Battery pack

Abstract

The present invention relates to a battery pack accommodating a plurality of cell assemblies, comprising: a pack case in which the cell assemblies are mounted; an upper case coupled to the pack case so as to cover an upper portion of the cell assemblies mounted inside the pack case; and at least one spark prevention member having a circular mesh hole and provided at a lower end of the upper case, wherein at least one exhaust hole communicating with an internal space is provided in a side wall of the pack case, the spark prevention member is provided at a position corresponding to the exhaust hole of the pack case, and the mesh hole has an average diameter of 0.1 mm to 0.5 mm.

Description

[Technical Field]

[0001] The present invention relates to a battery pack, and the battery pack of the present invention is characterized by including a pack case including at least one exhaust hole, and an upper case provided with a spark prevention member having a mesh structure corresponding to the exhaust hole.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0117979, filed September 5, 2023, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Lithium secondary batteries are typically in the form of a cell, which includes an electrode assembly in which electrodes and separators are alternately stacked, electrode leads connected to the electrodes, and a case that encloses and seals the electrode assembly so that the electrode leads extend to the outside. Depending on the shape of the electrode assembly and the case, lithium secondary batteries can be classified into cylindrical cells, prismatic cells, pouch cells, etc.

[0004] The output generated by one cell is not large, so when applied to vehicles, multiple cells are connected together to obtain the desired output.

[0005] FIG. 1 shows a cell assembly A' in which a plurality of cells C' are stacked and joined together, and a conventional battery pack 10 in which the cell assembly A' is housed.

[0006] Generally, as shown in FIG. 1, the battery pack 10 is composed of a pack case 30 in which a cell assembly A' is installed, and an upper case 20 that is coupled to the pack case 30 so as to cover the top of the installed cell assembly A'.

[0007] The battery pack 10 shown in FIG. 1 can be installed in an electric vehicle, and the electric vehicle equipped with the battery pack 10 can obtain a large output due to the multiple cell assemblies A' included in the single battery pack 10.

[0008] The battery pack 10, which can obtain a large output as described above, is susceptible to explosions, fires, and the like due to heat generation. Therefore, ensuring safety as well as energy efficiency is an important issue for the battery pack 10 used in electric vehicles, etc. If an appropriate response is not made in the early stages when such an abnormal phenomenon occurs, the internal temperature of the battery pack 10 may rise rapidly due to heat generation, and the temperature increase may cause thermal runaway in the cell C'.

[0009] Each country requires secondary battery manufacturers to comply with certain safety requirements in order to improve the safety of various electrical products, including electric vehicles. For example, China has proposed a relief plan for GB 38031-2020, which requires manufacturers to implement a system that can control thermal runaway of cell C' within five minutes of its occurrence.

[0010] Not only in China but in many other countries, there is a demand for a battery pack 10 that has a structure that can effectively control abnormal phenomena in cell C' before they develop into an explosion and fire in the battery pack 10.

[0011] Meanwhile, in the thermal runaway process of cell assembly A', high-temperature gas generated by the vaporization of the electrolyte inside cell assembly A' is released, and spark particles may be generated due to short circuits between electrodes. A typical battery pack 10 has a gas exhaust path on the side through which gas can be released to prevent a sudden increase in internal pressure due to the high-temperature gas. However, if the generated spark particles escape through the gas exhaust path into the outside where oxygen is concentrated, there is a risk of an explosion.

[0012] Therefore, there is a need to develop a battery pack 10 having a structure that can selectively discharge only gas while suppressing the discharge of spark particles when a thermal runaway condition occurs in the cell C' inside. Summary of the Invention [Problem to be solved by the invention]

[0013] Therefore, the present invention has been devised to solve the above problems, and an object of the present invention is to provide a battery pack having a structure that can selectively release only high-temperature gas in a thermal runaway situation.

[0014] Other objects and advantages of the present invention can be understood from the following description and become more apparent from the embodiments of the present invention, and it is easily understood that the objects and advantages of the present invention can be realized by the means and combinations thereof as set forth in the claims. [Means for solving the problem]

[0015] In accordance with the present invention, a battery pack is provided that contains a plurality of cell assemblies.

[0016] The battery pack includes a pack case in which a cell assembly is installed, an upper case coupled to the pack case to cover an upper portion of the cell assembly installed inside the pack case, and at least one spark prevention member having a circular mesh hole and provided at a lower end of the upper case, wherein at least one exhaust hole communicating with an internal space is provided in a side wall of the pack case, the spark prevention member is provided at a position corresponding to the exhaust hole of the pack case, and an average diameter of the mesh hole is 0.1 mm to 0.43 mm.

[0017] The spark arrestor may have a mesh structure.

[0018] The average diameter of the mesh holes may be 0.35 mm to 0.43 mm.

[0019] The spark prevention member may be provided standing vertically on the upper case so that mesh holes can communicate with the discharge holes of the pack case.

[0020] The pack case can include a base plate that supports the lower part of the cell assembly, a center beam that crosses the center of the base plate and is connected to the base plate so as to divide the internal space of the pack case into two, and side beams that are connected to the edges of the base plate so as to support the sides of the cell assembly.

[0021] The pack case may include two exhaust holes, each of which may be formed in the side wall to communicate with an internal space of the pack case defined by the center beam.

[0022] The spark prevention member may be located on at least one of the inside and outside of the sidewall.

[0023] a pair of spark prevention members corresponding to the at least one discharge hole; The pair of spark prevention members may be provided at the lower end of the upper case to face each other with a predetermined gap therebetween.

[0024] 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.

[0025] The sidewall may include an insertion groove that is open upward and into which the spark prevention member may be inserted, the insertion groove being formed in correspondence with a position where the exhaust hole is formed so as to intersect with the exhaust hole, and the upper case may be coupled to the pack case with the spark prevention member inserted into the insertion groove.

[0026] The spark prevention member may be installed at a lower end of the upper case at a position spaced a predetermined distance horizontally from the side wall.

[0027] The spark prevention member may be spaced apart from the sidewall by 0.1 mm to 1 mm.

[0028] The spark arrestor may include an electrically insulating material.

[0029] The spark arrestor may include a flame-resistant material.

[0030] The spark prevention member may have an area larger than an area of ​​the exhaust hole. [Effects of the Invention]

[0031] According to the present invention, it is possible to prevent the explosion of the battery pack and the occurrence of a fire. [Brief explanation of the drawings]

[0032] [Figure 1] 1 shows a conventional battery pack and a cell assembly contained in the battery pack. [Figure 2] 1 is a front perspective view of a battery pack according to a first embodiment of the present invention; [Figure 3] FIG. 3 shows a rear perspective view of the battery pack of FIG. 2. [Figure 4] FIG. 2 is a front view of the spark prevention member. [Figure 5] FIG. 2 is a bottom perspective view of the spark arrestor. [Figure 6] 10 shows the process of joining the upper case and the pack case. [Figure 7] 7 shows a cross section of a pack case where a discharge hole is located and an upper case where a spark prevention member is located in the battery pack of FIG. 6. [Figure 8]This indicates that gas generated inside the battery pack is discharged to the outside through the exhaust hole. [Figure 9] This shows the movement of spark particles generated inside the battery pack. [Figure 10] 10 illustrates a process of combining an upper case and a pack case included in a battery pack according to a second embodiment of the present invention. [Figure 11] 11 shows a cross section of the pack case where the discharge hole is located and the upper case where the spark prevention member is located in the battery pack of FIG. 10. [Figure 12] 10 illustrates a process of combining an upper case and a pack case included in a battery pack according to a third embodiment of the present invention. [Figure 13] 13 shows a cross section of the pack case where the exhaust hole is located and the upper case where the spark prevention member is located in the battery pack of FIG. 12. [Figure 14] 10 illustrates a process of combining an upper case and a pack case included in a battery pack according to a fourth embodiment of the present invention. [Figure 15] 15 shows a cross section of the pack case where the discharge hole is located and the upper case where the spark prevention member is located in the battery pack of FIG. 14. [Figure 16] This shows the cell firing equipment prepared for the experiment. [Figure 17] 17 shows a cross section of the cell firing device of FIG. 16. [Figure 18] 1 shows the experimental results of Example 1. [Figure 19] 1 shows the experimental results of Comparative Example 1. [Figure 20] 10 shows the experimental results of Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, it should be noted that the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe his / her own invention.

[0034] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0035] Furthermore, in the description of the present invention, if it is determined that a specific description of related publicly known configurations or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0036] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown schematically for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0037] The present invention relates to a battery pack that houses a plurality of cell assemblies and has a structure that can selectively release only high-temperature gas generated in the event of thermal runaway of the cells.

[0038] The battery pack of the present invention includes a pack case having at least one exhaust hole, and an upper case provided with a spark prevention member having a mesh structure corresponding to the exhaust hole.

[0039] In particular, the battery pack of the present invention is characterized in that the size of the mesh holes of the spark prevention member is optimally limited.

[0040] The cell assembly includes a plurality of cells stacked in one direction.

[0041] The cell includes an electrode assembly in which electrodes and separators are alternately stacked, electrode leads connected to the electrodes, a cell case that hermetically encloses the electrode assembly, and an electrolyte that is filled in the cell case together with the electrode assembly.

[0042] The cell may be a pouch-type cell, a cylindrical cell, or a prismatic cell depending on the shape of the cell case, and the present invention is not particularly limited thereto.

[0043] The cell assembly may further include a frame surrounding at least one side of the cell stack to protect the cell stack from external impacts.

[0044] 2 to 9 relate to a battery pack according to a first embodiment of the present invention, FIGS. 10 to 11 relate to a battery pack according to a second embodiment of the present invention, FIGS. 12 to 13 relate to a battery pack according to a third embodiment of the present invention, FIGS. 14 to 15 relate to a battery pack according to a fourth embodiment of the present invention, FIGS. 16 and 17 relate to cell ignition equipment used in experiments of the present invention, and FIGS. 18 to 20 relate to experimental results of examples and comparative examples.

[0045] Hereinafter, specific embodiments of the battery pack of the present invention will be described in detail with reference to the accompanying drawings. For reference, the directions of front, back, up, down, left, and right used in the following description to designate relative positions are intended to facilitate understanding of the invention, and unless otherwise specified, are based on the directions shown in the drawings.

[0046] (First embodiment) FIG. 2 is a front perspective view of the battery pack according to the first embodiment of the present invention, and FIG. 3 is a rear perspective view of the battery pack of FIG.

[0047] The battery pack of the present invention includes a pack case 200 in which a cell assembly A is installed, and an upper case 100 that is coupled to the pack case 200 so as to cover the upper part of the cell assembly A installed inside the pack case 200.

[0048] More specifically, the pack case 200 includes a base plate 210 that supports the lower part of the cell assembly A, side beams 220 that are connected to the edges of the base plate 210 to support the sides of the cell assembly A, and a center beam 230 that is connected to the base plate 210 across the center of the base plate 210 to divide the internal space of the pack case 200 into two.

[0049] In addition, the pack case 200 may further include a cross beam 240, both ends of which are connected to the center beam 230 and the side beams 220, respectively.

[0050] The cross beam 240 serves to re-divide the internal space of the pack case 200, which is divided by the center beam 230, into units of cell assemblies A. However, the cross beam 240 may be omitted if necessary.

[0051] The internal space of the pack case 200 may be partitioned by the center beam 230 and the cross beams 240, and the partitioned spaces may be substantially connected to each other. For example, when gas g is generated from a cell assembly A housed in one of the partitioned spaces, the internal pressure of the internal space of the pack case 200 may rise evenly in all regions.

[0052] At least one exhaust hole 221 communicating with the internal space is formed in a sidewall of the pack case 200. That is, the pack case 200 may have the exhaust hole 221 formed on one side thereof so that gas g generated inside can be exhausted to the outside.

[0053] Specifically, the exhaust hole 221 may be formed in the side beam 220 as shown in Fig. 2. Therefore, when any one of the cell assemblies A experiences thermal runaway and generates high-temperature gas g, the gas g can move to the exhaust hole 221 and be exhausted to the outside.

[0054] The pack case 200 of the present invention includes at least two or more discharge holes 221, and each discharge hole 221 is formed in the side beam 220 so as to communicate with the internal space of each pack case 200 partitioned by the center beam 230.

[0055] The discharge hole 221 may be formed on either the front or rear surface of the pack case 200 .

[0056] Referring to FIG. 2, two discharge holes 221 are formed on both sides of the joining portion between the center beam 230 and the side beams 220.

[0057] The upper case 100 is coupled to the upper end of the side beam 220 so that the inner space of the pack case 200 can be isolated from the outside.

[0058] The battery pack of the present invention is characterized in that it further includes a spark prevention member 300 provided at the lower end of the upper case 100 and selectively allowing only gas g to pass through.

[0059] FIG. 4 is a front view of spark arrestor 300, and FIG. 5 is a bottom perspective view of spark arrestor 300. As shown in FIG.

[0060] The spark arrestor 300 has a mesh structure and includes a plurality of mesh holes 310 as shown in FIG.

[0061] The mesh holes 310 of the spark prevention member 300 allow gas g to pass through and prevent the movement of spark particles p and the like.

[0062] The spark prevention member 300 preferably includes a flame-resistant material so as not to be damaged by high-temperature gas g, etc. Also, it preferably includes an electrically insulating material so as to be able to block the flow of electricity.

[0063] The shape of the mesh holes 310 may be circular as shown in the figure, but is not limited thereto and may be polygonal.

[0064] The upper end of the spark prevention member 300 is coupled to the lower end of the upper case 100. More specifically, the spark prevention member 300 is provided to stand vertically on the upper case 100 as shown in Fig. 5. Therefore, the gas g can pass through the mesh holes 310 of the spark prevention member 300 while moving in the horizontal direction.

[0065] The battery pack of the present invention is characterized in that the spark prevention member 300 is installed at a position corresponding to the exhaust hole 221 of the pack case 200.

[0066] FIG. 6 shows the process in which the upper case 100 and the pack case 200 are joined together.

[0067] Referring to FIG. 6, exhaust holes 221 are formed in the side beams 220, and the spark prevention members 300 are provided at the lower end of the upper case 100 at positions corresponding to the exhaust holes 221.

[0068] The spark prevention member 300 included in the battery pack according to the first embodiment is provided at the lower end of the upper case 100 so as to be located inside the side beam 220, as shown in FIG.

[0069] Spark prevention member 300, which is coupled to stand vertically at the lower end of upper case 100, is shaped to cover exhaust hole 221 when upper case 100 is coupled to pack case 200. That is, mesh hole 310 of spark prevention member 300 communicates with exhaust hole 221 of pack case 200 when upper case 100 and pack case 200 are coupled to each other.

[0070] FIG. 7 shows a cross section of the pack case 200 in which the discharge hole 221 is located and the upper case 100 in which the spark prevention member 300 is located in the battery pack of FIG.

[0071] The spark prevention member 300 preferably has an area larger than that of the discharge hole 221 so as to be able to block the spark particles p flying toward the discharge hole 221 .

[0072] As shown in FIG. 7, the spark prevention member 300 is provided at a position where it can cover and block the entire discharge hole 221.

[0073] However, the spark prevention member 300 is provided at a position spaced a predetermined distance from the surface of the side beam 220 so as not to come into contact with the surface of the side beam 220. That is, the spark prevention member 300 is provided at a position spaced a predetermined distance from the side beam 220 in the horizontal direction at the lower end of the upper case 100.

[0074] Therefore, a gap Gp may be formed between the spark prevention member 300 and the side beam 220.

[0075] The gap Gp serves as an auxiliary passage through which the gas g discharged through the mesh holes 310 travels directly to the discharge holes 221 without passing through the spark prevention member 300 .

[0076] When a large amount of gas g is generated inside the battery pack, it may be impossible to quickly exhaust the gas g through the mesh holes 310 of the spark prevention member 300. Therefore, in addition to the mesh holes 310, an additional path must be secured to allow the internal gas g to move to the exhaust holes 221, and the gap Gp between the spark prevention member 300 and the side beam 220 serves as the additional movement path.

[0077] The size of the gap Gp may vary depending on the expected amount of gas g and the pressure inside the battery pack.

[0078] FIG. 8 shows that gas g generated inside the battery pack is discharged to the outside through the discharge hole 221, and FIG. 9 shows the movement of spark particles p generated inside the battery pack.

[0079] Referring to FIG. 8, gas g can reach the exhaust hole 221 through the mesh hole 310 of the spark prevention member 300, or through the gap Gp between the spark prevention member 300 and the side beam 220.

[0080] According to FIG. 9 above, the spark particles p cannot exit through the mesh holes 310 of the spark prevention member 300, and are blocked or bounced back.

[0081] The size of the material that can pass through is limited depending on the size of the mesh holes 310, and the average diameter d of the mesh holes 310 is 0.1 mm to 0.43 mm. If the average diameter d of the mesh holes 310 is less than 0.1 mm, gas g may not be discharged as smoothly as desired, and there is a risk of explosion due to an increase in the internal pressure of the battery pack. Also, if the average diameter d of the mesh holes 310 is more than 0.43 mm, there is a risk of spark particles p passing through.

[0082] More preferably, the average diameter d of the mesh holes 310 is 0.35 mm to 0.43 mm. The range of the mesh holes 310 is an optimum range that can most smoothly discharge the gas g while blocking the movement of the spark particles p.

[0083] Therefore, even if a thermal runaway phenomenon occurs in any one of the cell assemblies A housed therein and high-temperature gas g and spark particles p are generated, the battery pack of the present invention can quickly discharge the high-temperature gas g to the outside and minimize contact of the spark particles p with external oxygen.

[0084] (Second embodiment) The battery pack of the present invention allows the positions of the side beams 220 and the spark prevention members 300 to be adjusted more variably.

[0085] FIG. 10 shows a process of combining an upper case 100 and a pack case 200 included in a battery pack according to a second embodiment of the present invention, and FIG. 11 shows a cross section of the pack case 200 where the discharge hole 221 is located and the upper case 100 where the spark prevention member 300 is located in the battery pack of FIG. 10.

[0086] The spark prevention member 300 is provided at the lower end of the upper case 100 so as to be located outside the side beam 220 .

[0087] In this case, the spark particles p that are emitted through the discharge holes 221 without any resistance are caught by the spark prevention member 300 located outside the discharge holes 221 and cannot escape to the outside.

[0088] However, the gas g can be smoothly discharged through the gap Gp between the outer surface of the side beam 220 and the spark prevention member 300.

[0089] In the battery pack according to the second embodiment of the present invention, as in the first embodiment, the size of the material that can pass through is limited depending on the size of the mesh holes 310, and the average diameter d of the mesh holes 310 is 0.1 mm to 0.43 mm. If the average diameter d of the mesh holes 310 is less than 0.1 mm, gas g may not be discharged as smoothly as desired, and an explosion may occur due to an increase in the internal pressure of the battery pack. Also, if the average diameter d of the mesh holes 310 exceeds 0.43 mm, there is a risk that spark particles p may pass through.

[0090] More preferably, the average diameter d of the mesh holes 310 is 0.35 mm to 0.43 mm.

[0091] (Third embodiment) In the battery pack of the present invention, the side beam 220 may have an insertion groove 222 into which the spark prevention member 300 can be inserted.

[0092] FIG. 12 shows a process of combining an upper case 100 and a pack case 200 included in a battery pack according to a third embodiment of the present invention, and FIG. 13 shows a cross section of the pack case 200 where the discharge hole 221 is located and the upper case 100 where the spark prevention member 300 is located in the battery pack of FIG. 12.

[0093] 12 and 13, the side beam 220 includes an insertion groove 222 that is open at the top and into which the spark prevention member 300 can be inserted.

[0094] The upper case 100 is coupled to the pack case 200 by inserting the spark prevention member 300 into the insertion groove 222. At this time, it is preferable that the spark prevention member 300 is disposed so as not to come into contact with the side beam 220 in which the insertion groove 222 is formed.

[0095] The insertion groove 222 is formed at a position where the discharge hole 221 is formed so as to intersect with the discharge hole 221 .

[0096] Therefore, the movement of the spark particles p passing through the discharge hole 221 can be restricted by the spark prevention member 300 inserted into the insertion groove 222 .

[0097] However, gas g can be smoothly discharged to the outside not only through mesh holes 310 of spark prevention member 300 but also through gap Gp between insertion groove 222 and spark prevention member 300 .

[0098] In the battery pack according to the third embodiment of the present invention, as in the first embodiment, the size of the material that can pass through is limited depending on the size of the mesh holes 310, and the average diameter d of the mesh holes 310 is 0.1 mm to 0.43 mm. If the average diameter d of the mesh holes 310 is less than 0.1 mm, gas g may not be discharged as smoothly as desired, and an explosion may occur due to an increase in the internal pressure of the battery pack. Also, if the average diameter d of the mesh holes 310 exceeds 0.43 mm, there is a risk that spark particles p may pass through.

[0099] More preferably, the average diameter d of the mesh holes 310 is 0.35 mm to 0.43 mm.

[0100] (Fourth embodiment) In the battery pack of the present invention, a spark prevention member 300 having a dual design may be applied to one exhaust hole 221.

[0101] FIG. 14 shows a process of combining an upper case 100 and a pack case 200 included in a battery pack according to a fourth embodiment of the present invention, and FIG. 15 shows a cross section of the pack case 200 where the discharge hole 221 is located and the upper case 100 where the spark prevention member 300 is located in the battery pack of FIG. 14.

[0102] As shown in FIGS. 14 and 15, a pair of spark prevention members 300 corresponding to the at least one discharge hole 221 are provided.

[0103] The pair of spark prevention members 300 are provided at the lower end of the upper case 100 to face each other with a predetermined gap therebetween.

[0104] Specifically, one of the pair of spark prevention members 300 is located inside the side beam 220, and the other is located outside the side beam 220. In this case, it is preferable that the pair of spark prevention members 300 are arranged so as not to come into contact with the side beam 220.

[0105] Therefore, the spark particles p generated inside the battery pack are restricted from moving to the outside by the pair of spark prevention members 300 designed in a dual manner.

[0106] Specifically, the movement of the gas g generated inside the battery pack may be primarily restricted by the spark prevention member 300 located inside the pack case 200, and may be secondarily restricted by the spark prevention member 300 located outside the pack case 200.

[0107] However, gas g generated inside the battery pack can be discharged to the outside through the mesh holes 310 formed in each spark prevention member 300, and can also be discharged to the outside secondarily through the gap Gp between each spark prevention member 300 and the side beam 220.

[0108] In the battery pack according to the fourth embodiment of the present invention, as in the first embodiment, the size of the material that can pass through is limited depending on the size of the mesh holes 310, and the average diameter d of the mesh holes 310 is 0.1 mm to 0.43 mm. If the average diameter d of the mesh holes 310 is less than 0.1 mm, gas g may not be discharged as smoothly as desired, and an explosion may occur due to an increase in the internal pressure of the battery pack. Also, if the average diameter d of the mesh holes 310 exceeds 0.43 mm, there is a risk that spark particles p may pass through.

[0109] More preferably, the average diameter d of the mesh holes 310 is 0.35 mm to 0.43 mm.

[0110] The present invention will be described in more detail below with reference to specific examples. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0111] <Preparing Cell Ignition Equipment E> FIG. 16 shows a cell ignition device E that is prepared to intentionally cause thermal runaway in a cell C to generate a spark, and FIG. 17 shows a cross section of the cell ignition device E shown in FIG. 16.

[0112] The cell ignition equipment E has a box shape with both sides open, and contains a cell C used in the experiment and a heating pad Ph for igniting the cell C. As shown in FIG. 16, a partition W including a spark prevention member 300 is installed on both sides of the cell C. Therefore, the cell C used in the experiment and the heating pad Ph are isolated from the outside by the partition W, except for the spark prevention member 300.

[0113] In addition, in the cell ignition equipment E, a tempered glass Gs is installed on the upper part where the partition wall W is joined, for checking whether a spark occurs or moves.

[0114] The cell firing device E is a replica of the environment of the battery pack, and the partition wall W corresponds to the side beam 220 of the battery pack.

[0115] As shown in FIG. 17, the cell firing device E may be divided into an outlet space communicating with the outside and an inlet space between the pair of partition walls W.

[0116] 17, a pair of pouch-type cells C are stacked side by side in the inlet space, and a heating pad Ph capable of heating up to a temperature of 200°C or more is interposed between the cells C. In this case, the cell C includes an electrode assembly in which 40 stack unit cells C, each of which is a separator-anode-separator-cathode-separator, are stacked.

[0117] 17, the upper part of the stacked cells C is supported by an upper jig G1, and the lower part of the stacked cells C is supported by a lower jig G2. Although not shown, the upper jig G1 and the lower jig G2 are fastened to each other by bolts or the like, and the cells C are pressurized by tightening the bolts.

[0118] Example 1 In the cell ignition equipment E of FIG. 16, spark prevention member 300 with mesh holes 310 having a size of 0.43 mm was used.

[0119] <Example 2> In the cell ignition equipment E of FIG. 16, spark prevention member 300 with mesh holes 310 having a size of 0.41 mm was used.

[0120] Example 3 In the cell ignition equipment E of FIG. 16, spark prevention member 300 with mesh holes 310 having a size of 0.35 mm was used.

[0121] <Comparative Example 1> In the cell ignition equipment E of FIG. 16, spark prevention member 300 with mesh holes 310 having a size of 0.6 mm was used.

[0122] <Comparative Example 2> In the cell ignition equipment E of FIG. 16, spark prevention member 300 with mesh holes 310 having a size of 0.5 mm was used.

[0123] <Comparative Example 3> In the cell ignition equipment E of FIG. 16, spark prevention member 300 with mesh holes 310 having a size of 0.48 mm was used.

[0124] <Experimental Example> The heating pad Ph of each cell ignition equipment E prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was activated, and the temperature of the heating pad Ph was increased until a spark was generated from the cell C housed therein. Then, each cell C was ignited until a spark was observed from the outside through the mesh hole 310 of each spark prevention member 300. The time from when a spark was generated from each cell C contained in the inlet space to when spark particles p were released into the outlet space of the equipment was measured and is shown in Table 1 below.

[0125] [Table 1]

[0126] 18 is a photograph showing the area where the spark prevention member 300 is located when a spark occurs in cell C of the cell ignition device E of Example 1. As can be seen from FIG. 18, the spark generated in the inlet space is prevented from being discharged to the outlet space by the spark prevention member 300.

[0127] The above-mentioned characteristics were also observed in Examples 2 and 3.

[0128] However, in the case of Comparative Example 1, after a spark occurred in cell C, spark particles p were released to the outside through mesh holes 310 within a relatively short time. Figure 19 shows a photograph of the area where spark prevention member 300 was located when a spark occurred in cell C of cell ignition equipment E of Comparative Example 1.

[0129] According to FIG. 19, a spark generated in the inlet space passes through the partition wall W and is observed in the outlet space.

[0130] In Comparative Example 2, it took a relatively long time for the spark particles p to be released compared to Comparative Example 1, but sparks could be observed in the outlet space, and an explosion due to the spark was temporarily observed. Figure 20 shows a photograph of the area where the spark prevention member 300 was located when a spark occurred in cell C of cell ignition equipment E in Comparative Example 2. As shown in Figure 20, a flame due to an explosion was observed in the outlet space.

[0131] In the case of Comparative Example 3, it took the longest time for a spark to be found in the outlet space, so it is expected to have some effect in delaying the explosion. However, in Comparative Example 3, a large flame occurred after a certain time had passed, just like in Comparative Examples 1 and 2.

[0132] The present invention has been described in more detail above through the drawings and embodiments, etc. However, the configurations shown in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0133] 10: (Prior Art) Battery Pack 20: (Prior Art) Upper Case 30: (Conventional technology) Pack case A': (Prior Art) Cell Assembly C': (prior art) cell 100: Upper case 200: Pack case 210: Base plate 220: Side beam 221: Discharge hole 222: Insertion groove 230: Center beam 240: Cross beam 300: Spark prevention material 310: Mesh hole A: Cell assembly C: Cell E: Cell firing equipment G1: Upper jig G2: Lower jig Gs: Tempered glass Ph: Heating pad W: Bulkhead g: Gas (movement) p: Spark particle (movement) Gp: Gap (spacing) d: mesh hole (average) diameter

Claims

1. 1. A battery pack containing a plurality of cell assemblies, a pack case in which the cell assembly is mounted; an upper case coupled to the pack case so as to cover an upper portion of the cell assembly placed inside the pack case; at least one spark arrestor including circular mesh holes and provided at a lower end of the upper case; At least one discharge hole communicating with the internal space is provided in a side wall of the pack case, the spark prevention member is disposed at a position corresponding to the discharge hole of the pack case, The average diameter of the mesh holes is 0.1 mm to 0.43 mm.

2. 10. The battery pack of claim 1, wherein the spark prevention member has a mesh structure.

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

4. The battery pack of claim 1 , wherein the spark prevention member is provided standing vertically on the upper case so that the mesh holes can communicate with the exhaust holes of the pack case.

5. The pack case is a base plate supporting a lower portion of the cell assembly; a center beam that crosses a center portion of the base plate and is coupled to the base plate so as to divide an internal space of the pack case into two; 5. The battery pack of claim 1, further comprising: side beams coupled to edges of the base plate to support sides of the cell assemblies.

6. The pack case includes two discharge holes, The battery pack according to claim 5 , wherein each of the exhaust holes is formed in the side wall so as to communicate with an internal space of the respective pack case defined by the center beam.

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

8. a pair of spark prevention members corresponding to the at least one discharge hole; The battery pack of claim 5 , wherein the pair of spark prevention members are provided at a lower end of the upper case to face each other with a predetermined gap therebetween.

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

10. the sidewall includes an insertion groove that is open upward so that the spark prevention member can be inserted therein; the insertion groove is formed in a position corresponding to the position where the discharge hole is formed so as to intersect with the discharge hole; The battery pack according to claim 5 , wherein the upper case is coupled to the pack case such that the spark prevention member is inserted into the insertion groove.

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

12. The battery pack according to claim 11, wherein the spark prevention member is spaced from the side wall by 0.1 mm to 1 mm.

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

14. The battery pack of claim 1 , wherein the spark prevention member comprises a flame-resistant material.

15. The battery pack of claim 1 , wherein the spark prevention member has an area larger than an area of ​​the exhaust hole.

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