Vehicle battery case

Abstract

To provide a vehicle battery case that can be appropriately painted even when other parts are attached in surface contact with each other. [Solution] The battery case 12 of the battery 10 has an upper case 20 and a lower case 22 stacked on top of each other to form an internal space for accommodating the battery pack. A flat portion 52 of a frame component 42 is attached to the lower case 22 in surface contact with the underside of a bottom plate 24, and a recess 58 is formed in the bottom plate 24, extending from a contact area 56 where the flat portion 52 is in surface contact to a non-contact area within a notch 54 of the frame component 42. As a result, even when the frame component 42 is attached to the lower case 22, coating liquid can flow around the contact area, preventing uneven coating such as a thin coating or exposure of the base material, and suppressing the occurrence and progression of rust.

Description

[Technical Field]

[0001] The present invention relates to a vehicle battery case. [Background technology]

[0002] Patent Document 1 describes a battery pack installed on the floor of a vehicle. The battery pack has multiple battery cells arranged in a battery pack case, which has a lower case in which the multiple battery cells are arranged side by side, and an upper case that isolates the space in the lower case in which the battery cells are arranged from the surrounding area. The lower case of the battery pack case is fixed to the floor of the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-123227 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, battery pack cases (battery cases) use steel plates or the like for the lower and upper cases, and the lower and upper cases are subjected to electrodeposition coating or the like to improve rust resistance. Electrodeposition coating involves, for example, immersing the lower and upper cases as the objects to be coated in an electrodeposition coating solution that uses an electrically charged cationic resin as the paint, and applying an electrodeposition voltage according to preset electrodeposition conditions between the object to be coated (cathode) as one electrode (cathode) and the other electrode (anode) placed in the electrodeposition coating solution. As a result, the formation of a coating film (resin coating film) containing the cationic resin on the surface of the object to be coated, such as the lower case, suppresses the occurrence of rust and the like.

[0005] Various components are attached to battery cases, such as those used to secure the battery case to the vehicle body, and the upper and lower cases of the battery case are sometimes painted while these components are attached. In this case, if, for example, another component is in surface contact with the outer surface of the lower case, the paint solution may not penetrate the contact surface with the other component, resulting in an inadequate paint film or exposure of the base material. If an inadequate paint film is formed on the outer surface of the battery case or if the base material is exposed, rust may form or the existing rust may progress, leaving room for improvement in the paint (paint film formation) process.

[0006] The present invention has been made in consideration of the above-mentioned facts, and aims to provide a vehicle battery case that can be appropriately painted even if the mounting parts are attached in surface contact. [Means for solving the problem]

[0007] In order to achieve the above object, a vehicle battery case according to a first aspect includes a case body that houses a battery module having a plurality of stacked battery cells in an internal space, and an attachment part that is attached in face-to-face contact with the outer surface of the case body and painted together with the case body, and includes a groove-shaped recess formed on the outer surface of the case body that extends from a contact area that is in face-to-face contact when the attachment part is attached to the outer surface of the case body to a non-contact area of ​​the attachment part.

[0008] In a vehicle battery case according to a first aspect, a battery module in which a plurality of battery cells are stacked is housed in the internal space of a case body. Mounting components are attached to the case body in surface contact with the outer surface. The case body is then painted with the mounting components attached.

[0009] Here, a groove-shaped recess is formed on the outer surface of the case body, and the recess is formed so as to extend from the contact area where the mounting part is attached and is in surface contact with the mounting part to the non-contact area of ​​the mounting part.

[0010] Therefore, on the outer surface of the case body, the paint that penetrates into the recesses in the non-contact areas flows down the recesses to reach the contact areas, so that a coating film can be properly formed even in the contact areas, thereby suppressing the occurrence and progression of rust on the outer surface of the case body.

[0011] A vehicle battery case according to a second aspect is the same as that according to the first aspect, in which the case main body includes a lower case on which the battery module is placed and an upper case that covers the lower case and forms an internal space between the lower case and the upper case in which the battery module is accommodated, and the recess is formed in the lower case.

[0012] In a vehicle battery case according to a second aspect, the case body includes an upper case and a lower case, and the recess is formed in the lower case. This allows the lower case to be appropriately painted even when an attachment part for supporting the case body on the vehicle body is attached to the lower case, effectively preventing rust from occurring or progressing on the lower case.

[0013] A vehicle battery case according to a third aspect includes the second aspect, wherein the recess is formed at a vehicle front end of the lower case.

[0014] In a vehicle battery case according to a third aspect, a recess is formed in the vehicle front end of the lower case, which improves the rigidity of the vehicle front portion of the lower case and prevents deformation even if the lower case receives a load from the vehicle front in the event of a vehicle emergency. [Effects of the Invention]

[0015] According to this aspect of the present invention, even when an attachment part is attached in surface contact with the outer surface of the case body, the penetration of paint into the contact surface can be promoted. As a result, an appropriate coating film can be formed on the case body without exposing the base material, and rust on the case body can be suppressed, and even if rust does occur, its progression can be suppressed. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing a schematic configuration of a battery according to an embodiment of the present invention. [Figure 2] FIG. 4 is a plan view showing a main part of the lower case as viewed from below. [Figure 3] FIG. 2 is a perspective view showing an outline of a main part of the lower case, viewed obliquely from above and rear on the left side. [Figure 4] FIG. 10 is a plan view showing a main part of a lower case according to a modified example, as viewed from below. DETAILED DESCRIPTION OF THE INVENTION

[0017] A vehicle battery case according to an embodiment of the present invention will be described in detail below with reference to the drawings. The vehicle battery case is mounted on a vehicle for use. 1 is a perspective view showing a schematic configuration of a battery 10 according to this embodiment. In the drawing, the front side of the vehicle is indicated by an arrow FR, the right side in the vehicle width direction is indicated by an arrow HR, and the upward direction is indicated by an arrow UP.

[0018] The battery 10 is mounted, for example, on a vehicle (not shown) equipped with an electric motor as a driving source for traveling, and outputs DC power applicable to driving the electric motor. Vehicles in which the battery 10 is mounted include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs).

[0019] 1, the battery 10 includes a battery case 12 as a vehicle battery case and case body according to this embodiment, and a battery pack 14 housed in the battery case 12. The battery case 12 is disposed below a floor panel as the floor of the vehicle and above an undercover, and is attached to the vehicle body (both not shown).

[0020] The battery case 12 includes an upper case 20 and a lower case 22, which are opposed to each other with the upper case 20 on the upper side and the lower case 22 on the lower side. Fig. 2 shows a plan view (rear view) of the main part of the lower case 22 as viewed from below, and Fig. 3 shows a schematic perspective view of the main part of the lower case 22 as viewed diagonally from above and to the left rear.

[0021] 1 to 3, the lower case 22 is made of a steel plate or the like and includes a bottom plate 24 that is generally rectangular in plan view and has a flat back surface. The lower case 22 also has a peripheral wall 26 that stands upright around the periphery of the bottom plate 24, and the peripheral wall 26 has a flange portion 28 that is bent at an upper portion outward from the lower case 22 and extends around substantially the entire periphery. The bottom plate 24, peripheral wall 26, and flange portion 28 of the lower case 22 are integrally formed, and the lower case 22 is generally tray-shaped (or tub-shaped).

[0022] The upper case 20 is made of a steel plate or the like and includes a top plate 30 that is generally rectangular in plan view. The upper case 20 has a peripheral wall 32 that protrudes downward from the periphery of the top plate 30, and the tip (lower end) of the peripheral wall 32 is folded outward around substantially the entire periphery to form a flange 34. The top plate 30, peripheral wall 32, and flange 34 of the upper case 20 are integrally formed.

[0023] The battery case 12 is assembled after the upper case 20 and the lower case 22 have been painted and anti-rust treated in advance. At this time, the battery case 12 is stacked with the flange portion 34 of the upper case 20 and the flange portion 28 of the lower case 22 facing each other. The battery case 12 is assembled by fastening the flange portion 34 of the upper case 20 and the flange portion 28 of the lower case 22 together using fastening means such as bolts and nuts, and the internal space is sealed from the surroundings (not shown).

[0024] In the battery case 12, the boundary between the top plate 30 and the peripheral wall 32 in the upper case 20, and the boundary between the bottom plate 24 and the peripheral wall 26 in the lower case 22, etc. are chamfered.

[0025] In the battery 10, a battery pack 14 composed of one or more battery modules 16 is housed in the internal space of the battery case 12. The battery modules 16 are arranged in an array within the battery case 12, and are covered from the top and bottom by a bottom plate 24 and a top plate 30, and are surrounded by a peripheral wall 26 and a peripheral wall 32. This allows the battery case 12 to function as a battery pack case in which the battery pack 14 is housed.

[0026] A plurality of battery cells (not shown) are stacked in the battery module 16. In the battery 10, for example, a plurality of battery modules 16 are connected in parallel or series, and the battery 10 outputs DC power of a required voltage during discharge. Furthermore, the battery 10 charges each of the plurality of battery cells of the battery module 16 by inputting DC power of a required voltage. Note that the battery case 12 may be configured to accommodate one battery module 16, not limited to multiple battery modules 16, or may be configured to accommodate one or more hydrogen tanks used for fuel cells in addition to the battery modules 16.

[0027] Meanwhile, a support frame 40 including other parts (members) is attached to the battery case 12, and the battery case 12 is attached to the vehicle body via the support frame 40. In this embodiment, the support frame 40 is attached to the lower case 22, and the lower case 22 is attached to the vehicle body via the support frame 40. The support frame 40 also includes mounting parts made of steel plate, and the support frame 40 can be painted together with the lower case 22 in a state where the mounting parts made of steel plate are attached to the lower case 22.

[0028] The support frame 40 is formed, for example, by connecting a plurality of components to form a rectangular frame shape in a plan view, and is opposed to the peripheral edge of the bottom plate 24 on the underside of the lower case 22. The support frame 40 is also attached, for example, to straddle the bottom plate 24 and the peripheral wall 26.

[0029] This support frame 40 includes a frame component 42 that is in surface contact with the underside of the bottom plate 24 of the lower case 22 as an attachment component that is separate from the components that make up the battery case 12 and is attached in surface contact with the outer surface of the battery case 12.

[0030] The lower case 22 (battery case 12) has four corners 44. In this embodiment, as an example, the frame component 42 is described as being attached to one of the four corners 44, a corner 44RF on the front side of the vehicle and on the right side in the vehicle width direction, and a corner 44LF on the front side of the vehicle and on the left side in the vehicle width direction. In this embodiment, the corner 44RF is mainly described, and a description of the corner 44LF is omitted. Note that the frame component 42 may also be attached to a corner 44RB on the rear side of the vehicle and on the right side in the vehicle width direction, and a corner 44LB on the rear side of the vehicle and on the left side in the vehicle width direction.

[0031] 2, the frame component 42 is formed with a support portion 46 that faces the underside of the bottom plate 24 of the lower case 22, and a protruding portion 48 that is located outside the bottom plate 24 (outside the bottom plate 24 of the lower case 22). The frame component 42 also includes a connecting portion 50 that faces the outer surface of the peripheral wall 26 of the lower case 22, and the connecting portion 50 of the frame component 42 connects the support portion 46 and the protruding portion 48 together to form a single unit.

[0032] The support portion 46 of the frame component 42 is provided with a flat portion 52 that comes into surface contact with the underside of the bottom plate 24. The flat portion 52 also has a notch 54 formed in the middle in the front-to-rear direction, which is cut out from the left side to the right side in the vehicle width direction. In Fig. 2, the outline (outline) of the flat portion 52 is indicated by a two-dot chain line.

[0033] On the other hand, the bottom plate 24 of the lower case 22 has a contact area 56 (the area hatched with a dashed line in FIG. 2 ) that comes into surface contact with the flat portion 52 of the frame component 42. The bottom plate 24 has a recess 58 formed in this contact area 56. The recess 58 is groove-shaped and opens on the back surface of the bottom plate 24. One end of the contact area 56 is located on the corner 44RF side, and the other end extends outside the contact area 56. The end of the recess 58 opposite the corner 44RF side reaches the cutout 54 of the frame component 42. As a result, the recess 58 is formed in the bottom plate 24 from a position corresponding to the cutout 54 of the support portion 46 toward the corner 44RF, and the recess 58 is inclined with respect to both the front-to-rear direction and the width direction of the vehicle so as to move toward the right in the width direction as it approaches the front of the vehicle.

[0034] 3, in the lower case 22, the recess 58 is formed, so that a bead portion 60 is formed to protrude from the upper surface (the surface opposite the lower surface, the surface facing the interior space) of the bottom plate 24. The bead portion 60 protrudes from the upper surface of the bottom plate 24 and extends along the recess 58. That is, the bead portion 60 is formed on the upper surface of the bottom plate 24 so as to extend from the corner 44RF side toward the rear of the vehicle and toward the left side in the vehicle width direction (inward in the vehicle width direction), similar to the recess 58.

[0035] The bottom plate 24 has a recess 58 formed on one surface side (lower surface side) in the thickness direction, which reduces the thickness and causes a decrease in strength. Here, the bottom plate 24 has a protruding bead portion 60 formed on the other surface side (upper surface side) in the thickness direction to compensate for the change in thickness caused by the formation of the recess 58. In the lower case 22, the formation of the bead portion 60 prevents the thickness of the bottom plate 24 from being reduced by the recess 58, which would otherwise cause a decrease in strength in the thickness direction of the bottom plate 24.

[0036] The recessed portion 58 and the bead portion 60 correspond to the frame component 42 attached to the corner portion 44LF, and are formed in the vicinity of the corner portion 44LF of the bottom plate 24 (not shown). In this case, the recessed portion 58 and the bead portion 60 are formed so as to extend inward in the vehicle width direction (to the right in the vehicle width direction) from the corner portion 44LF toward the rear of the vehicle.

[0037] Next, the operation of this embodiment will be described. The battery 10 is provided with a battery case 12, and the battery 10 has a battery module 16, which is made up of a plurality of stacked battery cells, arranged (fixed) on a lower case 22 and covered by an upper case 20. In this way, the battery 10 has the battery module 16 (battery pack 14) housed within the battery case 12.

[0038] In addition, in the battery 10, a support frame 40 is attached to the lower case 22 of the battery case 12, and the lower case 22 is attached to the vehicle body via the support frame 40, thereby supporting the battery case 12 on the vehicle body. In this way, the battery 10 is mounted on the vehicle.

[0039] Meanwhile, electrodeposition coating is widely used to form coating films on various vehicle components. For example, electrodeposition coating uses a cationic electrodeposition coating solution in which an epoxy resin or the like is used as the base material and a cationic resin is used as the coating material. In cationic electrodeposition coating, the upper case 20 or the lower case 22 to be coated is immersed in a cationic coating solution in which the cationic resin is positively charged. In electrodeposition coating, the upper case 20 or the lower case 22 serves as one electrode (cathode) of a pair of electrodes (anode and cathode), and an electrodeposition voltage according to preset electrodeposition conditions is applied between the upper case 20 or the lower case 22 and the other electrode (positive electrode) placed in the coating solution. As a result, the paint (paint components) in the coating solution is precipitated on the surfaces of the upper case 20 or the lower case 22, and the coating target is covered with a coating film (resin coating film) (a coating film is formed).

[0040] In such electrodeposition coating, by applying coating to the lower case 22 to which the assembly part 42 is attached, the assembly part 42 can be painted together with the lower case 22. In this case, since the flat surface 52 of the assembly part 42 is in surface contact with the lower case 22, uneven coating is likely to occur in the contact area 56 of the lower case 22, such as a thin coating film or exposed base material.

[0041] Here, a recess 58 is formed in the bottom plate 24 of the lower case 22 in a contact area 56 with which the flat surface 52 of the assembly part 42 comes into surface contact, and the recess 58 extends from the contact area 56 to a position corresponding to the cutout 54 of the frame part 42, which is a non-contact area. The non-contact area of ​​the lower case 22 is open and serves as an area to which the coating liquid adheres.

[0042] Therefore, in the bottom plate 24 of the lower case 22, the coating liquid can enter the recessed portion 58 opened by the cutout portion 54, and the coating liquid is supplied to the contact area 56. In other words, the recessed portion 58 extending from the contacted area into the contact area 56 forms a non-contact area within the contact area 56. Therefore, in the bottom plate 24 to which the frame part 42 is attached, the recessed portion 58 prevents the creation of an area separated from the non-contact area within the contact area 56.

[0043] As a result, the coating liquid can be supplied to the contact area 56 of the bottom plate 24 of the lower case 22 where the frame part 42 is in surface contact, and this coating liquid forms a coating film within the contact area 56. A coating film is also similarly formed on the surface of the flat part 52 of the frame part 42 that is in contact with the bottom plate 24, on the bottom plate 24 side.

[0044] In this way, even when the frame component 42 is attached in surface contact with the lower case 22, an appropriate coating film is formed, preventing the base material from being exposed. This reliably prevents rust from occurring and the progression of rust that has already occurred on the lower case 22 and the battery case 12 formed by the lower case 22.

[0045] On the other hand, when the vehicle body receives an impact in a vehicle emergency, the battery case 12 receives a load corresponding to the impact. In this case, the battery case 12 has a recess 58 that opens downward on the underside of the bottom plate 24 of the lower case 22, and a bead portion 60 is formed on the internal space side. This improves the rigidity of the bottom plate 24 of the lower case 22 in the battery case 12, and suppresses deformation when subjected to an external force.

[0046] Furthermore, the bead portions 60 are inclined in both the longitudinal direction and the width direction of the vehicle near the corners 44RF and 44LF of the lower case 24. Therefore, the use of the lower case 22 improves the rigidity of the battery case 12 against loads in both the longitudinal direction and the width direction of the vehicle. This prevents the battery case 12 from deforming even when subjected to loads from the front side of the vehicle or both sides in the width direction in the event of a vehicle emergency, thereby protecting the battery pack 14 housed inside.

[0047] In the battery case 12, recesses 58 are provided in the corners 44RF, 44LF of the lower case 22 to form bead portions 60, but the recesses 58 and bead portions 60 may also be formed in the corners 44RB, 44LB on the vehicle rear side of the lower case 22. This improves the rigidity of the battery case 12 against loads received from both sides in the vehicle width direction at the vehicle rear and vehicle rear portion, and enables the battery pack 14 to be protected against loads received from both sides in the vehicle width direction at the vehicle rear and vehicle rear.

[0048] In addition, in this embodiment, the recess 58 is formed in the contact area 56 of the lower case 22 with the frame part 42 so as to reach the notch 54 in the frame part 42. However, the recess may be formed so as to extend from the contact area 56 with the frame part 42 to a non-contact area that does not come into contact with the frame part 42.

[0049] FIG. 4 shows a plan view (rear view) of the main part of a lower case 22 according to a modified example, as viewed from below. In this modification, a circular hole 62 is provided in the support portion 46 of the frame component 42 on the vehicle rear side of the flat portion 52, and the circular hole 62 is formed to penetrate the support portion 46 in the vertical direction. As a result, the lower surface of the lower case 22 is opened downward by the circular hole 62.

[0050] For such a frame component 42, a recess 64 can be formed in the bottom plate 24 of the lower case 22, extending from within the contact region 56 to a position facing the circular hole 62 of the support portion 46. This allows the coating liquid that has entered the circular hole 62 of the support portion 46 to enter into the recess 64, and thereby penetrate from the recess 64 into the gap between the bottom plate 24 and the flat portion 52 in the contact region 56 of the bottom plate 24 of the lower case 22 and adhere thereto.

[0051] Therefore, even if recess 64 is formed in bottom plate 24 instead of recess 58, it is possible to prevent uneven painting such as a thin coating or exposure of the base material of bottom plate 24, as in the case where recess 58 is formed, and it is possible to suppress the occurrence and progression of rust in lower case 22.

[0052] In this embodiment and the modified example, the recesses 58, 64 are formed in the bottom plate 24 of the lower case 22. However, the recesses may be provided in attachment parts that are attached to the top plate 30 of the upper case 20 near the corners 44. In this case, it is preferable to form bead portions corresponding to the recesses. This prevents uneven paint on the top plate 30 of the upper case 20 and suppresses the occurrence and progression of rust. Furthermore, the bead portions formed together with the recesses improve the rigidity of the upper case 20, thereby improving the rigidity of the battery case 12.

[0053] Furthermore, the recesses are not limited to being formed at corners, but may also be formed near straight portions between corners. That is, recesses may be formed on attachment parts that are attached to the outer surface of peripheral wall 32 of upper case 20 or the outer surface of peripheral wall 26 of lower case 22. This prevents uneven paintwork on peripheral wall 32 of upper case 20 and peripheral wall 26 of lower case 22, and also improves the rigidity of each of peripheral walls 26, 32 by the bead portions formed corresponding to the recesses. [Explanation of symbols]

[0054] 10 Battery 12 Battery case (vehicle battery case, case body) 14 Battery pack 16 Battery module (multiple battery cells) 20 Upper case (case body) 22 Lower case (case body) 24 Bottom plate 40 Support Frame 42 Frame parts (mounting parts) 44 (44RF, 44LF) Corner (front end of vehicle) 46 Support part 52 Plane part 56 Contact area 58, 64 Recess 60 Bead section

Claims

1. a case body that houses a battery module having a plurality of stacked battery cells in its internal space; an attachment part that is attached in surface contact with the outer surface of the case body and is painted together with the case body; Including, A vehicle battery case including: a groove-shaped recess formed on the outer surface of the case body, extending from a contact area that makes surface contact when the mounting part is attached to a non-contact area of ​​the mounting part.

2. The case body includes a lower case on which the battery module is mounted; an upper case covering the lower case and defining an internal space between the upper case and the lower case in which the battery module is housed; The vehicle battery case according to claim 1 , wherein the recess is formed in the lower case.

3. The vehicle battery case according to claim 2 , wherein the recess is formed at a vehicle front end of the lower case.

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