Vehicle body side structure

Abstract

A vehicle body side structure (1) is provided with a side sill (3) extending in the vehicle length direction, and a battery pack (5) disposed further toward the vehicle width direction inner side than the side sill (3), the vehicle width direction outer peripheral side of the battery pack (5) is provided with a collision energy absorbing member (11) provided in a convex shape toward the vehicle width direction outer side, and the collision energy absorbing member (11) is provided in a convex shape toward the vehicle width direction outer side. The collision energy absorbing member (11) is made of a steel plate having a tensile strength of 270-340 MPa and a plate thickness of 1.0-1.4 mm, and when a collision load is input from the outside in the vehicle width direction to the side surface of the side sill (3), the collision energy absorbing member (11) is deformed and absorbs collision energy after the side sill (3) deformed by the input collision load comes into contact with the collision energy absorbing member (11). Therefore, the load transmitted to the battery pack (5) is reduced.

Description

Technical Field

[0001] The present invention relates to an automotive body side structure of an electric vehicle or the like in which a battery pack is disposed on the vehicle inner side in the vehicle width direction relative to a side sill. Background Art

[0002] In recent years, especially in the automobile industry, due to environmental issues, the replacement from gas-engine cars to electric cars is being promoted. Electric cars and the like are equipped with a battery pack that accommodates a large battery in the floor portion of the lower part of the vehicle body. Moreover, most of these batteries use lithium-based materials, so if the battery pack is damaged and liquid leaks from the battery during a collision, there is a risk of fire, so a structure to protect the battery pack is required. As a structure to protect the battery pack, there are lower longitudinal beams on both outer sides in the vehicle width direction, and the battery pack is arranged between the lower longitudinal beams.

[0003] As a technology for protecting the battery pack, for example, the following technology is disclosed in Patent Document 1: In a vehicle having a locker (lower longitudinal beam) with a closed cross section, and a battery pack fixed to the locker in a state of being supported from the bottom, a ladder-shaped impact absorption part formed of aluminum alloy or the like and having a closed cross section structure is provided in the locker. Moreover, according to this technology, the impact absorption part undergoes plastic deformation during a side impact collision of the vehicle, thereby absorbing the collision energy, and thus it is believed that the battery pack can be protected.

[0004] In addition, Patent Document 2 discloses a technology in which a battery pack is detachably fixed to a floor side member and suspended from a floor panel. According to this technology, the battery pack is released from the side impact collision of the vehicle body and is supported only on the floor panel, which is believed to be able to properly protect the battery pack.

[0005] Patent Document 1: Japanese Patent No. 6930267

[0006] Patent Document 2: Japanese Patent Application Publication No. 2019-167060

[0007] As a structure to protect the battery pack, it is important to arrange impact energy absorbing parts (parts for impact energy absorption) around the battery pack to absorb collision energy. However, in the technology disclosed in Patent Document 1, the closed cross-sectional structure of the impact absorbing part (collision energy absorbing part) formed in the lower side beam (lower longitudinal beam) is very complicated, and the weight becomes heavier, and there is a concern that it will have an adverse effect on fuel consumption. In addition, it is difficult to manufacture at a low price when using aluminum alloy. In addition, since the closed cross-sectional structure of the impact absorbing part is strong, the load is excessively transferred to the battery pack (battery pack) during the deformation of the lower side beam (lower longitudinal beam) during a side collision, thereby there is a possibility of damage to the battery pack.

[0008] In addition, in the technology disclosed in Patent Document 2, the battery pack is detached from the floor longitudinal beam and supported only by the floor panel in the event of a side collision of the vehicle. Therefore, in addition to the possibility of the battery pack falling off and being damaged, if the mechanism for releasing the fixed state does not work, there is a concern that the collision load (crushing load) will be input to the battery pack through the deformed lower longitudinal beam and damage it. Therefore, in a vehicle having a lower longitudinal beam and a battery pack arranged on the inner side of the lower longitudinal beam in the vehicle width direction, a structure is required to efficiently and reliably absorb the collision energy to protect the battery pack in the event of a side collision. Summary of the invention

[0009] The present invention has been made to solve the above-mentioned problems, and its object is to provide a vehicle body side structure that can efficiently and reliably absorb collision energy and protect the battery pack when a vehicle body including a side sill and a battery pack arranged on the vehicle width direction inner side of the side sill is subjected to a side collision.

[0010] The vehicle body side structure of the present invention comprises a lower longitudinal beam extending in the vehicle length direction, and a battery pack arranged on the vehicle inner side in the vehicle width direction relative to the lower longitudinal beam, wherein the collision energy absorbing member comprises a substantially U-shaped cross section, the substantially U-shaped cross section having a bottom portion substantially parallel to the vehicle height direction, and a pair of longitudinal wall portions (side wall portions) continuous from the upper end and the lower end of the bottom portion, the collision energy absorbing member ensures a space between the lower longitudinal beam and the vehicle outer side in the vehicle width direction of the battery pack, and is provided in a convex shape toward the vehicle outer side in the vehicle width direction, the collision energy absorbing member is made of a steel plate having a tensile strength of 270 MPa-class or more and 340 MPa-class or less and a plate thickness of 1.0 mm or more and 1.4 mm or less. When a collision load is input to the lower longitudinal beam from the outer side of the vehicle in the vehicle width direction, the lower longitudinal beam deformed by the input collision load contacts the collision energy absorbing component, and the collision energy absorbing component deforms to absorb the collision energy, thereby reducing the load transmitted to the battery pack.

[0011] The collision energy absorbing member may be configured such that an aspect ratio of the height in the vehicle height direction to the width in the vehicle width direction is within a range of 0.4 to 2.5.

[0012] The collision energy absorbing member may be configured such that the pair of vertical wall portions are inclined in a direction approaching each other toward the outer side of the vehicle in the vehicle width direction.

[0013] The collision energy absorbing member may be configured such that one of the longitudinal wall portions is parallel to a horizontal line in the vehicle width direction, and the other longitudinal wall portion is inclined toward the vehicle outer side in the vehicle width direction toward the one longitudinal wall portion.

[0014] According to the present invention, when a vehicle with a battery pack disposed on the vehicle's inner side in the vehicle width direction is subjected to a side collision, the collision load input to the vehicle can be prevented from being easily transmitted to the battery pack. As a result, the deformation of the battery pack can be suppressed during a side collision, the battery pack of an electric vehicle or the like can be protected, and a safe vehicle can be manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The following are diagrams for explaining the vehicle body side structure according to the embodiment of the present invention.

[0016] Figure 2 These are diagrams for explaining specific examples of the shape of a collision energy absorbing member in the vehicle body side structure according to the embodiment of the present invention.

[0017] Figure 3 This is a diagram for explaining a side collision of a vehicle that is an analysis target in the embodiment.

[0018] Figure 4 The figures show the evaluation method of the deformation amount of the battery pack and the input load to the battery pack in the examples ((a) evaluation position of the deformation amount of the battery pack, (b) input load to the battery pack).

[0019] Figure 5 The figures show the vehicle body side structures of Invention Examples 1 to 3 in the embodiments ((a) Invention Example 1, (b) Invention Example 2, (c) Invention Example 3).

[0020] Figure 6 The figures show the vehicle body side structures of Inventive Example 4 and Inventive Example 5 and the conventional example in the embodiment ((a) Inventive Example 4, (b) Inventive Example 5, (c) Conventional Example).

[0021] Figure 7 This is a graph showing the results of contact reaction force obtained as input load to the battery pack in the examples.

[0022] Figure 8 This is a graph showing the maximum values ​​of the contact reaction forces obtained as the input load to the battery pack in the case where the aspect ratio of the collision energy absorbing member is changed in the embodiment.

[0023] Fig. 9 The figures show the deformation states of the vehicle body side structures of Invention Examples 1 to 5 and the prior art example during a side collision in the embodiments ((a) Invention Example 1, (b) Invention Example 2, (c) Invention Example 3, (d) Invention Example 4, (e) Invention Example 5, (f) Prior art example).

[0024] Fig.10 This is a graph showing the deformation amount and contact reaction force of the battery pack when the tensile strength and plate thickness of the steel plate used for the collision energy absorbing member of the vehicle body side structure of the inventive example are changed in the embodiment. DETAILED DESCRIPTION

[0025] As an example, the vehicle body side structure 1 according to the embodiment of the present invention is Figure 1 As shown, the vehicle body side structure 1 includes: a lower longitudinal beam 3 extending in the vehicle length direction; a battery pack 5 arranged on the vehicle width inner side of the lower longitudinal beam 3; a floor cross member 7; and a ground side cross member 9. In addition, the vehicle body side structure 1 of the embodiment of the present invention has a collision energy absorbing component 11 on the outer peripheral side of the battery pack 5 in the vehicle width direction. Figure 1 A vehicle body side structure 1 according to the present embodiment will be described. In the present specification and the drawings, elements having the same functional configuration are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0026] like Figure 1 As shown, the side sill 3 includes: a side sill inner 3a having a groove shape opening toward the vehicle outer side in the vehicle width direction; and a side sill outer 3b having a groove shape opening toward the vehicle inner side in the vehicle width direction. In addition, the side sill inner 3a and the side sill outer 3b make their opening sides face each other and join the end on the upper side of the vehicle body and the end on the lower side of the vehicle body respectively to form a closed cross section structure. In addition, the groove shape of the side sill inner 3a is formed into a cross section hat-shaped by a bottom 3a1 substantially parallel to the vehicle height direction and a pair of longitudinal wall portions 3a2 and 3a3 respectively continuous from the upper end and the lower end of the bottom 3a1.

[0027] The battery pack 5 has a battery cell (not shown) mounted therein and includes a battery pack upper part 5a and a battery pack lower part 5b. The battery pack 5 is supported by a battery frame assembly 13 disposed on the outer peripheral side in the vehicle width direction. Figure 1 As shown, the battery frame assembly 13 is composed of a plurality of steel sheet parts.

[0028] The floor cross member 7 is disposed on the upper side of the vehicle body of the battery pack 5 , and an end portion 7 a on the outer side in the vehicle width direction is connected to an upper portion of the side sill inner member 3 a .

[0029] The ground-side cross member 9 is disposed on the vehicle body lower side of the battery pack 5 , and an end portion 9 a on the vehicle outer side in the vehicle width direction is fastened to the lower portion of the side member 3 by a bolt 15 .

[0030] The collision energy absorbing member 11 has a substantially U-shaped cross-section 11d having a bottom 11a substantially parallel to the vehicle height direction, and a pair of longitudinal wall portions 11b and 11c that are continuous from the upper end and the lower end of the bottom 11a and substantially parallel to the vehicle width direction. In addition, the collision energy absorbing member 11 is provided in a convex shape toward the vehicle outer side in the vehicle width direction, with a space being ensured between the lower longitudinal beam 3 and the battery frame assembly 13 on the outer peripheral side of the battery pack 5 in the vehicle width direction. Moreover, the collision energy absorbing member 11 is made of a steel plate having a tensile strength of 270 MPa or more and 340 MPa or less and a plate thickness of 1.0 mm or more and 1.4 mm or less. In the present embodiment, the collision energy absorbing member 11 is joined to the outer peripheral surface of the battery frame assembly 13 along the entire length of the battery frame assembly 13 in the vehicle length direction or is joined to the outer peripheral surface of the battery frame assembly 13 in a portion of the vehicle length direction. The range of the tensile strength and plate thickness of the steel plate used for the collision energy absorbing member 11 will be described in the embodiment described later.

[0031] Moreover, in the vehicle body side structure 1, when a side collision occurs in which a collision load is input to the lower longitudinal beam 3 from the outer side of the vehicle in the vehicle width direction, after the lower longitudinal beam 3 deformed by the input collision load contacts the collision energy absorbing component 11, the collision energy absorbing component 11 deforms and absorbs the collision energy, thereby reducing the load transmitted to the battery pack 5.

[0032] The impact absorbing portion (equivalent to the collision energy absorbing member of the present application) in the technology disclosed in Patent Document 1 absorbs collision energy while deforming when the vehicle collides sideways. However, as mentioned above, since the closed cross-section structure of the impact absorbing portion is strong, the impact load is transmitted to the battery pack on the inner side of the vehicle in the vehicle width direction during the deformation of the impact absorbing portion, and there is a concern that the battery pack may be damaged.

[0033] In contrast, the vehicle body side structure 1 according to the present embodiment is formed into a cross-sectional structure that allows the collision energy absorbing component 11 to be easily deformed, and is composed of a thin steel plate having a low strength of 270 MPa to 340 MPa and a plate thickness of 1.0 mm to 1.4 mm. As a result, when a side collision occurs on a vehicle in which a battery pack 5 is arranged on the vehicle inner side of the lower longitudinal sill 3 in the vehicle width direction, after the deformed lower longitudinal sill 3 contacts the collision energy absorbing component 11, the collision energy absorbing component 11 deforms to absorb the collision energy. Therefore, it is possible to make it difficult for the collision load input to the vehicle to be transmitted to the battery pack 5. As a result, the transmission load during a side collision can be reduced and the deformation of the battery pack 5 can be suppressed, thereby protecting the battery pack 5 of the electric vehicle and manufacturing a safe vehicle.

[0034] In the vehicle body side structure 1, the collision energy absorbing member 11 is set so that the aspect ratio (W / H) of the width W in the vehicle width direction relative to the height H in the vehicle height direction is within the range of 0.4 to 2.5. Figure 2 The vehicle body side structure 1 shown in (a) and (b) is that the height H of the collision energy absorbing member 11 in the vehicle height direction is not changed, and the width W in the vehicle width direction is set so that the aspect ratio W / H is within the range of 0.4 to 2.5 ( Figure 2 (a): W / H = 0.86, Figure 2 A specific example in which the setting is performed as (b): W / H=1.43).

[0035] Thus, the collision energy absorbing member 11 can be provided between the side sill 3 and the battery pack 5 , and the collision energy can be sufficiently absorbed by the collision energy absorbing member 11 during a side collision.

[0036] In the above description, if Figure 2 As shown in (a) and (b) of FIG. 1 , the pair of vertical wall portions 11b and 11c of the collision energy absorbing member 11 are both horizontal in the vehicle width direction.

[0037] However, in the present invention, if Figure 2 As shown in (c) of the collision energy absorbing member 23, it is preferred to have a substantially U-shaped cross-section portion 23d, the substantially U-shaped cross-section portion 23d having a bottom portion 23a substantially parallel to the vehicle height direction, and a pair of longitudinal wall portions 23b, 23c continuous from the upper end and the lower end of the bottom portion 23a, the pair of longitudinal wall portions 23b, 23c being inclined in a direction approaching the outer side of the vehicle in the vehicle width direction. In particular, it is preferred that the inclination angles of the longitudinal wall portions 23b, 23c are both 20° or less relative to the horizontal line in the vehicle width direction. The inclination angle of the longitudinal wall portion is set to an angle on the acute angle side relative to the horizontal line (the same applies below).

[0038] Or, if Figure 2 As shown in FIG. 2 (d), the collision energy absorbing member 27 preferably includes a substantially U-shaped cross-section portion 27d, the substantially U-shaped cross-section portion 27d having a bottom portion 27a substantially parallel to the vehicle height direction and a pair of longitudinal wall portions 27b and 27c continuous from the upper end and the lower end of the bottom portion 27a, one longitudinal wall portion 27b being parallel to the horizontal line in the vehicle width direction, and the other longitudinal wall portion 27c being inclined toward the vehicle outer side in the vehicle width direction toward the longitudinal wall portion 27b. In particular, it is preferred that the inclination angle of the inclined longitudinal wall portion 27c relative to the horizontal line in the vehicle width direction is 20° or less.

[0039] In this way, by making both the pair of longitudinal wall portions 23b and 23c of the collision energy absorbing member 23 or the longitudinal wall portion 27c of the collision energy absorbing member 27 inclined relative to the horizontal line in the vehicle width direction, the collision energy absorbing member has an inclined longitudinal wall portion, thereby forming a shape in which the cross section expands as the deformation progresses, and is easily crushed at the initial stage of contact, and can be deformed greatly at the later stage of contact. Therefore, the load transmitted to the battery pack during a side collision can be further reduced.

[0040] In addition, the reason why the inclined angle of the inclined longitudinal wall portion 23b, 23c, or the longitudinal wall portion 27c has an upper limit of 20° is that if the inclined angle is greater than 20°, it is difficult to be crushed, or buckling occurs during plastic deformation and cannot be completely crushed. In contrast, when the inclined angle of the inclined longitudinal wall portion 23b, 23c, or the longitudinal wall portion 27c is less than 20°, the longitudinal wall portion 23b, 23c, or the longitudinal wall portion 27b can be easily crushed, which is preferable in terms of absorbing collision energy.

[0041] like Figure 1 As shown, the vehicle body side structure 1 of the present embodiment includes a battery frame assembly 13, and the collision energy absorbing member 11 is provided on the outer peripheral surface in the vehicle width direction of the battery frame assembly 13. However, the vehicle body side structure of the present invention may not include a battery frame assembly, in which case the collision energy absorbing member only needs to be provided on the outer peripheral surface of the battery pack in the vehicle width direction.

[0042] In addition, the vehicle body side structure 1 of the present embodiment is provided with a floor cross member 7 on the upper side of the battery pack 5 and a ground side cross member 9 on the lower side, but the present invention may also be provided with only the floor cross member 7. In this case, after the lower longitudinal member is deformed and contacts the collision energy absorbing member, the collision energy absorbing member deforms to absorb the collision energy, thereby reducing the load transmitted to the battery pack and suppressing the deformation of the battery pack.

[0043] In the present embodiment, as described above, the collision energy absorbing member 11 ensures a predetermined space between the collision energy absorbing member 11 and the side sill 3, and is provided on the battery pack 5 side. Furthermore, in order to reliably ensure a space between the collision energy absorbing member 11 and the side sill 3, it is preferable to set the width W of the collision energy absorbing member 11 so that the bottom 11a of the collision energy absorbing member 11 is located closer to the vehicle inward in the vehicle width direction than the innermost position on the vehicle inward side of the side sill 3 (the vehicle width direction position of the bottom 3a1 of the side sill inner member 3a).

[0044] Example

[0045] Since a specific analysis was performed to verify the effects of the vehicle body side structure of the present invention, the results will be described below.

[0046] In this embodiment, if Figure 3 As shown, a side collision analysis was performed on a vehicle 101 having a vehicle body side structure 1 (invention example) in which a pole 103 collides with the vehicle from the outside in the vehicle width direction. The vehicle body side structure 1 has the Figure 1 The lower side sill 3 , the battery pack 5 , the floor cross member 7 and the ground side cross member 9 are shown, and have a collision energy absorbing component 11 .

[0047] In the side collision analysis, the vehicle 101 is accelerated to 29 km / h in the vehicle width direction, and the rod 103 as a rigid body is made to collide with the side of the vehicle 101. The rod collision position where the rod 103 collides with the vehicle 101 is set at two levels of vehicle length direction position TL=1394 mm and 1916 mm. TL=1916 mm is where the floor cross member 7 and the ground side cross member 9 ( Figure 1 ) in the vehicle length direction, TL=1394 mm is the vehicle length direction position where the floor cross member 7 and the ground side cross member 9 are not configured.

[0048] When the rod 103 collides with the side sill 3 of the side of the vehicle 101, the side sill 3 (see Figure 1 ) is locally deformed and intrudes into the vehicle interior. Therefore, in this embodiment, the deformation amount of the battery pack 5 and the load input to the battery pack 5 during the side collision are evaluated.

[0049] Regarding the deformation amount of the battery pack 5, Figure 4 As shown in (a), at multiple positions in the vehicle length direction (in Figure 4 The lengths of the battery pack 5 in the vehicle width direction before and after deformation were measured at the position indicated by the arrow in (a), and the difference between before and after deformation was obtained. On the other hand, regarding the load input to the battery pack 5 side, as shown in FIG. Figure 4 As shown in (b), the reaction force (contact reaction force) generated in the battery frame assembly 13 due to the contact between the collision energy absorbing member 11 and the side sill inner member 3a during the collision is obtained.

[0050] In this embodiment, if Figure 5 and Figure 6 As shown, the cases where the sizes and shapes of the collision energy absorbing members 11 , 23 , 27 are changed within the scope of the present invention are referred to as Invention Examples 1 to 5.

[0051] like Figure 5 As shown in (a) of the first embodiment of the invention, the vertical wall portions 11b and 11c of the collision energy absorbing member 11 are both horizontal in the vehicle width direction, and are set to have a width W of 50 mm and a height H of 35 mm.

[0052] like Figure 5As shown in (b), Example 2 of the invention is constructed such that the longitudinal wall portions 23b and 23c of the collision energy absorbing component 23 are inclined toward the outer side of the vehicle in the vehicle width direction relative to the horizontal line in the vehicle width direction, so that the height at the innermost position is maintained equal to the height of Example 1 of the invention (=35mm), and the height at the outermost position in the vehicle width direction is 25mm.

[0053] like Figure 5 As shown in (c), in the third embodiment of the present invention, the width W of the collision energy absorbing member 11 is smaller than that of the first embodiment of the present invention and is 40 mm.

[0054] like Figure 6 As shown in (a) of the drawings, the fourth invention example is configured such that the width W of the collision energy absorbing member 11 is further reduced compared with the third invention example and is 30 mm.

[0055] like Figure 6 As shown in (b), Example 5 of the invention is constructed such that the longitudinal wall portion 27b of one side of the collision energy absorbing component 27 is parallel to the horizontal line in the vehicle width direction, and the longitudinal wall portion 27c of the other side is inclined relative to the horizontal line in the vehicle width direction toward the outer side of the vehicle in the vehicle width direction toward the longitudinal wall portion 27b of one side, so that the height at the innermost position is 10mm larger than the height of Example 1 of the invention (=35mm).

[0056] In addition, in this embodiment, as a comparison object, Figure 6 The vehicle body side structure 21 (conventional example) shown in (c) and the vehicle body side structure 1 (Comparative Examples 1 to 6) in which the tensile strength and the plate thickness of the steel plate used for the collision energy absorbing member 11 are outside the preferred range of the present invention as shown in Table 1 are also carried out in the same manner as the inventive examples (inventive examples 1 to 5). Figure 3 The side collision analysis of the vehicle 101 shown evaluates the deformation of the battery pack 5 during the side collision and the load input to the battery pack 5. The height H in Table 1 describes the height of the vehicle outside in the vehicle width direction.

[0057] [Table 1]

[0058]

[0059] like Figure 6 As shown in (c) , the vehicle body side structure 31 of the conventional example includes a side sill 3 having a side sill inner member 3a and a side sill outer member 3b , and the lower portion of the side sill 3 is connected to the battery frame assembly 13 via an aluminum connecting member 33 .

[0060] The deformation amount of the battery pack 5 in the conventional example was obtained in the same manner as in the inventive example (see Figure 4). In addition, for the load input to the battery pack 5 side in the conventional example, the contact reaction force between the connecting member 33 and the battery frame assembly 13 was obtained.

[0061] Comparative Example 1 maintains the same width W (=50 mm) as that of the collision energy absorbing member 11 of Inventive Example 1, reduces the height H to 15 mm, and makes the aspect ratio W / H larger than the range of the present invention (0.4 or more and 2.5 or less) (=3.33). Comparative Example 2 maintains the same height H (=35 mm) as that of the collision energy absorbing member 11 of Inventive Example 1, reduces the width W to 10 mm, and makes the aspect ratio W / H smaller than the range of the present invention (0.4 or more and 2.5 or less) (=0.29). Comparative Example 3 changes both the height H and the width W of the collision energy absorbing member 11, and makes the aspect ratio W / H smaller than the range of the present invention (0.4 or more and 2.5 or less) (=0.33). Comparative Example 4 changes both the height H and the width W of the collision energy absorbing member 11, and makes the aspect ratio W / H larger than the range of the present invention (0.4 or more and 2.5 or less) (=2.67). Comparative Example 5 maintains the same height H (=35 mm) as that of the collision energy absorbing member 11 of Inventive Example 1, increases the width W to 100 mm, and makes the aspect ratio W / H larger (=2.86) than the range of the present invention (0.4 or more and 2.5 or less). Comparative Example 6 changes both the height H and the width W of the collision energy absorbing member 11, and makes the aspect ratio W / H smaller (=0.30) than the range of the present invention (0.4 or more and 2.5 or less).

[0062] Figure 7 In the invention examples 1 to 5 and the conventional example, the pole collision position is set to the vehicle length direction position TL=1394 mm ( Figure 7 (a)) and 1916mm( Figure 7 The result of the contact reaction force obtained as the load input to the battery pack 5 during the side collision of (b)). Figure 7 As shown, it can be seen that the contact reaction force of Inventive Examples 1 to 5 is significantly reduced compared to the conventional example regardless of the rod collision position.

[0063] Figure 8 The graph shows the relationship between the maximum value of the contact reaction force obtained as the load input to the battery pack 5 during the side collision of the vehicle 101 and the aspect ratio W / H of the collision energy absorbing member 11 when the aspect ratio W / H of the collision energy absorbing member 11 is changed. In addition, the maximum values ​​of the contact reaction forces obtained for the inventive examples 1 to 5 and the comparative examples 1 to 6 are shown in the above-mentioned Table 1.

[0064] like Figure 8As shown in Table 1, when the aspect ratio W / H of the collision energy absorbing component 11 is outside the scope of the present invention, that is, less than 0.4 or greater than 2.5, the maximum value of the contact reaction force is greater than 100 kN, but when the aspect ratio W / H is within the scope of the present invention, greater than 0.4 and less than 2.5, the maximum value of the contact reaction force is less than 100 kN.

[0065] Fig. 9 The following diagram shows the deformation of the rod 103 after the collision when the rod 103 collides sideways with the vehicle 101 including the vehicle body side structures 1, 21, 25, and 31 of Inventive Examples 1 to 5 and the conventional example.

[0066] In the existing example ( Fig. 9 In (f)), the connecting member 33 connecting the lower side beam 3 and the battery frame assembly 13 is not sufficiently deformed to the extent of being completely crushed, and the load input to the vehicle 101 is transmitted to the battery pack 5 side, causing the battery pack 5 to deform.

[0067] In contrast, in the vehicle body side structures 1, 21, and 25 of the invention examples 1 to 5, the collision energy absorbing members 11, 23, and 27 are fully deformed and completely crushed. Therefore, it can be seen that in the invention examples 1 to 5, after the side sill 3 is deformed and contacts the collision energy absorbing member 11, the collision energy is further absorbed, thereby reducing the load transmitted to the battery pack 5 and protecting the battery pack 5.

[0068] Fig.10 The results of the time variation of the deformation amount and contact reaction force of the battery pack 5 during the side collision of the vehicle 101 are shown when the tensile strength and thickness of the steel plate used in the collision energy absorbing member 11 are changed. The floor cross member 7 and the ground side cross member 9 are arranged at the positions TL=1230mm, 1569mm, 1916mm, and 2243mm in the vehicle length direction. Figure 1 )( Fig.10 A) in Fig.10 These are the results obtained when the vehicle length direction position TL=1394 mm, that is, the position where the floor cross member 7 and the ground-side cross member 9 are not arranged, is regarded as the pole collision position.

[0069] Regarding the deformation amount of the battery pack 5, Fig.10 As shown in (a), the results shown in the invention example and the comparative example are lower than those in the prior art example regardless of the tensile strength and plate thickness. However, the deformation of the battery pack of the invention example with a thinner plate thickness is smaller than that of the comparative example. In addition, the deformation of the battery pack is almost unchanged when the plate thickness is equal but the tensile strength is different, and the influence of the tensile strength is very slight.

[0070] In addition, regarding the contact reaction force, Fig.10As shown in (b), the results shown in the invention example and the comparative example are lower than those in the prior art example regardless of the tensile strength and plate thickness. However, the contact reaction force of the invention example with a thinner plate thickness is reduced compared to the comparative example. In addition, the contact reaction force is almost unchanged when the plate thickness is equal but the tensile strength is different, and the influence of the tensile strength is very slight.

[0071] Moreover, according to Fig.10 The results shown indicate that the collision energy absorbing component 11 is able to absorb the collision energy by easily deforming during a side collision by setting the tensile strength of the steel plate to between 270 MPa and 340 MPa and the plate thickness to less than 2 mm, specifically, to less than 1.4 mm, thereby enabling the collision energy absorbing component 11 to be sufficiently reduced in terms of input load to the battery pack 5 by absorbing the collision energy during a side collision.

[0072] Industrial Applicability

[0073] According to the present invention, a vehicle body side structure can be provided that can efficiently and reliably absorb collision energy and protect the battery pack when a vehicle body including a side sill and a battery pack disposed on the vehicle widthwise inner side of the side sill collides with a side surface.

[0074] Description of Reference Numerals

[0075] 1…body side structure; 3…lower longitudinal beam; 3a…lower longitudinal beam inner member; 3a1…bottom; 3a2…longitudinal wall; 3a3…longitudinal wall; 3b…lower longitudinal beam outer member; 5…battery pack; 5a…battery pack upper member; 5b…battery pack lower member; 7…floor cross beam; 7a…end; 9…ground side cross beam; 9a…end; 11…collision energy absorbing member; 11a…bottom; 11b…longitudinal wall; 11c…longitudinal wall; 11d…roughly U-shaped cross section; 1 3…battery frame assembly; 15…bolt; 21…body side structure; 23…collision energy absorbing component; 23a…bottom; 23b…longitudinal wall; 23c…longitudinal wall; 23d…roughly U-shaped cross-section; 25…body side structure; 27…collision energy absorbing component; 27a…bottom; 27b…longitudinal wall; 27c…longitudinal wall; 27d…roughly U-shaped cross-section; 31…body side structure; 33…connecting component; 101…vehicle; 103…rod.

Claims

1. A vehicle body side structure comprising a side sill extending in a vehicle length direction, and a battery pack disposed on a vehicle interior side in a vehicle width direction relative to the side sill, The vehicle body side structure is characterized in that: A collision energy absorbing component is provided, the collision energy absorbing component has a substantially U-shaped cross-section, the substantially U-shaped cross-section has a bottom substantially parallel to the vehicle height direction, and a pair of longitudinal wall portions continuous from the upper end and the lower end of the bottom, the collision energy absorbing component ensures a space between the battery pack and the lower longitudinal beam on the outer peripheral side in the vehicle width direction, and is provided in a convex shape toward the outer side of the vehicle in the vehicle width direction, the collision energy absorbing component is composed of a steel plate having a tensile strength of 270 MPa or more and 340 MPa or less and a plate thickness of 1.0 mm or more and 1.4 mm or less, When a collision load is input to the lower side sill from the outer side of the vehicle in the vehicle width direction during a side collision, after the lower side sill deformed by the input collision load contacts the collision energy absorbing component, the collision energy absorbing component deforms to absorb the collision energy, thereby reducing the load transmitted to the battery pack.

2. The vehicle body side structure according to claim 1, characterized in that: The collision energy absorbing member is configured such that an aspect ratio of a height in a vehicle height direction to a width in a vehicle width direction is within a range of 0.4 to 2.

5.

3. The vehicle body side structure according to claim 1 or 2, characterized in that: The collision energy absorbing member is configured such that the pair of vertical wall portions are inclined in a direction approaching each other toward the outer side of the vehicle in the vehicle width direction.

4. The vehicle body side structure according to claim 1 or 2, characterized in that: The collision energy absorbing member is configured such that one of the longitudinal wall portions is parallel to a horizontal line in the vehicle width direction, and the other longitudinal wall portion is inclined toward the vehicle outer side in the vehicle width direction in a direction approaching the one longitudinal wall portion.

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