WO2023116732A1 - Lower box body of battery box, and battery pack and electric vehicle - Google Patents

Abstract

Disclosed are a lower box body of a battery box, and a battery pack and an electric vehicle. The lower box body of the battery box is used for forming the battery pack; the lower box body is made of a non-metal composite material; the lower box body is provided with a bottom plate and a side wall provided around the edge of the bottom plate; a reinforcing structure is disposed on the peripheral surface of the side wall; the side wall extends outwards to form the reinforcing structure; and the reinforcing structure is provided with a plurality of mounting structures used for mounting a connecting mechanism. The lower box body is made of the non-metal composite material, and compared with a lower box body made of a metal material, the lower box body is better in heat preservation effect, more suitable for being used in cold regions and lighter in weight. For the lower box body, the side wall extends outwards to form a reinforcing structure, enhancing the strength of the side wall, facilitating the provision of the mounting structures on the reinforcing structure, and further facilitating the mounting of the connecting mechanism for connecting a battery pack accessory (such as a quick-change unit or a battery pack fixing unit).

Description

Lower box body of battery box, battery pack and electric vehicle

This application claims the priority of Chinese patent application 202111567173.8 with a filing date of December 20, 2021 and the priority of Chinese patent application 202111668441.5 with a filing date of December 31, 2021. This application cites the full text of the above-mentioned Chinese patent application.

technical field

The invention relates to the field of electric vehicle battery replacement, in particular to a lower box body of a battery box, a battery pack and an electric vehicle.

Background technique

Electric vehicles have the advantages of zero emission, low noise, and very economical operation and maintenance, and are increasingly favored by users. The energy used by an electric vehicle is the electric energy provided by its own battery pack, and the electric vehicle needs to be charged after the electric energy is used up. The battery pack installation methods of electric vehicles are generally divided into fixed type and replaceable type. Among them, the fixed type battery pack is generally fixed on the vehicle, and the vehicle is directly used as the charging object when charging. The replaceable battery pack is generally fixed on the bracket of the vehicle by means of movable installation, and the battery pack can be removed to perform replacement or charging operations separately. After the replaced battery pack is charged, it can be installed on the on the vehicle.

The existing connection mechanism of the battery box is arranged on the shell of the battery box, which causes the shell of the battery box to be under a relatively large force. After a long time of use, the shell of the battery box is easily deformed and the connection is unreliable. Moreover, the shell of the existing battery pack is made of metal, which results in poor heat preservation effect of the battery pack, and the temperature of the battery pack is likely to change with the change of the ambient temperature. Especially when the battery pack is used in a cold area, when the ambient temperature is low, the temperature of the battery cells inside the battery pack drops faster, and the performance of the battery pack decreases more significantly.

Contents of the invention

The technical problem to be solved by the present invention is to provide a lower box body of the battery box, a battery pack and an electric vehicle in order to overcome the defect that the battery box shell in the prior art is weak and inconvenient to install a connection structure.

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

A lower box body of a battery box is used to form a battery pack, the lower box body is made of non-metallic composite material, the lower box body has a bottom plate and side walls arranged around the edge of the bottom plate, the outer periphery of the side wall A reinforcement structure is provided on the surface, and the side wall is extended outward to form the reinforcement structure, and several installation structures for installing the connection mechanism are provided on the reinforcement structure.

In this solution, the lower box body is made of non-metallic composite material. Compared with the lower box body made of metal, it has better thermal insulation effect, is more suitable for use in cold regions, and is lighter in weight. The lower box forms a reinforced structure by extending the side wall outwards, which enhances the strength of the side wall, facilitates the installation structure on the reinforced structure, and further facilitates the installation of the connecting mechanism, which is used for battery pack accessories (such as quick-change units or battery packs). unit) connections.

Preferably, the reinforcement structure includes a first reinforcement part, a second reinforcement part and several external reinforcement ribs, the first reinforcement part and the second reinforcement part are arranged at intervals around the side wall one above the other, and the several The external reinforcing ribs are arranged at intervals along the circumferential direction of the side wall between the first reinforcing part and the second reinforcing part.

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 side wall in the vertical direction. direction strength. By adopting the above structural form, the strength of the side wall of the lower box body in the circumferential and vertical directions is enhanced, and it is also beneficial to the lightweight of the lower box body structure.

Preferably, several of the external reinforcement ribs divide the space between the first reinforcement part and the second reinforcement part into a plurality of regions, and the regions are filled with lightweight thermal insulation materials.

In this scheme, the space formed in the reinforced structure is used to fill the lightweight thermal insulation material, which helps to improve the thermal insulation performance of the lower box. Lightweight insulation materials include, but are not limited to: polymer foam, airgel felt, and the like. Polymer foaming material refers to a microporous material with numerous bubbles inside it based on polymer (plastic, rubber, elastomer or natural polymer material). Typical polymer foaming materials such as polyurethane (Polyurethane) foam, Polystyrene foam, etc. Preferably said polymeric foam material is polyurethane foam.

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

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

In this solution, the internal reinforcing rib can be provided only on the inner surface of the bottom plate, or can be provided on the inner surface of the bottom plate and the inner surface of the side wall at the same time. The bottom plate (and the side wall) of the lower box body can be reinforced through the above arrangement. The overall strength of the lower box is improved by using the internal reinforcement ribs inside the lower box and the surrounding reinforcement structure, and it is also convenient to form a cavity between the internal reinforcement ribs and/or in the frame of the reinforcement structure. Insulation material is placed in the middle to improve the insulation effect of the lower box.

Preferably, at least a part of the external reinforcing ribs is arranged at a position corresponding to the internal reinforcing ribs.

In this solution, corresponding reinforcement structures are formed inside and outside the lower box to enhance the overall strength of the lower box.

Preferably, the installation structure includes an accommodating hole and a placement groove arranged in the reinforcement structure, the accommodating hole communicates with the placement groove, and the accommodating hole has a One end of the outer surface; the accommodating hole and the placement groove are respectively used to install the connecting piece and the locking piece that constitute the connecting mechanism, so that the connecting piece passes through the accommodating hole and is located in the placing groove Connected with the locking piece in.

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

Preferably, there are several accommodating holes, and each accommodating hole has one end leading to the side outer surface of the reinforcing structure;

Alternatively, the number of the accommodating holes is several, one part of the accommodating holes has one end leading to the side outer surface of the reinforcing structure, and the rest of the accommodating holes have a bottom leading to the reinforcing structure one end of the outer surface.

In this solution, the above two forms of installation structures can realize the connection of the quick-change unit or the battery pack fixing unit from the side by cooperating with the connecting piece and the locking piece, or realize the connection of the quick-change unit or the battery pack fixing unit from the side and bottom. Connection of the battery pack holding unit. When the quick-change unit or the battery pack fixing unit is connected to the battery box through the structure of the L-shaped plate, the two parts of the L-shaped plate and the side and bottom of the reinforced structure can be connected through the above two parts by using the connecting piece and the locking piece. Various forms of installation structures are fixedly connected, which can play a more stable role in the connection. 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.

Preferably, 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.

In this scheme, the screw connecting piece and the nut locking piece are adopted, the structure is simple, and the connection is convenient and reliable. The screw connection can be a connection with a screw such as a bolt, a screw, or the like. Nut locking parts include common nuts such as hexagonal nuts and square nuts, or special nuts such as expansion nuts.

Preferably, at least a part of the inner surface of the accommodating hole in the axial direction is used as a placement groove for installing the locking member.

In this solution, part or all of the inner surface of the accommodating hole along its axial direction is used as a placement groove, and the locking member (the nut locking member is preferably an expansion nut) is placed in it, and the inner surface of the accommodating hole is passed through The way of expansion or embedding is pressed and fixed with the accommodating hole, the installation is fast and convenient, and the connection structure is simplified.

Preferably, the placing groove is co-formed with the reinforcement structure through the pre-set locking part, so as to fix the pre-set locking part.

In this solution, the above-mentioned structure is adopted. When the nut is made into the lower box, the pre-embedded nut is pre-embedded in the lower box, and at the same time, the placement cavity covering the nut is formed. When in use, it can be directly connected to the embedded nut through bolts, reducing the setting of moving parts and facilitating disassembly and assembly.

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 member in the placement groove, and the placement groove has a The moving space for the locking member to move in a direction perpendicular to the connection direction of the locking member and the connecting member.

In this solution, a placement slot with a placement opening is used, and a locking piece with a certain degree of freedom of movement is placed in the placement slot. Since the locking piece is installed after the lower box is made, and the locking piece can be accommodated There is a certain degree of freedom of movement in the cavity, which is convenient for assembly, reduces the requirements for the machining accuracy of the lower box, and can avoid possible damage to the surface of the forming mold caused by the pre-embedded locking parts.

Preferably, the top surface of the reinforcement structure is provided with a sealing groove, 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 In the sealed groove.

In this solution, the above structural form is adopted, and the quick change unit can be fixed on the reinforcement structure from the side by using the locking member. This structural form is convenient for installing the locking member at a deeper position in the reinforcement structure without greatly affecting the structure of the lower box body, and the locking member is not exposed, which improves reliability.

Preferably, the groove bottom of the sealing groove is provided with several reinforcement ribs in the groove, the length direction of the reinforcement ribs in the groove is perpendicular to the length direction of the sealing groove, and the placement opening of the placement groove is arranged on the sealing surface. At the bottom of the groove between two adjacent reinforcement ribs in the groove, the number of placement openings between adjacent reinforcement ribs in the groove is not more than two.

Preferably, the reinforcement structure has two arms opposite to each other, and the ends of the arms have inwardly turned snap-fit parts, the arms and the snap-fit parts form the placement groove, and The placing groove has a lateral opening leading to the outer surface of the reinforcing structure, and the lateral opening is used to form the placing opening.

In this solution, the placement slots of the above-mentioned structural form are arranged in the reinforcement structure, and the placement slots are set in the above-mentioned space, without additional holes or slots, so as to improve economic benefits and facilitate installation.

Preferably, the placing groove is provided with restraining ribs for restricting the movement of the locking member before the connecting member is connected with the locking member, and the restraining ribs are formed on two opposite side walls in the placing groove, and are connected with The locking parts abut against each other, and the width of the restraining rib gradually decreases from the side wall where it is located to the locking part.

In this scheme, the restraining ribs can preliminarily restrain and position the nuts placed in the placement groove, and can prevent the nuts placed from falling out. The tapering structure from the side wall to the locking part allows a small amount of movement during the tightening process of the nut, so as to realize the movement of the nut.

Preferably, the lower box body further includes a connecting plate, the connecting plate is connected to the installation structure through a connecting mechanism, the connecting plate is fixed on the side of the lower box body, and the connecting plate is used for connecting the quick change unit or battery pack fixing unit.

In this solution, by setting the connecting plate on the reinforced structure, and setting the quick-change unit or battery pack fixing unit on the connecting plate, the detachable and quick connection between the battery pack and the electric vehicle or the fixed connection with the electric vehicle can be realized. 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.

The connection mechanism is installed through the installation structure, and the quick-change unit of the battery pack can be fixed on the lower box to facilitate the detachable connection of the battery pack containing the lower box to the electric vehicle, or the battery pack fixing unit can be fixed on the lower box. Therefore, it is convenient for the battery containing the lower box to be fixedly connected to the electric vehicle, and the lower box is made of non-metallic composite material, which can reduce weight compared with a metal shell and has good heat preservation effect.

Preferably, the connecting plate is an L-shaped connecting plate, and the L-shaped connecting plate has a longitudinal connecting portion and a transverse connecting portion perpendicular to each other, the longitudinal connecting portion is connected to the side of the reinforcement structure, and the transverse connecting portion The connection part is connected with the bottom surface of the reinforcement structure.

In this solution, the above-mentioned structural form is adopted, and the L-shaped connecting plate can be connected with the reinforcement structure from two directions, thereby improving the connection and fixing effect.

Preferably, the bottom surface of the lower box body is provided with a concave surface, and the concave surface is used for installing the transverse connection part.

In this solution, a stepped surface is formed between the recessed surface and 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 guaranteed to be flat .

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

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

Preferably, the lower box further includes an inner shell, the inner shell is stacked in the lower box, a reinforcing rib is provided between the inner shell and the lower box, and the A chamber structure is formed between the inner casing and the lower box.

In this solution, the above structural form is adopted, since the inner shell is stacked in the lower box to form a composite structure, which further strengthens the strength of the lower box and improves the heat preservation effect of the battery at the same time. In addition, reinforcing ribs are provided between the inner casing and the lower box, so that the structure of the lower box is strengthened, meeting the strength requirements of the battery box. At the same time, the chamber structure improves the heat insulation effect of the lower box.

A battery pack, which includes an upper cover, a battery unit, a battery pack connection unit, and the lower box body of the above-mentioned battery box, the lower box body has an accommodating cavity with an open upper end, the battery unit is installed in the accommodating cavity, The upper cover is arranged on the lower box and closes the accommodating cavity, the battery pack connecting unit is fixed on the reinforcement structure, and the battery pack connecting unit includes a quick change unit and a battery pack fixing unit .

In this solution, the battery pack seals the battery unit (directly composed of multiple batteries to form a module-free form, or composed of multiple battery modules composed of batteries) in the box surrounded by the upper cover and the lower box. In the accommodating cavity, a protective barrier is formed for the battery unit and has a thermal insulation effect. Moreover, the lower case of the battery pack is made of non-metallic composite material, which can reduce the weight compared with the metal case, and further improve the heat preservation effect and economic benefits.

Among them, the quick change unit includes but is not limited to: electric/liquid cooling connector, locking mechanism, etc., and the locking mechanism includes a threaded locking mechanism (a locking mechanism that fixes the battery box and the vehicle body through multiple bolts), locking pins, etc. Locking mechanism (a locking mechanism that fixes the battery box to the vehicle body by locking pins), a rotation locking mechanism (a locking mechanism that fixes the battery box to the vehicle body by rotating and locking), and a flipping locking mechanism (The locking mechanism that fixes the battery box and the vehicle body by flipping and locking), the pressing locking mechanism (the locking mechanism that fixes the battery box and the vehicle body by pressing the locking method), the staggered tooth locking mechanism ( The locking mechanism that fixes the battery box and the vehicle body through the staggered locking method), the latch locking mechanism (the locking mechanism that fixes the battery box and the vehicle body through the latch locking method), the push-pull locking mechanism (the The locking mechanism that fixes the battery box and the vehicle body by way of locking).

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 connections, etc.). An electric vehicle, the electric vehicle includes the above-mentioned battery pack.

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 is detachably connected to the vehicle body, enabling rapid separation of vehicle and electricity), rechargeable electric vehicles ( The battery pack is fixed on the body, and the charging on the body is used as the main means of supplementing energy), electric vehicles with quick change and charging functions and other types of electric vehicles.

On the basis of conforming to common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain preferred examples of the present invention.

The positive progress effect of the present invention is that: the lower box body is made of non-metallic composite material, and compared with the lower box body made of metal, it has better heat preservation effect, is more suitable for use in cold regions, and is lighter in weight. The lower box extends the side wall outwards to form a reinforcement structure, which enhances the strength of the side wall, facilitates the installation structure on the reinforcement structure, and further facilitates the installation of the connection mechanism for the connection of battery pack accessories.

Description of drawings

FIG. 1 is a schematic structural view of the lower box of the battery box hiding the inner casing in Embodiment 1. FIG.

Fig. 2 is a schematic diagram of the local structure of the sealing groove of the lower box body of the battery box in Example 1.

FIG. 3 is a schematic structural view of a placement groove of the lower box body of the battery box in Example 1. FIG.

FIG. 4 is a structural schematic diagram of another slot for hiding the locking element in Embodiment 1. FIG.

FIG. 5 is a schematic structural view of the battery box of Example 1. FIG.

FIG. 6 is a partial cross-sectional structural schematic view of the battery box of Example 1. FIG.

FIG. 7 is an enlarged view of an accommodating hole of the lower box body of the battery box in Embodiment 2. FIG.

Fig. 8 is a schematic diagram of the exploded structure of the upper case cover of the battery case of the test example.

Explanation of reference signs:

Lower box 1

base plate 11

side wall 12

Strengthening Structures 121

The first strengthening part 1211

The second reinforcement part 1212

Seal groove 1213

Accommodating hole 1214

Place slot 1215

Constraint Rib 12151

External ribs 1216

Internal ribs 1217

Reinforcing ribs in groove 1218

arm 122

Clamping part 123

concave surface 13

Gluing tank 14

inner shell 15

Connector 101

Locking piece 102

connection plate 2

longitudinal connection 21

Transverse connection 22

Cover 3

battery box 10

Cover shell 11a

Insulation layer 12a

protective layer 13a

Detailed ways

The present invention is further illustrated below by means of examples, but the present invention is not limited to the scope of the examples.

Example 1

As shown in FIGS. 1-6 , this embodiment discloses a lower box body of a battery box for forming 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 reinforcement structure 121 is provided on the outer peripheral surface of the side wall 12. The side wall 12 is extended outward to form a reinforcement structure 121 to enhance the strength of the side wall 12. It is convenient to install an installation structure on the reinforcing structure 121 , and it is further convenient to install a connection mechanism for the connection of battery pack accessories (such as a quick change unit or a battery pack fixing unit). When the quick-change unit is installed in the installation structure, it is mainly connected to the bottom of the battery pack and the electric vehicle, so as to facilitate the battery exchange operation of the electric vehicle. When the installation structure installs the battery pack fixing unit, it is mainly used to fix the battery pack on the electric vehicle without disassembly.

The lower box body 1 is made of 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 in weight.

More specifically:

Further, in this embodiment, the material of the lower box is SMC (Sheet molding compound), which is lighter in weight and better in heat preservation.

As shown in Figures 1 and 4, further, in this embodiment, the reinforcing structure 121 includes a first reinforcing part 1211, a second reinforcing part 1212 and several external reinforcing ribs 1216, and the first reinforcing part 1211 and the second reinforcing part 1212 are spaced up and down around the side wall 12 , and a plurality of external reinforcing ribs 1216 are spaced between the first reinforcing part 1211 and the second reinforcing part 1212 along the circumferential direction of the side wall 12 . The first reinforcement part 1211 and the second reinforcement part 1212 reinforce the strength of the side wall 12 of the lower case 1 in the circumferential direction. The external reinforcing rib 1216 is disposed between the first reinforcing part 1211 and the second reinforcing part 1212 to strengthen the strength of the side wall 12 in the vertical direction. The structural forms of the first reinforcement part 1211, the second reinforcement part 1212 and several external reinforcement ribs 1216 enhance the strength of the side wall 12 of the lower box body 1 in the circumferential and vertical directions, and are beneficial to the structure of the lower box body 1. lightweight. Further, in this embodiment, the first reinforcement part 1211 and the second reinforcement part 1212 are plate-like structures extending horizontally outwards, the thickness of the first reinforcement part 1211 is greater than the thickness of the second reinforcement part 1212, and the side direction of the lower box body The connecting mechanism is mainly arranged on the first reinforcement part 1211 or on the solid structure relying on the first reinforcement part 1211 .

As shown in FIG. 1 , several external reinforcing ribs 1216 divide the space between the first reinforcing part 1211 and the second reinforcing part 1212 into multiple regions, which helps to improve the thermal insulation performance of the lower box body 1 . Further, in this embodiment, each region is generally in the shape of a cuboid.

As shown in FIG. 1 , in this embodiment, internal reinforcing ribs 1217 are arranged in a staggered manner on the inner surface of the bottom plate 11 and the inner surface of the side wall 12 . The overall strength of the lower box body 1 is improved by using the internal reinforcement ribs 1217 and the peripheral reinforcement structure 121 on the inside of the lower box body 1, and it is also convenient to form a cavity between the internal reinforcement ribs 1217 and in the frame of the reinforcement structure 121, which is more convenient. Insulation materials can be placed in the cavity to improve the insulation effect of the lower box body 1 . Furthermore, the internal reinforcing ribs 1217 are arranged vertically and horizontally on the bottom of the lower box, and only vertical reinforcing ribs are provided on the side of the lower box.

As shown in Figure 1, further, in this embodiment, some external reinforcement ribs 1216 are arranged at positions corresponding to the internal reinforcement ribs 1217, so as to form a corresponding reinforcement structure inside and outside the lower box body 1, and lift the lower box body. Body 1 overall strength.

Further, in this embodiment, the reinforcing structure 121 is provided with several mounting structures for mounting the connecting mechanism.

Further, as shown in FIG. 1 and FIG. 3 , the installation structure includes an accommodating hole 1214 and a placement groove 1215 arranged in the reinforcing structure 121, the accommodating hole 1214 communicates with the placement groove 1215, and the accommodating hole 1214 has a One end of the outer surface of the reinforcement structure 121; the accommodating hole 1214 and the placement groove 1215 are respectively used to install the connecting piece 101 and the locking piece 102 constituting the connecting mechanism, so that the connecting piece 101 passes through the accommodating hole 1214 and is located in the placing groove 1215 The locking elements 102 are connected. The number of accommodating holes 1214 is several, and each accommodating hole 1214 has one end leading to the side outer surface of the reinforcement structure 121, and the connecting member 101 is connected to the locking member 102 in the placement groove 1215 through the accommodating holes 1214 .

Furthermore, in this embodiment, the number of accommodating holes is several, some of the accommodating holes have one end leading to the side outer surface of the reinforcing structure, and the rest of the accommodating holes have a bottom outer surface leading to the reinforcing structure one end. The installation structure, by cooperating with the connecting piece and the locking piece, can simultaneously connect the quick change unit from the side and the bottom. When the quick-change unit is connected to the battery box through the structural parts of the L-shaped plate, the longitudinal connection plate (attached to the side surface of the reinforcement structure) and the bottom extension plate (towards the Turn down and surround the bottom edge of the lower box) and the two parts are respectively fixedly connected with the side and the bottom of the reinforcement structure through the above two forms of installation structures, which can play a role of more stable connection. Moreover, the above two types of connecting parts are perpendicular to each other, which can fix the quick change unit from two directions, and the reliability is higher.

As shown in FIG. 2 , FIG. 4 and FIG. 6 , the connecting piece 101 includes a screw connecting piece, and the locking piece 102 includes a nut locking piece, which is used for threaded connection with the screw connecting piece. In this embodiment, a screw connecting piece and a nut locking piece are used, which have a simple structure, convenient and reliable connection. Furthermore, the screw connection part adopts a connection part 101 with a screw such as a bolt or a screw. The nut locking part adopts a square nut. The square nut can avoid rotation in the placement groove 1215 after the nut connector is put into the placement groove 1215 to the greatest extent.

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 made, and locked The parts can have a certain degree of freedom of movement in the accommodating cavity, and the assembly is convenient, which reduces the requirement on the processing accuracy of the lower box body 1, and can avoid damage to the surface of the forming mold that may be caused by the pre-embedded locking parts.

Further, in this embodiment, one end of the accommodating hole 1214 of the mounting structure used for fixedly connecting the quick change unit from the side leads to the side outer surface of the reinforcement structure. Further, as shown in FIG. 4 , It is arranged at the position where the first extension 1211 intersects with the external reinforcing rib 1216, and a thickened structure is provided at the position of the part exposed in the area separated by the external reinforcing rib 1216, so as to increase the strength of the connection. In this case, the placement groove 1215 of the above-mentioned installation structure extends downward from the top of the reinforcement structure to communicate with the other end of the accommodation hole 1214 . The quick change unit can be fixed on the reinforcing structure 121 from the side by using the locking piece.

As shown in Figure 1, Figure 2 and Figure 3, further, in this embodiment, the top surface of the reinforcing structure 121 is provided with a sealing groove 1213, and the sealing groove 1213 is used to embed the upper cover 3 of the battery box 10 with the lower The sealing strip for sealing the box body 1, the placement opening of the placement groove 1215 is located in the sealing groove 1213 . This structural form is convenient for installing the locking member at a deeper position in the reinforcing structure 121 without greatly affecting the structure of the lower box body 1 , and the locking member 102 is not exposed, which improves reliability.

As shown in Figure 2, further, the groove bottom of the sealing groove 1213 is provided with a number of ribs 1218 in the groove. Seal the bottom of the groove between the reinforcing ribs 1218 in two adjacent grooves in the sealing groove 1213, and the number of placing openings between the reinforcing ribs 1218 in adjacent grooves is not more than two, so as to avoid setting too many placing openings, which will affect the structure of the reinforcement. strength.

In this embodiment, FIG. 4 shows another form of placement groove 1215 , in order to show the structure of the placement groove 1215 , the nut locking part 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, and the placement opening is used to place the locking member (not shown in the figure) in the placement groove 1215. There is an active space for movement in the direction of the connection direction of the locking member and the connecting member 101 . The quick change unit can be fixed on the reinforcing structure 121 from the side by using the locking piece. Furthermore, the reinforcing structure 121 has two arms 122 opposite to each other. The end of the arms 122 has an inwardly turned engaging portion 123. The arm 122 and the engaging portion 123 form a placement groove 1215. The placement groove 1215 has a through The side opening to the outer surface of the reinforcing structure 121 is used to form a placement opening. The placing groove 1215 is arranged in the reinforcement structure 121, and no additional holes or grooves are required, which is convenient for installation.

As shown in Fig. 3 and Fig. 4, the two kinds of placement grooves 1215 are provided with restraining ribs 12151 for restricting the movement of the locking member 102 before the connecting member 101 and the locking member 102 are connected. On two opposite side walls 12, and abut against the locking piece 102, and the width of the restraining rib 12151 gradually decreases from the side wall 12 where it is located to the locking piece 102. The restraining ribs 12151 can preliminarily restrain and position the nuts placed in the placement groove 1215, and can prevent the nuts placed from falling out. The tapering structure from the side wall to the locking member 102 is adopted to allow a small amount of displacement of the nut during the tightening process, so as to realize the movement of the nut.

As shown in FIG. 6 , the lower box body 1 also includes a connecting plate 2 connected to the installation structure through a connecting mechanism, the connecting plate 2 is fixed on the side of the lower box body 1, and the connecting plate 2 is used for connecting the quick change unit. In this embodiment, by setting the connecting plate 2 on the reinforcing structure 121 and setting 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 setting of the connecting plate 2 makes the battery pack When the quick-change unit is connected to the electric vehicle, the force is more balanced and the connection is more stable. The connection mechanism is installed through the installation structure, and the quick-change unit of the battery pack can be fixed on the lower box body 1, so that the battery pack containing the lower box body 1 can be detachably connected to the electric vehicle, so as to facilitate the battery containing the lower box body 1 It is fixedly connected to the electric vehicle, and the lower box body 1 is made of non-metal composite material, which can reduce weight compared with the metal shell and has good heat preservation effect.

As shown in Figure 6, 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 perpendicular to each other, and the longitudinal connecting portion 21 and the reinforcement The side surfaces of the structure 121 are connected, and the transverse connecting portion 22 is connected with 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, so as to improve the connection and fixing effect.

Furthermore, in this embodiment, the bottom surface of the lower box body 1 is provided with a concave surface 13 , which forms a stepped surface with other parts of the bottom plate 11 , and the concave surface 13 is used for installing 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 more flat.

Further, the side surface and the bottom surface of the reinforcement structure 121 are provided with a glue groove 14, the glue groove 14 is used for glue application, so as to bond and fix the connection plate 2, and strengthen the connection and fixation between the connection plate 2 and the reinforcement structure 121 effect, and easy to install.

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

This embodiment also discloses a battery pack, which includes an upper cover 3, a battery unit, a battery pack connection unit, and the lower box body 1 of the above-mentioned battery box. The lower box body 1 has an accommodating chamber with an open upper end, and the battery unit is installed The accommodating cavity, the upper cover 3 is set on the lower box body 1 to close 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 seals the battery unit (composed of a plurality of battery modules composed of batteries) in the accommodation chamber surrounded by the upper cover 3 and the lower box 1, forming a protective barrier for the battery unit and It has thermal insulation effect. Moreover, the lower case 1 of the battery pack is made of non-metallic composite material, which can reduce the weight compared with the case made of metal, and further improve the heat preservation effect and economic benefits.

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

Example 2

As shown in Figure 7, this embodiment is basically the same as Embodiment 1, the difference is that in this embodiment, at least a part of the inner surface of the accommodating hole 1214 in its axial direction is used as a placement groove 1215 (i.e. placement groove 1215 is a part of the accommodation hole 1214 ), for installing the locking member 102 . In this embodiment, part of the inner surface of the accommodating hole 1214 along its axial direction is used as a placement groove 1215, and the locking member 102 is placed therein. The locking member 102 is preferably an expansion nut in this embodiment. The accommodating hole 1214 is compressed and fixed with the accommodating hole 1214 by means of expansion or embedding, so that the installation is fast and convenient, and the connection structure is simplified. However, compared with the setting method of the installation structure in embodiment 1, the setting method of the installation structure in embodiment 2 will be more cumbersome in the installation process of the locking member 102, and the expansion nut is usually heavier than the square nut in weight .

Example 3

The placement groove can be co-formed with the reinforcement structure through the pre-set locking part, and is used for fixing the pre-set locking part. When the nut is made into the lower box, the embedded nut is pre-embedded in the lower box by means of pre-embedding, and at the same time, the placement cavity covering the nut is formed. When in use, it can be directly connected to the embedded nut through bolts, reducing the setting of moving parts and facilitating disassembly and assembly. However, the fixing form of this installation structure requires relatively high machining accuracy of the lower box body, and the prefabricated nuts are easy to cause damage to the molding die of the lower box body.

In addition to the above embodiments, in other embodiments it is also possible to:

The area formed by the space between the first reinforcing part 1211 and the second reinforcing part 1212 separated by the outer reinforcing rib 1216 may be filled with a lightweight thermal insulation material.

The aforementioned lightweight thermal insulation materials include, but are not limited to: polymer foam materials, airgel felts, and the like. Polymer foaming material refers to a microporous material with numerous bubbles inside it based on polymer (plastic, rubber, elastomer or natural polymer material). Typical polymer foaming materials such as polyurethane (Polyurethane) foam, Polystyrene foam, etc. Preferably, the above-mentioned light-weight insulation material adopts airgel felt.

The inner side surface of the bottom plate and/or the inner side surface of the side wall may be provided with internal reinforcing ribs arranged at intervals or in a staggered manner. 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, so as to realize the reinforcement of the bottom plate and the side wall of the lower box.

The inner casing may not be provided inside the lower box. In the case of setting the inner casing, the chamber for placing the battery can be made more regular, and the strength of the lower box can also be improved to a certain extent.

The accommodating hole 1214 may have only one end leading to the side outer surface or the bottom outer surface of the reinforcement structure 121 . When the accommodating hole 1214 has only one end leading to the side outer surface of the reinforcement structure 121 , the connection to the quick change unit or the battery pack fixing unit can be realized from the side. When the accommodating hole 1214 has only one end leading to the bottom outer surface of the reinforcement structure 121 , the connection to the quick change unit or the battery pack fixing unit can be realized from the bottom surface.

The connection plate used to realize the connection between the quick change unit or the battery pack fixing unit and the lower case may also only have a longitudinal connection plate, or only have a bottom extension plate. In the case that the connecting plate is an L-shaped plate, the longitudinal connecting plate and the bottom extension plate may present other included angles.

The screw connecting piece of the connecting piece 101 may also be a connecting piece with a screw such as a screw, and the nut locking piece may also be a hex nut, an expansion nut, or the like.

The groove bottom of the sealing groove 1213 may also not be provided with the reinforcing rib 1218 in the groove.

Glue grooves may be provided on the side surfaces or the bottom surface of the reinforcing structure.

There may be a circular avoidance hole matched with the lock shaft of the quick change unit in the area formed by the outer rib 1216, and the avoidance hole at least connects the first connection part and the second connection part.

The reinforcement structure 121 of the lower box can also be equipped with quick-change units of other structures, or with battery pack fixing units. The quick-change units of other structures are used for detachable connection with electric vehicles, and the battery pack fixing units are used for connecting with electric vehicles Car fixed connection. Among them, other quick-change units include, but are not limited to: electrical/liquid cooling connectors, locking mechanisms (battery pack ends), etc. Electric/liquid cooling connectors include electrical connectors and/or liquid cooling connectors. Electrical connectors are used for electrical connection with electric vehicles. Liquid cooling connectors are mainly used as liquid cooling mechanisms when using liquid cooling mechanisms inside the battery pack. The interface between the cold mechanism and the electric vehicle cools the battery pack and improves safety. The locking mechanism (battery pack side) includes a threaded locking mechanism (a locking mechanism that fixes the battery box to the vehicle body through multiple bolts), a lock pin locking mechanism (a locking mechanism that fixes the battery box to the vehicle body by locking pins) locking mechanism), rotation locking mechanism (locking mechanism that fixes the battery box and the body by rotating and locking), flipping locking mechanism (locking mechanism that fixes the battery ), top pressure locking mechanism (the locking mechanism that fixes the battery box and the vehicle body by the top pressure locking method), other types of staggered tooth locking mechanism (the battery box and the vehicle body are fixed by the staggered tooth locking method) locking mechanism), latch locking mechanism (a locking mechanism that fixes the battery box and the vehicle body by a latch locking method), push-pull locking mechanism (a locking mechanism that fixes the battery box and the vehicle body by a push-pull locking method) Wait for the locking mechanism that is arranged on the battery pack end (relative to the car end). The fixing unit includes a bolt-type locking mechanism or other types of fixed connection mechanisms (including but not limited to mechanical, electrical or magnetic connections, etc.) and the like.

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 Body, with charging on the body as the main means of energy supplement), electric vehicles with quick change and charging functions and other types of electric vehicles.

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

Test case

A quick-change electric vehicle currently uses sheet metal battery packs (using mica sheets as insulation materials), and its weight is 371.5kg. Prepare non-metallic composite material battery packs with the same size specifications (external dimensions and internal space dimensions of the battery box).

Utilize the non-metallic composite material lower casing in embodiment 1, the height of the chamber structure between the lower casing and the inner casing (that is, the distance between the opposite surfaces of the lower casing and the inner casing) is 5mm, when The lower box formed when no airgel is placed in the chamber structure is recorded as the lower box of non-metallic composite material, and the lower box formed when airgel is placed in the chamber structure is recorded as the lower box of non-metallic composite material B. The lower box body A of the non-metallic composite material and the lower box body B of the non-metallic composite material are respectively combined with the upper box cover by means of buckle fastening to form a non-metallic composite material battery box (see Figure 5), respectively recorded as The non-metal composite battery box A and the non-metal composite battery box B are respectively loaded with battery modules and necessary electrical components to form a non-metal composite battery pack A and a non-metal composite battery pack B.

As shown in Figure 8, the upper cover 3 of the non-metallic composite material used to form the non-metallic composite material battery box with the non-metallic composite material lower box body A and the non-metallic composite material lower box body B respectively includes: the box cover shell 11a, heat insulating layer 12a and protective layer 13a. The heat insulation layer 12a and the protective layer 13a are sequentially covered and fixed on the side of the box cover shell 11a facing the lower box body. The material of the box cover shell 11a is SMC, the material of the heat insulation layer 12a is airgel felt with a thickness of 5mm, and the protective layer The material of 13a is fireproof cloth, and the connection between the cover shell 11a and the heat insulation layer 12a and between the heat insulation layer 12a and the protective layer 13a are all connected by structural adhesive, and a concave-convex structure is set on the box cover shell 11a In order to increase the strength, the upper cover 3 and the lower box are sealed in a U-shaped seal, and the side of the upper cover 3 is provided with a concave part, which cooperates with the raised part arranged on the side of the lower box to form a snap connection ( U-shaped seal and buckle connection as shown in Figure 6), the upper cover 3 and the lower box cover are molded once to realize the fastening of the buckle connection structure.

Test the non-metallic composite material battery pack A, non-metallic composite material battery pack B and sheet metal battery pack of the same size and specification.

In terms of weight test, the mass of the non-metallic composite lower box B is 45kg, while the sheet metal lower box (using mica sheet as insulation material) of the same size and specification has a mass of 60.4kg. Compared with the lower box made of sheet metal, the lower box B made of non-metallic composite material has a weight reduction of 25.5%. The weight of the battery box B made of non-metallic composite material is 57.8kg, and the weight of the battery box made of sheet metal is 70.772kg. The weight advantage of the battery box made of non-metallic composite material is obvious. Compared with the lower box B of non-metallic composite material, the lower box A of non-metallic composite material lacks the airgel felt placed in the chamber structure. Due to the lower density of the airgel felt, the amount of use is not large , therefore, the quality of the non-metallic composite lower box A is equivalent to that of the non-metallic composite lower box B, with a slight decrease (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 2-3% less than that of the sheet metal battery pack, and the weight advantage is obvious.

In terms of strength testing, the non-metallic composite material lower box A and the non-metallic composite material lower box B, and the non-metallic composite material upper cover used to form a composite non-metallic battery box with the two all meet GB/T 31467.3- 2015 "Lithium-ion Traction Battery Packs and Systems for Electric Vehicles Part 3: Safety Requirements and Test Methods" stipulates the strength and other requirements (the actual test can reach 1.5 times the standard). Can be used in electric vehicles.

In terms of thermal insulation performance and heat insulation performance: the initial temperature in the package is 20-30°C, and it is placed in an environment of 7-9°C for 600 minutes, the accumulative temperature change rate of the cells in the pack of non-metallic composite battery pack A (The accumulative cooling rate) is lower than 50% of the battery pack made of sheet metal (the temperature of the single cell is measured by optical fiber), and the accumulative temperature change rate of the single cell in the non-metallic composite battery pack B is only the sheet metal battery pack. About 40% of the battery pack is made of gold material. This advantage is more obvious at lower temperatures, and it can ensure that the temperature of the battery core is at a better operating temperature when used in cold northern regions. Moreover, after testing, the non-metallic composite material battery pack A and the non-metallic composite material battery pack B can withstand a high temperature of 1000°C. In the test of simulating a battery fire, even if the battery is completely burned, the non-metallic composite material box is basically in the whole test process. In good condition with only smoke and no open flames.

The cell placement cavity of non-metallic composite battery pack A and non-metallic composite battery pack B is filled with thermally conductive glue (the filling height of thermally conductive glue is about 1/3 of the height of the battery), so as to increase the temperature uniformity between the cells , to avoid thermal runaway caused by abnormal temperature of individual cells. Secondly, the battery cells (or battery modules formed by the battery cells) inside the battery box are formed as a whole, which increases the overall strength of the battery pack. Comparing the non-metallic composite battery pack B in the above case with the above-mentioned sheet metal battery pack, in the same environment, when charging with a charging current of 40A (SOC from 0-100%), the sheet metal battery pack is faster than the non-metallic battery pack. The accumulative temperature rise of metal composite battery pack B is more than 5°C, the charging capacity of non-metallic composite battery pack B is more than 5% higher than that of sheet metal battery packs, and the maximum temperature difference inside the box of composite non-metallic battery packs ( Obtained by recording all positive and negative lug temperatures) Uniformity maintained at 1.5-2°C. This is not only related to the use of thermally conductive adhesive, but also related to the specific heat capacity and thermal insulation performance of SMC higher than that of sheet metal materials. The above factors make the non-metallic composite battery pack of this application more advantageous than sheet metal battery packs in terms of avoiding thermal runaway .

The performance of some raw materials used in the above-mentioned test examples is as follows:

SMC meets the following performance requirements: material grade (disordered glass fiber state) tensile strength ≥ 70Mpa (GB/T 1447-2005), bending strength ≥ 160MPa (GB/T 1449-2005), impact toughness ≥ 55KJ/m2 (GB /T 1451-2005), elongation at break ≥ 1.3% (GB/T 1447-2005).

Airgel felt has a density of about 0.16 mg/cm3.

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

The above-mentioned SMC, airgel felt and structural glue can be commercially available products or self-made products that meet the above performance requirements, and the rest of the materials are commercially available products.

Although the specific implementation of the present invention has been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims (20)

1. A lower box body of a battery box, which is used to form a battery pack, is characterized in that the lower box body is made of non-metallic composite material, the lower box body has a bottom plate and side walls arranged around the edge of the bottom plate, the A reinforcement structure is provided on the outer peripheral surface of the side wall, and the reinforcement structure is formed by extending the side wall outward, and several mounting structures for mounting the connection mechanism are provided on the reinforcement structure.
2. The lower box body of the battery box according to claim 1, wherein the reinforcement structure comprises a first reinforcement part, a second reinforcement part and several external reinforcement ribs, and the first reinforcement part and the second reinforcement part One above and one below surrounding the side wall, a plurality of external reinforcement ribs are arranged at intervals along the circumferential direction of the side wall between the first reinforcement part and the second reinforcement part.
3. The lower box body of the battery box according to claim 2, wherein a plurality of said external reinforcing ribs divide the space between said first reinforcing part and said second reinforcing part into a plurality of areas, and in said areas Filled with lightweight insulation.
4. The lower box body of the battery box according to at least one of claims 1-3, 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 side surface of the bottom plate and the inner side 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 at least one of claims 2-4, characterized in that at least a part of the outer reinforcement ribs are arranged at positions corresponding to the inner reinforcement ribs.
6. The lower box body of the battery box according to at least one of claims 1-5, wherein the installation structure includes an accommodating hole and a placement groove arranged in the reinforcing structure, and the accommodating hole and The placing groove is connected, and the accommodating hole has one end leading to the outer surface of the reinforcement structure; the accommodating hole and the placing groove are respectively used to install the connecting piece and the locking mechanism constituting the connecting mechanism. piece, so that the connecting piece is connected with the locking piece located in the placement groove through the accommodating hole.
7. The lower box body of the battery box according to claim 6, wherein the number of the accommodating holes is several, and each accommodating hole has an opening leading to the side outer surface of the reinforcing structure. one end;

   Alternatively, the number of the accommodating holes is several, one part of the accommodating holes has one end leading to the side outer surface of the reinforcing structure, and the rest of the accommodating holes have a bottom leading to the reinforcing structure one end of the outer surface.
8. The lower box body of the battery box according to claim 6 or 7, wherein 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 connecting with the The above-mentioned screw connection is threaded.
9. The lower box body of the battery box according to at least one of claims 6-8, characterized in that at least a part of the inner surface of the accommodating hole in the axial direction is used as a placement groove for installing the locking pieces.
10. The lower box body of the battery box according to at least one of claims 6-9, characterized in that, the placement groove is co-formed with the reinforcement structure through the preset locking piece, and is used to fix the preset locking piece .
11. The lower box body of the battery box according to at least one of claims 6-10, wherein 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 The locking piece is placed in the placement groove, and there is an activity space for the locking piece to move in a direction perpendicular to the connection direction of the locking piece and the connecting piece in the placement groove.
12. The lower box body of the battery box according to at least one of claims 6-11, wherein the top surface of the reinforcement structure is provided with a sealing groove, and the sealing groove is used to embed the upper cover of the battery box with the The sealing strip for the sealing of the lower box body, the placement opening of the placing groove is located in the sealing groove.
13. The lower box body of the battery box according to claim 12, wherein the groove bottom of the sealing groove is provided with a number of reinforcing ribs in the groove, and the length direction of the reinforcing ribs in the groove is perpendicular to the length of the sealing groove Direction, the placement opening of the placement groove is set at the bottom of the groove between two adjacent reinforcement ribs in the groove in the sealing groove, and the number of placement openings between the reinforcement ribs in the adjacent grooves is different. greater than two.
14. The lower box body of the battery box according to at least one of claims 11-13, characterized in that, there are two arms opposite to each other in the reinforcement structure, and the ends of the arms have inward-turned snap joints. part, the arm and the engaging part form the placement groove, the placement groove has a side opening leading to the outer surface of the reinforcement structure, and the side opening is used to form the placement opening.
15. The lower box body of the battery box according to claim 11 or 14, wherein the placement groove is provided with a restraint rib for restricting the movement of the locking member before the connecting member is connected to the locking member, and the restraining rib The ribs are formed on two opposite side walls in the placement groove and abut against the locking piece, and the width of the restraining ribs gradually decreases from the side walls where they are located to the locking piece.
16. The lower box body of the battery box according to at least one of claims 1-15, wherein the lower box body further includes a connecting plate, the connecting plate is connected to the installation structure through a connecting mechanism, and the connecting plate fixed on the side of the lower box, the connecting plate is used to connect the quick change unit or the battery pack fixing unit;

    Preferably, the connecting plate is an L-shaped connecting plate, and the L-shaped connecting plate has a longitudinal connecting portion and a transverse connecting portion perpendicular to each other, the longitudinal connecting portion is connected to the side of the reinforcement structure, and the transverse connecting portion The part is connected with the bottom surface of the reinforcement structure.
17. The lower box body of the battery box according to claim 16, wherein the bottom surface of the lower box body is provided with a concave surface, and the concave surface is used for installing the transverse connection part;

    And/or, 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 glue coating, so as to bond and fix the connecting plate.
18. The lower box body of the battery box according to at least one of claims 1-17, wherein the lower box body further comprises an inner casing, and the inner casing is stacked in the lower box body, so that A reinforcing rib is provided between the inner shell and the lower box, and a chamber structure is formed between the inner shell and the lower box.
19. A battery pack, characterized in that it comprises an upper cover, a battery unit, a battery pack connection unit, and a lower box body of the battery box according to any one of claims 1-18, the lower box body has an upper end opening The accommodating cavity, the battery unit is installed in the accommodating cavity, the upper cover is set on the lower box and closes the accommodating cavity, the battery pack connection unit is fixed on the reinforcing structure, The battery pack connection unit includes a quick change unit and a battery pack fixing unit.
20. An electric vehicle, characterized in that the electric vehicle comprises the battery pack according to claim 19.

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