Protective structure

Abstract

This protective structure is for protecting a battery mounted below the floor of a vehicle and includes a battery module having a plurality of cells. The protective structure further includes: a first lower plate provided facing a lower surface of a battery case of the battery; and a second lower plate provided facing a lower surface of the first lower plate. The first lower plate is formed into a corrugated shape in which a plurality of first convex extension portions, which extend in a first direction and protrude toward the second lower plate side, are arranged along a second direction. The second lower plate extends in the first direction and is formed into a corrugated shape in which a plurality of second convex extension portions, which extend in the first direction and protrude toward the first lower plate side, are arranged along the second direction. A hollow portion is formed between the first lower plate and the second lower plate. A flow path through which flows a fluid capable of adjusting the temperature of the battery is formed between the first convex extension portions and the battery case.

Description

protective structure

[0001] The present disclosure relates to a protective structure for protecting a battery mounted in a vehicle.

[0002] In recent years, automobiles equipped with a motor as a driving source (such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs)) have become widespread. These automobiles (hereinafter collectively referred to as "electric vehicles") are equipped with a battery (hereinafter simply referred to as the battery) for driving the motor. Some such batteries are installed under the floor of the electric vehicle, and techniques for protecting the battery from uneven road surfaces, flying stones, and the like while the vehicle is in motion have been studied (for example, see Patent Document 1).

[0003] Patent Document 1 describes a protective structure for a battery (referred to as a "battery module" in Patent Document 1) mounted under the floor of a vehicle. This battery protective structure includes a case body that houses the battery and a guard member disposed on the lower side of the case body. A gap with a predetermined clearance is provided between the case body and the guard member, and the guard member is configured with a hollow cross-sectional shape.

[0004] Japanese Patent Application Laid-Open No. 2020-183222

[0005] However, the technology described in Patent Document 1 requires the guard member itself to be thick in order to have a hollow structure, which increases the height of the battery. Furthermore, since the battery is mounted under the floor of the vehicle, increasing the height of the battery causes the cabin space to become smaller.

[0006] Therefore, there is a need for a protective structure that can protect the battery without narrowing the vehicle interior.

[0007] A characteristic configuration of the protective structure of the present disclosure is a protective structure for protecting a battery mounted under the floor of a vehicle, comprising a battery module having a plurality of cells, the protective structure comprising: a first lower plate provided opposite the underside of a battery case of the battery; and a second lower plate provided opposite the underside of the first lower plate, wherein the first lower plate is formed in a corrugated shape with first convex extension portions extending along a first direction and protruding toward the second lower plate side, arranged in a plurality of rows along a second direction perpendicular to the first direction, and the second lower plate is formed in a corrugated shape with second convex extension portions extending along the first direction and protruding toward the first lower plate side, arranged in a plurality of rows along the second direction, a hollow portion is formed between the first lower plate and the second lower plate, and a flow path is formed between the first convex extension portions and the battery case through which a fluid capable of regulating the temperature of the battery flows.

[0008] With this characteristic configuration, the hollow portion between the first lower plate and the second lower plate can absorb external impacts and protect the battery. Furthermore, because the hollow portion is formed by the first lower plate and the second lower plate, the protective structure for protecting the battery can be prevented from becoming thick. Furthermore, because a fluid flow path is formed between the first convex extension portion and the battery case, there is no need to provide a separate fluid flow path housing. This simplifies the structure and reduces the thickness compared to when a flow path housing is provided. Therefore, a protective structure that can protect the battery without narrowing the vehicle interior can be realized.

[0009] Fig. 3 is a diagram showing a vehicle equipped with a battery. Fig. 4 is a diagram showing the protective structure as seen from the road surface side. Fig. 5 is a cross-sectional view taken along line III-III in Fig. 2. Fig. 6 is a cross-sectional view of a protective structure of another embodiment. Fig. 7 is a diagram showing a circular recess. Fig. 8 is a diagram showing a case where the battery cover and the first lower plate are joined using a silane coupling agent.

[0010] The protective structure according to the present disclosure is configured to be able to protect a battery mounted under the floor of a vehicle. The protective structure according to the present embodiment will be described below. However, the protective structure is not limited to the following embodiment, and various modifications are possible within the scope of the gist thereof.

[0011] FIG. 1 shows a vehicle 2 equipped with a battery 4 protected by a protective structure. FIG. 2 shows a view of the protective structure from the road surface side. FIG. 3 shows a cross-sectional view taken along line III-III in FIG. 2. In FIGS. 1-3, the direction along the traveling direction of the vehicle 2 is designated as a first direction X, the front side of the traveling direction of the vehicle 2 is designated as "X1," and the rear side of the traveling direction of the vehicle 2 is designated as "X2." Furthermore, the direction intersecting (perpendicular to) the first direction X is designated as a second direction Y, and the direction intersecting (perpendicular to) both the first direction X and the second direction Y is designated as a third direction Z. The second direction Y is the vehicle width direction (left-right direction of the vehicle) of the vehicle 2, and the third direction Z is the vehicle up-down direction.

[0012] The battery 4 stores the power used to run the vehicle 2, and is provided under the floor of the vehicle 2, i.e., in the bottom 2A of the vehicle 2. The battery 4 is covered with a battery cover 4A (corresponding to a "battery case") so as to face the road surface 200. Note that the protective structure is omitted in Figure 2.

[0013] The battery 4 includes a battery module 10 having a plurality of rectangular parallelepiped cells 12 arranged along a first direction X, and the plurality of battery modules 10 are arranged adjacent to each other along a second direction Y.

[0014] The plurality of cells 12 are arranged in parallel and electrically connected to one another. The cells 12 are, for example, lithium-ion batteries. The battery module 10 generates high voltage by connecting the plurality of cells 12 in series. The cells 12 generate heat as they are charged and discharged. If the temperature of the cells 12 increases due to heat generation, the charging and discharging performance of the cells 12 will decrease, so the cells 12 must be cooled. Therefore, this protective structure is configured to protect the battery 4 not only from physical impacts but also from thermal impacts.

[0015] The protective structure is configured to include a first lower plate 50 and a second lower plate 60. The first lower plate 50 is provided opposite the underside of the battery cover 4A of the battery 4. The underside of the battery cover 4A is the surface of the battery cover 4A that covers the battery 4 from the road surface 200 side when it is mounted on the vehicle 2, facing the road surface 200. In other words, the first lower plate 50 is provided opposite the surface of the battery cover 4A that covers the battery 4 from the road surface 200 side when it is mounted on the vehicle 2. Therefore, the first lower plate 50 is provided closer to the road surface 200 than the battery cover 4A.

[0016] The second lower plate 60 is provided opposite the lower surface of the first lower plate 50. The lower surface of the first lower plate 50 is the surface of the first lower plate 50 that faces the road surface 200 and is provided opposite the lower surface of the battery cover 4A. In other words, the second lower plate 60 is provided opposite the surface of the first lower plate 50 that faces the road surface 200 and is provided opposite the battery cover 4A of the battery 4 when mounted on the vehicle 2. Therefore, the second lower plate 60 is provided closer to the road surface 200 than the first lower plate 50.

[0017] As shown in FIG. 3 , the battery cover 4A, the first lower plate 50, and the second lower plate 60 are provided in this order from the battery 4 toward the road surface 200. The first lower plate 50 is formed in a corrugated shape with a plurality of (four in this embodiment) first convex extension portions 51 arranged along the second direction Y, extending along the first direction X and protruding toward the second lower plate 60. "Extending along the first direction X" means that the first lower plate 50 is provided parallel to the longitudinal direction of the vehicle 2. "Protruding toward the second lower plate 60" means that the first lower plate 50 protrudes toward the road surface 200 along the Z direction from a first reference portion 52 along the XY plane of the first lower plate 50 in a cross section along the YZ plane as shown in FIG. 3 . Such protruding portions correspond to the first convex extension portions 51. Therefore, the first lower plate 50 is provided in a state parallel to the front-rear direction of the vehicle 2, and is provided with a first convex extension portion 51 that protrudes in the Z direction toward the road surface 200 from a first reference portion 52 that is along the XY plane on the first lower plate 50. In the present embodiment, as shown in Fig. 3 , the first lower plate 50 is provided with a first reference portion 52A, a first convex extension portion 51A, a first reference portion 52B, a first convex extension portion 51B, a first reference portion 52C, a first convex extension portion 51C, a first reference portion 52D, a first convex extension portion 51D, and a first reference portion 52E in this order along the second direction Y.

[0018] The second lower plate 60 is formed in a corrugated shape with a plurality of (four in this embodiment) second convex extending portions 61 arranged along the second direction Y, extending along the first direction X and protruding toward the first lower plate 50. Protruding toward the first lower plate 50 means that, in a cross section along the YZ plane as shown in FIG. 3 , the second lower plate 60 protrudes from a second reference portion 62 serving as a reference along the Z direction toward the battery 4 along the XY plane of the second lower plate 60. Such protruding portions correspond to the second convex extending portions 61. Therefore, the second lower plate 60 is provided in a state parallel to the front-rear direction of the vehicle 2, and the second convex extending portions 61 are provided along the XY plane of the second lower plate 60, protruding from the second reference portion 62 serving as a reference along the Z direction toward the battery 4. In this embodiment, as shown in Figure 3, the second lower plate 60 is arranged along the second direction Y in the following order: second reference portion 62A, second convex extension portion 61A, second reference portion 62B, second convex extension portion 61B, second reference portion 62C, second convex extension portion 61C, second reference portion 62D, second convex extension portion 61D, and second reference portion 62E.

[0019] Here, in the third direction Z, the battery 4 side is the Z1 side, and the road surface 200 side is the Z2 side. In this embodiment, the first lower plate 50 is provided with the Z1-side surface of the first reference portion 52 abutting against the Z2-side surface of the battery cover 4A. Therefore, the first lower plate 50 is provided with the Z1-side surface of the first reference portion 52A, the Z1-side surface of the first reference portion 52B, the Z1-side surface of the first reference portion 52C, the Z1-side surface of the first reference portion 52D, and the Z1-side surface of the first reference portion 52E abutting against the Z2-side surface of the battery cover 4A, respectively. For this reason, hollow portions are formed between the Z1-side surface of the first convex extension portion 51A, the Z1-side surface of the first convex extension portion 51B, the Z1-side surface of the first convex extension portion 51C, and the Z1-side surface of the first convex extension portion 51D and the Z2-side surface of the battery cover 4A in the first lower plate 50. These hollow portions are used as flow paths 70 through which a fluid capable of regulating the temperature of the battery 4 flows.

[0020] Furthermore, the first convex extension portion 51 is joined to the second lower plate 60, and the second convex extension portion 61 is joined to the first lower plate 50. In this embodiment, the first convex extension portion 51A is joined to the second convex extension portion 61A of the second lower plate 60, the first convex extension portion 51B is joined to the second convex extension portion 61B of the second lower plate 60, the first convex extension portion 51C is joined to the second convex extension portion 61C of the second lower plate 60, and the first convex extension portion 51D is joined to the second convex extension portion 61D of the second lower plate 60. Therefore, the second convex extension portion 61A is joined to the first convex extension portion 51A of the first lower plate 50, the second convex extension portion 61B is joined to the first convex extension portion 51B of the first lower plate 50, the second convex extension portion 61C is joined to the first convex extension portion 51C of the first lower plate 50, and the second convex extension portion 61D is joined to the first convex extension portion 51D of the first lower plate 50.

[0021] As a result, a hollow portion 90 is formed between the first lower plate 50 and the second lower plate 60. That is, the hollow portion 90 is formed by the Z2-side surface of the first reference portion 52 of the first lower plate 50, the Z2-side surface of the first convex extension portion 51 of the first lower plate 50, the Z1-side surface of the second reference portion 62 of the second lower plate 60, and the Z1-side surface of the second convex extension portion 61 of the second lower plate 60.

[0022] Specifically, the Z2-side surface of the first reference portion 52B, the Z2-side surface of the first convex extension portion 51A, the Z2-side surface of the first convex extension portion 51B, the Z1-side surface of the second reference portion 62B, the Z1-side surface of the second convex extension portion 61A, and the Z1-side surface of the second convex extension portion 61B form a hollow portion 90A. Furthermore, the Z2-side surface of the first reference portion 52C, the Z2-side surface of the first convex extension portion 51B, the Z2-side surface of the first convex extension portion 51C, the Z1-side surface of the second reference portion 62C, the Z1-side surface of the second convex extension portion 61B, and the Z1-side surface of the second convex extension portion 61C form a hollow portion 90B. Furthermore, a hollow portion 90C is formed by the Z2 side surface of the first reference portion 52D, the Z2 side surface of the first convex extension portion 51C, the Z2 side surface of the first convex extension portion 51D, the Z1 side surface of the second reference portion 62D, the Z1 side surface of the second convex extension portion 61C, and the Z1 side surface of the second convex extension portion 61D.

[0023] Furthermore, in this embodiment, hollow portions 90D are also formed in the Z2 side surface of the first reference portion 52A, the Z2 side surface of the first convex extension portion 51A, the surface on one side in the second direction Y of the first reference portion 52A on the first lower plate 50 and on the Z2 side, the Z1 side surface of the second reference portion 62A, the Z1 side surface of the second convex extension portion 61A, and the surface on one side in the second direction Y of the second reference portion 62A on the second lower plate 60 and on the Z1 side. In addition, a hollow portion 90E is also formed by the Z2 side surface of the first reference portion 52E, the Z2 side surface of the first convex extension portion 51D, the surface on the other side in the second direction Y of the first reference portion 52E on the first lower plate 50 and on the Z2 side, the Z1 side surface of the second reference portion 62E, the Z1 side surface of the second convex extension portion 61D, and the surface on the other side in the second direction Y of the second reference portion 62E on the second lower plate 60 and on the Z1 side.

[0024] Furthermore, on one side of the hollow portion 90D in the second direction Y and on the other side of the hollow portion 90E in the second direction Y, hollow portions 91, 92 are formed by the Z2 side surface of the battery cover 4A and the Z1 side surface of the first lower plate 50, respectively.

[0025] This prevents damage to the battery 4 from pebbles or other objects that may be kicked up while the vehicle 2 is traveling. Furthermore, because the protective structure has a hollow portion 90, even if an impact is received, it is possible to absorb the impact and protect the battery 4. Furthermore, a double seal is formed by using not only the joining surface where the battery cover 4A and the first reference portion 52 are joined to each other but also the joining surface where the first convex extension portion 51 and the second convex extension portion 61 are joined to each other as a seal for the flow path 70 through which the fluid that can regulate the temperature of the battery 4 flows. Therefore, even if fluid leaks from the flow path 70, it is possible to prevent the fluid from leaking outside the vehicle (to the Z2 side of the second lower plate 60).

[0026] In this embodiment, the first lower plate 50 and the second lower plate 60 are each made of resin. This makes it easier to form them into the above-mentioned shapes, improving workability. Furthermore, because they are made of resin, they can be made lighter.

[0027] Furthermore, in this embodiment, the first lower plate 50 and the second lower plate 60 are each divided into multiple pieces along the second direction Y. This improves molding accuracy, suppresses warping, and facilitates assembly. Note that, in the first direction X, the first lower plate 50 and the second lower plate 60 are configured without being divided from one end side to the other end side.

[0028] Next, the joining of the battery cover 4A and the first lower plate 50 will be described. As described above, the first lower plate 50 is made of resin. On the other hand, the battery cover 4A is made of metal in consideration of the heat transfer and protection of the battery module 10. When the battery cover 4A and the first lower plate 50 are made of different materials, the difference in the linear expansion coefficients of the two plates causes strain, particularly at the joint. Therefore, it is preferable to take measures against shear loads. One such measure is to join the battery cover 4A and the first lower plate 50 using a high-strength joint.

[0029] In this embodiment, the high-strength bonding may be a combination of mechanical bonding and chemical bonding (covalent bonding). That is, it is preferable to perform surface modification in advance on the surface of the battery cover 4A to which the first lower plate 50 is bonded, and then chemically bond the first lower plate 50A to the surface-modified battery cover 4A.

[0030] Specifically, as shown in FIG. 5 , the surface of the battery cover 4A to which the first lower plate 50 is bonded may be modified by forming a circular recess 30 with a diameter A of several nanometers to several millimeters (anchor treatment). By making the circular recess 30 circular in plan view, even when a shear force acts on the circular recess 30, stress concentration does not occur in the circular recess 30, and stress can be evenly distributed along the radial direction of the circular recess 30. Such a circular recess 30 can be formed, for example, by transfer pressing using a transfer press, laser processing in which a material is melted and evaporated by irradiating it with laser light, blasting in which an abrasive is sprayed to change the surface shape, or chemical etching in which a chemical is used as an etchant. This allows the surface of the battery cover 4A to be bonded to the first lower plate 50 to be roughened. The circular recess 30 may be a recess whose diameter A gradually decreases (constricts) as it becomes deeper (closer to the bottom surface).

[0031] The first lower plate 50 is then covalently bonded to the battery cover 4A, which has been subjected to a surface modification treatment. The surface modification treatment is the anchor treatment described above, which corresponds to the treatment for forming the circular recess 30. To covalently bond the first lower plate 50 to the battery cover 4A, a covalent bond promoter is applied to the surface of the battery cover 4A, which has been subjected to the surface modification treatment. The covalent bond promoter is, for example, a silane coupling agent, and has reactive groups that chemically bond with an inorganic material (in this embodiment, the metal constituting the battery cover 4A) and an organic material (in this embodiment, the resin constituting the first lower plate 50). The covalent bond promoter mediates the bond between the metal constituting the battery cover 4A and the resin constituting the first lower plate 50.

[0032] Fig. 6 shows a partially enlarged view of the battery cover 4A and the first lower plate 50 bonded together using a silane coupling agent. As shown in Fig. 6, the silane coupling agent and the first lower plate 50 penetrate the circular recess 30, bond to the inner wall of the circular recess 30, and harden in that state, providing a high-strength bond due to the anchoring effect on the circular recess 30. In addition, the first lower plate 50 is covalently bonded to the silane coupling agent, enabling a high-strength bond between the battery cover 4A and the first lower plate 50.

[0033] Other Embodiments Next, other embodiments of the protective structure will be described.

[0034] In the above embodiment, the flow path 70 through which the fluid capable of regulating the temperature of the battery 4 flows is formed between the first convex extension portion 51 and the battery cover 4A. However, it is also possible to configure the first convex extension portion 51 and the battery cover 4A without allowing the fluid to flow between them. In this case, for example, the fluid may be stored between the first convex extension portion 51 and the battery cover 4A.

[0035] In the above embodiment, in the configuration in which the first convex extension portion 51 is joined to the second lower plate 60 and the second convex extension portion 61 is joined to the first lower plate 50, the first convex extension portion 51A is joined to the second convex extension portion 61A of the second lower plate 60, the first convex extension portion 51B is joined to the second convex extension portion 61B of the second lower plate 60, the first convex extension portion 51C is joined to the second convex extension portion 61C of the second lower plate 60, and the first convex extension portion 51D is joined to the second It has been described that the second convex extension portion 61A is joined to the first convex extension portion 51A of the first lower plate 50, the second convex extension portion 61B is joined to the first convex extension portion 51B of the first lower plate 50, the second convex extension portion 61C is joined to the first convex extension portion 51C of the first lower plate 50, and the second convex extension portion 61D is joined to the first convex extension portion 51D of the first lower plate 50.

[0036] However, in a configuration in which the first convex extension portion 51 is joined to the second lower plate 60 and the second convex extension portion 61 is joined to the first lower plate 50, the first convex extension portion 51A may be spaced apart from the second reference portion 62A of the second lower plate 60, the first convex extension portion 51B may be spaced apart from the second reference portion 62C of the second lower plate 60, the first convex extension portion 51C may be spaced apart from the second reference portion 62D of the second lower plate 60, and the first convex extension portion 51D may be spaced apart from the second reference portion 62E of the second lower plate 60, as shown in Figure 4. In this case, the second convex extension portion 61B is joined to the first reference portion 52B of the first lower plate 50, the second convex extension portion 61C is joined to the first reference portion 52C of the first lower plate 50, and the second convex extension portion 61D is joined to the first reference portion 52D of the first lower plate 50.

[0037] Specifically, the Z2-side surface of the first convex extension portion 51A may be spaced apart from the Z1-side surface of the second reference portion 62A, the Z2-side surface of the first convex extension portion 51B may be spaced apart from the Z1-side surface of the second reference portion 62C, the Z2-side surface of the first convex extension portion 51C may be spaced apart from the Z1-side surface of the second reference portion 62D, and the Z2-side surface of the first convex extension portion 51D may be spaced apart from the Z1-side surface of the second reference portion 62E. Also, the Z1-side surface of the second convex extension portion 61B may be bonded to the Z2-side surface of the first reference portion 52B, the Z1-side surface of the second convex extension portion 61C may be bonded to the Z2-side surface of the first reference portion 52C, and the Z1-side surface of the second convex extension portion 61D may be bonded to the Z2-side surface of the first reference portion 52D. Even in this case, it is possible to form a hollow portion 90 between the first lower plate 50 and the second lower plate 60 .

[0038] 3 and 4, the first lower plate 50 and the second lower plate 60 may be configured with different shapes or may be configured with the same shape. When the first lower plate 50 and the second lower plate 60 are configured with the same shape, the first lower plate 50 can be used as the second lower plate 60 by arranging it so that it is symmetrical with respect to a line parallel to the second direction Y. Therefore, since it is not necessary to provide the first lower plate 50 and the second lower plate 60 separately, the number of types of components required to realize the protective structure can be reduced, and component management costs can be reduced.

[0039] In the above embodiment, the first lower plate 50 and the second lower plate 60 are each described as being made of resin. However, both the first lower plate 50 and the second lower plate 60 may be made of metal. Alternatively, either one of the first lower plate 50 and the second lower plate 60 may be made of metal.

[0040] In the above embodiment, the first lower plate 50 and the second lower plate 60 are each described as being divided into multiple pieces along the second direction Y. However, both the first lower plate 50 and the second lower plate 60 do not have to be divided into multiple pieces along the second direction Y. Furthermore, only one of the first lower plate 50 and the second lower plate 60 may be divided into multiple pieces along the second direction Y.

[0041] In the above embodiment, the first lower plate 50 is described as being bonded to the surface-modified battery cover 4A by a covalent bond. However, the first lower plate 50 may be bonded to the surface-modified battery cover 4A by a hydrogen bond. When using such a hydrogen bond, for example, an adhesive may be used. Note that the bond that contributes to the bond between the first lower plate 50 and the surface-modified battery cover 4A is not limited to a covalent bond or a hydrogen bond, and may be another chemical bond such as an intermolecular force.

[0042] In the above embodiment, a high-strength bond is used to bond the battery cover 4A to the first lower plate 50. However, instead of a high-strength bond, a high-conformity bond can also be used to bond the battery cover 4A to the first lower plate 50. A high-conformity bond uses an adhesive with a relatively high elongation rate. By bonding the battery cover 4A to the first lower plate 50 with such an adhesive, the adhesive can absorb strain caused by a difference in linear expansion coefficients. Therefore, it is preferable to use an adhesive that can absorb strain caused by a difference in linear expansion coefficients between the battery cover 4A and the first lower plate 50.

[0043] Alternatively, an easily dismantled adhesive may be used instead of the adhesive, which can be decomposed by, for example, heat or a chemical. In this case, the battery cover 4A and the first lower plate 50, once joined together, can be easily dismantled.

[0044] In the above embodiment, the first lower plate 50 is made of resin and the battery cover 4A is made of metal. However, the first lower plate 50 may be made of metal. For example, if different types of metals are used for the first lower plate 50 and the battery cover 4A, the joint between the two is a dissimilar material joint.

[0045] [Outline of the above embodiment] The protection structure described above will now be outlined.

[0046] (1) The protective structure includes a battery module 10 having a plurality of cells 12 and protects a battery 4 mounted under the floor of a vehicle 2. The protective structure includes a first lower plate 50 provided opposite the underside of a battery cover 4A (battery case) of the battery 4, and a second lower plate 60 provided opposite the underside of the first lower plate 50. The first lower plate 50 extends along a first direction X and is formed in a corrugated shape with a plurality of first convex extension portions 51 protruding toward the second lower plate 60 arranged along a second direction Y perpendicular to the first direction X. The second lower plate 60 extends along the first direction X and is formed in a corrugated shape with a plurality of second convex extension portions 61 protruding toward the first lower plate 50 arranged along the second direction Y. A hollow portion 90 is formed between the first lower plate 50 and the second lower plate 60. A flow path 70 is formed between the first convex extension portion 51 and the battery cover 4A, through which a fluid capable of regulating the temperature of the battery 4 flows.

[0047] According to this configuration, the hollow portion 90 between the first lower plate 50 and the second lower plate 60 can absorb external impacts and protect the battery 4. Furthermore, because the hollow portion 90 is formed by the first lower plate 50 and the second lower plate 60, the protective structure for protecting the battery 4 can be prevented from becoming thick. Furthermore, because the flow path 70 through which fluid flows is formed between the first convex extension portion 51 and the battery cover 4A, there is no need to provide a separate flow path housing for fluid flow. This simplifies the structure and reduces the thickness compared to when a flow path housing is provided. Therefore, a protective structure that can protect the battery 4 can be realized without narrowing the vehicle interior.

[0048] (2) In the protective structure described in (1), it is preferable that the second convex extension portion 61 is joined to the first convex extension portion 51.

[0049] According to this configuration, the first lower plate 50 and the second lower plate 60 are stacked on top of each other, and the hollow portion 90 can be formed by utilizing the first convex extension portion 51 of the first lower plate 50 and the second convex extension portion 61 of the second lower plate 60. Therefore, the hollow portion 90 can be easily formed. Furthermore, when the flow path 70 is formed using the first convex extension portion 51 as described above, the second lower plate 60 is provided below the first lower plate 50, and a double seal can be provided by the joint between the first lower plate 50 and the battery cover 4A and the joint between the first lower plate 50 and the second lower plate 60. Therefore, even if fluid leaks from the flow path 70, the second lower plate 60 can prevent the fluid from leaking out of the protective structure.

[0050] (3) In the protective structure described in (1), the second convex extension portion 61 may be joined to the first reference portion 52 .

[0051] In this configuration, the first lower plate 50 and the second lower plate 60 are stacked on top of each other, and the hollow portion 90 can be formed by utilizing the first convex extension portion 51 of the first lower plate 50 and the second convex extension portion 61 of the second lower plate 60. Therefore, the hollow portion 90 can be easily formed. Furthermore, when the flow path 70 is formed using the first convex extension portion 51 as described above, the second lower plate 60 is provided below the first lower plate 50, and a double seal can be provided by the joint between the first lower plate 50 and the battery cover 4A and the joint between the first lower plate 50 and the second lower plate 60. Therefore, even if fluid leaks from the flow path 70, the second lower plate 60 can prevent the fluid from leaking out of the protective structure.

[0052] (4) In the protective structure described in any one of (1) to (3), it is preferable that the first lower plate 50 and the second lower plate 60 are each made of resin and divided into multiple pieces along the second direction Y.

[0053] According to this configuration, the first lower plate 50 and the second lower plate 60 can be easily assembled to the battery cover 4A.

[0054] (5) In the protective structure according to any one of (1) to (3), it is preferable that the first lower plate 50 is bonded by a covalent bond to the battery cover 4A that has been subjected to a surface modification treatment.

[0055] According to this configuration, even if there is a difference in the thermal expansion coefficient between the battery cover 4A and the first lower plate 50, it is possible to increase the bonding strength between the battery cover 4A and the first lower plate 50. Therefore, it is possible to improve watertightness and strength.

[0056] The technology according to the present disclosure can be used in a protective structure for protecting a battery mounted in a vehicle.

[0057] 4: Battery, 4A: Battery cover (battery case), 10: Battery module, 12: Cell, 50: First lower plate, 51: First convex extension, 52: First reference portion, 60: Second lower plate, 61: Second convex extension, 70: Flow path, 90: Hollow portion, X: First direction, Y: Second direction

Claims

1. A protective structure for protecting a battery mounted under the floor of a vehicle, the protective structure comprising: a battery module having a plurality of cells; a first lower plate provided opposite the underside of a battery case of the battery; and a second lower plate provided opposite the underside of the first lower plate; the first lower plate is formed in a corrugated shape, with first convex extension portions extending along a first direction and protruding toward the second lower plate, arranged in a plurality of rows along a second direction perpendicular to the first direction; the second lower plate is formed in a corrugated shape, with second convex extension portions extending along the first direction and protruding toward the first lower plate, arranged in a plurality of rows along the second direction; a hollow portion is formed between the first lower plate and the second lower plate; and a flow path through which a fluid capable of regulating the temperature of the battery flows is formed between the first convex extension portions and the battery case.

2. The protective structure according to claim 1, wherein the second convex extension is joined to the first convex extension.

3. The protective structure according to claim 1, wherein the second protruding extension is joined to the first reference portion.

4. A protective structure according to any one of claims 1 to 3, wherein the first lower plate and the second lower plate are each made of resin and divided into multiple pieces along the second direction.

5. A protective structure according to any one of claims 1 to 3, wherein the first lower plate is covalently bonded to the battery case, which has been subjected to a surface modification treatment.

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