the insulating film (111), and thus a deviation occurs by the thickness of the insulating film (111).

[0017] As an example, a test may be performed on a battery cell to penetrate 2.2 mm from the surface of the battery cell, or a test may be performed on an electrode assembly within a battery cell to penetrate 3 to 5 sets of monocells. In this case, if the test is performed using a conventional method or a method such as that of Patent Document 1, the plastic hexahedron (20) may not be properly aligned, errors due to the thickness of the insulating film (111) may not be considered, or an accurate test may not be performed due to an uneven surface of the pouch-type battery cell case. When a conventional penetration test device is applied in the field, a problem occurs in which the presence or absence of a product defect varies depending on the measurer performing the actual test.

[0018] In this way, a technology is needed to enable a penetration test to be performed while the battery cell is in close contact with the battery case and the electrode assembly so that no space is formed between them, and to set a zero point so that the accuracy and reliability of the penetration test can be increased by inserting the nail to a preset nail insertion depth.

[0019]

[0020] (Prior art literature)

[0021] (Patent Document 1) Korean Patent Publication No. 2023-0006265 (January 10, 2023)

[0022] (Patent Document 2) Korean Patent Application Publication No. 2023-0061044 (May 8, 2023)

[0023]

[0024] The present invention is intended to solve the above problems, and provides a penetration test device equipped with a zero-point adjustment device that can accurately set a zero point, which serves as a reference for the insertion depth of a nail, regardless of the measurer, and conduct a test under conditions that meet the penetration test standards, thereby increasing the reliability of the results, and a penetration test method using the same.

[0025]

[0026] A penetration test device according to the present invention for achieving this purpose may include an upper pressure plate for pressing an upper surface of a battery cell, a lower pressure plate for pressing a lower surface of the battery cell, a through hole provided in the upper pressure plate, a nail for penetrating the battery cell through the through hole, and a zero-point adjustment unit protruding outward from an outer periphery of one side of the upper pressure plate.

[0027] It may further include a resistance measuring unit for checking whether the nail and the zero point adjustment unit are in contact.

[0028] The resistance measuring unit includes a first terminal and a second terminal, the first terminal being connected to the nail, and the second terminal being coupled to the zero adjustment unit.

[0029] The upper surface of the above zero point adjustment unit may be positioned on the same plane as the lower surface of the upper pressure plate.

[0030] An insulating film may be attached to the lower surface of the above upper pressure plate.

[0031] The first region of the above zero adjustment unit may be attached so that its upper surface overlaps the lower surface of the upper pressure plate, and the second region of the above zero adjustment unit may be positioned so as to protrude outward from the outer surface of the upper pressure plate.

[0032] The first region of the above zero point adjustment unit can be attached to the lower surface of the upper pressure plate through an adhesive member.

[0033] It may include a pressure control means that can control the size of the force applied to the battery cell by the upper pressure plate and the lower pressure plate.

[0034] A penetration test method using the above penetration test device may include a first step of fixing a battery cell between an upper pressure plate and a lower pressure plate, a second step of setting a zero point by contacting a nail with a zero point adjustment unit, and a third step of penetrating the battery cell with the nail.

[0035] The above first step may be performed as a process of adjusting the positions of the upper and lower pressure plates so that the upper and lower pressure plates are in close contact with the battery cell.

[0036] In the second step, the nail can be brought into contact with the upper surface of the zero-point adjustment unit, and the position where the resistance of the resistance measuring unit connected to each of the nail and the zero-point adjustment unit becomes 0 can be set as the zero point.

[0037] The process of bringing the nail into contact with the upper surface of the zero point adjustment unit can be performed twice in succession.

[0038] The second step may include a process of bringing the nail close to the upper portion of the zero adjustment unit and then moving the nail at a speed of 0.1 mm / s until it comes into contact with the zero adjustment unit.

[0039] The above third step can be performed until the insertion depth of the nail reaches a set value.

[0040] The present invention can also be provided in a form in which various means for solving the above problem are combined.

[0041]

[0042] As described above, the penetration test device according to the present invention includes an upper pressure plate and a lower pressure plate for pressurizing a battery cell, so that the height of the battery cell can be kept constant, and a state in which the upper surface of the electrode assembly and the battery case are in close contact in a pouch-type battery cell can be created.

[0043] In addition, since a zero point adjustment unit is provided taking into account the thickness of the insulating film attached to the upper pressure plate, the zero point, which serves as a reference for the insertion depth of the nail, can be accurately set starting from the surface of the battery cell.

[0044]

[0045] Figure 1 is a perspective view of a conventional penetration test device.

[0046] Figure 2 is a perspective view of a penetration test device according to the present invention.

[0047] Figure 3 is a vertical cross-sectional view taken along line A-A' of Figure 2.

[0048] Fig. 4 is a vertical cross-sectional view of Fig. 3 with a pressure control means added.

[0049] Figure 5 is a plan view of the upper pressure plate and lower pressure plate of Figure 2.

[0050] Figure 6 is a graph showing the pressure applied according to the insertion depth of the nail during a penetration test according to an embodiment.

[0051] Figure 7 is a graph measuring the pressing force according to the insertion depth of the nail during a penetration test according to a comparative example.

[0052]

[0053] Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail, so that those skilled in the art can easily implement the present invention. When describing the operating principles of the embodiments of the present invention in detail, detailed descriptions of known functions or components will be omitted if they are deemed to unnecessarily obscure the gist of the present invention.

[0054] Parts with similar functions and actions are designated by the same drawing reference numerals throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only direct connections but also indirect connections with other elements intervening. Furthermore, inclusion of a component does not exclude other components unless otherwise specifically stated, but rather implies the inclusion of additional components.

[0055] The description that concretizes or adds to the components may be applied to all inventions unless there is a special limitation, and is not limited to the description of a specific invention.

[0056] Throughout the description and claims of the invention herein, the singular includes the plural unless otherwise stated.

[0057] Throughout the description and claims of the present invention, the term "or" includes "and" unless otherwise stated. Therefore, "comprising A or B" means all three cases of including A, including B, or including A and B.

[0058] The present invention is described in detail with examples according to the drawings.

[0059] Fig. 2 is a perspective view of a penetration test device according to the present invention, and Fig. 3 is a vertical cross-sectional view taken along line A-A' of Fig. 2.

[0060] Referring to FIGS. 2 and 3, the penetration test device according to the present invention includes an upper pressure plate (110) for pressing an upper surface of a battery cell (10), a lower pressure plate (210) for pressing a lower surface of the battery cell (10), a through hole (130) provided in the upper pressure plate (110), a nail (300) for penetrating the battery cell (10) through the through hole (130), and a zero point adjustment part (120) protruding outward from one outer periphery of the upper pressure plate (110).

[0061] The battery cell (10) may include a square battery cell or a pouch-shaped battery cell, and FIG. 2 illustrates a state in which a pouch-shaped battery cell is fixed so as to be pressed by an upper pressure plate (110) and a lower pressure plate (210). The pouch-shaped battery cell may be a bidirectional battery cell in which two electrode leads (11) protrude in opposite directions, or may be a unidirectional battery cell in which two electrode leads protrude in the same direction. As a non-limiting example, the drawing illustrates a bidirectional battery cell in which two electrode leads (11) protrude in opposite directions.

[0062] The present invention can conduct a penetration test by setting in advance the depth of a nail (300) that is pressed into the inside of a battery cell (10) from the surface of the battery cell (10), and checking whether ignition or explosion of the battery cell occurs when the nail presses into the battery cell to the depth set in advance.

[0063] Typically, a separate device is used to drive the nail, allowing the driving speed and depth of the nail to be set and controlled. For example, if the nail is set to penetrate 2.2 mm into the battery cell, the surface of the battery cell is set as the zero point, and the nail is driven in by the preset 2.2 mm, the nail should actually penetrate the battery cell by 2.2 mm.

[0064] If the pressing force of the upper and lower pressing plates that pressurize the battery cell is weak, the penetration test may be conducted in a state where the battery cell is swollen, which may result in the nail not being able to pressurize the electrode assembly to the preset insertion depth.

[0065] Accordingly, the present invention has a zero-point adjustment part (120) protruding outward from one side of the outer periphery of the upper pressure plate (110), and sets the zero point by confirming the state in which the nail (300) and the zero-point adjustment part (120) are in contact.

[0066] Since the nail (300) and the zero point adjustment unit (120) are made of a conductive material that conducts electricity, when they come into contact, electricity is conducted. Therefore, a resistance measuring unit (400) is included to check whether the nail (300) and the zero point adjustment unit (120) are in contact.

[0067] The resistance measuring unit (400) includes a first terminal (401) and a second terminal (402). When the first terminal (401) is connected to the nail (300) and the second terminal (402) is coupled to the zero-point adjustment unit (120), and the nail (300) is brought into contact with the zero-point adjustment unit (120), the resistance measuring unit (400) measures a value within 5 Ohm, which is similar to 0 Ohm. That is, when the nail (300) is not in contact with the zero-point adjustment unit (120), the resistance measuring unit (400) measures no resistance, which is practically infinite, but the moment the nail (300) and the zero-point adjustment unit (120) come into contact, current flows between the nail (300) and the zero-point adjustment unit (120), and a resistance of a magnitude close to 0 Ohm is measured by the resistance measuring unit (400).

[0068] In this specification, the resistance value measured when the nail and the zero point adjustment part come into contact is described as 0 Ohm.

[0069] The zero point adjustment unit (120) is a means for setting the state in which the nail (300) is in contact with the surface of the battery cell (10) as the zero point, and the upper surface (122) of the zero point adjustment unit, which the nail (300) is in contact with, must be located on the same plane as the lower surface of the upper pressure plate (110). Since the lower surface of the upper pressure plate (100) can be considered to be located on the same plane as the upper surface (12) of the battery cell, the upper surface (122) of the zero point adjustment unit can be considered to be located on the same plane as the upper surface (12) of the battery cell.

[0070] In general, since the lower surface of the upper pressure plate (110) and the upper surface of the lower pressure plate (210) are in direct contact with the battery cell (10), an insulating film (111, 211) is attached to them for safety. The insulating film (111, 211) may be configured such that an adhesive layer is provided on one surface of an insulating layer made of an insulating material, and the adhesive layer is attached to the lower surface of the upper pressure plate and the upper surface of the lower pressure plate, respectively.

[0071] The above insulating material is not particularly limited as long as it is a known insulating material. The insulating film (111, 211) may be applied to the entire surface facing the battery cell (10), but the zero-point adjustment unit (120) is configured to protrude from the outer periphery of one side of the upper pressure plate (110), so the insulating film is not attached to the portion where the zero-point adjustment unit (120) protrudes.

[0072] The zero point adjustment unit (120) is configured to protrude from the outer periphery of one side of the upper pressure plate (110) so that the contact of the nail (300) can be easily confirmed with the naked eye from the outside. The first region (120a) of the zero point adjustment unit (120) is attached so that the upper surface overlaps the lower surface of the upper pressure plate (110), and the second region (120b) of the zero point adjustment unit (120) is provided so as to protrude outward from the outer periphery of the upper pressure plate (110).

[0073] The first area (120a) of the zero point adjustment unit (120) is attached to the lower surface of the upper pressure plate (110) via an adhesive member (121). The adhesive member (121) may use an adhesive or double-sided tape.

[0074] The position of the upper surface (122) of the zero-adjustment unit must be corrected by the thickness of the insulating film (111) attached to the lower surface of the upper pressure plate (110). Therefore, it is preferable to attach an adhesive member (121) so as to be interposed between the zero-adjustment unit (120) and the upper pressure plate (110), and to set the thickness of the adhesive member (121) to be similar to or the same as the thickness of the insulating film (111). However, a difference of micrometers may occur between the thickness of the adhesive member (121) and the thickness of the insulating film (111). The insulating film (111) has an adhesive layer added to only one side, while the adhesive member (121) has an adhesive layer added to both sides, which may cause a difference. However, this level of error can be considered to not have a significant effect on the results of the penetration test. For more precise measurement, the insulating film and the adhesive member can be selected by considering the thickness of the adhesive layer.

[0075] Even in this case where the insulating film (111) is attached to the lower surface of the upper pressure plate (110), since the upper surface (122) of the zero-point adjustment unit is bonded to the upper pressure plate (110) through the adhesive member (121), the thickness of the insulating film (111) is compensated for by being offset by the thickness of the adhesive member (121), and thus the upper surface (122) of the zero-point adjustment unit can be viewed as being located on the same plane as the lower surface of the insulating film (111) attached to the lower surface of the upper pressure plate (100). Accordingly, the upper surface (122) of the zero-point adjustment unit is located on the same plane as the upper surface (12) of the battery cell.

[0076] Fig. 4 is a vertical cross-sectional view of Fig. 3 with a pressure control means added, and Fig. 5 is a plan view of the upper and lower pressure plates of Fig. 2. In Fig. 5, an enlarged view is of the upper pressure plate (110), and a plan view of the lower pressure plate (210) is shown below it.

[0077] Referring to FIGS. 4 and 5 along with FIGS. 2 and 3, a pressure control means capable of controlling the magnitude of the force applied to the battery cell (10) by the upper pressure plate (110) and the lower pressure plate (210) is included.

[0078] In FIG. 2 and FIG. 5, six first fastening holes (140) are formed on the upper pressure plate (110), and six second fastening holes (240) are formed on the lower pressure plate (210). FIG. 2 illustrates a form in which a bolt (301) is inserted so as to penetrate one of the first fastening holes (140) and the second fastening hole (240) among these, and the bolt (301) is fixed using a nut (302).

[0079] Figure 2 is for example, and fastening is formed using bolts (301) and nuts (302) in all first fastening holes (140) and all second fastening holes (240), but the spacing between the first fastening holes (140) and the second fastening holes (240) must be the same in all six positions, so that the fastening pressure of the bolts must be the same.

[0080] The pressure control means according to the present invention is not limited to a combination of a bolt (301) and a nut (302), and may include a configuration in which a pressure cylinder is attached to each of the upper pressure plate and the lower pressure plate, or a configuration in which separate pressure members for pressing the upper pressure plate and the lower pressure plate are combined.

[0081] However, if the force pressing the battery cell is too strong or too weak, a penetration test may be performed that does not match the preset nail insertion depth. Therefore, a process of pressing the battery cell multiple times to find the optimal pressurization state may be necessary. For example, when the upper surface of the battery cell is flat and not swollen, it may be in an appropriate pressurized state. In addition, considering that the pressure for fixing the battery cell when fixing the battery cell to a jig and performing a cycle test is typically about 4 kgf, it may be in a pressurized state with a greater force than this. Specifically, the force pressing the battery cell may be 5 kgf to 50 kgf.

[0082] If the battery cell is pressed with a force less than 5 kgf, the battery cell may be in an over-expanded state, so even if the nail is pressed in to the preset depth, the actual depth of penetration of the battery cell will inevitably be shallower. When pressing in the nail, the pressure applied to the nail can be measured, and if it is confirmed that the pressure applied to the nail does not reach the reference pressure, it can be determined that the battery cell is pressed with a force less than 5 kgf.

[0083] The bonding pressure may be determined differently for each battery cell and is determined by the electrochemical criteria of the battery cell, so qualitative rather than quantitative criteria should be provided.

[0084] A penetration test method using a penetration test device according to the present invention includes a first step of fixing a battery cell (10) between an upper pressure plate (110) and a lower pressure plate (210), a second step of setting a zero point by contacting a nail (300) with a zero point adjustment unit (120), and a third step of penetrating the battery cell (10) with the nail (300).

[0085] The above first step may be performed as a process of adjusting the positions of the upper pressure plate (110) and the lower pressure plate (210) so that the upper pressure plate (110) and the lower pressure plate (210) are in close contact with the battery cell (10).

[0086] The above second step may be carried out by bringing the nail (300) into contact with the upper surface of the zero point adjustment unit (120) to set the position where the resistance of the resistance measurement unit (400) connected to each of the nail (300) and the zero point adjustment unit (120) becomes 0 Ohm as the zero point.

[0087] During the process of setting the zero point, the speed at which the nail (300) moves downward toward the zero point adjustment unit (120) is important in order to accurately measure the moment when the nail (300) and the zero point adjustment unit (120) come into contact and to prevent the tip of the nail (300) from being damaged. For example, when the nail (300) moves close enough not to touch the zero point adjustment unit (120), it moves downward at a speed of 5 mm / s, and when the nail (300) approaches the zero point adjustment unit (120), it moves downward at a speed of 0.1 mm / s until the nail (300) and the zero point adjustment unit (120) come into contact, and the current measurement unit is checked.

[0088] At this time, in order to more accurately confirm the zero point position, the process of bringing the nail (300) into contact with the upper surface of the zero point adjustment unit (120) can be performed twice in succession.

[0089] The above third step can be performed until the insertion depth of the nail (300) reaches a set value.

[0090] In this way, the present invention can accurately perform a penetration test according to a preset insertion depth by setting the zero point, which is the surface position of the battery cell, using the zero point adjustment unit while the battery cell is pressed with an appropriate force. Since the nail (300) is provided with a means for measuring its own position, the relative displacement can be determined after the zero point is set. In addition, the value of the set zero point can be determined through the value of the measuring unit provided on the nail (300) itself.

[0091] That is, the value set as the zero point is confirmed through the measuring unit provided in the nail (300) itself. Afterwards, the nail (300) is moved upwards to separate from the zero point adjustment unit (120) and then moved horizontally to the position of the aperture (130). The nail (300) is moved downwards from the position of the aperture (130) to the value set as the previously confirmed zero point. At this time, the value set as the previously confirmed zero point can be confirmed through the measuring unit provided in the nail (300) itself. Afterwards, an actual penetration test is performed.

[0092]

[0093] In the following, in order to determine what effect the upper and lower pressure plates have on the penetration test of the battery cell when the pressing force on the battery cell is too weak and when it is appropriate, a case where the pressing force is weak is described as a comparative example, and a case where the pressing force is appropriate is described as an example.

[0094]

[0095] The appropriate size of the above pressing force is determined by the electrochemical standard of the battery cell, and in the examples of this specification, 5 kgf to 50 kgf is considered to be an appropriate size, and the comparative example is when the pressing force is 4 kgf, and the example is when the pressing force is 20 kgf.

[0096]

[0097] <Example>

[0098] A penetration test device as shown in Fig. 2 is prepared, a pouch-shaped battery cell is placed between an upper pressure plate and a lower pressure plate, and the pressing force for pressing the pouch-shaped battery cell is set to 20 kgf, thereby pressing the pouch-shaped battery cell with the upper pressure plate and the lower pressure plate.

[0099] Set the zero point on the outer surface of the pouch-type battery cell by touching the nail to the zero point adjustment part.

[0100] The nail was placed through the hole of the upper pressure plate so that it was at the same position as the zero point, and the force with which the nail pressed the pouch-type battery cell was measured while the nail was pressed so that it penetrated the pouch-type battery cell by 2.2 mm from the zero point.

[0101] Figure 6 is a graph showing the pressure applied according to the insertion depth of the nail during a penetration test according to an embodiment.

[0102]

[0103] <Comparative Example>

[0104] A penetration test was conducted in the same manner as in the above example, except that the force applied to the pouch-shaped battery cell by the upper and lower pressure plates was 4 kgf.

[0105] Figure 7 is a graph measuring the pressing force according to the insertion depth of the nail during a penetration test according to a comparative example.

[0106]

[0107] Referring to FIGS. 6 and 7, the horizontal axis represents the distance between the nail and the pouch-type battery cell. When the zero point, which is the surface of the pouch-type battery cell, is taken as 0.0, - represents before the nail comes into contact with the pouch-type battery cell, and as it increases from 0.0, it represents the insertion depth of the nail into the interior of the pouch-type battery cell. The vertical axis represents the magnitude of the pressing force applied by the nail to the pouch-type battery cell.

[0108]

[0109] In the case where the thickness of the battery case is 0.18 mm, the graph of Fig. 6 shows a tendency for the pressing force to gradually increase from the 0.18 mm point, and it can be seen that the nail penetrated the electrode assembly of the pouch-type battery cell to the preset nail insertion depth of 2.2 mm. Therefore, in the embodiment, it can be confirmed that the penetration test was conducted while the upper and lower pressing plates sufficiently pressed the pouch-type battery cell.

[0110]

[0111] The graph of Fig. 7 shows a case where the upper and lower pressure plates have a weak force to press the pouch-type battery cell. The pressing force of the nail does not increase when the nail insertion depth is from 0.0 mm to 1.0 mm, and the pressing force tends to increase from the 1.0 mm point. In other words, it can be seen that the electrode assembly of the pouch-type battery cell is not penetrated from 0.0 mm to 1.0 mm.

[0112] Therefore, the penetration test must be conducted in a state where the battery case of the pouch-type battery cell is fully pressurized by the upper and lower pressurized plates so that it is not expanded, so that the nail can be considered to have been inserted to the preset nail insertion depth, and the reliability of the safety evaluation of the pouch-type battery cell can be secured.

[0113]

[0114] Anyone with ordinary knowledge in the field to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

[0115] (Explanation of symbols)

[0116] 10: Battery cell

[0117] 11: Electrode lead

[0118] 12: Top surface of the battery cell

[0119] 20: Plastic cube

[0120] 110: Top pressure plate

[0121] 111, 211: Insulating film

[0122] 120: Zero point adjustment unit

[0123] 120a: Area 1

[0124] 120b: Area 2

[0125] 121: Adhesive member

[0126] 122: Top surface of the zero point adjustment unit

[0127] 130: Public

[0128] 140: First fastener

[0129] 210: Lower pressure plate

[0130] 240: Second fastener

[0131] 300: Nail

[0132] 301: Volt

[0133] 302: Nut

[0134] 400: Resistance measurement unit

[0135] 401: Terminal 1

[0136] 402: Second terminal

Claims

1. Upper pressure plate for pressing the upper surface of the battery cell; A lower pressure plate for pressurizing the lower surface of the above battery cell; A perforation provided in the upper surface pressure plate; A nail penetrating the battery cell through the above-mentioned hole; and A zero-point adjustment part protruding outward from one outer periphery of the upper surface pressure plate; A penetration test device including:

2. In paragraph 1, A penetration test device further comprising a resistance measuring unit for checking whether the nail and the zero point adjustment unit are in contact.

3. In paragraph 2, The above resistance measuring unit includes a first terminal and a second terminal, A penetration test device in which the first terminal is connected to the nail and the second terminal is coupled to the zero point adjustment unit.

4. In paragraph 1, A penetration test device in which the upper surface of the above zero point adjustment part is located on the same plane as the lower surface of the above upper pressure plate.

5. In paragraph 1, A penetration test device having an insulating film attached to the lower surface of the upper pressure plate.

6. In paragraph 1, A penetration test device in which the first region of the above zero-adjustment part is attached so that its upper surface overlaps the lower surface of the above upper pressure plate, and the second region of the above zero-adjustment part is positioned so as to protrude outward from the outer surface of the above upper pressure plate.

7. In paragraph 6, A penetration test device in which the first region of the above zero point adjustment part is attached to the lower surface of the upper pressure plate through an adhesive member.

8. In paragraph 1, A penetration test device including a pressure control means capable of controlling the size of the force applied to the battery cell by the upper pressure plate and the lower pressure plate.

9. In a penetration test method using a penetration test device according to any one of clauses 1 to 8, Step 1: fixing the battery cell between the upper and lower pressure plates; Step 2: Setting the zero point by contacting the nail with the zero point adjustment part; and A third step of penetrating the battery cell with the nail; A penetration test method including:

10. In paragraph 9, The above first step is a penetration test method in which the positions of the upper and lower pressure plates are adjusted so that the upper and lower pressure plates are in close contact with the battery cell.

11. In paragraph 9, The second step is a penetration test method in which the nail is brought into contact with the upper surface of the zero-point adjustment unit, and the position at which the resistance of the resistance measuring unit connected to each of the nail and the zero-point adjustment unit becomes 0 is set as the zero point.

12. In paragraph 11, A penetration test method in which the process of bringing the nail into contact with the upper surface of the zero point adjustment part is performed twice consecutively.

13. In paragraph 11, The second step is a penetration test method including a process of bringing the nail close to the upper part of the zero-adjustment part and then moving the nail at a speed of 0.1 mm / s until the nail comes into contact with the zero-adjustment part.

14. In paragraph 9, The above third step is a penetration test method that is performed until the insertion depth of the nail reaches a set value.

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