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 pack case in which the cell assemblies are seated; an upper case coupled to the pack case to cover the upper part of the cell assemblies seated inside the pack case; and at least one spark prevention member including circular mesh holes and provided at the lower end of the upper case, wherein the pack case includes at least one discharge hole, communicating with an inner space, in a side portion thereof, the spark prevention member is provided at a position corresponding to the discharge hole of the pack case, and the average diameter of the mesh holes is 0.1 mm to 0.5 mm.

Description

battery pack

[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 discharge hole and an upper case provided with a spark prevention member having a mesh structure corresponding to the discharge hole.

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2023-0117979, dated September 5, 2023, and all contents of the document in said Korean patent application are incorporated herein by reference.

[0003]

[0004] Lithium secondary batteries are typically categorized into cells comprising an electrode assembly in which electrodes and separators are alternately laminated, electrode leads connected to the electrodes, and a case that encloses and seals the electrode assembly so that the electrode leads extend outward. Depending on the shape of the electrode assembly and the shape of the case, cells can be categorized into cylindrical cells, square cells, and pouch-shaped cells.

[0005] Since the output produced by the above single cell is not large, when applied to vehicles, etc., multiple cells are connected to obtain the desired output.

[0006] Figure 1 illustrates a cell assembly (A') in which a plurality of cells (C') are stacked and combined, and a conventional battery pack (10) in which the cell assembly (A') is accommodated.

[0007] In general, a battery pack (10) is composed of a pack case (30) in which a cell assembly (A') is mounted, as shown in the above drawing 1, and an upper case (20) that is coupled to the pack case (30) to cover the upper portion of the mounted cell assembly (A').

[0008] An electric vehicle may be equipped with a battery pack (10) as shown in the above-described Figure 1, and an electric vehicle equipped with a battery pack (10) may obtain a large output through a plurality of cell assemblies (A') included in one battery pack (10).

[0009] The battery pack (10) capable of achieving such high output as described above carries the risk of explosion, fire, etc. due to overheating. Therefore, ensuring safety as well as energy efficiency is one of the most important tasks for battery packs (10) applied to electric vehicles, etc. If such an abnormal phenomenon is not properly responded to in the early stages, the internal temperature of the battery pack (10) may rapidly rise due to overheating, and this rise in temperature may cause thermal runaway of the cell (C').

[0010] To enhance the safety of various electrical products, including electric vehicles, various countries are requiring secondary battery manufacturers to meet certain safety requirements. For example, China has proposed a regulatory framework, GB 38031-2020, which requires the introduction of a system capable of controlling thermal runaway within five minutes of a cell (C').

[0011] Not only in China but also in many countries, there is a demand for a battery pack (10) having a structure that can effectively control the abnormal phenomenon of the accepted cell (C') before it develops into an explosion or fire of the battery pack (10).

[0012] Meanwhile, when examining the thermal runaway process of the cell assembly (A'), high-temperature gas generated by the vaporization of the electrolyte inside the cell assembly (A') is released, and spark particles may be generated due to short circuits of electrodes, etc. A typical battery pack (10) is provided with a gas discharge path on the side through which the gas can be released to prevent the internal pressure from rapidly increasing due to the high-temperature gas as described above. However, there is a risk of explosion if the generated spark particles jump out into the oxygen-rich outside through the gas discharge path.

[0013] Therefore, when a thermal runaway situation occurs inside the cell (C'), there is a need to develop a battery pack (10) having a structure that can suppress the emission of spark particles and selectively discharge only gas.

[0014]

[0015] Accordingly, the present invention was created to solve the above problems, and aims to provide a battery pack having a structure capable of selectively releasing only high-temperature gas in a thermal runaway situation.

[0016] Other objects and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0017] According to the present invention, a battery pack accommodating a plurality of cell assemblies is provided.

[0018] The battery pack comprises: a pack case in which a cell assembly is mounted; an upper case coupled to the pack case to cover an upper portion of the cell assembly mounted inside the pack case; and at least one spark prevention member provided at a lower end of the upper case, the upper case including a circular mesh hole; wherein the pack case includes at least one exhaust hole communicating with an internal space on a side thereof, the spark prevention member is provided at a position corresponding to the exhaust hole of the pack case, and the average diameter of the mesh hole is 0.1 mm to 0.43 mm.

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

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

[0021] The above spark prevention member may be installed so that the mesh hole is vertical to the upper case so that it can communicate with the discharge hole of the pack case.

[0022] The pack case may include a base plate supporting the lower portion of the cell assembly; a center beam extending across the center of the base plate and coupled to the base plate to divide the internal space of the pack case into two; and a side beam coupled to the edge of the base plate to support the side portion of the cell assembly.

[0023] The pack case may include two discharge holes, and each discharge hole may be formed in the side wall so as to communicate with the internal space of each pack case partitioned by the center beam.

[0024] The above spark prevention member may be located on at least one of the inner and outer sides of the side wall.

[0025] A pair of spark prevention members are paired and correspond to the above one discharge hole,

[0026] The pair of spark arresters may be provided at the bottom of the upper case so as to face each other at a predetermined interval.

[0027] One of the pair of spark arresters may be positioned on the inside of the side wall, and the other may be positioned on the outside of the side wall.

[0028] The side wall includes an insertion groove that is open upward so that the spark prevention member can be inserted, and the insertion groove is formed corresponding to a position where the discharge hole is formed so as to intersect with the discharge hole, and the upper case can be combined with the pack case so that the spark prevention member can be inserted into the insertion groove.

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

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

[0031] The above spark prevention member may include an electrically insulating material.

[0032] The above spark prevention member may include a flame retardant material.

[0033] The above spark prevention member may have an area larger than the area of ​​the discharge hole.

[0034] According to the present invention, explosion and fire of a battery pack can be prevented in advance.

[0035] Figure 1 illustrates a conventional battery pack and a cell assembly accommodated in the battery pack.

[0036] FIG. 2 is a front perspective view of a battery pack according to the first embodiment of the present invention.

[0037] Figure 3 shows a rear perspective view of the battery pack of Figure 2.

[0038] Figure 4 is a front view of the spark arrester.

[0039] Figure 5 is a perspective view of the bottom of the spark arrester.

[0040] Figure 6 shows the process of combining the upper case and the pack case.

[0041] Fig. 7 shows a cross-section of the pack case in which the discharge hole is located and the upper case in which the spark prevention member is located in the battery pack of Fig. 6.

[0042] Figure 8 shows that gas generated inside the battery pack is discharged to the outside through the exhaust hole.

[0043] Figure 9 shows the movement of spark particles generated inside the battery pack.

[0044] FIG. 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.

[0045] Fig. 11 shows a cross-section of the pack case in which the discharge hole is located and the upper case in which the spark prevention member is located in the battery pack of Fig. 10.

[0046] Fig. 12 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.

[0047] Fig. 13 shows a cross-section of the pack case in which the discharge hole is located and the upper case in which the spark prevention member is located in the battery pack of Fig. 12.

[0048] Fig. 14 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.

[0049] Fig. 15 shows a cross-section of the pack case in which the discharge hole is located and the upper case in which the spark prevention member is located in the battery pack of Fig. 14.

[0050] Figure 16 shows the cell ignition equipment prepared for the experiment.

[0051] Figure 17 shows a cross-section of the cell ignition device of Figure 16.

[0052] Figure 18 shows the experimental results of Example 1.

[0053] Figure 19 shows the experimental results of Comparative Example 1.

[0054] Figure 20 shows the experimental results of Comparative Example 2.

[0055] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concept of a term to best explain his or her invention, they should be construed as meanings and concepts consistent with the technical spirit of the present invention.

[0056] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0057] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0058] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0059]

[0060]

[0061] The present invention relates to a battery pack having a structure in which a plurality of cell assemblies are accommodated and only high-temperature gases generated in a thermal runaway situation of the cells can be selectively released.

[0062] The battery pack of the present invention includes a pack case including at least one discharge hole and an upper case provided with a spark prevention member having a mesh structure corresponding to the discharge hole.

[0063] In particular, the battery pack of the present invention is characterized by optimally limiting the mesh hole size of the spark prevention member.

[0064] The above cell assembly comprises a plurality of cells stacked in one direction.

[0065] The above cell is composed of an electrode assembly in which electrodes and separators are alternately laminated, an electrode lead connected to the electrodes, a cell case that encloses the electrode assembly so as to be sealed, and an electrolyte filled within the cell case together with the electrode assembly.

[0066] The above cell may be configured as a pouch-shaped cell, a cylindrical cell, or a square cell depending on the shape of the cell case, and the present invention does not specifically limit this.

[0067] The above cell assembly may further include a frame that surrounds at least one side of the cell stack to protect the cell stack from external impact, etc.

[0068] FIGS. 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 to be used in experiments of the present invention, and FIGS. 18 to 20 relate to experimental results of examples and comparative examples.

[0069] Hereinafter, specific embodiments of the battery pack of the present invention will be described in detail with reference to the attached drawings. Note that the directions used in the following description to designate relative positions, such as front-back, up-down, left-right, etc., are intended to aid understanding of the invention, and unless otherwise specified, the directions depicted in the drawings will be used as a reference.

[0070]

[0071] (First embodiment)

[0072] FIG. 2 is a front perspective view of a battery pack according to a first embodiment of the present invention, and FIG. 3 is a rear perspective view of the battery pack of FIG. 2.

[0073] The battery pack of the present invention includes a pack case (200) in which a cell assembly (A) is mounted, and an upper case (100) coupled with the pack case (200) to cover the upper portion of the cell assembly (A) mounted inside the pack case (200).

[0074] The pack case (200) more specifically includes a base plate (210) that supports the lower portion of the cell assembly (A), a side beam (220) that is coupled to the edge of the base plate (210) to support the side portion of the cell assembly (A), and a center beam (230) that crosses the center of the base plate (210) and is coupled to the base plate (210) to divide the internal space of the pack case (200) into two.

[0075] Additionally, the pack case (200) may further include a cross beam (240) at each end of which is connected to the center beam (230) and side beam (220).

[0076] The above cross beam (240) serves to re-divide the internal space of the pack case (200) partitioned by the center beam (230) into cell assembly (A) units. However, the cross beam (240) may be excluded as needed.

[0077] The internal space of the pack case (200) may be partitioned by the center beam (230) and the cross beam (240), but in reality, each of the partitioned spaces may be connected to each other. For example, when gas (g) is generated in a cell assembly (A) stored in any of the partitioned spaces, the internal pressure of the internal space of the pack case (200) may be uniformly increased in any region.

[0078] The pack case (200) includes at least one discharge hole (221) on the side that communicates with the internal space. That is, the pack case (200) may have a discharge hole (221) formed on one side so that gas (g) generated inside can be discharged to the outside.

[0079] Specifically, the discharge hole (221) may be formed in the side beam (220) as illustrated in FIG. 2. Accordingly, when one cell assembly (A) experiences thermal runaway and generates high-temperature gas (g), the gas (g) can move to the discharge hole (221) and be discharged to the outside.

[0080] The pack case (200) of the present invention includes at least two discharge holes (221), and each discharge hole (221) is formed in the side beam (220) so as to be connected to the internal space of each pack case (200) partitioned by the center beam (230).

[0081] The above discharge hole (221) can be formed on either the front or rear surface of the pack case (200).

[0082] According to the above drawing 2, two discharge holes (221) are formed on each side based on the joining portion of the center beam (230) and the side beam (220).

[0083] The upper case (100) is coupled to the upper end of the side beam (220) so that the internal space of the pack case (200) can be blocked from the outside.

[0084]

[0085] 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) to selectively pass only gas (g).

[0086] Figure 4 is a front view of the spark prevention member (300), and Figure 5 is a bottom perspective view of the spark prevention member (300).

[0087] The above spark prevention member (300) has a mesh structure and includes a plurality of mesh holes (310) as shown in FIG. 4.

[0088] The mesh hole (310) of the above spark prevention member (300) allows gas (g) to pass through and prevents movement of spark particles (p), etc.

[0089] It is preferable that the above spark prevention member (300) includes a flame-resistant material so as not to be damaged by high-temperature gas (g), etc. In addition, it is preferable that it includes an electrically insulating material so as to block the flow of electricity.

[0090] The shape of the above mesh hole (310) may be circular as shown, but is not limited thereto and may be polygonal.

[0091] The spark prevention member (300) is connected at its upper end to the lower end of the upper case (100). More specifically, the spark prevention member (300) is installed so as to be vertical to the upper case (100), as illustrated in FIG. 5. Accordingly, the gas (g) can move horizontally and pass through the mesh hole (310) of the spark prevention member (300).

[0092] The battery pack of the present invention is characterized in that the spark prevention member (300) is provided at a position corresponding to the discharge hole (221) of the pack case (200).

[0093] Figure 6 shows the process of combining the upper case (100) and the pack case (200).

[0094] According to the above drawing 6, a discharge hole (221) is formed in the side beam (220), and the spark prevention member (300) is provided at the bottom of the upper case (100) at a position corresponding to each discharge hole (221).

[0095] The spark prevention member (300) included in the battery pack according to the first embodiment is provided at the bottom of the upper case (100) so as to be positioned inside the side beam (220) as shown in the above-described FIG. 6.

[0096] The spark prevention member (300) that is vertically connected to the lower portion of the upper case (100) is shaped to cover the discharge hole (221) when the upper case (100) is connected to the pack case (200). That is, when the upper case (100) and the pack case (200) are connected to each other, the mesh hole (310) of the spark prevention member (300) is connected to the discharge hole (221) of the pack case (200).

[0097] 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. 6.

[0098] It is preferable that the above spark prevention member (300) has an area larger than the area of ​​the discharge hole (221) so as to be able to block spark particles (p) flying out toward the discharge hole (221).

[0099] The above spark prevention member (300) is provided in a position where it can cover and block the entire discharge hole (221) as shown in FIG. 7.

[0100] However, the spark prevention member (300) is provided at a position spaced apart by a predetermined distance 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 the bottom of the upper case (100) at a position spaced apart by a predetermined distance in the horizontal direction from the side beam (220).

[0101] Accordingly, a gap (Gp) can be formed between the spark prevention member (300) and the side beam (220).

[0102] The above gap (Gp) serves as an auxiliary passage through which the gas (g) discharged through the mesh hole (310) travels directly to the discharge hole (221) without passing through the spark prevention member (300).

[0103] When a large amount of gas (g) is generated inside the battery pack, it may be impossible to quickly discharge the gas (g) through the mesh hole (310) of the spark prevention member (300). Therefore, in addition to the mesh hole (310), an additional passage must be secured to allow the gas (g) inside to move to the discharge hole (221), and the gap (Gp) between the spark prevention member (300) and the side beam (220) serves as the additional movement passage.

[0104] The spacing of the above gap (Gp) may vary depending on the expected amount of gas (g) and the pressure inside the battery pack.

[0105] Figure 8 shows gas (g) generated inside the battery pack being discharged to the outside through the discharge hole (221), and Figure 9 shows the movement of spark particles (p) generated inside the battery pack.

[0106] According to the above drawing 8, the gas (g) reaches the discharge hole (221) through the mesh hole (310) of the spark prevention member (300), and also reaches the discharge hole (221) through the gap (Gp) between the spark prevention member (300) and the side beam (220).

[0107] According to the above drawing 9, the spark particles (p) cannot pass through the mesh hole (310) of the spark prevention member (300) and are blocked or bounced off.

[0108] The size of the material that can pass through the mesh hole (310) is limited depending on the size of the mesh hole (310), and the average diameter (d) of the mesh hole (310) is 0.1 mm to 0.43 mm. In this case, if the average diameter (d) of the mesh hole (310) is less than 0.1 mm, the discharge of gas (g) is not as smooth as intended, and there is a risk of explosion due to an increase in the internal pressure of the battery pack. In addition, if the average diameter (d) of the mesh hole (310) exceeds 0.43 mm, there is a risk of spark particles (p) passing through.

[0109] More preferably, the average diameter (d) of the mesh hole (310) is 0.35 mm to 0.43 mm. The range of the mesh hole (310) is an optimal range that can most smoothly discharge the gas (g) while blocking the movement of spark particles (p).

[0110] Accordingly, even if a thermal runaway phenomenon occurs in one of the cell assemblies (A) accommodated 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 suppress the spark particles (p) from coming into contact with external oxygen as much as possible.

[0111]

[0112] (Second embodiment)

[0113] The battery pack of the present invention can more diversely adjust the positions of the side beam (220) and the spark prevention member (300).

[0114] FIG. 10 illustrates 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 illustrates a cross-section of a pack case (200) in which a discharge hole (221) is located and an upper case (100) in which a spark prevention member (300) is located in the battery pack of FIG. 10.

[0115] The above spark prevention member (300) is provided at the bottom of the upper case (100) so as to be positioned outside the side beam (220).

[0116] In this case, spark particles (p) that pass through the discharge hole (221) without any resistance are caught by the spark prevention member (300) located outside the discharge hole (221) and are prevented from flying out.

[0117] 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).

[0118] In the battery pack of the present invention according to the second embodiment, the size of the material that can pass through is limited according to the size of the mesh hole (310), as in the first embodiment. The average diameter (d) of the mesh hole (310) is 0.1 mm to 0.43 mm. In this case, when the average diameter (d) of the mesh hole (310) is less than 0.1 mm, the discharge of the gas (g) is not as smooth as intended, and there is a risk of explosion due to an increase in the internal pressure of the battery pack. In addition, when the average diameter (d) of the mesh hole (310) exceeds 0.43 mm, there is a risk of spark particles (p) passing through.

[0119] More preferably, the average diameter (d) of the mesh hole (310) is 0.35 mm to 0.43 mm.

[0120]

[0121] (Embodiment 3)

[0122] The battery pack of the present invention may have an insertion groove (222) formed in the side beam (220) into which the spark prevention member (300) can be inserted.

[0123] FIG. 12 illustrates 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 illustrates a cross-section of a pack case (200) in which a discharge hole (221) is located and an upper case (100) in which a spark prevention member (300) is located in the battery pack of FIG. 12.

[0124] According to the above drawings 12 and 13, the side beam (220) includes an insertion groove (222) that is opened upward so that the spark prevention member (300) can be inserted.

[0125] The upper case (100) is coupled to the pack case (200) so that the spark prevention member (300) is inserted into the insertion groove (222). At this time, it is preferable that the spark prevention member (300) is positioned so as not to touch the side beam (220) in which the insertion groove (222) is formed.

[0126] The above insertion groove (222) is formed corresponding to the position where the discharge hole (221) is formed so as to intersect with the discharge hole (221).

[0127] Accordingly, the spark particles (p) passing through the discharge hole (221) can be restricted from moving by the spark prevention member (300) inserted into the insertion groove (222).

[0128] However, in the case of gas (g), it can be smoothly discharged to the outside not only through the mesh hole (310) of the spark prevention member (300), but also through the gap (Gp) between the insertion groove (222) and the spark prevention member (300).

[0129] In the battery pack of the present invention according to the third embodiment, the size of the material that can pass through is limited according to the size of the mesh hole (310), as in the first embodiment. The average diameter (d) of the mesh hole (310) is 0.1 mm to 0.43 mm. In this case, when the average diameter (d) of the mesh hole (310) is less than 0.1 mm, the discharge of the gas (g) is not as smooth as intended, and there is a risk of explosion due to an increase in the internal pressure of the battery pack. In addition, when the average diameter (d) of the mesh hole (310) exceeds 0.43 mm, there is a risk of spark particles (p) passing through.

[0130] More preferably, the average diameter (d) of the mesh hole (310) is 0.35 mm to 0.43 mm.

[0131]

[0132] (Embodiment 4)

[0133] The battery pack of the present invention may also have a double-designed spark prevention member (300) applied to one discharge hole (221).

[0134] FIG. 14 illustrates 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 illustrates a cross-section of a pack case (200) in which a discharge hole (221) is located and an upper case (100) in which a spark prevention member (300) is located in the battery pack of FIG. 14.

[0135] A pair of spark prevention members (300) are paired and correspond to the above-mentioned single discharge hole (221) as shown in FIGS. 14 and 15.

[0136] The above pair of spark prevention members (300) are provided at the bottom of the upper case (100) so as to face each other at a predetermined interval.

[0137] Specifically, one of the pair of spark prevention members (300) is positioned on the inside of the side beam (220), and the other is positioned on the outside of the side beam (220). At this time, it is preferable that the pair of spark prevention members (300) are positioned so as not to come into contact with the side beam (220).

[0138] Therefore, spark particles (p) generated inside the battery pack are restricted from moving to the outside by the pair of double-designed spark prevention members (300).

[0139] Specifically, the movement of gas (g) generated inside the battery pack can be primarily restricted by the spark prevention member (300) located inside the pack case (200), and secondarily restricted by the spark prevention member (300) located outside the pack case (200).

[0140] However, the gas (g) generated inside the battery pack can be discharged to the outside through the mesh hole (310) formed in each spark prevention member (300) and can be auxiliary discharged to the outside through the gap (Gp) between each spark prevention member (300) and the side beam (220).

[0141] In the battery pack of the present invention according to the fourth embodiment, the size of the material that can pass through is limited according to the size of the mesh hole (310), as in the first embodiment. The average diameter (d) of the mesh hole (310) is 0.1 mm to 0.43 mm. In this case, when the average diameter (d) of the mesh hole (310) is less than 0.1 mm, the discharge of the gas (g) is not as smooth as intended, and there is a risk of explosion due to an increase in the internal pressure of the battery pack. In addition, when the average diameter (d) of the mesh hole (310) exceeds 0.43 mm, there is a risk of spark particles (p) passing through.

[0142] More preferably, the average diameter (d) of the mesh hole (310) is 0.35 mm to 0.43 mm.

[0143]

[0144] Hereinafter, the present invention will be described in more detail through specific examples. However, these examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention.

[0145]

[0146] Preparing the cell ignition equipment (E)

[0147] Fig. 16 shows a cell ignition device (E) prepared to intentionally cause a cell (C) to thermally run away and generate a spark, and Fig. 17 shows a cross-section of the cell ignition device (E) of Fig. 16.

[0148] According to the above cell ignition device (E), it is in the form of a box with both sides perforated, and inside it, a cell (C) to be used in the experiment and a heating pad (Ph) for igniting the cell (C) are located. As shown in Fig. 16, a partition wall (W) including a spark prevention member (300) is installed on both sides of the cell (C). Accordingly, the cell (C) to be used in the experiment and the heating pad (Ph) are blocked from contact with the outside by the partition wall (W), except for the spark prevention member (300).

[0149] Additionally, in the above cell ignition device (E), a tempered glass (Gs) is installed on the upper part where the partition wall (W) is combined to check whether sparks are generated and moved.

[0150] The above cell ignition device (E) simulates a battery pack environment, and the bulkhead (W) corresponds to a side beam (220) of the battery pack.

[0151] The above cell ignition device (E) can be divided into an outlet space (outlet) connected to the outside and an inlet space, which is a space between the pair of bulkheads (W), as shown in Fig. 17.

[0152] According to the above drawing 17, a pair of pouch-shaped cells (C) are stacked side by side in the inlet space, and a heating pad (Ph) capable of heating to a temperature of 200°C or higher is interposed between the cells (C). At this time, the cell (C) includes an electrode assembly in which 40 unit cells (C) for stacking a separator-cathode-separator-anode-separator are stacked.

[0153] The upper part of the above-mentioned stacked cell (C) is supported by an upper jig (G1) as illustrated in Fig. 17, and the lower part of the above-mentioned stacked cell (C) is supported by a lower jig (G2). Although not illustrated, the upper jig (G1) and the lower jig (G2) are fastened to each other with bolts or the like, and the structure is such that the cell (C) is pressurized by tightening the bolts.

[0154]

[0155] Example 1

[0156] In the cell ignition device (E) of the above-described Fig. 16, a spark prevention member (300) having a mesh hole (310) size of 0.43 mm was applied.

[0157]

[0158] Example 2

[0159] In the cell ignition device (E) of the above-described Fig. 16, a spark prevention member (300) having a mesh hole (310) size of 0.41 mm was applied.

[0160]

[0161] Example 3

[0162] In the cell ignition device (E) of the above-described Fig. 16, a spark prevention member (300) having a mesh hole (310) size of 0.35 mm was applied.

[0163]

[0164] Comparative Example 1

[0165] In the cell ignition device (E) of the above-described Fig. 16, a spark prevention member (300) having a mesh hole (310) size of 0.6 mm was applied.

[0166]

[0167] Comparative Example 2

[0168] In the cell ignition device (E) of the above-described Fig. 16, a spark prevention member (300) having a mesh hole (310) size of 0.5 mm was applied.

[0169]

[0170] Comparative Example 3

[0171] In the cell ignition device (E) of the above-described Fig. 16, a spark prevention member (300) having a mesh hole (310) size of 0.48 mm was applied.

[0172]

[0173] Experimental example

[0174] The heating pad (Ph) of each cell ignition device (E) prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was operated, and the temperature of the heating pad (Ph) was increased until a spark was generated in the cell (C) accommodated therein. Thereafter, each cell (C) was ignited until a spark was observed externally through the mesh hole (310) of each spark prevention member (300). In addition, the time from the time when a spark was generated in each cell (C) included in the inlet space (inlet) until the spark particle (p) was ejected into the outlet space (outlet) of the device was measured, and the time was recorded in Table 1 below.

[0175]

[0176] Spark ejection time (sec) Example 1 Not observable Example 2 Not observable Example 3 Not observable Comparative Example 12 Comparative Example 24 Comparative Example 317

[0177] FIG. 18 is a photograph showing the area where the spark prevention member (300) is located when a spark occurs in the cell (C) of the cell ignition device (E) of the above embodiment 1. According to FIG. 18, it can be seen that the spark generated in the inlet space (inlet) is not emitted to the outlet space (outlet) by the spark prevention member (300).

[0178] The same characteristics as above were observed in Examples 2 and 3.

[0179] However, in the case of Comparative Example 1, after a spark occurred in the cell (C), spark particles (p) were emitted to the outside through the mesh hole (310) within a relatively short period of time. Fig. 19 shows a photograph of the area where the spark prevention member (300) is located when a spark occurred in the cell (C) of the cell ignition device (E) of Comparative Example 1.

[0180] According to the above drawing 19, a spark generated in the inlet space (inlet) passes through the bulkhead (W) and is observed in the outlet space (outlet).

[0181] In the case of Comparative Example 2, it took a relatively long time for the spark particles (p) to be emitted compared to Comparative Example 1, but the spark could be observed in the outlet space (outlet), and an explosion due to the spark was temporarily observed. Fig. 20 shows a photograph of the area where the spark prevention member (300) is located when a spark occurred in the cell (C) of the cell ignition device (E) of Comparative Example 2. According to Fig. 20, a flame due to the explosion is observed in the outlet space (outlet).

[0182] In the case of Comparative Example 3, the explosion delay effect can be expected to some extent, as it took the longest time for a spark to be discovered in the outlet space. However, in Comparative Example 3, as in Comparative Examples 1 and 2, a large flame occurred after a certain period of time.

[0183]

[0184] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

[0185]

[0186] [Explanation of symbols]

[0187] 10: (Prior Art) Battery Pack

[0188] 20: (Prior art) Upper case

[0189] 30: (Prior Art) Pack Case

[0190] A': (Prior art) Cell assembly

[0191] C': (Prior art) Cell

[0192] 100: Upper case

[0193] 200: Pack Case

[0194] 210: Base Plate

[0195] 220: Side beam

[0196] 221: Exhaust hole

[0197] 222: Insertion groove

[0198] 230: Center beam

[0199] 240: Cross beam

[0200] 300: Spark arrestor

[0201] 310: Mesh hole

[0202] A: Cell assembly

[0203] C: Cell

[0204] E: Cell ignition equipment

[0205] G1: Upper jig

[0206] G2: Lower Jig

[0207] Gs: Tempered glass

[0208] Ph: Heating pad

[0209] W: Bulkhead

[0210] g: gas (movement)

[0211] p: spark particle (moving)

[0212] Gp: gap

[0213] d: mesh hole (average) diameter

Claims

1. A battery pack accommodating a plurality of cell assemblies, A pack case in which the cell assembly is mounted; An upper case coupled to the pack case to cover the upper portion of the cell assembly mounted inside the pack case; and At least one spark prevention member including a circular mesh hole and provided at the bottom of the upper case; The above pack case includes at least one exhaust hole on the side communicating with the internal space, The above spark prevention member is provided at a position corresponding to the discharge hole of the pack case, A battery pack characterized in that the average diameter of the above mesh holes is 0.1 mm to 0.43 mm.

2. In paragraph 1, The above spark prevention member is a battery pack having a mesh structure.

3. In paragraph 1, A battery pack wherein the average diameter of the above mesh holes is 0.35 mm to 0.43 mm.

4. In paragraph 1, A battery pack in which the above spark prevention member is installed vertically to the upper case so that the mesh hole can communicate with the discharge hole of the pack case.

5. In paragraph 1, The above pack case is, A base plate supporting the lower portion of the cell assembly; A center beam that crosses the center of the base plate and is joined to the base plate to divide the internal space of the pack case into two; and A battery pack comprising a side beam coupled to the edge of the base plate to support the side of the cell assembly.

6. In paragraph 5, The above pack case includes two discharge holes, A battery pack in which each of the above discharge holes is formed on the side wall so as to communicate with the internal space of each pack case partitioned by the center beam.

7. In paragraph 5, A battery pack wherein the spark prevention member is located on at least one of the inner and outer sides of the side wall.

8. In paragraph 5, A pair of spark prevention members are paired and correspond to the above one discharge hole, A battery pack in which a pair of spark prevention members are provided at the bottom of the upper case so as to face each other at a predetermined interval.

9. In paragraph 8, A battery pack wherein one of the pair of spark arresters is located on the inside of the side wall and the other is located on the outside of the side wall.

10. In paragraph 5, The above side wall includes an insertion groove open upward so that the spark prevention member can be inserted, The above insertion groove is formed corresponding to the position where the discharge hole is formed so as to intersect with the discharge hole, A battery pack in which the upper case is coupled to the pack case so that the spark prevention member is inserted into the insertion groove.

11. In paragraph 5, The above spark prevention member is a battery pack provided at the bottom of the upper case at a position spaced a predetermined distance horizontally from the side wall.

12. In paragraph 11, A battery pack in which the above spark prevention member is provided to be spaced apart from the side wall by 0.1 mm to 1 mm.

13. In paragraph 1, The above spark prevention member is a battery pack including an electrically insulating material.

14. In paragraph 1, The above spark prevention member is a battery pack including a flame retardant material.

15. In paragraph 1, A battery pack wherein the spark prevention member has an area larger than the area of ​​the discharge hole.

Images