Battery pack

Abstract

To provide a technique capable of protecting the battery from impacts even with a small crash stroke in vehicles equipped with a battery.SOLUTION: The battery pack includes: a battery module, and a bracket attached to the battery module. The outer shell of the battery module includes: a first side that intersects at the intersection; and a second side. The bracket is connected to the intersection and is positioned opposite the first side. The bracket is spaced away from the first side except for the intersection.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a battery pack mounted on a vehicle.

Background Art

[0002] Patent Document 1 discloses a battery mounting structure for a vehicle. The battery mounting structure for the vehicle is configured such that the battery does not interfere with the vehicle body during impact by bracket connection between the battery and the vehicle body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor of the present application first recognized the following problem regarding the battery pack mounted on a vehicle. That is, when the battery mounting amount is increased, as a trade-off, the crush stroke, which is the extra length when an impact is applied, becomes smaller, and as a result, the battery is likely to be damaged. In an electric vehicle, the cruising range can be extended by increasing the battery mounting amount. On the other hand, an increase in the space occupied by the battery means a decrease in the crush stroke. A decrease in the crush stroke only increases the risk of the battery being damaged when an impact is applied.

[0005] One object of the present disclosure is to provide a technology that can protect the battery from impact even when the battery mounting amount is increased, that is, even when the crush stroke is small.

Means for Solving the Problems

[0006] The first aspect relates to a battery pack mounted on a vehicle. The battery pack is Battery module and A bracket that attaches to the battery module and It is equipped with. The outer casing of the battery module comprises a first side portion and a second side portion that intersect at the intersection. The bracket is positioned opposite the first side, connected to the intersection, and spaced apart from the first side except at the intersection.

[0007] The second perspective, in addition to the first perspective, has the following further characteristics: The bracket has legs and a weak point. The leg portion is adjacent to the intersection of the first and second side portions. The weak point is located further from the first lateral section than the leg section, and has lower rigidity than the leg section.

[0008] The third perspective, in addition to the second perspective, has the following further characteristics: The vulnerable portion of the bracket is located at the position furthest from the first side of the bracket.

[0009] The fourth perspective has the following additional characteristics in addition to any of the first to third perspectives: The bracket surface facing the first side has an arched shape.

[0010] The fifth perspective has the following additional characteristics in addition to any of the first to third perspectives: The first side section is installed facing the side of the vehicle. [Effects of the Invention]

[0011] From the first perspective, the bracket attached to the battery module casing and the first side of the casing are connected at an intersection, but separated elsewhere. Therefore, the load applied toward the first side of the battery module is transmitted to the second side of the casing via the bracket and the intersection. Since the transmission of load to the center of the first side is suppressed, the battery body within the battery module is protected from impact. Because the battery body is more easily protected from impact, it is possible to reduce the crash stroke. This contributes to an increase in battery capacity.

[0012] From a second perspective, the bracket is provided with a partially weakened section. The weakened section is set to have less rigidity compared to the legs of the bracket. When a load is applied toward the first side, the weakened section deforms or breaks first. The impact energy is absorbed by the deformation or breakage of the weakened section. This also contributes to the protection of the battery body within the battery module.

[0013] From a third perspective, the weakest point within the bracket is located at the position furthest from the first side. This position is closest to the outside and therefore most susceptible to impact loads. Consequently, placing the weakest point at the position furthest from the first side to absorb impact energy contributes to protecting the battery during impact.

[0014] From a fourth perspective, the surface of the bracket facing the first side is arch-shaped. This arch shape allows for efficient transmission of the load from the top of the arch towards the intersection.

[0015] According to the fifth aspect, the first side portion is positioned to face the side of the vehicle. This disclosure is particularly effective in the event of an impact from the side of the vehicle, where the crash stroke tends to be smaller compared to an impact in the longitudinal direction of the vehicle. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram showing an example of a vehicle equipped with a battery pack. [Figure 2] It is a perspective view for explaining a comparative example. [Figure 3] It is a schematic diagram for explaining a problem. [Figure 4] It is a schematic diagram showing a configuration example of a battery pack according to an embodiment of the present disclosure and its effects. [Figure 5] It is a perspective view showing a configuration example of a bracket according to an embodiment of the present disclosure. [Figure 6] It is a schematic diagram showing another configuration example of a battery pack according to an embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0017] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0018] 1. Main Configuration FIG. 1 is a schematic diagram of a vehicle 100 equipped with a battery pack 1. The x-axis direction shown in FIG. 1 corresponds to the front direction of the vehicle 100 equipped with the battery pack 1. Similarly, the y-axis direction corresponds to the left direction when viewed from the front of the vehicle 100, and the z-axis direction corresponds to the direction upward of the vehicle 100. The battery pack 1 is used, for example, as a power source for electric vehicles such as BEV, PEV, and HEV.

[0019] The battery pack 1 includes one or more battery modules 30 and a battery case 2. The one or more battery modules 30 are housed in the battery case 2.

[0020] FIG. 2 is a schematic diagram showing the configuration of a battery module 30 according to a comparative example.

[0021] As shown in (A) in FIG. 2, the battery module 30 can accommodate a battery stack 300 and includes an outer shell portion 31 for resisting a load input from outside the vehicle. That is, the battery stack 300 is housed in the outer shell portion 31. The battery stack 300 is composed of a number of battery cells integrated. The battery cell is a rechargeable secondary battery, for example, a lithium-ion secondary battery.

[0022] The outer shell 31 comprises a first side portion 10 and a second side portion 20. The first side portion 10 and the second side portion 20 intersect at the intersection 12. The first side portion 10 and the second side portion 20 may be perpendicular at the intersection 12. In the example shown in Figure 2, the first side portion 10 faces the side of the vehicle. The first side portion 10 is sometimes called an end plate. In addition to the first side portion 10 and the second side portion 20, the outer shell 31 may also have a bottom surface (a plane along the xy plane in Figure 2) and another surface parallel to the bottom surface, and may have a substantially rectangular parallelepiped shape.

[0023] As shown in (B) in Figure 2, the battery module 30 is connected to the battery case 2 by a connector 2A via a bracket 32A attached to the outer shell 31.

[0024] 2. Challenges The inventor of the present invention recognized for the first time the following problem with the battery pack 1 described above: Increasing the battery capacity reduces the crash stroke, which is the excess length when an impact is applied, and as a result the battery itself within the battery module becomes more susceptible to damage.

[0025] In electric vehicles, increasing the battery capacity can extend the driving range. However, a larger battery space means a smaller crash stroke. A smaller crash stroke increases the risk of damage to the battery itself in the event of an impact. Therefore, even with a larger battery capacity, i.e., a smaller crash stroke, a structure is required to protect the battery from impact. This is especially important in the event of an impact from the side of the vehicle, where the distance between the battery and the outside of the vehicle is short.

[0026] The load transmission during a side impact in the comparative example will be explained. As shown in Figure 3, in the comparative example, the bracket 32A is connected across the entire first side portion 10. Therefore, when a load 200 is applied to the first side portion 10 from the outside, the load 200 is transmitted to the entire first side portion 10 through the bracket 32A. Since the battery stack 300 is housed on the opposite side of the bracket 32A of the first side portion 10, in this case the load 200 is easily transmitted to the battery stack 300, and as a result the battery stack 300 is easily damaged.

[0027] 3. Features of this disclosure In the previous section, we discussed the risk of battery damage during impact due to the increased battery capacity. Therefore, in this embodiment, we propose a structure that reduces damage to the battery stack 300 by separating the bracket 32 ​​and the first side portion 10 and transmitting the load 200 to the second side portion 20 instead of the first side portion 10.

[0028] Figure 4 is a schematic diagram showing an example of the configuration of a battery pack 1 according to an embodiment of the present disclosure and its effects.

[0029] Figure 4(A) is a perspective view showing this embodiment. The bracket 32 ​​is connected to the intersection 12 of the first side portion 10 and the second side portion 20, and the first side portion 10 and the bracket 32 ​​are separated except at the intersection 12. As a result, as shown in Figure 4(B), the load 200 applied toward the first side portion 10 is transmitted from the bracket 32 ​​through the intersection 12 to the second side portion 20. This is expected to have the effect of protecting the battery stack 300 in the event of impact. Furthermore, because the battery stack 300 is more easily protected from impact, it is possible to reduce the crash stroke. This contributes to an increase in battery capacity.

[0030] Figure 5 is a perspective view showing an example configuration of the bracket 32 ​​according to an embodiment of the present disclosure.

[0031] As shown in (A) in Figure 5, a partially weakened portion 32a may be provided in the bracket 32. The weakened portion 32a is set to have less rigidity compared to the portion of the bracket 32 ​​adjacent to the first side portion 10 (leg portion 32b). When a load is applied toward the first side portion, the weakened portion 32a deforms or breaks first. The deformation or breakage of the weakened portion 32a absorbs the impact energy, contributing to the protection of the battery stack 300. As a method for realizing the weakened portion 32a, the cross-sectional area may be locally reduced, or the material may be locally changed.

[0032] Furthermore, as shown in (A) in Figure 5, the vulnerable portion 32a may be provided at the position furthest from the first side (position Y1). Position Y1 is the position closest to the outside of the vehicle, and therefore the position most susceptible to impact load. Thus, providing a vulnerable portion at position Y1 to absorb impact energy contributes to protecting the battery stack 300.

[0033] Furthermore, the shape of the bracket 32 ​​may be such that the surface 32c facing the first side portion 10 is arched, as shown in (B) in Figure 5. By making it arched, the load can be efficiently transmitted to the second side portion 20 via the leg portion 32b. Also, in the form in which an arched notch is provided in a rectangular plate as shown in the same figure, a wide shoulder portion 32d is formed on the bracket 32. Because the shoulder portion 32d is wide, a hole 32e for joining the bracket 32 ​​and the battery case 2 can be provided. This means that the bracket 32 ​​and the battery case 2 can be easily joined. Moreover, since the cross-sectional area is smallest at the top of the arch, the aforementioned weak point 32a is formed, and it can be expected that impact energy will be absorbed, contributing to the protection of the battery.

[0034] Figure 6 is a schematic diagram showing another configuration example of the battery pack 1 according to the embodiment of this disclosure.

[0035] Figure 6(A) shows a more specific embodiment. The first side portion 10 has a protrusion 13 adjacent to the intersection 12. As shown in the example in Figure 5(B), the bracket 32 ​​has an arched surface 32c facing the first side portion 10, and the leg portion 32b has thickness in the z-axis direction. The upper surface of the leg portion 32b is combined with the upper surface of the protrusion 13 without any step difference, forming a plane 33 along the xy plane. A connecting plate 40 is installed on the plane 33 so as to straddle the boundary between the protrusion 13 and the leg portion 32b. The protrusion 13 and the leg portion 32b are connected by bolts 41 that pass through the connecting plate 40.

[0036] In Figures 4 and 6(A), which show embodiments of this disclosure, the bracket 32 ​​and the first side portion 10 are in contact. However, the configuration of the intersection 12 may also be such that the bracket 32 ​​and the second side portion 20 are in contact, as shown in Figure 6(B). In other words, either the first side portion 10 or the second side portion 20 constituting the intersection 12 may be in contact with the bracket 32, and even if the second side portion 20 is in contact with the bracket 32, the effects of this disclosure can still be achieved.

[0037] The proposed battery pack 1 is particularly effective when the vehicle 100 is impacted from the side, where the crash stroke tends to be smaller compared to the longitudinal direction of the vehicle 100. However, the orientation of the battery pack 1 and the direction in which the impact is applied are not limited to this embodiment. [Explanation of Symbols]

[0038] 1: Battery pack, 2: Battery case, 10: First side, 20: Second side, 12: Intersection 13: protrusion, 30: battery module, 31: outer casing, 32: bracket 32a: Weak point, 32b: Leg, 40: Joint plate, 100: Vehicle, 200: Load 300: Battery Stack

Claims

1. A battery pack installed in a vehicle, Battery module and A bracket that attaches to the battery module and Equipped with, The outer shell of the battery module comprises a first side portion and a second side portion that intersect at the intersection, The bracket is positioned opposite the first side, connected to the intersection, and spaced apart from the first side except at the intersection. The bracket has a leg portion and a weak portion, The aforementioned leg portion is adjacent to the intersection, The weak portion is located further from the first side than the leg portion and has lower rigidity than the leg portion. Battery pack.

2. A battery pack according to claim 1, The weak portion is located at the position furthest from the first side of the bracket. Battery pack.

3. A battery pack according to claim 1 or 2, The surface of the bracket facing the first side portion has an arch shape. Battery pack.

4. A battery pack according to claim 1 or 2, The first side portion is installed so as to face the side of the vehicle. Battery pack.

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