Carrying structure for a vehicle battery pack

[0001] This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2006-177868, filed on Jun. 28, 2006, the disclosure of which is incorporated by reference herein in its entirety.

[0002] 1. Field of the Invention

[0003] The present invention relates to a type of carrying structure for a vehicle battery pack in an automobile equipped with a driving motor driven by the electric power from the battery pack.

[0004] 2. Description of Related Art

[0005] In recent years, automobiles having a driving motor rotated by electric power from a battery (e.g. secondary battery) as a drive source have been put into practical use. Such vehicles are driven by a driving motor rotated by the electric power from the battery. Such automobiles carry a battery pack configured by connecting plural battery modules in tandem, with each battery module including plural battery cells connected in series. For conventional automobiles, in order to make effective use of the cabin space and to improve safety in a collision, the layout is usually such that the battery pack is arranged below the rear seat (i.e. the second row of seats for vehicles having three rows of seats) on the inner cabin side of the floor panel.

[0006] However, in conventional vehicles, the rear seat (i.e. the second row of seats) is mounted on a seat rail, for sliding the seat back-and-forth inside the vehicle body, via a mounting fixture. Consequently, when battery pack maintenance or replacement operations are to be performed, a worker cannot access the battery pack unless the rear seat and seat rails are temporarily removed, making the operation difficult and inefficient.

[0007] The present invention relates to overcoming the disadvantages of the related art by providing a carrying structure for a vehicle battery pack that allows battery pack maintenance and replacement operations to be performed more easily.

[0008] In an embodiment, the invention provides a carrying structure for a vehicle battery, including a vehicle floor panel having a step portion that rises upward toward a rear of the vehicle, a battery arranged at the step portion for feeding electric power to a driving motor that drives driving wheels of the vehicle, a seat arranged above the battery, and a tip-up mechanism that enables the seat to tip up toward a front of the vehicle with a front part of the seat serving as a rotational pivot.

[0009] According to the carrying structure for a vehicle battery pack of the present invention, by tipping the seat toward the front of the vehicle via the tip-up mechanism, easy access to the battery pack arranged at the step portion is gained. As a result, battery pack maintenance and replacement operations can be performed efficiently.

[0010] In another embodiment, the invention provides a method of carrying a vehicle battery for feeding electric power to a driving motor that drives driving wheels of the vehicle, including installing the battery on a step portion of a vehicle floor panel, the step portion rising upward toward a rear of the vehicle, and disposing a seat above the battery, the seat including a tip-up mechanism that enables the seat to tip up toward a front of the vehicle with a front part of the seat serving as a rotational pivot.

[0019] FIG. 1 is a schematic side view illustrating a carrying structure for a vehicle battery pack according to an embodiment of the present invention, in connection with a hybrid automobile having three rows of seats. FIG. 2 is a schematic diagram illustrating the portion near the rear seat (i.e. the second row of seats) of the vehicle including the carrying structure for the vehicle battery pack. FIG. 3 is a cross section taken across A-A in FIG. 2. In FIGS. 1 and 2, the front of the vehicle is to the left side, and the rear of the vehicle is to the right side.

[0020] As shown in FIG. 1, vehicle 1 is a hybrid automobile that has a front seat, second-row seat (hereinafter referred to as rear seat) 3, and third-row seat 4. Battery pack 5 for feeding electric power to driving motor M that drives the driving wheels (i.e. the rear wheels in the instant embodiment) is arranged inside the cabin below the rear seat 3, and fuel tank 6 that stores fuel, such as gasoline, to be fed to the engine (not shown in the figure) is arranged outside the cabin below the rear seat 3.

[0021] Battery pack 5 is configured by connecting plural battery modules in tandem, with each battery module including plural lithium ion batteries or nickel hydrogen batteries or other suitable secondary batteries connected in series. Battery pack 5 may be formed in the shape of a quadratic prism extending along the lateral direction of the vehicle (see FIG. 3).

[0022] As shown in FIG. 2, rear seat 3 includes seat cushion 7 and seat back 8, with seat back 8 being supported by reclining mechanism 9 such that it can be rotated freely in the longitudinal direction of the vehicle. The lower portion of the front surface of seat cushion 7 of rear seat 3 is rotatable fixed by seat attachment fixture 11a arranged between seat cushion 7 and floor upper panel 10a. The lower portion of the rear surface of rear seat 3 is held in a quickly lockable/releasable way on floor upper panel 10a by seat locking member 11b. As a result, when the locking state with floor upper panel 10a is released by seat locking member 11b, with seat attachment fixture 11a serving as the rotational pivot, seat back 8 falls toward the front of the vehicle, and seat cushion 7 is lifted up, so that rear seat 3 can be folded while it is tipped up toward the front of the vehicle (see FIG. 4). In this manner, seat attachment fixture 11a and seat locking member 11b form a tip-up mechanism or a tip-up means that enables rear seat 3 to tip up toward the front of the vehicle.

[0023] As shown in FIG. 2, with respect to the positions of floor upper panel 10a and floor lower panel 10b located in front of rear seat 3, step portions 10a′, 10b′ are formed in a sloping shape that is inclined upward toward the rear of the vehicle from the front seat 2 side, such that rear seat 3 is disposed higher than front seat 2. The rear part of step portions 10a′, 10b′ is positioned nearly at the center of seat cushion 7 of rear seat 3, and floor upper panel 10a and floor lower panel 10b are arranged nearly horizontally on the floor toward the rear of the vehicle.

[0024] According to the present embodiment, a floor panel is formed by floor upper panel 10a and floor lower panel 10b. Referring to FIG. 2, the upper part of the vehicle with respect to floor lower panel 10b (as well as step portion 10b′) is the interior of the cabin, and the lower part of the vehicle with respect to floor lower panel 10b (as well as step portion 10b′) is the exterior of the cabin.

[0025] Battery pack 5 is accommodated in battery accommodating part 12 arranged between the sloping step portions 10a′, 10b′. Because battery accommodating part 12 is formed between step portions 10a′, 10b′, it is formed inclined upward and toward the rear of the vehicle, toward the region near the center of seat cushion 7 from the region near where seat attachment fixture 11a is mounted on floor upper panel 10a. A vehicle body-side connector 13 for electrically connecting to the battery-side connector (not shown in the figure) of the inserted battery pack 5 is mounted in the deeper part (toward the front of the vehicle) of battery accommodating part 12. Vehicle body-side connector 13 feeds electric power from battery pack 5 to driving motor M via wire 13a connected at one end to vehicle body-side connector 13.

[0026] Battery removal part 10c arranged on floor upper panel 10a, positioned toward the rear of the vehicle from the center of seat cushion 7, can be opened/closed freely via hinge 14.

[0027] Fuel tank 6 is attached in the region on the cabin outer side (i.e. bottom of the vehicle body) of floor lower panel 10b, below rear seat 3. Fuel tank 6 is sized appropriately so that a front portion nearer the front of the vehicle is positioned below battery accommodating part 12, and a rear portion nearer the rear of the vehicle is positioned below battery removal part 10c. Fuel pump 15 is attached near the rear of the vehicle inside fuel tank 6. Opening 10d is formed in floor lower panel 10b to the rear of step portion 10b′ in a position corresponding to that of fuel pump 15. Opening 10d is normally closed by lid 16 that can be readily removed. The upper part of fuel tank 6 toward the front of the vehicle is inclined downward toward the front of the vehicle so that it does not interfere with step portion 10b′.

[0028] As shown in FIG. 3, guide members 17a, 17b for holding the two side edge portions of battery pack 5 are respectively arranged on the two lateral sides of battery accommodating part 12 so as to guide battery pack 5 as it is accommodated in battery accommodating part 12. In this embodiment, vehicle 1 is an FR vehicle. As shown in FIG. 3, there is propeller shaft 18 connecting to the rear wheel end. In addition, part number 19 represents an exhaust pipe for exhausting combustion gases from the engine (not shown in the figure). Propeller shaft 18 and exhaust pipe 19 are arranged in the longitudinal direction of the vehicle such that they pass through the lower portion nearly at the center of a recess formed in fuel tank 6.

[0029] As shown in FIG. 2, when battery pack 5 is to be installed in battery accommodating part 12 of vehicle 1 formed between step portions 10a′, 10b′ of floor upper panel 10a and floor lower panel 10b positioned below the front part of rear seat 3, battery pack 5 is inserted with its insertion side facing obliquely downward so that it is guided by guide members 17a, 17b, and the battery-side connector (not shown in the figure) connects to the vehicle body-side connector 13. In this case, the two sides of battery pack 5 are held without play by guide members 17a, 17b.

[0030] As shown in FIG. 4, when a maintenance or replacement operation is to be performed for battery pack 5 carried in vehicle 1, seat back 8 is enabled to tip forward around the rotational pivot of seat attachment fixture 11a by unlocking seat locking member 11b from floor upper panel 10a, seat cushion 7 is raised, and rear seat 3 is folded as it is tipped up and forward. Then, battery removal part 10c arranged above the area behind battery accommodating part 12 is opened toward the front of the vehicle via hinge 14, opening the area behind battery accommodating part 12 at the top. Then, when battery pack 5 is pulled out of battery accommodating part 12 into the opened area toward the rear of the vehicle, the connection between the battery-side connector (not shown in the figure) and the vehicle body-side connector 13 is released, and battery pack 5 is removed from battery accommodating part 12 while being guided by guide members 17a, 17b.

[0031] When battery pack 5 is installed in vehicle 1, the operation is the opposite of the operation just described. That is, with rear seat 3 tipped up and forward, battery pack 5 is inserted into battery accommodating part 12 via the opened battery removal part 10c, so that while being guided by guide members 17a, 17b, the battery pack 5 moves under its own weight obliquely toward the front of the vehicle into the deeper end of battery accommodating part 12. Finally, the operator presses in battery pack 5 so that vehicle body-side connector 13 is connected to the battery-side connector (not shown in the figure). Then, as shown in FIG. 2, battery removal part 10c is closed, and rear seat 3 that has been tipped up and forward is caused to drop backward and is locked to floor upper panel 10a by seat locking member 11b.

[0032] In this case, because battery pack 5 is accommodated in battery accommodating part 12 that is inclined downward toward the front of the vehicle, the intrinsic weight of battery pack 5 is applied to vehicle body-side connector 13, so that a good connection between the vehicle body-side connector 13 and the battery-side connector (not shown in the figure) can be reliably maintained even when the vehicle body vibrates.

[0033] As explained above, according to the carrying structure for battery pack 5 of the present embodiment, battery pack 5 accommodated in battery accommodating part 12 arranged between step portions 10a′, 10b′ can be easily removed via battery removal part 10c behind battery accommodating part 12 simply by folding rear seat 3 while it is tipped up and forward. As a result, maintenance and replacement operations for battery pack 5 can be performed with ease and efficiency.

[0034] Also, as shown in FIG. 5, when battery removal part 10c is opened while rear seat 3 is tipped up and forward, and lid 16 for opening 10d positioned below battery removal part 10c is removed, the operator can easily access fuel pump 15 in fuel tank 6 through opening 10d from inside the cabin (the upper side in FIG. 5). As a result, without removing fuel tank 6, propeller shaft 18, exhaust pipe 19, etc., it is possible to perform maintenance and replacement operations for fuel pump 15 from inside the cabin with ease and efficiency.

[0035] In addition, as shown in FIG. 6(a), an inclined engagement piece 20 can be provided as a securing device on the inner side of guide member 17a toward the front of the vehicle (as well as on guide member 17b on the other side) on either side of battery accommodating part 12. As shown in FIG. 6(b), an eccentric cam 21 can be provided as a securing device on the inner side toward the front of the vehicle of guide member 17a (as well as on guide member 17b on the other side) on either side of battery accommodating part 12. Inclined portions 5a formed on the sides of battery pack 5 near the end engage with the engagement piece 20 or eccentric cam 21. As a result, battery pack 5 can be secured in battery accommodating part 12 more reliably.

[0036] Also, because rear seat 3 is mounted higher than front seat 2, it is easy to arrange step portions 10a′, 10b′ inclined upward toward the rear of the vehicle at the rear seat 3 position of floor upper panel 10a and floor lower panel 10b. As a result, by forming battery accommodating part 12 that accommodates battery pack 5 between the step portions 10a′, 10b′, the structure can be realized by minor reconfiguring, even in the case of reconfiguring a conventional gasoline vehicle or the like into a hybrid vehicle.

[0037] While the invention has been disclosed with reference to certain preferred embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the invention, as defined in the appended claims and equivalents thereof. For example, embodiments of the invention have been described in connection with a hybrid vehicle. However, the invention may be used with other vehicles such as vehicles carrying secondary batteries as in EV and fuel cell vehicles. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims.