Battery pack and energy storage cabinet

Abstract

The utility model provides a battery pack and an energy storage cabinet. The battery pack comprises a shell and a plurality of battery cells accommodated in the shell; the shell comprises an upper cover and a lower box body, the upper cover covers the lower box body, and the upper cover and the lower box body jointly form a space for accommodating a plurality of battery cells; the lower box body comprises an enclosure frame, a liquid cooling plate and a fastener, the enclosure frame is formed by bending a sheet metal part, the enclosure frame comprises a top wall and a first bottom wall which are opposite in the height direction of the battery pack, the upper cover is arranged on the top wall, the edge of the liquid cooling plate is arranged on the first bottom wall, and the fastener is used for fixing the liquid cooling plate to the enclosure frame. According to the application, the reinforcing beam, the liquid cooling plate and the enclosure frame are fixed by adopting a mode that the contact surface is firstly glued and then the fastener is locked, so that the stress of the fixed point is dispersed, and the risk of structural failure of the fastener locking point caused by stress concentration is reduced. The adhesive tape is pasted in the lower box body (on the liquid cooling plate), so that the minimum gluing thickness between the battery cell and the bottom liquid cooling plate can be ensured even if flatness tolerance exists after the lower box body is glued and assembled with the module.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage, and in particular to a battery pack and an energy storage cabinet. Background Art

[0002] As the volume of battery packs becomes larger and the energy density becomes higher, the requirements for the strength of the shell that accommodates the battery module are getting higher and higher. The shell includes an upper cover and a lower box body, and the high strength of the lower box body basically determines the high strength of the shell.

[0003] In some related technologies, the lower box includes an outer frame made of aluminum profiles and a bottom wall made of a liquid cooling plate, and the outer frame and the bottom wall are welded. Since the liquid cooling plate needs to be welded to the outer frame, etc., the liquid cooling plate needs to be made of aluminum-based materials, resulting in high costs and insufficient connection strength by welding. Utility Model Content

[0004] An embodiment of the present application provides a battery pack and an energy storage cabinet. The lower box of the battery pack in this embodiment can achieve high strength.

[0005] In a first aspect, an embodiment of the present application provides a battery pack, wherein the shell includes an upper cover, a lower box body, and a first fastener for fixing the upper cover and the lower box body, the upper cover covers the lower box body, and the upper cover and the lower box body together form a space for accommodating multiple battery cells; the lower box body includes a frame, a liquid cooling plate, and a second fastener for fixing the liquid cooling plate to the frame, the liquid cooling plate and the upper cover are located on opposite sides of the frame in the height direction of the battery pack, and multiple battery cells are arranged on the liquid cooling plate with a gap between them and the upper cover; the frame includes two long frames opposite to each other in the width direction of the battery pack and two short frames opposite to each other in the length direction of the battery pack, the two long frames both include outer and inner side walls opposite to each other in the width direction of the battery pack and a first bottom wall and a top wall opposite to each other in the height direction of the battery pack, and the top wall, first bottom wall, outer and inner side walls of each long frame are all formed by bending the same sheet metal; the edge of the upper cover is fixed to the top wall by the first fastener, and the edge of the liquid cooling plate is fixed to the first bottom wall by the second fastener.

[0006] In this embodiment, since the long frame in this embodiment is formed by bending sheet metal, it can be bent into a desired shape to enhance strength as needed. High-strength sheet metal can also be used to bend the long frame. Furthermore, the bending of the sheet metal effectively improves the strength of the frame. Furthermore, since the upper cover is located on the top wall and the liquid cooling plate is located on the first bottom wall, the liquid cooling plate and the upper cover are located at different positions on the frame. This allows stress to be concentrated on the frame when securing the edge of the liquid cooling plate and the upper cover. The frame, being strong and less susceptible to damage, effectively ensures the stability of the connection between the frame and the liquid cooling plate, and between the frame and the upper cover. Furthermore, since the safety regulations for the liquid cooling plate and the upper cover are different, the liquid cooling plate and the upper cover can be secured to the first bottom wall and the top wall, respectively, independently from the frame. This allows the liquid cooling plate and the upper cover to be secured to the frame independently according to their respective safety regulations, effectively improving the stability of the connection between the liquid cooling plate and the frame, and between the upper cover and the frame. In addition, the liquid cooling plate is fixed to the frame by fasteners. Compared with fixing the liquid cooling plate to the frame by welding, the connection strength between the frame and the liquid cooling plate can be improved, thereby improving the overall strength of the lower box.

[0007] In some embodiments, the outer wall is larger than the inner wall in the height direction of the battery pack, and the inner wall is located between the first bottom wall and the top wall. In the height direction of the battery pack, one end of the outer wall is located on the top wall, and the other end of the outer wall protrudes from the first bottom wall. The height of the other end of the outer wall protrudes from the first bottom wall is greater than the thickness of the liquid cooling plate. In this embodiment, because the outer wall of the frame extends beyond the liquid cooling plate located on the first bottom wall, the liquid cooling plate is surrounded by the portion of the outer wall that extends beyond the first bottom wall. This effectively reduces the chance of the liquid cooling plate being bumped, effectively preventing the fasteners from being frequently subjected to radial shear forces, thereby reducing the chance of damage to the fasteners and improving the stability of the fastener connection between the liquid cooling plate and the frame.

[0008] In some embodiments, the long side frame further includes an intermediate side wall parallel to the outer side wall and a second bottom wall parallel to the first bottom wall. The outer side wall is positioned between the second bottom wall and the top wall, and the intermediate side wall is positioned between the first and second bottom walls. The height of the intermediate side wall is greater than the thickness of the liquid cooling plate. The top wall, first bottom wall, outer side wall, inner side wall, intermediate side wall, and second bottom wall of the long side frame are formed by bending a single sheet metal member. In this embodiment, because the height of the intermediate side wall is greater than the thickness of the liquid cooling plate, the intermediate side walls of the long and short side frames can surround the liquid cooling plate, effectively protecting the liquid cooling plate from bumps and scratches.

[0009] In some embodiments, each long side frame includes a bend start edge and a bend end edge, which are welded together. The bend start edge is the side of the top wall facing the middle side wall, and the bend end edge is the side of the middle side wall facing the top wall. In this embodiment, since the weld of the long side frame is located at the junction of the middle side wall and the second bottom wall, and the middle side wall and the second bottom wall do not need to be directly fixed to the liquid cooling plate or the upper cover, problems such as weld cracking can be effectively avoided, thereby effectively improving the overall strength of the long side frame.

[0010] In some embodiments, a sealant layer is provided between the edge of the liquid cooling plate and the first bottom wall, and fasteners pass through the edge of the liquid cooling plate, the sealant layer, and the first bottom wall to secure the fasteners to the surrounding frame. In this embodiment, by passing the fasteners through the edge of the liquid cooling plate, the sealant layer, and the first bottom wall to secure the fasteners to the surrounding frame, the sealant layer can disperse stress at the locations where the fasteners or the liquid cooling plate are secured by the fasteners, thereby preventing stress concentration and material failure of the fasteners or the liquid cooling plate. The sealant layer also provides a sealing function.

[0011] In some embodiments, the fastener is a hot-drill screw, which passes through the liquid cooling plate, the sealant layer and the first bottom wall to be fixed to the surrounding frame. In this embodiment, based on the fixing method of the hot-drill screw, the liquid cooling plate, the sealant layer and the surrounding frame are squeezed by the hot-drill screw to form a cylindrical through hole, and the hot-drill screw tip pierces and screws into the liquid cooling plate, the sealant layer and the surrounding frame to be connected, so that drilling, tapping and tightening are completed in one step, and finally a fully meshed threaded connection process is formed between the liquid cooling plate, the sealant layer and the surrounding frame with the hot-drill screw. As a result, the hot-drill screw and the liquid cooling plate, the sealant layer and the surrounding frame can maintain high airtightness, and due to the high degree of meshing of the hot-drill screw with the sealant layer, the stress of the hot-drill screw and the position where the liquid cooling plate is fixed by the hot-drill screw can be effectively dispersed through the sealant layer, so as to improve the connection stability between the liquid cooling plate and the surrounding frame.

[0012] In some embodiments, the top wall, the first bottom wall, the outer side wall, and the inner side wall collectively enclose a receiving cavity, and the hot-drill screw passes through the liquid cooling plate, the sealant layer, and the first bottom wall to enter the receiving cavity. In this embodiment, since the hot-drill screw passes through the liquid cooling plate, the sealant layer, and the lower wall to enter the receiving cavity, a small amount of debris generated during the hot-drill screw fixing process will enter the receiving cavity. The receiving cavity is an inner cavity of the enclosing frame and is generally isolated from the inner cavity of the shell. Therefore, even if debris is generated by the hot-drill screw, it will not enter the inner cavity of the shell, thereby effectively improving the safety of the battery pack.

[0013] In some embodiments, the lower case further includes multiple reinforcing beams, each extending along the width of the battery pack to the two long side frames. Fasteners pass through the reinforcing beams, the liquid cooling plate, the sealant layer, and the first bottom wall to secure the case to the frame. In this embodiment, the reinforcing beams enhance the pressure-bearing capacity of the liquid cooling plate, allowing for greater capacity of battery cells within the case.

[0014] In some embodiments, the lower case further comprises a thermally conductive adhesive and a stopper disposed on the liquid cooling plate. The thermally conductive adhesive is located between the bottom surface of the plurality of battery cells and the liquid cooling plate. The stopper is located between the bottom surface of the plurality of battery cells and the liquid cooling plate. In the height direction of the battery pack, the thickness of the stopper is less than or equal to the thickness of the thermally conductive adhesive. In this embodiment, by providing the stopper between the liquid cooling plate and the plurality of battery cells of the battery module, the stopper can limit the minimum distance between the plurality of battery cells of the battery module and the liquid cooling plate, thereby preventing the distance between the plurality of battery cells and the liquid cooling plate from being too small at some locations. It can also prevent the thickness of the thermally conductive adhesive at certain locations between the plurality of battery cells and the liquid cooling plate from being too thin, thereby effectively improving the uniformity of the thermally conductive adhesive between the plurality of battery cells and the liquid cooling plate, thereby improving the temperature consistency of the plurality of battery cells, thereby improving the service life of the battery pack, and effectively improving the safety of the battery pack. In addition, since the uniformity of the thickness of the thermally conductive adhesive at each location is effectively improved, the stress between the liquid cooling plate and the plurality of battery cells can be released through the thermally conductive adhesive, thereby effectively improving the pressure bearing capacity of the liquid cooling plate.

[0015] In some embodiments, the retaining member comprises a plurality of rubber strips extending along the length of the battery pack. The plurality of rubber strips are spaced apart and disposed on the thermally conductive adhesive. The plurality of battery cells are arranged along the length of the battery pack, and the ends of the plurality of rubber strips protrude from the ends of the plurality of battery cells along the length of the battery pack. In the width direction of the battery pack, the plurality of rubber strips are located between the two sides of the bottom surface of the plurality of battery cells in the width direction of the battery pack. In this embodiment, since the rubber strips are located between the two sides of the bottom surface of the plurality of battery cells in the width direction of the battery pack, that is, in the length direction of the battery cells, the rubber strips are located between the two sides of the bottom surface of the plurality of battery cells. This ensures the retaining function of the rubber strips while also preventing the rubber strips from being located outside the bottom surface of the battery cells in the length direction. Thermally conductive adhesive is applied to the portion of the battery cells outside the length direction. The thermally conductive adhesive allows electrolyte ejected from the battery cells to penetrate between the bottom surface of the battery cells and the liquid cooling plate to prevent thermal runaway, thereby preventing the electrolyte from melting the rubber strips and rendering them ineffective. This can effectively reduce the probability of short circuit between the battery cells and the liquid cooling plate after the battery pack experiences thermal runaway.

[0016] In some embodiments, the lower box further includes an inner insulation layer, an outer insulation layer, and a compression strip. The inner insulation layer is adhered to the side of the liquid cooling plate facing away from the inner cavity of the shell, the outer insulation layer covers the inner insulation layer, and the edge of the outer insulation layer is fixed to the edge of the liquid cooling plate by a compression strip. In this embodiment, the inner insulation layer is first covered on the liquid cooling plate, and the inner insulation layer can usually be glued to the surface of the liquid cooling plate facing away from the inner cavity of the shell by means of glue to reduce the gap between the liquid cooling plate and the inner insulation layer, thereby effectively improving the insulation effect of the inner insulation layer on the liquid cooling plate. The outer insulation layer covers the inner insulation layer, and the insulation effect can be further improved by the outer insulation layer. Moreover, since the edge of the outer insulation layer is fixed to the edge of the liquid cooling plate by a compression strip, the outer insulation layer can not only play a role in heat preservation, but also fix the inner insulation layer. As a result, the inner insulation layer may warp or even fall off over time, affecting its thermal insulation performance. The outer insulation layer can restrain the inner insulation layer. Even if the adhesive between the inner insulation layer and the liquid cold plate loses its viscosity due to aging, the outer insulation layer can still mechanically secure the inner and outer insulation layers to the liquid cold plate. This ensures that the liquid cold plate's thermal insulation capacity does not decrease with component aging throughout the battery pack's lifecycle. Furthermore, it effectively reduces the chance of condensation on the liquid cold plate throughout the battery pack's lifecycle.

[0017] In some embodiments, when the liquid cooling plate is secured to the first bottom wall, both ends of the surrounding frame in the height direction of the battery pack extend beyond the liquid cooling plate. The surrounding frame and the liquid cooling plate form an upper receiving groove and a lower receiving groove arranged in the height direction of the battery pack. Multiple battery cells are disposed in the upper receiving groove, and the inner and outer insulation layers are disposed in the lower receiving groove. That is, in the height direction of the battery pack, the inner and outer insulation layers are located between the first and second bottom walls. In this embodiment, by disposing the multiple battery cells in the upper receiving groove and the inner and outer insulation layers in the lower receiving groove, not only does the battery pack appear neater, but also, by disposing the inner and outer insulation layers in the lower receiving groove, under the protection of the surrounding frame, the chance of the inner and outer insulation layers being scratched is reduced, thereby reducing the chance of the inner and outer insulation layers warping.

[0018] In some embodiments, the outer wall of the enclosure frame is provided with a strip-shaped mounting slot, within which are located multiple lifting structures, each of which is welded to the enclosure frame and each of which is provided with a mounting hole. In this embodiment, since the lifting structures are located within the mounting slots, the mounting slots can be used to position the lifting structures. Combined with the connection between the lifting structures and the enclosure frame, the lifting structures can withstand significant tensile forces. Specifically, the lifting structures are connected to an external lifting mechanism via the mounting holes, for example, by bolts connected to the mounting holes.

[0019] In some embodiments, the battery pack further comprises a rivet nut and a sealing washer. The sealing washer is disposed between the top wall and the upper cover. The rivet nut is secured to the frame, with a portion of the rivet nut protruding from the top wall. In this embodiment, the portion of the rivet nut protruding from the top wall also serves as a positioning mechanism. For example, when the outer edge of the upper cover contacts the rivet nut, the outer edge of the upper cover and the top wall can be precisely squeezed against the sealing washer, preventing either excessive squeezing that would cause the seal to fail or insufficient squeezing that would result in a failure to seal.

[0020] In a second aspect, an embodiment of the present application provides an energy storage cabinet, which includes a cabinet body and one or more battery packs according to any one of the embodiments of the first aspect above, wherein the one or more battery packs are disposed in the cabinet body. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art.

[0022] Figure 1 A schematic structural diagram of a battery pack provided in an embodiment of the present application;

[0023] Figure 2 for Figure 1 Schematic diagram of the exploded structure of the battery pack;

[0024] Figure 3 for Figure 2 A schematic structural diagram of the lower box in the embodiment;

[0025] Figure 4 for Figure 3 A schematic diagram of the exploded structure of the lower box in the embodiment;

[0026] Figure 5 for Figure 4 Schematic diagram of the decomposition structure of the frame in;

[0027] Figure 6 for Figure 2 A schematic diagram of a portion of the structure of the lower box in the embodiment when viewed from above;

[0028] Figure 7 for Figure 2 A top view of the lower box in the embodiment;

[0029] Figure 8 for Figure 7 A partial enlarged schematic diagram of the cross section at AA in the middle;

[0030] Figure 9 for Figure 3 A partial enlarged schematic diagram of point A in the middle;

[0031] Figure 10 for Figure 2 A schematic structural diagram of the lower box body in the embodiment when viewed from above;

[0032] Figure 11 for Figure 10 Schematic diagram of the exploded lower box.

[0033] Description of reference numerals:

[0034] Z, height direction of the battery pack; Y, width direction of the battery pack; X, length direction of the battery pack;

[0035] 1. Battery pack; 2. Housing; 3. Battery module; 4. Battery cell;

[0036] 10. Upper cover; 11. First fastener;

[0037] 20. Lower box;

[0038] 21. Enclosure; 203. Receiving cavity; 204. Mounting slot; 205. Upper receiving slot; 206. Lower receiving slot; 211. Long side frame; 212. Short side frame; 213. Top wall; 214. First bottom wall; 215. Inner side wall; 216. Outer side wall; 217. Reinforcement sheet; 218. Middle side wall; 219. Second bottom wall;

[0039] 22. Liquid cooling plate;

[0040] 231. Sealant layer; 232. Second fastener;

[0041] 24. Lifting structure; 241. Lifting hole;

[0042] 25. Rivet nuts;

[0043] 26. Strengthening beams;

[0044] 27. Thermal conductive adhesive;

[0045] 28. Limiting piece; 281. Rubber strip;

[0046] 291, inner insulation layer; 292, outer insulation layer; 293, compression strip;

[0047] 30. Sealing gasket;

[0048] 311. First insulating layer; 312. Second insulating layer; 313. Insulating tape. DETAILED DESCRIPTION

[0049] The following first explains some of the terms involved in the embodiments of this application.

[0050] The terms "first", "second", "third", "fourth", etc. in the description and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0051] In this specification, the terms "perpendicular" and "parallel" are explained.

[0052] Vertical: The vertical defined in this application is not limited to an absolute vertical intersection relationship (angle of 90 degrees). It allows for non-absolute vertical intersection relationships caused by factors such as assembly tolerance, design tolerance, and structural flatness. It allows for errors in a small angle range. For example, the assembly error range of 80 to 100 degrees can be understood as a vertical relationship.

[0053] Parallel: The parallel defined in this application is not limited to absolute parallelism. This definition of parallelism can be understood as basic parallelism, allowing for situations where the absolute parallelism is not caused by factors such as assembly tolerance, design tolerance, and the influence of structural flatness. These situations will lead to the sliding fitting part and the first door panel not being absolutely parallel, but this application also defines this situation as parallel.

[0054] To facilitate understanding of the energy storage cabinet provided in the embodiments of the present application, the following first introduces its application scenarios. An energy storage cabinet is a system that can store electrical energy in a certain medium and release the stored energy to generate electricity when needed. It can be used as a load balancing device and backup power source in scenarios such as industrial and commercial parks, domestic living environments, large ground power stations, or photovoltaic storage systems. The application of energy storage cabinets is briefly explained using the photovoltaic storage system scenario as an example. A photovoltaic storage system typically includes photovoltaic modules, energy storage converters, energy storage cabinets, and grid-connected inverters. The photovoltaic modules can convert solar energy into direct current (DC) electricity and output it to the grid-connected inverter. The grid-connected inverter can convert DC electricity into alternating current (AC) electricity and transmit this AC energy to the grid, thereby connecting the photovoltaic storage system to the grid. The energy storage cabinet can store a portion of the energy output by the photovoltaic inverter when the energy generated by the photovoltaic modules exceeds the grid's demand for electricity. When the energy output by the photovoltaic modules cannot meet the grid's demand for electricity, the stored energy can be output to the grid, providing a more stable DC source for the grid. The energy storage converter can convert the grid voltage into the supply voltage of the energy storage cabinet, or convert the voltage stored in the energy storage cabinet into the grid voltage and output it to the grid.

[0055] In addition, according to the different power consumption requirements of the application scenarios of energy storage cabinets, energy storage cabinets can also be divided into cabinet-level energy storage cabinets and container-level energy storage cabinets.

[0056] For example, in some embodiments, the energy storage cabinet includes a cabinet body and a battery cluster disposed in the cabinet body.

[0057] The battery cluster includes a plurality of stacked battery packs.

[0058] The energy storage cabinet may further include a cluster control box and a power converter, which are arranged in the cabinet.

[0059] In some embodiments, the power converter includes a PCS (power conversion system) converter, and the cluster control box is connected between the PCS converter and the battery cluster. This design allows the PCS converter to convert the battery cluster's DC power into AC power to power external loads. Furthermore, if the current between the battery cluster and the PCS converter becomes excessive, the cluster control box can promptly disconnect the PCS converter from the battery cluster to prevent accidents such as fire in the battery cluster or external loads.

[0060] In some embodiments, when the battery cluster output voltage falls below the rated voltage, to ensure the stability of the energy storage cabinet's output voltage, the power converter further includes a DC / DC (direct current / direct current) converter. The DCDC converter is connected between the PCS converter and the cluster control box, which is in turn connected between the DCDC converter and the battery cluster. The DCDC converter steps up or down the battery cluster output voltage, thereby ensuring a stable voltage delivered to the PCS converter and, consequently, the stability of the energy storage cabinet's output voltage. Furthermore, if the current between the battery cluster and the PCS converter is excessive, the cluster control box can promptly disconnect the current between the PCS converter and the battery cluster to prevent accidents such as fires in the battery cluster or external loads.

[0061] Figure 1 A schematic structural diagram of a battery pack 1 provided in an embodiment of the present application; Figure 2 for Figure 1 Schematic diagram of the exploded structure of the battery pack 1. Figure 1 The battery pack 1 in the embodiment can be applied not only to energy storage cabinets, but also to the vehicle field or other fields that require the use of the battery pack 1.

[0062] As the volume of the battery pack 1 becomes larger and the energy density becomes higher, the requirements for the strength of the shell 2 that accommodates the battery module 3 become higher and higher. At the same time, the overall lightweight and low cost of the battery pack 1 are also the goals to be pursued. In this application, the overall lightweight and low cost of the battery pack 1 are achieved by achieving the lightweight and low cost of the shell 2 on the premise of meeting the strength of the shell 2.

[0063] Reference Figure 1 and Figure 2 The battery pack 1 includes a housing 2 and a battery module 3 housed in the housing 2. The battery module 3 includes a plurality of arranged battery cells 4. The number of battery modules 3 can be multiple, for example Figure 2 In the embodiment shown, there are four battery modules 3 .

[0064] The housing 2 includes an upper cover 10 and a lower case 20. The upper cover 10 is fixed to the lower case 20 and, together with the lower case 20, forms a housing cavity within which the battery module 3 is housed. Specifically, the battery module 3 is first mounted to the lower case 20 and then secured to the lower case 20 via the upper cover 10, thereby encapsulating the battery module 3.

[0065] As for the lower box body 20, the lower box body 20 is mainly used to carry the battery module 3, so the strength requirement for the lower box body 20 is relatively high. At the same time, under the premise of high strength requirements for the box body, it is also necessary to pursue low cost and stability of use of the lower box body 20.

[0066] In some embodiments, the lower box 20 includes an outer frame formed of an aluminum profile and a bottom wall formed of a liquid cooling plate 22. Since the aluminum profile is not hard enough, it is not easy to fix it to the liquid cooling plate 22 using fasteners such as screws, so the outer frame and the bottom wall are welded. Since the liquid cooling plate 22 needs to be welded to the outer frame, the liquid cooling plate 22 needs to be made of aluminum-based materials, resulting in high costs. Moreover, the outer frame and the liquid cooling plate 22 are connected by welding, and the connection strength is insufficient, and cannot withstand the heavier battery module 3.

[0067] In other embodiments, the lower case 20 is entirely formed from bent sheet metal. Specifically, the outer frame and bottom wall of the lower case 20 are formed by bending sheet metal together, and the liquid cooling plate 22 is then glued to the bottom wall of the lower case 20 via a thermally conductive adhesive. In this embodiment, due to the integrated design of the outer frame and bottom wall, the outer frame's shape is limited by the bottom wall, resulting in insufficient strength and inability to bear significant weight.

[0068] In some further embodiments, the lower case 20 includes an outer frame formed of a profile and a bottom wall formed of a liquid cooling plate 22. The liquid cooling plate 22 is positioned between the outer frame and the upper cover 10. Bolts pass through the outer edge of the upper cover 10 and the liquid cooling plate 22 and are secured to the outer frame. A sealing gasket 30 is provided between the liquid cooling plate 22 and the outer edge of the upper cover 10 to ensure a seal between the liquid cooling plate 22 and the upper cover 10. In this embodiment, since the liquid cooling plate 22, the upper cover 10, and the outer frame are directly secured together by bolts, the bolts are required to withstand the force of tightening the upper cover 10 and the liquid cooling plate 22. Furthermore, the bolts are required to withstand the weight of the battery module 3 when placed on the liquid cooling plate 22. Consequently, the bolts are subject to significant stress. This can easily lead to failure of the connection between the bolts and the outer frame during transportation or when the battery pack 1 is subjected to knocks or vibrations. This can deteriorate the stability of the bolt connections between the upper cover 10, the liquid cooling plate 22, and the outer frame, and also lead to failure of the seal between the upper cover 10 and the liquid cooling plate 22.

[0069] In order to solve the above problems, refer to Figure 3 and Figure 4 The present application provides a lower box body 20 with low cost, high strength and good stability, wherein: Figure 3 for Figure 2 A schematic structural diagram of the lower box body 20 in the embodiment; Figure 4 for Figure 3 A schematic diagram of the exploded structure of the lower box 20 in the embodiment; Figure 5 for Figure 4 Schematic diagram of the exploded structure of the frame 21 in FIG.

[0070] Reference Figure 2-Figure 5 In some embodiments, the lower box 20 includes a surrounding frame 21 , a liquid cooling plate 22 , a sealing layer 231 and a second fastener 232 .

[0071] In order to effectively improve the strength of the frame 21, in this embodiment, the frame 21 and the liquid cooling plate 22 can be independently processed separately and then connected together by assembly, so that the frame 21 serves as the outer frame of the lower case 20, and the liquid cooling plate 22 serves as the bottom wall of the lower case 20. That is, the multiple battery cells 4 are arranged on the liquid cooling plate 22, and there is a gap between the liquid cooling plate 22 and the upper cover 10. That is, the multiple battery cells 4 are supported by the liquid cooling plate 22, and the upper cover 10 does not need to support the multiple battery cells 4. In this embodiment, since the frame 21 is independently designed, the shape design and material design of the frame 21 are no longer restricted, making it easier to manufacture the frame 21 into a shape that can effectively improve its strength. It is also convenient to use higher-strength materials to manufacture the frame 21. Therefore, by independently processing the frame 21, the strength of the frame 21 can be effectively improved.

[0072] It is understood that the frame 21 is an annular hollow structure, that is, an annular frame structure, which is a structure similar to a profile. That is, the frame 21 surrounds a hollow area. For example, in some embodiments, the frame 21 is a rectangular annular hollow structure.

[0073] For example, in some embodiments, the frame 21 includes two long frames 211 opposite to each other in the width direction Y of the battery pack 1 and two short frames 212 opposite to each other in the length direction X of the battery pack 1. The two long frames 211 and the two short frames 212 are connected to form the frame 21 in this embodiment, and the two long frames 211 and the two short frames 212 enclose a hollow area. The long frames 211 and the short frames 212 can be connected together by welding, thereby connecting the two long frames 211 and the two short frames 212 into a whole. In order to improve the connection strength between the long frames 211 and the short frames 212, L-shaped reinforcement sheets 217 can be connected to the long frames 211 and the short frames 212 respectively to improve the connection strength between the long frames 211 and the short frames 212.

[0074] Reference Figure 5 In some embodiments, the two long sides 211 are formed by bending sheet metal. The two short sides 212 are formed by bending sheet metal. Since the frame 21 in this embodiment can be formed by bending sheet metal, it can be bent into a desired shape that can enhance strength according to needs. It is also possible to use sheet metal made of high-strength material to bend the long side 211 or the short side 212. Furthermore, the strength of the frame 21 can be effectively improved by bending the sheet metal. In this embodiment, the high strength of the frame 21 is reasonably utilized to improve the connection stability between the upper cover 10 and the lower box body 20.

[0075] Reference Figure 5In some embodiments, both long frames 211 include an outer wall 216 and an inner wall 215 that are opposed to each other in the width direction Y of the battery pack 1, and a first bottom wall 214 and a top wall 213 that are opposed to each other in the height direction Z of the battery pack 1. The top wall 213, first bottom wall 214, outer wall 216, and inner wall 215 of each long frame 211 are all formed by bending the same sheet metal. In this embodiment, since the top wall 213, first bottom wall 214, outer wall 216, and inner wall 215 of the long frame 211 are all formed by bending the same sheet metal, the connection strength between the top wall 213, first bottom wall 214, outer wall 216, and inner wall 215 can be improved, thereby improving the overall strength of the long frame 211.

[0076] It is understood that the outer wall 216 is located outside the inner wall 215, that is, the inner wall 215 is close to the shell 2 (such as Figure 1 ) inner cavity, and the outer wall 216 of the frame is away from the inner cavity of the shell 2. The top wall 213 and the first bottom wall 214 are located between the inner wall 215 and the outer wall 216, that is, the top wall 213 and the first bottom wall 214 are connected between the inner wall 215 and the outer wall 216, and then the top wall 213, the first bottom wall 214 and the side walls together enclose the receiving cavity 203, and the receiving cavity 203 is connected to the shell 2 (such as Figure 1 )The inner cavity is sealed and isolated.

[0077] Reference Figure 5 In some embodiments, each long frame 211 includes a bend start edge and a bend end edge, and the bend start edge and the bend end edge are welded together. By welding the bend start edge and the bend end edge together, the overall strength of the long frame 211 can be improved and deformation is not easy to occur.

[0078] It is understandable that the two short frames 212 also include a first bottom wall 214, a top wall 213, an outer side wall 216, and an inner side wall 215. The first bottom wall 214 and top wall 213 of the short frames 212 are also opposite each other in the height direction Z of the battery pack 1, and the outer side wall 216 and inner side wall 215 of the short frames 212 are arranged opposite each other in the length direction X of the battery pack 1. The first bottom wall 214, top wall 213, outer side wall 216, and inner side wall 215 of the short frames 212 are also formed by bending the same sheet metal.

[0079] Reference Figure 1-Figure 5 In some embodiments, the edge of the upper cover 10 is fixed to the top wall 213 by the first fastener 11, that is, the edge of the long side of the upper cover 10 is fixedly connected to the top wall 213, and the edge of the liquid cooling plate 22 is fixed to the first bottom wall 214 by the second fastener 232, that is, the edge of the long side of the liquid cooling plate 22 is fixed to the first bottom wall 214.

[0080] It can be understood that in order to improve the fixing strength of the frame 21 and the upper cover 10 and the liquid cooling plate 22, the edge of the short side of the upper cover 10 can also be fixed to the top wall 213 of the short frame 212, and the edge of the short side of the liquid cooling plate 22 can also be fixed to the first bottom wall 214 of the short frame 212.

[0081] In the related art, since the liquid cooling plate 22 and the upper cover 10 are fixed to the surrounding frame 21 by the same second fastener 232, the strength of the liquid cooling plate 22 is not as high as that of the surrounding frame 21, and the liquid cooling plate 22 is located between the upper cover 10 and the surrounding frame 21, the liquid cooling plate 22 needs to withstand greater stress. Under the action of greater stress, the liquid cooling plate 22 is prone to deformation, resulting in loose fixation between the liquid cooling plate 22, the upper cover 10 and the surrounding frame 21, and insufficient connection stability. Compared with the related art, the upper cover 10 and the top wall 213 in this embodiment are fixed by the first fastener 11, and the liquid cooling plate 22 and the first bottom wall 214 are fixed by the second fastener 232, so that the liquid cooling plate 22 and the upper cover 10 are respectively arranged at different positions of the frame 21, that is, the liquid cooling plate 22 and the upper cover 10 are located on opposite sides of the frame 21 in the height direction Z of the battery pack 1, so that when the edge of the liquid cooling plate 22 and the upper cover 10 are fixed, the stress can be more concentrated on the frame 21, and the frame 21 has high strength and is not easily damaged, thereby effectively ensuring the connection stability between the frame 21 and the liquid cooling plate 22 and the frame 21 and the upper cover 10.

[0082] In addition, since the safety regulations of the liquid cooling plate 22 and the upper cover 10 are different, the liquid cooling plate 22 and the upper cover 10 are respectively fixed to the first bottom wall 214 and the top wall 213, and the liquid cooling plate 22 and the upper cover 10 are independently fixed to the frame 21. The liquid cooling plate 22 and the upper cover 10 can be independently fixed to the frame 21 according to the safety requirements of the liquid cooling plate 22 and the upper cover 10, thereby effectively improving the connection stability between the liquid cooling plate 22 and the frame 21 and the connection stability between the upper cover 10 and the frame 21.

[0083] Furthermore, in this embodiment, the liquid cooling plate 22 is secured to the surrounding frame 21 via second fasteners 232. For example, in some embodiments, the second fasteners 232 include screws, which secure the liquid cooling plate 22 to the surrounding frame 21. Compared to welding the liquid cooling plate 22 to the surrounding frame 21, the lower housing 20 is susceptible to stress deformation after welding due to the longer weld seam. Furthermore, the welding process is prone to generating welding slag and weld defects that can cause sealing failure. In this embodiment, securing the liquid cooling plate 22 to the surrounding frame 21 via second fasteners 232 can improve the connection strength between the surrounding frame 21 and the liquid cooling plate 22, as well as the overall strength of the lower housing 20.

[0084] Reference Figure 3-Figure 5To alleviate stress concentration in the second fastener 232, in some embodiments, a sealant layer 231 is provided between the edge of the liquid cooling plate 22 and the first bottom wall 214. Specifically, the sealant layer 231 is provided between the surface of the edge of the liquid cooling plate 22 facing the surrounding frame 21 and the first bottom wall 214 of the surrounding frame 21. The second fastener 232 passes through the edge of the liquid cooling plate 22, the sealant layer 231, and the first bottom wall 214, securing it to the surrounding frame 21. This sealant layer 231 can disperse stress at the location where the second fastener 232 or the liquid cooling plate 22 is secured by the second fastener 232, thereby preventing damage to the second fastener 232 or the liquid cooling plate 22 due to material failure caused by stress concentration. It should be understood that the sealant layer 231 herein not only provides a seal but also acts as a buffer, possessing a certain strength to absorb stress. For example, the sealant layer 231 can be made of rubber, resin, polyvinyl chloride resin, polyurethane, butyl rubber, styrene-butadiene rubber, polyurethane, polyvinyl chloride resin, or other materials.

[0085] Figure 6 for Figure 2 A schematic diagram of a portion of the structure of the lower box 20 in the embodiment when viewed from above. Figure 7 for Figure 2 A top view of the lower box 20 in the embodiment; Figure 8 for Figure 7 A partial enlarged schematic diagram of the cross section at AA in the middle;

[0086] Reference Figure 6-Figure 8 To further alleviate the stress concentration problem at the fixing position of the second fastener 232, in some embodiments, the second fastener 232 comprises a hot-drill screw, which sequentially passes through the liquid cooling plate 22, the sealant layer 231, and the surrounding frame 21. Based on the hot-drill screw fixing method, the liquid cooling plate 22, the sealant layer 231, and the surrounding frame 21 are squeezed by the hot-drill screw to form a cylindrical through-hole. The hot-drill screw tip pierces the hole and screws into the liquid cooling plate 22, the sealant layer 231, and the surrounding frame 21 to be connected. This completes the drilling, tapping, and tightening steps in one process, ultimately forming a fully engaged threaded connection between the liquid cooling plate 22, the sealant layer 231, the surrounding frame 21, and the hot-drill screw. Therefore, the heat flow drill screw and the liquid cooling plate 22, the sealant layer 231 and the surrounding frame 21 can maintain high airtightness, and due to the high degree of engagement between the sealant layer 231 and the heat flow drill screw, the sealant layer 231 can effectively disperse the stress of the heat flow drill screw and the position of the liquid cooling plate 22 fixed by the heat flow drill screw, thereby improving the connection stability between the liquid cooling plate 22 and the surrounding frame 21.

[0087] It can be understood that the hot flow drill screw, also known as the FSD (Flow Drill Screw) screw, is transmitted to the hot flow drill screw through the high-speed rotation motion of the servo motor, acting on the plate to be connected, generating frictional heat, and causing the material to undergo plastic deformation under the action of huge axial pressure. A cylindrical through hole FLOW 'flow' is formed under the extrusion of the flow drill screw, and the tip of the hot flow drill screw pierces and screws into the plate to be connected, so that drilling, tapping, and tightening are completed at one time on the RSF (Robot Assigned Screwing system for Flow Drill Screw) equipment, and finally a fully engaged threaded connection is formed between the plate and the hot flow drill screw.

[0088] It is understandable that the second fastener 232 may also include other fastening structures besides the hot-drill screw, such as rivets, self-tapping screws, etc.

[0089] To effectively prevent the impact of debris introduced by the hot-drilling screw, the hot-drilling screw passes through the liquid cooling plate 22, the sealant layer 231, and the first bottom wall 214 to enter the receiving cavity 203. Since the hot-drilling screw passes through the liquid cooling plate 22, the sealant layer 231, and the first bottom wall 214 to enter the receiving cavity 203, a small amount of debris generated during the hot-drilling screw fixing process will enter the receiving cavity 203. The receiving cavity 203 is an inner cavity of the frame 21 and is generally isolated from the inner cavity of the shell 2. Therefore, even if debris is generated by the hot-drilling screw, it will not enter the inner cavity of the shell 2, thereby effectively improving the safety of the battery pack 1.

[0090] In order to improve the connection stability of the hot flow drill screw to the liquid cooling plate 22 and the surrounding frame 21, refer to Figure 5 and Figure 6In the height direction Z of the battery pack 1, the outer wall 216 is larger than the inner wall 215. The inner wall 215 is located between the first bottom wall 214 and the top wall 213. In the height direction Z of the battery pack 1, one end of the outer wall 216 is located on the top wall 213, while the other end of the outer wall 216 protrudes from the first bottom wall 214. The height of the other end of the outer wall 216 protruding from the first bottom wall 214 is greater than the thickness of the liquid cooling plate 22. In other words, the end of the outer wall 216 of the frame 21 facing the first bottom wall 214 protrudes from the first bottom wall 214 and extends beyond the liquid cooling plate 22 located on the first bottom wall 214. In other words, the outer wall 216 of the frame 21 is taller than the first bottom wall 214 of the frame 21 and taller than the liquid cooling plate 22 located on the first bottom wall 214. In other words, the liquid cooling plate 22 is located in the central area surrounded by the outer wall 216. In this embodiment, since the outer wall 216 of the frame 21 extends beyond the liquid cooling plate 22 located on the first bottom wall 214, the liquid cooling plate 22 is surrounded by the portion of the outer wall 216 extending beyond the first bottom wall 214, thereby effectively reducing the chance of the liquid cooling plate 22 being bumped, and further effectively preventing the heat flow drill screws from being frequently subjected to radial shear force, thereby reducing the chance of the heat flow drill screws being damaged and improving the connection stability of the heat flow drill screws to the liquid cooling plate 22 and the frame 21.

[0091] Specifically, refer to Figure 5 and Figure 6 The long side frame 211 also includes an intermediate side wall 218 parallel to the outer side wall 216 and a second bottom wall 219 parallel to the first bottom wall 214. The outer side wall 216 is located between the second bottom wall 219 and the top wall 213, and the intermediate side wall 218 is located between the first bottom wall 214 and the second bottom wall 219. The height of the intermediate side wall 218 is greater than the thickness of the liquid cooling plate 22. The top wall 213, first bottom wall 214, outer side wall 216, inner side wall 215, intermediate side wall 218, and second bottom wall 219 of the long side frame 211 are formed by bending the same sheet metal. In this embodiment, the height of the intermediate side wall 218 is greater than the thickness of the liquid cooling plate 22, so that the intermediate side walls 218 of the long side frame 211 and the intermediate side walls 218 of the short side frame 212 can surround the liquid cooling plate 22, effectively protecting the liquid cooling plate 22 from being bumped.

[0092] Reference Figure 5 In some embodiments, the starting edge of the bend is the side of the top wall 213 facing the middle side wall 218, and the ending edge of the bend is the side of the middle side wall 218 facing the top wall 213. In this embodiment, since the weld of the long side frame 211 is located at the junction of the middle side wall 218 and the second bottom wall 219, and the middle side wall 218 and the second bottom wall 219 do not need to be directly fixed to the liquid cooling plate 22 or the upper cover 10, etc., problems such as weld cracking can be effectively avoided, thereby effectively improving the overall strength of the long side frame 211.

[0093] Reference Figure 3 and Figure 4 In some embodiments, the inner sidewall 215 is provided with a first insulating layer 311, and the side of the liquid cooling plate 22 used to support multiple battery cells 4 is provided with a second insulating layer 312. An insulating rubber strip 313 is provided at the junction of the liquid cooling plate 22 and the inner sidewall 215, connecting the first insulating layer 311 and the second insulating layer 312 together via the insulating rubber strip 313. In this embodiment, the inner sidewall 215 is provided with the first insulating layer 311, thereby preventing a short circuit between the metal shell of the battery cell 4 and the inner sidewall 215 even when the distance between the inner sidewall 215 and the sidewall of the metal shell of the battery cell does not meet the safety requirements. The second insulating layer 312 can also insulate and isolate the bottom wall of the shell of the battery cell 4 from the liquid cooling plate 22, thereby preventing a short circuit between the liquid cooling plate and the bottom wall of the shell of the battery cell 4. Furthermore, the insulating rubber strip 313 is provided at the junction of the liquid cooling plate 22 and the inner sidewall 215, connecting the first insulating layer 311 and the second insulating layer 312 together via the insulating rubber strip 313. This insulates the second fasteners 232 securing the liquid cooling plate 22 and the first bottom wall 214 from the battery cells 4, preventing current from flowing from the bottom wall of the battery cell 4's housing to the surface of the liquid cooling plate 22 and toward the second fasteners 232. This prevents short circuits between the metal housing of the battery cell 4 and the second fasteners 232. The first insulating layer 311, the second insulating layer 312, and the insulating rubber strips 313 can comprehensively reduce the probability of short circuits between the battery cell 4 and the lower case 20.

[0094] It is understood that the second insulating layer 312 can cover the entire surface of the liquid cooling plate 22. Of course, in other embodiments, the second insulating layer 312 can also be located between the liquid cooling plate 22 and the edges of the plurality of battery cells 4 in the width direction Y of the battery pack 1. In other words, the second insulating layer 312 is only provided at the edges of the liquid cooling plate 22 to reduce the impact on the thermal conductivity of the battery cells 4.

[0095] Figure 9 for Figure 3 A local enlarged schematic diagram of point A in the middle.

[0096] Reference Figure 3 and Figure 9In some embodiments, the outer surface of the outer sidewall 216 of the enclosure 21 is provided with a strip-shaped mounting groove 204. Multiple lifting structures 24 are disposed within the mounting groove 204. The multiple lifting structures 24 are welded to the enclosure 21, and each of the multiple lifting structures 24 is provided with a lifting hole 241. Because the lifting structures 24 are disposed within the mounting groove 204, the mounting groove 204 can be used to limit the position of the lifting structures 24. Combined with the connection between the lifting structures 24 and the enclosure 21, the lifting structures 24 can withstand significant tensile forces. Specifically, the lifting structures 24 are connected to an external lifting mechanism via the lifting holes 241, such as by bolts connected to the lifting holes 241.

[0097] It is understood that the mounting groove 204 can be formed by bending, for example, by continuously bending the outer side wall 216. The mounting groove 204 can be formed in either the long frame 211 or the short frame 212.

[0098] On the premise that the liquid cooling plate 22 is stably fixed to the frame 21, it is also important to ensure the sealing of the connection between the upper cover 10 and the lower box 20. To ensure the sealing of the connection between the upper cover 10 and the lower box 20, the sealing gasket 30 located between the top wall 213 and the outer edge of the upper cover 10 must be able to effectively perform its sealing function. Figure 9 In some embodiments, the outer edge of the upper cover 10 and the surrounding frame 21 are connected by bolts. Specifically, a rivet nut 25 is fixed to the surrounding frame 21. For example, the rivet nut 25 is fixed to the top wall 213 of the surrounding frame 21, and then the outer edge of the upper cover 10 and the surrounding frame 21 are fixed together by the rivet nut 25 and the bolts.

[0099] Reference Figure 9 To prevent the sealing gasket 30 from failing to seal, in some embodiments, a portion of the rivet nut 25 protrudes from the top wall 213. This portion of the rivet nut 25 protruding from the top wall 213 can act as a limiter. Specifically, the distance between the outer edge of the bolt cover 10 and the top wall 213 can be limited to no less than the height of the portion of the rivet nut 25 protruding from the top wall 213, thereby preventing the sealing gasket 30 from being squeezed excessively and failing to seal. In addition, the portion of the rivet nut 25 protruding from the top wall 213 can also serve as a positioning function. For example, when the outer edge of the upper cover 10 contacts the rivet nut 25, it can ensure that the outer edge of the upper cover 10 and the top wall 213 squeeze the sealing gasket 30 just right, preventing excessive squeezing and sealing failure, and preventing insufficient squeezing and failure to seal.

[0100] Reference Figure 4 and Figure 6In order to improve the pressure bearing capacity of the liquid cooling plate 22, in some embodiments, the lower box 20 further includes a reinforcing beam 26. The reinforcing beam 26 is located on the side of the liquid cooling plate 22 away from the battery module 3, and the reinforcing beam 26 is fixed to the frame 21. Thus, the reinforcing beam 26 can improve the pressure bearing capacity of the liquid cooling plate 22, so that the housing 2 (such as Figure 1 )The inner cavity accommodates more battery cells 4.

[0101] Reference Figure 4-Figure 6 For example, in a specific embodiment, the reinforcement beam 26 can be fixed to the first bottom wall 214 by screws, such as by screws passing through the edge of the reinforcement beam 26, the edge of the liquid cooling plate 22, and the first bottom wall 214 and the surrounding frame 21.

[0102] According to Figure 4 In some embodiments, there are multiple reinforcing beams 26 , which are spaced apart along the lengthwise direction X of the battery pack 1 . The lengthwise directions of the multiple reinforcing beams 26 are aligned with the widthwise direction Y of the battery pack 1 . The ends of the reinforcing beams 26 in the lengthwise direction extend onto the frame 21 , and the edges of the reinforcing beams 26 are then fixed to the frame 21 . The reinforcing beams 26 effectively enhance the pressure-bearing capacity of the liquid cooling plate 22 .

[0103] When the frame 21 is a rectangular ring structure, it includes two long sides 211 that oppose each other in the length direction X of the battery pack 1 and two short sides 212 that oppose each other in the width direction Y of the battery pack 1. The two short sides 212 are located between the two long sides 211. The two long sides 211 and the two short sides 212 are connected to form a rectangular ring structure. The two ends of the multiple reinforcement beams 26 in the length direction extend to the two long frames 21 and are fixed to the two long sides 211. This shortens the length of the reinforcement beams 26, improves the bending strength and pressure bearing capacity of the reinforcement beams 26, and effectively improves the pressure bearing capacity of the liquid cooling plate 22.

[0104] It is understood that in some other embodiments, the reinforcement beam 26 may be extended along its length to the two short frames 212. Alternatively, part of the reinforcement beam 26 may be extended along its length to the two short frames 212, and part of the reinforcement beam 26 may be extended along its length to the two long frames 211.

[0105] For larger battery packs, the liquid cooling plate is typically larger. Due to manufacturing tolerances, the finished liquid cooling plate may have planar variations. Applying thermal adhesive directly to the side of the liquid cooling plate facing the battery module and then placing the battery module on top of the adhesive can lead to random fluctuations in the adhesive pressure between the battery module and the cold plate after the battery module is installed, depending on the planarity tolerances between the two. This can result in excessive adhesive in some locations, insufficient adhesive in others, or even direct contact between the battery module and the cold plate. For these reasons, the uneven thickness of the thermal adhesive in different locations can lead to inconsistent thermal conductivity at different locations within the battery module, reducing temperature consistency and impacting the long-term life of the battery pack. Furthermore, due to the uneven thickness of the thermal adhesive, areas that are too thin or too thick are prone to debonding under vibration, resulting in poor adhesion between the battery module and the adhesive, and ultimately uneven heat dissipation. Furthermore, if the thermal adhesive is too thin, the insulation withstand voltage capability in that location will also decrease, compromising the safety of the battery pack.

[0106] Reference Figure 2 、 Figure 3 and Figure 7 To address the above issues, in some embodiments, the lower housing 20 further includes a thermally conductive adhesive 27 disposed on the liquid cooling plate 22 and a retaining member 28 disposed on the liquid cooling plate 22. Both the thermally conductive adhesive 27 and the retaining member 28 are located on the inner surface of the liquid cooling plate 22, that is, both are disposed on the surface of the liquid cooling plate 22 facing the battery module 3. The thermally conductive adhesive 27 is disposed between the multiple battery cells 4 of the battery module 3 and the inner surface of the liquid cooling plate 22, and is used to bond the multiple battery cells 4 to the liquid cooling plate 22, thereby achieving heat conduction and insulation between the multiple battery cells 4 and the liquid cooling plate 22. By providing the limiting member 28 between the inner surface of the liquid cooling plate 22 and the multiple battery cells 4 of the battery module 3, the limiting member 28 can limit the minimum distance between the multiple battery cells 4 of the battery module 3 and the liquid cooling plate 22, thereby preventing the distance between the multiple battery cells 4 and the liquid cooling plate 22 from being too small at some locations, and also preventing the thickness of the thermal conductive adhesive 27 from being too thin at certain locations between the multiple battery cells 4 and the liquid cooling plate 22. This can effectively improve the uniformity of the thermal conductive adhesive 27 between the multiple battery cells 4 and the liquid cooling plate 22, thereby improving the temperature consistency of the multiple battery cells 4, thereby increasing the service life of the battery pack 1 and effectively improving the safety of the battery pack 1. In addition, since the uniformity of the thickness of the thermal conductive adhesive 27 at each location is effectively improved, the stress between the liquid cooling plate 22 and the multiple battery cells 4 can be released through the thermal conductive adhesive 27, thereby effectively improving the pressure bearing capacity of the liquid cooling plate 22.

[0107] Reference Figure 2 、 Figure 3 and Figure 7In some embodiments, the thickness of the retaining member 28 in the height direction Z of the battery pack 1 is less than or equal to the thickness of the thermal adhesive 27. That is, after the multiple battery cells 4 are placed on the liquid cooling plate 22, the minimum thickness of the thermal adhesive 27 after being compressed by the weight of the battery cells 4 is equal to the thickness of the retaining member 28. Of course, there are also cases where the thickness of the thermal adhesive 27 is still greater than the thickness of the retaining member 28 after the thermal adhesive 27 is compressed by the multiple battery cells 4.

[0108] The limiting member 28 in this embodiment is usually made of an insulating hard material, which can ensure the insulation between the battery cells 4 and the liquid cooling plate 22 and can also ensure that no obvious deformation occurs after being squeezed by multiple battery cells 4.

[0109] Reference Figure 2 、 Figure 3 and Figure 7 In some embodiments, the retaining member 28 includes a plurality of rubber strips 281 extending along the length direction X of the battery pack 1. The plurality of rubber strips 281 are spaced apart on the thermal adhesive 27. The ends of the plurality of rubber strips 281 protrude beyond the ends of the battery module 3 along the length direction X of the battery pack 1. In other words, the ends of the plurality of rubber strips 281 protrude beyond the ends of the plurality of battery cells 4 along the length direction X of the battery pack 1. Thus, the plurality of rubber strips 281 ensure that the plurality of battery cells 4 are stably placed on the plurality of rubber strips 281. This prevents portions of the battery cells 4 from being properly supported by the rubber strips 281 and thus unable to be restrained by the rubber strips 281. This prevents portions of the battery cells 4 from having too little thickness of the thermal adhesive 27 between the liquid cooling plate 22 and the battery cooling plate 22. It will be appreciated that at least two rubber strips 281 are sufficient to stably position the plurality of battery cells 4, ensuring uniformity of the thermal adhesive 27 between the plurality of battery cells 4 and the liquid cooling plate 22.

[0110] It is understandable that the thermally conductive adhesive 27 is usually made of a high-temperature resistant material, that is, in a high-temperature environment, such as when the battery cell 4 thermally runs away and sprays electrolyte, it can still stably ensure its insulation performance. In order to ensure that in the thermal runaway state, the electrolyte sprayed from the battery cell 4 can avoid contact with the limiter 28 and damage or melt the limiter 28. In some embodiments, in the width direction Y of the battery pack 1, the rubber pad 281 is located between the two sides of the bottom surface of the multiple battery cells 4 in the width direction Y of the battery pack 1. That is, in the length direction of the battery cell 4, the rubber pad 281 is located between the two sides of the bottom surface of the multiple battery cells 4. This ensures that the rubber strip 281 functions as a limiter and prevents it from being positioned outside the bottom surface of the battery cell 4 along its length. Thermally conductive adhesive 27 is provided on the portion of the battery cell 4 outside its length. This allows the electrolyte ejected from the battery cell 4 to penetrate between the bottom surface of the battery cell 4 and the liquid cooling plate 22, preventing the electrolyte from melting the rubber strip 281 and rendering it ineffective. This effectively reduces the probability of a short circuit between the battery cell 4 and the liquid cooling plate 22 after the battery cell 4 within the battery pack 1 experiences thermal runaway.

[0111] It is understandable that the rubber strip 281 should be as thin as possible, for example, much smaller than the length of the battery cell 4. For example, in some embodiments, the width of the rubber strip 281 is less than 8 mm.

[0112] It is understandable that in some other embodiments, the gasket strips 281 may be arranged in other ways, such as arranging multiple gasket strips 281 along the width direction Y of the battery pack 1.

[0113] Figure 10 for Figure 2 A schematic structural diagram of the lower box body 20 in the embodiment when viewed from above; Figure 11 for Figure 10 Schematic diagram of the decomposition of the lower box body 20.

[0114] Reference Figure 2 and Figure 10 In order to improve the heat dissipation capacity of the multiple battery cells 4, in some embodiments, the lower box 20 further includes a heat preservation layer, which is provided on the side of the liquid cooling plate 22 away from the housing 2 (such as Figure 1 ) side of the inner cavity, the provision of the thermal insulation layer can reduce the amount of heat absorbed by the liquid cooling plate 22 from the outside, allowing more heat to be exchanged with the heat of the battery cells 4, thereby improving the heat dissipation performance of the liquid cooling plate 22. Furthermore, the provision of the thermal insulation layer can also reduce the probability of condensation on the side of the liquid cooling plate 22 facing away from the inner cavity of the housing 2.

[0115] Reference Figure 2 、 Figure 10 and Figure 11In some embodiments, the lower box 20 further includes an inner insulation layer 291, an outer insulation layer 292, and a compression strip 293. The inner insulation layer 291 is attached to the side of the liquid cooling plate 22 away from the accommodating cavity, and the outer insulation layer 292 covers the inner insulation layer 291. The edge of the outer insulation layer 292 is fixed to the edge of the liquid cooling plate 22 by the compression strip 293. In this embodiment, the inner insulation layer 291 is first covered on the liquid cooling plate 22, and the inner insulation layer 291 can usually be glued to the side of the liquid cooling plate 22 away from the shell 2 (such as Figure 1 ) on the surface of the inner cavity to reduce the gap between the liquid cooling plate 22 and the inner insulation layer 291, thereby effectively improving the thermal insulation effect of the inner insulation layer 291 on the liquid cooling plate 22. The outer insulation layer 292 covers the inner insulation layer 291, further improving the thermal insulation effect. Moreover, because the edge of the outer insulation layer 292 is fixed to the edge of the liquid cooling plate 22 by the compression strip 293, the outer insulation layer 292 not only provides thermal insulation, but also serves to secure the inner insulation layer 291. As a result, if the inner insulation layer 291 warps or even falls off over time, affecting its insulation performance, the outer insulation layer 292 can restrict the inner insulation layer 291. Even if the adhesive between the inner insulation layer 291 and the liquid cooling plate 22 loses its viscosity due to aging, the outer insulation layer 292 can still mechanically secure the inner and outer insulation layers 291 and 292 to the liquid cooling plate 22. This ensures that the insulation performance of the liquid cooling plate 22 does not decrease with component aging throughout the life cycle of the battery pack 1. Furthermore, the likelihood of condensation forming on the liquid cooling plate 22 is effectively reduced throughout the life cycle of the battery pack 1.

[0116] Reference Figure 8 、 Figure 10 and Figure 11 In some embodiments, when the liquid cooling plate 22 is fixed to the first bottom wall 214, both ends of the surrounding frame 21 in the height direction Z of the battery pack 1 extend beyond the liquid cooling plate 22. The surrounding frame 21 and the liquid cooling plate 22 form an upper receiving groove 205 and a lower receiving groove 206 arranged in the height direction Z of the battery pack 1. The multiple battery cells 4 of the battery module 3 are arranged in the upper receiving groove 205, and the inner insulation layer 291 and the outer insulation layer 292 are arranged in the lower receiving groove 206. That is, in the height direction Z of the battery pack 1, the inner insulation layer 291 and the outer insulation layer 292 are located between the first bottom wall 214 and the second bottom wall 219. In this embodiment, by arranging multiple battery cells 4 in the upper receiving groove 205 and arranging the inner insulation layer 291 and the outer insulation layer 292 in the lower receiving groove 206, not only can the battery pack 1 be made neater in appearance, but also, by arranging the inner insulation layer 291 and the outer insulation layer 292 in the lower receiving groove 206, under the protection of the frame 21, the probability of the inner insulation layer 291 and the outer insulation layer 292 being scratched can be reduced, thereby reducing the probability of the inner insulation layer 291 and the outer insulation layer 292 being lifted up.

[0117] Reference Figure 8 、 Figure 10 and Figure 11 In some embodiments, multiple reinforcement beams 26 divide the surface of the liquid cooling plate 22 facing away from the inner cavity of the housing 2 into multiple regions. Each region is covered with an inner insulation layer 291. The height of the inner insulation layer 291 after bonding is substantially the same as the height of the reinforcement beams 26. Then, a single outer insulation layer 292 covers the multiple inner insulation layers 291 and is secured to the liquid cooling plate 22 or the surrounding frame 21 via compression strips 293. This design allows for a coordinated and rational overall design of the battery pack 1.

[0118] In some embodiments, the inner insulation layer 291 and the outer insulation layer 292 may both be insulation foam. Of course, the inner insulation layer 291 and the outer insulation layer 292 may also be other insulation structures, such as silicone rubber, fiberglass, flexible rubber foam, carbon fiber, etc.

[0119] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A battery pack, characterized in that: The battery pack includes a shell and a plurality of battery cells; The housing includes an upper cover, a lower box body, and a first fastener for fixing the upper cover and the lower box body, the upper cover is covered on the lower box body, and the upper cover and the lower box body together form a space for accommodating the multiple battery cells; The lower box includes a surrounding frame, a liquid cooling plate, and a second fastener for fixing the liquid cooling plate to the surrounding frame. The liquid cooling plate and the upper cover are located on opposite sides of the surrounding frame in the height direction of the battery pack. The multiple battery cells are arranged on the liquid cooling plate with a gap between them and the upper cover. The surrounding frame includes two long frames opposite to each other in the width direction of the battery pack and two short frames opposite to each other in the length direction of the battery pack. The two long frames each include an outer wall and an inner wall opposite to each other in the width direction of the battery pack, and a first bottom wall and a top wall opposite to each other in the height direction of the battery pack. The top wall, first bottom wall, outer wall and inner wall of each long frame are formed by bending the same sheet metal part. The edge of the upper cover is fixed to the top wall by the first fastener, and the edge of the liquid cooling plate is fixed to the first bottom wall by the second fastener.

2. The battery pack according to claim 1, wherein: In the height direction of the battery pack, the size of the outer wall is larger than the size of the inner wall, and the inner wall is located between the first bottom wall and the top wall. In the height direction of the battery pack, one end of the outer wall is provided on the top wall, and the other end of the outer wall protrudes from the first bottom wall, and the height by which the other end of the outer wall protrudes from the first bottom wall is greater than the thickness of the liquid cooling plate.

3. The battery pack according to claim 2, wherein: The long frame further includes an intermediate side wall parallel to the outer side wall and a second bottom wall parallel to the first bottom wall, the outer side wall is located between the second bottom wall and the top wall, the intermediate side wall is located between the first bottom wall and the second bottom wall, and the height of the intermediate side wall is greater than the thickness of the liquid cooling plate; The top wall, the first bottom wall, the outer side wall, the inner side wall, the middle side wall and the second bottom wall of the long frame are formed by bending the same sheet metal part.

4. The battery pack according to claim 3, wherein: Each of the long frames includes a bending start edge and a bending end edge, the bending start edge and the bending end edge are welded, the bending start edge is the side of the top wall facing the middle side wall, and the bending end edge is the side of the middle side wall facing the top wall.

5. The battery pack according to any one of claims 1 to 4, characterized in that: The second fastener includes a hot-drill screw. A sealant layer is provided between the edge of the liquid cooling plate and the first bottom wall. The hot-drill screw passes through the edge of the liquid cooling plate, the sealant layer and the first bottom wall and is fixed to the surrounding frame.

6. The battery pack according to claim 5, characterized in that: The top wall, the first bottom wall, the outer wall and the inner wall together form a receiving inner cavity, and the hot flow drill screw passes through the liquid cooling plate, the sealant layer and the first bottom wall to enter the receiving inner cavity.

7. The battery pack according to claim 5, characterized in that: The lower box body also includes a plurality of reinforcing beams, the ends of which extend to the two long frames along the width direction of the battery pack respectively, and the second fastener passes through the reinforcing beams, the liquid cooling plate, the sealant layer and the first bottom wall and is fixed to the frame.

8. The battery pack according to any one of claims 1 to 4, characterized in that: The lower box body also includes a thermally conductive adhesive and a limiter provided on the liquid cooling plate. The thermally conductive adhesive is located between the bottom surface of the multiple battery cells and the liquid cooling plate. The limiter is located between the bottom surface of the multiple battery cells and the liquid cooling plate. In the height direction of the battery pack, the thickness of the limiter is less than or equal to the thickness of the thermally conductive adhesive.

9. The battery pack according to claim 8, characterized in that: The limiting member includes a plurality of rubber pads extending along the length direction of the battery pack, the plurality of rubber pads are arranged on the thermal conductive adhesive at intervals, the plurality of battery cells are arranged along the length direction of the battery pack, and two ends of the plurality of rubber pads protrude from two ends of the plurality of battery cells along the length direction of the battery pack; In the width direction of the battery pack, the plurality of rubber gaskets are located between two sides of the bottom surfaces of the plurality of battery cells in the width direction of the battery pack.

10. The battery pack according to any one of claims 1 to 4, characterized in that: The inner wall is provided with a first insulating layer, and a second insulating layer is provided on a side of the liquid cooling plate for supporting the multiple battery cells. An insulating strip is provided at the junction of the liquid cooling plate and the inner wall, and the first insulating layer and the second insulating layer are connected together by the insulating strip.

11. The battery pack according to claim 3, wherein: The lower box body also includes an inner insulation layer, an outer insulation layer and a compression strip. The inner insulation layer is adhered to the side of the liquid cooling plate away from the inner cavity of the shell, the outer insulation layer covers the inner insulation layer, and the edge of the outer insulation layer is fixed to the edge of the liquid cooling plate through the compression strip.

12. The battery pack according to claim 11, wherein: In the height direction of the battery pack, the inner thermal insulation layer and the outer thermal insulation layer are located between the first bottom wall and the second bottom wall.

13. The battery pack according to any one of claims 1 to 4, characterized in that: The side wall of the surrounding frame is provided with a strip-shaped installation groove, and a plurality of hanging structures are provided in the installation groove. The plurality of hanging structures are welded to the surrounding frame, and the plurality of hanging structures are all provided with hanging holes.

14. The battery pack according to any one of claims 1 to 4, characterized in that: The battery pack further includes a rivet nut and a sealing washer, wherein the sealing washer is arranged between the top wall and the upper cover, the rivet nut is fixed to the surrounding frame, and a portion of the rivet nut protrudes from the top wall.

15. An energy storage cabinet, characterized in that: The energy storage cabinet includes a cabinet body and one or more battery packs according to any one of claims 1 to 14, wherein the one or more battery packs are arranged in the cabinet body.

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