A battery pack and a method of assembling the same

Abstract

The application relates to the technical field of batteries, and discloses a battery pack and an assembling method thereof. The battery pack comprises a shell, the shell comprises a frame, the frame comprises a plurality of side beams, the plurality of side beams are combined to form a containing cavity, each side beam has a first region close to the containing cavity and a second region on the side of the first region away from the containing cavity, at least one side beam is provided with a mounting channel extending along the length direction of the side beam and located in the second region, and a medium bus is arranged in the mounting channel; a plurality of thermal management plates are vertically and spacedly arranged in the containing cavity, two ends of each thermal management plate are respectively connected to the inner walls of two oppositely arranged side beams, and each thermal management plate has a medium flow channel in communication with the medium bus. The application has the advantages of high internal space utilization, excellent heat dissipation performance and good structural integration.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery pack and its assembly method. Background Technology

[0002] Traditional battery packs typically use liquid cooling plates laid flat at the bottom of the cells, resulting in uneven cooling of tall cells and creating a significant temperature gradient along the height, thus affecting the battery's cycle life and power performance. Furthermore, the heat exchange efficiency between the liquid cooling plate and the cell is low due to the limited bottom contact area. To improve cooling uniformity, some existing solutions use multiple vertically arranged liquid cooling plates attached to the cell sidewalls to increase the heat exchange area and improve heat dissipation. However, such structures require complex busbar and shunt piping, which not only increases the difficulty of system integration but also occupies valuable internal space, leading to a decrease in the overall energy density of the battery pack and limiting its compact layout. Summary of the Invention

[0003] In view of the above-mentioned shortcomings of the existing technology, the technical problem to be solved by the present invention is to propose a battery pack with high internal space utilization, excellent heat dissipation performance, good structural integration and easy assembly and maintenance, and the assembly method thereof.

[0004] The technical solution adopted by the present invention to solve its technical problem is to provide a battery pack, comprising:

[0005] The housing includes a frame, the frame includes a plurality of side beams, the plurality of side beams together form a receiving cavity, each side beam has a first region close to the receiving cavity and a second region located on the side of the first region away from the receiving cavity, at least one side beam is provided with an installation channel extending along its own length direction and located in the second region, and the installation channel has a built-in medium manifold.

[0006] Multiple heat management plates are vertically and spaced apart within the accommodating cavity. Each heat management plate has its two ends connected to the inner walls of two oppositely arranged side beams, and each heat management plate has a medium flow channel communicating with the medium manifold.

[0007] In the aforementioned battery pack, the side beam includes two first side beams arranged opposite to each other along a first direction of the housing. Each of the two first side beams is provided with the mounting channel and a plurality of first filling channels. The plurality of first filling channels are located in the second region, and are arranged at intervals along the periphery of the side of the mounting channel away from the first region, and extend along the length direction of the first side beam. The first filling channels are filled with reinforcing adhesive.

[0008] In one of the battery packs described above, the cross-sectional area of ​​the mounting channel is larger than the cross-sectional area of ​​the medium manifold, and the first region is provided with at least one vent hole with both ends communicating with the mounting channel and the accommodating cavity respectively.

[0009] In one of the aforementioned battery packs, a partition is provided within the mounting channel, which divides the mounting channel into an independent upper channel and a lower channel. The medium manifold includes an input manifold located in the upper channel and an output manifold located in the lower channel. The cross-sectional area of ​​the upper channel is larger than that of the input manifold, and the cross-sectional area of ​​the lower channel is larger than that of the output manifold.

[0010] In one of the battery packs described above, the first region of the first side beam is further provided with a plurality of first through holes and second through holes arranged at intervals along the length of the first side beam. The two ends of the plurality of first through holes are respectively connected to the upper channel and the accommodating cavity, and the two ends of the plurality of second through holes are respectively connected to the lower channel and the accommodating cavity.

[0011] In the aforementioned battery pack, each of the thermal management boards has a medium flow channel corresponding to a first through hole and a second through hole. The medium flow channel includes at least one input medium flow channel and an output medium flow channel. The input medium flow channel of each thermal management board is connected to the input manifold through the first through hole via a first connector, and the output medium flow channel is connected to the output manifold through the second through hole via a second connector.

[0012] In one of the battery packs described above, at least one of the first side beams has a mounting groove on the side of the first region facing the receiving cavity. The mounting groove extends along the length of the first side beam and is recessed toward the second region.

[0013] In one of the battery packs described above, the side beam further includes two second side beams arranged opposite to each other along a second direction of the housing. The second side beams are connected to the first side beam. At least one of the second side beams has a medium flow channel communicating with the medium manifold in its first region. The medium flow channel is located in the first region of the second side beam. The second region of the second side beam has a plurality of second filling channels arranged at intervals along the height direction of the housing. The second filling channels are filled with reinforcing adhesive.

[0014] In the aforementioned battery pack, the plurality of thermal management plates include a first thermal management plate and a second thermal management plate of different thicknesses. The first thermal management plate and the second thermal management plate are arranged alternately and at intervals along the second direction of the housing and are connected to two oppositely arranged first side beams. An electrical installation area is formed between the first thermal management plate or the second thermal management plate and at least one second side beam.

[0015] In one of the aforementioned battery packs, a control system module is provided in the electrical installation area. The control system module abuts against the first thermal management board or the second thermal management board and has a copper busbar electrically connected to the battery module and / or a flexible board communicatively connected to the battery module. The copper busbar is attached to the inner wall of the first side beam, and the flexible board is fitted into the mounting groove.

[0016] In the aforementioned battery pack, there is at least one set of battery modules. The battery module includes multiple battery cells and two end plates. The multiple battery cells are stacked in at least two rows and two columns to form a battery cell group. The two end plates are respectively disposed at both ends of the battery cell group. The tabs at both ends of each battery cell have a connecting portion that is bent in the vertical direction. When the multiple battery cells are stacked, the connecting portions of two adjacent battery cells are attached to each other, and at least one welding groove is provided on the end plate that penetrates itself and is opposite to one of the connecting portions.

[0017] In one of the battery packs described above, the battery module further includes a buffer between two adjacent cells arranged along the stacking direction, and at least one end plate is provided with a positive input terminal and a negative input terminal, wherein the positive input terminal and the negative input terminal have elastic bending portions.

[0018] In one of the battery packs described above, the housing further includes a first cover plate and a second cover plate detachably disposed on opposite sides of the frame. The first cover plate and the second cover plate cooperate to close the accommodating cavity. A pressure plate is also provided between the first cover plate and / or the second cover plate and the battery module. The pressure plate is provided with a plurality of positioning grooves that form an interlocking fit with the thermal management plate. A plurality of adapter plates are also provided on the side of the pressure plate away from the battery module. The adapter plates are welded to the protrusions of the thermal management plate that pass through the positioning grooves.

[0019] In one of the battery packs described above, a reinforcing adhesive or heat-insulating component is provided between the pressure plate and the first cover plate and / or the second cover plate. The first cover plate and / or the second cover plate have multiple recessed areas on the side away from the battery module. Each recessed area includes a first cavity and a second cavity with different recessed depths. The bottom surface of the first cavity abuts against the pressure plate, and there is a gap between the bottom surface of the second cavity and the pressure plate.

[0020] The technical solution adopted by the present invention to solve its technical problem is to also provide a battery pack assembly method, including the following steps:

[0021] S1, two first side beams arranged opposite each other along the first direction of the shell and two second side beams arranged opposite each other along the second direction of the shell are joined together to form a frame with an accommodating cavity, and each side beam is fixed by welding to form the main frame of the battery pack;

[0022] S2, multiple first heat management plates and second heat management plates of different thicknesses are arranged alternately within the frame to form multiple cavities within the frame, and the first heat management plates and second heat management plates are arranged alternately.

[0023] S3. Arrange at least two cells horizontally and weld the connecting parts of the tabs of the two cells close to each other. Then stack multiple welded cells vertically and install an end plate at the end of the two cells facing away from each other. The laser of the laser welder passes through the welding groove on the end plate to weld and fix the connecting parts of two adjacent cells in the vertical direction, thus completing the forming of a single battery module. Repeat this operation until a preset number of battery modules are completed.

[0024] S4. Fix the frame to the fixture, and then push one or more battery modules in the same cavity into the cavity along the third direction. During the pushing process, use a glue gun to apply structural glue or sealant to the outer wall of the battery module along the vertical third direction so that a uniform adhesive layer is formed on the surface when it enters the cavity. Repeat this operation until all battery modules are installed.

[0025] S5, place and fix the pressure plate on the battery module, fix the first cover plate to the opening end face of the corresponding side of the frame, rotate the entire semi-assembly 180° along the horizontal axis so that the other side of the battery module faces upward; place another pressure plate on the other side of the battery module for fixation; install and fix the second cover plate to the other opening end face of the frame.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] 1. In this invention, the housing includes a frame, which includes multiple side beams. The multiple side beams are detachably connected in sequence and enclose a cavity. Each side beam has a first region near the cavity and a second region located on the side of the first region away from the cavity. At least one side beam has an installation channel extending along its own length and located within the second region, and the installation channel has a built-in medium manifold. Multiple heat management plates are vertically and spaced apart in the cavity. The two ends of each heat management plate are respectively connected to the inner walls of two oppositely arranged side beams, and each heat management plate has a medium flow channel communicating with the medium manifold. This design achieves deep integration of the cooling system and the supporting structure. It not only completely removes the manifold structure from the core layout space of the battery pack, significantly improving the internal space utilization and volumetric energy density, but also avoids interference with the medium flow when the installation channel is deformed under stress by independently setting the medium manifold and the installation channel. At the same time, the vertically arranged heat management plates are attached to the side wall of the battery cell, achieving efficient and uniform heat dissipation along the height direction, effectively alleviating the temperature gradient problem caused by the traditional bottom-mounted liquid cooling structure.

[0028] 2. In this invention, the side beam includes two first side beams arranged opposite each other along a first direction of the shell. Each of the two first side beams is provided with an installation channel and multiple first filling channels. The multiple first filling channels are located in a second region, spaced apart along the periphery of the side of the installation channel facing away from the first region, and extending along the length of the first side beam. The first filling channels are filled with reinforcing adhesive. This design compensates for the strength loss of the side beam body caused by the installation channels, significantly enhancing the bending, torsional, and overall load-bearing capacity of the side beam. Simultaneously, the filling with reinforcing adhesive not only strengthens the structure but also provides sealing and cushioning functions, significantly improving the structural reliability and durability of the battery pack under complex conditions such as vibration and impact.

[0029] 3. In this invention, the cross-sectional area of ​​the mounting channel is larger than that of the dielectric manifold, and the first region is provided with at least one vent hole with both ends communicating with the mounting channel and the accommodating cavity respectively. This design, on the one hand, provides sufficient clearance for the assembly of the dielectric manifold, facilitating installation operations, and can effectively accommodate thermal expansion deformation caused by temperature changes, reducing assembly stress and the risk of fatigue cracking during long-term use; on the other hand, when the battery module experiences thermal runaway, the high-temperature gas generated in the accommodating cavity can enter the mounting channel through the vent hole and be discharged along its length, thereby achieving directional pressure relief and gas venting; during this process, the built-in dielectric manifold can also indirectly cool the high-temperature gas flowing through the mounting channel, playing a certain role in cooling and suppressing explosion, further improving the safety protection capability and multi-functional integration level of the battery pack. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a battery pack according to the present invention.

[0031] Figure 2 This is a cross-sectional view of a battery pack according to the present invention.

[0032] Figure 3 This is an exploded view of a battery pack according to the present invention.

[0033] Figure 4 This is a partial structural diagram of a battery pack according to the present invention.

[0034] Figure 5 This is a partial exploded view of the structure of a battery pack according to the present invention.

[0035] Figure 6 for Figure 4 A structural diagram from another perspective.

[0036] Figure 7 for Figure 6 Sectional view at point AA.

[0037] Figure 8 for Figure 6 Sectional view at point BB.

[0038] Figure 9 This is a schematic diagram of the battery module in this invention.

[0039] Figure 10 This is a schematic diagram of the structure of the first side beam in this invention.

[0040] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically:

[0041] 100. Frame; 101. Receiving cavity; 102. First area; 103. Second area; 104. Medium manifold; 104a. Input manifold; 104b. Output manifold; 110. First side beam; 111. Mounting channel; 111a. Partition; 111b. Upper channel; 111c. Lower channel; 112. First filling channel; 113. Vent hole; 114. First through hole; 115. Second through hole; 116. Mounting groove; 120. Second side beam; 121. Second filling channel; 122. Medium input connector; 123. Medium output connector; 200. Thermal management plate; 201. First thermal management plate; 202. Second thermal management plate; 203. Protrusion; 210. Medium flow channel; 211. Input medium flow channel; 212. Output medium flow channel; 300. Reinforcing adhesive; 400. First connector; 410. Second connector; 500, Control system module; 510, Copper busbar; 520, Flexible circuit board; 600, Battery module; 610, Battery cell; 611, Connecting part; 620, End plate; 621, Welding groove; 622, Positive input terminal; 623, Negative input terminal; 624, Elastic bending part; 630, Buffer component; 700, First cover plate; 710, Second cover plate; 730, Pressure plate; 731, Positioning groove; 740, Adapter plate; 800, Recessed area; 810, First cavity; 820, Second cavity. Detailed Implementation

[0042] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0044] Furthermore, in this invention, descriptions involving terms such as "first," "second," and "a" are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0047] like Figures 1 to 10 As shown, in this embodiment, a battery pack includes:

[0048] The housing includes a frame 100, which includes a plurality of side beams. The plurality of side beams are detachably connected in sequence and enclose a cavity 101. Each side beam has a first region 102 close to the cavity 101 and a second region 103 located on the side of the first region 102 away from the cavity 101. At least one side beam is provided with an installation channel 111 extending along its own length direction and located in the second region 103, and the installation channel 111 has a built-in medium manifold 104.

[0049] Multiple thermal management plates 200 are vertically and spaced apart within the accommodating cavity 101. Each thermal management plate 200 has its two ends connected to the inner walls of two oppositely arranged side beams, and each thermal management plate 200 has a medium flow channel 210 communicating with the medium manifold 104. This design achieves deep integration of the cooling system and the supporting structure. It not only completely removes the manifold structure from the core layout space of the battery pack, significantly improving internal space utilization and volumetric energy density, but also avoids interference with medium flow caused by the independent arrangement of the medium manifold 104 and the mounting channel 111 under stress and deformation. Simultaneously, the vertically arranged thermal management plates 200 are in contact with the sidewalls of the battery cell 610, achieving efficient and uniform heat dissipation along the height direction, effectively mitigating the temperature gradient problem caused by traditional bottom-mounted liquid cooling structures.

[0050] Specifically, such as Figures 1 to 10As shown, in this embodiment, the battery pack mainly includes a housing, a thermal management plate 200, a battery module 600, and a communication module. The housing is a split structure, formed by a frame 100 and a first cover plate 700 and a second cover plate 710 detachably disposed on opposite sides of the frame 100, to form a closed accommodating cavity 101 for accommodating the thermal management plate 200, the battery module 600, and other functional components.

[0051] Furthermore, the frame 100 is composed of multiple side beams, preferably four side beams connected end to end in sequence to form a rectangular accommodating cavity 101, which serves as the main frame of the battery pack. Each side beam is fixed by welding or other reliable connection methods, and each side beam has two adjacent functional areas, namely a first area 102 close to the accommodating cavity 101 and a second area 103 located on the side of the first area 102 away from the accommodating cavity 101.

[0052] To improve the utilization of the internal space of the battery pack and achieve efficient cooling without affecting the arrangement of the battery cells 610, this embodiment provides an installation channel 111 extending along its length in the second region 103 of at least one side beam. An independent medium manifold 104 is embedded within this installation channel 111 to collect the cooling medium and distribute it to each thermal management plate 200. By arranging the medium manifold 104 in the second region 103 of the side beam away from the receiving cavity 101, the cooling system's manifold does not need to occupy the battery cell 610 arrangement area, thus effectively avoiding encroachment on the effective volume and significantly improving the volumetric energy density and overall compactness of the battery pack. Furthermore, the medium manifold 104 is placed inside the installation channel 111 as an independent pipe, rather than directly utilizing the installation channel 111 as a fluid channel. Compared to the solution of using the installation channel 111 itself as a flow channel, it can effectively isolate the impact of local deformation of the side beam caused by external load, thermal deformation or manufacturing tolerance on the flow of cooling medium, ensuring the stability of the flow channel cross section and controllable flow resistance; at the same time, the independent pipeline structure also facilitates later maintenance, replacement or upgrade, improving the maintainability and long-term operational reliability of the system.

[0053] Furthermore, the side beam includes two first side beams 110 arranged opposite each other along the first direction of the shell, serving as the long side of the frame 100. Each of the two first side beams 110 is provided with an installation channel 111 and multiple first filling channels 112. The multiple first filling channels 112 are located in the second region 103, spaced apart along the periphery of the side of the installation channel 111 facing away from the first region 102, and extending along the length of the first side beam 110. The first filling channels 112 are filled with reinforcing adhesive 300. This design compensates for the strength loss of the side beam body caused by the installation channel 111, significantly enhancing the bending, torsional, and overall load-bearing capacity of the side beam. Simultaneously, the filling with reinforcing adhesive 300 not only strengthens the structure but also provides sealing and cushioning functions, significantly improving the structural reliability and durability of the battery pack under complex conditions such as vibration and impact.

[0054] Furthermore, the reinforcing adhesive 300 can be selected from at least one of epoxy resin adhesive, polyurethane structural adhesive, silicone sealant, modified acrylic adhesive, or thermosetting composite adhesive.

[0055] Furthermore, in the two first side beams 110 arranged opposite each other along the first direction of the housing (i.e., the direction indicated by arrow X in the figure), their respective mounting channels 111 can be configured differently according to functional requirements. In a preferred embodiment, the medium manifold 104 is arranged only in the mounting channel 111 of one first side beam 110, while the electrical connection structure, such as high-voltage wiring harness, low-voltage signal cable, or copper busbar 510, is integrated in the mounting channel 111 of the other first side beam 110. This design makes full use of the redundant space in the second region 103 of the side beam to achieve the partitioned layout of cooling pipes and electrical systems, which not only avoids mutual interference between fluid pipes and conductive components, but also improves the functional integration and assembly neatness inside the battery pack, while facilitating later maintenance and fault isolation.

[0056] In another embodiment, two sets of medium manifolds 104 are respectively installed in the mounting channels 111 of the two first side beams 110, one set for the input of cooling medium and the other set for the output of cooling medium, thereby forming independent inlet and return liquid flow channel systems. This layout helps to optimize the flow field distribution, reduce flow resistance, and improve the circulation efficiency of the thermal management system.

[0057] Preferably, the two first side beams 110 have the same structure and are symmetrically designed, which not only facilitates mold development and mass production and reduces production costs, but also ensures the balance of the battery pack in terms of stress and thermal management performance on both sides, and improves the overall structural stability and system consistency.

[0058] Furthermore, the cross-sectional area of ​​the mounting channel 111 is larger than that of the medium manifold 104, and the first region 102 is provided with at least one vent hole 113 with both ends communicating with the mounting channel 111 and the accommodating cavity 101 respectively. This design, on the one hand, provides sufficient clearance for the medium manifold 104 during assembly, facilitating pipe insertion and positioning, and effectively accommodates thermal expansion deformation caused by changes in operating temperature, thereby significantly reducing assembly stress and the risk of fatigue cracking due to repeated thermal cycling during long-term service; on the other hand, under extreme conditions (such as thermal runaway of the battery module 600), the high-temperature and high-pressure gas generated in the accommodating cavity 101 can enter the mounting channel 111 through the vent hole 113 and be orderly discharged along its length, realizing directional pressure relief and gas venting, and avoiding sudden local pressure rise that could cause shell rupture or a chain reaction.

[0059] Furthermore, since the dielectric manifold 104 is built into and runs through the installation channel 111, when high-temperature gas flows through the installation channel 111, it can exchange heat with the outer wall of the dielectric manifold 104, thereby indirectly cooling the gas. This process helps to reduce the temperature of the discharged gas, slow down the rate of heat spread, and to a certain extent play a role in cooling and suppressing explosion, further improving the battery pack's safety protection capability and multi-functional integration level in thermal runaway scenarios.

[0060] Preferably, the vent 113 is circular to facilitate processing and reduce stress concentration; multiple vents 113 are distributed in a matrix along the length of the inner wall of the first side beam 110 to ensure that gas can be uniformly and quickly introduced into the installation channel 111 from different areas of the accommodating cavity 101, thereby improving the depressurization efficiency and the reliability of thermal runaway response.

[0061] Furthermore, at least one or both ends of the mounting channel 111 are connected to the external environment along its length, and a detachable explosion relief valve is provided at at least one or both ends. Under normal operating conditions, the explosion relief valve remains sealed to ensure the airtightness of the cooling system and the interior of the housing. When abnormally high pressure is generated inside the battery pack due to extreme conditions such as thermal runaway, the explosion relief valve can automatically open to quickly release the high-temperature gas accumulated in the mounting channel 111, achieving rapid pressure relief and preventing the housing structure from rupturing or exploding due to a sudden increase in pressure.

[0062] Since the installation channel 111 itself serves as a gas evacuation path (connected to the accommodating cavity 101 via the exhaust port 113), the explosion relief valve at its end forms a complete directional pressure relief channel: "inside the accommodating cavity 101 → exhaust port 113 → installation channel 111 → explosion relief valve → outside," effectively guiding high-temperature harmful gases away from the battery cell 610 area and ensuring their orderly discharge. Furthermore, the explosion relief valve features a detachable connection, facilitating regular inspection, cleaning, or replacement, thus balancing safety and maintenance convenience.

[0063] In this embodiment, a horizontally arranged partition 111a is provided within the installation channel 111, dividing the installation channel 111 into an independent upper channel 111b and a lower channel 111c. The medium manifold 104 includes an input manifold 104a located in the upper channel 111b and an output manifold 104b located in the lower channel 111c. The cross-sectional area of ​​the upper channel 111b is larger than that of the input manifold 104a, and the cross-sectional area of ​​the lower channel 111c is larger than that of the output manifold 104b. This design achieves physical isolation between the inlet and outlet flow channels through the partition 111a, effectively avoiding thermal interference and flow crosstalk between the input and output cooling media. This is beneficial for maintaining stable temperature difference drive and circulating pressure difference, thereby improving the overall efficiency and temperature uniformity of the thermal management system. Meanwhile, the pre-reserved assembly gaps in the upper and lower channels 111c not only facilitate the installation and positioning of the input manifold 104a and the output manifold 104b, but also effectively absorb thermal expansion deformation caused by temperature changes, reducing pipeline stress concentration and the risk of fatigue failure during long-term operation. Furthermore, the independent compartment structure also facilitates subsequent maintenance, inspection, or pipeline replacement, further enhancing the system's serviceability and reliability.

[0064] Furthermore, the first region 102 of the first side beam 110 is also provided with a plurality of first through holes 114 and second through holes 115 arranged at intervals along the length of the first side beam 110. The two ends of the plurality of first through holes 114 are respectively connected to the upper channel 111b and the accommodating cavity 101, and the two ends of the plurality of second through holes 115 are respectively connected to the lower channel 111c and the accommodating cavity 101, for the joints of the medium flow channel 210 connecting the heat management plate 200 to pass through.

[0065] Furthermore, each thermal management plate 200 has a medium flow channel 210 corresponding to a first through hole 114 and a second through hole 115. The medium flow channel 210 includes at least one input medium flow channel 211 and an output medium flow channel 212. The input medium flow channel 211 of each thermal management plate 200 is connected to the input manifold 104a through the first through hole 114 via the first connector 400, and the output medium flow channel 212 is connected to the output manifold 104b through the second through hole 115 via the second connector 410. With the above structure, the cooling medium can enter the input medium flow channel 211 of the thermal management plate 200 from the input manifold 104a through the first connector 400, complete the heat exchange with the battery cell 610 through the thermal management plate 200, and then flow back to the output manifold 104b from the output medium flow channel 212 through the second connector 410, thereby forming an independent, orderly and low-interference closed-loop cooling circuit. This design not only achieves precise liquid supply and efficient heat dissipation for each thermal management plate 200, but also avoids the space congestion and assembly difficulties caused by traditional centralized piping, significantly improving the modularity, connection reliability and ease of maintenance of the cooling system.

[0066] Furthermore, at least one first side beam 110 has a U-shaped mounting groove 116 on the side of the first region 102 facing the receiving cavity 101. The mounting groove 116 extends along the length of the first side beam 110 and is recessed towards the second region 103, forming a limiting structure with an opening facing the interior of the receiving cavity 101, used for positioning and limiting the flexible circuit board 520 (i.e., flexible circuit board). This design provides a stable and reliable installation path for the flexible circuit board 520 by integrating a dedicated wiring channel on the first side beam 110, effectively preventing it from shifting, bending, or wearing during vehicle vibration, assembly, or use, thereby ensuring the stability of signal transmission and the reliability of electrical connections. At the same time, the U-shaped cross-section structure facilitates the insertion and fixation of the flexible circuit board 520 without the need for additional brackets or binding parts, simplifying the internal wiring process and improving assembly efficiency and space cleanliness.

[0067] It is worth noting that the flexible circuit board 520 is typically made of flexible polymer materials such as polyimide, which has relatively limited high-temperature resistance. In extreme conditions such as thermal runaway of the battery pack, the flexible circuit board 520 can rapidly melt or decompose under high temperatures, thus forming a temporary passage in the exhaust path that was originally partially blocked. This characteristic helps ensure that high-temperature, high-pressure gases can smoothly enter the installation channel 111 through the exhaust port 113 and be discharged directionally along a preset path, avoiding pressure relief obstruction due to blockage by the flexible circuit board 520, thereby improving the reliability of explosion relief and overall safety of the battery pack under thermal runaway conditions.

[0068] In this embodiment, the side beams also include two second side beams 120 arranged opposite each other along the second direction of the housing (i.e., the direction indicated by arrow Y in the figure). The second side beams 120 are perpendicularly connected to the first side beam 110, serving as the short side of the frame 100. At least one second side beam 120 has a medium flow channel 210 in its first region 102, communicating with the medium manifold 104, for introducing or discharging the cooling medium. This design integrates some cooling functions within the second side beams 120, not only expanding the coverage of the thermal management system, especially suitable for temperature control of the end cells 610 in long battery packs, but also further improving the functional integration of the housing structure, avoiding the need for additional external piping, and helping to maintain the simplicity and compactness of the internal layout.

[0069] Furthermore, the second region 103 of the second side beam 120 is provided with a plurality of second filling channels 121 spaced apart along the height direction of the shell, and each second filling channel 121 is filled with reinforcing adhesive 300. This design effectively compensates for the cross-sectional weakening caused by the opening of the medium flow channel 210, and significantly enhances the bending stiffness and overall structural strength of the second side beam 120 under vertical and lateral loads. At the same time, the filling reinforcing adhesive 300 has sealing, vibration damping and buffering functions, which can improve the battery pack's ability to cope with vibration, impact and complex mechanical stress during vehicle operation, thereby enhancing the structural reliability and long-term service durability of the entire pack.

[0070] Furthermore, at least one second side beam 120 is detachably provided with a medium inlet connector 122 and a medium outlet connector 123 that communicate with an external cooling system. The medium inlet connector 122 communicates with the inlet manifold 104a for introducing the cooling medium; the medium outlet connector 123 communicates with the outlet manifold 104b for discharging the cooled medium after heat exchange. This design integrates the interface between the battery pack and the external thermal management system onto the second side beam 120 of the frame 100 structure, facilitating pipe connection during vehicle layout.

[0071] In this embodiment, the first cover plate 700 and the second cover plate 710 are symmetrically arranged vertically along the two opening sides of the frame 100. The first cover plate 700 and the second cover plate 710 are preferably made of aluminum alloy, which effectively reduces the overall weight of the battery pack while ensuring structural strength, thus improving the vehicle's energy efficiency and range. The periphery of the first cover plate 700 and the second cover plate 710 is reliably connected to the frame 100 by fasteners (such as bolts, rivets, or self-tapping screws), achieving a sealed enclosure of the accommodating cavity 101 and ensuring the protective performance of the internal components under complex operating conditions.

[0072] Furthermore, a rectangular pressure plate 730 is provided between the first cover plate 700 and / or the second cover plate 710 and the battery module 600. The size of the pressure plate 730 is adapted to the size of the first cover plate 700 and the second cover plate 710. It is preferably made of steel (such as cold-rolled steel plate) and has high rigidity and compressive strength. It is used to apply axial preload to the battery module 600 and components such as the thermal management plate 200 and electrical modules in the accommodating cavity 101 to prevent them from shifting or loosening during transportation, vibration or thermal expansion, thereby providing effective mechanical protection and structural constraint.

[0073] The pressure plate 730 is provided with multiple rectangular positioning slots 731 that interlock with the heat management plate 200, which are used to accurately position and limit the heat management plate 200 to avoid assembly deviations or shaking during operation.

[0074] Furthermore, the pressure plate 730, on the side facing away from the battery module 600, is also provided with multiple strip-shaped adapter plates 740. The adapter plates 740 are welded to the thermal management plate 200 through the protrusions 203 of the positioning groove 731. The adapter plates 740 are preferably made of aluminum alloy, which provides good welding compatibility with the thermal management plate 200, which is also made of aluminum. After the protrusions 203 of the thermal management plate 200 pass through the positioning groove 731 on the pressure plate 730, they are fixedly connected to the adapter plates 740 by laser welding, friction stir welding, or other reliable welding processes, thereby achieving a strong mechanical connection between the thermal management plate 200 and the pressure plate 730. Compared to the traditional method of directly fixing the pressure plate 730 to the heat management plate 200 with screws, this design significantly increases the effective connection area between the heat management plate 200 and the pressure plate 730. This not only improves the overall vibration resistance and fatigue resistance of the structure but also enhances the heat conduction path between them, facilitating heat diffusion from the heat management plate 200 to the pressure plate 730 and the cover plate, thereby improving local heat dissipation efficiency. Simultaneously, the welded connection avoids problems such as loose fasteners, corrosion, or stress concentration, improving long-term reliability and safety, and simplifying the assembly process, which is beneficial for automated production.

[0075] Furthermore, a reinforcing adhesive 300 (not shown in the figure) or a thermal insulation component (not shown in the figure) is provided between the pressure plate 730 and the first cover plate 700 and / or the second cover plate 710. Preferably, a high-strength structural reinforcing adhesive 300 is used. This reinforcing adhesive 300 fills the gap between the pressure plate 730 and the cover plate, forming a reliable adhesive sealing layer to improve the overall airtightness and dustproof and waterproof performance of the casing. On the other hand, when the battery module 600 undergoes thermal expansion due to charging / discharging or changes in ambient temperature, the reinforcing adhesive 300 provides a certain buffering and restraining effect, effectively suppressing stress concentration caused by excessive expansion of the battery module 600 on the casing structure, thereby improving the structural stability and long-term safety of the battery pack.

[0076] Furthermore, the first cover plate 700 and / or the second cover plate 710 have multiple recessed areas 800 on the side opposite to the battery module 600. Each recessed area 800 includes a first cavity 810 and a second cavity 820 with different recess depths. The bottom surface of the first cavity 810 abuts against the pressure plate 730, and there is a gap between the bottom surface of the second cavity 820 and the pressure plate 730. This design achieves multiple functions by constructing a two-stage cavity structure with a height difference inside the cover plate: on the one hand, the bottom surface of the first cavity 810 serves as the main support surface, forming a surface contact with the pressure plate 730, which is used to accurately position and axially limit the installation position of the first cover plate 700 and the second cover plate 710 during the assembly process, ensuring that the first cover plate 700 and the second cover plate 710 are subjected to uniform force and maintain the overall dimensional stability of the housing; on the other hand, the second cavity 820, due to the gap between it and the pressure plate 730, can serve as an injection and filling space for the reinforcing adhesive 300. During assembly, reinforcing adhesive 300 can be injected into the second cavity 820 through this gap. After the adhesive cures, it not only enhances the connection strength between the cover plate and the pressure plate 730, but also forms an effective sealing layer, improving the dustproof, waterproof and vibration-resistant performance of the battery pack.

[0077] Preferably, the first cavity 810 and the second cavity 820 are coaxially arranged, meaning they have the same central axis in the thickness direction of the cover plate. This coaxial arrangement not only facilitates mold processing and molding process control, but also ensures the uniform distribution of the reinforcing adhesive 300 in the second cavity 820 and the centering contact between the pressure plate 730 and the bottom surface of the first cavity 810, further improving assembly accuracy, structural symmetry, and stress uniformity, which is beneficial for the battery pack to maintain stable sealing performance and mechanical integrity during long-term service.

[0078] In this embodiment, multiple thermal management plates 200 are all strip-shaped and arranged vertically, spaced apart and equidistantly along the second direction of the housing within the accommodating cavity 101, thereby dividing the entire accommodating cavity 101 into multiple independent sub-cavities. Each sub-cavity can accommodate a group of battery modules 600, realizing the partitioned arrangement and independent thermal management of multiple groups of battery modules 600.

[0079] Each thermal management plate 200 is connected at both ends to the inner walls of two oppositely arranged first side beams 110 via fasteners (such as bolts, rivets, or snap-fit ​​structures) to ensure stable installation and facilitate maintenance and replacement. Simultaneously, each thermal management plate 200 has a media flow channel 210 inside, which is connected to a media manifold 104 located within the first side beam 110 via a pipe joint, allowing cooling media to flow into and through the thermal management plate 200, achieving efficient and uniform heat dissipation from the side walls of adjacent battery modules 600.

[0080] Furthermore, the multiple thermal management plates 200 include a first thermal management plate 201 and a second thermal management plate 202 with different thicknesses. The first thermal management plate 201 and the second thermal management plate 202 are arranged alternately and at intervals along the second direction of the housing, and are detachably connected to two oppositely arranged first side beams 110 by fasteners. Because the first thermal management plate 201 and the second thermal management plate 202 have different thicknesses, the occupancy of the effective space inside the accommodating cavity 101 can be effectively reduced while meeting the requirements of structural strength and heat dissipation performance, thereby improving the overall space utilization efficiency of the battery pack.

[0081] Furthermore, an electrical mounting area is formed between the first thermal management board 201 or the second thermal management board 202 and at least one second side beam 120 for integrating and arranging battery management system (BMS) modules, relays, current sensors, communication units or other electrical or electronic functional components, thereby realizing the functional zoning and coordinated layout of the cell 610 module, thermal management system and electrical control system, and improving the overall integration and space utilization efficiency of the battery pack.

[0082] Furthermore, a control system module 500 is provided in the electrical installation area. This control system module 500 includes, but is not limited to, electrical or electronic components such as a battery management system (BMS) module, relays, current sensors, and communication units. The control system module 500 abuts against the side surface of the first thermal management plate 201 or the second thermal management plate 202, thereby obtaining stable mechanical support and utilizing the metal thermal management plate 200 to assist in heat dissipation, improving the operational reliability of electronic components under high load or high temperature conditions.

[0083] Furthermore, the control system module 500 has a copper busbar 510 electrically connected to the battery module 600 and / or a flexible circuit board 520 communicatively connected to the battery module 600. The copper busbar 510 is attached to the inner wall of the first side beam 110, using the first side beam 110 as a heat dissipation path to effectively improve the heat dissipation efficiency of the conductive components. Thanks to good thermal management, the cross-sectional area or overall size of the copper busbar 510 can be appropriately reduced while meeting current carrying capacity and temperature rise requirements, thereby reducing material usage and production costs. Meanwhile, the flexible circuit board 520 is secured within the mounting groove 116 on the first side beam 110, achieving reliable positioning and preventing loosening, thus avoiding signal connection failure due to vibration, thermal cycling, or assembly stress.

[0084] In addition, the adoption of the flexible PCB 520 to replace the traditional discrete wire harness solution not only significantly reduces the number of connectors and wiring space, but also avoids risks such as loosening of connectors, oxidation or contact failure, and significantly improves the system's integration, electromagnetic compatibility and long-term service safety.

[0085] In this embodiment, at least one set of battery modules 600 is included, located between two adjacent thermal management plates 200 or between a side beam arranged along the first direction of the housing and a thermal management plate 200. Preferably, multiple sets of battery modules 600 are provided, some of which are housed in the cavity between two adjacent first thermal management plates 201 and second thermal management plates 202, and some are located in the cavity between the second side beam 120 and the first thermal management plate 201 or the second thermal management plate 202, thereby making full use of the entire effective area within the accommodating cavity 101 and improving the energy density and layout flexibility of the battery pack.

[0086] Furthermore, the battery module 600 includes multiple battery cells 610 and two end plates 620. The multiple battery cells 610 are stacked in at least two rows and two columns to form a battery cell group 610. The two end plates 620 are respectively located at both ends of the battery cell group 610, thereby forming a modular battery unit with a stable structure that is easy to assemble and replace. This modular design not only facilitates standardized production and rapid integration, but also allows for flexible arrangement and independent maintenance within the battery pack.

[0087] Furthermore, each battery cell 610 has a connecting portion 611 bent vertically at both ends. When multiple battery cells 610 are stacked, the connecting portions 611 of two adjacent battery cells 610 (top and bottom, or left and right) fit together to form a reliable electrical connection interface. Compared with the conventional structure where the tabs extend horizontally and are laser-welded vertically from top to bottom, this embodiment bends the tabs vertically so that the connecting portion 611 is located on the side of the battery cell 610, and completes the connection by lateral welding. This effectively reduces the space occupied, thus making it more conducive to achieving high volume utilization and compact integration.

[0088] Specifically, for two adjacent rows of cells 610, the bending directions of their tabs are opposite to each other (i.e., the connecting portion 611 of the upper cell 610 bends downwards, and the connecting portion 611 of the lower cell 610 bends upwards), so that the connecting portions 611 of the two cells are close to each other in the vertical direction and form a face-to-face contact, thereby forming a low-impedance parallel or series electrical connection path. For two adjacent columns of cells 610, the bending directions of their tabs are the same (e.g., both bend upwards or both bend downwards), so that the connecting portions 611 of the adjacent cells 610 are in a back-to-back contact state, that is, the outer surfaces of the two connecting portions 611 are in contact with each other, and the electrical connection is achieved by external welding.

[0089] Correspondingly, each end plate 620 of the battery module 600 has at least one strip welding groove 621 that penetrates through itself and is opposite to a connecting part 611. During assembly, the laser beam can pass through the strip welding groove 621 and directly act on the internally fitted connecting part 611 to achieve high-precision, non-contact penetration welding. This design, on the one hand, flexibly adapts to the electrical connection requirements in the multi-dimensional cell arrangement by differentially controlling the bending direction of the tabs, achieving high-density, low-impedance internal interconnection within a limited space; on the other hand, while maintaining the structural clamping function, the end plate 620 provides a process channel for internal connection by integrating the strip welding groove 621, allowing high-quality welding to be completed without exposing the electrode posts or disassembling the end plate 620. This ensures the mechanical integrity and sealing of the module, supports automated and highly consistent manufacturing processes, and significantly improves the reliability, production efficiency, and safety of the battery module 600.

[0090] Furthermore, the battery module 600 also includes a buffer 630 disposed between two adjacent battery cells 610 arranged along the stacking direction. The buffer 630 is made of an elastic or compressible material (such as foam, silicone, or polymer foam) and is used to absorb the mechanical stress generated by the expansion of the battery cell 610 during charge and discharge cycles, alleviate the thermal coupling effect, prevent deformation of the battery cell 610 casing or damage to the internal structure, and at the same time improve the overall shock resistance and long-term service stability of the module.

[0091] Furthermore, at least one end plate 620 is provided with a positive input terminal 622 and a negative input terminal 623 for realizing the electrical connection between the battery module 600 and the external circuit. The positive input terminal 622 and the negative input terminal 623 have elastic bending portions 624, which give the terminals a certain degree of flexibility and resilience through a preset bending structure. This design offers significant advantages during assembly: when assembling the cells 610 one by one onto the end plate 620, the elastic bending portion 624 can be temporarily bent towards the side of the end plate 620 away from the cells 610 (i.e., outwards) to avoid interference with the cells 610, tabs, or other internal components during installation; after all the cells 610 are stacked and fixed to the end plate 620, the elastic bending portion 624 is bent in the opposite direction towards the side of the end plate 620 closer to the cells 610 (i.e., inwards) so that it fits against the inside of the end plate 620 or aligns with the corresponding connecting portion 611 for subsequent welding or connection.

[0092] The flexible bending part 624 not only effectively solves the space conflict problem between the terminals and the battery cell 610 under high-density arrangement, but also significantly saves the installation space inside the module and improves assembly efficiency and process tolerance.

[0093] This invention also provides a method for assembling a battery pack, comprising the following steps:

[0094] S1, two first side beams 110 arranged opposite each other along the first direction of the shell and two second side beams 120 arranged opposite each other along the second direction of the shell are connected end to end in sequence to form a frame 100 with a receiving cavity 101, and each side beam is fixed by welding to form the main frame of the battery pack.

[0095] S2, multiple first heat management plates 201 and second heat management plates 202 of different thicknesses are installed at intervals along the length direction of the frame 100, so that multiple cavities are formed inside the frame 100, and the first heat management plates 201 and second heat management plates 202 are arranged alternately.

[0096] S3, arrange at least two battery cells 610 in the horizontal direction, and attach and weld the connecting parts 611 of the tabs of the two battery cells 610 close to each other. Then stack multiple welded battery cells 610 in the vertical direction, and install an end plate 620 at the end of the two battery cells 610 facing away from each other. Then, let the laser of the laser welder pass through the welding groove 621 on the end plate 620 to weld and fix the connecting parts 611 of two adjacent battery cells 610 in the vertical direction, thereby completing the forming of a single battery module 600. Repeat this operation until a preset number of battery modules 600 are completed.

[0097] S4. Fix the frame 100 to the fixture, and then push one or more battery modules 600 in the same cavity into the cavity in a third direction (i.e., the direction shown by arrow Z in the figure). During the pushing process, use a glue gun to apply structural adhesive or sealant to the outer wall of the battery module 600 in a direction perpendicular to the third direction, so that a uniform adhesive layer is formed on the surface when it enters the cavity. Repeat this operation until all battery modules 600 are installed.

[0098] S5, place and fix the pressure plate 730 on the battery module 600. Then, fix the first cover plate 700 to the opening end face of the corresponding side of the frame 100. After completing the above operations, rotate the entire semi-assembly 180° along the horizontal axis so that the other side of the battery module 600 faces upward. Next, place another pressure plate 730 on the other side of the battery module 600 and fix it in the same way. Finally, install and fix the second cover plate 710 to the other opening end face of the frame 100, thereby completing the sealing and structural integration of the entire battery pack.

[0099] This assembly method, through a process combining modular prefabrication, directional insertion, and simultaneous adhesive application, significantly improves assembly efficiency and consistency. At the same time, it ensures the positioning accuracy, structural sealing, and thermo-mechanical synergy of the battery module, making it suitable for the large-scale manufacturing of power battery systems with high energy density and high safety requirements.

Claims

1. A battery pack, characterized in that, include: The housing includes a frame, the frame includes a plurality of side beams, the plurality of side beams together form a receiving cavity, each side beam has a first region close to the receiving cavity and a second region located on the side of the first region away from the receiving cavity, at least one side beam is provided with an installation channel extending along its own length direction and located in the second region, and the installation channel has a built-in medium manifold. Multiple heat management plates are vertically and spaced apart in the accommodating cavity. The two ends of each heat management plate are respectively connected to the inner walls of two oppositely arranged side beams, and each heat management plate has a medium flow channel communicating with the medium manifold. The side beam includes two first side beams arranged opposite to each other along a first direction of the shell; The side beam further includes two second side beams arranged opposite to each other along the second direction of the shell. The second side beams are connected to the first side beam. At least one second side beam has a medium flow channel communicating with the medium manifold in the first region. The medium flow channel is located in the first region of the second side beam. The second region of the second side beam has a plurality of second filling channels arranged at intervals along the height direction of the shell. The second filling channels are filled with reinforcing adhesive. The plurality of thermal management plates include a first thermal management plate and a second thermal management plate of different thicknesses. The first thermal management plate and the second thermal management plate are arranged alternately and at intervals along the second direction of the housing and connected to two oppositely arranged first side beams. An electrical installation area is formed between the first thermal management plate or the second thermal management plate and at least one second side beam. At least one of the first side beams has a mounting groove on the side of the first region facing the receiving cavity, the mounting groove extending along the length of the first side beam and recessed toward the second region.

2. The battery pack according to claim 1, characterized in that, Each of the two first side beams is provided with the installation channel and multiple first filling channels. The multiple first filling channels are located in the second region and are arranged at intervals along the periphery of the side of the installation channel away from the first region, and extend along the length direction of the first side beam. The first filling channels are filled with reinforcing adhesive.

3. A battery pack according to claim 1, characterized in that, The cross-sectional area of ​​the installation channel is larger than that of the medium manifold, and the first region is provided with at least one vent hole with both ends communicating with the installation channel and the accommodating cavity respectively.

4. A battery pack according to claim 2, characterized in that, The installation channel is provided with a partition, which divides the installation channel into an independent upper channel and a lower channel. The medium manifold includes an input manifold in the upper channel and an output manifold in the lower channel. The cross-sectional area of ​​the upper channel is larger than that of the input manifold, and the cross-sectional area of ​​the lower channel is larger than that of the output manifold.

5. A battery pack according to claim 4, characterized in that, The first region of the first side beam is further provided with a plurality of first through holes and second through holes arranged at intervals along the length of the first side beam. The two ends of the plurality of first through holes are respectively connected to the upper channel and the accommodating cavity, and the two ends of the plurality of second through holes are respectively connected to the lower channel and the accommodating cavity.

6. A battery pack according to claim 5, characterized in that, Each of the heat management plates has a medium flow channel corresponding to a first through hole and a second through hole. The medium flow channel includes at least one input medium flow channel and an output medium flow channel. The input medium flow channel of each heat management plate is connected to the input manifold through the first through hole via a first connector, and the output medium flow channel is connected to the output manifold through the second through hole via a second connector.

7. A battery pack according to claim 1, characterized in that, The electrical installation area is provided with a control system module, which abuts against the first thermal management board or the second thermal management board, and has a copper busbar electrically connected to the battery module and / or a flexible board communicatively connected to the battery module, wherein the copper busbar is attached to the inner wall of the first side beam, and the flexible board is snapped into the mounting groove.

8. A battery pack according to claim 1, characterized in that, The battery module includes at least one set of battery modules, each battery module including multiple battery cells and two end plates. The multiple battery cells are stacked in at least two rows and two columns to form a battery cell group. The two end plates are respectively disposed at both ends of the battery cell group. Each battery cell has a tab at both ends with a connection portion bent in a vertical direction. When the multiple battery cells are stacked, the connection portions of two adjacent battery cells are attached to each other, and at least one welding groove is provided on the end plate that penetrates itself and is opposite to one of the connection portions.

9. A battery pack according to claim 8, characterized in that, The battery module further includes a buffer between two adjacent cells arranged along the stacking direction, and at least one end plate is provided with a positive input terminal and a negative input terminal, and the positive input terminal and the negative input terminal have elastic bending portions.

10. A battery pack according to claim 8, characterized in that, The housing also includes a first cover plate and a second cover plate detachably disposed on opposite sides of the frame. The first cover plate and the second cover plate cooperate to close the accommodating cavity. A pressure plate is also provided between the first cover plate and / or the second cover plate and the battery module. The pressure plate is provided with a plurality of positioning grooves that form an interlocking fit with the thermal management plate. A plurality of adapter plates are also provided on the side of the pressure plate away from the battery module. The adapter plates are welded to the protrusions of the thermal management plate that pass through the positioning grooves.

11. A battery pack according to claim 10, characterized in that, A reinforcing adhesive or heat-insulating component is provided between the pressure plate and the first cover plate and / or the second cover plate. The first cover plate and / or the second cover plate have multiple recessed areas on the side away from the battery module. Each recessed area includes a first cavity and a second cavity with different recessed depths. The bottom surface of the first cavity abuts against the pressure plate, and there is a gap between the bottom surface of the second cavity and the pressure plate.

12. A method for assembling a battery pack, comprising the battery pack according to any one of claims 1-11, characterized in that, Includes the following steps: S1, two first side beams arranged opposite each other along the first direction of the shell and two second side beams arranged opposite each other along the second direction of the shell are joined to form a frame, and the side beams are fixed by welding to form the main skeleton of the battery pack: S2, Multiple first heat management plates and second heat management plates of different thicknesses are arranged alternately in the frame to form multiple cavities in the frame, and the first heat management plates and second heat management plates are arranged alternately. S3. Arrange at least two cells horizontally and weld the connecting parts of the tabs of the two cells close to each other. Then stack multiple welded cells vertically and install an end plate at the end of the two cells facing away from each other. The laser of the laser welder passes through the welding groove on the end plate to weld and fix the connecting parts of two adjacent cells in the vertical direction, thus completing the forming of a single battery module. Repeat this operation until a preset number of battery modules are completed. S4. Fix the frame to the fixture, and then push one or more battery modules in the same cavity into the cavity along the axis of the frame. During the pushing process, use a glue gun to apply structural adhesive or sealant to the outer wall of the battery module in a direction perpendicular to the axis of the frame, so that a uniform adhesive layer is formed on the surface as it enters the cavity. Repeat this operation until all battery modules are installed. S5, place and fix the pressure plate on the battery module, fix the first cover plate to the opening end face of the corresponding side of the frame, rotate the entire semi-assembly 180° along the horizontal axis so that the other side of the battery module faces upward; place another pressure plate on the other side of the battery module for fixation; install and fix the second cover plate to the other opening end face of the frame.

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