Degassing mechanism for battery pack

Abstract

A degassing mechanism for a battery pack (20) comprises a floor panel (10) of a cabin of a vehicle (1), a battery pack (20) that is provided on an upper surface of the floor panel (10) and that stores a battery module, and a degassing tube (30) having one end side connected to the battery pack (20) and communicating with the inside of the battery pack (20) and the other end side exposed and opened to a lower surface side of the floor panel (10) from an opening (11) provided in the floor panel (10). The floor panel (10) is provided with a recess (12) that is recessed in an upper surface direction (+Z side) away from the road surface, and an opening (11) is provided in the recess (12).

Description

Degassing mechanism of battery pack

[0001] The present invention relates to a degassing mechanism for a battery pack provided in a vehicle.

[0002] In an electric vehicle, a battery pack may be disposed on the floor panel inside the vehicle cabin (for example, Patent Document 1). In such a vehicle, in order to prevent the harmful gas generated from the battery pack from filling the cabin when the gas is generated, a degassing mechanism for discharging the gas in the battery pack to the outside of the vehicle is provided. For example, in the degassing mechanism described in Patent Document 1, an exhaust pipe is connected to the battery pack. The exhaust pipe protrudes downward from the floor panel through an opening hole provided in the floor panel and opens on the lower side of the floor panel. Thereby, the gas in the battery pack can be discharged from the exhaust pipe to the outside of the vehicle.

[0003] Japanese Patent Application Laid-Open No. 2019-18679

[0004] However, in the degassing mechanism of Patent Document 1, the exhaust pipe protruding below the floor panel may come into contact with the road surface. If the exhaust pipe contacts the road surface and is damaged, blockage of the exhaust pipe may occur, and there is a possibility that the gas of the battery pack cannot be discharged properly.

[0005] An object of the present invention is to provide a degassing mechanism for a battery pack capable of suppressing damage caused by contact of an exhaust pipe with a road surface.

[0006] The degassing mechanism of the battery pack of the present invention includes a battery pack provided on the upper surface of the floor panel inside the vehicle cabin and a degassing tube connected to the battery pack. The degassing tube is exposed and opened on the lower surface side of the floor panel from an opening provided in the floor panel. And, the floor panel is provided with a concave portion that is concave in the upward direction away from the road surface, and the opening is provided in the concave portion.

[0007] Thereby, the opening end of the degassing tube is located in the concave portion, and the inconvenience that the degassing tube contacts the road surface and the damage of the degassing tube due to this can be suppressed.

[0008] A perspective view showing a part of the interior of a vehicle in one embodiment of the present disclosure. A perspective view of Figure 1 with the seats and floor sheet removed. A cross-sectional view of the degassing mechanism of the battery pack in this embodiment. A perspective view of the vicinity of the degassing tube connection position in the floor panel of this embodiment, viewed from the road side. A perspective view of Figure 4 with the cover and second cover removed. A perspective view of Figure 4 with the second cover removed. A cross-sectional view along the X direction near the degassing tube connection position in the floor panel. A cross-sectional view along the Y direction near the degassing tube connection position in the floor panel. A schematic plan view showing an example of deformation of the floor panel when an obstacle collides with the side of the vehicle in this embodiment. A schematic cross-sectional view showing the cross-sectional shape along line A-A in Figure 9.

[0009] An embodiment of the present disclosure will be described below. Figure 1 is a perspective view showing a part of the interior of a vehicle 1 having a degassing mechanism for a battery pack of this embodiment. Figure 2 is a perspective view in Figure 1 with the seats 2 and floor sheet 3 removed. Figure 3 is a cross-sectional view of the degassing mechanism of the battery pack 20. In the following description, the vehicle width direction of the vehicle 1 will be the X direction, and the front-rear direction will be the Y direction (+Y for the front side, -Y for the rear side). The direction perpendicular to the X and Y directions will be the Z direction, and the direction away from the road surface will be +Z.

[0010] As shown in Figure 1, the vehicle 1 is equipped with a floor panel 10 that constitutes the interior space, and a battery pack 20 (see Figure 2), a seat 2, and a floor sheet 3 are provided on the upper surface (+Z side) of the floor panel 10. The battery pack 20 is a high-voltage power supply that houses multiple battery modules inside, and its internal space is sealed. As shown in Figure 3, one end (pack-side end 31) of the degass tube 30 is connected to the battery pack 20. This allows the degass tube 30 to communicate with the internal space of the battery pack 20. The other end (open end 32: see Figure 3) of the degass tube 30 opens to the lower surface (-Z side) of the degass tube 30 through an opening 11 provided in the floor panel 10.

[0011] More specifically, the floor panel 10 has a recess 12 at the location where the opening 11 (see Figures 2 and 3) is provided. Figure 4 is a perspective view of the vicinity of the connection position of the degas tube 30 in the floor panel 10, viewed from the road surface side (-Z side). Figure 5 is a perspective view of Figure 4 with the cover 40 and the second cover 50 removed. Figure 6 is a perspective view of Figure 4 with the second cover 50 removed. Figure 7 is a cross-sectional view of the vicinity of the connection position of the degas tube 30 in the floor panel 10 along the X direction, and Figure 8 is a cross-sectional view of the vicinity of the connection position of the degas tube 30 in the floor panel 10 along the Y direction. As shown in Figures 5, 7, and 8, the recess 12 comprises a first recess 121 formed in a concave shape on the +Z side in the floor panel 10, and a second recess 122 that is further concave on the +Z side from the bottom of the first recess 121. The opening 11 is provided in the center of the second recess 122. As shown in Figure 5, the first recess 121 is formed with a length in the Y direction that is longer than its length in the X direction. The second recess 122 is located in the center of the first recess 121 in the Y direction, and the length of the second recess 122 in the Y direction is shorter than the length of the first recess 121 in the Y direction. The length of the second recess 122 in the X direction is approximately the same as the length of the first recess 121 in the X direction.

[0012] Furthermore, in this embodiment, as shown in Figures 6, 7, and 8, a cover 40 is provided on the -Z side of the recess 12, facing the recess 12. The cover 40 extends across the first recess 121 and the second recess 122, forming a closed space (first space S) between the first recess 121 and the second recess 122. Note that the closed space here is not a completely closed space, and gaps may be present in some areas.

[0013] The cover 40 comprises a first concave cover portion 41, a second convex cover portion 42, and a joining cover portion 43. As shown in Figures 5 and 8, the first concave cover portion 41 is configured to be concave along the surface of the first recess 121, and a pair of them are provided along the Y direction, sandwiching the second recess 122. Stud bolts 411 protruding toward the -Z side are erected on each of the first concave cover portions 41. In other words, when viewed from the Z direction, a pair of stud bolts 411 are provided along the X direction, sandwiching the opening 11. As will be described in detail later, the second cover 50 is fixed to the stud bolts 411.

[0014] The second convex cover portion 42 is formed convexly on the road surface side (-Z side) between a pair of first concave cover portions 41, and is continuous with the first concave cover portion 41. In other words, the second convex cover portion 42 is positioned opposite the second recess 122 of the floor panel 10, forming the first space S between the second recess 122 and the second convex cover portion 42. As shown in Figures 5 and 8, the protruding end face 421 on the -Z side of the second convex cover portion 42 is a substantially flat plane that is longitudinal in the X direction, and communication holes 422 that connect the first space S to the outside of the vehicle are provided on the ±X sides of the protruding end face 421, respectively. The communication holes 422 are provided, for example, in a projection view from the Z direction, at positions that sandwich the opening 11 in the Y direction.

[0015] The joining cover portion 43 is provided on the ±X sides of the first concave cover portion 41 and the second convex cover portion 42. The joining cover portion 43 is joined to the floor panel 10 on the ±X sides of the recess 12 (first recess 121, second recess 122) by welding. The entire joining cover portion 43 may be welded to the floor panel 10, or it may be partially welded at predetermined intervals in the Y direction. Furthermore, only the joining cover portion 43 may be joined to the floor panel 10, or the first concave cover portion 41 may also be joined to the first recess 121.

[0016] As shown in Figures 4, 7, and 8, the second cover 50 is provided on the -Z side of the cover 40 and covers the communication hole 422 of the cover 40. The second cover 50 comprises a substantially plate-shaped lid portion 51 that covers the second convex cover portion 42 and leg portions 52 extending from the lid portion 51. The lid portion 51 faces the second convex cover portion 42 of the cover 40 with a predetermined gap between them. In other words, in the area where the leg portions 52 are not provided at the outer peripheral edge of the lid portion 51, a gap M is interposed between the lid portion 51 and the cover 40, and the gas discharged from the communication hole 422 is released outside the vehicle through this gap M. In addition, by positioning the lid portion 51 facing the communication hole 422, the entry of foreign matter such as water and soil from the road surface into the communication hole is suppressed.

[0017] The legs 52 are connected to the ±Y sides at the outer peripheral ends of the cover portion 51 and extend toward the +Z side toward the first concave cover portion 41. The legs 52 opposite to the cover portion 51 form a mounting piece 521 parallel to the first concave cover portion 41, and the mounting piece 521 is provided with bolt insertion holes 522 corresponding to the positions of the stud bolts 411. The second cover 50 is fixed to the cover 40 by inserting the stud bolts 411 through the bolt insertion holes 522 provided in the mounting piece 521.

[0018] [Gas Discharge Mechanism] In the degassing structure of this embodiment as described above, when gas is generated from the battery module of the battery pack 20, the generated gas is discharged through the degassing tube 30 into the first space S on the -Z side of the floor panel 10. The gas discharged into the first space S is then released outside the vehicle through the gap M, passing between the cover 40 and the second cover 50 through the communication hole 422 of the cover 40.

[0019] Furthermore, in this embodiment, the second cover 50 covers the communication hole 422, thereby suppressing the entry of foreign matter into the communication hole 422. In addition, the recess 12 and the cover 40 form a closed space S, and the first space S is configured to communicate with the outside of the vehicle through the communication hole 422. For example, in the event of a fire, it is difficult for fire to enter through the first space S or the open end 32 of the degassing tube 30 exposed to the first space S.

[0020] [Deformation during collision] When the vehicle 1, as described above, collides with an obstacle, the impact of the collision may damage the battery pack 20. Therefore, it is necessary to mitigate the impact on the battery pack 20 during an impact. Figure 9 is a schematic plan view showing an example of deformation of the floor panel 10 when an obstacle D collides with the side of the vehicle 1, and Figure 10 is a schematic cross-sectional view showing the cross-sectional shape along line A-A in Figure 9. In this embodiment, as shown in Figures 3 and 10, the floor panel 10 has recesses 12 and open ends 32 of the degassing tubes 30 that constitute the degassing mechanism of this disclosure, positioned between the battery pack 20 placement position (battery position 14) and the panel end 15 connected to the side sill 4. The panel end 15 on the ±X side of the floor panel 10 (only the +X side is shown in the figure) is bent to the +Z side and fixed to the side sill 4. Between the panel end 15 and the recess 12, the lower surface 16 of the floor panel 10 is positioned on the -Z side of the recess 12. Therefore, from the panel end 15 on the side sill 4 side to the battery position 14, the floor panel 10 will have an uneven shape consisting of peaks (convex towards +Z), valleys (convex towards -Z), peaks, and valleys.

[0021] In such a floor panel 10, when an obstacle D collides with the vehicle 1 from the side (±X), the lower surface 16 of the floor panel 10 between the panel end 15 and the recess 12 deforms toward the -Z side, the inclined surfaces 123 on the ±X side of the recess 12 deform toward each other, and the recess 12 deforms toward the +Z side. In other words, the floor panel 10 absorbs the impact force by the lower surface 16 and the recess 12 collapsing in a bellows-like manner. In this case, as described above, in the recess 12, the length in the X direction of the first recess 121 is shorter than the length in the Y direction, so the shape of the recess 12 is more easily crushed by impacts from the X direction, improving the efficiency of impact force absorption. Also, the stud bolts 411 for fixing the second cover 50 are arranged along the Y direction on either side of the opening 11. If the stud bolts 411 were arranged on either side of the opening 11, the recess 12 would be less likely to collapse due to the stud bolts 411, and the efficiency of impact force absorption in the recess 12 would decrease. In contrast, in this embodiment, the inhibition of impact force absorption by the stud bolt 411 is suppressed, and the recess 12 becomes more easily crushed.

[0022] As described above, in this embodiment, when an impact force is applied from the X direction near the battery pack 20's position, the recess 12 collapses and the floor panel 10 deforms so as to fold in an accordion-like manner, thereby absorbing the impact force and suppressing the transmission of the impact force to the battery pack 20.

[0023] [Effects of this embodiment] The vehicle 1 of this embodiment has a degassing mechanism for the battery pack 20, which includes a floor panel 10, a battery pack 20 positioned on the upper surface (+Z side) of the floor panel 10, and a degassing tube 30 with one end connected to the battery pack 20 and the other end opening to the lower surface (-Z side) of the floor panel 10. In this degassing mechanism, the floor panel 10 is provided with a recess 12 that is concave on the +Z side, and the degassing tube 30 opens to the lower surface of the floor panel 10 through an opening 11 provided in the recess 12. In other words, the open end 32 of the degassing tube 30 is positioned in the recess 12 which is located on the +Z side (away from the road surface) rather than the lowest surface (the area closest to the road surface) of the floor panel 10. Therefore, the possibility of the degassing tube 30 coming into contact with the road surface while the vehicle 1 is in motion can be reduced, and damage to the degassing tube 30 due to contact with the road surface can be suppressed. Furthermore, if an obstacle collides with the side of the vehicle 1, the shape of the recess 12 collapses, absorbing the impact force and suppressing the transmission of the impact force to the battery pack 20.

[0024] In this embodiment, the length of the recess 12 (first recess 121) in the vehicle width direction (X direction) is shorter than the length in the front-rear direction (Y direction). The battery pack 20 is generally positioned closer to the side of the vehicle 1 than to the front or rear end. Therefore, it is preferable to provide a configuration that protects the battery pack 20 in the event that an obstacle collides with the side of the vehicle 1. In this embodiment, since the length of the first recess 121 in the X direction is shorter than the length in the Y direction, the opposing inclined surfaces 123 are more likely to collapse in the direction of proximity due to impact from the X direction, and this deformation allows the recess 12 to effectively absorb the impact force transmitted from the X direction. Therefore, the propagation of impact force to the battery pack 20 can be suppressed, and damage to the battery pack 20 due to collision can be suppressed.

[0025] In this embodiment, the recess 12 has a first recess 121 that is concave on the +Z side, and a second recess 122 that is further concave on the +Z side from the bottom of the first recess. The opening 11 is provided in the second recess 122. This allows the open end 32 of the degass tube 30 to be positioned further away from the road surface, thereby further suppressing contact between the open end 32 and the road surface. In addition, by providing the second recess 122, the protruding dimension of the open end 32 of the degass tube 30 can be secured, and the open end 32 of the degass tube 30 can be housed within the recess 12.

[0026] The degassing mechanism in the vehicle 1 of this embodiment further includes a cover 40 positioned on the -Z side of the recess 12, facing the region where at least the opening 11 of the recess 12 is provided (i.e., the second recess 122). The provision of the cover 40 further suppresses contact between the open end 32 of the degassing tube 30 and the road surface. The cover 40 also suppresses the inconvenience of foreign matter entering the degassing tube 30 from the open end 32.

[0027] In this embodiment, the cover 40 forms a substantially closed first space S between itself and the recess 12, and the cover 40 is provided with a communication hole 422 that connects the first space S to the outside of the vehicle. This allows the gas discharged from the degassing tube 30 into the first space S to be discharged to the outside of the vehicle through the communication hole 422. Furthermore, if the cover 40 is not provided, there is a risk that fire may enter the battery pack 20 through the open end 32 of the degassing tube 30 in the event of a fire. In contrast, in this embodiment, it is difficult for fire to enter the open end 32 of the degassing tube 30, and overheating of the battery pack 20 can be suppressed.

[0028] In this embodiment, the cover 40 is joined to the floor panel 10 by welding. This allows the cover 40 to be joined without creating holes in the floor panel 10. In other words, when the cover 40 is fixed to the floor panel 10 with bolts or screws, an opening is required in the floor panel 10 for inserting the bolts or screws, which can lead to problems such as reduced durability and reduced airtightness of the floor panel 10. In contrast, in this embodiment, the cover 40 can be fixed without reducing the durability or airtightness of the floor panel 10.

[0029] The degassing mechanism in the vehicle 1 of this embodiment further includes a second cover 50 positioned on the -Z side of the cover 40 and covering the communication hole 422. If the second cover 50 is not provided, the communication hole 422 faces the road surface, making it easy for foreign matter such as water and soil splashed up while the vehicle 1 is running to enter. In contrast, in this embodiment, the entry of foreign matter from the communication hole 422 of the cover 40 into the first space S and the degassing tube 30 positioned within the first space S can be further suppressed.

[0030] In this embodiment, the second cover 50 is fixed to the cover 40 by stud bolts 411 erected on the cover 40. This eliminates the need to provide openings in the cover 40 or the floor panel 10, thereby suppressing a decrease in the durability of the floor panel 10 and the cover 40.

[0031] In this embodiment, a pair of stud bolts 411 are provided in the Y direction, flanking the opening 11. If the stud bolts 411 are provided along the X direction of the recess 12, when an obstacle collides with the vehicle 1 from the side, the deformation of the recess 12 may be hindered by the stud bolts 411, and as a result, the impact force may be transmitted to the battery pack 20 along the X direction. In contrast, by providing the stud bolts 411 along the Y direction, the deformation of the recess 12 is not hindered, the impact force along the X direction can be absorbed, and damage to the battery pack 20 can be suppressed.

[0032] [Modifications] The present invention is not limited to the embodiments described above, but also includes the following modifications to the extent that the objectives of the present invention can be achieved.

[0033] [Modification 1] In the above embodiment, in order to mitigate the impact force when the vehicle 1 collides from the side, the length of the recess 12 in the X direction is made shorter than the length in the Y direction, and the stud bolts 411 are arranged along the Y direction of the recess 12. In contrast, depending on the placement position of the battery pack 20, or depending on the direction in which the impact force is to be mitigated, for example, the length of the recess 12 in the X direction may be made longer than the length in the Y direction, and the installation position of the stud bolts 411 may be changed.

[0034] [Modification 2] In the above embodiment, a configuration comprising a first recess 121 and a second recess 122 was illustrated, but this configuration is not essential. For example, the recess 12 may consist only of the first recess 121. In this case, by increasing the depth of the first recess 121, sufficient space can be secured for the placement of the open end 32 of the degass tube 30.

[0035] [Modification 3] In the above embodiment, an example configuration is shown in which a cover 40 and a second cover 50 are provided to cover the recess 12, but the invention is not limited thereto. By configuring the degas tube 30 so that its open end 32 is housed within the recess 12, contact between the road surface and the open end 32 of the degas tube 30 can be suppressed.

[0036] 1...vehicle, 10...floor panel, 11...opening, 12...recess, 20...battery pack, 30...degass tube, 31...pack side end, 32...opening end, 40...cover, 41...first concave cover part, 42...second convex cover part, 43...joint cover part, 50...second cover, 51...lid part, 52...leg part, 121...first recess, 122...second recess, 123...inclined surface, 411...stud bolt, 421...protruding end face, 422...communication hole, 521...mounting piece, 522...bolt insertion hole.

Claims

1. A degassing mechanism for a battery pack comprising: a floor panel constituting the passenger compartment of a vehicle; a battery pack provided on the upper surface of the floor panel and housing a battery module; and a degassing tube having one end connected to the battery pack and communicating with the inside of the battery pack, and the other end opening out to the lower surface of the floor panel through an opening provided in the floor panel, wherein the floor panel has a recess that is concave in the direction away from the road surface, and the opening is provided in the recess.

2. The degassing mechanism for a battery pack according to claim 1, wherein the length of the recess in the vehicle width direction is shorter than the length of the recess in the longitudinal direction perpendicular to the vehicle width direction.

3. The degassing mechanism for a battery pack according to claim 1, wherein the recess has a first recess that is concave in the direction of the upper surface and a second recess that is concave in the direction of the upper surface from the bottom of the first recess, and the opening is provided in the second recess.

4. The degassing mechanism for a battery pack according to claim 1, further comprising a cover disposed on the road surface side of the recess, facing at least the region of the recess where the opening is provided.

5. The degassing mechanism for a battery pack according to claim 4, wherein the cover forms a substantially closed first space between itself and the recess, and is provided with a communication hole that connects the first space to the outside of the vehicle.

6. The degassing mechanism for a battery pack according to claim 4, wherein the cover is joined to the floor panel by welding.

7. The degassing mechanism for a battery pack according to claim 5, comprising a second cover positioned on the road surface side of the cover and covering the communication hole.

8. The degassing mechanism for a battery pack according to claim 7, wherein the second cover is fixed to the cover by stud bolts erected on the cover.

9. The degassing mechanism for a battery pack according to claim 8, wherein a pair of stud bolts are provided on either side of the opening, along the front-rear direction perpendicular to the vehicle width direction of the vehicle.

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