Battery pack

Abstract

A battery pack for a hybrid vehicle having an engine, the battery pack comprising: a case for accommodating at least one battery cell; a metal cylindrical member fixed to the case so as to penetrate the case; an exhaust pipe part constituting a part of an exhaust pipe through which exhaust gas from the engine flows, and inserted into the cylindrical member so as not to come into contact with an inner peripheral surface of the cylindrical member; and two sealing members provided so as to close one end and the other end of the cylindrical member, and in which a first through hole into which the exhaust pipe part is inserted and at least one second through hole different from the first through hole are formed.

Description

Battery pack

[0001] The present disclosure relates to a battery pack.

[0002] Hybrid vehicles with an engine and a battery pack face layout issues with the engine's exhaust pipe and battery pack. For example, attempting to arrange the exhaust pipe so that it passes to the left or right side of the battery pack in the vehicle's width direction would increase the length of the exhaust pipe or increase the number of bends, resulting in increased exhaust gas pressure loss and adversely affecting exhaust gas flow. On the other hand, shortening the length of the exhaust pipe or reducing the number of bends would result in the battery pack being positioned to the right or left of the vehicle's width center, resulting in poor vehicle balance. As an alternative layout, Patent Document 1 discloses a configuration in which a recessed groove is formed in the battery pack case. By arranging the exhaust pipe straight along this groove, the bends in the exhaust pipe are eliminated and the battery pack can be positioned in the vehicle's width center.

[0003] JP 2019-25934 A

[0004] However, in the battery pack disclosed in Patent Document 1, the portion where the groove is provided is weaker than other portions, and there is a risk that the battery pack will be more susceptible to damage starting from this groove in the event of a vehicle collision.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a battery pack that can be laid out in an appropriate position relative to the exhaust pipe, without reducing the strength of the battery pack and while suppressing the thermal effect of exhaust gas on the battery cells.

[0006] In order to achieve the above-mentioned object, the battery pack of the present disclosure is a battery pack for a hybrid vehicle having an engine, and comprises: a case that houses at least one battery cell; a metallic tubular member fixed to the case so as to penetrate the case; an exhaust pipe section that forms part of an exhaust pipe through which exhaust gas from the engine flows, the exhaust pipe section being inserted into the tubular member so as not to contact the inner surface of the tubular member; and two sealing members that are provided to block one end and the other end of the tubular member, the two sealing members having a first through hole through which the exhaust pipe section is inserted and at least one second through hole different from the first through hole.

[0007] According to the battery pack of the present disclosure, the exhaust pipe inserted into the tubular member fixed to the case so as to penetrate the case constitutes part of the exhaust pipe through which exhaust gas from the engine flows, allowing the battery pack to be laid out without bending the exhaust pipe. The tubular member also improves the strength of the case. Furthermore, when a vehicle equipped with the battery pack is running, air flows between the inner circumferential surface of the tubular member and the exhaust pipe through the second through-hole, allowing heat exchange between the exhaust gas flowing through the exhaust pipe and the air, thereby cooling the exhaust gas. This reduces the impact of exhaust gas heat on the tubular member and, ultimately, on the battery cells inside the case. This allows the battery pack to be laid out in an appropriate position relative to the exhaust pipe without reducing the strength of the battery pack and while reducing the impact of exhaust gas heat on the battery cells.

[0008] Fig. 1 is a schematic diagram of a battery pack according to an embodiment of the present disclosure, showing the interior of the case with the case lid removed from the case tray; Fig. 2 is a diagram showing the arrangement of a battery module and a cylindrical member inside the case of the battery pack according to an embodiment of the present disclosure; Fig. 3 is a cross-sectional view showing the internal configuration of a cylindrical member of a battery pack according to another embodiment of the present disclosure; Fig. 4 is a diagram showing an example of the configuration of a vibration suppression member provided at a connection portion between an exhaust pipe and an exhaust pipe section in a battery pack according to yet another embodiment of the present disclosure.

[0009] Hereinafter, a battery pack according to an embodiment of the present disclosure will be described with reference to the drawings. The embodiment described below shows one aspect of the present disclosure, and is not intended to limit the present disclosure. Any modification can be made within the scope of the technical concept of the present disclosure.

[0010] 1 shows a battery pack 1 mounted on a vehicle. The vehicle is a hybrid electric vehicle (HV) powered by an engine and a motor. The hybrid electric vehicle is, for example, a plug-in hybrid electric vehicle (PHEV, PHV) that can be charged from an external power source or can externally supply power to an external device, but is not limited to a plug-in hybrid electric vehicle.

[0011] The battery pack 1 includes a case 2 and a battery module 5 housed within the case 2. The case 2 includes a tray 3 on which the battery module 5 is placed, and a lid 4 that combines with the tray 3 on which the battery module 5 is placed to seal the battery module 5 inside the case 2. While FIG. 1 illustrates a configuration in which the battery module 5 includes two battery modules 5a and 5b, the configuration is not limited to this, and it is sufficient that at least one battery module is housed within the case 2. Furthermore, what is housed within the case 2 is not limited to a battery module composed of multiple battery cells, and at least one battery cell may be housed within the case 2.

[0012] A metallic cylindrical member 10 is provided in the case 2 so as to penetrate the case 2. Although not limited thereto, the cylindrical member 10 may be an extruded aluminum material. In order to provide the cylindrical member 10 in the case 2 so as to penetrate the case 2, notches 3 b and 4 b into which the cylindrical member 10 fits are formed in a pair of side plates 3 a, 3 a of the tray 3, which are positioned in the longitudinal direction of the vehicle when the battery pack 1 is mounted on the vehicle, and a pair of side plates 4 a, 4 a of the lid 4, which are positioned in the longitudinal direction of the vehicle. In other words, the cylindrical member 10 "penetrating the case 2" means that the cylindrical member 10 penetrates one of the pair of side plates 3 a, 3 a from the outside of the case 2, extends inside the case 2, and further penetrates the other of the pair of side plates 3 a, 3 a to extend to the outside of the case 2. When the battery pack 1 is mounted on the vehicle, a cross member 3d extending in the vehicle width direction may be provided on the tray 3. If such a cross member 3d is provided, the cross member 3d also has a notch 3e formed therein into which the tubular member 10 fits. While Fig. 1 shows a configuration in which one cross member 3d is provided, two or more cross members 3d may be provided between a pair of side plates 3a, 3a. In that case, a notch 3e is formed in each of the cross members 3d.

[0013] An exhaust pipe section 11 is inserted into the cylindrical member 10 so as not to come into contact with an inner peripheral surface 10a (see FIG. 3) of the cylindrical member 10. The exhaust pipe section 11 is connected to an exhaust pipe P through which exhaust gas G discharged from an engine (not shown) flows, and constitutes a part of the exhaust pipe P. In other words, exhaust gas G flows through the exhaust pipe section 11. Connection sections 11a for connecting to the exhaust pipe P are provided at both ends of the exhaust pipe section 11. The connection sections 11a at both ends of the exhaust pipe section 11 are located outside the cylindrical member 10. The exhaust pipe P is divided into an upstream section P1 and a downstream section P2 with respect to the flow direction of the exhaust gas G so that the exhaust pipe section 11 can be connected midway through the exhaust pipe P. Connection sections Pa for connecting to the connection sections 11a at both ends of the exhaust pipe section 11 are provided at the downstream end of section P1 and the upstream end of section P2, respectively.

[0014] Two sealing members 12, 13 are fitted into both ends of the cylindrical member 10 so as to close the openings at both ends of the cylindrical member 10. The sealing member 12 has a first through hole 15 into which the exhaust pipe section 11 is inserted, and at least one second through hole 16 different from the first through hole 15. Although not shown in FIG. 1 , the sealing member 13 has the same configuration as the sealing member 12. If a cross member 3d is provided on the tray 3, a sealing member 14 having the same configuration as the sealing member 12 may be provided inside the cylindrical member 10 at the position of the notch 3e of the cross member 3d.

[0015] In the battery pack 1 having the above-described configuration, the exhaust pipe section 11 inserted into the tubular member 10 fixed to the case 2 so as to penetrate through the case 2 constitutes part of the exhaust pipe P through which exhaust gas G from the engine flows, allowing the battery pack 1 to be laid out without bending the exhaust pipe P. Furthermore, the tubular member 10 improves the strength of the case 2. Furthermore, when the vehicle equipped with the battery pack 1 is running, air flows between the inner circumferential surface of the tubular member 10 and the exhaust pipe section 11 through the second through-holes 16, resulting in heat exchange between the exhaust gas G flowing through the exhaust pipe section 11 and the air, thereby cooling the exhaust gas G. This reduces the impact of the heat of the exhaust gas G on the tubular member 10 and, ultimately, the battery module 5 inside the case 2. This allows the battery pack 1 to be laid out in an appropriate position relative to the exhaust pipe P without reducing the strength of the battery pack 1 and while reducing the impact of the heat of the exhaust gas G on the battery module 5.

[0016] In the battery pack 1 shown in FIG. 1 , the cross section of the tubular member 10 cut perpendicularly to the length of the tubular member 10 has a hexagonal shape, but this is not limited to this shape. The cross section may be a polygon other than a hexagon, or may be a circle, an ellipse, or any other shape. The shapes of the sealing members 12, 13, and 14 are also the same as the cross section of the tubular member 10. The cross section of the tubular member 10 is preferably hexagonal for the reasons explained below. When the battery modules 5 are to be accommodated as tightly as possible within the case 2, the battery modules 5 and the tubular member 10 come into contact with each other. As shown in FIG. 2 , when the cross section of the tubular member 10 has a hexagonal shape, even when the battery modules 5 and the tubular member 10 are arranged so as to come into contact with each other, gaps 17 and 18 are formed between the outer surfaces 5 c of the battery modules 5 and the outer surfaces 10 b of the tubular member 10. Cables connected to the battery modules 5 can be passed through these gaps 17 and 18, thereby achieving the advantageous effect of making the battery pack 1 more compact.

[0017] When the cross-sectional shape of the cylindrical member 10 and the sealing members 12, 13, and 14 are each hexagonal, it is preferable that the second through holes 16 of each of the sealing members 12, 13, and 14 have a configuration in which the second through holes 16 form a honeycomb structure. In order to improve the heat exchange efficiency between the air flowing between the inner circumferential surface 10a of the cylindrical member 10 and the exhaust pipe portion 11 and the exhaust gas G flowing through the exhaust pipe portion 11, it is preferable to increase the aperture ratio of the second through holes 16 so that more air flows into the cylindrical member 10. However, doing so reduces the strength of the sealing members 12, 13, and 14, which may reduce the effect of improving the strength of the case 2. In contrast, if the second through holes 16 form a honeycomb structure, it is possible to increase the aperture ratio of the second through holes 16 while minimizing the reduction in the strength of the sealing members 12, 13, and 14.

[0018] 3 , in a battery pack 1 according to another embodiment, a heat insulating material 20 may be provided between the inner circumferential surface 10a of the tubular member 10 and the outer circumferential surface 11b of the exhaust pipe portion 11. The heat insulating material 20 may be a heat insulating material 20a that covers the outer circumferential surface 11b of the exhaust pipe portion 11, or a heat insulating material 20b that is laid between the inner circumferential surface 10a of the tubular member 10 and the outer circumferential surface 11b of the exhaust pipe portion 11, or a combination thereof. This further enhances the effect of suppressing the influence of the heat of the exhaust gas G on the battery module 5.

[0019] As shown in FIG. 4 , in a battery pack 1 according to yet another embodiment, the exhaust pipe P and the exhaust pipe section 11 may be connected via a vibration damping member 30. The vibration damping member 30 has the function of absorbing vibrations even when the exhaust pipe P vibrates, thereby damping the vibrations transmitted to the exhaust pipe section 11. As such a vibration damping member 30, for example, one including connecting pipes 31 and 32 inserted into the connecting portion Pa of the exhaust pipe P and the connecting portion 11a of the exhaust pipe section 11, respectively, and a flexible pipe 33 connecting the connecting pipes 31 and 32 can be used. When the exhaust pipe P and the exhaust pipe section 11 are connected via such a vibration damping member 30, even if the exhaust pipe P vibrates, the flexible pipe 33 displaces in accordance with the vibration of the exhaust pipe P, thereby damping the vibrations, thereby reducing the vibrations transmitted to the exhaust pipe section 11. Figure 4 shows a configuration in which the upstream portion P1 of the exhaust pipe P is connected to the exhaust pipe section 11 via the vibration damping member 30, but the downstream portion P2 (see Figure 1) of the exhaust pipe P may also be connected to the exhaust pipe section 11 via the vibration damping member 30, or only one of the portions may be connected via the vibration damping member 30.

[0020] REFERENCE SIGNS LIST 1 Battery pack 2 Case 5 Battery module (battery cell) 5a Battery module (battery cell) 5b Battery module (battery cell) 10 Cylindrical member 10a Inner peripheral surface (of cylindrical member) 11 Exhaust pipe portion 12 Sealing member 13 Sealing member 15 First through-hole 16 Second through-hole 20 Heat insulating material 30 Vibration suppressing member G Exhaust gas P Exhaust pipe

Claims

1. A battery pack for a hybrid vehicle having an engine, comprising: a case that houses at least one battery cell; a metallic tubular member that is fixed to the case so as to penetrate the case; an exhaust pipe section that forms part of an exhaust pipe through which exhaust gas from the engine flows, the exhaust pipe section being inserted into the tubular member so as not to contact the inner surface of the tubular member; and two sealing members that are provided to close one end and the other end of the tubular member, the two sealing members having a first through hole through which the exhaust pipe section is inserted and at least one second through hole different from the first through hole.

2. The battery pack according to claim 1, further comprising a heat insulating material provided between the inner peripheral surface of the cylindrical member and the outer peripheral surface of the exhaust pipe portion.

3. The battery pack according to claim 1 or 2, wherein the cross section of said cylindrical member cut perpendicularly to the longitudinal direction of said cylindrical member has a polygonal shape.

4. The battery pack according to claim 3, wherein the polygon is a hexagon.

5. The battery pack according to claim 4, wherein the second through holes form a honeycomb structure.

6. The battery pack according to claim 1 or 2, further comprising a vibration damping member provided on at least one of both ends of the exhaust pipe portion.

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