Battery pack

Abstract

The battery pack includes a battery cell assembly having a cell block including a plurality of battery cells, and a lower cover plate disposed below the lower surface of the cell block. The battery pack includes a housing having an opening and accommodating the battery cell assembly, and a pack cover coupled to the housing and covering the opening. The battery cell assembly and a bottom wall of the housing are spaced apart from each other to form a first space, and the lower cover plate includes a vent passage communicating with the first space.

Description

[Technical Field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for a variety of 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. As the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the primary use of secondary batteries has shifted from mobile devices to mobility.

[0003] As secondary batteries are used in mobility, there is a growing demand for the safety of secondary batteries. If a secondary battery used in mobility were to cause an accident such as a fire, it could put the driver's life at risk, so research into technologies to improve the safety of secondary batteries is essential.

[0004] The background discussion provided herein is intended to generally present the context of the present disclosure. Unless otherwise expressly stated herein, the material described in this section is not prior art to the claims of this application and is not admitted as prior art or an admission of prior art by inclusion in this section. Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the technical idea of ​​the present invention is to provide a battery pack with improved safety.

[0006] These and other objects and advantages of the present disclosure can be understood from the following detailed description and will become more fully apparent from exemplary embodiments of the present disclosure. It will be readily apparent that the objects and advantages of the present disclosure can be realized by the means and combinations set forth in the appended claims. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, according to an exemplary embodiment of the present invention, a battery pack is provided.

[0008] In order to solve the above-mentioned problems, the technical idea of ​​the present invention provides a battery pack including: a battery cell assembly including a cell block including a plurality of battery cells; and a lower cover plate connected to a lower surface of the cell block; a housing having an opening and accommodating the battery cell assembly; and a pack cover connected to the housing and covering the opening, wherein the battery cell assembly and a bottom wall of the housing are spaced apart from each other to form a first space, and the lower cover plate includes a venting passage communicating with the first space.

[0009] In an exemplary embodiment, the lower cover plate includes a protruding extension that protrudes toward the first space and extends in a first direction along the lower surface of the cell block, and the venting passage includes a portion that extends in the first direction within the protruding extension.

[0010] In an exemplary embodiment, the lower cover plate includes a main plate facing the lower surface of the cell block and a protruding extension extending in a first direction along the lower surface of the cell block below the main plate, and the venting passage includes a first venting passage vertically penetrating the main plate and a second venting passage extending in the first direction within the protruding extension and having an inlet connected to the first venting passage and an outlet connected to the first space.

[0011] In an exemplary embodiment, the first venting passage extends vertically, and the second venting passage extends horizontally.

[0012] In an exemplary embodiment, the battery cell assembly further includes an upper cover plate on an upper surface of the cell block, the upper cover plate including a first cooling channel configured to allow a first cooling fluid to flow therethrough.

[0013] In an exemplary embodiment, the battery cell assembly further includes a first thermally conductive adhesive layer interposed between the upper cover plate and the cell block.

[0014] In an exemplary embodiment, the battery cell assembly is secured to the pack cover.

[0015] In an exemplary embodiment, the pack cover is characterized by including a second cooling channel configured to carry a second cooling fluid.

[0016] In an exemplary embodiment, the battery pack further includes a second thermally conductive adhesive layer interposed between the battery cell assembly and the pack cover.

[0017] In an exemplary embodiment, the battery cell assembly further includes a side cover plate on one side of the cell block, the side cover plate being fastened to the housing.

[0018] In an exemplary embodiment, the battery cell assembly further includes spaced-apart side cover plates, the cell block is disposed between the side cover plates, and the side cover plates are fixed to other support blocks provided in the housing.

[0019] In an exemplary embodiment, the sealed portion of the pouch in the pouch-type battery cell is characterized by facing the first space.

[0020] In an exemplary embodiment, each of the plurality of battery cells may be a cylindrical battery cell or a prismatic battery cell, and is characterized by including a vent portion.

[0021] In an exemplary embodiment, the venting portion of the cylindrical battery cell or the prismatic battery cell faces the first space.

[0022] In an exemplary embodiment, the present invention features providing an electric mobile device including a battery pack, the battery pack including a battery cell assembly including a cell block having a plurality of battery cells and a lower cover plate below a lower surface of the cell block, a housing having an opening and accommodating the battery cell assembly, and a pack cover coupled to the housing and covering the opening, the battery cell assembly and a bottom wall of the housing being spaced apart from each other to form a first space, and the lower cover plate including a venting passage communicating with the first space.

[0023] In an exemplary embodiment, the electric mobility device may be an electric vehicle.

[0024] In an exemplary embodiment, the battery pack further includes an exhaust portion in communication with the first space.

[0025] In an exemplary embodiment, the exhaust is located on a side of the housing opposite a rear surface of the electromobile device.

[0026] In an exemplary embodiment, the present invention provides a battery pack including: a battery cell assembly including a cell block having a plurality of battery cells, an upper cover plate on an upper surface of the cell block, a lower cover plate below a lower surface of the cell block, a side cover plate on at least one side of the cell block, and a first thermally conductive adhesive layer between the upper cover plate and the cell block, a housing having an opening and accommodating the battery cell assembly, a pack cover coupled to the housing and covering the opening, and a second thermally conductive adhesive layer between the battery cell assembly and the pack cover, wherein the battery cell assembly and a bottom wall of the housing are spaced apart from each other to form a first space, the lower cover plate includes a venting passage communicating with the first space, the upper cover plate includes a first cooling channel configured to pass a first cooling fluid therethrough, and the pack cover includes a second cooling channel configured to pass a second cooling fluid therethrough.

[0027] In an exemplary embodiment, the battery pack further includes an exhaust portion in communication with the first space.

[0028] According to an exemplary embodiment of the present invention, a free volume (first space) that serves to buffer external impact between the bottom of the battery pack and the battery cell assembly is provided, thereby preventing damage to the battery cell assembly and / or battery cells due to external impact, and ultimately improving the safety of the battery pack.

[0029] Furthermore, according to an exemplary embodiment of the present invention, the venting passages provided in the free volume and the lower cover plate of the battery cell assembly form directional venting passages in the battery pack, allowing high-temperature gas or flames in the battery pack to be discharged to the outside of the battery pack through the directional venting passages, thereby protecting passengers in the event of thermal runaway and improving the safety of the battery pack.

[0030] In addition, even if the deformation of the bottom wall of the pack housing due to an external impact exceeds the height of the free volume provided in the pack housing, the protruding extension of the lower cover plate can function as a protective member that protects the cell block, thereby improving the safety of the battery pack.

[0031] 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 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. [Effects of the Invention]

[0032] According to an exemplary embodiment of the present invention, a free volume that functions as a buffer against external impact is provided between the bottom of the battery pack and the battery cell assembly, thereby preventing damage to the battery cell assembly and / or the battery cells due to external impact and ultimately improving the stability of the battery pack.

[0033] Furthermore, according to an exemplary embodiment of the present invention, the free volume and the vent passages provided in the lower cover plate of the battery cell assembly form a directional vent passage within the battery pack, and high-temperature gas or flames within the battery pack can be discharged to the outside of the battery pack through the directional vent passage, thereby protecting passengers from a thermal runaway event and improving the safety of the battery pack.

[0034] Furthermore, even if the deformation of the bottom wall of the pack housing due to an external impact exceeds the height of the free volume provided in the pack housing, the protruding extension of the lower cover plate can function as a protective member that protects the cell block, thereby improving the safety of the battery pack. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a perspective view illustrating a battery cell assembly according to an exemplary embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view illustrating a battery cell assembly according to an exemplary embodiment of the present invention. [Figure 3] FIG. 2 is an exploded perspective view of a battery cell assembly according to an exemplary embodiment of the present invention. [Figure 4A] FIG. 2 is a cross-sectional view of a battery cell assembly according to an exemplary embodiment of the present invention. [Figure 4B] FIG. 2 is a cross-sectional view illustrating a portion of a lower cover plate of a battery cell assembly according to an exemplary embodiment of the present invention. [Figure 5] 1 is a cross-sectional view illustrating a battery pack according to an exemplary embodiment of the present invention. [Figure 6] 10A and 10B are cross-sectional views showing an example of operation of the battery pack. [Figure 7] 1 is a cross-sectional view illustrating a battery pack according to an exemplary embodiment of the present invention. [Figure 8]FIG. 10 is a cross-sectional view showing a battery pack according to another exemplary embodiment of the present invention. [Figure 9A] FIG. 10 is a cross-sectional view showing a battery pack according to another exemplary embodiment of the present invention. [Figure 9B] FIG. 9B is a perspective view showing the lower cover plate of the battery cell assembly shown in FIG. 9A. [Figure 10] 1 is a schematic diagram illustrating an electric vehicle equipped with a battery pack according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, it should be noted that the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concepts of the terms to best describe his own invention.

[0037] 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.

[0038] Furthermore, in the description of the present invention, if it is determined that a detailed description of related publicly known structures or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0039] 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 in a schematic manner for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0040] 1 to 4B are diagrams showing a battery cell assembly 100 according to an exemplary embodiment of the present invention, in which FIGS. 1 and 2 are perspective views showing the battery cell assembly 100 viewed from different directions, FIG. 3 is an exploded perspective view showing the battery cell assembly 100, FIG. 4A is a cross-sectional view showing the battery cell assembly 100, and FIG. 4B is a cross-sectional view showing a portion of the lower cover plate 125 of the battery cell assembly 100.

[0041] 1 to 4B, the battery cell assembly 100 may include a cell block 110, a case 120, and a bus bar frame assembly 141.

[0042] The cell block 110 may include multiple battery cells 111. Each battery cell 111 is the basic unit of a lithium-ion battery, i.e., a secondary battery. Each battery cell 111 may include an electrode assembly, an electrolyte, and a case. The electrode assembly housed in the case may include a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes. Depending on the assembly form, the electrode assembly may be either a jelly roll type or a stack type. A jelly roll type electrode assembly may include a wound structure of a positive electrode, a negative electrode, and a separator interposed therebetween. A stack type electrode assembly may include multiple positive electrodes, multiple negative electrodes, and multiple separators interposed therebetween, stacked in sequence. The positive electrode may include a positive electrode current collector and a positive electrode active material. The negative electrode may include a negative electrode current collector and a negative electrode active material.

[0043] The plurality of battery cells 111 may be connected in series and / or parallel. As an example, the plurality of battery cells 111 may be connected in series with each other. As another example, the plurality of battery cells 111 may be connected in parallel with each other. As another example, when a set of two or more battery cells 111 connected in parallel with each other is defined as a bank, one bank consisting of two or more battery cells 111 connected in parallel with each other and another bank consisting of two or more battery cells 111 connected in parallel with each other may be connected in series.

[0044] Each battery cell 111 may correspond to a pouch-type battery cell, a cylindrical battery cell, or a prismatic battery cell. The electrode assembly may be included in various cell cases, such as a pouch, a cylindrical can, or a prismatic can. The electrode assembly of a pouch-type battery cell is housed in a pouch case including an aluminum laminate sheet. 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. Each battery cell 111 may include a vent facing the first space. For example, the vent of each battery cell 111 may be provided in the cell casing of the battery cell 111. When the pressure inside the cell casing of each battery cell 111 exceeds a certain level, gas inside the cell casing of each battery cell 111 may be discharged to the first space through the vent of each battery cell 111. The first space may be provided between a bottom wall 511 (see FIG. 5) of a lower housing 510 (see FIG. 5) and the battery cell assembly 100 (see FIG. 5).

[0045] In an exemplary embodiment, each battery cell 111 corresponds to a pouch-type battery cell, and multiple battery cells 111 may be stacked on top of each other in a first direction (X direction) within one battery cell assembly 100 (e.g., FIG. 3 ). In an exemplary embodiment, each battery cell assembly 100 includes multiple battery cells 111 each having a length (thickness) along the first direction (X direction) that is shorter than its length along the second direction (Y direction), and multiple battery cells 111 may be stacked in the first direction (X direction). In an exemplary embodiment, each battery cell 111 may be a pouch-type battery cell, and a sealed portion of the pouch-type battery cell may face the first space to easily vent gas and / or flame from the battery cell. When the pressure within the pouch exceeds a certain level, the sealed portion of the pouch may be partially broken, and gas within the pouch may be vented through the sealed portion into the first space.

[0046] When viewed from above, the cell block 110 may have a rectangular shape, with first and second side surfaces opposite each other in a first direction (X direction), front and rear surfaces opposite each other in a second direction (Y direction), and top and bottom surfaces opposite each other in a third direction (Z direction).

[0047] The busbar frame assemblies 141 may be disposed on the front and rear surfaces of the cell block 110, respectively. The busbar frame assemblies 141 may include a busbar frame and a plurality of busbars mounted on the busbar frame. A plurality of busbars may be mounted on the busbar frame on the front surface of the cell block 110, and a plurality of busbars may be mounted on the busbar frame on the rear surface of the cell block 110. The battery cell assembly 100 may include an end plate 145 for covering the busbar frame assemblies 141 connected to the front or rear surface of the cell block 110.

[0048] The bus bars may be coupled to the electrode leads of the battery cells 111. For example, the bus bars may be coupled to the electrode leads of the battery cells 111 by welding. For example, each bus bar is an inter-bus bar that is coupled to electrode leads coupled to different battery cells 111 belonging to the cell block 110 and electrically connects the different battery cells 111 to each other. For example, each bus bar may be a terminal bus bar that electrically connects the battery cell assembly 100 to another external electrical device.

[0049] In an exemplary embodiment, the battery cell assembly 100 may include a single cell block 110. In another exemplary embodiment, the battery cell assembly 100 may include a cell block array composed of a plurality of cell blocks 110 arranged in a second direction (Y direction). For example, the battery cell assembly 100 may include two cell blocks 110 arranged in the second direction (Y direction). As an example, the battery cell assembly 100 may include a first cell block and a second cell block arranged in the second direction (Y direction), and a bus bar frame assembly 141 connected to a rear surface of the first cell block and a bus bar frame assembly 141 connected to a front surface of the second cell block may be provided between the first cell block and the second cell block. The first cell block may be electrically connected to the second cell block via an electrical connection structure extending between the bus bar frame assembly 141 connected to the rear surface of the first cell block and the bus bar frame assembly 141 connected to the front surface of the second cell block. One end plate 145 may be coupled to the bus bar frame assembly 141 on the front surface of the first cell block, and one end plate 145 may be coupled to the bus bar frame assembly 141 on the rear surface of the second cell block.

[0050] The case 120 can house the cell block 110. For example, the case 120 can surround the top, bottom, first side, and second side of each cell block 110 included in the battery cell assembly 100. The case 120 can include an upper cover plate 121 facing the top surface of the cell block 110, a lower cover plate 125 facing the bottom surface of the cell block 110, and two side cover plates 123 facing the first side and second side of the cell block 110.

[0051] The upper cover plate 121 may cover the upper surface of the cell block 110. For example, the upper cover plate 121 may cover the upper surfaces of all the cell blocks 110 provided in the battery cell assembly 100. The upper cover plate 121 may be attached to the upper surface of the cell block 110 and may be thermally coupled to the cell block 110. The upper cover plate 121 may be attached to the upper surface of the cell block 110 via a first thermally conductive adhesive layer 131 interposed between the upper cover plate 121 and the upper surface of the cell block 110. For example, the first thermally conductive adhesive layer 131 may include a thermal interface material (TIM). The upper cover plate 121 may have first cooling channels 1211 configured to allow a cooling fluid to flow therethrough and may be configured to cool the cell block 110. The upper cover plate 121 may be referred to as a cooling plate. The upper cover plate 121 may be thermally coupled to the cell block 110 via a first thermally conductive adhesive layer 131 and configured to cool the cell block 110. A cooling fluid provided from outside the battery cell assembly 100 may flow into the first cooling channel 1211 through an inlet of the first cooling channel 1211, flow along the first cooling channel 1211, and then flow out to the outside through an outlet of the first cooling channel 1211. While the cooling fluid flows along the first cooling channel 1211, cooling of the battery cell assembly 100 may be performed. For example, the upper cover plate 121 may be manufactured by bonding two plates 1213 and 1215 (e.g., FIG. 1 ), and the first cooling channel 1211 may include a space defined between the two plates 1213 and 1215.

[0052] The lower cover plate 125 may be coupled to the lower surface of the cell block 110. For example, the lower cover plate 125 may extend along the lower surfaces of all of the cell blocks 110 provided in the battery cell assembly 100. The lower cover plate 125 may include a venting passage 125v for discharging high-temperature gas originating from the cell block 110 to a space (first space) below the cell block 110. For example, the venting passage 125v of the lower cover plate 125 may communicate with a free volume provided in the pack housing 501 (see FIG. 5) and, together with the free volume FV, form a passage for discharging gas or flame within the pack housing 501.

[0053] The lower cover plate 125 may include a plurality of protruding extensions 125p that protrude toward the free volume FV (first space) of the pack housing 501. The plurality of protruding extensions 125p may extend in a horizontal direction (e.g., the X direction) along the lower surface of the cell block 110. For example, the lower cover plate 125 may include a main plate 125m and a plurality of protruding extensions 125p connected to the lower surface of the main plate 125m.

[0054] The main plate 125m may include a plurality of first venting passages 1251 vertically penetrating the main plate 125m. The first venting passages 1251 may be through-holes vertically penetrating the main plate 125m. The first venting passages 1251 extend in a vertical direction (e.g., Z direction) perpendicular to the lower surface of the cell block 110 and may guide a fluid (e.g., gas) vertically. The plurality of protruding extensions 125p may include second venting passages 1253 each communicating with the first venting passages 1251. The second venting passages 1253 may extend in a direction different from the extension direction of the first venting passages 1251. For example, the extension direction of the second venting passages 1253 may intersect or be perpendicular to the extension direction of the first venting passages 1251. For example, the second venting passage 1253 may extend horizontally (e.g., in the X direction) along the lower surface of the cell block 110 and be configured to guide a fluid (e.g., a gas) in the horizontal direction (e.g., in the X direction). The second venting passage 1253 may include an inlet communicating with the first venting passage 1251 and an outlet communicating with the free volume FV (first space) of the pack housing 501. The second venting passage 1253 may have one outlet communicating with the free volume FV (first space) of the pack housing 501 or multiple outlets communicating with the free volume FV (first space) of the pack housing 501.

[0055] The first venting passage 1251 and the second venting passage 1253 may communicate with each other to form a venting passage 125v of the lower cover plate 125. Thus, the venting passage 125v of the lower cover plate 125 may include a vertically extending portion and a horizontally extending portion. The venting passage 125v of the lower cover plate 125 may allow high-temperature gas or flame generated by the cell block 110 to be released in a predetermined direction to the free volume FV (first space) of the pack housing 501. For example, the high-temperature gas or flame generated by the cell block 110 flows downward along the first venting passage 1251, flows horizontally (e.g., in the X direction) along the second venting passage 1253, and is released through the outlet of the second venting passage 1253 into the free volume FV (first space) of the pack housing 501. The gas released through the outlet of the second venting passage 1253 can flow in the free volume FV (first space) of the pack housing 501 in the horizontal direction (e.g., the X direction in Figure 4B), which is the extension direction of the second venting passage 1253.

[0056] In an exemplary embodiment, within the main plate 125m of the lower cover plate 125, the multiple first venting passages 1251 may be arranged in the second direction (the Y direction in FIG. 2 ) and spaced apart from one another in the second direction (the Y direction). When viewed from a plane, the multiple battery cells 111 in each cell block 110 may be stacked in the first direction (the X direction), and each first venting passage 1251 may extend in the first direction (the X direction). See FIGS. 3 and 4A . When viewed from a plane, the length of the first venting passage 1251 along the first direction (the X direction) may be longer than the length of the first venting passage 1251 along the second direction (the Y direction).

[0057] In an exemplary embodiment, the arrangement of the multiple protruding extensions 125p of the lower cover plate 125 may correspond to the arrangement of the multiple first venting passages 1251. The multiple protruding extensions 125p may be arranged in the second direction (Y direction) and spaced apart from each other in the second direction (Y direction). The multiple protruding extensions 125p may each be below a corresponding first venting passage 1251. Within the protruding extensions 125p, the second venting passages 1253 extend in the horizontal direction (e.g., X direction), and the outlets of the second venting passages 1253 may be located on the sides of the protruding extensions 125p along the horizontal direction (e.g., X direction).

[0058] 4B, the second venting passage 1253 of the protruding extension 125p may extend in a first direction (X direction) and have one outlet on a side of the protruding extension 125p along the first direction (X direction). In this case, gas originating from the cell block 110 is discharged to the free volume FV (first space) of the pack housing 501 through the outlet of the second venting passage 1253, and the gas discharged through the outlet of the second venting passage 1253 generally flows in the first direction (X direction), which is the extension direction of the second venting passage 1253. However, the direction and arrangement of the exhaust passages of the present invention are not limited thereto.

[0059] The side cover plates 123 may be disposed on one side and the other side of the cell blocks 110. For example, one of the side cover plates 123 may extend along a first side of all the cell blocks 110 provided in the battery cell assembly 100, and the other of the side cover plates 123 may extend along a second side of all the cell blocks 110 provided in the battery cell assembly 100.

[0060] In the illustrative embodiment, the battery cell assembly 100 may have a side mounting structure that is fastened to the pack housing 501 via a side cover plate 123. In this case, the side cover plate 123 may include a fastening portion 1231 that is fastened to the pack housing 501, on which the battery cell assembly 100 is mounted, via a fastening member such as a bolt. The fastening portion 1231 may include a fastening hole H1 into which the bolt is fastened.

[0061] In another exemplary embodiment, the battery cell assembly 100 may have a mounting structure in which its upper end is directly fastened to the pack housing 501, in which case the above-mentioned fastening portion 1231 of the side cover plate 123 may be omitted.

[0062] Fig. 5 is a cross-sectional view showing a battery pack 500 according to an exemplary embodiment of the present invention. Fig. 6 is a cross-sectional view showing an example of the operation of the battery pack 500. In the following, descriptions that overlap with those described above will be omitted or simplified.

[0063] 5, a battery pack 500 may include a pack housing 501 and a battery cell assembly 100 mounted in the pack housing 501. The battery pack 500 may include one or more battery cell assemblies 100 mounted in the pack housing 501. In an exemplary embodiment, the battery pack 500 may include two or more battery cell assemblies 100 arranged in a first direction (X direction).

[0064] The pack housing 501 may include a housing 510 having an accommodation space in which the battery cell assemblies 100 are accommodated, and a pack cover 520 coupled to the housing 510 to cover the housing 510 in which the battery cell assemblies 100 are accommodated. The accommodation space of the housing 510 may be defined by a bottom wall 511 facing the lower surfaces of the cell blocks 110 of the individual battery cell assemblies 100, and side walls 513 located on the edges of the bottom wall 511. When the battery pack 500 is mounted on a vehicle, a passenger compartment where passengers sit may be located above the pack cover 520, and the ground on which the vehicle runs may be located below the housing 510.

[0065] In an exemplary embodiment, the battery cell assembly 100 may be secured to and supported by the pack cover 520. In other exemplary embodiments, the battery cell assembly 100 may be secured to the housing 510 via fasteners such as bolts.

[0066] A free volume FV (first space) may be provided between the lower surface of the battery cell assembly 100 and the bottom wall 511 of the housing 510. The free volume FV may be understood as a space formed when the bottom wall 511 of the housing 510 and the individual battery cell assemblies 100 are spaced apart from each other. In this specification, the free volume FV (first space) may also be referred to as a venting space or a buffer space.

[0067] The free volume FV may be in communication with the venting passage 125v of the lower cover plate 125. For example, as shown in FIG. 7, the free volume FV (first space) may form a venting path VP (see FIG. 7) together with the venting passage 125v of the lower cover plate 125, through which high-temperature gas or flame generated by the battery cell assembly 100 inside the battery pack 500 is discharged. For example, high-temperature gas or flame generated by the battery cell 111 may flow into the free volume FV through the venting passage 125v of the lower cover plate 125, move laterally within the pack housing 501, and then flow to the exhaust section. For example, there may be an exhaust device 530 (e.g., FIG. 7) connected to one side of the pack housing 501. The exhaust device 530 may include a path (e.g., an exhaust channel) for discharging gas and / or heat inside the battery pack 500. When the battery cell assembly 100 is in a thermal runaway state, the exhaust device 530 can slow thermal propagation by releasing gas and / or heat inside the battery pack 500 to the outside. The venting passage 125v of the lower cover plate 125 can direct high-temperature gas originating from the cell block 110 in a predetermined direction (e.g., toward the exhaust device 530). In this case, the free volume FV (first space) and the venting passage 125v function as a directional venting passage during a thermal runaway event, thereby protecting passengers from the thermal runaway event.

[0068] Furthermore, the upper surface of the battery cell assembly 100 may be tightly coupled to the lower surface of the pack cover 520. If there is a space between the battery cell assembly 100 and the pack cover 520, high-temperature gas may be introduced into the space between one battery cell assembly 100 and the pack cover 520 during a thermal runaway event, and heat and flame may propagate to other adjacent battery cell assemblies 100. Heat and flame may also be transferred to the pack cover 520, potentially affecting the passenger space above the pack cover 520. According to the embodiment, because the upper surface of the battery cell assembly 100 and the lower surface of the pack cover 520 are tightly coupled, gas or flame generated from the battery cell assembly 100 may be guided to the vent passage 125v and the free volume FV (first space).

[0069] Also, as shown in FIG. 6 , when a strong external impact ES is applied to the battery pack 500 due to foreign objects flying onto the underside of the vehicle while driving on a hard surface such as an unpaved road, the free volume FV (first space) can absorb or buffer the external impact. Therefore, damage to the battery cell assemblies 100 caused by the impact can be prevented. The free volume FV (first space) is an empty space between each of the battery cell assemblies 100 and the housing 510. When the housing 510 deforms toward the battery cell assembly 100 due to an impact applied to the underside of the vehicle, the free volume FV can be used as a space that allows some degree of freedom in allowing deformation of the housing 510. The free volume FV does not need to have any other structures installed. Alternatively, structures that support the battery cell assemblies 100 and the like can be installed partially within the free volume FV. When a structure is installed within the free volume FV, a space large enough to allow deformation of the housing 510 must be provided between the battery cell assemblies 100 and the housing 510.

[0070] The height of the free volume FV (first space) and the distance between the bottom wall 511 of the housing 510 and the battery cell assembly 100 may be set sufficiently to absorb external impacts. The height of the free volume FV may be determined taking into consideration the dimensions and rigidity of the vehicle frame, the dimensions and rigidity of the housing 510, the dimensions of the battery pack 500, the amount of gas generated and the rate of gas discharge during thermal runaway, and the like. For example, when the thickness or rigidity of the vehicle frame or the bottom wall 511 of the housing 510 is relatively large, at least one of the size and height of the free volume FV may be relatively small. Furthermore, when the thickness or rigidity of the vehicle frame or the bottom wall 511 of the housing 510 is relatively small, there is a high possibility of deformation of the bottom wall 511 of the housing 510. Therefore, to protect the battery cell assembly 100, at least one of the size and height of the free volume FV may be relatively increased. Furthermore, when the size of the battery pack 500 is relatively large according to the battery pack 500 specifications, a relatively large free volume FV may be ensured. If the size of the battery pack 500 is relatively small, the height of the free volume FV that can be ensured may be relatively low, and it may be necessary to relatively increase the thickness and rigidity of the bottom wall 511 of the housing 510. Also, if the height of the free volume FV is too low, the gas discharge path becomes small, and the internal pressure of the battery pack 500 may rise rapidly during thermal runaway. Therefore, the size and height of the free volume FV (first space) may be determined taking into account the amount of gas generated and the discharge speed.

[0071] The maximum height of the free volume FV (first space) may be determined depending on the degree of damage to the battery cells 111 included in the battery cell assembly 100. For example, if the damage tolerance limit of the battery cell 111 is 1 mm, the free volume FV may be determined so that the battery cell 111 does not deform more than 1 mm when the housing 510 deforms and presses the lower surface of the battery cell 111. In this case, the amount of deformation of the housing 510 may vary depending on the thickness and rigidity of the housing 510. Therefore, the size and height of the free volume FV may be determined in consideration of both the damage tolerance limit of the battery cell 111 and the thickness and rigidity of the housing 510.

[0072] According to an exemplary embodiment of the present invention, a free volume FV that functions as a buffer against external impact is provided between the bottom of the battery pack 500 (i.e., the bottom wall 511 of the housing 510) and the battery cell assembly 100, thereby preventing damage to the battery cell assembly 100 and / or the battery cells 111 due to external impact and ultimately improving the stability of the battery pack 500.

[0073] Furthermore, according to an exemplary embodiment of the present invention, the free volume FV and the vent passage 125v provided in the lower cover plate 125 of the battery cell assembly 100 together form a directional vent passage within the battery pack 500, and high-temperature gas or flames within the battery pack 500 can be discharged to the outside of the battery pack 500 through the directional vent passage. This can protect passengers in a thermal runaway event and improve the safety of the battery pack 500.

[0074] 6 , the lower cover plate 125 can prevent damage to the battery cell assembly 100 when an external impact ES is applied to the battery pack 500. For example, even if the amount of deformation of the bottom wall 511 of the pack housing 501 due to the external impact ES exceeds the height of the free volume FV (first space) provided in the pack housing 501, the protruding extension 125p of the lower cover plate 125 can function as a protective member that protects the cell block 110, thereby improving the safety of the battery pack 500.

[0075] 7 is a cross-sectional view showing a battery pack 500A according to an exemplary embodiment of the present invention. In the following, descriptions that overlap with those described above will be omitted or simplified.

[0076] Referring to FIG. 7, a battery pack 500A may include a pack housing 501 and a plurality of battery cell assemblies 100 mounted in the pack housing 501.

[0077] A plurality of battery cell assemblies 100 may be mounted in the pack housing 501 so as to be arranged in a first direction (X direction). In FIG. 7, the battery pack 500A is illustrated as including four battery cell assemblies 100 arranged in the first direction (X direction), but this is not limiting. For example, the battery pack 500A may include two or more battery cell assemblies 100 arranged in the first direction (X direction).

[0078] The plurality of battery cell assemblies 100 may have a side mounting structure in which they are fastened to support blocks 515 of the pack housing 501 via side cover plates 123 provided on both sides of each of the battery cell assemblies 100. More specifically, support blocks 515 may be provided on the bottom wall 511 of the pack housing 501, and fastening portions 1231 provided on the side cover plates 123 of each battery cell assembly 100 may be fastened to corresponding ones of the support blocks 515 via fastening members such as bolts.

[0079] According to an exemplary embodiment of the present invention, the plurality of battery cell assemblies 100 in the battery pack 500A are fastened to the pack housing 501 using a side mounting method, thereby reducing damage caused by swelling of the battery cells 111 and improving the structural safety of the plurality of battery cell assemblies 100.

[0080] 8 is a cross-sectional view showing a battery pack 500B according to an exemplary embodiment of the present invention. In the following, descriptions that overlap with those described above will be omitted or simplified.

[0081] Referring to FIG. 8 , a battery pack 500B may include a pack housing 501 and a battery cell assembly 100 mounted in the pack housing 501. The battery cell assembly 100 may be in contact with the lower surface of a pack cover 520. For example, the battery cell assembly 100 may be adhered to the lower surface of the pack cover 520 by a second thermally conductive adhesive layer 531 interposed between the battery cell assembly 100 and the pack cover 520. For example, the second thermally conductive adhesive layer 531 may include a thermally conductive material (TIM). The second thermally conductive adhesive layer 531 may prevent an air gap from forming between the individual battery cell assemblies 100 and the pack cover 520. The second thermally conductive adhesive layer 531 may be configured to transfer heat between the battery cell assembly 100 and the pack cover 520. Therefore, heat from the battery cell assembly 100 may be dissipated to the pack cover 520 side through the second thermally conductive adhesive layer 531.

[0082] If the pack cover 520 is provided with an appropriate cooling device, heat from the battery cell assembly 100 can be transferred to the cooling device via the second thermally conductive adhesive layer 531. The cooling device can include, for example, a second cooling channel 521 provided in the pack cover 520 and through which a cooling fluid flows. If the second cooling channel 521 is provided in the pack cover 520, the first cooling channel (1211 in FIG. 5) provided in the upper cover plate 121 can be omitted. However, the present invention is not limited thereto. If both the first cooling channel 1211 and the second cooling channel 521 are used in the battery pack, the cooling fluids in the first cooling channel and the second cooling channel can be the same or different. The second thermally conductive adhesive layer 531 is disposed between the upper surface of each battery cell assembly 100 and the pack cover 520, and the second cooling channel 521 is provided in the pack cover 520, so that the battery cell assembly 100 can be cooled.

[0083] Fig. 9A is a cross-sectional view showing a battery pack 500C according to an exemplary embodiment of the present invention. Fig. 9B is a perspective view showing a lower cover plate 125A of the battery cell assembly 100 shown in Fig. 9A. In the following, descriptions that overlap with those described above will be omitted or simplified.

[0084] 9A and 9B, in the battery cell assembly 100 of the battery pack 500C, the lower cover plate 125A may have a generally flat plate shape. The lower cover plate 125A includes venting passages 125v that vertically penetrate the lower cover plate 125A, and the venting passages 125v may each communicate with the free volume FV (first space). The lower cover plate 125A illustrated in FIGS. 9A and 9B may be substantially the same as or similar to the lower cover plate 125 described with reference to FIGS. 1 to 4B from which the protruding extensions 125p have been removed.

[0085] FIG. 10 is a schematic diagram illustrating an electric mobile device 1000 (eg, an electric vehicle) equipped with a battery pack 1100 according to an exemplary embodiment of the present invention.

[0086] 10, for simplicity of illustration, only the vehicle body frame 1200 that forms the lower skeleton of the vehicle, the battery pack 1100 coupled to the vehicle body frame 1200, and tires are shown. The battery pack 1100 may include battery packs 500, 500A, 500B, and 500C described with reference to FIGS. 5, 7, 8, and 9A.

[0087] In a typical battery pack, a battery cell assembly is installed at the bottom of the pack housing of the battery pack. However, in this embodiment, the battery cell assembly 100 of the battery pack 1100 may be supported by the pack cover 520 of the pack housing, and a space may be provided below the battery cell assembly 100. That is, there is no space between the battery cell assembly 100 and the pack cover 520, preventing gas generated in the battery cell assembly 100 from being transmitted to the passenger space above the vehicle. The gas and / or flame is guided to a first space (free volume FV, see FIG. 5) provided between the battery cell assembly 100 and the pack housing of the battery pack 1100. The gas and / or flame flows through the first space (free volume FV) and is exhausted to the underside of the vehicle through a gas exhaust section installed in the battery pack 1100, for example, exhaust device 530 (FIG. 7). In one embodiment of the present invention, the gas exhaust section may be located on a side of the housing toward the rear of the electric mobile device. In one embodiment of the present invention, the gas exhaust part may include a relief valve and / or a burst valve. Also, according to this embodiment, a free volume FV is provided between the battery cell assembly 100 and the pack housing in the battery pack 1100, so that even if the pack housing is deformed, the battery cell assembly 100 can be prevented from being damaged.

[0088] According to an embodiment of the present invention, the battery pack 1100 and the electric vehicle 1000 (e.g., an electric vehicle) equipped with the battery pack 1100 can enhance passenger safety, protect the battery cell assembly 100, which is a core component, and improve the durability of the battery pack 1100 and the electric vehicle 1000.

[0089] The present invention has been described in more detail above through the drawings and embodiments, etc. However, the configurations shown in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0090] 100: Battery cell assembly 110: Cell Block 111: Battery cell 120: Case 121: Upper cover plate 123: Side cover plate 125: Lower cover plate 125v: Venting passage 500: Battery pack 510: Housing 520: Pack cover

Claims

1. a battery cell assembly including a cell block including a plurality of battery cells and a lower cover plate connected to a lower surface of the cell block; a housing having an opening and configured to accommodate the battery cell assembly; a pack cover coupled to the housing and covering the opening, The battery cell assembly and the bottom wall of the housing are spaced apart to form a first space; The lower cover plate includes a venting passage communicating with the first space.

2. the lower cover plate includes a protruding extension portion that protrudes toward the first space and extends in a first direction along the lower surface of the cell block, The battery pack according to claim 1 , wherein the venting passage includes a portion extending in the first direction within the protruding extension.

3. The lower cover plate is a main plate facing the lower surface of the cell block; a protruding extension extending in a first direction along the lower surface of the cell block below the main plate, The venting passage is a first venting passage extending vertically through the main plate; 2. The battery pack of claim 1, further comprising: a second venting passage extending in the first direction within the protruding extension and having an inlet connected to the first venting passage and an outlet connected to the first space.

4. The first venting passage extends vertically, The battery pack according to claim 3 , wherein the second venting passage extends horizontally.

5. the battery cell assembly further includes an upper cover plate on an upper surface of the cell block; The battery pack according to claim 1 , wherein the upper cover plate includes a first cooling channel configured to allow a first cooling fluid to flow therethrough.

6. The battery pack of claim 5 , wherein the battery cell assembly further comprises a first thermally conductive adhesive layer interposed between the upper cover plate and the cell block.

7. The battery pack according to claim 1 , wherein the battery cell assembly is fixed to the pack cover.

8. 8. The battery pack according to claim 7, wherein the pack cover includes a second cooling channel configured to allow a second cooling fluid to flow therethrough.

9. The battery pack according to claim 8 , further comprising a second thermally conductive adhesive layer interposed between the battery cell assembly and the pack cover.

10. The battery cell assembly further includes a side cover plate on one side of the cell block, The battery pack according to claim 1 , wherein the side cover plate is fastened to the housing.

11. the battery cell assembly further includes side cover plates spaced apart from each other, the cell block being disposed between the side cover plates; The battery pack according to claim 1 , wherein the side cover plates are fixed to other support blocks provided on the housing.

12. The battery pack according to claim 11 , wherein the plurality of battery cells are pouch-type battery cells, and a sealed portion of a pouch in the pouch-type battery cell faces the first space.

13. The battery pack according to claim 1 , wherein each of the plurality of battery cells is a cylindrical battery cell or a prismatic battery cell and includes a vent.

14. The battery pack according to claim 13 , wherein the venting portion of the cylindrical battery cell or the prismatic battery cell faces the first space.

15. a battery cell assembly including a cell block having a plurality of battery cells and a lower cover plate below a lower surface of the cell block; a housing having an opening and configured to accommodate the battery cell assembly; a pack cover coupled to the housing and covering the opening, the battery cell assembly and a bottom wall of the housing are spaced apart from each other to form a first space; an electric mobile device, comprising a battery pack, wherein the lower cover plate includes a venting passage communicating with the first space;

16. 16. The electric mobility device of claim 15, wherein the electric mobility device is an electric vehicle.

17. The electric mobile device of claim 15 , wherein the battery pack further includes an exhaust port in communication with the first space.

18. 18. The electromobile device of claim 17, wherein the exhaust is located on a side of the housing opposite a rear face of the electromobile device.

19. a battery cell assembly including a cell block having a plurality of battery cells, an upper cover plate on an upper surface of the cell block, a lower cover plate under a lower surface of the cell block, a side cover plate on at least one side of the cell block, and a first thermally conductive adhesive layer between the upper cover plate and the cell block; a housing having an opening and configured to accommodate the battery cell assembly; a pack cover coupled to the housing and covering the opening; a second thermally conductive adhesive layer between the battery cell assembly and the pack cover; the battery cell assembly and the bottom wall of the housing are spaced apart to form a first space; the lower cover plate includes a venting passage communicating with the first space; the upper cover plate includes a first cooling channel configured to pass a first cooling fluid therethrough; The battery pack, wherein the pack cover includes a second cooling channel configured to pass a second cooling fluid therethrough.

20. The battery pack according to claim 19 , further comprising an exhaust portion in communication with the first space.

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