Power battery box and lower box body thereof

Abstract

The utility model discloses a power battery box and a lower box body of the power battery box, the lower box body comprises a frame and a bottom plate, the bottom plate is connected with the frame, the frame comprises a front cross beam and a rear cross beam which are oppositely arranged in the front-back direction, and the front cross beam and the rear cross beam are both formed through a casting process; the two side longitudinal beams are oppositely arranged in the left-right direction, the two side longitudinal beams are located between the front cross beam and the rear cross beam, the two ends of the two side longitudinal beams are connected with the front cross beam and the rear cross beam respectively, and the two side longitudinal beams are profiles formed through extrusion; the middle longitudinal beam is located between the two side longitudinal beams and between the front cross beam and the rear cross beam, the two ends of the middle longitudinal beam are connected with the front cross beam and the rear cross beam respectively, and the middle longitudinal beam is also made of an extruded profile. According to the embodiment of the utility model, the manufacturing process is reasonably selected according to the characteristics, the mounting positions and the like of each beam in the lower box body, so that the processing is convenient, the number of parts is reduced, and the strength requirement can be ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of power batteries, in particular to a power battery box and a lower box body of the power battery box. Background Art

[0002] The lower box of the power battery box is an important carrier of the power battery. It is mainly used to carry the battery cells and other components in the battery pack, and can also play a mechanical protection function.

[0003] At present, the mainstream manufacturing processes for the lower box of power batteries mainly include profile welding, low-pressure casting and sheet metal stamping welding. However, the lower box of profile welding is limited by the extrusion process and cannot be formed into a complex structure. If it is necessary to manufacture a lower box with high and low surfaces or provide a complex installation interface, it requires additional welding parts, which has low manufacturing efficiency and is prone to aging at the connection position; although the low-pressure casting lower box can directly form a complex structure, it is limited by the casting material. The elongation of the general material is low, resulting in weak anti-collision and extrusion resistance of the product; although the lower box of sheet metal stamping welding can be formed into a complex shape, it requires multiple sheet metal sub-parts to be welded and connected, the number of sub-parts is large, the manufacturing process is many, and the sealing interface processing is difficult.

[0004] Therefore, how to provide a solution to overcome or alleviate the above-mentioned defects is still a technical problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0005] The purpose of the utility model is to provide a power battery box and a lower box body of the power battery box, which reasonably selects the manufacturing process according to the characteristics of each beam in the lower box body and the installation position, etc., which can facilitate processing to reduce the number of parts and components and ensure strength requirements.

[0006] In order to solve the above technical problems, the present invention provides a lower box body of a power battery box, including a frame and a bottom plate, the bottom plate is connected to the frame, and the frame includes: a front crossbeam and a rear crossbeam relatively arranged in the front-to-back direction, and the front crossbeam and the rear crossbeam are both formed by a casting process; two side longitudinal beams relatively arranged in the left-right direction, the two side longitudinal beams are both located between the front crossbeam and the rear crossbeam, and the two ends of the two side longitudinal beams are respectively connected to the front crossbeam and the rear crossbeam, and the two side longitudinal beams are both extruded profiles; a middle longitudinal beam is located between the two side longitudinal beams and between the front crossbeam and the rear crossbeam, the two ends of the middle longitudinal beam are respectively connected to the front crossbeam and the rear crossbeam, and the middle longitudinal beam is also an extruded profile.

[0007] In the above scheme, the front cross beam and the rear cross beam are formed by a casting process, so that complex installation interfaces can be easily formed on the front cross beam and the rear cross beam at one time. The number of parts is small, and the preparation of the front and rear cross beams can be relatively easy. At the same time, the structural design of the front and rear cross beams can be more flexible; for the side longitudinal beams and the middle longitudinal beams, there are no complex installation interface requirements. Therefore, the embodiment of the present invention chooses to adopt an extrusion process to facilitate the processing and preparation of the side longitudinal beams and the middle longitudinal beams. The extruded profile has a cavity, and its anti-extrusion performance and anti-collision performance are relatively good, which can improve the front collision and side collision resistance of the lower box to a certain extent, and can meet the strength requirements of the lower box of the power battery box.

[0008] That is to say, the embodiment of the present invention reasonably selects the manufacturing process according to the characteristics of each beam in the lower box body and the installation position, etc., which can facilitate processing to reduce the number of parts and components and ensure strength requirements.

[0009] Optionally, the side longitudinal beam includes a longitudinal beam body, the longitudinal beam body is provided with a first cavity extending in the longitudinal direction, and a first external connecting piece is sealed and assembled in the first cavity.

[0010] Optionally, the front crossbeam and the rear crossbeam are both provided with a first blocking surface, and the two first blocking surfaces are respectively sealedly connected to the two axial ends of the first cavity.

[0011] Optionally, the side longitudinal beam also includes a convex portion, which is located on the inner side of the longitudinal beam body, and the convex portion is provided with a second cavity extending in the longitudinal direction, the second cavity is isolated from the first cavity, and at least part of the two axial ends of the second cavity are offset from the first sealing surface; a first internal connecting piece is provided in the second cavity; or a first internal connecting hole is provided on the cavity wall for forming the second cavity, and the first internal connecting hole is isolated from the first cavity.

[0012] Optionally, the middle longitudinal beam is provided with a third cavity extending in the longitudinal direction, and a second external connecting piece is sealed and assembled in the third cavity.

[0013] Optionally, the front crossbeam and the rear crossbeam are both provided with a second blocking surface, and the two second blocking surfaces are respectively used for sealing connection with the two axial ports of the third cavity.

[0014] Optionally, the middle longitudinal beam is further provided with a fourth cavity extending longitudinally, the fourth cavity is isolated from the third cavity, and at least part of the two axial ends of the fourth cavity are offset from the second sealing surface; a second internal connecting piece is provided in the fourth cavity; or a second internal connecting hole is provided on the cavity wall for forming the fourth cavity, and the second internal connecting hole is isolated from the fourth cavity.

[0015] Optionally, a front end reinforcement component is further included, and the front end reinforcement component is used to connect the front cross beam and the middle longitudinal beam.

[0016] Optionally, there are multiple base plates.

[0017] The utility model also provides a power battery box, comprising a lower box body, and the lower box body is the lower box body of the power battery box mentioned above.

[0018] Since the lower box body of the power battery box mentioned above has the above technical effects, the power battery box having the lower box body should also have similar technical effects, so they will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of the lower box body of the power battery box provided by the present utility model;

[0020] Figure 2 for Figure 1 Exploded view of;

[0021] Figure 3 It is a structural diagram of the front crossbeam;

[0022] Figure 4 It is the structural diagram of the side longitudinal beam;

[0023] Figure 5 for Figure 4 Front view of

[0024] Figure 6 It is the structural diagram of the middle longitudinal beam;

[0025] Figure 7 for Figure 6 Front view of

[0026] Figure 8 This is a partial enlarged view of the connection between the front cross member and the side longitudinal member;

[0027] Figure 9 This is a partial enlarged view of the connection between the front crossbeam and the middle longitudinal beam.

[0028] The following are the descriptions of the reference numerals:

[0029] 100 frame, 110 front cross beam, 111 first blocking surface, 112 second blocking surface, 113 reinforced fixing column, 114 first fixing boss, 115 second fixing boss, 120 rear cross beam, 130 side longitudinal beam, 131 longitudinal beam body, 131a first cavity, 131b upper cover connector, 131c first bottom guard plate connector, 131d vehicle hanging connector, 131e first rib, 132 protrusion, 132a second cavity, 132b module connector, 140 middle longitudinal beam, 141 third cavity, 142 second bottom guard plate connector, 143 fourth cavity, 144 second rib, 150 front end reinforcement component, 160 fastening connector.

[0030] 200 base plate. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] In the embodiments of the present invention, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of the features.

[0033] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect" and "connect" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0034] The directional terms mentioned in the embodiments of the present invention, such as "front", "rear", "left", "right", "horizontal", "longitudinal", etc., are only referenced to the directions in the drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present invention, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present invention.

[0035] In the description of the embodiments of the present invention, the term "plurality" refers to two or more than two. Moreover, when "plurality" is used to express the number of different components, it does not indicate the relationship between the quantities of these components.

[0036] In the description of the embodiments of the present invention, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0037] Please refer to Figures 1-9 , Figure 1 This is a structural diagram of the lower box body of the power battery box provided by the utility model. Figure 2 for Figure 1 Exploded view of Figure 3 This is a structural diagram of the front crossbeam. Figure 4 The structural diagram of the side longitudinal beam is shown in Figure 2. Figure 5 for Figure 4 Front view of Figure 6 It is the structural diagram of the middle longitudinal beam. Figure 7 for Figure 6 Front view of Figure 8 This is a partial enlarged view of the connection between the front crossbeam and the side longitudinal beam. Figure 9 This is a partial enlarged view of the connection between the front crossbeam and the middle longitudinal beam.

[0038] like Figure 1 and Figure 2 As shown, the present invention provides a lower box body of a power battery box, including a frame 100 and a bottom plate 200 , wherein the bottom plate 200 and the frame 100 are connected.

[0039] The frame 100 includes a front crossbeam 110, a rear crossbeam 120, two side longitudinal beams 130, and a center longitudinal beam 140. The front crossbeam 110 and the rear crossbeam 120 are positioned opposite each other in the front-to-back direction and are both formed using a casting process. The two side longitudinal beams 130 are positioned opposite each other in the left-to-right direction and are located between the front crossbeam 110 and the rear crossbeam 120. The ends of the side longitudinal beams 130 are connected to the front crossbeam 110 and the rear crossbeam 120, respectively. Both side longitudinal beams 130 are extruded profiles. The center longitudinal beam 140 is located between the two side longitudinal beams 130 and between the front crossbeam 110 and the rear crossbeam 120. The ends of the center longitudinal beam 140 are connected to the front crossbeam 110 and the rear crossbeam 120, respectively. The center longitudinal beam 140 is also extruded profiles. In the implementation method shown in the accompanying drawings, there are two middle longitudinal beams 140, and the two middle longitudinal beams 140 can be arranged at intervals along the left and right directions; in addition, the middle longitudinal beams 140 can also be set to other numbers, for example, one or more than three, etc., which needs to be determined in combination with the dimensions of the lower box in the left and right directions.

[0040] It should be known that the front crossbeam 110 and the rear crossbeam 120 of the power battery box usually need to be installed and arranged with various parts such as water nozzles, electrical components, balancing valves, explosion-proof valves, etc. Therefore, a relatively complex installation interface needs to be designed, which is relatively difficult to process.

[0041] To address this, the present invention uses low-pressure casting or high-pressure casting to manufacture the front crossbeam 110 and the rear crossbeam 120. This allows for the convenient simultaneous formation of complex mounting interfaces on the front crossbeam 110 and the rear crossbeam 120. This reduces the number of components, making the manufacture of the front and rear crossbeams relatively easy and also allowing for greater flexibility in their structural design. For example, the front crossbeam 110 and the rear crossbeam 120 can be designed with high and low slopes, etc., depending on the intended use. The material of the front crossbeam 110 and the rear crossbeam 120 can be, for example, aluminum alloy, etc., without limitation herein.

[0042] Specifically, the front cross beam 110 can be arranged with a water faucet interface, and the upper surface plane of the front cross beam 110 can be raised as a whole so that the front cross beam 110 can participate in the force transmission of the entire vehicle collision; the rear cross beam 120 is arranged with installation interfaces for electrical connectors, balancing valves and explosion-proof valves. At the same time, the upper surface of the rear cross beam 120 can also be raised as a whole according to the layout requirements of the entire vehicle.

[0043] The side and center longitudinal beams 130 and 140 do not require complex installation interfaces. Therefore, the present embodiment utilizes an extrusion process to facilitate their fabrication. Extruded profiles have cavities, which provide superior extrusion and collision resistance. This improves the lower case's front and side impact resistance to a certain extent, meeting the strength requirements of the power battery box's lower case.

[0044] The bottom plate 200 is located at the lower side of the frame 100 and is used to block the lower end of the frame 100. The number of the bottom plate 200 can be one. Alternatively, the number of the bottom plate 200 can also be multiple; Figure 2 As shown, when the number of the center longitudinal beams 140 is two, the number of the bottom plates 200 may be three, and the three bottom plates 200 may be arranged in the left-right direction.

[0045] The bottom plate 200 and the frame 100 may be welded, for example, by friction stir welding, to ensure sealing. Alternatively, the bottom plate 200 and the frame 100 may be connected using connectors such as screws. In this case, a sealing member such as a sealing ring may be provided between the bottom plate 200 and the frame 100 to ensure sealing performance at the connection between the bottom plate 200 and the frame 100.

[0046] The structures of the front cross beam 110 and the rear cross beam 120 may be consistent.

[0047] Taking the front crossbeam 110 as an example, Figure 3 As shown, in one possible implementation, the front crossbeam 110 can be integrally formed with a first blocking surface 111, a second blocking surface 112, a reinforcing fixing column 113, a first fixing boss 114, and a second fixing boss 115, without the need for additional sub-components. This can reduce the number of components and facilitate processing. The first fixing boss 114 is a top cover fixing boss used to secure the top cover of the power battery box; the second fixing boss 115 is a bottom plate fixing boss used to secure the bottom plate 200.

[0048] like Figure 4 and Figure 5 As shown, the side longitudinal beam 130 may include a longitudinal beam body 131 . The longitudinal beam body 131 may be provided with a first cavity 131 a extending in the longitudinal direction. A first external connector is sealed and assembled in the first cavity 131 a for connecting with external parts.

[0049] Specifically, the first external connector may include an upper cover connector 131b and a first bottom guard plate connector 131c. Accordingly, the external parts may include an upper cover and a bottom guard plate. The upper cover connector 131b is used to connect the upper cover, and the first bottom guard plate connector 131c is used to connect the bottom guard plate. Both the upper cover connector 131b and the first bottom guard plate connector 131c may be sealed rivet nuts. This reduces the possibility of external moisture entering the power battery box through the mounting points of the upper cover connector 131b and the first bottom guard plate connector 131c, thereby improving sealing performance.

[0050] A plurality of first ribs 131e may also be disposed within the first cavity 131a. The first ribs 131e and the side rails 130 may be integrally formed. The first ribs 131e are used to divide the first cavity 131e into multiple sub-cavities and enhance the structural strength of the side rails 130. The upper cover connector 131b and the first bottom guard plate connector 131c may be disposed in different sub-cavities, respectively, to suit their respective installation locations.

[0051] The longitudinal beam body 131 may also be equipped with a vehicle suspension connector 131d, specifically a sleeve, which can be mounted to the longitudinal beam body 131 through a welding process and can be higher than the upper surface of the longitudinal beam body 131. This can avoid abnormal noise caused by the lower box body and the large surface of the vehicle body being attached during installation.

[0052] As previously mentioned, both the front crossbeam 110 and the rear crossbeam 120 are provided with a first blocking surface 111, and the location of the first blocking surface 111 can correspond to the first cavity 131a of the longitudinal beam body 131. During assembly, the first blocking surfaces 111 of the front crossbeam 110 and the rear crossbeam 120 can be sealed to the two axial ends of the first cavity 131a, respectively. This can form another seal. Even if the seal of the first external connection part of the aforementioned sealing arrangement fails, a second blocking seal can be provided through the first blocking surface 111, which can greatly improve the sealing performance of the lower box provided by the present invention.

[0053] The sealing method for the first sealing surface 111 to seal the axial end of the first cavity 131a is not limited herein. In practical applications, those skilled in the art may determine the method based on various factors, such as construction conditions, as long as the sealing requirements are met. For example, the first sealing surface 111 and the axial end surface of the longitudinal beam body 131 may be welded to achieve a sealed connection to the axial end of the first cavity 131a.

[0054] Furthermore, the side longitudinal beam 130 may further include a convex portion 132, which may be located inside the longitudinal beam body 131. The convex portion 132 may be provided with a second cavity 132a extending in the longitudinal direction. The second cavity 132a and the first cavity 131a may be isolated from each other. In specific applications, the second cavity 132a may be located inside the power battery box. Therefore, there is no requirement for sealing. At least part of the two axial ends of the second cavity 132a may be offset from the first sealing surface 111. For details, see Figure 8 , that is, the first blocking surface 111 may not be used to block the axial port of the second cavity 132a, and the first blocking surface 111 may be set to be relatively small, which can effectively reduce the size of the welding seal.

[0055] A first internal connector may be provided within the second cavity 132a for connecting to internal components. Specifically, the first internal connector may include a module connector 132b, which may be a battery module. The module connector 132b may be used to connect to the battery module; for example, the module connector 132b may be a rivet nut. Alternatively, a first internal connecting hole may be provided in the wall forming the second cavity 132a. The first internal connecting hole may be isolated from the first cavity 131a and may be a through hole or a blind hole, which may also be used to connect to internal components.

[0056] like Figure 6 and Figure 7As shown, the middle longitudinal beam 140 may be provided with a third cavity 141 extending in the longitudinal direction. A second external connector may be sealed and assembled in the third cavity 141 . The second external connector may also be used to connect with external parts.

[0057] Specifically, the second external connector may include a second bottom guard plate connector 142. Accordingly, the external component may include a bottom guard plate, and the second bottom guard plate connector 142 is used to connect the bottom guard plate. The second bottom guard plate connector 142 may be a rivet nut for a sealed assembly. This reduces the possibility of external moisture, etc., entering the power battery box through the mounting point of the second bottom guard plate connector 142, thereby improving the sealing performance.

[0058] As previously mentioned, the front crossbeam 110 and the rear crossbeam 120 are further provided with a second blocking surface 112, which can be positioned to correspond to the third cavity 141 of the center longitudinal beam 140. During assembly, the second blocking surfaces 112 of the front crossbeam 110 and the rear crossbeam 120 can be sealed to the two axial ends of the third cavity 141, respectively. This creates another seal. Even if the seal of the second external connection member of the aforementioned sealing arrangement fails, a secondary sealing can be achieved through the second blocking surface 112, thereby significantly improving the sealing performance of the lower box provided by the present invention.

[0059] The sealing connection method for the second sealing surface 112 to the axial end of the third cavity 141 is not limited herein. In practical applications, those skilled in the art may determine the method based on various factors such as construction conditions, as long as the sealing requirements are met. For example, the second sealing surface 112 and the axial end surface of the center longitudinal beam 140 may be welded to achieve a sealed connection to the axial end of the third cavity 141.

[0060] The middle longitudinal beam 140 may also be provided with a fourth cavity 143 extending in the longitudinal direction, and the fourth cavity 143 and the third cavity 141 may be isolated from each other. Figure 6 As shown, the fourth cavity 143 can be located on the upper side of the third cavity 141, and a second rib 144 can be provided between the two. In specific applications, the fourth cavity 143 is also located on the inner side of the power battery box. Therefore, there is no requirement for sealing. At least part of the two axial ports of the fourth cavity 143 and the second sealing surface 112 can be staggered. For details, please refer to Figure 9 , that is, the second sealing surface 112 may not be used to seal the axial port of the fourth cavity 143 , and the second sealing surface 112 may be set relatively small, which can effectively reduce the size of the welding seal.

[0061] A second internal connector can be provided within the fourth cavity 143 for connecting to internal components. Specifically, the second internal connector can be the aforementioned module connector 132b. The internal components may include a battery module, and the module connector 132b can be used to connect to the battery module; the module connector 132b can be, for example, a rivet nut. Alternatively, a second internal connecting hole can be provided in the wall forming the fourth cavity 143. This second internal connecting hole can be isolated from the third cavity 141 and can be a through hole or a blind hole, which can also be used to connect to internal components.

[0062] Furthermore, the power battery box provided by the present invention may also include a front end reinforcement component 150, which is used to connect the front cross beam 110 and the middle longitudinal beam 140, and can improve the connection strength between the front cross beam 110 and the middle longitudinal beam 140, and can improve the anti-collision ability of the front cross beam 110, and can effectively transfer the collision impact force of the front end of the power battery box to the middle longitudinal beam 140.

[0063] The front end reinforcement member 150 can be connected to the front cross member 110 and the middle longitudinal member 140 by welding. Alternatively, the front end reinforcement member 150 can also be connected to the front cross member 110 and the middle longitudinal member 140 by fastening connectors 160 in the form of screws, etc. This implementation method can be seen in Figure 1 、 Figure 2 and Figure 9 , combined with Figure 3 The front cross beam 110 may be integrally formed with a reinforcing fixing column 113 , and the reinforcing fixing column 113 may be used for connection with the screws.

[0064] The present invention further provides a power battery box, comprising a lower box body, which is the lower box body of the power battery box involved in the above-mentioned implementation methods.

[0065] Since the lower case of the power battery mentioned above already has the above technical effects, the power battery having the lower case should also have similar technical effects, so they will not be described in detail here.

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A lower box body of a power battery box, characterized in that: It includes a frame and a bottom plate, wherein the bottom plate and the frame are connected, and the frame includes: A front crossbeam and a rear crossbeam are arranged opposite to each other in the front-to-back direction, and the front crossbeam and the rear crossbeam are formed by a casting process; Two side longitudinal beams are arranged opposite to each other in the left and right directions, both of the side longitudinal beams are located between the front cross beam and the rear cross beam, and both ends of the side longitudinal beams are connected to the front cross beam and the rear cross beam respectively, and both of the side longitudinal beams are extruded profiles; The middle longitudinal beam is located between the two side longitudinal beams and between the front cross beam and the rear cross beam. The two ends of the middle longitudinal beam are respectively connected to the front cross beam and the rear cross beam. The middle longitudinal beam is also an extruded profile.

2. The lower box of the power battery box according to claim 1, characterized in that: The side longitudinal beam comprises a longitudinal beam body, wherein the longitudinal beam body is provided with a first cavity extending in the longitudinal direction, and a first external connecting piece is sealed and assembled in the first cavity.

3. The lower box of the power battery box according to claim 2, characterized in that: The front cross beam and the rear cross beam are both provided with a first blocking surface, and the two first blocking surfaces are respectively sealed and connected to the two axial ends of the first cavity.

4. The lower box of the power battery box according to claim 3, characterized in that: The side longitudinal beam further includes a convex portion, the convex portion being located on the inner side of the longitudinal beam body, the convex portion being provided with a second cavity extending in the longitudinal direction, the second cavity being isolated from the first cavity, and at least portions of two axial ends of the second cavity being offset from the first blocking surface; A first internal connecting piece is provided in the second cavity; or a cavity wall used to form the second cavity is provided with a first internal connecting hole, and the first internal connecting hole is isolated from the first cavity.

5. The lower box of the power battery box according to claim 1, characterized in that: The middle longitudinal beam is provided with a third cavity extending in the longitudinal direction, and a second external connecting piece is sealed and assembled in the third cavity.

6. The lower box of the power battery box according to claim 5, characterized in that: The front cross beam and the rear cross beam are both provided with a second blocking surface, and the two second blocking surfaces are respectively used for sealing connection with the two axial ends of the third cavity.

7. The lower box of the power battery box according to claim 6, characterized in that: The middle longitudinal beam is further provided with a fourth cavity extending in the longitudinal direction, the fourth cavity is isolated from the third cavity, and at least parts of two axial ends of the fourth cavity are staggered with the second blocking surface; A second internal connecting piece is provided in the fourth cavity; or a cavity wall used to form the fourth cavity is provided with a second internal connecting hole, and the second internal connecting hole is isolated from the fourth cavity.

8. The lower box of the power battery box according to any one of claims 1 to 7, characterized in that: It also includes a front end reinforcement component, which is used to connect the front cross beam and the middle longitudinal beam.

9. The lower box of the power battery box according to any one of claims 1 to 7, characterized in that: There are multiple base plates.

10. A power battery box, characterized in that: It comprises a lower box body, which is the lower box body of the power battery box according to any one of claims 1 to 9.

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