Lower shell assembly and battery pack

Abstract

The utility model relates to the technical field of batteries, in particular to a lower shell assembly and a battery pack, and provides the lower shell assembly which comprises a water-cooling flat plate, an upper 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 friction stir; wherein the part of the inner folding surface on the secondary boundary beam is connected with the water-cooling runner plate through brazing; according to the utility model, the auxiliary boundary beam is connected with the water-cooling flat plate through brazing, the main boundary beam and the auxiliary boundary beam are fused into a whole through friction stir welding, and meanwhile, the auxiliary boundary beam is in a vertically downward concave section type by designing the inner folding surface, so that the connection strength of the auxiliary boundary beam and the water-cooling runner plate is improved, the stress concentration of a riveting connection area is avoided, and the service life of the water-cooling runner plate is prolonged. 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 component 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 component 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 assembly, 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 to one side of the secondary side beam; wherein a portion of the inner folded surface on the secondary side beam is connected to the water-cooled runner plate by brazing.

[0007] Furthermore, the secondary side beam also has a horizontal plane, a welding plane and a free-standing plane; wherein the welding plane and the main side beam are against each other; and the free-standing plane is arranged on the opposite side of the welding plane; and the inner folding plane is arranged on the opposite side of the horizontal plane.

[0008] Furthermore, the welding surface is fixedly connected to one side surface of the main side beam by stir friction welding; wherein the height between the welding surface and the main side beam is H; and the thickness of the free surface is H2; and the distance from the upper surface of the water-cooled plate to the upper surface of the main side beam is H3; wherein 10mm≤H1≤100mm, 0≤H3≤80mm, 18≤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, a reinforcing rib is provided inside the secondary side beam; wherein the thickness of the reinforcing rib is T1; wherein 3mm≤T1≤7mm.

[0012] Furthermore, the distance between the edge of the water-cooling plate and the reinforcing rib is L3.

[0013] Furthermore, the distance between the edge of the water-cooling flat plate and the corner of the inner folding surface is L2; ​​and the width of the secondary side beam is L4; wherein 5mm≤L2≤L4 / 2; and 0mm≤L3≤L4 / 2.

[0014] Furthermore, the length of the lower shell assembly is PL, and the width is PW; wherein 2000mm≤PL≤2300mm, 700mm≤PW≤1200mm.

[0015] The utility model also provides a battery pack, comprising a battery and the lower shell assembly as described above; wherein the battery is arranged on the water-cooling plate.

[0016] Compared with the prior art, the utility model connects the secondary side beam and the water-cooling plate by brazing, and integrates the main side beam and the secondary side beam by stir friction welding. At the same time, by designing the inner folding surface, the secondary side beam is made into a vertically concave section, which improves the connection strength between the secondary side beam and the water-cooling plate, avoids stress concentration in the riveted connection area, and improves the rigidity of the lower shell to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0018] Figure 1 A three-dimensional diagram of the best embodiment of the lower housing assembly of the utility model;

[0019] Figure 2 For this utility model Figure 1 The enlarged structural diagram at A in the middle;

[0020] Figure 3 It is a front view structural schematic diagram of the lower housing assembly of the utility model;

[0021] Figure 4 For this utility model Figure 3 Enlarged structural diagram at B in the middle.

[0022] 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

[0023] 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.

[0024] See also Figure 1 , Figure 1 1 is a stereogram of the optimal embodiment of the lower housing assembly of the utility model. Figure 1 As shown, at least one embodiment provides a lower shell assembly, including: a water-cooled plate 1; and a water-cooled runner plate 2 fixed to 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; and a main side beam 4 is stir-friction welded on one side of the secondary side beam 3; the main side beam 4 and the secondary side beam 3 are both hollow structures. The cross-section of the main side beam 4 is rectangular, and the main side beam 4 is extruded by 6 series aluminum. The secondary side beam 3 is extruded by 3 series aluminum, and the water-cooled plate 1 is also extruded by 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. Part of the inner folding surface 34 on the secondary side beam 3 is connected to the water-cooled runner plate 2 by brazing. The concave section of the secondary side beam 3 is optimized to increase the vertical space available for the battery cell design, so as to improve the energy density of the whole package. The width of the lower shell assembly is PW and the length is PL; 2000mm≤PL≤2300mm, 700mm≤PW≤1200mm.

[0025] Please continue reading Figure 1 Combined with Figure 2 , Figure 2 For this utility model Figure 1 The enlarged structural diagram at A in the figure. Figure 1 to Figure 2 As shown, the secondary side beam 3 also has a horizontal surface 31, a welding surface 32 and a free surface 33. 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. The inner profile of the cross section of the secondary side beam 3 is a combination of a rectangle and a right-angle trapezoid. The welding surface 32 is fixedly connected to one side of the main side beam 4 by stir friction welding.

[0026] Please continue reading Figure 2 Combined with Figure 3 to Figure 4 As shown, Figure 3 This is a front view structural diagram of the lower housing assembly of the utility model. Figure 4 For this utility model Figure 3 The enlarged structural diagram at B in the figure. Figures 2 to 4 As shown, 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.

[0027] Please continue reading Figure 4 .like Figure 4As shown, the height between the welding surface 32 and the main side beam 4 is H1; the thickness of the free surface 33 is H2; and the distance from the upper surface of the water-cooling plate 1 to the upper surface of the main side beam 4 is H3; H1 is the height value of the main side beam 4, and also the height value of the welding surface 32, which will greatly affect the overall rigidity of the battery pack; if H1 is too large, the weight of the secondary side beam 3 will be too large, affecting the energy density of the whole pack; if H1 is too small, the rigidity of the main side beam 4 will be insufficient, seriously affecting the structural safety of the battery pack, where 10mm≤H1≤100mm. H3 is in the vertical direction; this value will greatly affect the available space of the battery cell in the height direction of the whole pack. Under the constraints of structural rigidity and energy density of the whole pack, 0≤H3≤80mm, 18≤H2≤H1.

[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 corner of the inner folding surface 34 is L2; ​​and the distance between the edge of the water-cooling plate 1 and the reinforcing rib 35 is L3. The secondary side beam adopts a vertical concave section to increase the H3 value as much as possible; among which 15mm≤L1≤75mm; if the overlap 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 overlap 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, so 5mm≤L2≤L4 / 2; and 0mm≤L3≤L4 / 2.

[0029] The utility model further provides a battery pack, comprising a battery and the lower housing assembly 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. At the same time, by designing the inner folding surface 34, the secondary side beam 3 is made into a vertically concave section, 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 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 housing assembly, 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 One side surface of the secondary side beam (3) is welded to the main side beam (4) by friction stir welding; The portion of the inner folded surface (34) on the secondary side beam (3) is connected to the water-cooling channel plate (2) by brazing.

2. The lower housing assembly according to claim 1, wherein: The secondary side beam (3) further comprises a horizontal surface (31), a welding surface (32) and a free surface (33); 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 plane (31).

3. The lower housing assembly according to claim 2, wherein: 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 free-standing surface (33) is H2; and The distance between the upper surface of the water-cooling plate (1) and the upper surface of the main side beam (4) is H3; wherein 10mm≤H1≤100mm, 0≤H3≤80mm, 18≤H2≤H1.

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

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

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

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

8. The lower housing assembly according to claim 7, characterized in that: The distance between the edge of the water-cooling flat plate (1) and the folded corner of the inner folded surface (34) 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 assembly according to claim 1, wherein: The length of the lower shell assembly 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 housing assembly according to any one of claims 1 to 9; The battery is arranged on the water-cooling plate (1).

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