JP2020061285A - Battery pack - Google Patents

Abstract

To provide a battery pack capable of ensuring battery cooling performance while compacting a battery pack cooling structure.SOLUTION: A battery pack 1 that houses a battery module 7 and is installed in a vehicle includes a sheet metal case 9 that houses the battery module, a heat transfer sheet 15 having thermal conductivity provided between an inner bottom surface 13a of the sheet metal case and the lower surface of the battery module, and a radiating fins 3 protruding from the outer bottom surface 13b of the sheet metal case, and the radiating fin is provided by being exposed to the outside of the vehicle.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a battery pack, and more particularly, to a battery pack mounted on a vehicle and having a battery module.

  Cooling of a battery pack having a battery module mounted on a vehicle needs to be performed efficiently depending on how the battery is used. For example, in the case of an electric vehicle (EV), the amount of heat generated by the battery is large because the vehicle travels only with the output of the running battery. Therefore, a structure is known in which forced battery cooling is performed using a blower or the like. However, the arrangement of air passages is required, which complicates the structure of the battery pack and increases its size.

  On the other hand, a battery for the purpose of driving assistance, recovery of regenerative energy, etc., has a smaller size and a lower capacity than a battery for running an electric vehicle, and therefore generates less heat and does not require cooling as much as the battery for running. In the case of cooling a battery that generates less heat than the running battery, the cooling structure of the battery pack can be made compact, but it is difficult to secure battery cooling performance while achieving compactness. .

  There is known a technique for effectively using the running wind of a vehicle in order to provide a battery cooling performance while achieving a compact battery pack cooling structure.

  For example, Patent Document 1 discloses a battery pack. The battery pack includes a module battery, and the module battery has an outer surface covered with a resin material. A part of the resin material is formed of a resin material having a high thermal conductivity, and the resin material having a high thermal conductivity is insert-molded with heat radiation fins for exchanging heat between the outside and the inside. ing.

  Further, Patent Document 2 discloses a battery module in which a plurality of closely packed batteries are housed inside a metal case. This metal case is installed on the cooling surface of the cooling passage of the heat exchanger through which traveling wind flows. Further, the heat conductive elastic body 50 is arranged between the cooling surface and the metal case in FIG. 5 (b), and the cooling fin is formed in the cooling passage in FIG. 5 (c). Shows a configuration in which cooling fins are integrally formed on a metal case.

JP 2012-243446 A Japanese Patent Laid-Open No. 2018-60594

  Patent Documents 1 and 2 show that cooling fins are provided to cool by using traveling wind. However, in Patent Document 1, the battery pack is placed on an under tray assembled to the lower surface of the vehicle body. The structure is assembled and assembled (FIG. 3), and in Patent Document 2, the structure is such that a passage through which traveling wind flows is provided inside the vehicle (FIG. 1). For this reason, the traveling wind does not hit the cooling fins efficiently, and it is difficult to obtain effective cooling by the traveling wind.

  Further, in Patent Documents 1 and 2, a heat transfer sheet is sandwiched between the inside of the bottom surface of a case formed to cover a plurality of battery modules and the bottom surface of the battery module, and It does not show a configuration in which heat is efficiently transmitted and heat is dissipated by a cooling fin formed on the bottom surface of the case. FIG. 5B of Patent Document 2 shows a heat conductive elastic body 50. The heat conductive elastic body 50 is arranged between the cooling surface of the cooling passage of the heat exchanger and the metal case. However, it is not arranged between the bottom surface of the battery and the inside of the bottom surface of the metal case.

  Therefore, in view of the above problems, at least one embodiment of the present invention has an object to provide a battery pack capable of ensuring battery cooling performance while compacting the battery pack cooling structure.

  (1) The present invention has been made to achieve the above-mentioned object, and at least one embodiment of the present invention is a battery pack that houses a battery module and is mounted in a vehicle, and houses the battery module. A sheet metal case, a heat transfer sheet having thermal conductivity sandwiched between an inner bottom surface of the sheet metal case and a lower surface of the battery module, and a heat radiation fin projecting on an outer bottom surface of the sheet metal case, The heat radiation fin is provided so as to be exposed to the outside of the vehicle.

  According to such a configuration, the heat generated from the battery module is transferred to the bottom surface of the sheet metal case by the heat transfer sheet having thermal conductivity sandwiched between the inner bottom surface of the sheet metal case and the lower surface of the battery module. To be done. The heat transferred to the bottom surface of the sheet metal case is cooled by the radiating fins using traveling wind.

  In this way, the heat from the battery module can be efficiently transferred to the heat radiation fins by the heat transfer sheet, the sheet metal case, and the heat radiation fins. Further, since the radiation fin is provided exposed to the outside of the vehicle, the traveling wind can be directly contacted with the radiation fin without being blocked, and efficient cooling can be performed. Further, since the traveling wind directly hits the heat radiation fins to cool it, a ventilation duct or the like for guiding the cooling air or the like to the heat radiation fins is not necessary, so that the cooling structure of the battery pack can be made compact. That is, the battery cooling performance can be ensured while making the cooling structure of the battery pack compact.

  (2) In some embodiments, a surface of the heat dissipation fin is coated with a light shielding coating.

  According to this structure, since the surface of the heat radiation fin is provided with the light-shielding coating, the heat radiation fin provided outside the vehicle is heated by the radiation heat from the road surface and the cooling effect is reduced. It can be prevented.

  (3) In some embodiments, the radiating fins are integrally formed on the bottom surface of the sheet metal case.

  According to this structure, the heat dissipation fins can be easily formed, and the heat transferred to the bottom surface of the sheet metal case is efficiently transferred to the heat dissipation fins.

  (4) In some embodiments, the heat radiation fin is provided over the entire bottom surface of the sheet metal case and has a plurality of convex portions extending in the front-rear direction of the vehicle.

  According to such a configuration, since the radiation fins are provided over the entire bottom surface of the sheet metal case, the heat transferred to the bottom surface of the sheet metal case can be efficiently cooled by the radiation fins.

  (5) In some embodiments, the battery module is a power source to a motor generator that assists driving of a running engine of the vehicle.

  With such a configuration, the battery module is a power source for the motor generator that assists the driving of the vehicle running engine, and therefore generates less heat and has a lower cooling capacity than the running battery of the electric vehicle. Since the number of batteries required is smaller than that of batteries, the cost of cooling parts can be reduced, and sufficient air cooling performance can be secured by using traveling wind.

  (6) In some embodiments, only the radiating fins project below the floor of the vehicle.

  According to such a configuration, only the heat radiation fin is exposed under the floor of the vehicle, so that the distance between the lower end of the heat radiation fin and the road surface can be secured. As a result, damage to the radiation fin due to contact with an obstacle or the like can be suppressed as much as possible, and heat radiation performance can be ensured. Further, it is possible to reduce the possibility that the traveling property of the vehicle is hindered by the contact of the radiation fins with an obstacle or the like.

  According to at least one embodiment of the present invention, the battery cooling performance can be ensured while making the cooling structure of the battery pack compact.

It is a perspective view showing the whole battery pack composition concerning one embodiment of the present invention. It is an expansion perspective view of the part of the radiation fin in FIG. FIG. 2 is a side view showing how the battery pack of FIG. 1 is mounted on a vehicle. 1 illustrates a battery pack according to an embodiment of the present invention, and is a configuration block diagram of a travel assistance system of a vehicle in which the battery pack is mounted. FIG. 3 is a cross-sectional view showing a battery pack according to an embodiment of the present invention, showing a state in which a light-shielding coating is applied to heat dissipation fins. FIG. 6 is a side view showing a battery pack according to an embodiment of the present invention, showing another example of mounting the battery pack on a vehicle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the relative arrangement and the like of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention to these, but are merely illustrative examples. In the description of the embodiments, the front-rear, left-right, and up-down directions are defined as the directions viewed from an occupant seated facing the front of the vehicle when the battery pack is assembled in the vehicle.

  A battery pack according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the overall configuration of the battery pack 1, FIG. 2 shows an enlarged view of the heat dissipating fins 3 of the battery pack 1, and FIG. 3 shows how the battery pack 1 is mounted on a vehicle 5.

  As shown in FIG. 1, the battery pack 1 is configured by accommodating a battery module 7 inside a case (metal case) 9 formed of a box-shaped metal material, and is mounted on a vehicle 5 as described later. Has been done.

  The case 9 is made of a metal material having heat resistance and impact resistance, and is preferably made of, for example, an aluminum alloy.

  The battery module 7 is formed by arranging a plurality of battery cells 11 by a holder (not shown), held inside the case 9, and electrically connected by a bus bar (not shown). In FIG. 1, only one battery module 7 is shown in the battery pack 1, but a plurality of battery modules 7 may be provided depending on the power capacity of the battery module 7.

  A heat transfer sheet 15 having thermal conductivity is provided between the inner bottom surface 13 a of the bottom surface 13 of the case 9 and the lower surface 7 a of the battery module 7. The heat transfer sheet 15 is preferably made of a silicon material having excellent high thermal conductivity, flexibility and heat resistance. The heat transfer sheet 15 is provided at least over the entire lower surface 7a of the battery module 7.

  The heat radiation fins 3 are provided on the outer bottom surface 13b of the case 9, and the heat radiation fins 3 have a plurality of convex portions 14 extending parallel to the front-rear direction of the vehicle 5. As shown in FIG. 2, on the outer bottom surface 13b of the case 9, the radiating fins 3 are formed in an uneven shape over the entire outer bottom surface 13b, that is, over the entire length in the longitudinal direction of the box shape. It extends in parallel over the entire length in the lateral direction. In addition, the interval between the adjacent convex portions 14 is formed such that traveling wind passes through between the adjacent convex parts 14 and the heat radiation effect of the heat radiation fins 3 is favorably performed.

  Further, the radiation fin 3 is integrally formed on the outer bottom surface 13b of the case 9 with the same material as the case. Alternatively, each of the convex portions 14 of the heat dissipation fin 3 or an assembly of a plurality of convex portions 14 may be joined to the outer bottom surface 13b of the case 9 by welding or the like.

  In the case of integral formation, the heat dissipation fins 3 are easily formed, and the heat transferred to the bottom surface 13 of the case 9 is efficiently transferred to the heat dissipation fins 3. In the case of separate formation, in order to improve the heat dissipation performance of the heat dissipation fin 3, only the part of the heat dissipation fin 3 can be formed of a material having a thermal conductivity different from that of the case 9.

  Further, the portion of the radiation fin 3 is exposed and installed outside the vehicle 5. That is, a member that covers the periphery of the radiating fin 3 is not provided, and the running wind directly hits the radiating fin 3.

  As shown in FIG. 3, the battery pack 1 is provided at a position below the passenger seat 17 of the vehicle 5. Further, the case 9 is arranged so that its longitudinal direction is located in the vehicle width direction and its lateral direction is located in the vehicle front-rear direction.

  Further, the battery pack 1 is located below the passenger seat 17 of the vehicle 5, and even if the entire case 9 of the battery pack 1 is arranged on the outdoor side, a part of the case 9 is on the outdoor side and the rest is on the outdoor side. It may be placed inside.

  In the case where the entire case 9 is arranged on the outdoor side, the floor surface below the passenger seat 17 is formed to be recessed toward the interior side, and the upper portion of the case 9 is located in the recessed portion, and the bottom surface of the vehicle body is below the floor surface. The battery pack 1 is attached to the. As shown in FIG. 3, at least a portion of the radiation fin 3 is installed so as to be exposed below the floor surface of the vehicle 5 in a vehicle side view.

  When part of the case 9 is placed outside and the rest is placed inside, an opening is formed in the floor below the passenger seat 17, and the upper portion of the case 9 is located inside the room through the opening. However, a seal member that blocks communication with the outside of the room is provided and attached around the opening. As shown in FIG. 3, at least a portion of the radiation fin 3 is installed so as to be exposed below the floor surface of the vehicle 5 in a vehicle side view.

  According to the embodiment configured as described above, the heat generated from the battery module 7 is transferred to the inside bottom surface 13a of the case 9 and the bottom surface 7a of the battery module 7 and has thermal conductivity. The heat sheet 15 transfers the heat to the bottom surface 13 of the case 9. Then, the heat transferred to the bottom surface 13 of the case 9 is cooled by the radiating fins 3 by using traveling wind.

  Thus, the heat from the battery module 7 can be efficiently transferred to the heat radiation fins 3 by the metal case 9, the heat transfer sheet 15, and the heat radiation fins 3. Further, since the heat radiation fins 3 are provided so as to be exposed to the outside of the vehicle 5, the traveling wind can be directly contacted with the heat radiation fins 3 without being blocked, and efficient cooling can be performed. In addition, since the traveling wind directly hits the heat radiation fins to cool it, a ventilation duct or the like for guiding the cooling air or the like to the heat radiation fins is not required, so that the cooling structure of the battery pack 1 can be made compact. That is, the battery cooling performance can be ensured while making the cooling structure of the battery pack compact.

  Next, an embodiment shown in FIG. 4 will be described. The embodiment shown in FIG. 4 is characterized in that the battery pack 1 shown in FIG. 1 is a power source to a belt motor generator (BSG) 21 that assists driving of an engine 19 for running the vehicle 5. .

  A belt starter generator (BSG) 21 is connected to the crank pulley of the engine 19 via a belt (not shown). The BSG 21 can perform regenerative driving or power running driving according to the operating state of the engine 19. During regenerative driving, the generated power is stored in the battery module 7 of the battery pack 1 via an inverter (not shown) to perform power running driving. At times, the drive shaft of the engine 19 can be torque assisted. Therefore, when the engine is started, the BSG 21 also functions as an engine starter.

  Further, as shown in FIG. 4, the battery module 7 of the battery pack 1 is composed of, for example, a 48V battery, and the electric power charged therein is transformed into 12V via the DC-DC converter 23 and used for vehicle-mounted auxiliary equipment. The 12V battery 25 is discharged, and also the vehicle-mounted electric component 27 is discharged.

  According to the embodiment configured as described above, since the battery module 7 is a power source to the BSG 21 that assists the driving of the engine 19 of the vehicle 5, the calorific value is higher than that of the running battery of the electric vehicle. The battery pack 1 having the cooling structure shown in FIG. 1 can ensure the sufficient battery cooling performance while reducing the cost of the cooling component because the cooling capacity is less than that of the traveling battery.

  Next, an embodiment shown in FIG. 5 will be described. The embodiment shown in FIG. 5 is characterized in that the battery pack 1 shown in FIG. 1 has a coated radiation fin 31 having a light-shielding coating 29 on the surface of the radiation fin 3.

  The material of the light-shielding coating 29 is acrylic, urethane, silicon, fluorine, or the like, and a coating material made of such a material is applied.

  The application area is applied to the entire outer bottom surface 13b of the case 9 and the area including the heat radiation fins 3. The application area of the outer bottom surface 13b of the case 9 may include the side wall portion of the case 9 exposed to the outside of the vehicle. Alternatively, the heat radiation fins 3 may be applied only.

  According to the embodiment configured in this manner, it is possible to prevent the temperature of the entire bottom surface of the case 9 from rising due to radiant heat from the road surface heated by sunlight. Further, since the coated radiation fins 31 exposed to the outside of the vehicle prevent the cooling effect from being lowered by the radiant heat from the road surface, the cooling function of the battery module 7 can be ensured.

  The light-shielding coating 29 has not only a light-shielding function, that is, a function of shielding light, but also a heat-shielding function of shielding heat.

  Next, an embodiment shown in FIG. 6 will be described. The embodiment shown in FIG. 6 is characterized in that only the radiating fins 3 of the battery pack 1 shown in FIG. 1 project below the floor surface of the vehicle 5.

  The case 9 of the battery pack 1 is arranged on the floor below the passenger seat 17. That is, the entire case 9 is arranged on the indoor side of the vehicle 5, and only the portion of the radiation fin 3 projects downward from the opening formed on the floor surface and is exposed to the outside of the vehicle 5. A seal member is provided around the opening formed on the floor surface so that rainwater or the like does not enter the inside of the vehicle from the outside of the vehicle.

  According to the embodiment configured in this way, since only the heat dissipation fins 3 are exposed under the floor of the vehicle 5, a part of the case 9 is also exposed under the floor as in the embodiment of FIG. Compared with, the distance between the lower end of the radiation fin 3 and the road surface can be secured. As a result, it is possible to suppress damage to the radiation fin 3 due to contact with an obstacle or the like as much as possible, and it is possible to secure the radiation performance. Further, it is possible to reduce the possibility that the traveling property of the vehicle 5 is hindered due to the radiation fin 3 coming into contact with an obstacle or the like.

  According to at least one embodiment of the present invention, the cooling structure of the battery pack 1 can be made compact and the battery cooling performance can be secured. Therefore, a vehicle equipped with a battery pack of an electric vehicle or a travel assistance system that does not require a large electric capacity. Suitable for use in battery packs.

1 Battery Pack 3 Radiating Fins 5 Vehicle 7 Battery Module 7a Lower Surface of Battery Module 9 Case (Sheet Metal Case)
11 battery cell 13 bottom surface 13a of case 13 inner bottom surface 13b outer bottom surface 14 convex portion 15 heat transfer sheet 17 passenger seat 19 engine 21 belt motor generator (motor generator)
23 DC-DC converter 25 12V battery 27 Electrical equipment 29 Light-shielding coating 31 Radiating fin with coating

Claims (6)

A battery pack that houses a battery module and is installed in a vehicle,
A sheet metal case accommodating the battery module,
A heat transfer sheet having thermal conductivity sandwiched between the inner bottom surface of the sheet metal case and the lower surface of the battery module;
A radiating fin protruding from the outer bottom surface of the sheet metal case,
The battery pack, wherein the heat radiation fin is provided to be exposed to the outside of the vehicle.   The battery pack according to claim 1, wherein a surface of the heat dissipation fin is coated with a light-shielding coating.   The battery pack according to claim 1, wherein the heat dissipation fin is integrally formed on a bottom surface of the sheet metal case.   The heat radiation fin is provided over the entire bottom surface of the sheet metal case, and has a plurality of convex portions extending parallel to the front-rear direction of the vehicle. Battery pack described.   The battery pack according to any one of claims 1 to 4, wherein the battery module is a power source to a motor generator that assists driving of a running engine of the vehicle.   The battery pack according to any one of claims 1 to 5, wherein only the radiating fins protrude below the floor of the vehicle.

Images