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] This application claims the benefit of Korean Application No. 10-2024-0001053, filed on January 3, 2024, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for various wireless devices such as handsets, laptops, and wireless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of secondary batteries, and as the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the main use of secondary batteries has shifted from mobile devices to mobility.

[0003] In the current trend of emphasizing secondary batteries for mobility, the main direction of secondary battery technology development is to reduce production costs and improve safety. Secondary batteries account for the largest proportion of BEV manufacturing costs. Therefore, the most important factor in increasing the share of BEVs compared to internal combustion engine vehicles is the production cost of secondary batteries. Reduction in production costs can be achieved by reducing raw materials, the number of steps in the production process, and takt time. Secondary battery safety is extremely important because it directly affects the lives of mobility passengers. The main challenge in improving secondary battery safety is to slow down heat propagation when a thermal runaway event occurs. Summary of the Invention [Problem 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 problem]

[0005] According to an exemplary embodiment of the present invention to solve the above-mentioned problems, there is provided a battery pack including: 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 overlapping the plurality of exhaust holes, wherein each of the opening guides includes first to third dashed line portions spaced apart from each other in a first direction along which the fireproof sheet should break, 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 and third dashed line portions.

[0006] The first broken line portion is interposed between the second broken line portion and the third broken line portion.

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

[0008] The length of each of the first line segments is different from the length of each of the second line segments.

[0009] The length of each of the first line segments is longer than the length of each of the second line segments.

[0010] The length of each of the first line segments is different from the length of each of the third line segments.

[0011] The length of each of the first line segments is longer than the length of each of the third line segments.

[0012] The length of each of the second line segments is the same as the length of each of the third line segments.

[0013] Each of the plurality of opening guides further includes a fourth dashed line portion and a fifth dashed line portion spaced apart from each other with the first to third dashed line portions interposed therebetween, the fourth dashed line portion including a plurality of fourth line segment portions arranged along the second direction, and the fifth dashed line portion including a plurality of fifth line segment portions arranged along the second direction.

[0014] The length of each of the fourth line segments is the same as the length of each of the second line segments.

[0015] The length of each of the first line segments is longer than the length of each of the fourth line segments.

[0016] The length of each of the fifth line segments is the same as the length of each of the third line segments.

[0017] The length of each of the first line segment portions is longer than the length of each of the fifth line segment portions. [Effects of the Invention]

[0018] A battery pack according to an exemplary embodiment of the present invention may include a fire-resistant sheet including an improved opening guide. When a thermal runaway event occurs in a battery cell, the opening guide of the corresponding fire-resistant sheet can be quickly broken, slowing heat propagation due to the release of gas and dust. Furthermore, when a thermal runaway event occurs, only a necessary portion of the opening guide of the fire-resistant sheet can be opened in a limited manner, preventing the thermal runaway event from propagating to a battery cell where the thermal runaway event does not occur.

[0019] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood from the following description by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure belong. In other words, unintended effects accompanying the implementation of the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a plan view illustrating a battery pack according to an exemplary embodiment. [Figure 2] FIG. 1 is a plan view illustrating a battery pack according to an exemplary embodiment. [Figure 3] FIG. 2 is an enlarged partial plan view of a portion of FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along the line 1I-1I′ in FIG. [Figure 5] FIG. 1 is a plan view illustrating a battery pack according to an exemplary embodiment. [Figure 6] FIG. 6 is an enlarged partial plan view of a portion of FIG. 5. [Figure 7] FIG. 5 is a cross-sectional view taken along the line 5I-5I′ in FIG. [Figure 8] FIG. 1 is a plan view illustrating a battery pack according to an exemplary embodiment. [Figure 9] FIG. 9 is an enlarged partial plan view of a portion of FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. As a premise, the terms and words used in this 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 an inventor can appropriately define the concept of terms in order to best describe his / her own invention.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] (First embodiment) 1 is a plan view illustrating a battery pack 100 according to an exemplary embodiment. In order to more fully understand the arrangement between the elements of the battery pack 100, a lid 150 (see FIG. 4) is omitted from FIG. 1.

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

[0027] FIG. 3 is an enlarged partial plan view of the portion POR1 of FIG.

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

[0029] 1 to 4, a battery pack 100 may include a housing 110, a plurality of battery cell assemblies 120_1, 120_2, 120_3, 120_4, 120_5, and 120_6 (hereinafter referred to as 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 to be installed in a mobility or the like.

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

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

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

[0033] According to an exemplary embodiment, the base plate 111 and the side walls 112, 113 may 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, 113. The center beam 116 may be included in a center plate disposed at the center of a plurality of unit plates that are friction stir welded together. Thus, the center beam 116 may 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 a plurality of cooling channels. The plurality of cooling channels may provide a passageway for the movement of a coolant, such as water. The plurality of cooling channels may be formed by an extrusion process. The plurality of cooling channels may extend in the X direction. The plurality of cooling channels may be spaced apart in the Y direction.

[0036] The plurality of battery cell assemblies 120_1 to 120_6 may be disposed on a base plate 111 of the housing 110. The base plate 111 may support the plurality of battery cell assemblies 120_1 to 120_6. The side walls 112, 113, 114, and 115 may horizontally surround the plurality of battery cell assemblies 120_1 to 120_6.

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

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

[0039] The electrode assembly may include a positive electrode, a negative electrode, and a separator 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 rolled structure of a positive electrode, a negative electrode, and a separator interposed therebetween. A stack type electrode assembly may include a plurality of sequentially stacked positive electrodes, a plurality of negative electrodes, and a plurality of separators interposed therebetween.

[0040] The plurality of battery cells 121 may constitute a plurality of banks. Each of the plurality of banks may include one or more battery cells 121. The one or more battery cells 121 in each of the plurality of banks may be connected in parallel to each other. The plurality of banks may be connected in series to each other. The number of series-connected banks and the number of battery cells 121 included in the plurality of banks may be determined depending on the magnitude of the voltage and current to be output from each of the battery cell assemblies 120.

[0041] The pads 122 may be interposed between the battery cells 121. The pads 122 may apply horizontal pressure to the battery cells 121 and prevent or mitigate swelling of the battery cells 121. The pads 122 may isolate the battery cells 121 from each other. According to an exemplary embodiment, each of the battery cells 121 may include PU (Poly Urethane). According to an exemplary embodiment, each of the battery cells 121 may include a fire-resistant material such as silicone.

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

[0043] The first cross beam 125a and the second cross beam 125b of each of the battery cell assemblies 120_1 to 120_6 may be spaced apart from each other with the plurality of battery cells 121 therebetween. The first cross beam 125a and the second cross beam 125b may cover the plurality of battery cells 121. The first cross beam 125a and the second cross beam 125b may horizontally support the plurality of battery cells 121. The first cross beam 125a and the second cross beam 125b may be fixed to the plurality of battery cells 121 by an adhesive or the like.

[0044] According to an exemplary embodiment, the first cross beam 125a and the second cross beam 125b may have different but complementary shapes. For example, the second cross beam 125b of each of the battery cell assemblies 120_1 to 120_6 may be coupled to the first cross beam 125a of the subsequent one of the battery cell assemblies 120_1 to 120_6. For example, the second cross beam 125b of the battery cell assembly 120_1 may be coupled to the first cross beam 125a of the battery cell assembly 120_2.

[0045] The first cross beam 125a and the second cross beam 125b coupled to each other may constitute a cross beam assembly CBA. The first cross beam 125a and the second cross beam 125b of each cross beam assembly CBA may engage with each other. The first cross beam 125a and the second cross beam 125b of each cross beam assembly CBA may abut each other. Each of the cross beam assemblies CBA may extend in the Y direction.

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

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

[0048] In this example, the plurality of battery cell assemblies 120_1 to 120_6 are arranged in two rows and three columns. This means that the plurality of battery cell assemblies 120_1 to 120_6 are arranged in a 3×2 array. Based on what is described herein, a person skilled in the art can easily arrive at a battery pack including a plurality of battery cell assemblies 120_1 to 120_6 arranged in an M×N array, where M and N are each any integer greater than or equal to 2.

[0049] A plurality of fire-resistant sheets 130 may be disposed on the plurality of battery cell assemblies 120_1 to 120_6. A plurality of upper covers 140 may be disposed on the plurality of fire-resistant sheets 130. The plurality of upper covers 140 may cover the plurality of battery cell assemblies 120_1 to 120_6. The plurality of fire-resistant sheets 130 may be interposed between the plurality of upper covers 140 and the plurality of battery cell assemblies 120_1 to 120_6.

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

[0051] The plurality of upper covers 140 may be interposed between the plurality of battery cell assemblies 120_1 to 120_6 and the lid 150. The plurality of upper covers 140 may be spaced apart from the lid 150 in the Z direction. A space between the plurality of upper covers 140 and the lid 150 may be an exhaust path.

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

[0053] Each of the exhaust holes 140H may be rectangular. The corners of each of the exhaust holes 140H may be rounded, but this is not limiting. The length of each of the exhaust holes 140H in the X direction may be different from the length of each of the exhaust holes 140H in the Y direction. The length of each of the exhaust holes 140H in the X direction may be shorter than the length of each of the exhaust holes 140H in the Y direction.

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

[0055] The X-direction length of each of the plurality of exhaust holes 140H may be different from the X-direction length of each of the plurality of battery cells 121. The X-direction length of each of the plurality of exhaust holes 140H may be longer than the X-direction length of each of the plurality of battery cells 121. This allows the plurality of exhaust holes 140H to overlap portions of two or more (e.g., six) 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 cross beams 125a, 125b, and each of the plurality of exhaust holes 140H can overlap portions of the six battery cells 121 in the Z direction.

[0056] Each of the plurality of fire-resistant sheets 130 may include a fire-resistant material such as mica, etc. Each of the plurality of fire-resistant sheets 130 may have a low thermal conductivity and a high ignition point.

[0057] Each of the plurality of fire-resistant sheets 130 may include a plurality of opening guides 130G overlapping with the plurality of exhaust holes 140H. Each of the plurality of opening guides 130G may have relatively weak physical strength. When a thermal runaway event occurs in one of the plurality of battery cell assemblies 120_1 to 120_6, the plurality of opening guides 130G overlapping with the plurality of exhaust holes 140H may be easily broken, thereby providing an exhaust path for high-temperature gas through the plurality of exhaust holes 140H.

[0058] Here, thermal runaway of the battery cell assemblies 120_1 to 120_6 is a state in which the temperature change of the battery cell assemblies 120_1 to 120_6 further accelerates the temperature change, which is an uncontrollable positive feedback. The battery cell assemblies 120_1 to 120_6 in the thermal runaway state exhibit a rapid temperature rise and emit a large amount of high-pressure gas and combustion debris.

[0059] Each of the plurality of opening guides 130G may include first to fifth broken line portions 130D1, 130D2, 130D3, 130D4, and 130D5 (hereinafter, 130D1 to 130D5). According to an exemplary embodiment, each of the first to fifth broken line portions 130D1 to 130D5 may include a plurality of line segments that are arranged along the second direction and have a localized relatively weak physical strength.

[0060] According to an exemplary embodiment, the first to fifth dashed line portions 130D1 to 130D5 may be substantially the same as one another. Accordingly, the line segments of the first to fifth dashed line portions 130D1 to 130D5 may be substantially the same as one another. The lengths and intervals of the line segments included in the first to fifth dashed line portions 130D1 to 130D5 may be substantially the same as one another.

[0061] The first broken line portion 130D1 may be interposed between the second broken line portion 130D2 and the third broken line portion 130D3. The fourth broken line portion 130D4 may be spaced apart from the first broken line portion 130D1 with the second broken line portion 130D2 in between. The fifth broken line portion 130D5 may be spaced apart from the first broken line portion 130D1 with the third broken line portion 130D3 in between.

[0062] The fourth broken line portion 130D4 may overlap in the Z direction with a boundary between a first battery cell 121 and a second battery cell among the six battery cells 121 overlapping with the exhaust hole 140H. The second broken line portion 130D2 may overlap in the Z direction with a boundary between a second battery cell 121 and a third battery cell among the six battery cells 121 overlapping with the exhaust hole 140H. The first broken line portion 130D1 may overlap in the Z direction with a boundary between a third battery cell 121 and a fourth battery cell among the six battery cells 121 overlapping with the exhaust hole 140H. The third broken line portion 130D3 may overlap in the Z direction with a boundary between a fourth battery cell 121 and a fifth battery cell among the six battery cells 121 overlapping with the exhaust hole 140H. The fifth broken line portion 130D5 may 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 overlapping with the exhaust hole 140H.

[0063] Each of the plurality of exhaust holes 140H overlaps six battery cells 121, and the first to fifth dashed line portions 130D1 to 130D5 can divide the portion of the fire-resistant sheet 130 that overlaps with each of the plurality of exhaust holes 140H into six regions. As a result, when a thermal runaway event occurs in only some of the plurality of battery cells 121, only the corresponding portion of the fire-resistant sheet 130 can be opened, and high-temperature gas and dust discharged through the opened portion of the fire-resistant sheet 130 can be blocked from the battery cells 121 in a normal state.

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

[0065] For example, if a thermal runaway event occurs in the second battery cell 121 that overlaps the vent hole 140H, only the portion of the fireproof sheet 130 between the second dashed line portion 130D2 and the fourth dashed line portion 130D4 can break.

[0066] For example, if a thermal runaway event occurs in the third battery cell 121 that overlaps the vent hole 140H, only the portion of the fireproof sheet 130 between the first broken line portion 130D1 and the second broken line portion 130D2 can break.

[0067] For example, if a thermal runaway event occurs in the fourth battery cell 121 that overlaps the vent hole 140H, only the portion of the fireproof sheet 130 between the first broken line portion 130D1 and the third broken line portion 130D3 can break.

[0068] For example, if a thermal runaway event occurs in the fifth battery cell 121 that overlaps the vent hole 140H, only the portion of the fireproof sheet 130 between the third dashed line portion 130D3 and the fifth dashed line portion 130D5 can break.

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

[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 disposed inside the battery pack 100, such as the battery cell assemblies 120_1 to 120_6 and electrical components. Gaskets can be interposed between the lid and the side walls 112, 113, 114, and 115. The gaskets can provide the battery pack 100 with a liquid-tight seal.

[0071] The battery pack 100 may further include electrical components. The electrical components may include any electronic elements necessary to drive the battery pack. The electrical components may be disposed on the electrical component mounting region EMR.

[0072] The electrical components may include, for example, a BMS (Battery Management System). The BMS may be configured to monitor, balance, and control the battery pack. Monitoring the battery pack 100 may include measuring the voltage and current of specific nodes within the plurality of battery cell assemblies 120_1 to 120_6 and measuring the temperature at a set position within the battery pack 100. The battery pack 100 may include measuring instruments for measuring the voltage, current, and temperature described above.

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

[0074] The electrical components may further include a cooling device, a power relay assembly (PRA), a safety plug, etc. The cooling device may include a cooling fan. The cooling fan circulates air inside the battery pack 100 to prevent overheating of each of the plurality of battery cell assemblies 120_1 to 120_6. The PRA may be configured to supply or cut off power from the high-voltage battery to an external load (e.g., a vehicle motor). The PRA can protect the plurality of battery cell assemblies 120_1 to 120_6 and the external load (e.g., a vehicle motor) by cutting off the power supply to the external load (e.g., a vehicle motor) in a situation where an abnormal voltage such as a voltage surge occurs.

[0075] The battery pack 100 may further include a plurality of exhaust devices. The plurality of exhaust devices may be installed on any one of the lid 150 and the side walls 112, 113, 114, and 115. The plurality of exhaust devices may provide a path for releasing high-temperature gas inside the battery pack 100 to the outside when a thermal runaway event occurs in some of the battery cell assemblies 120_1 to 120_6. This may slow down thermal propagation, thereby improving the stability of the battery pack 100.

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

[0077] FIG. 6 is an enlarged partial plan view of the portion POR5 of FIG.

[0078] FIG. 7 is a cross-sectional view taken along section line 5I-5I' in FIG.

[0079] 5 to 7, the battery pack 101 may include a housing 110, a plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 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 to be installed in a mobility or the like.

[0080] The housing 110, the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2), and the lid 150 are substantially the same as those described with reference to FIGS. 1 to 6, and therefore, a duplicated description thereof will be omitted.

[0081] A plurality of fireproof sheets 131 may be disposed on the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2). A plurality of upper covers 141 may be disposed on the plurality of fireproof sheets 131. The plurality of upper covers 141 may cover the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2). The plurality of fireproof sheets 131 may be interposed between the plurality of upper covers 141 and the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2).

[0082] Each of the plurality of upper covers 141 may include an insulating material. For example, each of the plurality of upper covers 141 may include a fire-resistant plastic. According to another exemplary embodiment, each of the plurality of upper covers 141 may include a metal such as aluminum or stainless steel. The plurality of upper covers 141 may overlap the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2) in the Z direction.

[0083] The plurality of upper covers 141 may be interposed between the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2) and the lid 150. The plurality of upper covers 141 may be spaced apart from the lid 150 in the Z direction. The space between the plurality of upper covers 141 and the lid 150 may be an exhaust path.

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

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

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

[0087] The X-direction length of each of the plurality of exhaust holes 141H may be different from the X-direction length of each of the plurality of battery cells 121. The X-direction length of each of the plurality of exhaust holes 141H may be longer than the X-direction length of each of the plurality of battery cells 121. This allows the plurality of exhaust holes 141H to overlap portions of two or more (e.g., three) 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 cross beams 125a, 125b, and the 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 FIG. 7 can have a relatively smaller size in the X direction than the exhaust holes 140H and opening guides 130G in FIG. 4, which can reduce the size of the fire-resistant sheet 131 that is most likely to open in the event of a thermal runaway event.

[0089] Each of the plurality of fire-resistant sheets 131 may include a fire-resistant material such as mica, etc. Each of the plurality of fire-resistant sheets 131 may have a low thermal conductivity and a high ignition point.

[0090] Each of the plurality of fire-resistant sheets 131 may include a plurality of opening guides 131G overlapping with the plurality of exhaust holes 141H. Each of the plurality of opening guides 131G may have relatively weak physical strength. When a thermal runaway event occurs in one of the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2), the plurality of opening guides 131G overlapping with the plurality of exhaust holes 141H can be easily broken, thereby providing an exhaust path for high-temperature gas through the plurality of exhaust holes 141H.

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

[0092] According to an exemplary embodiment, the first dashed line portion 131D1 and the second dashed line portion 131D2 may be substantially the same as each other. Accordingly, the line segments included in the first dashed line portion 131D1 and the second dashed line portion 131D2 may be substantially the same as each other. The lengths and intervals of the line segments included in the first dashed line portion 131D1 and the second dashed line portion 131D2 may be substantially the same as each other.

[0093] Each of the plurality of exhaust holes 141H overlaps three battery cells 121, and the first broken line portion 131D1 and the second broken line portion 131D2 can divide the portion of the fire-resistant sheet 131 that overlaps with each of the plurality of exhaust holes 141H into three regions. As a result, when a thermal runaway event occurs in only some of the plurality of battery cells 121, only the corresponding portion of the fire-resistant sheet 131 can be opened, and high-temperature gas and dust discharged through the opened portion of the fire-resistant sheet 131 can be blocked from the battery cells 121 in a normal state.

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

[0095] For example, if a thermal runaway event occurs in the second battery cell 121 that overlaps the vent hole 141H, only the portion of the fireproof sheet 131 between the first broken line portion 131D1 and the second broken line portion 131D2 can break.

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

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

[0098] FIG. 9 is an enlarged partial plan view of the portion POR8 of FIG.

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

[0100] The housing 110, the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2), the top cover 140, and the lid 150 are substantially the same as those described with reference to FIGS. 1 to 4, and therefore, redundant description thereof will be omitted.

[0101] Each of the plurality of fire-resistant sheets 132 may include a fire-resistant material such as mica, etc. Each of the plurality of fire-resistant sheets 132 may have a low thermal conductivity and a high ignition point.

[0102] Each of the plurality of fire-resistant sheets 132 may include a plurality of opening guides 132G overlapping with the plurality of exhaust holes 140H. Each of the plurality of opening guides 132G may have relatively weak physical strength. In the event of a thermal runaway event occurring in one of the plurality of battery cell assemblies 120_1 to 120_6 (see FIG. 2), the plurality of opening guides 132G overlapping with the plurality of exhaust holes 140H may be easily broken, thereby providing an exhaust path for high-temperature gas via the plurality of exhaust holes 140H.

[0103] Each of the plurality of opening guides 132G may include first to fifth broken line portions 132D1, 132D2, 132D3, 132D4, and 132D5 (hereinafter, 132D1 to 132D5). According to an exemplary embodiment, each of the first to fifth broken line portions 132D1 to 132D5 includes a plurality of line segment portions arranged along the second direction.

[0104] Each of the line segments of the first dashed line portion 132D1 can be referred to as a first line segment. Each of the line segments of the second dashed line portion 132D2 can be referred to as a second line segment. Each of the line segments of the third dashed line portion 132D3 can be referred to as a third line segment. Each of the line segments of the fourth dashed line portion 132D4 can be referred to as a fourth line segment. Each of the line segments of the fifth dashed line portion 132D5 can be referred to as a fifth line segment.

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

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

[0107] According to an exemplary embodiment, the second to fifth dashed line portions 132D2, 132D3, 132D4, and 132D5 may be substantially the same as one another, so that the lengths and intervals of the second to fifth line segment portions may be substantially the same as one another.

[0108] The first broken line portion 132D1 may be interposed between the second broken line portion 132D2 and the third broken line portion 132D3. The fourth broken line portion 132D4 may be spaced apart from the first broken line portion 132D1 with the second broken line portion 132D2 therebetween. The fifth broken line portion 132D5 may be spaced apart from the first broken line portion 132D1 with the third broken line portion 132D3 therebetween.

[0109] Each of the plurality of exhaust holes 140H overlaps six battery cells 121, and the first to fifth dashed line portions 132D1 to 132D5 can divide the portion of the fireproof sheet 132 that overlaps with each of the plurality of exhaust holes 140H into six regions. As a result, when a thermal runaway event occurs in only some of the plurality of battery cells 121 (see FIG. 4), only the corresponding portion of the fireproof sheet 132 can be opened, and high-temperature gas and dust discharged through the opened portion of the fireproof sheet 132 can be blocked from the battery cells 121 in a normal state.

[0110] Furthermore, the first dashed line portion 132D1 can limit the open portion of the fire-resistant sheet 132 to approximately half of each of the plurality of exhaust holes 140H. According to an exemplary embodiment, the physical strength of the first dashed line portion 132D1 can be different from the physical strength of the second to fifth dashed line portions 132D2 to 132D5, thereby adjusting the maximum open width of the fire-resistant sheet 132 by adjusting the arrangement of the first dashed line portion 132D1. Based on what is described herein, a person of ordinary skill in the art can easily arrive at an embodiment in which the opening guide 132G includes two or more first dashed line portions 132D1.

[0111] The present invention has been described in more detail above with reference to 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.

Claims

1. 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; a fireproof sheet interposed between the upper cover and the battery cell assembly, the fireproof sheet including a plurality of opening guides overlapping the plurality of exhaust holes; Each of the plurality of opening guides includes first to third broken line portions spaced apart from each other in a first direction, each of the first to third broken line portions extends in a second direction perpendicular to the first direction; The first dashed line portion is different from the second dashed line portion and the third dashed line portion.

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

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

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

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

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

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

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

9. each of the plurality of opening guides further includes a fourth dashed line portion and a fifth dashed line portion spaced apart from each other with the first to third dashed line portions interposed therebetween; the fourth broken line portion includes a plurality of fourth line segment portions arranged along the second direction, The battery pack according to claim 3 , wherein the fifth broken line portion includes a plurality of fifth line segments arranged along the second direction.

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

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

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

Images