Battery pack

Abstract

According to an exemplary embodiment, there is provided a battery pack including: a pack housing, a battery cell assembly, an upper cover, and a fireproof sheet interposed between the upper cover and the battery cell assembly and including a plurality of opening guides overlapping the plurality of exhaust holes, each of the plurality of opening guides including first to third dashed line portions spaced apart from each other in a first direction, each of the first to third dashed line portions extending in a second direction perpendicular to the first direction, and the first dashed line portion being different from the second dashed line portion and the third dashed line portion.

Description

Technical Field

[0001] The present invention relates to a battery pack. This application claims the benefit of Korean Application No. 10-2024-0001053, filed on January 3, 2024, which is hereby incorporated by reference in its entirety.

Background Art

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as an energy source for various wireless devices such as handsets, notebook computers, and wireless vacuum cleaners. In recent years, due to improvements in energy density and economies of scale, the manufacturing cost per unit capacity of secondary batteries has been significantly reduced, and as the driving range of battery electric vehicles (BEVs) increases to a level equivalent to that of fuel vehicles, the main application of secondary batteries has shifted from mobile devices to mobility.

[0003] In the current trend where secondary batteries for mobility are emphasized, the main directions of secondary battery technology development are cost reduction and safety improvement. Secondary batteries account for the largest proportion of the manufacturing cost of BEVs. Therefore, the most important factor for the increase in the share of BEVs over internal combustion engine vehicles is the production cost of secondary batteries. Cost reduction can be achieved by reducing raw materials, reducing the number of steps in the production process, and reducing tact time. The safety of secondary batteries is directly related to the lives of mobility passengers and is therefore very important. The main challenge for improving the safety of secondary batteries is to delay heat propagation when a thermal runaway event occurs.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the technical idea of the present invention is to provide a battery pack with improved safety.

Means for Solving the Problems

[0005] According to an exemplary embodiment of the present invention for solving the above-mentioned problems, a battery pack is provided. The battery pack includes a pack housing including a base plate; a battery cell assembly disposed on the base plate and including a plurality of battery cells; an upper cover disposed on the battery cell assembly and including a plurality of exhaust holes; and a fireproof sheet interposed between the upper cover and the battery cell assembly and including a plurality of opening guides that overlap the plurality of exhaust holes, each of the plurality of opening guides including first to third dashed lines spaced apart from each other in a first direction to be broken, each of the first to third dashed lines extending in a second direction perpendicular to the first direction, the first dashed line being different from the second and third dashed lines.

[0006] The first dashed line section described above is interposed between the second dashed line section and the third dashed line section described above.

[0007] The first dashed line portion includes a plurality of first line segments arranged along the second direction, the second dashed line portion includes a plurality of second line segments arranged along the second direction, and the third dashed line portion includes a plurality of third line segments arranged along the second direction.

[0008] The lengths of each of the first line segments described above are different from the lengths of each of the second line segments described above.

[0009] Each of the lengths of the first line segment is longer than each of the lengths of the second line segment.

[0010] The lengths of each of the first line segments described above are different from the lengths of each of the third line segments described above.

[0011] Each of the lengths of the first line segment described above is longer than each of the lengths of the third line segment described above.

[0012] The lengths of each of the second line segments described above are the same as the lengths of each of the third line segments described above.

[0013] Each of the above multiple opening guides further includes a fourth dashed section and a fifth dashed section spaced apart from each other with the first to third dashed sections in between, the fourth dashed section including a plurality of fourth line segments arranged along the second direction, and the fifth dashed section including a plurality of fifth line segments arranged along the second direction.

[0014] The lengths of each of the fourth line segments described above are the same as the lengths of each of the second line segments described above.

[0015] Each of the lengths of the first line segment described above is longer than each of the lengths of the fourth line segment described above.

[0016] The lengths of each of the fifth line segments described above are the same as the lengths of each of the third line segments described above.

[0017] Each of the lengths of the first line segment described above is longer than each of the lengths of the fifth line segment described above. [Effects of the Invention]

[0018] An exemplary embodiment of the present invention includes a fireproof sheet with an improved release guide. This allows the release guide of the corresponding fireproof sheet to rupture rapidly when a thermal runaway event occurs in a battery cell, delaying heat propagation by the ejection of gas and dust. Furthermore, when a thermal runaway event occurs, only the necessary portion of the release guide of the fireproof sheet can be opened restrictively, preventing the thermal runaway event from propagating to battery cells that are not experiencing the event.

[0019] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those having ordinary knowledge in the technical field to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects associated with implementing the exemplary embodiments of the present disclosure can also be derived by those having ordinary knowledge in the technical field from the exemplary embodiments of the present disclosure.

Brief Description of the Drawings

[0020] [Figure 1] It is a plan view for explaining a battery pack according to an exemplary embodiment. [Figure 2] It is a plan view for explaining a battery pack according to an exemplary embodiment. [Figure 3] It is a partial plan view obtained by enlarging a part of FIG. 1. [Figure 4] It is a cross-sectional view taken along the cutting line 1I-1I' of FIG. 1. [Figure 5] It is a plan view for explaining a battery pack according to an exemplary embodiment. [Figure 6] It is a partial plan view obtained by enlarging a part of FIG. 5. [Figure 7] It is a cross-sectional view taken along the cutting line 5I-5I' of FIG. 5. [Figure 8] It is a plan view for explaining a battery pack according to an exemplary embodiment. [Figure 9] It is a partial plan view obtained by enlarging a part of FIG. 8.

Modes for Carrying Out the Invention

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. On the premise, terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings, and should be construed as meanings and concepts that conform to the technical idea of the present invention based on the principle that the inventor can appropriately define the concept of the terms in order to explain the inventor's own invention in the best way.

[0022] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent all of the technical ideas of the present invention. Thus, there can be various equivalents and modifications that can replace them at the time of this application.

[0023] Also, in the description of the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, that detailed description is omitted.

[0024] Embodiments of the present invention are provided to more fully explain the present invention to an ordinary technician. Therefore, in the drawings, the shapes and sizes of the components may be exaggerated, omitted, or shown schematically for a clearer explanation. Thus, the sizes and ratios of each component do not fully reflect the actual sizes and ratios.

[0025] (First Embodiment) FIG. 1 is a plan view for explaining a battery pack 100 according to an exemplary embodiment. For a more complete understanding of the arrangement between the elements of the battery pack 100, in FIG. 1, the lid 150 (see FIG. 4) is omitted.

[0026] FIG. 2 is a plan view for explaining the battery pack 100 of FIG. 1. Compared with FIG. 1, in FIG. 2, the fireproof sheet 130 and the upper cover 140 are omitted.

[0027] FIG. 3 is a partial plan view of the partial POR1 of FIG. 1 enlarged.

[0028] FIG. 4 is a cross-sectional view taken along the cutting line 1I - 1I' of FIG. 1.

[0029] Referring to Figures 1 to 4, the battery pack 100 may include a housing 110, multiple battery cell assemblies 120_1, 120_2, 120_3, 120_4, 120_5, 120_6 (hereinafter 120_1 to 120_6), a fireproof sheet 130, an upper cover 140, and a lid 150. The battery pack 100 is the final form of a battery system installed in a mobility device or the like.

[0030] The housing 110 can provide space for arranging multiple battery cell assemblies 120_1 to 120_6. The housing 110 may include a base plate 111, side walls 112, 113, 114, 115, and a center beam 116.

[0031] The two directions substantially parallel to the mounting surface 111M of the base plate 111 are defined as the X and Y directions, and the direction substantially perpendicular to the mounting surface 111M of the base plate 111 is defined as the Z direction. The X, Y, and Z directions may each be substantially perpendicular to one another. Unless otherwise stated, the definitions of directions are the same for the following drawings.

[0032] The base plate 111 and the side walls 112, 113 can each be provided by an extrusion process. The extrusion direction of the base plate 111 and the side walls 112, 113 can be the X direction. The base plate 111 and the side walls 112, 113 can be arranged in the Y direction. The side walls 114, 115 can also be provided by an extrusion process.

[0033] According to exemplary embodiments, the base plate 111 and the side walls 112, 113 can be joined by friction stir welding. The base plate 111 may include a plurality of unit plates joined by friction stir welding.

[0034] The pack housing 110 may include a center beam 116. The center beam 116 may extend in the X direction. The center beam 116 may be interposed between the side walls 112 and 113. The center beam 116 may be included in a center plate positioned at the center of a plurality of unit plates that are friction stir welded to each other. This allows the center beam 116 to be formed together with the center plate in an extrusion process, and the center beam 116 may be a continuous element integral with the center plate.

[0035] The base plate 111 may include multiple cooling channels. These multiple cooling channels can provide passages for the movement of a coolant, such as water. The multiple cooling channels can be formed by an extrusion process. The multiple cooling channels may extend in the X direction. The multiple cooling channels may be spaced apart in the Y direction.

[0036] Multiple battery cell assemblies 120_1 to 120_6 can be placed on the base plate 111 of the housing 110. The base plate 111 can support the multiple battery cell assemblies 120_1 to 120_6. Side walls 112, 113, 114, and 115 can horizontally surround the multiple battery cell assemblies 120_1 to 120_6.

[0037] Each of the multiple battery cell assemblies 120_1 to 120_6 may include multiple battery cells 121, multiple pads 122, a first crossbeam 125a, and a second crossbeam 125b.

[0038] Each of the multiple battery cells 121 may be a lithium-ion battery. Each of the multiple battery cells 121 includes an electrode assembly, an electrolyte, and a case. Each of the multiple battery cells 121 may be one of a cylindrical battery cell, a prismatic battery cell, or a pouch-type battery cell. The electrode assembly of a cylindrical battery cell is housed in a cylindrical metal can. The electrode assembly of a prismatic battery cell is housed in a prismatic metal can. The electrode assembly of a pouch-type battery cell is housed in a pouch case containing an aluminum laminate sheet.

[0039] An electrode assembly may include a positive electrode, a negative electrode, and a separation membrane interposed between the positive and negative electrodes. The electrode assembly may be either a jelly roll type or a stack type. A jelly roll type electrode assembly may include a winding structure of the positive electrode, negative electrode, and separation membrane interposed between them. A stack type electrode assembly may include multiple sequentially stacked positive electrodes, multiple negative electrodes, and multiple separation membranes interposed between them.

[0040] Multiple battery cells 121 can constitute multiple banks. Each of these banks can contain one or more battery cells 121. One or more battery cells 121 in each of these banks can be connected in parallel. Multiple banks can be connected in series. The number of banks connected in series and the number of battery cells 121 included in each bank can be determined according to the magnitude of the voltage and current that each of the battery cell assemblies 120 is to output.

[0041] Multiple pads 122 can be interposed between multiple battery cells 121. Multiple pads 122 can horizontally pressurize the multiple battery cells 121, preventing or mitigating swelling of the multiple battery cells 121. Multiple pads 122 can isolate the multiple battery cells 121 from one another. According to an exemplary embodiment, each of the multiple battery cells 121 may be made of PU (Polyurethane). According to an exemplary embodiment, each of the multiple battery cells 121 may be made of a fire-resistant material such as silicone.

[0042] According to an exemplary embodiment, each of the plurality of pads 122 can be arranged alternately with two banks. According to an exemplary embodiment, two of the plurality of banks can be interposed between adjacent pads 122. According to another exemplary embodiment, only one bank may be interposed between adjacent pads 122, or three or more banks may be interposed.

[0043] The first crossbeam 125a and second crossbeam 125b of each battery cell assembly 120_1 to 120_6 can be spaced apart from each other with multiple battery cells 121 in between. The first crossbeam 125a and second crossbeam 125b can cover multiple battery cells 121. The first crossbeam 125a and second crossbeam 125b can horizontally support multiple battery cells 121. The first crossbeam 125a and second crossbeam 125b can be fixed to the multiple battery cells 121 by adhesive or the like.

[0044] According to exemplary embodiments, the first crossbeam 125a and the second crossbeam 125b may have different and complementary shapes. For example, the second crossbeam 125b of each of the battery cell assemblies 120_1 to 120_6 may be coupled with the first crossbeam 125a of the subsequent battery cell assembly 120_1 to 120_6. For example, the second crossbeam 125b of battery cell assembly 120_1 may be coupled with the first crossbeam 125a of battery cell assembly 120_2.

[0045] The first crossbeam 125a and the second crossbeam 125b, joined together, can constitute a crossbeam assembly CBA. Each of the first crossbeam 125a and the second crossbeam 125b in the crossbeam assembly CBA can engage with each other. Each of the first crossbeam 125a and the second crossbeam 125b in the crossbeam assembly CBA can touch each other. Each of the crossbeam assemblies CBA can extend in the Y direction.

[0046] The first crossbeam 125a of battery cell assembly 120_1 adjacent to side wall 114 can be coupled to a supporting beam 117a located on base plate 111. The second crossbeam 125b of battery cell assembly 120_3 adjacent to side wall 115 can be coupled to a supporting beam 117b located on the second crossbeam 125b. Similarly, the first crossbeam 125a of battery cell assembly 120_6 adjacent to side wall 115 can be coupled to a supporting beam 117a located on base plate 111. The second crossbeam 125b of battery cell assembly 120_4 adjacent to side wall 115 can be coupled to a supporting beam 117b located on the second crossbeam 125b.

[0047] The center beam 116 can extend in the X direction. The center beam 116 can overlap with the center of the base plate. The center beam 116 can isolate battery cell assemblies 120_1, 120_2, and 120_3 from battery cell assemblies 120_4, 120_5, and 120_6 from each other. The center beam 116 can be interposed between battery cell assemblies 120_1, 120_2, and 120_3 and battery cell assemblies 120_4, 120_5, and 120_6.

[0048] In this example, the multiple battery cell assemblies 120_1 to 120_6 are arranged in two rows and three columns. This means that the multiple battery cell assemblies 120_1 to 120_6 are arranged in a 3x2 configuration. Based on what is described here, a typical technician in the industry can easily arrive at a battery pack containing multiple battery cell assemblies 120_1 to 120_6 arranged in an MxN configuration, where M and N are any integers greater than or equal to 2.

[0049] Multiple fireproof sheets 130 can be placed on multiple battery cell assemblies 120_1 to 120_6. Multiple upper covers 140 can be placed on multiple fireproof sheets 130. Multiple upper covers 140 can cover multiple battery cell assemblies 120_1 to 120_6. Multiple fireproof sheets 130 can be interposed between the multiple upper covers 140 and the multiple battery cell assemblies 120_1 to 120_6.

[0050] Each of the multiple top covers 140 may include an insulating material. For example, each of the multiple top covers 140 may include fire-resistant plastic. According to other exemplary embodiments, each of the multiple top covers 140 may include a metal such as aluminum and stainless steel. The multiple top covers 140 can overlap with the multiple battery cell assemblies 120_1 to 120_6 in the Z direction. The multiple top covers 140 may be substantially parallel to the mounting surface 111M of the base plate 111. The multiple top covers 140 may be substantially perpendicular to the Z direction.

[0051] Multiple upper covers 140 can be interposed between multiple battery cell assemblies 120_1 to 120_6 and the lid 150. Multiple upper covers 140 can be separated from the lid 150 in the Z direction. The space between the multiple upper covers 140 and the lid 150 can be an exhaust path.

[0052] Each of the multiple upper covers 140 may include multiple exhaust holes 140H that expose a corresponding portion of one of the multiple fireproof sheets 130. The multiple exhaust holes 140H may overlap with the multiple battery cells 121 in the Z direction.

[0053] Each of the multiple exhaust holes 140H may be rectangular. The corners of each of the multiple exhaust holes 140H may, but are not limited to, have a rounded shape. The length of each of the multiple exhaust holes 140H in the X direction may differ from the length of each of the multiple exhaust holes 140H in the Y direction. The length of each of the multiple exhaust holes 140H in the X direction may be shorter than the length of each of the multiple exhaust holes 140H in the Y direction.

[0054] The length in the Y direction of each of the multiple exhaust holes 140H may differ from the length in the Y direction of each of the multiple battery cells 121. The length in the Y direction of each of the multiple exhaust holes 140H may be shorter than the length in the Y direction of each of the multiple battery cells 121. This allows each of the multiple battery cells 121 to overlap with two or more (e.g., three) exhaust holes 140H in the Z direction.

[0055] The length of each of the multiple exhaust holes 140H in the X direction may differ from the length of each of the multiple battery cells 121 in the X direction. The length of each of the multiple exhaust holes 140H in the X direction may be longer than the length of each of the multiple battery cells 121 in the X direction. This allows the multiple exhaust holes 140H to overlap with two or more (e.g., six) portions of the battery cells 121 in the Z direction. In this example, there are six battery cells corresponding to two banks between the pads 122, or between the pads 122 and the crossbeams 125a, 125b, and each of the multiple exhaust holes 140H can overlap with a portion of the six battery cells 121 in the Z direction.

[0056] Each of the multiple fire-resistant sheets 130 may contain a refractory material such as mica. Each of the multiple fire-resistant sheets 130 may have a low thermal conductivity and a high ignition point.

[0057] Each of the multiple fireproof sheets 130 may include multiple opening guides 130G that overlap with multiple exhaust holes 140H. Each of the multiple opening guides 130G may have relatively weak physical strength. If a thermal runaway event occurs in one of the multiple battery cell assemblies 120_1 to 120_6, the multiple opening guides 130G overlapping with the multiple exhaust holes 140H can easily rupture, thereby providing an exhaust path for the hot gas through the multiple exhaust holes 140H.

[0058] Here, thermal runaway in multiple battery cell assemblies 120_1 to 120_6 is a state in which the temperature change in multiple battery cell assemblies 120_1 to 120_6 further accelerates that temperature change, resulting in an uncontrollable positive feedback loop. In a thermal runaway state, multiple battery cell assemblies 120_1 to 120_6 exhibit a rapid temperature increase and emit large amounts of high-pressure gas and combustion residue.

[0059] Each of the multiple release guides 130G may include first to fifth dashed sections 130D1, 130D2, 130D3, 130D4, and 130D5 (hereinafter referred to as 130D1 to 130D5). According to an exemplary embodiment, each of the first to fifth dashed sections 130D1 to 130D5 may include a plurality of line segments, which are localized portions with relatively weak physical strength, arranged along a second direction.

[0060] According to an exemplary embodiment, the first to fifth dashed sections 130D1 to 130D5 may be substantially the same as each other. Thus, each of the line segments of the first to fifth dashed sections 130D1 to 130D5 may be substantially the same as each other. The lengths and spacings of each of the line segments included in the first to fifth dashed sections 130D1 to 130D5 may be substantially the same as each other.

[0061] The first dashed line section 130D1 can be interposed between the second dashed line section 130D2 and the third dashed line section 130D3. The fourth dashed line section 130D4 can be separated from the first dashed line section 130D1 with the second dashed line section 130D2 in between. The fifth dashed line section 130D5 can be separated from the first dashed line section 130D1 with the third dashed line section 130D3 in between.

[0062] The fourth dashed line 130D4 can overlap in the Z direction with the boundary between the first battery cell 121 and the second battery cell, among the six battery cells 121 that overlap with the exhaust hole 140H. The second dashed line 130D2 can overlap in the Z direction with the boundary between the second battery cell 121 and the third battery cell, among the six battery cells 121 that overlap with the exhaust hole 140H. The first dashed line 130D1 can overlap in the Z direction with the boundary between the third battery cell 121 and the fourth battery cell, among the six battery cells 121 that overlap with the exhaust hole 140H. The third dashed line 130D3 can overlap in the Z direction with the boundary between the fourth battery cell 121 and the fifth battery cell, among the six battery cells 121 that overlap with the exhaust hole 140H. The fifth dashed line section 130D5 can overlap in the Z direction with the boundary between the fifth battery cell 121 and the sixth battery cell, among the six battery cells 121 that overlap with the exhaust hole 140H.

[0063] Each of the multiple exhaust holes 140H overlaps with one of the six battery cells 121, and the first to fifth dashed lines 130D1 to 130D5 divide the portion of the fireproof sheet 130 that overlaps with each of the multiple exhaust holes 140H into six regions. This allows only the corresponding portion of the fireproof sheet 130 to open if a thermal runaway event occurs in only some of the multiple battery cells 121, and the hot gas and dust discharged through the open portion of the fireproof sheet 130 can be isolated from the battery cells 121 under normal conditions.

[0064] For example, if a thermal runaway event occurs in the first battery cell 121 that overlaps with the exhaust hole 140H, only the portion of the fire-resistant sheet 130 between the fourth dashed line portion 130D4 and the edge of the exhaust hole 140H parallel to the Y direction can be ruptured.

[0065] For example, if a thermal runaway event occurs in the second battery cell 121 which overlaps with the exhaust hole 140H, only the portion of the fire-resistant sheet 130 between the second dashed line portion 130D2 and the fourth dashed line portion 130D4 can be ruptured.

[0066] For example, if a thermal runaway event occurs in the third battery cell 121 which overlaps with the exhaust hole 140H, only the portion of the fire-resistant sheet 130 between the first dashed line portion 130D1 and the second dashed line portion 130D2 can be ruptured.

[0067] For example, if a thermal runaway event occurs in the fourth battery cell 121, which overlaps with the exhaust hole 140H, only the portion of the fire-resistant sheet 130 between the first dashed line portion 130D1 and the third dashed line portion 130D3 can be ruptured.

[0068] For example, if a thermal runaway event occurs in the fifth battery cell 121 which overlaps with the exhaust hole 140H, only the portion of the fire-resistant sheet 130 between the third dashed line portion 130D3 and the fifth dashed line portion 130D5 can be ruptured.

[0069] For example, if a thermal runaway event occurs in the sixth battery cell 121 which overlaps with the exhaust hole 140H, only the portion of the fire-resistant sheet 130 between the fifth dashed line portion 130D5 and the edge of the exhaust hole 140H parallel to the Y direction can be ruptured.

[0070] The lid 150 can be coupled to the side walls 112, 113, 114, and 115. The lid 150 can be fixed to the side walls 112, 113, 114, and 115 by mechanical means such as bolts. The lid 150 can cover elements located inside the battery pack 100, such as battery cell assemblies 120_1 to 120_6 and electrical components. A gasket can be interposed between the lid and the side walls 112, 113, 114, and 115. The gasket can provide liquid-tightness to the battery pack 100.

[0071] The battery pack 100 may further include electrical components. These electrical components may include any electronic elements necessary to power the battery pack. The electrical components may be placed on the electrical component mounting area (EMR).

[0072] Electrical components may include, for example, a Battery Management System (BMS). The BMS can be configured to perform tasks such as monitoring, balancing, and controlling the battery pack. Monitoring of the battery pack 100 may include measuring the voltage and current of specific nodes within a plurality of battery cell assemblies 120_1 to 120_6 and measuring the temperature of a set location within the battery pack 100. The battery pack 100 may include measuring instruments for measuring the aforementioned voltage, current, and temperature.

[0073] Balancing the battery pack 100 is an operation that reduces deviations between multiple battery cell assemblies 120_1 to 120_6. Control of the battery pack 100 includes preventing overcharging, over-discharging, and overcurrent. Through monitoring, balancing, and control, the battery pack 100 can operate under optimal conditions, thereby preventing shortening of the lifespan of each of the multiple battery cell assemblies 120_1 to 120_6.

[0074] The electrical components may further include a cooling system, a Power Relay Assembly (PRA), and a safety plug. The cooling system may include a cooling fan. The cooling fan can prevent overheating of each of the multiple battery cell assemblies 120_1 to 120_6 by circulating air inside the battery pack 100. The PRA can be configured to supply or cut off power from the high-voltage battery to an external load (e.g., the vehicle's motor). The PRA can protect the multiple battery cell assemblies 120_1 to 120_6 and the external load (e.g., the vehicle's motor) by cutting off the power supply to the external load (e.g., the vehicle's motor) in situations where abnormal voltages occur, such as voltage surges.

[0075] The battery pack 100 may further include multiple exhaust devices. These exhaust devices can be installed on the lid 150 and any one of the side walls 112, 113, 114, or 115. The multiple exhaust devices can provide a path for releasing hot gases from inside the battery pack 100 to the outside in the event of a thermal runaway event occurring in some of the battery cell assemblies 120_1 to 120_6. This can delay thermal propagation and improve the stability of the battery pack 100.

[0076] (Second Embodiment) Figure 5 is a plan view illustrating a battery pack 101 according to an exemplary embodiment. In Figure 5, the lid 150 (see Figure 7) is omitted.

[0077] Figure 6 is a magnified partial plan view of part POR5 in Figure 5.

[0078] Figure 7 is a cross-sectional view along the cutting line 5I-5I' in Figure 5.

[0079] Referring to Figures 5 to 7, the battery pack 101 may include a housing 110, multiple battery cell assemblies 120_1 to 120_6 (see Figure 2), a fireproof sheet 131, an upper cover 141, and a lid 150. The battery pack 101 is the final form of a battery system installed in a mobility device or the like.

[0080] The housing 110, the multiple battery cell assemblies 120_1 to 120_6 (see Figure 2), and the lid 150 are substantially the same as those described with reference to Figures 1 to 6, so their redundant descriptions are omitted.

[0081] Multiple fireproof sheets 131 can be placed on multiple battery cell assemblies 120_1 to 120_6 (see Figure 2). Multiple upper covers 141 can be placed on multiple fireproof sheets 131. Multiple upper covers 141 can cover multiple battery cell assemblies 120_1 to 120_6 (see Figure 2). Multiple fireproof sheets 131 can be interposed between multiple upper covers 141 and multiple battery cell assemblies 120_1 to 120_6 (see Figure 2).

[0082] Each of the multiple upper covers 141 may contain an insulating material. For example, each of the multiple upper covers 141 may contain fire-resistant plastic. According to other exemplary embodiments, each of the multiple upper covers 141 may contain a metal such as aluminum and stainless steel. The multiple upper covers 141 can overlap with the multiple battery cell assemblies 120_1 to 120_6 (see Figure 2) in the Z direction.

[0083] Multiple upper covers 141 can be interposed between multiple battery cell assemblies 120_1 to 120_6 (see Figure 2) and the lid 150. Multiple upper covers 141 can be separated from the lid 150 in the Z direction. The space between the multiple upper covers 141 and the lid 150 can be an exhaust path.

[0084] Each of the multiple upper covers 141 may include multiple exhaust holes 141H that expose a corresponding portion of one of the multiple fireproof sheets 131. The multiple exhaust holes 141H may overlap with the multiple battery cells 121 in the Z direction.

[0085] Each of the multiple exhaust holes 141H may be rectangular. The length of each of the multiple exhaust holes 141H in the X direction may be different from the length of each of the multiple exhaust holes 141H in the Y direction. The length of each of the multiple exhaust holes 141H in the X direction may be shorter than the length of each of the multiple exhaust holes 141H in the Y direction.

[0086] The length in the Y direction of each of the multiple exhaust holes 141H may differ from the length in the Y direction of each of the multiple battery cells 121. The length in the Y direction of each of the multiple exhaust holes 141H may be shorter than the length in the Y direction of each of the multiple battery cells 121. This allows each of the multiple battery cells 121 to overlap with two or more (e.g., three) exhaust holes 141H in the Z direction.

[0087] The length of each of the multiple exhaust holes 141H in the X direction may differ from the length of each of the multiple battery cells 121 in the X direction. The length of each of the multiple exhaust holes 141H in the X direction may be longer than the length of each of the multiple battery cells 121 in the X direction. This allows the multiple exhaust holes 141H to overlap with two or more (e.g., three) parts of the battery cells 121.

[0088] In this example, there are six battery cells corresponding to two banks between the pads 122, or between the pads 122 and the crossbeams 125a, 125b, and multiple exhaust holes 141H can overlap with portions of three battery cells 121 corresponding to one bank. That is, the exhaust holes 141H and opening guides 131G in Figure 7 can have a relatively smaller size in the X direction compared to the exhaust holes 140H and opening guides 130G in Figure 4, which can reduce the size of the fireproof sheet 131 that is opened to its maximum extent in the event of a thermal runaway event.

[0089] Each of the multiple fire-resistant sheets 131 may contain a refractory material such as mica. Each of the multiple fire-resistant sheets 131 may have a low thermal conductivity and a high ignition point.

[0090] Each of the multiple fireproof sheets 131 may include multiple opening guides 131G that overlap with multiple exhaust holes 141H. Each of the multiple opening guides 131G may have relatively weak physical strength. If a thermal runaway event occurs in one of the multiple battery cell assemblies 120_1 to 120_6 (see Figure 2), the multiple opening guides 131G overlapping with the multiple exhaust holes 141H can easily rupture, thereby providing an exhaust path for the hot gas through the multiple exhaust holes 141H.

[0091] Each of the multiple release guides 131G may include a first dashed line portion 131D1 and a second dashed line portion 131D2. According to an exemplary embodiment, each of the first dashed line portion 131D1 and the second dashed line portion 131D2 may include a plurality of line segments arranged along a second direction.

[0092] According to an exemplary embodiment, the first dashed line section 131D1 and the second dashed line section 131D2 may be substantially the same as each other. Thus, each of the line segment portions included in the first dashed line section 131D1 and the second dashed line section 131D2 may be substantially the same as each other. The lengths and spacings of each of the line segment portions included in the first dashed line section 131D1 and the second dashed line section 131D2 may be substantially the same as each other.

[0093] Each of the multiple exhaust holes 141H overlaps with three battery cells 121, and the first dashed line 131D1 and the second dashed line 131D2 can divide the portion of the fireproof sheet 131 that overlaps with each of the multiple exhaust holes 141H into three regions. This allows only the corresponding portion of the fireproof sheet 131 to be opened if a thermal runaway event occurs in only some of the multiple battery cells 121, and the hot gas and dust discharged through the opened portion of the fireproof sheet 131 can be isolated from the battery cells 121 under normal conditions.

[0094] For example, if a thermal runaway event occurs in the first battery cell 121 that overlaps with the exhaust hole 141H, only the portion of the fire-resistant sheet 131 between the first dashed line portion 131D1 and the edge of the exhaust hole 141H parallel to the Y direction can be ruptured.

[0095] For example, if a thermal runaway event occurs in the second battery cell 121 which overlaps with the exhaust hole 141H, only the portion of the fire-resistant sheet 131 between the first dashed line portion 131D1 and the second dashed line portion 131D2 can be ruptured.

[0096] For example, if a thermal runaway event occurs in the third battery cell 121 that overlaps with the exhaust hole 141H, only the portion of the fire-resistant sheet 131 between the second dashed line portion 131D2 and the edge of the exhaust hole 141H parallel to the Y direction can be ruptured.

[0097] (Third embodiment) Figure 8 is a plan view illustrating a battery pack 102 according to an exemplary embodiment. In Figure 8, the lid 150 (see Figure 4) is omitted.

[0098] Figure 9 is a magnified partial plan view of part POR8 in Figure 8.

[0099] Referring to Figures 8 and 9, the battery pack 102 may include a housing 110, multiple battery cell assemblies 120_1 to 120_6 (see Figure 2), a fireproof sheet 132, an upper cover 140, and a lid 150. The battery pack 102 is the final form of a battery system installed in a mobility device or the like.

[0100] The housing 110, the multiple battery cell assemblies 120_1 to 120_6 (see Figure 2), the top cover 140, and the lid 150 are substantially the same as those described with reference to Figures 1 to 4, so their redundant descriptions are omitted.

[0101] Each of the multiple fire-resistant sheets 132 may contain a refractory material such as mica. Each of the multiple fire-resistant sheets 132 may have a low thermal conductivity and a high ignition point.

[0102] Each of the multiple fireproof sheets 132 may include multiple opening guides 132G that overlap with multiple exhaust holes 140H. Each of the multiple opening guides 132G may have relatively weak physical strength. If a thermal runaway event occurs in one of the multiple battery cell assemblies 120_1 to 120_6 (see Figure 2), the multiple opening guides 132G overlapping with the multiple exhaust holes 140H can easily rupture, thereby providing an exhaust path for the hot gas through the multiple exhaust holes 140H.

[0103] Each of the multiple release guides 132G may include the first to fifth dashed sections 132D1, 132D2, 132D3, 132D4, and 132D5 (hereinafter referred to as 132D1 to 132D5). According to an exemplary embodiment, each of the first to fifth dashed sections 132D1 to 132D5 may include a plurality of line segments arranged along a second direction.

[0104] Each of the line segments in the first dashed line section 132D1 can be called the first line segment. Each of the line segments in the second dashed line section 132D2 can be called the second line segment. Each of the line segments in the third dashed line section 132D3 can be called the third line segment. Each of the line segments in the fourth dashed line section 132D4 can be called the fourth line segment. Each of the line segments in the fifth dashed line section 132D5 can be called the fifth line segment.

[0105] According to an exemplary embodiment, the first dashed line portion 132D1 may differ from the second to fifth dashed line portions 132D2, 132D3, 132D4, and 132D5 (hereinafter referred to as 132D2 to 132D5). According to an exemplary embodiment, each of the first line segments may differ from each of the second to fifth line segments.

[0106] According to an exemplary embodiment, the length of each of the first line segment may differ from the lengths of each of the second to fifth line segment parts. According to an exemplary embodiment, the length of each of the first line segment parts may be longer than the lengths of each of the second to fifth line segment parts.

[0107] According to an exemplary embodiment, the second to fifth dashed sections 132D2, 132D3, 132D4, and 132D5 may be substantially the same as one another. Thus, the lengths and spacing of each of the second to fifth line segments may be substantially the same as one another.

[0108] The first dashed line section 132D1 can be interposed between the second dashed line section 132D2 and the third dashed line section 132D3. The fourth dashed line section 132D4 can be separated from the first dashed line section 132D1 with the second dashed line section 132D2 in between. The fifth dashed line section 132D5 can be separated from the first dashed line section 132D1 with the third dashed line section 132D3 in between.

[0109] Each of the multiple exhaust holes 140H overlaps with one of the six battery cells 121, and the first to fifth dashed lines 132D1 to 132D5 divide the portion of the fireproof sheet 132 that overlaps with each of the multiple exhaust holes 140H into six regions. This allows only the corresponding portion of the fireproof sheet 132 to be opened if a thermal runaway event occurs in only some of the multiple battery cells 121 (see Figure 4), and the hot gas and dust discharged through the opened portion of the fireproof sheet 132 can be isolated from the battery cells 121 under normal conditions.

[0110] Furthermore, the first dashed section 132D1 can limit the portion of the fireproof sheet 132 that is opened to approximately half of each of the multiple exhaust holes 140H. According to an exemplary embodiment, the physical strength of the first dashed section 132D1 may differ from that of the second to fifth dashed sections 132D2 to 132D5, thereby allowing the maximum opening width of the fireproof sheet 132 to be adjusted by the arrangement of the first dashed section 132D1. Based on what is described herein, ordinary technicians of the art can easily arrive at embodiments in which the opening guide 132G includes two or more first dashed sections 132D1.

[0111] The present invention has been described in more detail above with reference to the drawings and embodiments. However, the configurations described in the drawings or embodiments described herein are merely one embodiment of the present invention and do not represent the entire technical concept of the present invention. Therefore, there may be a variety of equivalents and modifications that can be substituted for them at the time of filing.

Claims

1. Pack housing including base plate, A battery cell assembly comprising a plurality of battery cells is disposed on the base plate, A top cover, which is placed on the aforementioned battery cell assembly and includes a plurality of exhaust holes, A fireproof sheet interposed between the upper cover and the battery cell assembly, including a plurality of opening guides that overlap the plurality of exhaust holes, Each of the aforementioned multiple release guides includes first to third dashed sections spaced apart from each other in a first direction, A battery pack comprising a plurality of line segments, each of which the first to third dashed lines extend in a second direction perpendicular to the first direction and are arranged along the second direction, and which have local, relatively weak physical strength.

2. The battery pack according to claim 1, wherein the first dashed line portion is interposed between the second dashed line portion and the third dashed line portion.

3. The first dashed line portion includes a plurality of first line segments arranged along the second direction, The second dashed line portion includes a plurality of second line segments arranged along the second direction, The battery pack according to claim 1, wherein the third dashed line portion includes a plurality of third line segments arranged along the second direction.

4. The battery pack according to claim 3, wherein the length of each of the first line segments is different from the length of each of the second line segments.

5. The battery pack according to claim 3, wherein the length of each of the first line segments is longer than the length of each of the second line segments.

6. The battery pack according to claim 3, wherein the length of each of the first line segments is different from the length of each of the third line segments.

7. The battery pack according to claim 3, wherein the length of each of the first line segments is longer than the length of each of the third line segments.

8. The battery pack according to claim 3, wherein the length of each of the second line segments is the same as the length of each of the third line segments.

9. Each of the aforementioned multiple release guides further includes a fourth dashed section and a fifth dashed section separated from each other with the first to third dashed sections in between, The fourth dashed line portion includes a plurality of fourth line segments arranged along the second direction, The battery pack according to claim 3, wherein the fifth dashed line portion includes a plurality of fifth line segments arranged along the second direction.

10. The battery pack according to claim 9, wherein the length of each of the fourth line segments is the same as the length of each of the second line segments.

11. The battery pack according to claim 9, wherein the length of each of the first line segments is longer than the length of each of the fourth line segments.

12. The battery pack according to claim 9, wherein the length of each of the fifth line segment portions is the same as the length of each of the third line segment portions.

13. The battery pack according to claim 9, wherein the length of each of the first line segments is longer than the length of each of the fifth line segments.

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