Battery pack

Abstract

Exemplary embodiments provide a battery pack. The battery pack includes: a base plate; a plurality of battery cell assemblies located on the bottom plate; an intermediate beam located between the plurality of battery cell assemblies; the fireproof layer is coated on the middle beam, and the fireproof layer comprises a foamable fireproof material.

Description

Technical Field

[0001] The present disclosure relates to a battery pack. This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0088246, filed on Jul. 7, 2023, the entire contents of which are incorporated herein by reference. Background Art

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries have been widely used as energy sources for various types of wireless devices such as mobile phones, laptops, and cordless vacuum cleaners. Recently, as the manufacturing cost per unit capacity of secondary batteries has been significantly reduced due to increased energy density and economies of scale, and the cruising range of battery electric vehicles (BEVs) has increased to the same level as that of fuel vehicles, the main use of secondary batteries has shifted from mobile devices to mobility.

[0003] The trend of technical development of secondary batteries for mobile travel is the improvement of energy density and safety. The safety of secondary batteries for mobile travel is directly related to the lives of passengers and is therefore very important. When a thermal runaway event occurs, the safety of secondary batteries can be achieved through mechanical strength, reliability of electrical insulation, and delay of heat transfer. Summary of the invention

[0004] Technical issues

[0005] The present disclosure is directed to providing a battery pack with improved safety and energy density.

[0006] Technical Solution

[0007] An exemplary embodiment of the present disclosure provides a battery pack, which includes: a bottom plate; a plurality of battery cell assemblies located on the bottom plate; a middle beam located between the plurality of battery cell assemblies; and a fire-resistant layer coated on the middle beam, wherein the fire-resistant layer includes a foamable fire-resistant material.

[0008] Each of the plurality of battery cell assemblies may include a lead cover assembly, and the lead cover assembly of each of the plurality of battery cell assemblies may overlap the middle beam.

[0009] Each of the plurality of battery cell assemblies may include a lead cover assembly, and the lead cover assembly may include: a lead cover frame; and an integrated circuit mounted on the lead cover frame.

[0010] The foamable refractory material may be configured to form a foamed layer that is a heat-insulating carbonized layer when a thermal runaway event occurs in the battery pack.

[0011] The foamed layer may be porous.

[0012] The foaming layer may cover the lead cover assembly of each of the plurality of battery cell assemblies.

[0013] A refractory layer may cover the upper surface of the intermediate beam.

[0014] The fire-resistant layer may cover the upper surface and the side surfaces of the intermediate beam.

[0015] An exemplary embodiment provides a battery pack, which includes: a housing having a bottom plate and a side wall; a plurality of battery cell assemblies located on the bottom plate; a middle beam located between the plurality of battery cell assemblies; a cover plate coupled to the side wall; and a fire-resistant layer coated on the cover plate, wherein the fire-resistant layer includes a foamable fire-resistant material.

[0016] The refractory layer may overlap the intermediate beam.

[0017] The foamable refractory material may be configured to form a foamed layer that is a heat-insulating carbonized layer when a thermal runaway event occurs in the battery pack.

[0018] Each of the plurality of battery cell assemblies may include a lead cover assembly, and the lead cover assembly may include: a lead cover frame; and an integrated circuit mounted on the lead cover frame.

[0019] The foaming layer may cover the lead cover assembly of each of the plurality of battery cell assemblies.

[0020] Beneficial Effects

[0021] The battery pack according to the exemplary embodiment of the present disclosure includes a fire-resistant layer coated on the middle beam or the cover plate, the fire-resistant layer including a foamable fire-resistant material, thereby preventing the propagation of a thermal runaway event between adjacent battery cell assemblies and improving the safety of the battery pack.

[0022] The effects that can be achieved by the exemplary embodiments of the present disclosure are not limited to the above effects, and those skilled in the art to which the exemplary embodiments of the present disclosure belong will clearly derive and understand other effects not described herein from the following description. In other words, those skilled in the art can derive from the exemplary embodiments of the present disclosure the unexpected effects achieved when implementing the exemplary embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a top view of a battery pack according to an exemplary embodiment.

[0024] Figure 2 According to an exemplary embodiment, Figure 1 A cross-sectional view taken along line 1I-1I′.

[0025] Figure 3 is a cross-sectional view for describing an effect of a battery pack according to an exemplary embodiment.

[0026] Figure 4 is a cross-sectional view of a battery pack according to other exemplary embodiments.

[0027] Figure 5 is a cross-sectional view of a battery pack according to other exemplary embodiments.

[0028] Figure 6 is a cross-sectional view of a battery pack according to other exemplary embodiments. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before describing the embodiments of the present disclosure, the terms or expressions used in the present specification and claims should not be interpreted as limited to the terms or expressions generally understood or defined in a commonly used dictionary, but should be understood according to the meanings and concepts corresponding to the present disclosure based on the principle that the inventor of the present application can appropriately define the terms or expressions to best interpret the present disclosure.

[0030] Therefore, the embodiments described herein and the configurations shown in the accompanying drawings are merely examples of the present disclosure and do not reflect all technical concepts of the present disclosure. Therefore, it should be understood that various equivalents and modifications have been made to replace the configurations on the filing date of the present application.

[0031] When it is determined that well-known configurations or functions related to describing the present disclosure would obscure the subject matter of the present disclosure due to unnecessary details, such configurations or functions are not described in detail.

[0032] Since the embodiments of the present disclosure are provided to more fully explain the present disclosure to those skilled in the art, the shapes, sizes, etc. of the components shown in the drawings may be magnified, omitted, or schematically illustrated for clarity. Therefore, it should not be understood that the sizes or ratios of the components fully reflect their actual sizes or ratios.

[0033] (First embodiment)

[0034] Figure 1 1 shows a battery pack 100 according to an exemplary embodiment. Figure 1 , the cover plate 150 is omitted.

[0035] Figure 2 It is along Figure 1 A cross-sectional view taken along line 1I-1I′.

[0036] Figure 3 is a cross-sectional view illustrating the effect of the battery pack 100 according to an exemplary embodiment. More specifically, Figure 3 is with Figure 2 The figures correspond and illustrate the battery pack 100 when a thermal runaway event occurs.

[0037] Reference Figures 1 to 3 The battery pack 100 may include a housing 110 , a plurality of battery cell assemblies 120 , a middle beam 131 , a cross beam 133 , a fire-resistant layer 140 , and a cover plate 150 .

[0038] The case 110 may provide a space for mounting a plurality of battery cell assemblies 120 therein. The case 110 may include a bottom plate 111 and side walls 112 , 113 , 114 , and 115 .

[0039] Two directions substantially parallel to the upper surface 111U of the bottom plate 111 are defined as an X-axis direction and a Y-axis direction, and a direction substantially perpendicular to the upper surface 111U of the bottom plate 111 is defined as a Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction may be substantially perpendicular to each other. Unless otherwise specified, the definition of directions will apply to the following drawings.

[0040] The bottom plate 111 may include a plurality of plates that are friction stir welded to each other. The bottom plate 111 may include a plurality of cooling channels, a plurality of cavities, and ribs. Each of the cooling channels, cavities, and ribs may extend in the X-axis direction. The cooling channels may provide a path for the flow of a cooling fluid. The cooling channels may be spaced apart from each other in the Y-axis direction. The cooling channels may be arranged in the Y-axis direction. The plurality of cavities are hollow spaces formed in the bottom plate 111. By forming a plurality of cavities, the mass of the bottom plate 111 may be reduced, thereby improving the energy density of the battery pack 100. The ribs may define a plurality of cooling channels and a plurality of cavities. The ribs may surround a plurality of cooling channels and a plurality of cavities. The airtightness of the plurality of cooling channels and the plurality of cavities may be maintained by the ribs.

[0041] The side walls 112, 113, 114, and 115 may be joined to the bottom plate 111. The side walls 112, 113, 114, and 115 may be joined to the bottom plate 111 by, for example, friction stir welding.

[0042] The side walls 112 and 113 may be substantially perpendicular to the X-axis direction. The side walls 112 and 113 may be spaced apart from each other in the X-axis direction. The side walls 114 and 115 may be substantially perpendicular to the Y-axis direction. The side walls 114 and 115 may be spaced apart from each other in the Y-axis direction.

[0043] A plurality of battery cell assemblies 120 may be located on a bottom plate 111 of the housing 110. The bottom plate 111 may support the plurality of battery cell assemblies 120. Side walls 112, 113, 114, and 115 may horizontally surround the plurality of battery cell assemblies 120. The side walls 112, 113, 114, and 115 may protect the plurality of battery cell assemblies 120.

[0044] For example, the battery pack 100 may be a module-less battery pack, and each of the plurality of battery cell assemblies 120 may not include a module frame. As another example, the battery pack 100 may be a module-type battery pack, and each of the plurality of battery cell assemblies 120 may not include a module frame.

[0045] Each of the plurality of battery cell assemblies 120 may include a battery cell stack 121 and a lead cover assembly 123. The lead cover assembly 123 may be coupled to the battery cell stack 121.

[0046] Each battery cell stack 121 may include a plurality of groups connected in series to each other. Each of the plurality of groups may include one or more battery cells connected in parallel. The number of groups connected in series and the number of battery cells connected in parallel may be determined according to the voltage and current to be output from the battery cell stack 121 .

[0047] A plurality of battery cells are basic units of lithium-ion batteries (i.e., secondary batteries). Each of the plurality of battery cells includes an electrode assembly, an electrolyte, a housing, and an electrode lead. Each of the plurality of battery cells may be a cylindrical battery cell, a square battery cell, or a soft-pack battery cell. The electrode assembly of the cylindrical battery cell is embedded in a cylindrical metal can. The electrode assembly of the square battery cell is embedded in a square metal can. The electrode assembly of the soft-pack battery cell is embedded in a soft-pack housing including an aluminum laminate sheet.

[0048] The electrode assembly may include a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode. The electrode assembly may be a wound electrode assembly or a stacked electrode assembly. The wound electrode assembly may include a structure in which the positive electrode, the negative electrode, and a separator interposed therebetween are wound together. The stacked electrode assembly may include a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators interposed therebetween stacked in sequence.

[0049] The electrode lead may be joined to one of the positive electrode tabs of the plurality of positive electrodes and the negative electrode tabs of the plurality of negative electrodes. The electrode lead may be welded to one of the positive electrode tab and the negative electrode tab. The electrode lead may be an external connection terminal of each of the plurality of battery cells.

[0050] The lead cover assembly 123 may include a lead cover frame 123F and an integrated circuit 123C. For example, the lead cover assembly 123 may include a heat insulating material such as plastic. The lead cover assembly 123 may cover the electrode leads of the battery cell stack 121. Therefore, the lead cover assembly 123 may prevent an undesired short circuit between the electrode leads of the battery cell stack 121 and external elements. Examples of undesired short circuits between the electrode leads of the battery cell stack 121 and external elements include short circuits between electrode leads of adjacent battery cell assemblies 120.

[0051] The integrated circuit 123C may be mounted on the lead cover frame 123F. For example, the integrated circuit 123C may be fixed to the lead cover frame 123F by heat welding or the like. The integrated circuit 123C may be configured to detect the voltage of the electrode lead of the battery cell stack 121. The integrated circuit 123C may include a sensing plate or wire contacting the electrode lead of the battery cell stack 121. The integrated circuit 123C may include a temperature sensor.

[0052] The plurality of battery cell assemblies 120 may be arranged in the X-axis direction and the Y-axis direction. Figure 1 , the number of battery cell assemblies 120 arranged in the X-axis direction is three, and the number of battery cell assemblies 120 arranged in the Y-axis direction is two. Therefore, the array of multiple battery cell assemblies 120 can be a 3×2 array. Based on the above description, a person of ordinary skill in the art will be able to easily derive multiple battery cell assemblies 120 arranged in an M×N array (here, M and N are each an integer greater than 2).

[0053] The middle beam 131 may be located on the bottom plate 111. The middle beam 131 may extend in the X-axis direction. The middle beam 131 may be coupled to the bottom plate 111. The middle beam 131 may be welded to the bottom plate 111. Alternatively, the middle beam may be formed together with the bottom plate 111 by an extrusion process, and in this case may be included in the bottom plate 111.

[0054] The middle beam 131 may be interposed between the plurality of battery cell assemblies 120. The middle beam 131 may separate the plurality of battery cell assemblies 120 in the Y-axis direction. The plurality of battery cell assemblies 120 may be spaced apart from each other in the Y-axis direction, with the middle beam 131 interposed between the plurality of battery cell assemblies 120.

[0055] The cross beam 133 may be located on the bottom plate 111. The cross beam 133 may extend in the Y-axis direction. The cross beam 133 may be coupled to the bottom plate 111. The cross beam 133 may be welded to the bottom plate 111. In some cases, the cross beam 133 may be included in the battery cell assembly 120. In this case, the battery cell assembly 120 may be referred to as having a beam-integrated structure.

[0056] The cross beam 133 may be interposed between the plurality of battery cell assemblies 120 or may separate the electronic component mounting region EMR from the plurality of battery cell assemblies 120. The cross beam 133 may separate the plurality of battery cell assemblies 120 in the X-axis direction. The plurality of battery cell assemblies 120 may be spaced apart from each other in the X-axis direction, with the cross beam 133 interposed between the plurality of battery cell assemblies 120.

[0057] Figure 1The arrangement of the middle beam 131, the cross beam 133 and the plurality of battery cell assemblies 120 shown in the figure is a non-limiting example and should not be understood as limiting the technical concept of the present disclosure in any sense. According to the above description, a person skilled in the art will easily derive a battery pack including various numbers and arrangements of middle beams, cross beams and battery cell assemblies.

[0058] The middle beam 131 may be coated with a fire-resistant layer 140. The fire-resistant layer 140 may cover a side surface 131S of the middle beam 131. The fire-resistant layer 140 may cover an upper surface 131U of the middle beam 131.

[0059] The refractory layer 140 may include a foamable refractory material. Here, the foamable refractory material may be configured to have a foaming effect when heated. The foaming process may include melting the surface coating, foaming, expanding, generating a heat insulating layer, and generating a ceramic layer. The refractory layer 140 may be provided by a method such as spraying, coating, or spraying.

[0060] like Figure 3 As shown, when a thermal runaway event occurs inside the battery pack 100, the fire-resistant layer 140 can be configured to form a foaming layer 140F. The volume of the foaming layer 140F can be larger than the volume of the fire-resistant layer 140. The space between the frame 220 and the battery pack 100 can be filled with the foaming layer 140F. The foaming layer 140F can be a heat-insulating carbonized layer. The foaming layer 140F can be porous. The foaming layer 140F can have a high ignition point, a high melting point, and low thermal conductivity. Therefore, due to the foaming layer 140F, the flame generated in one battery cell assembly 120 can be prevented from propagating to an adjacent battery cell assembly 120.

[0061] The lead cover frame 123F includes an integrated circuit receiving portion for receiving the integrated circuit 123C, and thus the thickness of the upper portion of the lead cover frame 123F may be greater than the thickness of the lower portion of the lead cover frame 123F. Therefore, the middle beam 131 isolates only the lower portion of the battery cell assembly 120, and the upper portions of the battery cell assembly 120 may face each other without isolation.

[0062] Here, the upper and lower portions of the element may be defined with reference to the upper surface 111U of the bottom plate 111. For example, the upper portion of the element may be farther from the upper surface 111U of the bottom plate 111 than the lower portion thereof.

[0063] When a thermal runaway event occurs in the plurality of battery cell assemblies 120, the spaces between the battery cell assemblies 120 that are not covered by the middle beam 131 may be filled with the foaming layer 140F. Therefore, physical, thermal, and electrical insulation between the battery cell assemblies 120 may be improved, and the safety of the battery pack 100 may be improved.

[0064] Here, the thermal runaway state of the plurality of battery cell assemblies 120 is a state in which the temperature change of the plurality of battery cell assemblies 120 accelerates the temperature change, that is, runaway positive feedback. The temperature of the plurality of battery cell assemblies 120 in the thermal runaway state rises rapidly, and a large amount of high-pressure gas and burning fragments are discharged.

[0065] The cover plate 150 may be coupled to the side walls 112, 113, 114, and 115. The cover plate 150 may cover elements inside the battery pack 100, such as the battery cell assembly 120 and electronic components. The cover plate 150 may be fixed to the side walls 112, 113, 114, and 115 by a mechanical coupling device such as a fastening member.

[0066] The battery pack 100 may further include a venting device. For example, the venting device may be engaged with the side wall 112. The side wall 112 may include a vent hole, and the venting device may be engaged with the vent hole of the side wall 112. Each venting device may include a spring or a rupture disk. Each venting device may be configured to discharge gas from the interior of the battery pack 100 when the internal pressure of the battery pack 100 exceeds a threshold value.

[0067] The exhaust device may be configured to delay heat propagation by exhausting high-temperature gas from the inside of the battery pack 100 to the outside when at least one of the plurality of battery cell assemblies 120 is in a thermal runaway state.

[0068] The battery pack 100 may further include electronic components. The electronic components may be located on the electronic component mounting region EMR of the housing 110. The electronic components may include electronic devices required to drive the battery pack 100.

[0069] For example, the electronic components may include a battery management system (BMS). The BMS may be configured to monitor, balance, and control the battery pack 100. Monitoring of the battery pack 100 may include measuring voltage and current of certain nodes within the plurality of battery cell assemblies 120 and measuring the temperature of a set location in the battery pack 100. As described above, the battery pack 100 may include measuring instruments for measuring voltage, current, and temperature.

[0070] The balancing of the battery pack 100 is a work to reduce the deviation between the plurality of battery cell assemblies 120. The control of the battery pack 100 includes preventing overcharge, overdischarge and overcurrent. Through monitoring, balancing and control, the battery pack 100 can operate under optimal conditions, thereby preventing the life of each of the plurality of battery cell assemblies 120 from being shortened.

[0071] The electronic components may also include: a cooling device, a power relay assembly (PRA), a safety plug, etc. The cooling device may include a cooling fan. The cooling fan may circulate air in the battery pack 100 to prevent overheating of each of the multiple battery cell assemblies 120. The PRA may be configured to supply power to an external load (e.g., a motor of a vehicle) or cut off power supply from the high-voltage battery. When an abnormal voltage such as a voltage surge occurs, the PRA may cut off power supply to an external load (e.g., a motor of a vehicle) to protect the multiple battery cell assemblies 120 and the external load (e.g., a motor of a vehicle).

[0072] The battery pack 100 may further include a plurality of bus bars configured to be electrically connected to the plurality of battery cell assemblies 120. The plurality of battery cell assemblies 120 may be connected in series through the plurality of bus bars. Therefore, the battery pack 100 may be configured to output high voltage to an external load (eg, a motor of a vehicle).

[0073] (Second embodiment)

[0074] Figure 4 is a diagram for describing a battery pack 101 according to other exemplary embodiments.

[0075] Reference Figure 4 The battery pack 101 may include a housing 110, a plurality of battery cell assemblies 120, an intermediate beam 131, and a cross beam 133 (see Figure 1 ), fire-resistant layer 141 and cover plate 150.

[0076] The housing 110, the plurality of battery cell assemblies 120, the middle beam 131, the cross beam 133 (see Figure 1 ) and cover plate 150 as described above Figures 1 to 3 The contents described are substantially the same, and therefore, redundant descriptions thereof are omitted here.

[0077] The middle beam 131 may be coated with a fire-resistant layer 141. The fire-resistant layer 141 may include a foamable fire-resistant material. Therefore, when a thermal runaway event occurs inside the battery pack 101, the fire-resistant layer 141 may be configured to form a foaming layer 140F (see Figure 3 ).

[0078] The fire-resistant layer 141 may cover the upper surface 131U of the middle beam 131. The fire-resistant layer 141 may cover only the upper surface 131U of the middle beam 131. The fire-resistant layer 141 may not cover the side surface 131S of the middle beam 131. The fire-resistant layer 141 may be spaced apart from the side surface 131S of the middle beam 131.

[0079] According to an exemplary embodiment, since the fire-resistant layer 141 is only partially coated on the upper surface 131U of the middle beam 131 , the manufacturing cost of the battery pack 101 may be reduced, and the energy density of the battery pack 101 may be improved.

[0080] (Third Embodiment)

[0081] Figure 5 is a diagram for describing a battery pack 102 according to other exemplary embodiments.

[0082] Reference Figure 5 The battery pack 102 may include a housing 110, a plurality of battery cell assemblies 120, an intermediate beam 131, and a cross beam 133 (see Figure 1 ), fire-resistant layer 142 and cover plate 150.

[0083] The housing 110, the plurality of battery cell assemblies 120, the middle beam 131, the cross beam 133 (see Figure 1 ) and cover plate 150 as described above Figures 1 to 3 The contents described are substantially the same, and therefore, redundant descriptions thereof are omitted here.

[0084] The middle beam 131 may be coated with a fire-resistant layer 142. The fire-resistant layer 142 may include a foamable fire-resistant material. Therefore, when a thermal runaway event occurs inside the battery pack 102, the fire-resistant layer 142 may be configured to form a foaming layer 140F (see Figure 3 ).

[0085] The refractory layer 142 may cover the upper surface 131U of the middle beam 131. The refractory layer 142 may partially cover the side surface 131S of the middle beam 131. After coating and curing of the refractory layer 142, due to the flow of the refractory layer 142, a portion of the refractory layer 142 covering the side surface 131S of the middle beam 131 may be formed.

[0086] According to an exemplary embodiment, the fire-resistant layer 142 partially covers the middle beam 131 , so the manufacturing cost of the battery pack 102 may be reduced and the energy density of the battery pack 102 may be improved.

[0087] (Fourth embodiment)

[0088] Figure 6 is a diagram for describing a battery pack 103 according to other exemplary embodiments.

[0089] Reference Figure 6 The battery pack 103 may include a housing 110, a plurality of battery cell assemblies 120, an intermediate beam 131, and a cross beam 133 (see Figure 1 ), fire-resistant layer 143 and cover plate 150.

[0090] The housing 110, the plurality of battery cell assemblies 120, the middle beam 131, the cross beam 133 (see Figure 1 ) and cover plate 150 as described above Figures 1 to 3 The contents described are substantially the same, and therefore, redundant descriptions thereof are omitted here.

[0091] The cover plate 150 may be coated with a fire-resistant layer 143. The fire-resistant layer 143 may partially cover the cover plate 150. The fire-resistant layer 143 may include a foamable fire-resistant material. Therefore, when a thermal runaway event occurs inside the battery pack 103, the fire-resistant layer 143 may be configured to form a foaming layer 140F (see Figure 3 ). The fire-resistant layer 143 may overlap the middle beam 131 in the Z-axis direction. The fire-resistant layer 143 may overlap the lead cap assembly 123 of each of the plurality of battery cell assemblies 120 in the Z-axis direction.

[0092] The present disclosure has been described in more detail above with reference to the accompanying drawings, embodiments, etc. However, the configurations shown in the drawings or embodiments described in the present disclosure are merely embodiments of the present disclosure and do not reflect all technical concepts of the present disclosure, and therefore, it should be understood that various equivalents and modifications have been made to replace the configurations on the filing date of the present application.

Claims

1. A battery pack comprising: Base plate; A plurality of battery cell assemblies, wherein the plurality of battery cell assemblies are located on the bottom plate; A middle beam, the middle beam being located between the plurality of battery cell assemblies; as well as a fire-resistant layer, the fire-resistant layer being coated on the middle beam, Wherein, the refractory layer comprises a foamable refractory material.

2. The battery pack according to claim 1, wherein: Each of the plurality of battery cell assemblies includes a lead cover assembly, and The lead cover assembly of each of the plurality of battery cell assemblies overlaps the middle beam.

3. The battery pack according to claim 1, wherein: Each of the plurality of battery cell assemblies includes a lead cover assembly, Wherein, the lead cover assembly comprises: a lead cover frame; and An integrated circuit is mounted on the lead cover frame.

4. The battery pack according to claim 3, wherein: The foamable refractory material is configured to form a foamed layer when a thermal runaway event occurs in the battery pack, and the foamed layer is a heat-insulating carbonized layer.

5. The battery pack according to claim 4, wherein: The foamed layer is porous.

6. The battery pack according to claim 4, wherein: The foaming layer covers the lead cover assembly of each of the plurality of battery cell assemblies.

7. The battery pack according to claim 1, wherein: The fire-resistant layer covers the upper surface of the middle beam.

8. The battery pack according to claim 1, wherein: The fire-resistant layer covers the upper surface and the side surface of the middle beam.

9. A battery pack comprising: A housing having a bottom plate and side walls; A plurality of battery cell assemblies, wherein the plurality of battery cell assemblies are located on the bottom plate; A middle beam, the middle beam being located between the plurality of battery cell assemblies; a cover plate, the cover plate being combined with the side wall; as well as a fire-resistant layer, the fire-resistant layer being coated on the cover plate, Wherein, the refractory layer comprises a foamable refractory material.

10. The battery pack according to claim 9, wherein: The fire-resistant layer overlaps the middle beam.

11. The battery pack according to claim 9, wherein: The foamable refractory material is configured to form a foamed layer when a thermal runaway event occurs in the battery pack, and the foamed layer is a heat-insulating carbonized layer.

12. The battery pack according to claim 11, wherein: Each of the plurality of battery cell assemblies includes a lead cover assembly, and Wherein, the lead cover assembly comprises: a lead cover frame; and An integrated circuit is mounted on the lead cover frame.

13. The battery pack according to claim 12, wherein: The foaming layer covers the lead cover assembly of each of the plurality of battery cell assemblies.

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