Battery vehicle mounting structure

Abstract

To make it possible to reduce load inputted to a battery when load in a vehicle width direction is inputted to a vehicle.SOLUTION: A battery vehicle mounting structure includes: a battery stack 40 which is disposed between a pair of rockers 18L, 18R extended in a vehicle back and forth direction and including a plurality of battery cells; and an upper case 28 which is disposed above the vehicle of a battery stack to form a floor board of a passenger compartment, composes a part of the case housing the battery stack, and is disposed overlapping the pair of rockers. Inside the pair of rockers, a lateral wall member 18E disposed above the vehicle, higher than the battery cells, is provided. A skeleton member with a hollow structure is disposed on a vehicle upper side than the upper case, and disposed on a vehicle lower side than the upper case. A cross member 26 extended in a vehicle width direction is further provided between the pair of rockers. The skeleton member is disposed overlapping the cross member when seen from a vehicle vertical direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a vehicle battery mounting structure for mounting a plurality of battery stacks under a vehicle body. [Background technology]

[0002] In the electric vehicle described in Patent Document 1 below, a large battery unit with a battery case is mounted between left and right side members provided at the bottom of the vehicle body. This battery unit has four beam members provided on the underside of the battery case that are fixed to the left and right side members by bolts, and a front support member provided at the front end of the battery case that is fixed to the cross member by bolts. A plurality of battery modules are housed inside the battery case. Each battery module is composed of a plurality of cells connected in series. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-96789 Summary of the Invention [Problem to be solved by the invention]

[0004] The above prior art has room for improvement in terms of reducing the load input to the battery when a load is input to the vehicle in the vehicle width direction.

[0005] In consideration of the above, an object of the present invention is to provide a vehicle battery mounting structure that can reduce the load input to the battery when a load is input to the vehicle in the vehicle width direction. [Means for solving the problem]

[0006] The vehicle battery mounting structure of the invention described in claim 1 comprises a pair of rockers arranged side by side in the vehicle width direction and extending in the vehicle fore-and-aft direction, a battery stack arranged between the pair of rockers and including a plurality of battery cells stacked in the vehicle width direction, and an upper case arranged above the battery stack to form the floor of the vehicle compartment and constitute part of a case that houses the battery stack, and arranged overlapping the pair of rockers when viewed from the vehicle width direction, and inside the pair of rockers are provided lateral wall members that extend in the vehicle width direction and are arranged higher than the battery cells when viewed from the vehicle fore-and-aft direction, and a skeletal member having a hollow structure is arranged above the upper case when viewed from the vehicle width direction, and further comprises a cross member arranged lower than the upper case and extending in the vehicle width direction between the pair of rockers, and the skeletal member is arranged overlapping the cross member when viewed from the vehicle top-bottom direction.

[0007] The invention described in claim 1 includes an upper case that is disposed above the battery stack to form the floor of the vehicle and constitutes part of the case that houses the battery stack, and that is disposed so as to overlap a pair of vehicle body frame members when viewed from the vehicle width direction. As a result, when a load in the vehicle width direction is input to one of the pair of vehicle body frame members, the load is transmitted to the other vehicle body frame member via the upper case. Therefore, when a load in the vehicle width direction is input to the vehicle, the load input to the battery can be reduced.

[0008] The vehicle battery mounting structure of the invention described in claim 2 is, in claim 1, wherein each of the pair of rockers comprises an upper end wall arranged at the upper end of the vehicle, a standing wall connected to the inner side of the upper end wall in the vehicle width direction and extending in the vertical direction of the vehicle, and an inner wall connected to the standing wall and extending to the inner side of the vehicle in the vehicle width direction and arranged one step lower than the upper end wall toward the lower side of the vehicle, and the upper case is arranged to overlap the inner wall when viewed from the vertical direction of the vehicle.

[0009] The battery mounting structure for a vehicle according to the invention recited in claim 3 is the same as claim 1 or claim 2, wherein the framework member is disposed so as to overlap with the seat when viewed from the top-bottom direction of the vehicle. [Effects of the Invention]

[0010] As described above, the vehicle battery mounting structure according to the present invention can reduce the load input to the battery when a load in the vehicle width direction is input to a vehicle body frame member. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a plan view showing the configuration of a lower portion of a vehicle body of a battery-equipped vehicle to which a vehicle battery mounting structure according to an embodiment of the present invention is applied. [Figure 2] FIG. 2 is a cross-sectional view of the battery-equipped vehicle as viewed from the left side of the vehicle. [Figure 3] FIG. 2 is a perspective view showing a part of the lower part of the vehicle body shown in FIG. [Figure 4] 4 is an enlarged cross-sectional view showing a cut surface taken along line F4-F4 in FIG. 3. FIG. [Figure 5] FIG. 4 is a perspective view of FIG. 3 in which the illustration of a plurality of battery stacks is omitted. [Figure 6] FIG. 6 is a perspective view corresponding to FIG. 5, illustrating a method for mounting the battery stack. [Figure 7] FIG. 2 is an exploded perspective view of a battery stack in a partially exploded state. [Figure 8] FIG. 1 is a perspective view showing a battery-equipped vehicle according to a comparative example. [Figure 9] FIG. 10 is a perspective view showing a part of a battery pack according to a comparative example. [Figure 10] 1 is a plan view showing an example of a lower part of a vehicle body to which the vehicle battery mounting structure according to the present invention can be applied. DETAILED DESCRIPTION OF THE INVENTION

[0012] A battery mounting structure 10 for a vehicle according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7. Note that the arrows FR, UP, and LH shown as appropriate in each figure indicate the forward direction (direction of travel), upward direction, and leftward direction, respectively, of a battery-equipped vehicle 12 to which the battery mounting structure 10 for a vehicle according to this embodiment is applied. Hereinafter, when the terms front-rear, left-right, and up-down are used in the description, they will refer to front-rear in the vehicle front-rear direction, left-right in the vehicle left-right direction (vehicle width direction), and up-down in the vehicle up-down direction, unless otherwise specified. Also, in each figure, some components and some symbols may be omitted to make the drawings easier to understand.

[0013] As shown in Figures 1 and 2, a battery-equipped vehicle 12 (hereinafter simply referred to as "vehicle 12") according to this embodiment is an electric vehicle that runs using the driving force of an electric motor (not shown), and includes a sedan-type vehicle body 14. A plurality of (here, 20) battery stacks (battery modules) 40 that supply driving power to the electric motor are mounted in the lower part of this vehicle body 14. First, the configuration of the lower part of the vehicle body 14 will be described, followed by the configuration of the battery stack 40 and the mounting structure of the battery stack 40 on the vehicle body 14, which is a main part of this embodiment.

[0014] (Underbody structure) As shown in Figures 1 to 6, the vehicle body 14 includes a pair of left and right rockers 18L, 18R (see Figures 1, 3 to 6) extending in the fore-and-aft direction of the vehicle at the lower ends of the vehicle width direction of the passenger compartment 16 (see Figures 2 and 4), a front cross member 20 (see Figures 1 to 3, 5, and 6) spanning along the vehicle width direction between the front ends of the left and right rockers 18L, 18R, and a rear cross member 22 (see Figures 1 to 3, 5, and 6) spanning along the vehicle width direction between the rear ends of the left and right rockers 18L, 18R.

[0015] The vehicle body 14 also includes a center tunnel 24 (see Figures 1, 3 to 6) that extends in the vehicle longitudinal direction in the center of the vehicle width direction between the left and right rockers 18L, 18R and that spans between the front cross member 20 and the rear cross member 22. The vehicle body 14 also includes a plurality of (eight in this example) intermediate cross members (cross members) 26 (see Figures 1 to 3, 5, and 6) that are arranged side by side in the vehicle longitudinal direction between the left and right rockers 18L, 18R and the center tunnel 24 and span between the left and right rockers 18L, 18R and the center tunnel 24. The vehicle body 14 also includes a floor pan (plate) 28 (see FIGS. 2 and 4; not shown in any figures other than FIGS. 2 and 4) that spans the upper portions of the left and right rockers 18L, 18R and forms the floor surface of the vehicle interior 16, and a bottom plate 30 (see FIGS. 2, 4 to 6) that spans the lower portions (between the lower ends) of the left and right rockers 18L, 18R and forms the underside of the vehicle body 14. Above the floor pan 28, there are also provided a plurality of frame members 29 that are hollow in cross section when viewed in the vehicle width direction. The frame members 29 are arranged to overlap the seats 31 in the vehicle vertical direction when viewed in the vehicle width direction.

[0016] The rockers 18L, 18R and center tunnel 24 correspond to the "body frame members" in the present invention, and the intermediate cross member 26 corresponds to the "cross member" in the present invention. The rockers 18L, 18R and center tunnel 24 are arranged side by side in the horizontal direction of the vehicle (here, the vehicle width direction), and together with the front cross member 20, rear cross member 22 and intermediate cross member 26, they form part of the lower frame of the vehicle body 14.

[0017] The left and right rockers 18L, 18R, the front cross member 20, and the rear cross member 22 are manufactured by extrusion molding of a light metal such as an aluminum alloy. The left and right rockers 18L, 18R are formed in an elongated shape with their longitudinal direction extending in the vehicle longitudinal direction, and their cross sections, as viewed from the vehicle longitudinal direction, are generally rectangular. Each rocker 18L, 18R includes an upper end wall 18A disposed at the end of its upper side, a standing wall 18B connected to the inner side of the upper end wall 18A in the vehicle width direction and extending in the vehicle vertical direction, and a step portion (inner wall) 18C extending from the standing wall 18B toward the inner side of the vehicle in the vehicle width direction and positioned one step below the upper end wall 18A. Each rocker 18L, 18R also includes an extension wall 18D extending upward from the upper end wall 18A. Furthermore, each of the rockers 18L, 18R has a lateral wall (lateral wall member) 18E extending in the vehicle width direction when viewed from the vehicle front-rear direction. The front cross member 20 and the rear cross member 22 are formed in an elongated shape with their longitudinal direction extending in the vehicle width direction, and their cross sections when viewed from the vehicle width direction are generally rectangular. Both longitudinal ends of the front cross member 20 are joined to the front ends of the left and right rockers 18L, 18R, and both longitudinal ends of the rear cross member 22 are joined to the rear ends of the left and right rockers 18L, 18R.

[0018] The center tunnel 24 and intermediate cross member 26 are manufactured by press-forming a sheet of light metal such as an aluminum alloy. The center tunnel 24 is formed into an elongated shape with its longitudinal direction extending in the vehicle's fore-and-aft direction, and its cross section as viewed from the vehicle's fore-and-aft direction is generally hat-shaped. Both longitudinal ends of the center tunnel 24 are connected to the front cross member 20 and the rear cross member 22.

[0019] The intermediate cross members 26 are formed in an elongated shape extending in the vehicle width direction, and have a generally hat-shaped cross section when viewed in the vehicle width direction. Four intermediate cross members 26 are disposed between the left rocker 18L and the center tunnel 24, and between the right rocker 18R and the center tunnel 24. The four left and right intermediate cross members 26, the front cross member 20, and the rear cross member 22 are arranged at equal intervals in the vehicle longitudinal direction. The four intermediate cross members 26 located on the left side of the vehicle and the four intermediate cross members 26 located on the right side of the vehicle are positioned in the vehicle longitudinal direction. Both longitudinal ends of the four intermediate cross members 26 located on the left side of the vehicle are connected to the left rocker and the center tunnel 24, and both longitudinal ends of the four intermediate cross members 26 located on the right side of the vehicle are connected to the right rocker and the center tunnel 24. When viewed in the vehicle width direction, the intermediate cross members 26 are arranged to overlap some of the frame members 29 in the vehicle vertical direction.

[0020] The floor pan (upper case) 28 and the bottom plate (lower case) 30 are manufactured by press-forming a light metal plate, such as an aluminum alloy, and have a plate-like shape with the thickness direction aligned with the vehicle vertical direction. The left and right edges of the floor pan 28 overlap with step portions (inner walls) 18C formed on the upper sides of the left and right rockers 18L, 18R, as viewed from the vehicle vertical direction. More specifically, the left and right edges of the floor pan 28 abut against the step portions (inner walls) 18C from above the vehicle, and the front and rear edges of the floor pan 28 abut against the upper surfaces of the front cross member 20 and the rear cross member 22 from above the vehicle. The left and right edges of the bottom plate 30 abut against the lower surfaces of the left and right rockers 18L, 18R from below the vehicle, and the front and rear edges of the bottom plate 30 abut against the lower surfaces of the front cross member 20 and the rear cross member 22 from below the vehicle. The floor pan 28 and bottom plate 30 are connected to the left and right rockers 18L, 18R, the front cross member 20 and the rear cross member 22, and the bottom plate 30 is also connected to the center tunnel 24.

[0021] The above-described configuration of the lower part of the vehicle body 14 is one example and can be modified as appropriate. Furthermore, when the components of the lower part of the vehicle body 14 are made of the same type of light metal (e.g., aluminum alloy) as in this embodiment, the components can be joined by means of, for example, spot welding, friction stir welding, riveting, bolting, etc. Furthermore, when the components to be joined together are made of different types of materials (e.g., steel and aluminum alloy), the joining can be done by means of, for example, bolting, riveting, etc.

[0022] The left and right rockers 18L, 18R, front cross member 20, rear cross member 22, floor pan 28, and bottom plate 30 form a case that houses multiple battery stacks 40. In other words, in this embodiment, the left and right rockers 18L, 18R, front cross member 20, rear cross member 22, floor pan 28, and bottom plate 30 form a closed space (battery housing chamber) under the floor of the passenger compartment 16, and multiple battery stacks 40 are housed in this closed space. The multiple battery stacks 40 are covered from both sides in the left-right direction of the vehicle by the left and right rockers 18L, 18R, covered from both sides in the up-down direction of the vehicle by the floor pan 28 and bottom plate 30, and covered from both sides in the fore-and-aft direction of the vehicle by the front cross member 20 and rear cross member 22. The rear end of the closed space houses a junction box, a switch box, a control unit, and the like (not shown).

[0023] (Battery stack configuration) As shown in FIG. 7, the battery stack 40 is primarily composed of a plurality of stacked battery cells (storage batteries) 42, which are, for example, electrically connected in series to form a module. Note that FIGS. 1 to 3 and 6 only show a schematic representation of the battery stack 40. The stacking direction of the plurality of battery cells 42 is the vehicle width direction, which is the direction in which the left and right rockers 18L, 18R and the center tunnel 24 are aligned (facing each other). Each battery cell 42 is, for example, a lithium-ion secondary battery, and is a prismatic battery with a flat, rectangular case. A positive terminal 42A and a negative terminal 42B are provided on the top surface of each battery cell 42. Note that the type of battery cell 42 is not limited to a lithium-ion secondary battery, and may be another type, such as a nickel-metal hydride secondary battery.

[0024] An insulator 46 is sandwiched between each of the stacked battery cells 42, with the battery cells 42 and the insulators 46 stacked alternately. The insulator 46 is molded, for example, from resin and has a generally rectangular plate shape with its thickness aligned with the stacking direction. The outer periphery of the insulator 46 is provided with frame-like portions 46A that protrude in a frame shape on both sides in the stacking direction, and the battery cells 42 fit inside the frame-like portions 46A.

[0025] Furthermore, a battery cell 42 is located at each end of the stack formed by stacking the battery cells 42 and insulators 46 as described above, and end plates 48 are respectively superimposed on the battery cells 42 at each end from both outer sides in the stacking direction. Each end plate 48 is molded from resin, for example, and has a generally rectangular plate shape with its thickness direction aligned with the stacking direction.

[0026] The battery stack 40 configured as described above is formed as a long rectangular parallelepiped with its longitudinal axis extending in the vehicle width direction as a whole. In this battery stack 40, the positive electrode terminals 42A and negative electrode terminals 42B of adjacent battery cells 42 are connected to each other via bus bars (not shown) that are conductive members. Note that the configuration of the battery stack 40 is not limited to the above and can be modified as appropriate. For example, the end plates 48 may be omitted. Next, the main parts of this embodiment will be described.

[0027] (Main part of this embodiment) In this embodiment, as shown in FIGS. 1, 3, and 4, a plurality of (here, ten) battery stacks 40 are mounted (disposed) side by side in the vehicle longitudinal direction between the left rocker 18L and the center tunnel 24 and between the right rocker 18R and the center tunnel 24. Specifically, five small spaces 56 (reference numerals omitted except in FIGS. 5 and 6) are formed between the left rocker 18L and the center tunnel 24 and between the right rocker 18R and the center tunnel 24, partitioned front and rear by four intermediate cross members 26. Two battery stacks 40 are disposed (contained) side by side in the vehicle longitudinal direction in each small space 56. In the following description, the left rocker 18L and the right rocker 18R may be simply referred to as rockers 18.

[0028] Each battery stack 40 is restrained (held) to the vehicle body 14 by being directly sandwiched between the rocker 18 and the center tunnel 24. That is, each battery stack 40 is restrained to the vehicle body 14 by a pair of end plates 48 provided at both ends in the direction in which the rocker 18 and the center tunnel 24 are aligned (i.e., both longitudinal ends of each battery stack 40) abutting against the rocker 18 and the center tunnel 24. Note that the above term "sandwiched" means "pressed from both sides (in the aforementioned aligning direction) and unable to move." The above term "restraint" may be any state in which the forward / backward, left / right, up / down displacement of each battery stack 40 relative to the vehicle body 14 is restricted at least during normal traveling of the vehicle 12. Furthermore, in this embodiment, both longitudinal ends of each battery stack 40 directly abut against the rocker 18 and the center tunnel 24, but this is not limited thereto. For example, both longitudinal ends of each battery stack 40 may be configured to abut against the rocker 18 and the center tunnel 24 via plate-shaped spacers or the like, i.e., each battery stack 40 may be configured to be sandwiched between the rocker 18 and the center tunnel 24 via a separate member.

[0029] As shown in Figure 4, each battery stack 40 sandwiched between the rocker 18 and the center tunnel 24 (with both longitudinal ends abutting the rocker 18 and the center tunnel 24) as described above is subjected to a restraining force (clamping force; compressive force) F in the vehicle width direction (the stacking direction of the multiple battery cells 42) from the rocker 18 and the center tunnel 24. This restricts relative displacement of each battery stack 40 in the front-to-rear, left-to-right, and up-to-down directions with respect to the vehicle body 14. For this reason, in this embodiment, even when the bottom plate 30 and intermediate cross member 26 are removed from the vehicle body 14, each battery stack 40 remains restrained (held) by the vehicle body 14.

[0030] That is, in this embodiment, the multiple battery stacks 40 are restrained between the left and right rockers 18L, 18R and the center tunnel 24 without using dedicated restraining members (for example, brackets, fasteners, etc.). Furthermore, the multiple battery stacks 40 are mounted between the rocker 18 and the center tunnel 24 in a state where they are exposed to the space between the rocker 18 and the center tunnel 24, that is, without being housed in an outer casing (battery case). As a result, in this embodiment, the multiple battery stacks 40 are mounted over substantially the entire surface under the floor of the passenger compartment 16. The front cross member 20, rear cross member 22, and intermediate cross member 26 abut against or face the battery stacks 40 in close proximity.

[0031] In this embodiment, each battery stack 40 is mounted (inserted) from above the vehicle between the rocker 18 and the center tunnel 24 (see arrow D in FIG. 6). As shown in FIG. 6, for example, the battery stack 40 is mounted after the bottom plate 30 is attached to the lower framework of the vehicle body 14 and before the floor pan 28 is attached. When the battery stack 40 is inserted between the rocker 18 and the center tunnel 24, the battery stack 40 is compressed in the vehicle width direction (the stacking direction of the multiple battery cells 42) by a jig (not shown), for example.

[0032] (Action and effect) Next, the operation and effects of this embodiment will be described.

[0033] In the battery mounting structure 10 configured as described above, multiple battery stacks 40, each including multiple battery cells 42, are arranged side by side in the vehicle width direction between left and right rockers 18L, 18R and the center tunnel 24, which form part of the framework of the lower part of the vehicle body 14. Both ends of each battery stack 40 in the direction in which the left and right rockers 18L, 18R and the center tunnel 24 are aligned contact either one of the left and right rockers 18L, 18R and the center tunnel 24, and the battery stacks 40 are sandwiched between the left and right rockers 18L, 18R and the center tunnel 24. This restrains the multiple battery stacks 40 from being mounted on the vehicle body 14, thereby preventing dead space from being formed between the multiple battery stacks 40 and the left and right rockers 18L, 18R and the center tunnel 24. This allows for an increased mounting space for the battery stacks 40 in the lower part of the vehicle body 14.

[0034] That is, in this embodiment, the multiple battery stacks 40 are restrained between the left and right rockers 18L, 18R and the center tunnel 24 without using dedicated restraining members (e.g., brackets, fasteners, etc.), thereby eliminating the need for space for arranging the restraining members, tool clearance, etc. Furthermore, in this embodiment, the multiple battery stacks 40 are mounted between the left and right rockers 18 and the center tunnel 24 in a state where they are exposed to the space between the rockers 18 and the center tunnel 24, i.e., without being housed in an outer casing (battery case), thereby eliminating the need for mounting clearances for the battery cases and space for arranging walls of the battery cases. This makes it possible to pack more battery cells 42 into the lower part of the vehicle body 14 (here, under the floor of the passenger compartment 16), thereby increasing the capacity (amount of energy) of the batteries that can be mounted under the floor of the passenger compartment 16.

[0035] The operation and effect of this embodiment will be described in detail below using a battery-equipped vehicle 100 (comparative example) shown in Fig. 8. The battery-equipped vehicle 100 according to this comparative example (hereinafter, may be referred to as "comparative example 100") is, for example, an electric vehicle, and is configured such that a large battery pack 104 equipped with a battery case 102 is mounted under a vehicle body 106 (under the floor of the vehicle compartment). This battery pack 104 is configured as a separate entity from the vehicle body 106, and is configured to be attached to the vehicle body 106.

[0036] In this comparative example 100, wasted space is generated by mounting gaps, tool gaps, and the like for mounting the battery pack 104 on the vehicle body 106. Moreover, in this comparative example 100, as shown in Fig. 9, multiple battery stacks 108 housed in the battery case 102 are constrained (fixed) to the battery case 102 using dedicated restraint members such as brackets 110, bolts 112, and nuts 114, and therefore the space for arranging the brackets 110 and the like and tool gaps set in the battery case 102 also become wasted space. As a result, the amount of energy that can be mounted under the vehicle compartment floor is reduced, and the mass and manufacturing cost of the battery case 102 increase the mass and manufacturing cost of the battery-equipped vehicle 100.

[0037] In contrast, in this embodiment, the lower framework (underbody framework) of the vehicle body 14 is used as a restraining member for the battery stack 40, eliminating the need for mounting gaps, tool gaps, and the like as in Comparative Example 100, thereby expanding the space available for mounting the battery stack 40 (battery cells 42). This allows for an increased number of battery cells 42 to be mounted (filling rate) under the floor of the passenger compartment 16, making it possible to significantly extend the cruising range, an important performance feature for an electric vehicle, compared to Comparative Example 100. Furthermore, because the battery case 102 as in Comparative Example 100 is not required, the mass and manufacturing costs of the vehicle 12 are reduced.

[0038] Furthermore, in the comparative example 100, wasted space is generated in the vertical direction of the vehicle due to the mounting gap between the top wall 102A of the battery case 102 and the floor pan (not shown) of the vehicle body 106, the installation space of the top wall 102A, etc. As a result, the installation height of the floor pan of the vehicle body 106 increases, the hip point of the occupant increases, and the installation height of the roof 106A of the vehicle body 106 also increases. As a result, restrictions are imposed on the design of the vehicle body 106, the CD value of the vehicle body 106 deteriorates, and electricity efficiency deteriorates. If the comparative example 100 is a hybrid vehicle, fuel efficiency will also deteriorate.

[0039] On the other hand, in this embodiment, the multiple battery stacks 40 are covered from both sides in the vertical direction of the vehicle by a floor pan 28 that spans between the upper parts of the left and right rockers 18L, 18R and forms the floor surface of the passenger compartment 16, and a bottom plate 30 that spans between the lower parts of the left and right rockers 18L, 18R and forms the underside of the vehicle body 14. In other words, in this embodiment, the left and right rockers 18L, 18R, floor pan 28, and bottom plate 30, which are part of the vehicle body 14, function as a battery case that houses the multiple battery stacks 40. Therefore, compared to a configuration in which a battery case 102 that is separate from the vehicle body 106 is mounted under the floor of the passenger compartment 16 as in the comparative example 100, there is no free space under the floor of the passenger compartment 16 in the vertical direction of the vehicle. The formation of dead space can be prevented or suppressed. As a result, the vehicle 12 can be made lower, which increases the degree of freedom in designing the vehicle body 14. In addition, the hip point of the occupants can be lowered and the height of the roof 14A (see FIG. 2) can be reduced, which improves the CD value of the vehicle body 14. As a result, it is possible to improve the electricity consumption (fuel consumption if the vehicle 12 is a hybrid vehicle).

[0040] Furthermore, in the comparative example 100, the multiple battery stacks 108, which are heavy objects, are supported by the bottom plate 102B of the battery case 102, and therefore it is necessary to ensure sufficient strength and rigidity of the bottom plate 102B, which increases the mass and manufacturing costs of the bottom plate 102B. In this regard, in the present embodiment, the bottom plate 30 does not support the multiple battery stacks 40, but only needs to ensure the sealing of the underfloor space in which the multiple battery stacks 108 are housed, and therefore the bottom plate 30 can be made lightweight and low-cost.

[0041] Furthermore, in the comparative example 100, the strength of the vehicle body 14 must be designed based on collision requirements, while the strength of the battery pack 104 must be designed based on regulatory requirements, resulting in a redundant design requiring dual strength design. In this regard, in the present embodiment, the lower framework of the vehicle body 14 is utilized as a restraining member for the battery stack 40, eliminating the need for dual strength design and facilitating strength design. Moreover, for example, when a platform is shared among multiple vehicle models, it is sufficient to design the mounting structure of the battery stack 40 for each platform, which also simplifies the design. Furthermore, since the mounting position of the battery stack 40 is fixed for each platform, it is possible to reduce the number of peripheral parts required.

[0042] Furthermore, in the comparative example 100, when the heavy and large battery pack 104 is mounted on the vehicle body 106, it cannot pass through the door opening 106B of the vehicle body 106. For this reason, the battery pack 104 must be mounted on the vehicle body 106 from below, as shown in Fig. 8, which presents a problem of poor efficiency in the mounting work. In contrast, in the present embodiment, the battery stack 40 can be mounted on the lower part of the vehicle body 14 from above, as shown in Fig. 6, which improves the efficiency of the mounting work.

[0043] Furthermore, in this embodiment, the multiple battery stacks 40 located between the left and right rockers 18L, 18R and the center tunnel 24 are configured to include multiple battery cells 42 stacked in the direction in which the left and right rockers 18L, 18R and the center tunnel 24 are aligned. Therefore, when the battery stack 40 expands in the stacking direction of the multiple battery cells 42, the expansion can be suppressed by the rockers 18 and the center tunnel 24 located on both sides of the battery stack 40 in the stacking direction.

[0044] In this embodiment, multiple battery stacks 40 are arranged between the left and right rockers 18L, 18R and the center tunnel 24, and multiple intermediate cross members 26 extending in the vehicle width direction are bridged between them. This allows the multiple intermediate cross members 26 to prevent or reduce damage to the multiple battery stacks 40 in the event of a side collision of the vehicle 12. In the event of a side collision of the vehicle 12, the collision load can be transmitted to the center tunnel 24 via the intermediate cross members 26, allowing the center tunnel 24 to deform and absorb the collision load.

[0045] <Supplementary explanation of the embodiment> In the above embodiment, the present invention has been described as being applied to a vehicle 12 that is a sedan-type electric vehicle. However, the present invention is not limited to this, and can also be applied to vehicles other than sedans, hybrid vehicles, and the like. For example, FIG. 10 illustrates a portion of a vehicle body 70 of a hybrid vehicle, and the vehicle battery mounting structure of the present invention can be applied to this vehicle body 70 as well. That is, in this vehicle body 70, multiple battery stacks (not shown in FIG. 10 ) can be directly mounted between the left and right rockers 72L, 72R and the center tunnel 74 (see areas A1 to A6 surrounded by two-dot chain lines in FIG. 10 ), and the multiple battery stacks can be restrained by the left and right rockers 72L, 72R and the center tunnel 74. This enables the hybrid vehicle to be made smaller, lighter, and less expensive. In FIG. 10 , 78 denotes a floor pan, and 80 denotes a cross member.

[0046] Furthermore, in the above embodiment, the left and right rockers 18L, 18R and the center tunnel 24 are described as the "plurality of vehicle body frame members" according to the present invention. However, this is not limiting, and the present invention can also be applied to vehicles that do not have a center tunnel 24. In such a case, for example, multiple battery stacks are sandwiched between the left and right rockers and restrained by the vehicle body. Furthermore, left and right side members arranged side by side in the vehicle width direction may be configured as the "plurality of vehicle body frame members" according to the present invention, or multiple cross members arranged side by side in the vehicle longitudinal direction may be configured as the "plurality of vehicle body frame members" according to the present invention.

[0047] In addition, in the above embodiment, the front cross member 20 and the rear cross member 22 are configured to span between the front and rear ends of the left and right rockers 18L, 18R, but this is not limiting, and the front cross member 20 and the rear cross member 22 may be omitted. In this case, for example, the front and rear ends of the underfloor space (battery housing chamber) formed between the floor pan 28 and the bottom plate 30 are closed by plate-shaped closing members.

[0048] In addition, in the above embodiment, a configuration was used in which multiple intermediate cross members 26 (cross members) were spanned between the left and right rockers 18L, 18R and the center tunnel 24, but this is not limiting, and the configuration may also omit the intermediate cross members 26. Furthermore, in a vehicle that does not have a center tunnel, a configuration in which a cross member is spanned between the left and right rockers may also be used.

[0049] In the above embodiment, the plurality of battery stacks 40 are covered from both the top and bottom of the vehicle by the floor pan 28 that forms the floor surface of the vehicle interior 16 and the bottom plate 30 that forms the underside of the vehicle body 14, but this is not limiting. For example, a configuration may be adopted in which another plate-like member is interposed between the plurality of battery stacks 40 and the floor pan 28 or between the plurality of battery stacks 40 and the bottom plate 30.

[0050] In the above embodiment, the multiple battery cells 42 are stacked in the direction in which the left and right rockers 18L, 18R and the center tunnel 24 (multiple body frame members) are aligned, but this is not limiting, and the direction in which the multiple body frame members are aligned (the direction in which the multiple body frame members face each other) may be different from the stacking direction of the multiple battery cells. However, it is preferable to align the direction in which the multiple body frame members are aligned with the expansion direction of the battery stack.

[0051] Furthermore, in the above embodiment, the multiple battery stacks 40 are restrained between the left and right rockers 18L, 18R and the center tunnel 24 without using dedicated restraining members, but this is not limited to this. That is, in the invention according to claim 3, the multiple battery stacks may be restrained to the vehicle body using dedicated restraining members (brackets, fasteners, etc.). In this case, for example, each battery stack may be fixed to the left and right rockers or the center tunnel using the above-mentioned restraining members, or may be fixed to the bottom plate as described in claim 5.

[0052] In addition, the present invention can be implemented with various modifications within the scope of the gist thereof. Furthermore, it goes without saying that the scope of the rights of the present invention is not limited to the above-described embodiment. [Explanation of symbols]

[0053] 10 Battery mounting structure 12 Battery-equipped vehicles (vehicles) 14 Body 16 Cabin 18L, 18R Rocker (body frame parts) 24 Center tunnel (body frame member) 26 Intermediate cross member (cross member) 28 Floor pan (plate) (upper case) 30 Bottom plate 40 Battery Stack 42 battery cells

Claims

1. a pair of rockers arranged side by side in the vehicle width direction and extending in the vehicle front-rear direction; a battery stack disposed between the pair of rockers and including a plurality of battery cells stacked in the vehicle width direction; an upper case that is disposed above the battery stack in the vehicle, forms a floor panel of the vehicle interior, and constitutes part of a case that houses the battery stack, and is disposed so as to overlap the pair of rockers when viewed from the vehicle width direction; Equipped with a lateral wall member is provided inside the pair of rockers, the lateral wall member extending in the vehicle width direction and positioned higher than the battery cells when viewed from the vehicle front-rear direction; a frame member having a hollow structure is disposed above the upper case when viewed in the vehicle width direction, a cross member disposed below the upper case and extending in the vehicle width direction between the pair of rockers, The frame member is disposed so as to overlap the cross member when viewed from the top-bottom direction of the vehicle.

2. Each of the pair of rockers an upper end wall disposed at an end portion on the upper side of the vehicle; a standing wall connected to an inner side of the upper end wall in the vehicle width direction and extending in the vehicle up-down direction; an inner wall connected to the upright wall and extending toward the inside of the vehicle in the vehicle width direction, and disposed one step lower than the upper end wall toward the vehicle lower side, The upper case is disposed so as to overlap the inner wall when viewed from the vehicle vertical direction. The battery mounting structure for a vehicle according to claim 1.

3. The frame member is disposed so as to overlap the seat when viewed from the vehicle vertical direction.

3. A vehicle mounting structure for a battery according to claim 1.

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