Lower shell structure and battery pack

Abstract

The utility model relates to the technical field of batteries, in particular to a lower shell structure and a battery pack, and provides the lower shell structure which comprises a water-cooling flat plate, a lower shell body and a lower shell body, the water-cooling runner plate is fixed on the bottom surface of the water-cooling flat plate; wherein secondary boundary beams are brazed on the two side edges of the lower surface of the water-cooling runner plate; a main edge beam is welded on one side surface of the secondary edge beam through stirring friction; wherein the part of the upper horizontal plane of the secondary boundary beam is fixed with the lower surface of the water-cooling runner plate by brazing; according to the utility model, the secondary side beam and the water-cooling runner plate are connected through brazing, and the main side beam and the secondary side beam are fused into a whole through friction stir welding, so that the connection strength of the secondary side beam and the water-cooling runner plate is improved, the stress concentration of a riveting connection area is avoided, and meanwhile, the rigidity of the lower shell is improved to a certain extent.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a lower shell structure and a battery pack. Background Art

[0002] Currently, energy storage containers tend to adopt standard container sizes. In order to match standard containers and maximize the overall energy density, energy storage battery packs tend to adopt large-size structural designs, with the length of the energy storage battery pack exceeding 2 meters.

[0003] In some related technologies, the water-cooling plate of the energy storage battery pack is made of 3 series aluminum alloy and is manufactured through a brazing process, and the side beam is made of 6 series aluminum through an integrated extrusion molding process. The 3 series aluminum water-cooling plate and the 6 series aluminum side beam are connected by rivet nuts. Due to the increase in the length of the energy storage battery pack, the stiffness of the entire pack is relatively low. During the vibration process, the connection area between the water-cooling plate and the side beam is severely pulled, and the connection strength does not meet the requirements.

[0004] Therefore, how to solve the problem of insufficient connection strength between the water cooling plate and the side beam connection area is a technical problem that needs to be solved urgently in this field. Utility Model Content

[0005] The utility model provides a lower shell structure and a battery pack to solve the above technical problems.

[0006] In order to achieve the above-mentioned purpose, an embodiment of the utility model provides a lower shell structure, including: a water-cooled flat plate; and a water-cooled runner plate fixed on the bottom surface of the water-cooled flat plate; wherein secondary side beams are brazed on both side edges of the lower surface of the water-cooled runner plate; and a main side beam is stir-friction welded on one side of the secondary side beam; wherein the horizontal surface portion of the secondary side beam is brazed and fixed to the lower surface of the water-cooled runner plate.

[0007] Furthermore, the secondary side beam has a welding surface, a free-standing surface and an inner folding surface; wherein the welding surface and the main side beam are against each other; and the free-standing surface is arranged on the opposite side of the welding surface; and the inner folding surface is arranged on the opposite side of the horizontal plane; wherein the concave direction of the inner folding surface is toward the side away from the water-cooling runner plate.

[0008] Furthermore, the welding surface is fixedly connected to a side surface of the main side beam by stir friction welding; wherein the height between the welding surface and the main side beam is H1; and the thickness of the free surface is H2; wherein 10mm≤H1≤40mm, H2≤H1.

[0009] Furthermore, the main side beam and the secondary side beam are both hollow structures.

[0010] Furthermore, the width of the main side beam is L1, wherein 15mm≤L1≤75mm.

[0011] Furthermore, the secondary side beam is provided with reinforcing ribs inside;

[0012] The thickness of the reinforcement rib is T1; 3mm≤T1≤7mm.

[0013] Furthermore, the distance between the edge of the water-cooling plate and the reinforcing rib is L3.

[0014] Furthermore, the distance between the edge of the water-cooling plate and the welding surface is L2; ​​and the width of the secondary side beam is L4; wherein 5mm≤L2≤L4 / 2; and 0mm≤L3≤L4 / 2.

[0015] Furthermore, the length of the lower shell structure is PL, and the width is PW; wherein 2000mm≤PL≤2300mm, 700mm≤PW≤1200mm.

[0016] The utility model also provides a battery pack, comprising a battery and the lower shell structure as described above; wherein the battery is arranged on the water-cooling plate.

[0017] Compared with the prior art, the utility model connects the secondary side beam and the water-cooling runner plate by brazing, and integrates the main side beam and the secondary side beam by stir friction welding, thereby improving the connection strength between the secondary side beam and the water-cooling plate, avoiding stress concentration in the riveted connection area, and at the same time, improving the rigidity of the lower shell to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0019] Figure 1 A three-dimensional diagram of the optimal embodiment of the lower shell structure of the utility model;

[0020] Figure 2 For this utility model Figure 1 The enlarged structural diagram at A in the middle;

[0021] Figure 3 It is a front view structural schematic diagram of the lower shell structure of the utility model;

[0022] Figure 4 For this utility model Figure 3 Enlarged structural diagram at B in the middle.

[0023] Among them, 1. water-cooled flat plate; 2. water-cooled runner plate; 3. secondary side beam; 31. horizontal plane; 32. welding surface; 33. free surface; 34. inner folding surface; 35. reinforcing rib; 4. main side beam. DETAILED DESCRIPTION

[0024] Now the utility model is further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.

[0025] See also Figure 1 .like Figure 1 As shown, at least one embodiment provides a lower shell structure, including: a water-cooled plate 1; and a water-cooled runner plate 2 fixed on the bottom surface of the water-cooled plate 1; wherein secondary side beams 3 are brazed on both side edges of the lower surface of the water-cooled runner plate 2; the inner contour of the cross section of the secondary side beam 3 is a combination of a rectangular shape and a right-angled trapezoid, and a main side beam 4 is stir-friction welded on one side of the secondary side beam 3, the cross section of the main side beam 4 is rectangular, and the main side beam 4 is extruded from 6 series aluminum. The secondary side beam 3 is extruded from 3 series aluminum, and the water-cooled plate 1 is also extruded from 3 series aluminum. The secondary side beam 3 is connected to the water-cooled plate 1 by brazing, so as to achieve a strong connection in the entire overlapping area of ​​the secondary side beam 3 and the water-cooled plate 1, and the width of the lower shell structure is PW and the length is PL; wherein 2000mm≤PL≤2300mm, 700mm≤PW≤1200mm.

[0026] Please continue reading Figure 1 Combined with Figures 2 to 4 , Figure 2 For this utility model Figure 1 The enlarged structural diagram at A in the middle; Figure 3 It is a front view structural schematic diagram of the lower shell structure of the utility model; Figure 4 For this utility model Figure 3 The enlarged structural diagram at B in the figure. Figures 1 to 4 As shown, the secondary side beam 3 has a horizontal surface 31, a welding surface 32, a free surface 33 and an inner folding surface 34. The welding surface 32 and the main side beam 4 are against each other; the free surface 33 is arranged on the opposite side of the welding surface 32; and the inner folding surface 34 is arranged on the opposite side of the horizontal surface 31, wherein the inner folding surface 34 is concave toward a side away from the water-cooling runner plate 2, and a part of the horizontal surface 31 is brazed and fixedly connected to the water-cooling runner plate 2. The welding surface 32 is fixedly connected to one side of the main side beam 4 by stir friction welding. Both the main side beam 4 and the secondary side beam 3 are hollow structures. The height between the welding surface 32 and the main side beam 4 is H1; and the thickness of the free surface 33 is H2; H1 is the height value of the main side beam 4, and also the height value of the outer side of the secondary side beam 3, that is, the height value of the welding surface 32, which will greatly affect the dimensional design of the height direction of the battery pack; if H1 is too large, the main side beam 4 will occupy too much design space in the height direction of the battery pack, seriously affecting the design space of the battery pack outer shell and the internal battery cells, bars and other key components; if H1 is too small, the main side beam 3 is insufficient in rigidity, seriously affecting the structural safety of the battery pack. Based on design considerations, 10mm≤H1≤40mm, H2≤H1.

[0027] Please continue reading Figure 4 .like Figure 4 As shown, in order to further enhance the supporting strength of the secondary side beam 3, a reinforcing rib 35 is provided inside the secondary side beam 3. The thickness of the reinforcing rib 35 is T1, wherein 3mm≤T1≤7mm.

[0028] Please continue reading Figure 4 .like Figure 4 As shown, the width of the main side beam 4 is L1; and the width of the secondary side beam 3 is L4; and the distance between the edge of the water-cooling plate 1 and the welding surface 32 is L2; ​​and the distance between the edge of the water-cooling plate 1 and the reinforcing rib 35 is L3; and 15mm≤L1≤75mm; In addition, if the overlapping brazing area between the water-cooling plate 1 and the secondary side beam 3 is too small, the connection strength of the water-cooling plate 1 is insufficient, and the water-cooling plate 1 is prone to cracking during vibration. If the overlapping brazing area between the water-cooling plate 1 and the secondary side beam 3 is too large, the risk of brazing defects increases, and the weight of the parts increases unreasonably. The edge of the water-cooling plate 1 should maintain a certain distance from the intersection area of ​​the secondary side beam 3 and the main side beam 4 to avoid stress concentration in the intersection area of ​​the secondary side beam 3 and the main side beam 4, 5mm≤L2≤L4 / 2; and 0mm≤L3≤L4 / 2.

[0029] The utility model further provides a battery pack, comprising a battery and the lower shell structure as described above; wherein the battery is arranged on the water-cooled flat plate 1.

[0030] In summary, the utility model connects the secondary side beam 3 and the water-cooling runner plate 2 by brazing, and integrates the main side beam 4 and the secondary side beam 3 by stir friction welding, thereby improving the connection strength between the secondary side beam 3 and the water-cooling runner plate 2, avoiding stress concentration in the riveted connection area, and at the same time, improving the rigidity of the lower shell to a certain extent.

[0031] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without deviating from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A lower shell structure, characterized in that: include: Water-cooled plate (1); and A water-cooling channel plate (2) fixed to the bottom surface of the water-cooling flat plate (1); in Secondary side beams (3) are brazed on both side edges of the lower surface of the water-cooling channel plate (2); and A main side beam (4) is welded to one side of the secondary side beam (3) by stir friction welding; The portion of the upper horizontal surface (31) of the secondary side beam (3) and the lower surface of the water-cooling channel plate (2) are fixed by brazing.

2. The lower housing structure according to claim 1, characterized in that: The secondary side beam (3) comprises a welding surface (32), a free-standing surface (33) and an inner folding surface (34); wherein The welding surface (32) and the main side beam (4) abut against each other; and The vacant surface (33) is arranged on the opposite side of the welding surface (32); and The inner folding surface (34) is arranged on the opposite side of the horizontal surface (31); wherein The inner folded surface (34) is recessed in a direction facing a side away from the water-cooling channel plate (2).

3. The lower housing structure according to claim 2, characterized in that: The welding surface (32) is fixedly connected to a side surface of the main side beam (4) by means of friction stir welding; wherein The height between the welding surface (32) and the main side beam (4) is H1; and The thickness of the vacated surface (33) is H2; wherein 10mm≤H1≤40mm, H2≤H1.

4. The lower housing structure according to claim 1, characterized in that: The main side beam (4) and the secondary side beam (3) are both hollow structures.

5. The lower housing structure according to claim 1, characterized in that: The width of the main side beam (4) is L1; wherein 15mm≤L1≤75mm.

6. The lower housing structure according to claim 2, characterized in that: A reinforcing rib (35) is provided inside the secondary side beam (3); wherein The thickness of the reinforcing rib (35) is T1; 3mm≤T1≤7mm.

7. The lower housing structure according to claim 6, characterized in that: The distance between the edge of the water-cooling plate (1) and the reinforcing rib (35) is L3.

8. The lower housing structure according to claim 7, characterized in that: The distance between the edge of the water-cooling plate (1) and the welding surface (32) is L2; ​​and The width of the secondary side beam (3) is L4; wherein 5mm≤L2≤L4 / 2; and 0mm≤L3≤L4 / 2.

9. The lower housing structure according to claim 1, characterized in that: The length of the lower shell structure is PL, and the width is PW; 2000mm≤PL≤2300mm, 700mm≤PW≤1200mm.

10. A battery pack, characterized in that: include Batteries; and The lower shell structure according to any one of claims 1 to 9; The battery is arranged on the water-cooling plate (1).

Images