Battery pack

Abstract

The present invention relates to a battery pack for accommodating a plurality of cell assemblies, the battery pack being characterized by comprising: a battery pack housing in which the cell assemblies are arranged; an upper case coupled to the battery pack case to cover an upper portion of a cell assembly disposed inside the battery pack case; and at least one sparkproof member including a circular mesh and provided at a lower end of the upper case, in which the pack case includes at least one discharge hole in a side portion thereof communicating with an internal space, the sparkproof member is provided at a position corresponding to the discharge hole of the pack case, and the sparkproof member includes a circular mesh and is provided at a lower end of the upper case. The mesh holes have an average diameter of 0.1 mm to 0.5 mm.

Description

Technical Field

[0001] The present disclosure relates to a battery pack, characterized in that the battery pack includes a battery pack case and an upper case, the battery pack case includes at least one discharge hole, and the upper case has a spark preventing member with a mesh structure corresponding to the discharge hole.

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0117979, filed on September 5, 2023, the disclosure of which is incorporated herein by reference. Background Art

[0003] Lithium secondary batteries are typically in the form of batteries, which basically consist of an electrode assembly consisting of alternating electrodes and separators, electrode leads connected to the electrodes, and a casing that surrounds and seals the electrode assembly, allowing the electrode leads to extend outward. Depending on the shape of the electrode assembly and casing, these batteries can be categorized into cylindrical, prismatic, and pouch-type cells.

[0004] The output of a single battery cell is not large, so when used in a vehicle, multiple battery cells are connected to obtain the desired output.

[0005] Figure 1 A conventional battery pack 10 is shown having a cell assembly A' including a plurality of battery cells C' stacked and coupled together, and accommodating the cell assembly A' therein.

[0006] Typically, the battery pack 10 includes a battery pack housing 30 and an upper housing 20. A battery cell assembly A' is placed in the battery pack housing 30. Figure 1 As shown, the upper case 20 is coupled to the battery pack case 30 to cover the upper portion of the seated battery cell assembly A′.

[0007] Electric vehicles can be equipped with Figure 1 The battery pack 10 is shown, and an electric vehicle equipped with the battery pack 10 can obtain a large power output from the plurality of cell assemblies A′ included in one battery pack 10 .

[0008] As described above, battery packs 10 capable of achieving high power output present risks such as explosion and fire due to heat generation. Therefore, in addition to energy efficiency, ensuring safety is one of the key tasks of battery packs 10 used in electric vehicles and the like. If such abnormalities are not appropriately addressed at an early stage, the internal temperature of the battery pack 10 may rise sharply due to heat generation, and this temperature increase may cause the battery cells C' to experience thermal runaway.

[0009] To improve the safety of various electrical appliances, including electric vehicles, countries are requiring secondary battery manufacturers to meet several safety requirements. For example, China has proposed the GB 38031-2020 remedial measure, which requires the introduction of a system that can control thermal runaway of battery cell C' within 5 minutes.

[0010] China, as well as many other countries, require that the battery pack 10 be configured to effectively control abnormalities in the housed battery cells C′ before they develop into explosions and fires in the battery pack 10 .

[0011] Furthermore, when examining the thermal runaway process of cell assembly A', high-temperature gases generated by the vaporization of the electrolyte are released within cell assembly A', generating spark particles due to, for example, electrode short circuits. As mentioned above, to prevent a sharp rise in internal pressure due to high-temperature gases, conventional battery packs 10 are provided with a gas discharge path on one side that allows gas to be discharged. However, if the generated spark particles escape through the gas discharge path into an external, oxygen-rich environment, there is a risk of explosion.

[0012] Therefore, it is necessary to develop a battery pack 10 having a structure capable of selectively discharging only gas while suppressing the discharge of spark particles when a thermal runaway condition occurs inside a battery cell C′. Summary of the Invention

[0013] Technical issues

[0014] Therefore, the present disclosure has been conceived to solve the above-mentioned problems, and aims to provide a battery pack having a structure capable of selectively releasing only high-temperature gas in a thermal runaway condition.

[0015] Other purposes and advantages of the present disclosure will be understood from the following description and will become more apparent from the embodiments of the present disclosure. It is also obvious that the purposes and advantages of the present disclosure can be achieved by the devices disclosed in the patent claims and their combinations.

[0016] Technical Solution

[0017] The present disclosure provides a battery pack accommodating a plurality of battery cell assemblies.

[0018] The battery pack includes: a battery pack shell, in which a battery cell assembly is disposed; an upper shell, which is connected to the battery pack shell to cover the upper portion of the battery cell assembly disposed inside the battery pack shell; and at least one spark prevention component, the spark prevention component including a circular mesh and arranged at the lower end of the upper shell, wherein the battery pack shell includes at least one discharge hole on a side connected to the internal space, the spark prevention component is arranged at a position corresponding to the discharge hole of the battery pack shell, and the mesh has an average diameter of 0.1 mm to 0.43 mm.

[0019] The spark preventing member may have a mesh structure.

[0020] The average diameter of the mesh openings may be 0.35 mm to 0.43 mm.

[0021] The spark preventing member may stand perpendicular to the upper case such that the mesh holes communicate with the discharge hole of the pack case.

[0022] The battery pack case may include: a bottom plate that supports the lower portion of the battery cell assembly; a center beam that passes through a center portion of the bottom plate and is connected to the bottom plate so as to divide the internal space of the battery pack case into two; and side beams that are connected to edges of the bottom plate to support the sides of the battery cell assembly.

[0023] The battery pack case includes two drain holes, wherein each drain hole may be formed in the side wall to communicate with a corresponding battery pack case inner space partitioned by the center beam.

[0024] The spark prevention member may be located on at least one of the interior and exterior of the side wall.

[0025] A pair of spark preventing members is provided corresponding to one discharge hole, wherein

[0026] A pair of spark preventing members may be spaced apart by a predetermined distance and may be provided at a lower end of the upper case to face each other.

[0027] One of the pair of spark prevention members may be located inside the side wall, and the other may be located outside the side wall.

[0028] The side wall includes an insertion groove opened toward the upper portion for inserting the spark preventing member, the insertion groove corresponding to a position where the discharge hole is formed to intersect with the discharge hole, wherein the upper case can be coupled to the battery pack case by allowing the spark preventing member to be inserted into the insertion groove.

[0029] The spark preventing member may be provided at a lower end of the upper case at a position horizontally spaced a predetermined distance from the side wall.

[0030] The spark preventing member may be provided to be spaced apart from the side wall by 0.1 mm to 1 mm.

[0031] The spark protection member may comprise an electrically insulating material.

[0032] The spark protection member may comprise a flame retardant material.

[0033] The spark preventing member may have an area larger than that of the discharge hole.

[0034] Beneficial effects

[0035] According to the present disclosure, explosion and fire in a battery pack can be prevented in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A conventional battery pack and a cell assembly housed in the battery pack are shown.

[0037] Figure 2 is a front perspective view of a battery pack according to a first embodiment of the present disclosure.

[0038] Figure 3 yes Figure 2 Rear perspective view of the battery pack.

[0039] Figure 4 It is a front view of the spark protection component.

[0040] Figure 5 It is a bottom perspective view of the spark-proof component.

[0041] Figure 6 The process of coupling the upper case and the battery pack case together is shown.

[0042] Figure 7 yes Figure 6 A cross-sectional view of a battery pack showing the battery pack housing where the drain hole is located and the upper housing where the spark preventing member is located.

[0043] Figure 8 It is shown that the gas generated inside the battery pack is discharged to the outside through the discharge hole.

[0044] Figure 9 Shows the movement of spark particles generated inside a battery pack.

[0045] Figure 10 A process of coupling an upper case and a pack case included in a battery pack according to a second embodiment of the present disclosure is illustrated.

[0046] Figure 11 yes Figure 10 A cross-sectional view of a battery pack showing the battery pack housing where the drain hole is located and the upper housing where the spark preventing member is located.

[0047] Figure 12 A process of coupling an upper case and a pack case included in a battery pack according to a third embodiment of the present disclosure is illustrated.

[0048] Figure 13 yes Figure 12 A cross-sectional view of a battery pack showing the battery pack housing where the drain hole is located and the upper housing where the spark preventing member is located.

[0049] Figure 14 A process of coupling an upper case and a pack case included in a battery pack according to a fourth embodiment of the present disclosure is illustrated.

[0050] Figure 15 yes Figure 14 A cross-sectional view of a battery pack showing the battery pack housing where the drain hole is located and the upper housing where the spark preventing member is located.

[0051] Figure 16 Shown is the battery cell ignition equipment prepared for the experiment.

[0052] Figure 17 yes Figure 16 Cross-sectional view of the battery cell ignition device.

[0053] Figure 18 The experimental results of the first embodiment are shown.

[0054] Figure 19 The experimental results of Comparative Example 1 are shown.

[0055] Figure 20 The experimental results of Comparative Example 2 are shown. DETAILED DESCRIPTION

[0056] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Prior to this, it should be noted that the terms or words used in this specification and claims should not be interpreted with their ordinary meanings or dictionary meanings, but should be interpreted based on the concepts that the inventor can appropriately define the terms to best describe the principles of his / her disclosure in a sense and concept consistent with the technical idea of ​​the present disclosure.

[0057] Therefore, it should be understood that the embodiments described herein and the configurations shown in the drawings are merely the most preferred embodiments of the present disclosure and are not intended to exhaust the technical ideas of the present disclosure, and that various equivalents and modifications that can replace them may exist upon submission.

[0058] Furthermore, in describing the present disclosure, when it is determined that a detailed description of a related known configuration or feature would obscure the essence of the present disclosure, the detailed description is omitted.

[0059] Since the embodiments of the present disclosure are provided to more fully explain the present disclosure to those skilled in the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or schematically illustrated for the sake of clarity. Therefore, the size or ratio of each component does not necessarily indicate its actual size or ratio.

[0060] The present disclosure relates to a battery pack having a structure for accommodating a plurality of battery cell assemblies and capable of selectively releasing only high-temperature gas generated in a thermal runaway condition of the battery cells.

[0061] A battery pack of the present disclosure includes a pack case including at least one discharge hole and an upper case having a spark preventing member of a mesh structure corresponding to the discharge hole.

[0062] In particular, the battery pack of the present disclosure is characterized in that the mesh size in the spark preventing member is optimally restricted.

[0063] The battery cell assembly includes a plurality of battery cells stacked in one direction.

[0064] The battery cell includes an electrode assembly having alternately stacked electrodes and separators, electrode leads communicating with the electrodes, a battery cell case surrounding the electrode assembly to seal the electrode assembly, and an electrolyte filled in the battery cell case together with the electrode assembly.

[0065] The battery may include a pouch-type battery cell, a cylindrical battery cell, and a prismatic battery cell according to the shape of the cell case, and is not particularly limited by the present disclosure.

[0066] The battery cell assembly may further include a frame surrounding at least one side of the battery cell stack to protect the battery cell stack from external impacts and the like.

[0067] Figures 2 to 9 shows a battery pack according to a first embodiment of the present disclosure, Figures 10 and 11 shows a battery pack according to a second embodiment of the present disclosure, Figures 12 to 13 shows a battery pack according to a third embodiment of the present disclosure, Figures 14 and 15 shows a battery pack according to a fourth embodiment of the present disclosure, Figure 16 and Figure 17 The battery cell ignition device used in the experiments of the present disclosure is shown. Figures 18 to 20 Experimental results of examples and comparative examples are shown.

[0068] Hereinafter, specific embodiments of the battery pack of the present disclosure will be described in detail with reference to the accompanying drawings. For reference, unless otherwise defined, relative positioning names used in the following description (such as front to back or top to bottom) are intended to help understand the present disclosure and refer to the orientation shown in the accompanying drawings.

[0069] (First embodiment)

[0070] Figure 2 is a front perspective view of a battery pack according to a first embodiment of the present disclosure, and Figure 3 yes Figure 2 Rear perspective view of the battery pack.

[0071] The battery pack of the present disclosure includes a pack case 200 in which a cell assembly A is housed, and an upper case 100 coupled to the pack case 200 to cover an upper portion of the cell assembly A housed within the pack case 200 .

[0072] More specifically, the battery pack housing 200 includes a bottom plate 210 for supporting the lower portion of the battery cell assembly A, side beams 220 connected to the edges of the bottom plate 210 for supporting the sides of the battery cell assembly A, and a center beam 230 passing through the center portion of the bottom plate 210 and connected to the bottom plate 210 to divide the internal space of the battery pack housing 200 into two.

[0073] The battery pack housing 200 may further include a cross beam 240 coupled to the center beam 230 and the side beams 220 at both ends, respectively.

[0074] The cross beam 240 is used to further divide the interior space of the battery pack housing 200 partitioned by the central beam 230 into units of battery cell assemblies A. However, if desired, the cross beam 240 may not be included.

[0075] The internal space of the battery pack case 200 may be partitioned by the central beam 230 and the cross beam 240, etc., but each partitioned space may be interconnected. For example, if gas is generated from the battery cell assembly A stored in any of the above-mentioned partitioned spaces, the internal pressure of the internal space of the battery pack case 200 may be increased equally in any area.

[0076] The pack case 200 may include at least one exhaust hole 221 on a side portion communicating with the internal space. That is, the pack case 200 may be formed with the exhaust hole 221 on one side to allow internally generated gas (g) to be exhausted to the outside.

[0077] Specifically, if Figure 2 As shown, the exhaust hole 221 may be formed in the side member 220. Therefore, when one of the battery cell assemblies A experiences thermal runaway to generate high-temperature gas (g), the gas (g) may travel to the exhaust hole 221 and be discharged to the outside.

[0078] The battery pack case 200 of the present disclosure includes at least two drain holes 221 , each of which is formed in the side beam 220 to communicate with the corresponding inner space of the battery pack case 200 partitioned by the center beam 230 .

[0079] The discharge hole 221 may be formed on any one of the front and rear surfaces of the pack case 200 .

[0080] Refer to the above Figure 2 , two discharge holes 221 are formed on each side with respect to a coupling portion of the center beam 230 and the side beam 220 .

[0081] The upper case 100 is connected to the upper end of the side member 220 so that the inner space of the battery pack case 200 is sealed from the outside.

[0082] The battery pack of the present disclosure is characterized by further including a spark preventing member 300 provided at the lower end of the upper case 100 , the spark preventing member 300 selectively allowing only gas (g) to pass therethrough.

[0083] Figure 4 is a front view of the spark preventing member 300, Figure 5 It is a bottom perspective view of the spark preventing member 300 .

[0084] like Figure 4 As shown, the spark preventing member 300 has a mesh structure and includes a plurality of meshes 310 .

[0085] The mesh 310 of the spark preventing member 300 allows the gas (g) to pass therethrough and blocks the movement of spark particles (p) and the like.

[0086] The spark preventing member 300 preferably includes a flame retardant material so that it is not damaged by high temperature gas (g), etc. The spark preventing member 300 also preferably includes an insulating material so that current can be prevented from flowing through it.

[0087] The shape of the mesh 310 may be circular as shown in the figure, but is not limited thereto and may also be polygonal.

[0088] The spark preventing member 300 is connected at its upper end to the lower end of the upper housing 100. More specifically, as Figure 5 As shown, the spark preventing member 300 is vertically disposed to the upper housing 100. Thus, the gas (g) can travel in a horizontal direction and pass through the meshes 310 of the spark preventing member 300.

[0089] The battery pack of the present disclosure is characterized in that the spark preventing member 300 is provided at a position corresponding to the discharge hole 221 of the pack case 200 .

[0090] Figure 6 A process of coupling the upper case 100 and the pack case 200 together is shown.

[0091] Reference Figure 6, discharge holes 221 are formed in the side member 220 , and a spark preventing member 300 is provided at a lower end of the upper housing 100 at a position corresponding to each discharge hole 221 .

[0092] like Figure 6 As shown, the spark preventing member 300 included in the battery pack according to the first embodiment is provided at the lower end of the upper case 100 in such a manner as to be located inside the side member 220 .

[0093] The spark preventing member 300 coupled to the lower end of the upper case 100 standing vertically is shaped to cover the drain hole 221 when the upper case 100 is coupled to the battery pack case 200. That is, the spark preventing member 300 is shaped so that the mesh 310 communicates with the drain hole 221 of the battery pack case 200 when the upper case 100 and the battery pack case 200 are coupled to each other.

[0094] Figure 7 yes Figure 6 , a cross-sectional view of the battery pack, showing the battery pack case 200 where the discharge hole 221 is located and the upper case 100 where the spark preventing member 300 is located.

[0095] Preferably, the spark preventing member 300 has an area larger than that of the discharge hole 221 in order to intercept spark particles (p) sprayed toward the discharge hole 221 .

[0096] like Figure 7 As shown, the spark preventing member 300 is positioned to cover and close the entire discharge hole 221 .

[0097] However, the spark preventing member 300 is provided at a position spaced a predetermined distance apart so as not to contact the surface of the side member 220. That is, the spark preventing member 300 is provided at the lower end of the upper housing 100 at a position spaced a predetermined distance apart from the side member 220 in the horizontal direction.

[0098] Therefore, a gap Gp may be formed between the spark preventing member 300 and the side member 220 .

[0099] The gap Gp serves as an auxiliary travel path for the gas (g) exhausted through the mesh 310 to go directly to the discharge hole 221 without passing through the spark preventing member 300 .

[0100] In the event that a large amount of gas (g) is generated inside the battery pack, the gas (g) may not be discharged quickly through the mesh 310 of the spark preventing member 300. Therefore, in addition to the mesh 310, an additional path for the internal gas g to move toward the discharge hole 221 should be provided, wherein the gap Gp between the spark preventing member 300 and the side member 220 serves as the additional movement path.

[0101] The spacing of the gap Gp may vary depending on the expected amount of gas (g) and the pressure inside the battery pack.

[0102] Figure 8 It shows that the gas (g) generated inside the battery pack is discharged to the outside through the discharge hole 221. Figure 9 The migration of spark particles (p) generated inside the battery pack is shown.

[0103] according to Figure 8 , the gas (g) reaches the discharge hole 221 through the mesh 310 of the spark preventing member 300 , and also reaches the discharge hole 221 through the gap Gp between the spark preventing member 300 and the side member 220 .

[0104] according to Figure 9 , the spark particles (p) do not leave through the mesh 310 of the spark preventing member 300, but are blocked or deflected.

[0105] The size of the material that can pass through is limited by the size of the mesh 310, which has an average diameter d of 0.1 mm to 0.43 mm. In this case, if the average diameter (d) of the mesh 310 is less than 0.1 mm, the gas (g) will not be discharged as smoothly as expected, and there is a risk of explosion due to increased internal pressure of the battery pack. In addition, if the average diameter (d) of the mesh 310 is greater than 0.43 mm, there is a risk of spark particles (p) passing through.

[0106] More preferably, the mesh 310 has an average diameter (d) of 0.35 mm to 0.43 mm. The range of the mesh 310 is an optimal range for preventing the movement of spark particles (p) while allowing the gas (g) to be discharged most smoothly.

[0107] Therefore, even if thermal runaway occurs in any of the battery cell assemblies A contained therein and high-temperature gas (g) and spark particles (p) are generated, the battery pack disclosed herein can quickly discharge the high-temperature gas (g) to the outside, thereby minimizing the contact between the spark particles (p) and oxygen from the outside.

[0108] (Second embodiment)

[0109] The battery pack of the present disclosure allows for more variable positioning of the side sills 220 and the spark prevention member 300 .

[0110] Figure 10 shows a coupling process of the upper case 100 and the pack case 200 included in the battery pack according to the second embodiment of the present disclosure, and Figure 11 Shown Figure 10 sectional view of the battery pack housing 200 where the discharge hole 221 is located and the upper housing 100 where the spark preventing member 300 is located.

[0111] The spark preventing member 300 is provided at the lower end of the upper housing 100 such that it is located outside the side member 220 .

[0112] In this case, the spark particles (p) discharged through the discharge hole 221 without any resistance are captured by the spark preventing member 300 located outside the discharge hole 221 and prevented from escaping to the outside.

[0113] However, the gas (g) may be freely discharged through the gap Gp between the outer surface of the side member 220 and the spark preventing member 300 .

[0114] In the battery pack of the second embodiment of the present disclosure, as in the first embodiment, the size of the material that can pass through is limited by the size of the mesh 310, which has an average diameter (d) of 0.1 mm to 0.43 mm. In this case, if the average diameter (d) of the mesh 310 is less than 0.1 mm, the gas (g) will not be discharged as smoothly as expected, and there is a risk of explosion due to increased internal pressure of the battery pack. In addition, if the average diameter (d) of the mesh 310 is greater than 0.43 mm, there is a risk of spark particles (p) passing through.

[0115] More preferably, the mesh 310 has an average diameter (d) of 0.35 mm to 0.43 mm.

[0116] (Third embodiment)

[0117] The battery pack of the present disclosure may have an insertion groove 222 formed in the side member 220 , into which the spark prevention member 300 may be inserted.

[0118] Figure 12 shows a coupling process of the upper case 100 and the pack case 200 included in the battery pack according to the third embodiment of the present disclosure, and Figure 13 Shown Figure 12 sectional view of the battery pack housing 200 where the discharge hole 221 is located and the upper housing 100 where the spark preventing member 300 is located.

[0119] Reference Figure 12 and Figure 13 The side member 220 includes an insertion groove 222 opened upward for inserting the spark preventing member 300 .

[0120] The upper case 100 is coupled with the pack case 200 by allowing the spark preventing member 300 to be inserted into the insertion groove 222. In this case, the spark preventing member 300 is preferably configured not to contact the side member 220 in which the insertion groove 222 is formed.

[0121] The insertion groove 222 is formed to intersect with the discharge hole 221 corresponding to a position where the discharge hole 221 is formed.

[0122] Therefore, movement of spark particles (p) passing through the discharge hole 221 may be restricted by the spark preventing member 300 inserted into the insertion groove 222 .

[0123] However, in the case of the gas (g), the gas can be freely discharged to the outside through the gap Gp between the insertion groove 222 and the spark preventing member 300 and through the mesh 310 of the spark preventing member 300 .

[0124] In the battery pack of the present disclosure according to the third embodiment, as in the first embodiment, the size of the material that can pass through is limited by the size of the mesh 310, wherein the mesh 310 has an average diameter (d) of 0.1 mm to 0.43 mm. In this case, if the average diameter (d) of the mesh 310 is less than 0.1 mm, the gas (g) will not be discharged as smoothly as expected, and there is a risk of explosion due to the increase in internal pressure of the battery pack. In addition, if the average diameter (d) of the mesh 310 is greater than 0.43 mm, there is a risk of spark particles (p) passing through.

[0125] More preferably, the mesh 310 has an average diameter (d) of 0.35 mm to 0.43 mm.

[0126] (Fourth embodiment)

[0127] The battery pack of the present disclosure may have a dual-design spark prevention member 300 in one discharge hole 221 .

[0128] Figure 14 shows a coupling process of the upper case 100 and the pack case 200 included in the battery pack according to the fourth embodiment of the present disclosure, and Figure 15 Shown in Figure 14 sectional view of the battery pack, wherein the discharge hole 221 is located in the battery pack case 200 and the spark preventing member 300 is located in the upper case 100.

[0129] like Figure 14 and Figure 15 As shown, one discharge hole 221 is opposed by a pair of spark preventing members 300 .

[0130] A pair of spark preventing members 300 are spaced apart by a predetermined distance and are provided at the lower end of the upper housing 100 in such a manner as to face each other.

[0131] Specifically, one of the pair of spark preventing members 300 is located inside the side member 220, and the other is located outside the side member 220. Preferably, each of the pair of spark preventing members 300 is arranged so as not to contact the side member 220.

[0132] Thus, spark particles (p) generated inside the battery pack are restricted from traveling to the outside by the pair of double-designed spark preventing members 300 .

[0133] Specifically, the movement of the gas (g) generated inside the battery pack may be restricted primarily by the spark preventing member 300 located inside the pack case 200 and secondarily by the spark preventing member 300 located outside the pack case 200 .

[0134] However, the gas (g) generated inside the battery pack may be discharged to the outside through the meshes 310 formed in each spark preventing member 300 , or may be supplementarily discharged to the outside through the gap Gp between each spark preventing member 300 and the side member 220 .

[0135] In the battery pack of the present disclosure according to the fourth embodiment, as in the first embodiment, the size of the material that can pass through is limited by the size of the mesh 310, which has an average diameter (d) of 0.1 mm to 0.43 mm. In this case, if the average diameter (d) of the mesh 310 is less than 0.1 mm, the gas (g) will not be discharged as smoothly as expected, and there is a risk of explosion due to increased internal pressure of the battery pack. In addition, if the average diameter (d) of the mesh 310 is greater than 0.43 mm, there is a risk of spark particles (p) passing through.

[0136] More preferably, the mesh 310 has an average diameter (d) of 0.35 mm to 0.43 mm.

[0137] Hereinafter, the present disclosure will be described in more detail with reference to specific examples. However, these examples are intended to illustrate the present disclosure, and the scope of the present disclosure is not limited thereto.

[0138] Preparation of battery cell ignition equipment (E)

[0139] Figure 16 A cell ignition device E is shown which is intended to intentionally generate thermal runaway in the cell C to generate a spark, and Figure 17 Shown Figure 16 Cross-sectional view of the battery cell ignition device E.

[0140] According to the battery cell ignition device E, it is in the form of a box with holes on both sides, and the battery cell C for the experiment and the heating pad Ph for igniting the battery cell C are placed inside the box. Figure 16 As shown, partition walls W including spark preventing members 300 are installed on both sides of the battery cell C. Therefore, the battery cell C and the heating pad Ph used in the experiment are isolated from contact with the outside by the partition walls W except for the spark preventing member 300.

[0141] In addition, in the battery cell ignition device E, a tempered glass Gs is installed at the upper portion of the coupling partition wall W to check the generation and movement of sparks.

[0142] The cell ignition device E simulates a battery pack environment, wherein the partition wall W corresponds to the side member 220 of the battery pack.

[0143] like Figure 17 As shown, the cell ignition device E may be divided into an outlet space communicating with the outside and an inlet space being a space between a pair of partition walls W.

[0144] according to Figure 17 A pair of pouch-type cells C are stacked side by side in the inlet space, with a heating pad Ph capable of heating to 200°C or higher interposed between the cells C. The cells C include an electrode assembly comprising 40 stacked unit cells C of a separator-negative electrode-separator-positive electrode-separator stack.

[0145] The top of the stacked cell C is as follows Figure 17 The stacked cells C are shown supported by an upper jig G1 and supported by a lower jig G2. Although not shown, the upper jig G1 and the lower jig G2 are bolted to each other, and the battery cells C are compressed by tightening the bolts.

[0146] Example 1

[0147] exist Figure 16 In the battery cell ignition device E, the spark preventing member 300 having a mesh 310 size of 0.43 mm is applied.

[0148] Example 2

[0149] exist Figure 16 In the battery cell ignition device E, the spark preventing member 300 having a mesh 310 size of 0.41 mm is applied.

[0150] Example 3

[0151] exist Figure 16 In the battery cell ignition device E, the spark preventing member 300 having a mesh 310 size of 0.35 mm is applied.

[0152] Comparative Example 1

[0153] exist Figure 16 In the battery cell ignition device E, the spark preventing member 300 having a mesh 310 size of 0.6 mm is applied.

[0154] Comparative Example 2

[0155] exist Figure 16In the battery cell ignition device E, the spark preventing member 300 having a mesh 310 size of 0.5 mm is applied.

[0156] Comparative Example 3

[0157] exist Figure 16 In the battery cell ignition device E, the spark preventing member 300 having a mesh 310 size of 0.48 mm is applied.

[0158] Experimental example

[0159] The heating pad Ph of each battery cell ignition device E prepared in Examples 1-3 and Comparative Examples 1-3 was activated, and the temperature of the heating pad Ph was raised to a point where sparks were generated in the battery cells C contained therein. Each battery cell C was then ignited until the sparks were observed from the outside through the mesh 310 of each spark prevention member 300. The time from spark generation in each battery cell C contained in the inlet space to the time when spark particles (p) were ejected into the outlet space of the device was measured and is shown in Table 1 below.

[0160] [Table 1]

[0161] Spark injection time (seconds) Example 1 Not observable Example 2 Not observable Example 3 Not observable Comparative Example 1 2 Comparative Example 2 4 Comparative Example 3 17

[0162] Figure 18 This is a photograph of the area where the spark preventing member 300 is located when sparks are generated in the battery cell C of the battery cell ignition device E of Example 1. Figure 18 It can be seen that the sparks generated in the inlet space will not be discharged to the outlet space through the spark preventing component 300.

[0163] The same features are observed in Examples 2 and 3.

[0164] However, in the case of Comparative Example 1, the spark particles (p) are released to the outside through the mesh 310 in a relatively short time after sparks are generated in the battery cell C. Figure 19 This is a photograph of the area where the spark preventing member 300 is located when sparks are generated in the battery cell C of the battery cell ignition device E of Comparative Example 1.

[0165] Reference Figure 19 , the sparks generated in the inlet space pass through the partition wall W and are observed at the outlet space.

[0166] In the case of Comparative Example 2, the release time of the spark particles (p) was relatively long compared to Comparative Example 1, but sparks were observed in the outlet space, and further, explosion caused by the sparks was temporarily observed. Figure 20 This is a photograph of the area where the spark preventing member 300 is located when sparks are generated in the battery cell C of the battery cell ignition device E of Comparative Example 2. Figure 20, flames caused by the explosion were observed in the exit space.

[0167] In the case of Comparative Example 3, it took the longest time for the spark to be detected in the outlet space, indicating that it has some effectiveness in delaying the explosion. However, like Comparative Examples 1 and 2, Comparative Example 3 also produced a large flame after a period of time.

[0168] The present disclosure has been described in more detail above with reference to the accompanying drawings and embodiments. However, it should be understood that the configuration shown in the drawings or the embodiments described herein is only one embodiment of the present invention and does not represent the entire technical concept of the present invention, and various equivalents and modifications that can replace them when filing this application may exist.

[0169] [Explanation of Reference Signs]

[0170] 10: (Prior Art) Battery Pack

[0171] 20: (Prior art) upper shell

[0172] 30: (Prior Art) Battery Pack Housing

[0173] A': (Prior Art) Cell Assembly

[0174] C': (Prior Art) Cell

[0175] 100: Upper shell

[0176] 200: Battery pack housing

[0177] 210: Base plate

[0178] 220: Side beam

[0179] 221: Drain hole

[0180] 222: Insert slot

[0181] 230: Center beam

[0182] 240: beam

[0183] 300: Anti-spark components

[0184] 310: Mesh

[0185] A: Battery cell components

[0186] C: Battery

[0187] E: Battery ignition equipment

[0188] G1: Upper fixture

[0189] G2: Lower fixture

[0190] Gs: Tempered glass

[0191] Ph: Heating Pad

[0192] W: dividing wall

[0193] g:gas (motion)

[0194] p: spark particles (motion)

[0195] Gp: gap (interval)

[0196] d: mesh (average) diameter

Claims

1. A battery pack accommodating a plurality of battery cell assemblies, the battery pack comprising: A battery pack housing, wherein the battery pack housing houses the battery cell assembly; an upper housing coupled to the battery pack housing to cover an upper portion of the battery cell assembly disposed within the battery pack housing; and at least one spark preventing member including circular meshes and provided at a lower end of the upper housing, The battery pack housing includes at least one discharge hole on the side thereof, which is connected to the internal space. The spark preventing member is provided at a position corresponding to the discharge hole of the battery pack case, and The average diameter of the mesh is 0.1 mm to 0.43 mm.

2. The battery pack according to claim 1, wherein: The spark preventing member has a mesh structure.

3. The battery pack according to claim 1, wherein: The average diameter of the mesh is 0.35 mm to 0.43 mm.

4. The battery pack according to claim 1, wherein The spark preventing member stands perpendicular to the upper case so that the mesh holes communicate with the discharge hole of the pack case.

5. The battery pack according to claim 1, wherein The battery pack housing comprises: a bottom plate supporting the lower portion of the battery cell assembly; a center beam passing through a center portion of the bottom plate and coupled to the bottom plate so as to divide an inner space of the battery pack case into two; and A side beam is coupled to an edge of the bottom plate to support a side of the battery cell assembly.

6. The battery pack according to claim 5, wherein: The battery pack housing includes two drain holes, Each of the discharge holes is formed in the side wall to communicate with an inner space of a corresponding battery pack housing partitioned by the center beam.

7. The battery pack according to claim 5, wherein: The spark prevention member is located on at least one of the interior and exterior of the side wall.

8. The battery pack according to claim 5, wherein: A pair of spark preventing members is provided corresponding to each of the discharge holes. The pair of spark preventing members are spaced apart by a predetermined distance and are disposed at the lower end of the upper housing so as to face each other.

9. The battery pack according to claim 8, wherein: One of the pair of spark preventing members is located inside the side wall, and the other is located outside the side wall.

10. The battery pack according to claim 5, wherein: The side wall includes an insertion groove opened upward for inserting the spark preventing member. The insertion groove is formed to intersect with the discharge hole corresponding to the position where the discharge hole is formed. wherein the upper case is coupled to the battery pack case by allowing the spark preventing member to be inserted into the insertion groove.

11. The battery pack according to claim 5, wherein: The spark preventing member is provided at a lower end of the upper case at a position horizontally spaced apart from the side wall by a predetermined distance.

12. The battery pack according to claim 11, wherein: The spark preventing member is provided to be spaced apart from the side wall by 0.1 mm to 1 mm.

13. The battery pack according to claim 1, wherein The spark protection member comprises an electrically insulating material.

14. The battery pack according to claim 1, wherein The spark preventing member comprises a flame retardant material.

15. The battery pack according to claim 1, wherein The spark preventing member has an area larger than an area of ​​the discharge hole.

Images