CN219873780U - battery pack - Google Patents

Abstract

The utility model relates to the technical field of batteries, in particular to a battery pack, which comprises a box body, wherein the box body comprises a carrier plate, a longitudinal beam and a cross beam, the longitudinal beam and the cross beam are respectively arranged on the carrier plate, the longitudinal beam extends along a first direction, the cross beam extends along a second direction perpendicular to the first direction, and the end part of the longitudinal beam is connected with the cross beam; the connecting part of the longitudinal beam and the cross beam is provided with a reinforcing piece, the reinforcing piece is provided with a first connecting part and a second connecting part which are bent relatively, the first connecting part is connected to at least one of the top surface and the side surface of the longitudinal beam, the second connecting part is connected to the side surface of the cross beam, which faces the longitudinal beam, the side surface of the cross beam is used as a reference surface, the orthographic projection of the second connecting part surrounds the periphery of the orthographic projection of the longitudinal beam on the reference surface, and the bottom of the reinforcing piece and the carrier plate are arranged at intervals to form a gap.

Description

Battery pack

Technical Field

The utility model relates to the technical field of batteries, in particular to a battery pack.

Background

In the design scheme of the existing battery pack, part of battery packs adopt beams to replace end plates to directly provide pretightening force for batteries, when the batteries expand, stress concentration points of the battery packs adopting the design are located at the connection positions of the cross beams and the longitudinal beams, the connection strength of the cross beams and the longitudinal beams of the existing battery packs cannot meet the requirements, and connection failure is easy to occur.

Disclosure of Invention

It is therefore a primary object of the present utility model to overcome at least one of the above-mentioned drawbacks of the prior art and to provide a battery pack having a high strength of connection between the longitudinal and transverse beams of the case.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

according to one aspect of the present utility model, there is provided a battery pack, wherein the battery pack comprises a case including a carrier plate, a side member and a cross member, the side member and the cross member being respectively provided on the carrier plate, the side member extending in a first direction, the cross member extending in a second direction perpendicular to the first direction, an end of the side member being connected to the cross member; the connecting part of the longitudinal beam and the transverse beam is provided with a reinforcing piece, the reinforcing piece is provided with a first connecting part and a second connecting part which are bent relatively, the first connecting part is connected to at least one of the top surface and the side surface of the longitudinal beam, the second connecting part is connected to the side surface of the transverse beam, which faces the longitudinal beam, the side surface of the transverse beam is used as a reference surface, on the reference surface, the orthographic projection of the second connecting part is enclosed on the periphery of the orthographic projection part of the longitudinal beam, and the bottom of the reinforcing piece and the carrier plate are arranged at intervals to form a gap.

According to the technical scheme, the battery pack provided by the utility model has the advantages and positive effects that:

the battery pack is characterized in that a reinforcing piece is arranged at the joint of a longitudinal beam and a cross beam, the reinforcing piece is provided with a first connecting part and a second connecting part which are bent relatively, the first connecting part is connected to at least one of the top surface and the side surface of the longitudinal beam, the second connecting part is connected to the side surface of the cross beam, which faces the longitudinal beam, the side surface of the cross beam is taken as a reference surface, the orthographic projection of the second connecting part is arranged around the periphery of the orthographic projection part of the longitudinal beam on the reference surface, and the bottom of the reinforcing piece and a carrier plate of a box body are arranged at intervals to form a gap. Through the structural design, the connecting strength between the longitudinal beam and the cross beam can be enhanced by utilizing the reinforcing piece, and particularly, the special requirement on the connecting strength of the longitudinal beam and the cross beam when the battery pack directly provides pretightening force for the battery through the cross beam can be met. Because the area of the beam, which is affected by the expansion of the battery and is stressed heavily, is the upper area of the beam, the special stress condition of the beam can be met by utilizing the spacing arrangement of the reinforcing piece and the carrier plate, and meanwhile, the weight of the reinforcing piece can be reduced, so that the beam is beneficial to the lightweight design. In addition, the utility model can also form a glue overflow space by utilizing the gap between the bottom of the reinforcing piece and the carrier plate, thereby facilitating the glue overflow of the glue material between the battery and the carrier plate.

Drawings

Various objects, features and advantages of the present utility model will become more apparent from the following detailed description of the preferred embodiments of the utility model, when taken in conjunction with the accompanying drawings. The drawings are merely exemplary illustrations of the utility model and are not necessarily drawn to scale. In the drawings, like reference numerals refer to the same or similar parts throughout. Wherein:

fig. 1 is a schematic perspective view illustrating a case of a battery pack according to an exemplary embodiment;

FIG. 2 is an enlarged schematic view of portion A of FIG. 1;

FIG. 3 is a cross-sectional view of FIG. 2;

FIG. 4 is an exploded perspective view of FIG. 2;

FIG. 5 is a schematic perspective view of the reinforcement shown in FIG. 2;

fig. 6 is a partially enlarged schematic view of a case of a battery pack according to another exemplary embodiment;

FIG. 7 is a schematic perspective view of the reinforcement shown in FIG. 6;

fig. 8 is a schematic perspective view of a case of a battery pack according to still another exemplary embodiment;

FIG. 9 is an enlarged schematic view of portion B of FIG. 8;

fig. 10 is a schematic perspective view of the support shown in fig. 9.

The reference numerals are explained as follows:

100. a carrier plate;

200. a longitudinal beam;

300. a cross beam;

400. a reinforcing member;

410. a first connection portion;

411. a top surface portion;

412. a side surface portion;

420. a second connecting portion;

430. welding holes;

500. a support beam;

600. a support;

610. a third connecting portion;

620. a fourth connecting portion;

630. a support rib;

C1. a first solder printing;

C2. a second solder printing;

G. a gap;

H1. height of the steel plate;

H2. height of the steel plate;

x, a first direction;

y. second direction.

Detailed Description

Exemplary embodiments that embody features and advantages of the present utility model are described in detail in the following description. It will be understood that the utility model is capable of various modifications in various embodiments, all without departing from the scope of the utility model, and that the description and drawings are intended to be illustrative in nature and not to be limiting.

In the following description of various exemplary embodiments of the utility model, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various exemplary structures, systems, and steps in which aspects of the utility model may be practiced. It is to be understood that other specific arrangements of parts, structures, example devices, systems, and steps may be utilized and structural and functional modifications may be made without departing from the scope of the present utility model. Moreover, although the terms "over," "between," "within," and the like may be used in this description to describe various exemplary features and elements of the utility model, these terms are used herein for convenience only, e.g., in terms of the orientation of the examples depicted in the drawings. Nothing in this specification should be construed as requiring a particular three-dimensional orientation of the structure in order to fall within the scope of the utility model.

Referring to fig. 1, a schematic perspective view of a case of a battery pack according to the present utility model is representatively illustrated. In this exemplary embodiment, the battery pack according to the present utility model is described by taking an in-vehicle battery as an example. Those skilled in the art will readily appreciate that many modifications, additions, substitutions, deletions, or other changes may be made to the specific embodiments described below in order to adapt the relevant designs of the present utility model to other types of battery devices, and such changes remain within the principles of the battery packs presented herein.

As shown in fig. 1, in an embodiment of the present utility model, a battery pack according to the present utility model includes a case and a battery (not shown in the drawings). Referring to fig. 2-5 in conjunction, an enlarged schematic view of portion a of fig. 1 is representatively illustrated in fig. 2; FIG. 3 representatively illustrates a cross-sectional view of FIG. 2;

representatively illustrated in fig. 4 is an exploded perspective view of fig. 2, in particular, with the reinforcement 400 separated from the stringers 200 and cross-beams 300; a schematic perspective view of the stiffener 400 shown in fig. 2 is representatively illustrated in fig. 5. The structure, connection manner and functional relationship of the main components of the battery pack according to the present utility model will be described in detail with reference to the above drawings.

As shown in fig. 1 to 5, the box body includes a carrier plate 100, a longitudinal beam 200 and a cross beam 300, wherein the longitudinal beam 200 and the cross beam 300 are respectively disposed on the carrier plate 100, and the carrier plate 100 may be, for example, a bottom plate, a heat exchange plate, etc. The longitudinal beam 200 extends in a first direction X and the transverse beam 300 extends in a second direction Y, the first direction X being perpendicular to the second direction Y, the end of the longitudinal beam 200 being connected to the transverse beam 300. On this basis, a reinforcing member 400 is provided at the connection between the longitudinal beam 200 and the transverse beam 300, the reinforcing member 400 has a first connecting portion 410 and a second connecting portion 420 which are bent relatively, the first connecting portion 410 is connected to the top surface and the side surface of the longitudinal beam 200, and the second connecting portion 420 is connected to the side surface of the transverse beam 300 facing the longitudinal beam 200. The side surface of the cross member 300 is taken as a reference surface, and on the reference surface, the orthographic projection of the second connection portion 420 of the reinforcement member 400 is surrounded on the outer periphery of the orthographic projection portion of the longitudinal member 200. And, the bottom of the reinforcement 400 is spaced apart from the carrier 100 with a gap G. Through the structural design, the utility model can utilize the reinforcing piece 400 to strengthen the connection strength between the longitudinal beam 200 and the cross beam 300, and particularly can meet the special requirement on the connection strength between the longitudinal beam 200 and the cross beam 300 when the battery pack directly provides pretightening force to the battery through the cross beam 300. Because the area of the beam 300, which is heavily stressed due to the expansion of the battery, is the upper area of the beam, the special stress condition of the beam 300 can be met by arranging the reinforcing member 400 and the carrier plate 100 at intervals, and meanwhile, the weight of the reinforcing member 400 can be reduced, so that the light weight design is facilitated. In addition, the utility model can also form a glue overflow space by utilizing the gap G between the bottom of the reinforcing piece 400 and the carrier plate 100, thereby facilitating glue overflow of the glue material between the battery and the carrier plate 100.

As shown in fig. 3, in an embodiment of the present utility model, a third direction is defined, which is perpendicular to a plane defined by the first direction X and the second direction Y, and a ratio of a height H1 of the orthographic projection of the gap G between the bottom of the reinforcement member 400 and the carrier plate 100 to a height H2 of the orthographic projection of the reinforcement member 400 along the third direction on the above-mentioned reference plane may be 0.1 to 0.6, for example, 0.1, 0.2, 0.3, 0.5, 0.6, etc. Through the structural design, the utility model can avoid the influence of too small gap G on the glue overflow function, and can avoid the defect of insufficient connection reinforcing effect on the longitudinal beam 200 and the transverse beam 300 caused by too large gap G. In some embodiments, the ratio of the height H1 of the front projection of the gap G between the bottom of the stiffener 400 and the carrier 100 to the height H2 of the front projection of the stiffener 400 may be less than 0.1, or may be greater than 0.6, such as 0.095, 0.61, etc., but is not limited to this embodiment.

As shown in fig. 5, in an embodiment of the utility model, the bending portion of the first connecting portion 410 and the second connecting portion 420 of the reinforcement member 400 may have an arc-shaped structure. Through the above structural design, the present utility model can further alleviate the problem of stress concentration at the bending position of the first connecting portion 410 and the second connecting portion 420 by utilizing the structural design of the arc structure, further improve the structural stability of the reinforcement 400, and further enhance the connection strength of the longitudinal beam 200 and the cross beam 300. In some embodiments, the bending portion of the first connecting portion 410 and the second connecting portion 420 of the reinforcement member 400 may have other shapes, such as, but not limited to, a slope-like structure, and the like.

As shown in fig. 4, in an embodiment of the present utility model, the end of the side member 200 is welded to the cross member 300 to form a first weld C1, and the first weld C1 may be schematically seen in the drawings, and in particular, may be understood by the structure of the seam between the edge of the end of the side member 200 and the side surface of the cross member 300. On this basis, the stiffener 400 may cover at least part of the first weld C1. In other words, during the manufacturing process of the box body, the side member 200 and the cross member 300 are welded first, and the first weld mark C1 is formed during the welding process, and then the connection of the reinforcement 400 to the side member 200 and the cross member 300 is performed. Through the above structural design, the present utility model can facilitate the installation of the reinforcement 400 without affecting the assembly of the side member 200 and the cross member 300.

Referring to fig. 6 and 7, a partially enlarged schematic illustration of a case of a battery pack in another exemplary embodiment capable of embodying principles of the present utility model is representatively illustrated in fig. 6; a schematic perspective view of the stiffener 400 shown in fig. 6 is representatively illustrated in fig. 7.

As shown in fig. 6 and 7, in an embodiment of the present utility model, the first connection part 410 and the second connection part 420 of the reinforcement member 400 may be respectively provided with welding holes 430, and the welding holes 430 penetrate the reinforcement member 400 in the thickness direction. On this basis, the first and second connection parts 410 and 420 may be connected to the side members 200 and the cross members 300, respectively, via a filler metal process, whereby the second welding marks C2 are formed in the welding holes 430. Through the above structural design, the present utility model can reduce the number of connection parts required for connecting the reinforcement member 400 with the longitudinal beam 200 and the transverse beam 300 by using a welding process of filling welding, which is beneficial to improving the assembly efficiency.

As shown in fig. 2 to 5, in an embodiment of the present utility model, the first connection portion 410 of the reinforcement member 400 may have an integral top portion 411 and two side portions 412, the top portion 411 is connected to the top surface of the side member 200, and the two side portions 412 are connected to two sides of the side member 200 in the second direction Y, respectively. Through the above structural design, the present utility model can strengthen the connection strength and connection stability of the reinforcement 400 to the side member 200 via the first connection portion 410. In some embodiments, the first connecting portion 410 of the reinforcement member 400 may be connected to only the top surface or at least one side surface of the longitudinal beam 200, which is not limited to the present embodiment.

As shown in fig. 4 and 5, based on the structural design that the first connecting portion 410 of the reinforcement member 400 has a top surface portion 411 and two side surface portions 412, in an embodiment of the present utility model, the second connecting portion 420 may have an "n" shape structure, that is, the second connecting portion 420 is connected to the top surface portion 411 and the two side surface portions 412 of the first connecting portion 410 at the same time. Through the above structural design, the present utility model can easily achieve a larger connection area between the second connection portion 420 and the cross beam 300, and further improve the structural strength of the reinforcement 400. In some embodiments, when the first connecting portion 410 has the top surface portion 411 and two side surface portions 412, the second connecting portion 420 may also have only a portion connected to the top surface portion 411 or at least one side surface portion 412, which is not limited to the present embodiment.

Unlike the structural design in which the first connection portion 410 of the reinforcement member 400 is connected to the surface of the side member 200 in several exemplary embodiments shown in fig. 1 to 7, in an embodiment not shown, when the side member 200 has an inner cavity, the first connection portion 410 of the reinforcement member 400 may also be connected to the cavity wall of the inner cavity. Specifically, the stringers 200 may have an interior cavity that opens at the end of the stringers 200 that are connected to the cross-beams 300. On this basis, the first connecting portion 410 of the reinforcement 400 extends into the inner cavity of the side member 200 and is connected to the wall of the inner cavity, and on the above-mentioned reference plane, the first connecting portion 410 overlaps with the upper portion of the opening of the inner cavity, and the side member 200 is welded to the cross member 300 via the lower portion of the opening of the inner cavity. Through the above structural design, the first connecting portion 410 of the reinforcement member 400 can be accommodated in the inner cavity of the longitudinal beam 200, so that the occupied space of the reinforcement member 400 in the battery pack can be reduced, and the energy density of the battery pack can be improved.

Based on the structural design that the first connecting portion 410 of the reinforcement member 400 is connected to the wall of the inner cavity, in an embodiment not shown, the longitudinal beam 200 and the second connecting portion 420 may be respectively provided with welding holes, and the welding holes penetrate through the longitudinal beam 200 and the reinforcement member 400 along the thickness direction. On this basis, the first connection portion 410 and the second connection portion 420 of the reinforcement 400 may be connected to the side member 200 and the cross member 300, respectively, via a filler metal process, and the second welding marks are formed in the welding holes, respectively.

Referring to fig. 8 to 10, a schematic perspective view of a case of a battery pack in another exemplary embodiment capable of embodying the principles of the present utility model is representatively illustrated in fig. 8; an enlarged schematic view of portion B of fig. 8 is representatively illustrated in fig. 9; a schematic perspective view of the support 600 shown in fig. 9 is representatively illustrated in fig. 10.

As shown in fig. 8 to 10, in an embodiment of the present utility model, the case may further include a support beam 500, the support beam 500 is disposed on the carrier 100, and the support beam 500 is connected to the other side of the cross beam 300 facing away from the longitudinal beam 200. Wherein the height of the support beam 500 may be less than 0.5 times the height of the cross beam 300. On this basis, a support 600 may be connected between the top surface of the support beam 500 and the other side surface of the cross beam 300, and the height of the support 600 may be greater than 0.5 times the height of the cross beam 300, and the top of the support 500 does not exceed the top of the cross beam 300. Through the above structural design, the structural strength of the box body on the side of the beam 300, which is opposite to the longitudinal beam 200, can be enhanced by the support beam 500, and the utility model can prevent the support beam 500 from occupying too much space in the height direction due to the small height of the support beam 500, and can enhance the connection strength between the support beam 500 and the beam 300 by the support member 600.

As shown in fig. 10, based on the structural design that the box further includes the supporting beam 500 and the supporting member 600 is connected between the supporting beam 500 and the cross beam 300, in an embodiment of the present utility model, the supporting member 600 may have a third connecting portion 610 and a fourth connecting portion 620 that are bent relatively, the third connecting portion 610 is connected to the top surface of the supporting beam 500, the third connecting portion 610 is connected to the other side surface of the cross beam 300 (i.e., the side surface of the cross beam 300 facing away from the longitudinal beam 200), and the bending portion of the third connecting portion 610 and the fourth connecting portion 620 may be provided with a supporting rib 630. Through the above structural design, the present utility model can further enhance the supporting effect and the connection strength of the supporting member 600.

As shown in fig. 10, based on the structural design that the support member 600 is connected between the support beam 500 and the cross beam 300 and the support member 600 has the third connection portion 610 and the fourth connection portion 620, in an embodiment of the present utility model, the bent portions of the third connection portion 610 and the fourth connection portion 620 of the support member 600 may have a slant structure. Through the above structural design, the present utility model can further alleviate the problem of stress concentration at the bending position of the third connecting portion 610 and the fourth connecting portion 620 by utilizing the structural design of the inclined plane-like structure, further improve the structural stability of the support 600, and further enhance the connection strength of the support beam 500 and the cross beam 300. In some embodiments, the bent portions of the third connecting portion 610 and the fourth connecting portion 620 of the support 600 may have other shapes, such as, but not limited to, an arc-shaped structure, etc., but not limited to this embodiment.

As shown in fig. 8, based on the structural design that the case further includes the supporting beam 500 and the height of the supporting beam 500 is less than 0.5 times the height of the cross beam 300, in an embodiment of the present utility model, the case has a cavity in which the cross beam 300 is disposed and divides the cavity into a battery compartment accommodating a battery and an electrical compartment accommodating electrical components, in which the longitudinal beam 200 is disposed, and the supporting beam 500 is disposed. On this basis, the supporting beam 500 may be provided with an electric part, which may be a BMS or a BDU, etc. Through the structural design, the space utilization rate of the battery pack can be further improved.

Unlike the exemplary embodiment shown in fig. 8 to 10, which employs a structural design in which the height of the support beam 500 is less than 0.5 times the height of the cross beam 300, in an embodiment, which is not shown, when the case further includes the support beam 500, the height of the support beam 500 may be greater than 1.5 times the height of the cross beam 300. Through the structural design, the high-strength battery pack can provide better supporting force on one side of the cross beam 300, which is opposite to the longitudinal beam 200, by utilizing the supporting beam 500 with higher height, so that the structural strength of the battery pack is further improved.

It should be noted herein that the battery packs shown in the drawings and described in this specification are only a few examples of the wide variety of battery packs that can employ the principles of the present utility model. It should be clearly understood that the principles of the present utility model are in no way limited to any of the details of the battery pack or any of the components of the battery pack shown in the drawings or described in the present specification.

In summary, the battery pack according to the present utility model is provided with the reinforcement member 400 at the connection between the longitudinal beam 200 and the cross beam 300, the reinforcement member 400 has the first connection portion 410 and the second connection portion 420 that are bent relatively, the first connection portion 410 is connected to at least one of the top surface and the side surface of the longitudinal beam 200, the second connection portion 420 is connected to the side surface of the cross beam 300 facing the longitudinal beam 200, the side surface of the cross beam 300 is taken as the reference surface, on the reference surface, the orthographic projection of the second connection portion 420 is surrounded on the outer periphery of the orthographic projection portion of the longitudinal beam 200, and the bottom of the reinforcement member 400 is spaced from the carrier 100 of the box body to have the gap G. Through the structural design, the utility model can utilize the reinforcing piece 400 to strengthen the connection strength between the longitudinal beam 200 and the cross beam 300, and particularly can meet the special requirement on the connection strength between the longitudinal beam 200 and the cross beam 300 when the battery pack directly provides pretightening force to the battery through the cross beam 300. Because the area of the beam 300, which is heavily stressed due to the expansion of the battery, is the upper area of the beam, the special stress condition of the beam 300 can be met by arranging the reinforcing member 400 and the carrier plate 100 at intervals, and meanwhile, the weight of the reinforcing member 400 can be reduced, so that the light weight design is facilitated. In addition, the utility model can also form a glue overflow space by utilizing the gap G between the bottom of the reinforcing piece 400 and the carrier plate 100, thereby facilitating glue overflow of the glue material between the battery and the carrier plate 100.

Exemplary embodiments of the battery pack according to the present utility model are described and/or illustrated in detail above. Embodiments of the utility model are not limited to the specific embodiments described herein, but rather, components and/or steps of each embodiment may be utilized independently and separately from other components and/or steps described herein. Each component and/or each step of one embodiment may also be used in combination with other components and/or steps of other embodiments. When introducing elements/components/etc. that are described and/or illustrated herein, the terms "a," "an," and "the" are intended to mean that there are one or more of the elements/components/etc. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements/components/etc., in addition to the listed elements/components/etc. Furthermore, the terms "first" and "second" and the like in the claims and in the description are used for descriptive purposes only and not for numerical limitation of their subject matter.

While the utility model has been described in terms of various specific embodiments, those skilled in the art will recognize that the utility model can be practiced with modification within the spirit and scope of the claims.

Claims (13)

1. The battery pack is characterized by comprising a box body, wherein the box body comprises a carrier plate, longitudinal beams and cross beams, the longitudinal beams and the cross beams are respectively arranged on the carrier plate, the longitudinal beams extend along a first direction, the cross beams extend along a second direction perpendicular to the first direction, and the end parts of the longitudinal beams are connected with the cross beams; the connecting part of the longitudinal beam and the transverse beam is provided with a reinforcing piece, the reinforcing piece is provided with a first connecting part and a second connecting part which are bent relatively, the first connecting part is connected to at least one of the top surface and the side surface of the longitudinal beam, the second connecting part is connected to the side surface of the transverse beam, which faces the longitudinal beam, the side surface of the transverse beam is used as a reference surface, on the reference surface, the orthographic projection of the second connecting part is enclosed on the periphery of the orthographic projection part of the longitudinal beam, and the bottom of the reinforcing piece and the carrier plate are arranged at intervals to form a gap.

2. The battery pack according to claim 1, wherein a third direction is defined, the third direction being perpendicular to a plane defined by the first direction and the second direction together, and a ratio of a height of orthographic projection of the gap to a height of orthographic projection of the reinforcing member on the reference plane along the third direction is 0.1 to 0.6.

3. The battery pack according to claim 1 or 2, wherein the bent portions of the first connection portion and the second connection portion are in an arc-shaped structure.

4. The battery pack of claim 1, wherein the ends of the longitudinal beams are welded to the transverse beams to form a first weld, and wherein the reinforcement covers at least a portion of the first weld.

5. The battery pack according to claim 4, wherein the first and second connection portions are respectively provided with a welding hole penetrating the reinforcing member in a thickness direction, the first and second connection portions are respectively connected to the side member and the cross member via a filler welding process, and a second welding mark is formed in the welding hole.

6. The battery pack of claim 1, wherein the stringers have an interior cavity open to an end of the stringers to which the cross-beams are connected; the first connecting part stretches into the inner cavity and is connected to the cavity wall of the inner cavity, the first connecting part is overlapped with the upper part of the opening of the inner cavity on the datum plane, and the longitudinal beam is welded and connected with the cross beam through the lower part of the opening of the inner cavity.

7. The battery pack according to claim 6, wherein the side member and the second connecting portion are respectively provided with a welding hole penetrating the side member and the reinforcing member in the thickness direction, the first connecting portion and the second connecting portion are respectively connected to the side member and the cross member via a filler welding process, and a second welding mark is formed in the welding hole.

8. The battery pack according to claim 1, wherein the first connecting portion has an integral top surface portion connected to the top surface of the side member and two side surface portions connected to the two side surfaces of the side member in the second direction, respectively.

9. The battery pack according to claim 8, wherein the second connection part has an "n" -shaped structure, and the second connection part is connected to the top surface part and the two side surface parts of the first connection part at the same time.

10. The battery pack of claim 1, wherein the case further comprises a support beam disposed on the carrier plate, the support beam being connected to the other side of the cross beam facing away from the stringers; wherein the height of the support beam is greater than 1.5 times the height of the cross beam.

11. The battery pack of claim 1, wherein the case further comprises a support beam disposed on the carrier plate, the support beam being connected to the other side of the cross beam facing away from the stringers; wherein the height of the support beam is less than 0.5 times the height of the cross beam; the top surface of the supporting beam and the other side surface of the cross beam are connected with supporting pieces, the height of each supporting piece is 0.5 times that of the cross beam, and the top of each supporting piece does not exceed the top of the cross beam.

12. The battery pack according to claim 11, wherein the support member has a third connecting portion and a fourth connecting portion which are bent relatively, the third connecting portion is connected to the top surface of the support beam, the third connecting portion is connected to the other side surface of the cross beam, and a support rib is provided at a bent portion of the third connecting portion and the fourth connecting portion.

13. The battery pack of claim 11, wherein the housing has a cavity, the cross beam is disposed in the cavity and separates the cavity into a battery compartment and an electrical compartment, the battery compartment houses a battery, the stringers are disposed in the battery compartment, the electrical compartment houses an electrical component, the support beam is disposed in the electrical compartment, and the support beam is provided with the electrical component.