Battery unit and manufacturing method for the same

Abstract

To provide a battery case in which a plate member is bonded to a vertical frame and a horizontal frame without being bent.SOLUTION: A battery case includes: a pair of vertical frames extending in parallel with a front-rear direction; a pair of horizontal frames extending in parallel with a right-left direction; and a plate member extending in the front-rear direction and the right-left direction. Each vertical frame and each horizontal frame are combined in a square frame shape. Each vertical frame has a vertical rib that connects an upper end and a lower end in a hollow cross section and extends in the front-rear direction. The horizontal frame has a horizontal rib that connects the upper end and the lower end in the hollow cross section and extends in the right-left direction. When a vertical frame side connecting part and a horizontal frame side connecting part are in contact with each other, the vertical rib and the horizontal rib are in contact with each other. The plate member covers at least one of each vertical frame and each horizontal frame combined in a rectangular frame shape from an up-down direction. The plate member is bonded to each vertical frame and each horizontal frame at a bonding line extending along the vertical rib and the horizontal rib so as to overlap the vertical rib and the horizontal rib in the vertical direction.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a battery unit that is arranged below a floor panel of a vehicle with battery cells housed in a battery case, and a manufacturing method thereof. [Background technology]

[0002] A battery unit 130 according to the prior art is shown in Fig. 11. The battery unit 130 has a battery case 132 that houses battery cells. The battery case 132 has a pair of vertical frames 140 that extend parallel to the front-rear direction, a pair of horizontal frames 150 that extend parallel to the left-right direction, and plate members 160 that extend in the front-rear and left-right directions. The vertical frames 140 and the horizontal frames 150 are butted against each other to combine into a rectangular frame shape that surrounds the battery cells.

[0003] The plate material 160 covers the vertical frames 140 and the horizontal frames 150, which are combined to form a rectangular frame, from at least one of the upper and lower directions. The plate material 160 is joined to the vertical frames 140 and the horizontal frames 150.

[0004] One possible method for joining the plate material 160 to the vertical frame 140 and the horizontal frame 150 is press joining. In press joining, the plate material 160 is joined to the vertical frame 140 and the horizontal frame 150 while being pressed against them. Specific examples of press joining include friction stir welding and series welding. The former, friction stir welding, is disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-159488 Summary of the Invention [Problem to be solved by the invention]

[0006] The vertical frame 140 has vertical ribs 142 that connect the upper and lower ends of the hollow cross section and extend in the front-to-rear direction. The horizontal frame 150 has horizontal ribs 152 that connect the upper and lower ends of the hollow cross section and extend in the left-to-right direction.

[0007] The vertical frame 140 and the horizontal frame 150 are butted together to form a rectangular frame. At this time, the vertical ribs 142 and the horizontal ribs 152 do not contact each other at the four corners of the battery case 132, resulting in rib-less areas N where there are no ribs.

[0008] When the plate material 160 is press-joined to the vertical frame 140 and the horizontal frame 150 in a state where the rib-free portion N has occurred, the plate material 160 cannot be supported by the vertical ribs 142 and the horizontal ribs 152, and so the plate material 160 bends. The bending of the plate material 160 is undesirable because it reduces the joining strength of the plate material 160 to the vertical frame 140 and the horizontal frame 150.

[0009] An object of the present disclosure is to join plate materials to vertical frames and horizontal frames without bending the plate materials in a battery case of a battery unit arranged below a floor panel of a vehicle. [Means for solving the problem]

[0010] A battery unit according to the present disclosure is a battery unit that is disposed below a floor panel of a vehicle with battery cells housed in a battery case, the battery case having a pair of vertical frames extending parallel to the front-rear direction, a pair of horizontal frames extending parallel to the left-right direction, and plate members extending in the front-rear direction and the left-right direction, the vertical frames and the horizontal frames being combined into a rectangular frame shape so as to surround the battery cells, the vertical frames having vertical ribs that connect upper and lower ends of the hollow cross section and extend in the front-rear direction, and the horizontal frames having vertical ribs that connect upper and lower ends of the hollow cross section and extend in the front-rear direction. and horizontal ribs extending in the left-right direction, and when the connection portions of the vertical frame to the horizontal frame on the vertical frame side and the connection portions of the horizontal frame to the vertical frame on the horizontal frame side come into contact with each other, the vertical ribs and the horizontal ribs come into contact with each other, and the plate material covers the vertical frames and the horizontal frames combined in a rectangular frame shape from at least one of the vertical and horizontal directions, and the plate material is joined to the vertical frames and the horizontal frames at joint lines that extend along the vertical ribs and the horizontal ribs so as to overlap when viewed in the vertical direction.

[0011] When the vertical frame side connection portions of the vertical frames and the horizontal frame side connection portions of the horizontal frames come into contact with each other, the vertical ribs of the vertical frames and the horizontal ribs of the horizontal frames come into contact with each other, so that the vertical ribs and the horizontal ribs extend around the entire periphery of the battery case in a rectangular frame shape without being interrupted at the four corners.

[0012] The plate members are joined to the vertical frames and horizontal frames at joining lines that extend along the vertical ribs and horizontal ribs so as to overlap each other when viewed in the up-down direction.

[0013] When the plate material is stacked on the vertical and horizontal frames, it can be joined to the vertical and horizontal frames at the joining line by pressing the plate material with a pressing tool so that it follows the vertical and horizontal ribs. When the plate material is pressed with the pressing tool, the vertical and horizontal ribs support the plate material, thereby suppressing deflection of the plate material due to press joining.

[0014] As described above, in the battery case of the battery unit disposed below the floor panel of the vehicle, the plate members can be joined to the vertical frame and the horizontal frame without being bent.

[0015] In one embodiment, the vertical frame side connection portions are formed obliquely relative to the front-rear and left-right directions, and the horizontal frame side connection portions are formed obliquely relative to the front-rear and left-right directions.

[0016] By forming the vertical frame side connection portion and the horizontal frame side connection portion at an angle, when the vertical frame side connection portion and the horizontal frame side connection portion are brought into contact with each other, it becomes easier to bring the vertical rib and the horizontal rib into contact with each other.

[0017] In one embodiment, the vertical frame side connection portion is formed in a stepped shape, and the horizontal frame side connection portion is formed in a stepped shape, and the stepped vertical frame side connection portion and the stepped horizontal frame side connection portion are engaged with each other.

[0018] By forming the vertical frame side connection portion and the horizontal frame side connection portion in a stepped shape, it becomes easier to bring the vertical ribs and horizontal ribs into contact with each other when bringing the vertical frame side connection portion and the horizontal frame side connection portion into contact with each other.

[0019] In one embodiment, the vertical frame has vertical auxiliary ribs that connect both side ends of the hollow cross section and extend in the front-to-rear direction, and the horizontal frame has horizontal auxiliary ribs that connect both side ends of the hollow cross section and extend in the left-to-right direction.

[0020] The vertical and horizontal auxiliary ribs can increase the rigidity of the vertical and horizontal frames, which is advantageous in suppressing deflection of the plate materials that occurs during press-joining.

[0021] The manufacturing method of the battery unit according to the present disclosure is a method for manufacturing the battery unit, in which the plate material is stacked on the vertical frame and the horizontal frame, and the plate material is pressed with a pressing tool so as to align with the vertical ribs and the horizontal ribs, thereby joining the plate material to the vertical frame and the horizontal frame at the joining line.

[0022] In one embodiment, the plate material is friction stir welded to the vertical frame and the horizontal frame at the joining line by rotating a rotary tool serving as the pressing tool and pressing the plate material with the rotary tool.

[0023] In friction stir welding, when a rotary tool presses a plate material, the rotary tool applies a large pressing force to the plate material. Even in such a case, the vertical ribs and the horizontal ribs support the plate material, thereby suppressing deflection of the plate material due to friction stir welding.

[0024] In one embodiment, the pressing tool includes a first electrode and a second electrode, and the first electrode and the second electrode are arranged side by side on the plate material along the vertical ribs and the horizontal ribs, and current is passed through the first electrode and the second electrode to weld the plate material to the vertical frame and the horizontal frame at the joining line. [Effects of the Invention]

[0025] According to the present disclosure, in a battery case of a battery unit arranged below a floor panel of a vehicle, plate materials can be joined to vertical frames and horizontal frames without bending. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a top view showing the structure of the vehicle body of a vehicle according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the structure of the vehicle body of the vehicle according to the first embodiment. [Figure 3]FIG. 3 shows the battery unit according to the first embodiment. [Figure 4] FIG. 4 shows the battery case according to the first embodiment. [Figure 5] FIG. 5 shows the internal structure of the vertical frame and the internal structure of the horizontal frame according to the first embodiment. [Figure 6] FIG. 6 shows the connection between the vertical frame and the horizontal frame according to the first embodiment. [Figure 7] FIG. 7 shows joining of plate materials to the vertical frame and horizontal frame according to the first embodiment. [Figure 8] FIG. 8 shows a method for manufacturing the battery unit according to the first embodiment. [Figure 9] FIG. 9 shows the connection between the vertical frame and the horizontal frame according to the second embodiment. [Figure 10] FIG. 10 shows a method for manufacturing a battery unit according to the third embodiment. [Figure 11] FIG. 11 shows a battery unit according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0028] First Embodiment The battery unit 30 of vehicle A according to the first embodiment will be described. In the following description, the front-rear direction, left-right direction, and up-down direction are based on vehicle A. In each drawing, these directions are indicated by arrows. The front-rear direction is the direction of travel of vehicle A, and is indicated by X. The left-right direction is the width direction of vehicle A, and is indicated by Y. The up-down direction is the height direction of vehicle A, and is indicated by Z.

[0029] (vehicle) FIG. 1 shows a top view of the structure of a body 1 of vehicle A. FIG. 2 shows a perspective view of the structure of the body 1 of vehicle A as seen from the direction of arrow II in FIG. 1. Vehicle A has, as components constituting the body 1, a bumper beam 2, a shroud upper member 3, a pair of apron members 4, a pair of front side frames 5, a pair of side sills 6, a dash panel 7, a floor panel 8, and a rear side frame 9. Vehicle A has a torque box 10, a suspension housing 11, and a crash can 12. Vehicle A has a battery unit 30.

[0030] Vehicle A is an electric vehicle, and is driven by a motor. Although not shown, the motor is mounted in a front space 1a provided at the front of the vehicle body 1. A passenger compartment 1b is formed in the middle of the vehicle body 1. A floor panel 8 is provided in the middle of the vehicle body 1. The floor panel 8 is substantially rectangular when viewed vertically, and extends in the front-to-rear and left-to-right directions. The floor panel 8 forms the floor surface of the passenger compartment 1b.

[0031] Vehicle A is equipped with a battery unit 30. The battery unit 30 is a power source that drives a motor for propelling vehicle A. As shown by the dashed line in FIG. 1 , the battery unit 30 is disposed below the floor panel 8 of vehicle A so as to extend along the floor panel 8.

[0032] The battery unit 30 has a rectangular appearance when viewed from above, which is substantially the same as the floor panel 8. The battery unit 30 will be described later.

[0033] As shown in Fig. 2, the front space 1a and the passenger compartment 1b are separated by a dash panel 7. The dash panel 7 extends in the vertical and horizontal directions.

[0034] A pair of side sills 6 are provided on both the left and right sides of the middle portion of the vehicle body 1. The side sills 6 are made of pillar-shaped members and have excellent strength and rigidity. The pair of side sills 6 extend parallel to each other in the front-rear direction along the edge portions 8a on both left and right sides of the floor panel 8. The pair of side sills 6, together with the floor panel 8, constitute the vehicle body 1.

[0035] A pair of rear side frames 9 are connected to the rear ends of the pair of side sills 6. The pair of rear side frames 9 extend rearward. A rear floor panel 9a, which is continuous with the floor panel 8, is provided between the pair of rear side frames 9.

[0036] As shown in Figures 1 and 2, a pair of front side frames 5 extend forward, spaced apart in the left-right direction, from in front of the floor panel 8. The pair of front side frames 5, together with the floor panel 8, form the vehicle body 1. When viewed in the vertical direction, the pair of front side frames 5 are slightly inclined so that they widen in the left-right direction as they move forward. The front side frames 5 are made up of columnar members with a rectangular cross section.

[0037] The front side frame 5 is joined to the front end of the floor panel 8 and the torque box 10 .

[0038] A suspension housing 11 is provided in front of each of the left and right ends of the dash panel 7. The lower end of the suspension housing 11 is connected to the front side frame 5. The upper end of the suspension housing 11 is connected to the apron member 4.

[0039] The apron members 4 extend forward from the outside of the suspension housing 11. The apron members 4 are curved so that they turn inward in the left-right direction as they extend forward. The front ends of the pair of apron members 4 are connected by a shroud upper member 3 that extends in the left-right direction.

[0040] A bumper beam 2 extending in the left-right direction is disposed below and forward of the shroud upper member 3. Front ends of the front side frames 5 are connected to both left-right ends of the bumper beam 2 via crash cans 12.

[0041] (battery unit) Fig. 3 is a perspective view of the battery unit 30. Fig. 4 is a perspective view of the battery case 32. The battery unit 30 has a plurality of battery cells 31 and a battery case 32. The plurality of battery cells 31 are housed in the battery case 32. The battery unit 30 is disposed below the floor panel 8 of the vehicle A with the battery cells 31 housed in the battery case 32.

[0042] The battery cells 31 are composed of lithium ion batteries or the like. All of the battery cells 31 are electrically connected and can output a predetermined high voltage. The battery cells 31 are formed in a rectangular block shape (cuboid shape) in consideration of loading efficiency into the battery case 32. In this example, 12 battery cells 31 are arranged inside the battery case 32 so that four are arranged in the left-right direction and three are arranged in the front-rear direction and are closely spaced.

[0043] The battery case 32 has a pair of vertical frames 40 , a pair of horizontal frames 50 , and a plate member 60 .

[0044] The pair of vertical frames 40 are spaced apart in the left-right direction and extend parallel to the front-rear direction. The pair of horizontal frames 50 are spaced apart in the front-rear direction and extend parallel to the front-rear direction. In the battery case 32, the vertical frames 40 and the horizontal frames 50 are combined to form a square frame when viewed in the up-down direction so as to surround the battery cells 31. In detail, the battery case 32 is formed in a rectangular frame shape with its long sides in the front-rear direction and its short sides in the left-right direction. The vertical frames 40 are fixed to the side sills 6.

[0045] Hereinafter, the side toward the inside of the battery case 32 in the front-to-back direction (left-to-right direction) (the side where the battery cells 31 are arranged) may be referred to as the inner side in the front-to-back direction (left-to-right direction), and the side toward the outside of the battery case 32 in the front-to-back direction (left-to-right direction) (the side where the battery cells 31 are not arranged) may be referred to as the outer side in the front-to-back direction (left-to-right direction).

[0046] The plate material 60 has a thickness in the up-down direction and extends in the front-rear and left-right directions. The plate material 60 covers the vertical frames 40 and horizontal frames 50, which are combined to form a rectangular frame, from at least one of the up-down direction. In this example, the plate material 60 covers the vertical frames 40 and horizontal frames 50, which are combined to form a rectangular frame, from below (the bottom side). The plate material 60 forms the bottom surface of the battery case 32.

[0047] The plate material 60 is arranged to cover from below the lower parts of the vertical frames 40, the lower parts of the horizontal frames 50, and the space partitioned by the vertical frames 40 and the horizontal frames 50. Although not shown, a lid material that covers the upper part of the battery case 32 may be provided.

[0048] Fig. 5 shows the internal structure of the vertical frame 40 and the internal structure of the horizontal frame 50. Fig. 5 is a cross-sectional view taken along line V in Fig. 4. In Fig. 5, the reference numerals relating to the vertical frame 40 are shown without parentheses, and the reference numerals relating to the horizontal frame 50 are shown with parentheses.

[0049] The vertical frame 40 is made of square pipes. A cross section of the vertical frame 40 as viewed in the longitudinal direction (front-to-back direction) is formed to be hollow. The vertical frame 40 has a hollow cross section 41. The hollow cross section 41 of the vertical frame 40 is formed in the shape of a square frame.

[0050] The vertical frame 40 has a vertical rib 42. The vertical rib 42 connects an upper end 41a and a lower end 41b of the hollow cross section 41 of the vertical frame 40. The vertical rib 42 extends in the front-rear direction from one end to the other end of the vertical frame 40.

[0051] The vertical frame 40 has vertical auxiliary ribs 43. The vertical auxiliary ribs 43 connect both side ends 41c (upper and lower central portions) of the hollow cross section 41 of the vertical frame 40. The vertical auxiliary ribs 43 extend in the front-to-rear direction from one end to the other end of the vertical frame 40. In the hollow cross section 41 of the vertical frame 40, the vertical ribs 42 and the vertical auxiliary ribs 43 intersect with each other in a crisscross shape.

[0052] The horizontal frame 50 is made of square pipes. A cross section of the horizontal frame 50 viewed in the longitudinal direction (left-right direction) is formed to be hollow. The horizontal frame 50 has a hollow cross section 51. The hollow cross section 51 of the horizontal frame 50 is formed in the shape of a square frame.

[0053] The horizontal frame 50 has a horizontal rib 52. The horizontal rib 52 connects an upper end 51a and a lower end 51b of the hollow cross section 51 of the horizontal frame 50. The horizontal rib 52 extends in the left-right direction from one end to the other end of the horizontal frame 50.

[0054] The horizontal frame 50 has horizontal auxiliary ribs 53. The horizontal auxiliary ribs 53 connect both side ends 51c (upper and lower central portions) of the hollow cross section 51 of the horizontal frame 50. The horizontal auxiliary ribs 53 extend in the left-right direction from one end to the other end of the horizontal frame 50. In the hollow cross section 51 of the horizontal frame 50, the horizontal ribs 52 and the horizontal auxiliary ribs 53 intersect with each other in a crisscross shape.

[0055] The vertical frame 40 and the horizontal frame 50 are formed by extruding aluminum, for example.

[0056] (Connection between vertical and horizontal frames) 6 shows the connection between the vertical frame 40 and the horizontal frame 50. The vertical frame side connection portion 44 of the vertical frame 40 to the horizontal frame 50 is formed obliquely with respect to the front-to-rear and left-to-right directions. The vertical frame side connection portion 44 is the portion that connects the vertical frame 40 to the horizontal frame 50.

[0057] The horizontal frame side connection portions 54 of the horizontal frame 50 to the vertical frame 40 are formed obliquely with respect to the front-rear and left-right directions. The horizontal frame side connection portions 54 are portions that connect the horizontal frame 50 to the vertical frame 40.

[0058] When the vertical frame side connection portions 44 of the vertical frames 40 and the horizontal frame side connection portions 54 of the horizontal frames 50 come into contact with each other, the vertical ribs 42 of the vertical frames 40 and the horizontal ribs 52 of the horizontal frames 50 come into contact with each other.

[0059] The vertical ribs 42 and horizontal ribs 52 extend around the entire periphery of the square frame without being interrupted at the four corners of the battery case 32.

[0060] (Joining of boards to vertical and horizontal frames) Figure 7 shows the joining of plate material 60 to the vertical frame 40 and horizontal frame 50. Note that in Figure 7, the image is turned upside down (top and bottom are swapped) for ease of understanding. The left view of Figure 7 shows the state where plate material 60 has been removed, and the right view of Figure 7 shows the state where plate material 60 has been attached.

[0061] The plate material 60 covers the vertical frame 40 and the horizontal frame 50, which are combined to form a rectangular frame, from at least one of the upper and lower directions.

[0062] The plate material 60 is joined to the vertical frame 40 and the horizontal frame 50 at the joining line L. The joining line L extends along the vertical rib 42 and the horizontal rib 52 so as to overlap when viewed in the up-down direction.

[0063] The joining lines L (overlapping the vertical ribs 42 and the horizontal ribs 52) extend around the entire periphery of the battery case 32 in a rectangular frame shape without being interrupted at the four corners of the battery case 32.

[0064] (Battery unit manufacturing method) Fig. 8 shows a manufacturing method of the battery unit 30. Fig. 8 is a cross-sectional view taken along line VIII in Fig. 7. In Fig. 8, the reference numerals relating to the vertical frame 40 are shown without parentheses, and the reference numerals relating to the horizontal frame 50 are shown with parentheses. The manufacturing method of the battery unit 30 is a method for manufacturing the battery unit 30 described above.

[0065] With the plate material 60 stacked on the vertical frame 40 and the horizontal frame 50, the plate material 60 is pressed in the vertical direction along the vertical ribs 42 and the horizontal ribs 52 with a pressing tool T, thereby joining the plate material 60 to the vertical frame 40 and the horizontal frame 50 at the joining line L.

[0066] Specifically, while rotating the rotary tool Ta as the pressing tool T, the rotary tool Ta presses the plate material 60 in the vertical direction, thereby friction stir welding the plate material 60 to the vertical frame 40 and the horizontal frame 50 at the joining line L.

[0067] Friction stir welding (FSW) is a method of joining base materials without melting them by rotating a rotating tool Ta, which is harder than the base materials, and pressing the rotating tool Ta into the base materials. The rotating tool Ta is rod-shaped and extends in the vertical direction. The rotating tool Ta rotates around a rotation axis that also extends in the vertical direction.

[0068] Friction stir welding is a type of solid-state welding. In friction stir welding, the frictional heat generated by the rotation of the rotary tool Ta reduces the deformation resistance of the plate material 60 and the vertical and horizontal frames 40 and 50. In friction stir welding, the plate material 60 and the vertical and horizontal frames 40 and 50 are plastically flowed and stirred by the movement of the rotary tool Ta. In friction stir welding, the plate material 60 and the vertical and horizontal frames 40 and 50 are joined together as a single unit.

[0069] In friction stir welding, a strong pressing force is applied in the vertical direction to the plate material 60 (which is stacked on the vertical frame 40 and the horizontal frame 50).

[0070] (Action and effect) When the vertical frame side connection portions 44 of the vertical frames 40 and the horizontal frame side connection portions 54 of the horizontal frames 50 come into contact with each other, the vertical ribs 42 of the vertical frames 40 and the horizontal ribs 52 of the horizontal frames 50 come into contact with each other. As a result, the vertical ribs 42 and the horizontal ribs 52 extend around the entire periphery of the battery case 32 in a rectangular frame shape without being interrupted at the four corners of the battery case 32.

[0071] The plate material 60 is joined to the vertical frame 40 and the horizontal frame 50 at the joining line L. The joining line L extends along the vertical rib 42 and the horizontal rib 52 so as to overlap when viewed in the up-down direction.

[0072] With the plate material 60 stacked on the vertical frames 40 and the horizontal frames 50, the plate material 60 can be joined to the vertical frames 40 and the horizontal frames 50 at the joining line L by pressing the plate material 60 in the vertical direction with the pressing tool T so that it follows the vertical ribs 42 and the horizontal ribs 52. When the plate material 60 is pressed in the vertical direction with the pressing tool T, the vertical ribs 42 and the horizontal ribs 52 support the plate material 60. This makes it possible to suppress deflection of the plate material 60 due to press joining.

[0073] As described above, in the battery case 32 of the battery unit 30 disposed below the floor panel 8 of the vehicle A, the plate material 60 can be joined to the vertical frame 40 and the horizontal frame 50 without being bent.

[0074] By forming the vertical frame side connection portion 44 and the horizontal frame side connection portion 54 at an angle, when the vertical frame side connection portion 44 and the horizontal frame side connection portion 54 are brought into contact with each other, the vertical rib 42 and the horizontal rib 52 can be easily brought into contact with each other.

[0075] The vertical auxiliary ribs 43 and the horizontal auxiliary ribs 53 can increase the rigidity of the vertical frames 40 and the horizontal frames 50. This is advantageous in suppressing deflection of the plate material 60 due to press-joining.

[0076] In friction stir welding, when the rotary tool Ta presses the plate material 60 in the vertical direction, the rotary tool Ta applies a large pressing force to the plate material 60. Even in such a case, the vertical ribs 42 and the horizontal ribs 52 support the plate material 60, thereby suppressing deflection of the plate material 60 due to friction stir welding.

[0077] Second Embodiment A battery unit 30 according to a second embodiment will be described. In the following description, the same components as those in the above embodiment will be assigned the same reference numerals, and detailed description will be omitted. Figure 9 shows the connection between the vertical frame 40 and the horizontal frame 50 according to the second embodiment.

[0078] The vertical frame side connection portions 44 of the vertical frames 40 are formed in a stepped shape. The horizontal frame side connection portions 54 of the horizontal frames 50 are also formed in a stepped shape. The stepped vertical frame side connection portions 44 of the vertical frames 40 and the stepped horizontal frame side connection portions 54 of the horizontal frames 50 are engaged with each other.

[0079] When the vertical frame side connection portions 44 of the vertical frames 40 and the horizontal frame side connection portions 54 of the horizontal frames 50 come into contact with each other, the vertical ribs 42 of the vertical frames 40 and the horizontal ribs 52 of the horizontal frames 50 come into contact with each other.

[0080] The vertical ribs 42 and horizontal ribs 52 extend around the entire periphery of the battery case 32 in a rectangular frame shape without being interrupted at the four corners of the battery case 32.

[0081] Other configurations are the same as those of the first embodiment. According to this embodiment, the same effects as those of the first embodiment can be obtained. Furthermore, by forming the vertical frame side connecting portions 44 and the horizontal frame side connecting portions 54 in a stepped shape, when the vertical frame side connecting portions 44 and the horizontal frame side connecting portions 54 are brought into contact with each other, the vertical ribs 42 and the horizontal ribs 52 can be easily brought into contact with each other.

[0082] Third Embodiment A method for manufacturing a battery unit 30 according to the third embodiment will be described. In the following description, the same components as those in the above embodiment will be denoted by the same reference numerals, and detailed description will be omitted. Figure 10 shows the method for manufacturing a battery unit 30 according to the third embodiment.

[0083] In this embodiment, the plate material 60 is joined to the vertical frame 40 and the horizontal frame 50 by series welding.

[0084] The pressing tool T includes a first electrode T1 and a second electrode T2. In a state in which the first electrode T1 and the second electrode T2 are arranged side by side on the plate material 60 along the vertical ribs 42 and the horizontal ribs 52, a current I is passed through the plate material 60 by the first electrode T1 and the second electrode T2, thereby welding the plate material 60 to the vertical frame 40 and the horizontal frame 50 at the joining line L.

[0085] The first electrode T1 and the second electrode T2 serving as the pressing tool T press the plate material 60 (which is stacked on the vertical frame 40 and the horizontal frame 50) in the vertical direction. The pressing force of the first electrode T1 and the second electrode T2 is smaller than the pressing force of the rotary tool Ta during friction stir welding.

[0086] <Other embodiments> Although the present disclosure has been described above with reference to preferred embodiments, such description is not limiting, and it goes without saying that various modifications, substitutions, or combinations are possible.

[0087] In the above embodiment, the plate material 60 covers the vertical frames 40 and horizontal frames 50, which are combined to form a rectangular frame, from below (bottom side), but this is not limited to this. The plate material 60 may also cover the vertical frames 40 and horizontal frames 50, which are combined to form a rectangular frame, from above. Furthermore, two plate materials 60 may cover the vertical frames 40 and horizontal frames 50, which are combined to form a rectangular frame, from both the top and bottom directions (above and below). In other words, it is sufficient that the plate material 60 covers the vertical frames 40 and horizontal frames 50, which are combined to form a rectangular frame, from at least one of the top and bottom directions.

[0088] The joining lines L may be interrupted along the way as long as they overlap the vertical ribs 42 and the horizontal ribs 52 when viewed in the up-down direction. For example, the joining lines L may be provided intermittently in the shape of a rectangular frame so as to overlap the vertical ribs 42 and the horizontal ribs 52 when viewed in the up-down direction.

[0089] In the above embodiment, the plate material 60 is joined to the vertical frame 40 and the horizontal frame 50 by friction stir welding or series welding, but this is not limiting. For example, the plate material 60 may be joined to the vertical frame 40 and the horizontal frame 50 by ordinary resistance welding (a method in which the plate material 60 is sandwiched between an upper electrode and a lower electrode). Furthermore, the plate material 60 may be joined to the vertical frame 40 and the horizontal frame 50 by other joining methods. [Industrial Applicability]

[0090] The present disclosure is applicable to battery units and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0091] X Anteroposterior direction Y left / right direction Z vertical direction T Pressing Tool Ta Rotation Tool T1 1st electrode T2 2nd electrode L Joint Line I current Vehicle A 1. Body 1a Front space 1b Cabin 2 bumper beams 3 Shroud upper member 4 Apron Members 5 Front side frame 6 Side sill 7 Dash Panel 8 Floor Panels 8a Edge 9 Rear side frame 9a Rear floor panel 10 Torque box 11 Suspension housing 12 Crush Can 30 Battery Unit 31 battery cells 32 Battery case 40 vertical frame 41 Hollow section 41a top end 41b Bottom end 41c both ends 42 Vertical ribs 43 Vertical support rib 44 Vertical frame side connection part 50 horizontal frame 51 Hollow section 51a top end 51b Bottom end 51c both ends 52 Horizontal rib 53 Horizontal support rib 54 Horizontal frame side connection part 60 Board material 130 Battery Unit 132 Battery case 140 vertical frame 142 Vertical rib 150 horizontal frame 152 horizontal rib 160 Board material N Rib-less area

Claims

1. A battery unit that is disposed under a floor panel of a vehicle with battery cells housed in a battery case, The battery case includes: A pair of vertical frames extending parallel to each other in the front-rear direction; A pair of horizontal frames extending parallel to each other in the left-right direction; a plate member extending in the front-rear direction and the left-right direction, The vertical frame and the horizontal frame are combined to form a rectangular frame so as to surround the battery cell, The vertical frame has a vertical rib that connects the upper end and the lower end of the hollow cross section and extends in the front-rear direction, The horizontal frame has a horizontal rib that connects the upper end and the lower end of the hollow cross section and extends in the left-right direction, When the vertical frame side connection portion of the vertical frame to the horizontal frame and the horizontal frame side connection portion of the horizontal frame to the vertical frame come into contact with each other, the vertical rib and the horizontal rib come into contact with each other, The plate material covers the vertical frames and the horizontal frames combined in a rectangular frame shape from at least one of the upper and lower directions, The plate material is joined to the vertical frame and the horizontal frame at a joining line that extends along the vertical rib and the horizontal rib so as to overlap when viewed in the up-down direction.

2. The vertical frame side connection portion is formed obliquely with respect to the front-rear direction and the left-right direction, The horizontal frame side connection portion is formed obliquely with respect to the front-rear direction and the left-right direction. The battery unit according to claim 1 .

3. The vertical frame side connection portion is formed in a stepped shape, The horizontal frame side connection portion is formed in a stepped shape, The battery unit according to claim 1 , wherein the stepped vertical frame side connection portions and the stepped horizontal frame side connection portions are engaged with each other.

4. The vertical frame has a vertical auxiliary rib that connects both side ends of the hollow cross section and extends in the front-rear direction, The battery unit according to claim 1 , wherein the horizontal frame has a horizontal auxiliary rib that connects both side ends of the hollow cross section and extends in the left-right direction.

5. A method for manufacturing a battery unit according to any one of claims 1 to 3, comprising the steps of: A method for manufacturing a battery unit, in which the plate material is stacked on the vertical frame and the horizontal frame, and the plate material is pressed with a pressing tool along the vertical ribs and the horizontal ribs, thereby joining the plate material to the vertical frame and the horizontal frame at the joining line.

6. 6. The method for manufacturing a battery unit according to claim 5, wherein the plate material is friction stir welded to the vertical frame and the horizontal frame at the joining line by rotating a rotary tool as the pressing tool and pressing the plate material with the rotary tool.

7. the pressing tool includes a first electrode and a second electrode; 6. A method for manufacturing a battery unit as described in claim 5, wherein the first electrode and the second electrode are arranged side by side on the plate material along the vertical ribs and the horizontal ribs, and current is passed through the plate material by the first electrode and the second electrode, thereby welding the plate material to the vertical frame and the horizontal frame at the joining line.

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