Battery pack

Abstract

According to an exemplary embodiment of the present invention, a battery pack is provided, the battery pack including a housing, and a first battery assembly and a second battery assembly disposed on an upper surface of a plate portion of the housing, each of the first battery assembly and the second battery assembly including a cell stack and a first cross beam and a second cross beam spaced apart from each other with the cell stack interposed therebetween, the first cross beam of the second battery assembly has a shape different from and complementary to the second cross beam of the first battery assembly, and the first cross beam of the second battery assembly is spaced apart from the second cross beam of the first battery assembly.

Description

[Technical field]

[0001] The present invention relates to a battery pack. This application claims the benefit of Korean Application No. 10-2022-0168184, filed on December 5, 2022, and Korean Application No. 10-2023-0029863, filed on March 7, 2023, which are hereby incorporated by reference in their entireties. [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, the manufacturing cost per unit capacity of secondary batteries has dramatically decreased due to improvements in energy density and economies of scale, and as the driving range of BEVs (battery electric vehicles) increases to a level comparable to that of fuel-powered vehicles, the main use of secondary batteries is shifting from mobile devices to mobility.

[0003] The trend in technological development of secondary batteries for mobility is to improve energy density and safety. Here, the energy density of a secondary battery is the maximum electrical energy that can be stored in the secondary battery divided by the mass of the secondary battery. Since a high energy density of a secondary battery is directly linked to the driving efficiency and driving range of mobility, various researches are being conducted to improve the energy density of secondary batteries. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a battery pack having improved energy density. [Means for solving the problem]

[0005] According to an exemplary embodiment of the present invention for solving the above-mentioned problems, a battery pack is provided, the battery pack includes a housing including a plate portion, and a first battery assembly and a second battery assembly including a plurality of battery cells arranged on an upper surface of the plate portion of the housing, each of the first battery assembly and the second battery assembly including a cell stack and a first cross beam and a second cross beam spaced apart from each other with the cell stack interposed therebetween, the first cross beam of the second battery assembly has a shape different from and complementary to the second cross beam of the first battery assembly, the first cross beam of the second battery assembly faces the second cross beam of the first battery assembly, and the first cross beam of the second battery assembly is spaced apart from the second cross beam of the first battery assembly.

[0006] The battery further includes a heat insulator interposed between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

[0007] An air gap is provided between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

[0008] The first cross beam of each of the first and second battery assemblies includes a first plate covering a first side of the cell stack, a second plate spaced apart from the cell stack with the first plate interposed therebetween, and a first rib and a second rib connected to each of the first and second plates and interposed between the first and second plates.

[0009] The second cross beam of each of the first and second battery assemblies includes a third plate covering a second side of the cell stack, the second side being opposite to the first side, a fourth plate spaced apart from the cell stack with the third plate therebetween, and a third rib and a fourth rib connected to the third and fourth plates, respectively, and interposed between the third and fourth plates.

[0010] The first plate, the second plate, the third plate, the fourth plate, and the first rib, the second rib, the third rib, and the fourth rib each have a thickness of 10 mm or less.

[0011] Each of the first rib, the second rib, the third rib and the fourth rib includes a plurality of slots.

[0012] The plurality of slots in each of the first rib, the second rib, the third rib and the fourth rib overlap each other.

[0013] The first battery assembly and the second battery assembly are spaced apart from each other in a first direction.

[0014] The length of the slot in the first direction is greater than the length in a second direction perpendicular to the first direction.

[0015] The battery further includes a heat insulator interposed between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

[0016] The insulation material contacts the first plate, the second plate, the third plate, the fourth plate, and the second rib and the third rib.

[0017] The battery further includes a plurality of fixing devices for fixing the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

[0018] The plurality of fixing members penetrate the insulation material.

[0019] The battery further includes a heat insulator interposed between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

[0020] The insulating material is in contact with the second plate and the third plate, and is spaced apart from one of the second rib and the third rib.

[0021] An air gap is provided between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

[0022] The battery assembly further includes an insulating material interposed between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly, the insulating material being spaced apart from one of the second plate and the third plate, and the insulating material being in contact with the second rib and the third rib. Effect of the Invention

[0023] A battery pack according to an exemplary embodiment of the present invention includes a battery assembly including a cross beam constructed of plates and ribs of about 10 mm or less, which increases the energy density of the battery pack.

[0024] Effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure belong from the following description. That is, 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 description of the drawings]

[0025] [Figure 1] FIG. 2 is a perspective view illustrating a battery pack according to an exemplary embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line 1I-1I' in FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing the first cross beam of FIG. 2. [Figure 4] FIG. 3 is a plan view showing the first cross beam of FIG. 2. [Diagram 5] FIG. 3 is a cross-sectional view showing the second cross beam of FIG. 2. [Figure 6] FIG. 3 is a plan view showing the second cross beam of FIG. 2. [Figure 7] The corresponding part in FIG. 2 is shown. [Figure 8] The corresponding part in FIG. 2 is shown. [Figure 9] The corresponding part in FIG. 2 is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Before 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 concept of the term to best describe his own invention.

[0027] Therefore, the embodiment described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent 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.

[0028] In addition, 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.

[0029] Since the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown roughly for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0030] (First embodiment) FIG. 1 is a perspective view illustrating a battery pack according to an exemplary embodiment.

[0031] FIG. 2 is a cross-sectional view taken along line 1I-1I' of FIG.

[0032] FIG. 3 is a cross-sectional view showing the first cross beam of FIG.

[0033] FIG. 4 is a plan view showing the first cross beam of FIG.

[0034] FIG. 5 is a cross-sectional view showing the second cross beam of FIG.

[0035] FIG. 6 is a plan view showing the second cross beam of FIG.

[0036] 1 to 6, a battery pack 100 may include a housing 110, a plurality of battery assemblies 120, a center beam 130, and a plurality of exhaust devices 140. The battery pack 100 is the final form of a battery system to be mounted on a mobility device or the like.

[0037] The housing 110 may provide a space for disposing multiple battery assemblies 120. The housing 110 may include a plate portion 111 and a side wall 110S.

[0038] The plate portion 111 may include an upper surface 111U and a lower surface 111L that are substantially parallel to each other. Two directions that are substantially parallel to the upper surface 111U of the plate portion 111 are defined as the X direction and the Y direction, and a direction that is substantially perpendicular to the upper surface 111U of the plate portion 111 is defined as the Z direction. Each of the X direction, the Y direction, and the Z direction may be substantially perpendicular to each other. Unless otherwise stated, the definitions of the directions are the same for the following drawings.

[0039] According to an exemplary embodiment, the plate portion 111 may include multiple plates welded together by friction stir welding. When the plate portion 111 is provided by friction stir welding, the plate portion 111 may include an interface between different plates. According to an exemplary embodiment, the plate portion 111 may also be comprised of a single plate.

[0040] The plate portion 111 may include a plurality of cooling channels that are flow paths for a cooling fluid. The plate portion 111 may include a plurality of cavities for reducing the weight of the plate portion 111. Each of the plurality of cooling channels and the plurality of cavities may extend in the X direction.

[0041] The side wall 110S may be coupled to the plate portion 111. The side wall 110S may extend in the Z direction. The side wall 110S may include an internal empty space, which may reduce the weight of the side wall 110S.

[0042] The multiple battery assemblies 120 may be disposed on an upper surface 111U of the plate portion 111 of the housing 110. The plate portion 111 may support the multiple battery assemblies 120. The side wall 110S may surround the multiple battery assemblies 120 horizontally.

[0043] Hereinafter, the technical idea of ​​the present invention will be described with reference to an embodiment in which the battery pack 100 is of a moduleless type and each of the plurality of battery assemblies 120 does not include a module frame. However, this is a non-limiting example and does not limit the technical idea of ​​the present invention in any way. Those skilled in the art can easily arrive at a plurality of battery assemblies including a module frame and a module-type battery pack including the same based on what is described herein.

[0044] Each of the battery assemblies 120 may include a cell stack 121, a plurality of separators, a first cross beam 125a, and a second cross beam 125b. The cell stack 121 may include a plurality of battery cells. Each of the battery assemblies 120 may further include a bus bar plate.

[0045] A battery cell is the basic unit of a lithium-ion battery, i.e. a secondary battery. A battery cell includes an electrode assembly, an electrolyte, and a case. Battery cells are classified into lithium-ion batteries, lithium-ion polymer batteries, and lithium polymer batteries depending on the configuration of the electrode assembly and electrolyte. Lithium-ion polymer batteries are easy to manufacture, have a low possibility of electrolyte leakage, and increase their occupancy rate within secondary batteries.

[0046] The battery cell 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.

[0047] The electrode assembly housed in the battery case includes a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes. Electrode assemblies are classified into a jelly roll type and a stack type according to the assembly form. The jelly roll type is formed by winding up a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes. The stack type includes a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators interposed between the positive and negative electrodes, which are stacked in sequence.

[0048] According to an exemplary embodiment, the battery cells of the cell stack 121 may be connected in series and / or parallel. As an example, the battery cells may be connected in series with each other. As another example, the battery cells may be connected in parallel with each other. As another example, the cell stack 121 may include a plurality of banks connected in series in parallel with each other, each of the plurality of banks including a plurality of battery cells connected in parallel with each other.

[0049] According to an exemplary embodiment, the cell stack 121 may further include a plurality of separators. The plurality of separators may prevent swelling of the plurality of battery cells by supporting the plurality of battery cells horizontally. According to an exemplary embodiment, the plurality of separators may be thermal barriers. According to an exemplary embodiment, each of the plurality of separators may have a high melting temperature and a low thermal conductivity. According to an exemplary embodiment, each of the plurality of separators may include a fire-retardant material, such as a ceramic and a coated glass material. According to an exemplary embodiment, the plurality of separators may also be configured to release a fire retarding material and a fire extinguishing agent in the event of a thermal runaway event.

[0050] The first cross beam 125a and the second cross beam 125b of each of the multiple battery assemblies 120 may be spaced apart from each other with the cell stack 121 therebetween. The first cross beam 125a and the second cross beam 125b may cover the cell stack 121. The first cross beam 125a and the second cross beam 125b may be fixed to the cell stack 121 by an adhesive or the like.

[0051] The first cross beam 125a of each of the plurality of battery assemblies 120 may include plates P1a, P2a and ribs R1a, R2a, R3a, R4a. The plates P1a, P2a may be substantially perpendicular to the X direction. The plates P1a, P2a may be spaced apart from each other in the X direction. The plate P1a may contact the cell stack 121. The plate P1a may cover a first side surface 121S1 of the cell stack 121. The plate P2a may be spaced apart from the cell stack 121 with the plate P1a therebetween. The length of the plate P1a in the Z direction may be longer than the length of the plate P2a in the Z direction.

[0052] The ribs R1a, R2a, R3a, R4a may be substantially perpendicular to the Z direction. The ribs R1a, R2a, R3a, R4a may be spaced apart from one another in the Z direction. The ribs R1a, R2a, R3a, R4a may be interposed between the plates P1a, P2a. The ribs R1a, R2a, R3a, R4a may be connected to the plates P1a, P2a. The ribs R3a, R4a may be interposed between the ribs R1a, R2a.

[0053] Each of the ribs R1a, R2a, R3a, and R4a may include a plurality of slotted holes SLa. The length of each of the plurality of slotted holes SLa in the X direction may be longer than the length of each of the plurality of slotted holes SLa in the Y direction. The plurality of slotted holes SLa of each of the ribs R1a, R2a, R3a, and R4a may overlap each other in the Z direction.

[0054] There may be empty spaces between the plates P1a, P2a and the ribs R1a, R2a, R3a, R4a, which may reduce the weight of the first cross beam 125a and improve the energy density of the battery pack 100. The plate P1a may also be referred to as a first plate, the plate P2a may also be referred to as a second plate, the rib R1a may also be referred to as a first rib, and the rib R2a may also be referred to as a second rib.

[0055] The second cross beam 125b of each of the plurality of battery assemblies 120 may include plates P1b, P2b and ribs R1b, R2b, R3b. The plates P1b, P2b may be substantially perpendicular to the X direction. The plates P1b, P2b may be spaced apart from each other in the X direction. The plate P1b may contact the cell stack 121. The plate P1b may cover a second side 121S2 of the cell stack 121. The second side 121S2 may be opposite to the first side 121S1. The plate P2b may be spaced apart from the cell stack 121 with the plate P1b therebetween. The length of the plate P1b in the Z direction may be longer than the length of the plate P2b in the Z direction.

[0056] The ribs R1b, R2b, R3b may be substantially perpendicular to the Z direction. The ribs R1b, R2b, R3b may be spaced apart from one another in the Z direction. The ribs R1b, R2b, R3b may be interposed between the plates P1b, P2b. The ribs R1b, R2b, R3b may be connected to the plates P1b, P2b. The rib R3b may be interposed between the ribs R1b, R2b.

[0057] Each of the ribs R1b, R2b, and R3b may include a plurality of long holes SLb. The length of each of the long holes SLb in the X direction may be longer than the length of each of the long holes SLb in the Y direction. The long holes SLb of each of the ribs R1b, R2b, and R3b may overlap with each other in the Z direction. The long holes SLb of each of the ribs R1b, R2b, and R3b may overlap with the long holes SLa of each of the ribs R1a, R2a, R3a, and R4a in the Z direction.

[0058] There may be empty spaces between the plates P1b, P2b and the ribs R1b, R2b, R3b, which may reduce the weight of the second cross beam 125b and improve the energy density of the battery pack 100. The plate P1b may also be referred to as a third plate, the plate P2b may also be referred to as a fourth plate, the rib R1b may also be referred to as a third rib, and the rib R2b may also be referred to as a fourth rib.

[0059] According to an exemplary embodiment, the second cross beam 125b of each of the plurality of battery assemblies 120 may be coupled to the first cross beam 125a of the subsequent plurality of battery assemblies 120. Thus, the lower portion of plate P1a may face plate P2b, the upper portion of plate P1b may face plate P2a, and rib R2a may face rib R1b.

[0060] The distance between the rib R3b and the plate portion 111 may be greater than the distance between the rib R2b and the plate portion 111. The distance between the rib R1b and the plate portion 111 may be greater than the distance between the rib R3b and the plate portion 111. The distance between the rib R2a and the plate portion 111 may be greater than the distance between the rib R1b and the plate portion 111. The distance between the rib R4a and the plate portion 111 may be greater than the distance between the rib R2a and the plate portion 111. The distance between the rib R3a and the plate portion 111 may be greater than the distance between the rib R4a and the plate portion 111. The distance between the rib R1a and the plate portion 111 may be greater than the distance between the rib R3a and the plate portion 111.

[0061] According to an exemplary embodiment, the thickness of each of the plates P1a, P2a, P1b, P2b and the ribs R1a, R2a, R3a, R4a, R1b, R2b, R3b may be about 10 mm or less. According to an exemplary embodiment, the thickness of each of the plates P1a, P2a, P1b, P2b and the ribs R1a, R2a, R3a, R4a, R1b, R2b, R3b may be about 10 mm or less, so that the first cross beam 125a and the second cross beam 125b may be light. According to an exemplary embodiment, the thickness of each of the plates P1a, P2a, P1b, P2b and the ribs R1a, R2a, R3a, R4a, R1b, R2b, R3b may be about 0.5 mm or more. According to an exemplary embodiment, the first cross beam 125a and the second cross beam 125b may have sufficient rigidity since the plates P1a, P2a, P1b, P2b and the ribs R1a, R2a, R3a, R4a, R1b, R2b, R3b each have a thickness of about 0.5 mm or more.

[0062] The insulating material 150 may be interposed between the second cross beam 125b of each of the plurality of battery assemblies 120 and the first cross beam 125a of the subsequent plurality of battery assemblies 120. The second cross beam 125b of each of the plurality of battery assemblies 120 and the first cross beam 125a of the subsequent plurality of battery assemblies 120 may be spaced apart in the X direction with the insulating material 150 therebetween. Thus, the plurality of battery assemblies 120 may be spaced apart in the X direction with the insulating material 150 therebetween.

[0063] The insulation 150 may contact the first cross beam 125a and the second cross beam 125b. The insulation 150 may contact the lower part of plate P1a, plate P2a, rib R2a, the upper part of plate P1b, plate P2b, and rib R2a.

[0064] The first cross beam 125a, the second cross beam 125b, and the insulation 150 may constitute a cross beam assembly CBA. The cross beam assembly CBA may extend in a direction perpendicular to the center beam 130 (i.e., the Y direction). The cross beam assembly CBA may isolate the cell stacks 121 in the X direction. The cross beam assembly CBA may be interposed between adjacent cell stacks 121.

[0065] The second cross beam 125b of each of the battery assemblies 120 and the first cross beam 125a of the subsequent battery assemblies 120 may be coupled by a mechanical fastener such as a bolt. The fastener may be coupled to the plate portion 111 by penetrating the long holes SLa of each of the ribs R1a, R2a, R3a, and R4a and the long holes SLb of each of the ribs R1b, R2b, and R3b. In this way, the second cross beam 125b of each of the battery assemblies 120 and the first cross beam 125a of the subsequent battery assemblies 120 may be fixed to each other. The fastener may penetrate the insulating material 150. In this way, the insulating material 150 may include a plurality of holes. The holes of the insulating material 150 may overlap the long holes SLa and SLb.

[0066] According to an exemplary embodiment, the first and second cross beams 125a, 125b may have different but complementary shapes relative to each other. The first and second cross beams 125a, 125b of each of the cross beam assemblies 125 may be interdigitated with each other.

[0067] The first cross beams 125a of the plurality of battery assemblies 120 arranged at both ends in the X direction may be coupled to a support disposed on the plate portion 111 of the housing 110. The first cross beams 125a and the support may be fixed by a fixing device.

[0068] The battery assemblies 120 may be arranged in the X and Y directions. In FIG. 1, the number of the battery assemblies 120 arranged in the X direction is three, and the number of the battery assemblies 120 arranged in the Y direction is two. Therefore, such an arrangement of the battery assemblies 120 can be said to be a 3*2 arrangement. A person skilled in the art can easily arrive at an arrangement of M*N battery assemblies 120 based on what is described herein, where M and N are each an integer greater than or equal to 2.

[0069] The center beam 130 may isolate elements disposed on the housing 110 from one another, thereby allowing the center beam 130 to protect the multiple battery assemblies 120 while simultaneously preventing unwanted short circuits therebetween.

[0070] The center beam 130 may extend between the opposing side walls 110S. The center beam 130 may extend in the X direction. The center beam 130 may contact any one of the side walls 110S. The center beam 130 may separate the multiple battery assemblies 120 from each other. The center beam 130 may be interposed between the multiple battery assemblies 120.

[0071] A plurality of exhaust devices 140 may be coupled to a portion of the side wall 110S. The side wall 110S may include an exhaust path connected to the plurality of exhaust devices 140. The plurality of exhaust devices 140 may be configured to retard thermal propagation by releasing high-temperature gas inside the battery pack 100 to the outside when at least one of the plurality of battery assemblies 120 is in a thermal runway state.

[0072] Here, thermal runaway of the battery assemblies 120 is a state in which the temperature change of the battery assemblies 120 accelerates the temperature change, and is an uncontrollable positive feedback. The battery assemblies 120 in the thermal runaway state exhibit a rapid temperature rise and emit a large amount of high-pressure gas and combustion debris.

[0073] The battery pack 100 may further include electrical components. The electrical components may be disposed on the housing 110. The electrical components may be disposed between a side wall 110S on which the exhaust device 140 is installed and the plurality of battery assemblies 120. The electrical components may include any electronic elements necessary to operate the battery pack.

[0074] 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 a specific node inside the multiple battery assemblies 120 and measuring the temperature at a set position inside the battery pack 100. The battery pack 100 may include instruments for measuring the voltage, current, and temperature described above.

[0075] Balancing the battery pack 100 is an operation that reduces the deviation between the multiple battery assemblies 120. Controlling the battery pack 100 includes preventing the occurrence of overcharging, over-discharging, and overcurrent. Through monitoring, balancing, and control, the battery pack 100 can operate under optimal conditions, thereby preventing a shortened life span of each of the multiple battery assemblies 120.

[0076] The electrical components may further include a cooling device, a power relay assembly (PRA), a safety plug, and the like. The cooling device may include a cooling fan. The cooling fan may prevent overheating of each of the multiple battery assemblies 120 by circulating air inside the battery pack 100. 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 may protect the multiple battery assemblies 120 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.

[0077] The battery pack 100 may further include a plurality of bus bars configured to electrically connect the plurality of battery assemblies 120. The plurality of battery assemblies 120 may be connected in series by the plurality of bus bars. In this manner, the battery pack 100 may be configured to output a high voltage to an external load (e.g., a vehicle motor).

[0078] The battery pack 100 may further include a lead plate coupled to the side wall 110S. The lead plate may cover elements disposed inside the battery pack 100, such as the battery assembly 120 and electrical components. The lead plate may be fixed to the battery pack 100 by a mechanical coupling means, such as a bolt.

[0079] Second embodiment Fig. 7 shows a portion corresponding to Fig. 2. Thus, the cross beam assembly CBAa shown in Fig. 7 can replace the cross beam assembly CBA in Fig. 2.

[0080] 7, the cross beam assembly CBAa may not include a thermal insulation material. This may provide an air gap AG between the first cross beam 125a and the second cross beam 125b, thereby reducing the weight of the cross beam assembly CBAa. The air gap AG between the first cross beam 125a and the second cross beam 125b may also function as a thermal insulation material.

[0081] Third embodiment Fig. 8 shows a portion corresponding to Fig. 2. Thus, the cross beam assembly CBAb shown in Fig. 8 can replace the cross beam assembly CBA in Fig. 2.

[0082] 3, 5 and 8, the insulation 151 of the cross beam assembly CBAb may have a smaller size than the insulation 150 of Fig. 2. This allows an air gap AG to be provided between the first cross beam 125a and the second cross beam 125b, and the weight of the cross beam assembly CBAb may be reduced.

[0083] More specifically, the heat insulating material 151 may contact the ribs R2a and R1b. The heat insulating material 151 may be separated from some of the plates P1a, P2a, P1b, and P2b. The heat insulating material 151 may be separated from any one of the plates P2a and P2b. This may provide an air gap AG between the plates P1a, P2a, P1b, and P2b.

[0084] (Fourth embodiment) Fig. 9 shows a portion corresponding to Fig. 2. Thus, the cross beam assembly CBAc shown in Fig. 9 can replace the cross beam assembly CBA in Fig. 2.

[0085] 3, 5 and 8, the insulation 152 of the cross beam assembly CBAc may have a smaller size than the insulation 150 of Fig. 2. This allows an air gap AG to be provided between the first cross beam 125a and the second cross beam 125b, and the weight of the cross beam assembly CBAc may be reduced.

[0086] More specifically, the heat insulating material 152 may be in contact with the plates P1a, P2a, P1b, and P2b, and may be spaced apart from one of the ribs R2a and R1b, so that an air gap AG may be provided between the ribs R2a and R1b.

[0087] The present invention has been described in more detail above through the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not fully represent 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]

[0088] 100 Battery Packs 110 Housing 111 Plate section 111L Bottom 111U top 110S side wall 120 Battery Assembly 121 Cell Stack 121S1 1st side 121S2 2nd side 125 Cross beam assembly 125a 1st Cross Beam 125b 2nd cross beam 130 Center Beam 140 Exhaust system 150 Insulation 151 Insulation 152 Insulation

Claims

1. a housing including a plate portion; a first battery assembly and a second battery assembly disposed on an upper surface of the plate portion of the housing and including a plurality of battery cells; and Each of the first battery assembly and the second battery assembly includes a cell stack and a first cross beam and a second cross beam spaced apart from each other with the cell stack therebetween; the first cross beam of the second battery assembly has a shape different from and complementary to the second cross beam of the first battery assembly; The first cross beam of the second battery assembly faces the second cross beam of the first battery assembly; and The first cross beam of the second battery assembly is spaced apart from the second cross beam of the first battery assembly.

2. 2. The battery pack of claim 1, further comprising a thermal insulator interposed between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

3. 2. The battery pack of claim 1, wherein an air gap is provided between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

4. The first cross beam of each of the first battery assembly and the second battery assembly includes: a first plate covering a first side of the cell stack; a second plate spaced apart from the cell stack with the first plate therebetween; a first rib and a second rib connected to the first plate and the second plate, respectively, and interposed between the first plate and the second plate; and The second cross beam of each of the first battery assembly and the second battery assembly includes: a third plate covering a second side of the cell stack, the second side being opposite the first side; a fourth plate spaced apart from the cell stack with the third plate therebetween; 2. The battery pack according to claim 1, further comprising: a third rib and a fourth rib coupled to the third plate and the fourth plate, respectively, and interposed between the third plate and the fourth plate.

5. 5. The battery pack according to claim 4, wherein each of the first plate, the second plate, the third plate, and the fourth plate, and the first rib, the second rib, the third rib, and the fourth rib has a thickness of 10 mm or less.

6. The battery pack according to claim 4 , wherein each of the first rib, the second rib, the third rib, and the fourth rib includes a plurality of slots.

7. The battery pack according to claim 6 , wherein the plurality of slots in each of the first rib, the second rib, the third rib, and the fourth rib overlap each other.

8. The first battery assembly and the second battery assembly are spaced apart from each other in a first direction, and The battery pack of claim 6 , wherein a length of the slot in the first direction is greater than a length of the slot in a second direction perpendicular to the first direction.

9. a heat insulating material interposed between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly; and 5. The battery pack of claim 4, wherein the insulation contacts the first plate, the second plate, the third plate, and the fourth plate, and the second rib and the third rib.

10. a plurality of fixing devices for fixing the first cross beam of the second battery assembly and the second cross beam of the first battery assembly; and The battery pack according to claim 9 , wherein the plurality of immobilizers penetrate the insulation material.

11. a heat insulating material interposed between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly, The insulating material is in contact with the second plate and the third plate, and The battery pack according to claim 4 , wherein the insulating material is spaced apart from one of the second rib and the third rib.

12. 12. The battery pack of claim 11, wherein there is an air gap between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly.

13. a heat insulating material interposed between the first cross beam of the second battery assembly and the second cross beam of the first battery assembly, The insulating material is spaced apart from one of the second plate and the third plate, and The battery pack according to claim 4 , wherein the insulating material contacts the second rib and the third rib.

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