Battery pack cooling structure

Abstract

To improve air circulation efficiency inside a sealed-type battery pack to achieve simplified structure, uniform temperature distribution inside the battery pack, and expected cooling effects.SOLUTION: A plurality of battery modules (31, 32) are provided inside a battery case. The battery case includes lateral surfaces (151, 261) inclined such that a width of a front side is narrower than a width of a rear part in a vehicle longitudinal direction in a plan view, and includes a blower fan (5) to draw air inside the battery case through an inlet (50) and to pressure-feed the air to outlets (45) through a blower duct (4). The inlet (50) is opened in a portion that is a middle part in a width direction in the rear part of the battery case and that is above a first group of battery modules (31). The outlets (45) are arranged adjacent to lateral surfaces of the rear part of the battery case and oriented in a front direction, and forms a blowout air flow (Fa) blowing forward along the inclined lateral surfaces (151, 261) of the battery case.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a cooling structure for a battery pack mounted in a vehicle. [Background technology]

[0002] In a battery pack mounted on a vehicle, for example, a battery pack for an electric vehicle, a plurality of modules each made up of a plurality of secondary batteries are arranged inside a flat case and placed on the floor of the vehicle or under the floor in order to increase the capacity while ensuring the space inside the vehicle and in the luggage compartment. Since the secondary batteries generate heat during charging and discharging, the battery pack is provided with a cooling structure.

[0003] Cooling structures for battery packs include an open type that introduces outside air and a sealed type that uses a heat pump; however, the former has issues with the intrusion of rainwater and dust, while the latter requires a compressor and radiator outside the battery pack (see Patent Document 1). As a result, the cooling system cannot be completed by the battery pack alone, making the system complicated and posing issues such as condensation water generated in the internal evaporator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-11632 A Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, a method is being reconsidered in which a blower fan is provided inside a sealed battery pack to make the temperature distribution inside the battery pack uniform while efficiently dissipating heat from the battery case, which serves as a heat dissipation member, to the outside.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to improve the air circulation efficiency inside the battery pack, simplify the structure, uniformize the temperature distribution inside the battery pack, and achieve the desired cooling effect. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides A cooling structure for a battery pack including a plurality of battery modules inside a substantially sealed battery case, The battery case has a side surface that is inclined in a plan view so that the width of the front side is narrower than the rear side in the vehicle length direction, and has a function as a heat dissipation member by being formed substantially of a thermally conductive material. The battery case has a blower fan that draws in air inside the battery case from an intake port and pressure-blows it to an outlet port through an air duct, the plurality of battery modules include a first battery module group fixedly arranged with a gap between them at the rear part inside the battery case, and a second battery module group fixedly arranged with a gap between them forward in the vehicle length direction from the first battery module group, the second battery module group being arranged side by side with their longitudinal directions aligned with the vehicle length direction; The intake port is opened above the first battery module group at a middle portion in a width direction of the rear portion of the battery case, and The cooling structure for the battery pack is configured so that the air outlet includes left and right air outlets arranged adjacent to the rear side of the battery case and oriented forward, and a forward-facing airflow is formed along the inclined side of the battery case. Effect of the Invention

[0008] With the above-described configuration of the cooling structure of the battery pack according to the present invention, air (air heated by heat exchange with the battery module group) drawn in from the middle of the battery module group at the rear of the case is pressurized by the blower fan to left and right air outlets located adjacent to the side faces of the rear of the battery case and oriented forward, forming an airflow blown forward along the inclined side faces of the battery case, and heat is dissipated to the outside through heat exchange with the side faces of the battery case. The cooled blown air is circulated inside the battery case and passed through the gaps between the battery modules (mainly the longitudinal gaps) and is sucked and collected into the intake port of the blower fan, cooling the battery modules and promoting heat dissipation to the outside through heat exchange with the top surface of the battery case.

[0009] In other words, air circulation and heat transfer are induced between the sides and peripheral parts of the battery case, which are heat dissipation areas due to thermal conduction via the mounting structure on the vehicle body and contact with the outside air, and the middle parts of the battery modules, where heat tends to build up, thereby suppressing temperature rise in the battery modules and making the temperature distribution more uniform.

[0010] Furthermore, the configuration in which air is blown out from an air outlet located adjacent to the side of the rear of the battery case and oriented forward allows the space on the side of the battery case to function as an air passage that also serves as a heat exchange area, making it possible to circulate cooling air over a wide area within the battery case with a minimum of air duct, which is advantageous for making the duct smaller, simplifying the device, and reducing costs. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view showing the appearance of the battery pack. [Diagram 2] FIG. 2 is a perspective view showing the inside of the battery pack. [Diagram 3] FIG. 2 is a plan view showing the inside of the battery pack. [Figure 4] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 5] FIG. 4 is a plan view showing the air flow inside the battery pack. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0013] (Battery pack overview) 1, a battery pack 1 according to an embodiment of the present invention is designed to be mounted under the floor of a vehicle and has an overall flat shape except for a rear bulge 12. In the following description, unless otherwise specified, "front and rear" refers to the front and rear sides in the vehicle length direction FR, "left and right" refers to the left and right sides in the vehicle width direction W toward the forward vehicle length direction F, and "up and down" corresponds to the top and bottom sides in the vehicle height direction H.

[0014] 1 to 4, the battery pack 1 includes a plurality of battery modules 31, 32 inside a battery case consisting of an upper case 10 and a lower case 20. Each battery module 31, 32 is modularized by holding a plurality of secondary battery cells (lithium ion secondary batteries, etc.) connected in series with each other in a stacked state inside a box-shaped or frame-shaped inner case.

[0015] The upper case 10 and the lower case 20 are formed into a shell or tray shape using press-molded parts made of metal with good thermal conductivity, such as steel, stainless steel, or an aluminum alloy, and they themselves function as heat dissipation members to the outside.

[0016] 1, an upper case 10 constituting the upper portion of the battery pack 1 has a ridge 13 formed in the center in the vehicle width direction W on an upper surface 11 extending from the front to the rear in the vehicle length direction, the ridge 13 extending in the vehicle length direction FR, and three small ridges (reinforcing beads) extending parallel to the vehicle length direction FR on each of the left and right sides. Also, a meeting portion 14 between the ridge 13 and the front inclined surface 122 of the bulge 12 is formed in a funnel shape that rises and widens toward the bulge 12.

[0017] The top surface 11 of the upper case 10 has the ridges 13 and small ridges described above, but is generally flat overall, whereas a bulge 12 that bulges upward is formed in the rear of the upper case 10 to be accommodated in the lower space of the kick-up section under the rear seat of the vehicle. The internal space expanded upward by this bulge 12 is an installation space for the ventilation duct 4 and ventilation fan 5 that constitute the cooling system, and also serves as a heat dissipation space separated from the battery modules 31 and 32, as described below.

[0018] The battery pack 1 is configured such that the battery modules 31, 32 and their control devices are housed in the lower case 20, and components such as the ventilation duct 4 and ventilation fan 5 that constitute the cooling system are arranged and the necessary wiring is completed. The flange portion 20f around the lower case 20 and the flange portion 10f of the upper case 10 are joined together with bolts or the like via sealing material 20c to ensure waterproofing and airtightness.

[0019] A support frame 25 that serves as a support frame for the battery pack 1 is fixed to the underside of the lower case 20. Although detailed illustration is omitted, the support frame 25 is configured in a ladder shape by a pair of left and right side frames 250 and a plurality of cross frames 255 (FIG. 4) that extend between and are rigidly connected to the pair of left and right side frames 250 in the vehicle width direction W.

[0020] The battery pack 1 is provided with four mounting brackets 21, 22, 23, and 24 on each of the left and right sides as mounting portions to the vehicle body. Of these, the mounting brackets 22, 23, and 24 excluding the frontmost one are composed of an upper bracket joined to a flange portion 10f of the upper case 10 of the battery pack 1 and a lower bracket joined to a flange portion 20f of the lower case 20. The battery pack 1 is fixed to the vehicle body by fastening bolts inserted from below through bolt holes in each mounting bracket 21, 22, 23, and 24 to weld nuts of the mounting portions on the vehicle body side.

[0021] In the battery pack 1, a high-voltage connector 33 for inputting and outputting power to the vehicle drive motor is disposed on the front end surface of the lower case 20, and a high-voltage connector 36 for charging is disposed on the rear surface of the upper case 10 (bulge 12). A service plug 34 for cutting off power to the battery modules 31, 32 during inspection or in an emergency is disposed on the top surface 11 of the upper case 10, and a control connector 35 is disposed on the top surface 121 of the bulge 12 of the upper case 10. The battery modules 31, 32, together with a junction box to which the high-voltage connectors 33, 36 are connected and the service plug 34, are connected in series by a bus bar, a part of which is indicated by reference numeral 39 in FIG. 3.

[0022] (Battery module placement) 2 and 3, inside the battery pack 1, four battery modules 32 (32a, 32j) are arranged side by side at the forefront with their respective longitudinal directions aligned with the vehicle length direction FR and with gaps 320 between them. Behind them, in the middle of the battery pack 1, four battery modules 32 (32b) are arranged in a similar arrangement, spaced apart from the four battery modules 32 (32a, 32j) with gaps 322 extending in the vehicle width direction. That is, the four battery modules 32 (32b) in the middle are arranged side by side with their respective longitudinal directions aligned with the vehicle length direction FR and with gaps 320 between them.

[0023] In the illustrated example, the second module 32j from the right at the front is a junction box equipped with a relay circuit that supplies / cuts off power to the high-voltage connector 33, but for example, this function can be consolidated into a junction box 38 in the bulge 12 to form a battery module, and for convenience it will be described as battery module 32.

[0024] At the rear inside the battery pack 1, four battery modules 31 (31c, 31d) are arranged side by side with their respective longitudinal directions aligned with the vehicle width direction W and with gaps 310, 312 between them, with a gap 330 between them and the intermediate battery module 32b, as shown by the dashed lines in Fig. 3. Of these, the two left-hand battery modules 31d have fewer sets of secondary battery cells than the other battery modules, and are half-size modules with shorter longitudinal lengths.

[0025] The battery modules 31, 32 are fixed to reinforcing frames 27a, 27b, 27c, 28a, 28b arranged on the inner bottom of the lower case 20. That is, the front and middle battery modules 32 are fixed with bolts at both front and rear ends in the longitudinal direction to reinforcing frames 27a, 27b, 27c arranged at three locations from the front to the middle of the inner bottom of the lower case 20 at a distance in the longitudinal direction and extending in the vehicle width direction W. The four rear battery modules 31 are fixed with bolts at both left and right ends in the longitudinal direction to reinforcing frames 28a, 28b arranged at a distance in the rear both sides and the middle of the inner bottom of the lower case 20 at a distance in the longitudinal direction.

[0026] In the following description, the four battery modules 31 (31c, 31d) at the rear of the battery pack 1 may be collectively referred to as the first battery module group 31, and the eight battery modules 32 (32a, 32b) at the front and middle of the battery pack 1 described above may be collectively referred to as the second battery module group 32.

[0027] (Battery pack side shape) As described above, the battery pack 1 has a planar shape that is longer in the vehicle length direction FR than in the vehicle width direction W, assuming that it will be mounted under the vehicle body. However, as shown in Figures 3 and 5, the battery pack 1 has inclined side surfaces (151, 261, 153, 263) in a planar view so that the width at the front side is narrower than the rear side in the vehicle length direction, thereby forming a tapered shape.

[0028] That is, as shown in FIG. 1 or FIG. 5, the side of the upper case 10 of the battery pack 1 includes a rear side 150 that is not inclined in a planar view and extends substantially parallel to the vehicle length direction, a first inclined side 151 that is continuous with the front side of the rear side, a middle side 152 that is not inclined in a planar view and is continuous with the front side of the rear side, and a second inclined side 153 that is continuous with the front side of the rear side, and the width of the upper case 10 gradually decreases in steps from the rear to the front in the vehicle length direction.

[0029] Similarly, the side surfaces of the lower case 20 also include a rear side surface 260 that is not inclined in a planar view and extends substantially parallel to the vehicle length direction, a first inclined side surface 261 that is continuous with the front side of the rear side surface 260, a middle side surface 262 that is continuous with the front side of the rear side surface 260 and is not inclined in a planar view, and a second inclined side surface 263 that is continuous with the front side of the rear side surface 260, and the width of the lower case 20 gradually decreases in steps from the rear to the front in the vehicle length direction.

[0030] 3 and 5, due to the side shape as described above, side spaces 321, 323 that gradually narrow in stages from the rear to the front in the vehicle length direction are formed between the outermost battery module 32 (32a, 32b) in the second battery module group 32 and the side surfaces (150-153, 260-263) of the battery pack 1. Based on this configuration, the cooling system described below is configured.

[0031] (Battery module cooling system) As shown in Figures 2 to 4, a support plate 17 for arranging the air duct 4 and the air fan 5 that constitute the cooling system is provided on the upper side of the four battery modules 31 arranged at the rear of the battery pack 1.

[0032] The support plate 17 is fixed to the reinforcing frame 28a on both sides in the vehicle width direction via legs 18. The legs 18 are formed of inverted U-shaped members formed by bending downward both ends of a frame material extending in the vehicle width direction W along the lower surface of the support plate 17, and each lower end (flange portion) is fixed to the reinforcing frame 28a with a bolt.

[0033] The support plate 17 is extended to a height approximately equal to the upper surface 11 of the upper case 10, with a gap between it and the upper surface of the battery module 31, and is arranged to separate the internal space of the bulge portion 12 of the upper case 10 from the lower battery module 31 side, except for an opening 170 approximately in the center and the peripheral portion, and there is a gap between the side surface 150 and the rear surface 155 of the bulge portion 12.

[0034] As shown in Figures 3, 4 and 5, the opening 170 of the support plate 17 is opened above the intersection of a gap 310 extending in the vehicle width direction W midway between the first battery module group 31 at the rear of the battery pack 1 and a gap 312 extending in the vehicle length direction between the end faces of the left and right battery modules 31c, 31d of the first battery module group 31.

[0035] A blower fan 5 is disposed approximately in the center of the support plate 17 in the vehicle width direction W. A centrifugal fan (sirocco fan or turbo fan) can be suitably used as the blower fan 5, and it is fixed to the support plate 17 with bolts or the like, with its rotational axis direction coinciding with the vehicle height direction H and with an intake port 50 at the bottom of the fan case facing an opening 170 of the support plate 17. In the illustrated example, a sirocco fan is used in which the motor is disposed inside the fan hub, thereby reducing the upward protrusion of the motor housing.

[0036] A control device 37 for managing the charging and discharging of the battery and controlling cell balance is provided on the right side of the blower fan 5, and a junction box 38 for the high-voltage connector 36 is provided on the left side of the blower fan 5. Along the front edge of the support plate 17 in front of these, a blower duct 4 (branch duct portion 42) is provided.

[0037] As shown in Figures 2 to 4, the air duct 4 includes a base 41 extending forward (diagonally forward) from the exhaust port 54 of the air blower fan 5, a branch duct portion 42 branching off at the front end of the base 41 and extending to both the left and right sides, and a descending portion 44 extending downward from a bent portion 43 adjacent to the rear side surfaces 150, 260 of the battery case 1, and is connected to an air outlet 45 that extends forward from the lower part of the base 41 and opens forward.

[0038] The branch duct section 42 has an approximately pentagonal or trapezoidal flow path cross section including an inclined surface at the front upper part so as to follow the inclined surface 122 of the bulge section 12, whereas the descending section 44 is formed flat in the vehicle width direction while its width in the vehicle length direction expands rearward to ensure a flow path cross section similar to that of the branch duct section 42, and the outlet 45 has a vertically elongated nozzle shape that is flat in the vehicle width direction.

[0039] (Air circulation and cooling effect inside the battery pack) In the cooling system configured as described above, when the blower fan 5 is operated, air that has been heated by heat exchange with each battery module 31c, 31d at the rear of the battery pack 1 is sucked and collected into the intake port 50 via the opening 170, and is pressurized and sent from the base 41 of the blower duct 4 through the branch duct portion 42 to the descending portion 44, and is blown forward from the air outlets 45 on each of the left and right sides, as shown by the arrows Fa in Figure 3.

[0040] The air blown out from the air outlets 45 on each of the left and right sides flows forward (Fa) along the rear side surfaces 150, 260, as shown in FIG. 3 (and FIG. 5), is deflected inward (Fb) at the first inclined side surfaces 151, 261, and advances through the side space 321 between the battery module 32b.

[0041] At this time, the blown air is cooled by contact (heat exchange) with the rear side surfaces 150, 260 or the first inclined side surfaces 151, 261 of the battery pack 1, and the cooled air advances further through the side space 323 (Fc), is further cooled by contact (heat exchange) with the middle side surfaces 152, 262 or the second inclined side surfaces 153, 263, and flows into the front space 324.

[0042] On the other hand, a portion of the airflow that is deflected inward at the first inclined side surfaces 151, 261 and moves forward through the side space 321 also flows into the gap 322 of the battery modules 32a, 32b that branches inward from the side space 323 on an extension of the deflection direction (Fb).

[0043] Due to the air blown forward from the left and right side air outlets 45 as described above, the peripheral areas (321, 323, 324) of the second battery module group 32 (32a, 32b) inside the battery pack 1 become relatively positive pressure areas. On the other hand, the gaps 310, 312 of the first battery module group 31 (31c, 31d) where suction (Fr) to the intake port 50 by the blower fan 5 occurs and their surroundings become relatively negative pressure areas.

[0044] As a result, in the gaps 320 of the three rows in the vehicle length direction of the second battery module group 32 (32a, 32b), which are located halfway between the relative positive pressure areas (321, 323, 324) and the negative pressure areas (310, 312), an airflow is generated toward the rear as shown in FIG. 5, and returns to the negative pressure areas (310, 312) via the gaps 330 in the vehicle width direction.

[0045] So, to summarise the above: (i) The air heated by heat exchange with the first battery module group 31 is sucked and collected through the intake port 50 of the blower fan 5, thereby cooling the first battery module group 31; (ii) The heated air that has been sucked and collected is pressure-fed through the air duct 4, blown forward from the air outlet 45, and cooled by heat exchange with the side surfaces (150, 260, 151, 261, 152, 262) of the battery pack 1. (iii) The second battery module group 32 is cooled by heat exchange during the process of the cooled air circulating to the rear of the battery pack through the gaps 320, 322, 330, and 312, (iv) In parallel with the above, heat dissipation to the outside air and the vehicle body structure is promoted via upper case 10 and lower case 20, including the side surfaces (150, 260, 151, 261, 152, 262) of battery pack 1.

[0046] In particular, by using a configuration in which air is sucked in by a blower fan 5 located approximately in the center of the rear of the battery pack and blown out from air outlets 45 located on both sides of the rear of the battery pack, it is possible to generate overall air circulation inside the battery pack through the side spaces (321, 323), the front space (324), and the gaps (320, 322, 330, 310, 312) of the battery pack, while using an air duct 4 that is small compared to the size of the battery pack 1. This makes it possible to cool the battery modules 31, 32, to equalize the temperature distribution, and to achieve air cooling through heat exchange using the side surfaces (150, 260, 151, 261, 152, 262) of the battery pack 1 and dissipate heat to the outside.

[0047] Furthermore, the second battery module group 32 includes a front battery module group 32a arranged side by side at the front of the battery case (10, 20) in the vehicle length direction, and a middle battery module group 32b aligned behind it and arranged side by side between the first battery module group, and the first inclined side surfaces 151, 261 extend laterally of the lateralmost battery module 32b, so that, as already described, the air blown forward from the air outlets 45 on each of the left and right sides is guided by the first inclined side surfaces 151, 261 and deflected inward (Fb) and moves forward through the side space 321 between the lateralmost battery module 32b.

[0048] More precisely, the high-speed blown airflow flows along the first inclined side 151, 261, causing an induced airflow on the inside in the vehicle width direction, and as this induced airflow flows along the side of the battery module 32b, the heat of the battery module 32b is recovered by the induced airflow.

[0049] The air then merges with the blown air flow that has been cooled by heat exchange with the first inclined side surface 151, 261 and flows further forward, but as it moves forward of the first inclined side surface 151, 261, the flow path cross-sectional area of ​​the side space 321 decreases, thereby suppressing a decrease in flow rate, and the air reaches the branch point with the gap 322 while maintaining the flow rate.

[0050] Here, some of the air flows into the gap 322, but because the flow rate is maintained, the remaining air flows into the side space 323, and in this process, heat is recovered from the outermost battery module 32a and dissipated to the outside through heat exchange with the middle sides 152, 262 and the second inclined sides 153, 263.

[0051] In addition, heat from the battery modules 32 near the center and not adjacent to the sides 15, 26 of the battery case (10, 20) is recovered by an airflow flowing backward along the gap 320 caused by the pressure gradient between the relative positive pressure areas (321, 323, 324) and negative pressure areas (310, 312) mentioned above, and is sucked into the intake port 50 of the blower fan 5 together with the heat from the first battery module group 31 via the gap 330 and the gap 312.

[0052] In other words, the air in the gap 320 is replaced with air cooled by heat exchange at the side surfaces 15, 26 and front end surfaces 154, 264 of the battery case (10, 20), thereby cooling the battery modules 32 near the center.

[0053] As described above, the cooling system of the present invention basically only sucks and collects air that has been heated inside the battery case (10, 20) through the intake port 50 of the blower fan 5 located approximately in the center of the rear of the battery pack, pressurizes it through the blower duct 4 to both sides in the vehicle width direction, and blows it forward from the exhaust port 45. However, by utilizing the side spaces 321, 323 that are extensions of this as an air supply path that also serves as a heat dissipation area to the outside air and the vehicle structure through the side surfaces 15, 26 of the battery case (10, 20) and a cooling area for the blown air, it is possible to expect a uniform cooling effect and temperature distribution of the battery modules 31, 32.

[0054] As already mentioned, the side surfaces 15, 26 of the battery case (10, 20) are provided with mounting brackets 21, 22, 23, 24 that serve as mounting parts for the battery pack 1 to the vehicle body, and blowing air into the side spaces 321, 323 is advantageous not only in terms of heat dissipation to the outside air, but also in terms of heat dissipation to the vehicle body structure.

[0055] In the above embodiment, the first battery module group 31 includes four battery modules 31c, 31d oriented in the vehicle width direction, and the second battery module group 32 includes four front battery modules 32a and four middle battery modules 32b oriented in the vehicle length direction. However, the number of battery modules may be other than the above as long as the respective arrangement directions are maintained.

[0056] In the above embodiment, the blower duct 4 and the blower fan 5 are installed on the support plate 17 having the opening 170 below the suction port 50, but they may be installed on a frame-like support structure. However, if the upper parts of the gaps 310, 312 are open inside the bulging portion 12, the gaps 310, 312 cannot function as suction ducts, and therefore at least the area from the periphery of the suction port 50 to the upper parts of the gaps 310, 312 must be shielded (although not completely) by a member on the plate or the like.

[0057] Also, in the above embodiment, the case has been described in which the intake port 50 of the blower fan 5 (fan case) faces the opening 170 of the support plate 17, thereby separating the fan case from the support plate 17. This configuration is advantageous in preventing the vibration of the blower fan 5 from being transmitted to the support plate 17, but the gap around the intake port 50 and the opening 170 may be sealed with a vibration insulating member such as an elastic seal member.

[0058] In the above embodiment, the intake port 50 and the opening 170 of the blower fan 5 are disposed above the intersection of the vehicle width direction gap 310 and the vehicle length direction gap 312 of the first battery module group 31, but the intake port 50 and the opening 170 may be disposed above the vehicle length direction gap 312 at a position shifted forward or rearward of the intersection. In cases such as when the intake port 50 and the opening 170 are disposed forward of the intersection, the blower duct 4 may be configured to branch off from behind the blower fan 5 in the vehicle length direction.

[0059] In addition, in the above embodiment, the side surfaces 15, 26 of the battery case (10, 20) are described as including a first inclined side surface 151, 261 and a second inclined side surface 153, 263 that are inclined in a planar view, and an intermediate side surface 152, 262 that is not inclined in a planar view between them. However, depending on the arrangement of the second battery module group 32, it is also possible to have only one inclined side surface that includes a section of the first inclined side surface 151, 261.

[0060] Although the embodiment of the present invention has been described above, it should be noted that the present invention is not limited to the above embodiment, and various modifications and variations are possible within the scope of the present invention. [Explanation of symbols]

[0061] 1 Battery pack 4. Air duct 5. Blower fan 10 Upper Case 11 Top side 12 Bulge 15,26 Side 17 Support Plate 18 Legs 20 Lower case 31, 31c, 31d Battery modules (first battery module group) 32, 32a, 32b Battery modules (second battery module group) 41 Base 42 Branch duct section 43 Bend 44 Descending section 45 Air outlet 50 Intake port 51 Motor 54 Discharge port 150,260 Rear side 151,261 1st inclined side 152,262 Middle side 153,263 2nd inclined side 154,264 Front end surface 155,265 Rear 170 Opening 310,312,320,322,330 gap 321,323 Side space 324 Front Space

Claims

1. A cooling structure for a battery pack including a plurality of battery modules inside a substantially sealed battery case, The battery case has a side surface that is inclined in a plan view so that the width of the front side is narrower than the rear side in the vehicle length direction, and has a function as a heat dissipation member by being formed substantially of a thermally conductive material. The battery case has a blower fan that draws in air inside the battery case from an intake port and pressure-blows it to an outlet port through an air duct, the plurality of battery modules include a first battery module group fixedly arranged in the rear part of the battery case with a gap therebetween, and a second battery module group fixedly arranged forward in the vehicle length direction from the first battery module group with a gap therebetween, the second battery module group being arranged side by side with their longitudinal directions aligned with the vehicle length direction, The intake port is opened above the first battery module group at a middle portion in a width direction of the rear portion of the battery case, and The cooling structure for a battery pack, wherein the air outlet includes left and right air outlets arranged adjacent to the rear side of the battery case and oriented forward, and wherein an air outlet flow directed forward along the inclined side of the battery case is formed.

2. the second battery module group includes a front battery module group arranged side by side at a front portion of the battery case in a vehicle length direction, and a middle battery module group arranged side by side in an aligned manner behind the front battery module group, 2 . The cooling structure for a battery pack according to claim 1 , wherein the inclined side surface of the battery case includes a first inclined side surface extending laterally of the middle battery module group.

3. 3. The cooling structure for a battery pack according to claim 2, wherein the first battery module group includes a left side battery module group and a right side battery module group arranged side by side with their longitudinal directions aligned in the vehicle width direction and aligned with each other, and the intake port opens above an intersection of a gap extending in the vehicle width direction between each of the left side battery module group and the right side battery module group and a gap extending in the vehicle length direction between each end face of the left side battery module group and the right side battery module group.

4. 3. The cooling structure for a battery pack as described in claim 2, wherein the side surface of the battery case includes, on the side of the front battery module group, an intermediate side surface that is substantially non-inclined in a planar view and continues to the front side of the first inclined side surface, and a second inclined side surface that continues to the front side of the intermediate side surface, and the second inclined side surface is continuous to the front end surface of the battery case.

5. 4. The cooling structure for a battery pack according to claim 3, wherein a bulge that bulges upward is formed at a rear portion in the vehicle length direction of the upper surface of the battery case, a support plate extending along the upper surface of the first battery module group is provided inside the bulge, the blower fan is fixedly positioned on the support plate with the intake port facing downward, and an opening is formed in the support plate above the intersection in an area facing the intake port.

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