Battery box

Abstract

The embodiment of the utility model provides a battery box. The battery box comprises two longitudinal beams, at least one middle beam and a first welding part, first grooves are formed in the two longitudinal beams, the two ends of the middle beam are arranged in the first grooves of the two longitudinal beams respectively, and the first welding parts are arranged along notches of the first grooves so as to connect the longitudinal beams and the middle beam; the longitudinal beam and the middle beam are connected by arranging the first welding part at the notch of the first groove, so that the connection of the longitudinal beam and the middle beam is reinforced, and the mechanical strength of the longitudinal beam and the middle beam is improved; the longitudinal beam is provided with a first groove, and the end part of the middle beam is inserted into the first groove, so that even if the battery cell expands to generate expansion force on the middle beam to cause connection cracking between the first welding part and the middle beam / longitudinal beam, the groove wall of the first groove can also form abutting force on the middle beam, and a mortise and tenon connection structure is still maintained between the middle beam and the longitudinal beam; and the probability of connection failure of the middle beam and the longitudinal beam is reduced, so that the middle beam can effectively resist the expansive force of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and more specifically, to a battery box. Background Art

[0002] In the related art, inside the battery box, the end face of the crossbeam abuts the surface of the longitudinal beam, and then a weld is formed by welding the end face of the crossbeam and the longitudinal beam at the abutment portion using a welding bar to fix them. The middle beam is also connected to the longitudinal beam in the same way. This connection method between the crossbeam and the longitudinal beam or the middle beam and the longitudinal beam has low mechanical strength, making the crossbeam / middle beam unable to resist the expansion force generated by the battery cell on the crossbeam / middle beam during its cycle life. The expansion force generated by the battery cell during its cycle life will pull on the weld and the crossbeam / middle beam, which will lead to cracking of the weld and failure of the mechanical connection between the crossbeam / middle beam and the longitudinal beam, causing the crossbeam / middle beam to lose its supporting function and ability to resist the expansion force of the battery cell. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a battery box in which the mechanical connection between the middle beam and the longitudinal beam is firm and the mechanical strength is high, and the middle beam has a strong ability to resist the expansion force of the battery cell.

[0004] An embodiment of the present application provides a battery box, comprising:

[0005] longitudinal beams, the longitudinal beams comprising two, both of which extend along a first direction and are arranged in parallel along a second direction, the second direction intersecting the first direction, each of the longitudinal beams having a first groove formed thereon, the first grooves on the two longitudinal beams being arranged correspondingly along the second direction;

[0006] at least one middle beam, with two ends of the middle beam respectively disposed in the two first grooves; and

[0007] The first welding portion is arranged along the notch of the first groove, and the first welding portion is connected to the longitudinal beam and the middle beam.

[0008] In one embodiment, a portion of the first welding portion extends into the first groove.

[0009] In one embodiment, the two first grooves are respectively provided on opposite surfaces of the two longitudinal beams, and the depth of the first groove is smaller than the width of the longitudinal beam along the second direction.

[0010] In one embodiment, as the depth of the first groove increases, the width of the first groove decreases.

[0011] In one embodiment, first accommodating grooves are provided on opposite surfaces of the two longitudinal beams, the first accommodating grooves are connected to or spaced apart from the first grooves, and a portion of the first welding portion is further extended into the first accommodating grooves.

[0012] In one embodiment, the first accommodating groove is a square groove, an arc groove or an oblique groove.

[0013] In one embodiment, a reinforcement groove is further formed at the end of the middle beam, the reinforcement groove corresponds to the notch of the first groove, and a portion of the first welding portion further extends into the reinforcement groove.

[0014] In one embodiment, each longitudinal beam is provided with a second groove, and two second grooves are provided on opposite surfaces of the two longitudinal beams along the second direction.

[0015] The battery box also includes a first cross beam, which includes a main body and a limiting portion. The limiting portion is connected to the main body, and both the main body and the limiting portion extend along the second direction. The first end face of the longitudinal beam along the first direction abuts against the main body, and one end of the limiting portion is arranged in the second groove.

[0016] In one embodiment, second accommodating grooves are further provided on opposite surfaces of the two longitudinal beams, and the second accommodating grooves are connected to or spaced apart from the second grooves;

[0017] The battery box further includes a second welding portion, which is arranged along the notch of the second groove and extends into the second accommodating groove. The second welding portion is connected to the longitudinal beam and the limiting portion.

[0018] In one embodiment, a lap groove is provided on the main body, and the lap groove includes an adjacent first wall and a second wall. The longitudinal beam is lapped on the first wall, and the end face of the longitudinal beam along the first direction abuts against the second wall. The limiting portion protrudes from the first wall along the second direction, and the portion of the limiting portion protruding from the first wall is arranged in the second groove.

[0019] In one embodiment, the battery box further includes a third welding portion, which is provided along a notch of the lap groove, and is connected to the longitudinal beam and the main body.

[0020] In one embodiment, the battery box further includes a second crossbeam, the second crossbeam extending along the second direction, and the second end surface of the longitudinal beam along the first direction abuts against the second crossbeam;

[0021] The second crossbeam and the middle beam adjacent to the second crossbeam are both provided with third grooves. A support structure is provided between the adjacent second crossbeams and the middle beam. Both ends of the support structure are respectively provided in the two third grooves.

[0022] In one embodiment, the two third grooves are respectively provided on the opposite surfaces of the adjacent second cross beam and the middle beam, and the opposite surfaces of the adjacent second cross beam and the middle beam are further provided with a third accommodating groove, and the third accommodating groove is connected to or spaced from the third groove.

[0023] The battery box also includes a fourth welding portion, which is arranged along the notch of the third groove and extends into the third accommodating groove. The fourth welding portion is connected to the second beam and to the middle beam adjacent to the second beam.

[0024] The beneficial effects of the battery box provided by the embodiment of the present application are: the battery box of the present application includes two longitudinal beams, at least one middle beam and a first welding part; compared with the related art, a first groove is provided on the two longitudinal beams of the present application, and the two end portions of the middle beam are respectively arranged in the first grooves of the two longitudinal beams, and the first welding part is arranged along the notch of the first groove to connect the longitudinal beam and the middle beam; on the one hand, the longitudinal beam and the middle beam are connected by the first welding part arranged in the notch of the first groove, so as to reinforce the connection between the longitudinal beam and the middle beam and improve the mechanical strength of the longitudinal beam and the middle beam; on the other hand, since the first groove is provided on the longitudinal beam and the end portion of the middle beam is inserted into the first groove, even if the expansion of the battery cell generates an expansion force on the middle beam and causes the connection between the first welding part and the middle beam / longitudinal beam to crack, the groove wall of the first groove will also form an abutment force on the middle beam, and the mortise and tenon connection structure is still maintained between the middle beam and the longitudinal beam, reducing the probability of failure of the connection between the middle beam and the longitudinal beam, so that the middle beam can effectively resist the expansion force of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0026] Figure 1 A schematic structural diagram of a battery box provided in one embodiment of the present application;

[0027] Figure 2 for Figure 1 Schematic diagram of the enlarged structure of area A in the middle;

[0028] Figure 3 for Figure 1 Schematic diagram of the cross-sectional structure of area A;

[0029] Figure 4 A schematic cross-sectional view of the longitudinal beam, the middle beam, and the first welding portion of a battery box provided in another embodiment of the present application;

[0030] Figure 5 A schematic cross-sectional view of the longitudinal beam, the middle beam, and the first welding portion of a battery box according to another embodiment of the present application;

[0031] Figure 6 for Figure 1 Schematic diagram of the enlarged structure of the middle R region;

[0032] Figure 7 A schematic structural diagram of a first crossbeam in a battery box provided in one embodiment of the present application;

[0033] Figure 8 for Figure 1 Schematic diagram of the enlarged structure of the E region in the middle;

[0034] Among them, the reference numerals in the figures are:

[0035] Battery box 100; longitudinal beam 110; middle beam 120; cross beam 130; first cross beam 131; second cross beam 132; main body 131A; limiting portion 131B; support structure 140;

[0036] First groove U1; second groove U2; first welding portion W1; second welding portion W2; third welding portion W3; fourth welding portion W4; first receiving groove C; reinforcement groove P; overlapping groove T; first wall S1; second wall S2;

[0037] First direction X; second direction Y. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0039] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0040] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0042] Please also refer to Figures 1 to 3 Now, the battery box 100 provided in the embodiment of the present application is described. Figure 1 As shown, the battery box 100 includes two longitudinal beams 110, at least one intermediate beam 120 and a first welding portion W1. Both longitudinal beams 110 extend along a first direction X, and the two longitudinal beams 110 are arranged side by side along a second direction Y, and the second direction Y intersects the first direction X. A first groove U1 is provided on each longitudinal beam 110, and the first grooves U1 on the two longitudinal beams 110 are arranged correspondingly along the second direction Y. The two ends of the intermediate beam 120 are respectively arranged in the first grooves U1 of the two longitudinal beams 110. The first welding portion W1 is arranged along the notch of the first groove U1, and the first welding portion W1 is connected to the longitudinal beams 110 and to the intermediate beam 120.

[0043] Optional, such as Figure 2 As shown, one intermediate beam 120 includes four first welds W1. Two first welds W1 are provided at one end of the intermediate beam 120, and two first welds W1 are provided at the other end. Taking one end of the intermediate beam 120 as an example, one first weld W1 is provided along one side of the notch of the first groove U1, and another first weld W1 is provided along the opposite side of the notch of the first groove U1, thereby welding the intermediate beam 120 to the longitudinal beam 110.

[0044] In addition, the first groove U1 can also be used to position the middle beam 120 during assembly, and the positioning structure can be omitted in the clamping tool, which simplifies the clamping tool and also simplifies the assembly process of the longitudinal beam 110 and the middle beam 120.

[0045] The battery box 100 provided in the embodiment of the present application connects the longitudinal beam 110 and the middle beam 120 through the first welding portion W1 set at the notch of the first groove U1, thereby reinforcing the connection between the longitudinal beam 110 and the middle beam 120 and improving the mechanical strength of the longitudinal beam 110 and the middle beam 120; on the other hand, since the first groove U1 is opened on the longitudinal beam 110 and the end of the middle beam 120 is inserted into the first groove U1, even if the expansion of the battery cell generates an expansion force on the middle beam 120 and causes the connection between the first welding portion W1 and the middle beam 120 / longitudinal beam 110 to crack, the groove wall of the first groove U1 will also form an abutment force on the middle beam 120, and the mortise and tenon connection structure between the middle beam 120 and the longitudinal beam 110 is still maintained, reducing the probability of failure of the connection between the middle beam 120 and the longitudinal beam 110, so that the middle beam 120 can effectively resist the expansion force of the battery cell.

[0046] like Figure 3 As shown, the center beam 120 is inserted into the first groove U1, and the first weld portion W1 extends from the notch of the first groove U1 into the first groove U1, that is, part of the first weld portion W1 extends into the first groove U1. During the welding process, solder is applied at the junction of the center beam 120 and the longitudinal beam 110, that is, at the notch of the first groove U1. In one embodiment, the first groove U1 has redundant space beyond the space for the center beam 120, and solder is also applied to the edge of the first groove U1. After welding the solder, the longitudinal beam 110, and the center beam 120, the first weld portion W1 is formed. The first weld portion W1 is provided at the notch of the first groove U1 and extends into the first groove U1. It is understood that more solder can be applied to the first groove U1, which can provide better weld strength after welding, thereby enhancing the mechanical connection strength between the center beam 120 and the longitudinal beam 110.

[0047] In this embodiment, two first grooves U1 are provided on opposing surfaces of the two longitudinal beams 110. Specifically, the intermediate beam 120 is inserted into opposing surfaces of the two longitudinal beams 110 to form a mortise and tenon structure. Compared to related art, the width of the longitudinal beams 110 in this application is increased along the second direction Y to provide greater support and structural strength for the battery pack. In this embodiment, the width of the longitudinal beams 110 is between 35 millimeters (mm) and 60 mm, for example, 35 mm, 40 mm, 50 mm, 55 mm, or 60 mm. The depth of the first grooves U1 is less than the width of the longitudinal beams 110 along the second direction Y. This ensures that the longitudinal beams 110 have sufficient support and structural strength while retaining the intermediate beams 120 within the first grooves U1. Optionally, the depth of the first grooves U1 is between 20 mm and 40 mm, for example, 20 mm, 25 mm, 30 mm, 35 mm, or 40 mm. Optionally, the ratio of the depth of the first grooves U1 to the width of the longitudinal beams 110 is between 1 / 3 and 2 / 3.

[0048] Optionally, in some embodiments, two first grooves U1 are respectively provided on the top surfaces of the two longitudinal beams 110 , so that the middle beam 120 can be overlapped on the top surfaces of the two longitudinal beams 110 and inserted and fixed in the first grooves U1 .

[0049] like Figure 3 As shown, the ends of the middle beam 120 are further provided with reinforcement grooves P, which correspond to the notches of the first recesses U1. Specifically, the reinforcement grooves P are provided on both sides of the middle beam 120 along the second direction Y. Portions of the first weld portion W1 also extend into the reinforcement grooves P. As will be appreciated, by providing the reinforcement grooves P at the ends of the middle beam 120, more solder can be accommodated within the grooves P. The resulting first weld portion W1 also extends into the grooves P, strengthening the connection between the first weld portion W1 and the middle beam 120 and thereby reinforcing the connection between the middle beam 120 and the longitudinal beam 110. Furthermore, as will be appreciated, the first weld portion W1 is partially embedded within the reinforcement grooves P. When the middle beam 120 is subjected to expansion forces or becomes loose, portions of the first weld portion W1 will resist the groove walls of the reinforcement grooves P in the second direction Y, thereby strengthening the connection between the middle beam 120 and the longitudinal beam 110.

[0050] Optionally, in some other embodiments, as the depth of the first groove U1 increases, the width of the first groove U1 decreases, such as Figure 4 As shown. That is, the cross-section of the first groove U1 is an inverted trapezoid. As can be understood, the deeper the intermediate beam 120 is inserted into the first groove U1, the more interference fit is achieved between the intermediate beam 120 and the longitudinal beam 110, resulting in a more stable connection. Furthermore, the closer the inverted trapezoidal first groove U1 is to the notch, the more redundant space there is for solder. This allows the first weld portion W1 to extend into the first groove U1, strengthening the connection between the intermediate beam 120 and the longitudinal beam 110.

[0051] Please continue reading Figure 4 ,exist Figure 4In the embodiment, first receiving grooves C are provided on opposing surfaces of the two longitudinal beams 110, and the first receiving grooves C are spaced apart from the first grooves U1. Part of the first welding portion W1 also extends into the first receiving grooves C. It is understandable that the first receiving grooves C are further provided to provide more space for accommodating solder, and the solder is continuously filled in the first receiving grooves C, the first grooves U1, and the reinforcement grooves P. After welding, the first welding portion W1 is formed, which further increases the connection strength between the first welding portion W1 and the longitudinal beams 110 and the middle beam 120. In addition, part of the first welding portion W1 is provided in the first receiving grooves C. When the middle beam 120 is pulled by the expansion force of the battery cell and the first welding portion W1 is pulled, the groove wall of the first receiving groove C forms a resistance force in the first direction X against the first welding portion W1, thereby reducing the possibility of cracking between the first welding portion W1 and the longitudinal beam 110 and improving the mechanical connection strength. The first receiving groove C and the first groove U1 are spaced apart, so that the first welding material portion continuously arranged at the notch of the first receiving groove C and the first groove U1 is engaged with the longitudinal beam 110, further improving the fixing strength of the first welding material and the longitudinal beam 110. Figure 4 As shown, the first receiving groove C is an oblique groove, and the possibility of the first welding portion W1 falling off is reduced due to the setting of the oblique groove. Optionally, the first receiving groove C can also be a square groove or an arc groove, as long as it can provide more space for solder accommodating. Figure 5 As shown, the first accommodating groove C is communicated with the first groove U1, and the first accommodating groove C is an arc-shaped groove.

[0052] Please also refer to Figures 6 to 8 , Figures 6 to 8 for Figure 1 The corresponding structural diagram in the embodiment. Figure 1 In the embodiment, the battery box 100 includes two crossbeams 130, and the two crossbeams 130 include a first crossbeam 131 and / or a second crossbeam 132. Optionally, both crossbeams 130 have the structure of the first crossbeam 131, or both crossbeams 130 have the structure of the second crossbeam 132, or one crossbeam 130 has the structure of the first crossbeam 131 and the other crossbeam 130 has the structure of the second crossbeam 132.

[0053] In this embodiment, one crossbeam 130 has the structure of a first crossbeam 131, and the other crossbeam 130 has the structure of a second crossbeam 132. The first crossbeam 131 will be described below.

[0054] Specifically, such as Figure 6As shown, the first crossbeam 131 includes a main body 131A and a stopper 131B. The stopper 131B is connected to the main body 131A and both extend along the second direction Y. A second groove U2 is defined in each longitudinal beam 110. Two second grooves U2 are disposed on opposite sides of the two longitudinal beams 110 along the second direction Y. Each longitudinal beam 110 has a first end face and a second end face. The first end face of one longitudinal beam 110 along the first direction X abuts one end of the main body 131A, while the first end face of the other longitudinal beam 110 along the first direction X abuts the other end of the main body 131A. The ends of the stopper 131B are disposed in the second grooves U2 of the two longitudinal beams 110, respectively. The first crossbeam 131 is in contact with the longitudinal beam 110 through the main body 131A to form an accommodating space for accommodating the battery pack; the first crossbeam 131 is inserted into the second groove U2 through the limiting portion 131B, so that when the first crossbeam 131 is subjected to the expansion force of the battery cell, the groove wall of the second groove U2 forms an abutting force on the first crossbeam 131, reducing the probability of failure of the connection between the first crossbeam 131 and the longitudinal beam 110, so that the first crossbeam 131 can effectively resist the expansion force of the battery cell.

[0055] like Figure 7 As shown, the main body 131A is provided with a lap groove T, which includes adjacent first and second walls S1 and S2. The longitudinal beam 110 is overlapped on the first wall S1, and the end surface of the longitudinal beam 110 along the first direction X abuts the second wall S2. The limiting portion 131B protrudes from the first wall S1 along the second direction Y, and the portion of the limiting portion 131B protruding from the first wall S1 is disposed in the second groove U2. It can be understood that the limiting portion 131B protrudes from the first wall S1, and the protruding portion is disposed in the second groove U2, so that the limiting portion 131B and the longitudinal beam 110 form a mortise and tenon structure to enhance mechanical strength, and the two side walls of the second groove U2 can form a resistance force in the first direction X against the protruding portion of the limiting portion 131B. Furthermore, the first wall S1, the second wall S2 and the portion of the limiting portion 131B protruding from the first wall S1 form an engagement groove, and the main body 131A and the limiting portion 131B cooperate with the longitudinal beam 110 to form an engagement structure, greatly enhancing the stability of the first cross beam 131 and the longitudinal beam 110.

[0056] Please refer again Figure 6The battery box 100 also includes a second welding portion W2 and a third welding portion W3. The second welding portion W2 is arranged along the notch of the second groove U2. The second welding portion W2 is connected to the longitudinal beam 110 and to the limiting portion 131B. It can be understood that the provision of the second welding portion W2 strengthens the connection strength between the limiting portion 131B and the longitudinal beam 110. In this embodiment, the second welding portion W2 includes two, respectively provided at both ends of the limiting portion 131B. Optionally, a second accommodating groove can be provided on the longitudinal beam 110 and a reinforcement groove can be provided on the limiting portion 131B. The second welding portion W2 extends into the second accommodating groove and the reinforcement groove on the limiting portion 131B to strengthen the connection strength between the limiting portion 131B and the longitudinal beam 110. The third welding portion W3 is arranged along the notch of the lap groove T. The third welding portion W3 is connected to the longitudinal beam 110 and to the main body 131A, thereby strengthening the connection strength between the main body 131A and the longitudinal beam 110.

[0057] Next, the second beam 132 will be described.

[0058] Specifically, such as Figure 8 As shown, the second crossbeam 132 extends along the second direction Y, and the second end face of the longitudinal beam 110 along the first direction X abuts the second crossbeam 132. Two intermediate beams 120 are provided in the accommodation space enclosed by the first crossbeam 131, the second crossbeam 132 and the two longitudinal beams 110. An intermediate beam 120 is arranged adjacent to the second crossbeam 132. A third groove (not shown) is provided on the second crossbeam 132 and the intermediate beam 120 adjacent to the second crossbeam 132. A support structure 140 is provided between the adjacent second crossbeams 132 and the intermediate beams 120, and the two ends of the support structure 140 are respectively arranged in the two third grooves. Optionally, the support structure 140 extends along the first direction X, or extends along other directions, as long as the extension direction of the support structure 140 intersects with the second direction Y. The arrangement of the support structure 140 can provide support force for the intermediate beam 120 and the second crossbeam 132 connected thereto to resist the expansion force of the battery cells. The provision of the third groove can strengthen the connection strength between the support structure 140 and the second crossbeam 132 , as well as the connection strength between the intermediate beam 120 connected to the support structure 140 and the support structure 140 .

[0059] Battery case 100 also includes a fourth weld portion W4, which is disposed along the notch of the third groove. This weld portion W4 is connected to second crossbeam 132 and to intermediate beam 120 adjacent to second crossbeam 132, thereby strengthening the connection between support structure 140 and second crossbeam 132 / intermediate beam 120.

[0060] The above is a description of the battery box 100 provided in the embodiment of the present application.

[0061] An embodiment of the present application provides a battery box including two longitudinal beams, at least one middle beam and a first welding portion; a first groove is provided on the two longitudinal beams, and the two end portions of the middle beam are respectively arranged in the first grooves of the two longitudinal beams, and the first welding portion is arranged along the notch of the first groove to connect the longitudinal beams and the middle beams; on the one hand, the longitudinal beams and the middle beams are connected by the first welding portion arranged in the notch of the first groove, so as to reinforce the connection between the longitudinal beams and the middle beams and improve the mechanical strength of the longitudinal beams and the middle beams; on the other hand, since the first groove is provided on the longitudinal beam and the end portion of the middle beam is inserted into the first groove, even if the expansion of the battery cell generates an expansion force on the middle beam and causes the connection between the first welding portion and the middle beam / longitudinal beam to crack, the groove wall of the first groove will also form an abutment force on the middle beam, and the mortise and tenon connection structure between the middle beam and the longitudinal beam is still maintained, thereby reducing the probability of failure of the connection between the middle beam and the longitudinal beam, so that the middle beam can effectively resist the expansion force of the battery cell.

[0062] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A battery box, characterized in that: include: longitudinal beams, the longitudinal beams comprising two, both of which extend along a first direction and are arranged in parallel along a second direction, the second direction intersecting the first direction, each of the longitudinal beams having a first groove formed thereon, the first grooves on the two longitudinal beams being arranged correspondingly along the second direction; at least one middle beam, with two ends of the middle beam respectively disposed in the two first grooves; as well as The first welding portion is arranged along the notch of the first groove, and the first welding portion is connected to the longitudinal beam and the middle beam.

2. The battery box according to claim 1, wherein: A portion of the first welding portion extends into the first groove.

3. The battery box according to claim 1, wherein: The two first grooves are respectively arranged on opposite surfaces of the two longitudinal beams, and the depth of the first grooves is smaller than the width of the longitudinal beams along the second direction.

4. The battery box according to claim 3, wherein: As the depth of the first groove increases, the width of the first groove decreases.

5. The battery box according to claim 3, wherein: First accommodating grooves are provided on opposite surfaces of the two longitudinal beams. The first accommodating grooves are communicated with or spaced apart from the first grooves, and a portion of the first welding portion is further extended into the first accommodating grooves.

6. The battery box according to claim 5, characterized in that: The first receiving groove is a square groove, an arc groove or an oblique groove.

7. The battery box according to claim 1, wherein: A reinforcement groove is further provided at the end of the middle beam, the reinforcement groove corresponds to the notch of the first groove, and a portion of the first welding portion further extends into the reinforcement groove.

8. The battery box according to claim 1, wherein: A second groove is formed on each longitudinal beam, and two second grooves are respectively provided on opposite surfaces of the two longitudinal beams along the second direction; The battery box also includes a first cross beam, which includes a main body and a limiting portion. The limiting portion is connected to the main body, and both the main body and the limiting portion extend along the second direction. The first end face of the longitudinal beam along the first direction abuts against the main body, and one end of the limiting portion is arranged in the second groove.

9. The battery box according to claim 8, wherein: The battery box further includes a second welding portion, which is arranged along the notch of the second groove, and the second welding portion is connected to the longitudinal beam and the limiting portion.

10. The battery box according to claim 8, wherein: A lap groove is provided on the main body, and the lap groove includes an adjacent first wall and a second wall. The longitudinal beam is lapped on the first wall, and the end face of the longitudinal beam along the first direction abuts against the second wall. The limiting portion protrudes from the first wall along the second direction, and the portion of the limiting portion protruding from the first wall is arranged in the second groove.

11. The battery box according to claim 10, wherein: The battery box further includes a third welding portion, which is arranged along the notch of the lap groove and is connected to the longitudinal beam and the main body.

12. The battery box according to claim 1, wherein: The battery box further includes a second crossbeam, the second crossbeam extending along the second direction, and the second end surface of the longitudinal beam along the first direction abuts against the second crossbeam; The second crossbeam and the middle beam adjacent to the second crossbeam are both provided with third grooves. A support structure is provided between the adjacent second crossbeams and the middle beam. Both ends of the support structure are respectively provided in the two third grooves.

13. The battery box according to claim 12, wherein: The battery box further includes a fourth welding portion, which is arranged along the notch of the third groove. The fourth welding portion is connected to the second crossbeam and to the middle beam adjacent to the second crossbeam.

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