Electric automobile and battery pack

Abstract

The electric automobile comprises a box body and a plurality of batteries placed in the box body, the box body comprises a frame and a baffle, the frame is arranged on the periphery of the batteries in a surrounding mode, at least one side opening of the baffle and at least one side opening of the frame are oppositely arranged, the frame and the baffle are fixedly connected through screws, the screws are at least partially embedded into the frame and the baffle, and the baffle is fixedly connected with the box body. The screw comprises a threaded section, the threaded section comprises a first branch threaded section and a second branch threaded section which are connected, the first branch threaded section is provided with a sealant layer to form a sealing section, and the sealing section is at least partially connected to the connecting position of the frame and the baffle; the frame is provided with a second boss, and the second boss protrudes out of the frame and is arranged on the periphery of the screw. The thread of the sealing section of the screw is at least partially connected to the second boss; the end, away from the baffle, of the sealing glue layer is lower than the second boss. According to the electric automobile and the battery pack, the sealing performance of the connecting position is improved, and the connecting strength of the connecting position is guaranteed.

Description

[0001] This application is a divisional application of application No. 202511233032.0, filed on September 1, 2025, entitled "Electric vehicle and battery pack". TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, in particular to an electric vehicle and a battery pack. BACKGROUND

[0003] The battery pack is used as an energy storage device and is increasingly widely used in life and industry. The battery pack includes a box body, which includes a bottom plate and a frame. The bottom plate and the frame are generally connected together by screws. The sealing performance of the screw connection has an important influence on the sealing reliability of the battery pack.

[0004] In the prior art, the connection holes are first opened on the bottom plate and the frame, and then the screws are connected in the connection holes to realize the connection of the bottom plate and the frame. An additional sealing structure is needed. The sealing performance of the screw connection position is not easy to meet the standard, and external water vapor or foreign matter can easily enter the battery pack through the screw connection position, causing the battery pack to fail to seal, and foreign matter or water vapor entering the battery pack can easily cause the battery pack to overheat. SUMMARY

[0005] Therefore, the present application provides a battery pack that improves the sealing performance of the connection position, ensures the connection strength of the connection position, reduces the probability of foreign matter entering the battery pack and causing the battery pack to overheat, and is safer to use.

[0006] The present application also provides an electric vehicle.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0008] A battery pack includes a box body and a plurality of batteries placed in the box body. The box body includes a frame and a baffle. The frame surrounds the outer periphery of the battery. The baffle and at least one side opening of the frame are oppositely arranged. The frame and the baffle are fixedly connected by a screw. The screw is at least partially embedded in the interior of the frame and the baffle. The screw includes a threaded segment. The threaded segment includes a first sub-thread segment and a second sub-thread segment connected. A sealing adhesive layer is arranged on the first sub-thread segment to form a sealing segment. The sealing segment is at least partially connected to the connection position of the frame and the baffle.

[0009] A second boss is arranged on the frame and protrudes from the frame and is arranged on the outer periphery of the screw. The threads of the sealing segment of the screw are at least partially connected to the second boss. The height of the end of the sealing adhesive layer away from the baffle is lower than that of the second boss.

[0010] From the above technical scheme can be seen, the battery pack provided by the application, by the first sub-thread segment on the screw is set to have a sealing glue layer sealing segment, the sealing segment when connecting the frame and the baffle, through the thread of the first sub-thread segment and the structure of the sealing glue layer set on the thread, the thread connection is connected and sealed, the sealing performance of the connection position is improved. The screw in the battery pack of the application improves the sealing performance of the connection position, reduces the risk of sealing failure, ensures the connection strength of the connection position, improves the situation that other foreign matters in the outside enter the battery pack through the connection position of the screw, reduces the probability of battery pack thermal runaway caused by foreign matters entering the battery pack, and is safer to use.

[0011] The application also provides an electric vehicle, comprising a chassis and a battery pack, wherein the battery pack is the battery pack described above, and the battery pack is fixedly connected to the chassis.

[0012] The electric vehicle of the application has the battery pack described above, and thus has the advantages of the battery pack described above, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0014] Figure 1 The structural schematic diagram of one angle of the box body of the battery pack provided by the embodiment of the application;

[0015] Figure 2 The structural schematic diagram of another angle of the box body of the battery pack provided by the embodiment of the application;

[0016] Figure 3 The structural schematic diagram of a third angle of the box body of the battery pack provided by the embodiment of the application;

[0017] Figure 4 The structural schematic diagram of the A part in the above; Figure 3 The local enlarged structural schematic diagram of the A part in the above;

[0018] Figure 5 The structural schematic diagram of the B-B position in the above; Figure 4 The sectional structural schematic diagram of the B-B position in the above;

[0019] Figure 6 The structural schematic diagram of the frame and the baffle connected by the screw provided by the embodiment of the application;

[0020] Figure 7 The structural schematic diagram of the frame and the baffle connected by the screw provided by the embodiment of the application;Figure 6 A cross-sectional view of the location of the central screw connection;

[0021] Figure 8 A schematic diagram of the structure of a screw at one angle provided in an embodiment of the present invention;

[0022] Figure 9 This is a schematic diagram of the screw from another angle provided in an embodiment of the present invention;

[0023] Figure 10 A schematic diagram of the screw at the third angle provided in an embodiment of the present invention;

[0024] Figure 11 for Figure 10 A cross-sectional view of the CC position in the diagram;

[0025] Figure 12 A schematic diagram of a frame and baffle connected by screws according to another embodiment of the present invention;

[0026] Figure 13 for Figure 12 A cross-sectional view of the location of the central screw connection;

[0027] Figure 14 A partial cross-sectional view of the positions of the first and second connecting holes provided in an embodiment of the present invention;

[0028] Figure 15 A cross-sectional view of the connection point between the frame and the baffle via screws, provided in an embodiment of the present invention;

[0029] Figure 16 A schematic diagram of a structure for setting a sealing gasket between the frame and the baffle provided in an embodiment of the present invention;

[0030] Figure 17 This is a schematic diagram of the structure of the box provided in an embodiment of the present invention.

[0031] in:

[0032] 1. Border,

[0033] 2. Baffle,

[0034] 3. Screws

[0035] 301. Nail head,

[0036] 3011, cavity; 3012, mounting slot.

[0037] 302, nail body,

[0038] 3021, attack segment, 30211, attack tip segment, 30212, attack body segment, 30213, cylindrical segment, 30214, connecting boundary line, 3022, thread segment, 30221, first sub-thread segment, 30222, second sub-thread segment,

[0039] 4, first connecting hole,

[0040] 5, second connecting hole,

[0041] 6, first boss,

[0042] 7, second boss,

[0043] 8, gasket,

[0044] 9, heat exchange channel,

[0045] 10, battery compartment,

[0046] 11, electrical compartment. DETAILED DESCRIPTION

[0047] The battery pack improves the sealing performance of the connecting position, ensures the connecting strength of the connecting position, reduces the probability of thermal runaway of the battery pack caused by foreign matter entering the battery pack, and is safer to use.

[0048] The application further discloses an electric vehicle.

[0049] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0050] Reference Figures 1 to 15 The battery pack of the application comprises a box body and a plurality of batteries placed in the box body, the box body comprises a frame 1 and a baffle 2, the frame 1 surrounds the periphery of the batteries, the baffle 2 and the frame 1 are oppositely arranged at the opening of at least one side of the frame 1, the frame 1 and the baffle 2 are fixedly connected through screws 3, and the screws 3 are at least partially embedded in the interiors of the frame 1 and the baffle 2. The screw 3 comprises a thread segment 3022, the thread segment 3022 comprises a first sub-thread segment 30221 and a second sub-thread segment 30222 which are connected, a sealing adhesive layer is arranged on the first sub-thread segment 30221 to form a sealing segment, and the sealing segment is at least partially connected to the connecting position of the frame 1 and the baffle 2. The length of the sealing segment is L, as shown in the figure. The friction coefficient of the sealing adhesive layer is K. The thickness of the connecting position of the frame 1 is D1, and the thickness of the connecting position of the baffle 2 is D2, as shown in the figure. Figure 9 Figure 7 ​The depth of the thread of the first sub-thread segment 30221 is H, as shown in the figure. Figure 11 The selection of the above parameters satisfies the formula: 0.06≤(L×K) / ((D1+D2)×H)≤2.3. The length L of the sealing segment is the total length of the sealing adhesive layer on the thread segment 3022, i.e. the total length of the first sub-thread segment 30221. Specifically, the value of the formula (L×K) / ((D1+D2)×H) can be any value in 0.06, 0.5, 1, 2.3, or a value between any two values.

[0051] The screw 3 can be a metal or non-metal material. When the screw 3 is a metal material, the screw 3 can be copper, aluminum, or stainless steel, etc. When the screw 3 is a non-metal material, the screw 3 can be polyethylene, polypropylene, or polyvinyl chloride, etc. The sealing adhesive layer is resistant to falling glue. The sealing adhesive layer can be, but is not limited to, silicone, polyurethane, acrylic, polysulfide, or polyamide, etc.

[0052] It is found that the additional sealing element arranged between the screw cap of the screw 3 and the baffle 2 has poor sealing compression effect and is easily affected by external force, leading to sealing failure, affecting the sealing effect between the battery box and the baffle 2, causing the inside and outside of the box to be connected, causing safety risks of the battery pack, heat exchange between the inside and outside, introduction of water vapor, impurities, etc. into the inside of the battery pack, easy short circuit and fire between the batteries, and thermal runaway in the inside of the battery pack, with gas and liquid directly sprayed to the outside of the box, causing safety hazards.

[0053] The battery pack of the present application realizes self-sealing of the screw 3 by arranging the sealing adhesive layer in part of the thread inside the thread segment 3022 of the screw 3, so that the sealing structure (the sealing adhesive layer) can be embedded inside the frame 1 and the baffle 2, realizing reliable sealing. However, the arrangement of the sealing adhesive layer on the screw 3 causes the screw 3 and the box to be in contact through the adhesive layer, and there is a risk in the connection strength of the screw 3, the frame 1 and the baffle 2, so when the sealing adhesive layer is arranged, the relationship between the length L of the sealing segment, the friction coefficient K of the sealing adhesive layer, the thickness D1 of the connection frame 1, the thickness D2 of the connection baffle 2 and the depth H of the sealing adhesive layer connecting thread should be considered, both to ensure that the sealing performance meets the requirements and to consider that the connection strength meets the relevant requirements. By controlling (L×K) / ((D1+D2)×H) in the above suitable range, the thread connection can be sealed by the structure of the thread and the sealing adhesive layer when the baffle 2 and the frame 1 of the battery pack are connected, the sealing performance is improved, the inside and outside of the battery pack are reliably isolated, and at the same time the connection strength of the baffle 2 and the frame 1 is guaranteed, avoiding the risk of deformation of the frame 1 or the baffle 2 under stress.

[0054] The formula range is too small, the LxK product ratio is too small, the sealant layer in the screw 3 is more likely to overflow, the glue layer is more likely to overflow from the thread, the length L of the sealing section is too small, and the sealing failure risk is increased; the formula range is too large, the (D1+D2)xH ratio is too small, the glue layer ratio is too large, or the baffle 2 and the frame 1 are too thin, the box structure strength is too low, the screwing strength between the screw 3 and the baffle 2 and the frame 1 is low, the subsequent baffle 2 and frame 1 connection failure risk is increased, and the fracture risk is large.

[0055] When the sum of the thickness D1 of the frame 1 connection position and the thickness D2 of the baffle 2 connection position is too large, the thickness of the screw to be connected position is too large, the processing is difficult, the sealing failure points are more, and the sealing performance is poor. When the sum of the thickness D1 of the frame 1 connection position and the thickness D2 of the baffle 2 connection position is too small, the thickness of the screw to be connected position is too small, although the processing is easy, the connection strength is weak, and since the thread connection length is short, the sealing performance is also affected. When the depth H of the thread of the first sub-thread section 30221, that is, the distance from the thread top to the thread bottom, is too large, the glue storage is more, the processing is difficult during self-drilling, and the connection depth of the thread is affected, the connection strength is affected, and when the depth H is too small, the glue storage is less, and the sealing performance is affected.

[0056] The box is used for containing a plurality of batteries and protecting the batteries from impact, and simultaneously performing sealing, waterproofing and other protection. The box includes a plurality of frames 1, including at least four frames, surrounding the outer periphery of the battery, and the upper and / or lower portions of the frame structure surrounded by the plurality of frames 1 are formed with openings, the baffle 2 is arranged opposite to and shielding the opening, and the baffle 2 can be used as a bottom plate or a box cover and is fixedly connected with the frame 1. Generally, two opposite frames 1 in the length direction of the box are provided with lifting openings for lifting the box, and the upper portion of the frame 1 further protrudes outward of the box to form a beam for bearing pressure. The outside of the box refers to the side of the box away from the battery. Two frames 1 in the width direction of the box are respectively used for mounting electrical connectors or water inlet and outlet openings, box explosion-proof valves and the like. The inside of the frame 1 can form a cavity for energy absorption and buffering, and the inside of the cavity can be provided with a sealant layer or an internal buffering material. The cavity can also be used as an exhaust chamber, and the frame 1 can be a solid plate. The cavity of the frame 1 can be formed by extrusion, bending or pressure casting. The baffle 2 can be formed with protrusions and recesses as a reinforcing structure. The baffle 2 and the frame 1 can be made of steel, aluminum or other metal or alloy materials.

[0057] The battery pack of the present application improves the sealing performance of the connecting position by setting the first sub-thread segment 30221 on the screw 3 as a sealing segment with a sealant layer, and sealing the threaded connection by the thread of the first sub-thread segment 30221 and the structure of the sealant layer on the thread when connecting the frame 1 and the baffle 2. At the same time, the ratio of formula (LxK) / ((D1+D2)xH) needs to be within a certain range to ensure the sealing performance while reducing the resistance during connection of the screw 3, and to ensure the connection strength of the connecting position. The screw 3 in the battery pack of the present application improves the sealing performance of the connecting position, reduces the risk of sealing failure, ensures the connection strength of the connecting position, improves the situation that other foreign matters from the outside enter the battery pack through the connecting position of the screw, reduces the probability of battery pack thermal runaway caused by foreign matters entering the battery pack, and is safer to use.

[0058] Further, the screw 3 includes a nail cap 301 and a nail body 302 connected together, the nail body 302 includes an attack segment 3021 and a threaded segment 3022, the attack segment 3021 is arranged at one end of the nail body 302 away from the nail cap 301, the threaded segment 3022 extends from a position close to the nail cap 301 to the attack segment 3021 and is arranged between the nail cap 301 and the attack segment 3021. After the attack segment 3021 passes through the frame 1 and the baffle 2, the sealing segment is at least partially located at the connecting position of the frame 1 and the baffle 2.

[0059] Wherein, the baffle 2 is arranged between the nail cap 301 and the frame 1, which improves the sealing effect of the whole box body and ensures that the battery box has enough space to accommodate the battery, thereby improving the overall space utilization rate of the battery pack.

[0060] In order to improve the sealing performance, the end face of the nail cap 301 close to the nail body 302 is provided with a concave cavity 3011, which is recessed away from the baffle 2, as shown in Figure 8 and Figure 11 The concave cavity 3011 is arranged around the end of the nail body 302 close to the nail cap 301, i.e. the concave cavity 3011 is arranged at the root of the nail body 302 and around the root of the nail body 302. The concave cavity 3011 can be a continuous annular groove or a plurality of single grooves arranged around the nail body 302. By arranging the concave cavity 3011, when the screw 3 is fixedly connected to the baffle 2 and the frame 1, the sealant layer overflows from the thread, the concave cavity 3011 accommodates the glue layer or the protruding structure formed by the baffle 2 and the frame 1 overflowing due to heat, avoiding poor contact between the nail cap 301 and the baffle 2 caused by the overflowing glue layer or the protruding structure formed by the baffle 2 and the frame 1 overflowing due to heat, and reducing the risk of sealing failure caused by the overflowing glue layer or the protruding structure formed by the baffle 2 and the frame 1 overflowing due to heat. Preferably, the concave cavity 3011 is Figure 8The sealing segment of the screw 3 is connected to the continuous annular groove in the grommet 2. In order to improve the sealing performance, the sealing segment extends into the cavity 3011.

[0061] In order to ensure the accommodation space, referring to Figure 11 As shown in the figure, the depth d of the cavity 3011 is 1mm~3mm; and / or, the size of the cavity 3011 along the vertical direction of the screw 3 is 8~15mm, i.e. the width w of the cavity 3011 along the radial direction of the screw is 8~15mm. Specifically, the value of the depth d of the cavity 3011 can be any value among 1mm, 2mm, 3mm or between any two values, and the value of the width w of the cavity 3011 can be any value among 8mm, 12mm, 15mm or between any two values. If the depth d or the width w of the cavity 3011 is too small, the glue layer will overflow, or the protruding structure formed by the heat of the baffle 2 and the frame 1 will overflow, resulting in the inclination of the nail cap 301 or the poor contact between the nail cap 301 and the baffle 2, which will cause the sealing failure, the failure of the internal structure of the battery box, and the great safety risk of the thermal runaway of the battery box. If the depth d or the width w of the cavity 3011 is too large, the structural strength of the nail cap 301 is weak, and the connection strength of the box is weak.

[0062] In order to facilitate the connection of the screw 3 to the frame 1 and the baffle 2, the first connecting hole 4 for the screw 3 to pass through is arranged on the baffle 2, and the second connecting hole 5 for the screw 3 to pass through is arranged on the frame 1, as shown in the figure. Figure 14 The sealing segment of the screw 3 is connected to the first connecting hole 4 and / or the second connecting hole 5. In an embodiment, in order to improve the sealing performance of the connection position of the threaded segment 3022, the sealing segment of the screw 3 is connected to the positions of the first connecting hole 4 and the second connecting hole 5, i.e. the first sub-threaded segment 30221 is connected to the positions of the first connecting hole 4 and the second connecting hole 5, and the sum of the hole heights of the first connecting hole 4 and the second connecting hole 5 is less than or equal to the thread length of the first sub-threaded segment 30221, so that the threaded segment with the glue layer is connected into the first connecting hole 4 and the second connecting hole 5. In other embodiments, the sealing segment of the screw 3 is connected to at least all or part of the positions of the first connecting hole 4 or the second connecting hole 5.

[0063] In order to avoid the dust or water entering the first connecting hole 4 on the baffle 2, the end surface of the nail cap 301 close to the nail body 302 abuts against the baffle 2, as shown in the figure. Figure 6 Figure 7 That is, the end surface of the nail cap 301 close to the nail body 302 is pressed against the surface of the baffle 2, which reduces the risk of foreign matter entering the first connecting hole 4 through the gap between the baffle 2 and the end surface of the nail cap 301.

[0064] ​Further, corresponding to the position of the recess 3011, the baffle 2 is provided with a first boss 6, the first boss 6 is provided away from the end of the frame 1 around the first connecting hole 4, the first boss 6 is correspondingly provided with the recess 3011, the corresponding provided here refers to the position corresponding provided, the first boss 6 is provided in the recess 3011. In order to avoid the influence of the first boss 6 on the connection of the screw 3, the recess 3011 is a continuous annular groove structure. As shown in Figure 15 , the first boss 6 extends into the recess 3011, and a sealing structure is formed on the end face of the nail cap 301 close to the baffle 2, further improving the sealing performance of this position. The thickness of the first boss 6 in the radial direction is less than the size of the recess 3011 in the radial direction (the width of the recess 3011), so that the first boss 6 can extend into the recess 3011. The end face of the nail cap 301 away from the nail body 302 is provided with a clamping groove 3012, the groove type of the clamping groove 3012 is correspondingly provided with a tool used when the screw 3 is self-drilled, as Figure 10 , a schematic diagram of a groove type for the clamping groove 3012, in other embodiments, it can also be other groove types used with tools, which are not limited here.

[0065] Specifically, the length L of the sealing section ranges from 3mm to 10mm. The length L of the sealing section can be any value among 3mm, 5mm, 8mm, 10mm, or a value between any two values. The friction coefficient K of the sealing layer ranges from 0.1 to 0.25. The friction coefficient K of the sealing layer can be any value among 0.1, 0.15, 0.25, or a value between any two values. The thickness D1 of the frame 1 connection position ranges from 1.2mm to 3mm. The thickness D1 can be any value among 1.2mm, 2mm, 3mm, or a value between any two values. The thickness D2 of the baffle 2 connection position ranges from 0.8mm to 2mm. The thickness D2 can be any value among 0.8mm, 1.5mm, 2mm, or a value between any two values. The depth H of the thread of the first sub-thread section 30221 ranges from 0.5mm to 1.2mm. The depth H of the thread of the first sub-thread section 30221 can be any value among 0.5mm, 0.8mm, 1.2mm, or a value between any two values. When the length L of the sealing section is too small, the sealing effect of the connection position is poor. When the length L of the sealing section is too large, the resistance is large when the screw 3 drills a hole, so the length range of the parameter L is limited to ensure the sealing performance of the screw while reducing the resistance when drilling a hole. When the friction coefficient K of the sealing layer is too large, although the sealing layer is not easy to fall off and can ensure the sealing requirement, the excess glue is not easy to be taken away when the thread is drilled, which can cause the thread depth of the connection position of the first sub-thread section 30221 and the connected part to be insufficient, affecting the connection strength. When the friction coefficient K of the sealing layer is too small, the sealing layer is easy to fall off when the screw is drilled, affecting the sealing performance, so the range of the friction coefficient K of the sealing layer is limited to ensure the connection strength and the sealing performance of the screw. When the sum of the thickness D1 of the frame 1 connection position and the thickness D2 of the baffle 2 connection position is too large, the thickness of the screw connection position is too large, which is difficult to process, and the more sealing failure points, the poorer the sealing performance. When the sum of the thickness D1 of the frame 1 connection position and the thickness D2 of the baffle 2 connection position is too small, the thickness of the screw connection position is too small, which is easy to process, but the connection strength is weak, and the short thread connection length also affects the sealing performance. When the depth H of the thread of the first sub-thread section 30221, i.e., the distance from the thread top to the thread bottom, is too large, there is too much glue, which is difficult to process when drilling, and affects the connection depth of the thread and the connection strength. When the depth H is too small, there is too little glue, which affects the sealing performance.

[0066] In an embodiment, as Figure 6 and Figure 7As shown, the baffle 2 is a single-layer supporting bottom plate. The material of the baffle 2 can be aluminum alloy, high-strength steel, carbon fiber composite material, glass fiber composite material, or honeycomb sandwich structure material, etc. In another embodiment, the baffle 2 is a heat exchange plate for heat exchange with the bottom of the battery, and the heat exchange plate is in thermal contact with the battery. When the baffle 2 is a heat exchange plate, the range of the formula (L x K) / ((D1 + D2) x H) is 0.08-2. Specifically, the value of the formula (L x K) / ((D1 + D2) x H) can be any value in 0.08, 1.5, 2, or a value between any two values. The heat exchange plate is used to heat or cool the battery, to adjust the temperature of the battery, and is internally provided with a heat exchange channel 9, such as Figure 4 As shown, the heat exchange medium can be introduced into the heat exchange channel 9, and the heat exchange medium includes cooling water, cooling liquid, gas, or phase change material, etc.

[0067] Specifically, the heat exchange plate includes a first cold plate and a second cold plate connected together, as shown. Figures 12 to 15 The first connecting hole 4 is provided on the first cold plate, the first cold plate is provided on one side of the second cold plate close to the frame 1, the second cold plate is provided with a clearance hole with a diameter larger than the first connecting hole 4 to facilitate the connection of the screw 3, and a position is reserved for the first boss 6. The first cold plate and the second cold plate are stacked up and down to form a heat exchange channel 9. The screw 3 is connected to the position of the heat exchange plate where the heat exchange channel 9 is not provided. The heat exchange channel 9 can include a plurality of single flow channels arranged at intervals.

[0068] In order to ensure the safety performance of the heat exchange channel 9 and avoid affecting the heat exchange channel 9 when the screw 3 is connected, the distance L1 between the end of the heat exchange channel 9 and the frame 1 is 7-60 mm, as shown. Figure 4 Specifically, the distance L1 between the end of the heat exchange channel 9 and the frame 1 can be any value in 7 mm, 20 mm, 40 mm, 60 mm, or a value between any two values. If the distance between the end of the heat exchange channel 9 and the frame 1 is too close, the heat exchange plate will be deformed greatly when the screw 3 fastens the baffle 2 and the frame 1, and there is a risk of structural failure of the heat exchange channel 9; if the distance is too far, the heat exchange channel 9 will be difficult to efficiently heat the battery, and the battery heat exchange area will be small.

[0069] In order to improve the sealing performance of the contact surface between the frame 1 and the baffle 2, a sealing gasket 8 is further provided between the frame 1 and the baffle 2, as shown. Figure 16 The material of the sealing gasket 8 is EPDM, fluorine rubber, silicone rubber, foamed silicone, or acrylic foam tape, etc.

[0070] Specifically, the sealing gasket 8 is provided on the side of the screw 3 close to the battery, and the distance L2 between the edge of the sealing gasket 8 and the screw 3 is 3-25 mm, as shown. Figure 16The distance L2 between the edge of the sealing gasket 8 and the screw 3 can be any value in 3mm, 10mm, 18mm, 25mm, or any value between any two values. If the distance L2 between the edge of the sealing gasket 8 and the screw 3 is too small, the sealing gasket 8 is easy to be burnt by the high temperature generated when the screw 3 is self-drilled. If the distance L2 between the edge of the sealing gasket 8 and the screw 3 is too large, the effective width of the sealing gasket 8 between the frame 1 and the baffle 2 is small, and the sealing performance between the contact surface of the frame 1 and the baffle 2 is affected.

[0071] In an embodiment, the starting end of the sealing section is in contact with the end surface of the nail cap 301. In this embodiment, the sealing section is arranged starting from the end surface of the nail cap 301. The sealing performance of this structure is better, but the position where the nail cap 301 is connected with the nail body 302 is not convenient for coating the sealing glue layer. In another embodiment, the threaded section 3022 further comprises a third sub-threaded section (not shown in the figure). The third sub-threaded section, the first sub-threaded section 30221 and the second sub-threaded section 30222 are arranged in sequence from the nail cap 301 to the tapping section 3021. The sealing section is arranged between the third sub-threaded section and the nail cap 301. In this embodiment, the first sub-threaded section 30221 is spaced from the nail cap 301 by the third sub-threaded section.

[0072] In order to improve the efficiency of connection, in an embodiment, the distance between the distal end of the sealing glue layer and the nail cap 301 is a first distance, and the thickness of the position where the frame 1 and the baffle 2 are connected with the screw 3 is a second distance. The first distance is smaller than the second distance. The distal end of the sealing glue layer here refers to the end of the sealing glue layer away from the nail cap 301. The first distance is smaller than the second distance, and when the screw 3 is connected with the baffle 2 and the frame 1, the sealing glue layer does not expose the frame 1. The sealing glue layer can be flush with the end of the frame 1 away from the baffle 2, or can be lower than the end of the frame 1 away from the baffle 2. In this embodiment, the range of the formula (L×K) / ( (D1+D2)×H) is 0.09~2.3.

[0073] In order to improve the sealing performance of the connection position, in another embodiment, the distance between the distal end of the sealant layer and the nail cap 301 is a first distance, and the total thickness of the position where the frame 1 and the baffle 2 are connected by the screw 3 is a second distance, and the first distance is greater than the second distance. The distal end of the sealant layer here refers to the end of the sealant layer away from the nail cap 301. When the screw 3 connects the baffle 2 and the frame 1, the height of the sealant layer exceeds the end of the frame 1 away from the baffle 2. In this embodiment, the formula (LxK) / ((D1+D2)xH) is in the range of 0.06-2. In order to reduce the resistance during connection of the screw 3 and improve the connection efficiency, the difference between the first distance and the second distance is 1-5 mm, that is, the height of the end of the frame 1 away from the baffle 2 is controlled within the above range. The greater the difference between the first distance and the second distance, the greater the resistance during connection of the screw 3, and the lower the connection efficiency. The smaller the difference between the first distance and the second distance, the more difficult it is to ensure the sealing performance of the connection position.

[0074] In order to facilitate the connection of the screw 3 to the frame 1 and the baffle 2, as shown in Figure 12 and Figure 13 , the frame 1 is a hollow plate body with a cavity, and a plurality of cavities are arranged in the frame 1. When the screw 3 is threadedly connected from the baffle 2 to the frame 1, the screw 3 can be self-drilling, and the frame edge can be quickly drilled, thereby improving the connection efficiency. At the same time, the frame 1 is arranged as a hollow plate body with a cavity, which can reduce the weight of the box body, has good heat and sound insulation performance, and reduces the influence of the temperature of the external environment on the battery.

[0075] Specifically, the attack section 3021 is drilled into the frame 1 from the baffle 2, and the attack section 3021 extends into the cavity. In order to improve the performance of the threaded connection, the attack section 3021 includes an attack tip section 30211 and an attack body section 30212, as shown in Figure 9 and Figure 11 , the outer surface of the attack tip section 30211 is a first conical surface, and the attack body section 30212 is provided with a second conical surface close to the attack tip section 30211, and the taper angle of the first conical surface is smaller than the taper angle of the second conical surface, so as to form a connection boundary line 30214 at the connection position of the attack tip section 30211 and the attack body section 30212, so that the attack section 3021 forms two conical surfaces with different taper angles, so as to facilitate the constant force drilling and reaming of the screw 3, and avoid the need to increase the drilling force when only one conical surface is arranged on the attack section 3021 during drilling. The end of the attack body section 30212 away from the attack tip section 30211 is connected to the threaded section 3022 through a cylindrical section 30213.

[0076] Further, the total thickness of the position where the frame 1 and the baffle 2 are connected by the screw 3 is less than the length of the first thread segment 30221, so that the attack segment 3021 is completely located in the cavity of the frame 1, so that the sealing segment is completely connected in the first connecting hole 4 and the second connecting hole 5, so as to improve the sealing property of the connection. Wherein, the distance L3 between the top end of the attack segment 3021 and the corresponding surface of the cavity (the top surface of the cavity corresponding to the attack tip segment 30211) is 3-25mm, referring to Figure 13 If the distance L3 between the top end of the attack segment 3021 and the corresponding surface of the cavity is too large, the connection reliability of the screw 3 cannot be guaranteed, and if the distance is too small, the top surface of the cavity is easily damaged. The distance L3 can be any value among 3mm, 10mm, 18mm, 25mm or a value between any two values.

[0077] In order to improve the connection reliability, the baffle 2 is connected by a plurality of screws 3 at each edge where the screw 3 is arranged, and the plurality of screws 3 are evenly arranged along the edge of the baffle 2, and the interval distance L4 between adjacent screws 3 is 50-140mm, as shown in Figure 5 If the interval distance L4 between adjacent screws 3 is too small, the strength of the baffle 2 and the frame 1 will be affected due to too many connecting holes, and if the interval distance is too large, the connection reliability will be reduced, and the sealing property of the connection will also be reduced. Specifically, the screw 3 is arranged on two long edges of the baffle 2. The interval distance L4 between adjacent screws 3 can be any value among 50mm, 80mm, 110mm, 140mm or a value between any two values. Wherein, the interval distance L5 between the screw cap 301 and the edge of the baffle 2 is 8-30mm, as shown in Figure 6 to ensure the reliable connection of the screw 3 and the baffle 2. The interval distance L5 between the screw cap 301 and the edge of the baffle 2 can be any value among 8mm, 15mm, 20mm, 30mm or a value between any two values. If the interval distance L5 is too large, the screw 3 cannot guarantee the reliable connection with the frame 1, and if the interval distance is too small, the screw 3 cannot guarantee the reliable connection with the baffle 2.

[0078] In order to better seal the end of the second connecting hole 5 away from the first connecting hole 4, the frame 1 is provided with a second boss 7, the second boss 7 protrudes from the frame 1 and is arranged at the outer periphery of the screw 3, as shown in Figure 15The second boss 7 is arranged at the end of the second connecting hole 5 away from the baffle 2. The threads of the sealing section of the screw 3 are at least partially connected to the position of the second boss 7, so as to form a seal of the second boss 7 and the threads. In an embodiment, the height of the end of the sealing adhesive layer away from the baffle 2 is lower than the height of the second boss 7. In another embodiment, the height of the end of the sealing adhesive layer away from the baffle 2 is higher than the second boss 7, and the distance L6 between the end of the sealing adhesive layer and the second boss 7 is 1-6 mm. The distance L6 between the end of the sealing adhesive layer and the second boss 7 can be any value in 1 mm, 3 mm, 6 mm, or a value between any two values. If the distance L6 is too large, the connection resistance of the screw 3 will be large, which is not convenient for connection. If the distance L6 is too small, the connection sealing performance of the screw 3 will be poor.

[0079] The battery is placed on the baffle 2, and the ratio of the area of the battery to the total area of the baffle 2 is 75%-95%. The box body includes a battery compartment 10 for placing the battery and an electrical compartment 11, as shown in Figure 17 The battery occupies an area ratio of the battery compartment 10 to the entire baffle 2. In this embodiment, the formula (LxK) / ((D1+D2)xH) is in the range of 0.09-1.9. When the ratio of the area of the battery to the total area of the baffle 2 is large, the weight of the battery is large, and a large weight is pressed on the baffle 2, which requires higher connection reliability of the connection position of the frame 1 and the baffle 2, and more screws 3 need to be arranged. When the ratio of the area of the battery to the total area of the baffle 2 is small, the weight of the battery is small, and a small weight is pressed on the baffle 2, which requires higher connection reliability of the connection position of the frame 1 and the baffle 2.

[0080] In order to ensure the connection reliability, the ratio of the height of the threaded section 3022 to the height of the screw 3 is 60%-80%. If the ratio of the height of the threaded section 3022 to the height of the screw 3 is too small, the connection strength between the screw 3 and the frame 1 and the baffle 2 is weak, and the screw 3 is difficult to quickly pass through the baffle 2 and the frame 1. If the ratio of the height of the threaded section 3022 to the height of the screw 3 is too large, since the screw 3 has a self-drilling effect when connected, the threaded length is long, the hole diameter size of the hole of the baffle 2 and the frame 1 for connecting the screw 3 is large, which easily causes the problem of invalidation of the sealing effect.

[0081] To ensure a good seal while reducing connection resistance, the thickness of the sealant layer is 30% to 50% of the thread depth of the threaded section 3022. If the thickness of the sealant layer is too small (i.e., the layer is too thin), the sealant layer will be weak, and there is a risk of seal failure inside the battery pack. If the thickness of the sealant layer is too large (i.e., the layer is too thick), the sealant layer will easily overflow from the threads of the screw 3, causing the screw head 301 to warp and deform, and the connection strength between the screw 3, the frame 1, and the baffle 2 will be weak.

[0082] Friction coefficient K test method: Referring to ASTM D2714 (General Guide for Testing Coatings for Friction), fretting friction tests were conducted on sealants of different materials and properties. Specifically, a sealant with the same material parameters as the sample screw was coated onto the substrate, with the same coating thickness and process as the screw. After curing, the cross-section was polished. A fretting wear tester was used, with a φ3mm hard steel ball (GCr15, hardness 60 HRC) as the friction pair. The normal load was 15 N to simulate the coating under pressure, the sliding amplitude was 50μm, the frequency was 3 Hz, and the number of cycles was 1000. The equipment measured the friction force (Ft) in real time and calculated the instantaneous friction coefficient: μ = Ft / Fn. Initial fluctuation data were discarded, and the average steady-state friction coefficient was output to obtain the friction coefficient K of multiple sample sealants.

[0083] Preparation of test sample battery packs: A batch of battery pack frame boxes with dimensions of 1010mm×1030mm×110mm and matching base plates were selected. The thickness of the connection between the battery pack frame 1 and the base plate is different, and the thickness of the connection between the base plates is also different. The screws 3 are flow drill screws. The thread length, friction coefficient of the sealant, and thread depth of the screws are all different. For specific parameters, please refer to the table in the example. Except for the above-mentioned parameter differences, the other performance and structural parameters of the battery pack frame, base plate, and screws are the same.

[0084] The battery pack housing frame 1, base plate, and screws 3 are selected and assembled using the same process. The battery pack housing frame 1 and base plate are fixedly connected by screws 3. The same sealing gaskets 8 are set between the battery pack housing frame 1 and base plate. The installation distance between two adjacent screws 3 is 70mm, thus obtaining the battery pack structure.

[0085] Using individual cells from the same batch, with identical performance and structural parameters, and following the conventional battery pack assembly process, each battery pack contains 100 individual cells measuring 26mm × 148mm × 100mm. These cells are bonded to the base plate with structural adhesive, and the upper opening of the battery pack is sealed with the same cover to prepare the sample battery pack.

[0086] Battery pack performance test method:

[0087] Performance 1: battery pack air tightness test:

[0088] First clean the appearance of the battery pack, check for no mechanical damage, ensure that the inflation port is unobstructed, install the sealing test tool connected with the inflation port of the battery pack on the air tightness detector, connect the air pipe, check the sealing of the air path system, start the air tightness detector. Set the inflation pressure to 3.65 kPa ± 0.15 kPa, the inflation time to 480 s, start the detection program, inflate the closed cavity, monitor the pressure change curve in real time, after the inflation reaches the set pressure, enter the balance time of 60 s, balance the internal pressure of the battery pack with the cavity pressure, the detector continues to monitor the pressure change, after the balance time is over, keep the pressure at 3.65 kPa ± 0.15 kPa, enter the detection time of 60 s, the detector calculates the leakage, when the leakage is greater than 10 mL / min, it is judged to be unqualified, there is sealing failure at the connection of screw 3.

[0089] Performance 2: loosening torque test

[0090] Use the torque wrench to pre-tighten the screw 3 according to the design torque of 13 Nm, record the initial torque value, fix the battery pack on the vibration table, set the vibration frequency to 30 Hz and the vibration amplitude to 1 mm, and continuously vibrate for 30 minutes to simulate the vibration working condition in the process of vehicle driving. After vibration, select 10 screws 3 on one battery pack to test the loosening torque, slowly apply torque in the opposite direction with the torque wrench to loosen the screw 3, read the instantaneous torque value when the screw 3 is loosened, which is the loosening torque value, record 10 values, as long as one of the loosening torques is less than 7.8 Nm, it is judged to be unqualified, the screw 3 installation part has problems such as loosening and reduced connection strength after vibration.

[0091] The above battery pack is used for testing, and the data obtained are shown in Examples 1 to 17 in the following table. In Examples 1 to 17, the performance parameters of the tested samples meet: 0.06≤(L×K) / ((D1+D2)×H)≤2.3, in the battery pack air tightness test, the sealing of the screw connection of the sample battery pack is good, there is no sealing failure point, and the battery pack air tightness detection meets the design requirements. In the loosening torque test, the battery pack simulates the test scene, and the loosening torque of the screw on the battery pack is tested after the vibration test. The test shows that the loosening torque of the screw at the connection of the battery pack in the above examples meets the design requirements, proving that the connection strength at the connection still meets after impact and vibration.

[0092]

[0093] In the embodiments 13 to 17, the performance parameters of the sample battery pack selected for testing meet the condition: 0.06≤(L×K) / ((D1+D2)×H)≤2.3, but when each structural parameter is selected, there is also a certain influence on the performance. In the embodiments 13 and 16, the length L of the sealing section is selected to be small, which weakens the sealing performance of the screw connection. In the embodiments 14 and 17, the length L of the sealing section is selected to be large, which improves the sealing performance but increases the resistance during assembly. In the two embodiments, the friction coefficient K of the sealing adhesive layer is selected to be small, which causes the adhesive layer to fall off during assembly, affecting the sealing performance after assembly. In the embodiments 15 and 16, the friction coefficient K of the sealing adhesive layer is selected to be large, which also causes a large resistance during assembly. In the embodiments 13 and 16, the thickness D1 of the frame 1 at the connection is selected to be large, which causes the screw to be drilled to a large size, resulting in a large size of the connection and an increased risk of sealing failure. In the embodiments 15 and 17, the thickness D1 of the frame 1 at the connection is selected to be small, which weakens the connection and reduces the connection strength. Similarly, in the embodiments 14 and 17, the thickness D2 of the baffle 2 is selected to be large, which also increases the risk of sealing failure. In the embodiments 13 and 16, the thickness D2 of the baffle 2 as the bottom plate is selected to be small, which reduces the connection strength. In the embodiments 14 and 17, the screw thread depth is selected to be small, the amount of sealing adhesive is small, and the sealing performance of the connection is weakened. In the embodiments 15 and 16, the screw thread depth is selected to be large, the amount of sealing adhesive is large, and the resistance during assembly is increased, which affects the connection strength of the thread at the connection.

[0094] In the comparative examples 1 to 3, (L×K) / ((D1+D2)×H)≤0.06, the loosening torque test meets the design requirements, but the battery pack air tightness test shows that the connection sealing fails and the air tightness does not meet the design requirements. In the comparative examples 4 to 6, 2.3≤(L×K) / ((D1+D2)×H), the battery pack air tightness test meets the design requirements and there is no risk of sealing failure, but after the vibration test, the loosening torque of the FDS nail does not meet the design requirements and the connection strength is weak.

[0095] The battery pack of the present application uses screws 3 to connect the frame 1 and the baffle 2, which has good connection sealing performance, can effectively reduce the entry of foreign matter into the box of the battery pack, effectively protect the batteries in the box, and reduce the probability of battery thermal runaway caused by foreign matter entering the battery cavity through the screw connection position.

[0096] The present application also provides an electric vehicle comprising a chassis and a battery pack, wherein the battery pack is the above-mentioned battery pack, and the battery pack is fixedly connected to the chassis.

[0097] The battery pack comprises a box body, and the box body comprises a baffle 2 arranged at one end of the box body away from the base plate.

[0098] In the description of the present application, it should be understood that the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0099] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0100] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery pack, characterized by, The battery pack comprises a box body and a plurality of batteries placed in the box body, the box body comprises a frame and a baffle, the frame surrounds the periphery of the batteries, the baffle and at least one side opening of the frame are oppositely arranged, the frame and the baffle are fixedly connected by a screw, the screw is at least partially embedded in the interior of the frame and the baffle, the screw comprises a threaded segment, the threaded segment comprises a first sub-threaded segment and a second sub-threaded segment arranged in connection, a sealing adhesive layer is arranged on the first sub-threaded segment to form a sealing segment, and the sealing segment is at least partially connected to the connection position of the frame and the baffle. A second boss is arranged on the frame, the second boss protrudes from the frame and is arranged on the periphery of the screw, the threads of the sealing segment of the screw are at least partially connected to the second boss, and the height of the end of the sealing adhesive layer away from the baffle is lower than that of the second boss.

2. The battery pack of claim 1, wherein, The height of the end of the sealing adhesive layer away from the baffle is higher than that of the second boss, and the distance between the end of the sealing adhesive layer and the second boss is 1-6 mm.

3. The battery pack of claim 1, wherein, The screw comprises a nail cap and a nail body connected together, the nail body comprises an attack segment and the threaded segment, the attack segment is arranged at the end of the nail body away from the nail cap, and the threaded segment is arranged between the nail cap and the attack segment; and the sealing segment is at least partially located at the connection position of the frame and the baffle.

4. The battery pack of claim 3, wherein, The baffle is arranged between the nail cap and the frame.

5. The battery pack of claim 3, wherein, The end face of the nail cap close to the nail body is provided with a concave cavity, and the concave cavity is recessed away from the baffle.

6. The battery pack of claim 5, wherein, The concave cavity is a continuous annular groove, and the sealing segment extends into the concave cavity.

7. The battery pack of claim 5, wherein, The size of the opening end of the concave cavity is greater than that of the bottom of the concave cavity.

8. The battery pack of claim 5, wherein, The depth of the concave cavity is 1-3 mm; and / or, the size of the concave cavity along the vertical screw extension direction is 8-15 mm.

9. The battery pack of claim 5, wherein, The baffle is provided with a first connecting hole for the screw to pass through, and the frame is provided with a second connecting hole for the screw to pass through, and the sealing segment of the screw is connected to the first connecting hole and / or the second connecting hole.

10. The battery pack of claim 9, wherein, The baffle is provided with a first boss, the first boss is arranged away from the end of the frame around the first connecting hole, the first boss is arranged corresponding to the concave cavity, and the first boss is at least partially arranged in the concave cavity.

11. The battery pack of any one of claims 1-10, wherein, The screw is a flow drill screw or a rivet screw, the screw is made of metal or non-metal material, and the sealing adhesive layer is resistant to falling glue.

12. An electric vehicle comprising a chassis and a battery pack, characterized in that, The battery pack is the battery pack of any one of claims 1-11, and the battery pack is fixedly connected to the bottom disc.

13. The electric vehicle of claim 12, wherein, The battery pack comprises a box body, and the box body comprises a baffle arranged at the end of the box body away from the bottom disc.

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