Lower box of battery box, battery pack and electric vehicle

Abstract

The present invention discloses a lower box body of a battery box, a battery pack and an electric vehicle. The lower box body of the battery box is used to form a battery pack. The lower box body is made of a non-metal composite material. The lower box body has a bottom plate and side walls arranged around the edge of the bottom plate. A reinforcing structure is arranged on the outer peripheral surface of the side wall. The side wall forms the reinforcing structure by extending outward. The reinforcing structure is provided with a plurality of mounting structures for installing a connecting mechanism. The lower box body is made of a non-metal composite material. Compared with a lower box body made of metal, it has a better thermal insulation effect, is more suitable for use in cold areas, and is lighter in weight. The lower box body forms a reinforcing structure by extending the side wall outward to enhance the strength of the side wall, facilitates the arrangement of the mounting structure on the reinforcing structure, and further facilitates the installation of the connecting mechanism for the connection of battery pack accessories (such as a quick-change unit or a battery pack fixing unit).

Description

[0001] This application claims the priority of Chinese patent application No. 202111567173.8, filed on December 20, 2021. This application cites the entire text of the above Chinese patent application. Technical Field

[0002] The present invention relates to the field of battery replacement of electric vehicles, and in particular to a lower box body of a battery box, a battery pack and an electric vehicle. Background Art

[0003] Electric vehicles have the advantages of zero emissions, low noise, and economical operation and maintenance, and are becoming more and more popular among users. The energy used by electric vehicles is the electricity provided by the battery packs on board. Electric vehicles need to be charged after the electricity is used up. The battery packs of electric vehicles are generally divided into fixed and replaceable types. Among them, fixed battery packs are generally fixed on the vehicle, and the vehicle is directly used as the charging object when charging. The replaceable battery packs are generally fixed on the bracket of the vehicle through a movable installation method. The battery pack can be removed for replacement or charging operations separately. After the replaced battery pack is charged, it is installed on the vehicle.

[0004] The connection mechanism of the existing battery box is set on the shell of the battery box, which causes the battery box shell to be in a state of great stress. After long-term use, it is easy to cause the battery box shell to deform and the connection is unreliable. In addition, the shell of the existing battery pack is made of metal, resulting in poor thermal insulation effect of the battery pack, and the temperature of the battery pack is easy to change with the ambient temperature. Especially when the battery pack is used in cold areas, when the ambient temperature is low, the temperature of the battery cells inside the battery pack drops quickly, and the battery pack performance is significantly reduced. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the battery box shell is relatively weak and it is not convenient to set a connection structure, and to provide a lower box body of a battery box, a battery pack and an electric vehicle.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] A lower box body of a battery box is used to form a battery pack. The lower box body is made of a non-metallic composite material. The lower box body has a bottom plate and side walls arranged around the edge of the bottom plate. A reinforcing structure is arranged on the outer peripheral surface of the side wall. The side wall is formed by extending outward to form the reinforcing structure. The reinforcing structure is provided with a plurality of mounting structures for installing a connecting mechanism.

[0008] In this solution, the lower box is made of non-metallic composite material, which has better thermal insulation effect than metal lower boxes, is more suitable for use in cold regions, and is lighter. The lower box extends the side wall outward to form a reinforcement structure to enhance the strength of the side wall, making it easier to set a mounting structure on the reinforcement structure, and further facilitating the installation of a connecting mechanism for connecting battery pack accessories (such as a quick-change unit or a battery pack fixing unit).

[0009] Preferably, the reinforcement structure includes a first reinforcement portion, a second reinforcement portion and a plurality of external reinforcement ribs, the first reinforcement portion and the second reinforcement portion are arranged one above and one below around the side wall, and the plurality of external reinforcement ribs are arranged between the first reinforcement portion and the second reinforcement portion along the circumferential direction of the side wall.

[0010] In this solution, the first reinforcement part and the second reinforcement part strengthen the strength of the side wall of the lower box body in the circumferential direction, and the external reinforcement rib is arranged between the first reinforcement part and the second reinforcement part to strengthen the strength of the side wall in the vertical direction. The above structural form is adopted to enhance the strength of the side wall of the lower box body in the circumferential and vertical directions, and is conducive to the lightweight of the lower box body structure.

[0011] Preferably, a plurality of the external reinforcing ribs separate the space between the first reinforcing portion and the second reinforcing portion into a plurality of regions, and the regions are filled with lightweight thermal insulation material.

[0012] In this solution, the space formed in the reinforced structure is filled with lightweight insulation materials, which helps to improve the insulation performance of the lower box. Lightweight insulation materials include, but are not limited to: polymer foam materials, aerogel felt, etc. Polymer foam materials refer to microporous materials based on polymers (plastics, rubbers, elastomers or natural polymer materials) with countless bubbles inside. Typical polymer foam materials include polyurethane foam, polystyrene foam, etc. Preferably, the polymer foam material is polyurethane foam.

[0013] Preferably, the inner surface of the bottom plate is provided with internal reinforcing ribs arranged at intervals or in a staggered manner;

[0014] Alternatively, the inner surface of the bottom plate and the inner surface of the side wall are provided with internal reinforcing ribs arranged at intervals or in a staggered manner.

[0015] In this solution, the internal reinforcing ribs can be arranged only on the inner surface of the bottom plate, or can be arranged on the inner surface of the bottom plate and the inner surface of the side wall at the same time. The above arrangement can realize the reinforcement of the bottom plate (and the side wall) of the lower box. The internal reinforcing ribs inside the lower box and the peripheral reinforcing structure are used to improve the overall strength of the lower box, and it is also convenient to form a cavity between the internal reinforcing ribs and / or in the frame of the reinforcing structure, and a heat-insulating material can be placed in the cavity to improve the heat-insulating effect of the lower box.

[0016] Preferably, at least a portion of the external reinforcement ribs are arranged at positions corresponding to the internal reinforcement ribs.

[0017] In this solution, corresponding reinforcement structures are formed inside and outside the lower box body to improve the overall strength of the lower box body.

[0018] Preferably, the mounting structure includes a receiving hole and a placement groove arranged in the reinforcement structure, the receiving hole is communicated with the placement groove, and the receiving hole has one end leading to the outer surface of the reinforcement structure; the receiving hole and the placement groove are respectively used to install a connecting member and a locking member constituting the connecting mechanism, so that the connecting member is connected to the locking member located in the placement groove through the receiving hole.

[0019] In this solution, the above-mentioned structural form is adopted to facilitate the installation of the locking member and the connecting member.

[0020] Preferably, the number of the accommodating holes is several, and each of the accommodating holes has an end leading to the outer surface of the side portion of the reinforcing structure;

[0021] Alternatively, the number of the accommodating holes is several, a portion of the accommodating holes has an end leading to the side outer surface of the reinforcing structure, and the remaining portion of the accommodating holes has an end leading to the bottom outer surface of the reinforcing structure.

[0022] In the present solution, the above two types of mounting structures, by cooperating with the connecting parts and the locking parts, can realize the connection of the quick-change unit or the battery pack fixing unit from the side, or realize the connection of the quick-change unit or the battery pack fixing unit from the side and the bottom. When the quick-change unit or the battery pack fixing unit is connected to the battery box through the structural parts of the L-shaped plate, the connecting parts and the locking parts can be used to fix the two parts of the L-shaped plate to the side and the bottom of the reinforcing structure respectively through the above two types of mounting structures, which can play a role in making the connection more stable. Moreover, the above two types of connecting parts are arranged at a certain angle (preferably perpendicular to each other), which can fix the quick-change unit from two directions and have higher reliability.

[0023] Preferably, the connecting member comprises a screw connecting member, and the locking member comprises a nut locking member, and the nut locking member is used for threaded connection with the screw connecting member.

[0024] In this solution, a screw connection piece and a nut locking piece are used, which has a simple structure, convenient and reliable connection. The screw connection piece can be a connection piece with a screw such as a bolt or a screw. The nut locking piece includes common nuts such as common hexagonal nuts and square nuts, or special nuts such as expansion nuts.

[0025] Preferably, at least a portion of the inner surface of the accommodating hole in the axial direction thereof serves as a placement groove for installing the locking member.

[0026] In the present solution, part or all of the inner surface of the accommodating hole along its axial direction is used as a placement groove, and a locking piece (the nut locking piece is preferably an expansion nut) is placed therein, and is pressed and fixed to the accommodating hole by expansion or embedding in the accommodating hole. The installation is quick and convenient, and the connection structure is simplified.

[0027] Preferably, the placement groove is formed together with the reinforcement structure by a preset locking piece, and is used to fix the preset locking piece.

[0028] In this solution, the above structural form is adopted. When the nut is made into the lower box, the nut is pre-embedded in the lower box, and the nut is formed and covered in the placement cavity of the nut. When in use, it can be directly connected to the pre-embedded nut by bolts, reducing the setting of movable parts and facilitating disassembly and assembly.

[0029] Preferably, the placement groove has a placement opening leading to the outer surface of the reinforcement structure, the placement opening is used to place the locking piece in the placement groove, and the placement groove has a movable space for the locking piece to move in a direction perpendicular to the connection direction of the locking piece and the connecting piece.

[0030] In the present solution, a placement groove with a placement opening is used, and a locking piece with a certain degree of freedom of movement is placed in the placement groove. Since the locking piece is installed after the lower box body is manufactured, and the locking piece can have a certain degree of freedom of movement in the accommodating cavity, assembly is convenient, the requirements for the processing accuracy of the lower box body are reduced, and damage to the surface of the molding mold that may be caused by the embedded locking piece can be avoided.

[0031] Preferably, a sealing groove is provided on the top surface of the reinforcement structure, and the sealing groove is used to embed a sealing strip that seals the upper cover of the battery box and the lower box body, and the placement opening of the placement groove is located in the sealing groove.

[0032] In this solution, the above-mentioned structural form is adopted, and the quick-change unit can be fixed to the reinforcement structure from the side by using the locking member. This structural form facilitates the installation of the locking member to a deeper position in the reinforcement structure, and will not cause a significant impact on the structure of the lower box body, and the locking member will not be exposed, thereby improving reliability.

[0033] Preferably, a plurality of in-groove reinforcing ribs are provided at the bottom of the sealing groove, the length direction of the in-groove reinforcing ribs is perpendicular to the length direction of the sealing groove, the placement opening of the placement groove is provided at the bottom of the groove between two adjacent in-groove reinforcing ribs in the sealing groove, and the number of the placement openings between adjacent in-groove reinforcing ribs is not more than two.

[0034] Preferably, the reinforcement structure has two oppositely arranged arms, the ends of the arms have inward-turned clamping parts, the arms and the clamping parts form the placement groove, the placement groove has a lateral opening leading to the outer surface of the reinforcement structure, and the lateral opening is used to form the placement port.

[0035] In this solution, the placement groove of the above-mentioned structural form is arranged in the reinforcement structure. The placement groove is arranged in the above-mentioned space without opening additional holes or grooves, so as to improve economic benefits and facilitate installation.

[0036] Preferably, a restraining rib is provided in the placement groove for restraining the movement of the locking member before the connecting member and the locking member are connected. The restraining rib is formed on two opposite side walls in the placement groove and abuts against the locking member, and the width of the restraining rib gradually decreases from the side wall where it is located to the locking member.

[0037] In this solution, the restraining ribs can initially restrain and position the nut placed in the placement slot, and can prevent the placed nut from falling out. The structure that gradually tapers from the side wall to the locking piece allows a small amount of movable clearance for the nut during the tightening process, thereby achieving the movement of the nut.

[0038] Preferably, the lower box body further includes a connecting plate, which is connected to the mounting structure via a connecting mechanism, and the connecting plate is fixed to a side surface of the lower box body, and the connecting plate is used to connect a quick-change unit or a battery pack fixing unit.

[0039] In the present solution, a connecting plate is provided on the reinforcing structure, and a quick-change unit or a battery pack fixing unit is provided on the connecting plate, so as to achieve a detachable quick connection between the battery pack and the electric vehicle or a fixed connection with the electric vehicle. The setting of the connecting plate makes the force more balanced and the connection more stable when the battery pack is connected to the electric vehicle through the quick-change unit or the battery pack fixing unit.

[0040] By installing the connecting mechanism through the mounting structure, the quick-change unit of the battery pack can be fixed on the lower box body, so that the battery pack containing the lower box body can be detachably connected to the electric vehicle, or the battery pack fixing unit can be fixed on the lower box body, so that the battery containing the lower box body can be fixedly connected to the electric vehicle. The lower box body is made of non-metallic composite material, which can reduce weight compared with a metal shell and has a good thermal insulation effect.

[0041] Preferably, the connecting plate is an L-shaped connecting plate having a longitudinal connecting portion and a transverse connecting portion which are perpendicular to each other, wherein the longitudinal connecting portion is connected to the side surface of the reinforcing structure, and the transverse connecting portion is connected to the bottom surface of the reinforcing structure.

[0042] In this solution, by adopting the above-mentioned structural form, the L-shaped connecting plate can be connected to the reinforcing structure from two directions, thereby improving the connection and fixing effect.

[0043] Preferably, a bottom surface of the lower box body is provided with a recessed surface, and the recessed surface is used for installing the transverse connecting portion.

[0044] In this solution, a recessed surface is provided to form a stepped surface with other parts of the bottom plate to avoid the transverse connecting portion of the L-shaped connecting plate. When the transverse connecting portion is installed on the recessed surface, the bottom surface of the battery box can be ensured to be flat.

[0045] Preferably, a glue coating groove is provided on the side surface and / or the bottom surface of the reinforcement structure, and the glue coating groove is used for coating glue to bond and fix the connecting plate.

[0046] In this solution, the above-mentioned structural form is adopted to enhance the connection and fixing effect between the connecting plate and the reinforcing structure, and the installation is convenient.

[0047] Preferably, the lower box body further comprises an inner shell body, the inner shell body is stacked in the lower box body, reinforcing ribs are provided between the inner shell body and the lower box body, and a chamber structure is formed between the inner shell body and the lower box body.

[0048] In this solution, the above structural form is adopted. Since the inner shell is stacked in the lower box to form a composite structure, the strength of the lower box is further enhanced, and the thermal insulation effect of the battery is also improved. In addition, reinforcing ribs are provided between the inner shell and the lower box, so that the structure of the lower box is strengthened to meet the strength requirements of the battery box. At the same time, the chamber structure improves the thermal insulation effect of the lower box.

[0049] A battery pack comprises an upper cover, a battery cell, a battery pack connecting unit and a lower box body of the above-mentioned battery box, wherein the lower box body has a accommodating cavity with an upper end opening, the battery cell is installed in the accommodating cavity, the upper cover is arranged on the lower box body and closes the accommodating cavity, the battery pack connecting unit is fixed on the reinforcing structure, and the battery pack connecting unit comprises a quick-change unit and a battery pack fixing unit.

[0050] In this solution, the battery pack encloses the battery unit (directly formed by combining multiple battery cells without modules, or formed by multiple battery modules composed of battery cells) in the accommodating cavity surrounded by the upper cover and the lower box body, forming a protective barrier for the battery unit and having a heat preservation effect. In addition, the lower box body of the battery pack is made of non-metallic composite material, which can reduce weight compared with the metal shell, further improving the heat preservation effect and economic benefits.

[0051] Among them, the quick-change unit includes but is not limited to: electric / liquid cooling connectors, locking mechanisms, etc. The locking mechanisms include threaded locking mechanisms (locking mechanisms that fix the battery box and the body through multiple bolts), locking pin locking mechanisms (locking mechanisms that fix the battery box and the body through locking pin locking methods), rotational locking mechanisms (locking mechanisms that fix the battery box and the body through rotational locking methods), flip locking mechanisms (locking mechanisms that fix the battery box and the body through flip locking methods), top pressure locking mechanisms (locking mechanisms that fix the battery box and the body through top pressure locking methods), staggered tooth locking mechanisms (locking mechanisms that fix the battery box and the body through staggered tooth locking methods), latch locking mechanisms (locking mechanisms that fix the battery box and the body through latch locking methods), and push-pull locking mechanisms (locking mechanisms that fix the battery box and the body through push-pull locking methods).

[0052] The battery pack fixing unit includes a bolt-type locking mechanism or other types of fixed connection mechanisms (including but not limited to mechanical, electrical or magnetic connection, etc.), etc. An electric vehicle includes the battery pack as described above.

[0053] In this solution, by installing a suitable quick-change unit or battery pack fixing unit, the battery pack can be used for quick-change electric vehicles (the battery pack can be detachably connected to the vehicle body, and the vehicle and the battery can be quickly separated), rechargeable electric vehicles (the battery pack is fixed to the vehicle body, and charging is used as the main means of replenishing energy by being loaded on the vehicle body), electric vehicles with both quick-change and charging functions, and other types of electric vehicles.

[0054] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0055] The positive and progressive effect of the present invention is that the lower box is made of non-metallic composite material, which has better heat preservation effect than the lower box made of metal, is more suitable for use in cold areas, and is lighter. The lower box forms a reinforcement structure by extending the side wall outward to enhance the strength of the side wall, which facilitates the installation structure on the reinforcement structure, and further facilitates the installation of the connection mechanism for connecting the battery pack accessories. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the structure of the lower box body of the battery box of Example 1 hiding the inner shell.

[0057] Figure 2 It is a schematic diagram of the partial structure of the sealing groove of the lower box body of the battery box of Example 1.

[0058] Figure 3 This is a schematic structural diagram of a placement slot in the lower body of the battery box of Example 1.

[0059] Figure 4 This is a schematic structural diagram of another placement groove for a hidden locking member in Example 1.

[0060] Figure 5 This is a schematic diagram of the structure of the battery box of Example 1.

[0061] Figure 6 It is a schematic diagram of the partial cross-sectional structure of the battery box of Example 1.

[0062] Figure 7 This is an enlarged view of a receiving hole in the lower body of the battery box of Example 2.

[0063] Figure 8 Schematic diagram of the exploded structure of the upper box cover of the battery box of the test example.

[0064] Description of reference numerals:

[0065] Lower box 1

[0066] Bottom plate 11

[0067] Side wall 12

[0068] Strengthening structure 121

[0069] The first reinforcement part 1211

[0070] The second reinforcement portion 1212

[0071] Sealing groove 1213

[0072] Accommodation hole 1214

[0073] Placement slot 1215

[0074] Constraint bar 12151

[0075] External reinforcement 1216

[0076] Internal reinforcement 1217

[0077] Reinforcement ribs in groove 1218

[0078] Arms 122

[0079] Clamping portion 123

[0080] Concave surface 13

[0081] Glue coating tank 14

[0082] Inner housing 15

[0083] Connectors 101

[0084] Locking member 102

[0085] Connecting plate 2

[0086] Longitudinal connection portion 21

[0087] Transverse connection part 22

[0088] Upper cover 3

[0089] Battery box 10

[0090] Box cover shell 11a

[0091] Heat insulation layer 12a

[0092] Protective layer 13a DETAILED DESCRIPTION

[0093] The present invention will be described more clearly and completely below by way of embodiments in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the embodiments.

[0094] Example 1

[0095] like Figure 1-Figure 6 As shown, the present embodiment discloses a lower box body of a battery box, which is used to form a battery pack. The lower box body 1 has a bottom plate 11 and a side wall 12 arranged around the edge of the bottom plate 11. A reinforcing structure 121 is arranged on the outer peripheral surface of the side wall 12. The side wall 12 is formed by extending outward to form the reinforcing structure 121, which enhances the strength of the side wall 12, facilitates the installation structure to be arranged on the reinforcing structure 121, and further facilitates the installation of a connecting mechanism for the connection of battery pack accessories (such as a quick-change unit or a battery pack fixing unit). When the mounting structure installs the quick-change unit, it is mainly hung on the bottom of the battery pack and the electric vehicle, which is convenient for the electric vehicle to perform battery replacement operations. When the mounting structure installs the battery pack fixing unit, it is mainly used to fix the battery pack on the electric vehicle without disassembly.

[0096] The lower box body 1 is made of a non-metallic composite material. Compared with the lower box body 1 made of metal, it has better thermal insulation effect, is more suitable for use in cold regions, and is lighter.

[0097] More specifically:

[0098] Furthermore, in this embodiment, the material of the lower box body is SMC (Sheet molding compound), which is lighter and has better heat preservation effect.

[0099] like Figure 1 and Figure 4 As shown, further, in this embodiment, the reinforcement structure 121 includes a first reinforcement part 1211, a second reinforcement part 1212 and a plurality of external reinforcement ribs 1216, the first reinforcement part 1211 and the second reinforcement part 1212 are arranged one above and one below around the side wall 12, and the plurality of external reinforcement ribs 1216 are arranged between the first reinforcement part 1211 and the second reinforcement part 1212 along the circumferential direction of the side wall 12. The first reinforcement part 1211 and the second reinforcement part 1212 strengthen the strength of the side wall 12 of the lower box body 1 in the circumferential direction. The external reinforcement rib 1216 is arranged between the first reinforcement part 1211 and the second reinforcement part 1212 to strengthen the strength of the side wall 12 in the vertical direction. The structural form of the first reinforcement part 1211, the second reinforcement part 1212 and the plurality of external reinforcement ribs 1216 enhances the strength of the side wall 12 of the lower box body 1 in the circumferential and vertical directions, and is conducive to the lightweight structure of the lower box body 1. Furthermore, in this embodiment, the first reinforcement part 1211 and the second reinforcement part 1212 are plate-like structures extending horizontally outward, the thickness of the first reinforcement part 1211 is greater than the thickness of the second reinforcement part 1212, and the connecting mechanism in the side direction of the lower box body is mainly arranged on the first reinforcement part 1211 or on the physical structure relying on the first reinforcement part 1211.

[0100] like Figure 1 As shown, a plurality of external reinforcing ribs 1216 separate the space between the first reinforcing portion 1211 and the second reinforcing portion 1212 into a plurality of regions, which helps to improve the thermal insulation performance of the lower box 1. Furthermore, in this embodiment, each region is generally in the shape of a cuboid.

[0101] like Figure 1As shown, in this embodiment, the inner surface of the bottom plate 11 and the inner surface of the side wall 12 are provided with staggered internal reinforcing ribs 1217. The internal reinforcing ribs 1217 on the inner side of the lower box 1 and the peripheral reinforcing structure 121 are used to improve the overall strength of the lower box 1, and it is also convenient to form a cavity between the internal reinforcing ribs 1217 and in the frame of the reinforcing structure 121, and a heat-insulating material can be placed in the cavity to improve the heat-insulating effect of the lower box 1. Furthermore, the internal reinforcing ribs 1217 are arranged vertically and horizontally on the bottom surface of the lower box, and only vertical reinforcing ribs are provided on the side of the lower box.

[0102] like Figure 1 As shown, further, in this embodiment, part of the external reinforcement ribs 1216 are arranged at positions corresponding to the internal reinforcement ribs 1217 to form corresponding reinforcement structures inside and outside the lower box body 1 to enhance the overall strength of the lower box body 1.

[0103] Furthermore, in this embodiment, a plurality of mounting structures for mounting the connecting mechanism are provided on the reinforcing structure 121 .

[0104] Furthermore, if Figure 1 and Figure 3 As shown, the mounting structure includes a receiving hole 1214 and a placement groove 1215 disposed in the reinforcement structure 121, the receiving hole 1214 is connected to the placement groove 1215, and the receiving hole 1214 has one end leading to the outer surface of the reinforcement structure 121; the receiving hole 1214 and the placement groove 1215 are respectively used to install the connecting member 101 and the locking member 102 constituting the connecting mechanism, so that the connecting member 101 is connected to the locking member 102 located in the placement groove 1215 through the receiving hole 1214. There are a plurality of receiving holes 1214, each of which has one end leading to the outer surface of the side portion of the reinforcement structure 121, and the connecting member 101 is connected to the locking member 102 in the placement groove 1215 through the receiving hole 1214.

[0105] Furthermore, in the present embodiment, the number of the accommodating holes is several, a part of the accommodating holes has one end leading to the outer surface of the side of the reinforcing structure, and the other part of the accommodating holes has one end leading to the outer surface of the bottom of the reinforcing structure. The mounting structure, in cooperation with the connecting member and the locking member, can connect the quick-change unit from both the side and the bottom. When the quick-change unit is connected to the battery box through the structural member of the L-shaped plate, the longitudinal connecting plate (attached to the side surface of the reinforcing structure) and the bottom extension plate (flipped downward to surround the bottom edge of the lower box body) of the L-shaped plate can be fixedly connected to the side and bottom of the reinforcing structure through the above two forms of mounting structures, which can play a role in making the connection more stable. Moreover, the above two forms of connecting members are perpendicular to each other, which can fix the quick-change unit from two directions and have higher reliability.

[0106] like Figure 2 , Figure 4 and Figure 6 As shown, the connector 101 includes a screw connector, and the locking member 102 includes a nut locking member, and the nut locking member is used for threaded connection with the screw connector. In this embodiment, the screw connector and the nut locking member are used, which has a simple structure, convenient connection, and reliability. Furthermore, the screw connector adopts a connector 101 with a screw such as a bolt or a screw. The nut locking member adopts a square nut. The square nut can prevent the nut connector from rotating in the placement groove 1215 after being placed in the placement groove 1215 to the greatest extent.

[0107] In this embodiment, a placement groove 1215 with a placement opening is used, and a locking piece with a certain degree of freedom of movement is placed in the placement groove 1215. Since the locking piece is installed after the lower box body 1 is manufactured, and the locking piece can have a certain degree of freedom of movement in the accommodating cavity, assembly is convenient, which reduces the requirements for the processing accuracy of the lower box body 1 and can avoid damage to the surface of the molding mold caused by the embedded locking piece.

[0108] Furthermore, in this embodiment, one end of the receiving hole 1214 of the mounting structure for fixing the quick-change unit from the side leads to the outer surface of the side portion of the reinforcement structure. Figure 4 As shown, a thickened structure is provided at the intersection of the first extension portion 1211 and the external reinforcement rib 1216, and at the position of the portion exposed in the area separated by the external reinforcement rib 1216, so as to increase the strength of the connection. In this case, the placement groove 1215 of the above-mentioned mounting structure extends downward from the top of the reinforcement structure to communicate with the other end of the accommodating hole 1214. By using a locking member, the quick-change unit can be fixed to the reinforcement structure 121 from the side through the mounting structure.

[0109] like Figure 1 , Figure 2 and Figure 3 As shown, further, in this embodiment, a sealing groove 1213 is provided on the top surface of the reinforcing structure 121, and the sealing groove 1213 is used to embed a sealing strip that seals the upper cover 3 of the battery box 10 and the lower box body 1, and the placement opening of the placement groove 1215 is located in the sealing groove 1213. This structural form facilitates the installation of the locking member to a deeper position in the reinforcing structure 121, and will not cause a significant impact on the structure of the lower box body 1, and the locking member 102 will not be exposed, thereby improving reliability.

[0110] like Figure 2As shown, further, a plurality of groove reinforcing ribs 1218 are provided at the bottom of the sealing groove 1213, and the length direction of the groove reinforcing ribs 1218 is perpendicular to the length direction of the sealing groove 1213. The placement opening of the placement groove 1215 is set at the groove bottom between two adjacent groove reinforcing ribs 1218 in the sealing groove 1213, and the number of placement openings between adjacent groove reinforcing ribs 1218 is not more than two, so as to avoid too many placement openings being set to affect the strength of the reinforced structure.

[0111] In this embodiment, Figure 4 Another form of placement groove 1215 is shown. In order to show the structure of the placement groove 1215, the nut locking member in the placement groove 1215 is hidden. The placement groove 1215 has a placement opening leading to the outer surface of the reinforcement structure 121. The placement opening is used to place the locking member (not shown in the figure) in the placement groove 1215. The placement groove 1215 has a movable space for the locking member to move in a direction perpendicular to the connection direction of the locking member and the connecting member 101. By using the locking member, the quick-change unit can be fixed to the reinforcement structure 121 from the side through the mounting structure. Furthermore, the reinforcement structure 121 has two oppositely arranged arms 122, and the ends of the arms 122 have an inverted clamping portion 123. The arms 122 and the clamping portion 123 form the placement groove 1215. The placement groove 1215 has a lateral opening leading to the outer surface of the reinforcement structure 121, and the lateral opening is used to form the placement opening. The placement groove 1215 is disposed in the reinforcement structure 121 , and no additional holes or grooves need to be provided, which facilitates installation.

[0112] like Figure 3 and Figure 4 As shown, both placement grooves 1215 are provided with restraining ribs 12151 for restraining the movement of the locking member 102 before the connection between the connecting member 101 and the locking member 102. The restraining ribs 12151 are formed on two opposite side walls 12 in the placement groove 1215 and abut against the locking member 102. The width of the restraining ribs 12151 from the side wall 12 where they are located to the locking member 102 gradually decreases. The restraining ribs 12151 can perform preliminary restraint and positioning on the nuts placed in the placement groove 1215, and can prevent the placed nuts from falling out. The structure that gradually tapers from the side wall to the locking member 102 allows a small amount of displacement of the nut during the tightening process, thereby realizing the movement of the nut.

[0113] like Figure 6As shown, the lower box 1 also includes a connecting plate 2, which is connected to the mounting structure through a connecting mechanism, and the connecting plate 2 is fixed to the side of the lower box 1, and the connecting plate 2 is used to connect the quick-change unit. In this embodiment, by arranging the connecting plate 2 on the reinforcing structure 121 and arranging the quick-change unit on the connecting plate 2, the detachable and quick connection between the battery pack and the electric vehicle is realized. The arrangement of the connecting plate 2 makes the force more balanced and the connection more stable when the battery pack is connected to the electric vehicle through the quick-change unit. By installing the connecting mechanism through the mounting structure, the quick-change unit of the battery pack can be fixed on the lower box 1, so that the battery pack containing the lower box 1 can be detachably connected to the electric vehicle, so that the battery containing the lower box 1 can be fixedly connected to the electric vehicle, and the lower box 1 is made of a non-metallic composite material, which can reduce the weight compared with a metal shell and has a good thermal insulation effect.

[0114] like Figure 6 As shown, further, in this embodiment, the connecting plate 2 is an L-shaped connecting plate 2, and the L-shaped connecting plate 2 has a longitudinal connecting portion 21 and a transverse connecting portion 22 that are perpendicular to each other, the longitudinal connecting portion 21 is connected to the side of the reinforcing structure 121, and the transverse connecting portion 22 is connected to the bottom surface of the reinforcing structure 121. The L-shaped connecting plate 2 can be connected to the reinforcing structure 121 from two directions to improve the connection and fixing effect.

[0115] Furthermore, in this embodiment, a concave surface 13 is provided on the bottom surface of the lower box body 1, and a step surface is formed between the concave surface 13 and other parts of the bottom plate 11, and the concave surface 13 is used to install the transverse connecting portion 22. When the transverse connecting portion 22 is installed on the reinforcement structure, the concave surface 13 is provided to avoid the transverse connecting portion 22 of the L-shaped connecting plate 2, so that the bottom surface of the battery box 10 is smoother.

[0116] Furthermore, glue grooves 14 are provided on the side surfaces and the bottom surfaces of the reinforcing structure 121, and the glue grooves 14 are used for applying glue to bond and fix the connecting plate 2, thereby enhancing the connection and fixing effect between the connecting plate 2 and the reinforcing structure 121 and facilitating installation.

[0117] like Figure 6As shown, in this embodiment, the lower box body 1 also includes an inner shell 15, the inner shell 15 is stacked in the lower box body 1, and a reinforcing rib is provided between the inner shell 15 and the lower box body 1, and a chamber structure is formed between the inner shell 15 and the lower box body 1. In this embodiment, since the inner shell 15 is stacked in the lower box body 1 to form a composite structure, the strength of the lower box body 1 is further strengthened, and the thermal insulation effect of the battery is also improved. In addition, reinforcing ribs are provided between the inner shell 15 and the lower box body 1, so that the structure of the lower box body 1 is strengthened to meet the strength requirements of the battery box 10. At the same time, the chamber structure improves the thermal insulation effect of the lower box body 1, and the lower box body 1 is made of non-metallic composite materials, which further enhances the thermal insulation performance compared with the metal material shell. In this embodiment, the lower box body 1 is made of SMC material. Compared with the metal material lower box body 1, the non-metallic composite material lower box body 1 has better thermal insulation performance, lighter weight than the metal material box body, simpler production process, and improved economic benefits.

[0118] This embodiment also discloses a battery pack, which includes an upper cover 3, a battery cell, a battery pack connection unit and the lower box body 1 of the above-mentioned battery box, the lower box body 1 has a accommodating cavity with an upper end opening, the battery cell is installed in the accommodating cavity, the upper cover 3 is arranged on the lower box body 1 and closes the accommodating cavity, the battery pack connection unit is fixed on the reinforcement structure 121, and the battery pack connection unit includes a quick-change unit. In this embodiment, the battery pack encloses the battery cell (composed of a plurality of battery modules composed of battery cells) in the accommodating cavity surrounded by the upper cover 3 and the lower box body 1, forming a protective barrier for the battery cell and having a heat preservation effect. In addition, the lower box body 1 of the battery pack is made of non-metallic composite material, which can reduce weight compared with a metal shell, and further improve the heat preservation effect and economic benefits.

[0119] This embodiment also discloses an electric vehicle, which includes the battery pack as described above. The electric vehicle is a quick-change electric vehicle (the battery pack is detachably connected to the vehicle body, and the vehicle and the battery can be quickly separated).

[0120] Example 2

[0121] like Figure 7As shown, this embodiment is basically the same as the embodiment 1, except that, in this embodiment, at least a portion of the inner surface of the receiving hole 1214 in the axial direction is used as a placement groove 1215 (that is, the placement groove 1215 is a part of the receiving hole 1214) for installing the locking member 102. In this embodiment, a portion of the inner surface of the receiving hole 1214 in the axial direction is used as the placement groove 1215, and the locking member 102 is placed therein. The locking member 102 is preferably an expansion nut in this embodiment, which is compressed and fixed with the receiving hole 1214 by expansion or embedding in the receiving hole 1214, which is fast and convenient to install, and simplifies the connection structure. However, compared with the installation structure setting method of the embodiment 1, the installation structure setting method of the embodiment 2 is more complicated in the installation process of the locking member 102, and the expansion nut is usually heavier than the square nut.

[0122] Example 3

[0123] The placement groove can be formed by a preset locking piece and a reinforcing structure to fix the preset locking piece. When the nut is made in the lower box, the nut is pre-embedded in the lower box and is formed to cover the placement cavity of the nut. When in use, it can be directly connected to the embedded nut by bolts, which reduces the setting of moving parts and is easy to disassemble and assemble. However, this fixing form of the installation structure has relatively high requirements on the processing accuracy of the lower box, and the prefabricated nut is easy to cause damage to the molding mold of the lower box.

[0124] In addition to the above embodiments, in other embodiments, the following may also be done:

[0125] The area formed by the external reinforcement rib 1216 separating the space between the first reinforcement part 1211 and the second reinforcement part 1212 can be filled with a lightweight thermal insulation material.

[0126] The above-mentioned lightweight thermal insulation materials include but are not limited to: polymer foam materials, aerogel felts, etc. Polymer foam materials refer to microporous materials based on polymers (plastics, rubbers, elastomers or natural polymer materials) with countless bubbles inside. Typical polymer foam materials include polyurethane foam, polystyrene foam, etc. Preferably, the above-mentioned lightweight thermal insulation material uses aerogel felt.

[0127] The inner surface of the bottom plate and / or the inner surface of the side wall may be provided with internal reinforcing ribs arranged at intervals or in a staggered manner. The internal reinforcing ribs may be provided only on the inner surface of the bottom plate, or may be provided on both the inner surface of the bottom plate and the inner surface of the side wall, so as to strengthen the bottom plate and the side wall of the lower box.

[0128] The inner shell may not be provided inside the lower box body. In the case where the inner shell is provided, the chamber for placing the battery can be made more regular, and the strength of the lower box body can also be improved to a certain extent.

[0129] The receiving hole 1214 may have only one end leading to the side outer surface or the bottom outer surface of the reinforcing structure 121. When the receiving hole 1214 has only one end leading to the side outer surface of the reinforcing structure 121, the connection to the quick-change unit or the battery pack fixing unit can be achieved from the side. When the receiving hole 1214 has only one end leading to the bottom outer surface of the reinforcing structure 121, the connection to the quick-change unit or the battery pack fixing unit can be achieved from the bottom.

[0130] The connection plate used to connect the quick-change unit or the battery pack fixing unit to the lower box body may also have only a longitudinal connection plate, or only a bottom extension plate. In the case where the connection plate is an L-shaped plate, the longitudinal connection plate and the bottom extension plate may present other angles.

[0131] The screw connection of the connection member 101 may also be a connection member with a screw such as a screw, and the nut locking member may also be a hexagonal nut, an expansion nut, etc.

[0132] The groove bottom of the sealing groove 1213 may not be provided with the groove reinforcing rib 1218 .

[0133] The glue coating groove may be provided on the side surface or the bottom surface of the reinforcing structure.

[0134] A circular avoidance hole matching the lock shaft of the quick-change unit may be provided in the area separated by the external reinforcement rib 1216 , and the avoidance hole at least connects the first connection portion and the second connection portion.

[0135] The reinforcing structure 121 of the lower box body may also be installed with a quick-change unit of other structures, or a battery pack fixing unit. The quick-change unit of other structures is used for detachable connection with the electric vehicle, and the battery pack fixing unit is used for fixed connection with the electric vehicle. Among them, other quick-change units include but are not limited to: electric / liquid cooling connectors, locking mechanisms (battery pack ends), etc. The electric / liquid cooling connector includes an electric connector and / or a liquid cooling connector. The electric connector is used for electrical connection with the electric vehicle. The liquid cooling connector is mainly used as an interface for connecting the liquid cooling mechanism with the electric vehicle when a liquid cooling mechanism is used inside the battery pack, so as to cool the battery pack and improve safety. The locking mechanism (battery pack end) includes a threaded locking mechanism (a locking mechanism that fixes the battery box to the vehicle body by multiple bolts), a locking pin locking mechanism (a locking mechanism that fixes the battery box to the vehicle body by a locking pin locking method), a rotating locking mechanism (a locking mechanism that fixes the battery box to the vehicle body by a rotating locking method), a flip locking mechanism (a locking mechanism that fixes the battery box to the vehicle body by a flip locking method), a top pressing locking mechanism (a locking mechanism that fixes the battery box to the vehicle body by a top pressing locking method), other types of staggered tooth locking mechanisms (locking mechanisms that fix the battery box to the vehicle body by staggered tooth locking methods), a latch locking mechanism (locking mechanisms that fix the battery box to the vehicle body by latch locking methods), a push-pull locking mechanism (locking mechanisms that fix the battery box to the vehicle body by a push-pull locking method), etc., which are provided at the battery pack end (relative to the vehicle end). The fixing unit includes a bolt-type locking mechanism or other types of fixed connection mechanisms (including but not limited to mechanical, electrical connection or magnetic connection, etc.).

[0136] By installing a suitable quick-change unit or battery pack fixing unit, the battery pack can be used for quick-change electric vehicles (the battery pack is detachably connected to the vehicle body, allowing for rapid separation of the vehicle and the battery), rechargeable electric vehicles (the battery pack is fixed to the vehicle body, with charging as the main means of replenishing energy), electric vehicles with both quick-change and charging functions, and other types of electric vehicles.

[0137] The material of the lower box body may also be other light-weight, high-strength, and high-temperature-performance polymer composite materials, preferably, the polymer composite material is a fiber-reinforced resin-based composite material. The fiber-reinforced resin-based composite material may be a carbon fiber-reinforced resin-based composite material, and / or a resin fiber-reinforced resin-based composite material, and / or a ceramic fiber-reinforced resin-based composite material, and / or other types of glass fiber-reinforced resin-based composite materials.

[0138] Test example

[0139] A quick-swap electric vehicle currently uses a sheet metal battery pack (using mica sheets as insulation material), which weighs 371.5kg. Prepare a non-metallic composite battery pack with the same size specifications (external dimensions and internal space dimensions of the battery box).

[0140] The non-metal composite lower box in Example 1 is used, and the height of the chamber structure between the lower box and the inner shell (i.e., the distance between the surfaces opposite to the lower box and the inner shell) is 5 mm. The lower box formed when no aerogel is placed in the chamber structure is recorded as the non-metal composite lower box A, and the lower box formed when the aerogel is placed in the chamber structure is recorded as the non-metal composite lower box B. The non-metal composite lower box A and the non-metal composite lower box B are respectively combined with the upper box cover by snap-fitting to form a non-metal composite battery box (see Figure 5 ), respectively recorded as non-metallic composite material battery box A and non-metallic composite material battery box B, which are respectively loaded with battery modules and necessary electrical components to form non-metallic composite material battery pack A and non-metallic composite material battery pack B.

[0141] like Figure 8 As shown, the non-metallic composite upper cover 3 used to form a non-metallic composite battery box with the non-metallic composite lower box A and the non-metallic composite lower box B respectively includes: a box cover shell 11a, a heat insulating layer 12a and a protective layer 13a. The heat insulating layer 12a and the protective layer 13a sequentially cover and are fixed to the box cover shell 11a facing the lower box. The box cover shell 11a is made of SMC, the heat insulating layer 12a is made of aerogel felt with a thickness of 5 mm, and the protective layer 13a is made of fireproof cloth. The box cover shell 11a and the heat insulating layer 12a, as well as the heat insulating layer 12a and the protective layer 13a are connected by structural adhesive bonding, and a concave-convex structure is provided on the box cover shell 11a to increase the strength. The upper cover 3 and the lower box are sealed by a U-shaped sealing method. The side of the upper cover 3 is provided with a recessed portion, which cooperates with the raised portion provided on the side of the lower box to form a snap connection (the U-shaped sealing and snap connection are shown in FIG. Figure 6 As shown), the upper cover 3 and the lower box cover are molded at one time to achieve the buckling of the snap connection structure.

[0142] Non-metal composite battery pack A, non-metal composite battery pack B and sheet metal battery pack of the same size and specifications were tested.

[0143] In terms of weight testing, the mass of the non-metallic composite lower box B is 45kg, while the mass of the sheet metal lower box of the same size (using mica sheets as insulation material) is 60.4kg. Compared with the sheet metal lower box, the non-metallic composite lower box B has a weight reduction of 25.5%. The weight of the non-metallic composite battery box B is 57.8kg, and the weight of the sheet metal battery box is 70.772kg. The weight advantage of the non-metallic composite battery box is obvious. Compared with the non-metallic composite lower box B, the non-metallic composite lower box A lacks the aerogel felt placed in the chamber structure. Since the density of the aerogel felt is small and the amount used is not large, the mass of the non-metallic composite lower box A is equivalent to that of the non-metallic composite lower box B, which is slightly reduced (almost negligible). In terms of the overall weight of the battery pack, the overall weight of the non-metallic composite battery pack A and the non-metallic composite battery pack B is reduced by 2-3% compared with the sheet metal battery pack, and the weight advantage is obvious.

[0144] In terms of strength testing, the non-metal composite lower box A and non-metal composite lower box B, as well as the non-metal composite upper cover used to form a composite non-metal battery box, all meet the strength and other requirements specified in GB / T 31467.3-2015 "Lithium-ion power battery packs and systems for electric vehicles Part 3: Safety requirements and test methods" (the actual test can reach 1.5 times the standard). They can be used in electric vehicles.

[0145] In terms of thermal insulation and heat preservation performance: the initial temperature inside the package is 20-30℃, and it is placed in an environment of 7-9℃ for 600 minutes. The cumulative temperature change rate (cumulative cooling rate) of the battery cells in the non-metallic composite battery pack A is lower than 50% of that in the sheet metal battery pack (the temperature of the battery cells is measured by optical fiber), and the cumulative temperature change rate of the battery cells in the non-metallic composite battery pack B is only about 40% of that in the sheet metal battery pack. At lower temperatures, this advantage is more obvious. When used in cold northern regions, it can ensure that the temperature of the battery cells is at an optimal operating temperature. Moreover, after testing, non-metallic composite battery pack A and non-metallic composite battery pack B can withstand high temperatures of 1000℃. In the test simulating battery fire, even if the battery is completely burned, the non-metallic composite box remains basically intact throughout the test, with only smoke but no open flames.

[0146] The cell placement cavity of non-metallic composite battery pack A and non-metallic composite battery pack B is filled with thermal conductive glue (the height of the thermal conductive glue is about 1 / 3 of the battery height), which increases the temperature uniformity between the cells and avoids thermal runaway caused by abnormal temperature of individual cells. Secondly, it also makes the cells (or battery modules formed by cells) inside the battery box form a whole, increasing the overall strength of the battery pack. Compared with the sheet metal battery pack in the above case, the non-metallic composite material battery pack B has a cumulative temperature rise of more than 5°C when charged with a charging current of 40A (SOC from 0-100%) in the same environment. The non-metallic composite material battery pack B has a charging capacity that is more than 5% higher than the sheet metal battery pack, and the maximum temperature difference inside the box of the composite non-metal battery pack (obtained by recording the temperature of all positive and negative ears) is maintained at a uniformity of 1.5-2°C. This is not only related to the use of thermal conductive adhesive, but also related to the fact that the specific heat capacity and thermal insulation performance of SMC are higher than those of sheet metal materials. The above factors make the non-metallic composite material battery pack of this application more advantageous than the sheet metal battery pack in avoiding thermal runaway.

[0147] The properties of some of the raw materials used in the above test examples are as follows:

[0148] SMC meets the following performance requirements: Material grade (disordered glass fiber state) tensile strength ≥70Mpa (GB / T 1447-2005), flexural strength ≥160MPa (GB / T 1449-2005), impact toughness ≥55KJ / m 2 (GB / T 1451-2005), elongation at break ≥1.3% (GB / T 1447-2005).

[0149] The density of aerogel felt is about 0.16 mg / cm 3 .

[0150] Structural adhesive shear strength (anodized aluminum-anodized aluminum) ≥ 6MPa, tensile strength ≥ 5MPa, flame retardant grade V0.

[0151] The above-mentioned SMC, aerogel felt and structural adhesive can be commercially available products or homemade products that meet the above performance requirements, and the remaining materials are commercially available products.

[0152] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A lower box of a battery box, used to form a battery pack, characterized in that: The lower box body is made of a non-metallic composite material, and has a bottom plate and a side wall arranged around the edge of the bottom plate, and a reinforcement structure is arranged on the outer peripheral surface of the side wall, and the side wall is formed by extending outward to form the reinforcement structure, and a plurality of mounting structures for mounting the connection mechanism are arranged on the reinforcement structure; The mounting structure comprises a receiving hole and a placement groove provided in the reinforcement structure, the receiving hole is communicated with the placement groove, and the receiving hole has one end leading to the outer surface of the reinforcement structure; the receiving hole and the placement groove are respectively used to install a connecting member and a locking member constituting the connecting mechanism, so that the connecting member is connected to the locking member located in the placement groove through the receiving hole; The number of the accommodating holes is several, and each of the accommodating holes has an end leading to the outer surface of the side portion of the reinforcing structure; Alternatively, the number of the accommodating holes is several, a portion of the accommodating holes has an end leading to the side outer surface of the reinforcing structure, and the remaining portion of the accommodating holes has an end leading to the bottom outer surface of the reinforcing structure; The placement groove is provided with a restraining rib for restraining the movement of the locking member before the connecting member is connected to the locking member. The restraining rib is formed on two opposite side walls in the placement groove and abuts against the locking member, and the width of the restraining rib gradually decreases from the side wall where the restraining rib is located to the locking member. The lower box body also includes a connecting plate, which is connected to the mounting structure via a connecting mechanism. The connecting plate is fixed to the side of the lower box body, and is used to connect the quick-change unit or the battery pack fixing unit.

2. The lower box of the battery box as claimed in claim 1, characterized in that: The reinforcement structure includes a first reinforcement part, a second reinforcement part and a plurality of external reinforcement ribs. The first reinforcement part and the second reinforcement part are arranged one above and one below around the side wall, and the plurality of external reinforcement ribs are arranged between the first reinforcement part and the second reinforcement part along the circumferential direction of the side wall.

3. The lower box of the battery box as claimed in claim 2, characterized in that: The plurality of external reinforcing ribs divide the space between the first reinforcing portion and the second reinforcing portion into a plurality of regions, and the regions are filled with lightweight thermal insulation material.

4. The lower box of the battery box as claimed in claim 2, characterized in that: The inner surface of the bottom plate is provided with internal reinforcing ribs arranged at intervals or in a staggered manner; Alternatively, the inner surface of the bottom plate and the inner surface of the side wall are provided with internal reinforcing ribs arranged at intervals or in a staggered manner.

5. The lower box body of the battery box according to claim 4, characterized in that: At least a portion of the external reinforcing ribs are disposed at positions corresponding to the internal reinforcing ribs.

6. The lower box of the battery box according to claim 1, characterized in that: The connecting piece includes a screw connecting piece, and the locking piece includes a nut locking piece, and the nut locking piece is used for threaded connection with the screw connecting piece.

7. The lower box body of the battery box according to claim 1, characterized in that: At least a portion of the inner side surface of the accommodating hole in the axial direction thereof serves as a placement groove for installing the locking member.

8. The lower box of the battery box according to claim 1, characterized in that: The placement groove is formed together with the reinforcement structure by the preset locking piece and is used to fix the preset locking piece.

9. The lower box of the battery box according to claim 1, characterized in that: The placement groove has a placement opening leading to the outer surface of the reinforcement structure, and the placement opening is used to place the locking member in the placement groove. The placement groove has a movable space for the locking member to move in a direction perpendicular to the connection direction between the locking member and the connecting member.

10. The lower box of the battery box according to claim 9, characterized in that: A sealing groove is provided on the top surface of the reinforcement structure, and the sealing groove is used to embed a sealing strip that seals the upper cover of the battery box and the lower box body, and the placement opening of the placement groove is located in the sealing groove.

11. The lower box of the battery box according to claim 10, characterized in that: The bottom of the sealing groove is provided with a plurality of in-groove reinforcing ribs, the length direction of the in-groove reinforcing ribs is perpendicular to the length direction of the sealing groove, the placement opening of the placement groove is arranged at the bottom of the groove between two adjacent in-groove reinforcing ribs in the sealing groove, and the number of the placement openings between adjacent in-groove reinforcing ribs is not more than two.

12. The lower box of the battery box according to claim 9, characterized in that: The reinforcing structure has two arms arranged opposite to each other, the ends of the arms have inward-turned clamping parts, the arms and the clamping parts form the placement groove, the placement groove has a lateral opening leading to the outer surface of the reinforcing structure, and the lateral opening is used to form the placement port.

13. The lower box of the battery box according to claim 1, characterized in that: The connecting plate is an L-shaped connecting plate having a longitudinal connecting portion and a transverse connecting portion which are perpendicular to each other, wherein the longitudinal connecting portion is connected to the side surface of the reinforcing structure, and the transverse connecting portion is connected to the bottom surface of the reinforcing structure.

14. The lower box of the battery box according to claim 13, characterized in that: The bottom surface of the lower box body is provided with a recessed surface, and the recessed surface is used for installing the transverse connecting part.

15. The lower box of the battery box according to claim 1, characterized in that: The side surface and / or the bottom surface of the reinforcing structure is provided with a glue coating groove, and the glue coating groove is used for coating glue to bond and fix the connecting plate.

16. The lower box of the battery box according to any one of claims 1 to 12, characterized in that: The lower box body also includes an inner shell body, the inner shell body is stacked in the lower box body, reinforcing ribs are arranged between the inner shell body and the lower box body, and a chamber structure is formed between the inner shell body and the lower box body.

17. A battery pack, characterized in that: It includes an upper cover, a battery cell, a battery pack connecting unit and a lower box body of a battery box as described in any one of claims 1-16, the lower box body has a accommodating cavity with an upper end opening, the battery cell is installed in the accommodating cavity, the upper cover is arranged on the lower box body and closes the accommodating cavity, the battery pack connecting unit is fixed on the reinforcing structure, and the battery pack connecting unit includes a quick-change unit and a battery pack fixing unit.

18. An electric vehicle, characterized in that: The electric vehicle comprises the battery pack as claimed in claim 17.

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