Battery pack protection structure

Abstract

This battery pack protection structure comprises: a cross member (20) that has a bent part (2A), formed along a corner part (17) of a case (12) of a battery pack (10), and an inner part (2B), extending inward in the vehicle width direction from the bent part (2A) along a bottom surface (15), and that extends along the vehicle width direction; a first reinforcement (40) that is superposed with the cross member (20) along the bent part (2A) and positioned on at least one of the upper side or the lower side of the cross member (20); and a second reinforcement (50) that has a first segment (51) overlapping at least a portion of a segment, formed along the bent part (2A), of the first reinforcement (40) in plan view, and a second segment (52) extending inward in the vehicle width direction from the first segment (51) and overlapping at least a portion of an inner part (2B) in plan view, and that is superimposed with the cross member (20) and positioned on at least one of the upper side or the lower side of the cross member (20).

Description

Battery pack protection structure

[0001] The present invention relates to a battery pack protection structure for protecting a battery pack mounted in a vehicle.

[0002] A vehicle is provided with body structures (framework members) such as cross members extending along the vehicle width direction and side members extending along the vehicle front-rear direction. Such body structures are also applied to electric vehicles (such as electric vehicles and hybrid electric vehicles) equipped with a battery pack as a power source for driving the vehicle. The battery pack contains a secondary battery module in an internal space formed by attaching a cover (lid) to a case (also called a casing or tray). For example, Patent Document 1 proposes a structure for a vehicle equipped with a battery pack in which a cross member extends along the bottom and side surfaces of the tray. In this structure, the cross member is assembled along a corner formed by the bottom surface of the case and the side surface located outside the vehicle width direction of the case.

[0003] Japanese Patent Application Laid-Open No. 2020-155341

[0004] However, because corners of the case of an in-vehicle battery pack are prone to deformation due to external forces acting along the vehicle width direction, a cross member bent along the corners alone may not be sufficient to prevent such deformation. For example, when a vehicle is involved in a side collision, an impact is applied from the outside to the inside of the vehicle width direction, which may cause deformation of the corners of the case and may also cause deformation of the bottom surface of the case extending in the vehicle width direction. As a result, the inability to prevent deformation of the corners and bottom surface of the case, which should be prevented, may result in insufficient protection for the battery pack. Therefore, there is room for improvement in ensuring the protection of the battery pack.

[0005] The battery pack protective structure of the present invention was invented in light of these problems, and one of its objectives is to ensure the protection of the battery pack. However, in addition to this objective, another objective of the present invention is to achieve the effects derived from the configurations shown in the "Description of Embodiments" below, which are not obtainable with conventional technology.

[0006] The disclosed battery pack protective structure can be realized as the following disclosed embodiments (application examples) and solves at least part of the above-mentioned problems. Each of the embodiments from embodiment 2 onwards is an embodiment that can be selected as an additional option, and each of the embodiments from embodiment 2 onwards is an embodiment that can be omitted. None of the embodiments from embodiment 2 onwards discloses an embodiment or configuration that is essential to the present invention.

[0007] Aspect 1. The disclosed battery pack protective structure includes a cross member, a first reinforcement, and a second reinforcement. The cross member has a bent portion that follows a corner formed by the bottom surface of a battery pack case mounted on a vehicle and a side surface located at a vehicle width direction end of the case, and an inner portion that extends from the bent portion along the bottom surface toward the vehicle width direction inward, and extends along the vehicle width direction. The first reinforcement is overlapped with the cross member along the bent portion on at least one of the upper and lower sides of the cross member. The second reinforcement has a first portion that overlaps at least a portion of the portion of the first reinforcement that follows the bent portion in a plan view, and a second portion that extends from the first portion toward the vehicle width direction inward and overlaps at least a portion of the inner portion in a plan view, and is overlapped with the cross member on at least one of the upper and lower sides of the cross member.

[0008] Aspect 2. In the above-mentioned aspect 1, it is preferable that the first portion has a side portion extending along the side surface. Aspect 3. In the above-mentioned aspect 1 or 2, it is preferable that the first reinforcement and the second reinforcement are arranged in the order of the first reinforcement and the second reinforcement from the cross member side.

[0009] Aspect 4. In any one of Aspects 1 to 3 above, it is preferable that the first reinforcement has an upper first reinforcement arranged on the upper side of the cross member and a lower first reinforcement arranged on the lower side of the cross member, and the second reinforcement has an upper second reinforcement arranged on the upper side of the cross member and a lower second reinforcement arranged on the lower side of the cross member.

[0010] Aspect 5. In any one of Aspects 1 to 4 above, it is preferable that the second portion includes a portion that overlaps with the battery module housed in the case in a plan view. Aspect 6. In any one of Aspects 1 to 5 above, it is preferable that the battery pack protective structure includes a side member that extends in the fore-and-aft direction of the vehicle along the side surface and is attached across a plurality of the cross members that are arranged side by side at intervals in the fore-and-aft direction.

[0011] Aspect 7. In the above-mentioned Aspect 6, it is preferable that the battery pack protective structure includes a third reinforcement overlapped along the side member. Aspect 8. In any one of the above-mentioned Aspects 1 to 7, it is preferable that the cross member has a pair of flange portions extending to the front and rear of the vehicle, respectively, a bottom portion extending between the pair of flange portions and positioned lower than the pair of flange portions, and a wall portion vertically connecting each of the pair of flange portions and the bottom portion, and the first reinforcement is formed along the bottom portion and the wall portion.

[0012] Aspect 9. In any one of Aspects 1 to 8 above, it is preferable that the first reinforcement has ribs that extend along the vehicle width direction and protrude downward on each of the front and rear sides of the vehicle. Aspect 10. In any one of Aspects 1 to 9 above, it is preferable that the cross member, the first reinforcement, and the second reinforcement are provided only on the outside of the case.

[0013] According to the disclosed battery pack protective structure, the protection of the battery pack can be ensured.

[0014] Fig. 1 is a perspective view showing a battery pack and its peripheral configuration of a battery pack protective structure according to an embodiment. Fig. 2 is an exploded perspective view showing a case of the battery pack of Fig. 1 and its peripheral members in an exploded state. Fig. 3 is an exploded perspective view showing a main part of a structure for reinforcing the battery pack of Fig. 1. Fig. 4 is a longitudinal sectional view showing a main part of the battery pack protective structure of Fig. 1.

[0015] An embodiment of a battery pack protective structure will be described with reference to the drawings. The embodiment described below is merely an example, and is not intended to exclude various modifications or applications of techniques not explicitly described in the embodiment. The configurations of the embodiment can be modified in various ways without departing from the spirit of the embodiment. Furthermore, they can be selected or combined as needed.

[0016] In the following description, the forward direction of the vehicle is defined as the front, and the backward direction as the rear, and left and right are defined based on the front. Since the left and right direction is the width direction of the vehicle, in this embodiment, the left and right direction is referred to as the "vehicle width direction" of the vehicle. Furthermore, the up and down direction is defined with the direction of gravity as the downward direction and the opposite direction as the upward direction. A view from above or below (i.e., a view along the up and down direction) is called a plan view, and a view from the right or left (i.e., a view along the vehicle width direction) is called a side view. Note that the up and down direction does not have to completely coincide with the vertical direction and may be slightly inclined relative to the vertical direction. Similarly, the front and back direction of the vehicle (hereinafter simply referred to as the "front and back direction") and the vehicle width direction do not have to completely coincide with the horizontal direction.

[0017] Vehicle structures are often formed with near bilateral symmetry (mirror symmetry with respect to a plane including the yaw axis and roll axis passing through the center of gravity of the vehicle), but perfect symmetry is not required. Furthermore, the type of vehicle to which the structure according to the embodiment is applied is not particularly limited as long as it is equipped with at least a battery pack. For example, the structure according to the embodiment can be applied to electric vehicles (EVs), hybrid vehicles (HEVs), plug-in hybrid vehicles (PHEVs), and the like. A plug-in hybrid vehicle is a hybrid vehicle capable of externally charging the battery or externally receiving power from the battery. A plug-in hybrid vehicle is provided with a charging port (inlet) for inserting a charging cable that supplies power from an external charging facility and a power outlet (outlet) for external power supply.

[0018] [I. One Embodiment] In the following one embodiment, a battery pack protective structure for protecting a battery pack mounted on a vehicle will be described. [1. Configuration] Fig. 1 is a perspective view showing an overview of a battery pack protective structure according to an embodiment, showing a battery pack 10 and a vehicle body structure provided around the battery pack 10 from diagonally above on the front left side of the vehicle. Fig. 2 is an exploded perspective view showing the case 12 of the battery pack 10 in Fig. 1 and its surrounding components. Fig. 3 is an exploded perspective view showing the main parts of a structure for reinforcing the battery pack 10. Fig. 4 is a longitudinal cross-sectional view showing the main parts of the battery pack protective structure, a cross-section along the vehicle width direction and the up-down direction as viewed from the front.

[0019] <Basic configuration of battery pack protective structure> As shown in Figures 1 and 2, framework members such as a cross member 20 and a side member 30 are provided around a battery pack 10. The battery pack 10 is a vehicle drive device that houses power storage devices including battery modules 11 (shown by dashed lines in Figure 1) inside a case 12. The battery pack 10 illustrated in Figure 1 has a layout in which four battery modules 11 are arranged side by side in the vehicle width direction.

[0020] The battery module 11 is a secondary battery that can not only supply power but also be charged. The battery module 11 has a larger capacity than on-board batteries such as so-called 12V batteries and 24V batteries. The battery module 11 is a relatively heavy device among the various devices and components housed in the battery pack 10. The case 12 has an opening 14 (see FIG. 2) that is closed by a cover 13 (see FIG. 1). The battery module 11 and other power storage devices are placed inside the case 12 through the opening 14 before the cover 13 is attached to the case 12.

[0021] As shown in FIG. 2 , the case 12 has a bottom surface 15 located below the case 12 and side surfaces 16 located at the transversely oriented ends of the case 12. The bottom surface 15 is a planar portion extending horizontally. The side surfaces 16 are planar portions extending upward from the outer transversely oriented ends of the bottom surface 15, and are provided on the left and right sides. The bottom surface 15 and side surfaces 16 form corners 17 extending in the front-to-rear direction on the transversely oriented end and lower side of the case 12. The corners 17 can be described as linear portions corresponding to fold lines formed by bending one of the bottom surface 15 and the side surfaces 16 toward the other. A cross member 20 having a portion along the corners 17 formed by the bottom surface 15 and the side surfaces 16 will now be described.

[0022] The cross member 20 extends along the vehicle width direction and is a component that forms part of the vehicle body structure. The cross member 20 illustrated in one embodiment is not provided inside the case 12, but is provided only on the outside of the case 12. The cross member 20 is formed along the outer shape of the case 12. Specifically, the cross member 20 has left and right bent portions 2A formed along the left and right corners 17 of the case 12, and inner portions 2B extending inward in the vehicle width direction from each bent portion 2A. The cross member 20 of this embodiment has a vertical cross-sectional shape along the vehicle width direction that is convex downward due to the two bent portions 2A and the inner portion 2B located between them. Because the left and right bent portions 2A are symmetrical, only one of the bent portions 2A will be described.

[0023] The bent portion 2A is located on the outer side or below the corner 17 of the case 12 in the vehicle width direction, and is bent along the corner 17. This bent portion 2A is a linear portion (or a curved surface with a small area) extending in the front-to-rear direction, similar to the corner 17 of the case 12. This bent portion 2A not only plays a part in the vehicle body structure, but also plays a role in protecting the corner 17. For example, when an external force acting inward in the vehicle width direction is applied, the bent portion 2A functions as a protective structure that prevents the side surface 16 forming the corner 17 from deforming so as to collapse inward in the vehicle width direction.

[0024] The inner portion 2B is a portion located below the bottom surface 15 of the case 12 and formed along the bottom surface 15. The inner portion 2B extending below the case 12 in the horizontal direction can be said to be a portion of the cross member 20 that supports the case 12 from below, and can also be said to be a portion that provides a protective structure that protects the bottom surface 15 from below. The cross member 20 in which the inner portion 2B is provided inside the bent portion 2A in the vehicle width direction as described above has a hat-shaped top-bottom cross section (a so-called hat cross section) along the fore-and-aft direction, as shown in Figure 3.

[0025] Specifically, the cross member 20 has a pair of flanges 2C extending to the front and rear, a bottom 2D extending between the pair of flanges 2C and positioned lower than the pair of flanges 2C, and a wall 2E connecting each of the pair of flanges 2C to the bottom 2D. In other words, a recess is defined between the flanges 2C by the bottom 2D and the two wall 2E. Because each wall 2E extends upward from the bottom 2D, it can be said that the wall 2E is a portion that increases the rigidity of the cross member 20 and may also be called a rib.

[0026] 1 and 2 show an example of a structure provided with three (plural) cross members 20. The three cross members 20 are arranged side by side at intervals in the fore-and-aft direction. When it is necessary to distinguish between the three cross members 20, they will be referred to as a first cross member 21, a second cross member 22, and a third cross member 23 in order from front to rear.

[0027] Additionally, a vehicle to which the battery pack protective structure of this embodiment is applied is provided with a pillar (not shown) that serves as a support for the vehicle roof (not shown). The pillar is not provided near the first cross member 21 or the second cross member 22, but is provided near the third cross member 23. When a large external force is applied to the third cross member 23 from the outside in the vehicle width direction, such as during a side collision of the vehicle, part of the external force is distributed to the pillar, and the remainder of the external force (the part other than the part distributed to the pillar) is received by the third cross member 23.

[0028] On the other hand, when a large external force is applied to the first cross member 21 or the second cross member 22 from the outside in the vehicle width direction, such as during a side collision of the vehicle, a portion of the external force is not dispersed to the pillars, and almost all of the external force is received by the first cross member 21 or the second cross member 22. Therefore, it can be said that the first cross member 21 and the second cross member 22 are positioned in areas that require reinforcement more than the third cross member 23.

[0029] The side members 30 are components that extend in the front-to-rear direction on the left and right sides (outside in the vehicle width direction) of the battery pack 10 and form part of the vehicle body structure. The side members 30 are attached across the three cross members 20. The side members 30 illustrated in the one embodiment are not provided inside the case 12, but only on the outside of the case 12.

[0030] 2 and 4 are composed of two members, an upper side member 3U and a lower side member 3L. Specifically, the hollow side member 30 is formed by joining together the upper side member 3U, which has an upwardly convex shape in a longitudinal cross section along the vehicle width direction, and the lower side member 3L, which has a downwardly convex shape. The side member 30 illustrated in FIG. 4 is disposed between the side surface 16 of the case 12 and the cross member 20. Because the side member 30 is interposed between the case 12 and the cross member 20 in this manner, the second angle θ2 formed by the bent portion 2A of the cross member 20 is set to be larger than the first angle θ1 formed by the corner portion 17 of the case 12 when viewed from the front-rear direction.

[0031] The battery pack 10, which is surrounded by the cross members 20 and side members 30, is disposed below a floor panel (not shown). When the battery pack 10 is disposed under the floor of the vehicle (i.e., outside the passenger compartment) in this manner, simply providing the cross members 20 and side members 30 around the battery pack 10 may not be enough to protect the battery pack 10.

[0032] For example, when a large external force is applied from the outside to the inside in the vehicle width direction, such as during a side collision of the vehicle, the bent portion 2A of the cross member 20 may be unable to maintain its shape and may bend inward in the vehicle width direction (hereinafter referred to as ``member collapse deformation''), or the inner portion 2B of the cross member 20 may be unable to maintain its shape and may be distorted into an uneven shape when viewed from the front to rear (hereinafter referred to as ``member distortion deformation'').

[0033] The member collapse deformation may cause the side surface 16 forming the corner 17 to collapse inward in the vehicle width direction (hereinafter referred to as "case collapse deformation"). Furthermore, the member distortion deformation may cause deformation that distorts the bottom surface 15 (hereinafter referred to as "case distortion deformation"). As described above, when the case 12 is deformed by the case collapse deformation due to the member collapse deformation or the case distortion deformation due to the member distortion deformation, the protection of the battery pack 10 is reduced. Therefore, the battery pack protective structure of this embodiment is provided with a reinforcing member that suppresses the member collapse deformation and the member distortion deformation.

[0034] <Detailed Configuration of Battery Pack Protective Structure> The battery pack protective structure of this embodiment is provided with two types of reinforcements 40, 50 as reinforcing members for suppressing deformation, as shown in Figures 3 and 4. The two types of reinforcements 40, 50 are members that reinforce the cross member 20 and are overlapped with at least a portion of the cross member 20. Of the two types of reinforcements 40, 50, one is a first reinforcement 40 that is mainly responsible for reinforcing the bent portion 2A, and the other is a second reinforcement 50 that is mainly responsible for reinforcing the inner portion 2B.

[0035] These two types of reinforcements 40, 50 are both arranged on at least one of the upper and lower sides of the cross member 20. In other words, the first reinforcement 40 and the second reinforcement 50 are arranged side by side on at least the same vertical side of the cross member 20. In this way, the two types of reinforcements 40, 50 that reinforce the cross member 20 from at least one side are provided only on the outside of the case 12, just like the cross member 20 that they are intended to reinforce.

[0036] The two types of reinforcements 40, 50 exemplified in this embodiment are each disposed on both the upper and lower sides of the cross member 20. Specifically, the first reinforcement 40 includes an upper first reinforcement 4U disposed on the upper side of the cross member 20 and a lower first reinforcement 4L disposed on the lower side of the cross member 20. Similarly, the second reinforcement 50 includes an upper second reinforcement 5U disposed on the upper side of the cross member 20 and a lower second reinforcement 5L disposed on the lower side of the cross member 20.

[0037] Hereinafter, when describing a configuration common to the upper first reinforcement 4U and the lower first reinforcement 4L, it will be simply referred to as the first reinforcement 40. Similarly, when describing a configuration common to the upper second reinforcement 5U and the lower second reinforcement 5L, it will be simply referred to as the second reinforcement 50.

[0038] 3 and 4 show an example of an arrangement in which the first reinforcement 40 and the second reinforcement 50 are provided in order from the side closest to the cross member 20. Specifically, from top to bottom, the upper second reinforcement 5U, the upper first reinforcement 4U, the cross member 20, the lower first reinforcement 4L, and the lower second reinforcement 5L are arranged in this order.

[0039] ==First Reinforce== The first reinforcement 40 is a reinforcing member that is superimposed on the cross member 20 along each of the left and right bending portions 2A. That is, the first reinforcement 40 has at least a portion that follows the bending portion 2A. Because the left and right first reinforcements 40 are configured symmetrically, only one of the left and right first reinforcements 40 will be described. This first reinforcement 40 has a first bottom surface portion 41 that extends along the bottom surface 15 of the case 12, and a first side surface portion 42 that extends along the side surface 16. In the first reinforcement 40, the first bottom surface portion 41 and the first side surface portion 42 are integrally formed, and the portion that follows the bending portion 2A is located at the connection point (boundary) between the first bottom surface portion 41 and the first side surface portion 42.

[0040] The first reinforcement 40 can be formed, for example, by bending a single steel plate that has been die-cut based on a development view. The first reinforcement 40 thus formed has a first bottom surface portion 41 along the bottom surface 15 and a first side surface portion 42 along the side surface 16 butted together, resulting in a bent shape similar to the bent portion 2A. The first reinforcement 40 illustrated in FIG. 3 is formed along the bottom portion 2D and each wall portion 2E of the cross member 20. More specifically, the upper first reinforcement 4U is inserted into a recess formed by the bottom portion 2D and each wall portion 2E of the cross member 20. Furthermore, the portions of the upper first reinforcement 4U that face each wall portion 2E (i.e., edges) are positioned so as to abut against each wall portion 2E of the cross member 20.

[0041] In addition, the lower first reinforcement 4L illustrated here has ribs 49 on both the front and rear sides that extend in the vehicle width direction and protrude downward. The ribs 49 extending in the vehicle width direction on both the front and rear sides of the lower first reinforcement 4L can be said to be portions that increase the rigidity of the lower first reinforcement 4L and may also be called protrusions. Note that a welded portion (a so-called bead) that secures the lower first reinforcement 4L to the cross member 20 is provided between the two ribs 49.

[0042] ==Second Reinforce== The second reinforcement 50 is a reinforcing member that is overlapped with at least a portion of the left and right first reinforcements 40 and the inner portion 2B. Because the left and right second reinforcements 50 are configured symmetrically, only one of the left and right second reinforcements 50 will be described. The second reinforcement 50 has a first portion 51 that overlaps with at least a portion of the portion of the first reinforcement 40 that is along the bent portion 2A in a plan view, and a second portion 52 that extends inward in the vehicle width direction from the first portion 51. Note that "at least a portion of the portion that is along the bent portion 2A of the first reinforcement 40" here refers to at least a portion of the portion of the first reinforcement 40 that is along the bent portion 2A of the cross member 20. Because the bent portion 2A is a linear portion extending in the fore-and-aft direction (or a curved surface with a small area), the first portion 51 is also at least a portion of a linear region (or a curved surface with a small area) that extends in the fore-and-aft direction.

[0043] 3 illustrates an example in which the entire upper second reinforcement 5U overlaps with the upper first reinforcement 4U in a plan view, and a portion of the lower second reinforcement 5L overlaps with the entire upper first reinforcement 4U in a plan view. However, a configuration in which a portion of the upper second reinforcement 5U overlaps with the upper first reinforcement 4U in a plan view, and the entire lower second reinforcement 5L overlaps with the upper first reinforcement 4U in a plan view, may also be employed.

[0044] As shown in Fig. 4, the second reinforcement 50 has a second bottom surface portion 53 extending along the bottom surface 15 of the case 12, and a second side surface portion 54 (side surface portion) extending along the side surface 16. In other words, the first portion 51 of the second reinforcement 50 can be described as a linear region (or a curved surface with a small area) corresponding to a fold line formed by folding one of the second bottom surface portion 53 and the second side surface portion 54 toward the other. The second bottom surface portion 53 is a portion extending in a region overlapping with the first bottom surface portion 41 of the first reinforcement 40 in a plan view. The second side surface portion 54 is a portion extending in a region overlapping with the first side surface portion 42 of the first reinforcement 40 in a side view.

[0045] A first bottom surface portion 41 is disposed between the second bottom surface portion 53 and the bottom surface 15 of the case 12, and a first side surface portion 42 is disposed between the second side surface portion 54 and the side surface 16 of the case 12. That is, the first reinforcement 40 is sandwiched between the first portion 51 and a corner portion 17 of the case 12. By extension, at least a portion of the first reinforcement 40 is disposed between at least a portion of the second reinforcement 50 including the first portion 51 and the cross member 20. That is, the first reinforcement 40 and the second reinforcement 50 are disposed in this order from the cross member 20 side.

[0046] As described above, the second portion 52 extends inward in the vehicle width direction from the first portion 51, and therefore extends along the bottom surface 15 of the case 12. This second portion 52 sandwiches at least a portion of the first reinforcement 40 between itself and the bottom surface 15 (see FIG. 3 ) of the case 12, and can also be considered a portion facing the bottom surface 15. This second portion 52 includes a portion (hereinafter also referred to as a "reinforcement wrap region") that overlaps with the battery module 11 (see FIG. 1 ) housed in the case 12 in a planar view. That is, at least a portion of the battery module 11 is disposed above the second portion 52. In other words, the second portion 52 extends from the second bottom surface portion 53 of the first portion 51 downward relative to at least a portion of the battery module 11. Between the second portion 52 and at least a portion of the battery module 11, there is a portion (hereinafter also referred to as a "case wrap region") of the bottom surface 15 of the case 12 where the reinforcement wrap region of the second portion 52 overlaps.

[0047] ==Other== In order to ensure the reinforcement of the cross member 20, it is preferable that all four of the above-mentioned reinforcements 4U, 4L, 5U, and 5L are overlapped on each of the three cross members 21, 22, and 23. However, in order to prevent excessive reinforcement or to reduce weight, for those of the three cross members 21, 22, and 23 that have a relatively high level of strength, some of the reinforcements 4U, 4L, 5U, and 5L may be omitted or made smaller.

[0048] For example, the third cross member 23, which has a pillar nearby, tends to have greater strength than the first cross member 21 and the second cross member 22, which do not have pillars nearby. Therefore, the application of the lower first reinforcement 4L to the third cross member 23 may be omitted, and a lower second reinforcement 5L smaller in size than that applied to the first cross member 21 and the second cross member 22 may be applied.

[0049] In addition, the battery pack protective structure exemplified in this embodiment is provided with a third reinforcement 60 superimposed along the side member 30, as shown in Figures 1 and 4. This third reinforcement 60 is provided only on the outside of the case 12, similar to the side member 30. The third reinforcement 60 is a reinforcing member for the side member 30. The third reinforcement 60 exemplified in Figure 1 is not provided over the entire area in the extension direction of the side member 30 (i.e., the front-to-rear direction), but is provided partially. In the structure exemplified in Figure 1, the third reinforcement 60 is not provided in the area spanning the third cross member 23, but is provided in the area spanning the first cross member 21 and the second cross member 22.

[0050] [2. Actions and Effects] The battery pack protective structure of this embodiment is configured as described above, and therefore provides the following actions and effects. (1) In the battery pack protective structure of this embodiment, the first reinforcement 40 is overlapped with the cross member 20 along the bent portion 2A, and the first portion 51 of the second reinforcement 50 is overlapped with the first reinforcement 40. Therefore, the bent portion 2A of the cross member 20 is reinforced by the first reinforcement 40, and the first reinforcement 40 is reinforced by the first portion 51 of the second reinforcement 50. In other words, the bent portion 2A of the cross member 20 is reinforced by a double structure including not only the first reinforcement 40 but also the first portion 51 of the second reinforcement 50. By reinforcing the bent portion 2A along the corner 17 of the case 12 in this way, the corner 17 of the case 12 can be indirectly reinforced.

[0051] Furthermore, the second portion 52 of the second reinforcement 50 extends into a region overlapping with the inner portion 2B of the cross member 20 in a planar view. Therefore, the inner portion 2B of the cross member 20 is reinforced by the second portion 52 of the second reinforcement 50. By reinforcing the inner portion 2B along the bottom surface 15 of the case 12 in this manner, the bottom surface 15 of the case 12 can be indirectly reinforced. In this manner, the corners 17 and the bottom surface 15 of the case 12, which are more susceptible to deformation than other portions, can be reinforced. For example, in the event of a side collision of the vehicle, the double structure of the first reinforcement 40 and the first portion 51 of the second reinforcement 50 effectively suppresses member collapse and thus suppresses case collapse and deformation. Even if a load that deforms the bottom surface 15 of the case 12 is applied due to the impact of a side collision, the second portion 52 of the second reinforcement 50 suppresses member distortion and suppresses case distortion and deformation. Therefore, protection of the battery pack 10 can be ensured.

[0052] (2) The first portion 51 of the second reinforcement 50 has a second side surface portion 54 that extends along the side surface 16 of the case 12. In this manner, the second side surface portion 54 of not only the first reinforcement 40 but also the second reinforcement 50 extends laterally along the side surface 16 of the case 12, thereby reinforcing the portion of the first reinforcement 40 that is along the side surface 16 of the case 12. From this perspective, it is possible to suppress collapse deformation of the member and collapse deformation of the case.

[0053] (3) At least a portion of the first reinforcement 40 is disposed between at least a portion of the second reinforcement 50, including the first portion 51, and the cross member 20. By arranging the first reinforcement 40 and the second reinforcement 50 in this order from the side closest to the cross member 20, the first reinforcement 40, which reinforces the bent portion 2A, is disposed closer to the bent portion 2A than the second reinforcement 50. Therefore, by reliably reinforcing the bent portion 2A, collapsed deformation of the member and collapsed deformation of the case can be more effectively suppressed. This improves the protection of the battery pack 10.

[0054] (4) The cross member 20 is provided with an upper first reinforcement 4U and an upper second reinforcement 5U on the upper side, and a lower first reinforcement 4L and a lower second reinforcement 5L on the lower side. By providing the first reinforcement 40 and the second reinforcement 50 on both the upper and lower sides of the cross member 20 in this manner, the reinforcing effect of the corners 17 and bottom surface 15 of the case 12 corresponding to the bent portion 2A and inner portion 2B of the cross member 20 is further enhanced. This improves the protection of the battery pack 10.

[0055] (5) The second portion 52 of the second reinforcement 50 includes a portion that overlaps with the battery module 11 housed in the case 12 in a planar view. Therefore, the reinforcement wrap region of the second portion 52 that overlaps with the battery module 11 in a planar view and the case wrap region of the bottom surface 15 where the reinforcement wrap region overlaps are pressed down by the heavy battery module 11. Therefore, the weight of the battery module 11 can be utilized to suppress deformation of the reinforcement wrap region and the case wrap region. This is effective in suppressing deformation of the reinforcement wrap region and the case wrap region when an external force is input from the side of the vehicle, such as during a side collision.

[0056] (6) The side members 30 attached across the three cross members 20 reinforce each cross member 20, contributing to improved protection of the battery pack 10. (7) The third reinforcement 60 overlapped along the side members 30 reinforces the side members 30, contributing to further improved protection of the battery pack 10.

[0057] The third reinforcement 60 exemplified in this embodiment is not provided over the entire area in the extension direction of the side member 30, but is provided partially. Specifically, the third reinforcement 60 is not provided in the area spanning the third cross member 23, but is provided only in the area spanning the first cross member 21 and the second cross member 22. By reinforcing only a portion of the side member 30 with the third reinforcement 60 in this way, it is possible to optimize the reinforcement and suppress an increase in weight.

[0058] (8) A bottom portion 2D and a wall portion 2E extending in the vehicle width direction are provided on both sides of the cross member 20 in the longitudinal direction, and the first reinforcement 40 is formed along the bottom portion 2D and the wall portion 2E. This effectively reinforces the cross member 20. Specifically, the first reinforcement 40 is placed in a recess formed by the bottom portion 2D and the wall portion 2E in the cross member 20, and the portion of the first reinforcement 40 facing the wall portion 2E (the edge, so to speak) is provided so as to abut against the wall portion 2E of the cross member 20. This reliably reinforces the bottom portion 2D and the wall portion 2E (the key portion, so to speak) located in the center of the cross member 20 in the longitudinal direction.

[0059] (9) The lower first reinforcement 4L is provided with ribs 49 on both the front and rear sides, which extend in the vehicle width direction and protrude downward. The ribs 49 extending in the vehicle width direction on both the front and rear sides in this manner increase the rigidity of the lower first reinforcement 4L. This also improves the protection of the battery pack 10. (10) In addition, the cross member 20, side members 30, and reinforcements 40, 50, 60 illustrated in one embodiment are not provided inside the case 12, but only on the outside of the case 12. This allows space to be secured inside the case 12 to accommodate the battery module 11, which contributes to improving layout efficiency within the case 12 and ensuring battery capacity.

[0060] [II. Modifications] The above-described embodiment is merely an example. In the battery pack protective structure, it is sufficient that the first reinforcement and the second reinforcement are provided on at least one of the upper and lower sides of the cross member. For example, the first reinforcement and the second reinforcement may be provided only on the upper or lower side of the cross member. In this way, a battery pack protective structure in which the first reinforcement and the second reinforcement are provided only on one of the upper and lower sides of the cross member can ensure protection of the battery pack with a simple configuration and suppress weight increase.

[0061] The stacking order of the first reinforcement and the second reinforcement is not limited to the first reinforcement, second reinforcement from the side closest to the cross member, but may be the second reinforcement, first reinforcement from the side closest to the cross member. Even with this stacking order, the first reinforcement and second reinforcement can ensure protection of the battery pack. The shape of the cross member is not limited to a hat-shaped cross section having a flange portion, a bottom portion, and a wall portion, and any shape can be used.

[0062] The shape of the reinforcement can be any shape that corresponds to the shape of the object to be reinforced, such as a cross member or a side member. For example, the upper first reinforcement may also be provided with a rib similar to the rib provided on the lower first reinforcement. Alternatively, the first portion of the second reinforcement may be a portion that at least follows the bent portion of the cross member in a plan view, and the second side portion that follows the side of the case may be omitted. Such a second reinforcement can ensure protection of the battery pack with a simple configuration.

[0063] The third reinforcement may be omitted, and furthermore, the side members are not essential components. Furthermore, the second portion of the second reinforcement does not have to overlap with the battery module in a plan view. In other words, the extension range of the second reinforcement can be set to various ranges depending on the area to be reinforced by the second reinforcement.

[0064] This invention can be used in the manufacturing industry of vehicles equipped with battery packs.

[0065] REFERENCE SIGNS LIST 10 Battery pack 12 Case 15 Bottom surface 16 Side surface 17 Corner portion 20 Cross member 2A Bent portion 2B Inner portion 30 Side member 40 First reinforcement 4U Upper first reinforcement 4L Lower first reinforcement 49 Rib 50 Second reinforcement 51 First portion 52 Second portion 54 Second side surface portion (side surface portion) 5U Upper second reinforcement 5L Lower second reinforcement 60 Third reinforcement

Claims

1. A battery pack protective structure comprising: a cross member extending along the vehicle width direction, having a bent portion along a corner formed by the bottom surface of a battery pack case mounted on a vehicle and a side surface located at the vehicle width direction end of the case, and an inner portion extending from the bent portion toward the vehicle width direction inward along the bottom surface; a first reinforcement superimposed on the cross member along the bent portion on at least one of the upper and lower sides of the cross member; and a second reinforcement superimposed on the cross member on at least one of the upper and lower sides of the cross member, having a first portion overlapping at least a portion of the portion of the first reinforcement that follows the bent portion in a planar view, and a second portion extending toward the vehicle width direction inward from the first portion and overlapping at least a portion of the inner portion in a planar view.

2. The battery pack protective structure according to claim 1, characterized in that the first portion has a side portion extending along the side surface.

3. The battery pack protective structure according to claim 1 or 2, characterized in that the first reinforcement and the second reinforcement are arranged in this order from the cross member side.

4. A battery pack protective structure as described in any one of claims 1 to 3, characterized in that the first reinforcement has an upper first reinforcement arranged on the upper side of the cross member and a lower first reinforcement arranged on the lower side of the cross member, and the second reinforcement has an upper second reinforcement arranged on the upper side of the cross member and a lower second reinforcement arranged on the lower side of the cross member.

5. The battery pack protective structure described in any one of claims 1 to 4, characterized in that the second part includes a portion that overlaps with the battery module housed in the case in a plan view.

6. The battery pack protective structure according to any one of claims 1 to 5, characterized in that it comprises a side member that extends in the longitudinal direction of the vehicle along the side surface and is attached across a plurality of the cross members that are arranged side by side at intervals in the longitudinal direction.

7. The battery pack protective structure according to claim 6, characterized in that it comprises a third reinforcement member superimposed along the side member.

8. A battery pack protective structure as described in any one of claims 1 to 7, characterized in that the cross member has a pair of flange portions extending to the front and rear of the vehicle, a bottom portion extending between the pair of flange portions and positioned lower than the pair of flange portions, and a wall portion connecting each of the pair of flange portions and the bottom portion in the vertical direction, and the first reinforcement is formed along the bottom portion and the wall portion.

9. The battery pack protective structure described in any one of claims 1 to 8, wherein the first reinforcement has ribs extending along the vehicle width direction on both the front and rear sides of the vehicle and projecting downward.

10. A battery pack protective structure as claimed in any one of claims 1 to 9, characterized in that the cross member, the first reinforcement and the second reinforcement are provided only on the outside of the case.

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