Battery mounting structure for vehicle

Abstract

To reduce load that is input to a battery when a load is input to the vehicle in a vehicle width direction.SOLUTION: A battery mounting structure for a vehicle, the battery mounting structure includes: a pair of vehicle body frame members that is arrayed in a vehicle width direction and extends in a vehicle longitudinal direction; a cell stack 40 disposed between the pair of vehicle body frame members; and an upper case 28 that is disposed vehicle upward of the cell stack to form a floor plate of a cabin and to constitute part of a case accommodating the cell stack and is disposed while overlapping on the pair of vehicle body frame members when being viewed from the vehicle width direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vehicle mounting structure of a battery for mounting a plurality of battery stacks on the lower part of a vehicle body.

Background Art

[0002] In the electric vehicle described in Patent Document 1 below, a large battery unit having a battery case is mounted between left and right side members provided at the lower part of the vehicle body. Four girder members provided on the lower surface of the battery case of this battery unit are fixed to the left and right side members by bolt fastening, and a front support member provided at the front end of the battery case is fixed to the cross member by bolt fastening. A plurality of battery modules are housed inside this battery case. Each battery module is configured by connecting a plurality of cells in series.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above prior art, there is room for improvement in reducing the load input to the battery when a load in the vehicle width direction is input to the vehicle.

[0005] In consideration of the above facts, an object of the present invention is to obtain a vehicle mounting structure of a battery capable of reducing the load input to the battery when a load in the vehicle width direction is input to the vehicle.

Means for Solving the Problems

[0006] The vehicle-mounted structure of the battery according to the invention described in claim 1 includes a pair of vehicle body frame members arranged side by side in the vehicle width direction and extending in the vehicle front-rear direction, a battery stack arranged between the pair of vehicle body frame members, and an upper case arranged above the battery stack in the vehicle to form a floor board of the passenger compartment and constituting a part of a case for housing the battery stack, and when viewed from the vehicle width direction, the upper case is arranged overlapping the pair of vehicle body frame members.

[0007] The invention described in claim 1 includes an upper case arranged above the battery stack in the vehicle to form a floor surface of the vehicle and constituting a part of a case for housing the battery stack, and when viewed from the vehicle width direction, the upper case is arranged overlapping a pair of vehicle body frame members. Thereby, 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. For this reason, 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-mounted structure of the battery according to the invention described in claim 2, in claim 1, the pair of vehicle body frame members are a pair of rockers extending in the vehicle front-rear direction.

[0009] The vehicle-mounted structure of the battery according to the invention described in claim 3, in claim 2, each of the pair of rockers includes a transverse wall member extending in the vehicle width direction inside.

[0010] The vehicle-mounted structure of the battery according to the invention described in claim 4, in claim 3, each of the pair of rockers includes a plurality of transverse wall members extending in the vehicle width direction and arranged side by side in the vehicle vertical direction inside.

[0011] The vehicle-mounted structure of the battery according to the invention described in claim 5, in claim 4, each of the pair of rockers includes an upper end wall disposed at an end on the upper side of the vehicle, a standing wall connected to the inside in the vehicle width direction of the upper end wall and extending in the vehicle up-and-down direction, and an inner wall connected to the standing wall and extending toward the inside of the vehicle in the vehicle width direction and disposed one step lower than the upper end wall on the lower side of the vehicle. The upper case is disposed so as to overlap the inner wall when viewed from the vehicle up-and-down direction.

[0012] The vehicle-mounted structure of the battery according to the invention described in claim 6, in claim 5, further includes a lower case disposed on the lower side of the vehicle than the battery stack and constituting a part of the case for housing the battery stack. Each of the pair of rockers includes an extending wall extending from the upper end wall toward the upper side of the vehicle. The lower case is fastened to each of the pair of rockers inside the vehicle width direction rather than the extending wall when viewed from the vehicle up-and-down direction. The vehicle-mounted structure of the battery according to the invention described in claim 7, in claim 6, a skeletal member having a hollow structure is disposed on the upper side of the vehicle than the upper case when viewed from the vehicle width direction. The vehicle-mounted structure of the battery according to the invention described in claim 8, in claim 7, further includes a cross member disposed on the lower side of the vehicle than the upper case and extending in the vehicle width direction between the pair of rockers. The skeletal member is disposed so as to overlap the cross member when viewed from the vehicle up-and-down direction. The vehicle-mounted structure of the battery according to the invention described in claim 9, in claim 8, the skeletal member is disposed so as to overlap the seat when viewed from the vehicle up-and-down direction.

Advantages of the Invention

[0013] As described above, the vehicle-mounted structure of the battery according to the present invention can reduce the load input to the battery when a load in the vehicle width direction is input to the vehicle body skeletal member.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0015] The vehicle-mounted structure 10 of the battery according to the embodiment of the present invention will be described with reference to FIGS. 1 to 7. In addition, the arrows FR, UP, and LH appropriately shown in each figure indicate the front direction (travel direction), the upward direction, and the left direction of the battery-mounted vehicle 12 to which the vehicle-mounted structure 10 of the battery according to the present embodiment is applied, respectively. Hereinafter, when simply explaining using the front-rear, left-right, and up-down directions, unless otherwise specified, the front and rear in the vehicle front-rear direction, the left and right in the vehicle left-right direction (vehicle width direction), and the up and down in the vehicle up-down direction are shown. Also, in each figure, for the sake of easy viewing of the drawing, the illustration of some members and some reference numerals may be omitted.

[0016] As shown in FIGS. 1 and 2, the battery-mounted vehicle 12 (hereinafter abbreviated as "vehicle 12") according to the present 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 (here, 20) of battery stacks (battery modules) 40 that supply driving power to the above electric motor are mounted below the vehicle body 14. First, the configuration of the lower part of the vehicle body 14 will be described, and then the configuration of the battery stack 40 and the mounting structure of the battery stack 40 on the vehicle body 14, which is the main part of the present embodiment, will be described.

[0017] (Configuration of the lower part of the vehicle body) As shown in FIGS. 1 to 6, the above vehicle body 14 includes a pair of left and right rockers 18L and 18R (see FIGS. 1, 3 to 6) extending in the vehicle longitudinal direction at both lower ends in the vehicle width direction of the passenger compartment 16 (see FIGS. 2 and 4), a front cross member 20 (see FIGS. 1 to 3, 5, 6) spanned in the vehicle width direction between the front end portions of the left and right rockers 18L and 18R, and a rear cross member 22 (see FIGS. 1 to 3, 5, 6) spanned in the vehicle width direction between the rear end portions of the left and right rockers 18L and 18R.

[0018] In addition, this vehicle body 14 has a center tunnel 24 (see FIGS. 1, 3 to 6) that extends in the vehicle longitudinal direction at the center in the vehicle width direction between the left and right rockers 18L and 18R and is spanned between the front cross member 20 and the rear cross member 22. Further, this vehicle body 14 has a plurality (here, eight) of intermediate cross members (cross members) 26 (see FIGS. 1 to 3, 5, 6) that are arranged side by side in the vehicle longitudinal direction between the left and right rockers 18L and 18R and are spanned between the left and right rockers 18L and 18R and the center tunnel 24. Also, this vehicle body 14 has a floor pan (plate material) 28 (see FIGS. 2, 4; not shown in FIGS. 2, 4 and other figures) that is spanned between the upper portions of the left and right rockers 18L and 18R to form the floor surface of the passenger compartment 16, and a bottom plate 30 (see FIGS. 2, 4 to 6) that is spanned between the lower portions (lower end portions) of the left and right rockers 18L and 18R to form the lower surface of the vehicle body 14. Further, above the floor pan 28, there are a plurality of skeletal members 29 that are hollow in cross section when viewed from the vehicle width direction. The plurality of skeletal members 29 are arranged so as to overlap the seat 31 in the vehicle vertical direction when viewed from the vehicle width direction.

[0019] The above-described rockers 18L, 18R and center tunnel 24 correspond to the "vehicle body skeletal members" in the present invention, and the above-described intermediate cross members 26 correspond to the "cross members" in the present invention. The rockers 18L, 18R and center tunnel 24 are arranged side by side in the vehicle horizontal direction (here, the vehicle width direction), and together with the above-described front cross member 20, rear cross member 22 and intermediate cross members 26, they constitute a part of the skeleton at the lower part of the vehicle body 14.

[0020] 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, for example. The left and right rockers 18L, 18R are formed in a long shape with the longitudinal direction of the vehicle as the longitudinal direction, and the cross section viewed from the longitudinal direction of the vehicle is substantially rectangular. Each of the rockers 18L, 18R is provided with an upper end wall 18A disposed at the upper end portion, a standing wall 18B connected to the inner side in the vehicle width direction of the upper end wall 18A and extending in the vehicle up-and-down direction, and a stepped portion (inner side wall) 18C extending from the standing wall 18B to the inner side of the vehicle in the vehicle width direction and disposed one step lower than the upper end wall 18A. Further, each of the rockers 18L, 18R includes an extending wall 18D extending upward from the upper end wall 18A. Furthermore, each of the rockers 18L, 18R includes a transverse wall (transverse wall member) 18E extending in the vehicle width direction when viewed from the longitudinal direction of the vehicle. The front cross member 20 and the rear cross member 22 are formed in a long shape with the vehicle width direction as the longitudinal direction, and the cross section viewed from the vehicle width direction is substantially rectangular. Both longitudinal ends of the front cross member 20 are coupled to the front end portions of the left and right rockers 18L, 18R, and both longitudinal ends of the rear cross member 22 are coupled to the rear end portions of the left and right rockers 18L, 18R.

[0021] The center tunnel 24 and the intermediate cross member 26 are manufactured by press molding a plate material made of a light metal such as an aluminum alloy, for example. The center tunnel 24 is formed in a long shape with the longitudinal direction of the vehicle as the longitudinal direction, and the cross section viewed from the longitudinal direction of the vehicle is substantially hat-shaped. Both longitudinal ends of the center tunnel 24 are coupled to the front cross member 20 and the rear cross member 22.

[0022] The intermediate cross member 26 is formed in a long shape with the vehicle width direction as the longitudinal direction, and the cross section viewed from the vehicle width direction is substantially hat-shaped. Between the left rocker 18L and the center tunnel 24 and between the right rocker 18R and the center tunnel 24, there are four intermediate cross members The cross members 26 are arranged. The four intermediate cross members 26 on each of the left and right sides, the front cross member 20, and the rear cross member 22 are arranged at equal intervals in the vehicle longitudinal direction. Also, 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 in the same position in the vehicle longitudinal direction. The longitudinal ends of the four intermediate cross members 26 located on the left side of the vehicle are coupled to the left rocker and the center tunnel 24, and the longitudinal ends of the four intermediate cross members 26 located on the right side of the vehicle are coupled to the right rocker and the center tunnel 24. Further, the intermediate cross member 26 is arranged so as to overlap with some of the skeletal members 29 in the vehicle vertical direction when viewed from the vehicle width direction.

[0023] The floor pan (upper case) 28 and the bottom plate (lower case) 30 are manufactured by press-forming a plate material made of a light metal such as an aluminum alloy, and have a plate shape with the vehicle vertical direction as the plate thickness direction. The left and right edge portions of the floor pan 28 are arranged to overlap with the stepped portions (inner walls) 18C formed on the upper sides of the left and right rockers 18L and 18R when viewed from the vehicle vertical direction. More specifically, the left and right edge portions of the floor pan 28 are in contact with the stepped portions (inner walls) 18C from above the vehicle, and the front and rear edge portions of the floor pan 28 are in contact with the upper surfaces of the front cross member 20 and the rear cross member 22 from above the vehicle. The left and right edge portions of the bottom plate 30 are in contact with the lower surfaces of the left and right rockers 18L and 18R from below the vehicle, and the front and rear edge portions of the bottom plate 30 are in contact with the lower surfaces of the front cross member 20 and the rear cross member 22 from below the vehicle. These floor pan 28 and bottom plate 30 are coupled to the left and right rockers 18L and 18R, the front cross member 20, and the rear cross member 22, and the bottom plate 30 is also coupled to the center tunnel 24.

[0024] Incidentally, the configuration of the lower part of the vehicle body 14 described above is an example and can be changed as appropriate. Also, when the constituent members of the lower part of the vehicle body 14 are made of the same type of light metal (for example, an aluminum alloy) as in the present embodiment, as the joining method of each constituent member, for example, means such as spot welding, friction stir joining, riveting, and bolt fastening can be used. Further, when the constituent members to be joined to each other are made of different types of materials (for example, steel and an aluminum alloy), as the joining method, for example, means such as bolt fastening and riveting can be used.

[0025] The left and right rockers 18L and 18R, the front cross member 20, the rear cross member 22, the floor pan 28, and the bottom plate 30 constitute a case that houses a plurality of battery stacks 40. That is, in the present embodiment, a closed space (battery housing chamber) is formed under the floor of the passenger compartment 16 by the left and right rockers 18L and 18R, the front cross member 20, the rear cross member 22, the floor pan 28, and the bottom plate 30, and a plurality of battery stacks 40 are housed in the closed space. The plurality of battery stacks 40 are covered from both sides in the vehicle left-right direction by the left and right rockers 18L and 18R, covered from both sides in the vehicle up-down direction by the floor pan 28 and the bottom plate 30, and covered from both sides in the vehicle front-rear direction by the front cross member 20 and the rear cross member 22. Incidentally, a junction box, a switch box, a control unit, etc. (not shown) are housed on the rear end side of the closed space.

[0026] (Configuration of Battery Stack) As shown in FIG. 7, the battery stack 40 is mainly composed of a plurality of stacked battery cells (storage batteries) 42, and the plurality of battery cells 42 are modularized by being electrically connected in series, for example. Note that FIGS. 1 to 3 and FIG. 6 schematically illustrate the battery stack 40. The stacking direction of the plurality of battery cells 42 is the vehicle width direction in which the left and right rockers 18L and 18R and the center tunnel 24 are arranged (the direction in which they face each other). Each battery cell 42 is, for example, a lithium-ion secondary battery and is a rectangular battery having a flat rectangular parallelepiped case. On the upper surface of each battery cell 42, a positive electrode terminal 42A and a negative electrode terminal 42B are provided. Note that the type of the battery cell 42 is not limited to a lithium-ion secondary battery and may be other types such as a nickel-metal hydride secondary battery.

[0027] Insulators 46 are sandwiched between the plurality of stacked battery cells 42, and the battery cells 42 and the insulators 46 are alternately stacked. The insulator 46 is, for example, formed of resin and has a substantially rectangular plate shape with the stacking direction as the thickness direction. On the outer peripheral edge of the insulator 46, a frame-shaped portion 46A protruding in a frame shape to both sides in the stacking direction is provided, and the battery cell 42 is fitted inside the frame-shaped portion 40A.

[0028] Also, battery cells 42 are located at both ends of the laminate in which the battery cells 42 and the insulators 46 are stacked as described above, and end plates 48 are overlapped on the battery cells 42 at both ends from both outer sides in the stacking direction. Each end plate 48 is, for example, formed of resin and has a substantially rectangular plate shape with the stacking direction as the thickness direction and is formed.

[0029] The battery stack 40 configured as described above is formed in an overall long rectangular parallelepiped shape with the vehicle width direction as its longitudinal direction. 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 a bus bar (not shown) which is a conductive member. Note that the configuration of the battery stack 40 is not limited to the above and can be changed as appropriate. For example, the configuration in which the end plate 48 is omitted may be adopted. Next, the main part of the present embodiment will be described.

[0030] (Main part of the present embodiment) In the present embodiment, as shown in FIGS. 1, 3, and 4, a plurality (here, 10) of battery stacks 40 are mounted (arranged) side by side in the vehicle front-rear direction between the left rocker 18L and the center tunnel 24, and between the right rocker 18R and the center tunnel 24, respectively. Specifically, between the left rocker 18L and the center tunnel 24, and between the right rocker 18R and the center tunnel 24, five small spaces 56 (reference numerals omitted except in FIGS. 5 and 6) partitioned front and rear by four intermediate cross members 26 are formed, respectively. And in each small space 56, two battery stacks 40 are arranged (accommodated) side by side in the vehicle front-rear direction. Note that in the following description, the left rocker 18L and the right rocker 18R may be simply referred to as the rocker 18.

[0031] Each battery stack 40 is restrained (held) by 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 by 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 "sandwiched" means "being pressed from both sides (in the above-aligned direction) and being in a state where it cannot move." The above "restrained" only needs to be such that at least during normal running of the vehicle 12, the displacement of each battery stack 40 in the front-rear, left-right, and up-down directions with respect to the vehicle body 14 is restricted. Also, in the present embodiment, both longitudinal ends of each battery stack 40 are directly abutting against the rocker 18 and the center tunnel 24, but it is not limited thereto. For example, a configuration in which both longitudinal ends of each battery stack 40 abut against the rocker 18 and the center tunnel 24 via a plate-shaped spacer or the like, that is, a configuration in which each battery stack 40 is sandwiched between the rocker 18 and the center tunnel 24 via another member may be employed.

[0032] As described above, each battery stack 40 sandwiched between the rocker 18 and the center tunnel 24 (both longitudinal ends of which abut against the rocker 18 and the center tunnel 24) receives a restraining force (clamping force; compressive force) F in the vehicle width direction (the stacking direction of the plurality of battery cells 42) from the rocker 18 and the center tunnel 24 as shown in FIG. 4. Thereby, the relative displacement of each battery stack 40 in the front-rear direction, left-right direction, and up-down direction with respect to the vehicle body 14 is restricted. For this reason, in the present embodiment, even when the bottom plate 30 and the intermediate cross member 26 are removed from the vehicle body 14, each battery stack 40 is configured to maintain the state of being restrained (held) by the vehicle body 14.

[0033] That is, in the present embodiment, the plurality of battery stacks 40 are constrained between the left and right rockers 18L and 18R and the center tunnel 24 without using a dedicated constraint member (e.g., bracket, fastener, etc.). Further, the plurality of battery stacks 40 are each mounted between the rocker 18 and the center tunnel 24 in a state of being exposed in the space between the rocker 18 and the center tunnel 24, that is, in a state of not being housed in the housing (battery case) serving as the outer shell. Thereby, in the present embodiment, a configuration is adopted in which a plurality of battery stacks 40 are mounted on substantially the entire floor under the passenger compartment 16. Note that the front cross member 20, the rear cross member 22, and the intermediate cross member 26 are in contact with or close to and opposed to the battery stack 40.

[0034] Further, in the present embodiment, each battery stack 40 is configured to be mounted (inserted) between the rocker 18 and the center tunnel 24 from above the vehicle (see arrow D in FIG. 6). The mounting of the battery stack 40 is performed, for example, after the bottom plate 30 is attached to the lower skeleton of the vehicle body 14 and before the floor pan 28 is attached, as shown in FIG. 6. Further, when the battery stack 40 is inserted between the rocker 18 and the center tunnel 24, for example, the battery stack 40 is configured to be compressed in the vehicle width direction (the stacking direction of the plurality of battery cells 42) by a jig (not shown).

[0035] (Operation and Effect) Next, the operation and effect of the present embodiment will be described.

[0036] In the vehicle-mounted structure 10 of the battery having the above-described configuration, a plurality of battery stacks 40 each including a plurality of battery cells 42 are arranged between the left and right rockers 18L and 18R and the center tunnel 24 that are arranged side by side in the vehicle width direction and form part of the skeleton at the lower part of the vehicle body 14. Both ends of these battery stacks 40 in the direction in which the left and right rockers 18L and 18R and the center tunnel 24 are arranged are in contact with either one of the left and right rockers 18L and 18R and the center tunnel 24, and are sandwiched between the left and right rockers 18L and 18R and the center tunnel 24. Thereby, since the plurality of battery stacks 40 are restrained by the vehicle body 14, it is possible to prevent a wasteful space (dead space) from being formed between the plurality of battery stacks 40 and the left and right rockers 18L and 18R and the center tunnel 24. Therefore, the mounting space for the battery stacks 40 at the lower part of the vehicle body 14 can be expanded.

[0037] That is, in the present embodiment, since the plurality of battery stacks 40 are restrained between the left and right rockers 18L and 18R and the center tunnel 24 without using a restraint member dedicated for restraint (for example, a bracket, a fastener, etc.), the space for arranging the restraint member and the tool clearance, etc. are not required. Further, in the present embodiment, since the plurality of battery stacks 40 are mounted between the left and right rockers 18 and the center tunnel 24 in a state of being exposed in the space between the rocker 18 and the center tunnel 24, that is, in a state of not being housed in a housing (battery case) serving as an outer shell, the mounting clearance of the battery case and the space for arranging the wall portion of the battery case, etc. are not required. Thereby, it becomes possible to pack more battery cells 42 in the lower part of the vehicle body 14 (here, the floor of the passenger compartment 16), and the capacity (energy amount) of the battery that can be mounted under the floor of the passenger compartment 16 can be increased.

[0038] The operation and effects 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, sometimes 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.

[0039] In this comparative example 100, wasted space is generated due to 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 restrained (fixed) to the battery case 102 using brackets 110, bolts 112, nuts 114, and the like, which are restraining members dedicated to restraint, so that the arrangement space for the brackets 110 and the like set in the battery case 102, tool gaps, and the like 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-equipped vehicle 100 increase due to the mass and manufacturing cost of the battery case 102.

[0040] In contrast, in this embodiment, the lower frame of the vehicle body 14 (underbody frame) is Since it is utilized as a restraining member for the tack 40, mounting gaps and tool gaps as in Comparative Example 100 are not required, and the mounting space for the battery stack 40 (battery cells 42) is expanded. This makes it possible to increase the number of battery cells 42 mounted (filling rate) under the floor of the passenger compartment 16, making it possible to significantly extend the cruising distance, which is an important performance for an electric vehicle, compared to Comparative Example 100. Moreover, since the battery case 102 as in Comparative Example 100 is not required, the mass and manufacturing costs of the vehicle 12 are reduced.

[0041] In Comparative Example 100, due to the mounting gap set between the top wall 102A of the battery case 102 and the floor pan (not shown) of the vehicle body 106, and the arrangement space of the top wall 102A, etc., wasted space is also generated in the vehicle vertical direction. For this reason, the arrangement height of the floor pan of the vehicle body 106 increases, the hip point of the occupant becomes higher, and the arrangement height of the roof 106A of the vehicle body 106 also increases. As a result, there are restrictions on the design of the vehicle body 106, the CD value of the vehicle body 106 deteriorates, and the power consumption deteriorates. In addition, when Comparative Example 100 is a hybrid vehicle, the fuel consumption deteriorates.

[0042] On the other hand, in the present embodiment, a floor pan 28 that is bridged between the upper parts of the left and right rockers 18L and 18R to form the floor surface of the passenger compartment 16, and a bottom plate 30 that is bridged between the lower parts of the left and right rockers 18L and 18R to form the lower surface of the vehicle body 14, cover a plurality of battery stacks 40 from both sides in the vehicle vertical direction. That is, in the present embodiment, the left and right rockers 18L and 18R, the floor pan 28, and the bottom plate 30, which are part of the vehicle body 14, function as a battery case that houses a plurality of battery stacks 40. For this reason, compared with the configuration in which a battery case 102 separate from the vehicle body 106 is mounted under the passenger compartment floor as in Comparative Example 100, it is possible to prevent or suppress the formation of wasted space in the vehicle vertical direction under the passenger compartment 16. As a result, the vehicle 12 can be made lower-floor, so the degree of freedom in the design of the vehicle body 14 is improved. In addition, it is possible to lower the hip point of the occupant and lower the arrangement height of the roof 14A (see FIG. 2), so the CD value of the vehicle body 14 can be improved. As a result, the power consumption (fuel consumption when the vehicle 12 is a hybrid vehicle) can be improved.

[0043] In Comparative Example 100, since a plurality of battery stacks 108, which are heavy objects, are supported by the bottom plate 102B of the battery case 102, it is necessary to sufficiently ensure the strength and rigidity of the bottom plate 102B, resulting in an increase in the mass and manufacturing cost of the bottom plate 102B. In this regard, in the present embodiment, the bottom plate 30 does not support the plurality of battery stacks 40, and it is only necessary to ensure the sealing performance of the underfloor space in which the plurality of battery stacks 108 are accommodated. Therefore, the bottom plate 30 can be made lightweight and low-cost.

[0044] In Comparative Example 100, while the vehicle body 14 is designed for strength based on collision requirements, the battery pack 104 needs to be designed for strength based on regulatory requirements, resulting in a dual strength design and thus a redundant design. In this regard, in the present embodiment, since the lower skeleton of the vehicle body 14 is utilized as a restraint member for the battery stack 40, a dual strength design is not required, and the strength design becomes easier. Moreover, for example, when the platform is shared among a plurality of vehicle models, it is only necessary to design the mounting structure of the battery stack 40 for each platform, which also simplifies the design. Furthermore, by fixing the mounting position of the battery stack 40 for each platform, it is also possible to reduce the types of peripheral components.

[0045] In Comparative Example 100, when mounting the heavy and large-sized battery pack 104 on the vehicle body 106, it is impossible to pass through the door opening 106B of the vehicle body 106. Therefore, as shown in FIG. 8, the battery pack 104 has to be mounted on the vehicle body 106 from below, resulting in a problem of poor mounting work efficiency. In contrast, in the present embodiment, as shown in FIG. 6, the battery stack 40 can be mounted on the lower part of the vehicle body 14 from above, so that the mounting work efficiency can be improved.

[0046] In addition, in the present embodiment, a plurality of battery stacks 40 positioned between the left and right rockers 18L and 18R and the center tunnel 24 are configured to include a plurality of battery cells 42 stacked in the direction in which the left and right rockers 18L and 18R and the center tunnel 24 are arranged. Therefore, when the battery stack 40 expands in the stacking direction of the plurality of 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.

[0047] In addition, in the present embodiment, a plurality of battery stacks 40 are arranged between the left and right rockers 18L and 18R and the center tunnel 24, and a plurality of intermediate cross members 26 extending in the vehicle width direction are spanned therebetween. Thereby, damage to the plurality of battery stacks 40 during a side collision of the vehicle 12 can be prevented or suppressed by the plurality of intermediate cross members 26. Further, during a side collision of the vehicle 12, a collision load can be transmitted to the center tunnel 24 via the intermediate cross member 26, so that the collision load can be absorbed by the deformation of the center tunnel 24.

[0048] <Supplementary Explanation of the Embodiment> In the above embodiment, the case where the present invention is applied to the vehicle 12 which is a sedan type electric vehicle has been described. However, the present invention is not limited to this, and the present invention is also applicable to vehicles other than sedan types and hybrid vehicles. For example, although a part of the vehicle body 70 of a hybrid vehicle is shown in FIG. 10, the vehicle-mounted structure of the battery according to the present invention can also be applied to this vehicle body 70. That is, also in this vehicle body 70, a plurality of battery stacks (not shown in FIG. 10) may be directly mounted between the left and right rockers 72L and 72R and the center tunnel 74 (see regions A1 to A6 surrounded by a two-dot chain line in FIG. 10), and the plurality of battery stacks may be restrained by the left and right rockers 72L and 72R and the center tunnel 74. Thereby, weight reduction and cost reduction of the hybrid vehicle can be realized. In FIG. 10, 78 is a floor pan and 80 is a cross member.

[0049] In the above-described embodiment, the case where the left and right rockers 18L and 18R and the center tunnel 24 are the "plurality of vehicle body frame members" according to the present invention has been described. However, the present invention is not limited to this, and the present invention is also applicable to a vehicle not provided with the center tunnel 24. In that case, for example, a plurality of battery stacks are sandwiched between the left and right rockers and are constrained by the vehicle body. Further, the 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 a plurality of 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.

[0050] In the above-described embodiment, the front cross member 20 and the rear cross member 22 are bridged between the front end portions and the rear end portions of the left and right rockers 18L and 18R. However, the present invention is not limited to this, and the front cross member 20 and the rear cross member 22 may be omitted. In that case, for example, the front end portion and the rear end portion of the underfloor space (battery housing chamber) formed between the floor pan 28 and the bottom plate 30 are closed by plate-like closing members.

[0051] In the above-described embodiment, a plurality of intermediate cross members 26 (cross members) are bridged between the left and right rockers 18L and 18R and the center tunnel 24. However, the present invention is not limited to this, and the intermediate cross members 26 may be omitted. Further, in a vehicle not provided with a center tunnel, a cross member may be bridged between the left and right rockers.

[0052] In the above-described embodiment, a plurality of battery stacks 40 are covered from both sides in the vehicle up-and-down direction by the floor pan 28 forming the floor surface of the passenger compartment 16 and the bottom plate 30 forming the lower surface of the vehicle body 14. However, the present invention is not limited thereto. For example, another plate-like member may be 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. A configuration 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 may be employed.

[0053] In the above-described embodiment, the plurality of battery cells 42 are stacked in the direction in which the left and right rockers 18L and 18R and the center tunnel 24 (a plurality of vehicle body frame members) are arranged. However, the present invention is not limited to this, and the direction in which the plurality of vehicle body frame members are arranged (the facing direction of the plurality of vehicle body frame members) and the stacking direction of the plurality of battery cells may be different. However, it is preferable to align the direction in which the plurality of vehicle body frame members are arranged with the expansion direction of the battery stack.

[0054] In the above-described embodiment, the plurality of battery stacks 40 are constrained between the left and right rockers 18L and 18R and the center tunnel 24 without using a dedicated constraint member. However, the present invention is not limited to this. That is, in the invention according to claim 3, the plurality of battery stacks may be configured to be constrained to the vehicle body using dedicated constraint members (such as brackets and fasteners). In that case, for example, each battery stack may be fixed to the left and right rockers or the center tunnel using the above-described constraint members, or may be fixed to the bottom plate described in claim 5.

[0055] In addition, the present invention can be implemented with various modifications without departing from the gist thereof. Needless to say, the scope of the rights of the present invention is not limited to the above-described embodiment.

Explanation of Reference Numerals

[0056] 10 Battery mounting structure 12 Battery-mounted vehicle (vehicle) 14 Vehicle body 16 Passenger compartment 18L, 18R Rocker (vehicle body frame member) 24 Center tunnel (vehicle body frame member) 26 Intermediate cross member (cross member) 28 Floor pan (plate material) (upper case) 30 Bottom plate 40 Battery stack 42 Battery cell

Claims

1. A pair of vehicle body frame members arranged side by side in a vehicle width direction and extending in a vehicle front-rear direction; a battery stack disposed between the pair of vehicle body frame members; an upper case that is disposed above the battery stack in the vehicle to form a floor panel of a vehicle compartment and that constitutes a part of a case that houses the battery stack, the upper case being disposed so as to overlap with the pair of vehicle body frame members when viewed from the vehicle width direction; A vehicle mounting structure for a battery comprising:

2. The pair of vehicle body frame members are a pair of rockers extending in the vehicle front-rear direction. A vehicle mounting structure for a battery according to claim 1.

3. Each of the pair of rockers includes a lateral wall member extending in the vehicle width direction therein. A vehicle mounting structure for a battery according to claim 2.

4. Each of the pair of rockers includes a plurality of the side wall members extending in a vehicle width direction therein and arranged side by side in a vehicle up-down direction. A vehicle mounting structure for a battery according to claim 3.

5. Each of the pair of rockers is An upper end wall disposed at an end portion on an upper side of the vehicle; a vertical 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 vertical 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 with the inner wall when viewed from the vehicle top-bottom direction. A vehicle mounting structure for a battery according to claim 4.

6. a lower case that is disposed below the battery stack and that constitutes a part of a case that houses the battery stack; Each of the pair of rockers includes an extension wall extending from the upper end wall toward the upper side of the vehicle, The lower case is fastened to each of the pair of rockers on a vehicle width direction inner side of the extension wall when viewed from the vehicle up-down direction. A vehicle mounting structure for a battery according to claim 5.

7. A framework member having a hollow structure is disposed above the upper case when viewed from the vehicle width direction. A vehicle mounting structure for a battery according to claim 6.

8. a cross member disposed below the upper case and extending in a vehicle width direction between the pair of rockers, The framework member is disposed so as to overlap with the cross member when viewed from the vehicle vertical direction. A vehicle mounting structure for a battery according to claim 7.

9. The framework member is disposed so as to overlap with the seat when viewed from the top-bottom direction of the vehicle. A vehicle mounting structure for a battery according to claim 8.

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