Thermal runaway test fixture for battery

Abstract

A thermal runaway test fixture for a battery includes: a nail assembly including a nail at a lower portion thereof; and a staple holder that accommodates the staple assembly. The thermal runaway test fixture for the battery has the effect of improving the accuracy and safety of stability evaluation of the battery module.

Description

Technical Field

[0001] The present disclosure relates to a thermal propagation test jig for a battery, and more particularly, to a battery cell bottom nail destruction test jig for a battery module. Background Art

[0002] Unlike non-rechargeable primary batteries, secondary batteries refer to batteries that can be charged and discharged, and are applied not only to portable devices but also to electric vehicles (EVs) and hybrid electric vehicles (HEVs) driven using an electric drive source.

[0003] The types of secondary batteries currently in widespread use include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and the like. The operating voltage of such a unit secondary battery cell (i.e., a unit battery cell) is approximately 2.5V to 4.2V. Therefore, when a higher output voltage is required, a battery pack is formed by connecting a plurality of battery cells in series. In addition, a battery pack is formed by connecting a plurality of battery cells in parallel according to the charge and discharge capacity required for the battery pack. Therefore, the number of battery cells included in the battery pack can be set in various ways according to the required output voltage or charge and discharge capacity.

[0004] When a battery pack is constructed by connecting multiple battery cells in series or in parallel, a battery module consisting of at least one battery cell (preferably, multiple battery cells) is generally constructed first, and then a battery pack is constructed using the at least one battery module and adding other components. Here, a battery module refers to a component in which multiple battery cells are connected in series or in parallel, and a battery pack may refer to a component in which multiple battery modules are connected in series or in parallel to increase capacity and output.

[0005] However, in such battery modules and battery packs, if there is overcharge or the like, explosion or fire may occur due to swelling of the battery module, and such explosion or fire may result in a greater risk of causing casualties.

[0006] Therefore, stability evaluation of battery modules or battery packs is required. Summary of the Invention

[0007] Technical issues

[0008] An object of the present disclosure is to provide a thermal runaway test fixture for a battery that can improve the accuracy of battery module stability assessment.

[0009] Technical Solution

[0010] A thermal runaway test jig for a battery according to an embodiment of the present disclosure includes a nail assembly, the nail assembly including a nail at a lower portion, and a nail holder configured to accommodate the nail assembly.

[0011] Additionally, the staples may be removably coupled to the staple assembly.

[0012] Furthermore, the nail assembly may include a coupling groove to which the nail is coupled.

[0013] Furthermore, the nail assembly includes a plurality of nails.

[0014] In addition, the nail assembly further includes a pressure rod.

[0015] In addition, the thermal runaway test fixture may further include an upper coupling groove, to which the pressure rod is coupled.

[0016] Furthermore, the staple holder may include an insertion slot into which the staple assembly is inserted.

[0017] Additionally, the staple assembly can be configured to be movable up and down within the insertion slot.

[0018] Furthermore, the bottom of the insertion groove may be provided to be spaced apart from the lower end of the nail holder.

[0019] In addition, the nail holder may further include a passage hole for the nail to pass through on the lower side of the insertion groove.

[0020] Furthermore, the passage hole may extend from the bottom of the insertion slot to the lower end of the nail holder.

[0021] In addition, the lower portion of the nail holder is provided with a plurality of passage holes for respectively passing the plurality of nails.

[0022] In addition, the nail holder may further include a pair of upper protrusions protruding upward at an upper portion of the nail holder.

[0023] Beneficial effects

[0024] The thermal runaway test fixture for a battery according to the present disclosure has the effect of improving the accuracy and safety of battery module stability evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a diagram showing a thermal runaway test box used in the present disclosure.

[0026] Figure 2 It shows Figure 1 A diagram of the interior of the thermal runaway test box is shown in FIG.

[0027] Figure 3 yes Figure 1 A longitudinal cross-sectional view of the thermal runaway test box is shown in FIG.

[0028] Figure 4 It is a cross-sectional perspective view of a cylindrical battery cell.

[0029] Figure 5 FIG. 1 is a diagram illustrating a state in which a thermal runaway test jig according to the present disclosure is set in a thermal runaway test box.

[0030] Figure 6 FIG. 1 is a longitudinal cross-sectional view showing a state in which the thermal runaway test jig according to the present disclosure is set in a thermal runaway test box.

[0031] Figure 7 is a perspective view of a thermal runaway test fixture for a battery according to the present disclosure.

[0032] Figure 8 yes Figure 7 A longitudinal cross-sectional view of a thermal runaway test fixture for a battery is shown in FIG.

[0033] Figure 9 yes Figure 7 A detailed view of a thermal runaway test fixture for batteries is shown in FIG.

[0034] Figure 10 yes Figure 7 FIG. 4 is a diagram showing the interior of a thermal runaway test fixture for a battery. FIG.

[0035] Figure 11 FIG. 1 is a diagram illustrating a state in which the thermal runaway test jig for a battery according to the present disclosure is used in a thermal runaway test box. DETAILED DESCRIPTION

[0036] The advantages and features of the present disclosure and their implementation methods will become clear with reference to the embodiments described below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but can be implemented in various different forms, and these embodiments are provided only to make the present disclosure complete and to fully inform those skilled in the art of the scope of the present disclosure, and the present disclosure is limited only by the scope of the claims. Therefore, in some embodiments, well-known process steps, well-known device structures and well-known technologies are not described in detail to avoid ambiguity when interpreting the present disclosure. Throughout the specification, the same figure marks refer to the same parts.

[0037] In the accompanying drawings, the thickness may be exaggerated to clearly indicate the various layers and regions. Throughout this specification, the same reference numerals are used for similar components. When a component such as a layer, film, region, or plate is described as being "located on" another component, this includes not only the situation where it is "directly located on" the other component, but also the situation where another component exists between them. Conversely, when a component is described as being "directly located on" another component, this means that there are no other components between them. In addition, when a component such as a layer, film, region, or plate is described as being "below" another component, this includes not only the situation where it is "directly located "below" the other component, but also the situation where other components exist between them. Conversely, when a component is described as being "directly located "below" another component, this means that there are no other components between them.

[0038] Before describing the thermal runaway test fixture 1000 for a battery according to the present disclosure, reference will be made to Figures 1 to 5 A thermal runaway test box 10 for a multi-cell stack for thermal runaway testing will be described.

[0039] Figure 1 is a diagram showing a thermal runaway test box used in the present disclosure, Figure 2 It shows Figure 1 The diagram of the interior of the thermal runaway test box is shown in Figure 3 yes Figure 1 A longitudinal cross-sectional view of the thermal runaway test box is shown in FIG. Figure 4 is a perspective view of a cross section of a cylindrical battery cell, and Figure 5 FIG. 1 is a diagram illustrating a state in which a thermal runaway test jig according to the present disclosure is set in a thermal runaway test box.

[0040] The stability of multi-cell modules (thermal runaway cascading fire) can be verified by applying external impact / energy to a portion of the battery cells and then destroying them. The stability of multi-cell modules is usually evaluated through nail tests, overcharge tests, and heater tests.

[0041] Among them, due to the structure of the multi-battery cell module, the nail test can be performed at the bottom of the battery cell (exhaust direction).

[0042] The thermal runaway test fixture 1000 for a battery according to the present disclosure may be used for a nail test.

[0043] The thermal runaway test cartridge 10 may include a plurality of battery cells 100 , a cartridge case 200 , and a middle frame 300 .

[0044] The battery cell 100 may be a cylindrical battery cell 100 in which an electrode assembly is built into a metal can. Figure 4 It is a cross-sectional perspective view of a cylindrical battery cell 100 .

[0045] The cylindrical battery cell 100 may include a wound electrode assembly 110 and a battery case 120 for accommodating the electrode assembly 110 , an upper insulating member 150 may be positioned at an upper end of the electrode assembly 110 , and a lower insulating member 160 may be positioned at a lower end of the electrode assembly 110 .

[0046] The electrode assembly 110 has a wound roll-shaped structure in which a negative electrode 111 , a positive electrode 113 , and a separator 112 interposed therebetween are wound, and a center pin 140 may be inserted into the center of the electrode assembly 110 .

[0047] The cylindrical battery cell 100 may be formed by housing the electrode assembly 110 in the battery case 120, injecting an electrolyte into the battery case 120, and then combining the cap assembly 130 with the upper end of the battery case 120. The battery case 120 is cylindrical, and the wound roll-shaped electrode assembly 110 may be housed in the cylindrical battery case 120 to realize a cylindrical secondary battery.

[0048] The battery case 120 may include a bottom portion 121 disposed on a bottom side, a beading part 122 , and a clamping part 123 .

[0049] The beading portion 122 is used for stable connection of the cap assembly 130 and can be formed in the circumferential direction on the upper portion of the outer surface of the battery case 120 by being recessed toward the center of the electrode assembly 110 on the outer surface of the battery case 120. The beading portion 122 can prevent the electrode assembly 110 from moving.

[0050] The clamping portion 123 may be provided at an upper portion of the beading portion 122 and formed to cover an edge of the cap assembly 130 in a circumferential direction. The clamping portion 123 may ensure stable coupling of the cap assembly 130.

[0051] The cap assembly 130 may include a top cap 131 forming an anode terminal, a cap plate 132 to which an anode tab 134 extending upward from the electrode assembly 110 is connected, and a gasket 133 for maintaining sealing.

[0052] A gasket 133 may be installed on upper inner surfaces of the clamping portion 123 and the beading portion 122 to increase a sealing force between the cap assembly 130 and the battery case 120 .

[0053] As described above, the anode tab 134 may extend upward from the electrode assembly 110. Specifically, the anode tab 134 may extend from the negative electrode 111 of the electrode assembly 110.

[0054] The anode tab 134 is connected to the cap plate 132 , so the top cover 131 may function as an anode terminal. An opening 151 is formed in the upper insulating member 150 , and the anode tab 134 may pass through the opening 151 and be connected to the cap plate 132 .

[0055] The center pin 140 is generally made of a metal material to provide a specified strength and is formed into a cylindrical structure with a plate bent circularly. In addition to self-heating, the center pin 140 can serve as a channel for fixing and supporting the electrode assembly 110 and releasing gases generated by internal reactions during charge and discharge and operation.

[0056] The electrolyte injected into the battery case 120 can be a lithium salt-containing non-aqueous electrolyte, and the lithium salt-containing non-aqueous electrolyte is composed of a non-aqueous electrolyte and a lithium salt. Non-aqueous organic solvents, organic solid electrolytes, inorganic solid electrolytes, etc. can be used as non-aqueous electrolytes, but the present disclosure is not limited thereto.

[0057] The battery cells 100 applied to the thermal runaway test box 10 are not necessarily limited to cylindrical battery cells 100 . For example, can-shaped battery cells having a battery case in a rectangular parallelepiped shape or other shapes other than a cylindrical shape may be used to construct the thermal runaway test box 10 according to the present disclosure.

[0058] The box housing 200 of the thermal runaway test box 10 can accommodate a plurality of battery cells 100 . In this embodiment, the box housing 200 can be formed in a rectangular parallelepiped shape as shown in the figure. An insertion groove 211 can be formed in the upper plate 210 of the box housing 200 .

[0059] In the present embodiment, the cartridge case 200 may have a structure in which a plurality of battery cells 100 are vertically stacked.

[0060] In a structure in which the battery cell 100 is disposed at the top inside the cartridge case 200 , the battery cell 100 may be disposed between the battery cell bottom frame 250 and the battery cell top frame 270 .

[0061] The battery cell bottom frame 250 may be substantially square and include a plurality of battery cell insertion slots 251, and the battery cells 100 may be inserted into each of the battery cell insertion slots 251. The battery cell insertion slots 251 are formed in a circular shape, so that the circular battery cells 100 may be inserted therein. Figure 5 and Figure 6 As shown, the battery cells 100 may be inserted into the respective battery cell insertion grooves 251 such that the top cover 131 faces upward and the bottom 121 of the battery case 120 faces downward.

[0062] When the battery cells 100 are inserted into the battery cell bottom frame 250 , the battery cells 100 may be arranged to form a plurality of rows in the X-axis direction or the Y-axis direction of the cartridge case 200 .

[0063] The battery cell top frame 270 may be disposed on the battery cell 100 and cover an upper region of the battery cell, and may be combined with the battery cell bottom frame 250 .

[0064] For example, the battery cell top frame 270 may include a battery cell socket 271 vertically aligned with the battery cell insertion groove 251 of the battery cell bottom frame 250, and when the battery cell top frame 270 and the battery cell bottom frame 250 are combined, the top cover 131 of the battery cell 100 can be inserted into the battery cell socket 271, so that the upper area of ​​the battery cell 100 can be covered by the battery cell top frame 270.

[0065] In addition, a plurality of holes 272 are provided on the upper surface of the battery cell top frame 270, such as Figure 5 shown.

[0066] The hole 272 formed on the upper surface of the battery cell top frame 270 may be formed by partially penetrating the battery cell top frame 270 so that the top cover 131 of the battery cell 100 or the upper portion of the battery case 120 can be partially exposed to the outside.

[0067] The holes 272 may serve as passages that enable connection of the battery cells 100 with the bus bars 400 provided on the upper surface of the battery cell top frame 270 using metal wires.

[0068] The bus bar 400 may be connected to the top cover 131 of the battery cell 100 or the upper end of the battery case 120 exposed through the hole 272 using a metal wire. For example, a wire bonding method may be employed in which one end of the metal wire is welded to the top cover 131 or the upper end of the battery case 120 and the other end of the metal wire is welded to the bus bar 400.

[0069] In this embodiment, the structure in which the battery cells 100 are arranged at the bottom inside the box housing 200 can be realized by turning the structure in which the battery cells are arranged at the top upside down or arranging it into a vertically symmetrical structure.

[0070] Although similar to the above-mentioned structure in which the battery cell 100 is arranged at the top, in the structure in which the battery cell 100 is arranged at the bottom inside the box shell 200, the battery cell 100 can be arranged between the battery cell bottom frame 250 and the battery cell top frame 270, but the direction in which the battery cell 100 is arranged can be opposite to the above-mentioned structure in which the battery cell 100 is arranged at the top.

[0071] That is, the battery cell 100 may be disposed at the bottom of the interior of the box housing 200 such that the top cover 131 faces downward and the bottom 121 of the battery housing 120 faces upward. Therefore, the battery cell bottom frame 250 may be disposed above the bottom 121 of the battery housing 120 at the bottom of the interior of the box housing 200, and the battery cell top frame 270 may be disposed at the bottom of the top cover 131 of the battery cell 100. In addition, the battery cell 100 disposed at the bottom may not be aligned with the upper battery cell 100, and as Figure 6 As shown, one upper battery cell 100 may be provided across two battery cells 100 arranged at the bottom.

[0072] In the structure in which the battery cell 100 is arranged at the bottom inside the box shell 200, the battery cell bottom frame 250 can be arranged like the arrangement structure of the upper battery cell 100, including a plurality of battery cell insertion grooves 251, and the battery cell top frame 270 can include a battery cell recess 271, and the hole 272 and the bus bar 400 can also be arranged in the same manner.

[0073] The middle frame 300 may be provided between the upper and lower battery cells 100 in the cartridge case 200 , and the battery cell bottom frames 250 provided with the upper and lower battery cells 100 may be positioned facing each other at upper and lower sides of the middle frame 300 .

[0074] A battery thermal runaway test jig 1000 according to the present disclosure having the above-described structure and applied to the thermal runaway test box 10 will be described.

[0075] Figure 6 is a longitudinal sectional view showing a state in which the thermal runaway test jig according to the present disclosure is set in a thermal runaway test box, Figure 7 is a perspective view of a thermal runaway test fixture for a battery according to the present disclosure, Figure 8 yes Figure 7 A longitudinal cross-sectional view of a thermal runaway test fixture for a battery is shown in FIG. Figure 9 yes Figure 7 A detailed view of a thermal runaway test fixture for batteries is shown in FIG. Figure 10 yes Figure 7 FIGURE 1 shows the interior of a thermal runaway test fixture for a battery, and Figure 11 FIG. 1 is a diagram illustrating a state in which the thermal runaway test jig for a battery according to the present disclosure is used in a thermal runaway test box.

[0076] A thermal runaway test jig 1000 for a battery according to an embodiment of the present disclosure may include a nail assembly 1200 (nail module) to which a nail 1210 is coupled, and a nail holder 1100 supporting the nail assembly 1200 .

[0077] One or more nails 1210 may be coupled to the lower portion of the nail assembly 1200 , and for this purpose, a coupling groove 1220 to which the nail 1210 is coupled may be formed at the bottom of the nail assembly 1200 .

[0078] In addition, a plurality of nails 1210 may be coupled to the nail assembly 1200 , and a plurality of coupling grooves 1220 to which the plurality of nails 1210 are coupled may be formed at the bottom of the nail assembly 1200 .

[0079] Figures 6 to 11 An example is shown in which two coupling grooves 1220 are formed at the bottom of the nail assembly 1200 and the nail 1210 is coupled to the two coupling grooves 1220 .

[0080] An upper coupling groove 1230 may be formed at the top of the nail assembly 1200 , and the pressing rod 1300 may be coupled to the upper coupling groove 1230 .

[0081] Compression rod 1300 may be detachably coupled to the top of staple assembly 1200 so that compression rod 1300 may be replaceable.

[0082] The pressing rod 1300 may be pressed from the outside of the thermal runaway test box 10 to move the nail assembly 1200 downward.

[0083] As shown in the figure, the pressure rod 1300 can be arranged to extend outward through the insertion slot 211 of the upper plate 210 when the thermal runaway test fixture 1000 of the present disclosure is set in the thermal runaway test box 10. Therefore, the battery cell 100 can be destroyed by pressing the pressure rod 1300 from the outside of the thermal runaway test box 10.

[0084] The nail 1210 is used to destroy the battery cell 100 and may be vertically disposed at the bottom of the nail assembly 1200 , a body of the nail 1210 may vertically extend in a cylindrical shape, and a lower end of the nail 1210 may be formed in a tapered shape.

[0085] The nail 1210 is detachably coupled to a coupling groove 1220 formed at the bottom of the nail assembly 1200 so that the nail 1210 can be replaced, and a lower end of the nail 1210 is formed in a tapered shape so that the bottom of the battery cell 100 is easily broken.

[0086] As shown, staples 1210 and staple assembly 1200 can be housed within staple retainer 1100 .

[0087] The staple holder 1100 is used to accommodate and support the staples 1210 and the staple assembly 1200 , and in the present embodiment, the main body of the staple holder 1100 is formed in a generally cylindrical shape.

[0088] Specifically, the nail holder 1100 includes an insertion groove 1110 into which the nail assembly 1200 is inserted.

[0089] The insertion slot 1110 is formed by extending a prescribed length downward from the top of the nail holder 1100, and the nail assembly 1200 to which the nail 1210 is coupled can move up and down within the insertion slot 1110 after being inserted into the insertion slot 1110. Therefore, the vertical length of the insertion slot 1110 can be greater than the vertical length of the nail assembly 1200.

[0090] Insertion groove 1110 may be formed to correspond to nail assembly 1200. Therefore, the inner surface of insertion groove 1110 may include a pair of first inner wall surfaces 1110a and a pair of second inner wall surfaces 1110b facing each other to correspond to nail assembly 1200. Second inner wall surface 1110b may connect the pair of first inner wall surfaces 1110a to each other. In this embodiment, first inner wall surface 1110a may be formed as a flat surface, and second inner wall surface 1110b may be formed as a circular cross-section with an arc shape.

[0091] A bottom 1111 of the insertion groove 1110 may be located a prescribed distance upward from the bottom of the nail holder 1100 , and a passage hole 1120 may be formed at the bottom of the insertion groove 1110 .

[0092] The passage hole 1120 extends from the bottom 1111 of the insertion groove 1110 to the bottom of the nail holder 1100 , and the bottom 1111 of the insertion groove 1110 is connected to the outside through the passage hole 1120 .

[0093] In addition, the nails 1210 may move downward from the nail holder 1100 through the channel holes 1120 to destroy the battery cells 100 .

[0094] A pair of upwardly protruding upper protrusions 1130 may be formed on the nail holder 1100. The upper protrusions 1130 may be formed to extend upward from the pair of first inner wall surfaces 1110a and may be provided on both sides of the nail assembly 1200. The upper protrusions 1130 may guide the insertion and vertical movement of the nail assembly 1200.

[0095] In addition, when the thermal runaway test jig 1000 according to the present disclosure is set in the test box 10 , a tester may grip the upper protrusion 1130 to easily insert it into the battery cell insertion groove 251 of the test box 10 .

[0096] Next, we will refer to Figure 6 and Figure 11 A process of placing the thermal runaway test jig 1000 for a battery according to the present disclosure in the thermal runaway test box 10 and performing a thermal runaway (TP) test is described.

[0097] like Figure 6 As shown, a thermal runaway test jig 1000 is provided in one battery cell insertion groove 251 instead of a battery cell 100 in the thermal runaway test box 10, and the pressure rod 1300 is pressed downward in a state where it is coupled to the nail assembly 1200 through the insertion groove 211 formed in the upper plate 210 of the box housing 200 in the thermal runaway test box 10.

[0098] When the pressing rod 1300 is pressed downward, the nail assembly 1200 moves downward along the insertion slot 1110, and the downward movement of the nail assembly 1200 causes the nail 1210 to move downward through the channel hole 1120. The nail assembly 1200 can move downward until it contacts the bottom 1111 of the insertion slot 1110.

[0099] like Figure 11 As shown, the battery cells 100 disposed on the lower side are disposed opposite to the battery cells 100 disposed on the upper side, and the battery cells 100 disposed on the lower side may be disposed such that the top cover 131 faces downward and the bottom 121 of the battery case 120 faces upward.

[0100] Therefore, the bottom of the battery cell 100 may be broken by the nail 1210 moving downward.

[0101] Specifically, the nail 1210 can pierce the upper battery cell bottom frame 250, the middle frame 300 and the lower battery cell bottom frame 250 and move downward, and the tip 1211 of the nail 1210 can pierce the bottom of the battery cell 100 located therebelow and enter the interior of the battery cell 100.

[0102] As shown in the figures, in this embodiment, two nails 1210 provided at the bottom of the nail assembly 1200 can pierce the bottoms of two adjacent battery cells 100 .

[0103] The thermal runaway test fixture 1000 of the present disclosure is configured as described above to improve the accuracy and safety of thermal runaway testing.

[0104] In particular, in the present disclosure, the battery cell 100 to be destroyed and the nail 1210 can be accurately aligned, and the battery cell 100 can be destroyed at an accurate position.

[0105] In addition, in the present disclosure, a test failure due to bending of the nail 1210 does not occur, and a thermal propagation (TP) test may be performed on a plurality of battery cells as well as a single battery cell.

[0106] The present disclosure has been described with reference to the preferred embodiments as described above, but is not limited to the above embodiments, and those skilled in the art can make various changes and modifications within the scope not departing from the spirit of the present disclosure.

[0107] [Industrial Applicability]

[0108] The present disclosure can provide a thermal runaway test fixture for batteries that can improve the accuracy and safety of battery module stability assessment.

Claims

1. A thermal runaway test fixture for a battery, comprising: a nail assembly comprising nails at a lower portion; as well as A staple retainer is configured to accommodate the staple assembly.

2. The thermal runaway test fixture according to claim 1, wherein: The staples are detachably coupled to the staple assembly.

3. The thermal runaway test fixture according to claim 1, wherein: The nail assembly includes a coupling groove to which the nail is coupled.

4. The thermal runaway test fixture according to claim 1, wherein: The nail assembly includes a plurality of nails. The thermal runaway test fixture according to claim 1 , wherein the nail assembly further comprises a pressure rod.

6. The thermal runaway test fixture according to claim 5, wherein: The nail assembly includes an upper coupling groove, and the pressure rod is coupled to the upper coupling groove.

7. The thermal runaway test fixture according to claim 1, wherein: The nail holder includes an insertion slot into which the nail assembly is inserted.

8. The thermal runaway test fixture according to claim 7, wherein: The nail assembly is configured to be movable up and down within the insertion slot.

9. The thermal runaway test fixture according to claim 7, wherein: The bottom of the insertion groove is configured to be spaced apart from the lower end of the nail holder.

10. The thermal runaway test fixture according to claim 7, wherein: The nail holder further includes a passage hole on a lower side of the insertion slot for the nail to pass through.

11. The thermal runaway test fixture according to claim 10, wherein: The passage hole extends from the bottom of the insertion slot to the lower end of the nail holder.

12. The thermal runaway test fixture according to claim 10, wherein: The lower portion of the nail holder is provided with a plurality of passage holes for allowing the plurality of nails to pass through respectively.

13. The thermal runaway test fixture according to claim 7, wherein: The nail holder further includes a pair of upper protrusions protruding upward at an upper portion of the nail holder.

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